US1444827A - Controlling system for mine-blasting operations - Google Patents

Description

Feb. 13, 1923. 1,444,827

5. F. BRIDWELL ET AL CONTROLLING SYSTEM FOR MINE BLASTING OPERATIONS Filed May 25 1921 WITNESSES ATTORNEYS Patented Feb. 13, 1923.

UNETED STATES SAMUEL FREDRICK BRIDWELL AND JOHN FORSYTH KENNEDY, OF TERRE HAUTE,

INDIANA.

CONTROLLING SYSTEM FOR MINE-BLASTING OPERATIONS.

Application filed May 25, 1921. Serial No. 472,590.

T 0 all whom it may concern:

Be it known that we, SAMUEL F. BRID- wnLL and JOHN Fonsr'rrr KENNEDY, citizens of the United States, and residents of Terre Haute, in the county of Vigo and State of Indiana, have invented certain new and useful Improvements in Controlling Systems for Mine-Blasting Operations, of which the following is a specification.

The present invention relates to mining. It relates particularly to mine blasting operations in which a plurality of blasting shots are electrically fired in the different work places of the mine at one operation.

In blasting operations of this character, as hereto-fore carried out, a number of shots are simultaneously fired in the various working places, or working rooms, of the mine, by connecting in the same circuit the electrically operated squibs or detonators of the cart-ridges and then closing the circuit after the miners have reached a supposed place of safety. This method has Several disadvantages which our invention is'designed to overcome. In the first place no positive in dication is given the operator that all cartridges have been exploded, and accidents may easily originate through the assumption that this is the case when, as a matter of fact, one or more cartridges remain unexploded. Moreover, since the method referred to produces simultaneous explosions of the cartridges, there is no way of distributing the shocks of the explosions, and, consequently, the number of shots which can be fired at one operation is restricted by the destructive effects of the explosion waves. Our invention is designed to overcome these disadvantages and others incident to the method heretofore employed.

The invention comprises a system of control whereby an operator located outside the mine can select and fire a shot in any one of a number of previously prepared rooms of the mine. In its preferred form, the invention consists of a transmitter located in the power house or other suitable location adjacent the mine shaft, a receiver at a. central location in the mine mechanically connected with the transmitter to move in synchronism therewith, said receiver adapted to select and close any desired c1rcuit of a plurality of circuits leading to the cartridges in the various: working rooms. The system further includes a telephone transmitter located at a central position with reference to the working rooms connected with a receiver at the transmitting station, whereby the operator of the system can positively know whether or not a selected cartridge has exploded. The transmitter is turnished with suitable indicationscorresponding to the various circuits controlled by the receiver so that the operator can select any circuit and fire the shot cont-rolled thereby.

Referring to the accompanying drawing, which shows in a diagrammatic way our system of control, A represents the transmitting station and B, the receiving station. The transmitter consists of a dial 2 having suitable indications thereon, over which is adapted to move a pointer 3. The pointer is connected with a shaft on which is rigidly mounted a sprocket wheel 4: over which passes a sprocket chain. The receiver B is exactly similar to the transmitter except that, instead of having indications on the dial, it has a series of contact buttons spaced in exact accordance with the indications of the transmitter, the receiver arm, corresponding to the pointer of the transmitter being adapted to make electrical contact with the buttons as it passes thereover. There is, as shown, a mechanical connection between the sprockets of the transmitter and receiver consisting of wires and sprocket chain sections guided through the shaftand tunnels by suitable sprocket idlers. The contact buttons of the receiver are severally connected to one terminal of the cartridges in the various work rooms, the other terminal of said cartridges being connected with a common connection from one pole of a battery, the other pole of said battery being connected, through a normally open switch 5 at the transm'tting station, with the contact arm of receiver B. The rooms, as indicated, are numbered consecutively and connected with correspondingly numbered contact buttons of the receiver, the transmitter having indications consisting of numbers corresponding to those of the receiver. A telephone transmitter 6 is placed at any suitable location in the mine where it will be affected by the sound waves generated by an explosion in any room, said transmitter being wired to a receiver at the transmitting station.

The method of operating the system may be briefly described. After the charges have been prepared in the various working rooms and the detonators connected up, the mine is cleared of men. An operator at the transmitter A then places the telephone receive-r over his ears and manually moves pointer 33 successively over the indications on the dial, switch 5 being in closed position. The charges in the various rooms are thus successively exploded. In case a charge should fail to explode, which fact will be communicated to the operator by his failure to hear the explosion, the particular room in which the failure occurs will be noted for future investigation. In case it is not desired to fire all the shots at one operation, or in case it is desired to select certain non-consecutive rooms for blasting, switch 5 is left open, and then the operator can select any desired room by simply moving the pointer 3 to the number of that room and thereafter closing the switch 5.

It will be understood that in practice the circuit wires will be enclosed in cables from which the individual wires will be led out to the various compartments or working rooms.

It will be apparent from the above dis closure that our system of control provides an exceedingly etlicient and safe method of controlling the blasting operations. Its use obviates the necessity of any one being in the mine when the blasting operations are taking place, thus preventing loss of life from gas, premature explosions, windy shots, black damp, etc. Any number of shots may be prepared and fired at one operation, as our system produces successive explosions, thus distributing the shocks of the explosions. Y

lVhile we have described a preferredapparatus for carrying out our method, we do not consider that our invention is limited to the particular apparatus described, as it is obvious that various modifications may be made in the particular apparatus described without departing in the least from the spirit oi. our invention. For example, it isobvious to those skilled in the signalling art that the receiver could be operated electrically from the transi'nitter, either by a motor movable in synchronism with the transmitter, or by some ot the various kinds of step by step mechanism. We prefer to use a meclnmical connection between the transmitter and receiver, because of its reliability, simplicity and cheapness.

We claim:

1. An apparatus for firing mine blasts, comprising a transmitter located adjacent the mouth of the shaft and including a dial bearing suitable indications, a pointer rotatable thereover and a sprocket wheel rigid with said. pointer, a receiver located in the mine centrally with rejlerence to a, plurality of working rooms, said receiver consisting of a disk bearing a number of contact buttons correspondingto the indications on said dial, a contact arm rotatable thereover and adapted to make electrical contact therewith and a sprocket wheel rigid with said arm, a connection between said sprocket wheels comprising wires and sprocket chain sections suitably guided in the shaft and various passages of the mine, a source of electric energy having one pole connected with said arm through a switch located at the transmitting station, the other pole of said source of energy being connected with a common conductor extending along the mine passages, adjacent the working rooms, conductors severally connected with the contact buttons of said receiver and adapted to be connected with one terminal of the blasting cartridges in the working rooms, the other terminals thereof being connected with said common conductor.

2. A system for controlling mine blasting operations, comprising a transmitter located outside the mine, a receiver located in the mine mechanically connected with said transmitter to move synchronously therewith, and electrical connections controlled by said receiver for selectively firing a plurality of shots in different parts of the mine.

SAMUEL FREDRICK BRIDWELL. JOHN FORSYTH KENNEDY.

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