GB1354567A - Vibrators - Google Patents

Abstract

1354567 Vibrators DYNAPAC MASKIN AB 24 June 1971 [23 June 1970] 29622/71 Heading F2X A vibrator driven by a pressurized fluid medium, e.g. compressed air, flowing between a hollow cylinder 2 and the bore 19 of a housing 1 in which the cylinder is mounted for relative rotation, comprises five longitudinal spiral grooves 3a equispaced circumferentially about the bore 19 and four longitudinal spiral lobes 5 equispaced circumferentially about the cylinder 2, the dimensions of the cylinder 2, lobes 5, bore 19 and grooves 3a being such that relative rotation may be effected between the cylinder 2 and the bore 19 whereupon successive lobes 5 engage in successive grooves 3a, the spiral grooves 3a and spiral lobes 5 forming part of the flow path for the compressed air. The compressed air enters the vibrator through a hose 10 and hose coupling 9, and flows down a central passage 8 in the cylinder 2, returning along the space between the cylinder 2 and the bore 19 of the housing 1. The bore 19 is defined by a cylindrical insert in the housing 1 comprising at least cylindrical bushings 4, 4<SP>1</SP>, 411, axially aligned and having the longitudinal grooves 3a formed in their inner surfaces, located between two plain bore bushings 7, 7<SP>1</SP>. The end portions 6, 6<SP>1</SP>, of the hollow cylinder 2 are plain and engageable in rolling contact with the plain bore bushings 7, 7<SP>1</SP>. The diameter of a circle contacting the outer tips of the lobes 5 is substantially equal to, but not greater than, the diameter of the bore into which the spiral grooves 3a are formed plus the depth of one longitudinal groove 3a. The spiral grooves 3a and the spiral lobes 5 comprise multi-start screw threads. The returning compressed air flows between the grooves 3a and the lobes 5 and torque is thus applied to the cylinder 2 to produce a vibrationgenerating rolling motion of the cylinder 2. Owing to the number of longitudinal grooves 3a exceeding the number of lobes 5 by one, a space is created opposite the lobe engaged in a groove having the shape of a spiral loop around the cylinder 2 and this space will move circumferentially as a result of the rolling movement of the rotor.