Abstract: A barrier lifter apparatus comprising a scissors structure having L-shaped clamping elements, a pair of L-shaped tongs, a bar connecting each of the tongs, a pair of linking elements, rods connecting the pair of tongs and the linking elements, and an apertured plate on the rod between linking elements for hoisting. The apparatus can be either semi-automatic with a latched handle or automatic with a ratcheting-cam action device.

Abstract: A pipe lifter with lockable and releasable scissors grip structure, for laying large pipes. The apparatus includes a solid stabilizing plate over cooperating tongs, the base of the plate being capable of rotating about an axis parallel to the central axis of the pipe. The pipe lifter has reinforced linkage members, and multiple ribs between tong pairs, as well as multiple sets of cooperating tong pairs; thus the lifter is capable of withstanding tremendous torsional forces while safely navigating the piping into even very narrow trenches. The device includes a one-piece handle/latch assembly that a helper may operate safely, i.e., while maintaining a distance from any potential pinch points.

Abstract: A work zone intrusion alarm system which sounds a siren to warn highway workers in the event a vehicle enters a work zone. Workers may thus react to errant vehicles in time to avoid injury. The work zone intrusion alarm system is composed of a series of pneumatic sensing lines arranged within a highway work zone adjacent a perimeter separating the work zone from oncoming traffic. The sensing lines are connected at junction boxes which include pressure switches. A warning alarm including a siren is activated by the pressure switch upon the compression of a sensing line when driven over by an errant vehicle.