| 摘要 |
A stepped set groove having shallow and deep portions is formed in the inner periphery of a cylinder chamber formed in a housing of a chain tensioner near its open end. A radially and elastically deformable set ring having circumferentially separated ends is received in the set groove in a radially compressed state. The set ring has at the respective ends thereof a pair of grip portions which are received in a cutout formed in housing at its front end. By engaging the set ring in an engaging groove formed in the outer periphery of the plunger near its front end and the shallow portion, it is possible to keep the plunger pushed into the cylinder chamber. In this state, the chain tensioner is mounted in position. One of the grip portions is brought into abutment with one of the circumferentially opposed end walls of the cutout to prevent the plunger from rotating about its axis in such a direction that the axial gap between an internal thread of the plunger and an external thread of a screw rod inserted in the plunger disappears. Thus, it is possible to keep the axial gap larger than the axial distance by which the plunger has to be moved to move the set ring from the shallow portion into the deep portion. This makes it possible to disengage the set ring from the engaging groove by pushing the plunger into the cylinder chamber.
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