Abstract: An automatic hook lock which is electrically and manually operable and is particularly adapted for manual, motorized or remotely controlled sliding gates to which it is attached on the surface thereof or within the interior thereof. The lock consists of a rectangular metal box containing an electromagnetic solenoid with relative magnetic plate, a cylinder lock with a key, a hook and a system of five rocker levers actuated by a spring-compressed plunger. The lock is assembled in such a way that every time the solenoid receives an electrical impulse, the magnetic plate is moved to release the system of rocker levers. The combined action automatically provides the freeing and elevation of the hook. The inverse, blocking action occurs automatically with the closing of the gate. The mechanical, manual opening of the lock is achieved using a key.

Abstract: A single air navigation instrument provides sequential direct readings of true-course, magnetic-course, magnetic-heading, distance and flight times; determines in value and sense the altitude correction corresponding to actual barometric pressure at sea-level, and provides solutions of the wind triangle.The longitudinal borders of the instrument carry a scalimeter having distance scales graduated in nautical miles. A first rotating goniometer inserted between the upper and lower faces of the instrument protrudes enough to permit its rotation by thumb or finger action. The center of the first goniometer is transparent and carries an arrow visible through windows on both sides of the instrument, permitting the positioning of the instrument directly on navigational charts. The reverse side of the disc carries the inner scale of a circular logarithmic slide-rule.