GB2239409A

GB2239409A - Jaw crusher

Info

Publication number: GB2239409A
Application number: GB8922780A
Authority: GB
Inventors: Roy Heawood
Original assignee: BROWN ENGINEERING Ltd
Current assignee: BROWN ENGINEERING Ltd
Priority date: 1989-10-10
Filing date: 1989-10-10
Publication date: 1991-07-03
Also published as: GB8922780D0; GB9021818D0

Abstract

A jaw crusher 10 comprising a pair of converging jaws 12, 14, a hydraulic cylinder 30 and piston 28 arrangement to move jaws 14 when a non-crushable object is encountered. The jaw crusher 10 is typically used for crushing stone and brickwork and should non-crushable material such as iron or steel accidently enter into the crusher 10 a pressure sensing device eg pressure sensitive valves in roar pan 30a detects the presence of non-crushable material and releases the jaw 14 so as to allow the non-crushable material to pass therethrough or be removed. <IMAGE>

Description

JAW CRUSHER The present application relates to a jaw crusher, typically a jaw crusher for crushing stone and brickwork etc.

Previously proposed jaw crushers comprise a pair of converging jaws, one of which is driven in a reciprocating manner towards the other so as to perform a grinding or crushing action on any material between the jaws. However, problems can arise when a non-crushable material such as iron or steel is accidentally introduced into the crusher and could cause permanent damage to the machine.

It is an object of the present invention to obviate or mitigate this problem.

In accordance with the present invention there is provided a jaw crusher comprising a pair of converging jaws, a first, reciprocating jaw being provided with means for a reciprocal driving movement towards a second, non-reciprocating jaw, said second jaw being provided with a hydraulic cylinder and piston arrangement for moving said second jaw away from said first jaw when a non-crushable object is encountered.

It is normal for the jaws to converge towards their lower ends such that material naturally falls down during crushing. In such an arrangement it is preferred that the second jaw is pivotted at its upper end such that the lower end can be swung away from the first jaw by the hydraulic arrangement.

It is also preferred that an automatic pressure sensing device, typically mounted in the hydraulic cylinder, is provided such that the presence of a non-crushable material can be detected. The pressure sensing device can also be used to actuate the hydraulic arrangement to move the second jaw.

In one preferred embodiment, the hydraulic arrangement is such that when a non-crushable object is detected, hydraulic fluid is vented from one part of the cylinder while fluid is pumped under pressure to another part of the cylinder so as to positively move the piston and withdraw the second jaw.

In a second preferred embodiment, the arrangement is such that the presence of the non-crushable object causes fluid to be tranferred from one end of the cylinder to the other due to the reciprocating action of the first jaw being transmitted via the object to the second jaw, any surplus fluid expelled from the cylinder being drained away. In this case, movement of the second jaw is essentially passive.

In either case, it is preferred that actuation of the hydraulic arrangement causes the driving means to be disengaged.

The present invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 and 2 show section side views of alternative embodiments of the present invention.

In Figs. 1 and 2 the portion of the drawing relating to the first jaw (to the right of line AA) is the same in both cases and identical reference numerals will be used for this part in both figures.

Referring now to the drawings, the crushers shown therein comprise a body 10 (shown in part) having a pair of opposed jaws 12, 14 mounted therein so as to converge towards their lower ends. The first jaw 12 is connected to a drive motor (not shown) at its upper end via suitable transmission means such that the first jaw 12 can be caused to oscillate towards the second jaw 14. Toward the lower end of the jaw 12, there is provided a mounting point 16 in which is located one end of a toggle plate 18, the other end of which is connected to a mounting. This provides a reaction to the movement of the jaw 12 and assists in the crushing action. In this respect both embodiments shown in the drawings correspond to existing jaw crusher designs.

Referring now to Fig. 1, the second jaw 14 is pivotally mounted at its upper end 20 so as to be movable in an arc through a vertical plane. The lower end of the jaw 14 is provided with a mounting block 22 having a cup-shaped recess 24 therein. The recess 24 serves to locate the rounded end of push rod 26 which is pivotally connected to a piston 28 in a hydraulic cylinder 30. In the drawings only one cylinder is shown but it will be appreciated that any appropriate number can be used. The cylinder 30 is pivotally mounted on the body 10 and serves to provide a reaction base when fully extended as shown in the drawing.

A smaller cylinder and piston arrangement 32 is provided to pull the jaw 14 against the piston so as to take up any slack in the system.

In use, the rear part 30a of the cylinder 30 is pressurized so as to urge the piston 28 to the front part 30b thereof.

The motor is operated and material to be crushed is fed to the upper part of the crusher between the jaws 12,14. When a non-crushable object is encountered and the reciprocating action of the jaw 12 causes excessive pressure to be applied to the second jaw 14 and hence via the rod 26 and piston 28 to the cylinder 30. When this pressure exceeds a predetermined level, one or more pressure activated valves (not shown) at the rear part 30a of the cylinder open so as to discharge fluid therefrom and at the same time fluid is pumped to the front part 30b of the cylinder so as to cause the piston 28 to be withdrawn fully into the cylinder 30, the arrangement 32 causing the second jaw to be withdrawn and the non-crushable object to be passed or removed from the crusher. At the same time, the motor drive is terminated.To recommence operation, the piston is moved to its forward position, the valves reset and the motor restarted.

Referring now to Fig. 2, the crusher shown therein differed from that previously described with regard to the mounting and operation of the hydraulic cylinder. In this case a pivot mounting 40 is provided on the jaw 14 to which the cylinder 30 is attached. The push rod 26 projects away from the jaw 14 and engages a mounting block 42 securely attached to the body 10 to provide the reaction base.

In operation, the presence of a non-crushable object again actuates pressure sentitive valves, but in this case, fluid from the rear part 30a of the cylinder is fed to the front part 30b, any excess volume being stored in an accumulator.

Retraction of the jaw 14 is achieved due to the periodic pressure caused by the reciprocating motion of the jaw 12.

Again the motor is stopped when the jaw 14 is withdrawn and the piston must be reset and the motor restarted before further use.

It will be appreciated that various modifications can be made while staying within the scope of the invention.

Claims

1. A jaw crusher comprising a pair of converging jaws, a first, reciprocating jaw being provided with means for a reciprocal driving movement towards a second, non-reciprocating jaw, said second jaw being provided with a hydraulic cylinder and piston arrangement for moving said second jaw away from said first jaw when a non-crushable object is encountered.

2. A jaw crusher according to claim 1, in which the second jaw is pivoted at its upper end such that the lower end can be swung away from the first jaw by the hydraulic arrangement.

3. A jaw crusher according to claim 1 or 2, in which an automatic pressure sensing device, mounted in the hydraulic cylinder, is provided such that the presence of a non crushable material can be detected.

4. A jaw crusher according to any of claims 1 to 3 in which the pressure sensing device is used to actuate the hydraulic arrangement to move the second jaw.

5. A jaw crusher according to any of claims 1 to 4 in which, the hydraulic arrangement is such that when a non-crushable object is detected, hydraulic fluid is vented from one part of the cylinder while fluid is pumped under pressure to another part of the cylinder so as to positively move the piston and withdraw the second jaw.

6. A jaw crusher according to any of claims 1 to 4, in which the hydraulic arrangement is such that the presence of the non-crushable object causes fluid to be transferred from one end of the cylinder to the other due to the reciprocating action of the first jaw being transmitted via the object to the second jaw, any surplus fluid being expelled from the cylinder being drained away.

7. A jaw crusher according to any of claims 1 to 6, in which the actuation of the hydraulic arrangement causes the driving means to be disengaged,

8. A jaw crusher as hereinbefore described with reference to and as illustrated in the accompanying drawings.