Checker-arm chain lubricating apparatus

A checker-arm chain lubricating apparatus for lubricating a chain running along a travel path, comprising:

• a main body case fixedly placed in a vicinity of the travel path of the chain;
• a cam shaft swingably supported on said main body case, wherein said cam shaft has an axis intersecting a direction in which the chain travels, said cam shaft having a protruding portion protruding outside said main body case;
• a checker arm fixed at a base end thereof on said protruding portion, wherein a tip end of said checker arm is engaged with the chain as the chain travels along the travel path so that said checker arm is oscillated about an axis of said cam shaft between an engagement start position and a disengagement position;
• a return spring for returning said checker arm to said engagement start position when said tip end of said checker arm is disengaged from the chain at said disengagement position;
• a plunger activating cam fixed to said cam shaft, wherein said plunger activating cam has a planar cam face which is normally at substantially right angles to said axis of said cam shaft;
• a cam follower slidably supported on said main body case in a direction at substantially right angles to said axis of said cam shaft and abutted against said cam face;
• a pump unit arranged on said main body case and having a plunger sliding integrally with said cam follower in order to discharge a lubricant toward the chain from a lubricating nozzle communicating with a discharge port when said plunger moves in a forward direction and to take in said lubricant from an oil tank communicating with an intake port when said plunger moves in a backward direction;
• and
• wherein when said checker arm is angularly moved from said engagement start position toward said disengagement position, said plunder activating cam turns to cause said cam face to move said cam follower and said plunger in said forward direction, and when said checker arm is returned from said disengagement position to said engagement start position by said return spring, said plunder activating cam turns to cause said cam face to move said cam follower and said plunder in said backward direction.