GB2096571A - Masted lifting trucks with lifting chains - Google Patents

Abstract

In a load lifting truck with a mast 14, a load bearing unit 32 mounted on the mast for vertical movement, and cylinders 28 arranged to raise and lower a chain 38 via a sprocket 36, the load bearing unit includes or is adapted to include load handling means operable from a location spaced from the unit by control means. These control means include a flexible control line 44 which overlies the chain and which is attached thereto by fasteners 48 embracing respective link elements of the chain. <IMAGE>

Description

SPECIFICATION Load lifting trucks This invention concerns load lifting trucks and particularly trucks of the type with a mast on which a load bearing unit is mounted for vertical movement to raise and lower a load, the load bearing unit including or being adapted to include load handling means operable from a location spaced from the load bearing unit by control means including at least one flexible control line.

Conventionally, the load handling means in this type of truck may, for example, be a carriage known as a side shifter provided with load support arms or forks on which a load can be placed and fitted to a portion of the unit for movement laterally of the truck under the control of the control means. Alternatively, the load handling means may comprise a device known as a rotator also having load support arms or forks for supporting the load from below but in this instance being adapted to be rotated by the control means. Another possibility is for the load handling means to be one of a variety clamping arrangements capable of clampingly supporting a load and at the same time rotating it or shifting it laterally of the truck.In general, these load handling means are attachments fitted to a vertically movable carriage portion of the load bearing unit, and are designed for fitting to a truck as and when desired.

In one truck of this type the mast comprises a pair of upright members providing tracks along which the load bearing unit is movable. A cylinder is disposed between the upright members to effect movement of the load bearing unit through a chain and sprocket linkage, the sprocket being movable parallel to the upright members by actuation of the cylinder, and the chain, which is guided over the sprocket, being connected at a first end to the load bearing unit and at a second end being fixed relative to the truck body.ln order to guide the flexible control line from the load bearing unit to the truck body, a pulley is provided adjacent to the sprocket in a space between this sprocket and one of the two upright members.This arrangement of the control line between the upright members to a certain extent shields it from accidental damage but has the disadvantage of obscuring regions of the truck drivers's field of vision.

It has been suggested, to improve the visibility from the truck, that a guide for the control line be riveted to the chain itself so that the control line can overlie the chain rather than being positioned beside it but in this case a suitable chain which is capable of accepting the rivets is manufactured specifically for the particular truck.

The present invention provides a load lifting truck having a mast, a load bearing unit mounted on the mast for vertical movement, an actuator for effecting movement of the load bearing unit, the actuator being arranged to raise and lower, in relation to a portion of the mast, and a sprocket over which a chain connected at a first end to the load bearing unit and fixed at a second end relative to the mast portion is guided, the load bearing unit including or being adapted to include load handling means operable from a location spaced from the load bearing unit by control means including a flexible control line, the control line overlying the chain and being attached thereto by fasteners embracing respective link elements of the chain.

These fasteners may be fitted onto the associated link elements of a standard chain during assembly of the load lifting truck to provide an inexpensive alternative to the chain mentioned above which is adapted to take rivets.

In a preferred form of the invention, the fasteners are a snap fit onto the link elements for ease of assembly. For example, each fastener may have a pair of opposed arms engaging opposed ends of a respective link element, the arms being resiliently deformable for snapping the fastener onto the associated element.

Assembly of the control line on the chain may also be facilitated by employing a further snap fit connection between the line and each fastener. This is preferably achieved by providing each fastener with a resiliently deformable tongue arranged to hold the line against a back of the fastener from which the arms extend.

The invention is described further by way of example and with reference to the accompanying drawings, in which: Figure 1 is a side view of a truck embodying the invention; Figure 2 is a front view of the truck; Figure 3 is a fragmentary side view on an enlarged scale of the chain and a respective fastener illustrated in Figure 1; Figure 4 is a fragmentary front view on an enlarged scale of the chain and fastener; Figure 5 is a view taken in the direction of the arrow X in Figure 4 of the fastener alone; Figure 6 is a perspecive view of the fastener; and Figure 7 is a view similar to Figure 5 of a modification of the fastener illustrated in Figures 1 to 5.

Referring to Figures 1 and 2 initially, these show a truck 10 having a truck body 12 (only partially illustrated), a vertical mast 14 mounted on the front ofthetruck body 12, and a load bearing unit 16 mounted on the mast 14 for raising and lower loads.

The mast 14 is of the telescopic variety and has a pair of spaced upright members 18 which are fixed relative to the body 12 and which are braced by at least one cross-piece 20. A further pair of spaced upright members 22 are disposed between and in sliding engagement with the members 18 and constitute an extendable portion of the telescopic mast 14. Spanning the upper ends of the members 22 is a cross-bar 24 which in addition to bracing these extendable members also projects laterally beyond the fixed upright members 18.

In order to provide mountings for two blocks 26 such that these blocks lie laterally outside the members 18, a pair of bars 27 are provided which depend from the ends of the cross-bar 24. Two actuators, in the form of cylinders 28 having rams 30, are arranged to act on the blocks 26, and thus on the cross-bar 24, to control raising and lowering of the extendable portion of the mast 14. The cylinders 28 are secured to the members 18 in a conventional manner.

Turning now to the load bearing unit 16 this comprises a pair of bearing arms 32 mounted on a carriage 34 which includes runners (now shown) guided in tracks (not shown) in the extendable upright members 22 in a conventional fashion. The unit isis thus movable relative to the extendable members 22 as well as the fixed members 18. In addition to or instead of the arms 32, the carriage 34 may be provided with load handling fittings (not shown).

Movement of the carriage 16, like movement of the extendable members 22, is controlled by the cylinders 28. This is achieved through a chain and sprocket arrangement. Each of the blocks 26 carries a respective sprocket 36 as shown in Figure 2 so that, when the cylinders 28 are actuated to adjust the height of the blocks 26, the sprockets 36 also are raised or lowered. A respective roller-link chain 38 is guided over each sprocket and has a first end 40 connected to the load bearing unit 16 and a second end 42 secured to the associated cylinder 28. The second end 42 of each chain 38 is thus fixed relative to the truck body 12.It will be apparent, therefore, that, when the sprockets 36 are raised, for example, -underthe action of the cylinders 28, the first ends 40 ofthe chains 38 will also be raised and will draw the load bearing unit 16 up the tracks in the extendable upright members 22 to raise a load on the unit 16.

It is conventional to provide the carriage of the load bearing unitwith load handling fittings for effecting lateral or rotational movement of the load relative to the truck, for example, although this truck is adapted to receive such fittings they are not illustrated. These fittings are controlled from the truck body by way of flexible control lines 44 which rnay comprise -hydraulic and/or electrical supply lines. These control lines are connected to the load bearing unit 16 as illustrated and are arranged to follow the chains 38 over the sprockets 36 and thereafter to extend to a pair of anchorage points 46 either On the two cylinders 28 or on the two upright members 18. From the anchorage points 46 where the lines are held in place by way of clamps the lines -extend to a control valve (not illustrated) on the truck body 12.

Each line 44 overlies the associated chain 38 and is attached at intervals to the chain by way of fasteners 48 made of hardened and tempered spring steel.

Each chain is formed from a plurality of eight-shaped link plates 50 coupled together in an articulated manner by a plurality of pins 52. The plates 50 and pins 52 are arranged to form two different types of link elements, namely an inner link element 54 and an outer iink-etement 56. In each outer link element 56, three-of the plates 50 are joined in spaced relation by two of the pins 52, and each of the inner iink-elements 54 comprises four of the plates 50 arranged in two spaced pairs and joined by two pins -52. The pairs of plates 50 of the link elements 54 fit between the plates 50 of the link elements 56 as shown in Figure 4 and each inner link element is articulated to the shares its two pins 52 with a respective pair of outer link elements 56.The fasteners 48 are designed to embrace the inner link elements 54 and for this purpose are provided with two pairs of opposed arms 58. The arms 58 are resiliently deformable, in accordance with a preferred feature of this invention and as a result of each fastener being made of hardened and tempered spring steel, to enable the fasteners to be snapped onto the associated link elements 54 and are also profiled to conform to the ends of the plates 50 so as to provide a firm grip on these ends when the fasteners are in place.

Atongue 60, which is resiliently deformable, is also provided on each fastener to hold the associated control line 44 against a back 62 of the fastener from which the arms 58 extend. As shown in Figures 3 to 5, the tongue 60 lies generally perpendicularto the arms 58 over the back 62. In the embodiment illustrated in these figures, the fastener is designed to hold a twin hose line having two parallel hoses continuously joined together along a central line extending longitudinally of the hoses. In this instance, the tongue 60 is provided adjacent its free end 64 with a projection 66 extending towards the back 62 and arranged to seat between the two hoses to retain the line in place.Being resiliently deformable, the tongue 60 permits the associated line 44 to be snapped into position between the tongue and the back 62 so that fitting the line and the fasteners together is a simple matter.

As shown in Figures 2, the fasteners for each line are preferably arranged alternately with the free ends of the tongues 60 projecting first towards one side of the truck 10 and then towards the other side of the truck, for supporting the lines 44 laterally on both sides. In orderto give the lines further support, the tongues 60 of the fasteners are also preferably strengthed by inclining their free edges 68 away from their central portions.

Turning to Figure 6, an alternative fastener 70 is shown for receiving a single hose line. As before, this fastener is made of hardened and tempered spring steel and has pairs of opposed arms 58 to embrace the inner link elements 54. The fastener also has a back 62 and a resiliently deformable tongue. However, the tongue, 72, does not itself have a projection for locating the associated line but rather co-operates with a projection an the back 62 for this purpose. The projection may either take the form of a further tongue 74 upstanding from the back 62 as shown in full lines, or a bump 76 (illustrated with dashed lines) in the back 62.

Both the illustrated types of fastener are designed to fit onto a variety of standard chains without affecting the operation of the chain to provide an economic and simple solution to the problem of attaching a flexible line to a chain, particularly in the type of truck described.

Claims (11)

1. A load lifting truck having a mast, a load bearing unit mounted on the mast for vertical movement, an actuator for effecting movement of the load bearing unit, the actuator being arranged to raise and lower, in relation to a portion of the mast, and a sprocket over which a chain connected art a first end to the load bearing unit and fixed at a second end relative to the mast portion is guided, the load bearing unit including or being adapted to include loade handling means operable from a location spaced from the load bearing unit by control means including a flexible control line, the control line overlying the chain and being attached thereto by fasteners embracing respective link elements of the chain.

2. A truck as claimed in claim 1, wherein the fasteners are a snap fit over the respective link elements.

3. A truck as claimed in claim 2, wherein each fastener has a pair of opposed arms engaging opposed ends of the associated link element, the arms being resiliently deformable for snapping the fastener onto said element.

4. A truck as claimed in any preceding claim wherein a snap fit connection is provided between each fastener and the control line.

5. A truck as claimed in claim 4, wherein each fastener has a tongue arranged to hold the line against a back of the fastener, the tongue being resiliently deformable to permit the fastener and the line to be snapped together.

6. A truck as claimed in claim 5, wherein the line has two hoses and wherein the tongue of each fastener is provided with a projection arranged to seat between the hoses for locating the line in position.

7. A truck as claimed in claim 5, wherein the line has a single hose and wherein the tongue of each fastener is arranged to co-operate with a projection on the back of the fastener for locating the line in position.

8. A truck as claimed in any of claims 5 to 7, wherein the free edges of the tongue of each fastener are inclined relative to the central portion of the tongue.

9. A truck as claimed in any of claims 5 to 8, wherein the fasteners are arranged with the free ends of the tongues projecting alternately to one side and to the other of the chain.

10. A truck substantially as herein particularly described with reference to and as illustrated in Figures 1 to 5 or Figures 1 to 5 when modified by Figure 6 of the accompanying drawings.

11. A chain to which a flexible line is attached by means of a plurality of fasteners, each fastener comprising a back, a pair of opposed arms extending from the back and engaging opposed ends of a respective link element of the chain, and means engaging the flexible line to hold the line against the back of the respective fastener.