GB2131386A - Load handling vehicle - Google Patents

Abstract

A refuse collection vehicle has a pump (26) for supplying hydraulic fluid to rams (24, 25) of load handling apparatus of the vehicle. The pump is driven whenever an engine (14) of the vehicle is running. A by-pass valve between an outlet and an inlet of the pump can be closed by a signal from a push-button operated switch mounted at the rear of the vehicle. The valve is subsequently opened by a signal produced automatically at the end of a cycle of operation of the load-handling apparatus. <IMAGE>

Description

SPECIFICATION Load handling vehicle This invention relates to a motor vehicle having a body suitable for carrying a load and load handling apparatus for use in loading or unloading the body, the load handling apparatus including at least one hydraulic motor which can be supplied with hydraulic fluid from a pump associated with an internal combustion engine of the vehicle. The invention has been developed primarily in connection with refuse collection vehicles and the application of the invention to such vehicles will be described hereinafter. However, the invention may be applied to other load handling vehicles where analogous requirements arise.

Known load handling vehicles have a driver's cab in which there is provided a manually operable control element for setting in a selected one of operative and inoperative conditions the hydraulic pump associated with the internal combustion engine of the vehicle. In one known arrangement, the control element is adapted to move into or out of mesh elements of a gear train through which torque can be transmitted from the internal combustion engine to the pump. In another known arrangement, the pump is driven continuously when the internal combustion engine is running, and is provided with a by-pass valve through which hydraulic fluid can flow directly from an outlet of the pump to an inlet of the pump. The control element in the driver's cab is an eiectric switch or part of a linkage operatively associated with the by-pass valve.By manipulation of the control element, the driver can close the by-pass valve, thereby setting the pump in an operative condition, in which it can deliver hydraulic fluid to the load handling apparatus of the vehicle.

The load handling apparatus of a vehicle of the kind hereinbefore described is normally required to operate intermittently. It has been found that the load handling apparatus can be controlled more conveniently and safely by use of a second control element outside the driver's cab in conjunction with the control element in the driver's cab, than is the case when operation of the load handling apparatus is controlled solely by means of a control element within the driver's cab.

The further control element is generally mounted adjacent to the load handling apparatus.

Thus, known refuse collection vehicles having load handling apparatus for lifting and tipping bins and/or load handling apparatus for packing refuse into a body of the vehicle usually have, in addition to the control element within the driver's cab, a further control element at the rear of the vehicle.

By operation of the further control element, whilst the hydraulic pump is in an operative condition, a cycle of operation of the load handling apparatus can be initiated.

According to a first aspect of the present invention, there is provided a motor vehicle having a body for carrying a load, load handling apparatus including an hydraulic motor, an hydraulic pump associated with an internal combustion engine of the vehicle to be driven thereby and adapted to deliver hydraulic fluid to the motor and a driver's cab, wherein there is provided outside the driver's cab of the vehicle a manually operable control element by means of which an operator can set the hydraulic pump in an operative condition and can initiate operation of the load handling apparatus.

The load handling apparatus is preferably adapted to operate cyclically and includes a second control element which is operated automatically at the end of a cycle of operation to terminate operation of the load handling apparatus and to set the hydraulic pump in its inoperative. condition.

An example of a motor vehicle embodying the invention will now be described, with reference to the accompanying drawings, wherein: FIGURE 1 illustrates diagrammatically a side elevation of the vehicle; FIGURE 2 illustrates diagrammatically a rear elevation of the vehicle; and FIGURE 3 is a diagram of an hydraulic, pneumatic and electrical circuit of the vehicle.

The vehicle illustrated in the drawing has a chassis 10 on which are mounted steerable front wheels 11 and drivable rear wheels 12. Adjacent to a front end of the chassis is a driver's cab 1 3 and below the cab there is mounted an internal combustion engine 14. A transmission (not shown) is provided for transmitting torque from the engine 1 4 to the rear wheels 12.

On the chassis 10, there is mounted a body 1 5 defining a hopper 16 adjacent to the rear end of the vehicle and a compartment 17 which is large, as compared with the hopper, and in which material is transported by the vehicle. Load handling apparatus is provided for transferring into the compartment 1 7 material which is placed in the hopper 1 6. The vehicle may be used for the collection of refuse and refuse bins may be emptied into the hopper 1 6 manually.

The load handling apparatus includes a carrier 1 8 supported in rectilinear guides 1 9 mounted on side walls of the body 1 5 so that the carrier can be reciprocated from an upper position in a direction inclined downwardly and rearwardly to a lower position. For moving the carrier between its upper and lower positions, there is provided a pair of hydraulic rams 20 and 21.

There is mounted on the carrier 1 8 for pivoting relative thereto about an axis 22 which extends transversely of the vehicle a sweeping member 23. A further pair of hydraulic rams, 24 and 25 is provided for pivoting the member 23 relative to the carrier. When the carrier 18 is in its lower position, pivoting of the member 23 relative to the carrier causes the member to sweep a concave surface of the hopper and transfer material resting on that surface into the compartment 17. When the carrier 1 8 is in its upper position, pivoting of the member 23 relative to the carrier does not disturb material resting on the concave surface of the hopper.

For supplying hydraulic fluid under pressure to the rams of the load handling apparatus, there is provided an hydraulic pump 26 which is mounted on the engine 1 4 to be driven thereby. In the particular arrangement illustrated, the pump 26 is driven whenever the engine 14 is running.

The pump has an inlet connected with a reservoir 27 (shown in Figure 3) and has a by-pass valve 28 connected between an outlet of the pump and the inlet of the pump or the reservoir.

When the by-pass valve 28 is open, the pump is in an inoperative condition and does not supply hydraulic fluid to the load handling apparatus. The valve 28 can be closed by the establishment of pressure in an associated air cylinder 29, the pump then being in an operative condition and capable of supplying hydraulic fluid under pressure to the load handling apparatus.

There is also provided on the vehicle an air reservoir 30 which is pressurised by means of a compressor (not-shown) also driven by the engine 14. There is associated with the air cylinder 29 a solenoid-operated valve 31 through which air can be admitted from the reservoir 30 to the air cylinder 29 and through which the air cylinder 29 can be vented to atmosphere.

The load handling apparatus includes a further pneumatically operated valve 32 which controls flow of hydraulic fluid from the pump 26 to the rams and from the rams to the reservoir 27. Flow of hydraulic fluid to the rams 20 and 21 is controlled by a mechanically actuated valve 33 and flow of hydraulic fluid to the rams 24 and 25 is controlled by a further mechanically actuated valve 34.

The valve 33 is mounted on the carrier 1 8 or on a part which moves with the carrier and is arranged to be operated by a striker mounted on the sweeping member 23. The valve is settable in a selected one of two conditions by the striker. In the first of these conditions, which is adopted when the sweeping member reaches the limit of its downwards and forwards pivoting movement relative to the carrier, the valve 33 normally directs hydraulic fluid from the valve 32 to the rams 20 and 21 so that these rams are contracted.

The valve 34 is mounted on a part which is fixed with respect to the body 1 5 and is operated by a striker mounted on the carrier 1 8. The valve 34 can be set by the striker in a selected one of two alternative conditions. In a first of these conditions, which is adopted when the carrier 1 8 reaches its uppermost position, the valve 34 normally directs hydraulic fluid from the valve 32 to the rams 24 and 25 so as to retract these rams and pivot the sweeping member 23 rearwardly and upwardly on the carrier.

A further valve 35 is mounted on the carrier 18 or a part which moves with the carrier for actuation by a further striker which moves with the sweeping member 23. This further valve is settable in a selected one of two conditions, in a first of which it provides a path for flow of fluid between the rams 24 and 25 and the valve 34. In its second condition, the valve 35 is closed but flow in one direction past the valve 35 can be permitted by a check valve 36.

For controlling operation of the load handling apparatus, there is mounted on the body 1 5 at the rear of the vehicle signalling means whereby an operator can provide signals to the valve 32 and to the by-pass valve 28 to establish the pump 26 in a condition in which it supplies hydraulic fluid to the valve 32 and to open the valve 32, thereby directing hydraulic fluid to the rams of the load handling apparatus.In the particular example illustrated, these signals are electrical and pneumatic in nature, the control panel 37 having three push buttons associated with respective electrical switches 40,41,42 (Figure 3) which control the supply of electrical current to the solenoid-operated valve 31 and to further solenoid-operated valves 38, 39 which control the application of pneumatic pressure to and venting of air cylinders operatively associated with the valve 32. A brief electrical signal from the control panel 37 is sufficient to establish in the air cylinders associated with the valves 31 and 32 pressure which is sufficient to operate these valves and subsequently to maintain the valves in the conditions to which they have been set, notwithstanding that energisation of the solenoidoperated pneumatic vales is discontinued.

One push button on the panel 37 provides an electrical signal to the solenoid valves which brings about venting of the air cylinders associated with valves 28 and 32, so that operation of the load handling apparatus is immediately discontinued. A third push button on the control panel can be used to provide a signal to the valve 32 in order to reverse the connections between the load handling apparatus on the one hand and the pump 26 and reservoir 27 on the other hand, so that movement of the carrier 18 and sweeping member 23 is reversed. The control panel 37 may be duplicated at opposite sides of the vehicle body.

Normal operation of the load handling apparatus is initiated by operation of one push button to provide a brief signal from switch 41 which sets the pump 26 in an operative condition and sets the valve 32 in an open condition. At the beginning of a cycle of operation of the load handling apparatus, the valves 33, 34 and 35 are in the conditions shown in Figure 3. Hydraulic fluid flows from the pump through valves 32, 34 and 35 to the rams 24 and 25 to retract these rams.

During retraction of these rams, the pressure of hydraulic fluid applied through valve 33 to the rams 20 and 21 maintains these rams in a retracted condition.

Retraction of the rams 24 and 25 pivots the sweeping member 23 upwardly and rearwardly on the carrier 1 8 to a position which is pre-selected by adjustment of the positions of the strikers which operated valves 33 and 35. The full travel of rams 24 and 25 would not normally be used, in order that the sweeping member 23 should not rise above what is considered to be a safe level.

When the sweeping member reaches the selected position, the conditions of valves 33 and 35 are changed by their strikers. Valve 33 then directs hydraulic fluid to the rams 20 and 21 so as to extend these rams and move the carrier 1 8 downwardly and rearwardly relative to the body 1 5. During this movement of the carrier 18, extension of the rams 24 and 25 is prevented by the valves 35 and 36.

A check valve is provided in the line between valve 33 and those end portions of the cylinders 20 and 21 from which hydraulic fluid is expelled when the cylinders extend. This check valve prevents extension of these cylinders when there is no substantial pressure in the hydraulic circuit, for example when the valve 32 is closed and the pump 26 is in the inoperative condition. When substantial hydraulic pressure is applied to the opposite ends of the rams 20 and 21, the valve 40 is opened so that fluid can leave the rams and the rams can extend.

When the carrier 1 8 reaches its lower position, the condition of valve 34 is changed by its striker so that hydraulic fluid is directed to the rams 24 and 25 to extend these rams, hydraulic fluid leaving these rams through the check valve 36.

Thus, the sweeping member 23 is pivoted downwardly and forwardly relative to the carrier 18 until it reaches the limit of its travel. As this limit is reached, the conditions of valves 33 and 35 are changed by their strikers and hydraulic fluid is directed by the valve 33 to the rams 20 and 21 so as to contract these rams and move the carrier 1 8 upwardly and forwardly relative to the vehicle body, thereby transferring material from the hopper 1 6 into the compartment 1 7. As the carrier 1 8 reaches its upper position, it operates an electrical limit switch 43 mounted on the body 1 5 and this limit switch provides an electrical signal to a solenoid-operated valve 39 associated with the valve 32 and the valve 28. The air cylinder associated with the valve 32 is vented to atmosphere, thus permitting this valve to close automatically and the air cylinder 29 also is vented to atmosphere, thus permitting the pump 26 to assume its inoperative condition automatically.

The limit switch 43 may be connected in series with a further limit switch (not shown) operated when the sweeping member reaches the limit of its pivoting movement in the downwards and forwards direction so that the pump 26 is set in its inoperative condition only when both the carrier 1 8 and sweeping member 23 have reached the positions in which they are normally parked whilst material is emptied into the hopper 16.

Claims (5)

1. A vehicle having a body for carrying a load, load handling apparatus including an hydraulic motor, an hydraulic pump associated with an internal combustion engine of the vehicle to be driven thereby and adapted to deliver hydraulic fluid to the motor and a driver's cab, wherein there is provided outside the cab of the vehicle a manually operable control element by means of which an operator can set the hydraulic pump in an operative condition and can initiate operation of the load handling apparatus.

2. Apparatus according to Claim 1 wherein a single operation of the control element sets the hydraulic pump in the operative condition and initiates operation of the load handling apparatus.

3. Apparatus according to Claim 1 or Claim 2 comprising a further control element which is operated automatically by the load handling apparatus at the end of a cycle of operation of same to set the hydraulic pump in the inoperative condition.

4. A vehicle substantially as herein described with reference to and as shown in the accompanying drawing.

5. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawing.