Patent GB-191404080-A (GB)
Title: Improvements in and connected with Fluid Pressure Brakes for Ordnance.
IPC: F41A25/02
Filed: 1914-02-17
Granted: 1914-06-18
Abstract: 4080. Krupp Akt.-Ges., F. March 7, 1913, [Convention date]. Recoil apparatus.-Relates to fluid-pressure brakes for ordnance provided with means for regulating the length of recoil, the limit of recoil being effected by completely closing the opening through which the fluid flows, and consists in obviating the shock produced at the end of a short recoil by partially covering that part of the opening for the brake fluid that remains in action for braking the last stage of the longest recoil. The hollow piston comprises two parts B, B', Fig. 1, screwed together, and, with the piston-rod B<2>, moves in the brake cylinder A. A ring C mounted to rotate, but not to move longitudinally, upon the piston has projections c<1> engaging helical grooves a<1> in the brake cylinder, to prevent fluid from passing directly through the grooves. An annular valve D is rotatably mounted on the part B of the piston, and has projections d<1>, Fig. 3, engaging grooves a<2>, Fig. 2, in the brake cylinder, which grooves are parallel to the longitudinal axis of the cylinder. An extension d<2> on the valve D engages beneath a corresponding extension b<3> on the part B'. The extensions b<3>, d<2> and the part B of the piston are formed with openings b<4>, d<3>, b<5> respectively, which connect the grooves a<1> with the space b' in the piston, the openings b<4>, d<3> being shaped as shown shaded and in dotted lines, respectively, in Fig. 5, and the openings b<5> being at least as great as the crosssectional area given by the openings b<4>, d<3> at any adjustment of the brake. When the parts occupy the positions shown in Figs. 1 and 5, no part of the opening b<4> is covered either by the inner wall of the cylinder A or by the valve D, and the parts thus have their maximum recoil before the opening b<4> is closed by the inner wall of the cylinder. To obtain the shortest recoil, the piston-rod B<2>, and with it the piston B, B<1>, is rotated counterclockwise by hand, or automatically, the cylinder wall thus covering the opening b<4> to about half itslength measured transversely to the brake axis. The annular valve remains stationary and thus also covers part of the opening b', thereby producing a smaller passage for the fluid than if the valve were absent. The constriction is so selected that the recoil energy is completely neutralized when the openings are completely closed by the cylinder wall. For intermediate lengths of recoil, the piston-rod B<2> is given a less rotation. To obtain smooth running-out with any length of recoil, a throttling-bar E is employed projecting into a central boring b<8>, and passages b<9> in the piston are controlled by a spring non-return valve F. The abutment G for the spring f<1> is bored to the same diameter as that of the rod E, and grooves e<1> are formed in the rod E to allow the fluid that passes into the space b<8> during recoil to pass to the space b<6> during run-out, the valve F being closed. An arrangement whereby the braking of the run-out is reduced for short recoils, or for large elevations, comprises a passage b<10>, Fig. 3, connecting the space within the valve F with a passage d<4> in the inner wall of the rotary valve D, a radial passage d<5> leading from the passage d<4> to a point a small distance from the edge a<3> of the groove a<1>. For short recoils, the fluid from the space b<8> is thus able to pass through the grooves e' and also along the course b<10>, d<4>, d<5>, a<1> to the outer cylinder. The passage d<5> is closed slightly before the run-out is completed.