AU749628B2

AU749628B2 - Improvements in/or relating to chairs

Info

Publication number: AU749628B2
Application number: AU42657/00A
Authority: AU
Inventors: Mark Pennington
Original assignee: Formway Furniture Ltd
Current assignee: Formway Furniture Ltd
Priority date: 1995-08-30
Filing date: 2000-06-23
Publication date: 2002-06-27
Anticipated expiration: 2016-08-30
Also published as: NZ272892A; AU6891296A; AU4265700A; DE19680835T1; WO1997007717A1

Description

91 Regulation 3.2

AUSTRALIA

PATENTS ACT, 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT r r

ORIGINAL

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: FORMWAY FURNITURE LIMITED Mark PENNINGTON A J PARK, Level 11, 60 Marcus Clarke Street, Canberra ACT 2601 IMPROVEMENTS IN/OR RELATING TO CHAIRS The following statement is a full description of this invention, including the best method of performing it known to me/us -la- IMPROVEMENTS IN/OR RELATING TO CHAIRS This invention relates to chairs and in particular a mounting for a chair back.

BACKGROUND

There is increasing recognition that ergonomic chairs are important for user comfort and health. An important aspect in such a design is the shape and movement of the back. In essence the chair back should work in harmony with the movement of the users back. Chairs with a rigid connection between the seat and back are not, ergonomically satisfactory.

It is an object of the present invention to provide a mounting for a chair back which S. will allow for ergonomically acceptable support and movement of the chair back.

000 o PRESENT INVENTION 20 In accordance with an aspect of the present invention, there is provided a chair including: o a supporting base; a seat portion supported above the supporting base; a back portion; and an arm arrangement interconnecting the back to the supporting base and/or the seat, the i: arm arrangement including: an armrest portion; an interconnecting portion extending between the armrest portion and the supporting base or between the armrest portion and 0 00 25 the seat portion; and a torsion means comprising a first high tensile metal strap which is bent to an included angle, the torsion means being connected to the back portion on one side of the included angle and, at the other side of the included angle, the torsion means :0 being in connection with or forming part of the armrest, such that upon the chair occupant leaning back on the back portion, the arm arrangement allows the back portion to lower relative to the seat portion with the torsion means adapted to undergo a twisting or torsional action.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

DRAWING DESCRIPTION One preferred form of the invention will now be described with reference to the accompanying drawings in which:p S Figure 1 is a pictorial front view of one embodiment of a chair including a chair back 40 -mounting according to the present invention.

"FIC& Figure 2 is a side view of Figure 1.

-2- Figure 3 is a rear view of Figure 1.

Figure 4 is a pictorial view of an alternative chair including a chair back mounting according to the present invention.

Figure 5 is a yet further alternative chair including a chair back mounting according to the present invention.

Figure 6 is a top view of the chair back mounting according to the present invention.

Figure 7 is a side view of Figure 6.

Figure 8 is a bottom view of the chair back mounting.

Figure 9 is a pictorial top view of a chair arm incorporating the chair back mounting 20 according to the present invention.

o Figure 10 is an underneath view of Figure 9.

Chairs having a chair back mounting according to the present invention which have been ergonomically designed may be presented in a number of different configurations and an exemplary range only has been illustrated in the present invention.

o. *o PREFERRED

EMBODIMENT

1 In Figure 1 the chair 1 has a back 2 supported on arms 3 and 4 extending from the chair frame 5 which continues down to form the front leg 6 with the rear leg 7 extending from underneath and providing support for the seat 8. Arms 3 and 4 are attached to the chair back 2 with a space left between the points of connection with the back as.is more clearly visible in Figure 3. While this is desirable for aesthetic reasons there is no structural reason why the mounting according to the present invention could not be formed to extend across the back of the chair.

As indicated above various chair configurations can be produced using the present invention and in Figure 4 a modified seat frame 9 is shown. In this chair the back 2b -3is similarly supported by the arms 3b and 4b as with the previous chair but with a different base support 9 as illustrated.

The chair Ic as illustrated in Figure 5 is an executive style chair with a typical swivel base 10 supporting the seat 8c. The larger back 2c is supported on arms 3c and 4c again in a manner similar to that with the other chairs but with the arms extending down to attach to part of the frame supporting the seat 8c.

The various chairs have been illustrated to indicate that the present invention can be applied to a wide variety of chairs but will require a degree of modification in the way the mounting is attached to the chair frame but this will be clearly apparent to a person skilled in the manufacture of chairs. The mounting illustrated is particularly intended for chairs illustrated in Figures 1 to 4.

The mounting 11 according to the present invention will be incorporated in a chair arm :.Z S: 20 adapted to be supported on the chair frame and connected to the chair back as So:. previously indicated. The mounting 11 includes a support member 12 which is adapted in use to form part of or be attached to a chair arm and connected to the chair frame.

A preferred form of the mounting as illustrated in particular detail in Figures 6-8 has the support member 12 shaped and designed to be incorporated in a moulded polyurethane chair arm with a point of connection through the support member 12 to engage the chair frame.

The mounting 11 is completed by a torsion means 13 which is formed in the preferred embodiment by two rectangular high tensile steel straps 14 and 15. The straps are connected together at the positions of contact with the chair back and with the support means 12 but are otherwise unconnected between these points of contact. It has been found important to provide such a construction because the internal stresses within the torsional member are such that significantly increased life is achieved by adopting the two strap configuration. This is because the straps act independently and the internal stresses within the straps are within acceptable working tolerances of the material. 1065 high tensile spring steel may be used for the torsion straps.

It would be possible to produce a configuration with more than two straps, but the increased cost is unlikely in most circumstances to be matched by any increase in efficiency.

Equally it would be possible to produce the torsion means as a single rectangular high tensile steel strap but at a cost of significantly reduced life expectancy. For this reason the invention is preferably provided with the two strap configuration.

The high tensile steel straps_4-and 15 are shaped to form an included angle of greater than right angles with the preferred range being between 105 and 120 degrees.

Ergonomically acceptable movement of the chair back is possible with the point of contact of the mounting means and the chair back being at or adjacent to the lumbar region of the user, and the included angle being substantially 107 degrees.

The point of contact between the mounting means 11 and the chair back is through the 20 high tensile steel straps 14 and 15 by attachment studs fitted through apertures 18 and 19 in the straps. The straps are attached to the support member 12 by bolts 16 and 17.

.'The angular configuration of the straps can be varied within reasonable ranges although it is desirable to preserve the configuration as described and illustrated if the desired ergonomic advantage is to be achieved. This is achieved because when a user applies force to the seat back causing a twisting action the back 2 will move about the mounting means. The connection between the mountings and the chair back is located at or towards the lumbar region of the user's back and the mounting provides a natural S• .movement of the chair back for the user. Because of the angle at which the torsion straps are arranged the rearward movement also causes the back to move down towards the seat. This is a movement which is ergonomically acceptable and comfortable for the user.

The mounting has been tested through 200,000 cycles with a 400 newton force applied in the direction the seat backward movement in use. This testing did not result in any failure or noticeable deterioration in the mounting for the chair back.

As stated above the arm member 12 as illustrated is designed to be incorporated in a moulding which will form the armrest of the chair. The curved extension or tongue is thus shaped to conform with the shape of the armrest and the apertures 21 are provided to give an increased bonding between the moulding and the arm support. A threaded stud 22 is provided as the support between the completed armrest including the mounting according to the present invention and the chair frame as illustrated in Figures 1 through to 4.

The completed arm rest 3 or 4 including the mounting is illustrated in Figure 9. The mounting studs 23 pass through the apertures 18 and 19 in the strap and the apertures 18a and 19a in the completed moulded arm rest and back mounting to engage in threaded sockets in the chair back. The under surface of the moulding has formed therein a slot 24 which accommodates the tubular frame of the chair with the stud 22 engaging through an aperture in the frame and with a nut locating the moulding in place.

One embodiment of the invention able to be incorporated in a chair arm moulding has been described but the chair design will influence the way in which the mounting is applied while preserving the concepts of the invention as set out above.

0 The advantage of the mounting is that the chair has the back supported to provide *J movement of the chair back ergonomically consistent with the seated body position.

Claims

1. A chair including: a supporting base; a seat portion supported above the supporting base; a back portion; and an arm arrangement interconnecting the back to the supporting base and/or the seat, the arm arrangement including: an armrest portion; an interconnecting portion extending between the armrest portion and the supporting base or between the armrest portion and the seat portion; and a torsion means comprising a first high tensile metal strap which is bent to an included angle, the torsion means being connected to the back portion on one side of the S included angle and, at the other side of the included angle, the torsion means being in :15 connection with or forming part of the armrest, such that upon the chair occupant leaning S back on the back portion, the arm arrangement allows the back portion to lower relative to the seat portion with the torsion means adapted to undergo a twisting or torsional S action. 2XI1 2. The chair as claimed in claim 1 wherein the torsion means is connected to the back at a location corresponding to the lumbar region of the seat occupant.

3. The chair as claimed in claim 1 or claim 2 wherein the torsion means is an L- shape with one end being in connection with or forming part of the armrest portion and the other end being connected to the back portion.

4. The chair as claimed in claim 3 wherein there are two such armrest arrangements on either side of the chair.

5. The chair as claimed in claim 1 or claim 2 wherein the first high tensile metal strap has a second included angle to form a central portion extending across the back portion and two end portions, with the central portion of the torsion means being connected to the back portion and the two end portions forming part of or being in connection with respective armrest portions on opposite sides of the chair. -7-

6. The chair as claimed in any one of the preceding claims wherein the torsion means additionally comprises a second high tensile metal strap in substantially the same form as the first high tensile metal strap and lying adjacent the first high tensile metal strap.

7. The chair as claimed in claim 6 wherein the first and second high tensile metal straps are interconnected at their points ofconnection to the back portion and the or each armrest portion, being otherwise unconnected between these points.

8. The chair as claimed in any one of the preceding claims wherein the or each included angle in the torsion means is greater than a right angle.

9. The chair as claimed in claim 8 wherein the or each included angle lies in the range of 105 to 120 degrees. S 10. The chair as claimed in claim 9 wherein the or each included angle is 107 degrees.

12. The chair as claimed in any one of the preceding claims wherein a moulded cover is incorporated into the arm arrangement.

13. The chair as claimed in any one of the preceding claims wherein the seat portion and back portion are separate. a

14. The chair substantially as hereinbefore described with reference to Figures 1 to 3, 6 to 9 or as modified by either Figures 4 and Dated this 28th Day of February 2002 By their Patent Attorneys AJPARK On behalf of the Applicant Per: