Stepwise powerful suction device

A stepwise powerful suction device comprising:

• at least one suction holder, a suction element associated with each suction holder, a resilient element associated with each suction holder, a support frame, and a rotary knob associated with each suction holder;
• wherein the support frame is integrally formed with the suction holder and a portion of the suction holder forms a handle;
• wherein the suction holder forms a central bore and a multi-step stepwise recess, the central bore having an inside surface in which at least one slot is formed, the multi-step stepwise recess comprising at least two sets of a first deepest step, a second next deepest step, a third next shallowest step, and a fourth shallowest step that are sequentially arranged and respectively corresponding to two sets of first, second, third, and fourth marks formed on an outside surface of the suction holder;
• wherein the suction element comprises an upright post to which a guide pegs is mounted for being slidably received in the slot of the suction holder, the upright post having a top end forming an inner-threaded hole;
• wherein the rotary knob comprising a rotatable handgrip, a spacer ring, a bolt, and a cap, the handgrip having an under surface that forms a multi-step stepwise projection corresponding to the multi-step stepwise recess of the suction holder, the multi-step stepwise projection comprising at least two sets of a fourth highest step, a third next highest step, a second next lowest step, and a first lowest step that are sequentially arranged and respectively corresponding to the two sets of first, second, third, and fourth marks formed on the outside surface of the suction holder, a stop being formed on the outside surface of the suction holder at a location adjacent to one of the fourth shallowest steps to correspond to a raised portion formed on the handgrip, whereby when the handgrip is rotated to an extreme angular position, the raised portion engages the stop to prevent further rotation of the handgrip;
• wherein safety locking means is provided between the multi-step stepwise recess and the multi-step stepwise projection, the safety locking means comprising a groove formed in each of the steps of the multi-step stepwise recess and a corresponding rib formed on each of the steps of the multi-step stepwise projection, whereby when the multi-step stepwise projection is rotated to reach each of a plurality predetermined engaging positions, the rib and the groove engage each other to lock the multi-step stepwise projection with respect to the multi-step stepwise recess;
• wherein the upright post of the suction element extends through the resilient element and the central bore of the suction holder with the multi-step stepwise projection of the handgrip stacked on and mating the multi-step stepwise recess of the suction holder, the handgrip forming a stepped bore that receives the spacer ring therein, the upright post of the suction element being fit through the spacer ring, the bolt extending through the spacer ring and engaging the inner-threaded hole of the upright post of the suction element, the cap then closing the stepped bore of the handgrip, whereby when the handgrip is rotated to cause relative rotation between the multi-step stepwise projection and the multi-step stepwise recess, the upright post of the suction element is lifted by different distances to induce different and stepwise suction forces in the suction element.