Continuous passive motion devices and methods

• US 4,875,469 A
• Filed: 06/13/1988
• Issued: 10/24/1989
• Est. Priority Date: 06/13/1988
• Status: Expired due to Fees

• Current Assignee: Lenjoy Engineering
• Original Assignee: Innovative Medical Engineering, Inc.
• Inventors: Carian, Peter J., Moore, James D., Rotter, Leah D., Landsinger, Edmund E., Schreiber, Stanley, Brook, Arthur H., Katzin, Leonard
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): Cheng, Joe H.
• Application Number:
  US07/206,269
• Time in Patent Office: 498 Days
• Field of Search: 128/26, 623/25, 623/64, 272/67
• US Class Current: 601/40
• CPC Class Codes: A61H 1/0288 Fingers

Abstract

A system for continuous passive motion of a limb or one or more fingers comprises a reciprocable carriage coupled to a drive belt which is driven by a motor through a disengageable clutch. A second drive belt also driven by the motor, and the first drive belt, carry elements whose positions can be sensed to control limits of motion. Individual finger actuators, adjustable in length and with internal springs, couple engagement means on the fingers to the carriage, which can be driven so as to provide predetermined dwell times at limits of flexion and extension.

Claims

1. The method of operating a continuous passive motion device for the fingers, to provide a controlled range of motion for each finger, using a reciprocable carriage to which individual finger attachable and length adjustable finger actuators are secured and also using a pair of movable belts, comprising the steps of:

moving the carriage with a first belt to an anterior limit of position while maintaining a second belt at a posterior limit of position;

securing the individual finger actuators to the tips of the fingers while adjusting the length of the individual finger actuators;

flexing the fingers, the carriage, and the individual finger actuators while maintaining the second belt at the posterior limit position,

coupling the two belts together; and

driving the two belts together in reciprocating fashion by sensing an anterior limit position of the first belt and the posterior limit position of the second belt.

2. The method as set forth in claim 1 above, including the additional step of having a dwell time at the anterior limit of motion while concurrently tensioning the fingers individually.

3. The method set forth in claim 2 above, further including the steps of indexing the second drive belt to the posterior limit position before moving the carriage, and adjusting the lengths of the finger actuators to provide tension at the posterior limit position.

4. A method of exercising a finger with a continuous passive motion device comprising the steps of:

moving the finger in a first direction against a first spring force, movement in the first direction tending to orient the finger in an extended position;

moving the finger in a second direction opposite the first direction against a second spring force, movement in the second direction tending to orient the finger in a contracted position;

maintaining the finger in the extended position against the first spring force for a dwell time between motion reversals; and

securing the finger to a individual finger attachable and length adjustable finger actuators and to a reciprocable carriage such that a tensile force is exerted on the finger at a limit of motion for both extension and flexion.

5. A system for providing continuous passive motion of at least one of the fingers of the hand comprising:

a support for securing the system to the region of the wrist;

a housing rigidly coupled to the support for containing a drive mechanism, the housing including rigidly mounted motor means, battery means for energizing the motor means, and controller means for varying the excitation of the motor means in speed and direction;

a pair of belt drives coupled to the housing, and movable with respect thereto, a first of the belt drives being coupled to the motor means by clutch means and a second of the belt drives being directly coupled to the motor means;

carriage means being slidably mounted on the housing and coupled to the first belt drive, the first and second belt drives and the carriage means being movable along a predetermined axis generally parallel to the direction of desired finger movement;

adjustable elongated means pivotably coupled to the carriage means and extending therefrom in the direction of the finger tips parallel to the predetermined axis, and each of the adjustable elongated means including means for gripping a finger, such that motion of the motor means may be coupled to the adjustable elongated means so as to manipulate each gripped finger;

sensors means for sensing an anterior limit position of the second belt drive;

and wherein the controller means includes means for driving the motor means in reversing directions such that the belt drives move together between the anterior and posterior limit positions sensed by the sensor means when the clutch means is engaged so as to define a region of manipulation for each gripped finger.

6. A system as set forth in claim 5 above, including lever means cooperatively connected to the clutch means for engaging the clutch means to drive the belt drives together so as to ultimately control the manipulation of each gripped finger.

7. A system as set forth in claim 5 above, wherein said means for gripping a finger comprise individual lengthwise adjustable elements having extensible spring means coupling said adjustable elongated means to the individual fingers so as to compensate for varying lengths of finger.

8. A system as set forth in claim 11 above, further comprising:

(a) the pair of belt drives is spaced apart and parallel belt drives, each of the belt drives having first and second ends and including pulley means proximate the first and second ends of the belt drives;

(b) flag means mounted in a selected region of the belt drives;

(c) a first photoelectric flag sensor means positioned at the posterior limit position; and

(d) a second photoelectric flag sensor means positioned at the anterior limit position.

9. A system as set forth in claim 8 above, wherein the clutch means comprises a member axially movable along a predetermined motor shaft axis, to engage a concentric pulley of the pulley means for the second belt drive to the motor shaft axis, and lever means for controlling the clutch means position;

and wherein the system further includes a cover to engage the lever means for engaging the clutch means into an automatically run position when the cover is closed.

10. A system as set forth in claim 5 above, wherein the adjustable elongated means comprise a base tube, an elongated rod adjustably seated in the base tube, first and second springs having predetermined compliance disposed serially within the base tube, and an elongated wire extending through the elongated rod and disposed between the first and second springs and coupled at a first end to the means for gripping the finger, such that the springs permit relative movement against resistance.

11. A system as set forth in claim 5 above, wherein the means for gripping the finger includes a separate finger holder for attachment to the tip of each finger to be subjected to motion, the separate finger holder including an extending lever arm for attachment to the elongated wire, and means for resiliently securing the separate finger holder to the finger.

12. A system as set forth in claim 11 above, wherein the finger holder has a substantially semicircular shape in cross section, including a base portion coupled to the lever, and side panels, the side panels being coupled to the base portion by hinges.

13. A system as set forth in claim 12 above, including a foam insert within the semicircular structure having adhesive on both sides, the side panels engaging the side of the finger and controlling motion of the finger substantially by shear forces.

14. A system as set forth in claim 5 above, wherein the support includes side surfaces along the direction of movement of the carriage means for limiting a degree of divergence of the adjustable elongated means.

15. A system as set forth in claim 14 above, including pivot pins coupling the adjustable elongated means to the carriage means to permit the degree of divergence between the adjustable elongated means.

16. A system as set forth in claim 11 above, wherein the system operates in a cyclic fashion, and includes means for counting and displaying the cycles undertaken, and means for starting running of the carriage means between the anterior and posterior limit positions when a cover mounted on the housing is closed.

17. A system as set forth in claim 5 above, wherein the adjustable elongated means includes spring means for exerting tension on the fingers when the fingers are in an extended position, and the controller means prevents movement of the carriage means for a predetermined dwell time when the fingers are in the extended position, so as to maintain the fingers under tension for a period of time before the controller means permits movement of the carriage means.

18. An actuator for coupling a reciprocating member in a continuous passive motion device to a finger to be exercised along a selected direction, comprising:

length variable actuator rod means for engagement to the device and movable therewith along the selected direction;

substantially linear flexible actuator wire means disposed partially inside the actuator rod means along the selected direction for coupling at an opposite end to the finger to be exercised; and

a pair of spring means coupling the rod means to the wire means to provide spring force on the finger in each direction without regard to dimensions of the finger when the actuator rod means has been adjusted.

19. An actuator as set forth in claim 18 above, wherein the actuator rod means comprises a base sleeve and an extension rod telescoped into the sleeve, and wherein the wire means extends the extension rod, and the spring means are disposed within the extension rod on opposite sides of an end of the wire means and exert force on the finger via the wire means depending on the direction of movement of the actuator rod.

20. A drive system for reciprocating a carriage in a continuous passive motion device comprising:

a battery;

a drive motor including a drive shaft;

controller means for energizing the motor at selectable speeds and directions;

belt drive means comprising first and second parallel belt drives disposed along a predetermined path, and including pulleys adjacent each end of the first and second parallel belt drives along the path, wherein the pulleys at one end of the first and second parallel belt drives are concentric with the drive shaft;

a first one of said pulleys is coupled to the drive shaft, and the first parallel belt drive is engagable to an adjacent carriage and a second one of said pulleys;

clutch means for selectively coupling the second one of the pulleys to the drive shaft;

separate flag means coupled to each of the belt drive means and movable therewith; and

separate sensor means disposed along the predetermined path at selected regions, the sensor means being coupled to the controller means to generate control signals.

21. A drive system as set forth in claim 20 above, wherein the separate flag means comprise a first flag individually coupled to the first belt drive means and a second flag individually coupled to the second belt drive means wherein the separate sensor means for the first flag on the first parallel belt drive is disposed in a reciprocal travel limit position and the separate sensor means for the second flag on the second parallel belt drive is disposed at an opposite travel limit position.

22. The drive system as set forth in claim 21 above, wherein the clutch means comprises a clutch member reciprocable on the motor drive shaft between the pulleys, wherein the second pulley is slidable along the drive shaft of the drive motor, and wherein the system further includes control handle means for controlling the position of the first pulley on the motor shaft and spring means for urging the second pulley toward the clutch means and the first pulley.

23. An actuator for coupling a reciprocating member in a continuous passive motion device to a limb to be exercised along a selected direction, comprising:

length variable actuator rod means for engagement to the device and movable therewith along the selected direction;

substantially linear flexible actuator wire means disposed partially inside the actuator rod means along the selected direction for coupling at an opposite end to the limb to be exercised; and

a pair of spring means coupling the rod means to the wire means to provide spring force on the limb in each direction without regard to dimensions of the limb when the actuator rod means has been adjusted.