Patent ID: 6658739
Filing Date: 2003-12-09
Classification: B23D

Abstract:
A pipe cutter comprising:a main body including an internal elongate slot, a top recess, and two side guides on a tunnel between the recess and the slot; a fastening mechanism including two pivot members on both sides of the recess, each pivot member having a lower end pivotably connected to the main body, two bifurcated links each having a top end pivotably connected to the pivot member, and two rollers each rotatably connected to a top end of the pivot member; a cutting mechanism including a sliding block defined by the guides, a top rotary blade, and a first spring having a top end urged against the bottom of the sliding block; and a transmission mechanism including a sliding toothed member fitted in the main body, a pivot axis slidable along the length of the slot and pivotably connected the links and the top of the sliding toothed member together, an outer knob having a pinion and an outer ratchet wheel both being corotated with the knob in a predetermined direction, a second spring biased between the bottom of the sliding toothed member and the bottom of the main body, a spring biased pawl engageable with the ratchet wheel, a first gear rotatably connected to the main body and meshed with both the teeth at one side of the sliding toothed member and the pinion, a second gear rotatably connected to the main body and meshed with both the teeth at the other side of the sliding toothed member and the first gear, and a spring biased push button in a recessed portion of the main body opposite to the knob, the push button being connected to the pinion; wherein in a fastening and cutting operation of a pipe, place the pipe into the recess on the top of the blade, rotate the knob clockwise to cause the pinion to rotate the meshed first and the second gears, in response the sliding toothed member slides down to compress the second spring due to gear engagements of left and right teeth thereof with the first and the second gears respectively, the links move down to swing the pivot members toward the recess to cause the rollers to contact the pipe, and a continuous rotation of the knob causes the rollers to press down the pipe toward the blade for being cut as the first spring is compressed; and in a returning process, push the push button to cause the knob to project above the outer surface of the main body for disengaging the ratchet wheel and the pinion from the pawl and the first gear respectively, in response, the sliding toothed member moves upward immediately as the expansion of the second spring, and the links move upward to cause the pivot members to swing outward away from each other until being stopped in their original unused positions.