US1126199A - Fire-alarm transmitter. - Google Patents

Description

W. R. HAMILTON.

FIRE ALARM TRANSMITTER.

APPLIUATION FILED APImz. 191s.

1,128,199, Patented Jan.26,1915.

UNITED STATES PATENT OFFIC VILLIAM R. HAMILTON, 0F MONTREAL, QUEBEC, CANADA, ASSIGNOR TO THE DOMINION GRESHAM GUARANTEE & CASUALTY COMPANY, OF MONTREAL, CANADA, A CORPO- RATION OF CANADA.

FIRE-ALARM TRANSMITTER.

Specification of Letters Patent.

Patented Jan. 26, 1915.

T0 all whom it may concern Be it known that I, IVILLIAM R, HAMIL- rroN, of the city of Montreal, in the Province of'Quebec and Dominion of Canada, have invented certain new and useful Improvements in Fire-Alarm Transmitters, of which the following is a full, clear, and exact de- -scriptioir reasons been almost universally operated on closed circuit principle, and require two transmitters, one of which transmits the alarm signal, while the other maintains the system under constant test so as to .send a different signal if any part of the instrument or system except the signal circuit gets out of order. The disadvantage of this arrangement is that a defect in the signal circuits may be equivalent to the operation of the alarm transmitter, so that what should be a trouble signal on these circuits is transmitted as an alarm signal, thus sending to the central station a false alarm. These disadvantages are overcome in the present invention by using only a single transmitter for both the alarm and trouble signals, and so arranged as to be controlled by a single circuit. Any disarrangement of this circuit other than that prearranged for the sending of an alarm signal will transmit a trouble signal only.

In the drawings which illustrate the inventionr-Figure 1 is a front elevation of the transmitter. Fig. 2 is a circuit diagram showing the operating elements connected to the transmitter.

Referring more particularly to the drawings, 5 designates the frame of a spring driven clock movement controlled by a lever 6 carrying a catch 7 movable into and out of the path of the fan 8 to release or stop the clockwork movement. An electro-magnet 9 is provided having low resistance windings 9L and 9b of equal resistance. -These two windings are so arranged that the current liow is in opposite directions, so

that while the current iows through both windings, the magnetism induced by one winding is neutralized by the magnetism induced by the other winding, so that the magnet is denergized and does not draw up its armature l0. This armature is mounted on the lever 6 and is provided with a lever arm 11 projecting into the path of a cam (not shown) mounted behind the signal wheels 12. A small spring 13 is provided to normally hold the armature 10 away from the magnet 9, so that the stop 7 remains in the path of the fan 8.

At a suitable point on the movement, an electro-magnet 111 of higher resistance than the magnet 9 is provided, having an armature 15 carried on one arm of a bell-crank lever 16. The other arm of this bell-crank lover is provided with a pin 17 which is normally in engagement with or in very close proximity to the lever 11. The arm of the lever 16 carrying the armature is provided with a pin 18 positioned to be engaged by a cam 19 carried on the same spindle as the commutator 20. This cam 19 has a recessed portion 21 which is positioned under the pin 18, while the transmitter is at rest, as is clearly shown in Fig. 1.

One transmitter, such as above described, is mounted in each protected building and is connected in series with abattery or other source of energy 22 and with a detecting device, indicated at 23. This detecting device may be of any desired type, such as a galvanometer, relay or like instrument, having a circuit maker 24 adapted to engage a contact 25 when operated and to engage a contact 26 when out of order. The current low from the battery is through wire 27 to winding 9LL of magnet 9, and through the wire 28 to the contact 25. From the contact 25, the 'low is through wire 29 to winding 9b. After passing through the winding 9b, the current flows through wire 30 to the contact 26 and from the contact through wire 31 to the magnet 14C. After passing through the magnet 14, the current returns to the battery through wire 32 in which is inserted the circuit maker 24.

It will be seen from the foregoing that all the elements including the contacts are in series. Tap wires are not used to connect the contacts and circuit maker into the circuit for the reason that the breaking of these taps would not destroy the circuit, so that no indication of disorder would be given. It will be remembered that the magnet 9 is ofvlowresistance and 'the magnet 14 of high resistance,and also that the windings 9a and 9b of the magnet neutralize, so that during current flow through both windings the core is demagnetized. 1t is therefore obvious thatf'if either' lof the windings of the magnet 9 is short circuited, there will be nothing to neutralize the ell'ect of the other winding, so `that the magnet becomes energized and tends to draw up its armature. However, as long as the high resistance magnet 14 remains in i' the circuit, 'there would not be suiiicient current flow through the remaining winding of the magnet 9 Ato energize the same. Therefore, the magnet 14 is arranged as shown in the diagram, F ig. v2, so that when the winding 9b is short circuited the magnet 14 will also be short circuited, and allow the full strength of current flow through the winding 9a. It will be seen at a glance from Fig. 2 that the con-v tact 26 is so vpositioned in the circuit that when engaged bythe circuit maker 24, the magnet 14will be short circuited and that when the contact 25 is engaged by the circuit maker, the magnet 14 and one winding of the'. magnet 9 will be short circuited.

1,. With thefforegoing points in mind, the operation will be easily understood and is as follows The detecting instrument 28 when 1in its normal condition holds ythe. circuit maker 24 midway between the contacts 25y and 26. Any failure of the instrument removes or reduces the holding effect on the circuit maker, vso that it is thrown against the Contact 26 and short circuits the magnet 14- of the transmitter. This magnet releases its armature 15 which drops by gravity and by means of the pin 17 throws the lever l11. This lever is connected through the armaturelO- with the control lever 6 of the transmitter movement, and therefore operates the control -lever towithdraw the stop 7 from the fan, and thus release the' movement which operates the signal wheels 12 to transmit a signal to the central station. Vhen the transmitter has repeated its signal a predetermined number of times, for example, twice, the cam 19 engages the pin 18 and raises the lever 16, thus releasing the lever 11 and permitting the 4spring 13 to shift the control lever 6 and stopA the transmitter movement. The cam now holds :the armature 15. up until the trouble is repaired and the transmitter rewound to bring the notch 21 under the pin 18. If the instrument 23 is operated by the fire or burglar protection circuits, `it throws the circuit. maker 24 against contact 25 so that the winding 9b of magnet `9 and the magnet 14 are' both' shorttcircuited. The magnet 9v now energized by itswinding 9a draws up the armature 10 and releases the transmitter movement, as previously described. The neutrali zation of the magnet 9 by the short circuiting of its winding 9b and the increasing current flow permitted by the short circuiting of the magnet 14, enables the magnet 9 op- 70 erated by its winding 9L to hold up its armature 10 as long as the battery remains active. The transmitter thus continues operating until run .down and sends in its signal a greater number of times than when operater by the magnet 14,\for example, ve times. During this condition, the mechanical restoration of the armature 15 and lever 16 previously explained will have no eifect whatever' on the transmitter, as the magnet 33 9 continues to hold olf the stop of the movement until the transmitter is rewound and set. The magnet 14 being of higher resist-v ance than vthe magnet 9 requires a stronger current to operate it, and will therefore naturally become inoperative owing to battery failure, while there is still ample current to operate magnet 9. Thus, it might happen that with avweakened current, the magnet 14 would be able to hold up its armature, 90 but would not be able to lift the armature to restore the transmitter to normal. Any current strong enough to operate the magnet 14 to hold up its armature would obviously be strong ,enough to enable the magnet 9 95 to hold up its armature. Thus, if the transmitter was operated by the fire detecting device, the magnet 14 would be short circuited and drop its armature, which would operate as previously described to throw the armature 10 against the magnet. -The magnet 9` would then hold it upfwithout difficulty. ThenI a battery becomes very muchweakened, the high resistance magnet 14naturally fails rst and drops its armature irre- 195 spective of the action of any detecting device. If now the detecting device operated the transmitter before the transmitter was re-set and the batteries replaced, there would still be suiiicient current to operate themagnet 9 when the magnet 14 was short circuited, and the transmitter would send in the number of signals remaining between the trouble signal and the alarm signal, which for the instances previously cited would be three times. If any wire is broken, the `circuit is broken and the instrument 23 throws its circuit maker 24 against the contactl 26, thus short circuiting the magnet 14.

In most instances, the device would op- 1.20 erate without the nutralizing winding 9b as the high resistance magnet 14 would pre-` vent an operative current flow through the winding 9a. If, however, an unusually strong battery was installed or the wiring 126 within the kbuilding became charged from another system, the first time themagnet 14 was denergized there would be sufficient current flow to operate the magnet 9, so that an alarm signal would be sent in place 130 of a trouble signal. The neutralizing winding obviates any possible occurrence of this accident, since no matter how great the current flow is the magnet 9 will remain inoperative until one of its windings is short circuited.

The description and drawings must be regarded as purely illustrative and not in any way limitative, since the application of the principle of the invention to different forms of transmitter would obviously make numerous changes in details of construction and arrangement.

I-Iaving thus described my invention, what I claim is l. In a signal transmitter, the combination with a transmitter control device of a high resistance magnet and a low resistance magnet having two windings arranged to neutralize one another, said magnets being arranged to independently operate the control device, a detecting device, and an alarm circuit connecting the high resistance magnet and both windings of the low resistance magnet and the detecting device in series. I

2. In a signal transmitter, the combination with a transmitter control device and a detecting device of a low resistance magnet arranged to operate the control device and to be energized by the operation of the detecting device, a circuit connecting the detecting device and low resistance magnet, a high resistance magnet connected in series in said circuit and arranged to operate the control device independently of the low resistance magnet, and means arranged to maintain the low resistance magnet inoperative during increased current ilow caused by the short circuiting of the high resistance magnet.

3. In a signal transmitter, the combina- Copies of this patent may be obtained for creased current flow caused by short cir'- cuiting of the high resistance magnet.

5. In a signal system, a source of energy,

a detecting device and a transmitter, a high resistance and a low resistance magnet arranged -to independently operate the transmitter, saidlow resistance magnet comprising two coils arranged to neutralize each other during current flow through both, a circuit closable by the detecting device to short circuit the high resistance magnet, and a second circuit closable by the detecting device to short circuit the high resistance magnet and one winding of the low resistance magnet, whereby current iiow through the remaining winding will energize the low resistance magnet.

6. In a signal system, a source of electric energy, a detecting device, a mechanical self-stopping transmitter, a high resistance magnet and a low resistance magnet arranged to independently operate the transmitter, a circuit closable by the .detecting device to short circuit the high resistance magnet whereby the transmitter will be released, a` second circuit closable by the detecting device arranged to energize the low resistance magnet, to release and hold the transmitter in released condition independent of its/self-stopping feature, and a neutralizing cdil on said low resistance magnet arranged to hold the magnet inoperative during short circuited condition of the high resistance magnet, only said neutralizing coil being short circuited simultaneously with the high resistance magnet by the detecting device to enable operative current iiow through the low resistance-magnet.

In witness whereof I have hereunto set my hand, in the presence of two witnesses.

WILLIAM R. HAMILTON.

Witnesses:

STUART R. W. ALLEN, G. M. MORELAND.

five cents each, by addressing the Commissioner of Patents,

Washington, ID. C.

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