GB940263A - Improvements relating to safety harnesses - Google Patents

Abstract

940,263. Aircraft &c. safety harness. J. MARTIN. Feb. 12, 1960 [Feb. 12, 1959], No. 4993/59. Heading A3V. [Also in Division B8] A safety harness is restrained with respect to the seat by a strap 11 which is wound on a spring drum 9 on the seat back, passes between relatively movable clamping jaws 20, 21 in a unit 4 at shoulder level, then through a yoke 15 on the harness and is finally secured to an apertured lug 12 releasably retained in a slot 18 in the seat by a locking bolt 13. The upper jaw 21 is normally held in cocked position to allow for movement of the strap 11 in either direction, but when the seat or occupant is subjected to a sudden change in velocity, inertia operated means pivot the jaw 21 towards the fixed jaw 20 so as to grip the strap 11. The jaw 21 is mounted on a shaft 22 to one end of which is secured a crank arm 24 which is pivoted at its other end 27 to an axially telescopic spring-loaded link 25 having its other end pivotably anchored at 26 to the side of the unit 4. Under normal conditions the pivot 27 lies above a line 28 through the pivot 26 and shaft 22 so that the spring in the link 25 retains the jaw 21 in a cocked position; on a sudden change in velocity the jaw 21 is pivoted downwardly due to the inertia of its own mass 23 so that the pivot 27 lies below the line 28 and the spring helps to snap the jaw into its clamping position. In a modification the inertia mass 23 is separate from the jaw 21 and located on a separate lever operating the jaw. A manual control lever for locking or releasing the strap 11 may be mounted on the seat pan and may operate the shaft 22 through linkage and telescopic torque mechanism (Fig. 11, not shown). Specifications 848,208 and 854,769 are referred to.