GB2279934A

GB2279934A - A device for transporting a load

Info

Publication number: GB2279934A
Application number: GB9314862A
Authority: GB
Inventors: Michael Donnelly Fage
Original assignee: Eurotech International Ltd
Current assignee: Eurotech International Ltd
Priority date: 1993-07-17
Filing date: 1993-07-17
Publication date: 1995-01-18
Anticipated expiration: 2013-07-17
Also published as: GB2279934B; GB9314862D0

Abstract

A device for transporting a load including: a base (12> a drive means (18) mounted on the base; a steerable wheel (14) mounted for rotation on a first end portion of the base, the steerable wheel being drivable by the drive means; a pair of wheels (16) mounted for rotation on a second end portion of the base; a lifting means (30), mounted generally at the first end portion of the base, comprising a coupling (40) which is movable in a generally vertical plane and is adapted to engage and bear the load, the device being constructed such that in use when the coupling is bearing the load, the pair of wheels are lifted from the ground. <IMAGE>

Description

A DEVICE FOR TRANSPORTING A LOAD The present invention relates to a device for transporting a load, particularly in an industrial setting.

Often in industry, forklift trucks are used to transport heavy loads from one location to another. However, it is known that the upper size limit of loads with which a forklift truck can cope is relatively low; for example, about 2 tons for average size trucks.

When loads of greater weight need to be transported, an industrial traction-engine or tractor is used. The problem with the traditional tractor is that it must be of sufficient weight for its drive wheels to gain adhesion with the surface to move a given load; it also requires a draw bar, or chains or the like to attach it to its load.

The large weight requirement invariably leads to a tractor of increased dimensions and together with the need for a draw bar results in a train of large overall length. These factors increase the turning circle of the train and thus reduce its manoeuvrability. In addition, the large weight of the tractor also requires an appropriate power supply with which to move both the payload and the tractor; the large weight of the tractor is undesirable in this regard.

With the above problems in mind, it is an object of the present invention to provide a device capable of transporting relatively heavy loads, but yet retains a high degree of manoeuvrability.

To this end, the present invention provides a device as defined in the claims.

Exemplary embodiments of the invention are herein described with reference to the accompanying drawings, in which: Figure 1 shows a side view of a device in accordance with the present invention being manoeuvred into engagement with a load; and Figure 2 shows the device of Figure 1 in engagement with the load.

The device for transporting a load from one location to another is generally designated 10 and is hereafter referred to as a tractor. The tractor 10 comprises a wheel base 12 to which three wheels are mounted for rotation. A large wheel 14 is disposed at a first, forward end of the base 12 and a pair of smaller, stabilising wheels 16, only one of which is visible in the drawings, are disposed at a second, rearward end of the base 12. The tractor 10 also comprises a driving means 18 which is operable under the control of an operator to drive the large wheel 14 via gear means which is not shown.

The driving means 18 can be in the form of an internal combustion engine or an electrical drive.

The control of the tractor 10 by an operator is effected by a control means 20 which is operable to permit the operator to control the drive means 18 and move the drive wheel 14 about so as to steer the tractor 10.

In the illustrated embodiment, the control means 20 includes an elongate member 22 which if moved left or right i.e. out of or into the plane of Figures 1 and 2, causes the drive wheel 14 to move left or right, respectively. The control means 20 also includes control buttons 24 which serve to activate the drive means 18. The control button 24 can be similar to those described in more detail in the applicant's patent GB-B-2229150.

For example, one of the control buttons 24 may activate the drive means 18 while the other may activate a brake (not shown).

The tractor 10 further comprises a lifting means in the form of a manually-operated screw-jack 30, which is disposed generally at the first end portion of the base 12. The jack 30 comprises an upstanding member 32, which is disposed above the axle of the drive wheel 14 and along which a coupling 40 can travel on rotation of a handle 34. The coupling comprises a generally 'L'-shaped portion, one limb 42a of which is horizontal and attached to the member 32, the other limb 42b being vertical and having a 'U'-shaped portion 44 at its end remote from the limb 42a. As is apparent from the drawings, the length of the horizontal limb 42a is sufficient for the vertical limb 42b to be spaced from the front, first end of the base 12. The 'U'-shaped portion 44 of the coupling 40 serves to engage the load, in this example a wheeled trailer designated 100, which is to be transported.

It will be appreciated that in a given instance the geometry of the coupling 40, and more particularly the 'U'-shaped portion 44 thereof, can be varied to match the characteristics of the trailer 100 and the part of the trailer to which it is to be engaged.

In use, the tractor 10 is manoeuvred by an operator using the control means 20 into the position illustrated in Figure 1. In this position, it is noted that the 'U'-shaped portion 44 of the coupling 40 is immediately below the portion 102 of the trailer 100 to which is to be engaged and all the wheels 14,16 of the tractor 10 are in contact with the ground. Next, the coupling 40 is raised, by rotation of the handle 34, into engagement with the trailer 100 in particular a suitable portion 102 of the trailer 100.

As the handle 34 is further rotated the coupling 40 begins to bear the weight of the trailer 100. Once this is accomplished to a sufficient extent, due to the construction of the tractor 10, the tractor 10 pivots about the drive wheel 14 until it reaches the position illustrated in Figure 2. It will be appreciated that the pivotal movement of the tractor 10 is facilitated by (i) the size difference between the wheels 14,16 which gives the tractor 10 a backward tilt in the the Figure 1 position, and (ii) the slight resilience in the 'L'- shaped portion of the coupling 40. The resilence of the coupling 40 also serves to provide promote tight engagement with the portion 102 of the trailer 100.

In this Figure 2 position, it is noted that the smaller pair of wheels 16 are lifted from the ground, leaving the drive wheel 14 as the sole load-bearing and ground-engaging wheel. The handle 34 of the jack 30 is then further rotated until enough weight has been transferred from the trailer 100 to the tractor 10, more particularly the drive wheel 14, to provide sufficient adhesion to move the trailer 100. Once this is accomplished, the operator using the control means 20 can then transport the trailer 100 to another location.

To disengage the trailer 100 from the tractor 10, the coupling 40 is simply lowered using the handle 34 so that the tractor 10 returns to its Figure 1 position.

Since the jack 30 pivots and is situated over the drive wheel 14, it is possible to turn the tractor 10 through 90" making the tractor 10 very manoeuvrable.

It has been found that a tractor as described above using an electric motor can readily transport on a flat surface a 6 ton load using a 12 volt power supply and a 16 ton load using a 24 volt power supply. It will be appreciated that the gear means is selected to provide the required torque to move the load, and the power output of the drive means 18 is selected to enable the tractor 10 to travel at the required speed.

The required speed for the tractor when transporting a load is usually very low. Accordingly, it is a feature of the tractor that when it is not transporting a load, it can be pivoted onto its small wheels and pushed by an operator at a relatively high speed on its undriven wheels 16.

Claims

1. A device for transporting a load including: a base; a drive means mounted on the base; a wheel mounted for rotation on a first end portion of the base, the steerable wheel being drivable by the drive means; a pair of wheels mounted for rotation on a second end portion of the base; a lifting means, mounted generally at the first end portion of the base, comprising a coupling which is moveable in a generally vertical plane and is adapted to engage and bear the load, the device being constructed such that in use when the coupling is bearing the load, the pair of wheels are lifted from the ground.

2. The device as in claim 1 and further comprising a control means which is operable to permit an operator to control the drive means and direct the tractor.

3. The device as in claims 1 or 2, wherein the wheel is larger than the pair of wheels.

4 The device constructed, arranged and adapted to operate substantially as herein described with reference to the accompanying drawings.