GB2044721A - Loading Lift for a Truck - Google Patents

Abstract

A loading lift, particularly for a truck, has a loading/unloading platform 10 which is pivotally connected about a horizontal axis 9 at the lower end of a carriage 2 so as to be capable of upward and downward turning movement about the axis, the carriage in turn being attached to the truck frame so as to be movable upwardly and downwardly relatively thereto. At least one point 14 at or adjacent to the free end 11 of the platform is connected through a chain or rod 13 to a point 12 adjacent to the upper end of the carriage and means 6, 7, 8 are connected to the carriage whereby automatically the free platform edge 11 in the operative position of the platform resting on the ground is situated lower than the horizontal pivot axis 9, as shown in broken lines, when the ground surface slopes downwardly away from the carriage 2 but automatically resumes its horizontal position when the platform is lifted. <IMAGE>

Description

SPECIFICATION Loading Lift for a Truck The invention relates to a loading lift, particularly for a truck, comprising a loadingunloading-platform which is connected pivotably upwardly and downwardly around a horizonal axis at the lower end of a carriage, which carriage is in turn connected upwardly and downwardly movable to the truck frame, in which at least one point at or adjacent to the free edge of the platform is connected through a chain or rod to a point near the upper end of the carriage.

Such loading lifts are generally known.

When the platform is lowered to the ground for loading or unloading, its free edge, which is beveled, must rest on the ground for permitting the passage of cattle, or wheeled containers or similar loads. The platform edge will not rest on the ground if the ground which supports the truck is inclined with respect to the horizontal in the direction downwardly from the back end of the truck, since the platform extends horizontally from the carriage. For it is that during lifting and lowering the platform must be horizontal since otherwise the load would slide off the platform.

Furthermore it sometimes occurs that when the ground extends horizontally and the platform rests thereon, when a truck is unloaded, since usually first the loads closest to the back of the truck are discharged, so that the center of gravity of the load in the truck shifts forwardly, the back end of the truck moves upwardly whereby likewise the free edge of the platform becomes spaced above the ground.

A different type of loading platform at the back of trucks is known, the so-called loading flap. This platform has a wedge-shaped cross-section, the thin end of which is at the free edge, so that the spacing between the ground and the truck floor, also on an inclined surface, always can be bridged by adjusting the correct pivot angle of the platform in that it is, as in the case of the loading lift, provided pivotablylaround a horizontal axis, in this case around a fixed point on the truck frame.

Pivoting here is effected by a piston-cylinderassembly, pivotably mounted to the platform and provided below the truck floor, said assembly engaging a point of the thick end of the platform situated closely below the horizontal pivot axis.

Because of the short lever arm of the pistoncyliner-assembly this requires a heavy construction, which is expensive, requires much maintenance work and nevertheless quickly wears.

This platform cannot be moved upwardly and downwardly, so that an intermediate floor above the truck floor cannot be served as is the case with a loading lift.

The invention aims at providing a loading lift not presenting the above mentioned disadvantages.

This is achieved according to the invention in that means are connected to the carriage whereby in the operative position of the platform resting on the ground, with inclined ground surface and in adaptation thereto, automatically, the free platform edge becomes situated lower than the horizontal pivot axis and the platform automatically reassumes its horizontal position when the platform is lifted.

Thereby an adaptation is obtained as well to an inclined ground surface as to a change of position of the truck, and to the horizontal position of the platform during lifting and lowering.

In a first embodiment according to the invention the means comprise a sliding sleeve adjacent to the lower end of the carriage, in which sleeve a pin is slidably arranged, one end of the pin being connected to the horizontal pivot shaft of the platform and the other end carrying an abutment cooperating with the sleeve, the sliding distance of the pin corresponding to the anticipated ground inclination.

In a second embodiment according to the invention, in which the movement of the carriage upwardly and downwardly is obtained by a piston-cylinder-assembly which is connected through a cable with the upper end of the carriage, the means comprise a lever, one end of which is rotatably provided in the carriage in a point outside the medial line of the carriage and the other end of which is rotatably connected to a point of the cable, the relative end of the platform chain or rod being connected to a point intermediate the ends of the lever.

The invention will be further illustrated below with reference to the drawing, which shows two embodiments of the loading lift according to the invention.

Figure 1 is a schematic side elevation of the first embodiment.

Figure 2 shows a schematic side elevation of the second embodiment, with a detail cross section in Figure 2a.

Both figures show two vertical posts of the frame of a truck upper structure, said posts lying one behind the other in a plane perpendicular to the plane of the drawing and are provided at the back or loading and unloading end of the truck.

Only the front post 1 of both posts is visible since the other lies exactly behind it. Said both posts are mutually connected at the lower and upper ends by a transverse beam (not shown). A carriage 2 is upwardly and downwardly movable between said vertical posts, said carriage being indicated by broken lines. The posts 1 may have a U-shaped cross-section whereby they constitute a guide for the side edges of and/or rollers 2a of the carriage.

The upper end of the carriage is connected in the embodiment shown through a cable 3 along a guide roller 4 connected to the upper transverse beam of the posts to a piston-cylinder-assembly 5 (only schematically shown) said assembly being connected to the truck frame. The carriage 2 is shown in the figures in its lower position.

In the embodiment of Figure 1 a sleeve 6 is secured at both sides of the carriage 2, as seen in back view, adjacent the lower end of said carriage. In each sleeve 6 a short rod 7 is provided slidable with clearance in the bore of the sleeve.

Said rod has at its upper end a head 8 having larger dimensions than the bore of the sleeve 6, so that said head serves as an abutment when the rod 7 is lowered relative to the sleeve 6, so that said rod cannot move further downwardly when the head 8 engages the upper surface of the sleeve 6. The lower end of the rod 7 carries the horizontal pivot shaft 9, mentioned above, which is pivotably connected to one end of a platform 10, constituting the loading platform of the truck.

The free end of the platform is beveled at 11 so that when the platform rests on the ground an adaptation is obtained to the ground surface, so that a continuously sloping edge for the loads is provided.

Each rod 7 may be connected to its own, short horizontal shaft 9, but said shafts also may constitute a continuous shaft connected to both rods 7 at both sides of the carriage.

A support 12 at the upper end of the carriage 2 is connected to one end of the chain 13, the other end of which is connected to a point 14 adjacent to the free end 11 of the platform.

Said embodiment operates as follows.

When the carriage 2 is lowered until the platform 10 contacts the ground, when the ground surface slopes downwardly from the back of the truck at the location of the carriage 2, first the end of the platform 10 at the position of the shaft or shafts 9 will contact the ground. Would the shaft 9 be fixedly connected to the carriage, then the free end 11 of the platform is in this position somewhat spaced from the ground, which presents difficulties when loading and unloading the truck. If the carriage 2 is further lowered after the end of the platform adjacent the shaft 9 has contacted the ground, then the rod 7 shifts with respect to the sleeve until the relative platform edge contacts the lower ends of the sleeves 6 at both sides of the carriage. Then the platform has an inclined position in which its complete underside contacts the ground.This position has been indicated by dotted lines 1 5. It will be clear that an inclined position of the platform at a greater angle than indicated at 1 5 is impossible, so that the sliding or shifting distance of the rod 7 must be chosen such that the maximum occurring inclinations may be handled.

If the inclination of the ground surface is smaller, then the rod 7 does not slide through its full slide distance.

If after loading or unloading the carriage must be lifted, e.g. in order to raise the platform to the height of an intermediate floor of the truck (not shown) or to bring the platform in the position in which it may be pivoted upwardly against the posts 1, for closing the loading space of the truck, the platform moves due to gravity with its edge downwardly at the position of the sleeves 6 until the heads 8 rest against the upper end of the sleeves. Thereby the platform has again reached a horizontal position so that a load, if resting on the platform, will not slide off this platform. The movement in adaptation to the inclined ground surface or back to the horizontal position respectively are permitted in that the free end 11 may pivot around the point in which the chain 13 is fixed to the support 12.

In the embodiment of Figure 2 a short strip 1 6 has been provided at the lower end of the carriage 2, at least at both sides thereof, as seen in back view of the carriage, said strip extening obliquely towards the pivot shaft or shafts 9 for the pivotal connection of the end of the platform 1 0, situated in front of the carriage 2.

A lever 1 8 is pivotably connected at one end to the cable 3 of the piston-cylinder-assembly 5 and is rotatable at its other end around a shaft 19 which is journalled in a support 20 (Fig. 2a) and connectd to the upper end of the carriage 2. Such lever with support is provided at both sides of the carriage, as seen in back view. One end of the chain 21, corresponding to the chain 13 according to Fig. 1 is connected to a point substantially intermediate the ends of the lever 18, while the other end of the chain 21, in like manner as in the first embodiment, is connected to a point 14 adjacent to the beveled free end 11 of the platform. The lever 1 8 engages in its upper position as shown an abutment 1 7 on the support 20.

The operation is as follows that the platform 10 may adapt itself to a sloping ground surface by pivoting around the shaft or shafts 9 andby the lowering of the point 14 of the platform in that the lever 18 and thereby the other end of the chain 21 may move downwardly from the upper position towards the lower position, both as shown in Fig. 2. Therein one end of the lever 1 8 pivots around the point 19 and the other end moves together with the cable of the pistoncylinder-assembly downwardly when said cable is paid out by said assembly. When the platform lowers it may adapt itself to a sloping ground surface through said lever and if, later on, the platform is again lifted, first the lever returns to its upper position against the abutment 1 7, whereby the end 11 of the platform is raised and the platform again resumes its horizontal position prior to the upward movement of the carriage.

Claims (5)

Claims

1. A loading lift, particularly for a truck, comprising a loading-unloading-platform which is upwardly and downwardly pivotably connected around a horizontal axis at the lower end of a carriage, said carriage in turn being provided to the truck frame upwardly and downwardly movable, in which at least one point at or adjacent to the free end of the platform is connected through a chain or rod to a point adjacent to the upper end of the carriage, characterized in that means are connected to the carriage whereby automatically the free platform edge in the operative position of the platform resting on the ground, this ground having a sloping ground surface, is situated lower than the horizontal pivot axis, and automatically resumes its horizontal position when the platform is lifted.

2. A loading lift according to claim 1, characterized in that the means comprise a sleeve (6) adjacent the lower end of the carriage (2), a pin (7) being slidably received in said sleeve, one end of the pin being connected to the horizontal pivot shaft (9) of the platform (10) and the other end of the pin carrying an abutment (8) cooperating with the sleeve, the sliding distance of the pin (7) corresponding to the anticipated ground inclination.

3. A loading lift according to claim 1, in which the lifting and lowering movement of the carriage is obtained by a piston-cylinder-assembly, which through a cable is connected to the upper end of the carriage, characterized in that the means comprise a lever (18), on end (19) of which is rotatably provided on the carriage (2) in a point outside the medial line of the carriage, and the other end of the lever being rotatably connected to a point of the cable (3), the relative end of the platform chain (21) or rod being connected with a point intermediate the ends of the lever (18).

4. A loading lift, particularly for a truck, having its parts constructed, arranged and adpated to operate substantially as herein described with reference to Figure 1 of the accompanying drawings.

5. A loading lift, particularly for a truck, having its parts constructed, arranged and adapted to operate substantially as herein described with reference to Figures 2 and 2a of the accompanying drawings.