GB1593500A

GB1593500A - Industrial lift truck

Info

Publication number: GB1593500A
Application number: GB1332477A
Authority: GB
Original assignee: NARROW AISLE UK Ltd
Current assignee: NARROW AISLE UK Ltd
Priority date: 1977-03-30
Filing date: 1977-03-30
Publication date: 1981-07-15
Also published as: FR2385639B1; JPS53121361A; FR2385639A1

Description

(54) INDUSTRIAL LIFT TRUCK (71) We, NARROW AISLE (U.K.) LIMITED, a British Company of Union Street, Bilston, West Midlands, WV14 OQT, do hereby declare the invention for which we pray that a Patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to an industrial lift truck of the kind having a load lifting device which can be arranged to deal with loads at one side or at both sides of the truck, as well as with loads in front of the truck.

A lift truck is often required to operate in narrow aisles to remove goods from racks at opposite sides of the aisle. In aisles having a width which is too small to allow a truck to turn, the use of a truck of the kind referred to above is essential. However, when such a truck carries a sideways load, the load may, with a truck with a conventional wheelbase arrangement, fall outside the wheelbase, making the truck unstable and tending to overturn it in a sideways direction.

Attempts to overcome this problem of stability have included making the truck exceptionally heavy, relative to the load it is intended to deal with, and extending the number of wheels from three to four and making the wheelbase extend beyond the position of the load carrying device when it is arranged for sideways loading.

However, it is clearly a disadvantage to make the truck very heavy, and a disadvantage of so extending the wheelbase is that the load lifting device cannot, in the sideways direction, pick up loads from ground level, since the chassis incorporating the extended wheelbase obstructs it.

An object of the present invention is to provide an industrial lift truck of the kind specified which can pick up a load, at at least one side thereof, from ground level.

According to the invention there is provided an industrial lift truck comprising a wheeled chassis, the chassis having a superstructure including drive means for propelling the truck, and a mast, said mast being at all times within the confines of the chassis, an arm movable up and down relative to the mast, the arm extending over the chassis and beyond a front end thereof, a load lifting device pivotally mounted on the arm at a position beyond the front end of the chassis, so that at all times it can be directed, in use, to either side of the truck or to the front thereof, the load lifting device, when directed sidewardly of the truck being disposed beyond said front end of the chassis so as to allow it to descend, in use, to a level of the surface on which the truck travels to pick-up a load from said surface.

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 an industrial lift truck constructed in accordance with the invention; Figure 2 is a front view of the truck, and Figure 3 is a plan view thereof.

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

Two adjacent corners at the rear of the vehicle are provided with wheels in the form of castors 11 whereas the other two corners are provided with pairs of fixed axle wheels 12. Under the rear of the chassis is a further larger drive and steering wheel 13. This is disposed midway between the sides of the chassis and is swivelable about a vertical axis by means of steer ing gear controlled by a hand wheel 14 and is also sprung to maintain contact with the surface over which the truck travels. The four corners of the chassis carry resilient cushions 15 for co-operation, in use, with guiding means for steering the truck down narrow aisles.

The chassis has secured to at its rear end a superstructure 16 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 17 and control levers of which one is indicated at 18. The superstructure also carries a seat 19 for an operator who sits facing sideways on the vehicle. A canopy 20 is provided over the operator area to protect him from objects which may fall from racks being served by the truck.

Also secured to the chassis 10 is a mast indicated at 21. This is of conventional kind and includes a lift mechanism controllable by the operator.

Carried on the lift mechanism of the mast 21 is a transversely disposed slide assembly comprising two spaced inter-connected parallel horizontal rails, 22, 23. The connection 24 between these rails is in the centre and corresponds in width generally to the width of the mast 21. The ends of the rails, therefore, extend in unsupported manner to the respective sides of the truck.

Carried by the two rails 22, 23 is an arm 25 which extends forwardly over the chassis and beyond a front end thereof. The rails 22, 23 are positioned near the front of the chassis 10 so that the arm 25 extends beyond the front end of the chassis which is a low platform in this region. The arm 25 carries guide means 26 for maintaining its position in relation to the rails but permitting lateral sliding movement of the arm across the front of the truck. Power operated control means are provided for producing the sliding movement, such control means being not illustrated but being carried by the superstructure 16. The guide means 26 are such that when the arm 25 occupies a position close to one end of the rails 22, 23 the arm will serve to stiffen the rail ends and prevent distortion under load.

It may, however, be necessary to provide additional stiffening for the rail ends, but such stiffening should be minimised in order that the operator can have a good view of the operating parts of the truck.

Pivotally carried on the outer end of the arm 25 is a load lifting device in the form of a fork assembly comprising a pair of flat forks 27, 28 connected by a member 29. The member 29 is pivoted about a vertical axis at the end of the arm 25 and rigidly supports the two forks 27, 28. The arm contains a mechanism for swivelling the forks about the axis. The forks are shown extending transversely of the truck but they can swivel through 1800 from the position shown. As can be seen from the figures, the forks, in their sidewardly extending position, are disposed beyond said front end 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 forks as shown within the width of the truck. The mast raises the forks together with the arm 25 and the rails 22, 23 to a level at which the forks 27, 28 coincide with the bottom of the load to be collected. The arm is now moved transversely of the truck so that the forks enter a space provided beneath the load. Further raising of the forks with the arm and the rails lifts the load so that it is wholly supported by the truck. It can then be brought out of the shelf by returning the arm to the initial position shown.The load may be swivelled to the front or to the other side of the truck by swinging the forks 27, 28 about the axis on the outer end of the arm 25 and the arm is traversed laterally of the truck along the rails to the appropriate position.

It is possible with this arrangement to pick up a load from floor level since the forks 27, 28 may be lowered below the level of the chassis 10 as illustrated in Figures 1 and 2.

When carrying a load at any position forwardly or laterally the truck is stable even though it does not have a very heavy weight at the rear of the truck to counterbalance the load. The positioning of the superstructure at the rear end of the chassis and the positioning of the front wheels up to, but not under, the forks in their sidewardly directed position ensures the stability of the truck.

WHAT WE CLAIM IS: 1. An industrial lift truck comprising a wheeled chassis, the chassis having a superstructure including drive means for propelling the truck and a mast, said mast being at all times within the confines of the chassis, an arm movable up and down relative to the mast, the arm extending over the chassis and beyond a front end thereof, a load lifting device pivotally mounted on the arm at a position beyond the front end of the chassis, so that at all times it can be directed, in use, to either side of the truck or to the front thereof, the load lifting device, when directed sidewardly of the truck being disposed beyond said front end of the chassis so as to allow it to descend, in use, to a level of the surface on which the truck travels to pick-up a load from said surface.

2. A truck as claimed in claim 1 wherein a slide is carried by the mast and is movable up and down thereon, the slide extending transversely across the chassis, said arm being mounted on the slide for movement along it.

3. A truck as claimed in claim 1 wherein the slide comprises two spaced, inter-connected horizontal rails, the interconnection being at the centre of the rails and of a width substantially equal to the width of the mast.

4. A truck as claimed in claim 3 wherein said arm is carried by said two rails, and the arm itself carries guide means for maintaining it in position in relation to the rails but permitting lateral sliding of the arm across the front of the truck.

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

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Carried on the lift mechanism of the mast 21 is a transversely disposed slide assembly comprising two spaced inter-connected parallel horizontal rails, 22, 23. The connection 24 between these rails is in the centre and corresponds in width generally to the width of the mast 21. The ends of the rails, therefore, extend in unsupported manner to the respective sides of the truck. Carried by the two rails 22, 23 is an arm 25 which extends forwardly over the chassis and beyond a front end thereof. The rails 22, 23 are positioned near the front of the chassis 10 so that the arm 25 extends beyond the front end of the chassis which is a low platform in this region. The arm 25 carries guide means 26 for maintaining its position in relation to the rails but permitting lateral sliding movement of the arm across the front of the truck. Power operated control means are provided for producing the sliding movement, such control means being not illustrated but being carried by the superstructure 16. The guide means 26 are such that when the arm 25 occupies a position close to one end of the rails 22, 23 the arm will serve to stiffen the rail ends and prevent distortion under load. It may, however, be necessary to provide additional stiffening for the rail ends, but such stiffening should be minimised in order that the operator can have a good view of the operating parts of the truck. Pivotally carried on the outer end of the arm 25 is a load lifting device in the form of a fork assembly comprising a pair of flat forks 27, 28 connected by a member 29. The member 29 is pivoted about a vertical axis at the end of the arm 25 and rigidly supports the two forks 27, 28. The arm contains a mechanism for swivelling the forks about the axis. The forks are shown extending transversely of the truck but they can swivel through 1800 from the position shown. As can be seen from the figures, the forks, in their sidewardly extending position, are disposed beyond said front end 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 forks as shown within the width of the truck. The mast raises the forks together with the arm 25 and the rails 22, 23 to a level at which the forks 27, 28 coincide with the bottom of the load to be collected. The arm is now moved transversely of the truck so that the forks enter a space provided beneath the load. Further raising of the forks with the arm and the rails lifts the load so that it is wholly supported by the truck. It can then be brought out of the shelf by returning the arm to the initial position shown.The load may be swivelled to the front or to the other side of the truck by swinging the forks 27, 28 about the axis on the outer end of the arm 25 and the arm is traversed laterally of the truck along the rails to the appropriate position. It is possible with this arrangement to pick up a load from floor level since the forks 27, 28 may be lowered below the level of the chassis 10 as illustrated in Figures 1 and 2. When carrying a load at any position forwardly or laterally the truck is stable even though it does not have a very heavy weight at the rear of the truck to counterbalance the load. The positioning of the superstructure at the rear end of the chassis and the positioning of the front wheels up to, but not under, the forks in their sidewardly directed position ensures the stability of the truck. WHAT WE CLAIM IS:

1. An industrial lift truck comprising a wheeled chassis, the chassis having a superstructure including drive means for propelling the truck and a mast, said mast being at all times within the confines of the chassis, an arm movable up and down relative to the mast, the arm extending over the chassis and beyond a front end thereof, a load lifting device pivotally mounted on the arm at a position beyond the front end of the chassis, so that at all times it can be directed, in use, to either side of the truck or to the front thereof, the load lifting device, when directed sidewardly of the truck being disposed beyond said front end of the chassis so as to allow it to descend, in use, to a level of the surface on which the truck travels to pick-up a load from said surface.