US2365200A - Adjustable chair - Google Patents

Description

Dec. 19, 1944. A. LORENZ v ADJUSTABLE CHAIR 2 Sheets- Sheet 2 Filed Mafch 16, 1942 INVENTOR A 721022 Lorenz ATTORNEY Patented Dec. 19, 1944 UNITED STATES. PATENT OFFICE 2,365,200 r ADJUSTABLE'OHAl'R Anton Lorenz, Chicago,'lll. Application March 16, 1942, Serial No. 434,849

' 19 CIaims. (cuss-45 My invention relates to chairs, and more particularly to, adjustable chairs .of the so-called .posture chair type, wherein the front portion of the seat, is pivoted to a support, the rear portion of the seat is hinged to a back-rest, and a mechanism is provided for an automatic variation in the angle between the back-rest and the seat when the seat is. moved from a sitting position into an inclined position and vic versa, so that the back-rest. automatically adjusts itself into position to support the backv of a person sitting on the chair.

One. objet of my invention is to provide an adjustable chair of above described type. wherein the mechanism for the automatic variation in the angle between the back-rest and the seat is of simple construction, so thatthe chair may be manufactured at low costs Another object of my invention is to :provide an adjustable chair of above described type equipped with adjusting means for a preadjustment of the relative position between the back-rest and the seat.

A further object ofmy invention is to provide.

an. adjustable. chair of above described type wherein the seatv may be moved from a substan-. tially horizontal sitting position into a forwardly inclined position under a simultaneous decrease of the angle. between the. baok-restIand the seat and wherein the seat may be moved from. the substantially horizontal sitting position into a. rearwardly inclined position under a simultaneous increase of the angle between. the. back-rest and. the seat.

- Still. another object of my invention is to provide a chair, wherein. the back-rest is pivoted to the seat'in such a manner, that a relative movement between the back-rest and the back of the user of the chair is practically eliminated during a relative movement between the back-rest and the seat.

In order to carry out my invention. in practice, I provid an adjustable chair comprising a. support, a seat, a back-rest, the front portion of said seat being pivoted to said support at a. stationary point, the back-rest being pivoted to the. rear portion of said seat, guiding link-means, one end of said guiding link-means being pivoted to said support at a \point, positioned in the front portion.

of the chair in. a plane below the horizontal plane of said front pivot oil-the seat, the other end of said guiding link-means being, hinged toan interfront pivot. from said sitting position into a rearwardly inclined. position and into a forwardly inclined position, said intermediate point of the back-rest being guided along a continuous circular path by said guiding means during a tilting. of. said seatwhereby the angle between the seat and the. back-rest is increased when the seat is tilted. from thesitting position into the rearwardly. inclined \position and. whereby said angle. is decreased when the seat is tilted from said sitting position into the forwardly inclined position, resilient; means arranged between said support and a movable part of the chair for urging said seatinto said forwardly inclined position, and limiting,.m'ean-s connected with the seat and arrangedfor cooperation withsaid. support for limiting the forwardly inclined position of the seat.

The above mentioned objects and advantages as well as other objects and advantages will be more fullydisclosed in the. following specification v reference being had to. the accompanying draw-- ings forming part. oi? this specification, wherein: Fig.. 1 is. a fragmentary side elevational View of an adjustable-chair according to the invention,

"Fig; 2" is a sectional view oi the chair shown in Fig.1, taken on line 1-2 of Fig. 1,

Fig. 3 is a fragmentary side elevational view of a different embodiment of an adjustable chair,

Fig. 4 is a sectionalv view of the chair shown in Fig. 3, taken online 4-4 of Fig.. 3,

Figs. 5 and. 6 are side elevational views of two:

' further. embodiments. of an adjustable chair according to the invention,

Fig. '7 is aside elevational view of still another embodiment of anadjustable chair'according to the inventions r Fig. 8 isa fragmentary front elevational view of. the backer-est of the chair shown in Fig; 7-;

I partly in section,

indicates asupporting flame-carriedby a. threaded, spindle 22, which. may besscrewed into a threaded mediate point of. saidback-rest, said seat being normally in a substantially horizontal sitting po-- sition and being arranged for a tilting about its opening of a supportingpedestal (not shown in N indicates a seat, the front. l

Figs; l and 2'). portion'of which is' pivoted to the side bar-s26 and 28 of the supporting frame. 20 at so and 32.. The seat 24' may be tilted about the pivots- 30 and 32 1 from a substantially. horizontal sitting position shown in full lines inFig. 1 into a rearwardly inolined position Mr shown in dash lines or into a forwardly inclined position 24! shown in dot and dash lines. 34 indicates a back-rest, the lower portion of which is pivotally connected with the rear portion of the seat 24 by means of a transverse rod 36 extending through a transverse bore of the seat. 38 generally indicates guiding linkmeans, one end of which is pivoted to an intermediate point of the back-rest 34, the other end of which is pivoted to the supporting frame at a point, which is spaced from the front pivot of the seat 24 and is positioned in the front portion of the chair in a plane below the horizontal plane of said front pivot 30 of the seat. Thus, the intermediate point of the back-rest 34 is guided along a continuous circular path by said guiding link-means 38 during a tilting of the seat 24 about the pivot 36. When the seat 24 is tilted about the front pivot 36 from the sitting position into the rearwardly inclined position 24r the angle between the seat and the back-rest 34 is increased, and when the seat is tilted from the sitting position into the forwardly inclined position the angle between the seat and the backrest is decreased.

According to Figs. 1 and 2 the guiding linkmeans 38 comprises a substantially U-shaped rod 40 having its base 4] rotatably arranged in sleeves 42 and 44. Said sleeves 42 and 44 adjustably arranged in curved slots 46 and 4B of the side bars 26 and 28 are held in their position by nuts 50 and 52 screwed on a threaded portion of the sleeves for urging the collars 54 and 56 of the sleeves against the wall of the side bars 26 and 28. The ends 58 and 60 of the legs of the U-shaped rod 49 are bent toward the back-rest 34. The end 58 is rotatably arranged in a block 62 adjustably arranged in a slot 63 of the back-rest 34; the block 62 and the end 58 may be held in their adjusted position by means of a thumb-screw 64. Likewise, the end 60 is rotatably arranged in a block 66 adjustably arranged in a slot (not shown) of the back-rest 34; the block 66 and the end 60 may be held in the adjusted position by a thumb-screw 68. Obviously, the adjusting means 42, 44, 46, 48, 50, 52 and/or 62, 64, 66, 68 may be used for a preadjustment of the angle between the back-rest 34 and the seat 214 when the latter is in a certain position, for example in the sitting position. For example, if it is desired to reduce the angle between the back-rest and the seat, the block 62 and 66 may be brought from their intermediate position shown in Fig. 1 into an upper extreme position wherein they contact the upper end of the slots'of the back-rest. Of course, during a tilting of the seat 24 from the sitting position into a rearwardly inclined position or into a forwardly inclined position, said preadjusted angle between the back-rest and the seat is increased or decreased as described above. The above mentioned preadjustment of the angle between the back-rest and the seat also results in an adjustment of the degree of variation in the angle between the back-rest and the seat during a tilting of the seat. For example, the greater the distance between the pivotal connection 58 and the pivot 36, the larger the degree of variation in the angle between the back-rest and the seat during a tilting of the seat, and vice versa. Or, the nearer the pivotal connection 4| to the pivot 30, the smaller the degree of variation in the angle between the back-rest and the seat during a tilting of the seat, and vice versa.

As best shown in Fig. 2,. two torsional springs Ill and 12 are arranged around the base 4| of the U-shaped rod 46 between the side bars 26 and 28 of the supporting frame 20. One end 74 of the spring 72 passing througha hole in the collar 56 of the sleeve 44 is in engagement with a recess 76 of the side bar 28; the shape of said recess 76 corresponds to the shape of the slot 48. The other end 78 of the spring 72 is secured to an adjusting nut 88 screwed on a threaded portion of the base 4! and heldin its position by a locknut 82. Likewise, the end 84 of the spring 10 passing through a hole of the collar 54 of the sleeve 42 is in engagement with a recess (not shown) of the side bar2'6, and the end 86 of said spring'is secured to an adjusting nut 88 screwed on a threaded portion of the base 41 and held in its position by a lock-nut 96. Said torsional springs 18 ahd l2 counteract the load of the user of the chair and tend to urge the seat 24 into its extreme forwardly inclined position 24f, which is limited by adjustable belts 92 and 94 having their ends connected with the supporting frame 2!) and the seat 24 respectively. The adjusting nuts 88 and 88 serve to adjust the tension in the springs 10 and 72 in accordance with the load of the user of the chair, so that always the same extreme rearwardly inclined position 24r of the seat may be obtained irrespective of the weight of the person sitting on the chair.

A locking lever 96 keyed to the transverse rod 36 serves to lock the movable parts 24, 34, 38 of the chair in any adjusted position. As best shown in Fig. 2, the hub 98 of the lever 96 has a camshaped inner surface I08 cooperating with one side of the back-rest 34, and the end of the transverse rod 36 opposite the lever 96 carries a head I02 resting against the other sideof the backrest. If the lever 96 is depressed and turned in clock-wise direction as viewed in Fig. 1, the cam I00 causes a clamping of the back-rest against the seat, whereby the movable parts of the chair are locked. Of course, any other locking means may be used, if desired.

The above described adjustable chair may be used in the following manner: The tension in the springs 70 and 12 is adjusted by means of the adjusting nuts 80 and 88 to such a degree, that,

upon a release of the movable parts of the chair by a turning of the lever 96 in counter-clockwise direction, the springs and 72 hold the seat 24 in a substantially horizontal sitting position when the user of the chair sits in upright position. If the user of the chair wishes to relax and leans his body against the back-rest 34, the back-rest and the seat are moved against the action of said springs into a reclining position indicated by dash lines in Fig. 1. If the user of the chair leans his body forwardly for the performance of a certain work on a desk, for example, the springs 10 and 12 cause a movement of the seat and the backrest into the forwardly inclined position shown in dash and dot lines in Fig. 1. Owing to the decrease of the angle between the back-rest and the seat, the back-rest remains in contact with the back of the user of the chair for supporting same during said upward tilting of the seat. If desired, the movable partsof the chair may be locked in any suitable position by depressing the locking lever 96.

The principal parts of the chair shown in Figs. 3 and 4 correspond to that of the chair shown in Figs. 1 and 2 and do not need to be described in detail. The back-rest 34 is pivotally connected with the rear portion of the seat 24 at 36; the front portion of the seat 24 is pivoted to the sup port 20 at .32 and 34 respectively. One end of Stand '52. The torsional springs I and I2 acting on the guiding link-means 38 tend to urge the seat 24 into its uppermost position shown in full lines in Fig. 3; which is limited by the limiting means I04 arranged on each sideof the chair. According to the embodiment of the chair shown in Fig. 3 the .uppermost position of the tiltable seat 24 represents its sitting position. i Th seat cannot be tilted into a forwardly inclined posi-, tion, but it may be tiltedinto a rearwardly in-, clined position Mr shown in dash lines.

Each limiting means I04 consists of a toggle lever mechanism comprising two levers I06 and I08 pivotally connected with each other at I I 6.-

The lever I06 is pivoted to the seat at I I2 and the lever I06 is pivoted to the frame 20 at II4. A spring II6 stretched between the lever I08 and the frame 26 tends to draw the lever I08 against a stop I I8 mounted on the frame 20, so asto bring the levers I06 and I06 substantially in alignment as shown in full lines in Fig. '3. Said spreading position of the levers I06 and I08 limits the uppermost or sitting position of the seat 24.

As will be readily understood, the action of the 1 spring I I6 counteracts to a certain degree a downward movement of the seat 24, and the action of the spring I I6 must be overcome beforethe levers I06 and I08 may be swung out of their spreading position by a pressure exerted on the back-rest.

Therefore, a user of the chair sitting in upright position may rest with his back on the back-rest without causing a movement of the levers I06 and I08. In other words, the spring loaded toggle lever mechanism also acts as locking means holding the movable parts of the chair in the sitting position, and a special locking lever may be omitted. l H

On each side of the chair an extension I20 is secured to the lower portion of the back-rest 34. An adjustable actuating member or screw I22 screwed into the free end of the extension I20 15 arranged for cooperation with the lever I06 of the toggle lever mechanism. If the user of the chair wishes to relax and leans his back against the back-rest for exerting an increased pressure thereon, the actuating member I22 acts on the lever I06 and causes a swinging thereof in counter-clockwise direction after the overcoming of the action of the spring II6. Thus,- the tb gle lever mechanism is released and the movable parts of the chair may be brought intothe reclining position indicated by dash lines in Fig. 3. When the user of thechair brings his body again in upright position, the springs I0, 'I2'and II6 return the movable parts of the chair into the sitting position. toggle lever mechanism could be replaced by other means which may limit th sitting position of the seat and also may cause a,locking of the movable parts of the chair.

Fig. 5 illustrates the application of my new chair construction according to Fig. l to a chair which may be used by typists, switch-board oper- Of course, the-spring loaded estal I22. The front portion of the seat 24 is pivoted to the frame-20 at 32, and the back-rest 34 is pivoted to the rear portion of th seat 24 at 36. The movement of theback-rest is controlled by guiding link-means 38 pivotally con= nected with the frame 20 and the back-rest 34. The spring I2 tends to urge the seat 24 upwardly into its uppermost position limited by the adjustable limiting belt 92.: The locking lever 96 serves to lock the movable parts of the chair in any adjusted position. The back-rest 34 carries an adjustable head-rest I24. P According to the embodiment shown in Fig. 6, the guiding link-means form the arm-rests I26 of a desk chair. One end of each arm-rest is pivoted to the supporting fram 20 at I26, the other end of each arm-rest is pivoted to an intermediate point of the. back-rest 34 at I30. The pivotal connections between the arm-rests and the frame and between the arm-rests and the back-rest are not adjustable in this embodiment of a chair. The back-rest 34 is pivoted to the seat 24 at 36, and the seat is pivoted to the frame 26 at 32. The spring I2 tends to urge the seat 24 into its uppermost position limited by a stop I32 arranged on the seat for cooperation with a bar of the frame 23. The locking lever 96 serves to lock the parts of the chair in an adjusted position. I Figs. 7 and 8 illustrate a different type of a chair having. a support I34 formed of tubular material. Said support'l34 carries a bracket I36 arranged substantially in the middle of the chair. The front portion of the seat I36 is pivoted to the support I34 at I40, and the rear portion of the seat is pivotally connected with the back-rest I42 at I44. The chair has only a single guiding 11m; 14s arranged in the middle of the chair.

ators, etc The spindle 22 carrying the supporting frame 20 is screwed into a conventional ea- One end of the link I46 is pivotally arranged in a slot I48 of the bracket I36, and the pivotal connection between the link I46 and the bracket I36 may be held in the adjusted position in the slot I48 by means of an adjusting nut I30. The other end of the guiding link I46 is connected with a transverse rod I52. Each end of said transverse rod I52 is pivotallymounted in a block I54 'slidably and adjustably arranged in a slot- I56 of the back-rest I42. The block I54 may be held in an adjusted position by means of a thumbscrew I58. ends secured to, the bracket I36 and the seat I38 tends to urge the seat I38 into the sitting position shown inFig. 7. Furthermore, said spring I60, if expanded, limits the sitting position of the seat, so that the latter cannot be tilted further upward. A locking lever I62 connected with a suitable locking mechanism (not shown) serves to lock the movable parts of the chair in anyv adjusted position. 1

Fig. 9illustrates the application of my chair construction to an arm-chair. The front portion of the seat I64 is pivoted to the front wall I66 of the support I68 at H0. The back-rest I12 is pivoted to the rear portion of the seat I 64 at I14. A guide link I16 is arranged on each side of the.

chair. One end of each guide link I16 is pivoted to the support I68 at I18, the other end of each guide link is pivoted to the back-rest at I86.

An S-shaped spring I66 having its :4 I least a portion of said guide links may be an seat into its uppermost sitting position limited by the spring I 86 if expanded. Instead of a single spring I86 several springs may be arranged next to each other, if desired. The movable parts of the chair may be locked in their adjusted position by means of a locking nut I92 screwed on a pin I94, which is secured to the seat I64 and passes through a curved s'lot I96 of the side wall 532.

The construction of the chair shown in Fig. differs from that shown in Fig. l in the embodiment of the adjustable guiding link means and in the arrangement of the torsional spring.

The chair according to Fig. 10 has two guiding link-means I98, one on each side of the chair. Each guiding link-means comprises a hollow rod 280 pivoted to the frame 20 at 202 and a rod 294 pivoted to the back-rest 34 at 206. The rod 204 is shiftably inserted into the free end of the hollow rod 289 for a variation in the length of the guiding link-means I98 and may be held in its position by an adjusting screw 2518. It will be readily understood that an adjustment of the length of the guiding link-means I68 results in a preadjustment of th angle between the backrest 34 and the seat 24. The torsional spring 2I I! is arranged in such a manner, that it acts directly on the seat 24 for tilting same upwardly about the pivot 30. The uppermost position of the seat is limited by the adjustable belt 92, and the locking lever 96 serves to lock the movable parts of the chair in an adjusted position.

As pointed out above, the back-rest of the chair according to the invention remains in contact with the back of the user of the chair during an adjustment of the movable parts of the chair from the sitting position into an inclined position and vice versa. According to a preferred embodiment of my invention I arrange the pivot point 38 (see Fig. 10 for example) between the backrest 34 and the seat 24 at a point spaced from the front surface of the main portion of the back-rest at a distance a of about 3 inches toward the front portion of the seat, whereby a relative movement between the back-rest and the back of the user is avoided during a swinging movement of the back-rest as the pivot point is substantially in the same plane as the hip-joint of the person sitting on the chair, Of course, it is understood, that this spacing of the pivot point between the back-rest and the seat from the front surface of the main portion of the back-rest may be applied to other chair constructions which do not comprise the tiltable arrangement or the seat and/or the guiding link-means shown in the drawings.

I have described preferred embodiments of my invention, but it is clear that numerous changes and omissions may be made without departing from the spirit of my invention.

What I claim is:

1. An adjustable. chair comprising: a support, a seat, a back-rest, the front portion of said seat being pivoted to said support at a stationary point, the back-rest being pivoted to the rear portion of said seat, guiding link-means, one end of said guiding link-means being pivoted to said support at a point positioned in the front portion of the chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to an intermediate point of said back-rest, said seat being normally in a substantially horizontal sitting position and being arranged for a tilting about its front pivot from said sitting position into a rearwardly inclined position and into a forwardly inclined position, said intermediate point'of the back-rest being guided along a circular path by said guiding means during a tilting of said seat whereby the angle between the seat and the backrest is increased when the seat is tilted from the sitting position into the rearwardly inclined position and whereby said angle is decreased when the seat is tilted from said sitting position into the forwardly inclined position, resilient means arranged between said support and a movable part of the chair for urging said seat into said forwardly inclined position, and limiting means connected with the seat and arranged for cooperation with said support for limiting the forwardly inclined position of the seat.

2. An adjustable chair as claimed in claim 1 including adjustable guiding link-means for a preadjustment of the relative position between the back-rest and the seat.

3. 'An adjustable chair as claimed in claim 1 including means for effecting adjustment of the pivotal connections between the guidinglinkmeans and the support and between the guiding link-means and the back-rest for a preadjustment of the relative position between the backrest and the seat.

4. In combination with an adjustable chair as claimed in claim 1, said support having a slot, and said back-rest having a slot, the pivotal means of said guiding link-means being engaged with said slots, and adjusting means for holding the pivotal means of the guiding link-means in an adjusted position in said slots for a preadjustment of the relative position between the backrest and the seat.

5. An adjustable chair as claimed in claim 1 including guiding link means of variable length, and means for adjusting the length of said guiding link-means for a preadjustment of the relative position between the back-rest and the seat.

6. An adjustable chair comprising: a support, a seat, a back-rest, the front portion of said seat being pivoted to said support, the back-rest being pivoted to the rear portion of said seat, guiding link-means, one end of said guiding linkmeans being pivoted to said support at a point positioned in the front portion of the. chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to an intermediate point of said back-rest, said seat being normally in a substantially horizontal sitting position and being arranged for a tilting about its front pivot from said sitting position into a rearwardly inclined position and into a forwardly inclined position, said intermediate point of the back-rest being guided along a circular path by said guiding means during a tilting of said seat whereby the angle between the seat and the back-rest is increased when the seat is tilted from the sitting position into the rearwardly inclined position and whereby said angle is decreased when the seat is tilted from said sitting position into the forwardly inclined position, spring means arranged between said support and said guiding link-means for urging said seat into said forwardly inclined position, and limiting means connected with the seat and arranged for cooperation with said support for limiting the forwardly inclined position of the seat.

7. An adjustable chair comprising: a support, a seat, a back-rest, the front portion of said seat being pivoted to said support, the back-rest being pivoted to the rear portion of said seat, guiding link-means, one, end of said? guiding I link-means being pivoted to said support at a point positioned in the front portion of the chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to anintermediate point of said back-rest, said seat being'normally in-a substantially horizontal sitting position and being arranged for a tilting about its front pivot from said sitting position into 'a rearwardly inclined position and into a forwardly inclined position, said intermediate point of the back-rest being guided along a circular path by said guiding means during a tilting of saidseat whereby the angle between the seat and the back-rest is increased when the seat is tilted from the sitting position into the rearwardly inclined position and whereby said angle isdecreasedwhenthe seat is tilted from said sitting position into the forwardly inclined position, Spring means arrangedb-etween said support and said guiding link-means for urging said seat into saidforwardly inclined position, adjusting means for an adjustment of the tension in said spring means, and limiting means connected with the seat and arranged for cooperation with the supportv for limiting the forwardly inclined position of the seat. I

8. An adjustable chair as claimed in claim 6 including torsional spring means "associated withthe pivotal connection between the guiding linkwhen the levers of the togg e-lever mechanism are substantially in alignment, and releasing means projecting from said-fback-rest for 00-. operation with the toggle. lever mechanism so as to release same. when. the back-rest is pressed rearwardly.

14. An adjustable chair comprising: a support, a seat, a. back-rest, the front portion of said seat being pivoted to said support, the back-rest being pivoted to the rear portion of said seat, guid-.,

ing link-meanaone end ofsaid guidinglinkmeans being pivoted to .said support at a point positioned in the front portion of the chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to an intermediate pointlof said back-rest, said seat being arranged for a tilting'about its front pivot from a sub-- stantially horizontal sitting position into an extreme. reclined position, saidintermediate point of the back-rest being guided along a circular path by said guiding means during a tilting of said seat whereby the angle betweenthe seat and the back-rest is increased when the seat is tilted from the sittingv position into the reclined position, torsional spring means associated with means and the support for urging said seat into 4 said forwardly inclined position.

9. An adjustable chair as claimed in claim 1,

including adjustable guiding link-means for an adjustment of the relative position between the back-rest and the seat and spring means arranged between saidsupport and said guiding. link-means for ur ing. said seat into said forthe horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to an intermediate point of said back-rest, said seat being arranged for a tilting about its front pivot from a substantially horizontal sitting position into an extreme reclined position, said intermediate point of the back-rest the pivotal connection between the guiding link! means and the support for urging said seat into said sitting position,a toggle lever. mechanism arranged between said seat and said support, a

spring stretched between said support and said I toggle lever mechanism forurging the levers,

, thereof into a spreading. position,.- said toggle lever mechanism locking said seat in its sitting position when the levers of the toggle leverimechanism are substantially inalignment, and releasing means projecting from said back-rest for cooperation with the toggle lever mechanism so as to release same when the back-rest is pressed rearwardly. v l

15'. An adjustable chair comprising: a support,

a seat, a back-rest, the front portion of said seat being pivoted to said support, the back-rest being pivoted to the rear portion of said seat,

being guided along a circular path bysaid guiding means during a tilting of said seat whereby the angle between the seat and the back-rest is increased when the seat is tilted from the sittin position into the reclined position, resilient means arranged between said support and a movable part of the chair for urging said seat into said sitting position, and a toggle lever mechanism arranged between said seat and said support for limiting the sitting position of the seat.

1 An adjustable chair as claimed in claim 11 including a spring stretched between said support and. said toggle lever mechanism for urging the levers thereof into a spreading position limiting the sittin position of'the seat.

13. In combination with an adjustable chair as claimed in claim 11, said toggle lever mechanism locking said seat in its sitting position guiding link-means, one end of said guiding linkmeans being pivoted to said support at apoint positioned in the front portion of the chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to an intermediate point of said back-rest, said seat being arranged for a tilting about its front pivot from a substantially horizontal sitting position into an extreme reclined position, said intermediate point of the back-rest being guided along a circular path by said guiding means during a tilting of said seat whereby the angle between the seat and the back-rest is increased when the seat is tilted. from the sitting position into the reclined position, and a spring arranged between the support and the seat for urging the seat into its sitting position and limiting said sitting position.

16. An adjustable chair comprising: a support, a seat, a back-rest, thefront portion of said seat being pivoted to said support, the back-rest being pivoted to the rear portion of said seat, guiding link-means, one end of said guiding linkmeans being pivoted to said support at a'pointpositioned in the front portion of the chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to an intermediate point of said back-rest, said guiding link-means being adjustable for a preadjustment of the relative position between the back-rest and the seat, said seat being arranged for a tilting about its front pivot from a substantially horizontal sitting position into an extreme reclined position, said intermediate point of the back-rest being guided along a circular path by said'guiding means during a tilting of said seat whereby the angle between the seat and the back-rest is increased when the seat is tilted from the sitting position into the reclined position, spring means arranged between said support and a movable part of the chair for urging said seat into said sitting position, and limiting means connected with the seat and arranged for cooperation with the support for limiting the sitting position of the seat.

17. In combination with an adjustable chair as claimed in claim 16, said support having a slot, and said back-rest having a slot, the pivotal means of said guiding link-means being engaged with saidvslots, and adjusting means for holding the pivotal means of the guiding link-means in an adjusted position in said slots for a preacljustment of the relative position between the back-rest and the seat.

18. An adjustable chair comprising: a support, a seat, the front portion of said seat being pivoted to said support, a back-rest pivoted to the rear portion of said seat, the pivot point between the back-rest and the seat being spaced from the front surface of the main portion of the backrest at a distance of about 3 inches toward the front portion of the seat, guiding link-means, one end of said guiding link-means being pivoted to said support at a point positioned in the front portion of the chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link-means being hinged to an intermediate point of said back-rest, said seat being arranged for a tilting about its front pivot from a substantially horizontal sitting position into an extreme reclined position, said intermediate point of the back-rest being aseazoo guided along a circular path by said guiding means during a tilting of said seat whereby the angle between the seat and the back-rest is in-,

creased when the seat is tilted from the sitting position into the reclined position, resilient means arranged between said support and a movable part of the chair for urging said seat into said sitting position, and limiting means connected with the seat and arranged for cooperation with the support for limiting the sitting position of the seat.

19. An adjustable chair comprising: a support, a seat, a back-rest, the front portion of said seat being pivoted to said support, the back-rest being pivoted to the rear portion of said seat, guiding link-means of variable length, one end of said guiding link-means being pivoted to said support at a point positioned in the front portion of the chair in a plane below the horizontal plane of said front pivot of the seat, the other end of said guiding link means being hinged to an intermediate point of said back-rest, means for adjusting the length of said guiding link-means for a preadjustment of the relative position between the back-rest and the seat, said seat being arranged for a tilting about its front pivot from a substantially horizontal sitting position into an extreme reclined position, said intermediate point of the back-rest being guided along a circular path by said guiding means during a tilting of said seat whereby the angle between the seat and the back-rest is increased when the seat is tilted from the sitting position into the reclined position, resilient means arranged between said support and a movable part of the chair for urging said seat into said sitting position, and limiting means connected with the seat and arranged for cooperation with the support for limiting the sitting position of the seat.

ANTON LORENZ.

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