EP0663368A1

EP0663368A1 - Lifting device

Info

Publication number: EP0663368A1
Application number: EP94101219A
Authority: EP
Inventors: Esko Vaske
Original assignee: Vaske-Lift Oy
Current assignee: VASKE-LIFT OY
Priority date: 1994-01-13
Filing date: 1994-01-27
Publication date: 1995-07-19
Also published as: FI940157A0

Abstract

A lifting device for lifting and transporting goods, comprising a vertical frame (1), a transversal support (2) resting on the top end thereof, on the lower end of said frame, prongs (4) movable horizontally carried by slides (3) and which can be pushed in under the goods to be lifted, a flap mechanism (5) supported by the top end of the frame for retaining from above the goods which is being lifted, and a hydraulic cylinder (6) for operating the prongs and the flap mechanism. The flap mechanism (5) comprises a lever (7) supported by the frame or by the support and carrying on one end a flap (8) steadying the load. In addition, the hydraulic cylinder is substantially vertical and rests with its top end against the lever and with its lower end, against a redirecting means (9) communicating with the prongs for moving the flap and the prongs by means of one hydraulic cylinder.

Description

The present invention concerns a lifting device as defined in the preamble to Claim 1.
Prior technology in the field of the invention is represented by the Finnish Patent No. 64788, in which is disclosed a device for handling burdens, to be used in conjunction with cranes. The device is used, for instance, when loading or unloading bricks or any other kind of stacked piece goods. The device comprises a frame, prongs meant to be placed under the burden, and a flap pressing down on the burden from above. The prongs and flap are connected to one and the same hydraulic cylinder by mediation of a linkage mechanism, in such manner that when a burden is being picked up the prongs first move in under the burden and the flap is then pressed against the burden. When the burden is being delivered, the flap first opens and the prongs move out from under the burden thereafter.
The device that has been disclosed has primarily been designed for lifting single piles of bricks and therefore a relatively short horizontal motion of the prongs is obtained with the linkage mechanism therein provided. If it is desired that the horizontal travel of the prongs be more extensive, i.e., when for instance a standard truck pallet is lifted, or an even greater load, the linkage mechanism and hydraulic cylinder used in the device will increase so much in length that the dimensions of the device behind the frame, or on the side which is opposite to the burden being lifted, relative to the vertical frame would increase significantly. This makes the use of the device extremely cumbersome or outright impossible in cramped lifting and loading conditions.
The object of the invention is to eliminate the drawbacks mentioned. It is a particular object of the invention, to disclose a novel lifting device in which comparatively long prongs can be used and they can be arranged to move through a comparatively long horizontal distance without substantially increasing the dimensions of the lifting device in the longitudinal direction of the prongs.
Regarding the features characterizing the invention, reference is made to the Claims section.
The lifting device of the invention for lifting and transporting goods comprises a vertical frame carrying on its top end a transversal support, on the lower end of said frame movable prongs movable in horizontal direction, carried by slides, and which can be pushed in under the goods, and a flap mechanism carried on the top end of the frame for steadying the goods from above. The lifting device further comprises a hydraulic cylinder for operating the prongs and the flap mechanism. As taught by the invention, the flap mechanism comprises a lever resting on the frame or on a support which is fixed in relation to the frame, carrying on one end a flap which rests against the load, and in addition the hydraulic cylinder is substantially vertical and rests with its upper end against said lever and with its lower end against a redirecting means, for moving the flap as well as the prongs with one and the same hydraulic cylinder.
The redirecting means on the lower end of the hydraulic cylinder consists advantageously of a suitable redirecting mechanism by which the substantially vertical movement of the hydraulic cylinder can be transmitted and redirected to result in a substantially horizontal movement of the prongs carried on the lower end of the frame.
The transversal support advantageously extends from the frame out over the load which is being handled, that is, to a point above the flap carried by said lever, to the support belonging a lifting hook, a suitable eyelet or any equivalent member for hoisting the lifting device by this member e.g. with the aid of a crane.
The support advantageously extends from the frame to a point above the load and the flap, obliquely upward. The hoisting hook is then carried with the aid of suitable sliding rails by the support and moves along the sliding rails. To the hoisting hook is connected e.g. a spring-like tension member which pulls it downward along the sliding rails, whereby the hoisting hook will move upward along the support, depending on the weight of the load, in such manner that the lifting device will keep substantially level, independent of its total weight.
Advantageously, the transversal support also extends from the frame, at its top end, to the side opposite to the load and flap, thus forming an extension, to which the lever is pivotally attached by one end. The hydraulic cylinder is then, advantageously, pivotally joined to the lever at a point between the pivot point of lever and extension and the frame.
Advantageously, the lever is connected to the transversal support, on its part on the load-side of the frame, by a tension resistance, which may consist e.g. of a mechanical spring, a helical spring or another equivalent member. The tension resistance has been provided to inhibit the downward movement of the lever, and at the same time of the flap, so that the lever only moves after the hydraulic cylinder has moved the prongs in under the load to be handled, whereafter the same hydraulic cylinder presses the flap against the load.
In an embodiment of the invention, the redirecting means supported by the lower part of the frame consists of a linkage mechanism, i.e., of a first linkage arm pivotally attached to the piston rod of the hydraulic cylinder, the other end of this arm being pivotally contiguous with the frame, and of a second linkage arm pivotally attached to the piston rod and of which the other end is pivotally connected to be contiguous with the prongs.
In another embodiment of the invention, the redirecting means comprises an elastic, or flexible, redirecting member, of which the other end is connected with the prongs so that the vertical movement of the piston rod is by action of this redirecting member transformed to produce horizontal movement of the prongs.
For redirecting member, one may use e.g. a rod of some suitable elastic material, e.g. a rubber rod, which with the aid of suitable guides or guide members moves curvilinearly between the piston rod and the prongs. Chains, metal wires or equivalent members running in or over appropriate guides or guide members can also be contemplated.
The lifting device advantageously comprises a locking means enabling downward movement of the lever to be inhibited e.g. when the load which is being handled cannot tolerate the impact from the flap upon the load. The locking member may consist e.g. of a locking pin or equivalent member on the vertical frame, which is turned or pushed, or in another way positioned across the lever's path. The locking member may also be located on the transversal support, and it may in this case be, for instance, a hasp-like member, a hook or equivalent by means of which the lever is locked to stay at a given distance from the transversal support.
The lifting device of the invention has the advantage over prior art that it is possible therein to use comparatively long prongs and, thus, the device can handle comparatively big loads which have to be lifted, without incurring any such increase of the device's dimensions that they would impede its use and its managing in cramped lifting and loading premises.
In the following the invention is described in detail, referring to the drawing hereto attached, wherein

Fig. 1 presents a device according to the invention, and
Fig. 2 presents another device according to the invention.

The lifting device of Fig. 1 as well as that of Fig. 2 comprises a vertical frame 1, on the end of which a transversal support 2 has been rigidly mounted. On the lower end of the frame two side-by-side slides or guides 3 are provided, supporting side-by-side, horizontal prongs 4. Only one of the slides and only one prong are visible in the figure.
The transversal support 2 is substantially horizontal, yet slightly obliquely upward directed from the frame 1 up over the prongs 4. However, the support 2 also extendsbeyond the frame 1, constituting an extension 14 having on its end a pivot point 15, at which a lever 7 extending through or past the frame 1 is pivotally attached.
On the other end of the lever 7, i.e., on the end extending over the prongs 4 and over the load 11 which is being handled, belongs a flap mechanism 5, pivotally attached to this end of the lever 7 in such manner that the flap keeps substantially horizontal at all times owing to its proper weight. Furthermore, the end of the lever 7 adjacent to the flap 8 connects by a tension resistance 16, or by a spring, with the transversal support 2, above the end of the lever 7. On the transversal support 2 is provided a hoisting hook 12 sliding or moving on longitudinal guides thereof. The hoisting hook is furthermore connected to the end on the side of the extension 14 of the support by means of a tension member 13, e.g. a helical spring.
On the top end of the vertical frame 1 belongs a locking member 22, a cotter pin or equivalent member, which can be pushed across the path of the lever 7 to inhibit downward movement of the lever 7 from its upper position.
Close to the pivot point 15 of the lever 7, on the side of the frame 1 opposite from the load 11, a hydraulic cylinder 6 is pivotally attached to the underside of the lever 7, this cylinder being substantially vertical and parallel to the frame 1.
The structural designs presented in the foregoing are present in both embodiments presented, i.e., in the embodiments of Fig. 1 and Fig. 2, and they are indicated by identical reference numerals in both figures.
In Fig. 1 the piston rod 17 of the hydraulic cylinder 6 is connected to the prongs by a redirecting means 9. The redirecting means 9 consists of a first linkage arm 18, of which one end is pivotally attached to the end of the piston rod 17 and the other end is pivotally attached to the lower end of the frame 1, in the vicinity of the slide 3. The redirecting means 9 further comprises a second linkage arm 19, one end thereof pivotally attached to the piston rod 17 and the other end, to the end of the prongs 4. Hereby the redirecting means 9 transforms the substantially vertical movement of the piston rod 17 of the hydraulic cylinder 6 to become a substantially horizontal movement of the prongs 4.
In the embodiment of Fig. 2, the redirecting means 10 comprises an elastic and flexible redirecting member 20 attached to the end of the hydraulic cylinder's piston rod 17, this being a rubber rod travelling through or over curvilinear guides 21 and connected at its other end to the end of the prongs 4. Hereby the downward movement of the piston rod will push the rubber rod through the guides 21 and turn the other end of the rubber rod to be substantially horizontal. It is thus understood that the redirecting means 10 transforms the movement of the hydraulic cylinder, substantially vertical in direction, to produce horizontal movement of the prongs 4.
The lifting devices depicted in Figs 1 and 2 are operated as follows. In the position at rest, the prongs are in their rear position, and the flap 8 is in the upper position. Moreover, the draw hook 12 is pulled by the spring 13 to reside comparatively close to the frame 1. Now, for lifting a burden 11, the device is with a suitable hoisting means deposited to stand beside the burden 11. By making the hydraulic cylinder 6 retract the piston rod 17, the prongs 4 are caused to enter under the burden 11 which shall be lifted. Since the movement of the prongs 4 is substantially free of resistance, they will move easily in under the burden, while the tension resistance 16 prevents any downward movement of the lever 7.
Not until the prongs 4 have reached their forward position, as shown in the figures, does the force of the hydraulic cylinder 6 overcome the force of the tension resistance, and the lever 7 will then press the flap 8 against the burden 11. In this way the burden is held firmly in place throughout the lifting operation.
When the burden is lifted with a hoisting means, the lifting hook 12 moves along the transversal support 2, obliquely upward against the pull of the tension means 13, the length of sliding depending on the weight of the burden which is being lifted. The lifting hook is thus made to move in accordance with the burden's weight approximately so that the lifting device always maintains a substantially upright orientation while lifting is going on.
When the burden 11 is lowered by the lifting device, the hydraulic cylinder 6 first releases the flap 8 from over the burden 11, owing to the pull of the tension resistance 16. Only thereafter are the prongs 4 withdrawn from under the load, into their rear position, and the lifting means can be transported to the next point where lifting has to be done.
In the foregoing the invention has been described by way of example with the aid of the accompanying drawing, while different embodiments of the invention are feasible within the scope of the inventive idea delimited by the claims.

Claims

A lifting device for lifting and transporting goods, comprising
- a vertical frame (1), a transversal support (2) resting on the top end thereof,

- on the lower end of said frame, prongs (4) movable horizontally carried by slides (3) and which can be pushed in under the goods to be lifted,

- a flap mechanism (5) supported by the top end of the frame, for retaining from above the goods which is being lifted, and

- a hydraulic cylinder (6) for operating the prongs and the flap mechanism,
characterized in that

- the flap mechanism (5) comprises a lever (7) supported by the frame (1) or by the support (2) and carrying on one end a flap (8) steadying the load, and that

- the hydraulic cylinder (6) is substantially vertical and rests with its top end against the lever and with its lower end, against a redirecting means (9,10) communicating with the prongs (4), for moving the flap and the prongs by means of one hydraulic cylinder.
Lifting device according to claim 1, characterized in that the transversal support (2) extends mainly from the frame (1) over the load (11), the support comprising a lifting hook (12) for lifting the lifting device e.g. with a crane.
Lifting device according to claim 2, characterized in that the support (2) extends from the frame (1) obliquely upward over the load (11), the lifting hook (12) sliding along the support resisted by a tension means (13) in dependance of the weight of the load, when the lifting device is being lifted, so that the lifting device will remain substantially upright independent of its total weight.
Lifting device according to any one of claims 1-3, characterized in that the transversal support (2) extends from the frame (1) to the side opposite from the load (11), constituting an extension (14), to which the lever (7) is pivoted by one end.
Lifting device according to any one of claims 1-4, characterized in that the hydraulic cylinder (6) rests against the lever (7) at a point between the pivot point (15) of the lever and the extension (14) and the frame (1).
Lifting device according to any one of claims 1-5, characterized in that the lever (7) is by the part on the load-side (11) of the frame (1) connected to the transversal support (2) over a tension resistance (16) which inhibits the downward movement of the lever until the hydraulic cylinder (6) has moved the prongs (4) in under the load.
Lifting device according to any one of claims 1-6, characterized in that the redirecting means (9) comprises a first linkage arm (18) pivotally attached to the piston rod (17) of the hydraulic cylinder (6), its other end being pivoted to connect with the frame (1), and a second linkage arm (19) of which the other end is pivoted to connect with the prongs (4).
Lifting device according to any one of claims 1-6, characterized in that the redirecting means (10) comprises an elastic or flexible redirecting member (20) connected to the piston rod (17) for directing the substantially vertical movement of the piston rod to be transformed into substantially horizontal movement of the prongs (4).
Lifting device according to claim 1, characterized in that the redirecting means (10) comprises guides or guide members (21) along which the redirecting member (20) moves and turns or bends in controlled manner between the substantially vertical movement of the piston rod (17) and the substantially horizontal movement of the prongs (4).
Lifting device according to any one of claims 1-9, characterized in that the frame (1) comprises a locking member (22) for inhibition of the lever's (7) downward movement.