Lift truck accessory

Abstract

An industrial lift truck with a tilt measuring accessory, which provides an operator with a visual indication of the mast assembly tilt angle by means of a flexible cable operated sliding weight indicator mounted on the mast assembly. The flexible cable is fixedly mounted by a mounting device to a roll-cage and extends parallel, or substantially so, to the surface on which the lift truck is operating, before passing over a pulley mounted on the mast assembly to extend downwardly and parallel, or substantially so, to the mast assembly. The sliding weight is received for sliding engagement within a guide, wherein, when the mast assembly is tilted, movement of the flexible cable causes a corresponding movement of the weight relative to the guide thereby giving the visual indication of the angle of tilt of the mast assembly.

Claims

1. An industrial lift truck comprising a body housing for an operator, controls, means of propulsion and a mast assembly having forks, or other lifting attachments, which are movable up and down the mast assembly, the mast assembly mounted on the lift truck so that, in use, the mast assembly is pivoted relative to the body housing whereby an angle of the forks or other lifting attachments is changed by adjusting a tilt angle of the mast assembly, wherein the lift truck also comprises a tilt measuring accessory for providing, in use, a visual indication of the mast tilt angle, wherein the tilt measuring accessory is mounted between the body housing and the mast assembly, and wherein the tilt measuring accessory comprises: a flexible cable connected to a mounting device between the body housing and the mast assembly; and a pulley; the flexible cable extending, in use, substantially parallel to a surface on which the lift truck is operating, and after passing over the pulley the flexible cable extends downwardly substantially parallel with the mast assembly to provide support for a weight at a lower end of the flexible cable, the weight being located for sliding movement within a guide of the tilt measuring assembly.

2. The industrial lift truck according to claim 1, wherein the mounting device is fixed to a roll-cage of the body housing, and the pulley is secured to the mast assembly.

3. The industrial lift truck according to claim 1, where, when the lift truck is in use and the mast assembly is tilted, a relative distance between the mounting device and the pulley changes.

4. The industrial lift truck according to claim 3, where, when the lift truck is in use and the mast assembly is tilted backwards the distance between the mounting device and the pulley decreases.

5. The industrial lift truck according to claim 2, where, when the lift truck is in use and the mast assembly is tilted forwardly, the distance between the mounting device and the pulley increases.

6. The industrial lift truck according to claim 3, wherein movement of the flexible cable as the mast assembly is tilted causes a corresponding movement of the weight relative to the guide to provide a visual indication to an operator of the lift truck according to the tilt angle of tilt of the mast assembly.

7. The industrial lift truck according to claim 6, wherein the guide and/or the weight are provided with lines or colored bands, which, in use, provide a further visual indication to the operator of the tilt angle of the mast assembly.

8. The industrial lift truck according to claim 1, wherein the mounting device is fixed to the mast assembly and the pulley and the guide are mounted on a roll-cage of the body housing.

9. The industrial lift truck according to claim 1, wherein a position of the weight is viewable within the guide.

10. An industrial lift truck tilt measuring accessory, comprising: a flexible cable connected, in use, to a mounting device between a body housing and a mast assembly of an industrial lift truck; and a pulley; the flexible cable extending between the pulley and the mounting device, in use, substantially parallel to a surface on which the lift truck operates in use, and after passing over the pulley the flexible cable extends downwardly substantially parallel with the mast assembly to provide support for a weight at a lower end of the flexible cable, the weight being located for sliding movement within a guide of the tilt measuring assembly.

11. The industrial lift truck measuring accessory according to claim 10, wherein a position of the weight is viewable within the guide.

12. The industrial lift truck measuring accessory according to claim 10, wherein movement of the flexible cable as the mast assembly is tilted causes a corresponding movement of the weight relative to the guide to provide a visual indication to an operator of the industrial lift truck according to the tilt angle of the mast assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An example of the invention will now be described by referring to the accompanying drawings:

(2) FIG. 1 shows a typical forklift truck as an example of an industrial lift truck, and identifies its main parts.

(3) FIG. 2 shows how the mast and forks can move relative to the truck body.

(4) FIG. 3 shows the mast tilt angle indicator according to an embodiment of this invention.

(5) FIG. 4 shows the mast tilt angle indicator according to a further embodiment of the invention.

DETAILED DESCRIPTION

(6) An embodiment of the present invention, see FIG. 3, comprises a lift truck 1 provided with a flexible cable 9 connected to a roll-cage 3 of the lift truck 1 by a mounting device 10. The cable 9 runs from the mounting device 10 in an approximately horizontal direction to a pulley 8, which is affixed to the lower section of a mast 4 of the lift truck 1. Thus, components of the tilt measuring accessory are mounted between the body housing and the mast assembly.

(7) The cable 9 changes direction in the pulley 8 to run parallel to and down the mast 4. The end of the cable 9 is fixed to a weight 7. The weight 7 is restrained by, but free to slide within, a guide 6, which is fixed to and orientated vertically on the mast 4. The guide 6 is mounted approximately at eyelevel of the operator 2. The weight 7 keeps the cable 9 under constant tension.

(8) In the illustrated example, the weight 7 is cylindrical, and is constrained concentrically within guide 6 which is tubular. The weight 7 is equal length or longer than guide 6. The weight 7 and guide 6 are mounted such that, with the forks 5 in a level position relative to the surface 0 on which the lift truck 1 is operating, the weight 7 is symmetrically within the guide 6.

(9) During operation of the lift truck 1 and as the mast 4 is tilted, the relative distance between the mounting device 10 and the pulley 8 will change. If the mast 4 is tilted back, then the distance between the mounting device 10 and the pulley 8 will decrease. Conversely, if the mast 4 is tilted forward, then the distance between the mounting device 10 and the pulley 8 will increase.

(10) Since the cable 9 has a fixed length, any change in tilt of mast 4 will result in weight 7, being acted on by gravity and cable tension, sliding within guide 6. The relative position of weight 7 within guide 6 therefore gives a visual indication to the operator 2 of the tilt angle of the mast 4 and forks 5 of the lift truck 1 relative to the surface 0 on which the lift truck 1 is working, see FIG. 3.

(11) Backward tilt of the mast 4 will result in (the bottom end of) the weight 7 appearing partially below the bottom end of the guide 6 and, conversely, a forward tilt of the mast 4 will result in (the top end of) the weight 7 appearing partially above the top end of the guide 6.

(12) Thus, it will be appreciated that the mast 4 is at a right angle to the surface 0 on which the lift truck 1 is working when the weight 7 appears to be centralised within the guide 6.

(13) Other embodiments of the lift truck 1 accessory are envisaged within the scope of the Claims appended hereto.

(14) For example, the function of the pulley 8 may be provided by a sheave, elbow or eyelet.

(15) Also, the flexible cable 9 may be mounted on the lift truck by means for allowing the length of the cable 6 to be adjusted, thereby providing a means to calibrate the indicator.

(16) The guide 6 and the weight 7 may be usefully provided with lines, coloured bands, or other markings, which indicate to a lift truck operator the degree of angle of tilt of the mast 4.

(17) The guide 6 and weight 7 may engage by other sliding means, for instance pegs and slots.

(18) The weight 7 may be shorter than the guide 6, with other means of determining their relative positions, for instance, the guide 6 may incorporate a window, or be transparent, so that the position of the weight 7 can be viewed within.

(19) The guide 6 and pulley 8 functions could be incorporated into one component, for instance a tube with 90 bend.

(20) In an alternative arrangement of the invention, see FIG. 4, the cable mounting device is fixed on the mast 4 and a pulley 8 and guide 6 are mounted on the lift truck body.