GB2171930A - Spreader apparatus for use with screens - Google Patents

Abstract

A spreader apparatus for feeding material to be screened to a screen box comprises a spreader plate which is movably mounted above the screen box on a support framework and is continuously reciprocated relative thereto to deflect material impinging upon its surface on to the deck or the upper of the decks of the screen box in a substantially rectangular pattern thereon.

Description

SPECIFICATION Spreader apparatus for use with screens This invention relates to a spreader apparatus for use with a screen box which is mounted at the discharge end of another apparatus for processing material and is to receive material discharged thereonto. The screen box is downwardly inclined and has at least one reticular or non-reticular wire deck to size classify material fed thereonto as it passes theredown. The spreader apparatus is for use in deflecting material to be discharged onto the upper end of the deck or of the upper of the decks of the screen box.

Heretofore, where the other apparatus was an inclined endless belt conveyor, a problem has existed in that material fed up the inclined conveyor, due to the transverse concavity of the upper run of the endless belt thereof, is dicharged on to the upper end of the wires centrally of the deck or the upper of the decks in a substantially elliptical impact pattern thereon. Due to constant discharge of material on to the deck the parts of the wires at the elliptical impact area wear through while the remainder of these wires and the other wires-are still in good condition.To mitigate this problem, a plate has been rigidly mounted beyond the discharge end of the conveyor so that it is interposed in the path of any material discharged thereat, the plate being angled such that when material impinges upon its surface it spreads the material to deflect it onto the wires forming an elongate pattern thereacross. The use of this plate has increased the areal dimensions of the impact area of the deck and has therefore increased the life of the deck, but not significantly.

An object of the present invention is to increase further the areal dimensions of the impact area to mitigate the above problem and prolong the wear life of the wires of the deck.

According to the present invention, a spreader apparatus for a screen box comprises a spreader plate mounted above the screen box on a support framework, and being movable relative thereto to deflect material impinging upon its surface on to the deck or the upper of the decks of the screen box in a substantially rectangular pattern thereon, and means to continuously reciprocate said plate with discharge of material onto said screen box.

Preferably, the plate is pivoted to said support frame-work whereby the plate can be attitudinally altered for deflection of material.

Preferably, also, the means is a motor whose output is arranged to reciprocate the plate.

Alternatively, the means links the plate with a driven part of the other processing apparatus, such as the upper roller of a conveyor in which the means comprises a link pivoted to the plate and to an arm projecting from a shaft of said roller.

The foregoing and further features of the invention may be more readily understood from the following description of some preferred embodiments thereof, by way of example, with reference to the accompanying drawings, in which: Figures 1 and 2 are schematic side elevational views of one embodiment of the invention; and Figure 3 is a schematic side elevational view of an alternative embodiment.

Referring firstly to Figures 1 and 2 of the drawings a spreader apparatus for a screen box 10 comprises a spreader plate 11 pivotally mounted above the screen box 10 on a support framework 12 extending from and beyond the discharge end of a conveyor 13. Means are provided to continuously reciprocate said plate 11 with discharge of material onto said screen box 10 which conveniently in this embodiment is with movement of said conveyor 13. This reciprocatory movement is in a manner involving variation in the attitude of the plate 11 relative to the deck 14 of the screen box 10. The means links the plate 11 with the upper roller 15 of the conveyor 13 and comprises a link 16 pivoted to the plate 11 above the plate's pivotal mounting on the support framework 12 and to the upper end of an arm 17 radiating from a shaft 18 of the roller 15.

In use, material fed up the conveyor 13 is discharged at its upper end and impinges on the surface of the plate 11 during its reciprocating travel and is deflected therefrom onto the deck 14 of the screen box 10 in a substantially rectangular impact pattern. Depending on the initial attit-udinal position of the plate 11 and the amount of reciprocatory travel, the higher and lower extents of the impact area transverse of the screen 10 will be determined.

Modifications (Figure 3) of the above-described spreader apparatus may include the link 14 being length-adjustable by means 19, a row of pivotal mountings 20 being provided on.the support framework for the plate 11 to be mounted, a row of pivotal mountings 21 being provided on the plate to which the link 14 may be connected, and the arm being a torque arm gear box 22 mounted on the shaft 18 and having an output drive disc 23 with a row of radial mountings 24 to any one of which the link 14 may be pivotally connected. The torque arm gear box 22 can be rotatably adjusted for the drive disc 23 thereon to be moved towards or away from the plate mounting thereby to enable the initial attitudinal position of the plate 11 to be adjusted.

In a further modification (not shown) the spreader plate may have laterally extending lugs tracking laterally inclined slides provided on the support framework, the plate reciprocating slidably in its tracks on movement of the link.

The material may be discharged onto the screen box from a chute and for this embodiment, the means may be a motor whose output through an eccentric drive cam is arranged to reciprocate the plate.

The deck may be of greater length than the length of the screen box and be for mounting in the screen box for sliding movement relative thereto whereby material is fed on to the deck when the deck has its extended length projecting beyond the bottom of the screen box. When the impact area is partially worn the deck is slid up the box for the worn impact area of the deck to underlie the conveyor and the material discharged is deflected on to the deck to form an impact area below said worn impact area thereby to further extend the life of the deck. Aiternatively, the deck is of the correct size for the screen box but can be longitudinally reversible therein so that when the impact area is partially worn the deck is reversed.

In a further modified embodiment, (not shown) one or more further spreader plates may be provided, arranged substantially co-planar with the spreader plate 11 and spaced therefrom. Such further spreader plate(s) is/are mounted and linked for reciprocal movement with the one spreader plate 11 to provide an increased impact area of the screen box deck.

It has been found that the above described spreader apparatus increases the screening efficiency of the screen box since it allows a greater throughput of material than hereto-fore.

Claims (6)

1. A spreader apparatus for a screen box com- prising a spreader plate mounted above the screen box on a support framework, and being movable relative thereto to deflect material impinging upon its surface on to the deck or the upper of the decks of the screen box in a substantially rectangular pattern thereon, and means to continuously reciprocate said plate with discharge of material onto said screen box.

2. An apparatus as claimed in claim 1 wherein the plate is pivoted to said support framework whereby the plate can be attitudinally altered for deflection of material.

3. An apparatus as claimed in claim 1 or 2, wherein the means is a motor whose output is arranged to recriprocate the plate.

4. An apparatus as claimed in claim 1 or 2, wherein the means links the plate with a driven part of the other processing apparatus, such as the upper roller of a conveyor, in which the means comprises a link pivoted to the plate and to an arm projecting from a shaft of said roller.

5. An apparatus as claimed in any preceding claim wherein one or more further spreader plates are located substantially coplanar with and spaced from said spreader plate, said further spreader plate(s) being linked to move with movement of said spreader plate.

6. A spreader apparatus for a screen box substantially as hereinbefore described with reference to the accompanying-drawings.