Height adjustable table

• US 9,038,549 B1
• Filed: 03/14/2013
• Issued: 05/26/2015
• Est. Priority Date: 06/01/2012
• Status: Active Grant

• Current Assignee: Humanscale Corporation
• Original Assignee: Humanscale Corporation
• Inventors: Zebarjad, Hamid
• Primary Examiner(s): ROHRHOFF, DANIEL J
• Application Number:
  US13/827,333
• Time in Patent Office: 803 Days
• Field of Search: 108/37, 108/33, 108/144.11, 108/147, 108/147.19, 108/136, 248/188.2, 248/161, 248/404, 248/157, 248/162.1, 248/123.11, 248/122.2
• US Class Current: 108/147
• CPC Class Codes: A47B 2200/0052 with two telescopic parts
• CPC Class Codes: A47B 9/02 with balancing device, e.g. by springs, by weight
• CPC Class Codes: A47B 9/12 with flexible height-adjusting means, e.g. rope, chain
• CPC Class Codes: A47B 9/20 Telescopic guides

Abstract

A height adjustable table, which has a constant-force counterbalance mechanism integrated into a top assembly of the table is disclosed. The height adjustable table can include a top assembly supported by a base assembly, which can include right and left telescoping leg assemblies. The top assembly can include a work surface supported by a housing. A counterbalance mechanism, which can include a spring coupled to a snail cam pulley, can be mounted within the housing. A synchronized lift mechanism, which can include at least two bands operatively engaged with a pulley system disposed within the right and left telescoping leg assemblies, can be operatively coupled to the snail cam pulley such that the counterbalance force provided by the counterbalance mechanism is transmitted to the synchronized lift mechanism.

Claims

1. A height adjustable table comprising:

a top assembly comprising a housing and a work surface supported on the housing;

a constant-force counterbalance mechanism disposed within the housing;

a base assembly, which supports the top assembly, the base assembly comprising a first telescoping leg assembly and a second telescoping leg assembly, the first telescoping leg assembly and the second telescoping leg assembly each comprising an outside leg and an inside leg having a variable overlap to accommodate height adjustment of the top assembly; and

a preload mechanism positioned within the housing and operatively coupled to the constant-force counterbalance mechanism, the preload mechanism comprising;

a gearbox having a worm wheel;

a worm meshed with the worm wheel to form a worm drive;

a hub coupled to the worm wheel;

a preload cable having a first end attached to the hub and a second end attached to the constant-force counterbalance mechanism; and

a handle coupled to the worm drive.

2. The height adjustable table of claim 1, wherein the constant-force counterbalance mechanism comprises:

a tension spring for providing a counter-weight force, the tension spring having a first end and a second end;

a snail cam pulley comprising a snail cam wheel secured to a mount by an axle, the snail cam wheel having a cam track and a lift track; and

a snail cable coupling the second end of the tension spring to the cam track of the snail cam wheel.

3. The height adjustable table of claim 2, further comprising a synchronized lift mechanism operatively coupled to the constant-force counterbalance mechanism to provide synchronized lifting or lowering of the top assembly, the synchronized lift mechanism comprising:

a first pulley assembly and a second pulley assembly, the first pulley assembly associated with the first telescoping leg assembly and the second pulley assembly associated with the second telescoping leg assembly;

a first band and a second band each operatively coupled to the first and second pulley assemblies; and

a lift cable having a first end attached to the lift track of the snail cam wheel and a second end attached to the inside leg of one of the first and second telescoping leg assemblies.

4. The height adjustable table of claim 2, further comprising a load indicator coupled to the first end of the tension spring.

5. The height adjustable table of claim 3, wherein each of the first and second pulley assemblies comprises:

at least one upper pulley;

at least one lower pulley; and

a shaft coupling the at least one lower pulley to the at least one upper pulley, wherein the shaft is suspended within an internal cavity of the respective telescoping leg assembly.

6. The height adjustable table of claim 5, wherein a first end of the second band is connected to the inside leg of the first telescoping leg assembly and extends around the at least one upper pulley of the first pulley assembly, across the housing, around the at least one upper pulley of the second pulley assembly, around the at least one lower pulley of the second pulley assembly, and connects at a second end to the inside leg of the second telescoping leg assembly.

7. The height adjustable table of claim 3, further comprising a lock mechanism positioned within the housing for fixing the top assembly at a desired height, the lock mechanism comprising:

a lock assembly having a release position and a lock position, the lock assembly having upper and lower lock members positioned on opposing sides of at least one of the first and second bands and configured to prevent height adjustment of the top assembly when the lock assembly is positioned in the lock position; and

a release assembly having an actuation member, a safety spring, a first cable connecting the actuation member to the safety spring, and a second cable connecting the safety spring to the lock assembly.

8. The height adjustable table of claim 5, wherein the lift cable extends from the lift track around the at least one upper pulley of the first pulley assembly and around the at least one lower pulley of the first pulley assembly, and attaches to the inside leg of the first telescoping assembly.

9. The height adjustable table of claim 5, wherein the lift cable extends from the lift track around the at least one upper pulley of the second pulley assembly, around the at least one lower pulley of the second pulley assembly, and attaches to the inside leg of the second telescoping assembly.

10. The height adjustable table of claim 6, wherein a first end of the first band is connected to the inside leg of the second telescoping leg assembly and extends around the at least one upper pulley of the second pulley assembly, across the housing, around the at least one upper pulley of the first pulley assembly, around the at least one lower pulley of the first pulley assembly, and connects at a second end to the inside leg of the first telescoping leg assembly.

11. The height adjustable table of claim 1, wherein the preload mechanism further comprises a torque limiter positioned between the handle and the worm to decouple the handle from the worm drive when a torque exerted by the handle on the worm drive exceeds a predetermined amount.

12. A height adjustable table comprising:

a base assembly comprising a first telescoping leg assembly and a second telescoping leg assembly, each of the first telescoping leg assembly and the second telescoping leg assembly comprising;

an outside leg; and

an inside leg,

one of the outside and inside legs being fixedly coupled to a stationary foot, the outside and inside legs having a variable overlap;

a top assembly supported by the base assembly, the top assembly comprising a work surface mounted to a housing;

a constant-force counterbalance mechanism positioned within the housing; and

a synchronized lift mechanism operatively coupled to the constant-force counterbalance mechanism to provide synchronized lifting and lowering of the top assembly relative to the stationary feet of the base assembly, the synchronized lift mechanism comprising;

a first pulley assembly positioned within the first telescoping leg assembly;

a second pulley assembly positioned within the second telescoping leg assembly;

a first band operatively coupled to the first and second pulley assemblies;

a second band operatively coupled to the first and second pulley assemblies; and

a lift cable having a first end attached to the constant-force counterbalance mechanism and a second end attached to the inside leg of one of the first and second telescoping leg assemblies.

13. The height adjustable table of claim 12, wherein the constant-force counterbalance mechanism comprises:

a snail cam pulley including a snail cam wheel secured to a mount by an axle, the snail cam wheel having a cam track and a lift track;

a tension spring having a first end and a second end; and

a snail cable coupling the second end of the tension spring to the cam track of the snail cam wheel.

14. The height adjustable table of claim 12, further comprising:

a preload mechanism positioned within the housing and operatively coupled to the constant-force counterbalance mechanism for modulating a counter-weight force provided by the constant-force counterbalance mechanism.

15. The height adjustable table of claim 14, further comprising a lock mechanism positioned within the housing for fixing the top assembly at a desired height, the lock mechanism comprising a lock assembly having a release member and upper and lower lock members positioned on opposing sides of at least one of the first and second bands to prevent height adjustment of the top assembly.

16. The height adjustable table of claim 14, wherein the preload mechanism comprises:

a gearbox having a worm wheel;

a worm meshed with the worm wheel to form a worm drive;

a hub coupled to the worm wheel;

a preload cable having a first end attached to the hub and a second end attached to the first end of the tension spring; and

a handle coupled to the worm drive.