VEHICLE SEATS AND SEAT SUPPORT LINKAGESThis invention relates to vehicle seats and seat support linkages. More particularly, but not exclusively, the invention relates to a driver's seat on an industrial truck, and a support linkage therefor. However, the invention is also applicable to other vehicle seats, and not necessarily driver's seats.
In an industrial truck the driver's seat is often fixed facing forwardly. In this case, when the vehicle is to be driven backwards the driver has difficulty viewing to the rear and operating the controls.
Sometimes, the driver will swivel in his seat or even stand up to reverse the truck. This can cause excessive tiredness or strain related problems. For example, for some trucks, particularly a truck operated in aisles, the driver may have to drive backwards nearly as often as forwards.
To try to overcome these difficulties, the seat may be carried on support means whereby the seat is rotatable within the driver's cab. However, the driver may then not be able to actuate the controls ergonomically. Alternatively, it is known to rotate the controls with the seat, but this can result in a complicated construction. In such an arrangement, the seat would follow a circular path determined by the location of the seat and the controls.
According to the invention there is provided a seat support linkage comprising a seat carrier mounted to move between a rest position and a turned position through a predetermined angle, wherein the seat carrier is mounted on a linkage adapted to move the seat carrier simultaneously forwardly or rearwardly and laterally in the same horizontal plane, during movement of the seat carrier from one of said positions to the other said position, along a noncircular path.
In one embodiment of the invention the linkage comprises three links pivotally connected end to end with the outer ends of the first and third links adapted to be pivotally mounted at fixed points, and the seat carrier is mounted on the linkage for movement in fixed relation with the second link.
Preferably the seat carrier is mounted on the pivot connection between the first and second links.
It is also preferred that, in the rest position of the seat carrier, the first and second links are substantially in line and the third link is folded relative to the second link. In this case the linkage is preferably adapted to move the seat carrier from the rest position to said turned position in which the first link of the linkage is folded relative to the second link, and the second and third links are substantially in line.
One or more of the links may be extendible to achieve an enhanced lateral and/or forward or rearward movement of the seat to at least one further turned position.
Preferably the seat carrier is movable between said positions by a person sitting on a seat mounted on the seat carrier applying pressure through the seat and the seat carrier to the linkage.
Alternatively, drive means may be provided for moving the seat carrier between said positions.
The invention also provides a vehicle seat comprising a seat mounted on the seat carrier of a seat support linkage as defined above.
Preferably the seat is a driver's seat of an industrial truck, for example, a man-up truck or a counterbalance truck, having controls actuated by the driver, the seat support linkage allowing said movement of the seat independently of the controls.
In one embodiment the truck has a body structure and a mast with the seat mounted in front of the mast, and the seat in its rest position is located within a recess defined by stationary elements of the driver's compartment.
By way of example, a specific embodiment in accordance with the invention will be described with reference to the accompanying drawings in which:Figure 1 is a perspective view of a man-up truck;Figure 2 is a plan view of the driver's seat of the truck of Figure 1, the seat being mounted on a seat support linkage for movement between a rest position and at least one turned position;Figure 3 is an elevation of the seat support linkage in its condition when the seat is in its rest position; andFigure 4 is a perspective view of the seat and the seat support linkage from one side of the truck, the seat having been moved into a turned position.
Figure 1 of the drawings shows an electrically driven industrial lift truck comprising a body portion 10, battery 11, and extendible mast structure 12.
Mounted on the mast structure is a driver's compartment 13, and turret load support means 14 including a secondary mast 15, load carriage 16 and load support forks 17. As in a conventional truck of this type, the driver rises with the load support means 14 and the turret enables the driver to pick up loads both forwardly of the truck or laterally, the turret moving to either side on racks 18 fixed on the front of the driver's compartment. Such a truck is known as a man-up truck and the above features are known and need not be described further.
Pivoted gates 47 allow access to the driver's compartment 13 from either side. Within the driver's compartment 13, control means, comprising a control panel 20 (Figure 4), are accessible to the driver to enable the driver to actuate drive means for manoeuvring the truck and for performing the particular functions of the truck. In this embodiment, each control operation is electronically actuated by a respective switch on the control panel. A separate knob activates an emergency brake. The multiplicity of switches on the control panel 20 are connected by electric cables to the respective drive means.
A seat 23 is provided for the driver which normally faces forwardly of the truck in the conventional manner for this type of truck, and is described as its rest position. In its rest position, (see Figure 2), the seat 23 is located within a recess 24 formed by the side uprights 19 and a transverse member 21 of the driver's compartment 13 all of which are stationary elements of the compartment. The driver can readily operate the controls when sitting on the seat, but can have difficulty viewing to the rear through glass panel 37 when reversing the truck. The driver may swivel in his seat or stand up in order to reverse the truck more readily. Accordingly, this difficulty can cause excessive tiredness or strain related problems. Moreover, when operating a man-up type truck within aisles, the driver may have to reverse the truck nearly as often as he drives it forwards.
The invention relates to easing this problem by allowing the driver to move the seat independently of the controls into at least one turned position, whereby he can view more easily to the rear and yet still operate the controls ergonomically. The movement of the seat may also assist the driver when he wishes to stand in order to move around the compartment, for example, for manually loading goods onto the forks 17.
Referring to Figure 2, the seat 23 has a mounting post 25 which is rigidly attached, e.g. by welding, to a seat carrier plate 26. The plate 26 is mounted on a linkage which allows the driver when sitting on the seat 23 in its rest position 27 to move the seat into either one or two turned positions 28, 29. In the first turned position 28, the seat 23 has moved simultaneously forwardly and laterally through a predetermined angle along a non-circular path. The seat 23 can thereby move out of the recess 24. In the second turned position 29, the seat 23 has moved through a greater angle, and is displaced further both forwardly and laterally, again along a non-circular path, but remains within the confines of the driver's compartment 13. For the return movement of the seat 23 to its rest position 27, the seat moves in reverse, both rearwardly and laterally simultaneously.Also, throughout these movements, it is intended that the seat should be supported and guided solely by the linkage. Alternatively, if desired, the seat could be designed to slide on the floor of the driver's compartment 13, or on a slide surface, for example, a rail which also guides the seat through its turning movements.
The linkage of this embodiment will be described in detail. The linkage comprises three basic links 30, 31, 32 pivotally connected end to end. The outer end of the first link 30 is mounted by hinge plate 38 on one of the uprights 19 of the driver's compartment 13, for pivotal movement about the vertical axis of block 34. Pivotally attached to respective ends of the block 34 are two strips 39 formed by a spacer member 40. The other ends of the strips 39 are pivotally attached to connector 35 on one end of the second link 31 and to which the seat carrier plate 26 is fixed. The first link 30 thus comprises a cantilever support for the seat which moves in an arc about the axis of block 34.
The second and third links 31, 32 respectively are pivotally connected at 36 and the outer end of the third link 32 is pivotally mounted by bracket 41 on the transverse member 21 of the driver's compartment.
The third link 32 is telescopic so that it is extendible. The links 31, 32 thereby comprise guide links as the seat moves successively between the predetermined positions. More specifically, in the rest position 27 of the seat 23, the first and second links 30, 31 are substantially in line with the third link 32 folded relative to the second link 31. As the seat moves towards its first turned position 28, the second and third links 31, 32 straighten and are substantially in line at the first turned position, whilst the first and second links 30, 31 become folded relative to each other. During movement of the seat 23 to its second turned position 29, the third link 32 becomes extended.During the return movements, the third link 32 is first contracted, followed by the second and third links 31, 32 becoming folded relative to each other as the seat moves between its first turned position 28 and its rest position 27.
It will be appreciated that, in this embodiment, the driver has the freedom of directly moving the seat 23, for example, as shown in Figure 4, to its chosen turned position, independently of the controls, in order to obtain a better rear view without altering his position on the seat and whilst still being able to operate the controls ergonomically. The controls, therefore remain fixed. The driver is also able to move the seat in order to give himself more standing room or more freedom for movement on the floor of the driver's compartment 13. On the other hand, location of the seat in the recess 24, when in its rest position 27, minimises the space required within the driver's compartment in order to allow the driver to gain access and to move around.
The invention is not restricted to the specific details of the embodiment described above. For example, detent means may be provided for locating the seat carrier plate 26 and thereby the seat 23 in its rest position 27 and/or one or both of the turned positions 28, 29. If desired, releasable locking means may be provided for the seat carrier plate 26, which means have to be released by the driver before he can move the seat 23 from one position to another position. Drive means may be provided for moving the linkage between predetermined positions, instead of the driver applying body force. If only one turned position is required, the third link 32 may be of fixed length rather than being extendible.
Alternatively or additionally, any one of the links may be extendible, depending on the number of predetermined turned positions required.
Furthermore, the seat support linkage may be used for the driver's seat on other trucks, for example, counterbalance trucks or reach trucks so that the seat may be orientated from its normal driving position to one or more other positions, particularly to assist the driver to reverse the truck. The linkage may also be useful in other vehicles and not necessarily for the driver's seat. For example, the linkage could be applied to a passenger seat.