Abstract: A hardhat mount assembly (12) is provided for mounting a speaker device (14) on a hardhat (10), that allows adjustment of the speaker device position to allow the worker to choose a comfortable position. The mount assembly includes an inner mount part (50) for mounting on the hardhat, a linkage (100) having an upper end pivotally connected to the inner mount part and a lower end pivotally connected to the speaker device, both pivot connections having pivot axes extending in forward and rearward directions. One inner mount device includes a pair of wings (52, 54) with Velcro (74) on their inner surfaces that attach to Velcro pads (80, 82) that have been mounted with contact adhesive on a side of the hardhat. Another inner mount device includes a pair of plates (210, 212) with adjacent edges (214, 216) hinged together and distant ends (220, 222) that can be latched together to clamp a sweatband (202) of the hardhat lining between them.

Abstract: A 2-way radio system for use by a driver of a vehicle such as a motorcycle, enables operation of the PTT (push-to-talk) switch to transmit voice communications, without requiring the driver to raise his/her hand to a PTT switch button on the 2-way radio and without requiring a cable connection. A self-contained separate PTT control unit (40) lies at the driver's finger for operation by the finger without taking the driver's hand off the steering bar (12). During operation, the unit transmits a short range radio signal (70) to a PTT receiver (90) on the 2-way radio to switch the radio to the transmit mode. The PTT control unit can be mounted on the driver's finger or on the steering bar.

Abstract: A marker is provided for use by emergency service personnel entering a room of a building, to keep the door from latching closed while he/she searches the room, and later help him find the door to exit the room, and to indicate to other rescuers that a search is in progress or has been completed. The marker includes a housing (12, FIG. 1) and a door clamp (14) mounted on the housing and constructed to fit on a door to prevent complete closing of the door. The housing holds an audible alarm generator (20) which generates sound beeps to help a searcher find the door in an environment of thick smoke. With the door clamp holding the door ajar, the sound beeps can be heard from outside the room, so another searcher can determine that a search is in progress. The alarm is settable to generate a different pattern of sound beeps, to indicate that a search is in progress, or has been completed. It also generates light flashes. The door clamp can include a length of wire that extends around the outer edge of a door.

Abstract: A cable retraction system is described which includes a windup reel (16) and power springs (24, 26, 28) that urge the reel to turn and wind up a signal-carrying cable (20). An outer end (25) of each power spring is bent about 180.degree. to form a hook that projects through a slot (72) in a windup drum (36) of the reel. A screw (44) projects through a lug (38) at the end of a cable wire, through a hole (71) in the spring, and into a threaded insert (50) set in the windup drum. A stationary axle (30) at the center of the reel, comprises a dielectric body (71) and a plurality of conductors (73, 75, 77) embedded in the body, each conductor having an outer end (58, 60, 62) at the end of the body to connect to wires of a second cable, and each conductor having an inner end (74, 76, 78) lying at the periphery of the axle and attached to an inner end ( 32) of a spring.

Abstract: A marker is provided for use by emergency service personnel entering a room of a building, to keep the door from latching closed while he/she searches the room, and later help him find the door to exit the room, and to indicate to other rescuers that a search is in progress or has been completed. The marker includes a housing (12, FIG. 1) and a door clamp (14) mounted on the housing and constructed to fit on a door to prevent complete closing of the door. The housing holds an audible alarm generator (20) which generates sound beeps to help a searcher find the door in an environment of thick smoke. With the door clamp holding the door ajar, the sound beeps can be heard from outside the room, so another searcher can determine that a search is in progress. The alarm is settable to generate a different pattern of sound beeps, to indicate that a search is in progress, or has been completed. It also generates light flashes. The door clamp can include a length of wire that extends around the outer edge of a door.

Abstract: A headset is provided, of a type which includes a pair of earmuff devices at opposite ends of a head band, which automatically switches an electronic circuit on or off when the headset is placed on the head or taken off, in a simple and rugged construction. Each earmuff device is of the type that includes a largely rigid housing (24, FIG. 3) and a soft resilient cushion (30) mounted on the housing and designed to receive the ear of the wearer and press against the side of the wearer's head which surrounds his ear. A switch (54) connected to the circuit includes an actuating device (60) that is depressed and released along with the cushion. One type of switch (54) is a mechanical type whose actuator device (60) has a front end lying against a rear side (64) of the cushion to be deflected and operate the switch when the cushion is rearwardly deflected during placement on the wearer's head. Another switch includes an electrically conductive element (92, FIG.