Lift mechanism based on torque equalization principles

• US 20040250635A1
• Filed: 03/03/2004
• Published: 12/16/2004
• Est. Priority Date: 05/20/2003
• Status: Abandoned Application

• Current Assignee: Ergotron Incorporated (Melrose Industries Plc)
• Original Assignee: Ergotron Incorporated (Melrose Industries Plc)
• Inventors: Lindblad, Shaun C., Trish, Scott, Ergun, Mustafa A., Sweere, Harry C., Al-Zebdeh, Khalid, Overn, H. Karl
• Application Number:
  US10/792,467
• Publication Number:
  US 20040250635A1
• Time in Patent Office: Days
• US Class Current: 74/1R
• CPC Class Codes: F16M 11/10 around a horizontal axis F16M11/12 takes precedence
• CPC Class Codes: F16M 11/30 with co-moving side-struts
• CPC Class Codes: F16M 2200/048 for balancing translational movement of the undercarriage
• CPC Class Codes: Y10T 74/22 Miscellaneous

Abstract

Methods and apparatus for providing an adjustable balancing force are provided. This mechanism can be used as a lifting force, a counter balancing mechanism or as a horizontal or other force mechanism. The force can be designed to be constant or variable over the range of motion by properly calculating the shape of the cam member. A balancing mechanism in accordance with the present invention includes a wheel comprising a pulley member and a cam member. A first cable connects the cam member of the wheel to a energy source for biasing the wheel to rotate in a first direction. A second cable is connected to the pulley member of the wheel for communicating a balancing or load force to the wheel. In some useful embodiments of the present invention, the cam member is shaped and positioned so that a torque applied to the wheel by the first cable is substantially constant while a force applied to the wheel by the first cable varies.

Claims

1. An apparatus, comprising:

a fixed component and a movable component disposed in sliding or rolling engagement with one another;

a wheel pivotally supported by one of the components; and

the wheel comprising a pulley member and a cam member.

2. The apparatus of claim 1, further comprising a first cable connecting the cam member of the wheel to an energy source for biasing the wheel to rotate in a first direction.

3. The apparatus of claim 2, wherein the energy source comprises a spring.

4. The apparatus of claim 2, wherein the energy source comprises a spring selected from the group consisting of torsion springs, extension springs and compression springs.

5. The apparatus of claim 1, further comprising a second cable connecting the pulley member to the other of the components so that the wheel rotates when the movable component is moved relative to the fixed component.

6. The apparatus of claim 1, wherein the cam member is shaped and positioned so that a torque applied to the wheel by the first cable is substantially constant while a force applied to the cam member by the first cable varies.

7. The apparatus of claim 1, wherein the cam member is shaped and positioned so that a torque applied to the wheel by the first cable varies in accordance with a predetermine force profile.

8. The apparatus of claim 1, wherein:

the apparatus comprises a first cable connecting the cam member of the wheel to an energy source for biasing the wheel to rotate in a first direction; and

the cam member is shaped and positioned so that a torque applied to the wheel by the first cable is substantially constant or varied in a pre-determined manner while an output of the energy source varies.

9. The apparatus of claim 8, wherein the energy source comprises a spring and the output of the energy source varies as a function of a deflection of the spring.

10. The apparatus of claim 1, wherein the cam member is shaped and positioned so that the first cable contacts the cam member at a first intersection disposed a first distance from the pivot axis when the wheel is disposed in a first orientation;

and

the first cable contacts the cam member at a second intersection disposed a second distance from the pivot axis when the wheel is disposed in a second orientation.

11. The apparatus of claim 1, wherein the cam member is shaped so that the bias urging the wheel to rotate in the first direction is substantially constant or varied in a pre-determined manner as an output of a energy source changes.

12. The apparatus of claim 1, wherein an effective radius of the cam member varies as a function of the angular orientation of the wheel.

13. The apparatus of claim 1, wherein an effective radius of the cam member varies as a function of an output of an energy source.

14. The apparatus of claim 1, wherein:

the apparatus comprises a first cable connecting the cam member of the wheel to an energy source for biasing the wheel to rotate in a first direction; and

the apparatus includes an adjustment system adapted to vary an output of the energy source.

15. The apparatus of claim 14, wherein the energy source comprises a spring.

16. The apparatus of claim 14, wherein the energy source comprises a spring selected from the group consisting of torsion springs, extension springs and compression springs.

17. The apparatus of claim 16, wherein the adjustment system comprises a first spring plate coupled to a first end of a spring and a second spring plate coupled to a second of a spring.

18. The apparatus of claim 17, wherein the screw is capable of moving the first spring plate and the second spring plate relative to one another.

19. The apparatus of claim 17, wherein the adjustment system comprises a screw capable of varying a distance between the first spring plate and the second spring plate.

20. An apparatus, comprising:

a wheel pivotally supported by a first component;

the wheel comprising a pulley member and a cam member;

a first cable extending between the cam member of the wheel and a energy source so that the wheel is biased to rotate in a first direction;

a second cable extending between the pulley member and a second component;

the cam member being shaped so that a torque applied to the wheel by the second cable is substantially constant or varied in a pre-determined manner while a deflection of the energy source vanes.

21. The apparatus of claim 20, wherein the pulley member defines a first cable path and the cam member defines a second cable path.

22. The apparatus of claim 20, wherein the first cable path has a first radius and the second cable path has a second radius.

23. The apparatus of claim 20, wherein the second radius of the second cable path varies as a function of an angular orientation of the wheel.

24. The apparatus of claim 20, wherein the second radius of the second cable path varies as a function of a deflection of the energy source.

25. The apparatus of claim 20, further including an adjustment screw adapted to vary a pre-load on the energy source.

26. The apparatus of claim 20, further including at least one guide for guiding relative motion between the second component and the first component.

27. A pivot mechanism, comprising:

a first structural member;

a second structural member pivotally coupled to the first structural member;

a torsion spring having a first leg engaging the first structural member; and

a second leg of the torsion spring engaging the second structural member.