MULTI-GRASPING AND ARTICULATED TRANS-RADIAL PROSTHESIS

Technical Field

[001] The disclosure of the present invention relates to a field of art of providing prosthesis for use by persons with a medical condition. The present application particularly relates to a multi-grasping and articulated trans-radial prosthesis having fingers, metacarpal-phalangeal joints and a wrist.

Background of the invention

[002] Individuals suffering from a medical condition such as an impaired hand, or lack thereof, due to congenital defect or an accident, are generally limited and may not be able to perform simple daily tasks that are easily performed with a normal hand. Simple tasks include holding a writing implement, food item, utensil, personal hygiene and grooming items or other similar devices due to the inability to grasp the device and perform the intended function that the device usually serves. The person may have a strong, supportive upper limb, but the hand, or lack thereof, is unable to hold, grip, or stabilize items necessary to perform normal tasks associated with such devices.

[003] Individuals suffering from trans-radial disability in their arms, prosthetic devices such as i-limb™ ultra are available. However, such prosthetic devices, which are based on neural modality, suffer from issues such as surgical complexity, cost and reliability. Prostheses like i-limb™ ultra performs variety of day to day tasks but are very expensive. i-limb™ ultra requires certain amount of programming during its initial setup, which makes it more complex for a user. Such prosthetic arms fail to address hand movement like wrist deviation, forcing amputee to take awkward position while handling the containers with fluids. As these are myoelectric prosthetic arms, installing these on an amputee requires more skill. Surgical complexity arises in the case of neuro-electric prosthesis. Also power requirements of such devices are high due to more number of electronic devices thus reducing the reliability and end result being heavier prosthesis.

[004] Devices such as plastic hand-forms are also used, which are purely cosmetic in nature and not preferred to for the restoration of functionality of hand.

[005] Therefore, there is a need for a prosthetic hand that is functionally versatile, operationally light and simple, aesthetically natural and economically affordable. Objects of the present invention

[006] The primary object of the present invention is to provide a multi-grasping and articulated trans-radial prosthetic arm for an individual who is in need such prosthesis, having fingers, metacarpal-phalangeal joints and a wrist.

[007] An object of the present invention is to provide a multi-grasping and articulated trans-radial prosthesis, having differential finger movements.

[008] Another object of the present invention is to provide a multi-grasping and articulated trans-radial prosthetic arm, having a hand that can grasp variable-size objects, by means of a single actuator, which is controlled by the muscle movement of an user.

[009] Yet another object of the present invention is to provide a multi-grasping and articulated trans-radial prosthesis, which is not only anthropomorphic but also substantially biofidelic with articulated movements of the fingers and wrist.

[010] It is also an object of the present invention is to provide a multi-grasping and articulated trans-radial prosthetic arm with a hand having a variable grasping force.

[011] Further object of the present invention is to provide a multi-grasping and articulated trans-radial prosthesis that renders a gripping-sense feedback to the user.

[012] Yet another object of the present invention is to provide a multi-grasping and articulated trans-radial prosthesis having a coordinated movement between the elbow and the wrists to maintain a global orientation of the wrist thereby providing a capability to hold and handle containers with liquid.

[013] Still another object of the present invention is to provide a multi-grasping and articulated trans-radial prosthesis with a distal forearm portion having pronation and supination movements.

[014] Yet another object of the present invention is to provide a multi-grasping and articulated trans-radial prosthesis, which can be connected to the arm of a subject without any surgery.

Summary of the invention

[015] A multi-grasping and articulated trans-radial prosthesis having is provided having a movable hand 101, with movable fingers 102a, 102b, 102c, 102d and 102e and a movable wrist 103. A distal-forearm 104 with an arm pulley 105 is connected to the movable hand 101. A movable proximal-forearm 106 having a muscle sensor 107 is connected to the distal-forearm 104 through a rotary joint 108. An upper arm 19 with an elbow pulley 110 is connected to the proximal-forearm 106. An elbow pulley 110 and the ami pulley 105 with a pin 105a are connected by means of flexible connecting members Ilia and 111b. Brief description of the drawings

[016] FIG.l and FIG.1A are perspective views of multi-grasping and articulated trans¬radial prosthetic arm of the present invention.

[017] FIG.2 is a perspective view of prosthetic hand of the multi-grasping and articulated trans-radial prosthetic arm.

[018] FIG.3 is an exploded view of prosthetic finger of the multi-grasping and articulated trans-radial prosthetic arm.

[019] FIG.4a is an exploded view of prosthetic thumb of the multi-grasping and articulated trans-radial prosthetic arm.

[020] FIG.4b is a partial sectional view of prosthetic thumb of the multi-grasping and articulated trans-radial prosthetic arm illustrating the routing for actuation of the thumb. [021] FIG.5a is a perspective view of muscle sensor of the multi-grasping and articulated trans-radial prosthetic arm.

[022] FIG.5b is a circuit drawing illustrating the electrical connections of the multi-grasping and articulated trans-radial prosthesis.

[023] FIG.6a and FIG.6b are perspective views of the finger movements (finger and thumb) of the multi-grasping and articulated trans-radial prosthetic arm.

[024] FIG.7 is a perspective view of the hand of the multi-grasping and articulated trans¬radial prosthetic arm, illustrating differential finger movements while holding an object.

[025] FIG.8 is perspective view of multi-grasping and articulated trans-radial prosthetic arm holding an object at variable positions by maintaining the orientation of the object. Description of the invention

[026] In human fore arm, pronation and supination actions refer to the rotation of the forearm at the radioulanar joint. In pronation, radius carrying the arm turns anteromedially and obliquely across the ulna, its proximal end remains lateral and distal becomes medial. Whereas, in supination, the radius returns to a position lateral and parallel to the ulna. Muscles of the arm that pronate the forearm are pronator teres and pronator quadratus. The muscles that supinate the forearm are biceps brachii and supinator muscle. Many day to day activities involve pronation and supination of hand-like turning the knobs, eating, lifting flat objects, etc. This motion of hand is required to perform tasks, which serves basic needs. However, an individual suffering from transradial amputation normally loses pronator quadratus muscle and distal radioulnar joint. However, on account of proximal radioulnar joint, pronator teres muscle, biceps brachii muscle and supinator muscle, individual can still pronate and supinate residual stump of the fore arm. This capability of individual is used to pronate and supinate the prosthetic device of the present invention.

[027] Accordingly, the present invention provides a multi-grasping and articulated trans-radial prosthetic arm for transradial amputees, which is connected to the residual stump of the fore arm. The prosthesis of the present invention is not only anthropomorphic but also substantially biofidelic having the articulated movements of natural fingers and wrist. The articulation of all the parts of the multi-grasping and articulated trans-radial prosthesis of the present invention is more mechanical in nature, thus eliminating the need for incorporating digital processors and reducing the cost of the prosthetic device.

[028] As shown in FIG.l, initially, the primary prosthetic components of the multi- grasping and articulated trans-radial prosthesis 100 of the present invention are described. The multi-grasping and articulated trans-radial prosthesis 100 includes a movable hand 101 to which movable fingers 102a, 102b, 102c, 102d and 102e are connected. The finger 102a corresponds to natural little finger of a human subject, the finger 102b corresponds to the natural third finger, the finger 102c corresponds to the natural middle finger and the finger 102d corresponds to the natural index finger and whereas the finger 102e corresponds to the natural thumb. The movable hand 101 is connected to a movable wrist 103 and to receive the wrist movements from the connected movable wrist 103. A distal-forearm 104 with at least an arm pulley 105 is connected to the movable hand 101, through the movable wrist 103. The arm pulley 105 is pivoted to distal-forearm 104 so as to rotate in clockwise and counter clockwise directions. In this exemplary aspect, a single arm pulley 105 is shown.

However, the number of arm pulleys 105 can be suitably increased depending on the required rotational features of the arm. A movable proximal-forearm 106 with at least a muscle sensor 107 is connected to the distal-forearm 104 through a rotary joint 108. An upper arm 109 with an elbow pulley 110 is connected to the proximal-forearm 106. The elbow pulley 110 and arm pulley 105 are connected through flexible connecting members Ilia and 111b. The elbow pulley 110 is pivoted to distal-forearm 104 so as to rotate in clockwise and counter clockwise directions, in response to the elbow movements of the subject. The upper arm 109 is used to connect the prosthesis 100 to an upper arm of the human subject having a residual stump portion due to amputation of a fore arm shown in FIG.l. The upper arm 109 of the prosthesis 100 is mounted on the upper arm of the subject and firmly connected to the body of the subject through straps or belts.

Once the upper arm 109 is mounted, the corresponding movable proximal-forearm 106 is also mounted on the stump portion of the forearm of the subject. In this arrangement, the prosthesis takes the natural orientation of the elbow and forearm of the object and snugs comfortably on the arm portion of the subject, so that the muscle sensor 107 comes in physical contact with the muscles of the stump portion of the fore arm of the subject. The prosthesis 100 thus mounted on the fore arm of the subject is arranged to move along the forearm and elbow movements of the subject. Thus, as shown in FIG.l, the movable fingers 102a, 102b, 102c, 102d and 102e of the movable hand 101, which are connected to inter alia, the movable wrist 103, movable proximal-forearm 106, the distal- forearm 104 and the upper arm 109, are configured to orient along the wrist and arm movements of the subject, while gripping an object.

[029] Now, specifically referring to FIG.la, the multi-grasping and articulated trans- radial prosthesis 100, is shown in fully covered condition. The movable hand 101 is provided with a cover 113. The cover 113 can be made of any suitable material, such as fabric, plastic or metal that can render a sensory and aesthetic feel. Similarly, the movable fingers 102a, 102b, 102c, 102d and 102e, particularly the end portions of the fingers can also be provided with pads made of soft material such as polymer or rubber.

[030] Hitherto, the broad constructional features of the multi-grasping and articulated trans-radial prosthesis 100 are described. Now referring to FIG.2 of the accompanied drawings, the various components of the prosthetic movable hand 101 are now described in detail. As shown in FIG.2, a palm member 112 is arranged as a base for the movable hand 101. The palm member 112 in this embodiment is exemplarily shown as a hollow plate, which is configured to mimic a palm of a human hand and forms housing for other components of the movable hand 101. The palm member 112, in this exemplary embodiment is shown as a metallic plate. It is however, understood here that any another suitable material such as metal alloys, polymer can also suitably used for preparing the palm member 112. The material that is used for making the palm member 112 can be rigid or flexible.

[031] A slot 112a is arranged at the proximal end of the palm member 112. The slot 112a is advantageously a narrow slit extending from the peripheral end of the palm member 112 and terminates towards the central portion of the palm member 112. The slot 112a while extending from the peripheral end of the palm member 112 is configured to elevate gradually so as form a slope.

[032] A finger actuator assembly 114 is arranged on the palm member 112 as shown in FIG.2. The finger actuator assembly 114 actuates the movements of the movable fingers 102a, 102b, 102c, 102d and 102e. The finger actuator assembly 114 includes a prime mover 114a. The prime mover 114a can be one of hydraulic motor, piston, electric motor, linear actuator etc., which is connected to a power source 147. In this exemplary embodiment the prime mover 114a is provided with a movable piston, having linear fore and aft movements along the bottom surface of the palm member 112. Therefore, the finger actuator assembly 114 renders linear movements to the other sub-assemblies of the palm member 112.

[033] A flexible member 114b is connected to the distal end of the prime mover 114a through one end of the biasing member 114c, as shown in FIG.2. The terminal end of the flexible member 114b is connected to one end of the biasing member 114c and the other end of the biasing member 114c is hooked on to a pin or fastened to the pin, which is permitted to pass through the distal end of the prime mover 114a. In this exemplary embodiment the flexible member 114b is shown as a cable, string or a wire, having tensile characteristics and whereas the biasing member 114c is a spring or an elastic member. In this arrangement the biasing member 114c is configured to compress and stretch corresponding to the linear movements of the prime mover 114a.

[034] The flexible member 114b, which is connected to biasing member 114c is further extended over a palm pulley 136 and connected to one end of a primary horizontal link 115, as shown in FIG.2. The primary horizontal link 115 is a movable link provided with a swiveling action along its vertical axis. The other end of the primary horizontal link 115 is connected to another flexible member 119e through another pulley and connected to bottom portion of the palm member 112 in proximity to the finger 102e mounting area, as shown in FIG.2. Therefore, on actuation of the prime mover 114a the primary horizontal link 115 is pulled towards the proximal end of the palm member 112 by the flexible member 114b. The primary horizontal link 115 is a longitudinal member, which distributes the pulling force exerted by the flexible member 114b, uniformly, to all fingers 102a, 102b, 102c, 102d and 102e.

[035] Guides 137, which are vertical structures, such as screws, rivets, pins, blocks, etc, are mounted on the central portion of the palm member 112. In this embodiment, pair of guides 137 are shown that are arranged adjacent to each other on the palm member 112. A primary vertical link member 116 is mounted on the guides 137 through a slot 138. The primary vertical link member 116 moves vertically in the space as provided in the form of the slot 138. The movable primary horizontal link 115 is pivoted to the movable primary vertical link member 116, as shown in FIG.2. Accordingly, in this arrangement, the vertical movement of the primary horizontal link 115 causes the vertical or the swiveling movement of the primary vertical link member 116.

[036] In another aspect of the present invention, a secondary horizontal link 117 is pivoted at the distal end of the primary vertical link member 116. The secondary horizontal link 117 is also a movable member and is advantageously shown as extending on either side of the primary vertical link member 116. The primary vertical link member 116 moves or swivels in the vertical direction along with the movement of the primary vertical link member 116.

[037] Tertiary horizontal links 118a and 118b are pivoted to the secondary horizontal link 117 on either side of the vertical axis of the primary vertical link member 116. Tertiary horizontal links 118a and 118b are arranged to move vertically or swivel along with the movement of the secondary horizontal link 117.

[038] Flexible elongated members 119a and 119b are connected to the tertiary horizontal link 118a and whereas flexible elongated members 119c and 119d are Connected to the tertiary horizontal link 118b.

[039] In an aspect of the present invention the flexible members are made of but not limited to plastic cord, metal cord, fabric cord and a combination of these materials. The links in this arrangement are advantageously made of metals and these can also suitably made of other materials such as polymers.

[040] In another aspect of the present invention, as shown in FIG.3, the constructional features of the fingers 102a, 102b, 102c and 102d, are now described. It is to be noted here that the constructional features of the fingers 102a, 102b, 102c and 102d are advantageously shown as identical structures. The finger 102a includes a mounting lug 120, which is mounted on the distal portion of the palm member 112. The mounting lug 120 is provided with pathways 120a and 120b, which are separated by a separator. A proximal link 122, which is a movable and elongated member, with its one end arranged in the pathway 120a and connected to the mounting lug 120 by means of a pin 120c. A proximal phalange member 121, which is a movable member, with its one arranged in the pathway 120b and connected to the mounting lug 120 by means of pin 120d. An intermediate phalange member 123, with pathways 123a and 123b that are separated by a separator, is movably connected the proximal phalange member 121 and the proximal link 122, through pins 120e and 120f, as shown in FIG.3.

A distal phalange member 124 is movably connected to the intermediate phalange member 123 through the pin 120g. A distal link 125 is connected to the distal phalange member 124 with its one end through pin 120i and other end of the distal link 125 is connected to the proximal phalange member 121 though pin 120g. The articulation of the phalange members, which movably pivoted on the lug, is effected by respective movements of links and pins. For the sake of brevity, constructional features of fingers 102b, 102c and 102d are identical with the constructional features of the finger 102a as shown in FIG.3 and hence not described again.

[041] In another aspect of the present invention the constructional features of movable finger 102e, which corresponds to the thumb of the human hand are now described, by referring to FIG.4a and FIG.4b. The movable finger 102e includes brackets 126 and 128, having pass-through holes 126a and 128a, which are separated by an intervening space between them. The bracket 126 is provided with locking pits 127, which are spatially arranged around the pass-through hole 126a. The bracket 126 is mounted on the palm member 112 as shown in FIG.2. A movable metacarpal phalange 131 with a movable hollow shaft 129 loaded with a biasing spring 130, and a pulley 131a, is connected to the brackets 126 and 128. A locking protrusion 132 is arranged on the metacarpal phalange 131, which is defined to enter into the respective locking pits 127, during the course of the movement of the movable finger 102e. The movable metacarpal phalange 131 is provided with pathways 131b and 131c that are separated by separators. The pathways 131b and 131c are used to connect movable proximal thumb phalange 133 and link 135, through a pin 131d and 131e and a spring 133a. A distal thumb phalange 134 is connected to proximal thumb phalange 133 through a pin 134a. The other end of the link 135 is connected to the distal phalange 134 through a pin 134b.

[042] Now again referring to FIG.2, the connectivity of the movable fingers 102a, 102b, 102c, 102d and 102e to the primary vertical link 116 through the tertiary horizontal links 118a and 118b, movable primary horizontal link 115, and the primary vertical link member 116 is now described. The movable finger 102a is connected to one end of the tertiary horizontal link 118a by means of the flexible member 119a and whereas the movable finger 102b is connected to the other end of the tertiary horizontal link 118a through the flexible member 119b, as shown in FIG.2. In this arrangement the articulation of the movable fingers 102a and 102b can be effected differentially, by actuating the movement of the tertiary horizontal link 118a. Similarly the movable finger 102c is connected to one end of the tertiary horizontal link 118b by means of the flexible member 119c and whereas the movable finger 102d is connected to the other end of the tertiary horizontal link 118b through the flexible member 119d, as shown in FIG.2. In this arrangement the articulation of the movable fingers 102c and 102c can be effected differentially, by actuating the movement of the tertiary horizontal link 118b. Therefore, movable fingers 102a, 102b, 102c, 102d can be articulated, differentially, in order to hold an object. Whereas, the movable finger 102e, which is connected to the movable primary horizontal link 115 is articulated by means of the connecting member 119e. Therefore, the articulation of the movable fingers 102a, 102b, 102c, 102d and 102e are performed by the single prime mover 114a.

[043] Now referring to FIG.l, the constructional features of the arm portion of the multi-grasping and articulated trans-radial prosthesis 100 of the present invention are described. A distal-forearm 104, which is a hollow member, is provided with a substantially circular portion at its proximal end. The distal-forearm 104 is tapered towards as it progresses towards its distal end so that the profile of the distal-forearm 104 substantially matches with the natural arm profile of the subject. The movable hand 101 is connected to the distal end of the distal-forearm 104 through the wrist 103.

[044] Now referring to FIG.l, an upper arm 109 is movably connected to the proximal end of the proximal-forearm 106 through the elbow pulley 110. The flexion and extension movements of the proximal-forearm 106 are accomplished through the incorporation of the elbow pulley 110. The elbow pulley 110 and the arm pulley 105 are connected by means of flexible connecting members Ilia and 111b, which are cables. The cables are in flow communication with the pulleys 110 and 105. The cables are arranged in respective sheaths and move along the longitudinal axes of the proximal and distal-forearms 106 and 104, consequent movement of the flexion and extension movements of the proximal-forearm 106. The pulleys are configured to rotate in clockwise and counterclockwise directions, in response to the flexion and extension movements of the proximal-forearm 106. A pin 105a is connected to the arm pulley 105, which also rotates along with the movement of the arm pulley 105. The pin 105a is movably placed in the slot 112a (FIG.2) of the palm member 112.

[045] The proximal-forearm 106, which is a hollow member, is connected to the distal- forearm 104 through a rotary joint 108, as shown in FIG.l. The rotary joint 108, as shown in the magnified portion of FIG.l, includes a ring portion and a socket portion, which are rotatably meshed to render a rotary connectivity between the proximal-forearm 106 and distal-forearm 104. By incorporating this meshing arrangement, the pronation and supination movements of distal-forearm 104 are performed.

[046] The constructional features of the aforementioned muscle sensor 107 are now described, by specifically referring to FIG.5 and FIG.l. The muscle sensor 107, which is a circular ring member 139, is mounted on the residual stump portion 140 of the subject so that its inner surface 141 abuts the top surface of the stump portion 140 and senses the tightening and relaxing of the muscles of the stump portion 140. The circular ring member 139 is made of flexible material so that ring contracts and expands in response to the tightening and relaxing of the muscles of the stump portion 140. The one end of the circular ring member 139 is terminated with an end portion 142 and the other end of the circular ring member 140 is terminated with an end portion 143. A toggle switch 144 and a contact switch 145 are mounted on end portion 143 are connected to the end portion 142 through a connectors 144a and 145a. End portions 142 and 143 of circular ring member 139 are physically separated from each other while it is mounted on stump portion 140.

[047] As shown in FIG.5a, which is circuit drawing, depicting switch-on and switch- off modes of the toggle switch 144 and contact switch 145 of the circular ring member 139 that is used to actuate the hand movements of the multi-grasping and articulated trans¬radial prosthesis 100.

[048] A feedback member 146, which is preferably a pin or strip, is connected to the inner periphery of the distal-forearm 104 and abutted to the stump 140. The one end of the feedback member 146 is connected to the flexible member 146a, which is enclosed in a sheath 146b. The flexible member 146a that is originating from the feedback member 146 is connected to the prime mover 114a and the corresponding sheath 146b to the biasing member 114c.

[049] In yet another aspect of the present invention, the functional aspects of the multi-grasping and articulated trans-radial prosthesis are now described. The broad functions that can be performed by the of the multi-grasping and articulated trans-radial prosthesis include, actuation of multi-grasping and articulated trans-radial prosthesis, articulation of segmented fingers, gripping of an asymmetric object using the fingers, application of variable force, deviation movements of the wrist & and flexion and extension movements of the proximal forearm, pronation and supination movements of the distal forearm and feedback of the applied force.

[050] Now referring to FIG.l and FIG.2 the multi-grasping and articulated trans- radial prosthesis is mounted on the stump portion and the upper arm of the subject respectively. The subject tightens the muscles of the stump portion, which results in the expansion of the circular ring member 139, illustrated in FIG.5a, which in turn closes the contact switch 145 thereby initiating forward motion of the prime mover 114a. The forward motion of the prime mover 114a pulls or drags the biasing member 114c, which in turn pulls or drags the flexible member 114b that is connected to the primary horizontal link 115. The primary horizontal link will now displace towards the proximal end of the palm member, by carrying along with it the primary vertical link member 138. The primary vertical link member also will drag the secondary horizontal link 117 vertically downwards towards the proximal end of the palm member. This downward pull of the secondary horizontal link 117 pulls the tertiary horizontal links 118a and 118b downwards. Consequently, the tertiary horizontal links pull the flexible elongated members 119a, 119b, 119c, 119d that are connected to the movable fingers 102a, 102b, 102c and 102d, resulting articulation movement of the fingers as shown in FIG.6a.

Simultaneously, the primary horizontal link 115 pulls the flexible elongated member 119e that is connected to the movable proximal thumb phalange 133 of the thumb 102e, pulling the movable proximal thumb phalange 133, which in turn articulates the thumb. Now referring to FIG.7, once one of the fingers comes in contact with an object that is held by the subject, the movement of that particular finger is stopped. However, the other remaining fingers continue to move, differentially, by means of the rotary movements rendered by primary, secondary and tertiary horizontal links 115,117 and 118a, 118b, till all other fingers come in contact with the object. Even though, the movements of the fingers are halted, the prime mover 114a nevertheless continues to move thereby expanding the biasing member 114c, resulting in the application of enhanced force on the object.

[051] In case, subject prefers to stop the movement of the fingers, the muscles of the stump portion are relaxed causing contraction of the circular ring member 139 or circular ring member 139 attains its previous or normal status, resulting in switching off of the contact switch 145. In this pause position grip on the object is maintained in this position.

[052] In order to release the grip on the object, the subject tightens the muscles of the stump portion, even more intensely, resulting in the actuation of the toggle switch 144 thereby reversing the polarity as illustrated in FIG.5b and causing the prime mover 114a to move in reverse direction thus releasing the grip on the object.

[053] Now referring to FIG.6B, the opposition & apposition movement of the thumb 102e is crucial in gripping the object. The position of the thumb vis-a-vis other fingers is manually positioned by moving the thumb. The movable hollow shaft 129 is displaced longitudinally by pushing the metacarpal phalange 131 towards the central portion of the palm member thereby releasing the locking protrusion 132 from the corresponding locking pit 127. Once the desirable position of the thumb is reached the locking protrusion is locked in another locking pit as provided at a different location by the actuation of the biasing member 130. This function facilitates the opposition and apposition movements of the thumb.

[054] Now Referring to FIG.l, the multi-grasping and articulated trans-radial prosthesis of the present invention also provides a feed back to the subject. In other words, it communicates the extent of grip of the object to the subject. Once the subject grips the object with the fingers, the intensity of the grip, increases by virtue the expansion of the biasing member 114c of the finger actuator assembly 114. The string 146a, which is connected to the distal end of the biasing member 114c, is pulled from the sheath 146b, which is connected to proximal end of the biasing member 114c, resulting in pulling of the feedback member 146, which applies pressure on the stump portion, which will be proportional to the applied force.

[055] The pronation and supination of the distal forearm is effected by the rotation of the residual stump portion of the subject.

[056] The deviation of the hand is performed by moving the proximal forearm with respect to the upper arm resulting in the rotation of the elbow and arm pulleys by the action of the flexible connecting members. The pin of the arm pulley which is movably placed in the slot of the palm member also moves in the slot, causing the deviation of the hand with respect to distal forearm, as illustrated in FIG.8.

[057] Accordingly, the present invention provides a multi-grasping and articulated trans-radial prosthesis, which can be connected to the arm of a subject without any surgery. The prosthesis of the present invention is a mechanical device without any electronics leading to the reliability and easy maintenance of the prosthesis. The movable fingers of the prosthesis adapts to any shape of the object that is being gripped by its hand and provides a feedback to the user for grasping and for application of more force when required. The movable had of the prosthesis is provided fingers with an equal force distribution and means of achieving multi-segmented finger movement. The prosthesis of the present invention is provided with multi-grasping capacity of 5 to 100 mm pinch power grasp capability, having a variable gripping force. The prosthesis of the present invention is provided with a mechanically-controlled wrist orientation to allow handling of containers with liquids. In the prosthesis of the present invention a single actuator is used for achieving multi-segmented and multi-grasp capability.

[058] It is also understood that the following claims are intended to cover all the generic and specific features of the invention herein described and all statements of the scope of the invention, which as a matter of language might be said to fall there between.

We Claim:

1. A multi-grasping and articulated trans-radial prosthesis, comprising: a movable hand 101, with movable fingers 102a, 102b, 102c, 102d and 102e, operably connected to a wrist 103; and a distal-forearm 104 with at least an arm pulley 105, operably connected to the movable hand 101 through the wrist 103; a movable proximal-forearm 106 with at least a muscle sensor 107, operably connected to the distal-forearm 104 through a rotary joint 108; an upper arm 109 with an elbow pulley 110, operably connected to the proximal-forearm 106;and the elbow pulley 110 and the arm pulley 105 with a pin 105a are operably connected by means of flexible connecting members Ilia and 111b.

2. The prosthesis as claimed in claim 1, wherein the movable hand 101 further comprising: a palm member 112 with a slot 112a, covered with a palm cover 113; a finger actuator assembly 114 disposed on the palm member 112; a movable primary horizontal link 115 operably connected to the finger actuator assembly 114 and the finger 102e by means of a flexible member 119; a movable primary vertical link 116, movably disposed in the central portion of the hollow palm member 112 and connected to the movable primary horizontal link 115 and arranged to move in linear direction; a movable secondary horizontal link 117 operably connected to the primary vertical link member 116, and a plurality of movable tertiary horizontal links 118a and 118b, operably connected to the movable secondary horizontal link 117. the movable tertiary horizontal links 118a and 118b, operably connected to movable fingers 102a, 102b, 102c, 102d, by means of flexible members 119.

3. The prosthesis as claimed in claim 1, wherein the movable finger 102e further comprising: a bracket 126 with locking pits 127 is connected to a bracket 128 with an intervening gap; a movable hollow shaft 129 with biasing member 130, is disposed between the brackets 126 and 128; a metacarpal phalange 131 with a locking protrusion 132, operably connected to the brackets 126 and 128 through the movable hollow shaft 129; and a proximal thumb phalange 133 is operably connected to the metacarpal phalange 131; and a distal thumb phalange 134 is operably connected to a proximal thumb phalange 133; and a link 135 is disposed between the distal thumb phalange 134 and the metacarpal phalange 131.

4. The prosthesis arm as claimed in claim 1, wherein movable fingers 102a, 102b, 102c, 102d and 102e further comprising: a plurality of mounting lugs 120 with intervening gaps, disposed at the distal end of the palm member 112; a plurality of movable proximal phalange members 121 operably connected to the mounting lugs 120; a plurality of proximal links 122 arranged in parallel to the proximal phalange members 121 and operably connected to the mounting lugs 120; a plurality of intermediate phalange members 123 operably connected to the movable proximal phalange members 121 through the proximal links 122; and a plurality of distal phalange members 124 operably connected to the intermediate phalange members 123 and to distal links 125; distal links 125 are connected proximal phalange members 121.

5. The prosthesis as claimed in claim 1, wherein the distal-forearm 104 is hollow and rotatable.

6. The prosthesis as claimed in claim 1, wherein a movable pin operably connected to the arm pulley 105.

7. The prosthesis as claimed in claim 1, wherein at least a feedback member 146 is disposed on the distal-forearm 104.

8. The prosthesis as claimed in claim 1, wherein the muscle sensor 107 is a ring, strip or a plate.

9. The prosthesis as claimed in claim 1, wherein the flexible connecting member Ilia and 111b is a string, cable or a wire, enclosed in a sheath.

10. The prosthesis as claimed in claim 1, wherein the elbow pulley 110 and the wrist pulley 105 disposed to rotate in clockwise and counterclockwise directions.