GB1564899A - Hydraulic system for actuating a tailgate of a tipping body of a load carrying vehicle - Google Patents

Description

(54) HYDRAULIC SYSTEM FOR ACTUATING A TAILGATE OF A TIPPING BODY OF A LOAD CARRYING VEHICLE (71) I, JOHN STEPHEN WRENCH, a British citizen, of Beeches Farm, Saltney Ferry, Chester, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention concerns an hydraulic system for actuating a tailgate of a tipping body of a load carrying vehicle.

According to the present invention an hydraulic system for actuating a tailgate of a tipping body of a load carrying vehicle comprises two hydraulically interconnected piston and cylinder assemblies, one of the assemblies operable between the tipping body and a rigid fixed member on the vehicle, the other of the assemblies operable between the tailgate and the tipping body whereby raising and lowering of the tipping body results in the transfer of hydraulic fluid between the two assemblies to effect movement of the tailgate.

The invention will be described further, by way of example only, with reference to the diagrammatic drawings accompanying the Provisional Specification.

In the drawing reference numeral 1 denotes a chassis member and reference numeral 2 denotes a tipping load carrier or body which is carried on the chassis. The body 2 can be tipped or tilted by rams or jacks in a usual manner between a lowered position and a raised position, at which latter the load can slide out of the body. The body is provided with a tailgate or tailboard 3 which is hinged at 4 to the rear end of the body. The tailgate 3 can be arranged to cooperate with a tophinged gate (not shown) which forms an end closure for the body 2.

A first piston and cylinder assembly 5 is suspended from the base of the body 2 at a position above the chassis member 1. The cylinder of the assembly 5 can be pivotally connected to hang free under gravity from a support 6 secured to the base of the body 2.

The piston of the assembly 5 is provided with a piston rod 7 which extends outwardly beyond the cylinder.

A second piston and cylinder assembly 8 is connected between the body 2 and the tailgate 3. Conveniently one end of the cylinder of the assembly is pivotally connected at 9 to the rear end of the body and the free end of the piston rod of the assembly is pivotally connected at 10 to the tailgate 3.

The pistons of the two assemblies 5 and 8 are in sealing sliding engagement with their respective cylinders and the closed ends of the cylinders are interconnected through a pipeline or conduit 11. The conduit can conveniently be provided with a valve 12 for the introduction of an hydraulic fluid.

In the drawing the body is shown in a raised position with the tailgate open. Upon lowering the body, the end of the piston rod 7 of the first assembly 5 contacts the chassis member 1 and as the body continues to fall so that the cylinder of the assembly 5 moves downwardly relative to the now fixed piston, hydraulic fluid is forced out of the first assembly and into the second assembly to move its piston outwardly thereby pivoting the tailgate about its pivot or hinge connection 4 into a raised, closed position. The tailgate is thereby securely locked in its raised position.

Upon raising the body 2 into a tilted position for unloading the reverse conditions apply. Raising the body causes the cylinder of the first assembly to move relative to the piston to increase the volume of the fluid chamber therein. The weight on the tailgate is such as to cause the piston of the second assembly to pump fluid back into the first assembly thereby enabling the tailgate to irop into its lowered position.

The arrangement is completely automatic and does not require any manual aids. The tailgate opens and closes in response to movement of the tipping body.

Whereas the invention has been described with reference to a single second piston and cylinder assembly 8 it will be appreciated that a plurality of such assemblies can be utilised.

For example two such assemblies can be provided one at each side of the tailgate with a T-junction in the conduit providing communication with the two assemblies.

It might be desirable to fixedly secure the assembly 5 to the base of the body 2 to ensure that the piston-rod 7 does contact a fixed support on the chassis. When the assembly is suspended freely from the support 6 it is possible that a jerking movement of the vehicle will cause the rod 7 to miss contact with the fixed support in the chassis member.

Yet again, the support on the chassis can be provided with a wide-angle well or the like to serve as a guide for the piston rod.

Further it will be apparent that the positions of the respective pistons and cylinders can be reversed, for example the piston rod of the first assembly can be suspended from the body 2 with the cylinder body adapted to contact the chassis member. Preferably the volume of the fluid compartment in the first assembly 5 is greater than the volume of the fluid compartment in the second assembly 8 or the combined volume of such compartments in the case of more than one second assembly 8 in order to generate an excess pressure in the hydraulic system to positively urge the tailgate into its closed position when the body is in a lowered position.

Attention is directed under Section 8 of the Patents Act 1949 to Specification No.

1,522,313 and the following claims exclude anything claimed therein.

Subject to the foregoing disclaimer, WHAT I CLAIM IS:- 1. An hydraulic system for actuating a tailgate of a tipping body of a load carrying vehicle comprising two hydraulically interconnected piston and cylinder assemblies, one of the assemblies operable between the tipping body and a rigid fixed member on the vehicle, the other of the assemblies operable between the tailgate and the tipping body whereby raising and lowering of the tipping body results in the transfer of hydraulic fluid between the two assemblies to effect movement of the tailgate.

2. An hydraulic system for actuating a tailgate of a tipping body of a load carrying vehicle substantially as herein described with reference to and as illustrated in the drawing accompanying the Provisional Specification.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. assembly 5 to the base of the body 2 to ensure that the piston-rod 7 does contact a fixed support on the chassis. When the assembly is suspended freely from the support 6 it is possible that a jerking movement of the vehicle will cause the rod 7 to miss contact with the fixed support in the chassis member. Yet again, the support on the chassis can be provided with a wide-angle well or the like to serve as a guide for the piston rod. Further it will be apparent that the positions of the respective pistons and cylinders can be reversed, for example the piston rod of the first assembly can be suspended from the body 2 with the cylinder body adapted to contact the chassis member. Preferably the volume of the fluid compartment in the first assembly 5 is greater than the volume of the fluid compartment in the second assembly 8 or the combined volume of such compartments in the case of more than one second assembly 8 in order to generate an excess pressure in the hydraulic system to positively urge the tailgate into its closed position when the body is in a lowered position. Attention is directed under Section 8 of the Patents Act 1949 to Specification No. 1,522,313 and the following claims exclude anything claimed therein. Subject to the foregoing disclaimer, WHAT I CLAIM IS:-

1. An hydraulic system for actuating a tailgate of a tipping body of a load carrying vehicle comprising two hydraulically interconnected piston and cylinder assemblies, one of the assemblies operable between the tipping body and a rigid fixed member on the vehicle, the other of the assemblies operable between the tailgate and the tipping body whereby raising and lowering of the tipping body results in the transfer of hydraulic fluid between the two assemblies to effect movement of the tailgate.

2. An hydraulic system for actuating a tailgate of a tipping body of a load carrying vehicle substantially as herein described with reference to and as illustrated in the drawing accompanying the Provisional Specification.