Abstract: A riding-type surface working machine includes a pair of rotors each of which carries a plurality of trowels or surface working members. Each rotor includes a transmission unit and power from the engine is transmitted through each transmission unit to rotate the individual rotors. To provide directional movement for the machine, the upper end of each rotor includes a shaft that is connected to the respective transmission unit. The shaft is mounted for universal tilting movement with respect to the frame of the machine. An eccentric is mounted on each rotor shaft and is rotatable in a fixed sleeve. Each eccentric is connected through a chain drive to a vertical control stick and the control sticks for the respective rotors are mounted concentrically on the machine. Through manual operation of the control sticks the eccentrics can be individually rotated to thereby tilt the rotors to cause directional movement of the machine.

Abstract: A vibratory compactor having forward and reverse movement. The compactor comprises a bottom plate and a pair of standard, single shaft, vibration generating units are mounted in side-by-side relation on the bottom plate and each unit includes an eccentric shaft. The eccentric weight of one of the shafts can be varied in angular position with respect to the weight of the other shaft to provide both forward and reverse movement for the compactor. To adjust the angular position of one of the eccentric shafts, an axially slidable collar is splined to the eccentric shaft and a drive lug on the collar can be selectively engaged with a drive element on a drive gear or with a drive element on a ring which is fixed to the gear and spaced axially therefrom. The drive elements on the gear and the ring are displaced 180.degree.. By moving the collar axially through a manual control, the drive lug will be disengaged with the drive element on the gear and will be engaged with the drive element on the ring.

Abstract: A concrete finisher of the type having driven paddles surrounded by a peripheral guard ring is made with one or more relieved guard ring sections, each preferably having a flattened outer edge, so that the finisher can be used to finish concrete surfaces adjacent to a wall or other obstruction. In some embodiments the relieved guard ring wall guide section is fixed. In other embodiments it is retractable.