Patent GB-383800-A (GB)
Title: Improved pneumatic hammer
IPC: B21J7/24
Filed: 1932-01-21
Abstract: 383,800. Pneumatic hammers. SCHATT, C., 95, Avenue Albert Giraud, Brussels. Jan. 21, 1932, No. 1899. Convention date, Sept. 3, 1931. [Class 83 (iv).] A pump-piston hammer has its regulating valve 9 arranged in a sleeve 3 which can be moved to close ports leading to the tup-cylinder 7 and open others to the atmosphere. The valve is moved axially by a rack and pinion 11 and hand or foot levers. In the position shown in Fig. 1 the upper ends 4a, 7a and the lower ends 4b, 7b of the cylinders 4, 7 are connected directly by ducts 9a, 9b and powerful blows are delivered, the upper stroke being cushioned by a plunger 8a closing a hole 14b and freedom of the rebound being ensured by a non-return valve 14d. The space 14, which is permanently connected by a duct 14a to a chamber 12, Fig. 2, is at the same time connected by a duct 9f to a chamber 13 open to the atmosphere. If the valve 9 is moved down slightly the spaces 4a, 7a, and 14 are all connected to the atmosphere by a duct 9d, Fig. 13, and the space 4b is connected by ducts 9h, 17a, Fig. 14, chamber 17, duct 17b, Fig. 15, to a space 9j between oppositely-acting non-return valves 9m, 9n so that air is drawn by the piston 2 from the atmosphere, through the chamber 13 and duct 9q, and forced through duct 9k into the space 7b to hold the tup up. If the valve 9 is moved further down the space 4b is connected with the space 9j and air is drawn from the atmosphere through the chamber 13, duct 9u, Fig. 15, and the valve 9n and forced through the valve 9m, ducts 9k, 17a, chamber 17, ducts 17d, 9s to the spaces 7a, 12 to hold the tup down. If it is desired to reduce the force of the blows the sleeve valve 3, Figs. 2 and 3, is rotated to restrict ports 3a, 3b, leading to ducts 5, 6 and open somewhat ports 3d, 3f to ducts 13<1>a, 13<1>b leading to a chamber 13<1> connected to the atmosphere. If the valve 3 is turned further the tup stops while the piston 2 moves freely. If it is desired to charge a reservoir in order to deliver strong single blows, the valve 3 and a valve 35 are turned into the positions shown in Figs. 24 and 25 so that air is drawn into the space 4a from the atmosphere through a non-return valve 19 and then forced through non-return valve 23, ducts 3d, 22, Fig. 32, non-return valve 26, duct 3f and space 4b which is expanding but at a lower rate than the space 4a is closing, the excess air passing through a duct 3b, non-return valve 29 and duct 28 to a reservoir. While the air is being drawn into the space 4a that in the space 4b is delivered to the reservoir through the valve 29 &c. as before and also through the valve 29 and ducts 38, 35<1>b, 34, 3h, 6, 9b, Fig. 25, to the space 7b. The air in the space 7a, Fig. 24, is at the same time discharged through ducts 5, 9a, 3g, 33, 35<1>a, 37, and chamber 13. If, without altering the position of the valve 3, the valve 35 is placed in the original position shown in Figs. 2 and 3 air is still forced into the reservoir 32 hut the spaces 7a, 7b are cut off. If the valve 35 is then turned in the opposite direction the space 7b is connected to the atmosphere through ducts 9b, 6, 3h, 34, 35<1>b, 39, 13, Fig. 25, and the space 7a to the reservoir through ducts 9a, 5, 3g, 33, 35'a, 36, 32, Fig. 24, and 28, Fig. 25, thus giving one strong blow. The duct 32 is directly connected to the ducts 28, 38, 36 but not with the ducts of the valve 19. The piston 2 is reciprocated by a pivot 40, links 41, 42, Fig. 32, crank-shaft 45, fast pulley 46, belt 54, Fig. 1, and motor 48.