|Publication number||US2784767 A|
|Publication date||Mar 12, 1957|
|Filing date||Apr 28, 1955|
|Priority date||Apr 28, 1955|
|Publication number||US 2784767 A, US 2784767A, US-A-2784767, US2784767 A, US2784767A|
|Inventors||Soderberg Gustaf A|
|Original Assignee||Manton Ahlberg H, Siegfried J Ullmann|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (14), Classifications (10)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Ma'ch 12, 1957 G, A, SQDERBERG. 2,784976? CONTROL FOR TILTING SEAT AND 'BACK OF' -PSTURE CHAIRS 2 Sheets-Sheet l Filed April 28, 1955 INVENTOR )ZQ'QLM ATTORNEYS March A2, 1957 G. A. SODERBERG @gdwm? CONTROL FOR TILTING SEAT ND BACK OF POSTURE CHAIRS /9 9g INVENTOR ATTORNEYS.
United States Patent O CONTROL FOR TILTING SEA'IYALND BACK. 0F POSTURE CHAIRS Gusta Ar.` Soderberg, Bridgeport,` Conn., assigner, by
dii'ect-` andmesne assignments, of thirty-three and onethird1 percent to H. Manton Ahlherg and` thirty-three andone-third percent tot Siegfried J. Ulimann, Stratford', Conn.
Application April 28, 1955,.SerialiNo. 504,477
9 Claims. Cl. 155-77) Thisy invention relates to` a control or iron for office chairs, particularlyF to a` control for the tilting seat and back` of the. so-called1 posture` chairs, and` has foran object to provide an improved construction of control for the tilting seat and back of this type of chair which will: use a torque bar formed` of a heatftreated steel alloy to control the action instead of the usual coil springs or rubber cylinders.
Another object is` to provide a construction which will permit the rear edge or rear part of the seat to'be lowered or tilted downwardly about a pivot at or near the front edge of the seat, and the backrest may be tilted backwardly without relative vertical or` up. and down movement between the back and the seat which would tend` to cause disarrangement or untidiness of the garments of the user ofthe chair.
It .is a further object to provide a` construction and arragement in which the height ofy the front edge oi the seat does not vary or change materially during tilting movement, so that` when the back and seat are tilted backwardly the users feet can` maintain the` usual and comfortable position on the oor. Also, although the back is pivoted` to tilt on a pivot at substantially the center of the seat, it andv the seat can tilt backwardly without changing the height of the front edgel of the seat; or in other words, the rear edge of the seat can tilt` or shift downwardly with the back but the front edge of the seat remains at the same height.
It is also an object to provide a control construction of this type withmeans. whereby the angular position of the back rest with respect to the seat and its height above theseat may be readily adjusted- A further object is to provide simple and improved means whereby the height of the chair seat may be readily and easily adjusted,
Withv the foregoing and other objects in view, l have devised the construction illustrated in the accompanying drawings. forming a part of this specification. lt is, howeven, to be understood the inventionis not limited to the specic details of construction and arrangement shown, but may embody various changes and` modications within thescope` of the invention.
In these drawings:
Fig. 1 is a top plan view of this control;
Fig, 2 is a side view looking toward. the bottom of Fisq 1;
Fig. 3 is a front view looking from the left ol` Figs. l and2;
Fig.` 4' isV aA detail section of a` portion of the support for the front edge portion of the seat;
Fig. 5 is a side view of one of the elements ofthe support;
Fig. 6 is a side view of another element of the support;
Fig. 7 isa partial` elevation and partial vertical section of the height adjusting means forthe chair seat;
Fig. 8V is a transverse section substantially on line of:` Fig. 7 with the cover for the support-ing hub removed, and
Fig. 9.V is an end= view of the release looking from the right of Fig. 'Z-. j
This control` device or iron for a. posture type chair comprises ai body; member 10 extending transversely from left to? rightA under the seatA shown ini dot-and-dash lines ll. Thisbody member may be oi different forms, but as shown` is preferably of substantially U-shaped cross section including spaced upright longitudinal side walls-.12 and l.- connected bya transverse bottom; wall 14, andl these wallsare connected` at their opposite ends by the upright endtransversef walls` 15, and atthe center the body. member has adownwardly extending lug or extension. 16. havinga.v socket lf to.- receive theupper reduced end olil the screw post 18V for supporting the chair seat and back on the usual type obase` support or feet 19. This body may` belsecured to-the upper' endofthis post by 'any suitable means, such, for.l example, asA the transverse pin 20. The body member is provided with baclcwardly extending arms 211 adjacentits.- opposite ends forming bumper` supports` for suitable bumpers 22 of any` suitable material, such, for example, as soft rubber, and:l located in a-propen position to engage aY part of the tiltingf support` for` the back: and. rear portion ot` the seat to limitthe tilting movement of. these members, as will later bef described.
Extending longitudinally in the body member l0 betweenthe sidewalls i2 and 13., and passing through openingsA i'nf the end walls l5A providing a bearing@ therefor, is a` torque bar 23. which is` preferably formed of heattreated. alloy steel so: as to. have the required strength and resiliency to; control` the. tilting movements.` of the seat and bach, and toreturn. and maintain. them in the forward and normal positionsy when the tilting pressure isreleased. Atits` right-,hand endll this bar projects from the ende of the body lil, and mounted on` it is` al torque` bar adjustment holder 24: secured-r to` the bar by any suitablemeans, such asset screws 25. This holder includes aA forwardly and downwardly. projecting arm 26A engagingL the free end ofV an adjusting, screwl 27- threaded` for adjustmentin. thesupporting lug 28 on a` laterally extend ing bracketarm. 29 of thebody lil: This screw is providedr with. a hand. wheel. 30 tor operating it to shift the. position. of the: arm. 26ito adjust the` torsional tension in the bar 26,. aswill. later be described.
Extending forwardly from` the body 10 are. right andleft front carriersk 31, and 32. These: carriers areV ofinverted` U` shapein. cross` section` comprising laterally spacedi upright side. walls` 33- connected by a transverse top. wall 34, and. they are secured to body member 10 adjacent the opposite endsthereot by-4 upright` forwardly extending, arms` 35` located. between the side walls 33t and secured, to them-.by suitable means, such, for example, as
the` transverse rivets `36. Attheir forward` or free ends these carriers support the front spideirarm 3.7- extending across under. the. front portion of the` seat il. fom left toA right, ande the seat` is. secured theretov by any suitable means,` such, for example, asiscrews (snot shown) through openings tiinV this arm. This spider arm isY preferably' of channel' shape in cross. section to` secure strength and stiffness. in proportionA to the amountot` metal in it, andA it. includesy the. spaced. upright` flanges 39 connected by the. transverse. top` wall` 40, and this` top wall may be cut away or` provided withr elongated' openings 41- to reduce its weight.. This spider arm- 37 isr connected with the-.frontcarriersl and.3,2-so, asto` be supported thereby, by uprightA angular membersy 42` including a` tapered upright` body portion 43 with a` laterally extending liorizontal ilange` 44 at, its upper` end. This flange seats: at the. under side. of the top wall 40 of the bar 37 between the flanges 39f andV is secured thereto` by' any suitable` means-,. such,.forexample, as. the-rivets.n 45. These sup.- ports or angular members 4Z are connected one to each of the carriers 31 and 32 by means of an upright link 46 pivoted adjacent its lower end to the forward ends of the carriers 31 and 32 by a transverse pivot rivet 47 passing through the side members of the carrier and the opening 48 in this link. This thus forms a pivotal connection between this link and its supporting carrier 31 or 32, and the link is located between the side walls 33. Adjacent its upper end the links 46 are each provided with an opening 49 by means of which this upper end of the link is pivotally connected to the member' 42 by the rivet 56 passing through an opening 5l in the upright portion 43 of this member. Adjacent its lower end member 43 is provided with an elongated curved opening 52 struck about the center of the opening 51 as a center. Thus the member 42 has limited movement relative to its carrier 31 and 32 by swinging movement of the link 46 about its pivotal connection 47 to the carrier, but it also has relative longitudinal movement with respect to the carrier which is permitted by the elongated opening 52 through which the rivet 5.57 extends. This movement is provided for a purpose presently to be described.
Mounted on the projecting end portions of the torque bar 23 is means for supporting the rear edge portion of the seat 11 and also the back rest associated therewith. This support includes a pair of laterally spaced rear chair seat holders 53 including wall 54 on which the seat rests and to which it may be secured by suitable screws in openings 55 in this wall. This wall connects laterally spaced upright supporting walls 56 and 57 preferably in the form of upright plates, the walls 56 extending forwardly and having openings at their forward ends through which the torque bar 23 extends and by which the plates 56 are supported on this bar. Extending transversely between and secured to these plates 56 is a tilting rear frame 58 comprising an angle member including an up right flange 59 and a forwardly extending flange 60 at its upper edge, and at its opposite ends this frame includes forwardly extending end walls 61 located at the inner sides of the plates 56 and may be secured thereto by any suitable means, such, for example, as welding. The torque bar 23 also extends through openings in these end walls 61 to provide a wider bearing support for the rear frame and rear chair seat holder on this bar. The walls 57 are provided with laterally extending flanges 62 connected to the upright flange 59 of the frame 58 by any suitable means, such, 4for example, as welding 63.
Also mounted on the tilting rear frame 58 is a rear frame support 64 comprising laterally spaced upright plates or end walls 65 and a connecting top wall 66 resting at its front end portion on top of the flange 60 of the tilting frame member 58 and secured thereto by any suitable means, such, for example, as welding 67. The upright end walls 65 are provided with laterally extending flanges 68 at their forward edges resting against the rear side of the upright wall or flange 59 of the frame member S8 and secured thereto by any suitable means such as welding 69.
The support for the back rest (not shown) but which may be the regular or suitable support or back rest for this type of chair, is supported by the transversely extending back plate 70 on suitable upright supporting bars 71 secured to the opposite ends of this plate. This plate and therefore, the back, including the back rest, are mounted on the rear frame support 64 for both tilting adjustment with respect to this support and also ad* justment up and down for height with respect to this supn port and the chair seat. For this purpose there is secured to the forward side of the plate 70 a lock plate 72, this plate 72 being secured to the plate 70 by any suitable means, such, for example, as rivets 73. The opposite ends 74 of the plate 72 are bent or olset forwardly so as to be spaced from the plate 70 to receive between these plates the upright laterally extending flanges 75 of a pair of side tilt carriers 76 which are located at the outer side of the upright wall 65 and are pivotally connected thereto by the pivot studs 77 passing through the members 76 and the walls 65. The side tilt carriers 76 are connected by the back plate support 78 extending between these members 76 at the forward side of the offset ends 74 of the plate 72, and this plate 78 is connected at its opposite end edges to the members 76 by lugs '79 extending through openings in the members 76 and riveted over to provide a rigid connection between them. Thus the plates 70 and 72 carrying the supports 7i for the back rest may be adjusted vertically or up and down on the anges of the side tilt carriers 76, and they may be locked in adjusted position by the locking bolt 8i) passing through an upright elongated slot in the plate 7S and having a head 81 at the forward side thereof, the bolt also passing through plates 72 and 70 and threaded into a hand Wheel 82 with a washer 83 between the inner end of the hub 84 of this wheel and the plate 7d. It will be clear that after adjustment of the plates 70 and 72 the back rest may be secured in adjusted positions by tightening up the locking hand wheel 82.
The side tilt carriers 76 may be shifted to different angular' positions on the `rear frame support 64 by shifting them about the pivot 77. They may be secured in different angular positions by a transverse `clamping or locking bolt 85 extending through the end walls 65 of the support, and elongated curved slots S6 in the walls '76 struck about the pivot 77 as a center. Side clamps 87 are also located yon the outer side of the walls 76 on the pivots 77, and the bolt 85 extends through these clamps. At one end the bolt includes a head 88 and Aat its opposite end it is threaded into the hub or shank of a T-handle 99. A sleeve or tube @l embraces the bolt 85 and extends between the side walls 65 of the frame support. Thus, after adjustment, by tightening up of the T-handle 99 the clamps 87 in the walls 76 are clamped oy the bolt against the side walls 65 to lock the members 76 and therefore the plate 7@ indifferent angular positions.
To control the tilting movements of the chair seat and the back `the free end of the torque bar 23 opposite the control 2.4 is bent laterally as indicated at 92 at the outer side of the side wall 56 of the seat holder 53, and its free end is secured or locked thereto by the torque bar lock 93. In the form shown this comprises a hat bar secured adjacent `one endy to the plate 56 by the bolt 94 and having a looped portion 95 embracing the free end of the laterally extending portion 92 of the bar and having the free end of this loop extending lthrough a slot in the wall 56 and "bent downwardly on the inner side thereof to form a locking flange 96 to securely secure and lock this member 93 as well as the free end of the laterally bent portion 92 of the torque bar to the member 56, and therefore to the rear chair seat holder 53 and the rear frame support 6ft carrying the back and back rest.
The seat and its support, together with the support for the back, are shown in their normal. positions in Figs. l and 2. The body member 10 and the forwardly extending carriers and supports `for the front spider arm 37 are stationary on the screw post 18, while the rear chair seat `holders 53 and the lrear frame support 64 carrying the rear edge portion of the seat and the hack restare tiltable downwardly and backwardly about vthe torque bar 23 as a pivot, and this downward movement of these members is limited by the forwardly extending flange 6@ engaging the bumpers 22. Substantially theposition of the rear edge portion of the seat 11 is indicated in Fig. 2 by the broken lines iin. During this "down ward or tilting movement the free lend `of the laterally bent end 92 of the torque bar is swung downwardly, thus placing a torsional strain on this bar which tends to return these supports 63 and 64 to their upward or normal position of Fig. 2, and therefore of course carry with them the rear edge por-tion of the chair seat and the back. Therefore, when backward tilting pressure to the chair weaver seat' and the hack is applied by. a person. sitting, in the chai-r andl'eaning backwardly, a torsional strain is placed on the torque bar, but as the person yleans forward or gets up from the chair, thus releasing the backwardly tilting pressure on. the seat and back, they are returned to the normal position by torsional' tension or stress in the torque bar. This stress may be adjusted by means of the screw 27 acting against the `arm 26 connected to the torque bar, it being increased by shifting the screw 27 baekwardly or to the right `as viewed in Fig. 2. As this bar is of `considerable length and' the movement of the free end 92'during the tilting operation is relatively small, there is very little, if" any, increase in. stress built up in the bar during the tilting movement, and therefore the stress in the bar is substantially uniform for yall positions Iof the tilting support.
lt willlbeseen from Fig, 2 that as the rear edge portion of. the chair seat is lowered or tilted downwardly, as well as the back support tilted rearwardly, the movement is on an arc about the center axis lof the torque bar Z3. Thus, as indicated in Fig, 2, the rear edge, indicated by the rear edge 97 of the. support 5d' will move on the arc 9S"struck' from the center of this bar; This will mean that this point and' therefore the4 seat during the downward tilting movement. must shift or move bodily rearward a certain amount. Therefore, the front end spider arm 37 must move rearwardly. ln other words, the rivet Sil on each supporting member 42 for the lfront'` spider arm 37' swings to the right or rearwardly with the upper. end of the link 46 about its pivotal connection i7 to the supporting arms 31 and 32. As the rivet 56 is fixed in the memher 42, this member must lalso shift to the right` or rearwardly as viewed in Fig. 2, and this movement is permitted by the elougatedopening of Vslot 52 embracing the lower. pivot rivet. 47 of the linl: t6. However, the height ofthe rivet i? above the floor varies only very slightly and therefore. this` movement does not vary the height ofthe `forward end edge. lill; of the chair seat above the l'oor. Therefore, with this construction the downward movement of the rear end portion of the chair orthe tilting movement of` the chair seat` and the back. is eiected without changing the height of the. forward edge portion of the chair seat above the hoor, so that when these parts are tilted as the users feetv can lstill maintain their normal andicomfortable position on the floor. Also during'the: tilting movements of the chair seat and back there is no vertical or up' and down relative movement between the rear' edge portion of the seat and the bach which would tend to cause d-isarrangementor untidiness of the garments `of the' user of the` chair.
An improved means for adjustingV the height ot the chair is shownLin'Figs. 7Y to 9. Any suitableor usual type ofbase or supporting legs is employed', the top or upper portion of which is partially shown at 19 provided with4 an opening in which is' seated a tubular hub 99 provided with an' enlarged hollow head portion 166 thus providing a lateraiiy'extending harige or shoulder 191 seating on the top of the base 19'. This hollow head is open at the top but is closed by a cover or closure 132 having side walls 1lb?) telescoping with the. head iti. Mounted within this tubular hub are upper. and lower bearings ldd and lilSresp'ectively'for the screw post 1h. These bearings can be atight' fit in the sleeve 99, and the upper bearing is provided with a laterally extending hangs 1lb? at its upper end restingon the oifset 101i of theitubular hub` Resting on the top of this ange 166, and therefore having a supporting thrust bearing thereon, is a nur 167 having threaded engagement with. the. screwpostl 1S, and therefore byfrotating this'nutthe height of the post in the base 191 maybe adjusted, or, more'correoti'y, if the nut is heid stationary and' the post 1-8- is rotated, the height of4 the chair seat may be adjusted. This nut is provided with an outwardly extending flange d at its lower end, and the nut has a laterally extending opening 109 in one side wall in which is mounted the stop pin lll) having its free end projecting outwardly a certain distance beyond the outer wall of the nut. This pin may be a drive or force fitV in the nut; At the opposite side of the nut it i'sprovided'witli a recess 111 extending. outwardly from the threadedopem ing through the nut, and in this recess is a steel ball 112 in back of which is a spring 113 tendingto force this ball inwardly and normally keep it seated in a longitudinally extending channel or groove 114 in one side` of the screw post 1S. This spring-pressed ball cooperating with this groove or channel provides a yieldable connection between the post 18 and the nut 137, which will normally cause the nut to rotate with the post unlessit is` held' stationary by some other means, and thus the nut will provide a supporting thrust bearing for the post and will rotatably support the post and the chairseat with its control carried thereby on the lower flange bearing' 106'and on the base 19. Whilerthe'nut is free' to turn, rotationof the chair seat and therefore the post 18 will rotate the nut and therefore permit swivel or turning movementsof the chair seat without varying the height of 'the seat.
However, means isprovided wherebythe nut may be heldstationary so that turning movements ofthe chair and therefore the post 18 may be employed to adjust the height of the chair above the base 19, and therefore, of course the iloor. For this purpose there is mounted on thebase 19 at one side ofthe head 1100 of the tubular hub a bracket 115, in this case comprising a strip of metal having its intermediate portion 116 bent to substantially inverted U shape and laterally extendingflanges forming` feet M7 resting on the top of the hat' metal ring 11'8`on top ofthe base 19, and thebracltet may besecured to this ring" by any suitable means such as the screws 119; Mounted in this bracket between the side walls` lIG1 is a slide 12h having itsinner end 1,'21 projecting through an opening ink the' side wall of the head` 100'. This slide is mounted for lateral in andy out movements in the bracket iii-'Sp ln the arrangement shown it is provided with a pair of elongated slots 122 through which are transversely'extending guidek pins 12.3. Pivoted to the outer head portion of the slide 12d at 124 is a lock finger or catch' 125' having a downwardly extending'lug` 126 at its fiee end' adapted to seat in an opening-12"] in the top wall of the bracket 11S to hold the slide` 1251*n in the normal position shown in Fig; 7`, which is an intermediateposition for' this slide, with its inner end 121 overlapping the top of the flange idd on the nut 167, as shown; ln this position this slide cooperates with this flange to prevent' the nut 167E being lifted off its bearing support 196; Therefore, this provides a connection between the chairseat andthebase to prevent lifting the chair seat from the base.
The catch-125 has an overhanging finger grip 123' at its free end by which it may be lifted to remove the lug- 1`2from the opening lli. This will release the slide12il and permit it to be shifted either inwardly or outwardly from the position shown in Fig. 7. if it is shifted outwardly, or to the right as viewedin this gure, this mover ment will shift its inner end 121` away from its overhanging position with respect to the illange idd on the nut ldi'J and therefore will release it and permit lifting. of the chair seat and the supporting control carried by the post i8, separating them from theA base 19: If the slide 12d is shifted inwardly from the position of Fig, 7`, its inner end 121 may be shifted inwardly beyond the- 'free end of the stoppin 110; Then if the chair seat' andthe post it are rotated, this pin 11d wiliengage the inner end 121 of the slide and hold the nut lii against rotation. Then the spring-pressed ball 1.12 will yield and permit the chair seat and the post. 1S to be rotated withrespectttor this. stationary held nut and. adjust thel height. of the` chair seat. either upwardly on downwardly, as.` desired. After theY proper adjustment has been secured; shifting; of the slide 12h` back to its intermediate position will release the nut 107 and prevent relative turning movement between the post and this nut, and prevent further adjustment. Slide 12?, however, being in this position, with answer its inner end overlianging the llange MP8, will prevent separation of the nut post and therefore the chair seat from the base; This provides a simple and effective means for connecting the chair seat to the base, and one which may be readily manipulated with a simple operation to permit adjustment of the height of the chair seat, and then after the proper adjustment has been secured, may be easily reset to permit swivelling or" the chair seat without causing height adjustment, and at the same time will secure the post and the seat and other construction carried thereby to the base.
'Having thus set forth the nature of my invention, I claim:
l. In a chair control of the character described, an elongated transversely extending body member, a supporting post on which the body is mounted, supporting arms extending forwardly from the body, a transversely extending seat supporting spider arm at the forward ends of said supporting arms, means mounting the spider arm on the supporting arms for forward and back horizontal movement as well as pivotal movement, a longitudinally extending torque bar mounted in the body member, a rearwardly extending chair seat holder pivotally mounted on the body for Vbackward tilting movement, a back rest support mounted on said holder, means holding one end of the torque bar stationary, the other end of the torque bar being bent laterally forming a laterally extending arm, and means anchoring said latter arm to the rear chair seat holder to place torque stress on the bar as the holder is tilted backwardly.
2. In a chair control of the character described, an elongated transversely extending body member including upright end walls, a support for the body, supporting arms extending forwardly from the body, a transversely extending seat supporting spider arm at the forward ends of said arms, upright links pivotally connected to said spider arm and the supporting arms mounting the spider arm on the supporting arms for pivotal movement and horizontal back and forth movement, a longitudinally extending torque bar in the body and mounted in said end walls, Va rearwardly extending chair seat holder pivotally mounted on said bar for backward tilting movement, means holding one end of the torque bar stationary, the other end of this bar including a laterally extending arm, and means locking lthis latter arm to the rear chair seat holder to place torque stress on the bar as the holder is tilted backwardly.
3. In a chair control of the character described, an elongated transversely extending body member, forwardly extending supporting arms on the body, a chair seat above the body, pivotal means connecting the front edge portion of the seat to said arms for back and forth horizontalrv movement, a rearwardly extending chair seat support for the rear edge portion of the seat pivotally connected to the body for rearward and downward tilting movement, and resilient means on the body connected to the rearwardly extending seat support to resist said tilting movement.
4. In a chair control of the character described, a body member, a chair seat, means mounting the forward edge portion of the seat on the body for pivotal as Well as horizontal forward and backward movement, a support for the rear edge portion `of the seat pivotally connected to the body for up and down tilting movement, and resilient means on the body connected to the rear seat support and resisting downward tilting movement of said support.
5. In a chair control of the character described, a body member, a chair seat, means mounting the forward edge portion of the seat on the body for pivotal as well as horizontal forward and backward movement, a support for the rear edge portion of the seat pivotally connected to the body for up and down tilting movement, a longitudinally extending torque bar mounted in the body, means holding one end of the bar stationary, a laterally extending arm at the other end of the bar, and means locking said arm to the rear seat support to place torque stress on the bar by downward tilting movement of said support.
6. `In a chair control of the character described, an elongated transversely extending body member including upright end walls, a support for the body, supporting arms extending forwardly from the body, a chair seat, downwardly extending support members for the front edge portion of the seat, means pivotally connecting said supporting members to the forward ends of said arms and permitting back and forth horizontal movement of these members on the arms, a support for the rear edge portion of the seat pivotally mounted on and extending backwardly from the body for up and down tilting movement, and yieldable resilient means mounted on the body and connected to said rear support to resist said tilting movement.
7. :ln a chair control of the character described, an elongated transversely extending body member including upright end walls, a support for the body, supporting arms extending forwardly from the body, a chair seat, downwardly extending supporting members for the front edge portion of the seat, upright links pivotally connected at their opposite ends to the supporting members and the supporting arms, a support for the rear edge portion oi the seat pivotally mounted on and extending backwardly from the body for up and down tilting movement, a longitudinally extending torque bar mounted in said end walls, means holding one end of the bar against turning, a laterally extending arm at the other end of the bar, and means locking said arm to the rear seat support to place a torque stress on the bar by downward tilting movement of said support.
8. In a chair control of the character described, a transversely extending body member, a support for the body member, supporting arms extending forwardly from the body, a chair seat, downwardly extending supporting members for the front edge portion of the seat, upright links pivotally connected lat their opposite ends to said supporting members and said arms to permit forward and backward movement of the seat, a support for the rear edge portion of the seat pivotally mounted on and extending backwardly from the body for up and down tilting movement, and yieldable resilient means resisting said tilting movement.
9. In a chair control of the character described, a transversely extending `body member, a support for the body member, supporting arms extending forwardly from the body, a chair seat, downwardly extending supporting members for the front edge portion of the seat, upright links, pivot means connecting the upper ends of the links to said supporting members and the lower ends of said links to the supporting arms, said supporting members being provided with longitudinally extending elongated slots embracing said lower pivot means permitting backward movement of the seat, a support for the rear edge portion of the seat pivotally mounted on and extending rearwardly from the body for up and down tilting movement, and yieldable resilient means resisting downwardly tilting movements. y
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|U.S. Classification||297/300.4, 297/303.3, 248/608, 248/575, 297/300.7, 297/354.1|
|International Classification||A47C3/026, A47C3/02|