GB2329578A - Seat with pivotable seat back - Google Patents

Abstract

A seat has a seat back 13 having a frame member 17 carrying a seat back squab 23, the frame member being pivotable about a horizontal axis x---x. This axis is situated such that the vertical section of the seat back above the axis is less in vertical dimension than that of the section of the seat back below said axis. When the occupant leans on the seat back the lower part 23m presses into the lower back to provide support, without exerting undue pressure. By virtue of adjustable positions 21 a the height of the axis can be varied to suit persons of differing torso length.

Description

SEAT CONSTRUCTIONS This invention relates to seat constructions.

According to the invention, a seat construction has: (a) a seat platform; and (b) a seat back, being a seat back which comprises: (i) a frame part upstanding from said seat platform and fixed with respect thereto; (ii) squab cushion carrier means; and, (iii) hinge means, one hinge part of which is fixed with respect to the upstanding frame part such as to define, in said frame part, a site for a transverse hinge axis, and the other hinge part of which defines a transverse axis fixed with respect to said cushion carrier means and which is adapted to cooperate with said one hinge part such that the cushion carrier means is adapted to be supported with respect to said upstanding frame part for angular displacement about the transverse hinge axis formed at said site by said cooperative hinge parts; and, (iv) a squab cushion carried by said cushion carrier means; and in which: (c) the transverse axis defined by said other hinge part is so located as to divide said cushion carrier means lengthwise at a position such that the height of the portion of said carrier means upstanding above said transverse axis is less than the depth of the portion of the cushion carrier means dependant below said hinge axis; and, (d) the transverse hinge axis between the cushion carrier means and the frame part is so located in relation to the length of said cushion carrier means and the squab cushion carried thereon that, in use of the seat, pressure of the upper back region of a seat occupant, of appropriate torso length, upon that portion of the seat back which rises above said hinge axis, causes the seat back to rock about said hinge axis such as to bring a lower marginal part of said dependant portion of the squab cushion carrier means, and the correspondingly positioned squab cushion portion, to bear against the lower back region of such an occupant with a firm though not excessive pressure, being a pressure related to the position of the hinge axis along the length of the cushion carrier means.

In one hereinafter described embodiment of the invention, said one hinge part is one of a multiplicity of hinge parts, being a multiplicity of hinge parts respectively defining individual ones of a multiplicity of transverse axes fixed in said frame part at spaced apart positions thereof; and said other hinge part, that is to say, the hinge part defining a transverse axis fixed in said cushion carrier means, is readily attachable to and detachable from the frame part at any one of said multiplicity of hinge parts fixed in the frame part, thereby to provide a range of possible transverse hinge axes for the cushion carrier means.

In another hereinafter described embodiment, the upstanding frame part comprises a first, fixed, frame portion upstanding from the seat platform and a second frame portion constrained for displacement with respect to the first frame portion; and means operable to secure the second frame portion with respect to the first; and in which said second frame portion incorporates the hinge means defining said transverse axis fixed in the frame part; the hinge part fixed with respect to said squab cushion carrier arrangement is secured to said second, displaceable frame portion at said axis for angular displacement thereabout; and displacement of the second frame part with respect to the first serves to accommodate different lengths of torso of prospective occupants of the seat.

The foregoing and other aspects and features of a chair in accordance with the invention are hereinafter described with reference to the accompanying drawings in which: Fig.l shows, diagrammatically, in side elevation, a first chair configuration, said chair having a chair back incorporating squab cushion carrier means suited to an adult occupant for the chair; Fig.2 shows a corresponding chair configuration to that of Fig.l, but with the squab cushion carrier means suited to a child occupant for the chair; Fig.3 shows, diagrammatically, a front elevation of the chair back of Fig.l; Fig.4 shows, diagrammatically, a front elevation of the chair back of Fig.2; Fig.5 shows one side member of the upstanding frame part together with three cup elements each constituting one of a pair of elements each said pair serving to define a transverse axis fixed with reference to the frame part; Fig.6 shows at (a) and (b) alternative constructions for the squab cushion carrier means and the cushions carried thereby; Fig.7 shows, diagrammatically, a second chair configuration corresponding to that of Fig.l; Fig.8 shows, diagrammatically, a third chair configuration, being a variant of the chair configuration of Fig.7; Fig.9 is a diagrammatic representation of the plan view of the chair back of Fig.7; and, Fig.10 shows, diagrammatically, a detail of the arrangements of Figs.7 and 9.

A seat (whether to the configuration of Figs.l or 2 or that of Figs 7 or 8) has: (a) a seat platform 11; and (b) a seat back 13 comprising: (i) a frame part 15 upstanding from said seat platform 11 and fixed with respect thereto; (ii) squab cushion carrier means 17, being, in the examples, depicted as a body of substantially rigid sheet material; and, (iii) hinge means 19, one hinge part 21a of which is fixed with respect to the upstanding frame part 15 such as to define, in said frame part 15, a site for a transverse hinge axis, and the other hinge part 21b of which defines a transverse axis fixed with respect to said cushion carrier means 17 and which is adapted to cooperate with said one hinge part 21a such that the cushion carrier means 17 is adapted to be supported with respect to said upstanding frame part 15 for angular displacement about the transverse hinge axis X----X formed at said site by said cooperative hinge parts 21a, 21b; and, (iv) a squab cushion 23 carried by said cushion carrier means 17.

The transverse axis defined by the hinge part 21b is so located as to divide the cushion carrier means 17 lengthwise at a position such that the height of that portion 17s of said carrier means 17 upstanding above said transverse axis is less than the depth of the portion 17i of the cushion carrier means dependant below said hinge axis.

The position of the transverse hinge axis X----X between the cushion carrier means 17 and the frame part 15 is so located in relation to the length L of the cushion carrier means 17 and the squab cushion 23 carried thereon that, in use of the seat, pressure of the upper back region of a seat occupant, of appropriate torso length, upon that portion of the seat back which rises above said hinge axis X----X causes the cushion carrier means 17 and the cushion 23 carried thereby, to rock about the hinge axis X----X such as to bring a lower marginal part 25 of the dependant portion 17i of the squab cushion carrier means 17, and a correspondingly positioned lower marginal squab cushion portion 23m, to bear against the lower back region of such an occupant with a firm though not excessive pressure, being a pressure related to the position of the hinge axis X----X along the cushion carrier means 17 in its direction of length.

Except where the seat is to a bespoke size intended for the use of an occupant of known physique, it is desirable that the seat to either of the configurations diagrammatically illustrated be adjustable to accommodate a range of possible occupants.

In the seat configuration of Fig.l or 2, the one hinge part 21a is one of a multiplicity of pairs of aligned cup-form elements 21a, being cup-form elements respectively defining individual ones of a multiplicity of transverse axes fixed in said upstanding frame part 15 at spaced apart positions thereof; and said other hinge part 21b is constituted as two laterally aligned spigots, 27a, 27b, respectively, projecting from the sides of the body of sheet material of which, in the examples, the cushion carrier means 17 is constituted, said spigots being respectively readily receivable within and removable from a pair of aligned cup-form elements 21a at any one of said multiplicity of hinge parts fixed with respect to the frame part 15, thereby to provide a range of possible transverse hinge axes X----X for the cushion carrier means 17.

In the second seat configuration (Fig.7), the upstanding frame part 15 comprises a first, fixed, frame portion 15a upstanding from the seat platform 11 and a second frame portion 15b having a main body portion 27a and a cranked short end portion 27b, and being constrained for longitudinal displacement with respect to the first frame portion 15a; the second frame portion 15b of the frame part 15 has a multiplicity of spaced holes 29 therethrough and a pin 31 tethered to the first frame portion 15a is receivable within any of the holes 29 such as to permit the second frame portion 15b to be set at any position with respect to the first frame portion 15a within the range of the spaced holes 29. Suitably, the second frame portion 15b is telescopically slideable within the first frame portion 15a. The hinge 19 between the frame part 15 and cushion carrier means 17 is carried at the cranked end portion 27b.

The seat of Fig.8 differs from that of Fig.7 in that the second frame portion 15b of the upstanding frame part 15 has a slight backwards rake angle with respect to the first frame portion 15a.

As hereinbefore stated, the position of the transverse axis through the cushion carrier means 17, which axis is, in use, coincident with the hinge axis X----X, divides the cushion carrier means 17 and the squab cushion 23 carried thereby, into a superior portion 23s projecting above the transverse axis through the cushion carrier means and an inferior portion 23i of greater length than said superior portion 23s dependant below said transverse axis. With the cushion carrier means 17 hingedly connected to the frame part 15 at the axis X----X, the lesser length of the inferior cushion portion 23i provides that pressure exerted at the superior cushion portion 23s by the upper body region of a seat occupant gives rise to a reactive pressure between the marginal lower end portion 23m of the cushion 23 and the region of the back of the seat occupant, the lower back region, that is, to which support is to be given. By suitable choice of the position P of the transverse axis lengthwise of the cushion carrier means, the pressure between the lower end of the squab cushion carried thereby and the back portion to be given support, may be optimised to the occupant's need.

It has been assessed that the transverse axis through the cushion carrier means may occupy a position P ranging from between about 10mm below the top and, in the case of a seat for a child, such as that represented diagrammatically in Figs. 2 and 4, as little as 25mm above a notional transverse centre line, as L----L of the cushion carrier means 17.

The squab cushions 23 of each of the aforedescribed seats may be pre-formed cushions, typically as illustrated in Fig. 6(a) or (b), being fixed with respect to the squab cushion carrier means 17; or they may be removable cushions. The cushions 23 may be of any suitable construction, and may be filled with any suitable material, fibrous, gaseous or gel, for examples. They may be attached to the cushion carrier means 17 by any appropriate fixing, such as, for example, Velcro or like materials.

Claims (1)

1. A seat which has: (a) a seat platform; and (b) a seat back, being a seat back which comprises: (i) a frame part upstanding from said seat platform and fixed with respect thereto; (ii) squab cushion carrier means; and, (iii) hinge means, one hinge part of which is fixed with respect to the upstanding frame part such as to define, in said frame part, a site for a transverse hinge axis, and the other hinge part of which defines a transverse axis fixed with respect to said cushion carrier means and which is adapted to cooperate with said one hinge part such that the cushion carrier means is adapted to be supported with respect to said upstanding frame part for angular displacement about the transverse hinge axis formed at said site by said cooperative hinge parts; and, (iv) a squab cushion carried by said cushion carrier means; and in which: (c) transverse axis defined by said other hinge part is so located as to divide said cushion carrier means lengthwise at a position such that the height of the portion of said carrier means upstanding above said transverse axis is less than the depth of the portion of the cushion carrier means dependant below said hinge axis; and, (d) the transverse hinge axis between the cushion carrier means and the frame part is so located in relation to the length of said cushion carrier means and the squab cushion carried thereon that, in use of the seat, pressure of the upper back region of a seat occupant, of appropriate torso length, upon that portion of the seat back which rises above said hinge axis, causes the seat back to rock about said hinge axis such as to bring a lower marginal part of said dependant portion of the squab cushion carrier means, and the correspondingly positioned squab cushion portion, to bear against the lower back region of such an occupant with a firm though not excessive pressure, being a pressure related to the position of the hinge axis along the length of the cushion carrier means.

2. A seat as claimed in claim 1 in which said one hinge part is one of a multiplicity of hinge parts, being a multiplicity of hinge parts respectively defining individual ones of a multiplicity of transverse axes fixed in said frame part at spaced apart positions thereof; and said other hinge part, that is to say, the hinge part defining a transverse axis fixed in said cushion carrier means, is readily attachable to and detachable from the frame part at any one of said multiplicity of hinge parts fixed in the frame part, thereby to provide a range of possible transverse hinge axes for the cushion carrier means.

3. A seat as claimed in claim 1 in which said upstanding frame part comprises a first, fixed, frame portion upstanding from the seat platform and a second frame portion constrained for displacement with respect to the first frame portion; and pin and hole means operable to secure the second frame portion with respect to the first at any one of a multiplicity of spaced positions along said first frame portion; and in which said second frame portion incorporates the hinge means defining said transverse axis fixed in the frame part; the hinge part fixed with respect to said squab cushion carrier arrangement is secured to said second, displaceable frame portion at said axis for angular displacement thereabout; and displacement of the second frame part with respect to the first serves to accommodate different lengths of torso of prospective occupants of the seat.

5. Any one of the seats substantially as hereinbefore described with reference to the relevant Figure or Figures of the accompanying drawings.