GB1355591A - Rotating pneumatic vibrator - Google Patents

Abstract

1355591 Vibrators T S WADENSTEN 26 June 1972 29760/72 Heading F2X A rotary pneumatic vibrator, of the type in which vibrations are generated by the rotation of an off-centre member within the vibrator, comprises a cylindrical housing 11 within which is mounted a central fixed shaft 19 having a longitudinally extending radially movable vane 29 which engages the inner face of a circular rotor 38 mounted between the housing 11 and the shaft 19. The vane is pneumatically driven against the rotor 38 and also serves as a valve controlling the air flow into a high pressure space 39 formed between the shaft 19 and the rotor 38. As air pressure is applied to the vane 29 and to the space 39, the rotor 38 is caused to move about the shaft 19 with the air escaping through exhaust bores 37 on the far side of the shaft 19 to permit the rotor 38 to return to its starting position. The movement of the rotor 38 creates an unbalanced condition and causes vibrations to be produced. The shaft 19 has a radial slot 28 extending longitudinally throughout its length and housing the vane 29. An air supply pipe communicates with one end of the slot 28 and, in operation, compressed air enters the slot 28 and raises the vane 29 into contact with the rotor 38, forcing it into contact with the shaft 19 immediately below the vane 29, thus assuming the position shown in Fig. 4. Slots 36 formed in the vane 29 provide communication between the slot 28 and the space 39. A second, low pressure space 40 is formed on the opposite side of the shaft 19 and the bores 37 provide communication between this space and a longitudinally extending exhaust bore 33 formed in the shaft 19. Air flowing through the slots 36 forces the rotor 38 to the left which in turn depresses the vane 29, a stage being reached (Fig. 6, not shown) in which the slots 36 are shut off by the walls of the slot 28 and the air in the enlarged space 39 escapes through the bores 37. As soon as the slots 36 are closed, the air pressure begins to build up behind the vane 29 until it is forced upwardly into the Fig. 4 position and a fresh cycle commences. The motion of the rotor 38 is a combination of rotation and impact as it strikes the shaft 19, or both the shaft 19 and the housing 11 if it is of sufficient external diameter.