DESCRIPTION
Technical Field of the Invention
The present invention relates to the field of bionic arms. More specifically the present invention is directed to a wrist device used in bionic arms that can be controlled by the users.
Background of the Invention
The wrist device allows the human beings to accomplish sophisticated movements. It allows the human beings to complete the tasks accurately. The loss of arm or arms can significantly affect the level of sovereignty and the capability of performing daily living, means working and social activities of an individual. Different types of bionic hands have been developed to provide the solution for the same. Most of the bionic hands are used for robotic purpose which has no inbuilt functions in it.
Bionic arm usually has three main parts namely palm base with five fingers, wrist and forearm socket attached to the residual limb of the user. Fingers attached to palm part are actuated through linear actuator mechanism to enable multiple grasping behaviors and postures. For the bionic arm to perform various grip patterns and to hold objects of different sizes and shapes requires wrist to move in different positions.
At present there are several types of bionic hands with different functionalities such as the Body-Powered Prosthesis, the Electrical Hand. But these hands can't be adjustable to multiple positions and can't grasp objects of various sizes and shapes. There is no wrist position locking system with minimal components in the known devices.
Therefore, there are many prosthetic wrist units for bionic arms. The prior art U.S Patent No: 7048768, entitled: Multi-Function Body Powered Prosthetic Wrist Unit and Method discloses a wrist unit that is attachable at the end of the prosthetics on an arm and provides over 270° of smooth

pronation and supination rotation with a plurality of indexed rotation locking positions, wrist flexion and extension from 0 to 50° with three locking positions.
The other Prior art U.S Patent No. 8795387, entitled: Prosthetic Wrist discloses A prosthetic wrist for attaching between an arm prosthesis and a prosthetic accessory includes proximal section, a central section pivotally attached to the proximal section with a first joint, and a distal section pivotally attached to the central section with a second joint. The second joint includes a second pivot axis that is substantially orthogonal to and non-intersecting with the first pivot axis. There are locking pins allowing the pivot arm to rotate about the pivot pin and allows the user to fix at an angle along a first and second axis. However, in this device there is no disclosure of rotatable wrist with multiple locking positions. Moreover, the invention employs heavy components and an expensive manufacturing process for the locking the positions.
The other prior art is U.S. 7914587, entitled: Wrist Device for Use with a Prosthetic Limb includes a base plane that is configured for attachment to a prosthetic limb. A cross piece, having first and second axes, can be coupled to the base plate. A prosthetic attachment can be coupled to the cross piece. The cross piece can enable a user to simultaneously flex the prosthetic attachment in two different axes. This mechanism allows the user to lock in one or more positions with several components incorporated in it. However, the major criteria is to reduce the size of the device by using limited components and achieve multiple locking positions.
However, by considering the current available prosthetic wrist devices the length and weight of prosthetic wrist will have major impact in case of wrist disarticulation amputees, where overall length of the bionic arm depends on length of the wrist that connects palm and forearm socket. For example, if a person having amputation for one hand cannot imagine a bionic hand longer than his normal hand. Existing wrists devices are too large and includes many components as a result they are heavy, long and does not appeal to many amputees such as children and women. Therefore, the weight of the prosthetic wrist adds up to overall weight of palm and the wrist combination and user feels it difficult to rotate in multiple positions. These things limit usefulness of the prosthesis.

Therefore, to overcome the aforementioned limitations there is need to develop an improved wrist device that can rotate the prosthetic wrist in multiple locking positions. Another need is that the improved prosthetic wrist device should be light in weight, compact in size, easy to manufacture, easy to operate, smooth in operation and user friendly.
Brief Summary of the Invention
It is therefore an object of the present invention to develop an improved wrist device for bionic arm.
It is an object of the present invention to build a wrist device that can move and lock in seven different positions.
It is an object of the present invention to provide a wrist device that is operated completely based on the user input and can lock at an accurate position to withstand heavy loads.
Another object of the present invention is to develop a wrist device that is easy to operate, manufacture. The assembly design of wrist device can be extended to multiple locking positions by increasing number of teeth on the cogwheel.
Yet another object of the present invention is to develop a wrist device that enables the user to grasp objects of various shapes and sizes.
Another object of the present invention is to develop a wrist multi position locking device with minimal number of components.
According to an aspect of the present invention, the invention includes a wearable device for bionic arm. The device comprises a wrist palm end with a rectangular slot, a wrist forearm distal end engages with the forearm socket, a wrist palm base, a compression spring, an indexing wedge, a cogwheel, a circlip, a power control board (PCB) and a microcontroller.

In accordance with the aspect of the present invention, the wrist palm end is rotatably mounted on the wrist forearm end and the said forearm end is fixed to the forearm socket.
In accordance with the aspect of the present invention, the wrist palm end has a projection with a grove to insert circlip to bind the said wrist palm end and the wrist fore-arm end for eliminating any sort of lateral movement among them.
In accordance with the aspect of the present invention, the indexing wedge of the wrist palm end is initially configured to be in the locking position Wl considered as reference position.
In accordance with the aspect of the present invention, the indexing wedge of the wrist palm end is configured with seven possible movements referred to as W1,W2,W3,W4, W5 , W6 & W7 at an interval of 30 degrees with its engagement with the cogwheel upon the users rotation of the wrist.
In accordance with the aspect of the present invention, the cogwheel has stoppers for indexing wedge movement at end of Wl and W7.
In accordance with the aspect of the present invention, on applying rotational force on wrist palm end for 30 degrees in anti-clockwise direction with respect to reference position Wl, locking position W2 is obtained by compression of the spring and movement of indexing wedge in upward direction.
In accordance with the aspect of the present invention, the indexing wedge movement results in the cogwheel dis-engagement from the said indexing wedge and enables the wrist palm end to move freely in desired angles.
In accordance with the aspect of the present invention, the wrist palm end can be rotated in both clockwise and anti-cock wise direction.

In accordance with the aspect of the present invention, the user is provided to adjust the wrist in multiple locking positions and thereby enables the user to grasp objects of various shapes and sizes.
In accordance with the aspect of the present invention, the wrist palm base is rotatably fixed to the wrist palm end, the palm base is equipped with linear actuators for the opening and closing of fingers.
From a reading of the description above of the preferred frameworks of the present invention, modifications and variations thereto may occur to those skilled in the art. Therefore, the scope of the present invention is to be limited only by the claims of this invention.
Brief Description of the Drawings
The present invention is illustrated by accompanying drawings, wherein:
Fig. 1 illustrates the Exploded view depicting the components involved in designing the Improved Wrist Device according to the present invention.
Fig.2 illustrates the top view depicting the Wrist locking positions according to the present invention.
Fig. 3 illustrates the Sectional view depicting the arrangement of components included in designing the bionic arm device according to the present invention.
Fig.4 illustrates the exploded view depicting the Power Distribution (PCB) assembly to wrist according to the present invention.
Fig.5 illustrates the front view depicting the Wrist integration with palm according to the present invention.

Fig.6 illustrates the side view depicting the Wrist assembly to Palm using screws according to the present invention.
Fig.7 illustrates the Assembled view depicting the arrangement of fingers, palm and wrist according to the present invention.
Detailed Description of the Invention
The following description is merely exemplary in nature and is not intended to limit the present invention, applications, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
The present invention provides a wrist device for bionic arm that can move and lock in seven different positions that can be controlled by the users.
The present invention relates to an improved wrist device used in bionic arms that can be controlled by the users. The said bionic arm usually has three main parts namely palm base with five fingers, wrist and forearm socket attached to the residual limb of the user. Fingers attached to palm part are actuated through linear actuator mechanism to enable multiple grasping behaviors and postures. For the bionic arm to perform various grip patterns and to hold objects of different sizes and shapes requires wrist to be locked in different positions.
The proposed improved wrist device comprises: a wrist palm end with a rectangular slot at one end engages with palm base co-axially, a wrist forearm distal end engages with the forearm socket to support the bionic arm, a wrist palm base interconnected with five fingers and positioned with a linear actuator for the movement of said fingers, a compression spring housed in slot provided in wrist palm end to engage and disengage the indexing wedge, an indexing wedge slidably mounted inside the slot of the wrist palm end and locks the cog wheel in a specific position, a cogwheel housed in wrist palm end constitute seven locking positions to lock the wrist in specific position desired by the user, a circlip binds the wrist palm end and wrist forearm end from preventing lateral movements, a power control board PCB mounted on wrist forearm end for

distributing power to various electronic components of the bionic hand and a microcontroller housed inside the wrist palm controls the linear actuators for opening and closing of fingers.
The wrist palm end is rotatably mounted on the wrist forearm end and the said forearm end is fixed to the forearm socket. The wrist palm end can be rotated in both clockwise and anti-cock wise direction. The wrist palm base is rotatably fixed to the wrist palm end, the palm base is equipped with linear actuators for the opening and closing of fingers. This wrist palm end has a projection with a grove to insert circlip to bind the said wrist palm end and the wrist fore-arm end for eliminating any sort of lateral movement among them.
The wrist device includes an indexing wedge, cog wheel and a compression spring that helps in locking the wrist in multiple locking positions. The compression spring housed in slot provided in wrist palm end engages and disengages the indexing wedge. The indexing wedge is slidably mounted inside the slot of the wrist palm end and locks the cogwheel in a specific position. The cogwheel housed in wrist palm end constitute seven locking positions to lock the wrist in specific position desired by the user. The cogwheel teeth and said indexing wedge radially gets engaged thus preventing the lateral movement of wrist palm end relative to wrist forearm end. The indexing wedge of the wrist palm end is configured with seven possible movements referred to as Wl, W2, W3, W4, W5, W6 & W7 at an interval of 30 degrees with its engagement with the cogwheel upon the user's movement of the arm. The cogwheel has stoppers for indexing wedge movement at end ofWl andW7.
According to the present invention, on applying rotational force on wrist palm end for 30 degrees in anti-clockwise direction with respect to reference position Wl, locking position W2 is obtained by compression of the spring and movement of indexing wedge in upward direction. The indexing wedge movement results in the cogwheel dis-engagement from the said indexing wedge and enables the wrist palm end to move freely in desired angles.
The wrist palm base interconnected with five fingers regarding performing activities of the individual and positioned with a linear actuator for the movement of said fingers. The user is provided to adjust the wrist in multiple locking positions and thereby enables the user to grasp

objects of various shapes and sizes with minimal number of components. The improved wrist device is completely user input based that gives accurate locking position and can take heavy loads.
Referring to the drawings, Fig. 1 illustrates the Exploded view (100) depicting the components involved in designing the Improved Wrist Device according to the present invention. The improved wrist device for bionic arm comprises a circlip (1), screws (2), a wrist forearm end (3), a cogwheel (4), an indexing wedge (5), a compression spring (6) and wrist palm end (7).
The circlip (1) used binds the wrist palm end (7) and the wrist fore-arm end (3). The wrist palm end (7) has a projection with a grove to insert the circlip (1). To the wrist palm end (7) a cog wheel (4), an indexing wedge (5) and a compression spring (6) are arranged which help in rotating and locking the wrist in multiple positions. Screws (2) are used for fixing cogwheel (4) to wrist fore¬arm end (3). The compression spring (6) is housed in slot provided in the wrist palm end (7) to engage and disengage the indexing wedge (5). A cogwheel (4) is housed in the wrist palm end (7) constitute seven locking positions that lock the wrist in specific position desired by the user and an indexing wedge slidably mounted inside the slot of the wrist palm end (7) locks the cog wheel (4) in a specific position.
The wrist palm end (7) can be rotated in both clockwise and anti-cock wise direction. User can apply rotational force on wrist palm end (7) and anti-clockwise rotation of the wrist palm end (7) for 30 degrees with respect to reference position will result in compression of the compression spring (6) and the indexing wedge (5) moves in upward direction. The wrist palm end (7), is rotatably mounted on the wrist forearm end (3) and the said forearm end (3) is fixed to the forearm socket.
The indexing wedge (5) will be initially at locking position Wl (Reference position), with cogwheel (4) teeth. The moment of indexing wedge (5) results in the dis-engagement of cogwheel (4) from the said indexing wedge (5) and enables the wrist palm end (7) to move freely in desired angles. The indexing wedge (5) engaged with cog wheel (4) prevents movement of wrist palm end (7) relative to wrist forearm end (3). Once the user stops applying force on the wrist palm end (7), the compression spring (6) force pushes the indexing wedge (5) and the indexing wedge (5) gets

engaged with cogwheel (4) teeth, this locks the wrist in locking position W2.
Fig.2 illustrates the top view (200) depicting the Wrist locking positions according to the present invention. The wrist locking system includes a cogwheel (4), an indexing wedge (5) and a compression spring (6). The compression spring (6) is housed in slot provided in wrist palm end (7) to engage and disengage the indexing wedge (5). The indexing wedge (5) is slidably mounted inside the slot of the wrist palm end (7) to lock the cogwheel (4) in a specific position. The cogwheel (4) housed in wrist palm end (7) constitute seven locking positions to lock the wrist in specific position desired by the user. The cogwheel (4) teeth and the indexing wedge (5) radially gets engaged and thus prevents the lateral movement of wrist palm end (7) relative to wrist forearm end (3).
The indexing wedge (5) of the wrist palm end (7) is configured with seven possible movements referred to as Wl, W2, W3, W4, W5, W6 & W7 at an interval of 30 degrees with its engagement with the cogwheel (4) upon the user's movement of the arm. The cogwheel (4) has stoppers for indexing wedge (5) movement at end of Wl and W7. By applying rotational force on wrist palm end (7) for 30 degrees in anti-clockwise direction with respect to reference position Wl, locking position W2 is obtained by compression of the compression spring (6) and movement of indexing wedge (5) in upward direction.
Fig.3 illustrates the Sectional view (300) depicting the wrist according to the present invention. Fig. 3, shows a circlip (1), a wrist forearm end (3), a cogwheel (4), an indexing wedge (5), a compression spring (6), and a wrist palm end (7). The said wrist palm end (7) has a projection with a grove to insert circlip (1) to bind the said wrist palm end (7) and the wrist fore-arm end (3) for eliminating any sort of lateral movement among them. The cogwheel (4) teeth and indexing wedge (5) radially gets engaged thus preventing the lateral movement of wrist palm end (7) relative to wrist forearm end (3).The indexing wedge (5) movement results in the cogwheel (4) dis¬engagement from the said indexing wedge (5) and enables the wrist palm end (7) to move freely in desired angles. A compression spring (6) housed in the slot provided in wrist palm end (7) engages and disengages the indexing wedge (5). The user is provided to adjust the wrist in multiple locking positions and thereby enables the user to grasp objects of various shapes and sizes.

Fig.4 illustrates the exploded view (400) depicting the Power Distribution (PCB) assembly to wrist according to the present invention. The improved wrist device comprises a Power Control PCB (9) for distributing power to various electronic components of the bionic hand. The power distribution PCB (9) is mounted to wrist fore-arm end (3) using screws (8).
Fig.5 illustrates the front view (500) depicting the Wrist integration with palm according to the present invention. The wrist forearm end (3) and the wrist palm end (7) are interconnected to palm base (13). The wrist palm base (13) is rotatably fixed to the wrist palm end (7), the palm base (13) is equipped with linear actuators (12) for the opening and closing of fingers. The palm base is embedded with a microcontroller printed circuit boards (10) & (11) and connected to the wrist palm end (7) to control the actuators (12) that are housed inside the palm.
The locking position system is assembled between the wrist forearm end (3) and wrist palm end (7). The locking system has seven locking positions that are arranged at an interval of 30 degrees and are adjustable and controlled by the user. The assembly wrist design can be extended to multiple locking positions by inserting more teeth on the cog wheel.
Fig.6 illustrates the side view (600) depicting the Wrist assembly to Palm using screws according to the present invention. The wrist forearm end (3) is locked to palm base (13) using screws (14). The wrist palm base (13) interconnected with five fingers and positioned with a linear actuator (12) for the movement of fingers.
Fig.7 illustrates the Assembled view (700) depicting the arrangement of fingers, palm and wrist according to the present invention. The wrist device has three main parts namely palm base with five fingers, wrist and forearm socket attached to the residual limb of the user. The wrist palm end (7) engages with the palm base (13) and the forearm end (3) engages with forearm socket. A plurality of slots are provided on the wrist forearm end (3), so that the forearm end (3) is fixed to the forearm socket using screws. The wrist palm end (7) is rotatable and Wrist forearm end (3) is fixed to forearm socket.

A locking system with cog wheel, compression spring and indexing wedge is integrated in the wrist palm end (7). A cogwheel is housed in the wrist palm end (7) has three holes, so that it can be fixed to Wrist forearm end (3) using screws (2).
The improved wrist device allows the human beings to accomplish sophisticated movements. It enables the human beings to complete the tasks accurately. By using improved wrist device user can move and lock his arm in seven different positions. This device provides the user to adjust and lock the wrist in multiple positions. The wrist device is designed with minimum number of components and enables the user to grasp objects of various shapes and sizes.
The wrist device is completely user input based and gives accurate position locking and can take heavy loads.
In one embodiment, the proposed prosthetic wrist device can be manufactured either in plastic or in metal. The observed weight of the prosthetic wrist device using plastic material is 60 grams and it is 100 grams when manufactured using aluminum. Approximate length of the proposed prosthetic wrist is 34mm and can be manufactured in 43mm and 53mm diameters which makes it usable for both trans radial amputation and wrist disarticulation.
From the description above it is clear that various changes could be done to the preferred wrist device without departing from the scope of the invention.

5. CLAIMS I/We Claim
1. An improved wrist device (100) for bionic arm comprises:
a wrist palm end (7) with a rectangular slot at one end engages with palm base co-
axially;
a wrist forearm distal end (3) engages with the forearm socket to support the bionic
arm;
a wrist palm base (13) interconnected with five fingers and positioned with a linear
actuator (12) for the movement of said fingers;
a compression spring (6) housed in slot provided in wrist palm end (7) to engage
and disengage the indexing wedge (5);
an indexing wedge (5) slidably mounted inside the slot of the wrist palm end (7)
and locks the cog wheel (4) in a specific position;
a cogwheel (4) housed in wrist palm end (7) constitute seven locking positions to
lock the wrist in specific position desired by the user;
a circlip (1) binds the wrist palm end (7) and wrist forearm end (3) from preventing
lateral movements;
a power control board PCB (9) mounted on wrist forearm end (3) to distribute
power to various electronic components of the bionic hand;
a microcontroller (10 & 11) housed inside the wrist palm controls the actuators (12)
to open and close the said fingers; characterized by:
wherein, the wrist device (100) with all the components mentioned above are mounted co-axially to each other;
wherein, the seven locking positions are arranged at an interval of 30 degrees and are adjustable and controlled by the user;
wherein, the improved wrist device (100) is designed to rotate the prosthetic wrist in multiple locking positions as desired by the user;
wherein, the improved wrist device (100) is designed with minimum number of components and enables the user to grab objects of various shapes and sizes;

wherein, the improved wrist device (100) can be usable for both the users complaining with
trans radial amputation and wrist disarticulation;
wherein, the improved wrist device (100) is manufactured with approximate length of
34mm and diameter of 43mm and 53mm which impacts the overall weight of the palm and
user feels convenient while rotating the wrist in multiple positions; and
wherein, by considering the overall length, diameter and the components utilized the
improved wrist device (100) is light in weight, compact in size, easy to manufacture, easy
to operate, smooth in operation and user friendly.
2. The improved wrist device (100) as claimed in claim 1, wherein the wrist palm end (7) is rotatably mounted on the wrist forearm end (3) and the said forearm end (3) is fixed to the forearm socket.
3. The improved wrist device (100) as claimed in claim 1, wherein the wrist palm end (7) has a projection with a grove to insert circlip (1) to bind the said wrist palm end(7) and the wrist fore-arm end (3) for eliminating any sort of lateral movement among them.
4. The improved wrist device (100) as claimed in claim 1, wherein the indexing wedge (5) of the wrist palm end (7) is initially configured to be in the locking position Wl considered as reference position. The cogwheel (4) teeth and said indexing wedge (5) radially gets engaged thus preventing the lateral movement of wrist palm end (7) relative to wrist forearm end (3).
5. The improved wrist device (100) as claimed in claim 1, wherein the indexing wedge (5) of the wrist palm end (7) is configured with seven possible movements referred to as W1,W2,W3,W4, W5 , W6 & W7 at an interval of 30 degrees with its engagement with the cogwheel (4) upon the users movement of the arm.
6. The improved wrist device (100) as claimed in claim 1, wherein the cogwheel (4) has stoppers for indexing wedge (5) movement at end of Wl and W7.

7. The improved wrist device (100) as claimed in claim 1, wherein the assembly design of the wrist device (100) can be extended to multiple locking positions by increasing number of teeth on the cog wheel (4).
8. The improved wrist device (100) as claimed in claim 1, wherein on applying rotational force on wrist palm end (7) for 30 degrees in anti-clockwise direction with respect to reference position Wl, locking position W2 is obtained by compression of the compression spring (6) and movement of indexing wedge (5) in upward direction.
9. The improved wrist device (100) as claimed in claim 1, wherein the indexing wedge (5) movement results in the cogwheel (4) dis-engagement from the said indexing wedge (5) and enables the wrist palm end (7) to move freely in desired angles.
10. The improved wrist device (100) as claimed in claim 1, wherein the wrist palm end (7) can be rotated in both clockwise and anti-cock wise direction.
11. The improved wrist device (100) as claimed in claim 1, wherein the user is provided to
adjust the wrist in multiple locking positions and thereby enables the user to grasp objects
of various shapes and sizes.
12. The improved wrist device (100) as claimed in claim 1, wherein the wrist palm base (13) is rotatably fixed to the wrist palm end (7), the palm base (13) is equipped with linear actuators (12) for the opening and closing of the fingers.
13. The improved wrist device (100) as claimed in claim 1, wherein a plurality of slots are provided on the wrist forearm end (3), so that the forearm end (3) is fixed to the forearm socket using screws.