Patent Application
20060097554
1. Field of the Invention
The present invention relates to chairs, and in particular, to a backrest assembly for a task chair, the backrest assembly including a backrest depth adjustment mechanism.
2. Description of the Related Art
Task chairs are commonly used by persons while working in a seated position in an office or other occupational environment. Typically, such chairs include a base assembly with caster wheels for rolling movement over a floor surface, a pneumatic cylinder connecting the base assembly to the seat assembly for vertical adjustment, as well as a number of manual adjustment features to allow the user to adjust the position and/or movement characteristics of the chair to a desired configuration.
Many known task chairs include a seat depth adjustment feature, wherein the seat is adjustable in a front-to-back manner with respect to the seat support structure in order to accommodate differently sized users. A disadvantage of this arrangement is that seat depth adjustment mechanisms are often mechanically complex and usually must be integrated with a tilt control mechanism which is located beneath the seat. The integration of the seat depth adjustment mechanism with the tilt control mechanism tends to increase manufacturing difficulties and the overall cost of the chair. Further, the user must reach beneath the chair seat to actuate the seat depth adjustment mechanism.
The present invention provides a backrest depth adjustment mechanism which allows adjustment of the backrest assembly in a front-to-back manner with respect to the seat. The backrest assembly generally includes a backrest frame supporting the backrest. The backrest frame includes opposite end portions, and at least one of the end portions includes a backrest depth adjustment mechanism. The backrest depth adjustment mechanism includes a stationary portion and a movable portion, wherein the movable portion is movable with respect to the stationary portion. An actuator mechanism allows the user to actuate the backrest depth adjustment mechanism to move the backrest to a desired depth position.
A pin is slidably received within a hole in the stationary portion, and is biased outwardly thereof by a pin spring. A slide member is slidably mounted within a recess of the movable portion and includes a cam surface. An actuator cable controls the position of the slide member. A main spring includes one end connected by an anchor pin to the stationary portion, and an opposite end connected to the movable portion. The pin spring normally biases the pin into engagement with one of the holes in the movable portion to fix the location of the movable portion with respect to the stationary portion, and in turn, the depth position of the backrest. When a user desires to move the backrest in a forward or rearward direction, the user may utilize an actuator mechanism which controls the actuator cable.
When the user desires to move the backrest in a rearward direction, the user actuates the backrest depth adjustment mechanism and places a force against the backrest in a rearward direction, such as by the user leaning back against the backrest. Once the user has reached a desired position, the user releases the actuator mechanism and the backrest will lock into a fixed position. When the user desires to move the backrest in a forward direction, the user actuates the backrest depth adjustment mechanism and removes force from the backrest, such as by the user leaning forward with respect to the backrest, thereby allowing the backrest adjustment mechanism to move the backrest forward via action of the spring which connects the stationary portion to the movable portion of the backrest depth adjustment mechanism. Again, once the user has reached a desired position, the user releases the actuator mechanism and the backrest will lock into a fixed position.
In one form thereof, the present invention provides a chair, including seat support structure; a seat assembly supported by the seat support structure; a backrest assembly, including a generally U-shaped member having a pair of end portions; a backrest supported by the U-shaped member; and a backrest depth adjustment mechanism connecting at least one of the end portions to the seat support structure for generally rectilinear relative movement between the U-shaped member and the seat support structure, the depth adjustment mechanism including a selectively actuable backrest depth position lock mechanism connected between the U-shaped member and the seat support structure.
In another form thereof, the present invention provides a chair, including seat support structure; a seat assembly supported by the seat support structure, the seat assembly including a pair of upwardly-extending side portions; a backrest assembly, including a generally U-shaped member having a pair of end portions pivotally connected to respective the side portions of the seat assembly; a backrest supported by the U-shaped member; and a backrest depth adjustment mechanism associated with at least one of the end portions of the U-shaped member for generally rectilinear relative movement between the U-shaped member and the seat support structure, the backrest depth adjustment mechanism including a selectively actuable backrest depth position lock mechanism connected between the U-shaped member and the seat support structure.
In yet another form thereof, the present invention provides a chair, including seat support structure; a seat assembly supported by the seat support structure; a backrest assembly, including a generally U-shaped member having a pair of end portions, and a backrest supported by the U-shaped member; and a backrest depth adjustment mechanism connecting at least one of the end portions to the seat support structure for generally rectilinear relative movement between the U-shaped member and the seat support structure, the depth adjustment mechanism including a stationary portion connected to one of the end portions and the seat support structure; a movable portion connected to the other of the end portions and the seat support structure, the movable portion selectively movable with respect to the stationary portion whereby a backrest depth position of the U-shaped member and the backrest may be adjusted with respect to the seat assembly; and a selectively actuable backrest depth position lock mechanism connected between the U-shaped member and the seat support structure.
In yet a further form thereof, the present invention provides a chair, including seat support structure; a seat assembly supported by the seat support structure; a backrest assembly, including a frame member; a backrest supported by the frame member; and a backrest depth adjustment mechanism connecting the frame member to the seat support structure for generally rectilinear relative movement between the frame member and the seat support structure, the depth adjustment mechanism including a selectively actuable backrest depth position lock mechanism connected between the frame member and the seat support structure.
In yet a further form thereof, the present invention provides a chair, including seat support structure; a seat assembly supported by the seat support structure; a backrest assembly, including a frame member; a backrest supported by the frame member; and a backrest depth adjustment mechanism connecting the frame member to the seat support structure and including means for selectively adjusting a backrest depth position of the frame member and the backrest with respect to the seat assembly.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
Referring to
Yoke member 14 generally includes transverse beam 30 and a pair of upwardly-extending side portions 32 at opposite ends of transverse beam 30. The upper end of pneumatic cylinder 28 is mounted to transverse beam 30 in a suitable manner, such as by welding or by a press-fit engagement, for example. Although shown in the context of a task chair which includes seat support structure or base assembly 12 having chair base 20 with a plurality of arms 22 projecting from hub 24, the backrest depth adjustment mechanism described herein is equally applicable to a side chair having a seat support structure which includes three or four fixed legs, for example.
Referring now to
Backrest 38 may include a flexible elastomeric structural material having one or more rigid members embedded therein, which provide connection points for securing backrest 38 to backrest frame 34, and which allows backrest 38 to flexibly conform to the movement of a seated user, as discussed in detail in U.S. Patent Application Publication No. US 2003/0127896 A1, application Ser. No. 10/315,838, entitled CHAIR WITH LUMBAR SUPPORT AND CONFORMING BACK, filed on Dec. 10, 2002, and U.S. patent application Ser. No. 10/887,362, entitled CHAIR WITH LUMBAR SUPPORT AND CONFORMING BACK, filed on Jul. 8, 2004 (Attorney Docket Ref.: KIM0496-03), each assigned to the assignee of the present invention, the disclosures of which are expressly incorporated herein by reference. Backrest 38 may also optionally include a cushion (not shown) attached thereto.
Seat assembly 16 is discussed in detail in U.S. Patent Application Publication No. US 2003/0137171 A1, application Ser. No. 10/315,590, entitled CHAIR WITH CONFORMING SEAT, filed on Dec. 10, 2002, assigned to the assignee of the present invention, the disclosure of which is expressly incorporated herein by reference. A ride mechanism by which seat assembly 16 and backrest assembly 18 are connected for synchronous movement is discussed in detail in U.S. patent application Ser. No. 10/915,882, entitled CHAIR RIDE MECHANISM WITH TENSION ASSEMBLY, filed on Aug. 11, 2004 (Attorney Docket Ref.: KIM0628-01), assigned to the assignee of the present invention, the disclosure of which is expressly incorporated herein by reference.
Referring now to
Slide member 50 is slidably mounted within recess 41 of movable portion 40 and includes cam surface 54. Actuator cable 56 includes end 57 received within holder 51 of slide member 50, and is translated to control the position of slide member 50 as described below. A user-controlled actuator mechanism (not shown) is operable to translate actuator cable 56, and may be configured as an actuation lever, a rotating wheel, or a pushbutton mechanism, for example. The actuator mechanism may be accessed on, or extend through, an exterior surface of an end portion 36 of backrest frame 34, for example. Main spring 58 includes one end connected by anchor pin 60 to stationary portion 42, and an opposite end connected by pin 59 to movable portion 40. Main spring 58 normally biases movable portion 40 toward or into stationary portion 42.
Referring now to
A user releases the actuator mechanism once the user has moved backrest 38 to a desired backrest position. Upon release of the actuator mechanism, pin spring 48 biases pin 46 toward cam surface 54 of slide member 50. Since the actuator mechanism is no longer applying force against the bias of pin spring 48, groove 45 of pin 46 engages and forces cam surface 54 of slide member 50 to move in a direction opposite of the direction indicated by Arrow A in
Referring now to
A user releases the actuator mechanism once the user has moved backrest 38 to a desired backrest position. Upon release of the actuator mechanism, pin spring 48 biases pin 46 toward cam surface 54 of slide member 50. Since the actuator mechanism is no longer applying force against the bias of pin spring 48, groove 45 of pin 46 forces cam surface 54 of slide member 50 to move in a direction opposite of the direction indicated by Arrow A in
In this manner, the user may selectively adjust the depth of backrest 38 for generally rectilinear relative movement between backrest frame 34 and seat support structure 12, as opposed to adjusting the seat in a front-to-back manner as in the seat depth adjustment mechanisms of prior chairs. The selective depth adjustment of backrest 38 of the present invention provides the advantage of removing mechanically complex adjustment mechanisms from beneath the seat, thereby decreasing manufacturing difficulties of the mechanism and increasing the ease of use of the mechanism by a user of the chair.
Although the description above details the operation and structure of only one backrest depth adjustment mechanism 39, an identical mechanism may be located within opposite end portion 36 on the opposite side of task chair 10 wherein, in operation, both of the mechanisms could work in tandem with simultaneous actuation. In the alternative, one end portion 36 of backrest frame 34 may include a backrest depth adjustment mechanism, and the opposite end portion 36 may include a simplified follower mechanism including only stationary portion 42, movable portion 40, and main spring 58 without any other components, thereby reducing the amount of total components of the assembly.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
