A flow sensing apparatus for providing an indication of the presence of an exiting flow stream from a coal processing plant cyclone includes a probe member disposed in the edge of the flow stream, an electronic sensing circuit cooperatively arranged with the probe member in order to provide either a high or a low level signal, depending upon whether the probe member is being contacted by the exiting flow stream or whether such contact is not being made. A display light is cooperatively arranged ...

A liquid level alarm apparatus for a tank of a vehicle comprising a float having a permanent magnet, a pair of electrical contacts opened or closed in response to the proximity of said magnet, and a stopper for limiting the upward movement of the float, said contacts being connected by leads to an electric circuit comprising an alarm device. The contacts are maintained in a closed condition when the liquid in the tank is above a predetermined level and the contacts are separated, which operates ...

An active ultrasonic perimeter intrusion detection system comprises an elongated flexible electret tape capable of being stored on and deployed from a reel or the like and connectable when deployed to a signal generator operating at ultrasonic frequencies and to a receiver having a signal processing and alarm capability. The tape comprises an electret layer sandwiched between relatively fixed and movable conductive strips and lies flat on a surface adjacent to the area to be protected such as th...

A vehicle burglar alarm system having an internal control switch. The control switch is located in a non-passenger compartment of the vehicle and a delay mechanism is provided to prevent sounding of an alarm during the period required to activate or de-activate the alarm.

An electric switch for use in a braking fluid pressure fault alarm device for a vehicular dual brake system, which device includes a body having a cylinder, a piston slidably inserted in the cylinder and receiving front and rear wheel braking fluid pressures for sliding movement from its inoperative position to its operative position in response to leakage of either of the braking fluid pressures, and an electric alarm circuit for generating an alarm signal when deenergized. The electric switch ...

A brake lining wear warning system comprising a probe which becomes nonconductive when the wear of a brake lining reaches a critical value, a holding circuit adapted to be placed in a set condition in response to the nonconduction of the probe and remain in the set condition even after the termination of the nonconduction of the probe, and a warning device for giving a warning when the holding circuit is in the set condition.

A device including a detector means for the wheels of a vehicle to detect a reduction in the tire air pressure below a specified level, alarm holding circuits which may be operated under the control of the detector to energize an alarm device and hold it in the energized state, and a reset signal producing circuit operable at the vehicle speeds exceeding a predetermined level for intermittently producing a signal to reset the alarm holding circuits. The device informs the driver of any unusual r...

A device for providing an optical indication of the pressure condition in a pressurized member, such as a pneumatic tire. A housing having a window therein carries a reflective surface, such as a mirror, which is mounted on a movable flap. One end of a plunger pin holds the mirror in alignment with the window with the other end of the pin resting on a diaphragm assembly which communicates with the internal pressure of the member. Light from a light source is directed in the window and under norm...

A multi-axled traction vehicle is equipped with a plurality of means for sensing the speeds of its respective drive axles, and control means is provided for producing a predetermined warning signal if the sensed speed of any one of the axles is under a predetermined low threshold level. In addition, means is provided for disabling the control means if none of the sensed axle speeds exceeds a predetermined higher threshold level, thereby preventing the production of a warning signal when the vehi...

Apparatus to detect deceleration of a motor vehicle having an automatic transmission includes a first electrical switch operated by release of pressure from the accelerator pedal and a second electrical switch operated by application of pressure to the brake pedal. A detector device having an output signal is connected in parallel with the electric switches. The output signal of the detector device is employed to vary the spark timing of an internal combustion engine. In a modification, the elec...