Dust-collecting devices and cutting devices with the dust-collecting devices

A circular saw comprising:

• a saw unit comprising a rotary circular saw blade and a cover for covering the saw blade, the saw unit being mounted for pivotal movement;
• and
• a dust-collecting device connected to the saw unit and comprising a first dust-collector, a cyclone unit, and a second dust-collector, assembled to each other, the dust-collecting device being mounted for pivotal movement with the saw unit;
• wherein the first dust-collector defines a first dust-collecting chamber and is connected to the cover, so that cutting chips produced by the saw blade during a cutting operation are fed into the first dust-collecting chamber together with a flow of a carrier air and at least a portion of the cutting chips are collected within the first dust-collecting chamber by at least a force of gravity;
• wherein the cyclone unit is arranged and constructed to receive remaining cutting chips carried by the air, which were not collected within the first dust-collecting chamber;
• wherein the cyclone unit comprises a cyclone body, a remaining cutting chip discharge pipe, and an air discharge pipe;
• wherein the cyclone body has an inner wall and is arranged and constructed to cause circulation of the remaining cutting chips together with the carrier air along a circumference of the inner wall, while separated remaining cutting chips drop downward by at least the force of gravity;
• wherein after separation the carrier air is discharged from the cyclone body via the air discharge pipe;
• wherein the separated remaining cutting chips are discharged from the cyclone body via the cutting chip discharge pipe;
• and
• wherein the first dust-collecting chamber comprises:
• an inlet;
• a terminal end opposing to the inlet in a direction of flow of the cutting chips entering the inlet, so that the cutting chips collide with the terminal end;
• and
• an outlet disposed on a lateral side of the collecting chamber and positioned to be spaced apart from the terminal end by a predetermined distance in a direction toward the inlet, so that a space is defined between the outlet and the terminal end in order to prevent the cutting chips from entering the outlet due to rebounding after collision with the terminal end.