Dynamic splint

• US 6,001,075 A
• Filed: 12/12/1997
• Issued: 12/14/1999
• Est. Priority Date: 12/12/1997
• Status: Expired due to Term

• Current Assignee: Ex. P.H.
• Original Assignee: Ex. P.H.
• Inventors: Ashford, Dennis L., Clemens, Leonard M., Rembold, William T.
• Primary Examiner(s): CLARK, JEANNE MARIE
• Application Number:
  US08/989,379
• Time in Patent Office: 732 Days
• Field of Search: 602/5, 602/16, 602/20, 602/21, 602/23, 602/26, 601/23, 601/33
• US Class Current: 602/16
• CPC Class Codes: A61F 2005/0139 geared
• CPC Class Codes: A61F 2005/0179 with spring means
• CPC Class Codes: A61F 5/0123 for the knees A61F5/0106 takes precedence

Abstract

A dynamic splint for a joint of a limb undergoing rehabilitation. The splint having a pair of elements each comprising a first tubular strut, a second lever-like strut and an intermediate gear housing mounted on one end of the first strut. A first toothed gear is rotatively mounted on a first shaft in the gear housing and is located adjacent the first strut. A second cooperating toothed gear is rotatively mounted on a second shaft in the gear housing adjacent the second strut. The first gear is missing at least one tooth. The second gear is missing a plurality of teeth in a row. The second strut is pivoted to the second shaft and is attached to the second gear at one of a plurality of selectable positions thereabout. A cam wheel is rotatively mounted on the first shaft and is affixed to the first gear. A compression spring is mounted in the tubular first strut. A cable is affixed at one end to the cam wheel and is operatively adjustably affixed to the spring. The cam wheel is so configured that the assembly of the spring, cable, cam wheel and first gear apply an adjustable constant torque in one of a clockwise or counterclockwise direction to the second gear and second strut only when the teeth of the gears are meshed. The second strut and second gear are rotatable throughout the normal range of motion. The gears are meshed only in the passive portion of the normal full range of motion of the joint as determined by the attachment position of the second strut on the second gear.

Claims

1. A dynamic splint for applying a constant pre-adjusted torque across a hinged joint of a patient, the joint having a normal full range of motion divided into an active portion through which the patient can pivot the joint and a passive portion through which the patient cannot pivot the joint due to connective tissue contracture, said dynamic splint comprising a pair of spaced-apart side frame assemblies, said side frame assemblies each having a first strut;

a gear housing mounted on one end of said first strut;

a first gear rotatably mounted in said gear housing adjacent to said first strut, said first gear having a plurality of teeth and a first missing teeth portion of said first gear wherein at least one of said teeth is missing;

a second gear rotatably mounted in said gear housing adjacent to said first gear, said second gear having a plurality of teeth and a second missing teeth portion of said second gear having a plurality of adjacent teeth missing, wherein said teeth of said first gear and said teeth of said second gear mesh when said first gear and said second gear are rotated in said gear housing to position said teeth of said first gear adjacent to said teeth of said second gear and said teeth of said first gear disengage from said teeth of said second gear when said first gear and said second gear are rotated in said gear housing to position said first missing teeth portion of said first gear adjacent to said second missing teeth portion of said second gear;

a second strut having one end pivotally mounted in said gear housing and pivotable through the full range of motion of the joint, said second strut releasably attached to said second gear at a selected one of a plurality of positions on said second gear, said selected one of a plurality of positions corresponding to the transition point between the active and passive portions of the full range of motion of the joint, wherein said teeth of said first gear and said teeth of said second gear mesh as said second strut is pivoted through the passive portion of the full range of motion of the joint and said teeth of said first gear and said teeth of said second gear are disengaged as said second strut is pivoted through the active portion of the full range of motion of the joint;

bias means operably connected to said first gear for exerting a pre-adjusted torque on said first gear, whereby the pre-adjusted torque is constantly applied to said second strut through the passive portion of the full range of movement of the joint and no torque is applied to said second strut through the active portion of the full range of movement of the joint; and

a first cuff assembly supported by said first struts of said side frame assemblies and a second cuff assembly supported by said second struts of said side frame assemblies.

2. The dynamic splint of claim 1 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames.

3. The dynamic splint of claim 1 comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

4. The dynamic splint of claim 1 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames;

and comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

5. The dynamic splint of claim 1 comprising a plurality of aligned range of motion perforations provided in said housing about the periphery of said second gear and a pin for extension through a selected pair of said range of motion perforations for stopping said second strut at a selected point in the full range of motion of the joint.

6. The dynamic splint of claim 5 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames.

7. The dynamic splint of claim 5 comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

8. The dynamic splint of claim 5 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames;

and comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

9. The dynamic splint of claim 5 comprising a strut perforation provided in said second strut and wherein said pin can be extended through a selected pair of said range of motion perforations and said strut perforation for locking said second strut at a selected point in the full range of motion of the joint.

10. The dynamic splint of claim 9 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames.

11. The dynamic splint of claim 9 comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

12. The dynamic splint of claim 9 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames;

and comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

13. A dynamic splint for applying a constant pre-adjusted torque across a hinged joint of a patient, the hinged joint having a normal full range of motion divided into an active portion through which the patient can pivot the joint and a passive portion through which the patient cannot pivot the joint due to connective tissue contracture, said dynamic splint comprising a pair of substantially parallel side frame assemblies, said side frame assemblies each having a tubular first strut;

a gear housing mounted on one end of said first strut;

a first gear rotatably mounted in said gear housing adjacent to said first strut, said first gear having a plurality of teeth and a first missing teeth portion of said first gear wherein at least one of said teeth is missing;

a second gear rotatably mounted in said gear housing adjacent to said first gear, said second gear having a plurality of teeth and a second missing teeth portion of said second gear having a plurality of adjacent teeth missing, wherein said teeth of said first gear and said teeth of said second gear mesh when said first gear and said second gear are rotated in said gear housing to position said teeth of said first gear adjacent to said teeth of said second gear and said teeth of said first gear disengage said teeth of said second gear when said first gear and said second gear are rotated in said gear housing to position said first missing teeth portion of said first gear adjacent to said second missing teeth portion of said second gear;

a second strut having one end pivotally mounted in said gear housing and pivotable through the full range of motion of the joint, said second strut releasably attached to said second gear at a selected one of a plurality of positions corresponding to the transition point between the active and passive portions of the full range of motion of the joint, wherein said teeth of said first gear and said teeth of said second gear mesh as said second strut is pivoted through the passive portion of the full range of motion of the joint and said teeth of said first gear and said teeth of said second gear are disengaged as said second strut is pivoted through the active portion of the full range of motion of the joint;

a cam wheel rotatably mounted with said first gear, a cable attached at one end to said cam wheel and an adjustable compression spring mounted in said first strut and attached to the other end of said cable for exerting a pre-adjusted torque on said first gear, whereby the pre-adjusted torque is constantly applied to said second strut throughout the passive portion of the full range of movement of the joint and no torque is applied to said second strut throughout the active portion of the full range of movement of the joint; and

a first cuff assembly supported by said first strut of said side frame assemblies and a second cuff assembly supported by said second struts of said side frame assemblies.

14. The dynamic splint of claim 13 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames.

15. The dynamic splint of claim 13 comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

16. The dynamic splint of claim 13 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames;

and comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said pair of cuff mounting members.

17. The dynamic splint of claim 13 comprising a plurality of aligned range of motion perforations provided in said housing about the periphery of said second gear and a pin for extension through a selected pair of said range of motion perforations and stopping said second strut at a selected point in the full range of motion of the joint.

18. The dynamic splint of claim 17 comprising a strut perforation provided in said second strut and wherein said pin can be extended through a selected pair of said range of motion perforations and said strut perforation for locking said second strut at a selected point in the full range of motion of the joint.

19. The dynamic splint of claim 18 comprising a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, and wherein said first cuff assembly is mounted between said pair of cuff mounting frames;

and comprising a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and wherein said second cuff assembly is mounted between said second pair of cuff mounting members.

20. A dynamic splint for applying a constant pre-adjusted torque across a hinged joint of a patient, the joint having a normal full range of motion divided into an active portion through which the patient can pivot the joint and a passive portion through which the patient cannot pivot the joint due to connective tissue contracture, said dynamic splint comprising a pair of spaced-apart, substantially parallel side frame assemblies, said side frame assemblies each having a tubular first strut;

a gear housing mounted on one end of said first strut;

a first gear rotatably mounted in said gear housing adjacent to said first strut, said first gear having a plurality of teeth and a first missing teeth portion of said first gear wherein at least one of said teeth is missing;

a second gear rotatably mounted in said gear housing adjacent to said first gear, said second gear having a plurality of teeth and a second missing teeth portion of said second gear having a plurality of adjacent teeth missing, wherein said teeth of said first gear and said teeth of said second gear mesh when said first gear and said second gear are rotated in said gear housing to position said teeth of said first gear adjacent to said teeth of said second gear and said teeth of said first gear disengage said teeth of said second gear when said first gear and said second gear are rotated in said gear housing to position said first missing teeth portion of said first gear adjacent to said second missing teeth portion of said second gear;

a second strut having one end pivotally mounted in said gear housing and pivotable through the full range of motion of the joint, said second strut releasably attached to said second gear at a selected one of a plurality of positions corresponding to the transition point between the active and passive portions of the joint, wherein said teeth of said first gear and said teeth of said second gear mesh as said second strut is pivoted through the passive portion of the full range of motion of the joint and said teeth of said first gear and said teeth of said second gear are disengaged as said second strut is pivoted through the active portion of the full range of motion of the joint;

a cam wheel rotatably mounted with said first gear, a cable attached at one end to said cam wheel an adjustable compression spring mounted in said first strut, a threaded compression nut provided in said first strut for compressing said compression spring against said housing and a threaded bolt attached to the other end of said cable and threaded through said compression nut for exerting a pre-adjusted torque on said first gear, whereby the pre-adjusted torque is constantly applied to said second strut through the passive portion of the full range of motion of the joint and no torque is applied to said second strut through the active portion of the full range of motion of the joint;

a plurality of aligned range of motion perforations provided in said housing about the periphery of said second gear and a pin for extension through a selected pair of said range of motion perforations for stopping said second strut at a selected point in the full range of motion of the joint, a strut perforation provided in said second strut and wherein said pin can be extended through a selected pair of said range of motion perforations and said strut perforation for locking said second strut at a selected point in the full range of motion of the joint; and

a pair of cuff mounting frames provided in facing relationship on said first struts, respectively, a first cuff assembly mounted between said pair of cuff mounting frames, a pair of cuff mounting members provided in facing relationship on said second struts, respectively, and a second cuff assembly mounted between said pair of cuff mounting members.