AND

SIMILAR HEAVY OBJECTS

This invention relates to an apparatus for lifting paving slabs, kerb stones and similar heavy objects and in particular to a self-propelled lifting apparatus for handling, lifting and laying paving slabs, kerb stones and similar heavy objects.

The manual handling of paving slabs and kerb stones and similar stone and concrete construction materials can be a difficult and dangerous operation. Therefore it is known to provide mechanical aids to assist the lifting and placement of such objects. While it is known to provide powered lifting devices on vehicles to aid the handling of such objects, such prior art vehicles typically require two operators, one to drive the vehicle and one to operate the lifting device. This increases labour costs and requires careful coordination of actions between the two operators.

According to the present invention there is provided a self-propelled lifting apparatus for lifting paving slabs, kerb stones and similar heavy objects, the apparatus comprising a wheeled or tracked chassis having a drive means and steering means permitting the apparatus to be moved around, a lifting device being provided for lifting and placing objects, such as paving slabs or kerb stones, wherein the apparatus can be manoeuvred via controls located on or adjacent the lifting device such that an operator can manually control the lifting device to lift and place a heavy object at a desired location while also controlling the movement of the apparatus while guiding the lifting device.

Said controls may be provided on a controller that is detachable or separable from the lifting device to enable remote control of the apparatus, preferably via wireless remote control. Preferably the lifting device comprises a vacuum lifting device mounted on an end of a cantilevered jib comprising a chamber having an open side adapted to be placed in contact with a surface of an object to be lifted, a peripheral seal being provided around said open side, the chamber communicating with a source of vacuum, such as a vacuum pump. Preferably the cantilevered jib is mounted on a mast supported on the chassis. The jib may be mounted on the mast to be traversed through 360° about the mast. The mast and jib may together define a hollow duct providing communication between a source of vacuum, such as a vacuum pump, and the vacuum lifting device. Brake or locking means may be provided for selectively restraining or locking the position of the jib with respect to the mast.

The apparatus enables a single operator to accurately lift and place a heavy object while controlling the movement of the chassis to enable such heavy objects to be placed at a desired location.

The chassis may also include a substantially horizontal deck portion upon which said heavy objects may be placed. Preferably a cutting device is provided on or adjacent the deck portion for cutting objects placed thereon. Preferably the cutting device is adapted to traverse across the deck portion. The cutting device may comprise a cutting disc. Preferably the cutting device is adapted to be located in a rest position clear of the deck portion when not in use. Clamp means may be provided for clamping a work piece or other object to be cut onto the deck portion of the chassis.

Preferably the chassis is provided with forwardly projecting forks at a forward end thereof for carrying said heavy objects, preferably located on a pallet. Preferably said lifting device is adapted to move said heavy objects from said forks to said deck portion of the chassis and subsequently from said deck portion to a location adjacent the chassis where the object is to be placed.

A lifting apparatus according to an embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which :-

Figure 1 is a perspective view of a self-propelled lifting apparatus in accordance with an embodiment of the present invention; Figure 2 is a detailed view of the lifting device of the apparatus of Figure 1 ;

Figure 3 is a sectional view through the head portion of the mast of the lifting device of Figure 2;

Figure 4 is a detailed sectional view of the head portion of the lifting device of Figure 2;

Figure 5 is a side view of the apparatus of Figure 1 showing the cutting disc in a retracted park position;

Figures 6 and 7 are side views of the apparatus of Figure 1 showing the cutting disc in its retracted and extended operative positions respectively; Figure 8 is a part sectional perspective view of the apparatus of Figure 1 showing the water tank;

Figure 9 is a detailed perspective view showing the front fork assembly of the apparatus of Figure 1 ;

Figure 10 is a sectional view through the front fork assembly of the apparatus of Figure 1 ;

Figure 1 1 is a side view of the fork assembly of Figure 1 showing the forks in their lowered position; and

Figure 12 is a side view of the fork assembly of Figure 1 showing the forks in their raised position. As shown in Figure 1 , a self-propelled lifting apparatus in accordance with an embodiment of the present invention comprises a motorised self propelled vehicle chassis defining a base platform 10 having at least one driven wheel and at least one steerable wheel. The apparatus may be powered by an electric motor or an internal combustion engine. As shown in Figure 2, a lifting device 12 is mounted on the base platform, preferably in the form of a vacuum lifting device communicating with a vacuum source, such as a vacuum pump. The lifting device 12 is mounted on a substantially horizontally extending cantilevered jib 14 which is free moving around a vertical mast 16. The mast 16 can maintained in the plumb (vertical) position to allow the operator to freely move the jib 14, and thus the lifting device 12, through 360° of unrestricted movement. In order to achieve this, the power to the lifting device 12 may be fed through the mast/jib pivot assembly via means of a suitable rotary coupling. Where the lifting device 12 comprises a vacuum lifting device, this may be achieved by forming the mast and jib from hollow tubes which, between them, define a duct, whereby the lifting device 12 may be coupled to a vacuum source, such as a vacuum pump. O ring seals 17 may be provided between the cooperating portions of the jib 14 and the mast 16 to prevent air leaks.

A brake is provided for holding the jib 14 in a desired position with respect to the mast 16. The brake may comprise a brake caliper 18 mounted on the mast 16, the caliper 18 engaging a disc 20 mounted on the jib 14, as shown in Figures 3 and 4. The brake may be arranged to automatically lock when the apparatus is at rest to prevent the job from swinging freely. For example, the piston or pistons of the caliper may be biased against the disc by biasing means, such as a spring, and may be forced away from the disc to release the brake by an actuating means, such as hydraulic pressure. Operation and movement of the lifting device 12 and also movement of the base platform 10 are both controlled using an incorporated radio controller 22, which may be docked on the lifting device 12 and which may be detached from the lifting device 12 when required to allow remote operation of the apparatus and lifting device.

The mast 16 is mounted on the self propelled base platform 10. The base platform 10, the lifting device 12 and the un-powered control of the position of the jib 14 around the mast 16 can be controlled at the point of lifting and lowering by a single operator who can see and feel the position of the objects which he/she seek to lift and lay.

As best shown in Figures 5 to 7, a cutting device or saw, preferably in the form of a disc cutter 24, is mounted on self propelled base platform 10 adjacent a flat cutting table/load carrying deck 26 defined on an upper surface thereof. The deck 26 can serve as a load carrying table and as a cutting deck upon which objects, such as kerb stones or paving slabs, located on the deck can be cut. The saw 24 is mounted on the base platform 10 via guide rails 28 slideable through a mounting block 29 on the platform 10, whereby the cutting disc can horizontally traverse the cutting table/deck between a retracted position, shown in Figure 6, and an extended, position shown in Figure 7. The cutting disc is adapted to pivot to an out of use position, shown in Figure 5, so that it can be moved clear of cutting table/load carrying deck 26.

A toggle clamp is provided adjacent the cutting disc for clamping a work piece to the cutting table/deck, the toggle clamp comprising a cantilevered arm 51 pivotally mounted to extend over the cutting table/deck and having a depending rod terminating in a clamp pad 52. An actuating arm 50 is mounted parallel to and above the cantilevered arm 51 , the actuating arm 50 being linked to the cantilevered arm 51 by an over-centre or toggle linkage 54, as best shown in Figure 5.

As can be seen from Figure 8, a water tank 28 is incorporated into the chassis of the base platform 10 for providing cooling water to the cutting disc and for suppressing dust. The water is returned to the tank 28 after use via a slotted drainage area 25 provided adjacent the cutting table/deck 26, where dust can be separated and the water recirculated to the saw as part of a dust suppression system. As shown in Figures 9 to 12, at a front end of the self propelled platform 10 there is mounted a set of foldable forks 32, adapted to lift and carry a pallet of laying material, such as kerb stones, allowing the operator to both carry the load and cut the material simultaneously. The forks 32 are mounted on the front of the chassis on a support frame 34 for movement between a lowered position, shown in Figures 9 to 1 1 , and a raised position as shown in Figure 12, via pivotally mounted upper linkage arms 36 and lower guide tracks 38. The lower side of the support frame 34 is mounted on vertical guide tracks 38 via support bearings 40, the guide tracks 38 being arranged such that the angle of the forks 32 varies as the forks 32 move between their lowered and raised positions, between a slight downwardly inclined orientation when in their lowered position, to facilitate insertion of the forks beneath a pallet, and an upwardly inclined orientation when in their raised position, to better retain material on the forks during movement of the apparatus. The lifting device 12 is capable of lifting objects, such as kerb stones or paving slabs, from the forks 32 onto the deck 26 and/or from either location to a laying position.

The invention is not limited to the embodiment(s) described herein but can be amended or modified without departing from the scope of the present invention.