FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A SCREW JACK, AN OPERATING MECHANISM FOR THE SCREW
JACK AND A METHOD THEREOF”
Name and Address of the Applicant: TATA MOTORS LIMITED; Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India.
Nationality: Indian
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.

TECHNICAL FIELD
[001] Present disclosure generally relates to a field of mechanical lifting devices. Particularly, but not exclusively, the present disclosure, relates to a mechanism for a screw jack for lifting a vehicle. Further, embodiments discloses a method of operating the screw jack with reduced effort and time without changing a position of a handle with respect to a nut hole of the screw jack.
BACKGROUND OF THE DISCLOSURE
[002] Generally, a jackscrew or a jack assembly is a device used as a lifting element to lift an automobile during breakdown conditions with minimum human efforts. Typically, jacks are used to lift a vehicle for changing wheels and repairing other vehicle parts, which are arranged beneath the vehicle. The jack assemblies may be classified based on method of operation, and broad classification may include a mechanical jack assembly, and/or a hydraulic jack assembly, a scissor jack assembly etc.
[003] Conventionally, the mechanical jack assembly broadly comprises a lead screw disposed within a nut having internal threads. The nut may be rotated in a clockwise or in an anti-clockwise direction by an operator. For the rotation of the nut, a handle is engaged with the nut by positioning the handle within one hole of a plurality of holes defined circumferentially on the nut. The handle is then rotated by the operator to rotate the nut in the required direction. After rotation of the nut by an angle, the handle is removed from the hole and placed in a subsequent hole to rotate the nut. This operation of the handle is to be repeated multiple times for one full rotation of the nut. Further, multiple such operations of the handle are required to achieve lifting or lowering of the jack assembly. This rotation of the nut causes the lead screw to be raised or lowered about the internal threads of the nut. This process is continued until the lead screw is lifted to a required height. The continuous operation of placing the handle into each hole of the plurality of holes requires a lot of effort which causes fatigue to the operator due to prolonged operation. Further, as the jack assembly must be initially positioned beneath the vehicle, the operator must reach underneath the vehicle to operate the handle. This is uncomfortable and may compromise safety of the operator, as he/she is prone to accidents in case of operation failure of the jack.

[004] The present disclosure is directed to overcome one or more limitations stated above or other such limitations associated with the prior art.
SUMMARY OF THE DISCLOSURE
[005] One or more shortcomings of conventional systems are overcome, and additional advantages are provided through a mechanism, and a method as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered as a part of the claimed disclosure.
[006] In one non-limiting embodiment of the disclosure, a mechanism for a screw jack is disclosed. The mechanism comprises a nut rotatably disposed within a housing. The nut is to be mounted on a screw member of the screw jack. A gear member is defined with a plurality of teeth, the gear member being fixedly mounted around the nut. A fork is connectable to the plurality of teeth such that the fork is defined with a first tooth and a second tooth extending from either ends of the fork. The mechanism further comprises a first plunger engageable with a first portion of the fork, wherein the first plunger is configured to actuate the fork to abut the first tooth with the gear member for rotating the gear member in a first direction. A second plunger is engageable with a second portion of the fork, wherein the second plunger is configured to actuate the fork to abut the second tooth with the gear member for rotating the gear member in a second direction opposite to the first direction. The first plunger and the second plunger are selectively operable by an actuator that is to move in at least one of the first direction and the second direction.
[007] In an embodiment of the disclosure, the screw member is disposed along an axis of the screw jack and wherein the first plunger and the second plunger are configured to extend along a horizontal plane perpendicular to the axis.
[008] In an embodiment of the disclosure, the actuator is insertable in the housing along the horizontal plane to selectively engage with at least one of the first plunger and the second plunger to actuate the fork.
[009] In an embodiment of the disclosure, each of the first plunger and the second plunger are biased by at least one resilient member to displace the first plunger and the second plunger away from the fork.

[010] In an embodiment of the disclosure, the fork is actuatable upon reciprocation of the actuator between the first direction and the second direction to rotate the gear member in at least one of the first direction and the second direction to raise and lower the screw member respectively.
[011] In an embodiment of the disclosure, the mechanism comprises at least one support member positioned between the fork and the first plunger and the second plunger and is disposed within the housing.
[012] In an embodiment of the disclosure, the at least one support member is defined with a plurality of openings, and at least one of the first plunger and the second plunger are configured to pass through the plurality of openings to engage with the fork.
[013] In an embodiment of the disclosure, the fork is defined with a protrusion extending oppositely to the first tooth and the second tooth from a third portion of the fork, the third portion being disposed between the first portion and the second portion of the fork.
[014] In an embodiment of the disclosure, the mechanism comprises a support pin which is disposed between the first plunger and the second plunger. The support pin is configured to engage the protrusion to prevent abutment of the second tooth with the gear member on actuation of the first plunger to enable rotation the gear member in the first direction.
[015] In an embodiment of the disclosure, the actuator includes at least one lever defined with a tapered surface to selectively engage with the first plunger and the second plunger.
[016] In an embodiment of the disclosure, at least one retainer member is positioned in the housing, wherein the at least one retainer member is to engage with the actuator to restrict rotation of the actuator.
[017] In an embodiment of the disclosure, the at least one retainer member comprises at least one protruding member configured to engage with a plurality of holes defined on an outer periphery of the actuator to restrict rotation of the actuator.
[018] In another non-limiting embodiment of the disclosure, a screw jack is disclosed. The screw jack comprises a screw member movably disposed within a hollow column. The screw member extending and being actuatable along an axis of the screw jack. A mechanism for

actuating the screw member. The mechanism comprises a nut rotatably disposed within a housing. The nut is to be mounted on a screw member of the screw jack. A gear member is defined with a plurality of teeth, the gear member being fixedly mounted around the nut. A fork is connectable to the plurality of teeth such that the fork is defined with a first tooth and a second tooth extending from either ends of the fork. The mechanism further comprises a first plunger engageable with a first portion of the fork, wherein the first plunger is configured to actuate the fork to abut the first tooth with the gear member for rotating the gear member in a first direction. A second plunger engageable with a second portion of the fork, wherein the second plunger is configured to actuate the fork to abut the second tooth with the gear member for rotating the gear member in a second direction opposite to the first direction. The first plunger and the second plunger are selectively operable by an actuator that is to move in at least one of the first direction and the second direction.
[019] In another non-limiting embodiment of the disclosure, a method of operating a screw jack is disclosed. The method comprises inserting an actuator through a provision provided in a housing. Rotating the actuator about a horizontal plane to a first position, to engage a first plunger configured to actuate a fork. The horizontal plane is defined perpendicular to an axis defined in a longitudinal direction of the screw jack. Actuating the actuator about the axis of the screw jack to rotate a gear member in a first direction to actuate a screw member in an upward direction, the gear member is mounted on an outer periphery of a nut which is rotatably coupled to the screw member. Rotating the actuator to a second position to engage with a second plunger configured to actuate the fork to engage with the gear member. Actuating the actuator to rotate the gear member in a second direction to actuate the screw member of the screw jack in a downward direction.
[020] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.
[021] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[022] The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
Fig. 1 illustrates a perspective view of a mechanism for lifting and lowering a screw member of a screw jack in accordance with an embodiment of the present disclosure.
Fig. 2 illustrates a perspective view of the screw jack with the mechanism of Fig. 1.
Fig. 3 illustrates an exploded view of the screw jack of Fig. 2.
Figs. 4a-4d illustrates a top view of the mechanism depicting actuation of a gear member in a first direction, a second direction and corresponding neutral positions respectively in accordance with an embodiment of the present disclosure.
Fig. 5 illustrates a perspective view of a nut in accordance with an embodiment of the present disclosure.
Fig. 6 illustrates a perspective view of a gear member of the mechanism of Fig. 1, in accordance with an embodiment of the present disclosure.
Fig. 7 illustrates a perspective view of a fork in accordance with an embodiment of the present disclosure.
Fig. 8 illustrates a perspective view of an actuator in accordance with an embodiment of the present disclosure; and
Fig. 9 illustrates a front perspective view of a retainer member in accordance with an embodiment of the present disclosure.
[023] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative

embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[024] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the figure and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
[025] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of the device, mechanism and the method without departing from the scope of the disclosure. Therefore, such modifications are considered to be part of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein. Also, the mechanism of the present disclosure may be employed in various jack assemblies to lift various vehicles having different categories or specifications.
[026] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that of a mechanism that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such mechanism, a device, or a method. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the mechanism and device.
[027] Conventionally, a nut is mounted on a lead screw about internal threads of the nut. The nut is rotated in any one of a clockwise or in an anti-clockwise direction by an operator. For the rotation, a handle is engaged with the nut by positioning the handle within one hole of a plurality of holes defined circumferentially on the nut. The handle is then rotated by the operator to rotate the nut in the required direction. After rotation of the nut by an angle, the handle is removed from one hole and is positioned in another hole to rotate the nut. This operation of the handle is to be repeated multiple times for one full rotation of the nut. Further,

multiple such operations of the handle are required to achieve lifting or lowering of the jack assembly. This rotation of the nut causes the lead screw to be raised or lowered about the internal threads of the nut. This process is continued in many cycles, until the lead screw is lifted to a required height. This continuous operation of placing the handle into each hole of the plurality of holes requires a lot of effort & time which may cause fatigue to the operator due to prolonged operation. Also, as the jack assembly is positioned below the vehicle, the operator has to reaching out below the vehicle to operate the handle until the jack is lifted to a required height. This is uncomfortable and may compromise safety of the operator.
[028] In view of this, embodiments of the present disclosure disclose a mechanism for a screw. The mechanism comprises a nut rotatably disposed within a housing. The nut is to be mounted on a screw member of the screw jack. A gear member is defined with a plurality of teeth, the gear member being fixedly mounted around the nut. A fork is connectable to the plurality of teeth such that, the fork is defined with a first tooth and a second tooth extending from either ends of the fork. The mechanism further comprises a first plunger engageable with a first portion of the fork, wherein the first plunger is configured to actuate the fork to abut the first tooth with the gear member for rotating the gear member in a first direction. A second plunger engageable with a second portion of the fork, wherein the second plunger is configured to actuate the fork to abut the second tooth with the gear member for rotating the gear member in a second direction opposite to the first direction. The first plunger and the second plunger are selectively operable by an actuator that is to move in at least one of the first direction and the second direction. This configuration of the fork to selectively actuate the gear member by the plunger upon movement or reciprocation of the actuator enables lifting or lowering of the screw jack. The fork is configured to rotate the gear member continuously in the first or the second direction upon reciprocation of the actuator until the required jack height is achieved. Thus, the actuator need not be removed from the housing of the screw jack until the required height is reached. Advantageously, this enables easy operation of the screw jack with less fatigue to the operator. Also, the actuator can be operated away from a vehicle body, by increasing a length of the actuator to enable safe and comfortable operation of the screw jack. Further, lifting and lowering of the screw jack is easily performed by the proposed mechanism on continuous reciprocation of the actuator without altering its position.

[029] The following paragraphs describe the present disclosure with reference to Figs. 1 to 9. In the figures, the same element or elements which have similar functions are indicated by the same reference signs.
[030] Fig. 1 illustrates a perspective view of a screw jack (200) for lifting and lowering a vehicle. The screw jack (200) comprises [interchangeably referred to as “the jack (200)”] comprises a base (19) and a hollow column (1) extending from the base (19). The hollow column (1) is fixed to the base (19) at one end with a plurality of brackets (24) (shown in Fig. 3) capable of receiving at one fastener to secure the base (19) with the hollow column (1). The base (19) is engageable (e.g., mountable) to a ground surface or a flat surface in order to achieve traction and lift angle. A body (2) is defined with a top end and a bottom end. The body (2) is configured to extend away from the top end of the hollow column (1) defining a shoulder at the intersection of the body (2) and the hollow column (1). The body (2) is defined with a plurality of internal grooves (not shown in figs.) to receive a rotating member such as a nut (3) (shown in Fig. 3). A screw member (35) (shown in Fig.3) is movably disposed within the hollow column (1) along an axis (A-A) defined along a longitudinal direction of the jack (200). The screw member (35) is defined with a plurality of external threads (37). A load head (20) may be mounted on the screw member (35) and is configured to carry the load while lifting or lowering of the screw member (35). In an embodiment, the load head (20) may be configured as an anvil in a rectangular, square or in a circular shape.
[031] Further, with reference to Fig. 2, the present disclosure comprises a mechanism (100) which is provided to actuate the screw member (35) along the axis (A-A), which is the longitudinal direction of the jack (200). The mechanism (100) is mounted on the body (2). The mechanism (100) extends in a horizontal plane (D), which is perpendicular to the axis (A-A). The mechanism (100) comprises a housing (5) defined with a first end (16) and a second end (17) as shown in Fig. 2. The nut (3) is disposed within the housing (5) near the first end (16) such that a portion of the nut (3) is secured within the body (2) and is rotatably mounted within the body (2).
[032] In an embodiment, the nut (3) is defined with a top portion (54) and a bottom portion (56) (as shown in figs. 3 and 5). A plurality of protrusions (40) are defined circumferentially on the bottom portion (56) which engages with the plurality of internal grooves (not shown in figs.) of the body (2) to secure the bottom portion of the nut (3) within the body (2). A plurality of internal threads (38) are defined on an internal surface of the nut (3) to receive the screw

member (35). The screw member (35) is engaged within the internal threads (38) of the nut (3). Further, the nut (3) is rotatably mounted on the body (2). The nut (3) is supported by a thrust bearing (33) and the thrust bearing (33) is disposed within the housing (5). In an embodiment, the bearing (33) may also be a ball bearing or a roller bearing comprising a washer (34). Further, a first slot (39) is defined at the top portion (54) of the nut (3) to receive a key member (18).
[033] The mechanism comprises a gear member (4) that is fixedly mounted on the nut (3). A plurality of teeth (21) is defined on an outer surface of the gear member (4) and a second slot (42) is defined on an inner surface of the gear member (4). The gear member (4) is configured to rotate the nut (3) in a first direction (B) and a second direction (C) about the axis (A-A). The key member (18) is configured to fit into the first slot (39) and the second slot (42) to fixedly secure the gear member (4) around the nut (3).
[034] Now referring to fig. 3 in conjunction with fig. 4a, the exploded view of the screw jack (200) with the mechanism (100) is disclosed. The mechanism (100) further comprises a fork (6) having a front surface (44) and a rear surface (45) (shown in Fig. 4a). The fork (6) is positioned adjacent to the gear member (4) at a distance such that, the front surface (44) faces the gear member (4) along a horizontal plane (D). A cavity (43) is defined perpendicular to the horizontal plane (D) at a central portion of the fork (6) to receive a pivot pin (10). The fork (6) is pivotally secured by the pivot pin (10) at the central portion of the fork (6). The pivot pin (10) is defined with a head portion (46) engageable with a top surface of the housing (5) to hold the fork (6) in place. The fork (6) is configured to rotate about the pivot pin (10). The fork (6) is defined with a first tooth (25) and a second tooth (26) extending from either ends of the fork (6). The first tooth (25) and the second tooth (26) are defined on the front surface (44). The first tooth (25) and the second tooth (26) are configured to engage with the plurality of teeth (21) of the gear member (4) upon rotation of the fork (6) in the first direction (B) and the second direction (C) respectively. In an embodiment, the fork (6) may also be referred to as a latch, since the first tooth (25) and the second tooth (26) of the fork are involved in latching with the plurality of teeth (21) of the gear member (4).
[035] A protrusion (23) is defined on the rear surface (45) of the fork (6) and is configured to extend from the central portion of the fork (6). The protrusion (23) is configured to extend oppositely to the first tooth (25) and the second tooth (26) from a third portion (29) of the fork (6). The third portion (29) is disposed between the first portion (27) and the second portion

(28) of the fork (6). In an embodiment, the protrusion (23) is tapered with a gradual decrease in thickness from the rear surface (45) to define a first contact surface (47) and a second contact surface (48) at either sides of the protrusion (23).
[036] A first plunger (7) and a second plunger (8) are positioned within the housing (5) and are configured to extend along the horizontal plane (D). Each of the first plunger (7) and the second plunger (8) is defined with a first contact portion (49) at one end to engage with the fork (6) and a second contact portion (50) opposite to the first contact portion (49) (shown in fig. 4a). A flange (51) is defined near the second contact portion (50) of the first plunger (7) and the second plunger (8). At least one support member (30) is disposed within the housing (5) in a transverse direction with respect to the first and second plungers (7, 8). The at least one support member (30) is secured by screws (32) between the fork (6) and the first and second plungers (7, 8). In an embodiment, the at least one support member (30) is structured in a rectangular, square or any other suitable polygonal shape. At least one resilient member (22) is coupled to the flange (51) at one end and to the support member (30) at another end. Each of the first plunger (7) and the second plunger (8) are biased by at least one resilient member (22) to displace the first plunger (7) and the second plunger (8) away from the fork (6). In an embodiment, the resilient member (22) may be a spring mounted on the first plunger (7) and the second plunger (8) such that one end of the spring is connected to the flange (51) and the other end is biased about the support member (30). Further, the at least one support member (30) is defined with a plurality of openings (31) to receive least one of the first plunger (7) and the second plunger (8). The first plunger (7) and the second plunger (8) are configured to pass through the plurality of openings (31) to engage with the fork (6). When the first plunger (7) or the second plunger (8) pushes the fork (6) to engage with the gear member (4), the corresponding resilient member (22) is in a compressed state and stores energy. When the first plunger (7) and the second plunger (8) stops pushing the fork (6), the resilient member (22) returns to its relaxed position.
[037] The first plunger (7) is configured to engage with a first portion (27) of the fork (6). The second plunger (8) is configured to engage with a second portion (28) of the fork (6). The first portion (27) and the second portion (28) are defined on the rear surface (45) and are adjacent to the first contact surface (47) and the second contact surface (48) of the protrusion (23). When viewed in a width direction of the fork (6), the first portion (27) is disposed between the first tooth (25) and the protrusion (23). The second portion (28) is disposed between the

protrusion (23) and the second tooth (26). Accordingly, the first portion (27) is closer to the first tooth (25) as compared to the second tooth (26) and the second portion (28) is closer to the second tooth (26) as compared to the first tooth (25). By virtue of this arrangement, when the first plunger (7) is pushed against the first portion (27), the first tooth (25) is pushed towards the gear member (4). Accordingly, the first plunger (7) is configured to actuate the fork (6) to abut the first tooth (25) with the gear member (4). Consequently, when the first tooth (25) abuts with the gear member (4), the gear member (4) may rotate in the first direction (B), as will be explained in the subsequent paragraphs. When the second plunger (8) is pushed against the second portion (28), the second tooth (26) is pushed towards the gear member (4). Thus, the second plunger (8) is configured to actuate the fork (6) to abut the second tooth (26) with the gear member (4). When the second tooth (26) abuts with the gear member (4), the gear member (4) may rotate in the second direction (C) opposite to the first direction (B).
[038] The actuation of the first and second plungers (7, 8) (e.g., pushing the first plunger (7) against the first portion (27) and pushing the second plunger (8) against the second portion (28)) may be performed by an actuator (12). The first plunger (7) and the second plunger (8) are selectively operable by the actuator (12) when moved in at least one of the first direction (B) and the second direction (C).
[039] Furthermore, at least one support pin (15) is disposed between the first plunger (7) and the second plunger (8) (as shown in figs. 4a-4c). The at least one support pin (15) is spring loaded on its bottom portion. The at least one support pin (15) induces a constant pressure on the protrusion (23) to firmly support the fork (6), to allow actuation of any one of the first tooth (25) or the second tooth (26) to abut with the gear member (4). The support pin (15) is configured to engage the first contact surface (47) of the protrusion (23) upon rotation of the fork (6) in the second direction (C), i.e., when the second tooth (26) of the fork (6) abuts with the gear member (4). Such an engagement of the support pin (15) with the first contact surface (47) prevents the fork (6) from reversing its direction. For example, the engagement prevents the second tooth (26) from disengaging from the gear member (4) and prevents the first tooth (25) from engaging with the gear member (4). This way, the gear member (4) can only be rotated in the second direction (C). Accordingly, inadvertent reversals in the engagement of the first and second tooth (25, 26) of the fork (6) with the gear member (4) is prevented. Similarly, the support pin (15) engages the second contact surface (48) of the protrusion (23) upon rotation of the fork (6) in the first direction (B), i.e., when the first tooth (25) of the fork (6) abuts with

the gear member (4). This engagement of the support pin (15) with the second contact surface (48) prevents the fork (6) from reversing its direction. As an example, this engagement prevents the first tooth (25) from disengaging from the gear member (4) and prevents the second tooth (26) from engaging with the gear member (4) to rotate the gear member (4), only in the first direction (B).
[040] Now referring to figure 3 in conjunction with fig. 8, the housing (5) includes a provision (41) at the second end (17) to receive the actuator (12). In an embodiment, the actuator (12) may include at least one of a lever, a shaft or any suitable tool. The actuator (12) is defined with a body portion (43) and a shank (36) connected to the body portion (43) at one end. The body portion (43) and the shank (36) may be cylindrical in shape. Further, the shank (36) may have a diameter less than that of the body portion (43). Another end of the shank (36) portion is tapered to form an inclined surface. The tapered surface (13) of the actuator (12) is configured to engage (e.g., push) and displace the at least one of the first plunger (7) and the second plunger (8) towards the fork (6).
[041] The actuator (12) is defined with a plurality of holes (14) defined on an outer periphery of the shank (36). The plurality of holes (14) are circumferentially spaced apart from each other. In example, the plurality of holes (14) are apart from each other at right angles i.e. each hole (14) of the plurality of holes (14) is at an angle of 90° from another hole (14). The actuator (12) is rotated about its own axis to selectively displace at least one of the first plunger (7) and the second plunger (8) towards the fork (6). The actuator (12) is rotated in a first position to engage with the first plunger (7) and in a second position to engage with the second plunger (8). The first position corresponds to the rotation of the actuator (12) in a direction such that the taper surface (13) of the actuator (12) pushes the first plunger (7), to displace the first plunger (7) towards the fork (6). The second position of the actuator (12) corresponds to the rotation of the actuator (12) in a direction such that the taper surface (13) of the actuator (12) pushes the second plunger (8), to displace the second plunger (8) towards the fork (6). Further, at least one retainer member (9) (as shown in fig. 4a) is disposed within the housing (5) near the second end (17). The at least one retainer member (9) extends in the horizontal plane and are connected to a side walls (5a, 5b) of the housing (5) at the second end (17). The at least one retainer member (9) is externally threaded and is fixed within the housing (5) (as shown in Fig. 9). The at least one retainer member (9) is defined with a groove (52) to receive at least one protruding member (11). The at least one protruding member (11) is biased with at least one

resilient member (22) such that the at least one protruding member (11) engages the plurality of holes (14) from either sides of the shank (36). The at least one protruding member (11) is configured to restrict rotational movement of the actuator (12) about its axis. In an embodiment, the at least one protruding member (11) is a metal ball or a bearing ball which is biased toward from the actuator (12).
[042] Present disclosure also discloses a method of operating a screw jack (200). The method comprises the steps of initially inserting the at least one actuator (12) through the provision (41) provided in a housing (5). The actuator (12) is then rotated to the first position to engage the first plunger (7) to actuate the fork (6) such that the first tooth (25) engages with a tooth of the gear member (4). The first plunger (7) is selectively operated with the help of a tapered surface (13) of the actuator (12) which engages with the first portion (27) of the fork (6). Further, the actuator (12) is reciprocated continuously in the horizontal plane (D), such that the actuator (12) is moved alternately in the first direction (B) and the second direction (C) to actuate the screw member (35) in an upward direction. In an embodiment, the actuator (12) may be moved between a first extreme position and a second extreme position defined in the horizontal plane (D). The actuator (12) reaches the first extreme position upon movement of the actuator (12) in the second direction (C). Similarly, the actuator (12) reaches the second extreme position from the first extreme position upon movement of the actuator (12) in the first direction (B).
[043] Upon movement of the actuator (12) in the first direction (B), the first tooth (25) engages with a tooth of the gear member (4), say the tooth (21-1). Subsequently, when the actuator (12) is moved in the second direction (C), the first tooth (25) disengages from the tooth (21-1). This induces torque on the gear member (4) and causes the gear member (4) to rotate in the first direction (B). During rotation of the gear member (4) in the first direction (B), the first tooth (25) slips against the outer surface of the gear member (4) (as shown in fig. 4b). This rotation of the gear member (4) rotates the nut (3) also in the first direction (B). This rotation of the nut (3) in turn causes the screw member (35) to rotate along with the nut (3) to raise the screw member (35) in an upward direction.
[044] Upon completion of movement of the actuator (12) in the second direction (C), the actuator (12) may be reversed in direction, i.e., moved in the first direction (B). The reversal in the direction causes the first tooth (25) to engage with another tooth of the gear member (4), such as the tooth 21-2, 21-3, or 21-4. This engagement of the first tooth (25) with the tooth of

the gear member (4) stops rotation of the gear member (4). Subsequently, the actuator (12) may again be moved in the second direction (C) to again rotate the gear member (4) in the first direction (B). In this manner, the reciprocation of the actuator (12) may be continued between the first and second extreme positions to raise the screw member (35).
[045] When the screw member (35) is to be lowered, the actuator (12) is rotated to the second position to cause the second plunger (8) to engage the second tooth (26) with a tooth of gear member (4), say the tooth (21-5) (as shown in Fig. 4c). The second plunger (8) is selectively operated with the help of a tapered surface (13) of the actuator (12) which engages with the second portion (28) of the fork (6). Subsequently, when the actuator (12) is moved in the first direction (B), the second tooth (26) disengages from the tooth (21-5). This induces torque on the gear member (4) which causes the gear member (4) to rotate in the second direction (C). During rotation of the gear member (4) in the second direction (C), the second tooth (26) slips against the outer surface of the gear member (4) (as shown in fig. 4d). This rotation of the gear member (4) actuates the nut (3) in the second direction (C) and this actuation of the nut (3) in turn causes the screw member (35) to rotate along with the nut (3),causing lowering of the screw member (35). Upon completion of movement of the actuator (12) in the first direction (B), the actuator (12) may be reversed in direction, i.e., moved in the second direction. This reversal in the direction causes the second tooth (26) to engage with a tooth of the gear member (4), such as the tooth 21-6, 21-7, or 21-8. This engagement of the second tooth (26) with the tooth of the gear member (4) stops rotation of the gear member (4). Subsequently, the actuator (12) may be moved in the first direction (B) to enable rotation of the gear member (4) in the second direction (C). In this manner, the reciprocation of the actuator (12) may be continued between the first and second extreme positions to lower the screw member (35).
[046] The working operation of the mechanism (100) to raise and lower the screw member (35) of the screw jack (200) is now explained with reference to figs. 4a, 4b, 4c and 4d. The mechanism (100) is mounted on the body (2) of the screw jack (200) such that the portion of the nut (3) is enclosed within the body (2). The nut (3) is mounted on the screw member (35) disposed in the axis (A-A) along the longitudinal direction of the screw jack (200). Each operation of the mechanism (100) is described below:
[047] For raising the screw member (35): The screw jack (200) may be positioned below the vehicle. After positioning of the screw jack (200), initially the actuator (12) is inserted in the housing (5) through the provision (41) (as shown in fig. 4a). The actuator (12) is inserted in a

standard position or a home position which is considered at a zero-degree angle in which the actuator (12) is freely rotatable, and the retainer member (9) is not engaged with any of the plurality of holes (14) of the actuator (12). The actuator (12) is then rotated about its own axis to the first position in one direction. This rotation is carried out until the tapered surface (13) of the actuator (12) displaces the first plunger (7) towards the fork (6) to engage with the first portion (27) of the fork (6). Further, the retainer member (9) engages with the corresponding holes (14) of the plurality of holes (14) of the actuator (12) such that, further rotation of the actuator (12) is arrested. In an embodiment, the actuator (12) may be rotated in its own axis by 90° from the standard position to arrest the rotation of the actuator (12) by the retainer member (9). At this position, the first plunger (7) actuates the fork (6) to pivot about the central position of the fork (6) to engage the first tooth (25) of the fork (6) with one tooth (e.g., 21-1) of the plurality of teeth (21) of the gear member (4) (as shown in Fig. 4A). The pivotal movement of the fork (6) causes the support pin (15) to engage the second contact surface (48) of the protrusion (23). This contact of the support pin (15) and the second contact surface (48) prevents the second tooth (26) from engaging with the gear member (4). Now, the actuator (12) is reciprocated between the first extreme position and the second extreme position to alternate the movement of the actuator (12) in the first direction (B) and the second direction (C) about the horizontal plane (D).
[048] When the actuator (12) is moved in the first direction (B), the first tooth (25) engages with a tooth (21-1) of the gear member (25). Subsequently, when the actuator (12) is moved in the second direction (C), the first tooth (25) disengages from the tooth (21-1). This induces torque on the gear member (4) and causes the gear member (4) to rotate in the first direction (B) to advance the gear member (4), say, by one tooth. In an embodiment, the first tooth (25) may advance the gear member (4) by more than the one tooth of the plurality of teeth (21) depending on the amplitude of the movement of the actuator (12) in the second direction (C). During rotation of the gear member (4) in the first direction (B), the first tooth (25) slips against the outer surface of the gear member (4) (as shown in fig. 4b). This rotation of the gear member (4) actuates the nut (3) in the first direction (B). This rotation of the nut (3) in turn causes the screw member (35) to rotate along with the nut (3) to raise the screw member (35). After rotation of the gear member (4) in the first direction (B) and completion of the movement of the actuator (12) in the second direction (C), the actuator (12) is moved in the first direction (B) to start a next cycle of reciprocation of the actuator (12). When the actuator (12) is moved in the first direction (B), the first tooth (25) again engages with a next tooth (21-2) of the

plurality of teeth (21) of the gear member (4). This engagement of the first tooth (25) with tooth (21-2) of the gear member (4) stops rotation of the gear member (4) to hold the gear member (4) in place. In an embodiment, the first tooth (25) may engage with the teeth (21-3) or (21-4) based on the amplitude of the movement of the actuator (12) in the second direction (C). Subsequently, the actuator (12) may again be moved in the second direction (C) to rotate the gear member (4) in the first direction (B). In this manner, the reciprocation of the actuator (12) may be continued between the first and second extreme positions to raise the screw member (35). This raising of the screw member (35) enables the head portion (20) to lift the vehicle to a required height upon reciprocation of the actuator (12).
[049] For lowering the screw member (35): When the screw jack (200) is to be lowered, the actuator (12) is rotated about its axis to the second position in an other direction opposite to the one direction. This rotation is done till the tapered surface (13) of the actuator (12) displaces the second plunger (8) towards the fork (6) to engage with the second portion (28) of the fork (6). Further, the retainer member (9) engages with the corresponding holes (14) of the plurality of holes (14) of the actuator (12) such that, further rotation of the actuator (12) is arrested. In an embodiment, the actuator (12) may be rotated in its own axis by 180° from the standard position to arrest the rotation of the actuator (12) by the retainer member (9). Consequently, the second plunger (8) actuates the fork (6) to pivot about the central position of the fork (6) to engage the second tooth (26) of the fork (6) with a tooth of the gear member (4) (as shown in Fig. ). At this position, the support pin (15) engages the first contact surface of the protrusion (23) to allow the actuation of the second tooth (26) and prevents the first tooth (25) from engaging with the gear member (4). Now, the reciprocation of the actuator (12) is carried out between the first and second extreme positions.
[050] Initially, when the actuator (12) is moved in the second direction (C), the second tooth (26) engages with a tooth (21-5) of the gear member (25) (as shown in Fig. 4c). Subsequently, when the actuator (12) is moved in the first direction (B), the second tooth (26) disengages from the tooth (21-5). This induces torque on the gear member (4) and causes the gear member (4) to rotate in the second direction (C) to advance the gear member (4), say, by one tooth (21-6). In an embodiment, the second tooth (26) may advance the gear member (4) by more than one tooth of the plurality of teeth (21) depending on the amplitude of the movement of the actuator (12) in the first direction (B). During rotation of the gear member (4) in the second direction (C), the second tooth (26) slips against the outer surface of the gear member (4) (as

shown in fig. 4d). This rotation of the gear member (4) actuates the nut (3) in the second direction (C). This rotation of the nut (3) in turn causes the screw member (35) to rotate along with the nut (3) of the nut (3) to lower the screw member (35). After rotation of the gear member (4) in the second direction (C) and completion of the movement of the actuator (12) in the first direction (B), the actuator (12) is moved in the second direction (C) to start a next cycle of reciprocation of the actuator (12). Further, when the actuator (12) is moved in the second direction (C), the second tooth (26) again engages with a next tooth (21-6) of the plurality of teeth (21) of the gear member (4). This engagement of the second tooth (26) with the tooth of the gear member (4) stops rotation of the gear member (4). In an embodiment, the second tooth (26) may engage with the teeth (21-7) or (21-8) based on the amplitude of the movement of the actuator (12) in the first direction (B). Subsequently, the actuator (12) may again be moved in the first direction (B) to rotate the gear member (4) in the second direction (C). In this manner, the reciprocation of the actuator (12) may be continued between the first and second extreme positions to lower the screw member (35). This lowering of the screw member (35) enables the head portion (20) to lower the vehicle to the required height.
[051] In an embodiment, the body portion of the screw jack (200), the nut (3) and the screw member (35) may be manufactured by a metallic material such as stainless steel or forged steel having high load bearing capabilities to withstand heavy loads.
[052] In an embodiment, the mechanism (100) may be installed on a nut body (2) of various screw jacks (200) for easy lifting and lowering of the screw member (35).
[053] In an embodiment, the actuator (12) may be continuously reciprocated without separating from the nut (3) of the mechanism (100) due to continuous actuation of the gear member (4) with the fork (6). This enables easy and quick operation of the screw jack (200) for lifting the loads.
[054] The actuator (12) may be operated from outside the vehicle by simply reciprocating the actuator (12) from the outside, without going to the underside of the vehicle. This ensures safety of the operator without the risk of accidents such as sudden falling of the vehicle in an event of failure of the screw jack (200) during its operation.
[055] In an embodiment, the actuator (12) may be operated manually or by any automatic mechanism by use of any motor for reciprocation of the actuator (12).

[056] This eliminates the need for changing the actuator (12) from one nut (3) hole to another which is the case in conventional screw jacks (200). Advantageously. this reduces fatigue to the operator.
[057] The screw jack (200) of the present disclosure requires less effort and enables any person to operate by simple rotation and reciprocation of the actuator (12).
[058] The screw jack (200) of the present disclosure can be operated by a single operator without requiring help from another person for changing the position of the actuator (12) within different nut holes.
[059] It is to be understood that a person of ordinary skill in the art may develop a mechanism or a device of similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.
Equivalents:
[060] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[061] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the

introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Referral Numerals:

Mechanism 100
Screw jack 200
Hollow column 1

Body 2
Nut 3
Gear member 4
Housing 5
Fork 6
First plunger 7
Second plunger 8
Retainer member 9
Pivot pin 10
Protruding member 11
Actuator 12
Tapered surface 13
Plurality of holes 14
Support pin 15
First end 16
Second end 17
Key member 18
Base 19
Load head 20
Plurality of teeth 21
Resilient member 22
Protrusion 23
A plurality of brackets 24
First tooth 25
Second tooth 26
First portion 27
Second portion 28

Third portion 29
Support member 30
A plurality of openings 31
Screws 32
Bearing 33
Oil seal 34
Screw member 35
Shank 36
A plurality of external threads 37
A plurality of internal threads 38
first slot 39
Plurality of protrusions 40
Provision 41
Second slot 42
Cavity 43
Front surface 44
Rear surface 45
Head portion 46
First contact surface 47
Second contact surface 48
First contact portion 49
Second contact portion 50
Flange 51
Groove 52
Top portion 54
Bottom portion 56

WE CLAIM:
1. A mechanism (100) for a screw jack (200), the mechanism (100) comprising:
a nut (3) rotatably disposed within a housing (5), and the nut (3) to be mounted on a screw member (35) of the screw jack (200);
a gear member (4) defined with a plurality of teeth (21), the gear member (4) being fixedly mounted around the nut (3);
a fork (6) connectable to the plurality of teeth (21), wherein the fork (6) is defined with a first tooth (25) and a second tooth (26) extending from either ends of the fork (6),
a first plunger (7) engageable with a first portion (27) of the fork (6), wherein the first plunger (7) is configured to actuate the fork (6) to abut the first tooth (25) with the gear member (4) for rotating the gear member (4) in a first direction (B);
a second plunger (8) engageable with a second portion (28) of the fork (6), wherein the second plunger (8) is configured to actuate the fork (6) to abut the second tooth (26) with the gear member (4) for rotating the gear member (4) in a second direction (C) opposite to the first direction (B); and
wherein the first plunger (7) and the second plunger (8) are selectively operable by an actuator (12) that is to move in at least one of the first direction (B) and the second direction (C).
2. The mechanism (100) as claimed in claim 1, wherein the screw member (35) is disposed along an axis (A-A) of the screw jack (200) and wherein the first plunger (7) and the second plunger (8) are configured to extend along a horizontal plane (D) perpendicular to the axis (A-A).
3. The mechanism (100) as claimed in claim 2, wherein the actuator (12) is insertable in the housing (5) along the horizontal plane (D) to selectively engage with at least one of the first plunger (7) and the second plunger (8) to actuate the fork (6).
4. The mechanism (100) as claimed in claim 1, wherein each of the first plunger (7) and the second plunger (8) are biased by at least one resilient member (22) to position the first plunger (7) and the second plunger (8) away from the fork (6).

5. The mechanism (100) as claimed in claim 1, wherein the fork (6) is actuatable upon reciprocation of the actuator (12) between the first direction (B) and the second direction (C) to rotate the gear member (4) in at least one of the first direction (B) and the second direction (C) to raise and lower the screw member (35) respectively.
6. The mechanism (100) as claimed in claim 1 comprises at least one support member (30) positioned between the fork (6) and the first plunger (7) and the second plunger (8) and disposed within the housing (5).
7. The mechanism (100) as claimed in claim 6, wherein the at least one support member (30) is defined with a plurality of openings (31), and at least one of the first plunger (7) and the second plunger (8) are configured to pass through the plurality of openings (31) to engage with the fork (6).
8. The mechanism (100) as claimed in claim 1, wherein the fork (6) is defined with a protrusion (23) extending oppositely to the first tooth and the second tooth from a third portion (29) of the fork (6), the third portion (29) being disposed between the first portion (27) and the second portion (28) of the fork (6).
9. The mechanism (100) as claimed in claim 8, comprising a support pin (15) disposed between the first plunger (7) and the second plunger (8), wherein the support pin (15) is configured to engage the protrusion (23) to prevent abutment of the second tooth (26) with the gear member (4) on actuation of the first plunger (7) to enable rotation the gear member (4) in the first direction (B).
10. The mechanism (100) as claimed in claim 1, comprising the actuator (12), wherein the actuator (12) includes at least one lever defined with a tapered surface (13) to selectively engage with the first plunger (7) and the second plunger (8).
11. The mechanism (100) as claimed in claim 3, comprising at least one retainer member (9) positioned in the housing (5), wherein the at least one retainer member (9) is to engage with the actuator (12) to restrict rotation of the actuator (12).
12. The mechanism (100) as claimed in claim 11, wherein the at least one retainer member (9) comprises at least one protruding member (11) configured to engage with a plurality

of holes (14) defined on an outer periphery of the actuator (12) to restrict rotation of the actuator (12).
13. A screw jack (200) comprising:
a screw member (35) movably disposed within a hollow column (1); the screw member (35) extending and being actuatable along an axis (A-A);
a mechanism (100) for actuating the screw member (35), the mechanism (100) comprising:
a nut (3) rotatably disposed within a housing (5), the nut (3) being mounted on the screw member (35) of the screw jack (200);
a gear member (4) defined with a plurality of teeth, the gear member (4) being fixedly mounted around the nut (3);
a fork (6) connectable to the plurality of teeth (21),wherein the fork (6) is defined with a first tooth (25) and a second tooth (26) extending from either ends of the fork (6),
a first plunger (7) engageable with a first portion (27) of the fork (6), wherein the first plunger (7) is configured to actuate the fork (6) to abut the first tooth (25) with the gear member (4) for rotating the gear member (4) in a first direction (B);
a second plunger (8) engageable with a second portion (28) of the fork (6) and the second plunger (8) is configured to actuate the fork (6) to abut the second tooth (26) with the gear member (4) for rotating the gear member (4) in a second direction (C) opposite to the first direction (B);
wherein the first plunger (7) and the second plunger (8) are selectively operable by an actuator (12) that is to move in in at least one of the first direction (B) and the second direction (C) to raise and lower the screw member (35) respectively.
14. The screw jack (200) as claimed in claim 14, wherein the screw member (35) is
disposed along an axis (A-A) of the screw jack (200) and wherein the first plunger (7)
and the second plunger (8) are configured to extend in a horizontal plane (D)
perpendicular to the axis (A-A).

15. The screw jack (200) as claimed in claim 14, wherein the actuator (12) is insertable in the housing along the horizontal plane (D) to selectively engage with at least one of the first plunger (7) and the second plunger (8) to actuate the fork (6).
16. The screw jack (200) as claimed in claim 14, wherein each of the first plunger (7) and the second plunger (8) are biased by at least one resilient member (22) to displace the first plunger (7) and the second plunger (8) away from the fork (6).
17. The screw jack (200) as claimed in claim 14, wherein the fork (6) is actuatable upon reciprocation of the actuator (12) between the first direction (B) and the second direction (C) to rotate the gear member (4) in at least one of the first direction (B) and the second direction (C).
18. A method of operating a screw jack (200), the method comprising;
inserting an actuator (12) through a provision provided in a housing (5);
rotating the actuator (12) about a horizontal plane (D) to a first position, to engage a first plunger (7) configured to actuate a fork (6); the horizontal plane (D) is defined perpendicular to an axis (A-A) defined in a longitudinal direction of the screw jack (200);
actuating the actuator (12) about the axis (A-A) to rotate a gear member (4) in a first direction (B) to actuate a screw member (35) in an upward direction, the gear member (4) is mounted on an outer periphery of a nut which is rotatably coupled to the screw member (35);
rotating the actuator (12) to a second position to engage with a second plunger (8) configured to actuate the fork (6) to engage with the gear member (4); and
actuating the an actuator (12) to rotate the gear member (4) in a second direction (C) to actuate the screw member (35) of the screw jack (200) in a downward direction.