Mechanical chain tensioner with ratcheting device

A blade tensioner system for a chain, the system including a blade tensioner imparting tension to the chain that drivingly connects a driven shaft to a driving shaft in an engine, the blade tensioner comprising:

• a blade shoe having an arcuately curved chain sliding face, a proximal end portion pivotally attached to a bracket and a distal end portion;
• a sliding surface having a first side for slidably receiving the distal end portion of the blade shoe and a second side;
• a ratchet rod having a first end pivotally attached to the distal end of the blade shoe and a second end with a length having a plurality of teeth with a length;
• and
• a spring clip for receiving the second end of the ratchet rod and being slidable along the second side of the sliding surface, the spring clip having:
• an edge for abutting the plurality of teeth of the ratchet rod and pressing against the ratchet rod opposite the length of the rod having the plurality of teeth, to bias the ratchet rod into engagement with the edge of the spring clip and a tab for engagement with a corresponding indentation on the second side of the sliding surface;
• wherein when slack of the chain increases, the distal end of the blade shoe pivots away from the chain and slides on the first side of the sliding surface, and the spring clip slides on the second side of the sliding surface a distance limited by the engagement of the tab of the spring clip with the corresponding indentation on the second side of the sliding surface, such that the edge of the spring clip abuts the plurality of teeth of the ratchet rod, allowing movement of the distal end of the blade shoe towards the proximal end of the blade shoe and preventing movement in an opposite direction;
• wherein maximum backlash of the tensioner is a sum of a distance between the edge of the spring clip and a bottom of the first sliding surface and the length of the teeth of the ratchet rod.