US2528464A - Hydraulic artificial arm - Google Patents

Description

Oct. 31, 1950 v. o. WILKERSON ETAL 2,528,464

' HYDRAULIC ARTIFICIAL ARM Filed April 4, 1947 4 Sheets-Sheet 1 INVENTOR wcroa o. wmwzsou JOSEPH A. MAZZOLA v BY -Oct. 31, 1950 v. o. WILKERSON EIAL 2,528,464

HYDRAULIC ARTIFICIAL ARM 4 Sheets-Sheet 2 Filed April 4, 1947 INVENTOR VICTOR. O. WlLK-EBfiON JOSEPH A. MAZZOLA Oct. 31, 1950 v. o. WILKERSON EI'AL HYDRAULIC ARTIFICIAL ARM 4 Sheets-Sheet 3 Filed April 4, 1947 ENVENTOR VECTOQ 0. WWILEQSON g E A. 4

Oct. 31, 1950 v. o. WILKERSON ErAL HYDRAULIC ARTIFICIAL ARM 4 sheets sheet 4 I Filed April 4, 1947 lNVENTOR VNZTOQ. O. WILKEQSON JOSEPH A. MAZZOLA Patented Oct. 31, 1950 HYDRAULIC ARTIFICIAL ABM Victor 0. Wilkerson, Vestal, and Joseph A. Manzola, Endicott, N. Y., assignors to International Business Machines Corporation, New York, N. Y., a corporation oi New York Application April 4, 1947, Serial N 0. 739,318 11 Claims. (Cl. 3-12) This invention relates to an artificial hand and arm and its general object is to provide a device of this kind which will imitate closely the principal movements of a natural hand and arm.

A particular object of the invention is to provide a device of the kind described including a gripping means actuated by a foot motion.

A further object is to provide an artificial hand and arm including means for pronation and supination of the hand.

A still further object is to provide an artificial hand and arm havin a plurality of difierent kinds of motions, the power therefore being supplied by foot motion, and the kind of motion being selected by shoulder shrugging.

Another object is to provide an artificial hand and actuating means therefore including locking means to maintain the hand in gripping position without further muscular exertion.

A still further object is to provide a hydraulically operated artificial hand and arm including safety means to prevent excessive pressure in the system.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applyin that principle.

In the drawings:

Fig. 1 is a full length front view of an amputee, illustrating the method of attachment of the artificial hand and arm and its operating means. I

Fig. 2 is a partial rear view of the same.

Fig. 3 is a perspective view of a clip for securing a part of the apparatus to the belt of the amputee.

Fig. 4 is a side elevation of the foot operated pumpand harness therefore.

Fig. 5 is a longitudinal section of the pump.

Fig. 6 is a vertical section through the valve mechanism.

Fig. 7 is a longitudinal section of the hand.

Fig. 8 is a cross section on the line 8-8 of section 7.

Fig. 9 is a sectional view of a portion of a mechanism shown in Fig. 7, taken in a plane behind that of Fig. 7. It shows the mechanical locking means of the gripping mechanism.

Fig. 10 is a detail view of the mechanical looking means shown in Fig. 9, looking at the-same from the side opposite of that of Fig. 9.

Fig. 11 is a side elevation, with parts in section, of a modified, bulb-operated form of releasing means for the hydraulic locking means.

Fig. 12 is a perspective view of an artificial arm showing the method of associating the bulb therewith.

The illustrative embodiments of the invention are hydraulically operated devices designed for an amputee still having a part of his forearm. A hand 10 is rotatively mounted upon a supporting sleeve I l adapted to slip over the forearm stump. The sleeve II is connected by hinged straps l2, providing an elbow joint, to a band It adapted to be buckled around the upper arm. The band It is connected by straps l4 to a shoulder harness II The system includes a foot operated pump 20 connected to the hand mechanisms by conduit means including a tube II, a valve unit 22, and two tubes 23 and 24. The valve mechanism has an arm 25 for operating the valve which places the tube 2| in communication with either of the tubes 23 or 24. A second arm 26 controls a check valve which hydraulically locks the hand actuating mechanism, in a manner to be described later. The arm 25 is connected by a cord 21 passing through a loop 28 to a tab 29 on the right shoulder portion of the harness l5. The arm 26 is connected by a cord 30 to a tab 3| on the left sleeve of the shoulder harness. presently that the system provides for grasping movements and wrist turning movements, which can be executed successively in such a way that an object can be grasped and then the hand can be turned at the wrist while the grasp is retamed. v

The details of the construction of the hand are shown in Figs. 7 to 10. A hollow palm member 40 has two grasping elements jointed to it, namely, a finger element 4| and a thumb element 42. The finger element is jointed to the palm member by a pivotal connection 43 and the thumb member by a pivotal connection 44. Any suitable material may be used for these parts, but a fiesh colored plastic material which can be molded to the proper shape is preferable. The finger element can be replica of the four fingers, molded in one block.

The thumb has rigid therewith a lever arm 45 to which is connected 9. spring 46 anchored at 41, which normally holds the thumb in open position. The end of the lever arm 45 is pivotally connected at 48 to a piston 49 operating in a cylinder 50. The head of the cylinder is rotatably mounted by a pivot pin II upon a bracket 52 secured to the inside of the palm member 40. The tube 23 is connected to a nipple 53 communicating with the space within the cylinder 50. When the pressure fluid is forced into the cylinder the It will be seen thumb will rock on its pivot 44 toward the finger element 4|, tensioning the spring 40. When the pressure fluid is released the spring will return the thumb to the position shown in Fig. '1.

The flnger block 4| has rigid with it a lever arm (see Fig. 9) at the end of which a dog 6| is pivoted upon a pin 02.

A spring 63 coiled upon the pivot 43 of the finger block is anchored at one end upon a stationary pin 84 on the bracket 52, while its other end pointed end of the dog 6|, in a manner to be described.

The spring 63 tends to rock the dog 6| clockwise about its pivot 62, but the spring 46 is I stronger than the spring 63 and the cam lever 01, upon "which the cam follower 68 rides, normally holds the dog 8| in the counterclockwise limit of its rocking movement in relation to the lever arm 60 and, furthermore, rocks the finger block 4| to its normal open position. When the thumb 42 is rocked. by hydraulic pressure fluid, toward the finger block, to grasp an object, the cam lever 61 rocks toward the wrist and allows the cam follower 66 to move outwardly along it, thereby permitting the finger block to be rocked by the spring 6-3 toward the thumb. When the finger block strikes the object and its rocking is stopped, further movement of the thumb allows the dog 6| to turn on its pivot 62, under the influence of spring 63, and engage the teeth of the anchoring device 69. This looks the finger block against movement away from the thumb. In efiect, the finger block becomes rigid with the palm member, against the grasping force of the thumb. When the hydraulic pressure is released and spring 46 moves the thumb outward, the cam lever 61 first rocks dog 6| out of engagement with anchoring member 69, then, when lug 68 strikes lever arm 60, rocks the finger element toward open position.

- A particular object of the invention is to provide pronation and supination movementof the hand. The construction shown in Figs. 7 and 8 accomplishes this result. A barrel 0|, is clamped to the base portion 80 of the palm member by a nut 82. The barrel extends through a wrist section 03 of the supporting sleeve II, being mounted therein by ball bearings 84 and 85 seated in a bearing housing 86 secured by screws 81 to a transverse partition 88 of the sleeve II. The lower part of the bearing housing contains a bushing 90 in which travels a cylinder III. with in the cylinder is a piston 92 rigidly mounted on the bearing housing and having a bore 93 through it. Pressure fluid is supplied through tube 24 to the end space 94 of the cylinder 0|. The upper side of the cylinder is provided with rack teeth 95, which are exposed through an opening in the bushing 90, to mesh with a sector of teeth 96 on the mid-section 91 of the barrel 0|. A spring 98 surrounding a cylindrical portion of the bearing housing has one end 93 anchored in a hole in the bearing housing and the other end I00 extending into a hole in the base portion 80- of the palm member 40. In the normal condition of the spring the hand is in the prone position shown in Figs. 1 and 2. When pressure fluid is forced into the cylinder SI and moves the latter to the left in Fig. 8, the hand rotates to a supine position, its movement being limited by a screw IOI extending through the bearing housing into the gap between the ends of the sector-of teeth 96. The tube 23 extends through the hollow of the barrel member 8|, into the hollow space of the sleeve II. The tubes 23 and 24 turn out through holes I02 in sleeve II and run along the outside of the sleeve, curving under the arm pit to connect with nip-pies I05 and I00 (Fig. 6) on the valve unit 22.

Turning now to Figs. 4 and 5, the foot operated pump comprises a cylinder H0 in which travels a piston III. The piston has rigidly secured thereto a sleeve II2 slidably receiving a rod II3, the lower end of which rod has a ball I and socket connection II4 to a fastener II5 secured to a heel plate H6. The heel plate III; is connected by a strap II1 to an ankle plate II8 attached to the leg by straps H9 and I20. The cylinder H0 is pivotally supported at its upper end by a bracket I2I on the plate IIO. Within the tube 2 is a short rod I22 fixed to the piston III. The rod I22 normally rests upon the end of the rod H3, and holds the piston III in the dotted line position I I la in Fig. 5, when the foot is in the normal position. The piston can move down to the full line position, when the foot is cooked up to the angle shown in Fig. 4, or it can be moved up to the dot and dash line position II lb, by pointing the toe downward. The operation of the pump will be described a little later.

The tube 2| is connected to a nipple I (Fig. 6) on the valve unit 22, which leads into a chamber I3I. At the exit from the chamber I3I into a chamber I32 is a valve seat upon which a check valve I33 is pressed by a spring I34. The spring I34 is held down by a screw cap I35. The chamber I32 is in communication with a cross channel I35 at the center of which is located a valve bushing I31. A valve I38 in said bushing'has ducts I39 and I40 providing selective communication between a port I in the valve bushing, which lies within the cross channel I36, and any one of three ports I42, I43 and I44. The port I42 opens into a filling hole I closed by a screw I46. The port I43 communicates with nipple I06, to which is attached the tube 23. The port I44 opens into a chamber communicating with the nipple I05, to which is attached the tube 24. When the pressure fluid is forced by the pump 20 through the tube 2| and past the check valve I33, it is directed by the valve I38 either through the tube 23 to the cylinder in the palm of the hand,

which actuates the grasping elements, or it is directed through the tube 24 to the cylinder 9| in the wrist, which rotates the hand to the supine position. The angular position of the valve I38 is controlled by the arm 25, which is tilt-ed upward to the position shown in Fig. 11, by shrugging the right shoulder and thereby pulling the cord 21. The valve I38 is restored by a spring I41 to a normal position in which the fluid is forced through the tube 23 to execute the grasplng action. When the right shoulder is shrugged and the foot pump is operated, the fluid is forced through the tube 24 to rotate the hand. Fig. 6 shows the valve in the filling position, to which it can be turned by rocking the arm 25 down from a horizontal position.

When the pressure fluid is forced into either of the cylinders 50 or III, the check valve I33 locks the fluid in them. Means are provided to release the check valve, to permit the pressure fluid to return out of the cylinders 50 or 9|. For

' this purpose a plunger I33 is slidably mounted in the valve casing, in position to be pressed against'the valve I33, to raise it from its seat. The plunger I33 is normally held down by a spring I6I inserted between the head I32 of the plunger and the top of the chamber I63 containing the spring. A lever rockably mounted by its shaft I64 in the valve casin has an arm I66 bearing against the plunger head I62. The arm '26 is flxed to the shaft I63 and can be rocked by shrugging the left shoulder and pulling the cord 33, to press the plimger I60 up and release the check valve I33. The head of the plunger is sealed against the wall of the chamber I63 by a ring I63.

An alternative means for releasing the check valve is the hydraulic device shown on Figs. 11 and 12. A plunger I63 having a head I62, spring -I6I, and ring I66, is provided, as before. In this case the chamber I63 is capped by a nipple I61 connected by a tube I63 to a bulb I63. As shown in Fig. 12. the bulb can be located within the sleeve II. for example, in position to be squeezed by the forearm stump I13. The bulb I63 and tube I63 are filled with fluid which presses up the plunger I63 to release the check valve.

Means are provided to prevent excessive pressure of the fluid on the tubes. Relief valve I63 is pressed by a spring "I against a valve seat I62, the aperture of which communicates with the cross channels I36. The spring I 6| is compressed by a screw cap I63. The fluid passing through the valve I62 escapes through a duct I64 into a cylinder I66 containing a piston I66 held up by a spring I61, the piston bein displaced accordingly. When the pressure in the system is released by operation of the check valve I33, the spring operated piston I66 forces the liquid past an overflow valve I63 back into the cross channel I36. I

The valve unit is provided with a clip I16 of the form shown particularly in Fig. 3. The upward fold I16 of the clip can be fitted over the belt. while the downward fold I11 provides space for [the shirt to be tucked in, the valve unit being hidden inside the shirt.

The operation of the apparatus is as follows:

Assume that the amputee is standing with his foot flat on the ground and that he wishes to grasp an object. The piston of the foot pump at this time is in the position Ia and the valve I36 is in the position with the arm 26 horizontal and the port I33 providing communication between thechannel I36 and the tube 23. The check valve I33 is released by shrugging the left shoulder and the foot is cocked to the position shown in Fig. 4. This draws the rod I I2 down and allows the piston III- to descend to the full line position of Fig. 5, the top of the cylinder I I3 being filled with fluid entering through the pipe 2I from the upper part of the system.

The left shoulder is now dropped to-the normal position, allowing the check valve I33 to close and the foot is moved down toward the horizontal position. This forces fluid from the cylinder lIIi through the valve unit and tube 23 to the cylinder 63 in the palm of the hand. The thumb and finger elements rock toward each other and by continued movement of the foot after first contact is made with the object, the grasping pressure can be made as strong as desired, up to the limit allowed by the overflow device in the valve unit. If the foot is moved still further, overflow liquid passes into the cylinder I66, depressing the piston I66 against the force 8 of spring I61. The check valve I33 locks the pressure fluid in the cylinder III and maintains the grasp without further eflort by the foot.

If itis now desired to move the hand to the supine position, the right shoulder is shrugged and the valve I33 is rocked to the position in which channel I33 connects cross channel I36 with the port I. which communicates with the tube 24. Rotation oi the hand at the wrist will now occur in response to the fluid flowing out of the reservoir cylinder I66 through the valve and tube 23, into the cylinder 3|. Further rocking of the foot may be required to supply enough pressure fluid to complete the desired movement of the hand. The check valve again locks the pressure fluid in the cylinder 3| and maintains the hand in the supine position, against the force of the spring 33. r If the amputee now wishes to walk, he points his toe downward, forcing the piston III up to the position IIIb in Fig: 5, the excess fluid passing into the overflow cylinder I66 and being locked therein by the check valve I33. The foot is now free to execute all the movement required in walking, the rod II3 simply sliding in and out of the tube II2, while the piston III remains at the upper end of the cylinder I III.

The hand can be restored to the prone position by shrugging both shoulders at once, thereby connecting the tube 23 through the valve unit with the tube 2I and releasing the check valve I33 at the same time. The grasp can be released by shrugging the left shoulder alone, whereby the check valve I33 is opened while the tube 23 is placed in communication with the tube 21 through the valve unit. As the pressure fluid flows out of the hand operating cylinders into the pump cylinder I III, the piston I I I moves down as far as permitted by the position of the rod I I3 at the time.

The movements of the hand are derived from limited movements of the foot. It is desirable to reduce as far as possible the demands of the grasping movements of the thumb and flnger elements on the pressure fluid supplied from the pump. This is accomplished, in accordance with the present invention, by the construction of the grasping mechanism, which utilizes the force of a spring to move the finger block up to the point where it makes contact with the object to be rasped, the pressure fluid being used only to move the thumb. If the hydraulic mechanism in the palm were required to operate the finger element directly, in addition to the thumb, it would consume a considerable amount of the limited fluid supply, to perform this work, which, in accordance with the invention, is performed by the spring 63.

The construction just referred to also eliminates the need for a driving ratio change device to be operated by the other hand.

- It will be observed that the system enables the wearer to perform such an operation as to grasp asuitcase handle, lift it, and walk with it, because of the check valve which maintains the grasping pressure, while the foot is freed from the pump by the sliding connection between the rod H3 and the piston assembly III, II2. It is also possible, with this device, to grasp an object and then to turn the hand from a prone to a supine position while the grasp is maintained by the locking of the pressure fluid in the tube 23 by the valve I33. Moreover, the maintenance of grasping pressure is not dependent upon continued muscular exertion, but is taken care of by the check valve or the control valve.

' While there have been shown and described and pointed out the fundamental novel features of the invention as applied to two preferred embodiments, it will be understood that, various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

Whatis claimed is:

1. In an artificial hand, a palm member, two grasping elements Jointed thereto, expansible hydraulic means anchored at one end to said palm member and at its other end to one of said grasping elements, for rocking the latter, impositive means for rocking the second of said grasping elements toward said first grasping element, and means for locking said second grasping element to said palm member.

2. An artificial hand as described in claim 1, wherein means are provided to control the movement of said second grasping element in accordance with the position of said first grasping element.

3. An artificial hand as described in claim 1, wherein means are provided to control the movement of said second grasping element in accordance with the position of said first grasping element, said last means including means to render actuating means including a valve for directing.

pressure fluid selectively to said hydraulic actuating means, and manipulative means for controlling saidvalve.

5. An artificial hand system as described in claim 4, wherein said manipulative means comprises a shoulder harness and means connecting the latter to said valve.

6. An artificial hand systemas described in claim 5, wherein the hydraulic actuating means for said hand members includes spring return means, said conduit means including a check valve for locking the pressure fluid against the action of said spring return means, and manipulative means for releasing saidchecl: valve.

7. In an artificial hand and'arm, a supporting sleeve, 9. hand including grasping means, means rotatively mounting said hand upon said sleeve to. provide pronation and supination of said hand, separate hydraulic actuating means for rotating said hand and for operating said grasping means respectively, a loot-actuated pump, a conduit means for conducting a fluid from said pump to said hydraulic actuating means, said conduit means including a valve for directing the pressure fluid to either of said hydraulic actuating means, and manipulative means for controlling said valve.

8. An artificial hand as described in claim 7, wherein said pump includes a cylinder, a piston therein, and an actuating rod having only a pushing contact with said piston.

9. An artificial hand as described in claim 8, wherein the manipulative means for releasing said check valve comprises a hydraulically operated releasing device, and a tube and bulb containing a fluid connected to said hydraulic releasing device, whereby said bulb can be positioned for application of pressure thereto to exert a hydraulic pressure on said hydraulically operated releasing means.

10. In an artificial hand and arm, a supporting sleeve, 9. hand including grasping means rotatively mounted on said sleeve to provide pronation and supination movement of said hand, hydraulic actuating means for rotating the hand in one direction, yieldable means for rotating said hand in the opposite direction, fluid pumping means, and conduit means connecting said pumping means with said hydraulic actuating means, including a check valve to ,lock the fluid in said hydraulic actuating means against the force of said yieldable means.

11. In an artificial hand system, a mechanical hand including grasping means, hydraulic actuating means for the said grasping means, pumping means consisting of a cylinder and a piston freely movable therein, a foot-operated element for moving said piston to force pressure fluid into said hydraulic actuating means, and conduit means interconnecting the said actuating, means with the said pumping means including a check valve for maintaining pressure therebetween, the said conduit means including astorage device having a spring-operated iston and cylinder into which fluid can be forced on passing said valve by travel 01' the loot-operated element to an extreme'position whereby the pressure fluid is locked by the said check-valve.

VICTOR O. WILKERSON. JOSEPH A. MAZZOLA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Arana, Bosch Las Amputaciones Cineplastics, Buenos Aires, Argentina 1920, page 304, Figure 170.

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