MOVABLE LOADING BRIDGE

Abstract: The invention concerns a loading bridge for making a connection between a loading platform and a vehicle, wherein the height of the bridge is variable at the side of the vehicle to allow for vehicles with different heights. A gas-operated driving mechanism is disclosed of which the costs are considerably less than prior art hydraulic driving mechanisms. Further a mechanism is disclosed for automatically controlling the movements of a lid connected with the loading bridge.

Description: The present invention relates to a loading bridge for making a connection between a loading platform and a vehicle, in which the loading bridge is hingedly connected to the loading platform, and of which the height at the side of the vehicle is variable and comprising a mechanism for raising and lowering said bridge. Such a loading bridge is known from US-A-4293969. This prior art loading bridge is driven for vertical movement through a hydraulic apparatus. Herein a hydraulic cylinder is provided between a fixed point and a point of the bridge, so that the loading bridge can be moved in the vertical direction and can even be locked. Also loading bridges are known, which are operated by hand, and which rest at the movable side on the loading floor of the vehicle. All these known loading bridges have a number of disadvantages; manually operated loading bridges can only be applied until a certain weight, as otherwise they become too heavy and cannot be moved by human power. Big loading bridges, which often comprise a hydraulic drive, have the disadvantage, that these hydraulic apparatus are rather costly, so that the price of such loading bridges is substantial. The same disadvantage does also exist when the loading bridge is driven by an electromotor and a rack and pinion. The present invention tries to provide such a loading bridge, which can be provided with a driving mechanism for relatively modest cost, despite substantial dimensions. This aim is achieved in that said mechanism for raising and lowering said bridge is formed by a flexible body of which the volume increases, when a gas is supplied to it and of which the volume decreases, when gas is released from it according to the features of claim 1. As the price of such a flexible body is modest, and the filling thereof requires only equipment, of which the price is low, a raising mechanism for such a bridge is provided, which can be manufactured against modest costs. Thus the cost of such a loading bridge are decreased considerably. In this respect the remark is made, that the bridge only has to be lifted in its unloaded condition; hence there is no need for substantial power, so that relatively light and simple pneumatic apparatus can satisfy. EP-A-0001316 discloses a holder for packaging articles, in which the articles are located on a platform and in which the platform can be lifted by means of a bellows. The weight of such articles is, however, low, so that this device cannot be compared with the loading brigde according to the present invention. The use of bellows within lifting devices is further known from the prospectus "Mecmans bälg cylinder serie 1900 för pneumatic". Subsequently the present invention will be elucidated with the help of the accompanying drawings, wherein: fig. 1: is a schematic perspective view of a closed loading platform comprising a loading bridge; fig. 2: is a schematic exploded view of a first embodiment of a loading bridge according to the present invention; fig. 3: is a schematic cross-sectional view of the first embodiment of a loading bridge according to the present invention; fig. 4: is a schematic perspective view of a second embodiment of a loading bridge according to the present invention; fig. 5: is a cross-sectional view of an alternative embodiment for the controlling mechanism of the lid of the loading bridge according to the present invention; and fig. 6: is a perspective view partially broken away of a third embodiment of the present invention; and fig. 7: is a cross-sectional view, partially as a side view of the embodiment depicted in fig. 6. The loading platform 1 depicted in fig. 1 comprises a pit 2, in which a loading bridge 3 has been provided. In the present case the loading platform 1 is covered, i.e. that a wall 4 has been provided, wherein a roll down shutter 5 has been provided at the location of the loading bridge 3. A vehicle to be loaded, for instance a lorry, drives with its rear side as close as possible against the loading platform 1, wherein the rear side of the lorry hits the buffers 6. Then the roll down shutter 5 is moved upwardly, and the height of the loading bridge 3 is adapted to the height of the rear side of the lorry, so that this can be loaded easily. It is convenient to drive into the lorry from the loading platform with for instance fork lifts. Fig. 2 shows an exploded view of such a loading bridge according to the present invention. The loading bridge comprises a housing, which is composed of two fixed sides 7, which have been folded zigzag-wise, and also a rear wall 8. The rear wall comprises reinforcement pieces 9, which are mutually connected through bars 10. When providing such a loading bridge in a loading platform, the loading bridge is located as a whole on the right spot, after which the loading platform is formed in concrete. Thus the sides 7, the rear wall 8, the reinforcement pieces 9 and the bars 10 function as a lost formwork. Into the housing thus obtained a base 11 is provided, which comprises a substantially horizontal part 12 and a part 13 extending obliquely downward to the front. Also the bottom comprises a front wall 14 extending obliquely upwardly. The loading bridge per se comprises a movable plate 15, which is manufactured of steel or aluminium; and to the lower side thereof reinforcement ribs 16 have been welded. Further a round rod 17 has been welded to the under side of the plate 15, which rests in an array of substantially L-shaped hooks welded against the back wall 8. Finally a filling piece 19 has been welded against the lower side of the plate 15, which filling piece 19 can be manufactured from a steel box or may be composed of rather light material, like tempex. At the lower side of the plate 15 a lid 21 has been hingedly connected by means of hinges 20. In the space between the filling piece 19 and the oblique part 13 of the bottom, a flexible bag or bellows 22 has been provided, which may be manufactured from for instance polyethylene. The form of this bag is such that it fits in the space thus provided. Further this bag comprises a connection 23, which fits into a whole 24 provided in the bottom. Through this connection a gas, for instance air can be supplied, and which can fill the bag 22, so that the bridge is raised thereby. The cross-sectional view shown in fig. 3 shows how the bag 22 is locked up in the space between the oblique part 13 of the bottom and the filling piece 19. The bag may be connected with the lower side of the filling piece by for instance adhesive or buttons. Further it is shown how a ventilator 26 can blow up the bag 22 through a tube 25 against the spring pressure of a one-way valve 27. Further a valve 28 with pressure dependent action has been provided in the tube, which lets a part of the air flow out when the pressure in the bag becomes too high, so that the loading bridge under a changing load, for instance the driving on and off a fork lifter, does not suddenly jump upwardly. Instead of a ventilator, a compressor with a venturi can be used. Further in the drawing it is shown how the loading bridge 29 can be moved from a lorry 30 until under the space under the apparatus, so that it does not interfere the loading and unloading. To avoid wear of the bag during the movement, the front wall 14 thereof is formed such, that the bag wall rolls off or on, when moving the loading bridge. The same feature has been applied with the side walls; the wall of the bag rolls as a membrane on or off against the side wall 19. Besides these side walls 19 serve to protect the bag 22 in the highest position of the loading bridge. Further it is shown in this figure how the lid 21, which is connected with the bridge 15 by means of a hinge 20, is provided of a rod mechanism, that provides for the fact, that the lid 21 is usually in its inward position, whereas when reaching the highest position of the loading bridge the rod mechanism forces the lid upwardly, so that this is in the position shown with drawn lines in the figure, after which the loading bridge may descend until the position, in which this connects on the loading floor of the lorry 30, and rests on the frame of the lorry or on the loading floor thereof. The lid 21 is kept in this position by a cam 32 welded thereon by a folded rod 33, which is connected with the loading bridge 15 by means of a hinge 34, and a rod 35 connected hingedly with the other side thereof, which rod comprises a thickening 36 at its lower side. Further this rod 35 extends through an aperture in the front plate 14. When reaching the upper position of the loading bridge, the thickening 36 in the rod 35 exerts a force to the folded rod 33, so that this rod moves the lid 21 to its extended position. This position is maintained by the cam 32 when moving downwardly. In fig. 4 another embodiment of the loading bridge is shown, in which another plate 15 of the loading bridge, a network of thin metal strips 36 have been provided, so that a honeycomb-like structure develops. This results in a lighter construction of the reinforcement of the loading bridge, which may considerably reduce the costs thereof. This construction is only allowed because the forces of the loading bridge are borne by the whole underside thereof, so that the construction for the concentrating of the forces to one point, which was necessary when using a hydraulic drive, is superfluous. This has of course a very favorable outworking on the price. Further this loading bridge comprises a rod system 37 and a spring 38, which also provides that during the descending only of the loading bridge the lid 21 is in its extended position. Further the bag can be made so large, that it pushes directly against the lower side of the bridge and makes the filling piece superfluous. This is further elucidated with the help of fig. 5. When moving upwardly, the compression spring 38 will urge the rod system 37 outwardly, which is avoided by the cam 39. When the bridge has reached its highest position, the chain 40 will pull the rod system 37 downwardly, so that the spring 38 urges the rod system 37 downwardly and outwardly, so that the lid 21 is urged to its extended position. During the following the descending of the bridge, the rod system 37 will be received by a top 141, which urges the rod system and the spring 38 back to their original positions. Of course a lot of other possibilities is present for the controlling of the lid 21. In the embodiment of the loading bridge depicted in fig. 6 and 7 the bag 22 has been replaced by a bellows 41. Besides the construction of this embodiment of the loading bridge 3 is substantially equal to the embodiment depicted in fig. 1-3. The present embodiment is different, because no housing, in which the bag 22 is enclosed, as there is no question anymore of a bag. The only reason for nevertheless applying a full housing is the use thereof as lost formwork. This is of course also possible together with the application of a bellows. Instead thereof a frame 43 is used, of which the plate 15 of the loading bridge is provided hingedly, in a way substantially as in the first embodiment. For bearing the load of the frame on the base two brackets 44 have been provided. Further in this embodiment the plate 15 is reinforced by spars 42. The bellows rests with its bottom on the horizontal part of the bracket 44, whereas the top thereof is connected with a plate 45, being connected with the two middle spars 42. Further the side wall of loading bridge is composed of plates 19, which avoid, that part of the body become squeezed between the frame and the bridge. Besides the construction of the bellows is depicted in fig. 7. The bellows 41 comprises a bottom plate 46, which is connected on the horizontal part 44 through an intermediate piece 47. The bellows per se, which is composed of a flexible bag 48, for instance made of rubber or of plastic, is connected with the base plate 46 and a top plate 49. To avoid extension of the bag 48 in the horizontal direction two rings 50 have been provided. Through a pipe 51, extending through the intermediate piece 47 and the base plate 46 a gas, for instance air can be supplied to make the volume of the bag 48 increase. In view of the supply of air or a gas referred is to the embodiment described with the help of fig. 3. Besides several features of the different embodiments can be mutually combined.

Claims: Loading bridge (3) for making a connection between a loading platform (1) and a vehicle (30), and comprising a plate (15) which is hingedly connected to the loading platform (1), and of which the height at the side of the vehicle (30) is variable and comprising a mechanism for raising and lowering said plate (15), characterized in that said mechanism for raising and lowering said bridge is formed by a flexible body (22;25,27;41,51) of which the volume increases, when air is supplied to it and of which the volume decreases, when the air is released from it and which is dimensioned for lifting only the plate (15) unloaded, that the loading bridge comprises a lid (21) hingedly connected to the front of the plate (15), and that the plate (15) rests at its front end on the vehicle (30) through the lid (21) during loading. Loading bridge according to claim 1, characterized in that the body is a bag (22) made by polyethylene or PVC, covering substantially the whole underside of the loading bridge (3). Loading bridge according to one of the preceding claims, characterized in that the bridge comprises a skirt (19) extending downward from the front of the plate (15), so that the front (14) of the bag (22) peels off on the front of the housing (13,14), that the bridge comprises skirts (19) extending downward from both sides, so that the sides of the bag peel off the sides of the housing (13,14). Loading bridge according to claim 1, characterized in that the flexible body comprises a bellows (41) with a rigid bottom (47) and a rigid top (45), the top (45) being connected with the bridge (15,3) and the bottom being fixed to the base (44). Loading bridge according to claim 4, characterized in that the bellows (41) is an air spring as generally applied in vehicle engineering. Loading bridge according to one of the preceding claims, characterized in that the loading bridge (3) is imbedded in the loading platform (1) and that the housing (7,8,9,10), in which the bag (22) is provided, is a part of the form work of the loading platform (1). Loading bridge according to one of the claims 1 to 6, characterized in that the lid (21) comprises a controlling mechanism (37,38,39,40) controlling the movements thereof such, that the lid (21) is hinged upwardly during the upper movement of the plate (3).

Inventors: MEGENS, JOHANNES HENDRIKUS
Applicants: ROLFLEX OOST NEDERLAND B.V.
Application year: 1990
Main classification: B65G69
IPC codes: B65G69