DESC:FIELD OF THE INVENTION
The present invention relates to a prosthetic device. More specifically, the present invention is directed to develop a user-removable gripping system which can be mounted on a prehensor style prosthetic device in a perpendicular position relative to jaw and can also be mounted in various positions relative to the prehensor jaw, on the axis perpendicular to the jaw. The present system can enables the present prehensor based prosthetic device to include an extra degree of freedom on each jaw of the device to provide maximal contact with the object to be grabbed with manual changeable gripper orientation and ability to retain its position, as applicable or desired.

BACKGROUND OF THE INVENTION
More than 1.6 million people around the world are considered to be upper-body amputees, having lost all or a portion of an upper limb. Of these amputees, a segment of will use a prosthetic arm to partially restore dextrous capabilities and look forward to a better quality of life. While a number of prosthetic devices have been developed to assist these individuals, their use is not wide-spread due, at least in part, to the poor performance and design of existing prosthetics and prehensors.

Prehensor style prosthetic devices are created for users in case of loss of their original upper limbs. Such devices grasp objects by squeezing an object between two or more jaws that are mechanically loaded with spring force and actuated by the user through muscle power transmitted by the use of a harness and cable. The grasping interface is typically made with rubber or silicone to improve contact friction and have a rigid structure underneath for ample force to grip the object.

Around 80% of the causes of amputation is due to trauma. There is a disproportionate loss of livelihood to people who were employed in physically intensive jobs. The limb impairment reduces employability of skilled workers and pushes economically-sensitive segments of the amputees closer to poverty. Such jobs require usage and manipulation of various tools and machinery in highly-demanding environments. Current prehensors are rudimentary in nature in comparison to the wide range of demands in each field.

In ["The GRASP Taxonomy of Human Grasp Types," in IEEE Transactions on Human-Machine Systems, vol. 46, no. 1, pp. 66-77], T. Feix, J. Romero, H. -B. Schmiedmayer, A. M. Dollar and D. Kragic mentions 31 different types of grasp patterns for a biological human hand involved in activities of daily living.

In ["Evaluating Reachable Workspace and User Control Over Prehensor Aperture for a Body-Powered Prosthesis,"] in IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 28, no. 9, pp. 2005-2014, A. Chadwell, L. Kenney, D. Howard, R. T. Ssekitoleko, B. T. Nakandi and J. Head mention that the reachable workspace while wearing a body-powered split hook prosthesis is reduced by between 15 and 62% across a range of tasks.

US7867287B2 describes a hand prosthesis that includes a chassis to which a number of finger prostheses are articulated. Each of the finger prostheses are movable relative to the chassis and toward one another about at least one swiveling axis via a drive that is connected to the finger prostheses by a force transmission unit.

US3802302A describes a tool holding a prosthetic device including a connector for attachment to an artificial body member and a tool or set of tools wherein the connector and tools are provided with snap-fit connecting means.

US20090287316A1 shows a voluntary opening prosthetic split hook terminal device is provided with an adjustable pinch force, functional grasping contours and illumination capabilities.

US7341295B1 details a prehensor is provided comprising embodiments of a variable mechanical advantage mechanism, the prehensor including a first mechanical advantage for sizing an object, and a second mechanical advantage for gripping the object.

US2666928A is adapted for attachment of a tool in a chuck-like assembly on an upper limb amputee.

WO2009140644A1 describes a prosthetic hand with digits with dual internal edges and logarithmic spiral contours for enhanced grasping of objects.

US4,225,983 is a prehensor prosthetic device with an internal hook and 3 cooperating gripping surfaces on a two-jaw construction.

Based on the prior arts, the following drawbacks need to be addressed
1. Current hook and prehensor prosthesis are still unable to provide substantial independence for one-handed operations
2. Prehensor devices have one fixed configuration of its grippers, making it infeasible to hold objects across multiple grasp patterns
3. Current interchangeable prosthetic devices are highly specific and non configurable, forcing amputees to carry around multiple attachments for a series of tasks in workplaces.
4. The shoulder muscles of amputees are greatly strained while operating body powered prehensor devices to compensate for reduced reach while grasping objects in scenarios where it would not be the case if they were able-bodied.

OBJECTIVE OF THE INVENTION:
The objective of the present invention is to develop a gripping system for a prehensor-based prosthetic hand that can be configured about its degree of freedom of rotation.

Another objective of the present invention is to develop a changeable position gripper design which can improves the ergonomics of using a prosthetic hand by allowing the user to manipulate the gripper to let them attain the most comfortable posture possible.

Another objective of the present invention is to develop a gripping system which can allow the user to use their prosthetic hand in both power gripping and precision gripping scenarios with the same hardware by modifying the position of the grippers.

Another objective of the present invention is to simulate multiple grasp patterns by a user-configurable gripping system.

Another objective of the present invention is to allow the prehensor to adapt itself for a range of tasks by allowing the user to remove the gripping apparatus and fitting a relevant alternative apparatus as required.

Another objective of the present invention is compensate for reduction in the reachable area of the prosthesis by the virtue of its gripping system design

SUMMARY OF THE INVENTION:

Thus, according to the basic aspect of the present invention there is provided a gripping system for mounting on a prehensor style prosthetic device comprising

a chassis (102);

two jaws (100, 101) pivotally mounted onto said chassis (102) around an axis (108) under a spring bias, said jaws (100, 101) are openable and closable by virtue of the spring bias around the axis (108);

grippers (103,104) on distal end of each of the jaws (100, 101) in a selective position relative to the jaws (100, 101) on axis perpendicular to the jaws (100, 101) enabling the prehensor based prosthetic device to include an extra degree of freedom on each of the jaws (100, 101) which provides maximal contact with object to be grabbed involving manual changeable gripper orientation and ability to retain its position, as applicable or desired.

In a preferred embodiment of the present system, the jaws (100, 101) are made of a rigid technopolymer and includes conical volumes (105, 106) at the distal end thereof to secure the grippers (103, 104) in the user-desired position.

In a preferred embodiment of the present system, the conical volumes (105, 106) include circular-gear profiled mechanical interface (107) allows for corresponding mating profiles (109, 110) of the grippers (103, 104) to stay secured with the jaws (100, 101).

In a preferred embodiment of the present system, the spring bias includes a torsion spring 202 of metal mounted in between the jaw bodies to provide force to lodge the grippers (103,104) into a locked position.

In a preferred embodiment of the present system, the spring (202) is made from metal wire and terminates in two arms (203, 204) at a right angle on the jaw bodies.

In a preferred embodiment of the present system, gripper bodies (200 and 201) each of the gripper include a protruding geometry (205 and 206) respectively.

In a preferred embodiment of the present system, the gripper consists of a curved surface (302) made of a rubber material for enhanced grasp capabilities having two volumes (303 and 304) which have protruding geometry 306 and 307 respectively for placing inside negative volume (305) of the jaw;

wherein torsion spring (308) is mounted between volumes the (303 and 304) and secured into the protrusions (306 and 307) through holes (309 and 310).

In a preferred embodiment of the present system, the gripper (400) includes a spring (403) housed between volumes (401 and 402) of the gripper (400) against curved geometries (404 and 405) present in the volumes (401 and 402) respectively;

wherein the volumes (401 and 402) consist of holes (406 and 407), through which arms (410 and 411) of the torsion spring (403) are secured with the gripper volumes (401 and 402);

wherein volume (408) overlaps with the jaw at (409), preventing the gripper (400) from dislodging out of the jaw, while the spring (403) exerts force along direction (412) on volumes (401 and 402) to retain the gripper (400) in place with the jaw.

In a preferred embodiment of the present system, the gripper (500) changes its position of when its two volumes (501 and 502) are pinched together using the fingers at position (503 and 504) respectively to rotate the bodies inwards about the pivot axis of spring (505), whereby arms (506 and 507) of the spring (505) pull protrusions (508 and 509) of the volumes (501 and 502) respectively towards each other which enables an overlap between surfaces (511 and 512) to be ceased and allows for the gripper protrusions (508 and 509) to slide out of the jaw’s negative volume (510), thereby allowing the gripper to be removed.

In a preferred embodiment of the present system, the gripper (702) is rotatable about an axis (705) in user-desired position where protrusions (706 and 707) mate with respective circular gear profiles (708 and 709) of the jaw.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
FIG. 1 is a perspective view of the disclosed embodiments where the grippers are in its default position.

FIG. 2 is an exploded view of the disclosed embodiments.

FIG. 3 is a cross section view of the gripper along the longitudinal plane of the prehensor.

FIG. 4 is a partial cross section view of the gripper in its engaged position along the longitudinal plane of the prehensor.

FIG. 5 is a partial cross section view of the gripper in its disengaged position along the longitudinal plane of the prehensor.

FIG. 6 is a partial cross section view showcasing the gripper removed from the jaw.

FIG. 7 is a perspective view showcasing the gripper rotated about the axis of its attachment interface.

FIG. 8 is a perspective view showcasing the gripper secured in the prehensor jaw, in an alternative position.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWING:
The present invention provides a first-of-its-kind gripper that can be removed and replaced with a different gripper hardware more suited for a different task. In the present invention, the gripping system allows the user to grasp the object with more comfortable posture as the grippers can be individually configured in the most convenient position that is conducive for grasping the object. In the present invention, the gripping system allows the user to mount the gripper in a specific position of rotation on the axis that is perpendicular to the prehensor jaw. The user is greatly benefitted as they can adapt the same hardware for both power grip and precision grip scenarios.

The present invention consists of a gripping system hardware with a lining of a soft, high-friction material on its contact surface. The top of the gripping system has an extrusion in the shape of a gear with a set number of teeth. The prehensor has a cavity at its distal end, which consists of a negative of the gear profile present in the gripping system. The top of the gripper with the gear profile is inserted into the cavity of the prehensor jaw, thereby mating with the negative of the profile present. A strong friction fit allows the gripper to stay in contact with the jaw while mated. The gear profile consists of rotationally symmetric teeth which are in contact. This allows the gripping system to be inserted into the jaw cavity in multiple positions of rotation with respect to the jaw.

FIG. 1 establishes the setup and configuration of the gripper system in a prehensor prosthetic device. Two jaws 100 and 101, made of a rigid technopolymer, are mounted onto chassis 102. These jaws pivot around the axis 108 to open and close by virtue of a spring force embedded in the chassis assembly 102. At the distal end of the jaws a conical volume 105 and 106 secures the grippers 103 and 104 in the user-desired position. A circular-gear profiled mechanical interface 107 allows for the corresponding mating profiles 109 and 110 of the gripper 104 to stay secured with the jaw 101.
FIG. 2 showcases an exploded view of the gripper system consisting of two volumes of rigid plastic - 200 and 201. A torsion spring 202 of metal is mounted in between bodies 200 and 201 to provide the force to lodge the gripper bodies 103,104 into locked position. The spring 202, made from metal wire terminates in two arms 203 and 204 at a right angle. Gripper bodies 200 and 201 include a protruding geometry 205 and 206 respectively.

FIG. 3 illustrates a cut-section view of the gripper system along the longitudinal axis of the invention. This illustration describes grippers 300 and 301 to be identical with the same construction and components. Gripper 300 consists of a curved surface 302 made of a rubber material for enhanced grasp capabilities. Gripper 300 consists of two volumes 303 and 304 which have protruding geometry 306 and 307 respectively. These protrusions 306 and 307 are placed inside negative volume 305 of the jaw. Torsion spring 308 is mounted between volumes 303 and 304 and secured into the protrusions 306 and 307 through holes 309 and 310.

In FIG. 4, the assembly of the gripper system is shown in detail, spring 403 is housed between volumes 401 and 402 of the gripper 400 against the curved geometries 404 and 405 present in the volumes 401 and 402 respectively. Volumes 401 and 402 consist of holes 406 and 407, through which the arms 410 and 411 of the torsion spring 403 are secured with the gripper volumes 401 and 402. The volume 408 overlaps with the jaw at 409, preventing the gripper 400 from dislodging out of the jaw. Spring 403 exerts force along direction 412 on volumes 401 and 402 to retain the gripper 400 in place with the jaw.

FIG. 5 describes the change in the position of gripper 500 when its two volumes 501 and 502 are pinched together using the fingers at position 503 and 504 respectively to rotate the bodies inwards about the pivot axis of the spring 505. The arms 506 and 507 of the spring 505 pull the protrusions 508 and 509 of the volumes 501 and 502 respectively towards each other. Thereby, the overlap between surfaces 511 and 512 ceases and allows for the gripper protrusions 508 and 509 to slide out of the jaw’s negative volume 510, thereby allowing the gripper to be removed. FIG. 6 shows the gripper 600 removed from the jaw cavity 602 along the direction of 601.

FIG. 7 shows the gripper system in a scenario where the gripper 702 is rotated about the axis 705 after it is removed manually out of the jaw 700. The gripper 703 is rotated to user-desired position where the protrusions 706 and 707 mate with respective circular gear profiles 708 and 709 of the jaw 701. FIG. 8 illustrates the grippers 800 and 801 fully secured at a user-desired position with the jaws 802 and 803 for operation of the prosthesis.

,CLAIMS:WE CLAIM:

1. A gripping system for mounting on a prehensor style prosthetic device comprising

a chassis (102);

two jaws (100, 101) pivotally mounted onto said chassis (102) around an axis (108) under a spring bias, said jaws (100, 101) are openable and closable by virtue of the spring bias around the axis (108);

grippers (103,104) on distal end of each of the jaws (100, 101) in a selective position relative to the jaws (100, 101) on axis perpendicular to the jaws (100, 101) enabling the prehensor based prosthetic device to include an extra degree of freedom on each of the jaws (100, 101) which provides maximal contact with object to be grabbed involving manual changeable gripper orientation and ability to retain its position, as applicable or desired.

2. The system as claimed in claim 1, wherein the jaws (100, 101) are made of a rigid technopolymer and includes conical volumes (105, 106) at the distal end thereof to secure the grippers (103, 104) in the user-desired position.

3. The system as claimed in claim 1 or 2, wherein the conical volumes (105, 106) include circular-gear profiled mechanical interface (107) allows for corresponding mating profiles (109, 110) of the grippers (103, 104) to stay secured with the jaws (100, 101).

4. The system as claimed in claims 1 to 3, wherein the spring bias includes a torsion spring 202 of metal mounted in between the jaw bodies to provide force to lodge the grippers (103,104) into a locked position.

5. The system as claimed in claims 1 to 4, wherein the spring (202) is made from metal wire and terminates in two arms (203, 204) at a right angle on the jaw bodies.

6. The system as claimed in claims 1 to 5, wherein gripper bodies (200 and 201) each of the gripper include a protruding geometry (205 and 206) respectively.

7. The system as claimed in claims 1 to 6, wherein the gripper consists of a curved surface (302) made of a rubber material for enhanced grasp capabilities having two volumes (303 and 304) which have protruding geometry 306 and 307 respectively for placing inside negative volume (305) of the jaw;

wherein torsion spring (308) is mounted between volumes the (303 and 304) and secured into the protrusions (306 and 307) through holes (309 and 310).

8. The system as claimed in claims 1 to 6, wherein the gripper (400) includes a spring (403) housed between volumes (401 and 402) of the gripper (400) against curved geometries (404 and 405) present in the volumes (401 and 402) respectively;

wherein the volumes (401 and 402) consist of holes (406 and 407), through which arms (410 and 411) of the torsion spring (403) are secured with the gripper volumes (401 and 402);

wherein volume (408) overlaps with the jaw at (409), preventing the gripper (400) from dislodging out of the jaw, while the spring (403) exerts force along direction (412) on volumes (401 and 402) to retain the gripper (400) in place with the jaw.

9. The system as claimed in claims 1 to 6, wherein the gripper (500) changes its position of when its two volumes (501 and 502) are pinched together using the fingers at position (503 and 504) respectively to rotate the bodies inwards about the pivot axis of spring (505), whereby arms (506 and 507) of the spring (505) pull protrusions (508 and 509) of the volumes (501 and 502) respectively towards each other which enables an overlap between surfaces (511 and 512) to be ceased and allows for the gripper protrusions (508 and 509) to slide out of the jaw’s negative volume (510), thereby allowing the gripper to be removed.

10. The system as claimed in claims 1 to 6, wherein the gripper (702) is rotatable about an axis (705) in user-desired position where protrusions (706 and 707) mate with respective circular gear profiles (708 and 709) of the jaw.

Dated this the 14th day of September, 2023. Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent), IN/PA-199