Apparatus to exert traction in traction therapy

• US 4,365,623 A
• Filed: 03/06/1980
• Issued: 12/28/1982
• Est. Priority Date: 03/06/1980
• Status: Expired due to Term

• Current Assignee: 501 Tru-Trac Therapy Products Incorporated
• Original Assignee: Tru-Eze Manufacturing Company Incorporated
• Inventors: Wilhelm, Tru G., Wilhelm, Bradley T., Ross, Heinz C.
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): Wallen, T. J.
• Application Number:
  US06/127,874
• Time in Patent Office: 1,027 Days
• Field of Search: 128/75, 128/84 R, 128/84 B, 128/84 C, 340/668, 254/272, 254/355
• US Class Current: 602/32
• CPC Class Codes: A61H 1/0218 Drawing-out devices suspension devices for supporting the patient in upright walking or standing position A61H3/008; orthopedic devices for non-surgical treatment A61F5/01; stretching fractured limbs A61F5/04

Abstract

Therapeutic traction apparatus for exerting sequential changes in tension pull on a flexible line which is attachable to a traction harness. The apparatus is responsive to tension which exists in the line. A timer can be provided to establish pause and dwell times, and a programmed control can be provided to establish various tension levels and types of sequences.

Claims

1. Apparatus for exerting traction force in traction therapy, said apparatus comprising;

a flexible line by means of which said force is to be exerted;

drive means to which said line is engaged for pulling in and paying out said line;

a motor operatively engaged to said drive means;

motor control means operatively interposed between said motor and a source of energy for driving said motor, said motor control means having a first and a second control condition for respectively causing said motor to pull in or to pay out said line, and a third control condition where it does neither;

tension sensing means responsive to tension exerted on said line and adapted to provide a signal which is proportional to the value of said tension;

program means comprising circuitry defining a predetermined sequence of motor operations to establish a predetermined sequence of tension values on said line, said program means being operationally coupled to said tension sensing means and to said motor control means to cause said motor control means sequentially to assume appropriate ones of its control conditions so as to attain said predetermined sequence of tension values in said line;

and

transmission means including a clutch interposed between said motor and said drive means, and a cam and a cam follower interposed between said clutch and said tension sensing means, said cam and cam follower being so constructed and arranged as to hold said clutch engaged when there is tension in said flexible line above some minimum value.

2. Apparatus according to claim 1 in which said cam is moved by said tension sensing means, and in which said follower is moved by solenoid means actuable to engage said clutch, said follower being movable by said solenoid to clear said cam, whereafter, de-energizing said solenoid while tension is on said line, causes interference of said follower and cam and prevents dis-engagement of said clutch.

3. Apparatus according to claim 2 in which said clutch comprises a movable support plate, and an intermediate gear rotatably mounted to said support plate, adapted to interlink said motor and said drive means when said solenoid is energized.

4. Apparatus according to claim 3 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence, sequence means for referring sequentially to said value in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

5. Apparatus according to claim 2 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence sequence means for referring sequentially to said values in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

6. Apparatus according to claim 1 in which said follower includes second cam means, and in which a motor-enabling switch is responsive to said second cam means to enable motor operation only when said clutch is engaged.

7. Apparatus according to claim 6 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence, sequence means for referring sequentially to said values in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

8. Apparatus according to claim 1 in which said cam is engageable with a switch mounted to said frame one of whose switching conditions is caused by cam contact at zero tension values, and another is caused by no contact at positive tension values, and an emergency power source connectible to said motor to drive the same in said last named other switching condition, when enabled by the failure of power, whereby the consequence of concomitant tension on said line and power failure causes said emergency power source to drive said motor to pay out said line to zero tension value.

9. Apparatus according to claim 8 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence, sequence means for referring sequentially to said values in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

10. Apparatus according to claim 1 in which said tension sensing means comprises a spring having one of its ends anchored to said frame, means directing said line relative to the other end of said spring so that tension in said line determines the deflection of the spring, and a circuit element having a portion linked to said spring which portion moves as the deflection of the spring changes, said circuit element having a continuously variable parameter which thereby varies as a function of deflection of said spring.

11. Apparatus according to claim 10 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence, sequence means for referring sequentially to said values in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

12. Apparatus according to claim 11 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence, sequence means for referring sequentially to said values in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

13. Apparatus according to claim 10 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence, sequence means for referring sequentially to said values in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

14. Apparatus according to claim 1 in which said circuitry in said program means includes definition means defining desired tension values sequentially to be obtained in said sequence, sequence means for referring sequentially to said values in said definition means, and in which said motor control means includes comparator means for comparing the signal from said tension sensing means to a signal representative of a value selected by said sequence means, said motor control means assuming in response a respective condition which causes the motor to operate or not to operate to attain said selected value.

15. Apparatus for exerting traction force in traction therapy, said apparatus comprising:

a flexible line by means of which said force is to be exerted;

drive means to which said line is engaged for pulling in and paying out said line;

a motor operatively engaged to said drive means;

motor control means operatively interposed between said motor and a source of energy for driving said motor, said motor control means having a first and a second control condition for respectively causing said motor to pull in or to pay out said line, and a third control condition where it does neither;

tension sensing means responsive to tension exerted on said line to provide a signal which is proportional to the value; and

transmission means including a clutch interposed between said motor and said drive means, and a cam and a cam follower interposed between said clutch and said tension sensing means, said cam and cam follower being so constructed and arranged as to hold said clutch engaged when there is tension in said flexible line above some minimum value.

16. Apparatus according to claim 15 in which said cam is moved by said tension sensing means, and in which said follower is moved by solenoid means actuable to engage said clutch, said follower being movable by said solenoid to clear said cam, whereafter, de-energizing said solenoid while tension is on said line, causes interference of said follower and cam prevents dis-engagement of said clutch.

17. Apparatus according to claim 16 in which said clutch comprises a movable support plate, and an intermediate gear rotatably mounted to said support plate, adapted to interlink said motor and said drive means when said solenoid is energized.

18. Apparatus according to claim 15 in which said follower includes second cam means, and in which a motor-enabling switch is responsive to said second cam means to enable motor operation only when said clutch is engaged.

19. Apparatus according to claim 15 in which said cam is engageable with a switch mounted to said frame one of whose switching conditions is caused by cam contact at zero tension values, and another is caused by no contact at positive tension values, and an emergency power source connectible to said motor to drive the same in said last named other switching condition, when enabled by the failure of power, whereby the consequence of concomitant tension on said line and power failure causes said emergency power source to drive said motor to pay out said line to zero tension value.

20. Apparatus according to claim 15 in which said tension sensing means comprises a spring having one of its ends anchored to said frame, and means directing said line relative to the other end of said spring so that tension in said line determines the deflection of the spring.