GB2194925A

GB2194925A - Lowerable trailer suspension arrangement

Info

Publication number: GB2194925A
Application number: GB08621988A
Authority: GB
Inventors: Richard Lee Tomecek
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-09-12
Filing date: 1986-09-12
Publication date: 1988-03-23
Anticipated expiration: 2006-09-12
Also published as: GB8621988D0; GB2194925B

Abstract

This invention relates to a wheeled trailer comprising a load carrying body which is supported by wheels. In accordance with the invention such a trailer has at least one wheel on each of its lateral sides and there is provided jacking means which can be operated to lift the trailer relative to the ground to an upper position in which the wheels are clear of the ground. Each wheel of the trailer is connected to the body by a suspension system which permits limited relative movement in an up and down direction between the wheel and the body but which can be arranged when desired in an alternative inoperative configuration in which the associated wheel can move upwardly in its own plane relative to the body. Each of said suspension systems incorporates a leaf spring which is connected at one end to a member which is pivotable relative to the body and which is free at its other end so as to be engageable in its operative position with a moveably mounted abutment and said abutment is removeable from the trailer or moveable to an inoperative position in which it is not engaged by the free end of said leaf spring. (Jacks not shown in Fig. 1). <IMAGE>

Description

SPECIFICATION Trailer This invention relates to a wheeled trailer which is intended for use in carrying goods or materials and which can be towed by a suitable vehicle such as for example a van, car or other road vehicle or an agricultural tractor.

Such a trailer comprises a load-carrying body or platform which is supported by wheels, said body or platform being of course spaced from the ground when the trailer is in its operative, "towable" position. It is, however, desirable, in order to facilitate loading or unloading of the trailer, and also possibly in order to maintain stability of the trailer when it is detached from a towing vehicle, to arrange that said body or platform can be lowered from its operative position to a position in which it rests on, or is closely adjacent to, the ground. Hitherto known arrangements for providing this facility have not been entirely satisfactory for various reasons and the object of the present invention is to provide an improved construction of trailer in which the load-carrying body or platform can be readily brought into or close to engagement with the ground when desired.

In accordance with the invention there is provided a trailer which comprises a load-carrying body or platform having on each of its lateral sides at least one wheel and wherein there is provided jacking means which are engageable with the ground and which can be operated to lift the trailer relative to the ground to an upper position in which the or each wheel on each side of the trailer is clear of the ground, the or each wheel on each side of the trailer being connected to said body or platform by means of a suspension system incorporating resilient means which, when in its operative, wheel-supporting position, permits a limited amount of relative movement in an up-and-down direction between the wheel and the body or platform (such movement being limited by stressing of said resilient means), but which can be disposed when desired in an alternative and inoperative configuration in which the associated wheel can move upwardly in its own plane relative to said body or platform whereby subsequent lowering of the trailer on said jacking means after it has been lifted thereby, and after each wheel suspension system linkage has been set in its inoperative configuration, will result in the associated wheels being displaced upwardly relative to the body or platform in their own planes in order that said body or platform can be lowered into, or close to engagement with the ground, each of said suspension systems incorporating a leaf spring which is connected at one end to a member which is pivotable relative to the trailer body or platform and which is free at its other end so as to be engageable in its operative position with a movably mounted abutment, said abutment being removable from the trailer or movable to an inoperative position thereon in which it is not engaged by the free end of said leaf spring.

The trailer may be provided on each side with a pair of wheels in which case there would be a leaf spring associated with each wheel. There may then be provided on each side of the trailer one pivotally mounted abutment which, in the operative position of the suspension, is engaged by the free ends of both of the leaf springs on the corresponding side of the trailer. Conveniently said jacking means includes a pair of skids which are mounted beneath the trailer and which are movable between a relatively raised position (adjacent the underside of the trailer) and a relatively lowered position (spaced from the underside of the trailer) by means of a fluid pressure actuated piston and cylinder unit.

The invention will now be more particularly described with reference to the accompanying drawings wherein: Figure 1 is an "exploded" perspective view of one example of a trailer constructed in accordance with the present invention, Figure 2 is a plan view of the trailer seen in Fig. 1, Figures 3 and 4 are respectively side and end views of the trailer shown with the jacking means in a lowered position relative to the trailer in order that the latter can be lifted into a position in which the wheels are clear of the ground and Figures 5 and 6 are respectively side and end views of the trailer after the wheel suspensions have been set in an inoperative position and the aforesaid jacking means has been raised relative to the trailer so that the trailer is placed in a lowered position in which its body or platform is adjacent to the ground.

Referring now to the drawings there is shown therein a trailer generally indicated by reference numeral 10, said trailer having a base or platform 11 supported on a steel frame 12, together with a pair side walls 13 and 14 and a pair of end walls 15 and 16.

The trailer is supported on each side by at least one, and, as shown, a pair of wheels such as wheels 17 and 18. Each of said wheels is mounted on the trailer by means of a suspension unit generally indicated by reference numeral 19. Each of said suspension units comprises a box-like structure 20 which is open at its inner end 21 and from its outer end 22 there projects in a lateral direction a generally cylindrical member 23 which is arranged to enter into a hollow axle member 24 and to be secured against longitudinal movement therein so that said member 23 and the box 20 to which it is attached can pivot relative to the trailer body or platform about the axis of said member 23. The box 20 carries, on its outer surface, a stub axle 25 on which a wheel (such as wheel 17 or 18) can be mounted.

Furthermore, each of said suspension units 19 incorporates a leaf spring 26 which at one is formed to spiral configuration and connected to the outer end of the associated member 23. The opposite end, namely end 26a, of each leaf spring is free and is adapted in its operative position to enter into one end of an open-ended further box-like structure which forms a compensator member 27.

There is thus one compensator member disposed on each side of the trailer and each compensator member is pivotally mounted on a short pivot 28 which projects outwardly from the side of the trailer. In the operative condition of the suspension units, each compensator member 27 is located and secured axially on its pivot 28 by means of a collar 29 which can be secured to the pivot as by means of a radially extending screw or the like (not shown) but the collar can be re-.

moved to enable the member 27 to be dismounted from its pivot 28 when the suspension units are to be arranged in their inoperative positions.

Beneath each of said compensator members 27 is a stop plate 29 which is secured to the trailer frame 12 and which serves to limit the pivotal movement of the associated compensator member 27 (in either direction of rotation) relative to said frame. A pin 30 extends across the bottom of the end of each box-like structure 20 and engages the underside of the associated leaf spring 26.

The trailer is also provided with jacking means which include a pair of skids 34 and 35 which are mounted beneath the underside of the trailer so that they are in a spaced parallel relationship, each skid extending in a direction parallel to the fore-and-aft axis of the trailer. Said skids 34 and 35 are suspended from pivoted parallel links 36 which are pivotally connected at one end to the skids and at the other end to the aforesaid steel frame 12.

The skids are also connected to cross members 37 and 38 which are further connected to one end of a fluid pressure actuated piston and cylinder unit in the form of an hydraulic ram 39. There is also provided a hand operated pump 40 together with an hydraulic reservoir, the arrangement being such that said pump can be actuated to extend the ram 29 in order that the aforementioned skids 34 and 35 can be lowered relative to the trailer in order that the trailer may be raised.

Figs. 3 and 4 show a situation in which the ram 39 has in fact been extended by operation of the pump 40 so that the skids 34 and 35 have been lowered to engage the ground and lift the trailer 10 to a position in which the wheels are clear of the ground as will be particularly seen in Fig. 4. At this. time the aforementioned suspension units 19 supporting the wheels will be in their operative wheel supporting positions but the aforementioned collars 29 and the associated compensator members 27 can now be removed in order to permit the box-like structures 20 (now under no restraint by the leaf springs 26) to pivot upwardly on the members 23 whereafter the hydraulic pressure in the ram 39 can be relieved on operation of an appropriate valve whereupon the trailer 10 will sink under its weight and the skids 34 and 35 will be forced to assume a position in which they are adjacent to the underside of the trailer.

During such downward motion of the trailer the wheels will each be able to move vertically upwards in their own planes relative to the trailer and the trailer will then assume the position shown in Figs. 5 and 6 where it can readily be loaded or unloaded. When it is required to rearrange the trailer in a towable position the skids 34 and 35 are again extended by operation of the ram 39 so that the trailer is again lifted to a position in which the ground engaging wheels will fall freely into the positions shown in Figs. 3 and 4 whereafter the suspension units are reconnected by remounting the compensator members 27 on their pivots 28 and securing the collars 29 to the outer ends of the pivots. The free ends of each pair of leaf springs will then project into the interior of the associated compensator member 27.The ram 39 is then again retracted so as to lower the trailer into a position in which the wheels engage the ground again and the skids are withdrawn to a position in which they lie adjacent to the underside of the trailer.

In the operative position of the suspension units 19, the free end of each leaf spring 26 will engage one of a pair of pins 31 which extend respectively across the top of the ends of the associated compensator member 27 whilst, as previously stated, the underside of each leaf spring 26 intermediate its ends will engage one of the pins 30. With such an arrangement, if, for example, the wheel 17 in use rises slightly on passing over a hump in the ground then the box 20 will tend to pivot in an anti-clockwise direction. The free end 26a of the leaf spring 26 of the left hand box 20 (as seen in Fig. 1) will then tend to tip the compensator member 27 in a clockwise direction and the opposed pivotal movements of said left hand box 20 and said compensator member 27 will act to stress both of the leaf springs 26. Upward movement of the wheel 18 will of course cause similar pivotal movements of the right-hand box 20 and the compensator member 27 - but in the opposite directions of rotation - both leaf springs 26 will again be stressed.

It is also to be understood that the ram 39 can be positioned if desired in a position other than that shown in the drawing. It can for example be arranged so that its lower end is pivotally connected to a cross member of a frame of which the skids 34 and 35 form a part, such cross member being arranged intermediate the ends of said frame. The upper end of such ram may then be connected to the chassis or base of the trailer 10 at any convenient point which for instance may be remote from the pump 40. Furthermore instead of said pump 40 being manually operable as above described it may be connected to power operated means such as a suitable 12 volt power pack arranged so that the jacking system can then either manually or electrically operated. As a further alternative, and where the trailer is intended for connection to an agricultural tractor, the ram itself may be adapted for connection to the hydraulic power system of the tractor.

Claims

1. A trailer which comprises a load-carrying body or platform having on each of its lateral sides at least one wheel and wherein there is provided jacking which are engageable with the ground and which can be operated to lift the trailer relative to the ground to an upper position in which the or each wheel on each side of the trailer is clear of the ground, the or each wheel on each side of the trailer being connected to said body or platform by means of a suspension system incorporating resilient means which, when in its operative, wheel-supporting position, permits a limited amount of relative movement in an up-anddown direction between the wheel and the body or platform (such movement being limited by stressing of said resilient means), but which can be disposed when desired in an alternative and inoperative configuration in which the associated wheel can move upwardly in its own plane relative to said body or platform whereby subsequent lowering of the trailer on said jacking means after it has been lifted thereby, and after each wheel suspension system linkage has been set in its inoperative configuration, will result in the associated wheels being displaced upwardly relative to the body or platform in their own planes in order that said body or platform can be lowered into, or close to, engagement with the ground, each of said suspension systems incorporating a leaf spring which is connected at one end to a member which is pivotable relative to the trailer body or platform and which is free at its other end so as to be engageable in its operative position with a movably mounted abutment, said abutment being removable from the trailer or movable to an inoperative position thereon in which it is not engaged by the free end of said leaf spring.

2. A trailer as claimed in Claim 1 wherein a pair of wheels is provided on each side of the trailer.

3. A trailer as claimed in Claim 2 wherein a leaf spring is provided in association with each wheel.

4. A trailer as claimed in Claim 2 or Claim 3 wherein there is provided, on each side of the trailer, a pivotally mounted abutment which, in the operative position of the suspension system is engaged by the free ends of both of the leaf springs on the corresponding side of the trailer.

5. A trailer as claimed in any one of the preceding claims wherein said jacking means incorporates a hand-actuated hydraulic pump and hydraulically actuated piston-and cylinder means.

6. A trailer as claimed in Claim 6 wherein said jacking means incorporates movable skid means which are adapted to support the trailer when they are lowered relative to the trailer platform or body.

7. A trailer substantially as hereinbefore described with reference to and as shown in the accompanying drawings.