GB2138386A

GB2138386A - Refuse collection vehicle

Info

Publication number: GB2138386A
Application number: GB08410132A
Authority: GB
Inventors: Manus Coffey; Norman Slack
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-04-20
Filing date: 1984-04-18
Publication date: 1984-10-24
Also published as: GB2138386B; IE830901L; GB8410132D0; IE54185B1

Abstract

A refuse collection vehicle comprises a refuse collection unit 10 mounted on the vehicle chassis behind the driver's cab 12, the refuse collection unit including a hollow main body portion 13 constituting a refuse collection chamber, and a paddle-type compactor 14 at the front end of the main body portion 13 behind the cab 12 for receiving refuse and forcing it rearwardly into the chamber. A refuse discharge opening 19 is provided at the rear of the main body portion 13, and a tipping mechanism discharges refuse from the chamber through the discharge opening 19 by raising the front end of the main body portion relative to the rear end. <IMAGE>

Description

SPECIFICATION Refuse collection vehicle This invention relates to a refuse collection vehicle.

Compaction-type refuse collection vehicles may be broadly classified into three kinds - rear loaders, side loaders and front loaders. Rear loaders have the disadvantage that the compaction mechanism must be moved out of the way before the collected refuse can be discharged in the usual way by tipping the front end of the vehicle body upwardly relative to the rear. In larger vehicles this necessitates a complex and therefore expensive lifting mechanism, and in all such vehicles the rear compactor provides an undesirable weight distribution. Side loaders have a relatively small capacity since the compaction mechanism is contained within the main refuse collection chamber of the vehicle; furthermore they are not capable of continuous loading but rather alternate loading and compaction operations.Front loaders conventionally use dual purpose rams for compaction and for discharge, and also do not permit continuous loading.

It is therefore an object of the present invention to provide a compaction-type refuse vehicle which avoids the abovementioned disadvantages yet which can be constructed at low cost.

Accordingly, the present invention provides a refuse collection vehicle in which a refuse collection unit is mounted on the vehicle chassis behind the driver's cab, the refuse collection unit including a hollow main body portion constituting a refuse collection chamber, a paddle-type compactor at the front end of the main body portion behind the driver's cab for receiving refuse and forcing it rearwardly into the chamber, a refuse discharge opening at the rear of the main body portion, and a tipping mechanism for discharging refuse from the chamber through the said discharge opening by raising the front end of the main body portion relative to the rear end.

It is to be understood that the term paddle-type compactor as used herein refers to a device including a bin or hopper having a generally semi-circular sidewall and an opening communicating with the chamber in the main body portion of the unit, and a vane- or paddle-like member mounted for reciprocation to and fro about an axis substantially concentric with the sidewall so as to sweep refuse placed in the hopper through the hopper opening into the chamber. A compactor of this general kind is described in UK Patent Specification 1 032 920 although, as will be described, the design of compactor used in the preferred embodiment of the present invention differs from this earlier design.

The invention has several advantages compared to the prior art referred to above. Since the compactor is placed at the front end of the main body portion, between the latter and the cab, the tipping mechanism can be operated to empty the refuse collection chamber without moving the compactor out of the way which is necessary with rear loaders.

This location for the compactor also provides a good weight distribution. The use of a "low weight" vehicle in comparison with standard refuse collection vehicles increases the refuse payload which may be carried since the maximum permitted carrying capacity is determined by the aggregate of the vehicle weight and refuse payload. Hence the lower the vehicle weight the greater the allowable refuse payload. Also, since the compactor is small and located externally of the refuse chamber, for a given overall size of vehicle the capacity of the refuse chamber may be increased as compared with sideloaders whose compaction system is contained within the chamber. Furthermore, a paddle-type compactor is cheap compared to the conventional front loader mechanism and it permits substantially continuous loading.It is envisaged that the relatively high capacity combined with good weight distribution and low cost permit the invention to be implemented by mounting a refuse collection unit as defined above on a standard small truck chassis.

In the preferred embodiment the compactor drive mechanism uses two fluid-operated cylinders which act by retraction and are operated alternately each to drive the paddle in a respective direction of rotation in the hopper, the mechanism including a linkage coupling each cylinder to the paddle such that during the initial stage of each stroke of the paddle the torque exerted on the paddle is low but increases progressively as the paddle approaches the end of its stroke.

It is envisaged that the compactor with the improved drive mechanism as above may have utility in applications other than refuse collection vehicles, and therefore constitutes an invention per se.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a refuse collection vehicle according to the invention, Figure 2 is a side view of the vehicle of Figure 1, Figure 3 is a side view of the vehicle in its discharge position, and Figures 4 to 6 illustrate the compactor drive mechanism in top plan view at successive stages of compaction.

Referring first to Figures 1 to 3, the refuse collection vehicle comprises a refuse collection unit 10 mounted on the chassis 11 of a truck behind the driver's cab 12. The unit 10 includes a hollow main body portion 13 constituting the refuse collection chamber, and a paddle-type compactor 14 at the front end of the main body portion 13 behind the cab 12.

The compactor 14 comprises an upwardly and rearwardly inclined hopper 15 with a semi-circular sidewall 16, and a paddle 17 pivotally mounted on a fixed shaft 18 for reciprocating motion in the hopper 15 about an axis concentric with the sidewall 16. As will be described with reference to Figures 4 to 6, the paddle, which pivots on the shaft 18, is driven by two hydraulic retraction cylinders and serves the sweep refuse placed into the hopper 15 through a rear hopper opening into the chamber constituted by the body portion 13.

The unit 10 further includes an upwardly and forwardly inclined refuse discharge opening 19 at the rear of the main body portion 13, the opening normally being closed by a rear door 20 freely hinged at the top 21. In order to discharge refuse from the refuse collection chamberthrough the opening 19, the front end of the unit 10 is pivotted upwardly about a point 22 on the chassis 11 adjacent the rear end of the body portion 13, Figure 3, this being accomplished by a tipping ram 23 in conventional manner. During such tipping the rear door 20 is released at the bottom so as to swing open under gravity as shown.

Referring now to Figures 4 to 6, the drive mechanism for the compactor is contained in a housing 30 located below the hopper 15 (see also Figures 2 and 3), and drives a hollow shaft 18a which is pivotally mounted on the fixed shaft 18 and to which shaft 18a the paddle 17 is non-rotatably secured. The shaft 18a is concentric with the shaft 18 and with the hopper sidewall 16 and is mounted for rotation in conventional bearings (not shown) on the shaft 18. One bearing is mounted on the shaft end at the base of the housing 30 and the other bearing is mounted at the shaft end on the underside of a beam 31, which extends diametrically across the hopper closely adjacent the top of the sidewall 16.

The drive mechanism includes two hydraulic cylinders 32,33 which operate in retraction, a forked radial crank member 34 non-rotatably secured to the shaft 18a, and a pair of short link arms 35,36 which respectively couple the piston rods 37,38 of the cylinders 32,33 to the crank member 34. In particular, the cylinders 32,33 are pivotted at 39,40 to a rigid frame member 41 secured at one side of the housing 30, and their piston rods 37,38 are pivotted at 42,43 to the free outer ends of the link arms 35,36 respectively, the inner ends of the link arms 35,36 being pivotted at 44,45 to respective forked ends of the crank member 34.

In operation the paddle 17 reciprocates to and fro through about 2109 between the end position shown in Figure 4 and an end position symmetrical therewith on the opposite side of the hopper 15. Each stroke of the paddle 17 in the clockwise direction (as viewed in Figures 4 to 6) is effected by retraction of the cylinder 33, whereas the return stroke is effected by retraction of the cylinder 32. The retraction stroke of the cylinder 33 will now be described, starting at the paddle end position shown in Figure 4; i.e. a clockwise stroke of the paddle will be described.

In the end position shown in Figure 4, the link member 36 engages around and behind the crank member 34 from the pivot point 43 to the pivot point 45, and abuts against the shaft 18a by means of a part circular indentation 50 conforming to the circular periphery of the shaft. Thus in the initial stages of retraction of the cylinder 33 the torque on the shaft 18a which is a function of the perpendicular distance between the axis of the shaft 18a and the line of action ofthe cylinder 33, is low and the rotationai speed of the paddle 17 is relatively high. This is acceptable since at this stage the refuse is loose in the hopper 15 and little force is needed to sweep it ahead ofthe paddle 17.

In the mid-position of the paddle 17, shown in Figure 5, the link member 36 is still in abutment against the shaft 18a. The torque is therefore still low and the fast movement of the paddle is maintained.

Beyond this point, however, the link member 36 comes out of abutment with the shaft 18a and the perpendicular distance between the axis of the shaft 1 8a and the line of action of the cylinder 33 progressively increases. The torque therefore also progressively increases with a corresponding progressive decrease in the paddle speed. This is necessary as from the mid-position onward the refuse becomes increasingly compacted and thus an increasing compaction force is necessary to continue the forward sweep of the paddle. This can only be achieved by increasing the torque if it is assumed that the retraction force exerted by the cylinder 33 remains substantially constant.

Maximum torque, and hence maximum compaction force, is achieved at the position shown in Figure 6 where the paddle 17 is approaching its opposite end position, and where the pivot 45 lies on the line of action of the cylinder 33 (i.e. the pivot points 40,43 and 45 are co-linear and a line through the centred point of the shaft 18 and the pivot point 45 is at 90" to the line 40,43,45). Beyond this position the torque decreases slightly, but remains sufficiently high to push the compacted refuse into the chamber in the main body portion 13 via an opening (not shown) extending diametrically across the width of the hopper 15 between the base of the latter and the underside of the beam 31.

The operation of the mechanism for the return stroke of the paddle 17 to the position shown in Figure 4 is similar to that forthe forward stroke described above, except that the torque is now exerted by the retraction cylinder 32 via the link member 35. The characteristic of low initial torque with progressively increasing torque form the midposition on is achieved in the same way as for the forward stroke, since the drive mechanism for the shaft 18 is symmetrical as regards the arrangement of cylinders 32,33 and link members 35,36 as can be seen in particular in Figure 5.

The advantage of the above mechanism is that each cylinder 32,33 operates only in retraction, and only one cylinder is used in each direction of stroke of the paddle 17. Thus the mechanism is simple to control, since all that is required is a single reversible valve, for example solenoid-operated, which supplies hydraulic fluid alternately to one and then the other cylinder in turn. The switchover of the valve is effected automatically when each cylinder reaches the end of its stroke, or alternatively as a safety measure by a pressure switch in the hydraulic circuit when the force on the paddle 17 becomes too high for the cylinder currently in retraction. It will be understood that the hydraulic circuit which drives the cylinders 32,33 may be quite conventional and therefore details are not thought necessary.

Claims

1. A refuse collection vehicle in which a refuse collection unit is mounted on the vehicle chassis behind the driver's cab, the refuse collection unit including a hollow main body portion constituting a refuse collection chamber, a paddle-type compactor at the front end of the main body portion behind the driver's cab for receiving refuse and forcing it rearwardly into the chamber, a refuse discharge opening atthe rear of the main body portion, and a tipping mechanism for discharging refuse from the chamber through the said discharge opening by raising the front end of the main body portion relative to the rear end.

2. A refuse collection vehicle according to claim 1, wherein the paddle-type compactor has a drive mechanism including two fluid-operated cylinders which act by retraction and are operated alternately each to drive the paddle in a respective direction of rotation, the mechanism including a linkage coupling each cylinder to the paddle such that during the initial stage of each stroke of the paddle the torque exerted on the paddle is low but increases progressively as the paddle approaches the end of its stroke.

3. A refuse collection vehicle according to claim 2, wherein the paddle is non-rotatably secured to a shaft which is driven for reciprocation by the said cylinders via a radial crank, each cylinder being pivotted to the radial crank by a respective link member which at the beginning of a paddle stroke engages around and behind the shaft to provide a low torque on the paddle but which comes out of engagement with the shaft during the paddle stroke to increase the torque on the paddle.

4. A refuse collection vehicle substantially as described herein with reference to the accompanying drawings.