| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To speed up retraction of a plunger when tension of a wrapping transmission body is excessive, and thereby to alleviate a load on the wrapping transmitter, and noise, resulting from excessive tension, in a ratchet type tensioner capable of regulating the retraction of the plunger. <P>SOLUTION: In a ratchet mechanism R of the ratchet type tensioner, when a second reaction force F2 acts on a plunger 120 while tension of a wrapping transmitter is excessive, a ratchet 150 slides in a disengaging direction and ratchet teeth 151 disengage from rack teeth 122, thereby allowing the plunger 120 to retract. An outer peripheral surface 153 of the ratchet 150 has second sliding contact surfaces 156, 157 included that are curved surfaces coming in contact with an inner peripheral surface 115 when the ratchet 150 pressed in a retraction direction by the plunger 120 with the second reaction force F2 acting thereon is inclined. The ratchet 150 slides in a disengaging direction while coming in line contact with the inner peripheral surface 115 on each of the second sliding contact surfaces 156, 157. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
