Alarm sensing and indicating systems

Claim 2

An alarm-sensing and indicating system comprising a circuit which is normally energized from a direct current source, the circuit including in multiple at least one normally open circuit alarm condition sensing means and at least one alarm indicating means wherein the improvement comprises: a. means responsive to current polarity for each of the sensing and indicating means for enabling current flow only upon energization of the circuit with said one or the other polarity, respectively; and b. polarity-changing means connected to the circuit subject to actuation in response to abnormal current in the circuit for changing the polarity of energization of the circuit to activate the indicating devices, comprising: a resistor terminating the circuit, and a relay normally energized at a low level and energized at a higher level to polarity change the circuit in responsive to the actuation of the sensing means and further the relay is operated to an intermediate energization state for supervisory purposes in response to a normal level of current in the circuit and the relay is operated to polarity change the circuit in response to a predetermined high level of current in the circuit.

Claim 3

The invention according to claim 1 wherein a holding circuit is provided for maintaining the relay in an activated position until reset after it has been actuated to pole change the circuit in response to actuation of a sensing device.

Claim 4

The invention according to claim 1 wherein trouble-indicating means is provided for manifesting an abnormal condition of the circuit.

Claim 5

The invention according to claim 1 wherein a second relay is provided for supervisory purposes that is normally energized by the circuit for manifesting continuity in the circuit.

Claim 6

An alarm-sensing and indicating system comprising a circuit which is normally energized from a direct source, the circuit including in parallel at least one normally open circuit alarm condition sensing means and at least one alarm-indicating means wherein the improvement comprises: a. means responsive to the current polarity for each of the sensing and indicating means for enabling current flow only upon energization of the circuit with said one or the other polarity respectively; b. solid state switching means including at least two silicon-controlled rectifiers responsive to a signal indicative of actuation of an alarm condition-sensing means for polarity changing the circuit, and a resistor capacitor means for delivering said signal to the gate of the silicon-controlled rectifiers in accordance with the current in the circuit for gating the silicon-controlled rectifiers to a conductive state, and c. trouble-sensing means for checking the continuity of the circuit including a supervisory relay having its winding connected in parallel with the alarm condition-sensing means and means serially coupled to the relay for rendering passage of current through the relay effective to actuate the relay only upon energization of the circuit with said one polarity.

Claim 7

An alarm-sensing and indicating system comprising a circuit which is normally energized from a direct source, the circuit including in parallel at least one normally open circuit alarm condition sensing means and at least one alarm-indicating means wherein the improvement comprises: a. means responsive to the current polarity for each of the sensing and indicating means for enabling current flow only upon energization of the circuit with said one or the other polarity respectively; b. solid state switching means including at least two silicon-controlled rectifiers responsive to a signal indicative of actuation of an alarm condition-sensing means for polarity changing the circuit, and a resistor capacitor means for delivering said signal to the gate of the silicon-controlled rectifiers in accordance with the current in the circuit for gating the silicon-controlled rectifiers to a conductive state, and c. trouble-sensing means for checking the continuity of the circuit including a supervisory relay having its winding connected in parallel with the alarm condition-sensing means and means serially coupled to the relay for rendering passage of current through the relay effective to actuate the relay only upon energization of the circuit with said one polarity.

Claim 8

The invention according to claim 5 wherein a holding circuit is provided for maintaining the relay in an activated position until reset after it has been actuated to polarity change the circuit in response to actuation of a sensing means.

Claim 9

The invention according to claim 5 wherein a relay is provided for supervisory purposes that is normally energized by the circuit for manifesting continuity in the circuit.