Abstract: An interlocked infrared detector wall switch which prevents use of the full "on" position that bypasses the infrared sensor, but permits changeover by service personnel to use the full "on" position. The slide switch on the wall switch assembly is partially covered by a snap-on interlock plate so that it can not be moved to the full "on" position. Removal of the interlock plate requires a screwdriver for leverage within an opening at the bottom of the interlock plate, but this opening is covered by the decorative switch plate, so that removal of the interlock plate is impossible without first removing the covering decorative plate. Casual disabling of the interlock is thereby prevented.

Abstract: A positive pressure focus lock for closed circuit video cameras. The carrier block to which the image sensing device is attached is moved parallel to the lens axis for focusing images at close range because of the use of a lens normally focused at infinity or changes of focus required by system tolerances. The carrier block motion is accomplished by the use of two cams on a single fixed axis. The cams press against the carrier block and move the carrier block on guide rods as the cam shaft is turned. To prevent play in the movement of the carrier block due to manufacturing tolerances on the various parts, the cams are held tightly against the carrier block by leaf springs instead of using a conventional fixed cam guide. The leaf springs' ends are attached to the carrier block and the springs act as a second bearing surface for the cams while keeping the carrier block tight against the cams regardless of tolerances or shock and vibration.

Abstract: A focusing system for closed circuit video cameras. A carrier block to which the image sensing device is attached is moved parallel to the lens axis for focusing images at close range because of the use of lenses normally focused at infinity or changes of focus required by system tolerances. The carrier block motion is accomplished by the use of two cams on a single shaft. The cams press against the carrier block and move the carrier block on guide rods as the cam shaft is turned. In order to attain two focusing ranges, the cam shaft itself is located within two pivoting saddles rather than being fixed. The saddles pivot on a fixed shaft which permits the entire focusing mechanism to be moved in one step between two preset positions. Each of the two positions is selected to be appropriate for one of two lenses.

Abstract: A vertical motion detector for a TV system motion detector. The circuit operates by delaying each motion indicator signal by multiple units of the time required for one full horizontal line sweep. If vertical motion occurs, the delayed indicator will output from the delay at the same time another indicator occurs. These signals are fed to multiple AND gates so that several coincident signals are required to produce an alarm. A switching circuit permits selection of the number of vertical motion indicators required for an alarm.

Abstract: A digital control circuit uses a single infrared detector to control the clock pulse on a digital counter so that the sensitivity control is based on the length of time a change in infrared radiation persists. A pyroelective detector is located in a voltage divider and the intermediate voltage of the divider is digitally compared to the intermediate voltage in a fixed divider as a digitaly controlled pulse is applied to both dividers. Either an increase or a decrease of infrared radiation causes the digital circuit to permit the counter to be activated.

Abstract: A digital infrared detector circuit which converts changes in detector current to time varying pulses and uses feedback to adjust the coincidence of a reference signal with the trigger signal to accommodate to circuit variations caused by changes in infrared detector sensitivity or ambient temperature. To supply a highly accurate feedback reference signal an internal high frequency oscillator is used for feedback control and counted down to furnish the reference signal. The conversion from detector current to time is accomplished by using the detector to discharge an accurately charged capacitor and measuring the time to recharge the capacitor.

Abstract: A motor driven panoramic mounting for cameras which provides an automatic pan range and the ability to go beyond the automatic range under manual control. The automatic mode is restarted regardless of the position of the camera at the restart. Four mechanical actuators are used which move a star shaped cam that turns another cam upon which a reversing switch actuator rides. The reversing switch cam has a central flat positioned within the movement differential zone of the limit switch so that it remains in its last condition due to hysteresis, whereas the outer end flats actuate the switch to reverse the camera motion.

Abstract: A motion detector which compares the video signal from a camera to a camera signal from an earlier scene and produces an alarm signal if an edge of any object has changed its position, but protects against false signals. A phase detector is used to sense movement in only the edges of objects and a vertical coincidence circuit requires object movement in several vertical video lines to prevent false signals from such small items as raindrops. Several adjacent horizontal areas must also show movement in order to activate an alarm.

Abstract: A digitally controlled ambient light detection circuit for an infrared intrusion detector. A light dependent resistor is used as a charging circuit for pulse driven capacitor on the input of a digital buffer circuit so that the time of reaching the threshold voltage of the buffer varys with the light falling on the light dependent resistor. The buffer output is then compared to a reference pulse which is synchronized with, but delayed from, the capacitor charging pulse. If the buffer output occurs after the reference pulse it indicates low light, and an output signal is generated to activate the infrared intrusion detector.

Abstract: An electrical switch actuator mechanism which has an accurately aligned position. The actuator operates printed circuit board pushbutton switches by depressing a spring finger to operate each pushbutton. Each of the fingers has a raised land with a precisely angled slope which a rub bar on the back of the actuator handle rides upon to depress the spring. However, the angled slope and the spring action of the leaf spring also act backward against the rub bar to precisely locate the position of the actuator handle so that a group of such switches are properly aligned when the switches are in the same position.

Abstract: A focusing electrode structure for a photomultiplier tube which optimizes the tube operation. One or more focusing electrodes located between the photocathode and the first dynode are configured in the shape of substantial sections of a spheroid dome with the smaller opening nearer to the photocathode. In the preferred embodiment three focusing electrodes are used with their sizes increasing and their voltages decreasing as they approach the photocathode.