GB986389A - Forging hammer - Google Patents

Abstract

986,389. Forging. EUMUCO AKTIENGESELLSCHAFT FUR MASCHINENBAU. June 12, 1961, No. 21196/61. Addition to 983,403. Heading B3H. An hydraulically operated hammer according to the parent Specification has a pair of tups 2, 3 interconnected by an oscillatable liquid link. The tups are connected to pistons 6, 7 whose spaces 8, 9 are in continuous communication with a container 10 filled exclusively with pressure liquid and which is charged by the constant delivery pump 11 through one-way valve 13. A by-pass valve 14 is operated when the hammer is idle. Cylinder spaces 18, 21 communicate with a reversing valve 17 which is connectible through a shut-off valve 23 with the reservoir 24. To initiate the forward stroke, pump 11 pressurizes container 10 until pressure controller 30 actuates valves 17, 23 to place cylinder space 18 in communication with the container 10 and space 21 with the reservoir. Thus upper tup 2 moves downwardly due to the differential pressure on its piston, and lower tup 3 is raised by the pressure in chamber 9. Shortly before impact one of the tups actuates an electric device which reverses valve 17 whereby space 18 is opened to exhaust and space 21 to the container 10. Thus upper tup is raised by the pressure in space 8 and the lower tup falls by gravity in opposition to the differential pressure on its piston 7. Buffer pistons 27 operate in spaces 26 connected through one-way valve 28 with the container 10 whereby the impact energy of the lower tup assists in pressurizing the container. A safety valve 31 is fitted. In another embodiment, Fig. 2 (not shown), horizontal counterblow hammers have the inner cylinder spaces of their pistons connected continuously to the container and the outer spaces to the reversing valve. Buffer pistons provided at the other ends of both cylinders are biased so that they move the working pistons to a predetermined adjustable starting position.