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Publication numberUS3162420 A
Publication typeGrant
Publication dateDec 22, 1964
Filing dateAug 17, 1961
Priority dateAug 17, 1961
Also published asCA737269A
Publication numberUS 3162420 A, US 3162420A, US-A-3162420, US3162420 A, US3162420A
InventorsLie Finn
Original AssigneeLie Finn
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Torsion bar chair iron
US 3162420 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

Dec. 22, 1964 F. LIE 3,162,420

TORSION BAR CHAIR IRON Filed Aug. 17, 1961 2 Sheets-Sheet 1 #60 INVENTOR.

F/NN L/E BY "ML o/w SETTLE & CRAIG Dec. 22, 1964 F. LIE

TORSION BAR CHAIR IRON Filed Aug. 17, 961

2 Sheets-Sheet 2 INVENTOR. FINN LIE.

BY MLso/v, SETTLE & Came United States Patent Ofifice 3,162,420 Patented Dec. 22, 1964 s,re2,42e TGRSIUN BAR CHAIR IRGN Finn Lie, Ring Station, near Harnar, Norway Filed Aug. 17, 1961, Ser. No. 132,037 6 Claims. (Cl. 248-373) This invention. relates to chair irons for tilting chairs, as for example office chairs, and more particularly this invention relates to a tiltable chair iron wherein a simplified torsion bar construction is utilized to resiliently restrain the backward tilting of a chair seat and back as a person, sitting in the chair, shifts his weight to tilt the seat and back in a rearward manner, and wherein the chair seat absorbs the torque of the torsion bar.

A number of tilting chair iron constructions have heretofore been developed which comprise as a part of their mechanism, telescopic tubes which rotate relative to each other, and also a torsion bar within the inner telescopic tube to provide a resilient restraining force against movement of a chair seat. While the telescopic tube structure provide tilting chair mechanisms of substantial durability and long life, their costs of manufacture are increased by the necessary telescopic tubes and the labor involved in assembly and joining these parts.

In addition to the steps forward in the art provided by the telescopic tube torsion bar assemblies over the prior art chair iron constructions utilizing heavy castings and coil springs, a further advance in the seating art would be provided if the telescopic tubes of torsion bar structures could be eliminated, thereby further simplifying the structure and reducing the cost of manufacture of tilting chair iron constructions.

Accordingly it is an important object of the present invention to provide a novel, tiltable chair iron utilizing a torsion bar to provide a resilient restraining force for the tilting movement of the chair seat, as a neat, precise and compact unit of simplified construction.

Another object is to provide a tiltable chair iron, utilizing the torsion bar principle, which is of improved, simplified construction and is readily assembled with a minimum amount of labor, and that has long life substantially free of maintenance.

A further object is to provide a tiltable chair iron utilizing a torsion bar wherein the chair seat frame absorbs the torque from the torsion bar.

A further object is to provide a tiltable chair iron utilizing a torsion bar wherein a chair seat frame bracket engages spaced stop members carried by a torsion bar support tube bracket to establish the limits of pivotal movement of the chair seat.

A still further object is to provide a tiltable chair iron utilizing the torsion bar principle wherein a simple tensioning arm of neat appearance is interposed between one end of the torsion bar and a chair seat frame bracket to provide adjustment of the tension of the torsion bar and thereby adapt the chair to use by occupants of differing Weights.

A still further object is to provide a tiltable chair iron using a torsion bar without the requirement of telescopic tubes in its structure as heretofore used, thus providing a novel tiltable chair iron construction of simplified configuration and of substantially lower cost.

Other objects of this invention will appear in the following 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 is a front elevational view of a chair incorporating a novel, tilting iron of the torsion bar type, made in accordance with the present invention;

FIGURE 2 is a top plan view of the novel torsion bar, tilting chair iron of the present invention;

FIGURE 3 is a left end elevational view taken along the line 33 of FIGURE 2, looking in the direction of the arrows;

FIGURE 4 is a right end elevational view taken along the line 4-4 of FIGURE 2, looking in the direction of the arrows;

FIGURE 5 is an enlarged fragmentary top plan view of the right hand end of the support tube, showing the assembly of the stop-carrying bracket thereto;

FIGURE 6 is an end elevational view taken along the line 6-6 of FIGURE 5 FIGURE 7 is an enlarged fragmentary exploded top plan View showing the manner in which the right hand seat frame bracket is mounted for pivotal movement Within the right hand end of the support tube;

FIGURE 8 is an enlarged right end elevational view taken along the line 88 of FIGURE 7, and looking in the direction of the arrows; and

FIGURE 9 is an enlarged fragmentary exploded top plan view showing the assembly of the right hand endof the iron of FIGURE 2, with the torsion bar Within the support tube and extending through the right hand seat frame bracket to connect with the adjusting lever.

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.

Brief Perspective Briefly the present invention relates to a novel tilting chair iron of the torsion bar type wherein a main support tube pivotally supports a pair of chair seat frame brackets. A torsion bar is positioned within the support tube and is connected at one end to the support tube. The torsion bar extends out of the other end of the support tube for connection to one end of an adjusting handle that is restrainingly engageable at the other end to one of the chair seat frame brackets.

In accordance with this simplified and improved structure of the present invention, the chair seat frame absorbs the torque from the torsion bar.

A yoke of simplified configuration is joined to the support tube intermediate its length and is provided with a spindle hole to receive the upper end of the spindle provided in a chair base, whereby the iron and the seat carried thereby are supported for pivotal movement upon a chair base.

Thus, pivoting of the chair seat about the support tube is resiliently restrained by the torsion bar; the chair seat frame absorbs the restraining force of the torsion bar; and the seat is restrained within limits of pivotal movement by engagement of one of the seat frame brackets with stops carried by the support tube of the iron.

The Environment As shown in FIGURE 1, a chair structure utilizing a torsion bar iron of the present invention includes a floorengaging base it) having outwardly extending legs 12 supported at their lower terminal ends by rollers 14 for moving the chair over a supporting surface. Centrally of the base 10 there is provided a vertically disposed spindle 16 having an exposed upper end, suitably of tapered configuration (not shown). The upper end of the spindle 16 projects into a spindle hole 18, FIGURE 2, formed in bight portion 32.

be still further reduced;

a yoke 20 that supports the chair iron 22 of the present invention. A chair seat 24, FIGURE 1, is mounted upon the iron 22 for rearward pivotal movement against re-' siliently restraining forces imparted by a torsion bar, to be. subsequently described, which forms acomponent part of the iron. Chair arms 26 and a back 28 of suitable configuration are mounted on the seat 24 in a conventional manner tocomplete the chair structure.

The Novel Iron As shown in FIGURE 2, the chair iron structure cencent each of the ends for attachment of the chair seat frame by bolts or the like as previously mentioned. At the ters around a support tube 30 that is secured to and 7 carried by the aforementioned yoke 2d. The yoke 20 is suitably made of a stamping of generally U-shaped configuration, having a bight portion 32 to the ends of which mentioned spindle hole 18 is formed centrally of the The upstanding arms 34 of the yokefltl are provided with aligned apertures through which the support tube 3% is inserted and then the parts are suitablyjoined as by welding as at 36. It will be noted that the yoke 20 is positioned centrally of the support tube 30 so thatthe weight of the chair above the iron 22' will be equally balanced on each side of'the spindle hole 18 when th spindle 1 6 is inserted therein.

V The frame of the chair seat is pivotally mounted upon the support tube 30 by connection at the 'left end to a bracket 38 and at the right end to a bracket 40. As shown in the end elevational view of FIGURE 3, the

bracket 38 comprises a vertically disposed wall 42 of triangular configuration with the base of the triangle in of the support tube 30 is inserted into the bearing 48 and thus the bracket 38 is rotatably mounted upon the left end of the tube 30. A small amount oflubricant is applied between the bearing 38 and tube 30 to facilitate rotation and provide long life.

As best shown in FIGURE 5, the right end of the support tube 30 is fitted with a stop bracket arm 50.] As

shown in the FIGURE 6, the bracket arm 50 is provided are integrally joined upstanding arms 34. The previously 'the form of a horizontally disposed elongated plate 44. It will be seen from, the foregoing description that the' intermediate'its length wit-h an aperture 52 into which e the righthand end of'the'support tube 30 is fitted, followed by fastening as for; example by welding as at 54. The Stop Members V Adjacentthe front end of the stop bracket arm 50,

there is provideda front stop member 56 that, as'shown, I

may be a separate piece of steel welded as at SS'. Also, at the rear end of the stop bracket arm 50, there is provided atrear stop member 60 that may be a separate piece, also welded as at' 62. In connection with the front and rear stop members 56 and 60, it is to be considered within the scope of the invention to punch them out of the body 7 B of the stop bracket arm 50, as will be evident to those skilled in the artof metal working. 7 By so operating, the labor involved infabricating, the present invention would As shown in FIGURES7 and 8, the right hand chair frame support bracket 40 is generally similar in configuration'to the left hand chair seat frame bracket 38 and includes a generally triangular vertically disposed wall 64 integrally formed with an elongated and horizontallydisrestrained by torsion bar 74 restraining the tension-adjustlower apex of the triangular verticalwall 64, an aperture 68 is provided and a tubular bushing 74 is inserted and fixed in position as by welding at '72. The outside diameter of the bushing 78 is slightly smaller than the inside diameter of the support tube 36, FIGURE 7, so that the two parts may interfit in rotatable relation, a small amount of lubricant being applied during assembly to facilitate rotation and provide long life.

'By reference to the, assembled view of FIGURE 4, it will be'noted that the right hand seat frame bracket 40 is restrained, in its forward movement by abutment with the front stop member 56 of stop bracket arm 50 and is restrained in its rearward pivotal movement by engagement with the rear stop member 60 of stopbracket arm 50. I f i The T orsio n Bar V By reference to FIGURES 3, '4 and 9 of the drawings, it will be observed that a torsion bar 74 extends coaxially of the support tube 30. At the left end of the chair iron 22, the torsion bar is secured to the support tube 30. This is done by fitting onto the torsion bar, an annular plug 76 that is provided with a centrally disposed square hole for receiving the left end of the torsion bar 74; fasteningthe plug to the torsion bar as by welding; and also fastening the outer periphery of the plug to the inside wall of the support tube 30 as by welding. Thus the left end of the torsion bar cannot move with respect to the support tube 30. 7

As shown in FIGURE 9, the right end of the torsion bar extends beyond the stop bracket arm 50 and fits freely through the inner bore of the tubular bushing 70 of right hand seat frame bracket 40. A tension adjusting and contact arm 78 is connected to the right hand end of the torsion bar 74 and is adapted to engage the underside of the horizontal plate 66 of I the right hand seat frame bracket 40. The control arm 78 is provided at its for.- ward end with a bushing 80 having an outside diameter slightly less than the inside diameter of the tubular bushing 7t) of the bracket 40. The; inside of the bushing 80 is provided with a squarebore '82 into which the extreme right end of the torsion bar '74 is adapted to fit in snugly engaging relation. A set screw 84 is provided to secure in assembled relationship, on the right hand end of the unit. The chair seat frame keeps the other bracket 38 in its properly assembled relationship on the unit. Lubricant is applied to the outside of bushing 80. V

The other end of the control arm" 78 is provided with a threaded aperture 87. An adjusting handle 88, FIG- URE 4, has a threaded portion and the threaded portion is passed through the aperture 87 so that the end of thehandle 88 passed through the aperture contacts the underside of the. horizontal plate 66 of bracket 40.

By reference to FIGURE-4 it will be observed that the chair seat would be in a.ho'rizontal'positi,on. However, J

when the chair seat is tilted backwardly, it is resiliently ing and contact arm 78 against counterclockwise rotation. Thus aresilient, restraining force is imposed against rearward-pivotal movement of the chair seat 24 of the chair ofFIGURE land the pivotal-movementof the chair seat is stopped by abutment of therearedge of the vertical.

walls- 64 of'bracketi lll with the rear stop member 60 of stop bracketarmfit). V

Tension Adjustment BY m ans of the tension-adjusting and contact arm 78, V 1 the resilient restraining, force providedf'by the torsion bar '74can be adjusted. Thus, as shown in FIGURE 4, turning the adjusting handle 38 to move-the rear" end of the contact arm 78 toward the horizontal plate 66 will have the effect of reducing the pro-twist imparted to the torsion bar 74 and thus will permit the chair to be tilted with less weight or force. On the other hand, adjusting the handle 88 to pull the rear end of the tension arm 78 downwardly and away from the plate 66 will serve to impart a greater pre-twist to the torsion bar 78 and accordingly a larger weight or force will be required to move the chair seat downwardly in a rearward tilting manner. Thus the iron adapts the chair of which it forms a component part to be used by persons of dilfering weight.

Extended Scope Materials of construction which can be used in fabricating the chair iron of the present invention generally include steel, brass, aluminum and similar metals, adapted to be fabricated with sufiicient strength into relatively light weight structures.

Although not shown, the bearing 48 supporting the left hand bracket 38 and the bushing 70 carried by the right hand bracket 40 can be lined with nylon or other selflubricating bearing material so that no extraneous lubricant need be used for the unit during its lifetime. In the construction described, maintenance is limited to the insertion of a few drops of lubricant between the inside of the bearing 48 and the outside of the left end of the tube 30 and the inside of the right end of the tube 30 and the outside of the tubular bushing 70. Similarly, a small amount of lubricant is placed between the bushing 80 of the adjusting handle 78 and the inside of the bushing 70.

Although the support tube 30 has been described above as a tube, it will be obvious that equivalent support structures can be employed within the broad scope of the invention. Thus a hollow support member of box, hexagonal or other cross sectional form could be employed. When so operating, it will be necessary to fit a bushing around the left end of the tube 30 to operate within the bearing member 48 and to fit a suitable bushing inside the right hand end of tube 30 to receive the bushing 70 of right hand chair frame support bracket 40.

Advantages of the Present Invention From the foregoing, it will be observed that a novel and improved tilting chair iron of the torsion bar type is provided in accordance with the present invention that utilizes a minimum number of sirnpiy fabricated parts. The unit is distinguished by long life, ready fabrication with a minimum amount of labor and by the fact that the chair seat frame absorbs the torque of the torsion bar.

The unit of the present invention is readily adapted to mass production methods and its assembly merely comprises the insertion of the tubular bushing 70 of the right hand bracket 40 over the right hand end of the torsion bar 74 and into the support tube 3! followed by application of the tension and adjusting control arm 78 to the right end of the torsion bar 74, followed by tightening of the set screw 84.

The unit is then suitably inverted upon an inverted seat cushion and the right and left brackets are secured to the frame of the cushion. Thereafter, the unit is inverted and placed upon the upper end of the spindle 16 of the chair base 10. Following this simple procedure, the chairs may be packaged and are ready for shipment.

I claim:

1. In a tilting chair iron, a spindle engaging yoke, a support tube fixedly carried by said yoke and having first and second ends, a stop bracket arm fixed on the first end of said support tube, first and second spaced stop members on said stop bracket arm, a torsion bar within said support tube and having first and second ends with the second end connected to said support tube at its second end, a first chair seat frame bracket rotatably journaled on the first end of said support tube, a second chair seat frame bracket rotatably journaled on the second end of said support tube, said torsion bar having its first end extended through said first chair seat frame bracket in freely rotatable relation, and a tension arm connected at its one first end to the second end of said torsion bar to retain said first chair seat frame bracket on said support tube and having its second end abutting said first chair seat frame bracket.

2. In a tilting chair iron, a generally U-shaped support yoke having a spindle socket adapted to fit upon the spindle of the base of a chair, a hollow, elongated sup port member having first and second ends and fixedly carried by said yoke, a bracket on the first end of said support member, protruding stop members on said bracket, a torsion bar Within said support member and having first and second ends with the second end fixedly connected to said support member adjacent the second end of said support member, a first chair seat frame bracket pivotally mounted within the first end of said support member to alternately contact said protruding stop members in its pivotal movement, a second chair seat frame bracket pivotally mounted adjacent the second end of said hollow, elongated support member, said torsion bar having its first end extending through said first chair seat frame bracket in freely rotatable relationship, a tension arm having a bushing journaled in said first chair seat frame bracket and fixedly connected to the end of said torsion bar to hold said first chair seat frame bracket on said first end of said support member adjacent said bracket, and the other end of said tension arm abutting said first chair seat frame bracket, whereby a chair seat mounted upon said chair seat frame bracket is resiliently restrained against pivotal movement by said torsion bar and the degree of pivotal movement is established by said protruding stop members.

3. In a tilting chair iron, a generally U-shaped yoke having a bight portion and aligned arms, said bight portion having a spindle socket adapted to fit upon the spindle of the base of a chair, a support tube fixedly carried by the arms of said yoke and having first and second ends, a stop bracket arm fixedly secured on the first end of said support tube, two spaced stop members on said bracket arm, a torsion bar within said support tube and having first and second ends with the second end fixedly connected to the second end of said support tube, a first chair seat frame bracket having a bushing rotatably journaled within the first end of said support tube adjacent said stop bracket arm to alternately contact said stop members, a second chair seat frame bracket rotatably journaled on the second end of said support tube, said torsion bar having its first end extended through said first chair seat frame bracket bushing in freely rotatable relation, a tension arm having a bushing on one end journaled Within said first chair seat bushing, said torsion bar fitting within said tension arm bushing in non-rotatable relation, means releasably anchoring said tension arm to said torsion bar, and an adjusting handle having a portion threaded through the second end of said tension arm and engageable with said first chair seat frame bracket, whereby a chair seat mounted upon said chair seat frame bracket is resiliently restrained against pivotal movement by said torsion bar, the tension of said torsion bar is adjusted by said adjusting handle, and the degree of pivotal movement of the seat is established by said stop members.

4. In a tilting chair iron, a hollow, elongated support member having first and second ends, means for mounting said support member to a chair base, a stop bracket fixed on the first end of said support member, first and second spaced stop members on said stop bracket arm, a torsion bar having first and second ends and being partially positioned within said elongated support member and having the second end connected to the second end of said support member, a first chair seat frame bracket rotatably journaled within the first end of said hollow, elongated support member, a second chair seat frame bracket rotatably journaled on the second end of 7 said hollow, elongated support member, said torsion bar having its first end extending through said first chair seat frame bracket in freely rotatablefrelation, a tensioning arm connected at one end to said first end of said torsion bar and having its other end abutting a rear portion of said first chair seat frame bracket, and adjusting means on said tensioning arm adapted to space the other end of said tensioning arm with respect to said first chair seat frame bracket, whereby a desired degree of pre-twist can be imparted to said torsion bar.

5. In a tilting chair iron, a spindle yoke, a tube non-rotatably carried by said yoke and having first and second ends, 7 a a stop bracket arm secured on. the first end of said tube,. a first and second spaced stop' members on said stop bracket arm, I a torsion bar Within said tube with first and second ends andwith the second end connected to the second end of said support tube, V a first chair seat frame bracket rotatably journaled on the first end of said support tube and alternately engageable with said first and second spaced stop members, a second chair seat frame bracket rotatably journaled on the second end of said support tube, said torsion bar having its first end extended through said first seat frame bracket in freely rotatable relation and exposed therebeyond, and a tension arm connected at one'end to the first end of said torsion bar to retain said first chair seat frame bracket on said support tube and having adjustable means connected to its other end to abut said first chair seat-frame bracket, r e Y e ,6. Inatilting chair iron, 7 g 1 a hollow elongated support member second ends, A means mounting said support member to a chair base, a stop bracket fixed on the first end of said support 7, member and provided with two spaced ahutments, V a first chair seat frame bracket rotatably journaledon the first end of said support member and alternately engageable with said two spaced abutments,

a second chair seat frame bracket rotatably journaled on the second end of said support member,

having first and a torsion bar within saidho-llow support member and ReferencesCited in the file of this patent UNITED STATES PATENTS

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2845991 *Apr 28, 1955Aug 5, 1958Manton Ahlberg HChair control or iron
US2935119 *Apr 1, 1957May 3, 1960Finn LieTilting chair restraining mechanism
US2971569 *Aug 16, 1956Feb 14, 1961Bassick CoTiltable office chair
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3284133 *Aug 27, 1964Nov 8, 1966Werner Per GunnarDevice for pivoted connection of two parts
US3403882 *Nov 14, 1966Oct 1, 1968Grythyttans Stalmoebler AbInclinable rocking chair
US3464663 *Dec 1, 1967Sep 2, 1969Blomborgs Mekaniska AbTilting chair
US3480249 *Dec 11, 1967Nov 25, 1969Lie FinnTilting chair construction
US3544159 *May 10, 1968Dec 1, 1970Consolidated Burris Intern LtdTiltable chair construction
US3598354 *Aug 27, 1969Aug 10, 1971Stewart Warner CorpChair control structure
US3788586 *Dec 12, 1969Jan 29, 1974Steelcase IncTorsion rod chair iron
US4235408 *Feb 27, 1978Nov 25, 1980Knoll International, Inc.Swivel-chair frame
US4605334 *Nov 17, 1983Aug 12, 1986Ari Associates, Inc.Linkage mechanism for coupling two movable members
Classifications
U.S. Classification248/592, 248/575, 248/608, 248/587
International ClassificationA47C7/44, A47C3/026
Cooperative ClassificationA47C7/44, A47C3/026
European ClassificationA47C7/44, A47C3/026