GB2077680A - Safety apparatus for a conveyor - Google Patents

Abstract

Safety apparatus for use with a conveyor 12 for preventing personnel being conveyed beyond a specified location on the conveyor, the apparatus including a tunnel 11 which extends from said location for a predetermined distance upstream of said location so as to provide a cover for the conveyor to prevent access to the length of the conveyor contained within the tunnel other than through the mouth of the tunnel. A guard may be provided at the mouth of the tunnel which when activated by a person on the conveyor switches off the power to the conveyor driving motor. Also a flap 30 may be provided which, when a catch 32 is released, falls clown to the chain-line position and engages a flight on the conveyor to stop the conveyor quickly. <IMAGE>

Description

SPECIFICATION Safety apparatus The present invention relates to safety apparatus for use with conveyors for preventing personnel from being accidentally conveyed into dangerous machinery. The present invention is particularly, but not exclusively, suitable for use with conveyors used in the coal mining industry which deliver coal to mineral breakers or hoppers.

Aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figure 1 is a plan view of apparatus according to the present invention.

Figure 2 is a side view of the apparatus shown in Fig. 1.

It is common practice in the coal mining industry to provide pull or trip wires extending along one or both sides of conveyors which when pulled actuate a switch which cuts off power to the motor driving the conveyor and also machinery being fed by the conveyor.

Unfortunately, when such switches are actuated the conveyor continues to run for a period of time due to the inertia within the conveyor system. This movement of the conveyor, normally referred to as overrun, can be dangerous in that it may be sufficient to carry a person into the machinery being fed by the conveyor. If the machinery includes moving parts such as a mineral breaker, then that too could be overrunning and consequently the person would be delivered into the machinery which effectively is operational.

The present apparatus 10 includes a tunnel 11 which encloses a conveyor which feeds material to be broken to a mineral breaker 20.

The mineral breaker may be of any known type, for instance as disclosed in our U.K.

Patent Application Number 7903879.

The tunnel 11 is made up of tunnel sections 21 and a tunnel section 22, the length of the tunnel 11 being preferably such as to extend along the conveyor a sufficient distance to allow for overrun of the conveyor, i.e.

the length of the tunnel is preferably at least as long as the distance travelled by the conveyor after the power to the conveyor drive motor has been switched off. Thus if a person is about to enter the mouth 23 of the tunnel and the power to the conveyor drive motor is cut off, then continued motion of the conveyor would be sufficient to carry that person into the mineral breaker. Accordingly it is proposed to provide trip or pull wires along either side of the tunnel and mineral breaker in order to enable operatives to quickly inactivate the conveyor and mineral breaker should they see a person entering the mouth of the tunnel.

Additionally, it is also proposed to provide switch actuation means such as a guard at the mouth of the tunnel which may be activated by a person on the conveyor in order to cut off power to the conveyor and breaker drive motors as he enters the tunnel.

Once a person has entered the tunnel stopping of the conveyor and breaker by switching off the power to the drive motors is ineffective due to overrun.

Accordingly, in accordance with another aspect of the present invention we provide stop means which preferably takes the form of a flap 30 which is pivotally mounted in the roof of the tunnel 11. The flap 30 is maintained in a raised position by means of a catch 32 which on actuation releases the flap 30 to enable it to fall under gravity on its lowermost position as shown by broken lines in Fig. 2.

In its lowermost position the flap 30 deflects material being carried by the conveyor upwardly and out of the opening 31 normally filled by the flap 30 when in its raised position. Additionally, if the conveyor is of the type having spaced flights 33 (only one of which is shown in Fig. 2) as normally provided in armoured flexible conveyors, the terminal end 40 of the flap will abut against one of the flights 33 thereby causing the conveyor to rapidly stop and may even result in snapping of the conveyor.

Preferably a switch means (not shown) is sited in the path of travel of the flap 30 so that as it moves to its lowermost position it operates the switch means to cut off power to the conveyor and breaker drive motor.

The flap 30 is constructed from a suitable rigid material such as steel and is constructed so as to be capable of withstanding the necessary loads imposed on its by suddenly engaging one of the flights 33 of the conveyor. The flap 30 is therefore of a very sturdy construction. Additionally, the pivotal connection is constructed so as to be robust enough to withstand these loadings.

The terminal end of the flap 30 is preferably inclined as shown to enable the flap 30 to bite its way through material being conveyed to the breaker.

In order to actuate the catch means it is presently preferred to extend pull wires 50 within the tunnel 11 along either side from the catch means to a fixed anchor 51. The connection of the pull wires 50 to the catch means and their location within the tunnel are arranged so that if material being conveyed along the conveyor happens to snag with the pull-wires the catch means are not actuated.

Additionally, the pull-wires 50 are also arranged to be capable of being deflected by build-up of material within the tunnel without causng actuation of the catch means.

Accordingly the arrangement is such that the catch means is actuated only when either pull-wire is pulled in a direction opposite to the direction of movement of the conveyor.

Thus if a person enters the tunnel he may reach up to either side of the tunnel and pull a wire 50 which will cause the flap to fall and result in the conveyor being rapidly brought to a halt.

In order to enable a person outside the tunnel 1 to actuate the catch means there are provided additional pull wires 60 which extend from the catch means and along the both outer sides of the tunnel 11.

The catch means shown in the drawings includes a latch member 70 which is mounted on a rotatable shaft 71. The latch member 70 normally resides under the flap 30 to hold it in its raised position.

A pair of arms 72 extend from the shaft 71 on the inside of the tunnel to which the pull wires 50 are connected. The shaft extends upwardly through the top of the tunnel and a pair of arms 74 extend from the shaft 71 to which the wires 60 are attached. The arrangement is such that pulling on wires 50 or 60 cause rotation of shaft 71 thereby moving the latch member 70 to a position whereat it no longer supports the flap 30.

Although in the illustrated embodiment only one tunnel 11 is shown on the feed side of the mineral breaker, it is envisaged that a similar tunnel 11 incorporating a flap 30 may be positioned on the outlet.

Claims (7)

1. Safety apparatus for use with a conveyor for preventing personnel being conveyed beyond a specified location on the conveyor, the apparatus including a tunnel which extends from said location for a predetermined distance upstream of said location so as to provide a cover for the conveyor to prevent access to the length of the conveyor contained within the tunnel other than through the mouth of the tunnel.

2. Safety apparatus according to Claim 1 wherein the length of the tunnel is at least equal to the amount of overrun of the conveyor.

3. Safety apparatus according to Claims 1 or 2 including switch means for rendering the conveyor inoperative.

4. Safety apparatus according to Claims 1, 2 or 3 including stop means positioned adjacent to and upstream of said location, the stop means being operative to positively engage the conveyor.

5. Safety apparatus according to Claim 4 wherein the stop means comprises a flap pivotally mounted on the roof of the tunnel, the flap normally residing in a raised inoperative position and when actuated falls to engage the conveyor.

6. Safety apparatus according to Claims 3, 4 or 5 wherein the switch means and/or stop means are actuated by pull-wires extending longitudinally and along the inside and/or outside of the tunnel.

7. Safety apparatus for use with a conveyor substantially as described with reference to and as illustrated in the accompanying drawings.