GB1472568A - Pneumatic vibrator - Google Patents

Abstract

1472568 Vibrators OSBORN MFG CORP 16 July 1974 [24 Aug 1973] 31454/74 Heading F2X A pneumatic vibrator includes a bore 14 in which a plunger B is reciprocatingly positioned for movement between the position shown (or striking position) and an exhaust position, an air inlet port 26, 28 and an air exhaust port 72 communicating with the bore 14 on opposite sides of the plunger B, and exhaust passage means through the plunger B for exhausting air from the inlet port 26, 28 to the exhaust port 72 in the exhaust position of the plunger B. End caps C, D are screwthreaded into the ends of the vibrator body 12, inlet port 26, 28 extending through the end cap C and exhaust port 72 through the end cap D. A cylindrical striker insert E made of a material having low sound transmitting characteristics, e.g. natural or synthetic rubber, is tightly fitted within a cylindrical recess 30 formed in end cap C. Compressed air from the inlet port 26, 28 passes through an axial hole 34 and at least one radially extending notch formed in the insert E and enters an annular space 44 surrounding the frusto-conical striker end portion of the plunger B. The compressed air forces the plunger B away from the insert E toward its exhaust position against the biasing action of a coil spring 64 housed within an axial bore 58 of the plunger B. As the plunger B moves to the right, communication is established between the annular space 44 and the exhaust port 72 via a circumferential groove 50 formed in the bore 14 and radial bores 60, an axial bore 102 and the larger diameter axial bore 58 of the plunger B. The exhausting action occurs before the plunger end makes contact with the end surface 70 of end cap D. An enlarged outwardly opening flared recess 74 is formed in end cap D coaxial with exhaust port 72, a noise muffler 76 of metal wool or multi-layer metal mesh being held within this recess by means of a fine screen 78, the muffler and screen together preventing foreign particles from entering the bore 14 through the exhaust port 72. End cap D has an enlarged cylindrical recess 104 extending inward from end surface 70 for receiving the end of spring 64. The large cavity defined by the bores 58, 104 and a portion of bore 14 allows a substantial quantity of air to accumulate under slight pressure for aiding spring 64 in shifting plunger B back to its striking position. The repeated striking of insert E by plunger B rapidly builds up heat as a result of internal friction, which heat is however dissipated by the continuous flow of cool compressed air in contact with insert E.