NL2035885B1

NL2035885B1 - An office chair with a weight adjustment mechanism

Info

Publication number: NL2035885B1
Application number: NL2035885A
Authority: NL
Inventors: Van Seggelen Stefan
Original assignee: Koninklijke Ahrend B V
Priority date: 2023-09-26
Filing date: 2023-09-26
Publication date: 2025-04-01
Also published as: WO2025071396A1

Abstract

An office chair (1) comprising a seat (2) and a back rest (3), as well as a weight adjustment mechanism (4) with a spring (5) for adjusting the chair (1) to a particular weight of a user, which spring (5) engages a sliding block (6) that is movable along the spring (5) for setting the chair to said weight, which sliding block (6) is drivable by a cable (7) operated. pinion (8) that forms part of a rack and pinion 10 systemJ which. system. further* comprises a rack (9) which is connected to the sliding block (6), wherein between the cable (7) operated pinion (8) and the cable (7) a transitory mechanism (10) is provided for transferring an adjustment of the cable (7) to an adjustment of at least one of the 15 transitory mechanism (10) and the pinion (8).

Description

An office chair with a weight adjustment mechanism

The invention relates to an office chair comprising a seat and a backrest, as well as a weight adjustment mechanism with a spring for adjusting the chair to a particular weight of a user.

EP 1 570 767 discloses such a chair comprising adjustment means for individual adjustment of the resilience of the seat and/or the backrest of the chair in dependence on the user's weight, said weight regulator comprising primary adjustment means for a coarse adjustment and secondary adjustment means for a fine adjustment of the resilience of the seat or of the backrest by tilting/movement, said adjustment means operating between a lower bearing point and a base frame, said adjustment means being unloaded at the moment of adjustment.

It is an object of the invention to make inputting a setpoint for the weight adjustment mechanism of the chair possible without the chair always being required to be in a neutral unloaded position.

According to the invention an office chair is proposed having the features of one or more of the appended claims.

In a first aspect of the invention the spring of the chair engages a sliding block and the sliding block is movable along the spring for setting the chair to said weight, which sliding block is drivable by a cable operated pinion that forms part of a rack and pinion system, which system comprises a rack which is connected to the sliding block, and wherein between the cable operated pinion and the cable a transitory mechanism is provided for transferring an adjustment of the cable to an adjustment of at least one of the transitory mechanism and the pinion.

The office chair of the invention provides that when the office chair is loaded with the weight of the user, an adjustment of the cable translates into an adjustment of the transitory mechanism in anticipation of a later adjustment of the pinion that controls the position of the sliding block.

The adjustment of the pinion which is not yet possible because of the chair being loaded with the weight of the user, is thus stored into a temporary adjustment of the transitory mechanism. Accordingly when the office chair is unloaded the previous adjustment of the cable which is stored or memorized in the transitory mechanism, can then translate into an adjustment of the pinion with a corresponding motion of the sliding block along the spring for setting the weight for the chair.

It is preferred that the transitory mechanism comprises a rotatable ring which is linked to the cable, and which rotatable ring is drivingly connected to the pinion by interposition of at least one spring that is connected to the rotatable ring, wherein the spring connects to the pinion for absorbing a rotation of the ring with respect to the pinion when the chair is loaded, and that said spring causes the pinion to follow the rotation of the ring when the chair is unloaded.

Suitably the cable is a Bowden cable.

In a preferred embodiment the rack and pinion system comprises one pinion and two racks, wherein between one of the racks and the pinion a spur gear is provided to ensure symmetrical operation of both racks.

The invention will hereinafter be further elucidated with reference to the drawing of an exemplary embodiment of the invention that is not limiting as to the appended claims.

In the drawing: -figures 1A and 1B show an office chair of the invention from the front and from the side; -figure 1C shows detail B of figure 1B; -figure 2 shows the weight adjustment mechanism of the office chair of the invention in an exploded view; -figure 3A provides a top view of the weight adjustment mechanism; figure 3B provides a cross-sectional view along line

A-A in figure 33; -figures 4A, 4B, 4c and 4D show respectively a bottom view and a side view at the weight adjustment mechanism, and a cross-sectional view according to the line A-A in figure 4A; -figures 5SA-F show different input positions of the cable driving the weight adjustment mechanism in different stages of operation of the chair.

Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

With reference to figures 1A and 1B an office chair 1 of the invention is shown, comprising a seat 2 and a backrest 3. The chair 1 further comprises a weight adjustment mechanism 4 with a spring 5 for adjusting the chair to a particular weight of a user. This can be best seen in figure 1C, showing detail B of figure 1B. The spring 5 engages a sliding block 6 which is movable along the spring 5 for setting said weight.

Figure 2 provides an exploded view of the weight adjustment mechanism 4 and makes clear that the sliding block 6 is drivable by a cable 7 operated pinion 8 that forms part of a rack and pinion system, details of which are shown in figure 4A-D. See also figure 3A. The cable 7 is preferably a Bowden cable.

Figure 2, figure 3A and figures 4A-D show that the rack and pinion system comprises a (double) rack 9 which is connected to the sliding block 6, and that between the cable 7 operated pinion 8 and the cable 7 a transitory mechanism 10 is provided for transferring an adjustment of the cable 7 to an adjustment of at least one of the transitory mechanism 10 and the pinion 8. This arrangement provides that when the office chair 1 is loaded with the weight of the user and the pinion 8 is Dlocked from moving because of the frictional contact between the sliding block 6 and the spring 5, an adjustment of the cable 7 translates only into an adjustment of the transitory mechanism 10. Likewise when the office chair 1 is unloaded enabling again movement of the pinion 8 because then the frictional contact between the sliding block 6 and the spring 5 is removed, an adjustment of the cable 7 then translates into an adjustment of the pinion 8.

In the shown preferred embodiment the transitory mechanism 10 comprises a rotatable ring 10’ which is linked to the cable 7. This rotatable ring 10’ is drivingly connected to the pinion 8 by interposition of a spring 11 that is connected to the rotatable ring 10’. The spring 11 connects at reference 8’ (see fig. 4D) to the pinion 8 for absorbing clockwise rotation of the ring 10’ with respect to the pinion 8 when the chair 1 is loaded. Said spring 11 causes the pinion 8 to follow the clockwise rotation of the ring 10’ when the chair 1 is unloaded. Likewise the spring 11, which connects at reference 8’ to the pinion 8, is arranged for absorbing counterclockwise rotation of the ring 10’ with respect to the pinion 8 when the chair 1 is loaded. The spring 11 will cause the pinion 8 to follow the counterclockwise rotation of the ring 10’ when the chair 1 is unloaded. Figure 3B shows the position of the spring llbeing placed between the rotatable ring 10° and the pinion 8.

Figure 2, figure 3A and figures 4A-D further show that the rack and pinion system comprises one pinion 8 and two racks 9, wherein between one of the racks 9 and the pinion 8 a spur gear 13 is provided to ensure symmetrical operation of both racks 9.

The invention enables that a setting knob that connects to the Bowden cable 7 can be operated also when the chair 1 of the invention is loaded with the weight of user. In that situation the transitory mechanism 10 as employed in the invention absorbs the displacement of the Bowden cable 7, without such displacement immediately being transferred to the pinion 8 that drives the racks 9 of the rack and pinion system. Consequently the position of the sliding block 6 acting on the spring 5 of the chair is at that time unaffected. The change of position of the sliding block 6 acting on the spring 5 in accordance with the adjustment of the Bowden cable 7 only comes into effect after the chair of the invention is released from the weight of the user. The effect of the invention is clearly recognizable with a view at the comparative figures HA - F.

In the series of figures 5A - F the position of the

Bowden cable 7 is shown as reflected by the position of the rotatable ring 10’ and the corresponding rotation of the spring 11 which reflects whether the chair is loaded or unloaded by the weight of a user. Correspondingly figures bA -

F show the output positions of the rack and pinion system as recognizable by the position of the sliding block 6.

For comparative purposes figure 5A shows a starting middle position of the sliding block 6, wherein the spring 11 is in a neutral position and the chair 1 is unloaded.

In the next figure 5B the chair 1 is still unloaded, and the Bowden cable 7 has been used to rotate the rotatable ring 10’ clockwise so as drive the pinion 8 to bring the sliding block 6 to position ‘light’.

In figure 5C the chair is loaded, and the adjustment of the Bowden cable 7 has brought the rotatable ring 10’ to a 5 position wherein spring 11 has absorbed the motion that cannot be transferred to the pinion 8 as long as the chair is loaded.

The setting of the sliding block 6 is maintained at the position ‘light’.

In the next figure 5D the position of the rotatable ring 10’ is maintained, however the load has been removed from the chair, and consequently the spring 11 has relaxed to bring the pinion 8 in the position that corresponds to the position of the rotatable ring 10’ which corresponds to the setting of the sliding block 6 ‘heavy’. Figure 5E shows the compression of the further spring 11 whilst the sliding block is in the position ‘mid’ and the chair is loaded, which prevents that the pinion 8 follows the rotation of the rotatable ring 107.

As a consequence the spring 11 is compressed to absorb the difference in rotation of the rotatable ring 10" and the pinion 8.

Finally, Figure 5F shows a ‘mid’ position again for block 6 and a spring 11 going back to its initial position.

Embodiments of the present invention can include every combination of features that are disclosed herein independently from each other. Although the invention has been discussed in the foregoing with reference to an exemplary embodiment of the invention, the invention is not restricted to this particular embodiment which can be varied in many ways without departing from the invention. The discussed exemplary embodiment shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary the embodiment is merely intended to explain the wording of the appended claims without intent to limit the claims to this exemplary embodiment. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using this exemplary embodiment.

Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference. Unless specifically stated as being “essential” above, none of the various components or the interrelationship thereof are essential to the operation of the invention. Rather, desirable results can be achieved by substituting various components and/or reconfiguration of their relationships with one another.

Aspects of the invention are itemized in the following section. 1. An office chair (1) comprising a seat (2) and a back rest (3), as well as a weight adjustment mechanism (4) with a spring (5) for adjusting the chair (1) to a particular weight of a user, characterized in that the spring (5) engages a sliding block (©) and that the sliding block (6) is movable along the spring (5) for setting the chair to said weight, which sliding block (6) is drivable by a cable (7) operated pinion (8) that forms part of a rack and pinion system, which system comprises a rack (9) which is connected to the sliding block (6), and that between the cable (7) operated pinion (8) and the cable (7) a transitory mechanism (10) is provided for transferring an adjustment of the cable (7) to an adjustment of at least one of the transitory mechanism (10) and the pinion (8). 2. The office chair of claim 1, characterized in that when the office chair (1) is loaded with the weight of the user an adjustment of the cable (7) translates into an adjustment of the transitory mechanism (10). 3. The office chair of claim 1 or 2, characterized in that when the office chair (1) is unloaded an adjustment of the cable (7) translates into an adjustment of the pinion (8). 4. The office chair of any one of claims 1 - 3, characterized in that the transitory mechanism (10) comprises a rotatable ring (10’) which is linked to the cable (7), and which rotatable ring (10') is drivingly connected to the pinion (8) by interposition of at least one spring (11) that is connected to the rotatable ring (107), wherein said spring connects to the pinion (8) for absorbing rotation of the ring

(107) with respect to the pinion (8) when the chair (1) is loaded, and wherein said spring (11) causes the pinion (8) to follow the rotation of the ring (10’) when the chair (1) is unloaded. 5. The office chair of any one of claims 1 - 4, characterized in that the cable (7) is a Bowden cable.

6. The office chair of any one of claims 1 - 5, characterized in that the rack and pinion system comprises one pinion (8) and two racks (9), wherein between one of the racks

{9) and the pinion (8) a spur gear (13) 1s provided to ensure symmetrical operation of both racks (9).

Claims

CONCLUSIONS

1. An office chair (1) comprising a seat (2) and a backrest (3), as well as a weight adjustment mechanism (4) with a spring (5) for adjusting the chair (1) to a certain weight of a user, characterised in that the spring (5) engages a slide block (6) and that the slide block (6) is movable along the spring (5) for adjusting the chair to said weight, which slide block (6) is drivable by a cable (7) operated pinion (8) which forms part of a rack and pinion system, which system comprises a rack and pinion (9) connected to the slide block (6), and that a transmission mechanism (10) is provided between the cable (7) operated pinion (8) and the cable (7) for transmitting an adjustment of the cable (7) to an adjustment of at least one of the transmission mechanism (10) and the pinion (8).

2. Office chair according to claim 1, characterised in that when the office chair (1) is loaded by the weight of the user, an adjustment of the cable (7) translates into an adjustment of the transmission mechanism (10).

3. Office chair according to claim 1 or 2, characterised in that when the office chair (1) is unloaded, an adjustment of the cable (7) translates into an adjustment of the pinion (8).

Office chair according to any one of claims 1 to 3, characterised in that the transmission mechanism (10) comprises a rotatable ring (10') connected to the cable (7), and which rotatable ring (10') is drivingly connected to the pinion (8) by means of at least one spring (11) connected to the rotatable ring (10'), said spring being connected to the pinion (8) for absorbing rotation of the ring (10') relative to the pinion (8) when the chair (1) is loaded, and said spring (11) ensuring that the pinion (8) follows the rotation of the ring (10') when the chair (1) is unloaded.

5. Office chair according to one of claims 1 to 4, characterised in that the cable (7) is a Bowden cable.

6. Office chair according to one of claims 1 to 5, characterised in that the rack system comprises one pinion (8) and two racks (9), a gear wheel (13) being provided between one of the racks (9) and the pinion (8) to ensure the symmetrical operation of both racks (9).