Patent ID: 9683637
Date: 2017-06-20
CPC Classifications: F02B,F16H

Claim:
1. A tensioner for a passive tensioner system tensioning a span of chain or a belt comprising: a housing having a first axially extending bore with a first fluid input and a second axially extending bore with a second fluid input; a first piston slidably received by the first axially extending bore, the first piston comprising a body having a first end and a second end; a first pressure chamber for biasing the first piston outwards from the housing, defined between the first piston and the first axially extending bore and in fluid communication with the first fluid input; a second piston slidably received within the second axially extending bore, the second piston comprising a body having a first end and a second end; a third piston slidably received within the second axially extending bore, the third piston comprising a body having a first end with a top surface and a second end; a second piston spring received in the second axially extending bore, the second piston spring having a first end in contact with the second piston and a second end in contact with the top surface of the third piston; a third piston spring received in the second axially extending bore, the third piston spring having a first end in contact with the third piston and a second end in contact with the second axially extending bore; a second pressure chamber defined between the third piston and the second axially extending bore, in fluid communication with the second fluid input; and a check valve between the second pressure chamber and the second fluid input; wherein when dynamic load from the chain or belt moves the first piston and the second piston inwards and outwards from the housing, fluid from the second fluid input is drawn into the second pressure chamber through the check valve, creating a fluid pressure in the second pressure chamber, causing the third piston to move outwards from the housing and exert an outward force on the second piston through the second piston spring, opposing an inward force of the dynamic load.