AU643615B2 - A device for adjusting the inclination of seat-type furniture, typically office swivel chairs - Google Patents

Description

AUSTRALIA

6436 Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: A DEVICE FOR ADJUSTING THE INCLINATION OF SEAT-TYPE FURNITURE, TYPICALLY OFFICE SWIVEL CHAIRS.

The following statement is a full description of this invention, including the best method of performing it known to me:u o *f e oroo0• A DEVICE FOR ADJUSTING THE INCLINATION OF SEAT-TYPE FURNITURE, TYPICALLY OFFICE SWIVEL CHAIRS Specifications The invention relates to a device for adjusting the inclination of seat-type furniture, typically office swivel chairs, which has the characteristics described in the introductory clause of claim 1.

From European Patent No. 0 419 404 Al an office swivel chair is known which has a U-shaped member, whose arms are directed CAwuiward, and which possesses a seating recess at its back end to accept the support column of a cruciform base. At its front end the bearing member is stwivellably connected with the front enC of a seat-supporting member.

The bearing member and the seat-supporting member are swivellable in relation to one another, and means of adjustment are provided to adjust the positions of the o bearing member and the seat-supporting member.

In order to adapt the office swivel chair, equipped with this device for adjusting the chair's inclination, to accommodate persons of differing bodily weights, there is affixed an adjustable torsion spring device in the area where the bearing member and the seat-supporting member are connected.

Some adverse aspects of this arrangement using the torsion spring device however are; firstly, the fact that this arrangement, in a connection between the bearing member and the seat-supporting member, allows high leverage forces to act against these members, which occurs at the expense of I i 3 resistance to wear and tear, as well as at the expense of accuracy of adjustment. Over and above that, the construction is also a relatively expensive one, inasmuch as it involves the installation of a spring element, a torsion spring device and a pneumatic spring.

It is therefore the aim of the present invention to produce a device for adjusting the inclination of seat-type furniture, typically office swivel chairs, which works by means of a simple mechanism which is, as far as possible, not subject to wear and tear, and one in which adaptation to differing bodily weights can be carried out with precision.

This aim is accomplished by means of the features cited in the characterizing portion of Claim 1. Advanced designs and specialized design versions of the invention are covered in the remaining claims.

In terms of the invention the device proposed for the adjustment of the inclination of seat-type furniture has a longitudinally variable braking device, which is connected on its front end with the front end of a U-shaped bearing member, and at its back end with a means of adjustment.

The means of adjustment is attached between the arms of the bearing member, which can be directed upwards or downwards, and between the means of adjustment and the seat-supporting member there is affixed a transposition mechanism which is swivellable and projects through a recess in the crosspiece of the bearing member in order to alter the point of S."engagement on the braking device. The swivelling ranges between the bearing member and the seat-supporting member, and therefore the longitudinal variation of the braking device, are capable of being regulated by the means of adjustment.

The means of adjustment as per the invention, in its most advantageous form, is a threaded rod extending downward from the bearing member, which is freely rotatably seated at its upper end within a crossbolt that is rotatably seated between the arms of the bearing member. The transposition mechanism between the means of adjustment and the seat-supporting member consists, in its most advantageous form, of a connecting piece rotatably seated in the under side of the seat-supporting member and a guide piece rotatably connected to it which is, at its other end, connected slidably with the means of adjustment. The guide piece is connected with the crossbolt of the bearing member and extends further downward beyond the latter, in which, in this section, it has at least one slotted hold pointing downward. The braking device is connected with the threaded rod via a guide bolt which has a tapped hole for the threaded rod, in which system this guide bolt is rotatably seated in at least one bracket of the braking device directed toward the threaded rod. Laterally the guide bolt has at least one guide stud for the at least one slotted hole of the guide section.

The braking device may be a mechanical unit or a pneumatic spring unit, in which these units are capable of being locked into any possible position between their shortest and their longest extension stops, and in which the locking into position can be actuated by means of an adjusting lever, Bowden control cable, or the like, which extends outward laterally through or underneath the arm of the bearing member. It has proved to be advantageous, particularly where a mechanical spring, or a mechanical springing device, been attached, to provide some means of preventing a jerky tension release of this spring or springing device in order to stop the seat or the back rest from flying upward. The mechanical spring or pneumatic spring ought to have a curvilinear characteristic shape, in order that the longitudinal variation effected by the means of adjustment also results in a change in the tension of the spring.

The threaded rod can be actuated, either from below by means of an adjusting knob, or else from the side by means of an adjusting wheel which acts upon the threaded rod via a gear wheel drive. In this second design the threaded rod is extended upward through the crossbolt and connected there with a first gear wheel. The first gear wheel meshes with a second gear wheel which is affixed next to the guide section and offset by 900 from the first one. Either this second gear wheel, which is rotatably seated on the crossbolt, or else, in another design, a fourth gear wheel which is fastened next to the second gear wheel and along with it onto a bushing rotatably seated on the crossbolt, meshes into a third gear wheel further down below, which is rotatably seated in the arm of the bearing member, in which this third gear wheel projects outward with a bolt through the arm and is connected with the adjusting wheel. The lateral attachment of the adjusting wheel has the special advantage that it is always located at the same place, whereas the threaded rod, and therefore the adjusting knob, moves around the crossbolt and can be located at a different place each time depending on the setting installed.

The first and second gear wheels which mesh with one another are, in the most advantageous form, designed as bevel gear wheels. At least one of the gear wheels can, in each instance, have only one toothed segment within the required actuation sector, for which reason it should be restricted in its travel by means of a catch, for example.

In particular, if the threaded rod of the means of adjustment is designed to be without inherent nonreversibility, which is an advantage for making it easier to actuate, then a click-stop device should be installed between the third gear wheel and the arm through which the bolt that is connected with the adjusting wheel projects, a stop that can be actuated by means of the adjusting wheel.

This click-stop device can, for example, consist of at least one lug and a number of click-stop holes, in which case either the lug is affixed to the third gear wheel and the click-stop holes are located in the arm, or else the lug is affixed to the arm and the click-stop holes are located in the third gear wheel. In accordance with another design version of the invention the click-stop device consists of a clamping collet capable of being brought into engagement with the third gear wheel by means S"of the adjusting wheel. If a click-stop device is used S"then it is also more feasible to provide the adjusting wheel with an indicating device for the appropriate weights.

It has proved to be an advantageous feature if at least one •spring is affixed between the bearing member and the seatsupporting member, a spring which should be designed in such a way that it will support the weight of the seatsupporting member along with its upholstering and, where 30 required, that of any additional parts which are associated with it. In order not to have to manufacture different types of springs for different chair models it should be possible to attach the spring at various points between the bearing member and the seat-supporting member.

It has proved to be particularly advantageous if the connection of the bearing member with the seat-supporting member is made at their forward ends, but behind the place where the braking device is anchored to the bearing member.

In its end and start positions the means of adjustment locks the bearing member and the seat-supporting member to each other by the act of having the guide bolt pressed against the beginning or the end of the slotted hole.

Between the end and the start positions is the sector defined by the means of adjustment within which the seatsupporting member and the bearing member, braked by means of the braking device, can be swivelled (tilted) in relation to one another. The tilting can be arrested by means of locking mechanisms which act on the braking device, for example, in which process the seat-supporting member and the bearing member can be locked into any position located between the start and the end positions.

The locking mechanism can, however, also be made to act on the means of adjustment or on the transposition mechanism.

By turning the adjusting knob or the adjusting wheel the threaded rod is made to turn either directly or via a gear wheel drive, by which means the guide bolt, which is forcibly guided within the slotted hole via the the guide stud, is made to move along the length of this slotted hole. The guide section, within which the slotted hole is located, and which is rigidly connected with the crossbolt rotatably seated between the arms of the bearing member, plus a connecting piece swivellably attached to that section and rotatably mounted on the under side of the seat supporting member, constitute the transposition mechanism which, depending on the position at which the guide bolt is set and therefore where the one end of the braking device 4 J q 8 or the spring is located, leads to a different point of engagement on the braking device. By means of this arrangement it is possible, through the setting installed in the transposition mechanism and therefore the point of engagement on the braking device, to select the range within which the seat-supporting member and bearing member are tilted in such a way that varying degrees of force are required to induce tilting. In that way account can be taken of the varying bodily weights of the persons seated, in which process the positioning of the seat-supporting member vis-a-vis the bearing member, as well as the regulating of the tilting force, are accomplished via the braking device and the transposition mechanism.

In the following section the invention will be described in greater detail with the aid of drawings. These drawings illustrate the following: Fig. 1) A side view of an office swivel chair with the device as per the invention Fig. 2) A side view of the device for adjusting the tilt position as per the invention Fig. 3) A view of the device in accordance with Fig. 2) as seen from above Fig. 4) An illustration of the design of the devic as per the invention using the gear wheel drive F..ig. 5) A side view of the design in accordance with Fig. 4) Fig. 6) A view of a bearing member of a specially advantageous design version The office swivel chair 1 in accordance with Fig. 1) consists of a seating element 32 which is connected via a seat-supporting member 7 and a bearing member 2 to a support column 4 and a cruciform base 5. The device as per the invention for adjusting the inclination, consistir- of a braking device 8, a means of adjustment 9 and a transposition mechanism 14, is located within the area of the U-shaped bearing member 2, whose arms are directed downward, or between the latter and the seat-supporting member 7. In this illustration, furthermore, it is possible to recognize the connection 6 between the seatsupporting member 7 and the bearing member 2 which can, for example, be a bolt, around which the two members can be swivelled in relation to one another. Underneath the bearing member 2 there is located an adjusting knob 25 for actuating the device as per the invention. By turning the adjusting knob 25 a threaded rod 15 is turned simultaneously along with it which, in connection with the parts described re Fig. 2) and Fig. 3) further below, and the guide piece 18, and the associated crossbolt 16, and the connecting piece 17 to the seat-supporting member 7, which are still recognizable in this illustration, makes it possible to tilt the office swivel chair or lock it into S' position, in which pror.,ss the device can be adjusted to take into account the weight of the person using the chair.

To facilitate this it can be useful to design the braking device in the form of a spring with a curvilinear characteristic shape. The office swivel chair, nevertheless, can also be fixed into any position of the tilting range by using a laterally attached locking mechanism 44 which acts on the braking device 8 or the means of adjustment 9 or, where applicable, also or the 30 transposition mechanism 14.

Fig. 2) shows a simplified illustration of the bearing member 2, along with the seat-supporting member 7 and the device as per the invention. The bearing member 2 is Ushaped and consists of a crosspiece 13 with two arms 10, 11 directed downward, between which is affixed the braking device 8. The connection 6 between the seat-supporting member 7 and the bearing member 2 can, by way of example, be a bolt, which is rotatably seated in the arms 10,11 of the bearing member 2 and the downward directed arms or flanges of the seat-supporting member 7. The bearing member 2 is provided, at its back lower end, with a seating recess 3 for the support column. Elements of the device as per the invention which can be recognized here are the arrangement of the transposition mechanism 14, the guide piece 18 and the connecting piece 17. The connecting piece 17 is an elongated flat piece which is rounded off at the ends and rotatably affixed at the top, by means of a pin 35, to the under side of the seat-supporting member 7 between two downward directed flanges 33,34. Its flat side, and the direction of swivel, run parallel to the arms 10,11 of the bearing member 2. At its lower end the connecting piece 17 is rotatably seated, once again by means of a pin, between two flanges 39,40 of the guide Spiece 18. The guide piece 18, in its turn, is rotatably mounted by means of a bolt 16 in the two arms 10,11 of the bearing member 2, here having two side sections encasing the threaded rod (not shown here), said sections having a connecting web 41 at the bottom. In the lower section of the guide piece 18 there are located two slotted holes 19 directed downward, within which guide studs of a guide bolt connected to the threaded rod are slidably guided.

The arrangement of the guide nut 20 in the guide piece 18, and the way in which they work, can be derived from Fig.

which illustrates a view of the device in accordance with Fig. 2) as seen from above. The bearing member 2 is affixed underneath the seat-supporting member 7 and is 11 swivellably connected with the latter via a connection 6.

This, as shown here, can be a bolt, which is seated in the araLs 10,11 of the bearing member 2 and in the downward directed arms 42,43 of the seat-supporting member 7.

Affixed into the connection 6 designed as a bolt, in the design version as shown, there is also the anchoring element 37 for one end of the braking device, here the pneumatic spring 24. The anchoring of the pneumatic spring can, never-ieless, also be done on the bearing member 2.

and the braking device can be a mechanical spring or a mechanical springing device with protection against tension release, or the like. The pneumatic spring 24 extends toward the rear below and between the arms 10,11 of the beariiz member 2 and has two brackets 21 directed toward the guide piece 18. The guide piece 18 is rigidly connected to the cross bolt 16, which is rotatably seated in the arms 10,11 of the bearing member 2, and envelopes the brackets 21 of the pneumatic spring 24 with its two side sections. The guide bolt 20 is rotatably seated within two drill holes of the brackets 21, while two guide studs 23 project outward through the drill holes of the brackets 21 and, as described above, are slidably guided within the slotted holes of the guide piece 18. The guide nut 20 has in its centre, that is between the brackets r.j, 25 a tapped drill hole 22 directed downward, within which guided the threaded rod (not shown here). The threaded rod is seated, freely rotatable, with its upper end in the a* cross-bolt 16. If the threaded rod is then turned by means of an adjusting knob, the guide nut 20 is moved, under forcible guidance, toward the top or the bottom within the slotted holes 19 and, in so doing, takes with it the pneumatic spring 24 by means of the brackets 21, since the guide piece 18 is connected with the seat-supporting member 7 via the transposition mechanism 14 projecting through a 12 recess in the crosspiece 13 of the bearing membe- 2. The guide piece 18 for this purpose clasps around the connecting piece 17 with two flanges 34 directed toward the back, said connecting piece being rotatably seated by means of a pin or t-.o shaft ends within drill holes in the flanges 39,40. The connecting piece 17 is rotatably seated, in the same manner, at its other, upper, end between two downward directed flanges 33,34 of the seatsupporting member 7. In Fig. 3) a locking mechanism can, in addition, be recognized, said locking mechanism acting on the pneumatic spring 24 via a lever 46, a Bowden control cable, or the like, and b:ing used either to release it or to lock it into position.

The path of transposition can be derived from Fig. 2).

When the seat-supporting member 7 and the bearing member 2 are swivelled around the connection 6 in relation to one another, then the position of the slotted holes 19 is forcibly changed toward the front or toward the back, 20 depending on whether the connecting piece 17 shoves the guide piece 18 forward or pulls it backward, via the flanges 39, 40, by this movement. In practice the swivelling is accomplished by the actuation of the threaded rod, and therewith the guide piece 18, atc. By so doing, 25 the point of engagement on the braking device changes in each case, in which process a varying force is required for 'its actuation.

A different design version for the actuation of the device as per the invention which, as described above, occurs by means of turning the adjusting knob 25 and, with it, the threaded rod 15, is shown by Fig. 4) and Fig. Here the threaded rod 15 through the crossbolt 16, within which it turns freely, is extended beyond it and is rigidly affixed to a first gear wheel 26 which is located transversely to it. Between the side section of the guide piece 18 and an arm 10 of the bearing member 2 there is a bushing 31 rotatably seated on the crossbolt 16, which carries a second gear wheel 27 on the side of the bushing located further inward, affixed parallel to the arm 10, said gear wheel being in mesh with the first gear wheel 26. Farther outward on the bushing 31, next to the arm 10, a fourth gear wheel 29 is affixed, which is aligned the same way as is the the second gear wheel 27, and is rigidly connected with the latter via the bushing 31. Affixed farther below in the arm 10, parallel to it and rotatably seated within it, there is a third gear wheel 28, which meshes with the fourth gear wheel 29. This third gear wheel can be actuated by means of an adjusting screw, which is connected to it via a bolt extending outward through the arm 10. If the adjusting screw is actuated then all of the gear wheels 26,27,28 and 29 which mesh with one another are turned, and therefore also the threaded bolt 15 rigidly connected with the first gear wheel 26, which then, in the manner described above, brivrr its effect to bear on the means of adjustment, thi guide piece and the transposition mechanism, and therefore on the sp'.ing. It is, in addition, possible to simplify this arrangement even more by leaving out the bushing 31 and using only the second gear wheel 27, rotatably seated on the crossbolt 16 and meshing with the third gear wheel 28. The lateral S..actuation system using an adjusting screw and the gear wheels has the advantage that the adjusting screw will always be situated at the same place, whereas the adjusting knob affixed to the threaded rod, which is described in greater detail above, moves with the threaded rod and can take up varying positions.

Fig. 6 shows a bearing member 2' of a apecially advantageous design version of the invention. The connection between the bearing member 2' and the seatsupporting member 7 is here made by means of a bolt which is seated in a drill hole 49 at the front end of the bearing member in the arms 10',11' of that member, and in a drill hole at the front end of the seat-supporting member, in the arms of that member. The anchoring of the braking device is not done here, as shown in Fig. to this connecting bolt between the bearing member 2 and the seat-supporting member 7, but, instead, to a bolt affixed still farther forward on the bearing member said bolt being seated in drill holes 50 of the arms 10',11' of the bearing member It has been demonstrated that a specially favourable utilization of the available braking and transpositional forces can be achieved through this arrangement.

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Claims (16)

1. A device for adjusting the inclination of seat- type furniture, consisting of a U-shaped bearing member and having at its back end a seating recess for the support column of a cruciform base and at its front end a swivellable connection with the front end of a seat- supporting member, which extends backward, at least in part, over the bearing member, in which device the bearing member and the seat-supporting member are swivellable around the swivellable connection, working against the force of a braking device, and in which device means of adjustment are provided for changing the positions of the bearing member and the seat-supporting member, characterised in that the braking device is connected at its front end with the front end of the bearing member, and at its back end with the means of adjustment, in that the braking device is longitudinally variable, :in that the means of adjustment is a threaded 20 rod, directed downward from the bearing member, which is freely rotatable at its upper end where it is seated in a crossbolt which is rotatably seated in the arms of the bearing member, in that the threaded rod does not have inherent 25 non-reversibility in that a transposition mechanism is a rotatably seated connecting piece attached to the under side of the seat-supporting member and a guide piece swivellably connected with it, both being located between the means of adjustment and the seat-supporting member, in which the guide piece has a slotted hole in its other, lower, section, in which the means of adjustment is slidably seated, said transposition mechanism projecting through a recess in the crosspiece of the bearing member, and bringing about a shifting of the point of engagement on the braking device, and in that the swivelling range between the bearing member and the seat-supporting member, and thus the shifting of the point of engagement on the braking device, can be regulated by means of the means of adjustment.

2. A device for adjusting the inclination of seat- type furniture as per Claim 1, characterised in that the guide piece extends further downward beyond the crossbolt, in that the guide piece has at least one slotted hole directed downward in this lower section, in that the braking device is connected with the means of adjustment via a guide nut, in that the guide nut is rotatably seated in at .i least one bracket of the braking device directed toward the means of adjustment, in that the guide nut has a tapped drill hole for the threaded rod of the means of adjustment, 15 and in that the guide nut is seated with at least one guide stud in the slotted hole of the guide piece. S

3. A device for adjusting the inclination of seat- type furniture as per Claim 1, characterised in that the braking device is a spring.

4. A device for adjusting the inclination of seat- type furniture as per Claim 3, characterised in that the spring can be locked into any possible position between its shortest and its longest extension, and in that the locking effect is capable of being actuated by means of an adjusting lever projecting out laterally through or under an arm of the bearing member. A device for adjusting the inclination of seat- type furniture as per Claim 4, characterised in that the spring is a pneumatic spring.

6. A device for adjusting the inclination of seat- type furniture as per Claim 3, characterised in that the spring has a curvilinear characteristic shape. S S. 7. A device for adjusting the inclination of seat- type furniture as per Claim 1, characterised in that the bearing member and the seat-supporting member can be locked into position relative to one another by means of the means of adjustment in its start and in its end positions. a

8. A device for adjusting the inclination of seat- type furniture as per Claim 1, characterised in that the braking device or the guide piece are capable of being locked into position by means of locking mechanisms.

9. A device for adjusting the inclination of seat- type furniture as per Claim 3, characterised in that the threaded rod has, at its lower end, an adjusting knob which is rigidly attached to the end of the rod. A device for adjusting the inclination of seat- type furniture as per Claim 3, characterised in that the threaded rod projects upward through the crossbolt and is rigidly connected there with a first gear wheel that is located transversely to it, in that the first gear wheel meshes with a second gear wheel, which is affixed next to the guide piece and offset at 900 to the first gear wheel, in that the second gear wheel is rotatably seated on the crossbolt and is affixed between one of the arms of the bearing member and the guide piece, in that the second gear wheel meshes with a third gear wheel which is rotatably seated further down in the 15 arm and aligned the same way, and in that this third gear wheel is connected with a bolt which projects outward through the arm and is provided with an adjusting wheel.

11. A device for adjusting the inclination of seat- type furniture as per Claim 3, characterised in that the threaded rod projects upward through the crossbolt and is rigidly fastened thereto a first gear wheel which is located transversely to it, in that the first gear wheel meshes with a second gear wheel which is affixed next to the guide piece and offset at 90° to the first gear wheel, in that the second gear wheel is fastened to a bushing which is rotatably seated on the crossbolt and affixed between an arm of the bearing member and the guide piece, in that a fourth gear wheel is fastened onto the bushing next to the arm of the bearing member, in that the fourth wheel meshes with a third gear wheel which is rotatably seated further down in the arm and aligned the same way, and in that this third gear wheel is connected with a bolt which projects downward through the arm and is provided with an adjusting wheel.

12. A device for adjusting the inclination of seat- type furniture as per Claim characterised in that the first gear wheel and the second gear wheel are bevel-gear wheels.

13. A device for adjusting the inclination of seat- :type furniture as per Claim 10 or 11, :characterised in that at least one of the gear wheels has, in each case, only one toothed segment within the required actuation range.

14. A device for adjusting the inclination of seat- type furniture as per Claim 13, characterised in that at least one of the gear wheels is restricted in its travel, by a catch for example. 7: A device for adjusting the inclination of seat- type furniture as per Claims 10 to 12, characterised in that a click-stop device is affixed between the third gear wheel and the arm through vrhich the bolt connected with the adjusting wheel projects, said click-stop device being capable of actuation by means of the adjusting wheel.

16. A device for adjusting the inclination of seat- type furniture as per Claim characterised in that the click-stop device consists of at least one lug and a number of click-stop holes, in which case either the lug is affixed to the third gear wheel and the click- stop holes are located on the arm, or else the lug is affixed to the arm and the click-stop holes are located on the third gear wheel.

17. A device for adjusting the inclination of seat- type furniture as per Claim 16, characterised in that the click-stop device consists of a clamping collet that can be brought into engagement with the third gear wheel by means of the adjusting wheel.

18. A device for adjusting the inclination of seat- type furniture as per Claim 1, characterised in that at least one spring is affixed between the o bearing member and the seat-supporting member.

19. A device for adjusting the inclination of seat- type furniture as per Claim 18, characterised in that the at least one spring is so designed that it supports the weight of the seat-supporting member plus its upholstery and, where applicable, any additional parts associated with it. A device for adjusting the inclination of seat- type furniture as per Claim 18, characterised in that the at least one spring is capable of being attached at various points between the bearing member and the seat-supporting member.

21. A device for adjusting the inclination of seat- type furniture as per Claim 1, characterised in that the connection of the bearing member with the seat-supporting member is made at their front ends, but so arranged that it is behind the anchoring point of the *I braking device oc. the bearing member. DATED this 16th day of September, 1993. SIFA SITZFABRIK GmbH By Its Patent Attorneys GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia *f N **oo oo*o o