GB205522A - Improvements in or relating to ordnance breech mechanism - Google Patents

Abstract

205,522. Dawson, Sir A. T., Buckham, Sir G. T., and Asbury, D. F. April 19, 1922. Ordnance breech mechanism.-Relates to power-operated mechanism of the type in which separate piston-andcylinder elements are employed for rotating the breechscrew and swinging the carrier, and consists in arranging that during the opening of the breech the operation of the unlocking element is aut.omatically followed by the opening operation of the carrier-swinging element and vice versa during the closing of the breech. The invention is shown applied to the breech mechanism described in Specification 6739/12, the power element D, D<1> for rotating the screw being pivoted between the crank pin c<5> of the usual radial crank-shaft C<2> and a spigot C' on the carrier C, and the power element E, E<1> for swinging the carrier being pivotally connected by pins e<1>, e<2> to a bracket e on the gun and a carrier bracket E<2> respectively. Fig. 4 shows the means whereby the power elements are connected to the main pressure and exhaust pipes G<2>, G<3> respectively. To permit of the use of rigid pipes whilst allowing the carrier to swing freely, the pipe e<5> leading to the cylinder E and the pipes c<2>, c<3> leading to each end of the cylinder D are connected to sleeves f<1>, f, f<2>, which can swivel coaxially with the carrier on the spigot ends F, F<2> of the pipes F<4>, F<3> leading from the control-valve casing G. The control valve G<1> can be set by a handle g' to three positions.- (1) for opening the breech, in which the pressure port g<2>, Fig. 4, is connected by a passage G<1x>, Fig. 18, with the port g<4>, and the exhaust gort g<3> is connected with the port g<5> through the space G<x>, (2) for closing the breech, in which the port g<2> is connected to the port g<5> and the port g<3> to the port g<4>, and (3) for by-passing the liquid during hand-working in which the ports g<4>, g<5> are connected, the ports g<2>, g<3> being blocked. A movable stop prevents the handle g<1> being moved into the by-pass position inadvertently. When the pressure from the mains is not available, a handpump G<4>, Fig. 4, is utilized. A dash-pot buffer device in the cylinder E brakes the opening movement of the carrier. When the breech-screw is unlocked, the crank pin c<5> is almost on the dead centre position relatively to the crank shaft C<2> and a roller c<6> can then ride on a control-arc C<7> during the swinging of the carrier. The arc serves during the closing movement of the carrier to prevent locking rotation of the screw until the carrier is nearly closed. For hand-working, the hinge pins of the piston-and-cylinder elements can be readily removed to enable the elements to be swung aside and reattached in inoperative positions. A hand-lever C<8> is then attached to the crank-shaft, the hand-lever having a guard to cover the hole for the hinge pin of the piston rod D<1>. For swinging the carrier by hand, a screw gear operated by a hand-wheel H is provided, the hand-wheel and gear being swung aside for power working.