Counterbalance apparatus

• US 6,026,755 A
• Filed: 02/13/1998
• Issued: 02/22/2000
• Est. Priority Date: 01/11/1996
• Status: Expired due to Term

• Current Assignee: Dennis Long
• Original Assignee: Dennis L. Long
• Inventors: Long, Dennis L.
• Primary Examiner(s): Ramirez, Ramon O.
• Assistant Examiner(s): WENTSLER, STEPHEN S
• Application Number:
  US09/024,518
• Time in Patent Office: 739 Days
• Field of Search: 108/147, 108/146, 108/145, 108/147.19, 108/50.02, 267/175, 267/177, 267/178, 267/180, 267/DIG. 1, 248/600, 248/601, 248/622, 248/623, 248/624, 248/631, 248/648, 248/651, 248/669, 248/123.11, 248/188.2, 248/188.5, 248/162.1, 248/157, 248/421, 248/405 , 248/406.1, 248/404, 248/364
• US Class Current: 108/147
• CPC Class Codes: A47B 9/02 with balancing device, e.g. by springs, by weight

Abstract

A counterbalance apparatus (10) for use in moving a work surface (102) is described. The apparatus includes an upper, lower and center member (12, 14 and 24), a pair of inner and outer cam surfaces (20, 22 and 26) and a pair of inner and outer cam followers (58, 60 and 62). The outer cam surfaces are located on the lower member. The inner cam surfaces are located on the center member. The lower member is telescopingly mounted within the upper member. The top (24A) of the center member is connected to the top (12A) of the upper member. One end of the springs (46 and 47) is mounted in the bracket (48) which is connected by connector arms (50 and 52) to the cam followers. The other end of the spring is adjacent the top of the upper member and the center member. In use, as a force is applied to move the work surface in a given direction, the center member moves into or out of the lower member. As the center member moves, the spring is compressed or decompressed and the cam followers move along the inner and outer cam surfaces. The cam followers exert a force on the cam surfaces which compensates for the force of the springs and the preadjusted force.

Claims

1. In a counterbalance apparatus, the improvement which comprises:

(a) a first member defining a longitudinal axis and having opposed ends with at least one wall between the ends;

(b) a second member slidably mounted along the first member so as to be along the longitudinal axis and having opposed ends with at least one wall between the ends of the second member;

(c) a pair of first cam surfaces located on the wall of the first member such that one first cam surface is a mirror image of the other first cam surface on opposed sides of the longitudinal axis;

(d) a pair of second cam surfaces located on the wall of the second member such that one second cam surface is a mirror image of the other second cam surface on opposed sides of the longitudinal axis wherein each of the first cam surfaces of the pair of first cam surfaces defines oppositely inclined paths relative to each of the respective second cam surfaces of the pair of second cam surfaces and wherein with the first and second members in an extended position, each of the first cam surfaces of the pair of first cam surfaces is spaced apart from each of the respective second cam surfaces of the pair of second cam surfaces with a space between them in a plane perpendicular to a plane formed by the wall of the first member and wherein each of the respective first and second cam surfaces are located one above the other along the longitudinal axis;

(e) a pair of cam followers positioned adjacent and in contact with the pairs of first and second cam surfaces in the space between each of the first and the second cam surfaces and which move in the oppositely inclined paths defined by the first and second cam surfaces; and

(f) a resilient member with opposed ends and connected at one end to the pair of cam followers and at the other end to the second member so that the first and second members are biased in the extended position and so that when the resilient member is compressed, the cam followers move along the oppositely inclined paths of the first and second cam surfaces as the first and second members are moved together to provide a counterbalance for a weight on one of the opposed ends of the first and second members.

2. The counterbalance apparatus of claim 1 wherein the pairs of first and second cam surfaces are inclined so as to provide increasing leverage so that a relatively constant force can be applied between the ends of the first and second members which are distal to each other to move the members together.

3. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other one of the ends of the dampening means.

4. The counterbalance apparatus of claim 3 wherein the resilient member is mounted around the dampening means and wherein an adjustment means is mounted on the dampening means for varying a length of and thus compression of the resilient member.

5. The counterbalance apparatus of claim 4 wherein the adjustment means is rotatable for compression and decompression of the resilient member and includes a rotatable, threaded member on the dampening means and a threaded retaining means mounted on the threaded member and wherein, the retaining means engages a portion of the second member to prevent rotation of the retaining means.

6. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the dampening means and wherein the resilient member is a coil spring mounted inside of the second member and around the dampening means so as to bias the members apart.

7. The counterbalance apparatus of claim 6 wherein the coil spring includes a first and second coil spring.

8. The counterbalance apparatus of claim 7 wherein the first and second coil springs have a different spring constant and compress at different rates.

9. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the dampening means, wherein the resilient member is a coil spring and is mounted inside of the second member and around the dampening means so as to bias the members apart and wherein the coil spring has non-linear coils along a length of the coil spring so as to require a variable force to compress the coil spring along the length.

10. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the dampening means, wherein the resilient member is a coil spring and is mounted inside of the second member and around the dampening means so as to bias the members apart and wherein an adjustment means is mounted on the dampening means for varying a length and thus compression of the coil spring.

11. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other of the ends of the dampening means, wherein the resilient member is a coil spring and is mounted inside of the second member and around the dampening means so as to bias the members apart and wherein the coil spring has non-linear coils along a length of the coil spring so as to require a variable force to compress the coil spring along the length and wherein an adjustment means is mounted on the dampening means for varying the length of and thus compression of the coil spring.

12. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one of the ends to one of the ends of the second member with the cam followers connected to the other one of the ends of the dampening means, wherein the resilient member is a coil spring and is mounted inside of the second member and around the dampening means so as to bias the members apart and wherein a rotatable adjustment means for compression or decompression of the coil spring includes a threaded member on the dampening means and a threaded retaining means mounted on the threaded member, the threaded retaining means engaging a portion of the second member which prevents rotation of the threaded retaining means.

13. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the dampening means, wherein the resilient member is a coil spring and is mounted inside of the second member and around the dampening means so as to bias the members apart, wherein the coil spring has non-linear coils along a length of the coil spring to require a variable force to compress the coil spring along the length, wherein a rotatable adjustment means for compression or decompression of the coil spring is mounted on the dampening means for varying the length of the coil spring and wherein the adjustment means includes a threaded member on the dampening means and a threaded retaining means mounted on the threaded member, the threaded retaining means engaging a portion of the second member which prevents rotation of the threaded retaining means.

14. The counterbalance apparatus of any one of claims 1 or 2 wherein a dampening means having opposed ends is connected at one of the ends to one of the ends of the second member with the cam followers connected to the other of the ends of the dampening means, and wherein the resilient member is a coil spring and is mounted inside of the second member and around the dampening means to bias the members apart, wherein the coil spring has non-linear coils along a length of the coil spring so as to require a variable force to compress the coil spring along the length, wherein a rotatable adjustment means for compression or decompression of the coil spring is mounted on the dampening means for varying the length of the coil spring, wherein the adjustment means includes a threaded member on the dampening means and a threaded retaining means mounted on the threaded member, the threaded retaining means engaging a portion of the second member to prevent rotation of the threaded retaining means and wherein the coil spring extends between the retaining means and a bracket connected to the cam followers.

15. The counterbalance apparatus of claims 1 or 2 wherein the second and first members have a rectangular cross-section.

16. The apparatus of claims 1 or 2 wherein a dampening means having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the dampening means, and wherein the resilient member is a coil spring and is mounted inside of the second member and around the dampening means to bias the members apart, wherein the coil spring has non-linear coils which require a variable force to compress the coil spring along a length of the coil spring, wherein a rotatable adjustment means for compression or decompression of the coil spring is mounted on the dampening means for varying the length of the coil spring when the members are biased apart, and wherein the adjustment means includes a threaded member on the dampening means and a threaded retaining means mounted on the threaded member, the retaining means engaging a portion of the second member wherein the coil spring has ends which extend between the retaining means and a bracket connected to the cam followers and wherein the second and first tubular members have a rectangular cross-section.

17. The counterbalance apparatus of any one of claims 1 or 2 wherein the one end of the resilient member is mounted in a bracket which is connected by a pair of pivotable connector arms to the pair of cam followers.

18. The counterbalance apparatus of any one of claims 1 or 2 wherein the first member has a front wall parallel to and spaced apart from a back wall and wherein a pair of front first cam surfaces are mounted on the front wall and a pair of back first cam surfaces are mounted on the back wall.

19. The counterbalance apparatus of claim 18 wherein the cam followers include front and back first cam rollers which contact and move along the front and back first cam surfaces respectively, and second cam rollers spaced between the front and back first cam rollers which contact and move respectively along the second cam surfaces.

20. The counterbalance apparatus of any one of claims 1 or 2 wherein the cam followers include first cam rollers which respectively contact and move along the first cam surfaces and second cam rollers which respectively contact and move along the second cam surfaces.

21. A work station with a counterbalance movable work surface and a support means for the work surface of the work station with a counterbalance apparatus within the support means for movement of the work surface which comprises:

(a) the counterbalance apparatus including a first member defining a longitudinal axis and having opposed ends with at least one wall between the ends;

a second member slidably mounted along the first member so as to be along the longitudinal axis and having opposed ends with at least one wall between the ends of the second member;

a pair of first cam surfaces located on the wall of the first member such that one first cam surface is a mirror image of the other first cam surface on opposed sides of the longitudinal axis;

a pair of second cam surfaces located on the wall of the second member such that one second cam surface is a mirror image of the other second cam surface on opposed sides of the longitudinal axis wherein each of the first cam surfaces of the pair of first cam surfaces defines oppositely inclined paths relative to each of the respective second cam surfaces of the pair of second cam surfaces and wherein with the first and second members in an extended position, each of the first cam surfaces of the pair of first cam surfaces is spaced apart from each of the respective second cam surfaces of the pair of second cam surfaces with a space between them in a plane perpendicular to a plane formed by the wall of the first member and wherein each of the respective first and second cam surfaces are located one above the other along the longitudinal axis;

a pair of cam followers positioned adjacent and in contact with the pairs of first and second cam surfaces in the space between each of the first and the second cam surfaces and which move in the oppositely inclined paths defined by the first and second cam surfaces; and

a resilient member with opposed ends and connected at one end to the pair of cam followers and at the other end to the second member so that the first and second members are biased in the extended position and so that when the resilient member is compressed, the cam followers move along the oppositely inclined paths of the first and second cam surfaces as the first and second members are moved together to provide a counterbalance for a weight on one of the opposed ends of the first and second members; and

(b) locking means adjacent the counterbalance apparatus for securing the work surface of the work station against movement.

22. The work station of claim 21 wherein the first and second cam surfaces are inclined so as to provide increasing leverage so that a relatively constant force can be applied between the ends of the members which are distal to each other to move the members together.

23. The work station of any one of claims 21 or 22 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other one of the ends of the damper.

24. The work station of any one of claims 21 or 22 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the damper and wherein the resilient member is a coil spring mounted inside of the second member and around the damper so as to bias the members apart.

25. The work station of any one of claims 21 or 22 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the damper, wherein the resilient member is a coil spring and is mounted inside of the second member and around the damper so as to bias the members apart and wherein the coil spring has non-linear coils along a length of the coil spring so as to require a variable force to compress the coil spring along the length.

26. The work station of any one of claims 21 or 22 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the damper wherein the resilient member is mounted around the damper, and wherein an adjustment means is mounted on the damper for varying a length of and thus compression of the resilient member.

27. The work station of any one of claims 21 or 22 wherein the work surface has a first and second support means and wherein a first and second counterbalance apparatus is mounted in the first and second support means, respectively.

28. The work station of claim 27 wherein the first and second counterbalance apparatuses are connected together by an alignment rod.

29. The work station of claim 28 wherein the rod is connected to an alignment mechanism located in the first counterbalance apparatus and wherein the alignment mechanism rotates the rod in response to raising or lowering of the work surface to ensure that the second counterbalance apparatus raises and lowers at a same rate as the first counterbalance apparatus.

30. The work station of claim 29 wherein the alignment mechanism includes a chain, a sprocket and a bracket with the sprocket mounted on an end of the rod located in the first counterbalance apparatus and the bracket mounted at an end of a second member of the first counterbalance apparatus and wherein the chain extends around the sprocket and around the bracket to form a loop and wherein the chain is fastened to the second member such that when the second member raises or lowers, the chain moves with the second member which rotates the sprocket and the rod.

31. The work station of claim 28 wherein the locking means is mounted on the alignment rod to prevent the work surface from being raised or lowered.

32. The work station of claim 31 wherein the locking means is a spring wrap brake.

33. The work station of claim 31 wherein the locking means is released by a hand activated lever.

34. The work station of claim 27 wherein an adjustment means is mounted adjacent one end of the resilient member for each of the first and second counterbalance apparatuses.

35. The work station of claim 34 wherein a first sprocket is mounted on the adjustment means of the first counterbalance apparatus and is connected by a chain to a second sprocket mounted on the adjustment means of the second counterbalance apparatus such that an adjustment of a compression of the resilient member of the first counterbalance apparatus results in a corresponding adjustment of a compression of a resilient member of the second counterbalance apparatus.

36. In a counterbalance apparatus, the improvement which comprises:

(a) a first member defining a longitudinal axis and having opposed ends with at least one wall between the ends;

(b) a second member slidably mounted along the first member so as to be along the axis and having opposed ends with at least one wall between the ends of the second member;

(c) a pair of first cams attached to the first member, a pair of second cams attached to the second member, each of the cams extending between the first member and the second member, each of the cams of the pair of first cams comprises a corresponding first cam surface, each of the cams of the pair of second cams comprises a corresponding second cam surface, each of the first cam surfaces of the pair of first cams define oppositely inclined paths relative to each of the respective second cam surfaces of the pair of second cams;

(d) cam followers which move in the oppositely inclined paths with respect to the longitudinal axis and wherein at least one of the second member or first member is movable along the longitudinal axis relative to the other of the second member or first member to move the members together; and

(e) a force storage mechanism with opposed ends which is connected at one end to the cam followers and at the other end to one end of the second member so as to bias the members apart.

37. The counterbalance apparatus of claim 36 wherein the first and second cam surfaces are inclined so as to provide increasing leverage so that a relatively constant force can be applied between the ends of the members which are distal to each other to move the members together.

38. The counterbalance apparatus of any one of claims 36 or 37 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other one of the ends of the damper.

39. The counterbalance apparatus of any one of claims 36 or 37 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the damper and wherein the force storage mechanism is a coil spring mounted inside of the second member and around the damper so as to bias the members apart.

40. The counterbalance apparatus of any one of claims 36 or 37 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the damper, wherein the force storage mechanism is a coil spring and is mounted inside of the second member and around the damper so as to bias the members apart and wherein the coil spring has non-linear coils along a length of the coil spring so as to require a variable force to compress the coil spring along the length.

41. The counterbalance apparatus of any one of claims 36 or 37 wherein a damper having opposed ends is connected at one end to one of the ends of the second member with the cam followers connected to the other end of the damper wherein the force storage mechanism is mounted around the damper and wherein an adjustment means is mounted on the damper for varying a length of and thus compression of the force storage mechanism.