DESC:Field of Invention
The invention generally relates to a hand assembly. The invention more particularly relates to a hand assembly for the prosthetic hand application. Even more particularly the present invention relates to the assembly and mechanisms of hand for controlling movement of each digit.
Background of Invention:
Robotic hands or artificial hands are widely used for industrial or prosthetic applications. Typically, robotic hands comprise of plurality of movable fingers or digits or tactile members, wherein each of the fingers/ digits/ tactile members have dedicated mechanisms for controlling their movements.
For prosthetic applications, it is desirable that artificial hands have anthropomorphic properties i.e., the artificial hand should have physical dimensions, including length and weight analogous to a human hand. Also, it is desirable that the artificial hand has dexterity and aesthetic appeal. Further, human hand has an average weight of 400 grams. Accordingly, taking into consideration these factors, components or mechanism that can be accommodated/housed in artificial hands are limited. For industrial applications such requirements/restrictions are generally not applicable. However, dedicated mechanisms for controlling movement of each digit makes robotic hands bulky and expensive.
In view of the above, there is a need in the art for robotic hands addressing at-least aforementioned problems.
Objects of the Invention
The primary object of the present invention is to provide a hand assembly.
Yet another object of the present invention is to provide a hand assembly for the effectively controlling movement of each digit.
Still another object of the present invention is to provide a hand assembly comprising of Frame, Plurality of knuckle members, Plurality of digits characterized into that a proximal phalanx and a distal phalanx, a top casing and a bottom casing characterized to enclose the said frame and components thereon within the said top casing and bottom casing.
Another object of the present invention is to provide a hand assembly that emulates a human hand whereby the frame corresponds to a palm, and the plurality of digits correspond to four fingers (i.e. index, middle, ring, and little) and thumb of the hand.
Summary of the Invention:

Accordingly, the present invention provides a hand assembly comprising a Frame (110), Plurality of knuckle members (120), Plurality of digits (130) characterized into that a proximal phalanx (132) and a distal phalanx (134), a top casing (210) and a bottom casing (220) characterized to enclose the said frame (110) and components thereon within the said top casing (210) and bottom casing (220), Plurality of link assembly (10) characterized into that a first linkage (12) and a second linkage (14), at least one dedicated drive mechanism (20), at least one common drive mechanism (30), a wrist mechanism (40) characterized to rotate said hand assembly about an axis perpendicular to the wrist assembly. Knuckle members (120) characterized to be coupled with frame (110).
Detailed description of the invention:

The present invention is directed towards a hand assembly which can be used for robotic/automated applications or as a prosthetic device. The hand assembly is lightweight and requires minimum number of components to perform various functions and/ or actions.
Various embodiments of a hand assembly 100 are shown through figure 1 through 6. The hand assembly comprises a frame 110, plurality of knuckle members 120, and plurality of digits 130. In an example embodiment as illustrated, the hand assembly emulates a human hand whereby the frame corresponds to a palm, and the plurality of digits correspond to four fingers (i.e. index, middle, ring, and little) and thumb of the hand. Accordingly, the four fingers are provided on top side of the frame, whereas the thumb is provided adjacent to bottom side of the frame. As shown in figure 1, the hand assembly comprises a top casing 210 and a bottom casing 220 so as to enclose the frame and components thereon within the casing. The top casing and bottom casing protect components contained on the frame of the hand assembly from damage that may be caused by external factors. The digits are also enclosed in a casing which correspond withs shape of fingers. Further, the casings have a rubber grip to increase friction.
Further, the hand assembly comprises a link assembly 10 for each digit, and at-least one dedicated drive mechanism 20 for each link assembly and at-least one common drive mechanism 30 for at-least two link assemblies. Further, the hand assembly comprises a wrist mechanism 40 which enables the hand assembly to be rotatable about an axis perpendicular to the wrist assembly.
The knuckle members can be seen in figure 3 which illustrates the hand assembly without the digits. As shown, the knuckle members are coupled to the frame. In an embodiment, each knuckle member is fixed with the frame and each digit is pivotally coupled with the knuckle member. Accordingly, each digit is capable of pivotal movement about the frame/knuckle member, whereby the digits are configured to move individually, and at-least two digits are configured to move simultaneously enabling the hand assembly to perform multiple functions and/or actions.
In an embodiment, as shown through the figures, each digit has a proximal phalanx 132 and a distal phalanx 134. The proximal phalanx is pivotally coupled with the knuckle member and the distal phalanx is pivotally coupled with the proximal phalanx. Accordingly, the proximal phalanx moves pivotally about the frame/knuckle member and the distal phalanx moves pivotally about the proximal phalanx. In an embodiment, the link assembly controls movement of the digits.
For reference, the link assembly of the index digit is illustrated in figure 4. The link assembly comprises a first linkage 12 and a second linkage 14. In an embodiment of the invention, the second linkage comprises two parallel links for even load distribution. The first linkage is connected with the drive mechanism at one end, and with the proximal phalanx at the other end. The second linkage is pivotally mounted on the knuckle member and is coupled with the distal phalanx. Movement of the first linkage causes the proximal phalanx and the second linkage to move pivotally about the frame, whereby movement of the second linkage causes the distal phalanx to move pivotally about the proximal phalanx. The drive mechanism as shown in the figure is connected with the first linkage. As shown, a dedicated drive mechanism is provided for the thumb digit and a dedicated drive mechanism is provided for the index digit, and a common drive mechanism is provided for the remaining digits. The drive mechanism comprises a linear motor 22 with an output shaft 24, 34. Alternately, the drive mechanism can comprise a hydraulic drive and an output shaft. In an embodiment, the output shaft 24 of the dedicated drive mechanism is configured to connect with at-least one first linkage of the link assembly whereas the output shaft 34 of the common drive mechanism is configured to connect with the first linkage of plurality of link assemblies. Upon actuation of the drive mechanism, the drive mechanism moves the output shaft between an extended position and a retracted position. In the retracted position, the output shaft pulls the first linkage causing the proximal phalanx to move pivotally about the knuckle member whereby the proximal phalanx pivots inward. The movement of the proximal phalanx leads to corresponding movement of the second linkage which pulls the distal phalanx which pivots about the proximal phalanx. In a similar manner, when the shaft moves to the extended position the first linkage causes the proximal phalanx to move pivotally about the knuckle member whereby the proximal phalanx pivots outward. The movement of the proximal phalanx leads to corresponding movement of the second linkage which pushes the distal phalanx which pivots about the proximal phalanx.
Further, as shown, by way of example, the output shaft of the common drive mechanism interconnects the link assemblies of the middle, ring, and little digits such that each of these digits move simultaneously. Accordingly, upon actuation of the common drive mechanism, the common drive mechanism moves all the link assemblies causing the proximal phalanges and distal phalanges of the middle, ring, and little digits to move simultaneously.
Further, as shown in figure 5, each output shaft comprises at-least two reflecting regions – first reflecting region R1 and second reflecting region R2 which are spaced apart. The first reflecting region is provided adjacent to leading end of the output shaft, and the second reflecting region is provided adjacent to trailing end of the output shaft. Each output shaft is disposed between parallel walls having two apertures 10 with an infrared sensor (not shown) provided adjacent to the apertures (50) When the drive mechanism is operated, and the output shaft is extended and retracted, the infrared sensor emits a light beam which is reflected back by any of the reflecting regions. The reflecting regions align with the apertures (50) when the drive shaft is in the extended position or retracted position. Upon receiving the reflected light beam, operation of the drive mechanism is cut-off so as to prevent further operation of the drive mechanism once the output shaft is in the extend position or retracted position to prevent further extension or retraction of the drive shaft and thereby the digits. Also, overrunning, overheating or malfunctioning of the drive mechanism and any components of the hand assembly is prevented.
Further, a force sensor is provided in tip of each distal phalanx. The force sensor is configured to determine/monitor force experienced by the distal phalanx while gripping/holding objects. In case, the sensor determines that the force exerted is higher than a predetermined threshold value, operation of the drive mechanism is controlled. Further, a current limiting sensor is provided in each drive mechanism of the hand assembly. Each current limiting sensor prevents the corresponding drive mechanism from overrunning, thereby preventing any overheating or malfunctioning of the drive mechanism and any components of the hand assembly.
Figure 6 illustrates various positions or actions or functions the hand assembly of the present invention is configured to perform. First position is illustrated in figure 6A, whereby the index finger is extended whereas the remaining fingers and thumb is folded. Second position is illustrated in figure 6B whereby the index finger and thumb is folded whereas the remaining fingers are extended. Third position is illustrated in figure 6C whereby all the fingers and thumb are folded. Fourth position is illustrated in figure 6D whereby all the fingers are relaxed. Since the link assemblies of the middle, ring, and little digits are interconnected, the middle, ring, and little digits move simultaneously enabling the hand assembly to perform the aforesaid functions with minimum drive mechanisms which otherwise would require dedicated mechanisms for each digit. This is advantageous from a cost as well as a weight perspective especially in cases where the hand assembly is adapted to be used as a prosthetic device. In this regard, the hand assembly has weight less than 400 grams, and is capable of handling objects which are light weight as well as heavy weight.
Advantageously, hand assembly of the present invention emulates a human hand and is capable of performing multiple functions with minimum components, thereby maintaining the weight requirements for at-east prosthetic applications. Also, the hand assembly has aesthetic features. Further, the hand assembly is easy to maintain, as various components can be easily removed and installed.
The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since the modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to the person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.
Brief description of the drawing:
Figure 1 shows a hand assembly in accordance with an embodiment of the invention.
Figure 2 shows a hand assembly in accordance with an embodiment of the invention.
Figure 3 shows the hand assembly without digits in accordance with an embodiment of the invention.
Figure 4 shows a side view of the hand assembly in accordance with an embodiment of the invention.
Figure 5 shows an output shaft of the hand assembly in accordance with an embodiment of the invention.
Figure 6 illustrates the hand assembly in various positions.
Following table describes the legends used in the drawings

Sr No Legend
100 Hand Assembly
110 Frame
120 Knuckle members
130 Plurality of digits
132 Proximal Phalanx
134 Distal Phalanx
210 Top casing
220 Bottom casing
10 Link Assembly
20 Dedicated drive mechanism
30 Common drive mechanism
40 Wrist mechanism
132 Proximal Phalanx
134 Distal Phalanx
12 First Linkage
14 Second Linkage
24 Dedicated drive output shaft
34 Common drive output shaft
22 Linear Motor
R1 First Reflecting Reflex
R2 Second Reflecting Reflex
50 Apertures

Detailed description of drawing:

Figure 1 further explains the hand assembly comprises a top casing 210 and a bottom casing 220 so as to enclose the frame and components thereon within the casing. The top casing and bottom casing protect components contained on the frame of the hand assembly from damage that may be caused by external factors. The digits are also enclosed in a casing which correspond withs shape of fingers. Further, the casings have a rubber grip to increase friction.
Figure 2 further explains a hand assembly comprises a link assembly 10 for each digit, and at-least one dedicated drive mechanism 20 for each link assembly and at-least one common drive mechanism 30 for at-least two link assemblies. Further, the hand assembly comprises a wrist mechanism 40 which enables the hand assembly to be rotatable about an axis perpendicular to the wrist assembly.
Figure 3 illustrates the knuckle members the hand assembly without the digits. As shown, the knuckle members are coupled to the frame. In an embodiment, each knuckle member is fixed with the frame and each digit is pivotally coupled with the knuckle member. Accordingly, each digit is capable of pivotal movement about the frame/knuckle member, whereby the digits are configured to move individually, and at-least two digits are configured to move simultaneously enabling the hand assembly to perform multiple functions and/or actions.
In an embodiment, as shown through the figures, each digit has a proximal phalanx 132 and a distal phalanx 134. The proximal phalanx is pivotally coupled with the knuckle member and the distal phalanx is pivotally coupled with the proximal phalanx. Accordingly, the proximal phalanx moves pivotally about the frame/knuckle member and the distal phalanx moves pivotally about the proximal phalanx. In an embodiment, the link assembly controls movement of the digits.
Figure 4 further illustrates the link assembly of the index digit. The link assembly comprises a first linkage (12) and a second linkage (14). In an embodiment of the invention, the second linkage comprises two parallel links for even load distribution. The first linkage is connected with the drive mechanism at one end, and with the proximal phalanx at the other end. The second linkage is pivotally mounted on the knuckle member and is coupled with the distal phalanx. Movement of the first linkage causes the proximal phalanx and the second linkage to move pivotally about the frame, whereby movement of the second linkage causes the distal phalanx to move pivotally about the proximal phalanx. The drive mechanism as shown in the figure is connected with the first linkage. As shown, a dedicated drive mechanism is provided for the thumb digit and a dedicated drive mechanism is provided for the index digit, and a common drive mechanism is provided for the remaining digits. The drive mechanism comprises a linear motor (22) with an output shaft (24, 34). Alternately, the drive mechanism can comprise a hydraulic drive and an output shaft. In an embodiment, the output shaft 24 of the dedicated drive mechanism is configured to connect with at-least one first linkage of the link assembly whereas the output shaft 34 of the common drive mechanism is configured to connect with the first linkage of plurality of link assemblies. Upon actuation of the drive mechanism, the drive mechanism moves the output shaft between an extended position and a retracted position. In the retracted position, the output shaft pulls the first linkage causing the proximal phalanx to move pivotally about the knuckle member whereby the proximal phalanx pivots inward. The movement of the proximal phalanx leads to corresponding movement of the second linkage which pulls the distal phalanx which pivots about the proximal phalanx. In a similar manner, when the shaft moves to the extended position the first linkage causes the proximal phalanx to move pivotally about the knuckle member whereby the proximal phalanx pivots outward. The movement of the proximal phalanx leads to corresponding movement of the second linkage which pushes the distal phalanx which pivots about the proximal phalanx.
Further, as shown, by way of example, the output shaft of the common drive mechanism interconnects the link assemblies of the middle, ring, and little digits such that each of these digits move simultaneously. Accordingly, upon actuation of the common drive mechanism, the common drive mechanism moves all the link assemblies causing the proximal phalanges and distal phalanges of the middle, ring, and little digits to move simultaneously.
Figure 5 further explains each output shaft comprises at-least two reflecting regions, a first reflecting region R1 and second reflecting region R2 which are spaced apart. The first reflecting region is provided adjacent to leading end of the output shaft, and the second reflecting region is provided adjacent to trailing end of the output shaft. Each output shaft is disposed between parallel walls having two apertures (50) with an infrared sensor (not shown) provided adjacent to the apertures (50). When the drive mechanism is operated, and the output shaft is extended and retracted, the infrared sensor emits a light beam which is reflected back by any of the reflecting regions. The reflecting regions align with the apertures (50) when the drive shaft is in the extended position or retracted position. Upon receiving the reflected light beam, operation of the drive mechanism is cut-off so as to prevent further operation of the drive mechanism once the output shaft is in the extend position or retracted position to prevent further extension or retraction of the drive shaft and thereby the digits. Also, overrunning, overheating or malfunctioning of the drive mechanism and any components of the hand assembly is prevented.
Further, a force sensor is provided in tip of each distal phalanx. The force sensor is configured to determine/monitor force experienced by the distal phalanx while gripping/holding objects. In case, the sensor determines that the force exerted is higher than a predetermined threshold value, operation of the drive mechanism is controlled. Further, a current limiting sensor is provided in each drive mechanism of the hand assembly. Each current limiting sensor prevents the corresponding drive mechanism from overrunning, thereby preventing any overheating or malfunctioning of the drive mechanism and any components of the hand assembly.

Figure 6 illustrates various positions or actions or functions the hand assembly of the present invention is configured to perform. First position is illustrated in figure 6A, whereby the index finger is extended whereas the remaining fingers and thumb is folded. Second position is illustrated in figure 6B whereby the index finger and thumb are folded whereas the remaining fingers are extended. Third position is illustrated in figure 6C whereby all the fingers and thumb are folded. Fourth position is illustrated in figure 6D whereby all the fingers are relaxed. Since the link assemblies of the middle, ring, and little digits are interconnected, the middle, ring, and little digits move simultaneously enabling the hand assembly to perform the aforesaid functions with minimum drive mechanisms which otherwise would require dedicated mechanisms for each digit. This is advantageous from a cost as well as a weight perspective especially in cases where the hand assembly is adapted to be used as a prosthetic device. In this regard, the hand assembly has weight less than 400 grams, and is capable of handling objects which are light weight as well as heavy weight
,CLAIMS:We claim,
1. A Hand Assembly comprising:
- A Frame (110), Plurality of digits (130) characterized into that a proximal phalanx (132) and a distal phalanx (134), a top casing (210) and a bottom casing (220) characterized to enclose the said frame (110) and components thereon within the said top casing (210) and bottom casing (220);
- Plurality of link assembly (10) characterized into that a first linkage (12) and a second linkage (14), at least one dedicated drive mechanism (20), at least one common drive mechanism (30), a wrist mechanism (40) characterized to rotate said hand assembly about an axis perpendicular to the wrist assembly.
- Knuckle members (120) characterized to be coupled with frame (110).
2. A hand assembly as claimed in claim 1; wherein, said plurality of link assembly (10) for said plurality of digits (130) are coupled with at least on dedicated drive mechanism (20) and at least one common drive mechanism (30) characterized into that a linear motor (22) with an output shaft (24, 34) and alternatively a hydraulic drive and an output shaft (24,34), wherein the output shaft (24) of the dedicated drive mechanism (20) is configured to be connected with at-least one first linkage (12) of the link assembly (10) whereas the output shaft (34) of the common drive mechanism (30) is configured to be connected with the first linkage (12) of plurality of link assembly (10).
3. A hand assembly as claimed in claim 2, wherein the drive mechanism (20) comprises of current limiting sensor characterized to prevents the corresponding drive mechanism (20,30) from overrunning, thereby preventing any overheating or malfunctioning of the drive mechanism (20,30) and any components of said hand assembly (100).
4. A hand assembly as claimed in claim 1; wherein, said Knuckle members (120) characterized to be fixed with frame (110) and plurality of digits (130) are pivotally coupled with the said knuckle member (120) in a manner that plurality of digits (130) is capable of pivotal movement about the said frame (110) and knuckle member (120), whereby the plurality of digits (130) is configured to move individually, and at-least two digits are configured to move simultaneously.
5. A hand assembly as claimed in claim 1; wherein, said plurality of digits (130) comprises of a proximal phalanx (132) and a distal phalanx (134) and are arranged in a manner that said proximal phalanx (132) is pivotally coupled with the knuckle member (120) and said distal phalanx (134) is pivotally coupled with the proximal phalanx (132).
6. A hand assembly as claimed in claim 4; wherein proximal phalanx (132) moves pivotally about the knuckle member (120) and the distal phalanx (134) moves pivotally about the proximal phalanx (132).
7. A hand assembly as claimed in claim 1, wherein second linkage (14) comprises two parallel links characterized for even load distribution whereas the first linkage (12) is connected with the drive mechanism (20,30) at one end and with the proximal phalanx (132) at the other end.
8. A hand assembly as claimed in claim 4; wherein said distal phalanx (134) comprises of a force feedback sensor characterized to determine the force exerted at the tip of distal phalanx (134) while gripping and holding of objects in a manner that force exerted is higher than a predetermined threshold value, operation of the said drive mechanism (20,30) is controlled stopped.
9. A hand assembly as claimed in claim 1, wherein, common drive mechanism (30) moves the output shaft (34) between an extended position and a retracted position in a manner that the output shaft (34) pulls the said first linkage (12) causing the proximal phalanx (132) to move pivotally about the said knuckle member (120) whereby the proximal phalanx (132) pivots inward which in turn leads to corresponding movement of the second linkage (14) which pulls the distal phalanx (134) which pivots about the proximal phalanx (132).
10. A hand assembly as claimed in claim 2, wherein the said output shaft (34) is disposed between parallel walls (14) having two apertures (50) with an infrared sensor, said output shaft (34) comprises of at-least two reflecting regions namely a first reflecting region (R1) characterized to be adjacent to leading end of the output shaft (34) and second reflecting region (R2) characterized to be adjacent to trailing end of the output shaft (34).
11. A hand assembly as claimed in claim 1; wherein said drive mechanism (20,30) comprising of infrared sensor which emits light beam to be reflected back by at least one reflecting region (R1, R2); while the extension or retraction of the output shaft (24,34), said reflecting region (R1, R2) align with aperture (50) and upon receiving reflected light beam from reflecting region (R1, R2) said drive mechanism (20,30) stops in a manner that output shaft (24,34) is prevented from further extension and retraction.

Dated this 15th Day of May 2021