US2760553A - Tilting chair - Google Patents

Description

Aug. 28, 1956 F. LIE 2,760,553

TILTING CHAIR Filed June 7, 954 2 SheetsSheet 1 Aug. 28, 1956 F. LIE 2,760,553

TILTING CHAIR Filed June 7, 1954 2 Sheets-Sheet 2 IN V EN TOR.

FINN L BY 5 M/ TH, 0155/MA0U5 '4 TTORNEVS United States Patent-"O TILTING CHAIR Finn Lie, Ring Station, Norway Application June 7, 1954, Serial No. 434,863

4 Claims. (Cl. 155-77) This invention relates to a tiltable chair construction and particularly to a mechanism for permitting tiltable movement of a chair seat and for causing the build up of a resilient restraining force in opposition to the tiltable movement thereof.

Generally tiltable chairs are provided with mechanism of one kind or another for subjecting the chair seat to a resilient force in opposition to any force which the user might put thereon as the chair was tilted. The theory is that unless a restraining force is provided to oppose tilting movement of the chair the user will almost assuredly jolt or otherwise upset himself as he shifts his weight to or from the back of the chair at the times when he is leaning backward or forward in the chair seat. The provision of a restraining force serves to soften or cushion the tilting action so that the user will not receive a jolt or otherwise upset himself on cessation .of the tilting movement. Of course for these softening or cushioning mechanisms to be fully effective an adjustment must be provided for varying the restraining force, it being appreciated that a relatively heavy person would impose a relatively heavy force on the chair seat that would require a relatively strong resilient restraining force whereas a relatively light person would impose a lighter force on the chair seat that would require a relatively weak restraining force.

In my application for patent, Serial No. 395,392, filed on December 1, 1953, now Patent No. 2,718,257, granted September 20, 1955, there is disclosed a mechanism for permitting tiltable movement of a chair seat and for causing the build up of a desired resilient restraining force in opposition to the tiltable movement thereof, wherein the resilient restraining force is provided by a torsion bar extending along the axis about which the chair moves in its tiltable movement. The present invention is an improvement on the invention disclosed in the aforementioned application and also utilizes a torsion bar "to'provide the desired restraining force.

It is an object of the present invention to provide a mechanism having the aforementioned function wherein the elements or devices which are employed for mounting the torsion bar are of simplified construction, thereby permitting production of the mechanism at a cost competitive with that of prior art mechanism.

It is another object to provide a mechanism having the aforementioned function wherein a single element is employed for accomplishing the dual function of mounting the chair seat for tiltable movement and limiting said tiltable movement.

It is another object to employ with a mechanism of the aforementioned character a device for manually adjusting the amount of restraining force which it is desired to impart to a tiltable chair, wherein said adjusting device embodies two threaded elements so related to each other that one element will not bind or otherwise tend to prevent movement of the other threaded element upon the application of a manual force thereto.

Other objects of this invention will appear in the fol- .lowing description and appended claims, reference being had to the accompanying drawings, forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

Figure 1 isv an elevational view of a chair having incorporated therewith a control mechanism constructed according to the teachings of the present invention.

Figure 2 is a view of the control mechanism taken on line 2-2 in Figure 1.

Figure 3 is a sectional view taken on line 33 in Figure 2.

Figure 4 is a view taken in the direction of line 4-4 in Figure 3.

Figure 5 is a sectional view taken on line Figure 3.

Figure 6 is a sectional view taken on line 66 in Figure 3.

Figure 7 is a view taken on line 7-7 in Figure 3.

Figure 8 is a view taken on line 8-8 in Figure 4.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring more specifically to the drawings the construction there illustrated will be seen to include a support in the form of a cylindrical post 1 adapted to be rotatably mounted in a floor-engaging base 50.

Secured on the upper end of post 1 is a hollow arm or tube 2. As can be seen in Figure 2 tube 2 is provided with a circular opening 3 to provide a surface 5 forengagement with shoulder 6 formed by reduced portion 7 on post 1. Tube 2 is provided with a central portion 8 and end portion 9. Left end portion 9, as seen in Figure 3, is thickened internally at 13, to provide a non-circular recess 10 for non-rotatably receiving one end ofa non-circular torsion bar 11. The recess and bar are shown as of square shape but they may be of other non-circular shapes.

Rotatably encircling tube 2 is a sleeve-like cross piece 25 having its ends anchored on bracket arms 27 and 28 which are adapted to be'secured on the underside of the chair seat 51. In view of their functions arms 27 and 28 may be considered as seat mounting members. Cross piece 25 provides a firm, non-twistable connection between arms' 27 and 28. The result is that when a strain is placed on the chair seat each of members 27 and 28 will take its proportionate share of the load and one memher will not twist relative to the other.

It will be seen from Figures 2 and 6 that sleeve 25 is provided with an elongated opening 32 having its major diameter extending transverse to the sleeve. Opening 32 permits limited rotational movement of sleeve 25 on tube 2.

Referring once again to torsion bar 11, said bar extends loosely through a circular opening 12 formed in post 1. The right end of said torsion bar (as seen in Figure 3) is non-rotatably received in enlarged hub portion 14 of lever 15, the free end of which is apertured at 16 for non-rotatably receiving a nut 18. As seen in Figures 4 and 8 the nut 18 is formed with arcuate shoulders 19 for engagement with surfaces 20 of lever 15. A screw 21, having knob 22, is extended through one flange of member 28 and into threaded engagement with nut 18. Lever 15, screw 21 and nut 18 form a manually adjustable connector means between bar 11 and member 28. It will be appreciated that by an appropriate turning of knob 22 screw 21 will be rotated, thus causing lever 15 to turn in the direction of arrow B in Figure 4,

and twist bar 1 around its axis. The amount of twist which turning of knob 22 will impart to torsion bar II will determine the magnitude of the restraining force which isavailable to resist tilting of the chair. v

The arcuat'e shape of shoulders-19 permits them to rock on surfaces 20 and thus tends to prevent screw 21 from binding in nut 18 as lever is pivoted around the axis of bar 11 by turning, movement of knob 22. In other words having in mind that as lever 15 (in Figure 4) is broughtcloser, for instance, to the horizontal flange of member. 28 there will be a slight swinging movement of screw 21 away from bar 11, resulting in a change of position of shoulders 19 with respect to surfaces 20, it will be appreciated that if shoulders I9 were flat they would engage surface 20 at their endportions and there would be a tendency of nut 13 to tip or cant with respect to screw 21 and set up a binding. action between the threads thereof. Since however shoulders I? are arcuately shaped they will always engage surfaces 20 at or near a point intermediate their end portions and there will be little tendency for the nut to tip and set up a binding action between threads.

With. the arrangement of parts as shown in Figure 3, end portion 35 of angle member 28 will be disposed. beneath the rear portion of the chair seat and end portion 36 of angle member 28 will be disposed beneath the front portion of the chair seat. When the occupant of the chair leans back inthe chair, end portion 35 will tip downwardly about the longitudinal axis of torsion bar 11 and cause said bar to twist. in the direction of arrow B. As before stated the amount of twist in bar 11 can be varied by an appropriate turning. of. knob 22.

An advantage of the instant embodiment, insofar as simplicity oi construction is. concerned, resides in the fact that a single sleeve-like cross piece is employed for bothv mounting the chair seat for rotatable movement around tube 2 and for limiting. said rotatable movement.

Another advantage resident in. the instant embodiment stems from the fact that manual adjustment of the position of torsion bar 11 can be achieved by an easy turning movement of knob 22 without the occurrence of binding forcesbetween nut 18 and screw 21.

Having thus described the invention, I claim:

1. In a chair having seat mounted for limited tilting movement about a "horizontal axis the combination comprising an upright post, a generally horizontal tube centrally and fixedly mounted on. the upper end. of said post, a torsion bar within said tube and having one of its ends anchored at one end of said tube, two spaced seat mounting members, carrying said. seat, a sleeve encircling saidtube and having its ends anchored to said seat mounting members, said sleeve having an opening therein in registry with said post, said opening being longer in a direction transverse to the sleeve than the corresponding dimension of said post for permitting said sleeve to rotate a limited amount around said tube, and means connecting the other end of said torsion bar with one of said seat mounting members whereby as the chair seat is tilted around the axis of said torsion bar the bar will twist and exert a resilient restraining force against further tilting of the chair seat.

2. In a chair as claimed in claim 1 and further characterized in that the means connecting the other end of said torsion bar with one of said seat mounting members comprises a manually adjustable connector for imparting an initial twist to the bar with respect to said seat mounting members to thereby provide a desired preloading of the bar and exert a controlled restraining force on said seat member when it is tilted around the axis of said bar.

3. In a tiltable chair construction the combination comprising twospaced seat mounting members; a support, an arm fixedly mounted on said support to extend laterally thereof; a torsion bar extending along said arm and having one of its ends anchored at one end of said arm; a cross piece extending along said arm and rotatably mounted thereon with its ends anchored to the spaced seat mounting members, said cross piece having means in registry with. said support to limit the rotatable movement. thereof; and means anchoring the other end of said torsion bar on one of said seat mounting members; said anchoring means comprising a manually adjustable connector for changing. the position of the bars said other end with respect to said seat mounting member to thereby provide the desired cushioning force when said seat mounting. member is tilted around the axis of said bar.

4. The combination according to claim 3 wherein said manually adjustable connector includes a lever extending from the said other end of. the torsion bar; screw means between. said lever and the adjacent seat mounting member; and a nut in. threaded engagement with said screw means for causing, arcuate movement of the lever around the axis of said. torsion bar in response to rotational movement of said screw means; said nut having an armate shoulder inengagement. with said lever for prevention of binding between the threads of said nut and screw 7 means.

References Cited. in the file of this patent UNITED STATES PATENTS 2,016,753 Patzig Oct. 8, 1935 2,075,041 Kliesrath Mar. 30, 1937 2,633,897 Moore Apr. 7, 1953 FOREIGN PATENTS 246,541 Switzerland Oct. 16, 1947 675,688 Germany May 13, 1939

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