|Publication number||US3099487 A|
|Publication date||30 Jul 1963|
|Filing date||21 May 1962|
|Priority date||21 May 1962|
|Also published as||DE1283458B|
|Publication number||US 3099487 A, US 3099487A, US-A-3099487, US3099487 A, US3099487A|
|Inventors||Edward M Knabusch, Edwin J Shoemaker|
|Original Assignee||La Z Boy Chair Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (29), Classifications (11)|
|External Links: USPTO, USPTO Assignment, Espacenet|
July 1963 E. M. KNABUSCH ETAL 3,099,487
LEG REST FIXTURE AND SUPPLEMENTAL HOLDING MECHANISM Filed May 21, 1962 2 Sheets-Sheet l July 30, 1963 E M. KNABUSCH ETAL 3,099,437
LEG REST FIXTURE AND SUPPLEMENTAL HOLDING MECHANISM Filed May 21, 1962 2 Sheets-Sheet 2 INVENTOM jguari M X774; us a); fla/Ydrj -77 fiacvfia/kwt United States Patent 3,099,487 LEG REST FIXTURE AND SUPPLEMENTAL HOLDING MECHANISM Edward M. Knabusch and Edwin J. Shoemaker, Monroe, Mich, assignors to La-Z-Boy Chair Company, Monroe, Mich, a corporation of Michigan Filed May 21, 1962, Ser. No. 196,059
3 Claims. (Cl. 297429) This invention relates to chairs having extensible and retractable leg rests, and more particularly constitutes an improvement over the platform rocking chair illustrated and described in our copending application Serial No. 125,874, dated July 21, 1961.
The chair of the aforementioned copending application includes a leg rest which is secured to the chair by a pair of laterally spaced pantograph mechanisms which are actuated by means including a rotatable shaft for moving the leg rest into a lower retracted position or an extended, raised leg-supporting position. The leg rest is then held in such positions by the pantograph mechanisms and the actuating means.
When the leg rest is in a retracted position it is desirable that it fit tightly against the front end of the chair. Occasionally, however, the pantograph mechanism and actuating means will Wear and, consequently, develop some slack or play causing the retracted leg rest to hang outwardly from the rest of the chair and thereby become an obstacle over which a person might inadvertently trip. Furthermore, an outwardly hanging leg rest detracts from the appearance of the chair.
The present invention includes a supplemental holding mechanism for solving this problem which coacts with the rotatable shaft to impose an inward pull on the leg rest so that it will be resiliently held tightly against the chair when it is in its retracted position. The supplemental holding mechanism also helps to raise the leg rest toward its raised leg-supporting position and to hold it in such a position.
Accordingly, important objects of this invention are to improve a chair having a leg rest which is held in a lower, retracted position or a raised leg-supporting position by a pantograph mechanism and actuating means including a rotatable shaft, by providing a supplemental holding mechanism which coacts with the rotatable shaft to resiliently hold the leg rest in its retracted position; and to provide such a supplemental holding mechanism including a toggle joint comprising a first link fastened to the rotatable shaft and a second link which is bent around the rotatable shaft with one of its ends pivotally connected to the first link and its opposite end connected to spring means which imposes reversely directed moments on the rotatable actuating shaft when the first and second links are moved into over-toggle positions for resiliently holding the leg rest in either a retracted or a raised position.
With the above, as well as other, and in certain cases more detailed objects in view, a preferred but illustrative embodiment of the invention is shown in the accompanying drawing in which:
FIGURE 1 is a view in side elevation of a platform rocking chair having a leg rest and operating mechanism therefor, embodying features of the present invention;
FIGURE 2 is an enlarged broken plan view of the seat frame of the chair illustrated in FIGURE 1;
FIGURE 3 is a sectional view of the structure illustrated in FIGURE 2, taken on the line 3-3 thereof showing the leg rest in its retracted position and the rocker in horizontal position;
FIGURE 4 is an enlarged, broken side view of a supplemental holding mechanism constructed in accordance with certain of the concepts of the present invention; and
Patented July 30, 1963 FIGURE 5 is a plan view of the supplemental holding mechanism illustrated in FIGURE 4.
One embodiment of the invention is illustrated in the drawings as including a chair, representatively illustrated as being a platform rocker chair, having a back frame portion 12 containing a back cushion 14 fixed with respect to a seat frame 16 having a resiliently supported seat cushion 17 thereon. The seat frame 16 includes a pair of laterally spaced side frame members 18, 20 which are joined at the rear by a rail 21 and at the front by a rail 22. The side members are further interconnected by a crossbar 24 at the front, upper end thereof. Rockers 26, 28 secured on the inside surface of the side frame members 18, 20 engage the upper surface of side members of a base supporting frame 30 in rockable relationship therewith. The rockers 26, 28 and the side members of the base 30 are interconnected by double coil spring devices 3-2 which are of a form well known in the art. It should be understood that the seat frame 16 can be fixedly mounted upon a fixed platform or base, or be connected to such a base for swiveling movement rather than rocking movement.
The illustrated embodiment of the invention further includes a leg rest 34- supported on the seat frame 16 for movement between an inactive, lowered or retracted position, as illustrated in FlGURES l3, and a raised, legsupporting position, as illustrated in dotted lines in FIG- URE 1, by means of a pair of spaced pantograph mechanisms 36, 38 each of which includes a first pair of links 40, 42 secured in scissor relation by a pivot 44. The upper end of the link 42 is secured to a bracket 46 on the underside of the crossarm 24- by means of .a pivot 48. A U-shaped link 50 comprising a crossarm 51 joining a pair of laterally spaced legs 52, 54 is operatively associated with the rear end of the link 40 by means of a pivot 56 which interconnects the rear end of the link 40 and the free end of the leg 54. An actuating shaft 58 of square section extends through openings in each of the legs 52, 54 adjacent the joined ends of the laterally spaced legs 52, 54 and has end portions which are rotatably carried by bushings 60 supported in the side frame members 18, 20. The openings in the legs 52, 54 are squared to snugly fit the shaft 58. A supplemental holding mechanism is operatively associated with one end of the actuating shaft 58 and, as will be subsequently discussed in greater detail, coacts therewith to hold the leg rest 34 tightly against the chair frame when the leg rest is in its retracted position. I
The actuating shaft 58 is adapted to be rotated by means of an operating arm 62 secured on the outer end thereof to produce movement of the leg rest 34 from its retracted position to its leg-supporting position. When the operating arm 62 is positioned forwardly as shown in solid lines on FIGURE 1, an outwardly directed stop tab 64 on each leg portion 54 engages a forward surface 66 of a clearance notch 67 in the rear end of the link 40. When the arm 62 is moved rearwardly into the position shown in broken lines in FIGURE 1, the leg rest 34 is moved into its leg-supporting position and held therein by the engagement of the stop tab 64 with the upper surface of an extending finger 68 at the end of the link .40. The relationship between the surface 66 and the upper surface of the extending finger 68 is such that the operating arm 62 moves slightly more than as illustrated in FIGURE 1, to produce movement of the leg portion 54 between the points at which the stop tab 64 will engage the forward and rearward surfaces of the clearance notch 67, respectively. When the leg rest 34 is in its leg-supporting position, the relationship of the shaft 58 and the pivot 56 is such that they are in an on, or over-toggle relationship so as to lock the leg rest 34 in its'leg-supporting position.
Returning now to a description of the pantograph mechanisms 36, 38 which support the leg rest 34 on the chair frame, each such mechanism further includes a second set of links74, 76 which are disposed in scissor relationship and secured together by a pivot 72. The upper end of the link 74 is connected to the upper end of the link 40 by means of a pivot 78 and its lower end is connected by means of a pivot 82 to the rear end of a link 84 having its opposite end connected to a bracket 86 on the underside of the leg rest 34 by means of a pivot 88. The lower end of the link 76 is connected to the lower end of the link 42 by means of a pivot 90 and its opposite end is connected to the bracket 86 on the leg rest 34 by means of a pivot 92 near the upper end of the leg rest 34 when it is in its inactive position.
The lengths of the various links on either side of the pivots are such as to produce a desired movement of the leg rest 34 from its retracted position to a horizontally extending or leg-supporting position. The operation of the links for so moving the leg rest 34 has been explained in more detail in Patent No. 2,963,077, issued December 6, 1961 to E. M. Knabusch, et al., for Platform Rocker, and will not be described further herein.
The main concept of the present invention embodies the manner in which the leg rest 34 is held against the chair when it is in its retracted position. As was indicated above, it has been found that supporting means having a number of links may develop a certain amount of slack after a period of use such that the leg rest 34 will hang outwardly of the chair when it is in its retracted position. Such slack can develop through wear at the bearing points between the various pivots and links and between the bearing points at the U-shaped links 50 and the actuating arm 58. Therefore, in accordance with certain of the concepts of the present invention, a supplemental holding mechanism 70 is operatively associated with the actuating shaft 58 to cause the pantograph mechanisms 36, 38 .to resiliently hold the retracted leg rest 34 tightly against the seat frame 16.
" The illustrated embodiment of the supplemental holding mechanism 70 includes a spring actuated toggle joint which preferably comprises a link 94 having a square hole 95 in one end thereof which snugly fits the surfaces of the squared actuating shaft 58. The link 94 is representatively illustrated as being located on the shaft 58 between the legs 52, 54 of one of the U-shaped links 50 and is so arranged that the outer end thereof extends generally downwardly when the leg rest 34 is in its retracted position. The outer end of the link 94 has an outwardly directed, offset tip portion 96 which extends through an aperture 98 in one end 99 of a bent link 100 for providing pivotal movement therebetween. The link 100 is bent upwardly and over the crossarm 51 of the U-shaped link 50 such that its opposite end 101 is offset at a point rearwardly from its pivoted end 99. One end of an elongated spring 102 connects to fixed support means, forexample, to a screw 104 secured on the inside surface of the rocker 26. The opposite end of the spring 102 connects to the offset end 101 of the bent link 100 for imposing a rearward pull thereon.
When the leg rest 34 is in its retracted position the spring 102 will pull the bent link 100 rearwardly so as to impose a clockwise movement M on the actuating shaft 58. Force components from the shaft 58 are transmitted through the U-shaped link 50 to remove any slack that exists in the supporting pantograph mechanisms 36, 38. Accordingly, the leg rest 34 is resiliently held tightly against the seat frame 16. When the leg rest 34 is moved toward its horizontally extended or raised leg-supporting position, the actuating shaft 58 will rotate the link element 94 in a counterclockwise direction as viewed in FIGURES 3 and 4 causing the bent link 100 to initially move against the force of the spring 102 until the offset tip portion 96 of the link 94 passes upwardly through a horizontal plane including the centerline of the actuating shaft 58 and snaps into an over-toggle position at which point the spring force 102 will impose a counterclockwise moment M on the actuating shaft 58. Force components acting through the actuating arm 58, the U-shaped links 50 and the extensible pantograph mechanisms 36, 38 will accordingly act to raise the leg rest 34 toward and to resiliently hold it in its horizontally extended or raised leg-supporting position.
The elements of the illustrated embodiment of the supplemental holding mechanism 70 are so proportioned that they provide a sufiicient force to take up any slack which might otherwise cause the leg rest 34 to hang outwardly of the chair but yet are proportioned to enable the operating handle 62 to be easily operated while moving the leg rest 34 between its retracted and extended positions. Furthermore, the elements of the supplemental holding mechanism 70 can be quickly assembled by merely sliding the link 94 on the shaft 58, inserting the tip portion 96 through the aperture 98 in the bent link 100 and connecting the spring 102 between the screw 104 and the link 100.
While it will be apparent that the embodiment of the invention herein disclosed is well calculated to fulfill the objects of the invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.
What is claimed is:
1. In a chair structure, the combination of a seat frame, a leg rest, means including extensible linkage means securing said leg rest to said seat frame for movement between a retracted position and a raised leg-supporting position, means operatively connected to said extensible linkage means for moving said leg rest into its retracted or raised leg-supporting positions including a rotatable transverse shaft adapted to be manually actuated, a first link non-rotatably connected to said shaft, a curved generally sickle shaped link having one end pi-votally connected to said first link on one side fore and aft of said shaft and the opposite end disposed on the other side of said shaft when said leg rest is in its retracted position, and resilient means connected to the opposite :end of said curved link for moving said leg rest operating means in a direction to cause said extensible linkage means to resiliently hold said leg rest against said seat frame when said leg rest is in its retracted position.
2. In a chair structure, the combination of a seat frame, a leg rest, means including extensible linkage means securing said leg rest to said seat frame for movement between a retracted position and a raised leg-supporting position, means operatively connected to said extensible linkage means for moving said leg rest into its retracted or raised leg-supporting positions, a first link operatively connected to said leg rest operating means and having an outwardly directed offset tip, a bent link having olfset ends, one of said offset ends having an aperture therein through which said ofi'set tip fits for pivotally interconnecting said first link and said bent link, and spring means connected to the other of said oflset ends for moving said leg rest operating means in a direction to cause said linkage means to resiliently hold said leg rest against said seat frame when said leg rest is in its retracted position, for raising said leg rest when it is moved a predetermined amount toward its leg-supporting position and for resiliently holding said leg rest in its leg-supporting position.
3. In a chair structure, the combination of a seat frame, a leg rest, means including extensible linkage means securing said leg rest to said seat frame for movement between a retracted position and a raised leg-supporting position, means including a rotatable shaft operatively connected to said extensible linkage means for moving said leg rest into its retracted or raised leg-supporting positions, a first link connected to said rotatable shaft and having an offset tip directed outwardly therefrom, a
bent link having offset ends, one of said offset ends having an aperture therein through which said offset tip fits for pivotally interconnecting, said first link and said bent link, and spring means connected to the other of said offset ends for rotating said shaft in a direction to cause said lin kage means to resiliently hold said leg rest against said seat frame when said leg rest is in its retracted position, for raising said leg rest when it is moved a predetermined References Cited in the file of this patent UNITED STATES PATENTS Kirkorian May 22, 195 6 Knabusch et al Dec. 24, 1957 Knabusch et a1 Dec. 6, 1960
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|U.S. Classification||297/423.19, 297/69, 297/423.26, 297/DIG.700|
|International Classification||A47C7/50, A47C1/034|
|Cooperative Classification||A47C1/0345, A47C7/506, Y10S297/07|
|European Classification||A47C1/034F2, A47C7/50G|