Alarm circuitry

Claim 2

Alarm circuitry for use in a structure having entrance means for detecting unauthorized entrance to the structure, comprising: a sensor operatively associated with the entrance means and responsive to an unauthorized entry to change said sensor from a first state to a second state, a latch circuit coupled from said sensor for assuming a reset state during said first state and a set state for at least the duration of said second state, said latch circuit having a reset input, a first lamp means coupled from said latch circuit and that is on when said latch circuit is in the set state and is off when said latch circuit is in the reset state, indicating means responsive to the state of said latch circuit for indicating an alarm condition in response to the set state thereof, an enabling circuit including a first switch means, said enabling circuit having one output coupling to said indicating means for enabling operation thereof when the structure is to be protected against unauthorized entrance and for inhibiting operation thereof at other times, second lamp means responsive to the state of said latch circuit, second switch means including a first contact for permitting said second lamp means to be on when said latch circuit is in the reset state thereby indicating that said sensor is in its first state and said latch circuit is in its reset state in readiness for use, and a reset line coupling from another output of said enabling circuit to the reset input of said latch circuit, said reset line for holding said latch circuit reset when said enabling circuit is inhibiting operation of said indicating means, said second switch means having a second contact disposed in said reset line for opening said reset line when said second lamp means is permitted to be on.

Claim 3

Alarm circuitry as defined in claim 1 comprising a first transistor coupled from said latch circuit to said first lamp means and a second transistor coupled from said first transistor to the first contact of said second switch means.

Claim 4

Alarm circuitry as defined in claim 2 wherein said first contact is closed causing illumination of said second lamp means when said latch circuit is in its reset state and said second contact is concurrently opened preventing a resetting of said latch circuit.

Claim 5

Alarm circuitry as defined in claim 3 wherein said enabling circuit comprises a third lamp means for indicating the position of said first switch means.

Claim 6

Alarm circuitry as defined in claim 4 wherein said first switch means includes a relay and a switch, said relay having one set of contacts coupled to said third lamp means and a second set of contacts coupled to said reset line.

Claim 7

Alarm circuitry as defined in claim 5 wherein said alarm indicating means includes a relay coupled from both said second transistor and said first set of contacts for maintaining the relay energized when either said second transistor is conductive or when said third lamp is not illuminated.

Claim 8

An alarm circuit for use In a structure having means for detecting unauthorized entrance to the structure, comprising; a sensor operatively associated with the entrance means and responsive to an unauthorized entry to change said sensor from a first state to a second state, power supply means, a first test switch coupled in series with said sensor and power supply means and bieng in an open position with testing, a latch circuit coupled from said sensor for assuming a reset state during said first state and a set state for at least the duration of said second state, said latch circuit having a reset input, a first lamp circuit coupled from said latch circuit and including a lamp that is on when said latch circuit is in the set state and is off when said latch circuit is in the reset state, a second lamp circuit coupled from said first lamp circuit and including a lamp that is permitted to be on when the latch circuit is reset, indicating means coupled from said second lamp circuit responsive to the state of said latch circuit for indicating an alarm condition in response to the set state thereof, an enabling circuit including an on-off switch and bistable means having first and second sets of contacts, said first set of contacts coupling to said indicating means for enabling operation thereof when the on-off switch is on and inhibiting operaton thereof when the on-off switch is off, a second test switch having first and second poles, said first pole for permitting the lamp of said second lamp circuit to be on when said latch circuit is in the reset state thereby indicating that said sensor is in its first state and said latch circuit is in its reset state in readiness for use, and a reset line coupling from the second set of contacts of said bistable means to the reset input of said latch circuit, said reset line for holding said latch circuit reset when said enabling circuit is inhibiting operation of said indicating means, said second pole of said second test switch being disposed in said reset line for opening said reset line when the lamp of said second lamp circuit is permitted to be on.

Claim 9

An alarm circuit for use In a structure having means for detecting unauthorized entrance to the structure, comprising; a sensor operatively associated with the entrance means and responsive to an unauthorized entry to change said sensor from a first state to a second state, power supply means, a first test switch coupled in series with said sensor and power supply means and bieng in an open position with testing, a latch circuit coupled from said sensor for assuming a reset state during said first state and a set state for at least the duration of said second state, said latch circuit having a reset input, a first lamp circuit coupled from said latch circuit and including a lamp that is on when said latch circuit is in the set state and is off when said latch circuit is in the reset state, a second lamp circuit coupled from said first lamp circuit and including a lamp that is permitted to be on when the latch circuit is reset, indicating means coupled from said second lamp circuit responsive to the state of said latch circuit for indicating an alarm condition in response to the set state thereof, an enabling circuit including an on-off switch and bistable means having first and second sets of contacts, said first set of contacts coupling to said indicating means for enabling operation thereof when the on-off switch is on and inhibiting operaton thereof when the on-off switch is off, a second test switch having first and second poles, said first pole for permitting the lamp of said second lamp circuit to be on when said latch circuit is in the reset state thereby indicating that said sensor is in its first state and said latch circuit is in its reset state in readiness for use, and a reset line coupling from the second set of contacts of said bistable means to the reset input of said latch circuit, said reset line for holding said latch circuit reset when said enabling circuit is inhibiting operation of said indicating means, said second pole of said second test switch being disposed in said reset line for opening said reset line when the lamp of said second lamp circuit is permitted to be on.

Claim 10

The circuit of claim 7 wherein said enabling circuit includes a lamp coupled to the first set of contacts and being illuminated when said indicating means is permitted to operate.

Claim 11

The circuit of claim 8 wherein said second test switch is operated to open the reset line, and the first test switch is thereafter opened to test the operation of said latch circuit.

Claim 12

The circuit of claim 9 wherein said first and second lamp circuits each include a transistor.