Chair Reclining Mechanism

Abstract

A reclining chair mechanism having its back supported for reclining rotation and forward shifting movement relative to a base, and its seat supported by overslung links which elevate the seat front rapidly upon forward shifting movement of the seat by the reclining rotation of the back, and wherein the seat is connected to the back in a manner such as to maintain the leverage of the occupant's weight upon the seat to counteract the leverage of the occupant's weight upon the back to prevent acceleration in the reclining movement and to maintain the chair in balance in various degrees of recline.

Description

Our invention relates to reclining chairs, and more specifically to linkage mechanism for correlating the movement of the chair back and chair seat with respect to each other and to the common base upon which they are supported.

Reclining chair, as such, are an old and well-developed art that teaches many arrangements for correlating the relative movement of seat and back to each other, as well as to other movable members and to the chair bases upon which they are supported. The present invention is concerned, however, with a linkage of the general kind described which has distinct advantages over those earlier proposed for similar purpose in that it accomplishes previously desired objectives without the disadvantages that heretofore have been associated with the attainment of these objectives.

In particular, the prompt elevation of the forward edge of the seat as an incident to initial reclining movement of the back has been recognized as a desired objective, and has been earlier attained by the overslung linkage which is a component part of this invention. However, the mechanisms heretofore developed which have incorporated overslung seat supporting linkages have usually also been characterized by a rapid shift of influence of the occupant's body weight from the portion of his weight pressing down on the seat to that portion pressing rearward and downward against the back, with the undesirable development of rearward acceleration, i.e., an uncomfortable and even alarming "falling-away" sensation.

Approaching from another tack, the prior art also discloses underslung seat mechanisms, which likewise elevate the seat as an incident to reclining movement of the back, and in such mechanisms, indeed, the initial forward and only then upward movement of the seat increases the effect of the occupant's weight upon the seat, and more than counteracts the effect of that portion of his weight bearing rearwardly and downwardly upon the back. With underslung support of the seat section, however, the elevation of the seat incident to the reclining of the back is much delayed as compared with that of the overslung linkage, and full recline of the back can require more effort to maintain than is conducive to repose.

Wherefore, a principal object of our invention is to utilize fully the advantage of the overslung seat-support linkage, viz., the rapid rise of the seat, particularly at the front edge, upon initial recline of the back, but to simultaneously obviate the difficulties experienced in earlier such attempts, viz., the rapid transfer of influence to the portion of the occupant's body weight exerted against the chair back.

In short, we propose by our invention to have the advantage of the fast-rising seat-elevating movement afforded by an overslung seat-support linkage, while at the same time maintaining a balance between the respect influences of body weight upon the seat and upon the back to maintain the chair in reasonable balance at any position of recline without requiring the auxiliary or artificial motion-retarders which usually increase the muscular effort required to change the attitude of the reclining chair.

It is our further object to provide a reclining chair which attains the above objective by a movement of the seat and lower portion of the backrest forwardly on the chair base, which has the further desirable result of maintaining the center of gravity of the chair and its occupant more or less fixed throughout the reclining movement, as well as minimizing the wall or other clearance required behind the chair to permit the same to be reclined.

Our still further object is to provide a linkage of the kind described in which the respective linkage members are under load in all positions so that inevitable wear and consequent loosening of the riveted pivotal connections of the linkage are not made evident by rattling, as sometime occurs when recline linkages are used on rocking bases in so-called "rocker-recliner" chairs.

Our invention, and its attainment of the foregoing objectives, will be evident from the following specification, taken in conjunction with the accompanying drawings in which

FIG. 1 is a perspective view of our recline linkage as seen from a rear quarter with portions of the seat bracket broken away to better illustrate the remaining parts;

FIG. 1A is a perspective view of only the seat bracket of the linkage, shown in full immediately above its position in FIG. 1 so that its form will be clear;

FIG. 1B is an enlarged perspective view of one element of the linkage shown in the same attitude it assumes in FIG. 1 but removed from context for clearer illustration;

FIG. 2 is a diagrammatic side elevation of the linkage in sitting position, showing its position in the chair suggested by the broken outline; and

FIG. 3 is a similar diagrammatic side elevation of the linkage (and chair) in recline.

FIG. 1 illustrates a linkage in accordance with the invention, one of two such linkages, each a mirror image of the other, required for each chair. The linkage is attached to the base frame 10 of a chair illustrated in broken outline in the drawings, by means of a base bracket 12, and the chair back 14 is mounted on the base by means of a back-support bracket 16 whose path of movement relative to the base bracket is determined by a pair of links 18 and 20. The length and angularity of the back support links 18 and 20 are such that the rotation of the chair back 14 by the reclining movement moves the lower end of the back forwardly of the base through a fixed path incident to such rotation.

The seat 22 of the chair is carried on a seat bracket 24 which is connected for movement conjointly with the back. The seat is supported toward its front end by a link 26 pivoted to the seat bracket 24 and to the base bracket 12 and is supportd adjacent its rear end by its pivotal connection to a bell crank lever 28 which is itself pivotally mounted upon the forward back support link 20, and controlled in its angularity relative thereto by a control link 30 pivoted respectively to the bell crank lever 28 and to the back support bracket 16. The controlled action of the bell crank lever 28 incident to reclining movement of the back is to thrust the seat forwardly, as indicated by the transition from FIG. 2 to FIG. 3. Coincident therewith, the upper end of the seat support link 26 swings upwardly as well as forwardly, and pitches the front end of the seat upwardly.

The forward motion of the seat bracket 24 caused by its pivotal attachment to the bell crank lever 28 is the result of a dual movement, viz., the forward rotation of the forward back-support link 20, and the concurrent movement of the bell crank lever 28 on the link 20 counterclockwise (as seen in the drawings) caused in turn by the counterclockwise rotaion of the back-supporot bracket 16 relative to the forward back-support link 20 and transmitted to the bell crank 28 through the control link 30. As this movement proceeds, the leverage of the occupant's weight upon the seat 22, exerted upon the backrest bracket 16 through the bell crank lever 28 and the control link 30, is multiplied, and counteracts the influence of the rearward pressure of the greater body weight of the upper portion of the body upon the chair back 14 during the recline movement.

When it becomes understood that the function of the bell crank lever 28 is to increase the moment of the seat weight in order to counterbalance the increasing moment of the back weight as the back reclines, and that this countermoment is applied in the preferred embodiment illustrated by forces applied both to the back-support bracket 16 (through the control link 30) and to the forward back-support link 20 (through the bell crank 28), it becomes evident that the countermoment might also be applied by the suitable application of force to either of the back-support links 20 and 18 alone, or indeed to the back rest itself.

For example, we have contemplated the inversion and re-shaping of the bell crank 28, and its connection by means of a control link, such as the link 30, to the base bracket 12 instead of to the back-support bracket 16. In such case, the control link would be in tension instead of in compression, and the counterbalancing effect of the seat weight would be applied as a force opposing the forward rotation of the forward back-support link 20. However, we prefer the illustrated embodiment because as may be appreciated from FIG. 3, the toggle formed by the back support bracket 16 and the rearward back-support 1ink 18 approaches alignment in the full recline position. In these circumstances, the attachment of the control link 30 to the back-support bracket 16, as illustrated, applies a counter-force directly to the back-support bracket 16 to break the toggle "knee," and assist the return of the back rest to the upright position.

We conceive it also possible to connect the control link 30 to the rearmost back-support link 18, again with some re-shaping of the lever 28 to achieve the desired result.

On the other hand, the application of a countermoment directly to the back rest alone, as by pivoting the rearward portion of the seat directly upon an extension of the back-support bracket 16, while effective in counterbalancing the back in the setting of an overslung seat-support linkage, is undesirable for other overriding reasons, viz., because the rearward movement of the lower end of the back away from the seat incident to recline is undesirable for its "shirttail pulling" effect and also for its failure to provide the lower lumbar support that results from the illustrated linkage, in which the lower supporting surface of the back rest moves but little forwardly or rearwardly of the seat during the reclining movement.

Referring in greater detail to the drawings and particularly FIG. 1, it will be seen that the base bracket 12 is essentially a length of angle iron with its vertical flange directed upwardly on the inner side of the bracket, and having at its rear end an upwardly inclined outrigger extension 32. The horizontal flange of the base bracket 12 is provided with a number of anchoring holes 34 for securing the same to a wooden base by means of any suitable fasteners, preferably screws. In each of the drawings, the linkage is depicted as mounted upon a fixed chair base 10, suggesting its application to an ordinary reclining chair, but it should be understood that the linkage is equally applicable to so-called "rocker-recliners" in which case the base mounting bracket 12 is secured in the same fashion to the rocker element instead of to a fixed base as the drawings indicate.

The aforementioned outrigger 32 of the base bracket 12 provides an appropriately positioned point of attachment for the lower end of the rear back-support link 18, the upper end of which is suitably pivoted to the lower end of the back-support bracket 16. The forward back-support link 20 is boomerang shaped and pivoted at the juncture of its two arms to the upstanding flange of the base bracket 12, and at the upper end of its rearwardly and upwardly extending arm to the lower forward end of the back-support bracket 16. It will be apparent that the two links 18 and 20, constituting together with the base bracket 12 and the back-support bracket 16 a four-bar trapezoidal linkage, fully determine the path of movement of the back-support bracket 16, which as shown by comparison of FIGS. 2 and 3, moves forwardly relative to the base bracket 12 as it is rotated counterclockwise by the reclining movement.

As shown especially in FIG. 1, the vertical flange of the base bracket 12 and the side plate of the back support bracket 16 are in the same plane, the back support links 18 and 20 being mounted on the inside surfaces of those brackets. The other, shorter arm 36 of the boomerang-shaped back-support link 20 engages a stop plate 37 secured to the underside of the base bracket 12, and thus determines the upright or sitting position of the linkage.

The back-support bracket 16 has an inwardly extending flange 38 to provide a mounting seat for the frame of the backrest 14, holes 40 being provided therein to secure the back to its supporting bracket by means of screws. The lower end of the flange 38, by its contact with the rear back support link 18, provides a stop to determine the fully reclined position (FIG. 3).

The seat support bracket 24 is a downwardly-open channel in its forward portion, thus providing opposed flanges for mounting the operating linkage of a footrest 42. Such linkage, being irrelevant to the subject matter shown and claimed, is omitted, and may be any suitable footrest support mechanism operated either by the reclining action of the seat and back, or by separate lever action, as may be desired in a particular application.

The rearward, angle portion of the seat bracket 24 (FIG. 1A) includes a depending vertical inner flange 44 of gradually increasing depth from front to rear, providing forwardly of its mid point a convenient site for the pivotal attachment of the forward support link 26. For reasons not relevant here, the flange 44 has a circular boss stamped outwardly therefrom so that the pivot rivet at the upper end of the link 26 may be flush with the forward surface of the flange. The more rearward deepest portion of the flange 44 is the point of the pivotal attachment of the seat bracket to the lower forward pivot of the bell crank lever 28, while rearwardly of its pivotal attachment to the bell crank, the vertical flange 44 of the seat support bracket recedes upwardly to a depth commensurate with its horizontal flange.

The forward portion of the seat bracket 24, as earlier noted, is an inverted channel whose outer flange 46 is pierced coaxially with the rivet hole for the upper pivot of the link 26, to provide a work hole 48 large enough for access by the riveting tool.

Because the seat bracket 24 is mounted outwardly of the back-support links 18 and 20, and outwardly of the bell crank 28 and the control link 30, its rearward portion is shown in broken outline in several of the drawings in order not to obscure those elements of the linkage.

In order to provide the necessary moving clearances for the action of the several members of the linkage in the transition from FIG. 2 to FIG. 3, relief in depth is provided by offsets in the bell crank lever 28, in the control link 30 as well. Specifically as noted particularly in FIG. 1B, the body of the bell crank lever 28, a triangular stamping, occupies three planes. At the site of its pivotal attachment to the seat bracket 24, it is embossed outwardly as at 50, and at the site of its pivotal attachment to the forward back support link 20, it is embossed inwardly as at 52, leaving its third pivot site 54 in the mid-plane. Clearance for the movement of the control link 30 is thus provided between the vertical flange 44 of the seat bracket and the forward back support link 20. The control link 30 itself is offset at its upper end to provide clearance for its passage over the head of the upper pivot rivet of the back-support link 20.

Because of the balance achieved in this linkage, it is possible to construct the upholstered seat and arms for attachment as an integral unit to the seat bracket 24. This is particularly desirable in the rocker-recliner chairs for it not only eliminates the wear and noise resulting from movement of the seat within and relative to the arm frames, it also lends greater flexibility of styling as contrasted to chairs of current manufacture having a two-phase reclining movement, i.e., a first rearward shifting of the seat to extend the leg rest to an intermediate so-called "TV" position, essentially without substantial reclining movement of the back. Such chairs, by requiring fixed arm rests against which the occupant can push himself and the seat rearwardly, are limitd in their styling capabilities inasmuch as they cannot satisfactorily use a T-shaped seat cushion.

As earlier indicated, the sitting position of the chair is determined by the engagement of the lower arm 36 of the forward, boomerang back support link 20 with the stop plate 37 secured to the horizontal flange of the base bracket 12. This is shown both in FIG. 1 and FIG. 2. Particularly from FIG. 2 it will be noticed that the support link 26 for the seat is inclined upwardly and rearwardly in sitting position so that the occupant's weight upon the seat maintains a compressive loading not only upon the support link 26 of the seat, but also upon the control link 30. It will further be apparent that each one of the pivots of the linkage likewise remains under load in every conceivable position the linkage may occupy. This constant loading has the advantage, as earlier indicated, of eliminating clicking noise in the linkage when the same is used in a rocker-recliner, i.e., when the linkage in the position shown in FIG. 2 is rocked back and forth without relative movement of the seat and back of the chair.

Further with regard to FIGS. 2 and 3, it is apparent that as the back 14 is reclined, its lower end, being immediately adjacent to the back support bracket 16, moves forwardly, as does the seat. The center of gravity of the occupant, different of course in persons of different stature, is usually located in the lower abdomen. The position of that center, as may be appreciated by comparison of FIGS. 2 and 3, will remain relatively unchanged between the sitting and the fully reclined positions, and in intermediate positions as well. This tends to provide good inherent balance without the need either of counterbalancing springs, or of motion-retarders or snubbers, such as are often required either to compensate for over-shifting of body weight or to provide artificial retardation for movement that would otherwise be duly accelerated or abrupt.

The features of our invention believed new and patentable are set forth in the appended claims.

Claims

What is claimed is:

1. In a reclining chair having a base, a seat, a back, and linkage means at each side of the chair interconnecting said back and seat and mounting the same upon said base for movement relative thereto and to each other from a sitting position to a reclining position,

the improvement wherein said linkage means supports the back upon the base for forward shifting movement through a fixed path relative to the base as an incident to recline of the back and includes at least one back link extending upwardly from the base to back and pivoted to both for rotation forwardly on the base by the recline of the back, a seat link connecting the forward portion of the seat to the base and being inclined rearwardly and upwardly from the base to the seat when in said sitting position, and a lever pivoted on said back link and connected by a control link to a portion of said chair other than said seat and with respect to which said back link is relatively movable upon the recline of the back, said lever being also pivoted to the rearward portion of the seat to support the seat and to move the seat forwardly relative to the base of the recline of the back.

2. The improvement of claim 1 wherein said back is supported by two links each pivoted to the base and extending upwardly therefrom to pivotal connections to the back to form a trapezoidal four-bar linkage with said base and back and wherein said lever is pivoted to the forwardmost one of said two links, and said control link connects said lever to one of said base, said back, or the other of said two links.

3. The improvement claimed in claim 1 wherein said control link rotates said lever to advance the pivotal attachment of the lever to the seat faster than the pivot of the lever to said back link.

4. The improvement claimed in claim 2 wherein said lever is a bell crank whose pivot to said forward-most link is disposed between and above the pivotal connections of the bell crank to said seat and to said control link, and said control link is pivoted to said back.