Patents Assigned to Contronic Controls Limited
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Patent number: 4356474Abstract: A digital alarm system of the type having first and second electrically conductive loops connected by an alarm switch. The alarm switch is normally open, but can be closed when an alarm state exists to electrically short one loop to the other. Currents are generated in each of the loops for use in detecting either the closing of the alarm switch or the occurrence of a fault in one of the loops. Resistors are connected to each of the loops for use in detecting the presence or absence of the currents. A first pair of transistor switches alternatingly short-circuit one resistor then the other; and a second pair of transistor switches, synchronized with the first pair, alternatingly short the ends of one loop then those of the other so that when the alarm switch is closed the first pair of transistor switches simultaneously short-circuit both resistors even if a fault occurs anywhere in one of the loops.Type: GrantFiled: March 6, 1981Date of Patent: October 26, 1982Assignee: Contronic Controls LimitedInventors: Peter Humphries, Paul Aeberli
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Patent number: 4201982Abstract: An intrusion alarm system has a number of satellites each connected to a master by an unshielded cable having only four conductors, namely two power conductors, a drive signal conductor which supplies drive to the satellite transmitter and the satellite control circuit, and an alarm conductor. When an intrusion is detected by a satellite, its control circuit transmits a high level alarm signal on the alarm conductor to the master and also sets a latch in the satellite. The master has a rocker switch which an investigator turns off when he arrives at the supervised premises. This turns off the drive signal to the satellite and causes a counter in the master to send a set of interrupting counting pulses to the satellites on the drive conductor. Each satellite has a counter which counts the pulses if that satellite's latch has been set and sends a pulse back to the master on the alarm conductor immediately after the count associated with that counter.Type: GrantFiled: April 20, 1978Date of Patent: May 6, 1980Assignee: Contronic Controls LimitedInventor: Peter E. Humphries
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Patent number: 4138674Abstract: An intrusion alarm system has a number of satellites each connected to a master by an unshielded cable having only four conductors, namely two power conductors, a drive signal conductor which supplies drive to the satellite transmitter and the satellite control circuit, and an alarm conductor. When an intrusion is detected by a satellite, its control circuit transmits a high level alarm signal on the alarm conductor to the master and also enables, but does not operate, a speaker in the satellite. The master has a rocker switch which an investigator turns off when he arrives at the supervised premises. This turns off the drive signal to the satellite. The control circuit of the satellite that caused the alarm responds by sounding its speaker, enabling determination of where the alarm occurred.Type: GrantFiled: February 22, 1977Date of Patent: February 6, 1979Assignee: Contronic Controls LimitedInventor: Peter E. Humphries
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Patent number: 4129856Abstract: An intrusion alarm of the kind in which a radiation field is transmitted in an area to be supervised; the reflected field is received and compared with the transmitted field, and a comparison signal is produced the frequency of which is indicative of the speed of movement of an object in the supervised area. A signal processor receives the comparison signal and generates an alarm if the comparison signal contains components in a selected frequency range. The processor includes a unique filter block which removes unwanted frequency components outside the range. The filter block includes a pulse generator which generates a constant amplitude pulse train, each pulse corresponding to a pulsation of the comparison signal, and control elements which control the duty cycle of the pulse train so that as the frequency of the comparison signal increases, the average level of the pulse train first increases and then decreases.Type: GrantFiled: November 15, 1976Date of Patent: December 12, 1978Assignee: Contronic Controls LimitedInventor: Peter E. Humphries
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Patent number: 4101875Abstract: An intrusion alarm system has a number of satellites each connected to a master by an unshielded cable having only four conductors, namely two power conductors, a drive signal conductor which supplies drive to the satellite transmitter and the satellite control circuit, and an alarm conductor. When an intrusion is detected by a satellite, its control circuit transmits a high level alarm signal on the alarm conductor to the master and also enables (but does not operate) a speaker in the satellite. The master has a rocker switch which an investigator turns off when he arrives at the supervised premises. This turns off the drive signal to the satellite. The control circuit of the satellite that caused the alarm responds by sounding its speaker, enabling determination of where the alarm occurred.Type: GrantFiled: November 15, 1976Date of Patent: July 18, 1978Assignee: Contronic Controls LimitedInventor: Peter E. Humphries
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Patent number: 3980998Abstract: An ultrasonic intrusion alarm is described. In the specific embodiment described with reference to the drawings, the alarm includes a transmitter and a receiver both mounted in a cylindrical housing. The housing is turnably held in contact with a base by a grill cloth. In use the housing is turned to direct the transmitter. The grill cloth prevents the area protected by the alarm being visually determined from externally of the alarm.Type: GrantFiled: September 5, 1975Date of Patent: September 14, 1976Assignee: Contronic Controls LimitedInventor: Lawrie G. McIntosh