GB2565537B

GB2565537B - Office chair

Info

Publication number: GB2565537B
Application number: GB1712912.3A
Authority: GB
Inventors: Jones Mark
Original assignee: Profim Sp Zo O
Current assignee: Profim Sp Zo O
Priority date: 2017-08-11
Filing date: 2017-08-11
Publication date: 2019-08-14
Anticipated expiration: 2037-08-11
Also published as: GB201712912D0; GB2565537A

Description

Office Chair

This invention relates to a chair, specifically to an office chair, comprising a support panel for a seat element and a substantially vertical back support element. An office chair allows the user to influence and adjust his or her seating dynamic to varying degrees.

In contrast to a rigid chair, where there is no provision for changing the relative positions of seat to backrest, the office chair has provision for adjusting those relative positions according to the requirements of the user.

The mechanisms provided in an office chair serve to encourage the user into a dynamic sitting behaviour. This entails changing his or her position regularly, thus avoiding muscular discomforts such as cramp or fatigue and thus allowing the user to sit for longer periods without experiencing the normal problems associated with prolonged sitting, or at least substantially reducing those effects.

Well known mechanisms for adjusting seating positions on office chairs allow for the tilting of the backrest, the seat panel or even a combination of both.

An example of such a chair mechanism is know from EP2725943 Al (L & P Property Mgt) which discloses an office chair which accommodates some of the user’s movements and whose seat panel tilts and moves backwards when the user leans backwards thus tilting the backrest.

To improve this situation a side to side/left to right motion can be added which promotes movement even further.

More recent improvements allow for the sideways rocking or “twisting” of the seat and chair. Such an arrangement is known from the German ‘Offenlegungsschrift” DEI02014006058 (Grupo Forma) which discloses an office chair wherein the seat panel and the backrest can twist sideways thus allowing the user to rock sideways.

However, this disclosure involves a rigid connection between the seat panel and the backrest such that the seat and the backrest have to move together. Such an arrangement has been shown not to be favoured by many users. A good office chair seating solution benefits the chair users by providing motion, this is to ensure that the chair users are not static for long periods of time as this is bad for the chair users’ health.

One instance of where this movement is limited is for example if the chair user movement is limited to forwards & backwards then they drop something & suddenly reach for it. After being static for a long period sudden movement can lead to back injury.

The present invention discloses an office chair which alleviates the above problems and disadvantages.

An independent seat & back twist allows for user preference. The front connection is a ball joint located in the centre plane of the seat. This ball joint is formed from two half spheres enclosed in a complementary shaped housing. This arrangement essentially creates a 360 degree pivot around the centre point of said ball joint.

The half spheres are mounted on the top surface of seat element (3) and the housing surrounding the half spheres is mounted under the chair seating panel, thus allowing the latter to twist sideways when the user leans sideways.

The rear of the seat is essentially floating on two compression springs spaced evenly away from the central plane (these could be any spring type, rubber, leaf spring etc.). These compression springs may rest in spring pockets lodged in the seat element into which pockets the compression springs may recede when coil springs are used.

The resulting motion is best described as a rolling motion where the tilting motion is strongest at the rear of the chair seating panel and reduces in amplitude the nearer it gets to the front of that panel. A useful option would be to include a means for the user to lock the twisting motion, hence precluding any sideways twisting of the chair seating panel when it is not wanted.

Since it is preferable to have chair controls at the front of the seat, for easy manipulation by the user, such a locking option should be operable at the front or the front side of the chair seating panel.

This option can be realised by putting a sliding block either side of the ball joint which sliding blocks can be moved toward the centre of the seat panel or away from it, thus either increasing or reducing the effective space between the underside of said chair seating panel and said seat element.

At the rear of the seat, as it is essentially floating, two items could be added: guides to align the seat left to right. These could be profiled to shape the twist to the desired shape, i.e. conical surfaces could be added, if the twist were desired to be exactly conical.

Tie straps either side of the central point of the seat element are required to stop the seat from flipping over when leaning to the side. These tie straps can vary in form, they could be screws/bolts, wires or even integrated hook features which are the preferred realisation. Such straps could also be used at the Front of the Seat if required for strength purposes.

Statement of the invention

The invention discloses an office chair comprising a seat element (3) mounted movably on a fixed support element (1) and a back support element (2), which arrangement simultaneously allows the seat element (3) to move and tilt backwards when the user leans backwards and which seat element (3) carries the chair seating panel (4) in such a way that when the user leans to a side, said chair seating panel (4) tilts to the same side according to the user’s movement and independently of said chair’s back element (2) whereby said tilting is effected by a sideways tilting mechanism comprises a ball joint (5) at the front of said chair seating panel (4) and two springs (6,7) at the rear.

Description of the drawings

Fig 1 shows a side view of the seat support structure without the seating panel

Fig 2 shows a side view of the chair seating panel in place on the support structure

Fig 3 shows a side view of the seat support structure with the front ball joint and the rear spring

Fig 4 shows the same view as fig with the seating panel in place

Fig 5 and Fig 6 show a front view of the seat highlighting the front ball joint in relaxed position and in tilted position

Fig 7 and Fig 8 show a rear view of the seat with the springs relaxed and in sideways tilt

Fig 9 shows the preferred realisation or the rear ties

Sheet 1 and figure 1 shows the basic support structure of the chair. The seat element (3) which carries the chair seating panel is supported by a fixed element (1) to which a back element (2) is hinged and said seat element (3) is hinged to both the fixed element (1) and the back element (2).

This basic arrangement enables the chair to be rocked backwards and apart from the back rest declining when the user leans back, the seat panel also moves backwards and its rear end also tilts downwards. Thus giving the user a pleasant and relaxing position.

This figure also shows at (5) the front support for the chair seating panel in the shape of a ball joint and the rear support in the shape of two springs on which the rear end of the chair seating panel floats.

Sheet 2 and figure 2 shows a similar elevational view with the chair seating panel in place and illustrating the rear seat panel springs on which it floats.

Sheet 3 and figure 3 shows the seat element with the forward ball joint (13) and one of the rear spring pockets (8,9) in a section which is partially through the centre of the seat element.

Figure 4 on sheet 4 shows the basic construction of the chair with the chair seat panel in place. Illustrated are the two halves of the front ball j oint (10,11) in their housing (not stressed) and one of the pockets for the springs (6,7).

Figure 5 on sheet 5 shows the unstressed position of the front ball joint with the seat in a horizontal position whilst

Figure 6 on the same sheet shows the chair seat panel tilted to one side and the front ball joint stressing its housing.

Sheet 6 shows comparable positions with focus on the rear end of the chair seating panel.

Figure 7 shows the rear springs in rest position with the seat panel horizontal and figure 8 shows the seating panel twisted sideways and hence one of the springs being compressed and the other being stretched.

Finally figure 9 shows the preferred realisation of the ties between the chair seating panel and the seat element. These ties comprise a hook depending from the chair seat panel and engaging a second hook attached to the seat element limiting the amount of tilt by physical contact of said two hooks at the point of maximum tilt.

While it is acknowledged the drawings only represent one particular realisation of the invention, it is stressed that they are in no way limiting on possible variations on those realisations such as different springs at the back and different arrangements for the ball joint at the front of the chair seating panel.

Claims

Amended claims

1. An office chair comprising a seat element (3) mounted movably on a fixed support element (1) and a back support element (2), which arrangement simultaneously allows said seat element (3) to move and tilt backwards when the user leans backwards and which seat element (3) carries a chair seating panel (4) in such a way that when the user leans to a side, said chair seating panel (4) tilts to the same side according to the user’s movement and independently of said chair’s back element (2) whereby said tilting is enabled by a sideways tilting mechanism comprising a ball joint (5) at the front of said chair seating panel (4) and two springs (6,7) at the rear.

2. An office chair according to claim 1 wherein said ball joint (5) at the front of said chair seating panel (4) consists of two half spheres (10, 11) mounted on said seat element (3).

3. An office chair according to claim 2 wherein said ball joint (5) sits in a housing (13) whose inside is shaped to match said two half spheres (10,11) of said ball joint (5) and wherein said ball joint forms a 360 degrees pivot around its centre.

4. An office chair according to claim 1 wherein said two springs (6,7) are compression springs on which the rear of the chair seating panel (4) rests.

5. An office chair according to claim 4 wherein each of said springs (6,7) rest in a retaining pocket (8, 9) which retaining pockets are set into said seat element (3) spaced equally on either side of the centre of said seat element (3).

6. An office chair according to claim 5 wherein said springs are chosen from coil, leaf or rubber springs.

7. An office chair according to claim 1 to 6 wherein the maximum tilt of said chair seating panel (4) is determined by a pair of ties connecting the underside of said chair seating panel with said seat element and positioned equidistant outboard from said springs (6,7).

8. An office chair according to claim 7 wherein each of said ties comprises two hooks which engage with each other in such a way that the tilt of the said seating panel is limited by said hooks touching.

9. An office chair according to claim 7 wherein said ties comprise a looped strap whose first end is fixed to the underside of said chair seating panel (4), said strap passing through a hole in said seat element (3) and returning through a second hole in said seat element (3) to said under side of said chair seating panel (4), thus limiting angle of upward movement of the corresponding side of said chair seating panel (4).

10. An office chair according to claim 7 wherein said ties are single straps with one end fastened to the underside of the chair seating panel (4) and the other to the top of the seat element (3).

11. An office chair according to claim 8 wherein stops, fitted to the top of said seat element (3), are provided for limiting the descent of the opposite side of said panel (4).