GB2042470A

GB2042470A - Lift trucks

Info

Publication number: GB2042470A
Application number: GB7943605A
Authority: GB
Original assignee: NARROW AISLE Ltd
Current assignee: NARROW AISLE Ltd
Priority date: 1979-02-23
Filing date: 1979-12-18
Publication date: 1980-09-24
Also published as: GB2042470B

Abstract

A lift truck comprising a chassis (10), a superstructure (16) on the chassis, a mast (19) movable transversely across and over the chassis (10), an arm (25) carried by the mast for vertical movement thereon, the arm extending over and beyond a front end of the chassis, and a load receiving device (26, 27, 28) pivotally mounted on the arm (25) at a position beyond said front end of the chassis, so that it can descend to the level of the surface over which the truck travels, to pick up a load therefrom. The traverse of the mast enables the operator to have an improved view of the load receiving device, particularly as the mast is disposed with its front facing in the direction of its transverse movement. <IMAGE>

Description

SPECIFICATION Lift trucks This invention relates to lift trucks, in particular to lift trucks intended for narrow aisle operation.

It is obviously desirable with lift trucks intended for use in narrow aisles, that the truck can collect loads from either side of the aisle and can also raise or lower loads so collected. Moreover it is advantageous if the truck can pick up loads from ground level.

Various constructions of lift trucks exist for carrying out these operations. For example in U.K. Patent Specification No. 1, 423, 144 there is shown a lift truck in which a traversing carriage is disposed at the front of the truck body, the carriage having upper and lower horizontal members extending outwardly therefrom pivotally to mount a movable mast which carries a pair of forks which can be raised or lowered on the mast. The forks can pick a load up from the level of the surface over which the truck travels.

To pick up loads in the manner described, the movable mast is positioned some way away from the front of the main body of the truck and in order to overcome any stability problems arising from such positioning of the mast, the truck is often made relatively long and/or a heavy counterweight is provided at the rear of the truck.

In our co-pending U.K. Patent Application No. 13324/77 there is described and shown a lift truck which has the facility to pick up a load from the level of the surface over which the truck travels. The truck overcomes the problem of its stability, however, by arranging for the forks to be mounted at the end of an arm which extends over and beyond a front of the chassis of the truck from a slide which can be raised or lowered on a mast spaced from said front of the chassis. The arm itself is movable transversely across the slide.

Such a truck has the disadvantage, however, that the mast tends to obscure the operator's view of the forks, particularly if the mast is provided with strengthening means such as braces and the like.

Accordingly the object of the present invention is to provide in a convenient manner a lift truck which allows an operator of the truck an improved view of a load receiving device of the truck, in use.

According to the invention of lift truck comprises a chasis, a superstructure on the chassis, a mast movable transversely across the truck in a permanently fixed disposition thereon, and load receiving means which move up and down with said member.

The invention will now be described, by way of example with reference to the accompanying drawings, in which: Figure 1 is a side view of a lift truck of the invention and: Figure 2 is a plan view thereof.

The truck illustrated comprises a rigid structural chassis of generally rectangular configuration and indicated at 10 in the drawing.

Two adjacent corners at the rear of the truck are provided with wheels in the form of castors 11, whereas the other two corners are provided with pairs of fixed axle, load wheels 1 2. The castors 11 can be replaced by a pair of wheels which allow movement downwards from and upwards to a predetermined level, but which prevent movement of the wheels above said predetermined level.

Under the rear of the chassis is a further, larger drive and steering wheel 1 3. This is disposed midway between the sides of the chassis and is swivelable about a vertical axis by means of steering gear controlled by a handle 1 4 and is also sprung to maintain contact with the surface over which the truck travels. The four corners of the chassis carry resilient cushions 1 5 for co-operation in use, with guiding means for steering the truck down narrow aisles.

The chassis has secured to it at its rear end, a superstructure 1 6 containing a power source and control apparatus for controlling the various functions of the truck. Mounted on top of the superstructure is a steering column and control levers, of which one is indicated at 1 7. The superstructure also carries a seat, not shown, for an operator who sits facing sideways of the truck. A canopy 1 8 of the superstructure is provided over the operator area to protect him from objects which may fall from racks being served by the truck.

A dual-section, rectangular mast 1 9 is disposed at the front of the truck for movement transversely thereacross. The mast 1 9 is disposed 'side-on', that is with its open front facing in the direction of transverse movement of the mast. The front end of the chassis 10 is a low platform and the mast extends across this platform to the end thereof so that at the ends of its traversing, it is within the confines of the chassis. The front end of the chassis is slightly cut away between said two end positions of the mast, but the substantial majority of the mast is still within the area of chassis even when its end is over said cut away portion.

The mast 1 9 comprises an outer section, in the form of spaced vertical columns 20, 21, and an inner section 22 which is extensih- o within the outer section by way of a hydra~.ic lift cylinder 23 disposed centrally of the inner section. The inner section 22 can thus, in a conventional manner be raised and lowered relative to the outer section which thus acts as guide means for it.

The superstructure 1 6 and the outer section of the mast 1 9 have co-operating power operated traversing means 24 for moving the mast 1 9 transversely across the front of the truck.

The traversing means can be of any suitable conventional type, such as the rack and pinion means shown in Fig. 1. The mast may additionally be provided with means which cooperate with the superstructure to guide and stabilize the mast as it traverses. Mounted around the mast 1 9 is a forwardly extending arm 25 which can be raised or lowered on the inner section 22 of the mast 1 9. The cam 25 extends over and beyond the front end of the chassis 10 and has a load receiving device pivotally mounted thereon.

The load receiving device is in the form of a fork assembly comprising a pair of flat tines 26, 27 connected by a member 28. The member 28 is pivotable about a vertical axis at the end of the arm 25 and rigidly supports the two tines. The arm 25 contains a mechanism for swivelling the tines about the vertical axis. In Fig. 1 and in full Fig. 2, the tines are shown extending transversely of the truck but they can swivel through 180 as shown in chain-dotted lines in Fig. 2. As can be- seen, the tines in their sidewardly extending position, are disposed beyond said front end of the chassis. However they are disposed oniy a short distance from it and when raised in this position, a load then received by said tines may extend over the low platform part of the chassis.

In operation, the truck is designed principally for serving shelves spaced apart by a relatively narrow aisle. The aisle width may be only slightly wider than the total width of the truck. To collect a load from a shelf at one side of the aisle, the truck is positioned with the tines as shown within the width of the truck. The mast raises the arm and the tines to a level at which the tines coincide with the bottom of the load to be collected. The mast is now moved transversely across the truck so that the tines 26, 27 enter a space provided beneath the load. Further raising of the arm and tines lifts the load so that it is wholly supported by the truck. It can then be brought out of the shelf by returning the mast to the initial position shown.The load may be swivelled to the front of to the other side of the truck by swinging the tines about the axis on the outer end of the arm, and traversing the mast laterally of the truck by means of the mechanism 24 to the appropriate position.

It is possible with this arrangement to pick up a load from the floor level, since the tines may be lowered below the level of the chassis, as shown in Fig. 1. If the load to be received by the tines is at a level above the top of the inner mast section, it is necessary to raise the inner mast section, so that the load lifting device can reach the required height.

When carrying a load at any position forwardly or sidewardly, the truck is stable even though it does not have a very heavy weight at the rear of the truck to counter-balance the load. The positioning of the superstructure at the rear end of the chassis and the positioning of the front wheels upto, but not under, the tines in their sidewardly directed position assist the stability of the truck. However as compared to the truck of U.K. Specification No. 1423114, it is the positioning of the mast which is most important. With said specification, the mast is pivotally mounted on members extending out from the front of the truck. Thus the heavy mast is well away from the front of the truck as is also the load.With the truck of the invention the mast is much less far away from the superstructure and is, in the example illustrated, at the front of the truck and within the area of the chassis.

In an alternative arrangement, however, the mast and superstructure'have co-operating traversing means at the end of the chassis, so that the mast extends wholly beyond the chassis, with the arm 25 mounted on it in the same way as with the illustrated construction, this alternative arrangement is still more satisfactory than that of the prior art, in that the operator's view of the forks of the load lifting device is improved by virtue of the mast being traversible and also being disposed "side-on".

Although as described, the truck has a multi-section mast, a non-extensible mast could of course equaily well be used. Moreover the tines need not be arranged to pick up from the surface over which the truck moves, as described, although this is, of course, a very advantageous preferred arrangement.

Claims

1. A lift truck comprising a chassis, a superstructure on the chassis, a mast movable transversely across the truck in a permanently fixed disposition, a member carried by the mast for movement up and down thereon, and load receiving means which move up and down with said member.

2. A lift truck as claimed in claim 1, wherein said mast is disposed with its front facing in the direction of its transverse movement across the truck.

3. A lift truck as claimed in claim 1 or claim 2, wherein the mast and the superstructure have respective co-operating traversing means for moving said mast transversely across the truck.

4. A lift truck as claimed in any one of claims 1 to 3, wherein said traversing means are a rack and pinion.

5. A lift truck as claimed in any one of claims 1 to 4, wherein the mast is movable transversely across and over the chassis, said member extends over and beyond a front end of the chassis and said load receiving means is mounted in said member at a position beyond said front end of the chassis, so that it can descend in use, to the level of the surface over which the truck travels, to pick up a load from said surface.

6. A lift truck as claimed in any one of the preceding claims, in which said mast is telescopic, having an inner section which can be raised or lowered relative to an outer section, said member being moved up or down on said inner section.

7. A lift truck as claimed in any one of the preceding claims in which said load receiving means is a pair of tines pivotally arranged on said member, so that said means can be directed, in use, to either side of the truck or to the front thereof.

8. A lift truck substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

CLAIMS 24.4.80

1. A lift truck comprising a chassis, a superstructure on the chassis, a mast movable transversely across the truck in a permanently fixed disposition, an arm carried by the mast for movement up and down thereon and extending away from the mast in a direction parallel to a longitudinal axis of the truck, and load receiving means which move up and down with said arm.