GB2190063A - Pallet truck - Google Patents

Abstract

To reduce the requirement for physical strength in the control of braking, truck handle (40) is provided with brake actuation means in the form of a twist grip (50). The arrangement is also failsafe in that the brake is normally applied, and is only taken off (i.e. released) when the grip (50) is turned from its rest position by an operator. Subsequent release of the grip (50) by the operator automatically results in re-application of the brake. <IMAGE>

Description

SPECIFICATION Pallet truck This invention concerns hand-operated pallettrucks.

Such trucks conventionally comprise a pair of tines which have support rollers at one end and are joined together at the other end by a steering head in which a stub of a steering wheel castor is journalled. A handle, by means of which the truck may be moved, manipulated and steered, is connected to the steering wheel castor, and the tines, which constitute a load-supporting body, may be raised and lowered relative to the castor re spectively for lifting a load and for depositing the load on the ground and withdrawing from therebeneath, so asto be available for insertion beneath another load, e.g. on a pallet.The steering wheel castor includes one or a pair of wheels, and it is usual to provide, at least on one ofthe wheels, a brake (such as an internal expanding drum brake) which can be applied by pivoting or "squeezing" a brake lever provided on a hand grip of the handle. The brake permits the truck to be controlled when being moved over inclined surfaces, such as ramps, especiallywhen loaded.

In supermarkets and like environments, it is standard practice for pallet trucks, both loaded and unloaded, to be handled by female labour, and ex perienceshowsthatthe conventional brake arrangement is not at all satisfactory since operatives with small hands are often notabletoapply sufficient squeezing pressure to the brake leverto maintain an adequate braking action. As a result, control ofthe truck can be lost and the truck may roll away under gravity with substantial risk of accident and injury to anyone in its path.

An object of the present invention is to obviate or minimise the above-mentioned difficulty by providing,fora pallettruck,a brakearrangement which can be operated using comparatively less power, so thatthetruckcan be handled readily and without risk by operatives without major dependence upon physical strength.

With this object in view the present invention provides a pallettruck having a steering wheel castor which includes at leastonewheel fitted with a brake and to which is connected a handle by means of which the truck may be moved, manipulated and steered, characterised in that actuating means for the brake comprises a twist grip on the handle,turning of which from a rest position takes the brake off, and release ofwhich results in application of the brake.

Accordingly, with the arrangement of the invention, the brake is normally "on", so that when no operative is present in charge ofthetruck, and its handle is not held bythetwistgrip with the latterturned, the truck is held stationary by the brake.

Preferably the twist grip is of a configuration permitting itto be gripped bytwo handssothat pulling-offofthe brake and controlling ofthe movement of the truck by means of the brake can be effected by means of either one or both of the operator's hands.

In a preferred practical embodiment a linkage is provided between the twist grip and a pivoted leverto cause the latterto be swung about its pivot, upon turning of the twist grip, the lever being coupled to transmission means connecting with the brake,soasto provide a substantiai mechanical advantage. The transmission means may conveniently comprise a Bowden cable.

The invention will be described further, byway of example, with reference to the accompanying drawings, in which Figure lisa perspective view iilustrating a preferred embodiment of the pallet truck ofthe invention; Figure2 is an enlarged fragmentary detail of the upper part of the handle of the truck of Figure 1 viewed from the opposite direction to Figure 1; and Figure 3 is an enlarged sectional elevation taken on the line 3-3 of Figure 2.

The illustrated preferred embodiment ofthe pallet truck ofthe invention comprises a body, indicated generally by the reference numeral 10, which includes a parallel pair oftines 12, 14 each having adjacent to its free end a respective roller 16 which can be lowered and raised through a small distance relative to theirtines, as will be referred to again later. These rollers 16 are shown in Figure 1 in their raised positions.

At their other ends, the tines 12, 14 are connected by a steering head 18 which is approximately of inverted V-shaped configuration from the apex of which projects a bracket 20 providing a mounting fora downwardly-projecting vertical stub (not visible in Figure 1) on which is disposed a sleeve-like bearing body 22 of a steering wheel castor which is indicated generally by the reference numeral 24. The body 22 is capable ofturn- ing about the axis of the stub which axis corresponds to the axis of the body 22, and the latter, additionally, is capable of limited up and down movement on the stube.At its bottom end, the bearing body 22 is united with a transverse yoke 30 below which is mounted a pairofsteering wheels 26,26 provided on a common axle 28 which extends through a carrier block orthe like (not visible) connecting with, and projecting downwards from, the yoke 30.

At least one, and preferably both, of the wheels 26 is provided with a brake (not visible) com prising a brake drum enclosing internal expansible brake shoes acted upon byspringswhich normally load the shoes towards their expanded con ditionssothatthebrakewill normally be "on", pulling "off" of such brake by contraction ofthe shoes being possible by way of a Bowden cable 32 which is visible in Figure 2.

Formed integrally with the bearing body 22 ofthe steering wheel castor 24 is a cantilever bracket 34 having a pair of side cheeks 36 between which is pivoted, by a pivot 38, the lower end of shaft40 of a handle, indicated generally by reference numeral 42, by which the truck can be manoeuvred and moved about. Associated with the lower end of the shaft 40 is a fluid pump44 which is actuated by pivoting or swinging movement about the pivot 38 of the handle 42 and supplies fluid under pressure to a jacking cylinder (not visible) to cause lowering ofthe rollers 16 relative to their tines 12 and 14 (and thus slight raising ofthetines) and to cause corresponding downward movement ofthe body 22 on its stub (to achieve corresponding raising of the steering head 18).

Referring to Figures 2 and 3, a horizontal tubular bearing 46 is secured to the upper end ofthe handle shaft 40 and a rod member48extends through this bearing 46to provide two handgrips 50, one at each side ofthe bearing 46. A pair of flanges 52 arefixedtothe member48, one at each side ofthe shaft 40, and extending between these flanges 52 is a cylindrical segment-shaped joint piece 54which serves, by abutment by one edge againsttheshaft40 and by engagement by its other end against an abutment 56 projecting from the shaft 40, to limit the possible turning movement ofthe rod member48 in the bearing 46.

Dog-leg struts 58,60 fixed to the shaft 40 near to the upper end thereof provide, attheir upper ends, flat straps 62 to which the ends of the rod member48 are rotatably connected. The rod member 48 has, on its ends, respective end flanges 64,66.

As can be seen from Figure 2, a flat mounting plate 68 is welded to the strut 60 and pivoted to this, by means of pivot 70, is one end of a brakerelease lever72,the other end of which is connected, by an adjustabie link 74, to a lobe 76 projecting radiallyfrom and formed integrally with the end flange 64. The inner wire 78 of the Bowden cable 32 is connected to the lever 72 by a socket 80 which receives a nipple on the wire 78, while the outer cover 82 of the Bowden cable 32 terminates at an adjuster 84 which is attached to a lug 86 projecting from the plate 68 in aiignment with the socket 80.The inner wire 78 of the Bowden cable 32 is connected to the lever at a position relatively close to the pivot 70 so that a good mechanical advantage is obtained.

Atrigger88 projecting from the shaft 40 nearto one ofthe handgrips 50 permits releaseofthe pressure offluid supplied to the jacking cylinder, thereby permitting the body 10 of the truckto sink down to its lowermost position.

The mode of use of the paliettruckwill readily be understood from the foregoing description.

When the handle 42 is left as shown in the drawings, the brake or brakes ofthe wheels 26 will be in the "on" condition, so that the truck will not move, even if it is resting on an uneven or sloping surface or if it is pushed. An operator can, however, manipulate the truck by means of the handle 42,providedthatwhen it is desired actuallyto move the truck, the or each brake is released by rotating the twist grips 50 from their normal illustrated positions. This can be done at the same time as the handle 42 is swung down from its illustrated upright position to a convenient position for manipulation.

The aforesaid rotation ofthetwistgrips 50 (which may be effected using one hand only if desired or appropriate) causes pivotal swinging of the lever72 (by way of theflange lobe76and the link 74) so as to draw on the innerwire 78 ofthe Bowden cable 32 and thereby move the brake(s) to "off" (i.e. release the brake(s)). Thetruck can now be manipulated and moved about in the normal way. The brake(s) will, however, be reapplied automaticallywheneverthe operator lets go ofthetwistgrip 50, andtherebyallowsthe lever 72 to reassume its initial position.

The brake(s) will have to be taken "off" (released) in the mannerjust described wheneverthe tines 12,14 have to be introduced beneath a load, such as a pallet (not shown) which is to be moved about. Then when this has been achieved, the twistgrips 50 may be permitted to return to their non-rotated positions so that the brake(s) come on again. With the brake(s) thus re-applied, the handle 42 may be swung about its pivot 38to pump fluid to the jacking cylinder and raise the pallet from the floor. Once this has been achieved, the twistgrip 50 can be rotated once again so thetruckcan be moved about as desired, until itis stopped again by release ofthetwistgrips again bringing about application ofthe brake(s).

Practical experiments show that the truck as described is particularly easy to control and manipulate, and the risk of accident and/or running away of the truck, especialiy when loaded, is completely eliminated.

Claims (5)

1. A pallet truck having a steering wheel castor which includes at least one wheel fitted with a brake and to which is connected a handle by means of which the truck may be moved, manipulated and steered, characterised in that actuating meansforthe brake comprises a twist grip on the handle,turning ofwhich from a rest position takes the brake off, and release of which results in application ofthe brake.

2. A pallet truck as claimed in claim 1 wherein the twist grip is of a configuration permitting it to be gripped bytwo hands so that pulling-offofthe brake and controlling of the movement ofthe truck by means ofthe brake can be effected by means of either one or both of an operator's hands.

3. Apallettruckasclaimedinclaiml or2wherein a linkage is provided between the twist grip and a pivoted lever to cause the latter to be swung about its pivot, upon turning of the twist grip, the lever being coupled to transmission means connecting with the brake, so as to provide a substantial mechanical advantage.

4. A pallettruckas claimed in claim 1,2 or3 wherein rotation ofthetwistgrip relative to the handle is limited by provision of a part-cylindrical abutment piece on the twist grip.

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