Series arrangement of hydraulic chain tensioner and ratchet

A tensioner (10) for an endless loop power transmission member comprising:

• a piston (12) operably engageable with an endless loop power transmission member;
• a cylinder (14) guiding the piston (12) for sliding coaxial movement in a direction of the endless loop power transmission member and defining an oil reservoir (26) for receiving hydraulic fluid;
• a bearing (28) having bearing balls (30) located in a counter bore (32) coaxial with cylinder bore (34), the counter bore (32) having a steep taper (36) on which the bearing balls (30) ride, such that as the cylinder (14) moves in an extending direction, the bearing balls (30) move out of the counter bore (32) allowing free extending movement of the cylinder (14), and such that as the cylinder (14) moves in a retracting direction, the bearing balls (30) are driven down into the steep taper (36) preventing the cylinder (14) from retracting;
• a circular clip (38) retained within a groove in an inside diameter (ID) of the piston (12), wherein the cylinder (14) has a groove (40) of given width on the cylinder (14) in which the circular clip (38) rides, the given width corresponding to an allowable backlash for the tensioner (10);
• an end wall of the groove (40) coming into contact with the circular clip (38) during extending movement, such that the circular clip (38) pulls the cylinder (14) with the circular clip (38) resulting in endless loop power transmission member slack take-up;
• a bias spring (42) acting between the bearing (28) and piston (12), the bias spring (42) serving to bias the piston (12) out of the cylinder (14) when the circular clip (38) contacts the end wall of the groove (40) resulting in extension and endless loop power transmission member take-up;
• and
• a check valve (16) located between the piston (12) and cylinder (14).