The invention relates to a device to be mounted to the mast of a fork lift truck comprising means for co-operating with guide means on the mast, means for turning the device through at least 180° with respect to the mast, a first vertical frame having protruding carrying forks and a second frame having protruding clamping forks, wherein the first frame is vertically movable with respect to the second frame, and a shifting device is adapted to move between the forks in the longitudinal direction of the forks. This device is known from US-A-3 438 525.
Such a known device is mounted on the mast of the fork lift truck and serves to discharge a load transported on a pallet so that the pallet can be retained. To this end the load transported on a pallet is clamped by the vertical movement of the first frame between the forks of the first and the second frame, the whole device being then turned through 180° with respect to the mast, the clamp and the carrying fork being moved slightly away from one another, whilst finally with the aid of the shifting device the load is shifted from the clamping forks onto the deposition surface. The pallet then remains on the carrying forks.
The known device is not adapted to be mounted on the fork lift truck transportable on a van. With this construction of the assembly the part protruding from the rear side of the van is too large so that the provisions of safety can no longer be satisfied. The invention has for its object to render the known device suitable for mounting on a transportable fork lift truck.
According to the invention this is achieved in that the second frame is arranged in the same vertical plane as the first frame and the shifting device is formed by a pivotal linkage which is also located in said vertical plane in the retracted position.
By the steps taken in accordance with the invention a very compact construction is obtained so that despite the presence of the device the extension of the part of the fork lift truck protruding from the rear side of the van can be drastically reduced, that is to say, in practice to about 240 mm.
In one embodiment an arm of the pivotal linkage is pivotally journalled in a beam of the first frame. The movement of the first frame can be guided in the second frame. Since the second frame is rotatable with respect to the mast, the whole device is rotatable with respect to the mast.
The invention will be described more fully with reference to the drawings.
The drawings show in:
On a van 1 (shown partly) can be deposited a fork lift truck of known type by slipping the carrying forks 3 into the appropriate beam 4 and by subsequently causing the frame of the fork lift truck to move upwards. The device 5 embodying the invention can be mounted on this known, transportable fork lift truck.
The device 5 is mounted on the mast 6 of the transportable fork lift truck. The device 5 embodying the invention comprises a first frame 9 of vertical and horizontal beams, from which protrude carrying forks 3. The device 5 furthermore comprises a second, vertical frame 7, from which protrude the clamping forks formed in this case by a plate 10. By means of guide rollers 11 the first frame 9 can be vertically guided in the second frame 7. In its vertical movement the first frame is controlled by hydraulic means, for example, a plunger 12. With the first frame is connected a shifting device 13 formed by a pivotal linkage comprising the arms 14 and 15. The linkage is controlled, for example, by a hydraulic or pneumatic plunger 16. With respect to the mast the second frame 7 can be reversed, since it is adapted to rotate by a shaft 17 in a hub 18. The movement of the frame and hence of the whole device is performed by the rolling movement of a driving gear wheel 19 on the inner toothing 20 of the shaft 17.
The device operates as follows: The carrying forks 3 of the first frame are slipped into a pallet 21, on which a load is deposited. Subsequently, with the aid of the plungers 12, the carrying forks 3 are lifted until the load rests on the clamping forks 10. Then with the aid of the reversing mechanism 17, 18, 19 and 20 the device embodying the invention is turned through 180° so that the position shown in Fig. 3 is obtained. Then the first frame is moved vertically upwards so that the load is set free of the pallet 21 and bears on the clamping forks 10. Then with the aid of the plunger 16 the shifting device 13 is actuated so that the load is slipped in the direction indicated in Fig. 3 from the clamping forks 10 onto a deposition surface, for example, 22. Subsequently the device is again turned and the pallet can be deposited back on the van. Owing to the compact construction in accordance with the invention the added length of the transportable fork lift truck 23 (see Fig. 4) is limited to about 240 mm.