GB2069454A

GB2069454A - Lifting devices

Info

Publication number: GB2069454A
Application number: GB8104755A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-02-14
Filing date: 1981-02-16
Publication date: 1981-08-26
Also published as: GB2069454B

Abstract

A manually operable device of the kind comprising a base frame (1) having ground wheels (2, 3), an upper frame (7) slidable vertically on the base frame and provided with means for clamping a heavy object to be lifted and transported, a manually operable lever (27, 28) pivotally mounted on the box frame for movement about a horizontal axis (29) to raise the upper frame and releasable means for locking the upper frame in its raised position, is adapted for lifting and transporting oil drums and similar rimmed containers by providing it with clamping means in the form of upper and lower claws (13, 14) mounted on the upper frame for relative movement towards and away from one another, springs tending to close the claws and a linkage (22, 23, 24) so connecting the claws that they open automatically to admit the rim of a container upon engagement therewith and close tightly about the rim when the upper frame is raised to lift and hold the container clear of the ground. <IMAGE>

Description

SPECIFICATION Lifting devices This invention relates to manually operated devices for lifting and transporting heavy objects and is particularly concerned with such devices of the kind, hereinafter referred to as "the kind described", comprising a base frame having ground wheels, an upper frame slidable vertically on said base frame and provided with means for clamping an object thereto, a manually operable lever pivotally mounted on said base frame for movement about a horizontal axis to raise said upper frame and releasable means for locking said upper frame in its raised position.

A device of the kind described capable of lifting and transporting gas cylinders for use in hospitals and for industrial purposes already forms the subject of British Patent No. 1297382 and has clamping means which comprises a pair of jaws pivotally mounted on the upper frame for movement about a common vertical axis and urged into open position by springs acting between the jaws and the upper frame, an operating member slidably mounted on the upper frame and engaging the backs of the jaws and a lead screw and nut mechanism operable by a rotary handle for moving the operating member in a direction to close the jaws around a gas cylinder.

It is the object of the present invention to provide a device of the kind described for lifting and transporting oil drums and similar rimmed containers, said device having clamping means which is operable automatically to grip the rim of an oil drum or like container upon movement of the device into engagement with the container.

To this end, according to the invention, the clamping means comprises upper and lower claws mounted on the upper frame for relative movement towards and away from one another, spring means tending to close said claws and a linkage so connecting said claws that they open automatically to admit the rim of a container upon engagement with the latter and close tightly about said rim when the upper frame is raised to lift and hold the container clear of the ground.

One embodiment of the invention will be described, by way of example, with reference to the accompanying diagrammatic drawings which show a device for lifting and transporting oil drums and like rimmed containers and in which: Figure lisa side elevation of the device showing the upper frame in its lowermost position and a drum gripped by the claws; Figure 2 is a front elevation of the device; Figure 3 is an enlarged detail looking from the left-hand side of Fig. 2 showing the claws closed before engagement with the rim of a drum; Figures 4 and 5 are enlarged detail views of the claws in the closed and open position respectively; and Figures 6 and 7 are enlarged detail views showing the height adjusting mechanism during and after adjustment respectively.

As shown, a base frame 1 mounted on fixed wheels 2 and a steerable wheel 3 is cut away at the front to accommodate the lower end of an oil drum 4. The base frame 1 carries two upright members 5 (Fig. 2) on which are slidably mounted tubular members 6 of an upper frame 7 which supports a box 8 for a longitudinally adjustable rack 9 which can be located in any of its positions of adjustment by a fixed pin 10 passing through the box and engaging between any two adjacent rack teeth. The rack is secured in its position of adjustment by a threaded bolt 11 (Figs. 6 and 7) passing through the rear wall of the box into engagement with the rack.The latter is provided at its upper end with a box 12 housing a pair of identical upper claws 13 having inclined lower faces 1 3a and a single lower claw 1 4 which, with the claws 13, projects through an opening in the front of the box for engagement with the rim of a drum to be transported. Within the box 12, the upper claws 13 are connected together by pins 1 5 and 1 6 (Figs. 4 and 5) of which the latter passes through and is slidable vertically in slots 1 7 (Fig. 3) in the side walls of the box and is connected by tension springs 18, only one of which is shown in Fig. 3, to a stationary pin 19 passing through apertures 20 in the side walls of the box.The lower claw 14 carries a pin 21 which is connected to the pin 16 by a link 22 sandwiched between the claws 13 and to the pin 19 by a pair of links 23, only one of which is shown in Figs. 4 and 5, arranged on opposite sides of the claw 14. The pin 1 9 is connected to the pin 15 by a link 24.

Secured to the outer surfaces of the frame members 6 are blocks 25, the lower ends of which are engaged by rollers 26 rotatably mounted at the lower ends of the limbs 27 of a U-shaped handle 28 which limbs are pivoted at 29 in brackets 30 on the base frame 1. Movement of the handle about its pivots 29 in a clockwise direction, as looked at in Fig. 1, acts through the blocks 25 to raise the frame 7 relative to the base frame 1 while movement of the handle in the anticlockwise direction permits the frame 7 to return to the position shown in Fig. 1.

In order to retain the upper frame 7 in its raised position it is preferred to employ locking means (not shown) of the kind forming the subject of British Patent No. 1297383 and comprising a catch rotatably mounted on the upper frame and an abutment mounted on the base frame 1 and operable upon upward movement of the upper frame relative to the base frame to rotate the catch into locking engagement with a shoulder on the base frame.

In operation, the rack 9 is adjusted, as shown in Fig. 6, to bring the claws to the level of the rim of a drum 4 to be moved, the device is wheeled towards the drum and when the rim of the latter is engaged by the inclined lower surfaces 1 3a of the upper claws 1 3 these claws are raised, against the action of the springs 1 8, to allow the rim to pass between the open claws and then snapped down by the springs to enclose the rim. The drum is then lifted by operation of the handle 28 causing the lower claw 14 to lock under the rim and the downward pressure exerted by the drum on the claw linkage forces the claws together to lock them to the rim.Lifting continues until the catch of the locking means makes locking engagement with the shoulder on the base frame 1 , whereupon the handle 28 can be returned to its original position and the device wheeled, with the aid of a steering handle 31, to the point at which the drum is to be unloaded.

While the frame 7 is in its upper position the weight of the drum acting upon the claw linkage ensures that the drum cannot be released from the device and to prevent the drum from swinging a guide 32 is provided at the lower end of the frame 7 to laterally confine the lower end of the drum.

Upon reaching the unloading point, the handle 28 is again operated to release the catch of the locking means and is then moved in the opposite direction to enable the drum to be lowered to the ground. Upon reaching the ground the pressure on the lower claw 14 is relieved and the upper claws 13 can be lifted free of the rim to release the drum.

Claims

1. A device of the kind described, wherein the clamping means comprises upper and lower claws mounted on the upper frame for relative movement towards and away from one another, spring means tending to close said claws and a linkage so connecting said claws that they open automatically to admit the rim of a container upon engagement with the latter and close tightly about said rim when the upper frame is raised to lift and hold the container clear of the ground.

2. A device according to Claim 1, having a pair of identical, transversely spaced upper claws and a single lower claw arranged between said upper claws, said claws being housed in a claw box adjustable in a substantially vertical plane with respect to said upper frame and having an opening through which said claws project for engagement with a container.

3. A device according to Claim 2, wherein said upper claws are connected together for simultaneous parallel movement by two pins, one of which is slidably mounted in substantially vertical slots in opposite sides of said claw box.

4. A device according to Claim 3, wherein said spring means comprises a pair of substantially vertical tension springs secured at their upper ends to said slidably mounted connecting pin and at their lower ends to a third transverse pin fixedly mounted in said claw box and connected by elements of said linkage to the other connecting pin for the upper claws and to a fourth transverse pin carried by said lower claw.

5. A device according to Claim 4, wherein said linkage comprises a first link located between said upper claws and connecting said fourth pin to said slidably mounted connecting pin, a pair of second links arranged on opposite sides of said lower claw and connecting said fourth pin to said third pin and a third link connecting said third pin to the other connecting pin for said upper claws.

6. A device according to any one of Claims 2 to 5, wherein said claw box is mounted on the upper end of a substantially vertical rack passing through, and adjustable longitudinally with respect to, a box secured to said upper frame and provided with a pin which cooperates with the rack teeth to locate the rack in any adjusted position and a manually operable bolt for securing the rack in any position to which it has been adjusted.

7. A manually operable device for lifting and transporting heavy objects, substantially as hereinbefore described with reference to or as shown in the accompanying drawings.