GB2348124A

GB2348124A - Posture chair with tilting seat.

Info

Publication number: GB2348124A
Application number: GB9907105A
Authority: GB
Inventors: Zaki Kanaan
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-26
Filing date: 1999-03-26
Publication date: 2000-09-27
Also published as: GB9907105D0

Abstract

A chair of the type comprising a seat 19 and a knee support 27 mounted on a base has the seat pivotally mounted 23 so that the seat is tiltable in response to movement of the user. Preferably the knee support is similarly mounted 31. Means 19a, 21a, 27a, 29a may be provided to limit the range of tilting movement. Biasing means may be provided co-operating with the seat so that the seat tilts to follow the user as the user bends forwards. This biasing means could be in the form of a simple spring (35, Fig. 3) or a piston and cylinder assembly (43, Fig. 4). The chair is designed particularly for use by a dentist.

Description

Chair The present invention relates to a chair, in particular, but not exclusively, a dentist's chair in which a dentist sits while working on a patient's teeth.

Chairs are known which have a seat which is mounted at a fixed angle to the floor and a knee support which is mounted at a fixed angle to the floor such that the knees of a user can rest on the knee support while the user is seated on the seat. Such chairs are commonly known as kneeling chairs. The kneeling chair is designed so that when a user is seated on the seat, the user's body adopts a good posture which can help prevent backache. The kneeling chair is particularly suited to situations where the user sits still, for example when working at a computer, watching television or reading a book.

Kneeling chairs are not, however, well-suited to situations in which a user is carrying out a task which requires the user to move. For example, when a dentist is working on a patient's teeth, the dentist has to be able to move so that the mouth can be visually inspected from many different angles.

An object of the present invention is to provide a chair, having a knee support, in which a user is able to carry out tasks which require movement.

According to an aspect of the present invention, there is provided a chair comprising: a base; a seat mounted on the base; and a knee support mounted on the base, the seat and the knee support being arranged such that the knees of a user can rest on the knee support when the user is seated on the seat, wherein the seat is mounted on the base such that the seat is tiltable in response to movement by the user.

According to another aspect of the present invention, there is provided a dentist's chair comprising: a base; a seat mounted on the base; and a knee support mounted on the base, the seat and the knee support being arranged such that the knees of a user can rest on this knee support when the user is seated on the seat, wherein the seat is mounted on the base such that the seat is tiltable in response to movement by the user.

Preferably the chair further comprises co-operating means mounted on the base and the seat which are arranged to engage each other to limit the range of tilting of the seat which helps prevent the possibility of a user slipping off the seat.

In an embodiment, the knee support is also tiltable in response to movement by the user as this aids the user to find a comfortable seating position for different angles of tilt of the seat. Preferably, the knee support and base have co-operating means for limiting the range of tilting.

Preferably the seat and the knee support are mounted on the base via respective different telescopic members such that the heights of the seat and the knee support can be adjusted in accordance with the height of the user.

Preferably the seat further comprises biasing means arranged to provide a force which acts against the weight of a user so that when a user leans forward the seat remains in contact with the user. The biasing means may conveniently be provided by a spring or a piston-andcylinder assembly.

Preferably, the base of the chair is arranged to define an area in which a foot-pedal can be positioned for use by a user when the user is seated on the seat.

Exemplary embodiments of the present invention will now be described with reference to the accompanying figures in which: Figure 1 illustrates a dentist sitting in a chair according to a first embodiment of the invention while examining a patient; Figure 2 is a side view of a person sitting in a chair according to a first embodiment of the present invention; Figure 3 is a side view illustrating the seat of a second embodiment of the present invention; and Figure 4 is a side view illustrating the seat of a third embodiment of the present invention.

A first embodiment of the invention will now be described with reference to Figures 1 and 2. As shown in Figure 1, a chair according to the invention, generally indicated at 1, can be used by a dentist 3 (shown in phantom lines) while examining the teeth of a patient 5 (shown in phantom lines). The dentist 3 is able, while seated in the chair 1, to use a foot-pedal 7 for turning ON and OFF a dental drill (not shown).

The chair 1 has a base comprising an elongate central support member formed by two rod-like members 13a, 13b connected to each other via a sleeve joint. A screw 16 passes through the rod-like member 13b so that the tip of the screw 16 presses against the other rod-like member 13a to hold the rod-like members 13a, 13b in a fixed position relative to each other. The screw 16 is rotatable by a user to move the tip of the screw 16 away from the rod-like member 13a and thus allow telescopic movement between the two rod-like members 13a, 13b.

The central support member 13a, 13b has at each end 14a, 14b a pair of rod-like foot members lla and llb, llc and lld extending transversely to the support member 13 so that each pair of foot members lla and llb, llc and lld subtends therebetween an angle less than 180 degrees. Each foot member lla, llb, llc and lld carries a castor 9 so that the chair 1 rests on the castors 9 and can be pushed easily over flat ground.

A strut 15 extends between each pair of foot members lla and llb, llc and lld to provide additional stability.

As can be seen in Figure 1, the foot members 11 and the central support member 13 are arranged such that a space is formed adjacent the central support member 13 in which the foot-pedal 7 can be placed.

A respective hollow member 17a, 17b is connected to each end 14a, 14b of the central support member 13. The hollow members 17a, 17b project upwardly and perpendicularly from the central support member 13 when the chair 1 is in use.

A seat 19 on which a user can sit is connected to a seat support member 21 via a pivot pin 23, as can best be seen in Figure 2. The seat 19 may, for example, have a form similar to a bicycle saddle although other known forms of seat may be used. The cross-section of the seat support member 21 is such that the seat support member 21 fits within the hollow member 17a. A screw 25 passes through the hollow member 17a so that the tip of the screw 25 presses against the seat support member 21 to hold the seat support member 21 in a fixed position relative to the hollow member 17a. The screw 25 can be rotated by a user to move the tip of the screw 25 away from the seat support member 21 and thus free the seat support member 21 for telescopic movement within the hollow member 17a to enable the user to adjust the height of the seat 19.

The seat 19 and seat support member 21 may carry cooperating members 19a and 21a to limit the range of movement of the seat 19.

A knee support 27 is similarly connected to a knee support member 29 by a pivot pin 31. The cross-section of the knee support member 29 fits within the hollow member 17b. A screw 33 passes through the hollow member 17b so that the tip of the screw 33 presses against the knee support member 29 to hold the knee support member 29 in a fixed position relative to the hollow member 17b.

The screw 33 can be rotated by a user to move the tip of the screw 33 away from the knee support member 29 and thus free the knee support member 29 for telescopic movement with the hollow member 17b to enable the user to adjust the height of the knee support 27.

The knee support 27 and knee support member 29 may carry co-operating members 27a and 29a to limit the range of movement of the knee support 27.

Enabling the seat 19 to tilt about a pivot axis defined by the pivot pin 23, provides the advantage that a user, such as the dentist 3 illustrated in phantom lines in Figure 1, can move forwards to bend over a patient as shown in Figure 1 and backwards again without greatly changing the angle between the seat 19 and his back.

Allowing the knee support 27 to tilt about a pivot axis defined by the pivot pin 31 helps the user to find a comfortable knee rest for different angles of tilt of the seat 19.

The sleeve or telescopic joints between the two rod-like members 13a, 13b forming the central support member, the knee support member 29 and the hollow member 17b, and the seat support member 21 and hollow member 17a enable the chair to be adjusted to fit the dimensions of a particular user. Further, the sleeve joints allow the chair to be adjusted into a storage position in which the size of the chair is reduced to a minimum.

A second embodiment of the invention will now be described with reference to Figure 3. The second embodiment differs from the first embodiment only in the manner in which the seat 19 is mounted on the seat support member 21.

As shown in Figure 3, the seat 19 is mounted on the seat support member 21 via a pivot pin 23 as in the first embodiment. A spring 35 is connected between the seat 19 and the seat support member 21. The spring 35 provides a force to bias the seat to move in the direction marked by the arrow A to counter-act the weight of a user so that as the user bends forward and thus moves against gravity, the spring 35 causes the seat 19 to move with the user so that the user remains seated on the seat. A lug 37 projects, from the seat 19 such that when a user sits on the seat 19 and the seat 19 is tilted in the direction opposite to that of the arrow A, as shown in full lines in Figure 3, the lug 37 engages a stop 39 which projects out of the seat support member 21 to limit the rotational movement of the seat 19. The seat 19 is also shown in dashed lines in Figure 3 in the rest position which the seat 19 adopts when no user is seated and in which the spring does not exert a force on the seat 19.

A third embodiment of the present invention will now be described with reference to Figure 4. The third embodiment differs from the first embodiment only in the manner in which the seat 17 is mounted on the seat support member 19.

In the third embodiment, the seat 19 is mounted to the seat support member 21 via a pivot pin 23 as in the first and second embodiments. A fixed arm 41 projects from the seat support member 21 and a pneumatic or hydraulic piston-and-cylinder assembly 43 is connected between the fixed arm 41 and the seat 17, with in this example the cylinder 43a being connected to the fixed arm 41 and the piston 43b being connected to the seat 17. The seat 19 is shown in full lines in Figure 4 in the rest position in which no user is present.

When a user sits on the seat 19, the seat 19 tilts as shown in dashed lines in Figure 4 and the piston is pushed into the cylinder until a flange 45 at the end of the piston engages the top of the cylinder to prevent further rotational movement. The pressure built up in the fluid of the piston-and-cylinder assembly is released as the user tilts the seat 19 in the direction marked by the arrow B and the piston-and-cylinder assembly 43 provides a force in the direction marked by the arrow B so that the seat 19 moves with the user thereby aiding the movement of the user. The piston is trapped within the cylinder and thus the total range of pivotal movement is limited by the range of movement of the piston.

A number of modifications can be made to the abovedescribed embodiment without departing from the concept of the invention.

For example, the seat biasing arrangement shown in Figure 3 or 4 may also be applied to the knee support 27.

It will be appreciated that many variations may be made to the arrangement of the foot members 11, central support member 13 and hollow members 17a and 17b. For example, further struts may extend between opposed ones lla and llc, llb and lld of the foot members 11 to provide further stability. The four struts may, in this case, define a circular frame or hoop bounding the base. Alternatively, five or more foot members 11 may be used to increase stability. Further, the central support member 13 may be removed such that all of the foot members 11 are connected together and extend radially from a single hollow member 17 projecting upwards from the connection point. In all these cases, room can still be made for the foot pedal 7.

If adjustment of the height of the seat 19 and the knee support 27 is not required, the hollow members 17a, 17b can be removed and the seat support member 21 and the knee support member 29 can be connected directly to the central support member 13. Similarly if adjustment of the separation of the seat and knee support is not regarded, then the central support member 13 may be formed as a single member of fixed length. Also, the knee support 27 need not be tiltable but may be fixed in place. It is, however, advantageous that the angle of the knee support 27 in relation to the floor can be adjusted to conform with the dimensions of different users. For example, a screw can be passed through the knee support member 29 to press into the pivot pin 31 to hold the knee support member 31 at a fixed angle when in use, the screw being rotatable by a user when the chair is not in use to free the pivot pin 31 and enable the angle of tilt of the knee support member 27 to be adjusted.

The skilled person will realise that although the seat 19 is connected to the seat support member 21 in all the embodiments via a pivot pin, other arrangements could be used which still enable the seat 19 to tilt. For example, the seat 19 can be connected to the seat support member 21 using a plurality of springs such that, as a user moves and redistributes his weight the plurality of springs are compressed by varying amounts which leads to tilting of the seat 19. This also applies to the knee support where the knee support is tiltable Although the embodiments have been described in the context of a chair in which a dentist sits while working on the teeth of a patient, chairs according to the present invention can be of use in many other applications in which tasks are being carried out which require movement by the user. For example, chairs embodying the invention can be used by dental technicians, neurosurgeons and pathologists and by people working at sewing machines.

Claims

Claims 1. A chair comprising: a base; a seat mounted on the base; and a knee support mounted on the base, the seat and the knee support being arranged such that the knees of a user can rest on the knee support when the user is seated on the seat, wherein the seat is mounted on the base such that the seat is tiltable in response to movement by the user.
2. A dentist's chair comprising: a base; a seat mounted on the base; and a knee support mounted on the base, the seat and the knee support being arranged such that the knees of a user can rest on the knee support when the user is seated on the seat, wherein the seat is mounted on the base such that the seat is tiltable in response to movement by the user.
3. A chair according to claim 1 or 2, further comprising co-operating means mounted on the base and the seat, wherein the co-operating means are arranged to engage each other to limit the range of tilting of the seat.
4. A chair according to any preceding claim, wherein the knee support is tiltable in response to movement by the user.
5. A chair according to claim 4, wherein the knee support and base have co-operating means for limiting the range of tilting of the knee support.
6. A chair according to any preceding claim, wherein the seat and the knee support are mounted on the base via respective different telescopable members such that the heights of the seat and the knee support can be adjusted.
7. A chair according to any preceding claim, further comprising biasing means co-operating with the seat to provide a force such that the seat tilts to follow the user as the user bends forward towards the knee support.
8. A chair according to claim 7, wherein the biasing means is a spring.
9. A chair according to claim 7, wherein the biasing means is a piston-and-cylinder assembly.
10. A chair according to any preceding claim, wherein the base of the chair is arranged to define an area in which a foot-pedal can be positioned for use by a user when the user is seated on the seat.
11. A chair according to any preceding claim, wherein the base is arranged so as to enable the separation of the seat and knee support to be adjusted.
12. A chair substantially as described hereinbefore with reference to, or as illustrated in, the attached drawings.