GB2093902A - Tailgate locking means - Google Patents

Abstract

A refuse collection and compaction vehicle is provided with a tailgate locking arrangement (17) comprising a pair of rigid apertured members (19 and 20) on the tailgate and an apertured member (18) on the body (11) of the vehicle, which lies between the apertured members (19 and 20) in the normal closed condition of the tailgate (13). A spring loaded plunger (24) normally extends through the aligned apertures to lock the tailgate. Release of the tailgate is by a piston and cylinder assembly (26) which withdraws the plunger (24) against its spring (27). The cylinder (26) and the main lifting rams (16) of the tailgate can be operated sequentially by a single control valve so as to unlock and then lift the tailgate (13). <IMAGE>

Description

SPECIFICATION Tailgate locking means This invention relates to a tailgate locking means primarily for refuse collection and compaction vehicles.

Refuse collection and compaction vehicles of the type with which this invention is concerned comprise a vehicle chassis, a hollow refuse container body and a tailgate which is provided with means for receiving and compacting refuse and passing it into the body. The tailgate is pivotally mounted so as to cover an opening at the rear of the container body, with the periphery of the tailgate and that of the opening being in abutment. The tailgate is pivotally mounted at its upper edge to the body and can be swung upwardly about this pivotal mounting to reveal the open end of the container body from which the refuse can be discharged. Such refuse collection and compaction vehicles are referred to as being "of the type specified".

It is usual to provide a vehicle of the type specified with sealing means acting between the tailgate and the body opening so as to prevent liquids which may be in the refuse from draining out of the refuse or being forced out of the refuse during compaction. It is also conventional to arrange the opening at the rear of the container body in a plane slightly inclined to the vertical so that the weight of the tailgate tends to hold it against this opening, to force the sealing means into firm sealing engagement.

However, it is necessary to have means for locking the tailgate against the body since there are high reaction forces acting on the tailgate during the operation of compacting the refuse.

Refuse may be compacted in a ratio of about 4:1 by volume and very substantial forces are therefore exerted.

Tailgate locking devices of a manually operated type are already known and in common use. For example, each side of the tailgate may be locked at the base by a screw-threaded member pivoted on the container body and manually rotated into abutment with an apertured member on the tailgate. This arrangement has the disadvantage that the operator has to leave the vehicle to unlock the tailgate, for example at a tip or incinerator where the load is to be discharged. The manually operated devices are time consuming to operate, especially as it is necessary to provide one at each side of the vehicle and the vehicle would normally be parked at a tip in such a way that the person unlocking the tailgate could not pass round the rear of the tailgate to open the second of the locking devices.

Furthermore, since the devices are accessible from outside the vehicle, it is possible for unauthorised persons to tamper with them, possibly resulting in accident or injury when the compaction apparatus is operated.

It has also been proposed to utilise the hydraulic lifting rams of the tailgate firstly to release and then to raise the tailgate. This has been achieved by providing a pair of slotted brackets on the body to receive the tailgate pivots.

When the rams are initially operated, the tailgate slides upwardly relative to the opening in the vehicle container body as the pivots move to the upper ends of the slots in the bracket. The base of the tailgate is thus released from location apertured members which are fixed to the body.

Further operation of the rams causes the tailgate to be raised by pivoting upwardly in the usual way.

While this has the advantage of permitting the release of the tailgate by rapid and remote control power means, for example operated from the cab of the vehicle, it has the disadvantage that the sliding movement of the tailgate relative to the vehicle container body tends rapidly to wear out - the seals between the body and the tailgate.

Failure of the seals may permit the leakage of liquids from the refuse.

It is an object of the invention to provide a new or improved tailgate locking means primarily for a refuse collection and compaction vehicle of the type specified.

According to the invention there is provided tailgate locking means for a refuse collection and compaction vehicle of the type specified, comprising at least a first apertured member on the vehicle container body adjacent the base of the opening therein; at least a second apertured member on the tailgate adapted, in the normal closed condition of the tailgate, to lie closely adjacent to or abut the first apertured member so that the apertures are aligned; a spring loaded plunger means adapted to project through said aligned apertures to prevent movement of the tailgate relative to the body; and fluid operated piston and cylinder means which, on being actuated, act on the plunger means to withdraw it from said aligned apertures.

The "normal closed condition" of the tailgate is one in which the opening of the vehicle container body is closed by abutment of the tailgate, as distinct from the "raised" or "open" condition of the tailgate, in which it has been pivotally moved from the normal closed condition to reveal the opening of the container body.

The tailgate or the body may be provided with a third apertured member, the aperture of which is aligned with those of the first and second apertured members in the normal closed condition of the tailgate, the apertured members being so arranged that two spaced apart apertured members are provided either on the body or on the tailgate and the remaining apertured member is disposed between them in the normal closed condition of the tailgate.

Preferably, the second and third apertured members are provided spaced apart on the tailgate and the first apertured member is provided on the body.

The or each plunger means may be rigidly connected to the piston of the associated piston and cylinder assembly.

The invention also provides a refuse collection compaction vehicle having a tailgate locking means as set out above.

A locking means as set out above may be provided at each side of the tailgate.

Actuation of the piston and cylinder assembly or assemblies may be controlled by valve means associated with the control means of lifting rams of the tailgate, whereby the tailgate may firstly be unlocked and then lifted to the open condition by operation of a single control means.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: FIGURE 1 is a side elevational view of a refuse collection and compaction vehicle of the type specified having tailgate locking means embodying the invention; FIGURE 2 is a detail perspective view of the tailgate locking means of Figure 1.

Referring firstly to Figure 1 of the drawings, a refuse collection and compaction vehicle comprises a truck chassis 10 carrying a container body 11 which is provided at its rear end with an opening, the periphery of which is shown at 12 and which is inclined slightly to the vertical as shown.

A tailgate 1 3 is mounted on the container body by means of a pair of pivots 14 disposed at the top of the tailgate, one being provided at each side of the tailgate. The tailgate can be raised from the normal closed condition shown to a raised or open condition 1 5 shown in chain dotted outline, by the actuation of a pair of main lifting rams 1 6, symmetrically disposed at each side of the tailgate.

In the normal closed condition of the tailgate, the tailgate provides means for collecting and compacting refuse into the container body 11, and substantial reaction forces are therefore exerted on the tailgate. To prevent the tailgate lifting away from the periphery 12 of the opening in the container body, locking means generally indicated at 1 7 are provided to hold the tailgate in the normal closed condition except when it is specifically released.

Referring to Figure 2 of the drawings, the locking means 1 7 will be seen to comprise a first apertured member or bracket 1 8 rigidly secured to the container body 11, and second and third apertured members 1 9 and 20 respectively secured to the tailgate 1 3 at spaced positions. The arrangement is such that, when the tailgate is pivoted into the normal closed condition, the second and third apertured members 19 and 20 swing into place respectively above and below the first apertured member 1 8 on the body.

The apertures 21,22,23 of the apertured members 18, 19 and 20 respectively are all aligned in the normal closed condition of the tailgate 13 and a suitable rod-like plunger 24 extends through these aligned apertures to lock the tailgate to the body 1 The plunger 24 is rigidly secured to the piston 25 of a piston and cylinder assembly 26 which is either hydraulically or pneumatically operated. The piston and cylinder assembly is of a type having a working stroke in one direction which would tend to withdraw the plunger 24 from the aligned apertures 21, 22 and 23.

The piston and cylinder assembly has a powerful spring 27 housed within the assembly and acting on the piston, tending to return it in the direction which is the reverse of the power stroke of the piston. This return spring 27 therefore tends to force the plunger 24 into the aligned apertures 21,22 and 23.

It will be seen that, in order to unlock the tailgate, the piston and cylinder assembly has to be actuated, whereas the spring will normally hold the plunger in a position such as to lock the tailgate. The locking means 1 7 is therefore normally locked and needs to be positively unlocked to enable the tailgate 1 3 to be lifted.

On actuation of the piston and cylinder assembly to unlock the tailgate 13, the main lifting ram 16 can then be actuated to lift the tailgate to the dotted line condition 1 5. This movement from the normal closed condition to the raised or open condition is carried out by a straightforward pivoting about the pivots 1 4 and it will therefore be appreciated that negligble wear will occur on the seals 28 which are provided on the periphery 12 of the container body opening and on the corresponding abutting peripheral surface of the tailgate 1 3. These seals are normally held in compression by th weight of the tailgate when it is in its normal closed condition.Unlocking and raising the tailgate does not cause the seals 28 to slide relative to each other but merely causes them to pivot apart, resulting in a greatly improved life compared with seals which are subjected to friction under load in the previously known power operated locking arrangements referred to above.

It will be appreciated that the actuation of the piston and cylinder assemblies 26 to unlock the tailgate may be carried out by control means housed remote from the tailgate, for example in the cab of the truck 1 0. By the use of appropriate hydraulic valve arrangements, the same control means can be arranged sequentially to unlock the tailgate by actuating the piston and cylinder assemblies 26 and then raise the tailgate by actuating the main lifting ram 1 6. Alternatively, separate control means can be provided for the two operations.

Since the control means can be operated from the vehicle cab, only one operator is needed to unload the refuse vehicle at a tip or incinerator, and the operation can be performed very speedily and without undue effort.

The tailgate locking controls are also relatively tamper-proof, being housed in the cab as distinct from being accessible on the sides of the vehicle, which could result in their being accidentally or maliciously tampered with.

Claims (10)

1. Tailgate locking means for a refuse collection and compaction vehicle of the type specified, comprising at least a first apertured member on the vehicle container body adjacent the base of the opening therein; at least a second apertured member on the tailgate adapted, in the normal closed condition (as herein defined) of the tailgate, to lie closely adjacent or abut the first apertured member so that the apertures are aligned; a spring loaded plunger means adapted to project through said aligned apertures to prevent movement of the tailgate relative to the body; and fluid operated piston and cylinder means which, on being actuated, act on the plunger means to withdraw it from said aligned apertures.

2. Locking means according to Claim 1 wherein the tailgate or the body is provided with a third apertured member, the aperture of which is aligned with those of the first and second apertured members in the normal closed condition of the tailgate, the apertured members being so arranged that two spaced apart apertured members are provided either on the body or on the tailgate and the remaining apertured member is disposed between them in the normal closed condition of the tailgate.

3. Locking means according to Claim 2 wherein the second and third apertured members are provided spaced apart on the tailgate and the first apertured member is provided on the body.

4. Locking means according to any preceding claim wherein the plunger means is rigidly connected to the piston of the piston and cylinder assembly.

5. A refuse collection and compaction vehicle of the type specified having locking means according to any preceding claim.

6. A vehicle according to Claim 5 wherein a locking means is provided at each side of the tailgate.

7. A vehicle according to Claim 5 or Claim 6 wherein the tailgate is capable of being lifted by lifing rams and wherein the control valve means are provided which are arranged firstly to operate the or each piston and cylinder assembly to unlock the tailgate and then to operate said lifting rams to lift the tailgate to an open condition.

8. Tailgate locking means for a refuse collection and compaction vehicle of the type specified substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

9. A refuse collection and compaction vehicle of the type specified substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

10. Any novel feature or novel combination of features as hereinbefore described and/or illustrated in the accompanying drawings.