WO1990002843A1

WO1990002843A1 - Material spreader

Info

Publication number: WO1990002843A1
Application number: PCT/AU1989/000390
Authority: WO
Inventors: John Giarratana
Original assignee: John Giarratana
Priority date: 1988-09-12
Filing date: 1989-09-12
Publication date: 1990-03-22

Abstract

A material spreader is provided, suitable for distributing aggregative materials such as concrete or crushed rock over an area of ground. The spreader (1) comprises an elongate trough (2) with a supply region into which material may be loaded, the trough also being provided with at least one delivery aperture (8) through which the material is spread, the spreader further comprising distributing means (6) preferably a shaft fitted with helical flights, for distributing the loaded material in a direction along the length of the trough so that the material may be spread from that part of the aperture (8) which is remote from the supply region. The spreader may be fitted with wheels (4) and rendered mobile in a direction perpendicular to the length of the trough. Also the trough may be constructed in removable multiple panels (15) so that its length may be varied; and the length of the delivery aperture (8) along the trough may be variable. A preferred embodiment provides for the connection of a hose pipe (30) and pump (32, 33, 34) to the trough so as to pump material therefrom in use.

Description

MATERIAL SPREADER

The present invention relates to a material spreader for spreading materials over a surface. It finds particular application in the field of building, for spreading materials such as concrete or crushed rock over an area of ground.

It is often necessary to spread a layer of material over a surface and, particularly in building, it may be desirable that the material should be laid evenly and to a specified depth. For instance, it may be required to lay a concrete area suitable for parking or walking on. This may be done by a truck delivering a load of premized concrete which is then spread manually over the area concerned before being levelled by a vibrating screeder. However, the spreading is a time-consuming and labour intensive process which often has additional problems such as difficulty of access for the truck delivering the concrete which may be over wet and boggy ground.

Further, it is often the case that the concrete being spread is to be reinforced concrete on a bed of crushed rock. This means that reinforcing elements such as wires will be extended over a prepared area of crushed rock where the concrete is to lie. If a truck delivers concrete to that area, as described above, the concrete must then be spread manually before being levelled. Both to spread it, and to operate the vibrating screeder, operators must walk on the bed of crushed rock with the reinforcing wires already extended over it. Inevitably, the wires tend to become displaced which is undesirable. In particular, the level of the wires in the finished concrete tends to be too low.

An object of the present invention is to provide a material spreader which can receive materials such as building materials and distribute them over an area in a convenient and advantageous manner.

According to the present invention, there is provided a material spreader comprising an elongate, trough having a material supply region into which material may be fed, the trough also having a delivery aperture at least part of which is positioned in a portion of the trough remote from said supply region, through which material may be spread, the spreader further comprising distributing means for distributing material which has been fed into the trough in said supply region, in a direction along the length of the trough so that the material may be spread from that part of the aperture which is remote from said supply region.

A simple but effective form of distributing means comprises a shaft having a screw profile, which shaft extends, along the bottom region of the trough.

Preferably, the cross section of the trough is narrow in the bottom region with respect to its upper region, so that material supplied to the trough is automatically directed to the distributing means by the sides of the trough. For instance, the trough may have a substantially V-shaped cross section.

Preferably the trough is mobile and can be driven in a direction perpendicular to its length. It is then possible to spread material from the trough in a strip whose width is determined by the dimensions of the delivery aperture. The depth of such a strip of material will be at least partly controlled by the combination of the speed at which the trough is driven, and the wideness of the delivery aperture in the direction of travel of the trough. Preferably both factors are adjustable so that the depth of a strip of spread material may be selected.

The trough may be mounted on a framework which runs for instance on wheels. The framework may be provided with a motor to drive the wheels to achieve movement of the trough. Conveniently, the trough may be driven in directions in addition to a direction perpendicular to its length, the configuration of the wheels in relation to the framework being adjustable.

In order to achieve a finish which is at least substantially level to a strip of delivered material, it is preferable that the trough should also be provided with a level sensor or sensors and means for controlling its position relative to the wheels so that unevenness in the ground where the wheels are travelling is not reflected in the surface of the strip of spread material.

Preferably the trough is constructed in sections so that its length may be varied for use under different local constraints. Preferably the length of the delivery aperture along the trough may also or alternatively be varied so that different widths of strip may be spread. In this respect, it may be preferred that the delivery aperture can be blocked off in intermittent sections so that two or more parallel strips of material may be delivered simultaneously.

A material spreader according to specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a front elevation of the material spreader;

Figure 2 shows a plan view of the material spreader;

Figure 3 shows an end elevation of the material spreader; Figure 4 shows a front elevation of a trough for use in the material spreader;

Figure 5 shows a cross section of the trough of

Figure 4;

Figures 6a and 6b show plan views of the spreader in use;

Figure 7 shows an end elevation of the spreader in use;

Figure 8 shows a front elevation of a modified trough for use in the spreader;

Figure 9 shows a cross section of the spreader in use with the addition of a vibrating screeder; and

Figures 10a and 10b show a modification which may be made to the spreader to increase its versatility.

It should be noted that all of the Figures are schematic rather than accurately detailed representations.

Referring to Figure 1, the material spreader 1 comprises a trough 2 supported by a framework. The framework has two end parts 3 provided with wheels 4 and carries the trough 2 by means of a pair of support shafts 5 which extend the length of the trough 2, being themselves supported at each end part 3.

Referring to Figures 1 and 2, inside and along the bottom of the trough 2 there extends a feed shaft 6 with a screw profile. The feed shaft 6 runs the entire length of the trough 2 and can be driven to rotate by a motor 7 mounted on an end part 3 of the framework. The feed shaft 6 comprises a central cylindrical shaft having a helical thread 29 thereon. The central cylindrical shaft has a diameter of the order of 80 mm while the helical thread 29 has an outer diameter across the drive shaft 6 of the order of 300 mm. The thread 29 is also curved somewhat towards the drive direction of the drive shaft 6 in use in feeding material along the trough 2.

Referring to Figures 3 and 5, the trough 2 has a predominantly V-shaped profile so that it presents a wide mouth at the top and narrows towards the bottom. The bottom of the trough 2 is open providing a delivery aperture 8 whose width in a direction perpendicular to the length of the trough 2 is set by means of shutters 9. One of the shutters 9 is hinged so that the width of the aperture 8 is adjustable.

In order to set the aperture 8 at different widths, the hinged shutter 9 may simply be secured by the use of bolts of different lengths to the non-hinged shutter 9 or with respect to the framework.

Referring to Figure 6a, in operation in its simplest form, the trough 2 is mounted in the framework so that it extends across an area 10 on which material is to be spread and the delivery aperture 8 (not shown on Figure 6a) extends the length of the trough 2. Material is fed into the trough 2 at an end 11 thereof. The feed shaft 6 is rotated so that the material is fed along the length of the trough 2, and the trough 2 is driven along the area 10 in the direction indicated on the Figure by the arrow, the material being spread over the area 10 from the delivery aperture 8. The material is thus spread in an even layer over the area 10 intended.

Preferably, the feed shaft 6 is rotated continuously while material is spread, and material is fed into the trough 2 continuously through the spreading operation.

Clearly the depth of material so delivered to the area 10 is controlled in the first instance by the speed at which the trough 2 is driven along the area 10 and by the width of the aperture 8 as set by the shutters 9. However, if for instance the wheels 4 are driven over uneven ground at the sides of the area 10, then the system may be disturbed and the material may be spread unevenly. In order to avoid this, referring to Figures 2 and 3, the end parts 3 of the framework are designed so that the level of the wheels 4 may vary with reference to the rest of the framework. The wheels 4 support the rest of the framework by means of hydraulic supports 12 and tilt sensors 13 are provided on each end part 3 of the framework to detect tilting of the trough, which may be due to unevenness of the ground under the respective wheels 4. Information from the tilt sensors 13 may then be used to adjust automatically the level of the individual wheels 4 with respect to the framework, and so maintain even delivery of material from the trough 2.

Suitable sensors and adjustment mechanisms suitable for use in such arrangements are known and are not therefore described in detail herein. However, the tilt sensors 13 may for example be of a type in which a servomechanism acts to keep contact fingers mounted at either end of the trough 2 in contact with respective string lines. Alternatively, a single component tilt sensor 13 may be used, mounted on the trough or framework, comprising a gyroscopic device, or an electrical device in which a plumbline or weight activates a servomechanism by swinging into contact with a fixedly mounted contact element.

Referring to Figure 7, the feature of level adjustment of the wheels 4 may also be useful where large areas of material are to be laid. For instance, where an area of concrete which is wider than the length of the trough 2 is to be laid, the concrete will be laid in strips. This is straightforward where the first strip 14 is concerned but where a second strip is to be laid alongside the first, the wheels 4 at one end of the trough 2 will necessarily be raised relative to those at the other end by the depth of concrete in the first strip 14, or by the depth of a framework holding said concrete in place. By adjusting the level of the wheels 4 at each end of the trough 2 independently, it is possible to compensate for the difference in wheel level and to avoid tilting of the trough 2 along its length.

Referring to Figures 1 and 4, in a modified version the trough 2 is of adjustable width so that it can be used to lay strips of material of different widths. To achieve this flexibility, the trough 2 is made in multiple panels 15 which can then be added or removed to achieve a specified length of the trough 2. The panels 15 are connected to neighbouring panels by means of dovetail joints so that it is a relatively simple matter to add or remove them by sliding them in and out from the top of the trough. However being dovetail joints, the panels 15 will be held together firmly once in place and will not tend to separate. The shutters 9 are also constructed in a plurality of panels in the same manner.

The panels of the trough 2 and shutters 9 may each for instance be 1 metre wide, so that the length of the spreader 1 as a whole can be varied in units of 1 metre.

In order to accommodate the adjustable width of the trough 2, the support shafts 5 are similarly constructed in removable sections, jointed by means of dove tail joints, each secured by a heavy duty bolt 16. Lastly, the feed shaft 6 is also constructed in removable sections. These sections are jointed by means of pin and socket joints, each joint being secured by a heavy duty screw 17, transverse to the drive shaft 6. The head of each heavy duty screw 17 is countersunk into the drive shaft 6, and neither end protrudes from the shaft 6. This is to prevent damage to the screws 17 or shaft 6 during use of the spreader 1.

A particular advantage of using shutters 9 constructed out of individually adjustable panels arises where selected ones of the panels can be closed off so as to divide up the delivery aperture 8 of the trough 2 into a plurality of apertures spaced apart. Referring to Figure 6b, this is useful where plural strips of material 18 are to be laid with gaps 19 in between. Such an arrangement may be required for instance where concrete paths are to be laid, separated by strips of grass. A spaced pair of paths may be created simultaneously, an intervening grass strip being created later in the gap 19.

It may also be useful to close part of the length of the delivery aperture 8 where there is wet or boggy ground adjacent an area where material such as concrete or crushed rock is to be spread. Referring again to Figure 6b, it may be difficult to deliver material directly to where a strip 18 is to be laid because it would be necessary to access it over land 20 too wet to take the weight of a delivery vehicle. Using a trough 2 in which the delivery aperture 8 is closed off over the wet land 20, material can be transported across the wet land 20 from an acceptable delivery point to where the strip of material 18 is to be laid.

The trough 2 may be further modified for particular applications. For instance, it may be preferred that the profile of the trough 2 along its bottom should not be straight. By inserting non-rectangular panels 21, a different profile can be achieved. This can have the effect of varying the depth of material in the trough 2, along its length. Because more material will tend to be delivered from the trough 2 where the depth is greater, it is then possible to create a non-level but controlled profile of material being spread. It may be found preferable that during spreading of a material from a trough 2, one or more operators should be able to manoeuvre material within the trough 2, for instance to improve or modify the even distribution of material along it. Referring to Figure 2, a platform 22 may be provided which runs along one side of the trough 2, and on which an operator or several operators may stand during use of the material spreader.

A safety feature which may be incorporated into the platform 22 is one or more weight-sensitive strips 28 which act to stop the drive shaft 6 as soon as weight is removed. This would provide an automatic emergency stop in the event that an operator fell from the platform 22 into or towards the trough 2. It could further be used by an operator if any other undesirable object entered the trough 2, for instance a solid block of concrete being delivered in error from a delivery truck amongst a premixed load of concrete. Such blocks are known to occur, for instance when a residue of concrete is allowed to set inside a truck, and could otherwise cause damage to the feed shaft 6 and/or the trough 2 itself.

Previously it has been necessary in some instances to produce an accurately level surface of a material which has been spread, by the use of a vibrating screeder. The screeder itself may be automated to the extent that the operators merely have to steer it but the levelling operation tends to be boring for the operators as well as generating an extra and separate task in the spreading of the material. Also the operators necessarily have to walk on the unscreeded material. As mentioned above, in the case of reinforced concrete this can cause problems in disturbing the wires or other reinforcement. With a material spreader according to an embodiment of the present invention, it is possible to attach a vibrating screeder so that it is both pulled along and directed by the spreader. It is not then necessary that it should be separately operated.

Referring to Figure 9, a simple arrangement for attaching a vibrating screeder 23 is that it should be coupled to one of the support shafts 5 supporting the trough 2, or to the trough 2 itself. It will then be towed behind the trough 2, acting on the material 24 being delivered therefrom.

The material spreader itself may be steered along a surface either by direct mechanical means, such as by being drawn along by winches, or by the use of a sensor or sensors combined with a servomechanism to direct the spreader with reference to a target. Devices of this type are known and are not therefore further described herein.

The rate at which material is fed from the trough 2 is affected by a number of factors, including (as mentioned earlier) the depth of material in the trough. Referring to Figure 5, the trough 2 may be filled to different depths 25 in accordance with the constraints of a particular spreading task. In order to control the effect of the different depths, the width of the delivery aperture 8 may be varied by adjustment of the shutters 9.

Another factor in determining the rate at which material is delivered from the trough 2 is the design and speed of rotation of the drive shaft 6 since the screw profile of the shaft 6 can have the effect of feeding material downwards into the delivery aperture '8 as well as along the trough 2. Hence the speed of rotation of the shaft 6 will in part determine the depth of material spread. The shaft 6 may be driven by a motor 7 mounted on an end part 3 of the framework and the speed of rotation may then be varied by adjusting the drive from the motor 7 or the speed of the motor itself. Suitable speeds of rotation will be determined in use of the spreader 1 but it should be noted that increased speed of rotation will not necessarily linearly increase the rate at which material is delivered. This is because the effect of the drive shaft 6 on the material may change as the material has less time to settle into the screw profile of the shaft 6.

Referring to Figure 10, a further modification which can add versatility to a material spreader 1 according to the present invention is a pumped extension hose 30. This is particularly useful where material is to be delivered to areas that the construction of the spreader 1 does not lend itself to accessing. For instance, it may be necessary to spread concrete close up to a structure, but the end parts 3 of the framework, the hydraulic supports 12 and the wheels 4 do not allow the trough 2 to be brought close enough to that structure. The total length of the spreader 1 may for example be of the order of 7.2 m, the end parts 3, supports 12 and wheels 4 adding 60 cm to each end of a 6 metre trough 2. This means that at least a 60 cm strip must be left unspread between a structure and the edge of the concrete delivered from the trough 2.

Referring to Figure 10a, it is possible to replace a 1 metre section of the trough 2 with a modified section which pumps material from the trough 2 into a flexible hose 30 which can then be directed at will, within the limitations of the length and flexibility of the hose 30.

The modified section has no delivery aperture but instead has a lateral extension 31 to which the hose 30 can be coupled, and a piston 32 driven by virtue of being mounted at one end, eccentrically on a rotating plate 33. The piston 32 has a guide slot 34 which accommodates a pin 35, the pin 35 being mounted on the side of the modified section and controlling the movement of the piston 32 so that rotation of the plate 33 causes the piston 32- to reciprocate at the opening of the hose 30. Material driven along the trough 2 will enter the modified section. In use, the piston 32 will then pump material into the hose 30.

The arrangement is such that the rotating plate 33 is mounted above the level of material in the modified section, in use, while the opening to the hose 30 lies below that level. This reduces the effect of wear by contact of material with the plate 33 .

The plate 33 is driven by a motor 36 mounted on the side of the modified section. Alternatively, however, it could be driven by means of an extended drive shaft and a motor mounted on an end part 3 of the framework, the modified section being mounted at a different point along the trough 2. That is, although the modified section is shown mounted at an end of the trough 2, it may alternatively replace a central section of the trough 2, or effectively constitute a short trough itself, there being no further sections.

The use of a lateral extension 31 is not necessary, it being possible to couple the hose 30 directly to a hole in a modified panel of the trough 2. However, with the extension 31 it is possible to load material for pumping through the hose 30 without the danger of damage to the rotaring plate 33 or other parts of the drive to the piston 32.

Claims

CLAIMS :

1. A material spreader comprising an elongate trough having a material supply region into which material may be fed, the trough also having a delivery aperture at least part of which is positioned in a portion of the trough remote from said supply region, through which material may be spread, the spreader further comprising distributing means for distributing material which has been fed into the trough in said supply region, in a direction along the length of the trough so that the material may be spread from that part of the aperture which is remote from said supply region.

2. A material spreader according to claim 1 wherein said distributing means comprises a shaft having a screw profile, which shaft extends along the bottom region of the trough.

3. A material spreader according to claims 1 or 2 wherein the cross section of the trough is narrow in the bottom region with respect to its upper region.

4. A material spreader according to any one of the preceding claims wherein the trough is mobi-le and can be driven in a direction perpendicular to its length.

5. A material spreader according to claim 4 wherein the trough is mounted on a framework, the framework being provided with wheels.

6. A material spreader according to claim 5 wherein the framework is further provided with a motor to drive the wheels so as to achieve movement of the trough.

7. A material spreader according to claim 5 wherein the configuration of the wheels in relation to the framework is adjustable.

8. A material spreader according to claims 5 or 6 wherein the trough is provided with level sensing means and means for controlling its position relative to the wheels in a vertical direction.

9. A material spreader according to any preceding claim wherein the trough is constructed in sections so that its length may be varied.

10. A material spreader according to any preceding claim wherein the length of the delivery aperture along the trough may be varied.

11. A material spreader according to any preceding claim wherein the delivery aperture in a direction along the trough may be blocked off intermittently so as to form a plurality of delivery apertures therefrom.

12. A concrete spreader comprising a material spreader according to any one of the preceding claims.

13. An extension arrangement for use in a material spreader according to any one of the preceding claims, comprising a container which can be mounted to form the elongate trough or a section of the elongate trough, the container having means for mounting an external, flexible hose thereon so that the hose communicates with the interior of the container, and pumping means to pump material from the container into the hose, in use.

14. A material spreader substantially as described hereinbefore with reference to the accompanying drawings.