DESC:Technical Field of the Invention

The present invention relates to the field of bionic hands, more particularly to the design of thumb swiveling system for bionic hand that can be controlled by the user and attains various critical locking positions of the thumb.

Background of the Invention

Prosthetic arms have been available for use, for example by amputees, for many years. More recently, mechanical and robotic components have been introduced into prosthetic arms to provide a wide range of functionality to the prosthetic arm, for example, individual finger joints controlled with various control mechanisms and finger joints controlled based on users muscle control. However, conventional upper extremity prosthetic devices can be expensive and can take a long time to produce, which may make them unsuitable or undesirable for many uses.

Some advanced electric hands on the market use a linkage mechanism to move the fingers to grab objects and perform tasks. This generally means that the fingers have a predetermined motion path and are unable to confirm to objects. Some prosthetic hands include mechanical hooks for grasping. While these prosthetics include highly functional components and is rejected by individuals because of huge mechanical appearance on the body. In addition to this many prosthetic devices employ various mechanisms for achieving various arm movements.

Most of the patents disclose a micro controller PCB present inside the palm part of the bionic hand that reads the input signals coming from user through EMG sensors and will convert them into useful grip patterns based on the input signal that user has given. The grip execution depends on the thumb position. For example, if user wants to hold objects like eraser and keys, this is not possible if thumb is in first locking position or third locking position. Similarly, if user wants to hold objects like visiting card, credit card and knife, this is not possible if thumb is in first locking position or second locking position. Hence, there is a need to track the thumb position for which the present invention proposes the use of a color sensor to track the thumb finger position.

Prior art U.S Patent No: 2008/O 188952 discloses the prosthetic or artificial hand with several pre-position able joints. Pre-position able joints include a multi-axial thumb joint, a metacarpal-phalangeal joint and a wrist joint. The prosthetic hand also include a number of pre-position able phalanges or fingers having a segmented construction, which allows them to be placed in various positions. The multi-axis thumb joint includes an attachment member with a U-bolt that interconnects a thumb member to a palm plate. The thumb may move along the attachment member to achieve neutral and pronated positions. Additionally, the thumb may move around the attachment member to achieve open and closed positions. The thumb joint additionally includes a thumb spring, which applies a tensile force to a fabric cord, which is, in turn, interconnected to the thumb.

Another patent, U.S Patent No: 2017/0049583 disclose a prosthetic hand device with a hand frame having a differential mechanism connected to an actuable index finger unit, at least one actuable secondary finger unit and an actuable thumb unit. The actuable thumb unit includes a plurality of lockable positions, wherein each lockable position corresponds to a different grasping configuration of the prosthetic hand. The differential mechanism of actuating the thumb uses a bar and pin joints for attaining thumb movements.

Other patent U.S Patent No: 2020/0054464 uses a type of body-powered terminal mechanisms with a prosthetic digit, an engagement portion and a stopping portion. The prosthetic digit enables the individual fingers to lock in different positions with respect to the force applied on the device. Also, a typical prosthetic device uses actuators for the individual finger movement.

In spite of these many prior art patents GB2572945A and WO2019139866A1 discloses a bionic hand with thumb finger that is controlled by linear actuator. But, these patents lack in disclosing position adjustable feature and feed back system for thumb finger.

The other patent US 2013/0046395 A1 discloses about motor driven thumb member consisting of plurality of gear arrangements in which the position determining apparatus comprise a rotary potentiometer or an encoder. It also comprises a plurality of switches with each switch being operative when thumb member is at different position. By using plurality of gears and switches the thumb member consumes lot of space, increases cost of manufacturing and these kind of systems may not suit for building smaller bionic hands for kids and women.

This system determines the position of thumb using plurality of switches and rotary potentiometer whose life reduces after few thousands of cycles which will result in an error in position determination and ultimately leads to malfunctioning of the bionic hand. In spite of this, the position determining apparatus is in physical contact with the rotation mechanism which leads to failure of components and generates error in the system.

Hence, there is a need to build a contactless position feedback system that is accurate, compact in size and maintenance free. Along with this, there is a need to develop a user adjustable thumb swiveling system with position feedback.

All the above references focus on achieving the effective grasping motion to the prosthetic devices using various mechanisms but none of them employ user feedback system and a separate thumb swiveling system with a micro controller to achieve selected locking positions of the thumb as in the present invention.

Brief Summary of the Invention

The present invention relates to the field of bionic arms. More specifically the present invention is directed to a thumb finger swiveling system used in bionic hands.

It is therefore an object of the present invention to develop a thumb finger swiveling system with position feedback for bionic arm.

It is an object of the present invention to develop a swiveling system that is completely user input based and gives accurate position locking and can take heavy loads.

It is an object of the present invention to build a thumb finger swiveling system with position feedback and can move to three different positions.

It is an object of the present invention to develop a swiveling system that is easy to manufacture and assembly design of swivel comprise a color sensor for position tracking.

Another object of the present invention is to develop a way of detecting thumb finger position using color sensor which is accurate and cost effective.

Another object of the present invention is to provide user adjustable multiple position locking thumb finger swiveling system that enables the user to grasp objects of various shapes and sizes.

According to an aspect of the present invention, the invention includes a thumb finger swiveling system for bionic hand. The device comprises a swivel with teeth, a grub screw, a compression spring, a jaw, a thumb finger, a housing, a color pallet with three slots t1, t2 and t3, a color sensor, a flexible Silicone rubber covering, a position sense PCB and a microcontroller PCB.

In accordance with the aspect of the present invention, the position sense PCB is provided with a slot. Wherein, a dowel pin passes through it and a nylon bush is placed between position sense PCB and the swivel so, that the position sense PCB is held firmly.

In accordance with the aspect of the present invention, the position sense PCB output is connected to input pin of a microcontroller PCB which continuously reads the data coming from color sensor present on the position sense PCB.

In accordance with the aspect of the present invention, the top end of the swivel has a through hole for incorporating the thumb finger of the bionic hand with suitable fastening elements preferably pivot pin and pivot screw.

In accordance with the aspect of the present invention, the color pallet is fixed to swivel with a snap fit, the pallet having three slots t1, t2 and t3 is fixed to the swivel such that the said pallet moves along with the swivel.

In accordance with the aspect of the present invention, the said slots t1, t2 and t3 are coated with BLUE, GREEN and RED colors respectively.

In accordance with the aspect of the present invention, upon the swivel movement, the color pallet moves along with the swivel, the color sensor present on the position sense board PCB records the reflecting light from the colored slots present on the color pallet and sends the corresponding digital value of color to microcontroller PCB that detects the thumb finger position.

In accordance with the aspect of the present invention, the algorithm running in microcontroller PCB detects the digital return of color sensor corresponding to the slots t1, t2 & t3 and decides the position of thumb finger.

In accordance with the aspect of the present invention, the digital return of reflecting light coming from slots t3, t2 & t1 corresponds to locking positions L1, L2 & L3 respectively.

In accordance with the aspect of the present invention, the swivel is proposed to have three locking positions namely L1, L2 & L3 which are attained by applying rotational force on the swivel.

In accordance with the aspect of the present invention, the swivel is initially at locking position L1 (reference position) with swivel teeth and jaw that are engaged from preventing movement of swivel relative to palm base.

In accordance with the aspect of the present invention, on applying rotational force on the swivel in clockwise direction with respect to the reference locking position L1, locking position L2 and locking position L3 are obtained by compression of the spring and the movement of jaw in downward direction.

In accordance with the aspect of the present invention, the user can rotate the swivel in anti-clockwise direction to comeback to any required position.

Brief Description of the Drawings

The present invention is illustrated by accompanying drawings, wherein:

Fig.1 illustrates the Exploded view depicting the Thumb finger swiveling system according to the present invention.

Fig. 2 illustrates the Assembled view depicting the position sense PCB and color pallet with swivel according to the present invention.

Fig.3 illustrates the front view depicting the Color pallet positioned with three slots t1, t2 and t3 according to the present invention.

Fig.4 illustrates the Sectional view depicting the thumb finger swiveling system according to the present invention.

Fig.5 illustrates the Thumb jaw and swivel locking mechanism according to the present invention.

Fig.6 illustrates the exploded view depicting the Thumb finger assembly to swiveling system according to the present invention.

Fig.7 illustrates the assembled view depicting the arrangement of Thumb finger swiveling system with Palm according to the present invention.

Fig. 8a, 8b and 8c illustrates a front view depicting the three locking positions while holding/griping various objects 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 relates to the field of bionic hand and it is directed to a thumb finger swiveling system used in bionic hands that can be controlled by the users.

The present invention is a thumb finger swiveling system used in bionic arms. 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 behavior’s and postures. The ability of the bionic arm to hold various shaped objects majorly depends on the thumb swiveling system which is pivot mounted on a palm base. The thumb can pivot relative to the palm base in order to move to different positions.

The proposed thumb swiveling system comprises: a swivel with teeth that is pivoted to the palm base using a dowel pin that moves over a jaw, a grub screw is positioned inside the dowel pin to arrest axial movement of the dowel pin during swivel rotation, a compression spring housed in the palm base ensures that swivel and jaw are locked in certain position, a jaw holding the spring oscillates up and down and keeps the swivel intact to the pivot axis, a thumb finger is associated to the swiveling system through a pivot pin and pivot screw, a Dowel pin anchors the thumb finger spring to the swivel, a housing is arranged to incorporate a bearing and a pivot pin and pivot screw to fix the thumb finger to swivel, a color pallet with three slots t1, t2 and t3 is fixed to the swivel such that the said pallet moves along with the swivel.

The color pallet is fixed to swivel with a snap fit and a color sensor is positioned on position sense PCB that records the reflecting light from slots t1, t2, t3 of color pallet and gives the position feedback of the thumb. A flexible Silicone rubber covering is covered over the swiveling system near the base of thumb finger to protect the mechanical components inside the palm base. A position sense PCB is fixed between palm housing and swivel to sense the position of the thumb finger and a microcontroller PCB present inside the palm continuously reads the output of the position sense PCB.

The swiveling system designed is completely user input based and gives accurate position locking and can withstand heavy loads.

The position sense PCB is provided with a slot. Wherein, a dowel pin passes through it and a nylon bush is placed between position sense PCB and the swivel so, that the position sense PCB is held firmly. The position sense PCB output is connected to input pin of a microcontroller PCB which continuously reads the data coming from color sensor present on the position sense PCB. The top end of the swivel has a through hole for incorporating the thumb finger of the bionic hand with suitable fastening elements preferably pivot pin and pivot screw.

The color pallet is fixed to swivel with a snap fit, the pallet having three slots t1, t2 and t3 is fixed to the swivel such that the pallet moves along with the swivel. The slots t1, t2 and t3 are coated with BLUE, GREEN and RED colors respectively. Upon the swivel movement, the color pallet moves along with the swivel, the color sensor present on the position sense board PCB records the reflecting light from the colored slots present on the color pallet and sends the corresponding digital value of color to microcontroller PCB that detects the thumb finger position.

The algorithm running in microcontroller PCB detects the digital return of color sensor output corresponding to the slots t1, t2 & t3 and decides the position of thumb finger. The digital return of reflecting light coming from slots t3, t2 & t1 corresponds to locking positions L1, L2 & L3 respectively. The swivel is proposed to have three locking positions namely L1, L2 & L3 which are attained by applying rotational force on the swivel. The swivel is initially at locking position L1 (reference position) with swivel teeth and jaw that are engaged from preventing movement of swivel relative to palm base.

On applying rotational force on the swivel in clockwise direction with respect to the reference locking position L1, locking position L2 and locking position L3 are obtained by compression of the spring and the movement of jaw in downward direction. The user can rotate the swivel in anti-clockwise direction to comeback to any required position.

Referring to the drawings, Fig.1 illustrates the Exploded view depicting the Thumb finger swiveling system according to the present invention. The thumb finger swiveling system for bionic arm comprises a swivel (1), a Position sense PCB (2), a color pallet (3), a spring (4), the palm base (5), a dowel pin (6), a grub screw (7), a jaw (8) and a nylon bush (9). The thumb swiveling system is designed to provide the position feedback and can move to three different positions.

A swivel (1) with teeth that is pivoted to the palm base (5) using a dowel pin (6), that moves over a Jaw (8). A grub screw (7) inserted into the dowel pin (6) arrests the axial movement of dowel pin (6) during swivel (1) rotation. A compression spring (4) is housed in the palm base (5), so that spring (4) force ensures that swivel (1) and jaw (8) are locked in certain position while moving the thumb (10). A jaw (8) holding the spring (4) oscillates up and down and keeps the swivel (1) intact to the pivot axis.

A color pallet (3) accommodated with three slots t1, t2 and t3 is fixed to the swivel (1) using snap fit, so that it moves along with the swivel (1). The Slots t1, t2, t3 as shown in Fig. 3 are coated with BLUE, GREEN and RED colors respectively. A color sensor (not shown) is present on position sense PCB (2) that records the reflecting light coming from color pallet (3) and gives the position feedback of the thumb (10) as shown in Fig. 3. The position sense PCB (2) is provided with a slot through which a dowel pin (6) passes through it and a nylon bush (9) is placed between position sense PCB (2) and the swivel (1) so that the position sense PCB 2 is held firmly.

The position sense PCB (2) output is connected to input pin of a microcontroller PCB (not shown) that continuously reads the data coming from color sensor present on the position sense PCB (2). Whenever swivel (1) moves, the color pallet (3) also moves along with swivel (1) and the color sensor present on position sense PCB (2) records the reflecting light and sends the data to microcontroller PCB which detects the position of the thumb (10). The reflecting light from t3, t2, t1 corresponds to locking positions L1, L2, L3 respectively.

Fig. 2 illustrates the Assembled view (200) depicting the position sense PCB and color pallet with swivel according to the present invention. The swivel (1) with teeth comprises a color pallet (3), a position sense PCB (2), a spring (4), a jaw (8) and a nylon bush (9). On one side of the swivel (1) a position sense PCB (2) with color sensor is arranged and on the other side of the swivel (1) a color pallet (3) is connected. To the end of the swivel (1) a jaw is connected, the jaw (8) holds the spring (4) to oscillate up and down and keeps the swivel (1) intact to the pivot axis.

The position sense PCB (2) is provided with a slot through which a dowel pin (6) passes through it and a nylon bush (9) is placed between position sense PCB (2) and the swivel (1) so that the position sense PCB 2 is held firmly. The position sense PCB (2) output is connected to input pin of a microcontroller PCB (not shown) which continuously reads the data coming from color sensor present on the position sense PCB (2).

Whenever swivel (1) moves, the color pallet (3) also moves along with swivel (1) and the color sensor present on position sense PCB (2) records the reflecting light and sends the data to microcontroller PCB which detects the position of the thumb (10).

Fig. 3 illustrates the front view (200) depicting the Color pallet positioned with three slots t1, t2 and t3 according to the present invention. The color pallet (3) is designed with three slots t1, t2 and t3 and is fixed to the swivel (1) using a snap fit. Whenever swivel (1) moves, the color pallet (3) also moves along with swivel (1). The slots t1, t2 and t3 are coated with BLUE, GREEN and RED colors respectively.

Upon the swivel (1) movement, the color pallet (3) moves along with the swivel (1), the color sensor present on the position sense board PCB (2) records the reflecting light coming from the colored slots present on the color pallet (3) and sends the corresponding digital value of color to microcontroller PCB (2) that detects the thumb finger position. The algorithm running in microcontroller PCB detects the digital return of color sensor corresponding to the slots t1, t2 & t3 and decides the position of thumb finger.

Fig. 4 illustrates the Sectional view (300) depicting the thumb finger swiveling system according to the present invention. Fig.3 shows us the swivel (1), the spring (4), the palm base (5), a jaw (8), a thumb finger (10), the flexible silicone rubber covering (13) and a pivot pin (14). The swivel (1) with teeth that is pivoted to the palm base (5) using a dowel pin (6), moves over a Jaw (8). The compression spring (4) that is housed in the palm base (5) ensures that swivel (1) and jaw (8) are locked in certain position. The jaw (8) holding the spring (4) oscillates up and down and keeps the swivel (1) intact to the pivot axis.

A housing is arranged to incorporate a bearing (15), a pivot pin (14) and pivot screw (16) to fix the Thumb finger (10) to swivel (1). The thumb finger (10) is associated to the swiveling system through a pivot pin (14) and pivot screw (16) as shown in Fig. 5. The dowel pin (12) anchors the thumb finger spring (11) to swivel (1). A flexible Silicone rubber covering (13) is covered over the swiveling system near the base of thumb finger (10) to protect the mechanical components inside the palm base (5). The Thumb finger 10 swiveling system is provided with three locking positions namely L1, L2 and L3.

Fig. 5 illustrates the Thumb jaw and swivel locking mechanism (400) according to the present invention. The swivel (1) is proposed to have three locking positions namely L1, L2 & L3 which are attained through position sense PCB functioning explained in Fig.1. The swivel (1) is initially at locking position L1(reference position) with swivel (1) teeth and jaw (8) engaged preventing movement of swivel relative to palm base (5). The Position sense PCB (2) is fixed between palm housing (5) and swivel (1) to sense the position of the thumb finger. The color sensor present on position sense PCB (2) records the reflecting light coming from slots t1, t2 & t3. The reflecting light coming from t3, t2, t1 corresponds to locking positions L1, L2, L3 respectively. A microcontroller PCB continuously reads the data coming from color sensor present on the position sense PCB (2) and decides the position of thumb finger.

At this point (Locking position L1), the Color sensor present on Position sense PCB (2) will now record the reflecting light from Red Colored slot t3, this information is read by microcontroller PCB and Thumb finger (10) position is sensed.

User can swivel to locking position L2 by rotating the swivel (1) in clockwise direction for 9.4 degrees with respect to reference locking position L1. This rotation results in compression of the spring (4) and moment of jaw (8) in downward direction. As a result, the jaw (8) gets dis engaged from swivel (1) and enables it to move freely. Once the user stops applying force on the swivel (1), the spring (4) expands and the jaw (8) gets engaged with swivel (1) teeth, this locks the swivel (1) in locking position L2.

At this point (Locking position L2), the Color sensor present on Position sense PCB (2) will now record the reflecting light from Green Colored slot t2, this information is read by microcontroller PCB and Thumb finger (10) position is sensed.

Thumb finger (10) swiveling system further comprises of one more locking position L3. User can swivel to locking position L3 by rotating the swivel (1) in clockwise direction for 74.4 degrees with respect to reference position L1. Once the user stops applying force on the swivel (1), the spring (4) expands and the jaw (8) gets engaged with swivel (1) teeth thus locks the swivel (1) in locking position L3.

At this point (Locking position L3), the color sensor present on position sense PCB (2) will now record the reflecting light from Blue Colored slot t1, this information is read by microcontroller PCB and Thumb finger (10) position is sensed.

Fig. 6 illustrates the exploded view (500) depicting the Thumb finger assembly to swiveling system according to the present invention. The thumb finger assembly comprises a palm base (5), a thumb finger (10), a thumb finger spring (11), a dowel pin (12), a flexible silicone rubber covering (13), a pivot pin (14), a bearing (15) and a pivot screw (16). A housing is arranged to incorporate a bearing (15) and a pivot pin (14) and pivot screw (16) to fix the Thumb finger (10) to swivel (1). The top end of the swivel (1) has a through hole for incorporating the thumb finger (10) of the bionic hand with suitable fastening elements preferably pivot pin (14) and pivot screw (16). The key component of thumb finger swiveling system is swivel (1). The Jaw (8) is another key component that engages with the swivel (1) and enables the swivel (1) to rotate. The pitch and tooth depth of the swivel (1) are chosen based on the requirement of thumb position for holding various objects. Swivel (1) is pivoted to the palm base (5) using a dowel pin (6).

The thumb finger (10) is associated to the swiveling system through a dowel pin (12). The dowel pin (12) anchors the thumb finger spring (11) to the swivel (1). A flexible Silicone rubber covering (13) is covered over the swiveling system near the base of thumb finger (10) to protect the mechanical components inside the palm base (5).

Fig. 7 illustrates the assembled view (600) depicting the arrangement of Thumb finger swiveling system with Palm according to the present invention. The thumb finger (10) is associated to the swiveling system (700) which comprise a position feedback mechanism. The position of the thumb is sensed by the color sensor present on position sense PCB (2) that records the reflecting light from color pallet (3) gives the position feedback of the thumb. The thumb swiveling system (1) with position feedback can move to three different locking positions.

On applying rotational force on the swivel (1) in clockwise direction with respect to the reference locking position L1, locking position L2 and locking position L3 are obtained by compression of the spring (4) and the movement of jaw (8) in downward direction. The color sensor present on Position sense PCB (2) will record the reflecting light coming from the slots of color pallet, this information is read by microcontroller PCB and Thumb finger (10) position is sensed.

A flexible Silicone rubber covering (13) is covered over the swiveling system near the base of thumb finger (10) to protect the mechanical components inside the palm base (5). The swiveling system (1) is completely user input based that gives accurate locking position and can take heavy loads.

By using the proposed the thumb finger swiveling system, the user can rotate the swivel (1) in anti-clockwise direction to comeback to any required position.

Fig. 8a, 8b and 8c illustrates a front view (700) depicting the three locking positions of the thumb finger while holding/griping various objects according to the present invention. The thumb finger in a bionic hand plays a key role in holding various objects. Thumb finger in bionic hand needs two different kinds of motion, one is thumb should be able to swivel so that user can adjust the position according to the target object that user is trying to hold, another is closing and opening of thumb finger which actually happens using a linear actuator. Thumb finger closes and opens using a linear actuator that is present inside the palm. The linear actuator pulls and pushes the tendon passing through the thumb finger which results in closing and opening action of the thumb finger.

The grip execution mainly depends on the thumb position. For example, if user wants to hold objects like pen and/or pencil to write something the thumb finger must be in opposed position with respect to index finger and middle finger. The Fig. 7a shows the first locking position by moving the thumb finger associated with the swiveling system.

For example, if user wants to hold small objects like eraser, keys etc., the thumb finger must be in opposed position with respect to the index finger. The Fig. 7b shows the second locking position by moving the thumb finger associated with the swiveling system.

For example, if user wants to hold objects like visiting card, knife, etc. the thumb finger must be in non-opposed position with respect to other fingers. The Fig. 7c shows the third locking position by moving the thumb finger associated with the swiveling system.

In one embodiment, the grip user wants to use completely depends on the type of object that user wants to hold, and it is dynamic.

In other embodiment, the proposed invention mainly focusses on developing a position feedback system using color sensor that is cost effective, compact in size, easy to manufacture and use.

From the description above it is clear that various changes could be done to the preferred thumb swiveling system without departing from the scope of the invention.
,CLAIMS:1. A thumb finger (10) swiveling system designed for bionic hand with position feedback system wherein the design comprises of:
a. a swivel (1) with teeth is pivoted to the palm base (5) using a dowel pin (6), the said swivel moves over a jaw (8).
b. a grub screw (7) is positioned inside the dowel pin (6) to arrest axial movement of the said dowel pin (6) during swivel (1) rotation.
c. a compression spring (4) housed in the palm base (5) ensures that swivel (1) and jaw (8) are locked in certain position;
d. a jaw (8) holding the spring (4) oscillates up and down and keeps the swivel (1) intact to the pivot axis;
e. a thumb finger (10) is associated to the swiveling system through a dowel pin (12), the said dowel pin (12) anchors the thumb finger spring (11) to swivel (1);
f. a housing is arranged to incorporate a bearing (15) and a pivot pin (14) and pivot screw (16) to fix the Thumb finger (10) to swivel (1);
g. a color pallet (3) with three slots t1, t2 and t3 is fixed to the swivel (1) such that the said pallet (3) moves along with the swivel (1), the said color pallet (3) is fixed to swivel (1) with a snap fit;
h. a color sensor positioned on position sense PCB (2) records the reflecting light from slots t1, t2, t3 of color pallet (3) and gives the position feedback of the thumb;
i. a flexible Silicone rubber covering (13) is covered over the swiveling system near the base of thumb finger (10) to protect the mechanical components inside the palm base (5);
j. a position sense PCB (2) is fixed between palm housing and swivel to sense the position of the thumb finger (10); and
k. a microcontroller PCB continuously reads the output of the position sense PCB (2);
Characterized by:

the thumb finger swiveling system (100) is arranged with three locking positions that are adjustable and controlled by the user;
the three locking positions are adjusted by the user and locked to a particular position depending on the object user wishes to hold;
the thumb finger swiveling system (100) is designed with minimum number of components and enables the user to grab objects of various shapes and sizes;
the thumb finger swiveling system (100) is equipped with a position feedback system which is accurate, cost effective, compact in size, easy to manufacture and use.
the designed position feedback system is contactless with rotation mechanism which in turn requires no maintenance in long run; and
the swiveling system designed is completely user input based and gives accurate position locking and can withstand heavy loads.

2. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the position sense PCB (2) is provided with a slot. Wherein, a dowel pin (6) passes through it and a nylon bush (9) is placed between position sense PCB (2) and the swivel (1) so, that the position sense PCB (2) is held firmly.

3. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the position sense PCB (2) output is connected to input pin of a microcontroller PCB which continuously reads the data coming from color sensor present on the position sense PCB (2).

4. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the top end of the swivel (1) has a through hole for incorporating the thumb finger (10) of the bionic hand with suitable fastening elements preferably pivot pin 14 and pivot screw 16.

5. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the assembly design of the swiveling system (100) can be extended to multiple locking positions by increasing number of teeth on the swivel (1).

6. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the color pallet (3) is fixed to swivel (1) with a snap fit, the pallet having three slots t1, t2 and t3 is fixed to the swivel (1) such that the said pallet moves along with the swivel (1).

7. The thumb finger (10) swiveling system (100) according to claim 6, wherein the said slots t1, t2 and t3 are coated with BLUE, GREEN and RED colors respectively.

8. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein upon the swivel (1) movement, the color pallet (3) moves along with the swivel (1), the color sensor present on the position sense board PCB (2) records the reflecting light from the colored slots present on the color pallet and sends the corresponding digital value of color to microcontroller PCB (2) that detects the thumb finger position.

9. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the algorithm running in microcontroller PCB detects the digital return of color sensor corresponding to the slots t1, t2 & t3 and decides the position of thumb finger.

10. The thumb finger (10) swiveling system (100) according to claim 9, wherein the digital return of reflecting light coming from slots t3, t2 & t1 corresponds to locking positions L1, L2 & L3 respectively.

11. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the swivel (1) is proposed to have three locking positions namely L1, L2 & L3 which are attained as mentioned in claim 9 through position sense PCB (2) functioning.

12. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the swivel (1) is initially at locking position L1 (reference position) with swivel (1) teeth and jaw (8) that are engaged from preventing movement of swivel (1) relative to palm base (5).

13. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein on applying rotational force on the swivel (1) in clockwise direction with respect to the reference locking position L1, locking position L2 and locking position L3 are obtained by compression of the spring (4) and the movement of jaw (8) in downward direction.

14. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the user is provided to adjust the thumb finger in multiple locking positions and thereby enables the user to grasp objects of various shapes and sizes.

15. The thumb finger (10) swiveling system (100) as claimed in claim 1, wherein the user can rotate the swivel in anti-clockwise direction to comeback to any required position.