Chair control device
A mechanism is provided for an office chair to adjust the tilt of the seat portion relative to the base of the chair. The mechanism includes an adjustable member tiltably mounted on a base, a compression spring bearing on the adjustable member and connected to the base using a retaining bolt running through the center of the compression spring, and a clutch device fixably attached to the base extending to the adjustable member, which clutch device is capable of holding the adjustable member in a fixed position relative to the base.
The present invention relates to an adjustment mechanism for a chair allowing relative displacement of two chair parts. In an exemplary embodiment, the invention provides a seat tilt and locking device.
BACKGROUNDIt is typical in office chairs for the seat to tilt rearwardly as an occupant leans back in the seat. To accommodate this motion, known chair control devices allow a seat portion of a chair to tilt in relation to its wheeled support. These chair control devices are provided with an adjustable spring to counteract the rearward force exerted on the chair by the user, which force will ordinarily cause the chair to return to an upright position when unoccupied. This adjustable spring may be pretensioned by a user to a greater or lesser degree to cause the spring to exert a greater or lesser reaction force to the rearward force supplied by the user.
Sophisticated chair control devices are known which, in addition to having an adjustable spring, incorporate a clutch assembly which allows a user to lock the chair in any reclined or upright position throughout its range of motion. Simpler devices are also known which have a tilt lock mechanism which merely prevents the chair from righting itself when in a reclined position and/or locks the chair in an upright position.
The more sophisticated chair control devices which incorporate the clutch assembly feature are far more expensive and complicated to manufacture than the simpler tilt lock mechanisms. This is due to certain design considerations, because of which it has been necessary in the past to use an expensive tilt assembly and torsion spring in devices featuring both an adjustable pretensioned spring for counteracting the tilt force exerted by a user and a clutch assembly for locking in a tilt position.
SUMMARY OF THE INVENTIONIn an exemplary embodiment, an adjustment mechanism for a chair comprises a base, an adjustable member tiltably mounted on the base and moveable between a first position and a second position, a compression spring bearing on the adjustable member which urges the adjustable member toward the first position when compressed and a clutch attached to the base and the adjustable member capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
In another embodiment, an adjustment mechanism for a chair comprises a base, an adjustable member tiltably mounted on the base and moveable between a first position and a second position, an elastic element bearing on the adjustable member which urges the adjustable member toward the first position when deformed, and a clutch comprising a clutch lever mounted on the base and a clutch assembly attached to the adjustable member. The clutch assembly connects the clutch lever and the adjustable member, and the clutch is capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
In yet another embodiment, an adjustment mechanism for a chair comprises a base comprising a first central plate and a first pair of sidewalls extending substantially perpendicularly downward from the first central plate, the first pair of sidewalls being substantially parallel to one another, an adjustable member tiltably mounted on the base below the first central plate moveable between a first position and a second position, an elastic element provided below the adjustable member and the first central plate of the base which bears on the adjustable member and urges the adjustable member toward the first position when deformed, and a clutch attached to the base and the adjustable member capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
In yet another embodiment, an adjustment mechanism for a chair comprises a base comprising a first central plate and a first pair of sidewalls extending substantially perpendicularly downward from the first central plate, the first pair of sidewalls being substantially parallel to one another, an adjustable member moveable between a first position and a second position which is tiltably mounted on the base, and which comprises a second central plate, a column mount and a second pair of sidewalls extending substantially perpendicularly downward from the second central plate to the column mount, the second pair of sidewalls being substantially parallel to one another, an elastic element bearing on the adjustable member which urges the adjustable member toward the first position when deformed, and a clutch attached to the base and the adjustable member capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
BRIEF DESCRIPTION OF THE DRAWINGS
Before any embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangements of components set forth in the following description, or illustrated in the drawings. The invention is capable of alternative embodiments and of being practiced or being carried out in various ways. Specifically, numerical dimensions, where they appear on the following drawings, represent those of exemplary embodiments only and may be modified by one skilled in the art as conditions warrant. Also, it is to be understood that the terminology used herein is for the purpose of illustrative description and should not be regarded as limiting.
DETAILED DESCRIPTION
Counteracting the tendency of the tilt mechanism 10 to rotate relative to the base 11 is the compression spring 13 compressed between the underside of the tilt mechanism 10 and a knob 12 secured to the base 11 by the retaining bolt 14. The knob 12 is adjustably mounted on the retaining bolt 14 so that it may be rotated to add or remove a preloading force to the compression spring 13. This preloading force causes the tilt mechanism 10 to rotate more or less stiffly relative to the base 11 when subjected to an outside force. Through this mechanism, a user of the chair can adjust the recline resistance of her chair to her personal comfort.
In the conventional mechanism shown in
Because the tilt mechanism 30 is provided with these sidewalls 37 extending from the central plate 38 away from the base 31 towards the bottom of the device in contrast to the tilt mechanisms of the prior art, the surface of the central plate 38 on which a spring bears can be closer to the base 31 than would otherwise be the case. As such, a compression spring can be used rather than torsion spring of the prior art. To further accommodate this substitution, the clutch assembly 36 and a clutch lever (not shown) can be provided as a unit fixably mounted on the base 31 below which point it pivotably engages the tilt mechanism 30. A knob 32 is also provided secured to the base 31 by the retaining bolt 34. The knob 32 is adjustably mounted on the retaining bolt 34 so that it may be rotated to add or remove a preloading force to the compression spring 33.
The tilt mechanism supports the column mount 55 which can be mounted on the column of a standard wheeled support for an office chair (not shown). This column may include a gas cylinder having two-chambers separated by a normally closed valve. A user actuator 62 may be provided tiltably mounted in a housing above the valve opening member, and which may be operated to depress the valve opening member in order to open the cylinder valve to permit height adjustment of the seat.
Further adjustment devices may be provided as part of the present chair control device including a primary clutch lever 63 attached to the base 51 by a clutch housing 43. The primary clutch lever 63 is provided to operate a clutch assembly at least partially concealed within the shroud 44, which assembly comprises at least one clutch plate and a clutch pin 41. The primary clutch lever 63 may be operated to engage or disengage the clutch assembly to prevent or permit tilt mechanism to move relative to the base 51. A secondary adjustment assembly 60 may be provided to support element for a chair backrest, the motion of which secondary adjustment assembly 60 may halted by the engagement of a secondary clutch lever 61. A recline locking lever 65 may be provided mounted on the base 51 having a recline locking stop 66 thereon which may be slid into a blocking position to prevent the tilt assembly from being adjusted to the fully upright position relative to the base 51.
Claims
1. An adjustment mechanism for a chair, the mechanism comprising:
- a base;
- an adjustable member tiltably mounted on the base and moveable between a first position and a second position;
- a compression spring bearing on the adjustable member which urges the adjustable member toward the first position when compressed; and
- a clutch attached to the base and the adjustable member capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
2. The adjustment mechanism of claim 1, further comprising a manual adjustment device bearing on the compression spring and a retaining member passing thorough the compression spring,
- wherein the retaining member is held in tension between the manual adjustment device and the base.
3. The adjustment mechanism of claim 1, wherein the base comprises a central plate and a pair of sidewalls extending substantially perpendicularly downward from the central plate, the pair of sidewalls being substantially parallel to one another.
4. The adjustment mechanism chair of claim 3, further comprising a shroud attached to the base below the adjustable member,
- wherein the shroud at least partially covers the adjustable member to reduce the risk to a user of a user's finger being caught between the adjustable member and the base.
5. The adjustment mechanism chair of claim 1, further comprising a slider having an abutment thereon mounted on the base which may be slid into a blocking position to prevent the adjustable member from reaching the first position.
6. The adjustment mechanism of claim 3, further comprising a seat connected above and to the base and a support connected below and to the adjustable member,
- wherein moving the adjustable member to the first position causes the seat to assume an upright position relative to the support, and
- wherein moving the adjustable member to the second position causes the seat to assume a reclined position relative to the support.
7. An adjustment mechanism for a chair, the mechanism comprising:
- a base;
- an adjustable member tiltably mounted on the base and moveable between a first position and a second position;
- an elastic element bearing on the adjustable member which urges the adjustable member toward the first position when deformed; and
- a clutch comprising a clutch lever mounted on the base and a clutch assembly attached to the adjustable member,
- wherein the clutch assembly connects the clutch lever and the adjustable member, and
- wherein the clutch is capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
8. The adjustment mechanism of claim 7, wherein the elastic element is a compression spring.
9. The adjustment mechanism of claim 8, further comprising a manual adjustment device bearing on the compression spring and a retaining member passing thorough the compression spring,
- wherein the retaining member is held in tension between the manual adjustment device and the base.
10. The adjustment mechanism of claim 7, wherein the clutch lever is tiltably mounted on the base and may be operated to disengage a spring loaded bracket.
11. The adjustment mechanism chair of claim 7, further comprising a slider having an abutment thereon mounted on the base which may be slid into a blocking position to prevent the adjustable member from reaching the first position.
12. The adjustment mechanism of claim 7, wherein the base comprises a central plate and a pair of sidewalls extending substantially perpendicularly downward from the central plate, the pair of sidewalls being substantially parallel to one another.
13. The adjustment mechanism chair of claim 12, further comprising a shroud attached to the base below the adjustable member,
- wherein the shroud at least partially covers the adjustable member to reduce the risk to a user of a user's finger being caught between the adjustable member and the base.
14. The adjustment mechanism of claim 12, further comprising a seat connected above and to the base and a support connected below and to the adjustable member,
- wherein moving the adjustable member to the first position causes the seat to assume an upright position relative to the support, and
- wherein moving the adjustable member to the second position causes the seat to assume a reclined position relative to the support.
15. The adjustment mechanism of claim 7, wherein the clutch assembly comprises at least one clutch plate and a clutch pin, and
- wherein when the clutch lever is operated to disengage a spring loaded bracket, the at least one clutch plate is released to move relative to the clutch pin which in turn releases the clutch assembly to move relative to the base.
16. The adjustment mechanism of claim 15, wherein the clutch assembly is attached to the adjustable member at a pivot point lying between the clutch pin and the central plate of the base.
17. The adjustment mechanism of claim 16, wherein the pivot point is provided below the central plate of the base and above the pivot pin of the clutch assembly.
18. An adjustment mechanism for a chair, the mechanism comprising:
- a base comprising a first central plate and a first pair of sidewalls extending substantially perpendicularly downward from the first central plate, the first pair of sidewalls being substantially parallel to one another;
- an adjustable member tiltably mounted on the base below the first central plate moveable between a first position and a second position;
- an elastic element provided below the adjustable member and the first central plate of the base which bears on the adjustable member and urges the adjustable member toward the first position when deformed; and
- a clutch attached to the base and the adjustable member capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
19. The adjustment mechanism of claim 18, wherein the elastic element is a compression spring.
20. The adjustment mechanism of claim 19, further comprising a manual adjustment device bearing on the compression spring and a retaining member passing thorough the compression spring,
- wherein the retaining member is held in tension between the manual adjustment device and the base.
21. The adjustment mechanism chair of claim 18, further comprising a shroud attached to the base below the adjustable member,
- wherein the shroud at least partially covers the adjustable member to reduce the risk to a user of a user's finger being caught between the adjustable member and the base.
22. The adjustment mechanism chair of claim 18, further comprising a slider having an abutment thereon mounted on the base which may be slid into a blocking position to prevent the adjustable member from reaching the first position.
23. The adjustment mechanism of claim 18, further comprising a seat connected above and to the base and a support connected below and to the adjustable member,
- wherein moving the adjustable member to the first position causes the seat to assume an upright position relative to the support, and
- wherein moving the adjustable member to the second position causes the seat to assume a reclined position relative to the support.
24. An adjustment mechanism for a chair, the mechanism comprising:
- a base comprising a first central plate and a first pair of sidewalls extending substantially perpendicularly downward from the first central plate, the first pair of sidewalls being substantially parallel to one another;
- an adjustable member moveable between a first position and a second position which is tiltably mounted on the base, and which comprises a second central plate, a column mount and a second pair of sidewalls extending substantially perpendicularly downward from the second central plate to the column mount, the second pair of sidewalls being substantially parallel to one another;
- an elastic element bearing on the adjustable member which urges the adjustable member toward the first position when deformed; and
- a clutch attached to the base and the adjustable member capable of engaging to hold the adjustable member in a fixed position relative to the base between or including the first position and the second position.
25. The adjustment mechanism of claim 24, wherein a passage is provided through the adjustable member defined by the column support, the first pair of sidewalls and the second central plate.
26. The adjustment mechanism of claim 24, wherein the adjustable member further comprises reinforcing flanges extending downward from the second central plate to reinforce the second central plate.
27. The adjustment mechanism of claim 24, wherein the elastic element is a compression spring.
28. The adjustment mechanism of claim 27, further comprising a manual adjustment device bearing on the compression spring and a retaining member passing thorough the compression spring,
- wherein the retaining member is held in tension between the manual adjustment device and the base.
29. The adjustment mechanism chair of claim 24, further comprising a shroud attached to the base below the adjustable member,
- wherein the shroud at least partially covers the adjustable member to reduce the risk to a user of a user's finger being caught between the adjustable member and the base.
30. The adjustment mechanism chair of claim 24, further comprising a slider having an abutment thereon mounted on the base which may be slid into a blocking position to prevent the adjustable member from reaching the first position.
31. The adjustment mechanism of claim 24, further comprising a seat connected above and to the base and a support connected below and to the adjustable member,
- wherein moving the adjustable member to the first position causes the seat to assume an upright position relative to the support, and
- wherein moving the adjustable member to the second position causes the seat to assume a reclined position relative to the support.
Type: Application
Filed: Mar 17, 2005
Publication Date: Oct 5, 2006
Inventor: Ing Kwa (Monrovia, CA)
Application Number: 11/083,436
International Classification: A47C 1/027 (20060101);