US3120942A

US3120942A - Chair control

Info

Publication number: US3120942A
Application number: US112040A
Authority: US
Inventors: Robert H Savage
Original assignee: Knoll Associates Inc
Current assignee: Knoll Associates Inc
Priority date: 1961-05-23
Filing date: 1961-05-23
Publication date: 1964-02-11
Anticipated expiration: 1981-02-11

Description

Feb. 11, 1964 R. H. SAVAGE 3,

CHAIR CONTROL Filed May 23, 1961 2 Sheets-Sheet 1 lilllbllHIf llll INVENTOR. Pas/5K7 /7. 541 465 R. H. SAVAGE CHAIR CONTROL Feb. 11, 1964 2 Sheets-Sheet 2 Filed May 23, 1961 INVENTOR. 05527 541/465 BY United States Patent Ofiice 3,129,942 Patented Feb. 11, 1964 3,120,942 CH CONTROL Robert H. Savage, Schwenksville, Pa, assignor to Knoll Associates, inc, New York, N.Y., a corporation of New Yorlr Filed May 23, 196i, Ser. No. 112,040 4 (Ilairns. (Cl. 248374) The present invention relates to tension control mechanism for use in tilting chairs.

Heretofore the tilting mechanisms for chairs have, for the most part, employed coil springs or rubber torsion sleeves for supporting and controlling the tilting movement, and various means have been employed for adjusting the tension of the spring device of such prior mechanisms. Whatever the merit of the prior means, they all have in common openly exposed lever mechanisms and hand wheels through which the tension of the spring devices is adjusted.

The above described prior devices have not been entirely satisfactory for the reason that they quickly accumulate dust and dirt which is difiicult to remove, particularly from exposed surfaces to which grease or oil has been applied to ease their operation. Furthermore, the prior devices seldom were in harmony with the appean ance of the chair to which they were applied.

The mechanical design of the prior tension control devices resulted solely from the utilitarian requirements imposed on them. Little thought has been given heretofore to the visual as well as the mechanical aspects of chair tension devices. The art or" chair design has been one of rapid development, yet the best designs are often less effective because they must be used with chair control mechanism which is entirely unharrnonious therewith.

It is, therefore, an object of this invention to provide a chair tension control mechanism which has tension adjusting elements that are entirely enclosed and, therefore, concealed from view.

It is a further object of this invention to provide a chair control device which is far more compact than previously believed possible.

it is still another object of this invention to provide a chair tension control device which has improved tension adjusting means, and which can be positively operated with the greatest ease in adjusting the tilting tension of the chair.

The full nature and purpose of these and other objects and advantages of the invention and their attainment, will be clear from a reading of the following description in light of the drawings. In the drawings, like reference numerals indicate like parts, and:

FIG. 1 is a side elevational view of a chair in which the chair tension regulating mechanism herein is installed; FIG. 2 is a front elevational view of the mechanism;

FIG. 3 is a top plan view;

REG. 4 is a sectional view on the line 44 of PEG. 2;

FIG. 5 is a sectional view on the line 5-5 of FIG. 4; and

FIG. 6 is a fragmentary view showing the manner in which a torsion element is locked to a bracket casting.

A specific embodiment of my chair tension regulating mechanism includes a bracket casting ill to which the usual chair spindle 12 is firmly attached, and a chair base casting 14 to which the seat is of a chair is attached. These two castings, when assembled, are adapted to tilt in respect to each other on a horizontal axis and they provide an enclosure for the elements of the tension control mechanism. A torsional joint 18 interconnects the bracket casting and the base casting coincident with the horizontal tilting axis. The torsional joint consists of an inner sleeve 29 connected to the base casting 14 for rotation therewith, a spaced concentric outer sleeve 22 rotatably carried by the bracket casting 1d and a torsion element 24 of the elastic material disposed between the

sleeves

20 and 22. The torsion element 24 is held between the

sleeves

20 and 22 under substantial compression and it is bonded to the sleeves against rotation in respect thereto as shown, for example, in United States Patent 2,087,254 to Walter F. Herold. Finally, a worm gear sector 26 is connected to the outer sleeve 22 of the torsional joint and a worm 2?; is mounted in the bracket casting It in operative relation to the worm gear sector 26 by which the outer sleeve 22 of the torsional joint is cfiectively connected to the bracket casting ill. The bracket casting is formed with an upwardly flared face 3t) in which there is formed a downwardly opening cavity 32 which is adapted to receive and substantially enclose the worm 28.

The base casting 14 is a generally annular member providing a flat surface 34 to which the chair seat 16 is attached. It includes oppositely located depending skirts 36 and 33 in which stay bolt passages 40' and 42 are formed. A stay bolt 44 extends through the stay bolt passages 4t and 42 and through the inner sleeve 26 of the torsional joint, thus holding the elements assembled and providing an axis on which the seat of the chair can tilt.

The base 14 provides an open lower face in which the upper end of the bracket in is seated where it, together with the torsional element 18, is positioned between the depending

skirts

36 and 38 of the base 14.

The bracket 16 at its upper end has a pair of

mounting collars

46 and 48 adapted to snugly embrace the tersional joint 13 while its lower end terminates in a neck 58, having a spindle socket 52 into which the chair spindle 12 is fastened.

The inner sleeve 2d of the torsional joint 18 has formed in the opposite ends thereof

locking grooves

54 and 56. These grooves are preferably formed along the vertical diameter of the sleeve. A complementary pair of lock ribs 58 and 69 are formed in the confronting faces of the depending skirts 36 and 33 and project toward each other to provide means by which the inner sleeve 20 of the torsional joint 18 will be locked against rotation when the

grooves

54 and 56 of the sleeve are in engagement, respectively, with the lock ribs 58 and 6d. The lock ribs 58 and 6t) are formed along an extension of the vertical diameter of the stay bolt passages 40' and 4-2.. Therefore, when the torsional joint 13 is put into place between the depending

skirts

36 and 38 of the base 14 with the lock ribs 58 and so engaged respectively in the grooves $4 and 56 of the inner sleeve 29, the inner sleeve will be held immobile in the base casting.

The stay bolt passage 4t? is countersunk to receive the head 62 of the stay bolt 44, while the passage 42 has screw threads 64 formed therein to engage corresponding screw threads 66 on the opposite end of the stay bolt.

Fixed to the outer sleeve 22 of the torsional joint by means of a set screw 68 is a gear sleeve 7% which has formed in the face thereof the worm gear sector 25. The worm 28 is mounted in an inwardly projecting lip '72 at the front of and near the upper end of the case 14. This places the worm 28 into operative engagement with the worm gear sector 26, such that when the worm 28 is turned on its shaft 74, it will turn the gear sleeve 70 and with it the outer sleeve 22 of the torsional joint 13. Turning of the worm on its shaft 74 adjusts the torque imposed on the elastic 24 of the joint and, therefore, increases or decreases the resistance of the chair to tilting, depending on the direction in which the worm 28 is rotated.

The annular chair supporting surface 34, as best seen in FIG. 3, is an inwardly extending flange through which extend a plurality of screw holes 76. The base 14 is first attached to the chair seat 16 preferably with an interposed mounting plate '78 which has a corresponding number of screw holes located at points coinciding with the screw holes '76 of the base flange. it will be noted that the attaching screws by which the base 14 is attached to the chair seat are disposed within the annulus of the casting and are, therefore, externally invisible.

The annular flange 34 of the base has a slot 36 formed therethrough which permits the casting to yield somewhat, if necessary, during the assembling operation.

The outer contour of both the bracket and the base 14 are generally conical and the major external surface area of the castings, when assembled, are in continuation of each other along these generally conical lines, such that the overall effect of the assembly is that of an inverted, truncated cone.

The invention, therefore, provides a mechanism which is compact, visually pleasing and easy to keep clean. Furthermore, all of the operating elements are effectively enclosed within the castings such that the pleasing external appearance of the mechanism is maintained.

In operation, the chair, when fitted with the mechanism herein, can be tilted rearwardly against the tension of the torsional joint 13, increasing the torque on the joint as the chair is tilted rearwardly. A stop 82 formed as an inwardly extending lip at the back of the base 14 is adapted to engage an abutment 34 on the bracket 19' to limit 'the extent to which the chair can be tilted backwardly.

In order to adjust the mechanism to provide less or greater resistance to the tilting motion, it is merely necessary to rotate the Worm. 28 in the proper direction to place the elastic torsion member 24 under more or less torque.

While the novel features of the invention have been illustrated and described in connection with a specific embodiment of the invention, it is believed that this embodiment will enable others skilled in the art to apply 7' the principles of the invention in forms departing from the exemplary embodiment herein, and such departures are contemplated by the claims.

What is claimed is:

1. A chair iron comprising a base casting in the form of an inverted truncated cone, a pair of oppositely disposed bearing skirts constituting a horizontal tilting axis in said base casting, a hollow bracket casting formed generally in external continuation with the external contour of said base casting and seated between said bearing skirts, a torsional joint interconnecting said bracket casting and said base casting connected with said horizontal tilting axis, said torsional joint comprising a first sleeve connected to said base casting, a spaced concentric second sleeve connected to said bracket casting, and a torsional element of elastic material disposed between said sleeves and joined to said sleeves against rotation in respect thereto, a worm gear sector connected to the outer or" said sleeves within said base casting, a cavity opening downwardly in the wall of said bracket casting, a worm mounted in said cavity in operative relation to said worm gear sector, said cavity extending through the Wall of said bracket casting providing contact between said worm gear sector and said worm, a worm mounting shaft seated for rotation in said cavity, and a worm operating shaft within said cavity, said torsional joint, said gear sector and said worm being substantially enclosed within said castings.

2. The combination defined in claim 1, in which the base of said base casting is in the form of an annular member adapted to support the seat of a chair.

3. The combination defined in claim 2, in which said annular member of said base casting has a slot formed thereth-rough to impart thereto a limited yielding characteristic.

4. The combination defined in claim 1, in which said cavity extending through the Wall of said bracket casting terminates in an inwardly projecting lip and said worm operating shaft is mounted for rotation in said lip.

References Cited in the file of this patent UNITED STATES PATENTS 2,087,253 Herold July 20, 1937 2,087,254 Herold July 20, 1937 2,894,562 Peller July 14. 1959

Claims

1. A CHAIR IRON COMPRISING A BASE CASTING IN THE FORM OF AN INVERTED TRUNCATED CONE, A PAIR OF OPPOSITELY DISPOSED BEARING SKIRTS CONSTITUTING A HORIZONTAL TILTING AXIS IN SAID BASE CASTING, A HOLLOW BRACKET CASTING FORMED GENERALLY IN EXTERNAL CONTINUATION WITH THE EXTERNAL CONTOUR OF SAID BASE CASTING AND SEATED BETWEEN SAID BEARING SKIRTS, A TORSIONAL JOINT INTERCONNECTING SAID BRACKET CASTING AND SAID BASE CASTING CONNECTED WITH SAID HORIZONTAL TITING AXIS, SAID TORSIONAL JOINT COMPRISING A FIRST SLEEVE CONNECTED TO SAID BASE CASTING, A SPACED CONCENTRIC SECOND SLEEVE CONNECTED TO SAID BRACKET CASTING, AND A TORSIONAL ELEMENT OF ELASTIC MATERIAL DISPOSED BETWEEN SAID SLEEVES AND JOINED TO SAID SLEEVES AGAINST ROTATION IN RESPECT THERETO, A WORM GEAR SECTOR CONNECTED TO THE OUTER OF SAID SLEEVES WITHIN SAID BASE CASTING, A CAVITY OPENING DOWNWARDLY IN THE WALL OF SAID BRACKET CASTING, A WORM MOUNTED IN SAID CAVITY IN OPERATIVE RELATION TO SAID WORM GEAR SECTOR, SAID CAVITY EXTENDING THROUGH THE WALL OF SAID BRACKET CASTING PROVIDING CONTACT BETWEEN SAID WORM GEAR SECTOR AND SAID WORM, A WORM MOUNTING SHAFT SEATED FOR ROTATION IN SAID CAVITY, AND A WORM OPERATING SHAFT WITHIN SAID CAVITY, SAID TORSIONAL JOINT, SAID GEAR SECTOR AND SAID WORM BEING SUBSTANTIALLY ENCLOSED WITHIN SAID CASTINGS.