Patent ID: 6170310
Filing Date: 2001-01-09
Classification: B21D

Abstract:
A transmission shaft of a movable arm of a pipe bended, comprising:(a) a longitudinally extended main shaft having an upper end fixedly connected to said movable arm of said pipe bender, said main shaft having:(i) a longitudinally directed cavity formed therein;(ii) a plurality of evenly spaced longitudinally directed pinholes each receiving a pin therein, said plurality of pin holes being in open communication with said cavity;(iii) a plurality of openings formed through a wall of said main shaft and in open communication with said cavity, each of said openings being located in correspondence with a respective one of said pinholes;(iv) a plurality of planet gears received in said cavity of said main shaft, each being pivoted on a corresponding one of said pins, and a portion thereof extending through a corresponding one of said openings; and,(v) a gear ring disposed in said cavity of said main shaft and having a through hole formed centrally therein, said gear ring having teeth formed on an external surface thereof engaged with said plurality of planet gears for rotation of said planet gears responsive to rotation of said gear ring, said through hole having an internal surface with teeth formed thereon;(b) a sun gear ring fixed to a connecting part of a fixed arm of said pipe bender, said sun gear ring being located around, and engaging said portion of said planet gears extending through said openings; and,(c) a central gear shaft having an upper end gear portion passed into said cavity of said main shaft, said upper end gear portion being received in said through hole of said gear ring and engaging said teeth on said internal surface for passing on power to said planet gears through said gear ring, whereby the movable arm is rotated by rotation of the main shaft, the main shaft being rotated by displacement of the planet gears relative to the sun gear ring when the central gear shaft is turned because the sun gear ring engaging the planet gears is fixed to the fixed arm and the upper end gear portion of the central gear shaft engages the gear ring to rotate therewith to rotate the planet gears.