HK1097167B - Chair with adjustable seat depth - Google Patents

Description

Chair with adjustable seat depth

Cross reference to related applications

This patent application is related to the following patent applications: "seat with rearward and forward passive tilt capability", application No. 10/749,008, attorney docket No. 087522-; "horizontally adjustable seat arm", application No. 10/748,537, attorney docket No. 087522 and 785 and 329; "seat back with improved resilience and support", application No. 10/750,576, attorney docket No. 087522 and 785 and 336; "Vertically adjustable arm rest", application No. 10/749,010, attorney docket No. 087522 & 785 & 347; and "seat with tilt lock", application No. 10/749,009, attorney docket No. 087522 and 785 and 350; the above applications were all filed on 30/12/2003 and are incorporated herein by reference in their entirety.

Background

The present invention relates to office chairs in which the position of the seat is adjustable in a forward and rearward direction relative to the back of the chair to accommodate users of different heights. More particularly, the present invention relates to office chairs in which the position of the seat is adjustable in a forward and rearward direction relative to the back of the chair, and in which the means for such forward and rearward adjustment does not increase the height of the seat relative to the ground.

Office chairs typically include a base, a seat, and a backrest. The office chair is mass produced but must be comfortable for users of all heights and weights. This is difficult to achieve because the size of each component of such office chairs must be fixed. One prior solution to this problem has been to provide a backrest that is adjustable in a vertical direction so that the backrest can be adjusted upwardly to accommodate taller users and downwardly to accommodate shorter users. In this manner, each user can adjust the seat back for optimal lumbar support. Another important parameter determining the comfort of an office chair is adequate leg support, which is determined by the depth of the seat portion. A seat with a longer depth provides good leg support for a taller user with longer legs. However, for a shorter user, the longer seat depth will cause the user's back to be too far from the backrest, causing the shorter user to fall back when his/her back is against the backrest. For a shorter user, a seat having a suitable depth of longitudinal dimension can allow the user's back to be attached to the backrest when the shorter user is in a suitable upright position with both feet lying flat on the floor. However, for taller users, such seats provide inadequate support for the user's legs, resulting in fatigue and discomfort.

It is an object of the present invention to provide a chair wherein the position of the seat is adjustable in the longitudinal direction, i.e. forward and backward, as desired by the user.

It is another object of the present invention to provide a chair wherein the position of the seat can be adjusted in the longitudinal direction while the user is seated on the chair.

It is a further object of the present invention to provide a chair wherein the seat position can be adjusted by the user in the longitudinal direction and wherein the adjustment means does not significantly increase the height of the seat above the ground.

Disclosure of Invention

In one aspect of the invention, a seat includes a base; a seat plate supported above the base; a seat pan slidably mounted on the seat plate so as to be longitudinally slidable; and a longitudinal operating means for sliding the seat pan longitudinally relative to the seat plate. The user can move the longitudinal operating means in the longitudinal direction to operate the sliding of the seat pan relative to the seat plate.

In another aspect of the invention, the seat comprises means for locking the seat pan in a fixed longitudinal position relative to said seat pan. When the user uses the longitudinal operating means, the locking means is disengaged, allowing the seat pan to slide freely in the longitudinal direction relative to the seat plate. When the user disengages the longitudinal operating means, the locking means engages to prevent the seat pan from sliding relative to the seat plate.

In a preferred embodiment, an office chair comprises a base, a seat plate mounted on the base, a seat pan slidably mounted on the seat plate such that the seat pan can slide forward and backward relative to the seat plate, and a locking device for securing the seat pan to the seat plate at a user-selected position. The operating device includes a movable arm that slides within a longitudinal guide channel formed in the seat pan. The lock engagement means comprises one or more locking pins disposed in the guide channel and extending through holes in the guide channel to engage any one of a plurality of notches in the fixed seat plate. Operation of the activating arm causes the locking pin to retract from the seat plate notch so that the seat pan can slide forward or backward on the seat plate as desired by the user. When the activating arm is released, the locking pin again extends outwardly through the hole in the guide channel to engage a different notch in the seat plate, thereby securing the seat pan in a desired position relative to the seat plate.

The seat depth adjustment apparatus of the present invention is a simple, low cost device that is easy to operate with one hand. The device also has a low vertical profile so that it does not significantly increase the height of the seat pan relative to the floor on which the seat is placed. The seat depth adjustment is integrally provided in the chair and need not be installed as an additional part, which requires labor and materials. The seat depth adjustment mechanism allows users of different heights and proportions to feel the office chair more comfortable.

Drawings

The invention will be more readily understood by means of the drawings of a preferred embodiment, in which

FIG. 1 is a bottom perspective view of an office chair having a seat depth adjustment mechanism of the present invention;

FIG. 2 is a top exploded view of the chair plate with seat depth adjustment activating arms;

FIG. 3 is a bottom exploded view of the chair plate with seat depth adjustment activating arms;

FIG. 4 is an exploded view of the seat pan and seat plate with the activating arm mounted above the locking pin;

FIG. 5 is a bottom plan view of the seat pan with the seat depth adjustment activation arm in the retracted, locked position;

FIG. 6 is a bottom plan view of the seat pan with the seat depth adjustment activation arm in the extended unlocked position;

FIG. 7 is a top view of the seat pan with the locking pin without the moveable arm;

FIG. 8 is a top view of the seat pan with the seat depth adjustment activating arm mounted above the locking pin; and

fig. 9 is a bottom view of the seat depth adjustment activating arm acting on the locking pin.

Detailed Description

According to the present invention, a chair 10, such as an office chair, includes a base member 14 positioned on a base 12. Supported above the base 14 is a seat frame 16 that includes a seat plate 18. Seat pan 20 is slidably mounted to seat plate 18, i.e., seat pan 20 is movable longitudinally, i.e., in a fore-aft direction, relative to seat plate 18. Although in some embodiments of office chairs having the seat depth mechanism of the present invention, seat plate 18 can tilt forward or backward in response to movement by the user, the seat plate is longitudinally fixed relative to base 14. This optional forward and backward tilting is independent of the forward and backward sliding of the seat pan relative to the seat plate, which is the subject of the present invention.

As shown in fig. 2 and 3, the sliding movement of seat pan 20 relative to seat plate 18 is controlled by a longitudinal operating means for sliding seat pan 18 in the longitudinal direction, which includes a movable arm 24. Formed in seat pan 20 is a means for receiving the moveable arm that includes a longitudinal guide channel 22 that extends downwardly below the lower surface of seat pan 20. A moveable arm 24 is slidably disposed within the longitudinal guide channel 22. At the forward end of the arm 24 is a handle 26. Handle 26 extends from channel 22 near the front end of seat pan 20 and is designed to be easily accessible by a user seated in seat 10.

As shown in fig. 2 and 7, the longitudinal guide channel 22 comprises two longitudinal side walls 23 and a bottom wall 25. Bottom wall 25 of longitudinal guide channel 22 includes a front opening 28 through which activating arm 24 may slide. Two inwardly extending guide taps 30 are provided on the inner surface of each longitudinal side wall 23 to guide the sliding movement of moveable arm 24 within longitudinal guide channel 22. The upper surface of the bottom wall 25 supports an upwardly extending flange 32 and two transversely oriented U-shaped locking pin frames 34. Between the arms of each U-shaped locking pin frame 34 is a hole 36, which hole 36 is formed in the inner wall 23 and the bottom wall 25. A locking pin 37 is provided in each U-shaped locking pin frame 34. Each locking pin 37 has an inner end 38 from which a flange 39 extends upwardly and an outer end 40 from which a detent 41 extends laterally outwardly, detent 41 being sized and shaped to extend through aperture 36.

Activating arm 24 is sized and shaped to slide longitudinally on bottom wall 25 and between longitudinal side walls 23 of longitudinal guide channel 22. The downwardly facing surface of activating arm 24 includes a downwardly extending recess 42 having a wider front portion 43 and a tapered rear portion 45, tapered rear portion 45 being located immediately adjacent tapered inner end 38 of locking pin 37. Extending outwardly from either side of wider front portion 43 are curved ridges 46 that extend rearwardly toward tapered rear portion 45 to define two flange guide channels 47, each guide channel 47 being sized to receive a flange 39 on locking pin 37. Activating arm 24 also includes a longitudinal slot 48 having a rear end 49 and a front end 50. The longitudinal slot 48 is shaped and dimensioned to mate with the upwardly extending flange 32 on the bottom wall 25 of the longitudinal guide channel 22. A coil spring 52 is located on the bottom wall 25 of the guide channel and is mounted in the longitudinal slot 48 between the upwardly extending flange 32 and the rear surface 49 of the longitudinal slot.

Seat plate 18 includes a longitudinal receiving channel 60 having two longitudinal side walls 62. The longitudinal receiving channel 60 is sized and shaped to receive the downwardly extending longitudinal guide channel 22. Each longitudinal side wall 62 is provided with a plurality of notches 64 capable of receiving recesses 41 on outer end 40 of locking pin 37.

When the seat depth adjustment mechanism of the present invention is in its passive state, as shown in FIG. 5, spring 52 extends with one end pushing forwardly against upwardly extending flange 32 and the other end pushing rearwardly against rear end 49 of longitudinal slot 48 in activating arm 24, thereby forcing activating arm 24 rearwardly. The tapered rear portion 45 of downwardly extending recess 42 is forced between the inner ends 38 of locking pins 37, urging them laterally apart. Locking pin flange 39 is guided along flange guide channel 47 to push locking pin 37 outwardly until detents 41 on outer end 40 extend through holes 36 in longitudinal guide channel 22. Each detent 41 will engage a notch 64 in a side wall 62 of longitudinal receiving channel 60 of seat plate 18. The user can actuate the seat depth adjustment mechanism by pushing forward on handle 26 of activating arm 24 in the direction indicated by arrow "a" in fig. 8 and 9. An upwardly extending projection 29 on the upper surface of activating arm 24 will engage the front edge of opening 28 to prevent over-extension of arm 24. As activating arm 24 moves forward, rear end 49 of longitudinal slot 48 moves forward, compressing coil spring 52 against upwardly extending flange 32. Also, the downwardly extending depressions 42 and curved ridges 46 are also moved forward. As shown in fig. 9, flange 39 of locking pin 37 is pulled inwardly along flange guide channel 47, causing locking pin 37 to retract into longitudinal guide channel 22. The locking pin 41 then no longer extends through the aperture 36 and no longer engages the notch 64 in the side wall 62 of the seat plate longitudinal receiving channel 60. The user is free to slide seat pan 20 forward and rearward relative to seat pan 18. When the user reaches a comfortable seat depth, the user releases the handle 26. Coil spring 52 expands forcing movable arm 24 rearward. The tapered end 45 of downwardly extending recess 42 is forced between inner ends 38 of locking pins 37. The locking pin flanges 39 are forced along the flange guide channels 47 until the detents 41 of the locking pins 37 are pushed out of the holes 36 and engage different notches 64 on the side walls 62 of the seat plate longitudinal receiving channel 60, thereby locking the seat pan at the desired depth relative to the seat plate.

Devices for adjusting the depth of the seat of an office chair to accommodate users of different heights and different body shapes are now disclosed. When the user is seated in the seat, he/she can use the device conveniently without the aid of tools. While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that changes may be made in this embodiment using known equivalents without departing from the spirit and scope of the invention. The foregoing description of the preferred embodiments should be taken as illustrative, and not in a limiting sense, the scope of the present invention being defined by the appended claims.

Claims (11)

1. A seat, comprising:

a base;

a seat plate supported above the base;

a seat pan slidably mounted on the seat plate so as to be slidable in a longitudinal direction; and

a longitudinal operating device that slides in a longitudinal guide channel formed in the seat pan, thereby allowing the seat pan to slide longitudinally relative to the seat plate; and

a locking device for locking the seat pan in a fixed longitudinal position relative to the seat plate;

a spring for biasing the longitudinal operation device;

the locking means comprises a laterally movable locking pin for engaging the seat plate;

said laterally movable locking pin is movable by said longitudinally operating means;

wherein the seat pan includes a plurality of notches, the longitudinal guide channel of the seat pan includes at least one hole, and the laterally movable locking pin is movable between an extended position extending through the at least one hole to engage at least one of the plurality of notches and a retracted position retracted from the at least one hole to disengage from at least one of the plurality of notches.

2. A seat as claimed in claim 1, in which the longitudinal operating means comprises guide means for guiding movement of the locking means.

3. The seat of claim 2 wherein the locking pin includes a flange received within the guide such that the locking pin moves laterally in response to movement of the longitudinal operating means.

4. A seat as claimed in claim 3, in which the spring biases the longitudinal operating means to move so that the locking pin is in the extended position.

5. A seat as claimed in claim 4, in which the spring is operated on the longitudinal operating means.

6. The seat of claim 5, wherein the spring is operated on the seat pan.

7. A seat, comprising:

a base;

a seat plate supported above the base;

a seat pan slidably mounted on the seat plate so as to be slidable in a longitudinal direction; and

a longitudinal operating device that slides in a longitudinal guide channel formed in the seat pan, thereby allowing the seat pan to slide longitudinally relative to the seat plate; and

a locking device for locking the seat pan in a fixed longitudinal position relative to the seat plate;

a spring for biasing the longitudinal operation device;

the locking means comprises a laterally movable locking pin for engaging the seat plate;

said laterally movable locking pin being moved by said longitudinally operating means;

wherein the seat pan includes a plurality of notches, the longitudinal guide channel of the seat pan includes at least one hole, the laterally movable locking pin is movable between an extended position extending through the at least one hole to engage at least one of the plurality of notches and a retracted position retracted from the at least one hole to not engage at least one of the plurality of notches;

the longitudinal operating means comprises guide means for guiding the movement of the locking pin;

said locking pin including a flange received within said guide means such that said locking pin moves laterally in response to movement of said longitudinal operating means;

the spring biases the longitudinally operating means to move such that the locking pin is in an extended position, wherein the spring acts on the longitudinally operating means and the seat pan, the locking pin cooperating with the longitudinally operating means.

8. A seat as claimed in claim 7, in which the locking means comprises at least one laterally movable locking pin for engaging the seat pan.

9. The seat of claim 7, wherein the spring is a spring having first and second opposite ends.

10. The seat of claim 9, wherein the first end of the spring urges the longitudinally operating device.

11. The seat of claim 10, wherein the second end of the spring urges the seat pan.