WO1986004307A1

WO1986004307A1 - Loading and unloading mechanism

Info

Publication number: WO1986004307A1
Application number: PCT/GB1986/000049
Authority: WO
Inventors: Reijo Juhani Raisio; Markku Suomi
Original assignee: Multilift Limited
Priority date: 1985-01-29
Filing date: 1986-01-27
Publication date: 1986-07-31
Also published as: EP0246232A1; GB8502151D0; GB2170184A

Abstract

A mechanism for loading and unloading a container or platform over the rear of the vehicle includes an arm (120) (herein called a hook arm) at one end of which is disposed a hook or gripping member by which the mechanism can be connected to a container or platform. The arm (120) forms part of a linkage which is operable by sequential extension of a first ram (130) and a second ram (140). The arrangement of the linkage is such that sequential operation of the rams shifts the hook between a first or loaded position in which the linkage is located wholly beneath the container or platform and a second or 'pick-up' position in which the hook or gripping member is disposed substantially at ground level at the rear of the vehicle. Such a mechanism requires less space above the vehicle, and is foldable to lie flat beneath a loaded container.

Description

LOADING AND UNLOADING MECHANISM

This invention relates to a mechanism for loading and unloading a container or platform over the rear of a vehicle.

Such mechanisms are known. An early design is one involving a sliding movement between one arm or frame and another, and then a pivoting movement, see for example U.K. Patent Specifications Nos. 1,327,928; 1,371,811; 1,371,812; 1,371,813 ; 1,416,864 and 1,551,936. Arrangements of this kind are mechanically complex and therefore tend to be expensive. Another known design involves a pivoting L-shaped arm, moving in a substantially vertical plane and requiring considerable space above the vehicle, see for example U.K. Patent Specifications Nos. 1,540,611; 2,018,716; 2,033 ,346 and 2,092,993. It would be desirable if there was available a lifting mechanism which operated in such a way as not to require substantial space above the vehicle.

According to the present invention, there is provided a mechanism for loading and unloading a container or platform over the rear of a vehicle, which comprises a particularly compact and efficient linkage arrrangement. Each of the links may take the form of an arm or a frame, and to improve load-bearing capacity, certain links may be constituted by a pair of parallel arms. The linkage is operated by fluid pressure piston- cylinder devices, herein called 'rams' for brevity; in some cases a pair or more than two rams may be arranged in parallel. In the present description of the linkage, purely for brevity and clarity of language, the singular terms ram and frame will be used, it being understood that these terms are intended to encompass more than one ram or frame arranged in parallel and that the word frame is intended to include, where the context permits, a simple link, bar or arm.

According to one aspect of the invention, a mechanism for loading and unloading a container or platform over the rear of the vehicle includes an arm (herein called a hook arm) at one end of which is disposed a hook or gripping member by which the mechanism can be connected to a container or platform, the arm forming part of a linkage which is operable by sequential extension of a first ram and a second ram, the arrangement of the linkage being such that sequential operation of the rams shifts the hook between a first or loaded position in which the linkage is located wholly beneath the container or platform and a second or 'pick-up' position in which the hook or gripping member is disposed substantially at ground level at the rear of the vehicle.

In the present text the first and second rams are referred to as the hook arm ram and the main ram respectively, and the word "hook" is used to signify any gripping,- grasping, hooking or like means by which a container or platform to be loaded can be connected to an arm or frame.

The mechanism in accordance with another aspect of the present invention includes a first frame which is pivotally connected to a hook arm in such a way that the hook arm can be caused to describe a movement through substantially 270° in a vertical plane under the action of two or more rams.

With such an arrangement, less space above a vehicle than needed with prior designs is required when loading or unloading a container or platform, and in the loaded position of the container (or platform) the mechanism is located substantially wholly beneath the container.

The preferred arrangement includes a number of sub-links, each pivotally connected to various parts of the mechanism. These sub-links serve (speaking in general terms) to convert the direction of the thrust or pulling force of the ram to a desired direction to achieve a desired pivoting of a frame (i.e. a link of the linkage) so as to move the hook arm in a desired manner.

According to a preferred embodiment of the invention, the frame has one of its ends pivotally connected to the chassis and its other end pivotally connected to a sub-link herein called a second sub-link which in turn is pivotally connected to a first sub-link, the first sub-link serving to transmit a force applied by the hook arm ram to cause a pivoting movement of the hook arm.

Also according to a preferred embodiment of the invention, a sub- link herein called a fourth sub-link is pivotally connected to the frame near the end of the frame which is connected to the chassis, and the fourth sub- link is pivotally connected to a third sub-link, the third and fourth sub-links serving to locate one end of the main ram in such a position that its extension or contraction causes a pivoting movement of the frame about its pivotal connection to the chassis.

The invention will be better understood from the following non- limiting description of an example thereof, given with reference to the accompanying drawings in which:-

Figure 1 is a side elevation of one example of a loading and unloading mechanism in accordance with the invention;

Figure 2 is a plan view corresponding to Figure 1;

Figure 3 is an end elevation view corresponding to Figure 1 but omitting the end rollers which are seen in Figure 1;

Figure 4 is an end elevation view of the mechanism of Figure 1 but showing it in its position at the start of a pick-up or loading movement; and

Figure 5 is a side view corresponding to Figures 1 and 4 but showing the mechanism in the course of motion from a "lying flat" or loaded position to the unloaded position of Figure 4.

In the Figures of the drawings, like parts are denoted by like reference numerals.

The illustrated loading and unloading mechanism is intended for mounting upon a vehicle chassis. Two longitudinal beams are shown at 100; these beams may form part of the loading and unloading mechanism or alternatively these beams may be the fore and aft chassis beams of the vehicle. The loading and unloading mechanism is secured to the beams 100. A guide roller 102 is mounted at the outer side of each of the rear ends of the beams 100. The two rollers 102 may be mounted on a separate cross- frame (not shown) which is secured either to the longitudinal beams 100 of the loading and unloading mechanism or to a suitable anchorage on the vehicle. As is seen best in Figures 1 and 4, a locking arrangement 104 is provided, having a locking tongue 106 which in use serves to maintain a cross-bar on the underside of the container or platform within a recess 108 of the locking arrangement.

The illustrated loading and unloading mechanism includes the following principal parts, namely a frame 110, a hook arm 120, a main ram 130, and a hook arm ram 140. The system also includes four sub-links, herein referred to as first, second, third and fourth sub-links, which are utilized to pivotally connect the principal parts mentioned above in such a way as to achieve, in use, the desired movement of the hook 122 at the end of the hook arm 120 from its "loaded" position as seen in Figure 1 to its "unloaded" position as seen in Figure 4. The path of movement of the hook 122 is indicated by the connected curves AB, BC in Figure 1. The hook arm 120 has laterally extending support bars or "wings" 127, 129, which in the "folded flat" loaded condition of the linkage rest on the beams 100 and assist in supporting the weight of a loaded container or platform.

Referring now more particularly to Figures 4 and 5, the frame 110 is pivoted to the chassis for rotation about a substantially horizontal axis at a pivot 10, and a third sub-link SL3 is pivoted to the chassis by a pivot 24. To avoid unnecessary repetition, it is to be understood that the pivot points of the linkage referred to in this description are in relation to pivoting movement about a substantially horizontal axis, assuming the plane of movement of the hook arm to be in a substantially vertical plane. Also connected to the chassis is the hook arm ram 140, this pivot being indicated at 32.

As stated, the hook arm 120 carries a hook 22, and at its other end it has two pivotal connections. The first of these is a pivotal connection 12 between the frame 110 and the hook arm 120, and the second is a pivotal connection 14 between the hook arm 120 and a first sub-link SL1. The first sub-link SL1 has its other end connected by a pivot 18 to the hook arm ram 140, and there is a pivot 16 intermediate its ends connecting it to a second sub-link SL2. The other end of the second sub-link SL2 is pivotally connected at 20 to the frame 110. Turning now to the other end of the frame 110, as best seen at the left hand end of Figure 4 and at the right hand end of Figure 5, the frame 110 is connected by a pivot 30 to a fourth sub-link SL4, whose other end is connected by a pivot 26 to the third sub-link SL3. The pivot connection- 26 on the third sub-link is located intermediate its ends. One end of the third sub-link SL3 is connected by a pivot 24 to the chassis, and the other end of the third sub-link is connected by a pivot 28 to one end of the main ram 130. The other end of the main ram is connected by a pivot 22 to the frame 110. The second sub-link SL2 has one end pivotally connected by pivot 20 to the frame 110 and its other end pivotally connected by the pivot 16 to a first sub-link SL1.

Operation of the linkage will now be described.

Starting from the position illustrated in Figure 1, that is to say the "loaded" position in which the linkage is substantially flat and horizontal and is located substantially wholly beneath the container or platform which has been loaded on the vehicle, the first motion is an arcuate motion of the hook 122 from position A to position B, effected by extension of the hook arm ram 140. This motion extends through an arc of around 130-140°. Thereafter, by means of an extension of the main ram 130, the frame 110 is pivoted through substantially 180° in a clockwise direction from the position illustrated in Figure 5 to the position illustrated in Figure 4. At the end of its clockwise movement, the frame 110 is located just above the roller 102. In this position, the hook 122 is in the position indicated C, that is to say, it is in the pick-up position; the frame 110 is approximately horizontal, and the angle between the frame 110 and the hook arm 120 is approximately 110° to 120°. During the movement of the hook arm 120 from its Figure 5 to its Figure 4 position, the sub-links SL1 and SL2 pivot around the connection 20 between SL2 and the frame 110, and the sub- link SL1 pivots relative to sub-link SL2. The effect of this pivoting is to bring the hook arm 120 into a downwardly-extending position at the end of the movement of the main ram. Described in another way, at the end of the movement of the hook arm ram, i.e. in the Figure 5 position, the hook arm 120 has been moved through about 130° to 140°, e.g. about 135°, and the angle between the hook arm 120 and the frame 110 is about 50° to 40°, e.g. 45°. Due to the multiple pivot connections achieved by using the sub- links described, this angle is increased to about 110° to 120° during the extension movement of the main ram 130 which swings the frame 110 around its connection with the beams 100, to take up the Figure 4 position. Then the hook arm can be pivoted the necessary short distance e.g. by extending the hook arm ram 140 a little further for the hook to engage a suitable hook bar provided on the container or platform to be loaded. The position of a latch member 125, Figure 4, is adjusted as necessary to maintain a hook bar within the recess of the hook 122, so ensuring security of attachment between the container or platform and the hook arm 120.

It will be seen that the linkage system disclosed is effective to achieve an unloading movement ABC and a loading movement CBA while still requiring only limited head-room. The highest point of the hook 122 is that indicated at D in Figure 1, and it will be seen that the mechanism according to the particular disclosure herein requires far less vertical space than would be required, for comparable size equipment, by any of the linkages disclosed in the prior art patents referred to at the beginning of this specification. Moreover, the linkage system illustrated herein has another important advantage, namely that it does not require extra space to be left behind the vehicle cab to accommodate essential parts of the linkage system. So that this point can be more fully understood, brief reference will be made to British Patent 2,033 ,346 from which it is seen in Figure 1 that the front end of the container 2 has to be rearwardly spaced of the rear end of the cab of the vehicle, in order to accommodate the arm 10 and the ram 14 and associated parts. Likewise, in British Patent 1,540,611, space has to be allowed for the arm 18 behind the vehicle cab, as can be seen by reference to Figures 1 and 2. As can be seen from Figures 1 and 2 of British Patent 1,327,928, space must be left behind the vehicle cab to accommodate the arm 3. These arrangements are in contrast to, and are believed inferior to, the presently described arrangement in which substantially the whole of the lifting mechanism is located below the container so that no extra space between cab and container is needed.

A mechanism which has a low maximum height is important especially in the case of military use of a lifting mechanism, as it makes possible the transportation of a vehicle in an aeroplane. The mechanism particularly described herein has the advantage that it includes only two principal frame members,' namely the frame 110 and the hook arm 120, and only two hydraulic circuits, namely that of the main ram 130 and that of the hook arm ram 140. Moreover, these two circuits operate sequentially, and so the hydraulic control system is easy to design, is reliable, is of low cost, and requires less maintenance than more complex systems. To the best of Applicant's knowledge and belief, this arrangement is unique in that it is the first lifting mechanism for use on a vehicle which has no part whatsoever which extends above the top of a loaded container or the top of the load on a flat platform. The mechanism particularly disclosed herein can be readily attached to most types of vehicle. It requires only one region where fixing to the chassis is necessary, that is to say the fixing points to the vehicle chassis are the pivots 10, 24 and 32, all of which are located in the same region. A mechanism according to the invention can have the frame 110, the third sub-link SL3, and the hook arm ram 140 connected to a plate structure assembly which is itself connected to the chassis, and all the remaining parts and pivots do not require any connection to the vehicle chassis.

The provision of the sub-links SL1 and 2 between the frame 110 and the hook arm 120, and the provision of the sub-links SL3 and SL4 between the frame 110 and the beams 100 permit the linkage to shift the hook from an unloaded or ground level position to a fully forward loaded position with the use of only two rams and yield the advantage that these rams can be simply controlled to operate in sequence.

Claims

1. A mechanism for loading and unloading a container or platform over the rear of the vehicle includes an arm (herein called a hook arm) at one end of which is disposed a hook or gripping member by which the mechanism can be connected to a container or platform, the arm forming part of a linkage which is operable by sequential extension of a first ram and a second ram, the arrangement of the linkage being such that sequential operation of the rams shifts the hook between a first or loaded position in which the linkage is located wholly beneath the container or platform and a second or 'pick-up' position in which the hook or gripping member is disposed substantially at ground level at the rear of the vehicle._.

2. A mechanism, for loading and unloading a container or platform over the rear of a vehicle, which includes a first frame which is pivotally connected to a hook arm in such a way that the hook arm can be caused to describe a movement through substantially 270° in a vertical plane under the act-ion of two or more rams.

3. A mechanism according to Claim 1 or 2 in which the preferred arrangement includes a number of sub-links which serve to convert the direction of the thrust or pulling force of the first or second ram to a desired direction to achieve pivoting movements of the frame and hook arm which result in desired hook movement.

4. A mechanism according to Claim 1 in which the frame has one of its ends pivotally connected to the chassis and its other end pivotally connected to a sub-link herein called a second sub-link which in turn is pivotally connected to a first sub-link, the first sub-link serving to transmit a force applied by the hook arm ram to cause a pivoting movement of the hook arm.

5. A mechanism according to Claim 4 which includes a sub-link herein called a fourth sub-link pivotally connected to the frame near the end of the frame which is connected to the chassis, the fourth sub-link being pivotally connected to a third sub-link, the third and fourth sub-links serving to locate one end of the main ram in such a position that its extension or contraction causes a pivoting movement of the frame about its pivotal connection to the chassis.

6. A vehicle having mounted thereon a mechanism for loading and unloading a container or a platform over the rear of the vehicle in accordance with any preceding claim.