GB2116620A

GB2116620A - Asphalt kerbing machine

Info

Publication number: GB2116620A
Application number: GB08304610A
Authority: GB
Inventors: Willis Arnold Charlesworth
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-02-27
Filing date: 1983-02-18
Publication date: 1983-09-28
Also published as: GB8304610D0; GB2116620B

Abstract

An asphalt kerb extruding machine 1, comprises a wheeled chassis 2, a power unit mounted on the chassis 2, a bulk asphalt receiving hopper 8 mounted on the chassis 2, an auger 10 located at the bottom of the hopper 8 to compact the asphalt and to feed asphalt to a receiving end of a mould 17 of the required kerb cross-section, a hydraulic drive 13 to the auger, a hydraulic drive to at least two, laterally spaced road wheels 3 of the chassis 2 and a hydraulic connection between the auger drive 13 and the road wheel drive, such that the latter is inoperative until a predetermined fluid pressure has been attained in the auger drive 13. <IMAGE>

Description

SPECIFICATION Asphalt kerbing machine This invention relates to an asphalt kerbing machine adapted to extrude an asphalt kerb from a mould of suitable section.

Known asphalt kerbing machines comprise a wheeled chassis having a hopper to receive bulk asphalt, with a power driven asphalt compaction auger at the bottom of the hopper, to feed asphalt into a receiving end of a mould to form the asphalt to the required kerb cross-section, a range of moulds being attachable to the machine to provide for a range of differing kerb cross-sections.

The auger is driven mechanically e.g. through a speed reduction gearbox, the chassis carrying an adjustable speed power unit e.g. a petrol or diesel engine connected either to the gearbox or alternatively to a hydraulic pump.

Such machines are self-advancing in that the auger reacts on the kerb being extruded to push the machine forwards. It will be appreciated that whilst consistency of asphalt composition, asphalt temperature and kerb cross-section would be ideal, in practice this rarely occurs, while ambient temperature vary considerably even in the U.K., between summer and winter conditions. The result is that from time to time the machines will not advance at the appropriate rate -- advance may be too slow if the asphalt is too loose or too rapid if the asphalt is too thick - with a result that an unacceptable kerb is extruded e.g. having blow holes, drag marks, or being sausage like instead of having a regular cross-section.

In another known machine for forming kerbs of concrete, no auger is present, the cross-section of the kerb being produced by a slip-forming technique with a mould sliding over concrete as a latter is progressively loaded, and vibrated, at a receiving end of the mould.

According to the present invention there is provided an asphalt kerb extruding machine comprising a wheeled chassis, a power unit mounted on the chassis, a bulk asphalt receiving hopper mounted on the chassis, an auger located at the bottom of the hopper to compact the asphalt and to feed asphalt to a receiving end of a mould of the required kerb cross-section, a hydraulic drive to the auger, a hydraulic drive to at least two, laterally spaced, road wheels of the chassis, and a hydraulic connection between the auger drive and the road wheel drive such that the latter is inoperative until a predetermined fluid pressure has been attained at the auger drive.

Thus, the machine in accordance with the invention enables machine advance to be restrained until such time as the attainment of the predetermined fluid pressure indicates that the auger is operating to produce extruded kerbs of acceptable quality i.e. when the asphalt has attained the requisite density to form an acceptable kerb. It has been shown that the machine in accordance with the invention is able to accept a wider range of asphalt mixes, over wider temperature ranges, and for a wider range of kerb sections.

Preferably the two drive wheels each have an individual hydraulic motor to avoid departures from the undesired path of machine advance e.g.

in situations where the two road wheels become located at different levels. It is also preferred for the chassis to incorporate a reservoir for the hydraulic fluid. The auger may feed asphalt into a compaction tube upstream of the mould, so that the compaction tube discharges into the inlet end of whatever mould has been fitted to the machine for the kerb cross-section required.

Conveniently the hydraulic circuit incorporates a flow divider valve to split the pressure fluid equally between the two road wheels. It is also preferred for a fluid supply line from the pump to the auger motor to have tapped into it a connection to an adjustable pressure sensing valve that may be set and adjusted by the operator to open at a predetermined fluid pressure (i.e.

when the operator is satisfied that the auger is compacting asphalt to an acceptable density), adjustment being effected in accordance with the prevailing operating conditions. Downstream of the pressure sensing valve an adjustable, flow control valve is preferably provided to ensure a finer control of the volume of fluid being passed through the pressure sensing valve, and with pressure fluid passing from the flow control valve to the flow divider. It is also preferred for the machine to incorporate means to put the drive wheels into a free-wheeling condition should the extrusion be effected under optimum conditions.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side elevation of a machine in accordance with the invention; Figure 2 is an end elevation of Figure 1, and Figure 3 is a hydraulic circuit for use with the machine of Figures 1 and 2.

In the drawings, an asphalt kerb extruding machine 1 comprises a chassis 2 provided with a pair of leading wheels 3 (in the direction of travel of the machine 1), and a pair of trailing wheels 4, the wheels 3 and 4 engaging a road surface 5 onto which a kerb 6 is to be extruded.

The chassis 2 carries at its leading end a power unit e.g. in the form of a diesel engine enclosed in a casing 7, and also carries a bulk, asphalt receiving hopper 8 having at its upper end a loading hatch 9 and at its lower end an auger 10 having a drive shaft 11 passing out of the hopper and rotatably supported in bearings 1 2 beyond which is a hydraulic motor 13 which receives hydraulic fluid from a hydraulic pump (not shown in Figure 1 and 2) also carried by the chassis 2, and driven by the prime mover, the pump taking hydraulic fluid from a reservoir tank 14 located at the trailing end of the chassis 2, and the various pressure and exhaust hoses being omitted for clarity.The motor 1 3 drives the shaft 11 and hence the auger 10, the latter having an extension 1 5 into a compaction tube 16 located upstream of a mould 1 7, the latter being readily attachable, and detachable from, the machine 1, and in particular the compaction tube 1 5, to enable ready replacement of moulds 1 7 of different internal cross-sectional shapes to provide a capacity to vary the kerb cross-section being extruded.

The wheel 3 constitute drive wheels and are each provided with an individual hydraulic motor 13a, while the chassis 2 isadjustable with respect to the wheels 3 and hence the mould 17 is adjustable with respect to the road surface 5 by interposing adjusting means 18, e.g. in the form of rams or screws, between the chassis 2 and each wheel 3. At the trailing end of the chassis 2, the wheels 4 are connected to the chassis 2 via hydraulic adjusting rams 19, which may be used for adjustment but which are primarily for assisting the loading of the machine 1 onto a transportation trailer.

Considering now the hydraulic circuit shown in Figure 3, the pump 20 extracts hydraulic fluid along a line 21 from the reservoir tank 14, the fluid being first passed through a suction filter 22 before reaching the pump 20, pressurised fluid being passed along line 23 and thereafter along line 24, through a pressure filter 25 to the hydraulic motor 13. A relief valve 26 is located in a line 27 to return fluid to the tank 14 via a line 28, should the relief setting pressure of valve 26 be exceeded. After passage through the motor 13, fluid is exhausted to tank 14 along a line 29 via a 30 p.s.i. check valve 30.A line 31 is tapped into the line 24 between the pressure filter 25 and the motor 13, the line 31 incorporating an adjustable sequence valve 32 to sense fluid pressure in the motor 1 3. When a predetermined pressure is attained in motor 13, pressure fluid is allowed to flow along line 31, flow being along lines 33 and 34, line 33 actuating a pressure operated by-pass valve 35, and line 34 incorporating a flow control valve 36, which is manually adjustable for setting the drive speed of the wheels 3. Beyond the valve 36, the line 34 incorporates a flow divider 37, to divide the flow into lines 38 and 39, one leading to each of the hydraulic motors 1 3a of the drive wheels 3, exhaust fluid from the motors 1 3a being passed along lines 40 and 41 are through the valve 35 back to the tank 14.

Therefore, supply of hydraulic fluid along the lines 31,33 and 34 to the wheel motors 1 3a is prevented by the setting of the sequence valve 32, until such time as an appropriate pressure buildup in the auger drive motor 13, line 24 and line 31 is indicative that asphalt at the required density is being compacted by the auger 10, and its extension 15, in the compaction tube 16, to provide an acceptable kerb, in the prevailing ambient conditions, and it follows that to a large extent, the setting of the sequence valve 32 is a question of operator experience and observation of the kerb quality being extruded at the start-up of extrusion operations.

In order to provide a free wheeling condition of the motors 13a, a line 42 is tapped into the line 29, the line 42 incorporating an adjustable, flow control valve 43, in order to throttle the amount of fluid being taken from the line 29, and a filter 44, fluid being passed from line 42 along lines 45 and 46 to the motors 1 3a and then along lines 47 and 48 via a 10 p.s.i. check valve 49 to the tank 14, whereby the 10 p.s.i. pressure in lines 47 and 48 maintains the motors 1 3a in a free-wheeling mode.

Claims

1. An asphalt kerb extruding machine comprising a wheeled chassis, a power unit mounted on the chassis, a bulk asphalt receiving hopper mounted on the chassis, an auger located at the bottom of the hopper to compact the asphalt and to feed asphalt to a receiving end of a mould of the required kerb cross-section, a hydraulic drive to the auger, a hydraulic drive to at least two, laterally spaced, road wheels of the chassis, and a hydraulic connection between the auger drive and the road wheel drive such that the latter is inoperative until a predetermined fluid pressure has been attained at the auger drive.

2. A machine as claimed in Claim 1 wherein the two drive wheels each have an individual hydraulic motor to avoid departures from the desired path of machine advance.

3. A machine as claimed in Claim 1 or Claim 2, wherein the chassis incorporates a reservoir for the hydraulic fluid.

4. A machine as claimed in any preceding Claim, wherein the auger feeds asphalt into a compaction tube upstream of the mould, so that the compaction tube discharges into the inlet end of whatever mould has been fitted to the machine for the kerb cross-section required.

5. A machine as claimed in any preceding Claim, wherein the hydraulic circuit incorporates a flow divider valve to split the pressure fluid equally between the two road wheels.

6. A machine as claimed in any preceding Claim, wherein a fluid supply line from the pump to the auger motor has tapped into it a connection to an adjustable pressure sensing valve that may be set and adjusted by the operator to open at a predetermined fluid pressure, adjustment being effected in accordance with the prevailing operating conditions.

7. A machine as claimed in Claim 6, wherein downstream of the pressure sensing valve an adjustable, flow control valve is provided to ensure a finer control of the volume of fluid being passed through the pressure sensing valve, and with pressure fluid passing from the flow control valve to the flow divider.

8. A machine as claimed in any preceding Claim, comprising means to put the drive wheels into a free-wheeling condition should the extrusion be effected under optimum conditions.

9. A machine as claimed in any preceding Claim, substantially as hereinbefore described with reference to the accompanying drawings.