US 3474466 A
Description (OCR text may contain errors)
Oc 28, 9 9 D. w. COLLINS GAS OPERATED ARM PROSTHESIS Filed June 9, 1967 United States Patent 66 Int. Cl. A61f 1/06, N04
US. Cl. 3-1.2 3 Claims ABSTRACT OF THE DISCLOSURE An apparatus for flexing an arm prosthesis at the elbow comprising a cylinder around which is a slidable sleeve. Within the cylinder is a gas storage flask which communicates, via valve means, with a space within the sleeve. The sleeve is connected to a forearm member in such a manner that, when gas under pressure from the flask is admitted to the space in the sleeve, the sleeve is moved slidably outwardly on the cylinder whereby the arm member is moved angularly about the elbow. The valve can be operated to shut off the gas pressure and opened to the atmosphere, thereby permitting the gas in the space to be exhausted, so that the forearm can return to its original position by virtue of its weight.
This invention relates to an arm prosthesis, and more particularly to a device for flexing an arm prosthesis at the elbow. The arm prosthesis may be an artificial arm, or an articulated splint (known as a flail splint) for supporting, and assisting movements of, a patient having an arm disability, for example a muscle or nerve disability causing partial paralysis.
It is an object of the invention to provide simple apparatus for providing powered, or power-assisted, flexion of an arm prosthesis at the elbow.
According to this invention apparatus for producing or assisting elbow flexion for an arm prosthesis comprises a cylinder, a sleeve slidably and sealably fitting around the cylinder, a gas storage flask within the cylinder, a pneumatic connection between the flask and a space within the sleeve, and means connecting the sleeve to an arm member, the arrangement being such that when gas pressure is applied to the said space, the sleeve is moved slidably outwardly on the cylinder whereby the arm memher is moved angularly about the elbow.
An example of the invention will now be described with reference to the accompanying drawings, in which:
FIGURE 1 is a partial side elevation of an articulated arm asisting splint or flail appliance, with parts of apparatus in accordance with the invention shown in section; and
FIGURE 2 is a partial end elevation looking in the direction of arrow A of FIGURE 1.
Referring to the drawings, a flail, appliance has an upper arm bar 15 and a forearm bar 16 pivotally connected at an elbow joint 17, so that the bar 16 can be moved angularly with respect to the bar 15. A flexed position of the bar 16 is indicated in dot and dash lines. Fixed to the upper end of the forearm bar 16 is a quadrant 13 having a peripheral groove in which lies a wire 8, the wire being anchored to the groove at point 8A. The wire runs over a pulley 10 to a second anchor point 9. The pulley is freely rotatable on axis 10A and is carried between the upper arm bar and a bracket 14.
It will be apparent that if point 9 is moved down, the wire will pull on the quadrant at point 8A, and cause the lower arm bar 16 to move angularly about the elbow.
A str-ap 1D is fixed as shown to the bar 15. This strap encircles and holds a thickened part 10 of a cylinder IB having a closed lower end 1A. This cylinder 1A, IB, 1C is thus immovably fixed to the bar 15.
The internal size of the cylinder is such as to receive snugly the body of a gas storage flask 18 the end 18A of which projects from the cylinder as shown, and includes a gas inlet and exhaust valve 18B.
A sleeve 4 fits slidably over the outside of the cylinder. It is shown in its normal, upper position, abutting the thickened cylinder part IC. Extending down over the upper end of the sleeve 4 is a protective sleeve 3 of plastics material.
The closed lower end 1A is grooved externally to seat two O-ring seals 5 which engage the inner surface of the slidable sleeve 4. The sleeve 4 has a closed lower end 6 with a bore 6A in which is fitted a gas inlet nipple 7. Thus when a connection (not shown, but of well-known type) between the valve 18B and the nipple 7 and the valve 18B is opened, gas flows through the nipple 7 into -a space 4A between the lower ends 1A and 6 respectively of the cylinder and sleeve 4, causing the sleeve to slide downwardly. The maximum stroke of the sleeve is indicated by the dot and dash line position shown, and in this position the top rim of the sleeve lies just above the lower rim of the protective sleeve 3.
Fixed to the lower end 6 of the sleeve 4 is a block 6B and fixed in turn to the block 6B is the anchor point 9 of the wire 8.
It will be seen that when pressure is admitted to the space 4A, the forearm bar 16 will be moved angularly. At the maximum outward stroke of the sleeve 4, the forearm bar 16 will be in the dotted line position shown.
When the valve 18B is operated to turn ofl the gas pressure and is opened to the atmosphere, gas from the space 4A will be exhausted thereby permitting the weight of the patients forearm, together with that of the bar 16, to turn the quadrant in reverse direction, so that the sleeve 4 is returned to its nonnal, upper position shown in full lines.
The quadrant, wire and pulley are housed between an inner metal plate 12 (FIGURE 2) and an outer cover 13 of plastic material.
What I claim is:
1. Apparatus for producing or assisting elbow flexion for an arm prosthesis comprising, a first and second arm member pivoted about an elbow joint, a cylinder, a sleeve slidably and sealably fitting around the cylinder, said sleeve defining a space with said cylinder at one end thereof, a gas storage flask within the cylinder, a pneumatic connection between the flask and said space within the sleeve, said connection including means for selectively admitting and exhausting gas to said'space, and means connecting the sleeve to one of said arm members and the cylinder to the other of said arm members, the arrangement being such that when gas pressure is applied to the said space, the sleeve is moved slidably outwardly on the cylinder whereby said one arm member is moved angularly about the elbow joint.
2. Apparatus for producing or assisting elbow flexion for an arm prosthesis comprising, an upper arm member and a forearm member connected for angular movement therewith, a cylinder fixed to said upper arm member, a sleeve slidably and sealably fitting around the cylinder, said sleeve defining a space with said cylinder at one end thereof, a gas storage flask within the cylinder, a pneumatic connection between the flask and said space within the sleeve, the connection including valve means whereby gas can be admitted to the space and exhausted therefrom, a quadrant fixed to the upper end of the forearm member, and a flexible pull element anchored at one 3 4 end to the quadrant and secured at its other end to the 2,512,526 6/1950 Hauser 312.2 sleeve, the arrangement being such that when gas pres- 2,832,334 4/1958 Whitelaw 128-25 sure is applied to the said space, via the said valve means, 3,007,176 11/ 1961 Hafner 3-1.2 the sleeve is moved slidably outwardly on the cylinder and exerts a pull on the element whereby the forearm 5 FOREIGN PATENTS member is moved angularly with respect to the upper 828,291 1/1952 Germany.
arm member; the gas on being exhausted from the space 117,204 Great Britain. permitting the sleeve to return to its original position.
3. Apparatus according to claim 2, wherein the upper RICHARD GAUDET, Primary Examine! arm member mounts apulley over which the pull element 10 L FRINKS Assistant Examiner passes.
References Cited US. Cl. X.R.
UNITED STATES PATENTS 3-12.3; 91-216; 128-25 2,259,911 10/1941 Tancred et al. 3-1.2 15