US20060138833A1

US20060138833A1 - Chair control for synchronized movement of chair seat and back, and chair having same

Info

Publication number: US20060138833A1
Application number: US11/025,094
Authority: US
Inventors: Kerry Brodrecht; Gerard Matern
Original assignee: Individual
Current assignee: Leggett and Platt Canada Co
Priority date: 2004-12-29
Filing date: 2004-12-29
Publication date: 2006-06-29
Also published as: CA2528422A1

Abstract

A chair seat adjustment mechanism has a support, a back bracket for attachment to a chair back and a seat plate for attachment to a chair seat. The back bracket is pivotally mounted to the support at a first pivot. The seat plate, which extends above the support, is pivotally mounted to the back bracket at a second pivot and slidably hinged to the support at a third pivot. The second pivot is positioned above and rearwardly of the first pivot. The third pivot is positioned forwardly of the second pivot such that rearward titling of the back bracket draws the seat plate rearwardly and tilts a rear of the seat plate downwardly. The third pivot may be a pivot pin on the support slidably received in an elongate slot on the seat plate, which may be slightly declined towards the back. A chair having such a chair seat adjustment mechanism is more comfortable for some users.

Description

FIELD OF THE INVENTION

The present invention relates to chair control mechanisms, particularly to chair seat adjustment mechanisms for synchronized movements of chair seat and chair back, and chairs having the same.

BACKGROUND

Office chairs often allow for titling of the chair back. It has been found that, for many users, it is more comfortable if the seat position is adjusted in synchronization with the back tilt. For example, there are office chairs where the seat tilts and/or shifts forwardly when the back is tilted rearwardly.
However, some users may find it uncomfortable if the seat tilts forwardly or shifts forwardly when the back is tilted. Further, some chair seat control mechanisms are relatively complex.
Therefore, there is a need for a simple chair control that allows synchronized movement of the chair seat and the chair back. There is also a need for a chair control that allows synchronized movement of the chair seat with the chair back, which may be more comfortable for users.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, there is provided a chair seat adjustment mechanism, comprising: a support; a back bracket for attachment to a chair back, said back bracket pivotally mounted to said support at a first pivot; a seat plate extending above said support, said seat plate for attachment to a chair seat, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot, said second pivot positioned above and rearwardly of said first pivot and said third pivot positioned forwardly of said second pivot such that rearward titling of said back bracket draws said seat plate rearwardly and tilts a rear of said seat plate downwardly.
In accordance with further aspect of the present invention, there is provided a chair comprising: a seat; a back; a support; a back bracket attached to said back, said back bracket pivotally mounted to said support at a first pivot; and a seat plate attached to said seat and extending above said support, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot, said second pivot positioned above and rearwardly of said first pivot and said third pivot positioned forwardly of said second pivot such that rearward titling of said back draws said seat rearwardly and tilts a rear of said seat downwardly.
In accordance with another aspect of the present invention, there is provided a chair seat adjustment mechanism, comprising: support means for supporting a chair seat and a chair back; first attachment means for attaching to said chair back, said first attachment means pivotally mounted to said support means at a first pivot means; and second attachment means for attaching to said chair seat, said second attachment means extending above said support means, said second attachment means pivotally mounted to said first attachment means at a second pivot means and slidably hinged to said support means at a third pivot means, said second pivot means positioned above and rearwardly of said first pivot means and said third pivot means positioned forwardly of said second pivot means such that rearward titling of said first attachment means draws said second attachment means rearwardly and tilts a rear of said second attachment means downwardly.
In accordance with yet another aspect of the present invention, there is provided a chair seat adjustment mechanism, comprising: a support; a back bracket for attachment to a chair back, said back bracket pivotally mounted to said support at a first pivot; a seat plate extending above said support, said seat plate for attachment to a chair seat, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot, said second pivot positioned above said first pivot and either forwardly or rearwardly of both of said first and third pivots such that rearward titling of said back bracket draws said seat plate rearwardly and tilts said seat plate rearwardly.
Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures illustrating example embodiments of the invention,
FIG. 1 is a side elevation of a chair having a chair control;
FIGS. 2A and 2B are side elevations of a portion of the chair of FIG. 1 showing the chair control in two different positions;
FIG. 3 is a perspective view of the chair control of FIG. 1 in isolation;
FIGS. 4A and 4B are side elevations of an isolated component of the chair control of FIGS. 2A and 2B;
FIG. 5 is a diagram illustrating an alternative arrangement of the pivots; and
FIG. 6 is a diagram illustrating a further alternative arrangement of the pivots.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary embodiment of an aspect of the invention is a chair 10 having a chair control 12, which joins a chair seat 14 and a chair back 16 to a chair post 18. The post 18 may be adjustable in height. The chair control 12 may be supported by a single post, such as illustrated in FIG. 1, or by multiple posts or another suitable form of support.
Referring to FIGS. 2A and 2B, the chair back 16 can be tilted between a forward position (FIG. 2A) and a backward position (FIG. 2B). The chair seat 14 moves in synchronization with the tilting of the chair back 16 so as to tilt and shift rearwardly when the chair back is titled rearwardly. The movements of the chair seat 14 are controlled by chair control 12.
Referring to FIG. 3, the chair control 12, which is an exemplary embodiment of the invention, has a support, such as main frame 20, mountable to the post 18 for supporting the chair seat 14 and the chair back 16, a seat plate 24 for attachment to the chair seat 14, and a back bracket 26 for attachment to the chair back 16. The main frame 20 may define a cavity 22, which may conveniently accommodate various components of the chair control mechanism. Each of the seat plate 14 and back bracket 16 can be a channel-shaped bracket. One or both the seat plate 14 and back bracket 16 may, however, have other suitable shapes.
The back bracket 26 is pivotally mounted at a pivot 28 to the main frame 20. The seat plate 24 extends above the main frame 20 and is pivotally mounted at a pivot 30 to the back bracket 26. The main frame 20 has a pivot pin 32 and the seat plate 24 has an elongate slot 34. The elongate slot 34 of the seat plate 24 slidably receives the pivot pin 32 so that the seat plate 24 is slidably hinged to the main frame 20 at the pivot 32. The slot 34 declines slightly from front to back. In an alternative embodiment, an elongate slot may be formed on the main frame 20 instead of the seat plate 24 and the seat plate may have a pivot pin received in the slot on the main frame so that the seat plate 24 is slidably hinged to the main frame 20 at the pivot pin. The seat plate 24 may also be otherwise slidably hinged at the pivot 32 to the main frame 20.
Each of the pivot pins 36, 38, 40 is separately formed and inserted into the openings in the corresponding component. Alternatively, the pins may be integrally formed on the corresponding components.
The pivot 30 is positioned above and rearwardly of the pivot 28, and the pivot 32 is positioned forwardly of the pivot 30, such that rearward tilting of the back bracket 26 draws the seat plate 24 rearwardly and tilts a rear of the seat plate 24 downwardly.
As is conventional, the back bracket 16 may be normally biased towards the forward position. For example, as illustrated in FIG. 3, the back bracket 26 may be biased by a coil spring 42 mounted in the cavity 22, which urges the back bracket to pivot forwardly.
As will be apparent from FIGS. 4A and 4B, pivotal movement of the back bracket 26 (FIG. 3) about the pivot 28 from a forward upright position to a backward titled position will cause the seat plate 24 to shift rearwardly, relative to the main frame 20, or pivot 28. The seat plate 24 is also caused to tilt backwardly. For example, when the back bracket 26 (FIG. 3) is tilted back from the position shown in FIG. 4A, it pivots clockwise about pivot 28 and draws pivot 30 downwardly and rearwardly in the direction of the arrow shown. As the pivot 30 moves downwardly and rearwardly, it draws the seat plate 24 rearwardly and the rear of the seat plate 24 at the pivot 30 downwardly. Since the seat plate 24 is slidably hinged at the pivot 32, it is able to shift rearwardly (in the direction indicated by the top arrow in FIG. 4B) as the slot 34 slides along the pivot 32. A rear of the seat plate 24 is also able to tilt downwardly as the seat plate 24 pivots about the pivot 32 in a clockwise direction (as indicated by the arrow adjacent the pivot 30 in FIG. 4B). Consequently, the seat plate 24 moves towards the position shown in FIG. 4B. Thus, rearward tilting of the back bracket 26 draws the seat plate 24 rearwardly and tilts the rear of the seat plate 24 downwardly. A reverse pivotal movement of the back bracket 26 will cause reverse movement of the seat plate 24.
Therefore, the chair control 12 provides a chair seat adjustment mechanism for adjusting the position of the chair seat 14 in response to the tilting of the chair back 16.
The chair control 12 may also have a locking mechanism (not shown) for selectively locking the back bracket 26 in one of a plurality of positions. Such locking mechanisms are known to persons skilled in the art.
In use, the seat 14 is attached to the seat plate 24 and the chair back 16 is attached to the back bracket 26. When the user tilts the back 16 and hence the back bracket 26 backwardly, the seat plate 24 and hence the chair seat 14 will shift and tilt rearwardly. When the chair back 16 and hence the back bracket 26 is titled forwardly, the seat plate 24 and hence the chair seat 14 will shift and tilt forwardly.
Thus, the chair 10 is comfortable to use for users who prefer such synchronized movement of the chair seat 14 and the chair back 16.
In contrast, if the pivots 28, 30 and 32 are arranged such that the pivot 30 is between the pivots 28 and 32, a pivotal movement of the back bracket 26 would cause a tilting of the seat plate 24 in the opposite direction. That is, when the back bracket 26 pivots backwardly, the seat plate 24 shifts rearwardly but pivots forwardly, and when the back bracket 26 pivots forwardly, the seat plate 24 shifts forwardly but pivots backwardly.
Another advantage of the chair control 12 is that the distance between pivots 30 and 32, or pivot 28 and the chair back 16, may be maximized for a given overall size of the chair control 12, if so desired. Thus, the chair control 12 can have a compact size with good functionality and durability. For example, a longer distance between the pivots may reduce the torque required to actuate the control, and thus the stress on the components.
The chair control 12 is also simple in construction. It only requires two moving components to function, namely the seat plate and the back bracket.
As now can be appreciated, it is possible to alter the movement of the chair seat 14 in response to the titling of the chair back 16 by adjusting relative positions of the pivots 28, 30 and 32. Alternatively, it is possible to alter the degree of tilt of the seat by adjusting the shape and orientation of the slot 34. For example, a steep decline of the slot 34 may reduce the amount of tilting of the seat 14 when the back 16 is tilted. As will be understood by a person skilled in the art, when the slot 34 declines from front to back, the amount of tilting of the seat plate 24 is reduced because the vertical distance between pivots 30 and 32 changes less when the back bracket 26 is pivoted about pivot 28, compared with a leveled slot. Further, the slot 34 may be curved so that pivot 32 can follow more closely the arcuate movement of the pivot 30 so as to reduce or eliminate tilting of the seat plate 24 caused by the pivotal movement of the back bracket 26. When the slot declines from back to front, the amount of titling of the seat plate 24 is increased in comparison to a leveled slot.
Further, when the pivot 30 is nearly directly above the pivot 28, titling of the back bracket 26 causes more horizontal shift than downward tilt of the seat plate 24. In contrast, when the pivot 30 is rearwardly remote from the pivot 28, titling of the back bracket 26 causes more downward tilt than horizontal shift of the seat plate 24.
As can be understood by one of skill in the art, in an alternative embodiment the pivot 32 may be positioned between the pivots 28 and 32 as shown in FIG. 5. In such an arrangement, rearward tilting of the back bracket 26 also draws the seat plate 24 rearwardly and tilts the rear of the seat plate 24 downwardly.
The pivots may also be positioned as shown in FIG. 6. In this case, the pivot 30 is positioned above the pivot 28 and forwardly of both of the pivots 28 and 32. The relative positions of the pivots 28 and 30 may vary, as discussed above. As can be appreciated, under this arrangement, rearward tilting of the back bracket again draws the seat plate rearwardly but tilts the front of the seat plate upwardly. However, since the pivots 28 and 32 are on the same side of the pivot 30, the seat plate is again tilted clockwise. Some users may prefer this kind of seat movement when the back is tilted backwardly.
In the exemplary embodiments described above and illustrated in the figures, the seat plate 24 and the back bracket 26 are both channel-shaped and are nested with each other and the main frame 20. While channel-shaped brackets are advantageous as the control assembly can be made compact and to accommodate other components while maintaining good physical strength, the seat plate or the back bracket may be otherwise shaped.
The chair control 12 may incorporate any other suitable components or control mechanisms for adjusting the chair height, chair seat, or chair back. For example, the chair control 12 may include handles for adjusting or locking any of the components of the chair, biasing members for biasing a part of the control, actuators for actuating an adjustment such as a gas cylinder actuator, and the like.
Other features, benefits and advantages of the present invention can be understood from this description and the drawings by those skilled in the art.
Of course, the above described embodiments are intended to be illustrative only and in no way limiting. The described embodiments are susceptible to many modifications of form, arrangement of parts, details and order of operation. The invention, rather, is intended to encompass all such modification within its scope, as defined by the claims.

Claims

1. A chair seat adjustment mechanism, comprising:

a support;

a back bracket for attachment to a chair back, said back bracket pivotally mounted to said support at a first pivot;

a seat plate extending above said support, said seat plate for attachment to a chair seat, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot,

said second pivot positioned above and rearwardly of said first pivot and said third pivot positioned forwardly of said second pivot such that rearward titling of said back bracket draws said seat plate rearwardly and tilts a rear of said seat plate downwardly.

2. The mechanism of claim 1, wherein one of said seat plate and said support defines an elongate slot, and wherein said third pivot comprises a pivot pin on the other of said seat plate and said support slidably received in said slot, such that said seat plate is slidably hinged at said pivot pin.

3. The mechanism of claim 2, wherein said slot is shaped and oriented to allow reciprocal movement of said seat plate when said back bracket is pivoted about said first pivot.

4. The mechanism of claim 1, wherein said back bracket is normally biased towards a forward position.

5. The mechanism of claim 1, wherein at least one of said seat plate and said back bracket is generally channel-shaped and is nested with said support.

6. A chair comprising:

a seat;

a back;

a support;

a back bracket attached to said back, said back bracket pivotally mounted to said support at a first pivot; and

a seat plate attached to said seat and extending above said support, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot,

said second pivot positioned above and rearwardly of said first pivot and said third pivot positioned forwardly of said second pivot such that rearward titling of said back draws said seat rearwardly and tilts a rear of said seat downwardly.

7. The chair of claim 6, wherein one of said seat plate and said support defines an elongate slot, and wherein said third pivot comprises a pivot pin on the other of said seat plate and said support slidably received in said slot, such that said seat plate is slidably hinged at said pivot pin.

8. The chair of claim 7, wherein said slot is shaped and oriented to allow reciprocal movement of said seat plate when said back bracket is pivoted about said first pivot.

9. The chair of claim 8, wherein said back bracket is normally biased towards a forward position.

10. The chair of claim 6, wherein at least one of said seat plate and said back bracket is generally channel-shaped and is nested with said support.

11. A chair seat adjustment mechanism, comprising:

support means for supporting a chair seat and a chair back;

first attachment means for attaching to said chair back, said first attachment means pivotally mounted to said support means at a first pivot means; and

second attachment means for attaching to said chair seat, said second attachment means extending above said support means, said second attachment means pivotally mounted to said first attachment means at a second pivot means and slidably hinged to said support means at a third pivot means,

said second pivot means positioned above and rearwardly of said first pivot means and said third pivot means positioned forwardly of said second pivot means such that rearward titling of said first attachment means draws said second attachment means rearwardly and tilts a rear of said second attachment means downwardly.

12. A chair seat adjustment mechanism, comprising:

a support;

said second pivot positioned above said first pivot and either forwardly or rearwardly of both of said first and third pivots such that rearward titling of said back bracket draws said seat plate rearwardly and tilts said seat plate rearwardly.