Abstract: A protective device for fire hydrants comprises a generally domed shaped member having a shape conforming to the bonnet of a fire hydrant and including a socket configured to receive an operating nut thereof. The protective device has a diameter too great to be engaged by readily available pliers, wrenches and the like but may be actuated by use of a chain wrench or a friction wrench. The device includes no separate moving parts which may freeze or jam and may be retrofitted to existing fire hydrants by welding or brazing.

Abstract: A probe for sensing the position of an object relative to a reference point includes a contact tip extensibly mounted on a probe body by means of a piston assembly which transmits minimal force to the object through the tip after the tip contacts the object. The piston assembly includes a fluid driven piston which is normally spring biased to a retracted position. The tip is mounted on one end of a shaft which is slidably mounted on the piston so as to be displaced relative to the piston only after the tip contacts the object. The other end of the shaft forms the core of an LVDT which transforms linear displacement of the shaft into electrical signals indicative of the position of the object relative to the reference point.

Abstract: A cable connector includes at least two electrically conductive slip ring members with freely rotatable contact surfaces which are mutually frictionally engaged with one another. Provision is made for selectively forcing the contact surfaces into highly pressurized engagement so as to lock them together during application of current through the cable. The present invention finds particular utility as a rotary joint cable connector for a pneumatically operated spot welding gun.

Abstract: A hand-held, manually operable gauge for measuring the gap between opposing surfaces of a pair of spaced parts includes a pair of reciprocable gauge fingers insertable into the gap and respectively shiftable into engagement with the parts by a lever pivotally mounted on a handle. One of the fingers is stationarily mounted on the handle while the other finger is secured to a plunger slidably mounted on the handle and driven by the lever. Linear displacement of the plunger is translated by a rack and pinion to rotary motion for operating a potentiometer whose setting corresponds to the magnitude of the gap. A switch carried by the handle and activated by the lever produces a signal proportional to the potentiometer setting, which signal is delivered to a device for visually displaying the magnitude of the gap. A lost motion mechanism permits continued displacement of the lever after the gauge fingers have contacted the parts.

Abstract: An LVDT displacement transducer and a probe actuation arrangement integrated into a probe assembly. The probe assembly includes a tubular housing within which is mounted at one end an LVDT and within the other the probe actuation arrangement. In the preferred embodiment, an air pressure actuator arrangement is utilized and comprises a stepped diameter probe extension shaft having a smaller diameter section joined to the LVDT core element, and extending through a bulkhead bushing into a pressure chamber, the larger diameter section of the shaft passing out through the opposite end of the housing and serving to mount the probe sensor contact. The differential diameter of the stepped probe extension shaft is subjected to air pressure via an air fitting communicating with the air chamber and which acts against a return spring to enable self actuation of the probe extension shaft and attached core element.

Abstract: A pneumatic powered probe having a rod that extends into contact with the surface of a workpiece to gauge its position includes optics and electronic circuitry for generating a binary signal proportional to the position of the probe end. The circuitry includes a parallel channel optical mask that moves with the rod between a set of light emitting diodes and a set of photo-transistors, both supported on a circuit board. Transistor circuitry supported on the board converts the outputs of the photo-transistors into a binary parallel code which may be transmitted to a remote location upon receipt of an enabling signal by a plurality of gates in the device. The rod is connected to a cylinder which cooperates with a piston fixed to the device housing. Air admitted into the chamber between the piston and cylinder force outward motion of the rod. The optical mask is supported on the cylinder and moves with it relative to the diodes and photo-transistors to generate the position related signal.