GB2135658A - Trailer arrangement - Google Patents

Abstract

A trailer has a lifting frame (5) which may either tilt a load container (7) or may lift the load container from the trailer and place it on the ground. The lifting frame has a first part pivotally connected to the chassis (1) of the trailer, and a second part (10) articulated to the first part. For tilting the load container, a locking device rigidly locks the two parts of the lifting frame together whilst permitting pivotal movement of the first part relative to the chassis. For lifting a load container from the trailer, the locking device holds the first part to the chassis and permits the two parts to move in relation to each other. The locking device comprises two locking members one for locking the first part of the lifting frame to the chassis and the other for locking the two parts together. The two locking members are connected in such a way that when one locks the other always releases. <IMAGE>

Description

SPECIFICATION Trailer arrangement The present invention relates to an arrangement of trailers, which supports a load container via a lifting frame, which is so arranged as to be capable of being pivoted upwards about a bearing at the end of the chassis. At a certain distance from the bearing is an articulated joint at the centre of the chassis between a first part of the lifting frame, which is connected to the chassis by means of the bearing, and a second, outer part of the lifting frame. The lifting frame together with the load container can be swung upwards in its entirety about the bearing for tipping.

Alternatively, it may be swung upwards with the outer part by a movement in the articulated joint, whilst the first part is retained in position. In this way the load container is raised and moved by its outer end in the direction of the end of the chassis for the purpose of removing it from the lifting frame. By causing the outer part of the lifting frame to swing inwards, the load container may alternatively be raised up onto the lifting frame. A power source is arranged between the chassis and the outer part of the lifting frame and is abie to keep apart the chassis and the lifting frame under compression.

Trailer arrangements for the purpose of supporting a load container with a chassis are known by means of which the load container can be tipped as required for the purpose of discharging a load or of removing the load container or of raising it, for instance from the ground.

It is common for such arrangements to be executed on self-propelled vehicles, which are equipped with complex control and power systems usually of a hydraulic nature. However, a certain level of demand has been found to exist for simpler types of trailer, which can be executed as towed vehicles or as semi-trailers. It is important in this respect to keep the acquisition cost within tight limits, which do not permit the aforementioned complex equipment to be provided.

The object of the present invention is to produce an arrangement which considerably simplifies the mechanism for a trailer of said type, enabling a low manufacturing cost to be achieved.

A further object of the invention is to produce an arrangement which exhibits a high degree of security against incorrect operation in spite of its simplicity.

According to the present invention, a trailer comprises a chassis, which supports a load container via a lifting frame which has a first part pivotally connected to the chassis and a second part articulated to the first part and connected to the load container and a locking device on the parts which, when in a first position rigidly locks the first part to the second while permitting pivotal movement of the first part relative to the chassis, and when in a second position holds the first part of the lifting frame to the chassis and permits the parts of the lifting frame to move in relation to each other about the articulation.Preferably the locking device comprises a first locking element (which may be a pin) which, in the first position, provides a connection between a contact surface on the first part of the lifting frame and a contact surface on the second part, and a second locking element (for example a rod or bar) which, in the second position provides a connection between a contact surface on the first part of the lifting frame and a contact surface on the chassis.

The contact surfaces associated with the first locking element may be holes, which are preferably provided by sleeves.

The contact surface which is on the first part of the lifting frame and associated with the second locking element is preferably a plate having a recess which, in the first position, is aligned with a projecting part, or pin, on the second locking element. The contact surface on the chassis may be a sleeve, or guide, for the second locking element.

In the accompanying drawings there is illustrated a preferred embodiment of the invention.

Figure 1 shows a side view of a complete trailer; Figures 2 and 3 show respectively a view from the side and a view from the top of the trailer chassis; Figures 4 and 5 similarly show a lifting frame intended to be installed on the chassis; Figures 6 and 7 also show in a similar fashion a support for a load container; Figure 8 shows a side view of a detail of the lifting frame; and Figure 9 shows the same detail viewed from above, with the last two Figures being on a larger scale than the others.

In accordance with Figure 1 a trailer has a chassis 1 with a bogie 2, a draw bar arrangement 3 for connection to a tractor vehicle and a supporting leg 4 on which to stand the trailer when it is separated from the tractor vehicle. The chassis 1 supports a lifting frame 5 and a load frame 6, which finally supports a load container 7.

The lifting frame is articulated along a shaft arrangement 14, which extends across the trailer, so that the frame is able on the one hand to adopt the position illustrated with solid lines in Figure 1, in which it is straight and runs parallel with an under part 8 of the load frame 6 for the entire length of a corresponding under part 9, which is shown in Figures 4 and 5, but which is hidden from view in Figure 1. Alternatively the lifting frame 5 may be articulated about said shaft, so that a front part 10, as illustrated by dotted and dashed lines in Figure 1, is caused to swing upwards and backwards whilst the remaining rear part retains its original, horizontal position.This swinging motion also involves an upright front part 1 which is rigidly connected to the front part 10 and which thus extends vertically upwards when the front part 10 is in its horizontal position.

When the lifting frame 5 adopts its straight position, it is, however, possible that it may not simply be horizontal, or to put it more correctly in a position parallel with the base 12, upon which the trailer rests, but may also be caused to swing upwards and rearwards about a shaft 1 5 on the rear part of the chassis.

When the lifting frame adopts its position parallel with the base 12, the load container 7 will adopt its transport position. When the lifting frame adopts its aforementioned upward-swung position, in which it is still flat and is pivoted about the shaft 15, the load container will adopt the tipped position, allowing its contents to fall out from the rear part of the container. In order to facilitate this the rear part may be provided with a collapsible or detachable flap.

When the lifting frame is caused to turn about said shaft 14 at its mid point, as shown with dotted and dashed lines in Figure 1, the front part 10 and the front part 11 will act as a lifting and removal arm which first raises the front part of the container and moves the entire container backwards in order finally, once the container has slid down onto the base 12 with its rear part, to lower the front part onto the base, so that the entire container is placed on the base. It is this final position that is shown with dotted and dashed lines in Figure 1. Arrangements which operate in accordance with these principles of movement have been previously disclosed, but differ in other respects with regard to their embodiment from what will be indicated in the following specification of the invention.

In accordance with Figures 2 and 3 the chassis 1 exhibits in addition to said bogie 2 and drawing attachment 3 a frame 1 6 consisting essentially of two longitudinal members 17, a front crossmember 18 and a rear cross-member 19. On the rear member at either side is a bearing 20 for said shaft 1 5. In front of the bearing 20 is arranged at either side a hook-like hasp 21 open to the rear. At the front end of the chassis next to the drawing arrangement 3 is arranged a bracket 22 for a hydraulic cylinder 23, the further connection of which will be described later.

The lifting frame illustrated in Figures 4 and 5 has been described earlier in certain respects. It thus comprises a horizontal part with a rear component 9 and a front component 10 as well as an upright front part 11. The rear and the front components 9, 10 are articulated in relation to each other by means of the shaft arrangement 14.

The rear component projects with a part 24 ahead of the shaft arrangement whilst the front component 10 terminates essentially at the same level as it. The rear component 9 terminates on either side in a bearing 25. The front component 10 exhibits a bearing arrangement 26, which is intended to serve as a mounting for said hydraulic cylinder 23. This is thus accommodated between the bracket 22 on the chassis 1 and the bearing arrangement 26 on the lifting frame 5. In this way the actual cylinder is attached to the bracket and the piston-rod of the cylinder is attached to the bearing arrangement 26, in such a way that these two components can be kept apart from each other positively by the operation of the cylinder.

The upright part 11 terminates at the top in a hook, 27. The lifting frame is made to fit with regard to its width between the two longitudinal members 1 7 of the chassis and it is designed to be connected to the chassis in such a way that it is free to pivot by means of the shaft 1 5, which extends through the bearing housings of the bearings 20 and 25.

As will already have been appreciated the load frame 6 in accordance with Figures 6 and 7 comprises a horizontal part 8 consisting of two longitudinal members 29 and between these three cross-members 30. Also present is an upright component 31 ,which terminates in a lifting ring (in Figure 6 the lifting frame is shown cut away in the part where the lifting ring 32 is situated). To the rear each of the two longitudinal members 29 terminates in a foot 33 rounded at the bottom.

From the inside of each and every one of the members projects inwards a pin 28 intended to engage in the corresponding hasp 21 (Figures 2, 3).

The load frame 6 is designed with regard to its width to be positioned with its longitudinal members 29 outside the members 17 of the chassis, with the load frame thus resting against the chassis by its two cross-members 30. The upright front part 31 is so designed with regard to its height that the lifting ring 32 lies inside the hook 27 of the lifting frame 5 when the specified components are placed one above the other in the manner indicated in Figure 1. At the rear end the pins 28 will thus be introduced into the hasps 21.

In Figures 8 and 9 are shown details of a locking arrangement, which may also be seen in broad outline in Figures 2-5. This locking arrangement, which in its entirety is identified by the reference designation 34, consists of a sleeve 25 containing a hole 36 welded onto the front part 10 of the lifting frame. A pin 37 with two driving ears 38 is so arranged as to be capable of moving in the hole 36. To the pin is connected an operating rod 39 which, as illustrated in Figure 5, is connected to an operating organ 40. The operating organ consists essentially of a lever by means of which the operating rod can be caused to move backwards and forwards between two positions. In one position, known as the 'change position', the pin 37 is pushed forwards into the position illustrated in Figures 8 and 9, so that its slightly pointed end is inside the hole 36. In the other position, known as the 'tipping position', the pin is pushed backwards, so that it is not only in the hole 36 but is also in a hole 42, inside a sleeve 43, which is attached right at the front of the rear component 9 of the lifting frame, and hence on the end of the part 24 which projects beyond the bearing arrangement 14.

The locking arrangement 34 also comprises a sleeve 44 attached to the longitudinal member 17 of the chassis 1, said sleeve being designed to permit the forward and backward movement of a flat bar 45. The flat bar is provided with a pin 46 at its front end which engages in the slot between the driving ears 38 on the pin 37. At its rear end the bar 45 is provided with a second pin 47 which, when the rear component 9 and the front component 10 of the lifting frame are in line with each other, is situated above a plate 48 which is itself attached to the projecting part 24 of the rear component 9. The plate 48 has a recess 49, the base of which extends to a greater depth than the end of the pin 47.

It must also be mentioned that the shaft 1 5 is provided at its ends with rollers 52 with an inner track against which tracks the longitudinal members 29 of the loading frame 6 can rest, at the same time as they are guided by outer discs having a greater diameter than the tracks. To the cylinder 23 shall be provided a supply of hydraulic fluid so that the piston-rod can be moved between the fully retracted and the fully extended positions, and vice-versa. As it is presupposed that the mechanism must be of a simple type and capable of functioning even without a tractor vehicle being present, provision may be made for the use of a hand pump. Alternatively, unions may be provided for connection to, for instance, the hydraulic system of a tractor.The possibility also exists within the scope of the invention of incorporating some other form of power source, for example a screw.

The load container 7 is not illustrated separately. It is arranged, however, so as to rest on the load frame 6 and it is attached to the load frame during driving and handling operations.

Different types of container may be used for different transport requirements and the different containers can be exchanged one for another. It is presupposed, however, that one or more types will be designed for tipping.

The manner in which the different component parts rest upon and inside each other is shown in Figure 1 and has also been described in the above specification. In the position illustrated in Figure 1, being the transport position, the load frame 6 is held by the ring 32 of the hook 27 at the same time as its rear end is secured against upward movements by the hasps 21. through the interaction of the latter with the pins 28.

The lifting frame 25 is secured at its side to the chassis by means of the shaft 1 5 and is also connected to the chassis via-the hydraulic cylinder 23.

If it is wished to remove the load container together with the lifting frame hydraulic fluid is supplied to the hydraulic cylinder 23 to a point below its piston, causing the piston-rod to be forced out. For this purpose the locking arrangement must remain in the position illustrated, being the 'change position'. In this position the rear component 9 of the lifting frame 5 is locked to the chassis 1 by the projection above the upper side of the plate 48 of the pin 47 (see Figures 8 and 9) attached to the chassis. The rear component 9 is thus prevented from being swung upwards. The front component 11 is, however, free to swing upwards about the shaft arrangement 1 4. In this way the hook 27 on the front component 11 will lift the loading frame upwards and backwards by means of the ring 32.

For this purpose its front end is raised at the same time as the entire loading frame is pushed backwards with the members 29 running over the rollers 52. The pins 28 slide out of the hasps 21 as the rearward movement takes place. The feet 33 will gradually reach the base 12 and the continued swinging of the front component 1 0 with the front part 11 will cause the front part of the loading frame to be pushed beyond the rear part of the lifting frame and the chassis, whereupon the front end of the loading frame will also be lowered down towards the base. Finally the loading frame with the load container will have been lowered onto the base in the position illustrated by dotted and dashed lines in Figure 1. Further lowering of the hook 27 will cause it to be released from the ring 32 so that the trailer can be moved forwards slightly, thereby fully disengaging the hook.By reversing the flow of the hydraulic fluid, the piston-rod can then be drawn back into the hydraulic cylinder 23, thereby causing the front part of the lifting frame to swing back down.

The trailer is now ready to pick up another container. This takes place in the order to that indicated for putting down a container. For this purpose the trailer is backed up so that the hook on the swung-down front component 9 of the lifting frame will engage with the ring 32 of the container in question. The front component of the lifting frame is then swung forwards, causing the front component of the lifting frame first to be raised and then to be brought up onto the rollers 25, whereupon it is pulled forwards until it adopts the position illustrated in Figure 1.

If it is wished instead to keep the load container on the trailer whilst it is tipped, so that material such as sand or earth can be tipped directly out via its rear edge, the locking arrangement 34 must be left with the pin 37 in its rearward position in which it will be engaged in both the holes 36 and 42. There is achieved by means of the operating organ 40. For this purpose the pin 47 on the bar 45 will be located in the recess 49 in the plate 48.

In this way the rear component 9 of the lifting frame 5 is not prevented from swinging about the shaft 1 5. The pin 37 will, on the other hand, prevent the two components 9 and 10 of the lifting frame from pivoting in relation to each other about the shaft arrangement 1 4.

If the hydraulic cylinder 23 is actuated in this position the lifting frame 5 will accordingly be caused to swing in its entirety, and this will take place about the shaft 1 5. The load frame 6 with the container 7 is retained by the hook 29 by means of the ring 32 and will thus remain in its positions in relation to the lifting frame 5. The entire unit consisting of the lifting frame 5, the load frame 6 and the container 7 will thus be caused to tip backwards in the intended fashion.

Once the tipping operation is complete the component parts can be caused to swing back by reversing the movement of the hydraulic cylinder.

The arrangement can thus be re-set by means of the simple and robust locking arrangement 34 between the 'change position' for setting down or picking up the load container and the 'tipping position'. Changes to the function of the power source, in this case the hydraulic cylinder, need not be undertaken unless the resulting pattern of movement is determined fully by the position of the locking arrangement.

Claims (6)

1. A trailer comprising a chassis, which supports a load container via a lifting frame which has a first part pivotally connected to the chassis and a second part articulated to the first part and connected to the load container and a locking device on the parts which, when in a first position rigidly locks the first part to the second while permitting pivotal movement of the first part relative to the chassis, and when in a second position holds the first part of the lifting frame to the chassis and permits the parts of the lifting frame to move in relation to each other about the articulation.

2. A trailer according to Claim 1 wherein the locking device comprises a first locking element which, in the first position, provides a connection between a contact surface on the first part of the lifting frame and a contact surface on the second part, and a second locking element which, in the second position provides a connection between a contact surface on the first part of the lifting frame and a contact surface on the chassis.

3. A trailer according to Claim 2, wherein the first locking element is a pin which can be inserted into sleeves which provide the contact surfaces associated with the first locking element.

4. A trailer according to Claim 2 or Claim 3, wherein the second locking element is a rod having a projecting part and the contact surface on the chassis is a guide for the rod.

5. A trailer according to claim 4, wherein the contact surface on the first part of the lifting frame, associated with the second locking element is a plate having a recess with which the projection is aligned in the first position.

6. A trailer substantially as herein described with reference to and as illustrated in the accompanying drawings.