Claims:

1. A dispensing device (102), comprising:
an outer barrel (104) that accommodates a cartridge (218) having a material to be delivered;
a dose-setting knob (106) that is rotationally coupled to the outer barrel (104) to set a desired dose of the material to be delivered;
a dose sleeve (202) comprising a proximal end (502) that is coupled to the dose-setting knob (106) and a distal end (508) that is coupled to the outer barrel (104), wherein the dose sleeve (202) is adapted to rotationally move within the outer barrel (104) by a designated distance corresponding to a rotation of the dose-setting knob (106) to set the desired dose;
a plunger (204) that extends out from a slot (514) of the dose sleeve (202), wherein one end of the plunger (204) is disposed within the cartridge (218);
a locking device (208) that is coupled to the plunger (204) and is adapted to hold the plunger (204) in a locked position while setting the desired dose;
an elastic member (212) disposed in a compressed state between the plunger (204) and the locking device (208); and
an unlocking device (210) disposed at least partially within the locking device (208) and adapted to release the plunger (204) from the locked position to an unlocked position upon being depressed, the depression causing an expansion of the elastic member (212), wherein the expansion of the elastic member (212) causes the plunger (204) to move linearly by the designated distance to release the set desired dose from the cartridge (218).

2. The dispensing device (102) as claimed in claim 1, wherein the dose-setting knob (106) comprises a locking mechanism (408) at a proximal end (410) of the dose-setting knob (106), a protrusion (412) disposed at a distal end (414) of the dose-setting knob (106), and a plurality of grooves (406A-D) disposed within the dose-setting knob (106).

3. The dispensing device (102) as claimed in claim 2, wherein the dose sleeve (202) further comprises a threaded portion (510) disposed at the distal end (508) of the dose sleeve (202) and a plurality of ribs (506A-D) disposed on an outer surface (504) at the proximal end (502) of the dose sleeve (202).

4. The dispensing device (102) as claimed in claim 3, wherein the threaded portion (510) disposed at the distal end (508) of the dose sleeve (202) is coupled to a threaded section (304) disposed at a proximal end (302) of the outer barrel (104).

5. The dispensing device (102) as claimed in claim 3, wherein each of the plurality of ribs (506A-D) fits within a corresponding groove in the plurality of grooves (406A-D) to couple the dose sleeve (202) and the dose-setting knob (106) together.

6. The dispensing device (102) as claimed in claim 5, wherein the plunger (204) comprises a cylindrical body portion (602) having an open end (610) inside which one end (1004) of the elastic member (212) is seated, and a rod (614) that is disposed within the cylindrical body portion (602) and extends from a proximal end (114) towards a distal end (116) of the dispensing device (102), wherein the rod (614) comprises a ratchet (620) having a plurality of teeth (622) disposed at a proximal portion (616) of the rod (614).

7. The dispensing device (102) as claimed in claim 6, further comprising a lock nut (206) that comprises a slot (902) through which the rod (614) of the plunger (204) passes through, wherein a profile of the slot (902) and a profile of the rod (614) are selected such that the lock nut (206) is adapted to allow only a linear motion of the plunger (204) during release of the set desired dose.

8. The dispensing device (102) as claimed in claim 6, wherein the locking device (208) comprises
a collar (702), wherein another end (1006) of the elastic member (212) rests against the collar (702);
an elongated member (704) having an opening (706) at a proximal end (708) of the elongated member (704), wherein the proximal portion (616) of the rod (614) having the ratchet (620) is disposed within the opening (706) of the elongated member (704); and
at least a first flexible pawl (712A) and a second flexible pawl (712B) disposed at a distal end (710) of the elongated member (704).

9. The dispensing device (102) as claimed in claim 8, wherein the first flexible pawl (712A) and the second flexible pawl (712B) are secured to a first tooth (1008) of the ratchet (620) to hold the plunger (204) in the locked position before releasing a set first dose from the dispensing device (102).

10. The dispensing device (102) as claimed in claim 9, wherein the unlocking device (210) comprises a thumb pad (802) that comprises a stem portion (804) disposed within the locking device (208) via the opening (706) at the proximal end (708) of the elongated member (704) such that the stem portion (804) is located between the ratchet (620) and the elongated member (704).

11. The dispensing device (102) as claimed in claim 10, wherein a depression of the thumb pad (802) causes the stem portion (804) to flex up the first and second flexible pawls (712A-B) to release the plunger (204) from the locked position to the unlocked position, and thereby causing the expansion of the elastic member (212), wherein the expansion of the elastic member (212) causes the plunger (204) to move linearly by a selected distance towards the distal end (116) of the dispensing device (102) to release the set first dose, wherein the selected distance corresponds to the distance by which the dose sleeve (202) moves while setting the first dose using the dose-setting knob (106).

12. The dispensing device (102) as claimed in claim 11, wherein the first and second flexible pawls (712A-B) are secured to another tooth (1402) of the ratchet (620) post-delivery of the set first dose from the dispensing device (102) due to the linear movement of the plunger (204).

13. The dispensing device (102) as claimed in claim 12, wherein the dose sleeve (202) is configured to rotationally move within the outer barrel (104) during dose setting by a corresponding distance based on a rotational motion of the dose-setting knob (106) and is further adapted to be seated against a cartridge (218) provided within the outer barrel (104) after a final dose is delivered from the dispensing device (102).
, Description:

BACKGROUND

[0001] Embodiments of the present specification relate generally to a dispensing device, and more particularly to a dispensing device that is capable of delivering variable amount of substances based on corresponding volumes set by a user.
[0002] Generally, treating patients suffering from various diseases entails injecting medication substances using syringe devices. One example of a simple syringe device includes a transparent medication barrel that includes graded scale markings marked on a cylindrical external surface of the transparent medication barrel. The graded scale markings allow a caregiver to set a desired dose to be injected into a patient’s body. A proximal end of the transparent medication barrel includes a plunger, and a stopper that is placed within the medication barrel and is coupled to one end of the plunger. A distal end of the transparent medication barrel is designed and is shaped to couple to a needle that pierces patient’s skin for injecting a medication substance by actuating the plunger.
[0003] The amount of substance to be injected is set by piercing the needle through a rubber stopper of a container carrying a medication substance and by pulling out the plunger towards the distal end. The plunger is pulled out towards the distal end until level of the medication substance within the medication barrel corresponds to a desired graded scale marking. Then, the syringe device is primed to remove any air bubbles that may be formed while setting the dose and it is ensured that the syringe device is carrying only the desired amount of medication substance to be injected. Then, the set dose is injected by pushing the plunger towards the proximal end, during which time, the plunger along with the stopper moves within the transparent medication barrel. Movement of the plunger and stopper within the transparent medication barrel causes the enclosed medicament substance to pass out through the needle.
[0004] When treating certain diseases or disorders, the treatment may require multiple doses of same or variable amount of materials to be injected at designated intervals in the day or in a week. For such cases, injector pens have been developed that allow patients to set a variable dose of medication and deliver a desired dose each time by themselves more accurately in a controlled manner. Such injector pens, in general, have a cartridge that contains a rubber stopper and a multi-dose quantity of medication substance. In addition, a proximal end of the injector pens includes a driving member that operably connects to the rubber stopper at a distal end of the injector pens. While delivering a set desired dose, the driving member moves towards the distal end and pushes the rubber stopper to dispense the set desired dose from the cartridge.
[0005] Most often, the injector pens are designed such that the patients would not be able to re-use the injector pens once a final dose is delivered and the cartridge is empty. Generally, certain mechanisms are built into the injector pens to avoid risks associated with re-using of the injector pens. These risks include microbial growth and contamination at the needle tip, experiencing pain when injecting the medication substance, breaking off the needle, formation of lumps on the skin, etc. However, the existing injector pens use complex mechanisms and expensive components to set variable doses, to deliver the set variable doses, and to prevent re-using of the pens after their end of life (EOL).
[0006] Accordingly, there remains a need for a dispensing device that has in-built mechanisms that execute all the functionalities of the typical injector pens, but is still cost-effective, more efficient, has improved accuracy in setting and delivering variable doses and prevents re-using of the dispensing device after its EOL.

BRIEF DESCRIPTION

[0007] It is an objective of the present disclosure to provide a dispensing device. The dispensing device includes an outer barrel that accommodates a cartridge having a material to be delivered, a dose-setting knob that is rotationally coupled to the outer barrel to set a desired dose of the material to be delivered, and a dose sleeve. The dose sleeve includes a proximal end that is coupled to the dose-setting knob and a distal end that is coupled to the outer barrel. The dose sleeve is adapted to rotationally move within the outer barrel by a designated distance corresponding to the set desired dose. The dispensing device further includes a plunger that extends out from a slot of the dose sleeve, wherein one end of the plunger is disposed within the cartridge. The dispensing device also includes a locking device that is coupled to the plunger and is adapted to hold the plunger in a locked position while setting the desired dose, an elastic member disposed in a compressed state between the plunger and the locking device. An unlocking device disposed at least partially within the locking device to release the plunger from the locked position to an unlocked position causing an expansion of the elastic member. The expansion of the elastic member causes plunger to move linearly within the outer barrel by the designated distance to release the set desired dose from the cartridge.
[0008] The dose-setting knob may include a locking mechanism at a proximal end of the dose-setting knob, a protrusion disposed at a distal end of the dose-setting knob, and a plurality of grooves disposed within the dose-setting knob. The dose sleeve may further include a threaded portion disposed at the distal end of the dose sleeve and a plurality of ribs disposed on an outer surface at the proximal end of the dose sleeve. The threaded portion disposed at the distal end of the dose sleeve may be coupled to a threaded section disposed at a proximal end of the outer barrel. Each of the plurality of ribs may fit within a corresponding groove in the plurality of grooves to couple the dose sleeve and the dose-setting knob together.
[0009] The plunger may include a cylindrical body portion having an open end inside which one end of the elastic member is seated, and a rod that is disposed within the cylindrical body portion and extends from a proximal end towards a distal end of the dispensing device. The rod may include a ratchet having a plurality of teeth disposed at a proximal portion of the rod. A lock nut of the dispensing device may include a slot through which the rod of the plunger passes through, wherein a profile of the groove and a profile of the rod are selected such that the lock nut is adapted to allow only a linear motion of the plunger during release of the set desired dose.
[0010] The locking device may include a collar. Another end of the elastic member may rest against the collar. An elongated member may include an opening at a proximal end of the elongated member. The proximal portion of the rod having the ratchet may be disposed within the opening of the elongated member. At least a first flexible pawl and a second flexible pawl may be disposed at a distal end of the elongated member. The first flexible pawl and the second flexible pawl are secured to a first tooth of the ratchet to hold the plunger in the locked position before releasing a set first dose from the dispensing device.
[0011] The unlocking device may include a thumb pad that includes a stem portion disposed within the locking device via the opening at the proximal end of the elongated member such that the stem portion is located between the ratchet and the elongated member. A depression of the thumb pad may cause the stem portion flex up the first and second flexible pawls to release the plunger from the locked position to the unlocked position, and thereby, causing the expansion of the elastic member. The expansion of the elastic member may cause the plunger to move linearly towards the distal end of the dispensing device by a selected distance to release the set first dose. The selected distance may correspond to the distance by which the dose sleeve moves while setting the first dose using the dose-setting knob.
[0012] The first and second flexible pawls may be secured to another tooth of the ratchet post-delivery of the set first dose from the dispensing device due to the linear movement of the plunger. The dose sleeve may be configured to rotationally move within the outer barrel during dose setting by a corresponding distance based on a rotational motion of the dose-setting knob and is further adapted to be seated against a cartridge provided within the outer barrel after a final dose is delivered from the dispensing device.

DRAWINGS

[0013] These and other features, aspects, and advantages of the claimed subject matter will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0014] FIG. 1 illustrates a side perspective view depicting an exemplary dispensing device that is configured to deliver variable amounts of materials based on corresponding doses set by a user;
[0015] FIG. 2 illustrates an exploded view of the exemplary dispensing device of FIG. 1;
[0016] FIG. 3 illustrates a side perspective view of an outer barrel of the exemplary dispensing device of FIG. 1;
[0017] FIG. 4 illustrates a top perspective view of a dose-setting knob of the exemplary dispensing device of FIG. 1;
[0018] FIG. 5 illustrates a side perspective view of a dose sleeve of the exemplary dispensing device of FIG. 1;
[0019] FIG. 6 illustrates a top perspective view of a plunger of the exemplary dispensing device of FIG. 1;
[0020] FIG. 7 illustrates a side perspective view of a locking device of the exemplary dispensing device of FIG. 1;
[0021] FIG. 8 illustrates a side perspective view of an unlocking device of the exemplary dispensing device of FIG. 1;
[0022] FIG. 9 illustrates a front perspective view of a lock nut of the exemplary dispensing device of FIG. 1;
[0023] FIG. 10 illustrates a cross-sectional view of the exemplary dispensing device of FIG. 1 depicting arrangements of various components of the exemplary dispensing device before delivery of a first dose;
[0024] FIG. 11 illustrates another cross-sectional view of the exemplary dispensing device of FIG. 1 depicting the dose sleeve of FIG. 2 moved from an initial position to an intermediate position by a first distance;
[0025] FIG. 12 illustrates another cross-sectional view of the exemplary dispensing device of FIG. 1 depicting first and second flexible pawls of the locking device of FIG. 2 in a flexed up position;
[0026] FIG. 13 illustrates another cross-sectional view of the exemplary dispensing device of FIG. 1 depicting the plunger of FIG. 2 moved by the first distance;
[0027] FIG. 14 illustrates another cross-sectional view of the exemplary dispensing device of FIG. 1 depicting the first and second flexible pawls when positioned on a fifth ratchet tooth of the plunger of FIG. 2;
[0028] FIG. 15 illustrates another cross-sectional view of the exemplary dispensing device of FIG. 1 depicting the dose sleeve of FIG. 2 when disposed in an engaged state with respect to the cartridge;
[0029] FIG. 16 illustrates a front view of the plunger of FIG. 2;
[0030] FIG. 17 illustrates an exemplary view of a label affixed on a cylindrical body portion of the plunger of FIG. 2;
[0031] FIG. 18 illustrates a cross sectional view of an arrangement of the dose-setting knob and the plunger of FIG. 2, in which a protrusion of the dose-setting knob is placed in an unlocked state with respect to a stopper associated with the plunger; and
[0032] FIG. 19 illustrates another cross sectional view of an arrangement of the dose-setting knob and the plunger of FIG. 2, in which the protrusion of the dose-setting knob is placed in a locked state with respect to another stopper associated with the plunger.

DETAILED DESCRIPTION

[0033] The following description presents an exemplary dispensing device that includes a variable dose-setting mechanism that allows a user to adjust and set a desired amount of material (e.g., a medicament) to be dispensed from the dispensing device. To that end, various components are provided in the dispensing device that allows the user to vary a dose of a material to be dispensed, prevents the user from setting a subsequent dose after a final dose is delivered, and limits a maximum amount of dose that can be delivered by a single actuation of the dispensing device. The dispensing device further allows the user to set a final dose to be delivered according to an amount of material remaining in a cartridge. The term “dose,” used in the various embodiments described herein, broadly refers to a volume of a material to be dispensed out. Examples of the material include but are not limited to a medicament, a chemical substance, and a composition of substances. Certain exemplary configurations of the dispensing device that provides the aforementioned features and functions are described in greater detail with reference to FIGS. 1 through 19.
[0034] FIG. 1 illustrates a side perspective view (100) of an exemplary dispensing device (102) that is configured to deliver variable amount of materials based on corresponding doses set by a user. In one embodiment, the dispensing device (102) is a medication-dispensing device having an appearance of a pen. The dispensing device (102) is a disposable device that is configured so as not to be reused once a final dose of medication is delivered from the dispensing device (102).
[0035] To that end, in certain embodiments, the dispensing device (102) includes an outer barrel (104) and a dose-setting knob (106) that is rotationally coupled to the outer barrel (104). In one embodiment, the dose-setting knob (106) is rotationally coupled to the outer barrel (104) such that the dose-setting knob (106) exhibits only rotational motion with respect to the outer barrel (104), and translational motion of the dose-setting knob (106) is arrested in all directions. For setting a desired dose to be delivered, a user is required to simply rotate the dose-setting knob (106) in a designated direction, for example, a clockwise direction or in an anticlockwise direction with respect to the outer barrel (104).
[0036] For varying the set dose, for example, for incrementing the set dose, the dose-setting knob (106) may be rotated in a specific direction (e.g., a clockwise direction) with respect to the outer barrel (104). For decrementing the set dose, the dose-setting knob (106) may be rotated in an opposite direction, for example in an anti-clockwise direction with respect to the outer barrel (104).
[0037] In one embodiment, the dose-setting knob (106) includes a dose indicator window (108) that is disposed on an outer surface (110) of the dose-setting knob (106) to visually indicate the set dose for delivery. In one embodiment, the dose indicator window (108) includes a cover (112) that is made up of a transparent material (e.g., a glass material) through which at least one dosage number corresponding to the set dose can be visually perceived by the user.
[0038] In certain embodiments, the cover (112) is made up of a material that acts as a magnification lens to magnify the dosage number corresponding to the set dose such that the user can easily perceive the set dose in a magnified view. In one embodiment, the dispensing device (102) includes a proximal end (114) having an actuation mechanism for dispensing the set dose and a distal end (116) for securing the needle that delivers the set dose of medication to a patient. Various components of the dispensing device (102) for use in dispensing variable amounts of a material are depicted and described in greater detail with reference to FIGS. 2 through 18.
[0039] FIG. 2 illustrates an exploded view (200) of the exemplary dispensing device (102) of FIG. 1. In one embodiment, the dispensing device (102) further includes a dose sleeve (202), a plunger (204), a lock nut (206), a locking device (208), an unlocking device (210), a first elastic member (212), a housing top (214), a second elastic member (216), and a cartridge (218). Each of these components of the dispensing device (102) is depicted and described in detail in subsequent figures and paragraphs.
[0040] FIG. 3 illustrates a side perspective view (300) of the outer barrel (104) of the exemplary dispensing device (102) of FIG. 1. In one embodiment, the outer barrel (104) acts as an exterior cover inside which the cartridge (218), which carries a material to be dispensed out from the dispensing device (102), is accommodated. Further, a proximal end (302) of the outer barrel (104) includes a threaded section (304) that may be coupled to a threaded portion (510) (shown in FIG. 5) associated with the dose sleeve (202) when various components of the dispensing device (102) depicted in FIG. 2 are assembled. In one embodiment, the threaded section (304) at the proximal end (302) enables the dose sleeve (202) to move within the outer barrel (104) towards the proximal end (114) of the dispensing device (102) while rotating the dose-setting knob (106) in an anticlockwise direction. The threaded section (304) also enables the dose sleeve (202) to move within the outer barrel (104) towards the distal end (116) of the dispensing device (102) while rotating the dose-setting knob (106) in a clockwise direction, as described in greater detail with reference to FIG. 5.
[0041] FIG. 4 illustrates a top perspective view (400) of the dose-setting knob (106) of the exemplary dispensing device (102) of FIG. 1. In one embodiment, the dose-setting knob (106) is a cylindrical shaped body that can be rotated to set a dose and vary the set dose if required, as noted previously. In certain embodiments, the dose-setting knob (106) includes a coupling mechanism that enables coupling of the dose-setting knob (106) to the dose sleeve (202). In one embodiment, the coupling mechanism is disposed within an internal cylindrical body (402) of the dose-setting knob (106). The coupling mechanism includes one or more sets of elevated walls.
[0042] For example, FIG. 4 depicts the coupling mechanism having four sets of elevated walls including a first set of elevated walls (404A), a second set of elevated walls (404B), a third set of elevated walls (404C), and a fourth set of elevated walls (404D) that is only partially visible in FIG. 4. Though FIG. 4 depicts the coupling mechanism having four such sets of elevated walls (404A-D), the dose-setting knob (106) can have any number of sets of elevated walls. Further, the coupling mechanism includes a corresponding groove disposed between each of the sets of elevated walls (404A-D). For example, a first groove (406A) is disposed between the first set of elevated walls (404A).
[0043] Similarly, it is to be understood that a second groove (406B), a third groove (406C), and a fourth groove (406D) (not visible in FIG. 4) are disposed between the second set of elevated walls (404B), the third set of elevated walls (404C), and the fourth set of elevated walls (404D), respectively. While assembling together various components of the dispensing device (102), the dose sleeve (202) is positioned within the internal cylindrical body (402) of the dose-setting knob (106) and is secured to the dose-setting knob (106) using a tongue and groove coupling mechanism, as described in detail with reference to FIG. 5. In one embodiment, the dose-setting knob (106) and the dose sleeve (202) can be coupled to each other using intermediate components that are used to scale down or scale up the transfer of rotational motion of the dose-setting knob (106). For example, if the dose-setting knob (106) is rotated by 180 degrees, then the dose sleeve (202) can be configured to rotate by 90 degrees. In another example if the dose-setting knob (106) is rotated by 180 degrees, then the dose sleeve (202) can be configured to rotate by 360 degrees based on specific requirement.
[0044] Alternatively, a rotational degree of the dose-setting knob (106) corresponds to a rotational degree of the dose sleeve (202). For example if the dose-setting knob (106) is rotated by 90 degrees, then the dose sleeve (202) is also configured to rotate by 90 degrees. In addition to the coupling mechanism disposed within the internal cylindrical body (402), a threaded arrangement (408) is disposed at a proximal end (410) of the dose-setting knob (106) for coupling the dose-setting knob (106) to the housing (214) that acts as a top protection cover for the dispensing device (102). In another embodiment, a locking mechanism is disposed at the proximal end (410) of the dose-setting knob (106) instead of the threaded arrangement (408) for locking the dose-setting knob (106) to the housing (214). Further, a protrusion (412) is disposed at a distal end (414) of the dose-setting knob (106). The protrusion (412), along with the plunger (204), is adapted to limit a maximum amount of dose that can be delivered by a single actuation of the dispensing device (102), as described in greater detail with reference to FIG. 17. The coupling mechanism that enables securing the dose-setting knob (106) and the dose sleeve (202) together is described in detail with reference to FIG. 5.
[0045] FIG. 5 illustrates a side perspective view (500) of the dose sleeve (202) of the exemplary dispensing device of FIG. 1. In certain embodiments, the dose sleeve (202) is a hollow elongated body having a proximal end (502) that includes a plurality ribs disposed at an outer surface (504) of the dose sleeve (202). While assembling various components of the dispensing device (102), the dose sleeve (202) is placed within the dose-setting knob (106) and the plurality of ribs is fitted into grooves (406A-D) associated with the dose-setting knob (106) to couple the dose-setting knob (106) to the dose sleeve (202). For example, FIG. 5 depicts four such ribs including a first rib (506A), a second rib (506B), a third rib (506C), and a fourth rib (506D) that fit within the first groove (406A), the second groove (406B), the third groove (406C), and the fourth groove (406D), respectively. Further, a distal end (508) of the dose sleeve (202) includes a threaded portion (510) that is secured against the threaded section (304) associated with the outer barrel (104).
[0046] When a user sets or adjusts a desired dose by rotating the dose-setting knob (106), the dose sleeve (202) rotates along with the dose-setting knob (106) as the dose sleeve (202) and the dose-setting knob (106) are coupled to each other. Further, the threaded portion (510) of the dose sleeve (202) slips against the threaded section (304) of the outer barrel (104) such that the dose sleeve (202) exhibits trans-rotational motion. The trans-rotational motion causes the dose sleeve (202) to move within the outer barrel (104) towards the proximal end (114) or the distal end (116) based on a rotational direction of the dose-setting knob (106). For example, the dose sleeve (202) advances and moves towards the distal end (116) of the dispensing device (102) when the dose-setting knob (106) is rotated in a clockwise direction during the process of incrementing the dose to be delivered.
[0047] In another example, the dose sleeve (202) moves in a reverse direction towards the proximal end (114) of the dispensing device (102) when the dose-setting knob (106) is rotated in an anti-clockwise direction during the process of decrementing the dose to be delivered. In one embodiment, the dose sleeve (202) includes a slot (514) through which the plunger (204) of the dispensing device (102) passes and moves towards the distal end (116) of the dispensing device (102) to deliver a set dose from the dispensing device (102).
[0048] FIG. 6 illustrates a top perspective view (600) of the plunger (204) of the exemplary dispensing device (102) of FIG. 1. In certain embodiments, the plunger (204) is configured to execute various significant functionalities in the dispensing device (102). Firstly, the plunger (204) is configured to limit a maximum amount of a material that can be set and dispensed at once from the dispensing device (102) for safety purposes. For example, in a particular scenario, a volume associated with the cartridge (218) is 3 ml and the cartridge (218) is filled with 2 ml of a material to be dispensed. In this example, a maximum dose that can be set by a user at once by rotating the dose-setting knob (106) is 300 international unit (IU) that corresponds to 0.5 ml.
[0049] When the user has already set the maximum dose of 0.5 ml for delivery and further attempts to dial the dose-setting knob (106) for increasing the set dose, the plunger (204) prevents rotation of the dose-setting knob (106). In addition, the plunger (204) is configured to allow the user to set a final dose to be delivered according to an amount of material that is left in the cartridge (218). For example, in a particular scenario, the cartridge (218) is left with only 0.3 ml of the material as the user has already used the remaining 1.7 ml. In this example, the plunger (204) ensures that the user can set a maximum final dose that can be delivered as 0.3 ml. If the user attempts to set a dose, for example, 0.5 ml, which is more than the amount of material left in the cartridge (218), the plunger (204) prevents rotation of the dose-setting knob (106) after 0.3 ml is set for delivery.
[0050] In order to prevent undesirable rotation of the dose-setting knob (106), in one embodiment, the plunger (204) is provided with a cylindrical body portion (602). The cylindrical body portion (602) includes a final dose limiter (1602) and at least one layer of stoppers (1606, 1608, and 1610) that are helically arranged on an outer surface (608) of the cylindrical body portion (602), as depicted in FIG. 16. The final dose limiter (1602) is configured to enable the functionality of allowing the user to set the final dose according to the remaining amount of material in the cartridge (218). Whereas, the at least one layer of stoppers (1606, 1608, and 1610) is configured to enable the functionality of limiting the maximum dose that can be set and be dispensed at once, as described in detail with reference to FIGS. 16 through 18.
[0051] In one embodiment, although FIG. 6 depicts a shape of the body portion (602) of the plunger (204) to be cylindrical, in other embodiments, the body portion (602) can be of any desired shape. For example, the body portion (602) can be of a rectangular shape instead of a cylindrical shape. In certain embodiments, one end (610) of the cylindrical body portion (602) is open, whereas another end (612) of the cylindrical body portion (602) is sealed such that the end (612) is not open. Further, as depicted in FIG. 6, the plunger (204) includes a rod (614) that is disposed within the cylindrical body portion (602) and extends from the proximal end (114) towards the distal end (116) of the dispensing device (102).
[0052] In one embodiment, the rod (614) includes a proximal portion (616) and a distal portion (618) that is adapted to pass through and be secured to the lock nut (206) to enable a linear motion of the plunger (204) while delivering a set dose, as described in detail with reference to FIG. 9. Whereas, the proximal portion (616) of the rod (614) includes a ratchet (620) that includes a plurality of teeth (622) to which the locking device (208) is configured to be secured in a locked position during a dose setting stage, as described in greater detail with reference to FIG. 7.
[0053] FIG. 7 illustrates a side perspective view (700) of the locking device (208) of the exemplary dispensing device (102) of FIG. 1. In one embodiment, the locking device (208) includes a collar (702), an elongated body (704) that extends from the collar (702), and an opening (706) (not visible in FIG. 7) at one end (708) of the elongated body (704). In one embodiment, the locking device (208) is secured between the dose sleeve (202) and the housing top (214) and is rotatable with respect to the dose-setting knob (106). In certain embodiments, the locking device (208) needs to hold the plunger (204) in a locked position while setting a desired dose to be delivered to prevent the plunger (204) from exhibiting motion. To that end, the locking device (208) is provided with at least one flexible pawl that is disposed at another end (710) of the elongated body (704).
[0054] FIG. 7 depicts the locking device (208) including four flexible pawls, out of which only two flexible pawls are visible, namely a first flexible pawl (712A) and a second flexible pawl (712B) that are disposed at the end (710) of the elongated body (704). As noted previously, the locking device (208) can have any number of flexible pawls. However, for the sake of simplicity, the following embodiments will be described with respect to only two flexible pawls (712A-B). The first and second flexible pawls (712A-B) are configured to be positioned in an engaged state with at least one teeth in the ratchet (620) to hold the plunger (204) in the locked position while setting the desired dose using the dose-setting knob (106).
[0055] In one embodiment, the first and second flexible pawls (712A-B) that are placed in the engaged state with at least one teeth in the ratchet (620) need to be disengaged, once the desired dose is set, to deliver the set dose from the dispensing device (102). To that end, the unlocking device (210) is provided that is operatively coupled to the locking device (208) to disengage the first and second flexible pawls (712A-B) from the ratchet (620) and to release the plunger (204) from the locked position to an unlocked position, as explained in greater detail with reference to FIG. 8.
[0056] FIG. 8 illustrates a side perspective view (800) of the unlocking device (210) of the exemplary dispensing device (102) of FIG. 1. In one embodiment, the unlocking device (210) includes a thumb pad (802) that needs to be depressed towards the distal end (116) of the dispensing device (102) for dispensing the set dose. The unlocking device (210) further includes a stem portion (804) that is placed in a ready position within the opening (706) of the locking device (208) to flex up the first and second flexible pawls (712A-B) associated with the locking device (208). When a user depresses the thumb pad (802) to dispense the set dose, the stem portion (804) moves further from the ready position within the opening (706) and flexes up the first and second flexible pawls (712A-B) such that the first and second flexible pawls (712A-B) are disengaged from the ratchet (620). Thereby, the plunger (204) is released from the locked position to the unlocked position and is free to move linearly towards the distal end (116) of the dispensing device (102) to release the set dose. In certain embodiments, the plunger (204) is secured to the lock nut (206) to constrain motion of the plunger (204) to a linear motion and to avoid the plunger (204) from exhibiting a rotational motion while delivering the dose, as described in greater detail with reference to FIG. 9.
[0057] FIG. 9 illustrates a front perspective view (900) of the lock nut (206) of the exemplary dispensing device (102) of FIG. 1. In one embodiment, the lock nut (206) includes a slot (902) through which the distal portion (618) of the rod (614) associated with the plunger (204) passes through. In addition, a profile of the slot (902) is selected such that the selected profile of the slot (902) has flat surfaces and corresponds to a profile of the distal portion (618) of the rod (614). For example, if the profile of the distal portion (618) is square, then the profile of the slot (902) is also square. As a result, the plunger (204) would not get adequate space to exhibit rotational motion as the distal portion (618) fits exactly into the slot (902) without leaving any gaps, and hence, the plunger (204) can exhibit only the linear motion while delivering the set dose. Certain exemplary arrangements of the plunger (204) with respect to the dose sleeve (202), the locking device (208) with respect to the dose sleeve (202) and the plunger (204), and the first elastic member (212) that are required to set and deliver a dose are depicted and explained in detail with reference to FIG. 10.
[0058] FIG. 10 illustrates a cross-sectional view (1000) of the exemplary dispensing device (102) of FIG. 1 depicting arrangements of various components of the exemplary dispensing device (102) before injecting a first dose of a medicament into a user. In one embodiment, the plunger (204) is placed within the slot (514) associated with the dose sleeve (202) such that the end (612) of the cylindrical body portion (602) of the plunger (204) is seated against the distal end (508) of the dose sleeve (202). Further, the distal portion (618) of the rod (614) associated with the plunger (204) is rested against a rubber stopper (1002) that is placed inside the cartridge (218). Alternatively, the distal portion (618) of the rod (614) is coupled to the rubber stopper (1002) via a butt joint. The proximal portion (616) of the plunger (204) having the ratchet (620) is disposed within the opening (706) provided in the elongated body (704) of the locking device (208).
[0059] The locking device (208) is disposed within the dose-setting knob (106) such that the collar (702) of the locking device (208) is placed in proximity to the proximal end (502) of the dose sleeve (202). Further, the locking device (208) having the first and second flexible pawls (712A-B) is placed in an engaged state with respect to a first tooth of the ratchet (620), as depicted in FIG. 10, before delivering the first dose of the medicament from the dispensing device (102). In one embodiment, the first elastic member (212) is located between the plunger (204) and the locking device (208).
[0060] The first elastic member (212) is disposed between the cylindrical body portion (602) of the plunger (204) and the locking device (208). More particularly, a first end (1004) of the first elastic member (212) is seated on the end (612) of the cylindrical body portion (602) and a second end (1006) of the first elastic member (212) is rested against the collar (702) of the locking device (208). In certain embodiments, the first elastic member (212) is a high-tension spring that is placed in a compressed state between the cylindrical body portion (602) and the locking device (208) before delivering a first dose of the medicament from the dispensing device (102). The first elastic member (212) stores energy required to dispense an entire volume of a material from the cartridge (218). Further, the first elastic member (212) pushes the plunger (204) towards the distal end (116) of the dispensing device (102) for delivering the set dose, as explained in greater detail in subsequent paragraphs.
[0061] For setting the first dose to be delivered from the dispensing device (102), the dose-setting knob (106) is rotated in a desired direction, for example in a clockwise direction. The dose sleeve (202) rotates along with the dose-setting knob (106) as the dose sleeve (202) and the dose-setting knob (106) are operatively coupled to each other using the tongue and groove coupling mechanism, as previously described with reference to FIGS. 4 and 5. Further, the threaded portion (510) (depicted in FIG. 5) of the dose sleeve (202) slips against the threaded section (304) of the outer barrel (104) when the dose sleeve (202) rotates along with the dose-setting knob (106) in the desired direction. Therefore, the dose sleeve (202) moves trans-rotationally within the outer barrel (104) by a first distance towards the distal end (116) of the dispensing device (102).
[0062] FIG. 11 illustrates another cross-sectional view (1100) of the exemplary dispensing device (102) depicting the dose sleeve (202) moved from an initial position (as depicted in FIG. 10) to an intermediate position by a first distance towards the distal end (116) of the dispensing device (102), as a result of the rotation of the dose-setting knob (106). In certain embodiments, the first distance by which the dose sleeve (202) moves corresponds to the first dose that is set.
[0063] For example, if the first dose that is set for delivery is 37.5 IU, then the first distance by which the dose sleeve (202) moves towards the distal end (116) is 1 millimeter (mm) that corresponds to delivery of 0.08 ml of the material from the cartridge (218). In another example, if the first dose that is set of delivery is 75 IU, then the first distance by which the dose sleeve (202) moves towards the distal end (116) is 2 mm that corresponds to delivery of 0.16 ml of the material from the cartridge (218). In one embodiment, a manufacturer of the dispensing device (102) defines a distance by which the dose sleeve (202) is supposed to move upon setting a desired dose to be delivered by selecting an appropriate corresponding pitch for the threaded section (304) of the outer barrel (104) and/or the threaded portion (510) of the dose sleeve (202).
[0064] In one embodiment, the unlocking device (210) is configured to not protrude out of the proximal end (114) of the dispensing device (102) while setting variable doses to be delivered from the dispensing device (102). Further, as depicted in FIG. 10, the unlocking device (210) is secured within the housing top (214) and the second elastic member (216) is placed between the locking device (208) and the unlocking device (210) in a relaxed state.
[0065] A user may set the first dose to be delivered by rotating the dose-setting knob (106), and use a needle disposed at the distal end (116) of the dispensing device (102) to pierce his/her skin and press the unlocking device (210) downwards towards the distal end (116). More particularly, the thumb pad (802) that is part of the unlocking device (210) and is projected out of the dispensing device (102) is depressed downwards towards the distal end (116). Upon depressing the thumb pad (802), the stem portion (804) that is placed in a ready position within the opening (706) in between the ratchet (620) and the elongated body (704) flexes up the first and second flexible pawls (712A-B) that are placed in an engaged state with respect to a first tooth (1008) of the ratchet (620). Consequently, the first and second flexible pawls (712A-B) are disengaged from the first tooth (1008), and thus, the plunger (204) is released from the locked position to the unlocked position.
[0066] FIG. 12 illustrates another cross-sectional view (1200) of the exemplary dispensing device (102) of FIG. 1 depicting the first and second flexible pawls (712A-B) in a flexed up position following actuation of the unlocking device (210) towards the distal end (116) of the dispensing device (102). Further, FIG. 12 depicts the first and second flexible pawls (712A-B) placed in a disengaged state with respect to the first tooth (1008) of the ratchet (620). Once the first and second flexible pawls (712A-B) are placed in the disengaged state, the first elastic member (212) that is placed within the cylindrical body portion (602) of the plunger (204) expands towards the distal end (116) and exerts a force on the plunger (204) to push the plunger (204) towards the distal end (116). In one embodiment, the expansion of the first elastic member (212) causes the plunger (204) to move by a distance, which is same as the first distance by which the dose sleeve (202) had moved earlier while setting the first dose.
[0067] FIG. 13 illustrates another cross-sectional view (1300) of the exemplary dispensing device (102) of FIG. 1 depicting the plunger (204) at a position post moved by the first distance towards the distal end (116). The movement of the plunger (204) by the first distance causes the rubber stopper (1002) to move by the same distance, resulting in injecting the first dose of the medicament into the user. In certain embodiments, the plunger (204) is configured such that the end (612) of the plunger (204) is seated again against the distal end (508) of the dose sleeve (202) once the plunger (204) completes its movement by the first distance. In certain embodiments, a next dosage number that the user sees through the dose indicator window (108) is zero once the first dose of the medicament is delivered from the dispensing device (102).
[0068] Subsequent to delivery of the first dose from the dispensing device (102), the user needs to release the downward force exerted on the thumb pad (802) such that the unlocking device (210) moves back towards the proximal end (114) of the dispensing device (102). The movement of the unlocking device (210) towards the proximal end (114) also causes the stem portion (804) to move up towards the proximal end (114). Consequently, the first and second flexible pawls (712A-B) flex down. Further, the first and second flexible pawls (712A-B) are placed back in an engaged state with respect to another tooth of the ratchet (620).
[0069] FIG. 14 illustrates another cross-sectional view (1400) of the exemplary dispensing device (102) of FIG. 1 depicting the first and second flexible pawls (712A-B) when placed in an engaged state with respect to a fifth tooth (1402) of the ratchet (620) after the first dose is delivered from the dispensing device (102). Though the dose setting and delivering processes for subsequent doses such as a second dose, a third dose, a fourth dose, etc. are not explained in greater detail, it is to be understood that the dose setting and delivering processes are similar to the first dose setting and delivering process described previously.
[0070] For example, the dose-setting knob (106) is again rotated in the desired direction to set the second dose to be delivered, thus causing the dose sleeve (202) to move by a second distance. In one embodiment, the second distance by which the dose sleeve (202) moves corresponds to the set second dose. For example, in a particular scenario, if the second dose that is set for delivery is 112.5 IU, then the second distance by which the dose sleeve (202) moves towards the distal end (116) is 3 millimeters that corresponds to injecting 0.24 ml of the material into the user. In another scenario, if the second dose that is set of delivery is 150 IU, then the second distance by which the dose sleeve (202) moves towards the distal end (116) is 4 mm that corresponds to delivery of 0.32 ml of the material. Subsequent to setting of a desired second dose, the thumb pad (802) is depressed towards the distal end (116) of the dispensing device (102) such that the first and second flexible pawls (712A-B) are disengaged from the fifth tooth (1402) of the ratchet (620). Further, the plunger (204) moves by the second distance by which the dose sleeve (202) had moved earlier due to force exerted by the first elastic member (212) to release the set second dose from the dispensing device (102). Upon releasing the downward force exerted on the thumb pad (802), the first and second flexible pawls (712A-B) flex down and are placed back in an engaged state with respect to another tooth of the ratchet (620).
[0071] FIG. 15 illustrates yet another cross-sectional view (1500) of the exemplary dispensing device (102) of FIG. 1 depicting the dose sleeve (202) placed in an engaged state with respect to the cartridge (218) after a final dose is delivered from the dispensing device (102). In certain embodiments, the dispensing device (102) allows the user to set and to deliver variable doses for multiple injections such that the dose sleeve (202) is configured to move by a corresponding distance each time while a desired dose to be delivered is set. Once a final dose is set and is delivered from the dispensing device (102), the dose sleeve (202) is placed in the engaged state with respect to the cartridge (218). Consequently, the dose-setting knob (106) cannot be rotated further to set a new dose as a further movement of the dose sleeve (202) towards the distal end (116) is prevented by the presence of the cartridge (218). The inability to further rotate the dose-setting knob (106) indicates an end of life for the dispensing device (102).
[0072] In certain embodiments, as previously noted, the dispensing device (102) is configured to limit the maximum dose that can be set and be delivered in a single delivery. Additionally, the dispensing device (102) is configured to allow the user to set the final dose according to an amount of material that is left in the cartridge (218). To that end, the plunger (204) of the dispensing device (102) is provided with a final dose limiter and at least one layer of stoppers, as explained in greater detail with reference to FIG. 16.
[0073] FIG. 16 illustrates a front view (1600) of the plunger (204) of the exemplary dispensing device (102) of FIG. 1. In certain embodiments, the plunger (204) includes a final dose limiter (1602) and at least one layer of stoppers that are disposed on an outer surface (1604) of the cylindrical body portion (602) of the plunger (204). For example, FIG. 16 depicts the plunger (204) that includes three layers of stoppers including a first layer of stoppers (1606), a second layer of stoppers (1608), and a third layer of stoppers (1610). Further, each of the first layer (1606), the second layer (1608), and the third layer (1610) includes a plurality of stoppers that are helically arranged around the outer surface (1604) of the cylindrical body portion (602). In one embodiment, a total number of stopper layers to be disposed on the outer surface (1604) of the plunger (204) are selected based on a maximum dose that is to be delivered at once.
[0074] For example, in a particular scenario, a volume of the cartridge (218) is 3 ml, the cartridge (218) is filled with 1.92 ml of a material, and a maximum dose that is set to be delivered at once from the dispensing device (102) is 0.64 ml. In this example, a total number of stopper layers that are to be disposed on the plunger (204) are 3. Until completing delivery of a first volume range (e.g., a first 0.64 ml) of a material from the dispensing device (102), a set of stoppers in a first layer (1606) ensure the user cannot set a dose that is more than the set maximum dose of 0.64 ml at once. One of the stoppers in the first layer (1606) is placed in a locked state (1902) (shown in FIG. 19) with respect to the protrusion (412) disposed at the distal end (414) of the dose-setting knob (106) and prevents the user from setting the dose above 0.64 ml, as explained in detail in subsequent paragraphs.
[0075] In a particular scenario, the user attempts to set a dose above 0.64 ml post delivery of the first 0.64 ml of the material from the dispensing device (102). In this scenario, a corresponding rotation of the dose setting knob (106) causes one of the stoppers in a second layer (1608) to be placed in the locked state (1902) with respect to the protrusion (412) to prevent the user from setting a dose that is more than the set maximum dose. Similarly, after the first 1.28 ml of the material is delivered and when the user attempts to set a dose above 0.64 ml, one of the stoppers in a third layer (1610) is similarly placed in the locked state (1902) with respect to the protrusion (412). Thus, for the given example of the cartridge (218) that is filled with 1.92 ml of the material, and where the set maximum dose to be dispensed at once is 0.64 ml, the total number of stopper layers to be disposed on the plunger (204) is 3.
[0076] In another example, a volume of the cartridge (218) is 3 ml, the cartridge (218) is filled with 1.92 ml, and a maximum dose that can be delivered at once from the dispensing device (102) is 0.96 ml. In this example, a total number of stopper layers that are to be disposed on the outer surface (1604) of the plunger (204) is 2. Similarly, it is to be understood that the total number of stopper layers to be disposed on the plunger (204) are selected based on the maximum dose that is to be delivered at once.
[0077] In certain embodiments, a number of stoppers in each corresponding stopper layer is same and is selected based on a desired dose resolution. Throughout description of various embodiments herein, the term ‘dose resolution’ refers to a minimum dose that can be set and be delivered at once from the dispensing device (102). For example, in one scenario, the cartridge (218) is filled with 1.92 ml of a material, a maximum dose that can be delivered at once is 0.64 ml, and a dose resolution of the dispensing device (102) is 0.16 ml. In this example, the total number of stopper layers that need to be disposed on the plunger (204) are three and each of the layers has four stoppers. Thus, a manufacturer of the dispensing device (102) can configure the dispensing device (102) to dispense a desired maximum dose at once by selecting a suitable number of stopper layers. Similarly, the manufacturer can configure the dose resolution of the dispensing device (102) by selecting and disposing a suitable number of stoppers in each of the stopper layers.
[0078] FIG. 16 depicts a configuration of the plunger (204) that is used in one embodiment to limit a maximum dose, for example 300 IU, which can be set and be dispensed at once from the dispensing device (102). In addition, a dose resolution of the dispensing device (102) is 37.5 IU, a volume of the cartridge (218) is 3 ml, and the cartridge (218) is filled with 2 ml of a material. For this particular example, a mechanism by which a user is prevented from setting a dose above the set maximum dose of 300 IU at once is explained in detail in subsequent paragraphs with reference to FIGS. 16 and 17. However, it is to be understood that the maximum dose that can be set at once and the dose resolution can be tailored according to a specific requirement associated with the dispensing device (102) by selecting a suitable number of stopper layers and a suitable number of stoppers in each corresponding layer of the plunger (204), as noted previously.
[0079] In one embodiment, the plunger (204) includes the first layer of stoppers (1606) that has eight stoppers labelled from (1606A) to (1606H) as depicted in FIGS. 16 and 17. A set of four stoppers (1606A, 1606B, 1606C, and 1606H) is depicted in FIG. 16 and another set of four stoppers (1606D, 1606E, 1606F, and 1606G) is depicted in FIG. 17. Similarly the second layer of stoppers (1608) has eight stoppers labelled from (1608A) to (1608H), and the third layer of stoppers (1610) has eight stoppers labelled from (1610A) to (1610H) that are depicted in FIGS. 16 and 17. FIG. 17 illustrates an example of a label (1700) affixed on the cylindrical body portion (602) of the plunger (204). In one embodiment, the label (1700) includes a plurality of dosage numbers that are helically printed in a selected international unit of volume. Alternatively, the plurality of dosage numbers can be helically printed in any units specific to a material to be delivered and as defined by a manufacturer of the dispensing device (102) or the material.
[0080] In one embodiment, the label (1700) includes a corresponding hole (1702) for each stopper in the first layer (1606), the second layer (1608), and the third layer (1610). As depicted in FIG. 17, each of the stoppers (1606A-H, 1608A-H, and 1610A-H) projects out through the corresponding hole (1702) of the label (1700) when the label (1700) is affixed on the cylindrical body portion (602) of the plunger (204). In an alternative embodiment, the plurality of dosage numbers can be printed directly on the cylindrical body portion (602) of the plunger (204) instead of affixing the label (1700) on the cylindrical body portion (602).
[0081] In certain embodiments, the stoppers (1606A-H, 1608A-H, and 1610A-H) are helically arranged on the cylindrical body portion (602) such that each stopper in the first layer (1606) and corresponding stoppers in the second and third layers (1608 and 1610) lie along a common imaginary axis that is horizontal to a vertical axis of the plunger (204). For example, the stopper (1606A) lies in a common imaginary axis with respect to a corresponding stopper (1608A) in the second layer (1608) and a corresponding stopper (1610A) in the third layer (1610).
[0082] Further, a distance between each stopper in the first layer (1606) and a corresponding stopper in the second layer (1608) is a fixed designated distance. For example, a distance between the stopper (1606A) and the stopper (1608A) is same as a distance between the stopper (1606B) and the stopper (1608B). Similarly, a distance between each stopper in the second layer (1608) and a corresponding stopper in the third layer (1610) is also same as the fixed designated distance. This fixed designated distance is configured by a manufacturer of the dispensing device (102).
[0083] In one embodiment, a distance between a selected stopper in the first layer (1606) and a subsequent stopper in the first layer (1606) is a fixed desired distance. For example, a distance between the stopper (1606A) and the stopper (1606B) is same as a distance between the stopper (1606B) and the stopper (1606C). Similarly, a distance between any two subsequent stoppers in the second and third layers (1608 and 1610) is also same as the fixed desired distance.
[0084] In certain embodiments, the protrusion (412) of the dose-setting knob (106) placed at a position (1703) below the stopper (1606A) in the first layer (1606) before setting the first dose using the dose-setting knob (106).
[0085] FIG. 18 illustrates a cross sectional view of an arrangement of the dose-setting knob (106) and the plunger (204) depicting the protrusion (412) placed below the stopper (1606A) in an unlocked state (1802) before setting the first dose. Referring back to FIG. 17, when the protrusion (412) is placed below the stopper (1606A) in the unlocked state (1802), a user perceives a dosage number (1704) that corresponds to a zero set dose through the dose indicator window (108) before setting the first dose.
[0086] In one embodiment, a user can rotate the dose-setting knob (106) such that the user perceives dosage numbers through the dose indicator window (108) in an incremental order as per a selected dose resolution. In the current example, the selected resolution is 37.5 IU. Hence, the user perceives a dosage number (1706) that corresponds to 37.5 IU as a next settable dose through the dose indicator window (108) when the user rotates the dose-setting knob (106) for setting the first dose. The dispensing device (102) is configured such that the user cannot select a dose in between 0 to 37. 5 IU. Moreover, the user perceives a dosage number (1708) that corresponds to 75.0 IU as a next settable dose through the dose indicator window (108) when the user further rotates the dose-setting knob (106). Similarly, it is to be understood that the user can increment the dose to be delivered in an incremental order of 37.5 IU by rotating the dose-setting knob (106) in a desired direction, for example in the clockwise direction.
[0087] The user can keep rotating the dose-setting knob (106) in the desired direction until the user perceives the maximum dose (e.g., 300 IU) that can be set at once through the dose indicator window (108). After that, the user cannot rotate the dose-setting knob (106) further. For example, the user attempts to set 337.5 IU as the first dose. In this example, the protrusion (412) is initially placed in the unlocked state (1802) at the position (1703) below the stopper (1606A) in the first layer (1606). As the user increments the dose from 0 IU to 37.5 IU in the process of setting 337.5 IU as the first dose, the protrusion (412) rotates in a circular path (1804) as shown in FIG. 18 along with the dose-setting knob (106). Consequently, the protrusion (412) moves away from the stopper (1606A) and is approximately placed at a position (1705) below the stopper (1606B).
[0088] As the user further increments the dose from 37.5 IU to 75.0 IU during the process of setting 337.5 IU as the first dose, the protrusion (412) again rotates in the circular path (1804) and is placed at a position (1707) below the stopper (1606C). Similarly, it is to be understood that, as the user increments the dose from 75.0 IU to 262.5 IU, the protrusion (412) is placed approximately below the stopper (1606G). As the user, further increments the dose from 262.5 IU to 300 IU, the protrusion (412) completes a partial revolution in the circular path (1804) and is placed in a locked state (1902), as shown in FIG. 19 with respect to the stopper (1606H). When the user attempts to increase the dose from 300 IU to 337.5 IU by rotating the dose-setting knob (106), the stopper (1606H) prevents further rotational motion of the dose-setting knob (106) as the protrusion (412) is placed in the locked state (1902) with respect to the stopper (1606H). Thus, the user is prevented from setting the dose above 300 IU at once.
[0089] Once the first dose of 300 IU is set for delivery, as described previously, the thumb pad (802) of the unlocking device (210) needs to be depressed. As a result, the first and second flexible pawls (712A-B) disposed in an engaged state with respect to the first tooth (1008) of the ratchet (620) are disengaged. Consequently, the plunger (204) moves by the same distance by which the dose sleeve (202) had moved earlier while setting the first dose of 300 IU. Once the set first dose of 300 IU is delivered from the dispensing device (102), a next dosage number that the user sees through the dose indicator window (108) is a zero dosage number (1710) due to downward movement of the plunger (204) towards the distal end (116) of the dispensing device (102). The downward movement of the plunger (204) also causes the protrusion (412) to be placed below the stopper (1608H) in the second layer (1608).
[0090] In another example, the user first attempts to deliver 150 IU as a first dose and further attempts to set 337.5 IU as a second dose. In this example, the user first rotates the dose-setting knob (106) in the desired direction until the user sees a dosage number (1712) as 150 IU through the dose indicator window (108). The rotation of the dose-setting knob (106) causes the protrusion (412) placed at the position (1703) below the stopper (1606A) to move away and be placed approximately at a position (1709) below the stopper (1606E). Then, when the user depresses the thumb pad (802), the plunger (204) moves towards the distal end (116) by a designated distance to inject the set first dose of 150 IU into the user. The downward movement of the plunger (204) causes the stopper (1606E) to come down to a position (1714) (shown using a square box in FIG. 17) and to be placed in the unlocked state (1802) with respect to the protrusion (412). In one embodiment, a next dosage number (1716) that the user sees through the dose indicator window (108) is zero once the first dose of 150 IU of the medicament is injected into the user.
[0091] After the first dose of 150 IU is delivered from the dispensing device (102), the user may attempt to set 337.5 IU as the second dose by rotating the dose-setting knob (106). During such an attempt, the protrusion (412) placed at the position (1709) below the stopper (1606E) moves away in the circular path (1804) and engages with the stopper (1606D) in the locked state (1902) when the user finishes setting the medicament dose of 300 IU. When the user further attempts to increment the dose from 300 IU to 337.5 IU by rotating the dose-setting knob (106), the stopper (1606D) prevents further rotational motion of the dose-setting knob (106) as the protrusion (412) is placed in the locked state (1902) with respect to the stopper (1606D). Thus, the plurality of stoppers (1606A-H, 1608A-H, and 1610A-H) disposed on the cylindrical body portion (602) of the plunger (204) prevents the user from setting a dose that is more than 300 IU at once.
[0092] In certain embodiments, the final dose limiter (1602) that is disposed on the cylindrical body portion (602) of the plunger (204) allows the user to set a final dose according to an amount of a material that is left in the cartridge (218). In one embodiment, a length of the final dose limiter (1602) is comparatively more than a corresponding length associated with each of the stoppers (1606A-H, 1608A-H, and 1610A-H). For example, in one scenario, the dispensing device may have already delivered 1.6 ml of the material (102) and a remaining volume of the material in the cartridge (218) may be 0.4 ml that is equivalent to 187.5 IU. In this example, the user may attempt to set 300 IU as a final dose that is equivalent to delivery of 0.64 ml. Such attempts of the user need to be prevented, as the remaining volume (e.g., 0.4 ml) of the material in the cartridge (218) is less than the dose (e.g., 0.64 ml) that the user intends to set and deliver. To that end, the final dose limiter (1602) is provided on the cylindrical body portion (602) of the plunger (204).
[0093] In certain embodiments, as the volume of the material in the cartridge (218) reduces, the protrusion (412) is configured to proportionately move and to reach closer to the final dose limiter (1602). For the previously mentioned example, a position of the protrusion (412) is configured such that the protrusion (412) is placed in the unlocked state (1802) below the stopper (1610E) when 1.6 ml of the material has already been delivered from the dispensing device (102). When the user increments the dose from 0 IU to 150.0 IU while attempting to set 300 IU as the final dose, the protrusion (412) rotates in the circular path (1804) and is placed below the stopper (1610A).
[0094] Subsequently, the protrusion (412) further rotates in the circular path (1804) and engages with the final dose limiter (1602) when the user increments the dose from 150.0 IU to 187.5 IU that is equivalent to the remaining dose of 0.4 ml in the cartridge (218). At this stage, when the user attempts to further increment the dose from 187.5 IU, the final dose limiter (1602) acts as an obstacle in the circular path (1804) of the protrusion (412) and prevents the protrusion (412) from moving further in the circular path (1804). Therefore, the user cannot rotate the dose-setting knob (106) further to increment the dose beyond 187.5 IU, which is equivalent to the dose remaining in the cartridge (218).
[0095] The exemplary dispensing device (102) described herein throughout various embodiments allows a user to set a desired amount of material for dose delivery and to vary a dose according to a specific need of the user. Further, the dispensing device (102) is capable of accurately delivering the set desired dose by a pressing action of the thumb pad (802) towards the distal end (116) of the dispensing device (102). The pressing action of the thumb pad (802) releases the plunger (204) from a locked position to an unlocked position to enable the movement of the plunger (204) due to the force exerted by the first elastic member (212) and to release the set desired dose. The locking device (208) ensures the plunger (204) is placed in the locked position while setting a dose, and hence, the plunger (204) is not disturbed during a dose-setting process and thereby any accidental delivery of dose during the dose-setting process is circumvented.
[0096] Further, the thumb pad (802) is configured to not protrude out of the proximal end (114) of the dispensing device (102) during the dose-setting process. Hence, the user can conveniently press the thumb pad (802) using a single arm once a desired dose is set for delivery. Moreover, the dispensing device (102) provides a variety of safety features to the user. The plunger (204) along with the dose-setting knob (106) prevents the user from setting and delivering a dose that is more than a set threshold limit at once. Further, the final dose limiter (1602) of the plunger (204) allows the user to set the final dose according to an amount of the material remaining in the cartridge (218). Hence, the dispensing device (102) ensures that the user is injected with an appropriate amount of material during the final dose delivery.
[0097] Although specific features of various embodiments of the present systems and methods may be shown in and/or described with respect to some drawings and not in others, this is for convenience only. It is to be understood that the described features, structures, and/or characteristics may be combined and/or used interchangeably in any suitable manner in the various embodiments shown in the different figures.
[0098] While only certain features of the present systems and methods have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the claimed invention.