A tamper-resistant sash window lock includes a housing, a shaft, a cam, and a lever member. An interior surface of the housing wall that defines a cavity. A portion of the interior surface of the housing wall is curved about a hole in the housing, with a distal end of the wall portion formed into a lock surface. The shaft is rotatably mounted in the hole, and a hub of the cam is rotatably mounted on the shaft. The cam has a cantilevered arm with a lock surface and an engagement surface. The lever member is fixedly secured to the shaft, for a first side thereof to engage and drive the cam hub in a first rotational direction into a lock position when the shaft is actuated in the first rotational direction, so the lock surface of the cantilevered arm engages the lock surface of the housing preventing forced entry.

A tamper-proof lock includes: a housing, shaft/handle, cam, lever, spring, and plate. The shaft is pivotally mounted in a housing orifice, with the cam pivotally mounted to the shaft. The cam has first and second shaped openings at first and second respective radial positions, and an arcuate recess. The lever is secured to the shaft, and has a protrusion that alternately engages each of first and second ends of the arcuate recess to respectively/selectively drive the cam to rotate/counter-rotate in first and second directions, into locked and unlocked cam positions. The spring biases the plate for a protrusion thereon to be respectively received within each of first and second shaped cam openings, when aligned therewith at those cam positions, and for a curved surface of the plate to be correspondingly received within first and second curved cam recesses, respectively, when aligned therewith, which facilitate withdrawal of the plate protrusion.

A lock lever structure includes a shaft; a cam attached to the shaft to fit a different-shaped portion of the shaft to prevent rotation of the cam in a circumferential direction of the shaft, the different-shaped portion having a different shape in cross section from a round portion of the shaft; a lever having an inner hollow cylindrical portion larger than an outline of the shaft and attached to the shaft to be rotatable in the circumferential direction of the shaft; a spring attached to the shaft to press the cam and the lever in an axial direction of the shaft; and a retainer attached to the shaft to retain the spring, the cam, and the lever to the shaft. The cam has at least two valley portions. The lever has a contact portion to contact the cam. The contact portion has a base shape.

A door latch activator system for a trailer or truck body coupled to a door latch, including: a plunger installed in a path of the door latch; a switch configurable into one of an open or closed position by the plunger; and a pneumatic valve configured to control flow of pressurized air through the pneumatic valve depending on the position of the switch, wherein the plunger is moved toward or away from the roller switch by the door latch operating in the path, which activates the pneumatic valve to control the pressurized air flowing through the pneumatic valve.

A tamper-proof lock includes: a housing, shaft/handle, cam, lever, spring, and plate. The shaft is pivotally mounted in a housing orifice, with the cam pivotally mounted to the shaft. The cam has first and second shaped openings at first and second respective radial positions, and an arcuate recess. The lever is secured to the shaft, and has a protrusion that alternately engages each of first and second ends of the arcuate recess to respectively/selectively drive the cam to rotate/counter-rotate in first and second directions, into locked and unlocked cam positions. The spring biases the plate for a protrusion thereon to be respectively received within each of first and second shaped cam openings, when aligned therewith at those cam positions, and for a curved surface of the plate to be correspondingly received within first and second curved cam recesses, respectively, when aligned therewith, which facilitate withdrawal of the plate protrusion.

A door latch activator system for a trailer or truck body coupled to a door latch, including: a plunger installed in a path of the door latch; a switch configurable into one of an open or closed position by the plunger; and a pneumatic valve configured to control flow of pressurized air through the pneumatic valve depending on the position of the switch, wherein the plunger is moved toward or away from the roller switch by the door latch operating in the path, which activates the pneumatic valve to control the pressurized air flowing through the pneumatic valve.

A lock lever structure includes a shaft; a cam attached to the shaft to fit a different-shaped portion of the shaft to prevent rotation of the cam in a circumferential direction of the shaft, the different-shaped portion having a different shape in cross section from a round portion of the shaft; a lever having an inner hollow cylindrical portion larger than an outline of the shaft and attached to the shaft to be rotatable in the circumferential direction of the shaft; a spring attached to the shaft to press the cam and the lever in an axial direction of the shaft; and a retainer attached to the shaft to retain the spring, the cam, and the lever to the shaft. The cam has at least two valley portions. The lever has a contact portion to contact the cam. The contact portion has a base shape.

A door latch activator system for a trailer or truck body coupled to a door latch, including: a plunger installed in a path of the door latch; a switch configurable into one of an open or closed position by the plunger; and a pneumatic valve configured to control flow of pressurized air through the pneumatic valve depending on the position of the switch, wherein the plunger is moved toward or away from the roller switch by the door latch operating in the path, which activates the pneumatic valve to control the pressurized air flowing through the pneumatic valve.