GB2206910A

GB2206910A - Coal cutting machine

Info

Publication number: GB2206910A
Application number: GB08716235A
Authority: GB
Inventors: Jerome Anthony Emery
Original assignee: Coal Industry Patents Ltd
Current assignee: Coal Industry Patents Ltd
Priority date: 1987-07-10
Filing date: 1987-07-10
Publication date: 1989-01-18
Anticipated expiration: 2007-07-10
Also published as: GB2206910B; GB8716235D0

Abstract

A coal cutting machine has a rotary cutter drum mounted on a machine adapted to travel the length of a coal face, the drum has picks mounted thereon for cutting coal from the face, and includes at least one electrically operated sensitive pick engaging the coal face and to produce an electric signal proportional to the cutting force on the pick. The electrically operated sensitive pick is supplied with power from a power source carried by the drum and including generating means, such as a pendulum generator, arranged to generate power on movement of the drum.

Description

IMPROVEMENTS RELATING TO COAL CUTTING MACHINES This invention relates to a coal cutting machine of the kind having a rotary cutter drum mounted on a machine adapted to travel the length of a coal face, the drum having picks mounted thereon for cutting coal from the face, and including at least one electrically operated sensitive pick arranged to engage the coal face and to produce an electrical signal proportional to the cutting force on the pick.

Coal cutting machines equipped with sensitive picks are extremely useful for steering a machine and ensuring that it keeps within the coal seam. As soon as the forces on the sensitive pick change for example when the pick is cutting out of the coal into a rock face this change can be immediately noted and the horizon on which the machine is steered can be altered so that only coal is cut. This steering can be done either manually or automatically.

There is a problem in providing power to operate the electrically sensitive pick and also to obtain the signals from the pick to control or indicating apparatus situated away from the coal cutting machine itself. Initially slip rings were used to transmit power from a power source to the pick and also slip rings were used to transmit the signals from the pick back to the indicating or recording apparatus away from the machine. This was a cumbersome method and improvements were made for example as is disclosed in our British Patent No. 1 407 236 where the sensitised pick feeds its signals to a local transmitter incorporated in the drum and this transmitter sends at radio frequency the signals to a receiver situated away from the machine.Although this solution d does s away with the need for a slip ring set and trailing cables to transmit the signal away from the machine it still requires a power source through a slip ring to get power to the machine.

Proposals have been made to do away with the slip rings by incorporating in the machine in the area of the drum a local battery operated power source. This power source can supply power to the senitised pick direct and can also operate if necessary a radio transmitter. The use of batteries has a disadvantage that the life of the batteries are finite and they have to be replaced at regular intervals. These intervals may not always be convenient with shift times and maintenance periods and this can lead to the loss of coal production. Furthermore access to the batteries can be difficult when the machine is in a working position.

It is an object of the present invention to provide an improvement to a coal cutting machine which overcomes these disadvantages.

According to the present invention in a coal cutting machine of the kind having a rotary cutter drum mounted on a machine adapted to travel the length of a coal face, the drum having picks mounted thereon for cutting coal from the face, and including at least one electrically operated sensitive pick arranged to engage the coal face and to produce an electric signal proportional to the cutting force on the pick, the electrically operated sensitive pick is supplied with power from a power source carried by the drum and including generating means arranged to generate power on movement of the drum.

The power source preferably comprises a battery connected to supply power continuously to the pick and any radio means associated with the pick and the generating means is arranged to charge the battery source. Alternatively the generating means may supply the power directly to the pick and to any transmitting means.

The generator means is preferably connected to the machine drum with the rotary part of the drum acting as the armature of an electric generator and the spindle as a stata or vice versa.

Alternatively the generator means may operate on the pendulum principle wherein an oscillating arm, mounted on the drum moves relative to the rotation of the drum and operates as a stata or armature of an electric generator thus transmitting current to the battery or to the pick direct.

In one example of the invention a coal cutting machine is mounted on an armoured face conveyor and is hauled along this conveyor. The machine has an arm which carries at its end a rotating drum and this drum a plurality of picks secured to vanes on the drum.

One at least of these cutting picks has mounted behind it and protruding slightly beyond it a sensitised pick of the kind as is shown for example in our British Patent 1 407 236. This pick is mounted for movement depending on the cutting force which the pick is exerting on the face against which it impinges and this force varies with the hardness of the material being cut. Coal being relatively soft will cause a small displacement of the pick whereas if the pick strays into the rock boundary of the coal seam a different signal will be produced due to there being a greater force on the pick from the harder rock.

The drum carries in it a battery and this battery supplies current directly to the pick and also to a radio transmitter associated with the pick. Mounted in the drum is a pendulum system which is caused to oscillate on movement of the drum in a manner akin to a self winding watch. The pendulum can be used to operate a generator means. Current is thereby generated every time there is relative movement between the pendulum and drum this current is fed directly to the battery to maintain a trickle charge to the battery.

The rate of charge is designed to be such that the drain on the battery from operation of the sensitised pick and the transmitter does s not exceed the charging current to the battery.

It will be appreciated that by use of a local generating means within the drum there is no need for the battery to be removed or connected for charging between shifts. This enables the operation of the cutting machine to be continued for long periods satisfactorily without any need for maintenance of the electrical supply to the sensitised pick.

Claims

Claims:

1. A coal cutting machine of the kind having a rotary cutter drum mounted on a machine adapted to travel the length of a coal face, the drum having picks mounted thereon for cutting coal from the face, and including at least one electrically operated sensitive pick arranged to engage the coal face and to produce an electrical signal proportional to the cutting force on the pick, in which the electrically operated sensitive pick is supplied with power from a power source carried by the drum and including generating means arranged to generate power on movement of the drum.

2. A machine as claimed in Claim 1 in which the power source ccmprises a battery connected to supply power continuously to the pick and any radio means associated with the pick and the generating means is arranged to charge the battery source.

3. A machine as claimed in Claim 1 in which the generating means supplies the power directly to the pick and to any transmitting means.

4. A machine as claimed in any preceding claim in which the generator means is connected to the machine drum with the rotary part of the drum acting as the armature of an electric generator and the spindle as a stator or vice versa.

5. A machine as claimed in Claim 1, 2 or 3 in which the generator means operates on the pendulum principle wherein an oscillating arm, mounted on the drum moves relative to the rotation of the drum and operates as a stator or armature of an electric generator thus transmitting current direct direct to the battery or to the pick.

6. A coal cutting machine substantially as hereinbefore described.