US 3429612 A
Description (OCR text may contain errors)
Feb. 25, 1969 COBB 3,429,612
CHAIRS EQUIPPED WITH LEGRESTS 0R FOOTRESTS Filed Feb. 20, 1967 Sheet of s Fig. 1.
Feb. 25, 1969 'w. R. cosa CHAIRS EQUIPPED WITH LEGRESTS OR FOOTRESTS Filed Feb. 2d, 196? She et Fig. 2.
INVENTOR Feb. 25 1969 w a coaa 3,429,612 camps mm'rrsn II!!! wsnss'rs on tomb-rs Filed m 20. 1967 Sbuf of 3' Fig; 3.
United States Patent Office 3,429,612 Patented Feb. 25, 1969 3,429,612 CHAIRS EQUIPPED WITH LEGRESTS R FOOTRESTS William Reginald Cobb, Hunters Lodge, Mill Lane, Old Harlow, Essex, England Filed Feb. 20, 1967, Ser. No. 618,288 U.S. Cl. 297-75 Int. Cl. A47e 7/50, 1/02 4 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to action linkage mechanism in and for chairs of the kind having a stationary chair-frame structure and a legrest or footrest movable between an out-of use position beneath the chair seat and an in-use position where it projects forwardly from the front of the chair and which can be brought into position for use by tilting the seat and backrest members toward a reclining position.
An object of the invention is to provide a robust but simple and inexpensive mechanism which offers a useful legrest projection without uncomfortably deep seating and without recourse to forms of mechanism such as lazytongs and parallelograms or trapeze-type movements. Such mechanisms have heretofore been proposed in connection with leg rests for reclining chairs but these mechanisms have an inherent disadvantage in that the legrest lacks rigidity owing to the accumulation of lost motion at the several pivoted joints involved and the accumulated flexibility resulting from a succession of thin metal links.
A further object of the invention is to provide an action linkage mechanism in or for a chair which will provide stable support for the user in three favoured positions; a normal upright position; a semi-reclined position with legrest, and a fully reclined position.
A still further object of the invention is to provide a balanced movement between these positions so that only slight elfort is necessary to change from one position to another and any intermediate position may be selected between at least the second and third positions.
For a chair of the kind aforesaid, the present invention provides a legrest actuating mechanism comprising a simple bell-crank lever to swing the legrest between its out of use position and its position of use, and a control link to govern the rate at which the legrest is turned relative to the rate at which the moveable seat member is tilted.
An embodiment of the invention will now be described, by way of example with reference to the accompanying drawings in which:
FIG. 1 illustrates diagrammatically a chair incorporating an action linkage mechanism according to the present invention, the chair being in a normal upright condition;
FIG. 2 shows the chair of FIG. 1 in a semi-reclined position; and
FIG. 3 illustrates a third fully reclined position assumed for maximum comfort and full relaxation.
Referring firstly to FIG. 1 in which a pair of side members or arm rests 1 (only one of which is shown) are interconnected by rail members 2 and 3. The latter rearward member 3 carries a mounting bracket 4 which is pivotally connected at 5 with a main carrier arm 6 which is the back-bone or foundation upon which the mechanism of the chair is mounted. The carrier arm 6 is supported toward its forward end by the rail member 2, further forward the arm 6 is pivotally mounted at 7 to a bell crank lever 8. The bell crank lever 8 is pivotally mounted at 9 toward the front of a seat frame 10 by means of a bracket (not shown). The opposite end of the bell crank lever is pivotally connected at 12 with a leg rest-mounting bracket 13, the inclination of which is controlled at all times by a control link 14 one end of which is pivoted at 15 to the bracket 13 and the other end is pivoted at 16 adjacent the forward end of the carrier arm 6.
The seat frame 10 is pivotally supported at 17 toward its rear end by a swingable link 18 the lower end of which is pivoted at 19 to the carrier arm 6.
Referring now to FIGS. 2 and 3, when the chair ,is occupied the centre of gravity of the movable seat 30 and back portion 31 is about 5 inches above the seat level and about 4 inches in front of the pivot 19, and if the user grips the armrests and applies pressure to the back rest the centre of gravity has to be raised very slightly as the seat and back rest moves rearwardly and the link 18 pivots about the point 19, the pivot point 17 describing an arc. The rearward movement of the seat frame urges the bell crank lever 8 to turn about the pivot point 7 so that the opposite end of the bell crank describes an arc around pivot 7 so as to raise the legrest bracket 13 and project it forwardly. The turning movement of this bracket is controlled by the link 14 which is urged to pivot about the point 16 and the geometric arrangement is such that the are described by the pivot point 15 around the pivot point 16 almost coincides with the are described by pivot point 12 about pivot point 7 during the first part of the movement. This arrangement is adopted in order to delay the turning movement of the legrest bracket 13 until the height of pivot 12 is sufiicient to allow the upholstered legrest panel 20 to clear the floor as it swings toward the position of use illustrated by FIG. 2.
An upholstered plywood front-board 34 is hinged by cover material to the front of the seat frame and is raised as part of the footrest mechanism through pivot link 35.
Reference to FIG. 2 will show that the rearward movement of the seat and back assembly is temporarily arrested by the abutment of link 18 with a stud 21 which is mounted upon the carrier arm 6. In this position the centre of gravity of the movable seat and back rest, when the chair is occupied, is only a little forward of the rear mounting pivot point 5 of the carrier arm 6. Further pressure upon the back rest is therefore resisted by the stud 21 and a turning moment is exerted upon the carrier arm 6 around the mounting pivot point 5.
Considering the chair as it moves from the position illustrated in FIG. 2 to the position illustrated in FIG. 3, the carrier arm is free at its forward end to rise and it is urged to do so as the centre of gravity passes over the rear pivot point 5 through an arc of above 12 or 13 inches and for a distance of about 3" (on a sector of about 3 degrees) until this movement is arrested by a pivoted elbow joint provided between rail 2 and carrier arm 6 and comprising two links 22 and 23 the opening movement of which is restricted by a stud 24 as illustrated in FIG. 3.
The arc through which the centre of gravity thus passes is almost a horizontal line and the user may therefore find stability in any position between that illustrated in FIG. 2 and that illustrated in FIG. 3. To assist further in providing such stability an adjustable frictional resistance is provided by means of a washer of a friction material between the links 22 and 23 at the elbow joint which is pivoted upon a threaded stud and provided with a manually adjusted wing-nut 33.
The are through which the centre of gravity passes between the positions of FIGS. 1 and 2 'allows the centre of gravity to rise and fall only slightly so that although there is a slight bias toward both positions it is insufficient to prevent a user adopting a position with the legrest only partly raised in the movement between positions as shown in FIG. 1 and FIG. 2.
Where the fully reclining position is not required the invention may be modified as follows:
The main carrier arm 6 is deleted together with the elbow-joint links 22 and 23. Pivot 7 of the bell crank lever 8, pivot 16 and pivot 19 of the swingable link 18 are pivotally attached to fixed points on the stationary chair frame structure 1 or frame parts rigidly connected thereto.
In a further embodiment of the invention the back rest may be articulated relative to the seat by means of an interconnecting pivot so as to increase the angle between the seat and the backrest progressively as they move toward the fully reclined position. This would be possible by pivoting the backrest frame to the seat frame at a point adjacent the bottom front of the backrest frame and connecting the bottom back of the backrest frame, for example, to the mounting bracket 4 by means of a pivoted link.
What I claim is:
1. In a chair having a stationary frame part, seat and backrest members moveable relative to said frame part toward a reclining position, and a legrest moveable 'between an out of use position where it is substantially horizontal and inverted beneath the seat member and an inuse position where it extends forwardly in front of the seat; a linkage mechanism including a bell-crank lever which is pivoted at the root of the arms thereof toward the forward end of the seat member, and a legrest mounting bracket having at least two pivotal connections there to, one to a first arm of said bell-crank lever and one to a control link, the opposite end of the control link and the second arm of the bell-crank lever being pivoted at spaced apart points to a main carrier arm which is pivotally anchored to the stationary frame part at a point some inches below the rear of the seat member, the forward end of the carrier arm being supported by stop means provided on the stationary frame part, the rear of the seat member being supported by a swingable link to the carrier arm and the front of the seat being supported, in the normal position, by stop means such as a cross rail between arm members of the stationary frame part, and by the said second arm of the bell-crank lever when the seat is moved toward a reclining position, this movement turning the bell-crank lever around the pivot connecting the second arm of the bell-crank lever with the carrier arm and also around the pivot connecting the root of the bell-crank lever arms with the forward part of the seat member, the said first arm of the bell-crank lever swinging the legrest mounting bracket forwardly and upwardly as it is turned about its pivotal connection with the bell-crank lever to a position for use by the control link, stop means being provided to limit such movement when the legrest is at a desired angle relative to the seat member, so that further rearward pressure will exert a turning moment upon the carrier arm around the anchorage pivot by which it is mounted beneath the seat member to the stationary part, thereby permitting the moveable parts to reach a fully reclined position where final stop means prevent further movement relative to the stationary part.
2. For a reclining chair having a moveable seat and backrest and a retractable legrest, an action linkage mechanism as claimed in claim 1, and including a friction device providing adjustable resistance to movement of the carrier arm relative to the stationary frame part.
3. In a chair having a stationary frame part, seat and backrest members moveable relative to said frame part toward a semi-reclining position, and a legrest moveable between an out of use position where it is substantially horizontal and inverted beneath the seat member and an inuse position Where it extends forwardly in front of the seat; a linkage mechanism including a bell-crank lever which is pivoted at the root of the arms thereof toward the forward end of the seat member, and a legrest mounting bracket having at least two pivotal connections thereto, one to a first arm of said bell-crank lever and one to a control link, the opposite end of the control link and the second arm of the bell-crank lever being pivoted at spaced apart points to the stationary frame part, the rear of the seat being supported by a swingable link to the stationary frame part and the front of the seat being supported, in the normal position by stop means such as a cross-rail between arm members of the stationary frame part, and by said second 'arm of the bell-crank lever when the seat is moved toward a semi-reclining position, this movement turning the bell-crank lever around the pivot connecting the second arm of the bell-crank lever with the stationary frame part and also around the pivot connecting the root of the bell-crank lever arms with the forward part of the seat member, the said first arm of the bell-crank lever swinging the legrest mounting bracket forwardly and upwardly as it is turned about its pivotal connection with the bell-crank lever to a position for use by the control link, stop means being provided to limit such movement when the legrest is at a desired angle relative to the seat membar.
4. For a legrest chair having a moveable seat and backrest and a retractable legrest, an action linkage mech 'anism as claimed in claim 3.
References Cited UNITED STATES PATENTS 2,774,412 12/1956 Luckhardt 297-88 X 2,976,913 3/ 1961 Schliephacke 297-88 3,003,814 10/1961 Schliephacke 297-88 3,041,105 6/1962 Fletcher 297-90 X 3,081,128 3/1963 Schliephacke 297-88 3,096,118 7/1963 Dubeck 297- 3,100,668 8/1963 Rogers, et al 297-75 X 3,244,449 4/1966 R 297-75 CASMIR A. NUNBERG, Primary Examiner.
US. Cl X.R. 297-429