GB1598515A

GB1598515A - Telescopic swivelling spring supporting device particularly for the seat of a swivel chair and spring unit for use in such a supporting device

Info

Publication number: GB1598515A
Application number: GB8810/78A
Authority: GB
Original assignee: GISPEN BV
Current assignee: GISPEN BV
Priority date: 1977-02-14
Filing date: 1978-03-06
Publication date: 1981-09-23
Also published as: NL177074C; BE864805A; NL7701544A; DE2809850A1; DE2809850C2; NL177074B; FR2419052A1; FR2419052B1

Description

(54) A TELESCOPIC SWIVELLING SPRING SUPPORTING DEVICE, PARTICULARLY FOR THE SEAT OF A SWIVEL CHAIR AND SPRING UNIT FOR USE IN SUCH A SUPPORTING DEVICE (71) We, GISPEN B.V., a Private Limited Liability Company organised under the laws of the Netherlands, of Stationssingel 25, Culemborg, The Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: The invention relates to a telescopic swivelling spring supporting device, particularly for the seat of a swivel chair, said device comprising a tubular standard, an inner tube mounted therein for up and down movement and adapted to be coupled by means of a radially movable projection at various levels to a member which rests by way of a precompressed spring and a thrust bearing on the bottom of the standard and has a vertical row of holes, into one of which said projection is, in use, inserted. In the known telescopic spring supporting devices which, for instance, are used in swivel chairs the device is composed of a large number of parts, whereas, when the spring has to be mounted under pre-compression, this can be realized with difficulty only. In order to obtain a favourable supporting device it is then often necessary to use two springs of different rigidities.The invention has the object to provide such a supporting device which consists of a few parts only and can be mounted in a simple way.

In accordance with one aspect of the invention, the member with the vertical row of holes extends within the inner tube which contains in its upper portion a lever extending substantially within the inner tube and with its lower end also within the member with holes, the lever being pivoted about a horizontal pin which is mounted in the inner tube or in a part attached thereto and the projection is supported by the lower end of the lever and is forced towards said holes by a spring acting on the lever, and the upper end of the lever is provided, or adapted to co-operate, with an operating handle.

In this construction of the supporting device the number of component parts is reduced to a minimum. The load is transmitted through the pivot of the swingable lever and, by means of the projection, through the lever itself to the member provided with the vertical row of holes which is supported by way of the pre-compressed spring by the standard.

Furthermore according to a preferred feature of the invention the member with the row of holes is provided at the lower end with a rod which is axially movable in respect of said member and round which a compression spring is mounted which lies under precompression at one end against the lower end of said member or against a part attached thereto and at the other end against a spring washer secured to the rod. In this embodiment the spring can be mounted on the rod and fastened by means of the spring washer before the d.evice is mounted. Therefore it is easy to use tools to mount the springs.

According to another preferred feature of the invention it is also possible to allow the compression spring to lie against the said member by way of a spring washer which is attached to the lower end of the member and to allow the rod to be forced, by the spring compression, with a collar at its upper surface of the spring washer attached to the member.

In that case one and the same part is used to lock the rod in respect of the member with holes and to provide a supporting surface for the compression spring.

According to another preferred feature of the invention one of the parts formed by the member with a row of holes and by the rod may have a slot and the other one of said parts may be provided with a pin adapted to slide in said slot, the arrangement being such as to allow the pin to be forced against one end of the slot by the spring compression. The slot may be formed either in the rod or in the member with the row of holes. The length of the slot defines the free stroke of the rod in respect of the member having the row of holes.

In accordance with another preferred feature of the invention a thrust bearing, for which the lower side of the spring washer forms a bearing race and the other bearing race of which rests on a plate secured to the lower end of the tubular standard, may be provided on the free lower end of the rod and this free lower end of the rod may extend through an opening of the plate and be locked against displacement in respect of said plate by a locking member. In this embodiment the rod also carries the bearing and the spring washer serves both to support the spring and to form a race of the bearing.

According to another preferred feature of the invention the member with the holes may be formed by a channel beam, of which the web has the row of holes, and the lever may be provided with a projection lying between the flanges of the channel beam, whereas the flanges of the channel beam may be bent inwards at the upper ends, so as to form a stop for the upward displacement of the projection. Such a member can be made in a simple way and the limitation of the upward stroke of the projection is easily achieved. Thereby it is prevented that the tube with the lever is pulled upwards out of the device.

According to another preferred feature of the invention the pivot of the lever may be mounted in a clamping body secured to the upper end of the inner tube and carrying the part to be supported and the lever may be provided with a horizontally extending extension piece with handle. This construction makes the operation of the lever for adjusting the supporting device vertically very simple.

In accordance with another preferred feature of the invention the lever may furthermore be provided with a stop which is held by the upper side of the member with holes, when the projection has passed, during its downward movement the lowermost hole. Thereby also in downward direction an effective limitation of the stroke in the required place is obtained.

According to another preferred feature of the invention the lever may be supported at its upper end by a horizontal pivot mounted in the clamping body and the upper end portion of the lever may have a bevelled cam surface which is adapted to co-operate with the free end of a horizontally extending pivoted lever carrying a handle at the other end. This embodiment provides a separate lever for the operation of the projection. A stop to limit the downward stroke of the lever is not necessary as the end of the lever hits the upper side of the member having the row of holes.

The invention also relates to a longitudinally adjustable spring unit for use in a supporting device of the above described kind.

According to this aspect of the invention this unit comprises a tube, a member having a vertical row of holes and extending within said tube, a lever extending substantially within the upper portion of the tube and with its lower end within the member with holes and pivoted about the horizontal pin mounted in the tube or in a part attached thereto, a projection carried by the lower end of the lever and forced towards the holes by a spring acting on the lever and a rod mounted for relative movement co-axially with the lower end of the member which has the row of holes and carrying round it a compression spring which is forced by pre-compression with one end against the lower end of the member or against a part secured thereto and with the other end against a spring washer attached to the rod, the free end portion of the rod providing beneath the lower spring washer a support for a thrust bearing and a locking plate. Such a spring unit may have exactly the same dimensions as the so-called gas-springs, so that they can be universally used, e.g. in swivel chairs.

In an effective embodiment the spring washer provided at the end of the rod may form with its lower side a bearing race for a thrust bearing mounted in the rod.

The invention will be further elucidated in the following description of an embodiment illustrated in the drawings. In the drawings: Figure 1 is partly a sectional view and partly an elevational view of a chair provided with an adjustable device according to the invention, when in its highest condition, Figure 2 is a sectional view and an elevational view corresponding to those shown in Figure 1, when the chair is in its lowest position.

Figure 3 is a sectional view taken on line III-III in Figure 2.

Figure 4 is a sectional view corresponding to that shown in Figure 1 of an other embodiment of the invention.

In Figures 1, 2 and 3 a chair is shown which has a seat 1 of which only the frame is illustrated. Attached to the seat 1 a clamping piece 2 which is secured to the upper end of a tube 4 by means of bolts 3. This tube 4 extends within a tube 5 of the standard of the chair.

The tube 5 forms part of a base frame 6 which is provided with castor. wheels 7. The tube 4 is mounted for sliding in the tube 5 and it is guided by an insert piece 8 which engages the tube 5 with a ring 9 and a tubular portion 10 of which forms a bearing for the tube 4. Provided within the tube 4 is a lever pivoted about a horizontal pivot 11. The lever 12 has at its upper end a bevelled cam surface 13 which is adapted to co-operate with the free end of a lever 14 which is pivoted about a pivot 15 provided in the clamping piece 2. The lever 14 has a handle 16. When the handle 16 is moved upwards, whereby the lever comes into the position 14', the lever 12 is swung about the pivot 11.

The lever 12 has at its lower end a projec tion 17 which is brought into position 17', when the handle 16 is moved in the described way. Provided within the tube 4 is a channel shaped member 18 which has a vertical row of holes 19. In the position shown in Figure 1 the projection 17 is inserted into the uppermost hole 19. The channel-shaped member has flanges 20, of which the upper end portions are bent over to form an edge 21 limiting the upward movement of the projection 17. The channel-shaped member 18 has at the lower end a plate 22 which is rigidly connected to the member 18. This plate 22 has a central opening, through which a rod 23 extends which engages with a collar 24 behind the edge of the opening of plate 22.Provided on the rod 23 is a compression spring 25 which at one end lies against the plate 22 operating as a spring washer and at the other end is blocked by an annular plate 26. This plate 26 is fixed to the rod 23.

The plate 26 serves as upper bearing race for a thrust bearing 27, of which the lower bearing race 28 lies against a bottom plate 29 mounted in the tube 5. The bottom plate 29 has a central opening through which the end portion of the rod 23 extends. Mounted on the end portion 30 of the rod 23 is a locking ring 31 which is held in place by a retaining member 32.

The lever 12 is subjected to the action of a spring 33. The projection is always in one of the holes 19, when the lever 14 is not operated.

The force exerted on the seat of the chair is transmitted to the lever 12 through the pivot 11 and from there through the projection 17 to the channel-shaped member 18. Owing to the compression spring 25 which supports the member 18, a spring action is obtained when the chair is used. If the lever of the chair must be changed the lever 14 is operated by means of the handle 16. Then the lever 12 is swung into the position 12' by the action of the end of lever 14 on the cam surface 13, whereby the projection 17 is brought into position 17' and is pulled out of the opening 19. Thereupon the seat 1 can be moved downwards. When thereafter the handle 16 is released, the projection 17 engages an opening 19 on a lower level, so that the chair is held in the new position but keeps its spring action.

Figure 2 shows the chair in its lowermost position. If the lever 14 is operated a too long time, so that the projection 17 will have passed all openings 19, the stop 40 formed on the lever 12 will be held by the upper edge of the channel-shaped member 18 and will thereby prevent that the clamping piece 2 comes into contact with the insert piece 8.

An important advantage of the described construction is that the spring device can be provided as a unit. Such a unit then consists of the inner tube 4, the lever 12, the channelshaped member 18, the rod 23 and the spring 25. The spring 25 is compressed in advance and is held in its pre-compressed state by the plate 26. It is possible to mount the entire spring device as a unit into a standard for a chair and thereafter to attach the seat thereto. The outer dimensions may then be made to the same as those of the usual so-called gas springs. These gas springs are also provided as units and used by the manufacturers in furniture. The spring units according to the invention may also be provided as standard units, so that they can be used by various manufacturers.The described spring unit has the advantage of a very simple construction which does not require special tools for its assembly into a piece of furniture.

Figure 4 shows an embodiment which substantially corresponds with that illustrated in Figure 1-3. Therein the lever 12 is replaced by a lever 34 which is so extended as to form a part 35 which takes the place of the lever 14.

The lever 34 is pivoted about the pivot 36 which is mounted in the clamping piece 2.

The lever 34 is forced by a leaf spring 37 into a position, in which the projection 38 corresponding to the projection 17 engages one of the holes 19 of the channel-shaped member 18.

The lever 34 has a stop member 39, which contacts the upper end of the channel-shaped member 18, when the chair reaches its lowermost position, in order to prevent that the clamping piece 2 comes into touch with the upper side of the insert piece 8.

In this case the spring 25 is forced instead of against a spring washer 22 directly against the lower side of the member 18 provided with the row of holes. The member with holes has a slot 41. A pin 42 extends through the rod 23 and is adapted to slide in the slot 41 with its end portions. In the shown condition the pin 42 is forced against the end of the slot 41. The length of the slot 41 defines the free stroke of the rod 23 in respect of the member 18 having the row of holes. As to the rest the device shown in Figure 4 is the same as that illustrated in Figures 1-3.

WHAT WE CLAIM IS: 1. A telescopic swivelling spring supporting device, particularly for the seat of a swivel chair, said device comprising a tubular standard, an inner tube mounted therein for up and down movement and adapted to be coupled by means of a radially movable projection at various levels to a member which rests by way of a precompressed spring and a thrust bearing on the bottom of the standard and has a vertical row of holes, into one of which said projection is, in use, inserted, characterized in that the member with the vertical row of holes extends within the inner tube which contains in its upper portion a lever extending substantially within the inner tube and with its lower end also within the member with holes, the lever being pivoted about a horizontal pin which is mounted in the inner tube or in a part attached thereto, characterized in that the projection is supported by the lower end of the lever and is forced towards said holes by a spring acting on the lever, and the upper end of the lever is provided or adapted to co-operate with an operating handle.

2. A supporting device according to Claim 1, characterized in that the member with the row of holes is provided at the lower end with a rod which is axially movable in respect of said member and round which the compression spring is mounted which lies under pre-compression at one end against the lower end of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. end a plate 22 which is rigidly connected to the member 18. This plate 22 has a central opening, through which a rod 23 extends which engages with a collar 24 behind the edge of the opening of plate 22. Provided on the rod 23 is a compression spring 25 which at one end lies against the plate 22 operating as a spring washer and at the other end is blocked by an annular plate 26. This plate 26 is fixed to the rod 23. The plate 26 serves as upper bearing race for a thrust bearing 27, of which the lower bearing race 28 lies against a bottom plate 29 mounted in the tube 5. The bottom plate 29 has a central opening through which the end portion of the rod 23 extends. Mounted on the end portion 30 of the rod 23 is a locking ring 31 which is held in place by a retaining member 32. The lever 12 is subjected to the action of a spring 33. The projection is always in one of the holes 19, when the lever 14 is not operated. The force exerted on the seat of the chair is transmitted to the lever 12 through the pivot 11 and from there through the projection 17 to the channel-shaped member 18. Owing to the compression spring 25 which supports the member 18, a spring action is obtained when the chair is used. If the lever of the chair must be changed the lever 14 is operated by means of the handle 16. Then the lever 12 is swung into the position 12' by the action of the end of lever 14 on the cam surface 13, whereby the projection 17 is brought into position 17' and is pulled out of the opening 19. Thereupon the seat 1 can be moved downwards. When thereafter the handle 16 is released, the projection 17 engages an opening 19 on a lower level, so that the chair is held in the new position but keeps its spring action. Figure 2 shows the chair in its lowermost position. If the lever 14 is operated a too long time, so that the projection 17 will have passed all openings 19, the stop 40 formed on the lever 12 will be held by the upper edge of the channel-shaped member 18 and will thereby prevent that the clamping piece 2 comes into contact with the insert piece 8. An important advantage of the described construction is that the spring device can be provided as a unit. Such a unit then consists of the inner tube 4, the lever 12, the channelshaped member 18, the rod 23 and the spring 25. The spring 25 is compressed in advance and is held in its pre-compressed state by the plate 26. It is possible to mount the entire spring device as a unit into a standard for a chair and thereafter to attach the seat thereto. The outer dimensions may then be made to the same as those of the usual so-called gas springs. These gas springs are also provided as units and used by the manufacturers in furniture. The spring units according to the invention may also be provided as standard units, so that they can be used by various manufacturers.The described spring unit has the advantage of a very simple construction which does not require special tools for its assembly into a piece of furniture. Figure 4 shows an embodiment which substantially corresponds with that illustrated in Figure 1-3. Therein the lever 12 is replaced by a lever 34 which is so extended as to form a part 35 which takes the place of the lever 14. The lever 34 is pivoted about the pivot 36 which is mounted in the clamping piece 2. The lever 34 is forced by a leaf spring 37 into a position, in which the projection 38 corresponding to the projection 17 engages one of the holes 19 of the channel-shaped member 18. The lever 34 has a stop member 39, which contacts the upper end of the channel-shaped member 18, when the chair reaches its lowermost position, in order to prevent that the clamping piece 2 comes into touch with the upper side of the insert piece 8. In this case the spring 25 is forced instead of against a spring washer 22 directly against the lower side of the member 18 provided with the row of holes. The member with holes has a slot 41. A pin 42 extends through the rod 23 and is adapted to slide in the slot 41 with its end portions. In the shown condition the pin 42 is forced against the end of the slot 41. The length of the slot 41 defines the free stroke of the rod 23 in respect of the member 18 having the row of holes. As to the rest the device shown in Figure 4 is the same as that illustrated in Figures 1-3. WHAT WE CLAIM IS:

1. A telescopic swivelling spring supporting device, particularly for the seat of a swivel chair, said device comprising a tubular standard, an inner tube mounted therein for up and down movement and adapted to be coupled by means of a radially movable projection at various levels to a member which rests by way of a precompressed spring and a thrust bearing on the bottom of the standard and has a vertical row of holes, into one of which said projection is, in use, inserted, characterized in that the member with the vertical row of holes extends within the inner tube which contains in its upper portion a lever extending substantially within the inner tube and with its lower end also within the member with holes, the lever being pivoted about a horizontal pin which is mounted in the inner tube or in a part attached thereto, characterized in that the projection is supported by the lower end of the lever and is forced towards said holes by a spring acting on the lever, and the upper end of the lever is provided or adapted to co-operate with an operating handle.

said member or against a part attached thereto and at the other end against a spring washer secured to the rod.

3. A supporting device according to Claim 2, characterized in that the compression spring lies against the said member by way of a spring washer which is attached- to the lower end of the member and the rod is forced, by the spring compression, with a collar at its upper end against the upper surface of the spring washer attached to the member.

4. A supporting device according to Claim 2, characterized in that one of the parts formed by the member with a row of holes and by the rod has a slot and the other one of said parts is provided with a pin adapted to slide in said slot, the arrangement being such as to allow the pin to be forced against one end of the slot by the spring compression.

5. A supporting device according to any one of the foregoing claims, characterized in that provided on the free lower end of the rod is a thrust bearing, for which the lower side of the spring washer forms a bearing race and the other bearing race of which rests on a plate secured to the lower end of the tubular standard, and the free end of the rod extends through an opening of the plate and is locked against displacement in respect of said plate by a locking member.

6. A supporting device according to any one of the foregoing claims, characterized in that the member with the holes is formed by a channel beam, of which the web has the row of holes, and the lever is provided with a projection lying between the flanges of the channel beam, whereas the flanges of the channel beam are bent inwards at the upper ends, so as to form a stop for the upward displace- ment of the projection.

7. A supporting device according to any one of the foregoing claims, characterized in that the pivot of the lever is mounted in a clamping body secured to the upper end of the inner tube and carrying the part to be supported and the lever is provided with a horizontally extending extension piece with handle.

8. A supporting device according to any one of the foregoing claims, characterized in that the lever is provided with a stop which is held by the upper side of the member with holes, when the projection has passed, during its downward movement, the lowermost hole.

9. A supporting device according to any one of Claims 1-6, characterized in that the lever is supported at its upper end by a horizontal pivot mounted in the clamping body and the upper end portion of the lever has a bevelled cam surface which is adapted to co-operate with the free end of a horizontally extending pivoted lever which carries a handle at the other end.

10. A longitudinally adjustable spring unit for use in a supporting device according to any one of the foregoing claims, characterized in that the unit comprises a tube, a member having a vertical row of holes and extending within said tube, a lever extending substantially within the upper portion of the tube and with its lower end within the member with holes and pivoted about a horizontal pin mounted in the tube or in a part attached thereto, a projection carried by the lower end of the lever and forced towards the holes by a spring acting on the lever and a rod mounted for relative movement co-axially with the lower end of the member which has the row of holes and carrying round it a -compression spring which is forced by pre-compression with one end against the lower end of the member or against a part secured thereto and with the other end against a spring washer attached to the rod, the free end portion of the rod providing beneath the lower spring washer a support for a thrust bearing and a locking plate.

11. A unit according to Claim 10, characterized in that the spring washer provided at the end of the rod forms with its lower side a bearing race for a thrust bearing mounted on the rod.

12. A supporting device according to any one of the claims 1-9 substantially as described with reference to the accompanying drawings.

13. A longitudinally adjustable spring unit according to Claim 10 or 11 substantially as described with reference to the accompanying drawings.