Controlling system

Application filed May 14,

To alt whom it may concern:

Be it known that I, Charles W. Wyman, a citizen of the United States, residing at Claremont, in the county of Sullivan and 0 State of New Hampshire, have invented certain new and useful Improvements in Controlling Systems, of which the following is a full, clear, and exact specification.

My invention relates to controlling syΒΙΟ terns, and more particularly to controlling systems for electrically operated mining mechanisms.

In many mines which are known as gassy mines, there is a sufficient amount of com13 bustible gas at the working face so that it is dangerous to employ any mechanism at the face which could possibly, by. reason of sparking or arcing, cause the ignition of the combustible mixture present. In mines of 20 this type, by the use of alternating current motors in which the sparking resulting from commutation is avoided, it has been found possible to largely reduce the danger but in all commercial machines up to the present 25 time it is still found necessary to employ a circuit making and breaking mechanism of some kind upon the machine and as a result, although these parts are very carefully enclosed, an explosion might occur were the cas30 ing opened or tampered with so as to permit access of the explosive mixture to the space within which sparking takes place.. It is the object of my invention to provide an improved controlling mechanism in which, 35 while controlling means is arranged upon the mining machine so that the latter may be controlled with all the customary convenience, still all circuit making and breaking mechanism is arranged as such a distance 40 from the face that the danger of explosions is eliminated. Other objects and advantages of my invention will hereinafter more fully appear.

In the accompanying drawings I have 45 shown for purposes of illustration one form which my invention may assume in practice.

In these drawings —

Fig. 1 is a plan view of a portion of a mine showing a mining machine at work 50 and a possible disposition of the controlling mechanism.

Fig. 2 is a simplified wiring diagram showing the circuits of the illustrative disclosure of my invention.

It. will be observed that the mining ma1823. Serial No. 638,823.

chine 1 shown herein is working along a longwall face and that it is connected by a long flexible cable 2 with a box 3 and thence by other cable means 4 under control of a main line switch δ with the power circuits in 8V the main entry of the mine which is shown at 6, the distance between the chamber in which the machine is working and the parts 3, 4, 5 and 6 being under ordinary conditions one or two hundred feet perhaps, or under ¢5 certain circumstances possibly even more.

The power circuit is a three-phase transmission system and the three wires thereof are illustrated at 10, 11 and 12 in Fig. 2. These are connected by the three-pole switch 5 o through suitable fuses 13, 14 and 15 with a set of three wires 16, 17 and 18 extending into the controller box 3. Within the box 3 is a second three-pole switch 19 whose blades 20, 21 and 22 cooperate with contacts 75 23, 24 and 25 to connect the lines 16, 17 and 18 with wires 26, 27 and 28 which are arranged within the cable 2 and lead to the motor 29 upon the machine, it being evident that when the main line switch is closed, SO upon closing of the controller switch, the motor will be caused to run. The main control switch 19 is provided with an operating shaft 30 which carries the knife blades 20, 21 and 22 and which when caused to ?-5 oscillate in the proper manner closes and opens the circuits of the motor. For . the purpose of imparting the necessary oscillatory movement to the shaft 30.it is provided with a cross arm 31 to which there are 90 secured a pair of armature elements 32 and 33 with which in turn there cooperate a pair of magnet coils respectively numbered 34 and 35, all this mechanism .being located within the box 3. Wires 37 and 38 are 95 tapped off of the wires 17 and 18 within the box 3 and are arranged in the cable 2 within which they extend to the machine 1 and constitute a circuit through a coil 39 whose purpose will shortly become apparent. This 100 coil is mounted for oscillatory movement with respect to a pivot 40 and may be moved in either direction from a central position by a control lever 41. The magnet coils 34 and 35 are connected together by a wire 105 42 at one end and this wire is connected by a wire 42' within the cable 2 to a wire 43 connecting the ends of a pair of coils 44 and 45. The coils 44 and 45 are arranged radially with respect to the pivot 40. The 110

1,566,460 other ends of the coils 44 and 45 are connected by wires 46 and 47 also extending through the cable 2 with the other ends of the coils 34 and 35. It will be observed that by reason of the alternating current flowing in the wires 37 and 38 the coil 39 will act as one of the coils of a transformer and will induce a current in the coils 44 and 45, which current will be equal since the resistance and other characteristics of the two halves of the, so to speak, balanced circuit including the coils 34 and 35. 44 and 45 is equal.

From the description so far given the mode of operation of this mechanism will be readily understood. Let it be assumed that it is desired to start the motor. The switch 5 will be closed. The lever 41 will be moved in a counter-clockwise direction about its pivot 40. As a result, the ceil 39 will be moved to a position opposite the coil 45 and the very small current which was previously induced in the coil 44 will be further diminished, while that induced in the coil 45 will be largely increased. As a result the energization of the coil 35 will be increased while that of the coil 34 will be reduced. Accordingly, the armature 33 will be strongly attracted while the attraction of the armature 32 will be diminished and the shaft 30 will be rocked to cause the knife switch blades 20, 21 and 22 to engage the contacts 23, 24 and 25, and so current will flow from the lines 10, 11 and 12 through the lines 26, 27 and 28 and the motor will be operated. When is is desired to stop the motor, all that will be necessary will be to mo ve the lever 41 in the opposite direction and, this having been done, the coil 44 will then have the greater current induced in it and this current flowing through the coil 34 will cause the armature 32 to swing the switch 19 to open position. It will be apparent that by suitably coning the switch 19 it will be pos;o cause it to effect a series of movements by the use of the magnets such as t connect the motor windings in star len in delta and finally to disconnect them entirely from the line, appropriate latch means being used to effect this sequence of operations. A, single coil arrangement could obviously be used to effect circuit closing with spring or -weight opening, also. It will also be evident that instead of having the circuits for moving the switch directly controlled in the manner described herein, the coils 34 and 35 might control a relay which would control primary magnets for operating the switch 19.

While I have in this application specifically described one form which my invention may assume in practice, it will be understood that this form of the same is used for purposes of illustration and that the invention may be modified and embodied in other forms without departing from its spirit or the scope of the appended claims.