Shoulder disarticulation prosthetic system

• US 3,866,246 A
• Filed: 11/14/1972
• Issued: 02/18/1975
• Est. Priority Date: 11/14/1972
• Status: Expired due to Term

• Current Assignee: Gerhard Schmeisser, Woodrow Seamone
• Original Assignee: Gerhard Schmeisser, Woodrow Seamone
• Inventors: Schmeisser, Gerhard, Seamone, Woodrow
• Primary Examiner(s): Frinks, Ronald L.
• Application Number:
  US05/306,480
• Time in Patent Office: 826 Days
• Field of Search: 3/1-1.2,12-12.7
• US Class Current: 623/24
• CPC Class Codes: A61F 2/58 Elbows; Wrists ; Other joints; Hands
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2002/30523 by means of meshing gear teeth
• CPC Class Codes: A61F 2002/701 operated by electrically controlled means, e.g. solenoids or torque motors
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements

Abstract

The invention is an externally powered prosthesis for shoulder disarticulation amputees. Proportional control of the prosthesis is provided by a displacement sensor preferably comprised of a movable magnet and a stationary semiconductor element which responds to changes in magnetic field strength. The movable magnet is displaced by the transverse motion of the amputee'"'"''"'"'s skin (caused by controlled flexure of a suitably located muscle), thereby producing a signal in the semiconductor element which is proportional to the skin motion. Control of the prosthesis is then accomplished by amplification and utilization of the signal to drive an electric motor powered by an external battery.

Claims

1. A control system for actuating a prosthesis from voluntary skin movement of a user, comprising:

a prosthesis;

displacement sensing means for measuring the amplitude of movement of a point on the skin of a user of the prosthesis, the sensing means comprising a magnet, connecting means joined to the magnet and adapted to be connected to a point on such user'"'"''"'"'s skin, and magnetic field sensitive means for sensing a change in the magnetic field on displacement of the magnet by motion of that point on such user'"'"''"'"'s skin to which the connecting means is joined;

means for actuating said prosthesis in response to said sensed skin movement; and

means for providing a position feedback signal to said actuating means for identifying the degree of actuation imparted to said prosthesis.

2. The control system of claim 1, and further comprising means for delaying in time said position feedback signal.

3. A control system for actuating a prosthesis from voluntary skin movement of a user, comprising:

a prosthesis;

means for sensing displacement of a point on the skin of a user of the prosthesis, said means comprising, a magnet, connecting means joined to the magnet and adapted to be connected to a point on such user'"'"''"'"'s skin, and magnetic field sensitive means for sensing a change in the magnetic field occurring on displacement of the magnet relative to said magnetic field sensitive means, the displacement of the magnet occurring due to voluntary motion of that point on such user'"'"''"'"'s skin to which the connecting means is joined;

means for converting the sensed skin displacement into a DC level signal having an amplitude proportional to the magnitude of the skin displacement;

means for identifying the exact physical Position of said prosthetic device and for producing therefrom a position feedback signal;

means for actuating said prosthesis in response to said sensed skin displacement, said actuation means providing an electrical signal sufficient to actuate said prosthesis and including a summing amplifier for producing said electrical actuation signal when the resultant threshold output amplitude of said means for converting the sensed skin displacement into a DC level signal is greater than the amplitude of said position feedback signal;

means for converting said electrical signal into mechanical energy; and

, means for producing a control signal effective to actuate said prosthetic device only when the sensed skin displacement is above a predetermined threshold level, said degree of prosthetic actuation being proportional to the amplitude of said sensed skin displacement, said means for producing said control signal comprising a standard waveform generator producing a predetermined amplitude signal, said electrical actuation signal being generated when said output amplitude of said summing amplifier is greater than said predetermined amplitude of the standard waveform signal.

4. The control system of claim 3 wherein the magnetic field sensitive means is a semiconductor.

5. The control system of claim 3 wherein said means for producing a position feedback signal comprises a potentiometer whose wiper arm is mechanically actuated in direct proportion to the degree of actuation imparted to said prosthesis, the voltage sensed by said wiper arm being received by said actuating means.

6. The control system of claim 3 and further comprising means for delaying in time said position feedback signal.

7. The control system of claim 3 wherein said means for converting said electrical signal into mechanical energy comprises a DC motor.