GB2165523A

GB2165523A - Improvements relating to block handling apparatus

Info

Publication number: GB2165523A
Application number: GB08525304A
Authority: GB
Inventors: Donald George Ross
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-10-13
Filing date: 1985-10-14
Publication date: 1986-04-16
Also published as: GB2165523B; GB8525304D0

Abstract

The apparatus has two pairs of mutually hinged arms (6;21,22) with jaws (1;23) for engaging opposite sides of a kerbstone (K) or paving slab (P). A toggle linkage (8,9; 24,25) with an over-centre action connects the arms and can be operated to clamp the jaws. The arms are at opposite ends of a shaft ((2);19) with eyes (4;20) through which the prongs of a fork lift device can be inserted to raise the apparatus and a gripped block off the ground. This fork lift device may be mounted on the front of a manually operated, wheeled trolley enabling the block to be manouvred with precision. The trolley can be adapted for other tasks, such as raising manhole covers. <IMAGE>

Description

SPECIFICATION Improvements relating to block handling apparatus This invention relates to block handling apparatus and has been developed primarily for lifting, manoeuvring and placing kerbstones and paving slabs.

These are extremely heavy, and have no convenient part to grip. Although they can be handled in bulk by palletising them and using powered lifting equipment, when it comes to laying them they each have to be picked up and placed individually.

This is almost literally back-breaking work, and there is a need for handling equipment which can ease this problem, and also speed up the work of laying.

According to one aspect of the present invention there is provided apparatus for handling blocks such as kerb-stones or paving slabs, comprising mutually pivoted arms with downwardly projecting jaws for gripping a block on opposite sides, a toggle mechanism with an over-centre locking characteristic for actuating the arms, and suspension means for engagement by a fork lift, crane hook or other lifting device.

In the preferred form, there are two pairs of arms, each with jaws, in substantially parallel relationship pivoted on a common shaft. The suspension means are conveniently carried by this shaft, symmetrically between the pairs of arms. Advantageously they comprise two eyes or loops above the shaft and adjustable to face transversely thereto or in alignment parallel thereto.

Preferably each pair of arms will have its individual toggle mechanism. Also, each pair of arms may have the facility to skew to a limited extent from the parallel relationship, and the jaws themselves may be pivotally mounted on their arms to turn about a generally vertical axis. This allows gripping of curved kerb-stones.

The arms may be in the form of bell-crank levers mutually pivoted at the elbows, the jaws being on the lower ends of these levers and the toggle mechanism being linked between the upper ends thereof, conveniently with one link extended to form an operating handle. This is the preferred form for kerb-stones.

Alternatively, the arms may be straight bars mutually pivoted in variable X or Y-formation, the toggle mechanism being linked between the lower end of one bar and the upper end of another, conveniently with one link extended upwardly to form an operating handle. This is the preferred form for paving slabs.

To make handling and fitting easier spring means may be provided to urge the jaws together and to tend to straighten the toggle mechanism.

According to another aspect of the present invention there is provided a manually operated trolley comprising a chassis with a front-end load carrying assembly, a handle at the rear end, and two sets of wheels, a forward set being of smaller diameter than a rear set and their axes being such that, in a load delivery position on a level surface, only the forward, small wheels bear on that surface while, in a load carrying position with the handle pressed down, only the rear, larger wheels bear on said surface.

Preferably the chassis is generally L-shaped with an upright leg at the forward end and the other leg, which may be telescopically adjustable in length to increase the leverage if desired, extending rearwardly to provide the handle. The rearmost portion of this other leg may have a bend with a grip at the free end, this portion being invertible for the bent extremity to project upwardly or downwardly thereby providing alternative grip heights.

Preferably the forward, small wheels will be outside the rear, large wheels, the wheels overlapping in side view.

Conveniently the transverse buffer plate will provide a front-end base for the load carrying assembly and it may afford alternative positions for that assembly.

In one form, the load carrying assembly is a fork lift structure with a long central prong and two shorter prongs flanking it. This can co-operate with the block handling apparatus outlined above.

Another useful form is a cradle for manhole cover keys. In essence, this may be a beam providing a series of seats for T-shaped keys with the handles supported either transversely to or aligned with the beam.

For a better understanding of the invention one embodiment will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of apparatus for gripping kerbstones, Figure 2 is a front elevation of the apparatus of Figure 1, Figure 3 is a side elevation of apparatus for gripping paving slabs, Figure 4 is a side elevation of a trolley for use with the apparatus of Figures 1 and 2 or that of Figure 3, Figure 5 is a perspective view of a fork lift assembly for the trolley of Figure 4, Figure 6 is a side view of the assembly of Figure 5 attached to the trolley in a different manner, and a modification of that assembly and Figure 7 is a perspective view of a manhole lifting attachment for the trolley for Figure 5.

The apparatus of Figures 1 and 2 has two pairs of downwardly extending jaws 1 carried in a substantially parallel arrangement at opposite ends of a shaft 2 by toggle devices 3. The apparatus can be lifted by means of eyes 4 at the upper ends of rods 5 secured at symmetrical intermediate points on the shaft 2.

Each toggle device 3 comprises two bell-crank levers 6 pivoted on a respective reduced end portion 7 of the shaft 2 to form an X. The upper arms of the levers are coupled by pivoted links 8 and 9, the link 9 being extended beyond its connection to one of the levers 6 to form an operating handle.

The lower arms of the levers 6 are coupled by a light spring 10 which tends to straighten out the toggle links 8 and 9 and keep the device in a stable out-of-use condition. In practice, however, this spring has been omitted without adverse results.

At their lower ends these arms carry respective jaws 1 through hinge connections 11 allowing each jaw to swing about a substantially vertical axis, assuming the shaft 2 is horizontal. In this example, such connection 11 comprises two interengaged devises with a vertical pin through the flanges.

The vertical extend of the hinge connection is such that the jaw cannot swing in the plane of Figure 1 relative to the lever 6 to which it is connected.

Each jaw 1 may simply be a steel bar, of T-section in this example, and although serrations or other gripping formations may be provided on the inner surface, they have been fount not to be essential.

Each toggle device 3 is urged against a shoulder of the shaft 2, where the reduced end portion 7 begins, by a coil spring 12 captive by a washer 13 and a split pin 14. This arrangement allows each toggle device some latitute for tilting with respect to the shaft 2, the engagement of the reduced end portion 7 through the elbows of the levers being loose.

The rods 5 extend through transverse bores in the shaft 2, and are secured by nuts 15. These allow the rods to be twisted about their longitudinal axes, and therefore enable the eyes 4 to face either as shown in Figure 1, parallel to the shaft 2, or as in Figure 2, transverse to that shaft. These eyes are for receiving the prongs of a fork-lift device described below.

In operation, for gripping a kerbstone K, the handle portion of the link 9 is pressed downwardly to draw the upper arms of the levers 6 together and thus separate the jaws 1, allowing them to be lowered over the central position of the kerbstone as far as possible. The handles are then pulled upwardly, so that the links 8 and 9 straighten and then move slightly over-centre into a shallow V configuration, indicated somewhat exaggeratedly by a broken line. This brings the lower arms of the levers towards each other and causes the jaws firmly to engage the kerbstone. The fork-lift device can then engage the eyes 4 and lift and manoeuvre the kerbstone.

Not all the kerbstones are straight, but the device can accommodate to curved ones, both by the jaws 1 pivoting about their connections 11, and also by the slight skew movement allowed to the toggle device 3.

A different gripping device but operating on similar principles is shown in Figure 3, this one being intended for handling paving slabs. There are two toggle devices 18 (only one of which is seen) at the ends of a shaft 19 which has lifting eyes 20 substantially as described above. However, each toggle device 18 comprises two straight bars 21 and 22 mutually pivoted on the shaft 19 about their centre points to form a shallow but variable X. The lower ends of these bars each have a finger in the form of a small plate 23 welded on at an angle to grip opposide sides of a paving slab P. The toggle linkage is connected between the lower end of the bar 21 and the upper end of the bar 22, the lower link 24 being short and the upper link 25 being extended upwards to provide an operating handle.A spring 26, equivalent to the spring 10 and generally more desirable in this embodiment, spans the lower ends of these bars. it will be seen from the figure that pressing the handle to the right releases the slab while pulling it to the left after such release clamps the fingers 23 to opposite sides of the slab P with an over-centre action.

The upper end of the bar 21 is redundant and need not be provided, in which case the arms would form a variable Y. However, it does provide quite a useful additional handle. It would be possible to have a common actuation of the toggle devices, or even to have a single broad device, but two separately operabie ones are thought to give a better and safer grip.

Referring now to Figures 4 and 5, there is shown a trolley equipped with a fork lift attachment for engagement with the lifting devices just described.

The trolley has a simple chassis in the form of a generally L-shaped beam 31 of box section, the shorter leg 32 being upright in normal use and the longer leg 33 extending rearwardly and slightly upwardly from the upper end of the leg 32.

A handle 34 is telescoped into the rear end of the leg 33 and can be clamped by a screw 35 to provide a selected extension. In full lines it is shown in the short condition, while the broken lines indicate various longer conditions. The handle 34 has a shallow bend towards its rear end, and it can be set so that this extremity 36 slopes either upwardly or downwardly to suit the height of the user and the amount of extension. A T-bar 37 provides the actual grip.

The trolley has two sets of wheels 38 and 39 which, in side view, have an overlapping relationship. The wheels 38 are smaller than the wheels 39, out-board of them, and set slightly forwards in relation to them. When the trolley is in the position shown, which corresponds to that for actually picking up and setting down a load, it is these forward wheels 38 that rest on the ground, while the wheels 39 have slight clearance, of the order of 5 mm. However, when the trolley is being manoeuvred and carrying its load, the handle 34 is pressed down, bringing the wheels 39 into contact with the ground and raising the wheels 38 off it.

The wheels 39 are mounted on either side of a short arm 40, projecting rearwardly from the lower end of the leg 32. On the forward side of this leg there is a rectangular buffer plate 41, square-on to the direction of forward motion, and the wheels 38 are mounted on inclined legs 42 extending downwardly and rearwardly from this plate.

The buffer plate 41 can serve as a mounting for a fork-lift assembly as best seen in Figure 5. This has a base plate 43 which can be bolted at selected heights to the front of the plate 41, which has sets of holes 44 for that purpose. A square section tube 45 projects forwardly from the centre of the plate 43 and into it telescopes the stem 46 of a T-member whose cross bar 47 has three forwardly projecting spikes or prongs 48 and 49. The central one 48 is longer than the two outer ones 49 and is for engagement with the eyes 4 or 20 when set in the Figure 1 attitude, in which case the trolley is manoeuvred up lengthwise of the kerbstone for the spike 48 to extend through both eyes. The spikes 49 are set apart at a spacing corresponding to that of the eyes 4 or 20 and are used when these are in the attitude of Figure 2.This will be the normal usage, since the load will be more stable, and it will be more practical for kerbstones in particular.

The T-member 46, 47 can be adjusted and set to the desired amount of forward projection by a set screw 50.

Once the spike or spikes are engaged, pressing down on the handle 34 will pivot the trolley first on the wheels 38 and then on the wheels 39, thereby raising the load from the ground.

Use with the paving slab attachment of Figure 3 is similar and will not be described in detail.

The two pairs of wheels 38 and 39 are advantageous in achieving better control and initial leverage than would be available just with one pair of wheels, although a trolley so equipped would be workable. The small pair of wheels 38 are immediately behind the buffer plate 41 to create a pivot as near the load as possible, thus easing the initial lift. As the trolley tilts, the weight of the load is thrown backwards to a certain extent, and is eventually taken by the large wheels 39, which can cope better with rough or uneven ground.

The fork lift assembly is removable, and may be replaced by other load bearing means, or it may be adjusted to a different attitude as shown in Figure 6(a). Here, an L-section bracket 51 is bolted to the front of the buffer plate 41 to provide a horizontal projecting flange. The fork-lift assembly is then bolted to this flange so that the spikes project upwardly. Alternatively, an integral assembly 52 may be fitted as shown in Figure 6(b).

These may be used for handling kerbstones with the device of Figures 1 and 2. If the fork-lift assembly was set as in Figure 5, the kerbstone would be suspended some distance in front of the plate 41, thus requiring considerable effort and/or the longest available handle configuration to lift and manoeuvre it. However, with the Figure 6 arrangement, the rods 5 can be swung over and, when engaged by the spikes 49, the kerbstone will be held close in against the plate 41. It is then much easier to lift.

In order to engage the eyes 4 with the spikes 49, the trolley will have to be tilted forward quite substantially on the wheels 39, but as it is tilted backwards again, the eyes 4 will slide down the spikes 49 until they bear on the base plate 43.

It will be understood that the gripping devices, although designed in conjunction with the trolley, may be lifted and handled by other means, such as a crane which can hook into the eyes 4 or 20.

An alternative attachment is shown in Figure 7, this being for raising manhole covers. The same base plate 43 and tube 45 can be used, but into the latter there telescopes the stem of a T-shaped assembly 53. The cross member 54 of this is horizontal and comprises two parallel flat bars 55 in vertical planes held apart by spacers 56 at each end and at the mid-length. Each bar has a series of apertures 57 along its length and a series of notches 58 along its upper edge. Cross pins 59 can be entered in any of the apertures 57 to span the gap between the bars. Keys 60 for manhole covers are generally of T-form. The stem can be passed down between the bars 55 so that the key head is cradled by opposed notches 58 as shown at the right hand end of Figure 7. The lower end of the key then projects below the cross member 54 and can be engaged in a recess in a manhole cover.

The lifting and manoeuvering technique is similar to that described above. Alternatively, a cradle can be formed by two closely spaced pins 59, in which case the key head will lie lengthwise of the cross member 54 as shown at the left hand end of Figure 7. Thus the attachment provides a wide range of key positions in a choice of attitudes, sufficient for almost any manhole cover.

Claims

1. Apparatus for handling blocks such as kerbstones or paving slabs, comprising mutually pivoted arms with downwardly projecting jaws for gripping a block on opposite sides, a toggle mechanism with an over-centre locking characteristic for actuating the arms, and suspension means for engagement by a fork lift, crane hook or other lifting device.

2. Apparatus as claimed in claim 1, wherein there are two pairs of arms, each with jaws, in substantially parallel relationship.

3. Apparatus as claimed in claim 2, wherein the arms pivot on a common shaft.

4. Apparatus as claimed in claim 3, wherein the suspension means are carried by the shaft.

5. Apparatus as claimed in claim 4, wherein the suspension means are symmetrically disposed between said pairs of arms.

6. Apparatus as claimed in claim 4 or 5, wherein the suspension means comprise two eyes or loops above said shaft and adjustable to face transversely thereto or in alignment parallel thereto.

7. Apparatus as claimed in any one of claims 2 to 6, wherein each pair of arms has its individual toggle mechanism.

8. Apparatus as claimed in any one of claims 2 to 7, wherein the pairs of arms have the facility to skew to a limited extent from their parallel relationship.

9. Apparatus as claimed in any one of claims 2 to 8, wherein the jaws are pivotally mounted on their arms to turn about generally vertical axis.

10. Apparatus as claimed in any preceding claim, wherein the arms are in the form of bellcrank levers mutually pivoted at the elbows, the jaws being on the lower ends of these levers and the toggle mechanism being linked between the upper ends thereof.

11. Apparatus as claimed in claim 10, wherein one link of the toggle mechanism is extended to form an operating handle.

12. Apparatus as claimed in any one of claims 1 to 9, wherein the arms are straight bars mutually pivoted in variable X or Y-formation, the toggle mechanism being linked between the lower end of one bar and the upper end of the other.

13. Apparatus as claimed in claim 12, wherein one link is extended upwardly to form an operating handle.

14. Apparatus as claimed in any preceding claim wherein spring means are pivoted to urge the jaws together and to tend to straighten the toggle mechanism.

15. A manually operated trolley comprising a chassis with a front-end load carrying assembly, a handle at the rear end, and two sets of wheels, a forward set being of smaller diameter than a rear set and their axes being such that, in a load delivery position on a level surface, only the forward, small wheels bear on that surface while, in a load carrying position with the handle pressed down, only the rear, larger wheels bear on said surface.

16. A trolley as claimed in claim 15, wherein the chassis is generally L-shaped with an upright leg at the forward end and the other leg extending rearwardly to provide the handle.

17. A trolley as claimed in claim 16, wherein said other leg is telescopically adjustable in length.

18. A trolley as claimed in claim 17, wherein the rearmost portion of said other leg has a bend therein with a grip at the free end, this portion being invertible for the bent extremity to project upwardly or downwardly, thereby providing alternative grip heights.

19. A trolley as claimed in any one of claims 15 to 18, wherein the forward small wheels are outside the rear large wheels.

20. A trolley as claimed in claim 19, wherein the wheels overlap in side view.

21. A trolley as claimed in any one of claims 15 to 20, wherein a transverse buffer plate provides a front-end base for the load carrying assembly.

22. A trolley as claimed in claim 21, wherein the buffer plate affords alternative mounting positions for the load carrying assembly.

23. A trolley as claimed in any one of claims 15 to 22, wherein the load carrying assembly is a fork lift structure.

24. A trolley as claimed in claim 23, wherein the fork lift structure has a long central prong and two shorter prongs flanking it.

25. A trolley as claimed in claim 23 or 24, in combination with apparatus as claimed in any one of claims 1 to 14.

26. A trolley as claimed in any one of claims 15 to 22, wherein the load carrying assembly is a cradle for manhole cover keys.

27. A trolley as claimed in claim 26, wherein the cradle has a beam providing a series of seats for T-shaped keys, with the key handles supported either transversely to or aligned with the beam.

28. Apparatus for handling blocks substantially as hereinbefore described with reference to Figures 1 and 2, or Figure 3 of the accompanying drawings.

29. A manually operated trolley substantially as hereinbefore described with reference to Figure 4 of the accompanying drawings.

30. A trolley as claimed in claim 29, in combination with a fork lift device substantially as hereinbefore described with reference to Figure 5 or 6.

31. Apparatus as claimed in claim 28, in combination with the trolley and fork lift device as claimed in claim 29.

32. A trolley as claimed in claim 29, in combination with a manhole lifting device substantially as hereinbefore described with reference to Figure 7.