GB190800449A - Improvements in and relating to Hammers and other Machines and Air-compressors for Driving them. - Google Patents

Abstract

449. Maasey, H. F. Jan. 8. Fluid-pressure hammers. -Relates to hammers and other machines driven by compressed air, of the type in which each movement of the tool piston is effected by the movement of a distributing- valve, and the exhaust is connected to the inlet of a continuously-moving compressor. According to the invention, the output of the compressor is made to correspond accurately with the, variable requirements of the tool by limiting the air on which the compressor can operate to that discharged from the tool, so that, if the tool is stopped or worked slowly, a vacuum or a reduction of pressure occurs in the inlet pipe to the compressor, and the compressor is therefore more or less unloaded. The single-acting compressor a is connected to the distributing-valve chamber m of a double-acting hammer cylinder b by a delivery pasage r and a return or intake passage u so as to form a closed-circuit apparatus in which the compressor is more or less unloaded, when the hammer is stopped or worked slowly. A relief valve s is provided in the delivery passage and, optionally, a reservoir t. To enable the desired pressure to be created in the system at starting, air is admitted by way of a pipe v and valve w, or a valve operated by hand, to the intake passage; air for making up leakage losses is also admitted past the valve w. Where a pressure above atmospheric is maintained in the system, this air may be supplied by a feed'-pump. To prevent this supply of air from being prejudicial to the unloading of the compressor, the inlet v is adapted to be closed when a predetermined pressure is attained in the delivery passage r; thus the inlet may be closed by a valve x connected with a spring-pressed piston y subject to the predetermined pressure Any form of compressor may be employed as, for example, a reversed turbine, a rotary pump, or a multi-cylinder pump, and one compressor may supply air to two or more hammers or other tools.