US2056965A - Posture chair - Google Patents

Description

Get. 13, 1936. w E H D 2,056,965

POSTURE CHAIR Filed Dec. 20, 1934 7 Sheets-Sheet 1 INVENTOR XQQALTER Ff HER 01.13.

ATTORNEY.

Oct. 13, 1936. w. F. HEROLD 2,056,965

POSTURE CHAIR Filed Dec. 20, 1934 ATTORNEY.

W. F. H EROLD POS'I'URE CHAIR Oct. 13, 1936.

Filed De c. 20, 1954 7 Sheets-Sheet I5 INVENTOR WALTER F HERDLD.

ATTORNEY Oct. 13, 1936.

INVENTOR BBLTER F HERDLD.

ATTORNEY.

0a. 13, 1936. w. F. HERO LD 2,056,965

POSTURE CHAIR Filed Dec. 20, 1934 7 Sheets-Sheet 5 INVENTOR LTER F HERULD.

fi Wm ATTORNEY Oct. 13, 1936. w. F. HEROLD 2,056,965

POSTURE CHAIR Filed Dec. 20, 1954 I 7 Sheets-Sheet 6 m4 \/64 M2 /56 as INVENTOR \QIHL'TER F HER cum.

Y W Wm ATTORNEY.

061;. 13, 1936. w HERQLD 2,056,965

POSTURE CHAIR Filed Dec. 20, 1954 7 Sheets-Sheet '7 INVENTOR WALTER F HER r111 ATTORNEY Patented Oct. 13, 1936 2,056,965

UNITED STATES PATENT OFFICE.

POSTURE CHAIR Walter F. Herold, Bridgeport, Conn., assignor'to The Bassick Company, Bridgeport, Conn., a corporation of Connecticut Application December 20, 1934, Serial No. 758,382

6 Claims. (01. 155-164) The present invention relates to improvements With the above and other objec s in View. in chairs with tilting backs and particularly chairs b diments of my nvent on are shown in the 9.0-- of the so-called posture type, in which the back comp y ng drawings and these embodiments will is arranged to be adjusted to fit the back of the be hereinafter more fully described with referuser of the chair, and in which a resilient support ence t ereto, and the invention will be finally 5 is provided for the back. In chairs of this type pointed out in the claims.

heretofore in use coil springs were used for the In the drawings: purpose of providing a yielding or resilient sup- Fig. 1 is a side elevation of a complete chair port for the chair back, the latter being pivotally bodying a tiltable chair back mechanism acsupported for tilting movement. In these struccording to one embodiment of my invention. 10 tures the relatively moving metal parts of the F g. 2 is a vertical longitudinal sectional view pivot joint of the back were in contact and under oi the chair back tilting a adjusting mechapressure 1 th springs so th t duflng l ti msm, according to the embodiment of the invenmovement there was considerable surface friction, i n illustrated in Fig. 1.

with the result that the tilting action was irreg- F g. 3 is a plan View t the C a r seat 16 ular, frequent adjustments were necessary, and being removed. the parts would creak and squeak. Also because Fig. 4 is a vertical sectional view taken along of the great leverage necessary, due to the disthe line 4-4 of Fig. 2, the chair seat being retance between the axis of tilt beneath the chair moved.

and the point of engagement of the users back Fig. 5 is a side elevation of a chair back tilting with the chair back, very large and strong springs mechanism, according to a modified embodiment were necessary. They furthermore required freof my invention.

quent lubrication, and due to the constant pres- Fig. 6 is a forward end elevation thereof. the ence of lubricant would collect dirt and dust and chair ea being ov d.

were apt to soil the floor covering should the lubri- Fig. 7 is a vertical sectional view taken along 25 cant drip. For the most part these springs, 00- line 1-1 of Fig. 5. operated with levers or cams, the springs and Fig. 8 is a side elevation of a chair back tilting the levers or cams having a number of frictionmechanism, according to another modified form ally engaging bearing surfaces under the relatively of my invention.

great pressure of the springs, all of which sur- Fig. 9 is a perspective view of the chair back faces constituted wear points which would squeak tilting mechanism shown in Figs. 1 to 4, one of under the slightest movement, unless constantly the spider arms being shown partially broken lubricated. away.

An object of the present invention is to provide Fig. 10 is a perspective view of the chair back a chair in which the tilting action of the chair tilting mechanism shown in Figs. 5 to 'l. 35

back takes place in a hinge joint of rubber, the Fig. 11 is a side elevation, with parts broken rubber being in the form of a tubular member away and partially in section, of a chair back tiltdisposed under permanent pressure between two ing'mechanism according to a further modified coaxially movable members disposed one within form of my invention.

the other and to each of which the rubber is in Fig. 12 is a forward end elevation thereof, the

efiect bonded or permanently secured, and relaback member being removed, and parts of the tive movement between these members being remechanism broken away.

siliently effected by the torsional strain set up Fig. 13 is a top plan view, parts being broken in the compressed rubber. Because of the comaway.

pactness of this structure and the potential pres- Fig. 14 is a perspective view of the chair back 45 sures obtainable within relatively small dimentilting mechanism shown in Figs. 11 to 13, the sions the joint may be conveniently placed at chair back member being shown partially broken any desired position relatively to the chair seat, away. and whereby the various adjustments to be made Fig. 15 is a side elevation of a further modified by the user may be most conveniently made by form of the invention. 50 easily operated and acccessible means. Another Fig. 16 is a plan view thereof. object is to provide joint means which will be Fig. 17 is a perspective view of the chair bac noiseless in operation, will not deteriorate to any tilting mechanism shown in Figs. 15 and 16, the appreciable extent even after long and excessive chair back member being shown partially broken 35 use, and will require no lubrication. awa,y

Fig. 18 is a plan view of the bracket bearing member employed.

Fig. 19 is a plan view of the tilting frame member employed.

Fig. 20 is a plan view of the tension adjustment lever member employed. f

Fig. 21 is a perspective view of the joint element employed.

Similar reference characters indicate correl3l3 at a point near the rear edge of the seat,-

and comprises a bracket having a pair of side arms |4-l4 connected by an integral bridge strut portion I 5, and having formed on their ends cylindrical bearing portions l6- i6 disposed in aligned and spaced relation to each other. The side arms are secured between the angle arms l3l3 by means of rivets H. The joint element comprises an outer tubularmember i8, an inner tubular member i9, and a cylindrical body of rubber 20 between the members l8 and i9 and being in effect bonded to their surfaces, so that upon relative rotary movement between the members I6 and I9 the rubber body is put under torsional strain. In practice the rubber body is bonded to the inner member l9, as by vulcanization, and is then forced into the outer member l8 under great pressure, its diameter prior to insertion in the member I8 being considerably greater than the interior diameter of the member l8, so that the rubber is thus highly compressed and is in effect bonded to the inner surface of the member 3 by the great surface friction set up between them under compression.

The ends of the rubber body project beyond the ends of the outer member l8, as at 2I2l, and the ends of the inner member i9 project beyond the rubber body and are provided with diametrically extending semi-circular cross-section grooves 22-22 for locking this inner member to the tilting frame member, as will presently more fully appear.

The tilting back supporting frame member 23 is of general U-shape in plan and is provided in its forwardly projecting arms with apertures 24-24 in which are engaged the ends of a tie-bolt 25 extending through the inner member l9, one end of this tie bolt being headed, as at 26, and the other end having a nut 21 screwed thereon. Upon the inner sides of the arms of the tilting frame member 23, in diametrically extending relation to the holes 24-24, there are provided semi-circular cross-section ribs 2828 which engage the grooves 2222 and thereby rigidly lock the inner joint member i9 to the tilting frame rubber 23, the member l9 providing a supporting spacer or strut between the arms of the tilting frame member.

Upon the bearing portions l6l6 there are formed integral flanges 29--29 having stop surfaces 30--39 and 3I3l, angularly disposed with relation to each other, and against which the transverse portion of the tilting frame member engages in its limit positions, the surface 36 being Shown in full lines in Fig. 2, and the surface 3| being engaged in the limited tilting position, as shown in dotted lines.

Within the space between the bearing portions l6--l6, a tension adjustment lever 32 is disposed and projects beneath the bridge portion l5, its collar portion 33 being engaged about the intermediate portion of the outer joint member 19 and secured thereto by a set screw 34, the member l8 having a recess 35 therein in which the end of the set screw lockingly engages. An adjusting screw 36 having a hand wheel or nut 31 at its end is engaged in a threaded opening 33 in the end of the lever 32 and bears at its upper end upon the under surface of the bridge portion l5.

It will be obvious that by adjusting the screw 36 the outer joint member I 9 is rotated with respect to the bracket l4 and the inner joint member i9,

and through the torsional strain imposed on the rubber 20 any desired initial tension may be set up in the latter, the greater the initial tension the greater force required to tilt the tilting frame member 23, which latter is connected with the chair back, as will presently more fully appear.

The transverse portion of the tilting frame member projects below the side arms and is provided upon its rearward face with a vertically disposed groove 39 in which is engaged the vertically disposed rib 40 of a vertical adjustment plate member 4|, this plate member being ad.- justably connected to the tilting frame member by means of a bolt 42 extending through the plate member and through a vertical slot 43 in-the tilting frame member, a tightening nut 44 being engaged upon this bolt and provided with a sliding cross-rod 45 for manually turning it. By loosening the nut 44 the plate member may be vertically adjusted to any desired position, which adjustmentraises or lowers the chair back relative to the chair seat.

The plate member 4| is provided near its upper end and adjacent its vertical edges with ears 4646 in which are engaged the ends of a shaft 41, upon which are also engaged ears 4848 of a chair back supporting frame member 49. In order to obtain angular adjustment of the chair back supporting frame member 49 with respect to the chair seat a coil spring 59 is disposed between the frame member 49 and an upwardly extending ear 5| provided upon the upper end of the plate member 4|, the frame member 49 having a pocket 52 formed therein in which one end of the spring is engaged and the ear 5| having a pocket 53 formed therein in which the other end of the spring is engaged. This spring is located above the shaft 41, and below this shaft there is provided in the frame member 49 an adjusting screw 54 having a hand wheel 55 at one end, its other end bearing against the outer face of the plate member 4|. It will be obvious that manually engaged by said transverse portion, as

by adjusting the screw 54 the frame member 49 chairback by the interposing of the compressed tensioned rubber body 28 between the outer and inner joint members l8 and i8, and by the disposition of the rubber ends 2|-2l an outer joint member away from the sides of the arms of the frame 23, so that'the relatively movable parts are entirely insulated by the rubber against frictional contact. When the back is tilted the building up of tension in the rubber body, while permitting an easy tilting action, prevents sudden or hard tilting to the limit position, and provides a smoothly resilient but at the same time a substantial support for the users back. By adjusting the tension in the rubber body by means of the adjustment screw 36 the tensional resistance may be regulated to exactly suit the needs of the userof the chair, and this feature, in combination with the vertical and angular adjustment, provides a posture chair. which may be made to accommodate itself in the most efficient and desirable manner to the individual requirements of the user. As no lubrication is required the parts will remain indefinitely in perfect working order without attention, and because of the absence of lubricant dirt and dust will not readily collect as has been the case withv other types of mechanisms employed in posture chairs. Inasmuch as this type of chair is used for the most part by women, the cleanliness of the structure, and the ease with which its adjustments may be made are highly desirable and advantageous features.

In Figs. 5 to 7 and 10 I have illustrated a modi-' fied form of the invention in which the joint element is provided in the rear of the seat i2, and comprises a vertically disposed bracket member 60 having a pair of horizontal forwardly extending arms 6l-6l integrally formed thereon, and which are respectively secured to the angle iron spider-arms i3--l3 by means of rivets 62. A vertically extending groove 63 is provided in the rearward face of the bracket member 60 and is engaged by a vertically extending rib 64 formed on a joint supporting frame member 65, a vertical slot 66 being formed in the bracket member 68, which is engaged by a bolt 61, set in the frame member 65 and having upon its threaded end a nut 68, adapted to be tightened against the bracket member 60 to secure the frame member 65 in its vertically adjusted position. Obviously by loosening the nut 68 the frame member 65 may be vertically adjusted.

The frame member 65 is provided at the respective ends of its upper portion with a pair of rearwardly and upwardly extending arms 68-68, having bearing openings 1818 therein in which are mounted the ends of the joint member, as will now more fully appear. The joint member comprises an outer tubular member 1 I, an inner tubular member 12, and an intermediate cylindrical body of rubber 13 between them, this rubber body being highly compressed and confined between the members 1| and 12 and being in effect bonded to their surfaces, so that upon relative rotary movement between the members 1i and 12the rubber body is put under torsional strain. In practice the rubber body 13 is bonded to the inner member 12 as by vulcanization and is then forced into the outer member 1| under great pressure, its (11- ameter prior to insertion in the member 1| being considerably greater than the interior diameter of the member] I, so that the rubber body is thus highly compressed and is in effect bonded to the inner surface of the member 1| by the greater" surface friction set up between them under compression. The ends of the rubber project beyond the ends of the outer member 1|, as at 14-44, and the ends of the inner member 12 project beyond the rubber body and are provided with diametrically extending semi-circular-cross-section grooves 1515. Within the bearing openings 18-18 of the arms 68- -88 there are rotatably engaged cylindrical bushings 18 and 11, the bushing 18 being of the same thickness 'as the arm 68 engaged thereby, and the bushing 11 projecting outwardly from the arm 68 with which it is engaged, and upon the inner faces of each of these bushings there are provided, in diametrically extending relation to the apertures therein, semi-circular cross-section ribs 18-18 which engage the grooves 1518, of the inner joint member 12 and thereby rigidly lock this inner joint member to the bushings 16 and 11. A tie bolt 18 having a head at one end extends through .the openings of the bushings 18 and 11 and through the bore of the tubular inner member 12 and being locked to the bushing 11 by a cross-pin 88.

Upon the projected end of the bushing 11 there is engaged the hub of a tension adjustment lever 8| which is secured thereto by means of a set screw 82, the end of this lever being provided with a threaded opening 83 in which is engaged an adjusting screw 84 having a hand wheel or nut 85 at its end, this adjusting screw bearing against a projected ear 86 integrally formed upon the frame member 65.

The outer joint member 1| is engaged in a cylindrical tubular bearing member 81, and is secured thereto against rotation by means of a set screw 88, this bearing member 81 being provided with an upwardly extending-bracket arm 88 to which are secured the uprights 56' of the chair back, the bearing member 81 and arm 88 constituting a tilting back supporting member.

A forwardly projected lug 88 is integrally formed upon the bearing member 81 and is provided with aninclined under face 8| which engages the upper inclined face 82 of an angle adjusting cam member 83 slidably engaged upon the frame member 65. This cam member is provided with a threaded passage 84 which is engaged by a. feed screw 85, having bearing in a pair of ears 86-86 integrally formed upon the upper surface of the frame member 65, and which is'provided at its end with a hand wheel 91. By turning the feed screw 85 the cam member 83 is slidably moved upon the frame member 65 and through its inclined upper surface imparts rotary adjustment to the bearing member 81, thereby angularly adjusting the position of the chair back with relation to the chair seat. The torsional pressure produced in the rubber body 13 tends to rotate the member 81 in clock-wise direction, as seen in Fig. 5, and thereby presses the lug 88 against the cam member 83.

By adjusting the tension screw 84 the amount of tension in the joint member may be regulated,

' the movement of the lever 8| in clock-wise direction setting up increased tension in the rubber body, so that the resistance to tilting of the back 88 with the cam member 83 limits the forwardly tilted position of the chair back. In order to pro- "vide a limit for the rearward tilting movement I provide a lug 88 upon the bearing member 81, which contacts a lug .88 formed upon the frame member in the rearwardly tilted position of the back.

In Fig. 8 I have illustrated another modified form of the invention in which the joint member is mounted in relation to the centrally disposed integrally formed a block portion IOI disposed" between the angle-iron spider arms I3-I3 and secured thereto by means of screws I02, and also integrally formed upon this member I there areprovided a pair of cylindricaltubular bearing portions I03--I03 within which is engaged the joint member, similar to that of the embodiment shown in Figs. 1 to 4 and 9, and comprising the outer tubular member I0, the inner tubular member I3, and the cylindrical rubber body 20 interposed between them. The structure is substantially the same as that illustrated in Figs. 1 to 4 and 9, except that the tilting back supporting frame member 23a is considerably longer, so that it extends from the joint member to. the rear of the seat where it is provided with the same vertical and angular adjustment means. The sides of the member 23a are connected near the forward ends by means of a rib I04 which bears upon the movement limiting flanges 20-29 formed upon the bearing portions I03, these flanges being provided as in the embodiment shown in Figs. 1 to 4 and 9, with angularly disposed movement limiting surfaces 30 and 3I. The tension adjustment lever 32 projects vertically downward and the adjustment screw 38 bears upon a bearing boss I05 formed upon the pedestal member I00.

In Figs. 11 to 13 and 14 I have illustrated a further modified fonn of the invention, in which the joint element is provided at the upper end of the vertical chair back supports, these supports I00-403 being of right-angular form and having their lower ends secured to the angle-iron spider arms I3'I3 of the chair seat I2 by means of rivests I 01. A bracket member I08 is provided at its lower end with a transversely extending mounting portion I 09 having flanges H0 at its ends, and which is secured to the upper ends of the supports'I05-I05 by means of bolts I I l. The upper end portion of the bracket I00 projects forwardly in right angular relation and is provided with a pair of cylindrical tubular bearing portions II2I I2 within which are engaged the ends of the joint element. The joint element in this case comprises an outer tubular member I I3, an inner cylindrical spindle member I I4, and a cylindrical body of rubber II5 between them, and which, as in the other embodiments of the invention is in effect bonded at their surfaces. The ends of the outer tubular member I I3 are rotatably engaged in the bearing'portions II2- II2, and .the spindle member H4 is provided at one end with a reduced extension I I0 upon which the hub portipn of a tension adjustment lever I I 1 is secured b I means of a set-screw .I I0, a tension adjusting screw IIB having a hand wheel I20 being engaged in an ear I2I integrally formed upon the frame member I08 and bearing upon the end of the lever II1.

The tilting chair back supporting bracket I22 is provided with a cylindrical bearing portion I 23 engaged upon the outer member II3 of the joint element between the bearing portion II2II2, and secured thereto by means of a set-screw I24. A rearwardly projected lug I25 is formed upon the bearing portion I23 and is en ed by an adjustment screw I25 having a hand wheel I21 at one end and which bears upon a bearing portion I28 formed upon the bracket member I00 and which through adjustment adjusts the angularity of the chair back with respect to the seat I2.

Upon the forward face of the bracket member I22 there is formed a vertically disposed rib I20 which is engaged by a vertically'disposed groove I30 provided in the chair back supporting member I3I, this member I3I being provided with a vertical slot- I32 en aged by a bolt I33 set in the bracket member I22 and having an end nut I34 upon its end which bears against themember III- to secure the same in vertically adjusted position. By loosening this nut the member I3I may be vertically adjusted with respect to the bracket member I22 in order to obtain vertical adjustment of the chair back with relation to the chair seat.

Adjustment of this screw I 40 adjusts the angle of the chair back with respect to the member I.

In operation, rearward rivet pressure against the chair back I31 swings the bracket member I22 downwardly in clockwise direction as seen in Fig. 11. This action imposes a torsional strain in the rubber body H5 in substantially the same manner as described in connection with the other embodiments. Due to the relatively short lever arm between the axis of the joint member and the point of engagement of the user's back with the chair back I31 a substantially smaller joint element may be employed with the same eifect than is the case where there is a substantially longer lever arm, as in the embodiments shown in Figs. 1 to 4 and 9, 5 to 'land 10, and 8.

In Figs. 15 to 17 I have shown a further modiflcation in which the joint element is mounted upon the chair back. A transversely extending member I42 is secured to the upper ends of the supports I06 in substantially the same manner as employed in the embodiment shown in Figs. 11 to 13 and 14 by means of bolts I43, and is provided with a vertically extending standard I44 provided upon its rear face with a vertically extending rib I45 which is engaged by a vertical extending groove I46 provided in a bracket member I41, a bolt I48 extendingthrough a slot I 49 formed in the standard I44 being engaged through a bearing portion I50 formed in the bracket I41 and having a hand nut I5I screwed thereon for securing the bracket I41 to the standard I44, th bracket adapted to be vertically adjusted with relation to the standard by loosening the nut III.

At the upper end of the bracket I41 there is provided a flange portion I52 extending at an upward angle of approximately 45 and upon this flange portion there is formed a cylindrical tubular bearing portion I53. A tilting back supporting frame member I54 is pivotally connected at its sides to the bearing portion I 53 by means of a tie-bolt I55 extending through the bearing portion I53, there preferably being a rubber or other type of oil-less and noiseless bearing bushing I56 interposed between the bearing portion I53, and the bolt I 55 carrying the tilting frame member, so that the latter is permitted to have tilting movement relative to formed a pair of spaced cylindrical tubular bearing portions I58--I58, the joint element comprising the outer tubular member I59, the inner tubular member I60, and the cylindrical body of rubber I6I between them, being engaged inthese bearing portions I58-I58. The ends of the inner joint member I60, which project with respect to the rubberbody, as in the vfirstembodiment of the invention, are provided] with semi-circular cross-section diametrically extending grooves I62I62 which lockingly engage. diametrically extending ribs I6 3-A63 formed upon the inner surfaces of rearwardly extending arms of a U-shape bracket- I64 secured to the chair back I65, a tie bolt I66 having a head at one and extending through the-apertures in the arms I64 and through the .bore of the tubular member I60 and being secured by means of a nut I61. 7

A tension adjustment lever I68 has its hub portion secured upon the outer joint member I59 by means of a set screw I69, and is provided with an adjusting screw I10, having a hand nut I1I engaged in a threaded-passage I12 in its end and bearing upon the rib I51.

The flange I52 is provided at its forward edge with an ear I13 in which isengaged an adjustment limit stop screw I14 bearing upon the under side of the rib I51. An upwardly projecting ear I15 is formed upon the bearing portion I53 and is also provided with a limit st'op adjustment screw I16 against which the upper side of the rib I51 engages in the rearwardly pressed position of the chair back. By adjusting the screw I14 the normal front to rear position of the chair back with respect to the chair seat I2 may be adjusted to suit the particular user of the chair, and by adjusting the screw I16 the limit of rearward tilt may be reg ulated as desired.

At the lower portion of the chair back there are provided a pair of U-shaped brackets I11 I11 to which the forward ends of a pair of flexible strap members I18 are connected by crosspins I19-I19, the rearward ends of these straps being connected by studs I80I80 to the bracket member I41. The axes of the joint element and the cross-pins I19, and the axes of the bearing I53 and the studs I80, are respectively in parallel vertical planes, and the tilting frame member I54 and the strap members I18 are in inclined parallel planes, so that the structure forms a parallelogram. The normal tendency of the chair back under the torsional pressure of the joint element is to swing in counter-clockwise direction, as seen in Fig. 15, the bracket I64 tending to straighten out with respect to the tilting frame member I54, but due to the connection of the lower end of the chair back to the bracket member I41 by means of the straps I18-I18 the bracket I64 is pulled in clock-wise direction and the tilting frame member is normally pulled down against the stop I14 under the torsional pressure of the joint element. As rearward pressure is applied by the user against the chair back the tilting frame member I54 swings rearwardly in counter-clockwise direction, this action imposing tension in the joint element. By adjusting the screw I10 the initial tension set up in the joint element may be adjusted to suit the particular requirements of the user of the chair, this initial tension determovement with respect .to said seat comprising ner joint member and exteriorly bonded to the outer joint member, said sleeve holding one of said joint members in concentric spaced relation to the'other, means fixedly connecting one of said joint members to said frame element,

means fixedly connecting the other of said joint members to said back element, said torsion sleeve member beingtensioned in a direction to force said back element forwardly in the direction of said seat, and stop means adapted to limit the forward movement of said back element 'under pressure of said torsion member, said back element adapted to be moved rearwardly relatively to said seat under the rearward pressure of the occupant of said seat and to further tension said rubber sleeve member.

2. A chair having a seat supporting frame element, a seat carried thereby and a back element, and joint means connecting said back element to said frame element whereby said back element is adapted to have back and forth movement with respect to said seat comprising a pair of joint members one within the other and a rubber tor-' sion sleeve member between said joint members interiorly bonded to the inner joint member and exteriorly bonded to the outer joint member, said sleeve holding one of said joint members in concentric spaced relation to the other, means fixedly connecting one of said joint members to said frame element, means fixedly connecting the other of said joint member to said back element, said torsion sleeve member being tensioned in a direction to force said back element forwardly in the direction of said seat, stop means adapted to limit the forward movement of said back element under pressure of said torsion member, said back element adapted to be moved rearwardly relatively to said seat under the reaward pressure of the occupant of said seat and to further tension said rubber sleeve member, and stop means adapted to limit the rearward movement of said back element whereby in the rearward limit position the back of the occupant is solidly sup ported by said stop means and the degree of tension applied to said torsion sleeve member is limited to a predetermined extent.

3. A chair having a seat supporting frame element, a seat carried thereby, and a back element, and joint means connecting said back element to said frame element whereby said back element is adapted to have back and forth movement with respect to said seat comprising a pair of joint members one within the other and a rubber torsion sleeve member between said joint members interiorly bonded to the inner joint member and exteriorly bonded to the outer joint member, said 511501 1; niembersoneywithin the other I'and 'a rubber torsion sleeve member between said joint members interiorly bonded to the inframe element, means fixedly connecting theother of said joint members to said back element, means arranged to retain one of said joint members in relatively rotated position with respect to the otherjoint member to initially tension said torsion sleeve member to force said back element forwardly in the direction of said seat, stop means adapted to limit the forward movement of said back element under .pressure of said torsion member, said back element adapted to be moved rearwardly relatively to said seat under the rearward pressure of the occupant of said seat and to further tension said rubber sleeve member.

4. A chair having a seat supporting frame element, a seat carried thereby and a back element, and joint means connecting said back element to said frame element whereby said back element is adapted to have back and forth movement with respect to said seat comprising a pair of joint members one within the other and a rubber torsion sleeve member between said joint members interiorly bonded to the inner joint member and exteriorly bonded to me outer joint member, said sleeve holding one of said joint members in concentric spaced relation to the other, means fixedly connecting one of said joint members to said frame element, means fixedly connecting the other of said joint members to-said back element, adjustment means arranged to rotate and retain one of said joint members relatively to the other joint member to apply variable initial tension to said torsion sleeve member in a direction to force said back element forwardly in the direction of said seat, stop means adapted to limit the forward movement of said back element under pressure of said torsion member, said back element adapted to be moved rearwardly relatively to said seat under the rearward pressure of the occupant of said seat and to further tension said rubber sleeve member.

5. A chair having a seat supporting frame element, a seat carried thereby, and a back element, and joint means connecting said back element to said frame element whereby said back element is adapted to have back and forth movement with respect to said seat comprising a pair of joint 50 members one within the other and a rubber torsion sleeve member between said joint members interiorly bonded-to th inner joint member and exteriorly bonded to the outer joint member, said sleeve holding one of said joint members in concentric spaced relation to the other. means fixedly connecting one of said joint members to said frame element, means fixedly connecting the other of said joint members to said back element, adjustment means arranged to rotate and retain 1 one of said joint members relatively to the. other pressure of the occupant of said seat and to further tension said rubber sleeve member.

6. A chair having a seat supporting frame element, a seat carried thereby; and a back element, and joint means tiltably connecting said back element to said frame element, whereby saidback element is adapted to have back and forth tilting movement with respect to said seat, comprising a pair of joint members one within the other and a rubber torsion sleeve member between said joint members interiorly bonded to the inner joint member and exteriorly bonded to the outer joint member, said sleeve holding one of said joint members in concentric spaced relation to the other, means fixedly connecting one of said joint members to said frame element, means fixedly connecting the other of said joint members'to said back element, means arranged to retain one of said joint members in relatively rotated position with respect to the other joint member to initially tension said torsion sleeve member in a direction to force said back element forwardly in the direction of said seat, stop means adapted to limit the forward movement of said back element under pressure of said torsion member, said back element adapted to be tilted rearwardly rel-- atively to said seat under the pressure of the occupant of said seat and to further tension said rubber sleeve member, the angle between said back element and said seat being increased as said back element is tilted rearwardly.

WALTER. F. HEROID.

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