GB2030433A - Spreader - Google Patents

Abstract

A spreader for distributing granular or finely-divided material has a hopper 10 mounted on ground wheels 12, 12'. The wheels reciprocally drive an apertured belt 14 which conveys material horizontally from hopper outlets to apertures 13a in a material support plate 13, through which the material can fall to the ground. Since the plate 13 is screened from the direct gravitational flow of material from the hopper, the spreader distributes material only when the ground wheels are rotating. By adjustment of the belt drive mechanism, the stroke of the reciprocatory movement of the belt can be varied to vary the rate of distribution of material relative to the rotational speed of the ground wheels. A material stirrer 25 within the hopper 10 is also driven by the ground-wheels 12, 12'. <IMAGE>

Description

SPECIFICATION Improvements in and relating to spreaders for granular or finely-divided material This invention relates to a spreader for distributing material in granular or finely-divided form, and in particular to a spreader mounted on ground-wheels for movement over roads or paths to spread salt, grit or sand, or movable over agricultural land to spread material such as fertilizer, phosphate or slag.

The present invention seeks to provide a spreader of simple and relatively inexpensive construction with a relatively small number of moving parts and which can be manufactured in corrosion resistant materials.

According to the present invention there is provided a spreader for distributing material in granular or finely-divided form, the spreader comprising a hopper supported on ground-wheels, apertured material support means extending transversely of the outlet of the hopper and apertured metering means extending across the upper face of the support means and movable with respect to said support plate to move material within the hopper in apertures of the support means, and flow blocking means operative to prevent the direct gravitational flow of material from said hopper into said apertures when the metering means is stationary.

Preferably, the metering means is located above and rests on the material support means, the latter being in the form of an apertured support plate, and said blocking means define chutes which direct material on to the metering means. The chutes are located above the solid portions of the support plate, and the blocking means are located above the apertures of the support plate.

Preferably, the metering means is a flexible apertured web. This can be an endless chain or belt, the upper run of the chain being in contact with the support plate, the chain passing around parallel spaced rollers at least one of which is formed by or includes a sprocket forming part of the drive means.

The drive means is preferably driven by rotation of the ground-wheels. Conveniently the drive means comprises a rotor mounted on an axis extending along the direction of movement of the spreader and driven through gearing from one of the ground wheels, a crank arm being connected at one end to the rotor, and a link arm extending radially from the sprocket, the outer ends of the crank arm and the link arm having an interconnection which is movable radially of the sprocket to vary the angle of reciprocatory movement of the sprocket for each rotation of the rotor and hence vary the displacement of the metering means and thus the quantity of material metered at each reciprocatory movement.

The lower run of the belt can be located below the upper run to assist in breaking up the material falling on the lower run.

One embodiment of a spreader in accordance with the invention will now be particularly described with reference to the accompanying drawings in which: Figure l is a vertical section through the spreader in a plane perpendicular to the direction of its movement; Figure 2 is a plan view of the spreader of Figure 1; Figure 3 is a side elevation part sectioned of the spreader of Figures 1 and 2; Figure 4 is a diagrammatic representation of the operation of the spreader.

As seen in the drawings, the spreader comprises a hopper 10 having opposite end supports 11 in which ground-wheels 12, 12' are mounted for rotation.

The hopper is formed with sides which are inclined inwardly and downwardly, and nearthe bottom of the hopper are a number (for example four) of roof shaped blocking members 15 which co-operate with the sides of the hopper to define a series of spaced-apart rectangular hopper-outlet apertures 10a. Spaced below the outlet apertures 10a is a material support plate 13 which obstructs the direct downward gravitational flow of material through the apertures 10a. The material support plate 13 is however formed with apertures 13a which are disposed beneath the blocking members 15 (see Figure 2).

An apertured metering member 14 rests on the support plate for reciprocatory movement longitudinally of the plate to move the apertures 14a of the metering member across the apertures 13a of the support plate. It will thus be seen that the blocking members 15, the metering member 14 and the support plate 13 form in effect a valve which controls the flow of materials out of the outlet of the hopper.

This is achieved in that material is free to pass through the outlet apertures 1 Oa of the hopper into the apertures of the metering member 14 but are thereafter blocked by the solid portions of the support plate 13. Where the support plate is formed with apertures 13a, the flow of material directly from the hopper is blocked by the blocking members 15.

Accordingly, the material entering the apertures of the support plate can only do so by the lateral movement of the metering member 14 and the amount of material moved into the apertures of the support plate by the metering member will depend directly on the speed and stroke of the reciprocatory movement of the metering member.

The metering member 14 preferably takes the form of a chain or apertured belt, made of stainless steel links 14which passes around rollers 16, 16' or the like journalled in the end support 11 of the hopper 10 adjacent opposite ends of the series of outlet apertures 1 Oa of the hopper. The roller 16 is formed as a drive sprocket for connection to a drive device by means of which the chain can be reciprocated.

The upper run of the chain 14 is supported on the support plate 13 while the lower run of the chain is arranged directly below the upper run and assists in breaking up material discharged through the metering device from the hopper.

The drive device for the metering member (as seen best in Figure 4) conveniently comprises a rotor 17 mounted for rotation on an axis Ywhich lies along the direction of movement of the spreader, the rotor 17 being driven from the ground-wheels through right-angle drive gearing 18. A crank arm 20 connected at one end to the rotor 17 is connected at rotor 17 being driven from the ground-wheels through right-angle drive gearing 18. A crank arm 20 connected at one end to the rotor 17 is connected at its opposite end to a link arm 21 which is connected by a coupling 22 to the drive sprocket 16.The interconnection between the adjacent end of the crankarm 20 and the linkarm 21 isa movable connection formed, as shown in Figure 1, by a pin 23 on the arm 20 engaging in any selected one of a number of apertures 24 of the link arm 21, so that the effective length of the link arm can be varied and hence the stroke of the reciprocatory movement of the link arm 21 by the rotor 17 can be varied. This variation of the stroke of the link arm will naturally vary the stroke of the metering member 14 and hence the rate at which material is dispensed through the metering device.

In order to prevent bridging of material in the hopper, an agitator or stirrer 25 formed by a shaft extending horizontally through the hopper and supporting radial fingers 25', is rotated by a drive chain 26, driven by road wheel 12'.

Since the drive for the metering member 14 is taken from the ground-wheels 12, 12', the faster the spreader is moved over the ground, the faster will be reciprocatory movement of the member 14 and hence there will be a substantially constant relatonship between the rate at which the material is dispensed and the speed at which the spreader is driven. As a result the amount of material spread per unit area of ground covered will remain constant for each value of the effective length of the link arm 21.

Variation of the effective length of the link arm 21 will vary the volume of material spread over unit area of ground.

The metering member 14 is, as indicated above, preferably made of stainless steel to resist corrosion and with the same aim, the hopper 10, the blocking members 15 and the material support plate 13, can conveniently be made of plastics, stainless steel, or other corrosion resistant material.

Although the embodiment of the invention described above utilizes metering means which performs a reciprocatory movement, the spreader coulc alternatively employ metering means which moves in a single direction. In this event the quantity of material distributed could be controlled by varying the size of the apertures in the support plate.

Claims (9)

1. a spreader for distributing material in granular orfinely-divided form, comprising a hopper supported on ground-wheels, apertured material support means extending transversely of the outlet of the hopper and apertured metering means extending across the upper face of the support means and movable with respect to said support plate to move material within the hopper into apertures of the support means, and flow blocking means operative to prevent the direct gravitational flow of material from said hopper into said apertures when the metering means is stationary.

2. A spreader according to claim 1 wherein said metering means comprises an apertured belt, web or chain.

3. A spreader according to claim 1 or claim 2 wherein the flow blocking means constrain the flow of material from the hopper to one or more locations traversed by the metering means, the apertures of the material support means being spaced from the, or each, location and covered by said flow blocking means.

4 A spreader according to any preceding claim having a transmission connecting the ground wheels to the metering means and operative to convert rotary movement of the ground wheels into reciprocatory movement of the metering means.

5. A spreader according to claim 4 wherein said transmission contains a reciprocally movable arm connected to the metering means and connected, at a point thereon spaced from its axis, to a reciprocally movable member driven by the ground-wheels, the distance between said point and said axis being variable to vary the stroke of the metering means.

6. A spreader according to any preceding claim including a stirrer disposed within the hopper above the metering means and rotatable by a drive connection from the ground wheels.

7. A spreader according to any preceding claim wherein the metering means comprises an endless member having an upper run which cooperates with said material support means and a lower run disposed beneath the material support means in the path of material falling from the apertures of said material support means.

8. A spreader according to any preceding claim wherein said metering means comprises a series of interconnected stainless steel links.

9. A spreader substantially as herein described with reference to the accompanying drawings.