Chair with arm mounted motion control

• US 5,308,142 A
• Filed: 01/23/1992
• Issued: 05/03/1994
• Est. Priority Date: 01/23/1992
• Status: Expired due to Term

• Current Assignee: Steelcase Development Inc.
• Original Assignee: Steelcase Incorporated
• Inventors: Forslund, Carl V. III, Faiks, Frederick S., Feldpausch, Thomas G.
• Primary Examiner(s): Brittain, James R.
• Application Number:
  US07/824,571
• Time in Patent Office: 831 Days
• Field of Search: 297/286-288, 297/297, 297/300, 297/359, 297/457, 297/285
• US Class Current: 297/286
• CPC Class Codes: A47C 7/441 with adjustable elasticity
• CPC Class Codes: A47C 7/445 with bar or leaf springs

Abstract

A chair is provided with a frame defining a curved arm support, a seat supported in the frame, and a back. An arm member is movably mounted on the arm support and operatively connected to the back so that movement of the back between upright and reclined positions is controlled by the arm member and arm support. A resilient spring is operatively connected to the back to bias the back towards an upright position. In one embodiment, the resilient spring encompasses the curved arm support and provides support for a seated user'"'"'s arm. In another embodiment, an arm cap covers the resilient spring. Optionally, the arm cap slideably rides on roller bearings over the curved arm support. In another embodiment, the curved arm support and arm member are telescopingly arranged, and the resilient spring is operably placed therein. Another embodiment includes first and second springs, the second springs being disengageable to produce discrete selectable levels of bias force for biasing the back toward the upright position. In another embodiment, the resilient spring is continuously adjustable, and includes a control mechanism including opposing springs that slide on a pivotable actuator arms thus creating a variable torque arm which is adjustable to vary the resulting bias force on the chair back.

Claims

1. A chair comprising:

a frame defining a curved arm support;

a seat supported on said frame;

a back;

an arm member movably mounted on said curved arm support, said arm member being operatively connected to said back and guided by said curved arm support so that movement of said back from an upright position to a reclined position is controlled by said arm member and said curved arm support; and

resilient means operatively connected to said back for resiliently biasing said back towards said upright position, said resilient means providing a static preload force and a dynamic biasing force on said back when reclined, and including release means for selectively changing one of said static preload force and said dynamic biasing force of said resilient means as said back is reclined.

2. A chair as defined by claim 1 wherein said resilient means comprises:

a spring having an end operably connected to said arm member; and

connecting means attached to another end of said spring for connecting said another end to said arm support.

3. A chair as defined by claim 2 wherein said spring includes an elastic band of polymeric material.

4. A chair as defined by claim 1 wherein said seat is movably connected to said frame at a first connection and said seat and back are operably interconnected at a second connection whereby said arm member and arm support in cooperation with said frame control the movement of said seat as said back is moved.

5. A chair as defined by claim 1 including an arm cap with an upper support surface for supporting a person'"'"'s arm thereon, and wherein said resilient means is covered at least in part by said arm cap.

6. A chair as defined by claim 1 including a shell forming said seat and back, said shell including an intermediate portion connecting said seat and back, said intermediate portion being flexible so as to permit relative movement between said back and said seat.

7. A chair as defined by claim 1 wherein said seat is movably supported in said frame and said resilient means is operatively connected to said seat.

8. A chair as defined by claim 7 wherein said resilient means includes leaf springs operably mounted to said seat and said back.

9. A chair as defined by claim 1 wherein said resilient means includes first and second resilient means, said second resilient means being operably attached to said release means.

10. A chair as defined by claim 9 wherein said release means includes a hook and catch arrangement with one of said hook and said catch being associated with said second resilient means and the other of said hook and said catch being associated with said frame, said hook and said catch being engageable to operatively engage said second resilient means and being disengageable to operatively disengage said second resilient means.

11. A chair as defined by claim 10 wherein said second resilient means includes a spring operatively mounted to said curved arm support and operatively interconnected between said back and said frame, and said release means disconnects said spring from one of said back and said frame.

12. A chair as defined by claim 1 wherein said resilient means is preloaded to provide an initial level of support before said back begins to recline.

13. A chair as defined by claim 1 wherein said resilient means includes a spring, and further includes an actuator arm operably connected to said frame an said spring, said spring biasing said actuator arm in a given direction.

14. A chair as defined by claim 13 wherein said actuator arm pivots on said frame defining as axis of rotation, and said spring creates a torque on said actuator arm about said axis.

15. A chair as defined by claim 14 including means for adjusting the biasing force of said resilient means on said back.

16. A chair as defined by claim 15 wherein said spring and actuator arm define a torque arm on said actuator arm about said axis, and said means for adjusting the tension on said actuator arm includes means for moving one of said spring and said actuator arm to change said torque arm on said actuator arm, hence changing the biasing force on said back.

17. A chair as defined by claim 16 including a threaded shaft and nut operably connected to said spring for slideably moving said spring relative to said actuator arm.

18. A chair as defined by claim 13 wherein said resilient means includes a pair of said springs and actuator arms each respective pair defining a torque arm, and said springs are slideable relative to said actuator arm so as to vary said torque arm on said actuator arm, thereby changing the biasing force on said back.

19. A chair as defined by claim 1 wherein said resilient means includes a spring located remote from said back and said curved arm support, and a strap operably connecting said spring to said chair back.

20. A chair as defined by claim 19 wherein said frame includes a cross brace, and said spring is located in said cross brace.

21. A chair as defined by claim 20 wherein said resilient means includes a actuator arm operably connected to said strap, and said spring is operably connected to said actuator arm and frame to bias said actuator arm and in turn said strap in a given desired direction.

22. A chair comprising:

a frame including armrests;

a seat supported on said frame;

a tiltable movably supported on said frame and movable between upright and reclined positions;

a control mechanism including guide means located on said armrests for directing the path of movement of said back during movement between said upright and reclined positions, and further including resilient means for biasing said back towards said upright position, said resilient means being associated with said armrests and operably connected to said guide means; and

adjustment means for varying the biasing force of said resilient means.

23. A chair as defined in claim 22 including a leaf spring operably mounted to said seat and said back.

24. A chair as defined in claim 22 wherein said energy source is preloaded to provide an initial level of support before said back begins to recline.

25. A chair as defined in claim 22 wherein said resilient means includes first and second resilient means, and further includes release means for releasing said second resilient means.

26. A chair as defined by claim 25 wherein said release means is located on said armrests.

27. A chair as defined in claim 22 wherein said frame includes cross brace, and said adjustment means is mounted on said cross brace.

28. A chair as defined in claim 27 wherein said frame includes tubular members defining an interior, and said resilient means includes a strap operably connected to said back and extending through said tubular member interior to said cross brace.

29. A chair as defined in claim 22 wherein said adjustment means includes an actuator arm pivotally connected to said frame, a spring operably connected to said frame, said spring and said actuator arm defining a torque arm on said actuator arm, and said adjustment means permits varying the length of said torque arm.

30. A chair as defined in claim 29 wherein said frame includes a tubular cross brace, and said adjustment means is located in said cross brace.

31. A chair comprising:

a frame including armrests;

a seat supported on said frame;

a tiltable back movably supported on said frame and movable between upright and reclined positions; and

a back-supporting mechanism including a first and a second energy source operably connected to said back and said frame for producing a biasing force on said back to support a user as the user reclines between said upright and reclined positions, and further including a selecting mechanism for selectively varying the biasing force of at least one of said energy sources.

32. A chair as defined in claim 31 wherein at least one of said energy sources and said selecting mechanism are operably connected to and located on one of said armrests.

33. A chair as defined in claim 31 including a second selecting mechanism, said first and second selecting mechanisms being attached to said first and second energy sources, respectively.

34. A chair as defined in claim 31 including a shell having sections forming said seat and back.

35. A chair a defined in claim 31 wherein said back supporting mechanism includes a leaf spring operably connected to and supporting said seat and back.

36. A chair as defined in claim 31 wherein said first and second sources each include a resilient member, and said selecting mechanism includes an engagement plate operably connected to said resilient member and one of said back and armrests, said engagement plate being movable between at least two positions to selectively change the biasing force generated by said resilient member as said back is moved rearwardly.

37. A chair as defined in claim 36 wherein said at least two positions of said engagement plate includes a release position whereat said resilient members is released so that said resilient member does not generate a biasing force on said back as said back is moved rearwardly.

38. A chair as defined in claim 31 wherein said selecting mechanism is moveable to an enabling position whereat said at least one energy source generates said biasing force on said back when being reclined, and a disabling position whereat said at least one energy source does not generate any biasing force on said back when being reclined.