US3220688A - Tilt and swivel mechanism for chairs - Google Patents

Description

' Nov. 30, 1965 w. P. BAERMANN 3,220,688

TILT AND SWIVEL MECHANISM FOR CHAIRS Filed Aug. 21, 1965 4 Sheets-Sheet 1 INVENTOR:

WALTE R P. BAERMAHN M & M

Nov. 30, 1965 w. P. BAERMANN 3,220,688

TILT AND SWIVEL MECHANISM FOR CHAIRS Filed Aug. 21, 1963 4 Sheets-Sheet 2 I A bill/14E 0/1 INVENTOR. WALTER P. BAERMAN N M09417, 4M,M& Want A 'r'r'Ys Nov. 30, 1965 w. P. BAERMANN TILT AND SWIVEL MECHANISM FOR CHAIRS 4 Sheets-Sheet 5 Filed Aug. 21, 1963 INVENTOR: R P. BAERMANN M & Wart ATT'YS Nov. 30, 1965 w. P. BAERMANN TILT AND SWIVEL MECHANISM FOR CHAIRS 4 Sheets-Sheet 4 Filed Aug. 21, 1963 INVENTOR.

WALTER P. BAERMANN BY M07 1. W, & $02" A'rrvs United States Patent C) 3,220,688 TILT AND SWIVEL MECHANISM FOR crrams Waiter P. Baez-mama, 600 Asheville Road, Waynesvilie, N.C. Filed Aug. 21, 1963, Ser. No. 303,643 7 Claims. (6!. 248384) This invention relates to tilt and swivel mechanisms and particularly to tilt and swivel mechanisms that are used on ofiice chairs and the like.

An object of this invention is to provide a tilt and swivel mechanism, suitable for use on ofiice chairs and the like, in which the spring parts, including those which adjust spring tension, are located within the tubular base of the chair.

Another object is the provision of a tilt and swivel mechanism in which height and tension adjustments can be accomplished by merely pushing a button or twisting a lever.

A still further object is the provision of a tilt and swivel mechanism that employs the method of compression rather than elongation of the spring member.

These and other objects and advantages will become obvious when the following description is read in light of the accompanying drawings, in which:

FIGURE 1 illustrates a typical tilt and swivel mechanism, of the type herein disclosed, as it is used on an ofiice chair;

FIGURE 2 is an exploded View of one embodiment of the mechanism;

FIGURE 3 is a sectional view of the embodiment shown in FIGURE 2;

FIGURE 4 is a front elevation of the embodiment shown in FIGURE 2;

FIGURE 5 is a sectional view of a modification of the embodiment shown in FIGURE 2;

FIGURE 6 is another modification of the embodiment shown in FIGURE 2;

FIGURE 7 is a front elevation of another embodiment of the tilt and swivel mechanism;

FIGURE 8 is a section taken alongline 88 of FIG- URE 7;

FIGURE 9 is a front elevation of yet another embodiment of the tilt and swivel mechanism;

FIGURE 10 is a section taken along line 10-10 of FIGURE 9;

FIGURE 11 is a front elevation of a preferred embodiment of the tilt and swivel mechanism;

FIGURE 12 is a section taken along line 1212 in FIGURE 11;

FIGURE 13 is a front elevation of another embodiment of the tilt and swivel mechanism;

FIGURE 14 is a section taken along line 14-14 in FIGURE 13; and

FIGURE 15 is a section taken along line 15-15 in FIGURE 14.

Generally described, the present tilt and swivel mechanism comprises a top plate suitable for mounting a chair seat or the like. Said top plate is tiltably mounted to a head casting which has an annular central opening. A tensioner shaft extends downwardly through said annular central opening. Said tensioner shaft is linked at its upper end to said top plate, whereby when said top plate is tilted, vertical movement is imparted to said tensioner shaft. Said head casting, with said top plate tiltably mounted thereto and with said tensioner shaft, is mounted rotatably in the tubular base of an oflice chair. A compression member, provided with means for adujsting the tension thereof and adapted to oppose the movement of said tensioner shaft is mounted within said tubular base. If it is desired, said compression member may also rotate or swivel with said head casting and said tensioner shaft. The performance of the present tilt and swivel mechanism is further improved if means are provided for adjusting the height of the top plate with respect to the tubular chair base.

In operation, the tilt and swivel mechanism functions as follows: when said top plate is tilted, the vertical movement of said tensioner shaft causes compression of said compression member, thus opposing the upward movement of the top plate and tending to restore said top plate, via said tensioner shaft, to the horizontal. Operation of the tilting mechanism is not dependent on the position of said mechanism with respect to the tubular base. The rotating function and the tilting function are independent of one another. Thus, the top plate may be tilted at the same time the head casting is being rotated within the tubular base.

Referring to the drawings in more detail, FIGURE 1 shows chair seat I mounted on top plate 2. Tilt andswivel mechanism 3 connects top plate 2 andtubular chair base 4.

In FIGURES 2, 3, and 4 one embodiment of the present invention is shown. Top plate 5 (which corresponds to plate 2 in FIGURE 1) hascorner holes 6 wherebytop plate 5 can be attached to a chair seat, as shown in FIG-URE 1.Top plate 5 has central hole 7 through which push ball 8 is attached bynut 9.Push block 10 is forcefitted over push ball 8, and is made of material hard enough to withstand the forces demanded of it, yet resilient enough to be force-fitted over push ball 8.Head casting 11 is attached totop plate 5 by means ofpivot arms 12,pivot pin 13,bushings 14,pivot tabs 15 andpin 16.

Top plate 5 is shown in the extreme upward position which is maintained bynotches 17 inpivot tabs 15 acting againstpivot arms 12. Downward movement oftop plate 5 moving aboutpivot pin 13 causes push ball 8 andpush block 10 to move downward againsthead 18 oftensioner shaft 19 extending throughcentral opening 20 inhead casting 11.Lower portion 21 ofhead casting 11 is threaded as isupper collar 22 ofspring housing 23.Compression washer 24 is welded or permanently attached totensioner shaft 19, and moves withtensioner shaft 19.Tensioner shaft 19, which resembles in form an automobile exhaust valve, is thick and round athead 18 and has asquare shaft 25. Compression washer 24 acts againstspring retainer washer 26, which in turn acts againstspring 27. Ratchethousing retaining washer 28, together withlower end 21 ofhead casting 11, forms the upper limit for movement ofspring retainer washer 26 andtensioner shaft 19.

Tensioner shaft 19 passes throughtensioner screw 29, which has either a square, splined, or a key-wayed hole in the center which allows upward or downward movement ofshaft 25.Tensioner screw 29 is threaded on the outside to receivespring tensioner nut 30, which holdsspring 27 withinhousing 23 by means oftensioner washer 31. Upward movement oftensioner shaft 19 is limited byretainer nut 32 which is held in position bypin 33. Lower end ofscrew 29 rests againstbumper washer 34, whilenut 32 turns againstbumper washer 35. Downward movement oftensioner shaft 19 is limited bytensioner shaft head 18 abutting againstbumper washer 36.

The sequence of the tilting operation then is as follows:top plate 5 pivots aboutpivot pin 13 pushing push ball 8 downward, Push ball 8 pushes againstpush block 10, which pushes againsttensioner shaft 19 at itshead 18.Compression washer 24 attached totensioner shaft 19 pushes againstspring retainer washer 26, compressing thespring 27 held againsttensioner washer 31.

Ratchet drivehousing 37 drives ratchetpawl 38. Ratchetpawl 38 in turn drives ratchethousing 39.Ratchet housing 39 has a central opening corresponding in shape to pushrod shaft 25 wherebyratchet housing 39 turns withtensioner shaft 19 about its perpendicular axis.Tensioner washer 31 andtensioner nut 30 are friction-held byspring 27. Hence,tensioner screw 29 can rotate without rotatingnut 30.

The sequence of spring tension adjustment, then is as follows: ratchetdrive housing 37 drives ratchetpawl 38, which in turn drives ratchethousing 39.Ratchet housing 39 rotates tensionershaft 19, which rotates inturn tensioner screw 29.Tensioner nut 39 held motionless byspring 27 acting againsttensioner washer 31, moves up or downtensioner screw 29 as it is rotated, thus, varying the tension ofspring 27.

Spring housing collar 22 rotates with respect totubular chair base 40 onannular bearing 41.Snap ring 43 prevents the entire tilt and swivel mechanism from being lifted out oftubular chair base 40.

FIGURE shows a modification of the embodiment of the tilt and swivel mechanism shown in FIGURES 2, 3, and 4. Instead of thecoil spring 27 used in FIGURES 2, 3, and 4,conical disc spring 44 is used in FIGURE 5. Downward motion oftensioner shaft 45 results in compression ofsprings 44 betweencompression washer 46 andtensioner washer 47. FIGURE 5 also illustrates a slight modification in the arrangement of the tension adjustment parts.Tensioner screw 48 extends downwardly throughspring housing 49.Tensioner nut 50 is a clinch nut which has acollar extension 50a.Collar 50a passes throughspring housing 49 and is clinched or staked over to provide a permanent bond.Tensioner shaft 45, in FIGURE 5, is round.Shaft 45 must be key-wayed or splined so thatshaft 45 rotates withscrew 48.

FIGURE 6 illustrates another form of compression device that can be used in conjunction with the instant tilt and swivel mechanism. Head casting 51,tubular chair base 52 and tensioner shaft 53 are all of standard design. Attached to shaft 53 iscompression washer 54. Head casting 51 has threadedrim 55.Tensioner housing 56 has threadedupper collar 57 which screws onto head casting 51 at threadedinner rim 55.Compression component 58, mounted insidetensioner housing 56, utilizes the elastic properties of stressed rubber. Therubber component 59 is contained within a metal sleeve 60 and vulcanized thereto.Rubber component 59 is also vulcanized to a central sleeve 61, through which passes tensioner shaft 53. Alternatively,rubber component 59 may be vulcanized directly to tensioner shaft 53. If it is desired,rubber component 59 may be cemented to outer sleeve 60 and inner sleeve 61 of tensioner shaft 53, rather than being vulcanized thereto.

FIGURES 7 and 8 show yet another embodiment of the present tilt and swivel mechanism. As shown in the drawings, head casting 62, which also serves as a spring housing, is attached to projectingtabs 63 oftop plate 64 by means ofpivot pin 65. In use,top plate 64 hinges or tilts about an axis passing throughpivot pin 65. Head casting 62 contains aspring 66, comprising a series of conical spring washers or other type of compression spring,

mounted concentrically about atensioner shaft 67, which is attached indirectly totop plate 64 by means oftensioner shaft end 68 andpivot tabs 69.Tensioner shaft end 68 is screwed onto the upper threaded end oftensioner shaft 67 and is cross-pinned to pivottabs 69, which are in turn staked or welded to thetop plate 64.Spring base plate 70 is welded totensioner shaft 67, thus, compressing thespring 66 against the restraining concentric shoulder in head casting 62. The entire sub-assembly oftop plate 64, head casting 62,spring 66 andtensioner shaft 67 is seated in mountingtube 71 and allowed to rotate freely within this tube with the assistance ofbushing 72 and 4.bumper washer 73. This provides for overall rotation of thetop plate 64, and the chair seat which is pivotally attached thereto. In use, tilting of thetop plate 64 exerts an upward pulling force onspring base plate 76 viatensioner shaft 67, thus compressing thespring 66.

Thetab 74 oflock lever 75 passes through a small opening in the wall of mountingtube 71, when thelever 75 is depressed againstlever spring 76. Thelever lock 75 is pivotally attached to mountingtube 71 by means of ahinge pin 77 passing through thelever lock 75 and apin tab 78 which has been welded to mountingtube 71. \Vhen lever lock 75 is held in the depressed state and thetop plate 64 is rotated, the projectingtab 74 of thelever lock 75 enters the mountingtube 71 to the extent that it engages the downward formedflanges 79 of thespring base plate 70. This prevents rotation ofspring 66 andtensioner shaft 67, causingtensioner shaft 67 to run either up or down the threads intensioner shaft end 68 determining the initial tilt tension onspring 66.Height adjustment shaft 80 prevents screw out oftensioner shaft 67.

Lever lock 75 also serves to hold head casting 62 within mountingtube 71. Aprojection 81 on the upper end oflever lock 75 rides within anannular groove 82 in head casting 62. This method of attachment simplifies assembly or required maintenance.

Height adjustment shaft 80 is fixed to mountingtube 71 by brazing, force-fitting or other suitable means, and extends downward into thetubular chair base 83.Metal bushing 84 andmetal sleeve 85 keep the shaft concentrically alinged Withintubular chair base 83. Aheight adjustment ring 86 contains anadjustment nut 87 which engages threads on theheight adjustment shaft 80. Thus, whenheight adjustment ring 86 is rotated by hand, theheight adjustment shaft 80 begins to move upward or downward withintubular chair base 83.Lock screw 88 prevents possible lift-out of the entire height adjustment assembly.

FIGURES 9 and 10 illustrate a still further embodiment of the instant tilt and swivel mechanism. As with the form of the invention shown in FIGURES 7 and 8, the embodiment shown in FIGURES 9 and 10 provides both a mechanism for adjustment of spring tension and a mechanism for adjustment of height.

Top casting 9:) is attached totop plate 89 by means ofpivot tabs 91 andpivot pin 92.Top plate 89 tilts by the upward rotation of a center point which. is located intensioner shaft end 93. Thetop plate 89 is shown in an extreme downmost position which is maintained by the bottom flange oftensioner shaft end 93 abutting against the limit of depression intop casting 90. Upper movement oftop plate 89 is checked by the notch configuration that exists betweenpivot tabs 91 and cooperatingconnection 94 in top casting 9t).Tensioner shaft end 93 is attached viapin 95 to pivottabs 96, which are in turn welded totop plate 89.Tensioner shaft 97 is threaded intotensioner shaft end 93, and extends downwardly through the annular central opening intop casting 99.Tensioner shaft 97 extends downwardly throughspring 98, which is a conical disc spring or other type of compression device. The upper end ofspring 98 is seated againsttop casting 90. The lower end of thespring 98 is held againstspring retainer 99. Tensioner casting 169, threaded and attached at the lower end oftensioner shaft 97, moves withtensioner shaft 97 and againstspring retainer 99.

The sequence of spring compression is, then, as follows:top plate 89 tilts where the upward rotation of a center point located intensioner shaft end 93 about an axis or pivot point located inpivot pin 92. Upward movement oftop plate 89 results in upward movement oftensioner shaft 97 viapivot tabs 96 andtensioner shaft end 93. Spring tensioner casting moves upward withtensioner shaft 97 forcingspring retainer 99 upward, compressingspring 98.

Spring tensioner casting 100 moves up and down on the threaded part oftensioner shaft 97 between upper limitingnut 101 and lower limitingnut 102. When tensioner casting 100 is nearestupper limit nut 101, strongest tension is accomplished and vice versa as it approaches lower limitingnut 102. Aprotrusion 103 on tensioner casting 100 extends downwardly and rotates close to the wall oftubular chair base 104. Thebottom push button 105 inlower casting 106,opposite slot 107 intubular chair base 104, is the tension adjustment push button. Whentension adjustment button 105 is depressed, it moves throughslot 107 intubular chair base 104 into the path of rotatingtensioner casting protrusion 103. This stops the rotation tensioner casting 100, forcing it to move upward or downward along the threads oftensioner shaft 97.

The sequence of tension adjustment then is as follows:top plate 89 is rotated via the chair to which it is attached. At the same time,tension adjustment button 105 is depressed, moving it throughslot 107 andtubular base 104 and into the path of theprotrusion 103 of tensioner casting 100. This forces tensioner casting up or down against the spring, thus varying tension.

Top casting 90 andjack screw housing 108, because of multiple friction forces, swivel together uponswivel bearing 109.Jack screw housing 108 is held with the remainder of the unit totubular chair base 104 at snap ring 110, which also acts as a bumper for quiet operation. Bottom casting 106 is permanently attached totubular chair base 104, and contains twopush buttons 105 and 111. Thetop button 111 is the height adjustment button. When it is depressed, it falls into aslot 112 located in the bottom ofjack screw housing 108. When thehousing 108 is rotated, thus bringing theslot 112opposite button 111,button 111 falls into theslot 112. This stops the rotation of thejack screw housing 108. Top casting 90 continues to rotate and rides up the threads onjack screw housing 108 until the proper height is achieved.

The sequence of height adjustment, then, is as follows:top plate 89 is rotated via its attached chair, which in turn rotates top casting 90 andjack screw housing 108. While rotation is taking place, heightadjustment push button 111 is depressed, falling intoslot 112 at the bottom ofjack screw housing 108. This stopshousing 108 from rotating, but does not stoptop casting 90. Top casting then moves up threads in the jack screw housing.

FIGURES 11 and 12 show a preferred embodiment of the instant invention.Top plate 113 is attached to head casting 114 by means ofpivot tabs 115,pivot pin 116 andbushings 116a.Tensioner shaft 117 withhead 118 extends downwardly through the annular central opening in head casting 114. Within head casting 114 is ametal sleeve 119 withupper flange 120. Vulcanized to or cemented tometal sleeve 119 isrubber spring component 121.Spring unit 121 is vulcanized to or cemented totensioner shaft 117.Spring retainer washers 122 are welded totensioner shaft 117 at each end ofspring unit 121.

Push ball tension adjustment handle 123 is attached totop plate 113 bytension adjustment screw 124.Screw 124 is held totop plate 113 bybushing 125. Push ball tension adjustment handle 123 is connected to head 118 oftensioner shaft 117 bypush block 126. Thepush block 126 is made of material hard enough to withstand forces demanded of it and yet with enough resilience to be force-fitted over the push balltension adjustment handle 123.Push block 126 pushes and slides slightly againsthead 118 oftensioner shaft 117.

The sequence of tilting is as follows: pivotingtop plate 113 about an axis or pivot point lying withinpivot point 116 causes push balltension adjustment handle 123 and push block 126 to push againsthead 118 oftensioner shaft 117, compressingrubber spring unit 121.

Push ball tension adjustment handle 123 swings through a 200 arc with a total up and down adjustment space of A; of an inch along the threads oftension adjustment screw 124. Thehandle 123 is merely moved until the desired tension is obtained. Alternatively, instead of thehandle 127, a knob (not shown) may be provided.

FIGURES 13, 14, and 15 show yet another embodiment of the present invention.Base plate 128 is fastened to head casting 129 by means ofpivot tabs 130,pivot bolt 131,pivot nut 132 andnoiseless bearings 133. Head casting 129, is secured totubular chair base 134 by anexpansion ring 1 35. Astop plate 128 is rotated the head casting 129 turns between bearingsurfaces 136 and 137.Tensioner shaft 138 is pinned to pivottabs 139 bypin 140.Base shaft collar 141 fits on top oftubular chair base 134. Seated againstbase shaft collar 141 are conical disc springs 142. The conical disc springs 142 are retained at the bottom by aplate 143, which moves vertically on tworunners 144 which prevent theplate 143 from turning within thetubular chair base 134.Plate 143 is threaded ontotension adjusting shaft 145. At the bottom end oftension adjusting shaft 145 is astop 146 and abearing surface 147. Stop 146 is bolted totensioner shaft 138.

As thetop plate 128 is tilted, it rotates aboutpivot bolt 131 thus raising thetensioner shaft 138 thus raisingtension adjusting shaft 145, which in turn compressesspring 142.

For the adjustment of the spring tension one engages lift-upkey 148, which pivots on apin 149, into one of fourslots 150 which radiate from the center of tension adjustingshaft collar 152. By rotating thetop plate 128, tension on thesprings 142 may be increased or decreased, sincetension adjusting shaft 145 now rotates with respect tonon-rotatable plate 144 andbolt 151, which thus move up or down alongtension adjusting shaft 145. While adjustment is being accomplished, head casting 129 and tension adjustingshaft collar 152 as a unit rotate on bearing surface 136. When lift-upkey 148 is returned to its normal vertical position, tension is no longer adjusted by rotating the to plate 128.

The invention is hereby claimed as follows:

1. A resiliently-biased tilt mechanism comprising a vertical, hollow, mounting post, including a head on the upper end of said post, a substantially horizontal, tiltable member pivotally supported on said head with the pivot axis thereof being substantially horizontal and laterally displaced with respect to the longitudinal axis of said post, a resiliently deformable member in said post, means holding one part of said deformable member against axial displacement in said post, and means coacting between another part of said deformable member and said tiltable member at a position on the latter directly above said post to deform resiliently said deformable member when said tiltable member is tilted about said pivot axis in a direction away from the substantially horizontal position, and bias-adjustment means for adjusting, in response to rotation of said tiltable member, the resilient bias of said deformable member against said tilting of said tiltable member.

2. A mechanism as claimed inclaim 1 wherein said deformable member is resiliently deformable in longitudinal compression.

3. A tilt mechanism as claimed inclaim 1, a vertical shaft movable longitudinally in said post, means connecting the upper end of said shaft with said tiltable member, and means connecting the lower portion of said shaft and said another part of said deformable member and providing the connection between shaft and said deformable member to cause said deformable member to deform resiliently when said tiltable member is tilted.

4. A tilt mechanism as claimed inclaim 3 wherein said deformable member is a longitudinally compressible coil spring.

5. A tilt mechanism as claimed inclaim 3 wherein said deformable member is a series of conical disc springs.

6. A tilt mechanism as claimed inclaim 3 wherein said deformable member is an elastomer tube surrounding said shaft.

7. A tilt mechanism as claimed inclaim 1, means on said post supporting said head, said tiltable member and said deformable member for swivel movement as a unit on said post, and manually operable means movable from an inactive position permitting said swivel movement without said biasadjustment to an active position, in

References Cited by the Examiner UNITED STATES PATENTS Trapp 248406 Schaifner 297-205 Bethke 248-402 Herold 248-375 Stewart 2671 Clay 2671 which said bias-adjustment means is activated byrotation 10 CLAUDE A. LE ROY, Primary Examiner.

of said tiltable member.

Claims (1)

1. A RESILIENTLY-BIASED TILT MECHANISM COMPRISING A VERTICAL, HOLLOW, MOUNTING POST, INCLUDING A HEAD ON THE UPPER END OF SAID POST, A SUBSTANTIALLY HORIZONTAL, TILTLABLE MEMBER PIVOTALLY SUPPORTED ON SAID HEAD WITH THE PIVOT AXIS THEREOF BEING SUBSTANTIALLY HORIZONTAL AND LATERALLY DISPLACED WITH RESPECT TO THE LONGITUDINAL AXIS OF SAID POST, A RESILIENTLY DEFORMABLE MEMBER IN SAID POST, MEANS HOLDING ONE PART OF SAID DEFORMABLE MEMBER AGAINST AXIAL DISPLACEMENT IN SAID POST, AND MEANS COACTING BETWEEN ANOTHER PART OF SAID DEFORMABLE MEMBER AND SAID TILTABLE MEMBER AT A POSITION ON THE LATTER DIRECTLY ABOVE SAID POST TO DEFORM RESILIENTLY SAID DEFORMABLE MEMBER WHEN SAID TILTABLE MEMBER IS TILTED ABOUT SAID PIVOT AXIS IN A DIRECTION AWAY FROM THE SUBSTANTIALLY HORIZONTAL POSITION, AND BIAS-ADJUSTMENT MEANS FOR ADJUSTING IN RESPONSE TO ROTATION OF SAID TILTABLE MEMBER, THE RESILIENT BIAS OF SAID DEFORMABLE MEMBER AGAINST SAID TILTING OF SAID TILTABLE MEMBER.

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