Patent ID: 6227760
Filing Date: 2001-05-08
Classification: B06B,E01C,Y10T

Abstract:
A vibrating plate compactor comprising:first and second eccentric rotors on first and second parallel drive shafts which are operatively coupled together;a piston rod slidably inserted into the first drive shaft which supports the first eccentric rotor;a vibration generator having a hydraulic cylinder to switch rotation of said first and second eccentric rotors in one of a forward and backward direction, the hydraulic cylinder axially moving the piston rod by an outside force to resist a mechanical return force generated by rotation of said first and eccentric rotors; anda travel control device for imparting the outside force to the hydraulic cylinder, the travel control device including a piston which receives the mechanical return force from said vibration generator at one end and pressure oil from an outside hydraulic pump at an other end, a push rod operatively coupled to the piston for switching a travel direction, and a spool for a servo valve to supply the pressure oil from said hydraulic pump to the side of the piston opposite the side receiving the mechanical return force wherein the spool has first and second ends and is positioned at a central portion of the travel control device, both ends of said spool being supported by springs disposed between the push rod provided at one end of the travel control device and the piston at the other end of the travel control device, and a first passage on a vibration generator side of the travel control device to supply the mechanical return force from said vibration generator to a space between the spool and the piston, and a second passage on a pump side of the travel control device to supply the pressure oil from a hydraulic pump to oppose the mechanical return force between the spool and the outside of the piston.