GB2197599A - Improvements in crushers - Google Patents

Abstract

The discharge conveyor 6 of a crushing plant suitable for reinforced concrete has an end section 6A which is movable downwards or removable in order for obstructions caused by metal reinforcement to clear into pit P. Alternatively, conveyor 6 may be slidable lengthwise in the direction D. A mini-excavator 8 is provided to assist flow of material into the crusher 3. <IMAGE>

Description

IMPROVEMENTS IN CRUSHERS Jaw crushers have been used for many years to reduce freshly quarried rock. More recently, crushers have been used on demolition sites, and reclaimed concrete has become an important source of aggregate. Several problems arise when crushers are used on demolition sites. In particular, metal reinforcement may jam the discharge conveyor and even damage the belt, leading to considerable down-times while repairs are carried out.

Also, concrete does not feed easily between the jaws and may need to be assisted.

The modified crusher proposed herein overcomes these problems.

The drawing is a partially broken away side elevation of a Parker 'Rock Ranger' crushing plant modified as will be described below.

Referring to the drawing, the plant includes a frame 1 on which is supported a vibratory unit 2 for feeding recovered concrete to a single toggle jaw crusher 3 driven from an engine 4. Fines are removed by a screen 5 before reaching the crusher. The crushed product is discharged onto a belt conveyor 6 and conveyed to a waiting truck.

A lower end section 6A of the conveyor with a length of about one metre is articulated to the main part of the conveyor by means of a removable shaft 7 to enable this section to be swung into a position shown in broken lines within a pit P excavated beneath the plant. The end section is normally secured to the main part of the conveyor by bolts or pins which can be knocked or burned out to release the section 6A.

Mounted on an extension 1A of the frame 1 is a miniexcavator 8, the main boom 9 of which has a pivot located at about one metre above the axis of the flywheel 10 of the operating mechanism.

In operation, recovered concrete, which may incorporate metal reinforcement, is tipped into the vibratory unit 2 which feeds it across the screen 5 to the crusher 3. The excavator 8 is used to assist the material across the screen and into the crusher and to clear obstructions as they arise.

In the event that metal reinforcement blocks the conveyor, the bolts or pins joining end section 6A to the main part of the conveyor are removed and the end section swung down to enable the obstruction to be cleared. If necessary, the shaft 7 is knocked out and the end section of the conveyor frame removed. Following clearing of the obstruction, the end section is returned to its upper position by means of a chain lowered through the crusher, or by a fork lift truck for example.

In an alternative construction, the conveyor is mounted in the lower framework 11 so as to be slidable lengthwise in the direction D in order to clear any blockage.

The section 6A may be swung down or the conveyor displaced lengthwise to allow heavily steel impregnated concrete to be crushed directly into the pit P, from which it is removed by an excavator.

Claims (3)

1. A crushing plant for recovered concrete wherein an end section of the discharge conveyor is articulated to the main part of the conveyor, whereby the end section may swing down to clear obstructions.

2. A crushing plant including mechanism for promoting flow of material to be crushed between the jaws of the crusher.

3. A crushing plant for recovered concrete wherein the discharge conveyor is movable lengthwise to clear obstructions at the upstream end of the conveyor.