HOISTING DEVICE

Abstract: Hoisting device for the lifting of a vehicle or similar and comprising a rectangular supporting framework (2), a lifting beam (10), between which a hoisting jack (8) is placed. In order to maintain the lifting beam (10) in parallel arrangement with the supporting framework (2), there is a pair of pivotable fork elements (14, 15) extending between the supporting frame work (2) and lifting beam (10), and these elements are in communication with each other through force transferring means (16, 17) causing the fork elements (14, 15) to pivot synchronously but in opposite directions in a plane parallel with the longitudinal axes of the rectangular supporting framework (2).

Description: HOISTING DEVICE The present invention concerns hoisting devices, and in particular a so called free wheel hoisting device. Such free wheel hoisting devices are especially used for the hoisting of vehicles in connection with repairs, trouble shooting, inspection and similar. With their help it is possible to hoist a vehicle at least at one wheel axle in such a way, that the wheels at the axle ends at the same time can rotate freely. This type of free wheel hoisting devices is commonly used in auto inspection facilities, where vehicles are hoisted for the examination of the state of the wheel suspension, steering mechanisms, wheel bearings and other important parts for safe road operation. It is important that the free wheel hoisting devices function quickly and safely, whatever their application field may be. This safety involves the assurance that the hoisting device maintains the elevated vehicle or similar in a steady, essentially horisontal position without any risk for the vehicle to topple at either side. Previously known free wheel hoisting devices disclose a rather complicated structure, which both is expensive to produce and tends to malfunction. v The purpose of the present invention is to eliminate the above problems. This objective is achieved by a free wheel hoisting device according to the claims, in which what is charac¬ teristic of the invention also becomes evident. The invention will be described more in detai l in the following, with reference to the accompanying drawings, wherein: fig. 1 is a perspective side view of a free wheel hoisting device according to the invention, f ig. 2 is a side view of a free wheel hoi sting device 2 according to the invention, in a lowered position, fig. 3 i s a side view according to fig. 2 showing the free wheel hoisting device in an elevated position, and f ig. 4 i s a top view of the free wheel hoi sting device according to figs. 2 and 3. The free wheel hoisting device 1 , which is shown in fig. 1 , comprises a supporting framework 2 in the form of two parallel arranged square bars 3 , 4 , in which suspension elements 5 , 6 are displaceably arranged. Thus , s e en f rom above the supporting framework 2 forms a rectangle, the length of which is adjustable dependent on the suspension. The suspension elements 5 , 6 are supposed to bear on to the edges of a lubricating or inspection pit, where there are guide rails (not shown) , on which rails rolers 7 run, which are in an unloadable way attached to the suspension elements 5, 6. Approximately in the mid- length of the parallel arranged square bars 3 , 4, there is provided a jack 8 and this jack, which in the shown embodiment is hydraulic, is driven by a hydraulic power supply 9 for the raising and lowering. In parallel with and ^_bove the supporting framework 2 there is a lifting beam 10, which is rais ed and lowered by means of the jack 8 , on the lifting beam 10 there are two extension elements 11 , 12 displaceably mounted and the extension elements 11, 12 have at there extremities holder fittings 13, for the sake of adapting to appropriate places on the axle, or similar, to be raised. When hoisting the lifting beam 10 , onto which a vehicle or other kind of load is bearing, the load may turn out to bear unequally on the two opposing sides of the jack 8, which could result in a slight unbalance of the lifting beam 10 and, thus, the risk for the load to slide off. There is always a risk for this to happen, no matter the type of jack or hoisting device. In order to prevent this to happen, there is arranged an arm system according to the invention, being of the following structure: There are two fork elements 14, 15 pivotably attached to the supporting framework 2, one on each side of the jack 8. They are connected by means of a pair of cog wheel segments 16, 17 in a gear engagement, which, when one of the fork elements 14, 15 is being pivoted, cause the other segment to follow to the same extent. The portions of the fork elements 14, 15 that are distal to the cog wheel segments 16, 17, are equipped with trunnions 18, 19 extending in longitudinal grooves 20, 21, which are parallel with the plane of the lifting beam 10 and which are formed in projections 22 which are welded at the underside of the lifting beam 10. When hoisting the lifting beam 10 from the position shown in fig. 2 to the position shown in fig. 3, the lifting forks 14, 15 will be pulled upwardly and due to the cooperation of the cog wheel segments 16, 17, they will be pivoted to the same extent. This means that the lifting beam 10 will be hoisted in parallel with the supporting framework. Should the load on one side of the jack 8 be bigger than on the other side, a load unbalance of the lifting beam 10 will not occur, since a downward force on onr of the fork elements 14, 15 leads to a corresponding downward force on the other one, due to the force transfer by the cog wheel segments 16, 17. To facilitate the pivot motion of the fork elements 14, 15 and to stabilize them, there is an arm 23 pivotably attached to one arm of a fork element 15, as well as to a connection piece 24 attached to the lifting beam 10. The arm 23, thus, serves to help one of the fork elements 15 to pivot and through the cog wheel segments 16, 17 to pivot the other fork element 14 as well, while the transfer of the load unbalance of the lifting beam 10 occurs through the projections 22 and the trunnions 18, 19, which is then counteracted by the force transfer of the cog wheel segments 16, 17. As is evident from the above, the present invention provides both a simple and safe hoisting device, eliminating the initially posed problems with the known devices. The invention can, per se, be varied regarding details, but such variations are supposed to be encompassed by the scope of the invention, as they are defined in the appended patent claims.

Claims: 5 CLAIMS 1. A hoisting device, particularly for hoisting vehicles, comprising a supporting framework (2) of an essentially rectangular configuration, a lifting beam (10), a hoisting jack (8), and a couple of pivotable arms (14, 15), which stabilize the lifting beam (10) relative to the supporting framework (2), c h a r a c t e r i z e d in that the hoisting jack (8) is arranged to function directly between the supporting framework (2) and the lifting beam (10), that a force transferring means (16, 17), which transfers the pivot motion of one of the arms (14, 15) and of one direction into a synchronous pivot motion of the opposite direction for the other arm (14, 15), whereby the pivot motions occur in a plane that is parallel with the longitudinal axes of the rectangular supporting framework (2). 2. The hoisting device according to claim 1, c h a r a c ¬ t e r i z e d in that the force transferring means comprise cog wheel segments (16, 17) in a gear engagement, one of the segments being engaged at the end of corresponding arm (14, 15), which is pivotably attached to the supporting framework (2). 3. A hoisting device according to claim 1 or 2, c h a r a c- t e r i z e d in that the hoisting jack comprises a hydraulic power supply (8). 4. A hoisting device according to previous claims, c h a r a c t e r i z e d by a supporting arm (23) which is pivotably attached to one of the arms (14, 15), as well as to the lifting beam (10).

Inventors: JOHANSSON SVEN-ERIC, JOHANSSON, SVEN-ERIC
Applicants: HYCO HYDRAULIC AB
Application year: 1986
Main classification: B66F7
IPC codes: B66F7