PURPOSE: To protect machine parts and prevent the rupture of a pumping tube, by building a speed changer and a speed reducer in a housing so that the speed changer and the speed reducer can be operated by external manipulation.

CONSTITUTION: When an input shaft 20 is rotated, an intermediate transmission member 24 is rotated in the same direction through a planet gear 25 to cause the speed-reduced rotation of a housing 15 in the opposite direction through a final gear 5 so that pumping action is effected by squeeze rollers 19. When the torque of the housing 15 has exceeded a prescribed value due to the biting-in of an extraneous substance or other causes, an arm 6 swings in a direction Z against the force of a spring 9 to stop the transmission of torque to the housing and operate a limit switch 13 to stop a prime mover.