FITTING IN A CHAIR

Abstract: A fitting which is adapted to be mounted on a chair having a leg element, a seat (5) and, arranged therebetween, an upright column element (1), comprises a horizontal inner tube (11) and an outer tube (13) extending in parallel with the inner tube (11) and rotatably mounted thereon. The inner tube (11) is provided with an inner mounting (12) for the column element (1). The outer tube (13) is formed with a bottom opening (16) for the column element (1), and means (6, 7) for mounting the fitting (10) on the seat (5) of the chair. Locking means (28-36) is arranged for releasably locking the outer tube (13) in any desired rotational position relative to the inner tube (11).

Description: FITTING IN A CHAIR The present invention relates to a fitting adapted to be mounted on a chair having a leg element, a seat and, arranged therebetween, an upright column element. Ordinary office chairs are individually adjustable, inter alia in respect of the height and inclination of the seat. Moreover, it is often possible to rock the seat, for which an elastic balancing member is used to balance the resulting forces. Usually, the balancing member is also individually adjustable to the user's weight. The means for carrying out the above-mentioned adjustments as well as the adjustment of the inclination and height of the back of the chair and the adjustment of arm-rests, if any, make the frame of modern office chairs highly complicated and aesthetically not very attractive. Besides, the different types of gas-driven springs, tor¬ sion bars etc. which are used take up a great deal of space and are difficult to keep clean since they are uncovered and consequently collect dust. The object of the invention is to provide a compact fitting which in spite of a simple and smooth outer shape can contain at least one of the functions which are required for individual adaptation and desired for com- fort. This object is achieved by means of a fitting which is characterised by a horizontal inner tube having an internal mounting which is arranged to be connected with the upper end of the column element, an outer tube arrang- ed in parallel with the inner tube and rotatably mounted thereon, the outer tube having a bottom opening formed directly opposite the mounting in the tube wall and intended for the column element, and means for mounting the fitting on the seat of the chair, and locking means for releasably locking the outer tube in any desired rota¬ tional position relative to the inner tube. A preferred embodiment of the invention will be described in more detail below with reference to the accompanying drawing in which: Fig. 1 is a longitudinal section of a fitting, Fig. 2 illustrates the fitting in Fig. 1 as seen from the right end and with the cover removed, and Fig. 3 shows the fitting in Fig. 1 from the left end and with the cover removed. The fitting 10 illustrated in the drawing comprises a horizontal inner tube 11 having an internal vertical sleeve 12 inserted in diametrically opposed openings in the inner tube wall with which the sleeve is fixedly con¬ nected. The sleeve 12 is open in both ends, tapers coni- cally from below and upwards and is adapted to receive, in a form-fit manner, the end of a piston 2 which is included in the column element 1 of an office chair. The piston 2 is displaceably mounted in a gas-filled cylinder and can, for displacement, be released by means of an insertable valve rod 3 at the top of the piston. The inner tube 11 is concentrically surrounded by an outer tube 13 which is rotatably mounted on the inner tube by means of slide bearing tracks 14, 15. The outer tube is formed with openings 16, 17 in alignment with the sleeve 12, the opening 16 having the shape of an oblong hole to facilitate rotation of the outer tube 13 about the sta¬ tionary inner tube 11, with the piston 2 inserted. The top opening 17 is arranged first of all for maintenance pur¬ poses. To the right and left in Fig. 1, the outer tube 13 is, at the top, formed with brackets 6, 7 which are fixed¬ ly connected to the wall of the outer tube 13 and support the seat 5 of the office chair. The ends of the outer tube 13 are fitted with circu¬ lar covers 18, 19 which by means of circumferential flanges enclose part of the wall of the outer tube 13. In the manner described below, the covers 18, 19 are connect¬ ed with the inner tube 11 and arranged in a loose-fitting manner on the outer tube 13 which is thus rotatable rela¬ tive to the covers 18, 19. In the upper part of the inner tube 11, a shaft 20 is arranged, extending in parallel with the common longitu- dinal axis A of the two tubes 11, 13 and through diame¬ trically opposed openings in the sleeve 12 above the pis¬ ton 2 inserted in the sleeve 12. To the left of the sleeve 12, the shaft 20 has a journal 21 supported in a vertical strut 22 which is fixedly connected with the inner tube 11. To the right of the sleeve 12 there is a second, ver¬ tical strut 23 which is also fixedly connected with the inner tube 11 and forms a bearing point for the shaft 20. The right end of the shaft 20 projects from an opening in the cover 19 and is adapted to be connected to an operat- ing lever (not shown) for rotating the shaft 20. Directly opposite the projecting valve rod 3 of the piston 2, the shaft 20 is formed with a recess 24 which has a flat bottom facing the valve rod 3. As long as the bottom of the recess 24 is positioned horizontally, the valve rod 3 is not activated, i.e. the piston 2 is locked in the cylinder of the column 1, but if the shaft 20 is rotated by means of the associated operating lever in any direction, the bottom surface of the recess 24 depresses the valve rod 3 which then, for vertical adjustment, releases the piston 2 in the cylinder of the column 1. When the vertical adjustment is completed, the operating lever is released and the shaft 20 rotated back to the starting position for locking the piston 2. On the right-hand strut 23 there is a mounted a pin 25 which is concentrically arranged between the two tubes 11, 13 and nonrotatable relative to the inner tube 11. The pin 25 projects beyond both the outer tube 13 and the inner tube 11 which is shorter than the outer tube 13, and forms at its outer, right end a shoulder extending perpen- dicular to the pin 25 and having a central threaded pro¬ jection 26. The right-hand cover 19 engages the shoulder and is formed with a central opening for the projection 26 and screwed to the shoulder by means of a domed nut 27. The cover 19 is nonrotatable relative to the inner tube 11 owing to the shaft 20 which extends through its opening in the cover 19. Two substantially semicircular locking jaws 28, 29, which form a ring of approximately the same outer diameter as the inner diameter of the outer tube 13, are hingedly suspended from the shaft 20 to the right of the inner tube 11. The locking jaws 28 and 29 are biased towards one another by means of a tension spring 30 and are externally rubber-coated and formed with inwardly directed shoulders 31, 32 directly opposite the shaft 20. Between the shoul¬ ders 31, 32 and diametrically opposite the shaft 20, a shaft 33 extends in parallel therewith. The left end of the shaft 33 is fitted with a journal 34 which is sup¬ ported in the strut 23, and its right end is supported in a further opening in the right-hand cover 19 through which it extends to be connected, like the shaft 20, with a second operating lever (not shown). Adjacent the shoulders 31, 32 of the locking jaws 28, 29, the shaft 33 is formed with two opposite recesses 35, 36 which, as the shaft 33 is rotated from the position illustrated in Figs 1 and 2 in which the shoulders 31, 32 ride on the shaft 33 at the largest diameter thereof and the locking jaws 28, 29 are pressed against the inside of the outer tube 13, receive the shoulders 31, 32, the locking jaws 28, 29 being pressed together by the tension spring 30 and releasing the outer tube 13. To prevent, as the outer tube 13 is released, the seat 5 from falling forwards or backwards and to permit rocking of the seat, the outer tube 13 is provided at its left end with balancing means comprising a diametrical strut 37 whose large faces are perpendicular to the end of the outer tube 13, whereas its narrow faces extend in parallel therewith, the outer narrow face being flush with said end. The large faces of the strut 37 are surrounded by walls 38, 39 in a recess in the left end of the inner tube 11, in which recess the strut 37 is positioned. The walls 38, 39 extending in parallel with each other are also perpendicular to the end of the outer tube 13 and spaced from the strut 37. Between the strut 37 and the walls 38, 39, bodies 40, 41, 42, 43 of elastic plastics material are arranged, against which abut the large faces of the strut 37 and the walls 38, 39. When rotating the outer tube 13 relative to the inner tube 11, the elastic bodies 40-43 are deformed and always strive to reset the outer tube 13 and, conse¬ quently, the seat 5 to a predetermined starting position. When the locking jaws 28, 29 are released from the outer tube 13, this can, as mentioned above, be rotated relative to the inner tube 11. This occurs against the force which the elastic bodies 40-43 exert upon the strut 37 and the walls 38, 39. To permit adjustment of this force and, thus, also individual adaptation of the rock¬ ing function to the user of the chair, the strut 37 is provided with a central, axially orientated sleeve 44 through which a screw 45 is inserted from inside. The head of the screw 45 is a metal plate 46 bent in U-form, whose flanges project beyond the external sides of the walls 38, 39 to lock against rotation. The thread of the screw 45 projects through a central opening in the left- hand cover 18 of the fitting and is connected to a knob 47 which can be tightened against the cover 18 via two washers 48, 49 and an intermediate ball bearing 50. The elastic bodies 40-43 are clamped between the head of the screw 45 and the inside of the cover 18 and are thus com- pressed as the knob 47 is tightened. As a result, also the resistance increases, which the bodies 40-43 offer against the rotation of the outer tube. When loosening the knob 47, this resistance decreases correspondingly. Of course, the invention is not limited to the fit- ting described above, but may be freely modified.within the scope of the appended claims. For example, instead of the described balancing means and the elastic bodies 40-43, it would also be possible to choose a design including a torsion rod, and instead of nonrotatably mounting the covers 18, 19 on the inner tube 11, they could be connected to the outer tube 13 in some suitable manner, which in respect of the cover 19 would require arcuate, oblong holes for the two shafts 20 and 33. Instead of the described locking device of the drum-brake type, it would also be possible to choose a disc structure or a structure having elongate slots in one end of the wall of the inner tube 11, thereby forming flaps which may be expanded towards the inside of the outer tube 13 by expansion means. What the above-mentioned alternative structures have in common is that they are preferably designed so as to be contained within the outer tube 13 and inwardly of the covers 18, 19.

Claims: CLAIMS 1. Fitting adapted to be mounted on a chair having a leg element, a seat (5) and, arranged therebetween, an upright column element (1), c h a r a c t e r i s e d by a horizontal inner tube (11) having an internal mount¬ ing (12) which is arranged to be connected with the upper end (2) of said column element (1), an outer tube (13) extending in parallel with said inner tube (11) and rotat¬ ably mounted thereon, said outer tube having a bottom opening (16) formed directly opposite said mounting (12) in the tubular wall and intended for said column element (1), and means (6, 7) for mounting said fitting on the seat (5) of said chair, and locking means (28-36) for releasably locking said outer tube (13) in any desired rotational position relative to said inner tube (11). 2. Fitting as claimed in claim 1, c h a r a c ¬ t e r i s e d in that a cover (18, 19) which is nonrotat- ably connected to the inner tube (11) closes each end of said outer tube (13). 3. Fitting as claimed in claim 1 or 2, c h a r a c ¬ t e r i s e d in that said locking means (28-36) is designed as a drum brake and comprises locking jaws (28, 29) suspended from said inner tube (11) so as to cooperate with the inner wall of said outer tube (13) . 4. Fitting as claimed in any one of claims 1-3, c h a r a c t e r i s e d in that balancing means (37-43) is arranged to reset said outer tube (13) to a predeter- mined starting position, when the locking means (28-36) is released. 5. Fitting as claimed in claim 4, c h a r a c ¬ t e r i s e d in that the resetting force of said balanc¬ ing means (37-43) is adjustable by adjusting means (44-50). 6. Fitting as claimed in any one of claims 1-5, adapted to be mounted on a chair whose column element (1) is vertically adjustable by means of a gas-driven spring whose upper end is provided with an operating member (3), c h a r a c t e r i s e d by a rotatable operating shaft (20) extending in parallel with and supported in said outer tube (11) and having a cam surface (24) for coopera- tion with said operating member (3).

Inventors: BJOERNHOLM AAKE, GROSETH MORTEN, SPOERK CLAUS, BJOERNHOLM, AAKE, GROSETH, MORTEN, SPOERK, CLAUS
Applicants: LECTUS OFFICE AB
Application year: 1992
Main classification: A47C9
IPC codes: A47C3