WO1990000360A1

WO1990000360A1 - Seat

Info

Publication number: WO1990000360A1
Application number: PCT/SE1989/000320
Authority: WO
Inventors: Bo Hedlund; Ulf Bergquist
Original assignee: Fmg Filipstad Ab
Priority date: 1988-07-06
Filing date: 1989-06-06
Publication date: 1990-01-25
Also published as: FI901039A7; SE8802525L; SE8802525D0; AU3779589A; FI901039A0

Abstract

A seat comprises a seat portion (1) which is carried by a stationary support (2) and swivels about a shaft (10) located preferably centrally relative to the seat portion. The seat portion (1) is connected with the support (2) via at least a first guide means (6) which in per se known manner allows displacement of the seat portion relative to the support. The swiveling shaft (10) of the seat portion is positioned or settable eccentrically relative to the centre (C'') of the support (2), and between the movable seat portion (1) and the stationary support (2), there is mounted a preferably mechanical coupling (15) which positively and automatically effects the displacement of the seat portion relative to the guide means, as soon as the seat portion is caused to swivel about the shaft (10).

Description

SEAT

Technical field of the invention

The present invention relates to a seat comprising a seat portion carried by a stationary support, said seat portion swivelling about a shaft which is preferably centred on the seat portion, and being connected with said support via at least a first guide means which allows displacement of the seat portion relative to the support. Background of the invention Several types of machines, such as loading ex¬ cavators, agricultural tractors and forest machinery, are designed in such manner that the driver must be able to take various seating directions when operating the machine. In, for example, forest machines the driver must thus sit in one direction when moving the machine and in a quite reversed direction when using the implements of the machine. To make the working position in both cases as convenient and ergonomically correct as possible, the distance between the driver's seat and the hand controls and, respectively, the foot pedals must be adjustable to drivers of different sizes. Such adjustment can be effected by moving the seat and/or the controls. The most common way of fa¬ cilitating adjustment of the position of the seat is to mount the seat on a swivelling support and simul¬ taneously provide the seat with rails by means of which the seat portion can be displaced in the longi¬ tudinal direction of the support. If the swivelling support is positioned midway between the groups of controls in the two working positions, the same dis¬ tance between seat and controls is obtained, irrespective of the working position of the seat. Drivers of dif¬ ferent sizes can thus set a suitable fixed distance bv means of said rails. The rails can be mutually locked in any desired position by means of a locking mechanism. Also the swivelling motion can be locked in any desired direction. This type of seat is dis¬ closed in US patents 4,014,507 and 4,227,670. However, for the reasons mentioned below, previously known driver's seats of this type suffer in certain cases from considerable drawbacks.

Depending on the position of the seat portion on the rails, the size of the space needed for swivelling the seat portion about the centre of the support varies. This space can per se be provided if the space for the driver is sufficiently large. However, in many cases the remaining operational requirements set a limit to the size of the driver's cab. Above all the available width of the vehicle restricts the width of the driver's cab. An analysis of the ergonomical need for space in the driver's cab shows that the space needed for the driver and the seat when swivelled must be adjusted as effectively as possible in the position where the seat is set transversely of the longitudinal direction of the driver's cab, i.e. the position midway between the two opposite working posi¬ tions of the seat. It will thus be appreciated that the centre for swivelling the seat must conform to the centre of the space required for the driver and the seat, the driver's feet and lower parts of the legs being put in towards the seat. Brief description of the inventive idea

The present invention aims at obviating the above- mentioned drawbacks of previously known driver's seats in working machines and at providing, while maintaining a minimal size of the driver's cab, a space in front of the seat portion which from the ergonomic point of view is conveniently large, when the seat portion is set in one of the two working positions of the seat. According to the invention, this is achieved primarily in that the swivelling shaft of the seat portion is positioned or settable eccentrically relative to the centre of the support, and that between the movable seat portion and the stationary support or parts thereof, there is mounted a preferably mechanical coupling which positively and automatically effects the displacement of the seat portion relative to the guide means, as soon as the seat portion is caused to swivel about said shaft.

Further description of the prior art technique US patent 3,893,728 discloses a seat whose seat portion is mounted at the free end of a pivotable supporting arm and connected with a regulating arm lever which per se provides turning of the seat portion when moved between two separate points in a driver's cab (or in the opposite case, moving of the seat portion when turned). Such moving of the seat portion occurs, however, along a path in the shape of a circular arc, without the seat portion being movable relative to the support or the point of suspension. Thus, this seat has no guide means whatsoever along which the seat portion can be moved.

Moreover, US patent 3,964,713 discloses a seat with a seat portion whose swivelling shaft is eccentrically positioned relative to a central support, but said shaft is mounted in a fixed point in a transverse supporting arm which carries the seat portion on the support. The seat portion thus is individually turnable relative to the supporting arm and is independent of whether this is pivoted about the support or not. Thus, this seat has no guide means whatsoever, let alone a coupling which provides forced and automatic displacement of the seat portion relative to a guide means, as soon as the seat portion is caused to swivel about its shaft. Brief description of the accompanying drawings In the drawings : FIG. 1 is a perspective view of a seat according to the invention, FIG. 2 is a schematic cross-sectional view of the frame of the seat, FIGS 3-5 are simplified perspective views of the seat and its frame in three different settings perpendicular to each other, and FIG. 6 is a simplified and schematic top plan view illustrating the function of the invention. Detailed description of a preferred embodiment of the invention

The inventive seat comprises, as shown in Fig. 1, in addition to a seat portion designated 1 , a support 2 which via a base plate 3 is stationarily or nonrotatably mounted on the floor, preferably in the middle of the driver's cab. The support 2 can, in per se known manner

(not shown), be provided with means for spring suspension and vertical adjustment of the seat. A back rest 4 is connected with the seat portion 1 , and two arm rests 5 are connected with the back rest. As is best shown in Figs 2 and 3, there is mounted on the support 2 a first rail or guide means 6 comprising a fixed member 7 and a movable member 8, of which the latter is reciprocating relative to the first. The movable member 8 of the guide means 6 has the shape of a holder carrying a swivelling mount 9 which comprises a swivelling shaft 10 which in turn supports the seat portion 1. The swivelling shaft 10 is preferably located substantially centrally under the seat portion 1. At the lower end of the swivelling shaft 10, there is arranged a pivot arm which in its entirety is de¬ signated 11 and in the shown, preferred embodiment has the form of a second guide means comprising first and second parts 12, 13 which are displaceable relative to one another and mutually lockable in any desired position by optional means (not shown), for example a spring-actuated pawl adapted to engage into suitable recesses. By moving the first part 12 relative to the second part 13, the distance or eccentricity between the centre C of the shaft 10 and the centre axis C" of the support 2 can thus be varied. At the free end of the pivot arm 11 which faces away from the shaft 10 or at the guide part 13 of the pivot arm, there is mounted a carrier means 14 which in the embodi¬ ment shown consists of a first hinge of a pivotable link 15 having a second hinge 16 which is fixedly connected to the support 2, more precisely via a bracket 17 which projects laterally from the support.

With special reference to Fig. 3, it should be emphasised that the first guide means 6 is always fixedly or stationarily oriented in space, more pre¬ cisely in such manner that it extends in the direction between the front and rear ends of the driver's cab. The second guide means 11 is however pivotable in space, more precisely by swivelling of the seat portion 1 about the centre axis C.

Fig. 6 shows schematically a driver's cab 18 whose one longitudinal side wall is designated 19. A steering- wheel 20 symbolically illustrates the direction in which the driver must turn to move the vehicle, while the controls 21 illustrates symbolically the direction in which the driver must turn to operate the implements of the vehicle, for example a grapple or felling tool. When the vehicle is to be moved, the seat thus takes position A in Fig. 6 (corresponding to the position shown in Fig. 3), and for performing a working opera¬ tion, it takes position B (corresponding to the position in Fig. 5). An intermediate position C (corresponding to the one in Fig. 4) arises, when the seat is swivelled between positions A and B.

With reference to Figs 3-6, it is assumed that the seat or seat portion is to be swivelled through 180° from position A to position B. In its initial position A shown in Fig. 3, the seat portion is moved back to a maximal extent relative to the support 2, whereby the driver has a maximal space for the feet and the lower parts of the legs in the area in front of the seat portion. This maximal space is, of course, determined through the setting of the guide parts 12,13 relative to one another depending on the bodily constitution of the driver. The available space thus is smaller the smaller the distance or eccentricity between the centre axes C and C", and vice versa. If the seat portion 1 is now swivelled counter-clockwise according to Fig. 3, the pivot arm 11 formed of the guide parts 12 and 13 is caused to pivot counter-clockwise about the centre axis C. Since the hinge 14 is, by means of the link 15, positively guided along a path of motion extending transversely of the longitudinal direction of the guide means 6, the pivot arm 11 will, when pivoted, pull the holder 8 inwardly towards the centre axis C" of the support, such that after swivelling of the seat portion through 90°, its swivelling shaft 10 is positioned coaxially with the centre axis C" of the support in position C as shown in Fig. 4. When the seat portion is then swivelled from position C in Fig. 4 towards position B in Fig. 5, the link 15 again forces the hinge 14 to move inwardly towards the centre of the support, while the holder 8 is simul- taneously moved away from the support, whereby the seat portion is again moved out to the position shown in Fig. 5, which is maximally spaced from the centre of the support.

If the seat were connected in conventional manner with the support via a single hinge, the back rest 4 would describe a circular path of motion designated D in Fig. 6, but since the seat portion is, according to the invention, connected with the support via a coupling which in this case is mechanical and which positively and automatically effects a linear displacement of the seat portion as described above, as soon as the seat portion is swivelled about its shaft, the seat will describe a substantially elliptic path of motion E, when turned through 180°. This means that the space required in the lateral direction of the driver's cab is minimal, even if the seat portion in its posi- tions A,B is maximally moved back to a position in which there is plenty of space in front of the seat portion. Possible modifications of the invention

The invention is, of course, not restricted to the embodiment described above and shown in the drawings. Instead of the link 15 as shown, a roller or the like which replaces the hinge 14 can thus be used as a mechanical coupling, said roller running in a groove extending transversely of the centre line of the support. It is also conceivable to use couplings other than mechanical. Thus, the movements of the seat can be provided electrically, pneumatically and/or hydraulically, It should also be pointed out that the second guide means 12,13 for adjusting the seat portion to the size of the driver could per se be omitted, although this guide means is preferred in connection with seats for forest machinery or other machines. Should the second guide means be omitted, the eccentricity between the swivelling shaft of the seat portion and the support will, of course, be predetermined once and for all. In this context it should also be emphasised that the inventive idea is, of course, applicable not only to seats for vehicles or different types of machines, but also to chairs such as chairs to be used behind counters, hairdresser's chairs, office chairs etc.

Claims

1. A seat comprising a seat portion ( 1 ) carried by a stationary support (2), said seat portion swivel¬ ling about a shaft (10) which is preferably located centrally relative to said seat portion, and being connected with said support (2) via at least a first guide means (6) which allows displacement of the seat portion relative to said support, c h a r a c t e r ¬ i s e d in that the swivelling shaft (10) of said seat portion is positioned or settable eccentrically relative to the centre C" of said support (2), and that between the movable seat portion ( 1 ) and the stationary support (2) or parts thereof, there is mounted a preferably mechanical coupling (15) which positively and automatically effects the displacement of the seat portion relative to said guide means, as soon as the seat portion is caused to swivel about said shaft ( 10) .

2. The seat as claimed in claim 1, c h a r a c ¬ t e r i s e d in that a movable member included in said guide means (6) has the shape of a holder (8) carrying a swivelling mount (9) whose movable part constitutes or comprises the swivelling shaft (10) of said seat portion ( 1 ) , and that said coupling com¬ prises a pivot arm (11) which is nonrotatably connected with said swivelling shaft (10) and provided with a positively guided carrier means (14) which, when said arm is pivoted about the swivel centre or axis (C ) of the seat portion, causes said holder (8) to be moved along the fixed member (7) of said guide means.

3. The seat as claimed in claim 2, c h a r a c ¬ t e r i s e d in that said carrier means has the form of a hinge (14) of a link (15) having a second hinge (16) which is fixedly connected with said support (2) or a bracket (17) projecting from said support.

4. The seat as claimed in claim 2 or 3, c h a r ¬ a c t e r i s e d in that said pivot arm (11) consists of a second guide means (12,13) which allows variations of the eccentricity between the swivel axis (C) of the seat portion and the centre axis (C") of said support and, thus, adjustment of the seat portion in various positions adapted to the bodily constitution of different individuals, particularly the length of the legs.