GB2498788A - An artificial wrist component - Google Patents

Abstract

An artificial wrist component 10 comprising a moveable portion 12 which at least in part defines a central through-hole 16 in the component 10 defining an axis thereof and which is engaged by a selectively adjustable tightener 48 in such a fashion that adjustment of the tightener 48 moves the moveable portion 12 to reduce the cross-section of the through-hole 16. The said moveable portion 12 is provided by a first part of the component 10. A second part 14 of the component surrounds the first part 12. The said selectively adjustable tightener 48 extends through respective portions of both.

Description

An artificial wrist component [0001] The present invention relates to an artificial wrist component comprising a moveable portion which at least in part defines a central through-hole in the component defining an axis thereof and which is engaged by a selectively adjustable tightener in such a fashion that adjustment of the tightener moves the moveable portion to reduce the cross-section of the through-hole.

[0002] Such a component has hitherto been laminated to the distal end of a forearm prosthesis. This has been effected after an artificial hand has been mounted on the component by way of a plate secured to a proximal end of the artificial hand, the plate having a screw-threaded shank extending away from the plate on the side thereof further from the artificial hand and the shank extending through the through-hole in the wrist component, the tightener being used to secure the shank in the artificial wrist component.

[0003J A disadvantage of such a previous construction is that batteries required for the operation of the artificial hand have been used in an expensive construction of the forearm prosthesis requiring inner and outer skins thereof to provide a cavity for the batteries.

[0004] The present invention seeks to provide a remedy.

[0005] Accordingly, the present invention is directed to an artificial wrist component having the construction set out in the opening paragraph of the present specification, in which the said moveable portion is provided by a first part of the component, a second part of the component surrounds the first part, and the said selectively adjustable tightener extends through respective portions of both the said first arid second parts.

100061 Preferably the component is generally disc-shaped.

[00071 It is desirable to have the moveable. portion arcuate, and preferably resilient.

[0008] Advantageously the said first part is made ofa synthetic plastics material.

[00091 Advantageously the said second part is made of a metallic material.

[0010] The said first part may be held against axial displacement relative to the said second part by means of respective lobes. Both parts may be provided with a plurality of such lobes. Preferably the lobes of the second part are located outside the lobes of the said first part. During assembly however, each lobe of the first part may be positioned between two lobes of the said second part, and visa versa, so that the lobes of the first part interdigitate with the lobes of the second part so that the said first part may be inserted into the said second part in an axial direction whereafter the said first part can be rotated relative to the said second part about the axis of the said through-hole to bring the lobes of the said first part into registration with the lobes of the said second part, so that the said first and second parts are no longer displaceable relative to one another in an axial direction.

[0011] Resilient plastics portions may be provided on the lobes of one of the said first and second parts, preferably on the said first part, to eliminate the possibility of any rattle between the first and second parts.

[00121 A bolt may be inserted in respective cavities of the said first and second parts which are in alignment with one another when the lobes of the said first and second parts are in registration with One another; to inhibit relative rotation between the first and second parts about the axis of the said through-hole.

[0013] The said selectively adjustable lightener may comprise a bolt which extends transversely of the axis of the said through-hole. through portions of the said first and second parts. Preferably the bolt of the selectively adjustable tightener extends through the bolt which inhibits relative rotation between the said first and second parts.

[0014] A connecting part with a shank portion may be provided on one side of the said artificial wrist component, with the shank portion held in the said through-hole of the said first part. An artificial hand may be attached to the connecting part by means of screws.

[00151 The said second part may be may be in the form of a ring, and may be laminated to a distal end of a forearm prosthesis. The latter may be hollow and may house batteries accessible by removal of the said first part from the said second part.

[0016] An example of an artificial wrist component made in accordance with the present invention will now be described in greater detail with reference to the accompanying drawings, in which: [00171 Figure 1 shows a perspective side view of parts of the component at an early stage in their assembly; [00181 Figure 2 shows a corresponding view of the parts shown in Figure 1 in a subsequent stage of the assembly of the component; [0019] Figure 3 shows a view corresponding to the view of Figures 1 and 2, of the parts shown therein, with a further part located ready for insertion in the parts shown in Figures 1 and 2; [0020] Figure 4 shows a perspective view of the parts shown in Figure 3 from the other side, with the part introduced at Figure 3 being fully inserted; [00211 Figure 5 shows a view corresponding to Figure 4 with a further part located ready for insertion into the rear side of one of the parts shown in Figure 1; [00221 Figure 6 shows the parts shown in Figure.5 viewed in the direction corresponding to that of Figures 1 to 3 with yet a further part located ready for insertion; [00231 Figure? shows a see-through view of the part shown in Figure 6 with the part introduced at the stage shown in that Figure being fully inserted into the component to complete assembly thereof; [00241 Figure 8 shows a perspective side view of a further component to be used in conjunction with the component shown in Figure 7; and [00251 Figure 9 shows a perspective side view of a forearm and hand prosthesis incorporating a wrist component as shown in Figures 1 to 7 as well as a component as shown in FigureS and a battery.

[0026] An artificial wrist component 10 shown in Figures 1 to 7 comprises a first part in the form of a generally disc-shaped plastics moulded core 12 surrounded by a second part constituted by a metallic ring 14. The part 12 is formed with a central 12.7mm (1/2 inch) diameter or size M12 screw-threaded through-hole 16 of generally circular cross-section and having a central axis generally at right angles to the plane of the disc.

[0021 The part 12 is also formed with a through-slot 18, which as viewed in a section through the disc which is at right-angles to its axis, has a first portion 20 opening out into the hole 16 and extending radially outwardly therefrom, from which the slot 18 curves into an arcuate portion 22 which is located inwardly of the periphery of the disc. The acuate portion 22 extends through an angle about the axis of the disc which is between 2u/3 radians and it radians. The portion 22 is thus constituted by an arc centred on the central axis of the disk part 12 and correspondingly the through-hole 16.

[00281 The hole 16 and the slot 18 thereby define an internal arcuate tongue portion 24 of the part 12 which portion, by virtue of the resilience of the synthetic plastics material from which the part 12 is made, is moveable, so that the radial portion 20 of the slot 18 may be reduced to make a corresponding reduction in the cross-sectional size of the through-hole 16.

[0029] The part 12 is also formed with a recess 26 which extends inwardly from the periphery of the disc part 12 in a general direction which is tangential relative to a cross-section of the through-hole 16.

[00301 Five lobes 28 project outwardly from the periphery from the disc part 12 and are spaced apart therearound at uniform intervals, although only three of the lobes 28, for example, are visible in Figure 1.

[0031] A cylindrical recess 30 shown in Figures 4, 5 and 7 opens out at a rear face of the disc part 12 and extends inwardly therefrom, A bore 32 formed within the disc part 12 extends between and opens out into the recesses 26 and 30, and extends generally tangentially of the through-hole 16, and therefore has portions on both sides of the radially outwardly extending portion 20 of the slot 18.

[00321 As can be seen from Figure 4, further recesses 34 are formed in the rear of the disc part 12 so that the latter is generally hollow, to reduce the amount of plastics material in and therefore the cost of the disc part 12.

[0033J The ring part 14 forms a close fit with the disc part 12 and is formed with a through-hole 36 which extends from a periphery of the part 12 to an inner surface thereof, and is in registration with the recess 26 of the part 12 when the artificial wrist component 10 is fully assembled.

[00341 The ring part 14 is also provided on its inner periphery with a set of five inwardly projecting rear lobes 40 spaced apart around the axis of the disc part 12.

[00351 The ring part 14 is also formed with an outwardly extended flange 38 from an inner side of which extends in an inward direction, five front lobes 42 spaced apart around the inner periphery of the flange 38.

[0036] The rear lobes 40 and the front lobes 42 are in registration with one another.

[00371 The two parts 12 and 14 are assembled together to create an artificial wrist component 10 in the following manner.

[0038] Firstly, the lobes 28 are located between the lobes 40 of the ring part 14, and the part 12 is moved axially into the ring 14.

[00391 The part l2is then rotated by 300 about its axis within the ring 14 until each lobe 28 is sandwiched between a pair of lobes 40 and 42 of the ring part 14.

This also brings the recess 26 into registration within the through-hole 36. The fronts of the two parts 12 and 14 are now flush with one another.

[0040J A through-hole barrel bolt 44 is then inserted through the through-hole36 into the recess 26, the short bolt 44 being of sufficient length nonetheless so that when it is pushed fully home into the recess 26, an outer portion of the bolt 44 is located within the through-hole 36.

[0041] A barrel nut 46 is inserted into the recess 30 and an elongate bolt 48 is inserted through the hollow barrel bolt 44, through the bore 32 and into screw-threaded engagement with the barrel bolt 46. A head 50 of the bolt 48 is received in the hollow barrel bolt 44. The head 50 is formed with a recess of hexagonal cross-section so that it may be engaged by an Allen® key.

[0042] This completes the assembly of the artificial wrist component.

[00431 Further assembly of a forearm prosthesis with hand as shown in Figure 9 is effected as follows.

[0044] Firstly a disc plate 60 is provided having connecting through-holes 62 and a ridged central screw-threaded shank portion 64 extending away from the plane of the disc plate 60. A hand prosthesis 66 is secured to the disc plate 60 by means of screws through the connecting through-holes 62.

[00451 A hollow plastics prosthetic forearm 68 in the interior of which are provided batteries 70 is now laminated to the periphery on the ring part 14 of the artificial wrist component 10 around the periphery thereof. The purchase of the laminating material on the ring part 14 is facilitated by keying 72 on the periphery of the ring part 14. During the lamination process, the head 50 of the bolt 48 is kept clear of laminating material so that it is not obscured thereby.

[0046J Next, the shank 64 is inserted into an intended front side of the artificial wrist component 10, into the through-hole 16 so that the shank 64 and the through-hole 16 are co-axial.

[0047] Rotation of the bolt 48 by means of insertion of an Allen® key in the head moves the tongue portion 24 of the disc part 12 so that the gap between the end of that part and the rest of the disc part 12, constituted by the portion 20 of the slot 18, is reduced, and with it the cross-sectional size of the through-hole 16.

The disc part 12, and with it the whole of the artificial wrist component 10 thereby clamps firmly on the shank portion 64 of the disc plate 60 so that the hand prosthesis 66 is rigidly secured to the artificial. wrist component 10.

Adjustment of the bolt 48 by an Allen® key adjusts the frictional engagement between the shank portion 64 and the disc part 12. With a sufficiently low frictional engagement, the relative angular position of the hand 66 and forearm 68, and the relative positions thereof in an axial direction, can be adjusted by relative rotation between the hand 66 and forearm 68 by virtue of the engagement between the screw threads on the shank portion 64 and the disc part 12; [0048] Resilient plastics portions (not shown) provided on and integral with the lobes 28 of the disc part 12 engage the lobes 40 of the ring part 14, and are bent thereby to inhibit raffle between the parts 12 and 14bf the artificial wrist component 10.

[0049] Access to the interior of the plastics prosthetic forearm 68 can now be effected without any destruction of the skins of that forearm. More especially, the bolt 48 can be removed, the shank 64 slid out from the through-hole 16, whereafter the barrel bolt 44 can be removed, and the inner part 12 rotated about its axis until the lobes 28 of the disc part 12 interdigitate with the lobes 42 of the ring part 14, whereupon the disc part 12 can be slid out from the ring part 14 to afford access to the interior of the plastics prosthetic forearm 68, for example to enable replacement of the batteries 70.

[00501 Numerous variations and modifications to the illustrated artificial wrist component may occur to the reader without taking it outside the scope of the present invention. To give one example only, a larger number or alternatively a fewer number of lobes may be provided on the disc part 12 and the ring part 14.

Instead of each lobe 28 on the disc part 12 being sandwiched between a respective pair of lobes 40 and 42 on the ring part 14, lobes may be provided on the ring part 14 each sandwiched between a respective pair of lobes on the disc part 12.

Claims (1)

1. <claim-text>Claims: 1. An artificial wrist component comprising a moveable portion which at least in part defines a central through-hole in the component defining an axis thereof and which is engaged by a selectively adjustable tightener in such a fashion that adjustment of the tightener moves the moveable portion to reduce the cross-section of the through-hole, in which the said moveable portion is provided by a first part of the component, a second part of the component surrounds the first part, and the said selectively adjustable lightener extends through respective portions of both the said first and second parts.</claim-text> <claim-text>2. An artificial wrist component according to claim 1, in which the component is generally disc-shaped.</claim-text> <claim-text>3. An artificial wrist component according to claim I or claim 2, in which the moveable portion is arcuate.</claim-text> <claim-text>4. An artificial wrist component according to any preceding claim, in which the moveable portion is resilient.</claim-text> <claim-text>5. An artificial wrist component according to any preceding claim, in which the said first part is made of a synthetic plastics material.</claim-text> <claim-text>6. An artificial wrist component according to any preceding claim, in whiEh the said second part is made of a metallic material.</claim-text> <claim-text>7. An artificial wrist component according to any preceding claim, in which the said first part is held against axial displacement relative to the said second * r * part by means of respective lobes.</claim-text> <claim-text>8. An artificial wrist component according to claim 7, in which both parts are provided with a plurality of such lobes.</claim-text> <claim-text>9. An artificial wrist component according to claim 8, in which the lobes of the second part are located outside the lobes of the said first part.</claim-text> <claim-text>10. An artificial wrist component according to claim 9, in which during assembly each lobe of the first part is positioned between two lobes of the said second part, and vice versa, so that the lobes of the first part interdigitate with the lobes of the second part so that the said first part may be inserted into the said second part in an axial direction whereafter the said first part can be rotated relative to the said second part about the axis of the said through-hole to bring the lobes of the said first part into registration with the lobes of the said second part, so that the said first and second parts are no longer displaceable relative to one another in an axial direction.</claim-text> <claim-text>11. An artificial wrist component according to any one of claims 8 to 10, in which resilient plastics portions are provided on the lobes of one of the said first and second parts, preferably on the said first part, to eliminate the possibility of any raffle between the first and second parts.</claim-text> <claim-text>12. An artificial wrist component according to any one of claims 8 to 11, in which a bolt is inserted in respective cavities of the said first and second parts which are in alignment with one another when the lobes of the said first and second parts are in registration with one another, to inhibit relative rotation between the first and second parts about the axis of the said through-hole.</claim-text> <claim-text>13. An artificial wrist component according to any preceding claim, in which the said selectively adjustable tightener comprises a bolt which extends transversely of the axis of the said through-hole, through portions of the said first and second parts.</claim-text> <claim-text>14. An artificial wrist component according to claim 13, in which the bolt of the selectively adjustable tightener extends through a bolt which inhibits relative rotation between the said first and second parts.</claim-text> <claim-text>15. A method of making an artificial wrist component according to claim 10, comprising positioning each lobe of the first part between two lobes of the said second part, and visa versa, so that the lobes of the first part interdigitate with the lobes of the second part so that the said first part may be inserted into the said second part in an axial direction whereafter the said first part is rotated relative to the said second part about the axis of the said through-hole to bring the lobes of the said first part into registration with the lobes of the said second part, so that the said first and second parts are no longer displaceable relative to one another in an axial direction.</claim-text> <claim-text>16. An artificial wrist component substantially as described herein with reference to and as ifiustrated in the accompanying drawings. I. * * . * * * . *. .. 0 * * * **</claim-text>