Abstract: According to the invention, a car, for a transporter system, is provided, as means for detecting the close proximity of another car, with a device operated alternately as a signal transmitter and as a receiver and a plurality of plates at sides of the car, at least one plate, for example that of the leading side, being connected to the said device to serve as a receiving plate when the device is operating as a receiver and at least one plate being so connected to serve as a transmitting plate when the said device is operating as transmitter. Advantageously, switch means automatically changes over the connections of the plates to the said device in dependence upon the direction of travel. The output of the device when operating as a receiver may interrupt the driving of the car upon the detection of another car within a predetermined proximity.

Abstract: A system for detecting a leak in a line consists of an apparatus for detecting a drop to a predetermined pressure in the line; and, once the predetermined pressure is reached, an output is developed by the pressure-sensing apparatus. A bi-state circuit responsive to the output from the detecting apparatus has a first state when no leak is present and a second state when the predetermined pressure is detected. A switching circuit has its input connected through the bi-state circuit. A timing circuit develops a signal at its output after a predetermined time and applies this signal to a bi-state gate circuit. A nonleak detector is coupled to the output of the bi-stable gate circuit to indicate that no leak is present in the system.

Abstract: Apparatus for warning of the failure of a sump pump comprising an electrical alarm connected in an electric circuit, a switch for closing the circuit to activate the alarm, and a movable float positioned in the sump for actuating the switch when the water level in the sump reaches a height indicative of sump pump failure.

Abstract: An alarm sensor device having two separable portions. One portion is adhesively attachable to the surface of an object. The other section is supplied with a flow of regulated energy. A measurable energy coupling is provided between the two portions and the system is designed so that the act of physical separation of the two sections is detected so as to activate an alarm system. The result is a protective device in the form of an anti-theft alarm system for preventing unauthorized removal of an otherwise movable object from a specific physical location.

Abstract: A computer keyboard circuit for preventing development of fallacious signals by bouncing or chattering of the keyboard switch contacts, which circuit includes means for delivering a proper output signal to one of several output lines in response to actuation of one of the keyboard switches from a first normal condition to a predetermined actuated condition, and operable to then prevent delivery of an additional output signal to any of the output lines until complete return of the switch to its normal position. To achieve this result, each keyboard switch has two contacts responsive to actuation of the switch to its two different conditions respectively, and the circuitry requires that the switch return the entire distance from one contact to the other in order to condition the apparatus for production of a second output signal.