Abstract: In a concrete finishing machine having a plurality of vibrators to be at least partially submerged in concrete or other semi-fluid viscous material for vibration thereof, a monitor is provided for displaying and/or recording operational parameters of the plurality of vibrators. The monitor includes a display, responsive to signals generated by sensors operatively associated with the plurality of vibrators, for providing a visual indication of operating parameters for the plurality of vibrators, and a recording device receiving the signals generated by sensors operatively associated with the plurality of vibrators and recording the operating parameters for the plurality of vibrators.

Abstract: In a vibrator intending to be at least partially submerged in concrete or semi-fluid or viscous material for vibration thereof, the vibrator having a housing open at one end and enclosing a rotating eccentric weight assembly, and a motor attached to the housing open end driving the rotating eccentric weight, a vibration speed sensor includes a magnetic pick-up disposed in a port in an end wall of the motor and adjacent an end of a gear/gear shaft of magnetic material in said motor, wherein the gear/gear shaft has a discontinuity adjacent the magnetic pick-up, whereby rotation of the gear/gear shaft is sensed by the magnetic pick-up. The motor includes hydraulic inlet and outlet ports in the motor end wall with the magnetic pickup port disposed adjacent thereto. An output cable is connected to the magnetic pick-up and extends in parallel with hydraulic hoses attached to the hydraulic inlet and outlet ports.