Chain drive tensioner spring force control mechanism
First Claim
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1. A tensioner for a passive tensioner system for tensioning a chain span or a belt, comprising:
- a housing having a cylindrical bore;
an external piston comprising a body having an open end and a closed end, a bottom surface at the open end, and a hollow interior having an inner diameter;
an internal piston comprising a body having a first end and a second end;
the external piston and the internal piston being coaxially arranged within the cylindrical bore of the housing, such that the interior piston is received within the hollow interior of the external piston;
an external piston spring received within the hollow interior of the external piston, for biasing the external piston outwards from the housing, the external piston spring having a first end contacting an inner surface of the closed end of the external piston and a second end contacting the first end of the internal piston;
an internal piston spring received within the cylindrical bore of the housing for biasing the internal piston outwards from the housing, the internal piston spring having a first end in contact with the second end of the internal piston and a second end;
a first hydraulic chamber formed by the cylindrical bore of the housing and the bottom surface of the external piston, having a first fluid input comprising a first check valve; and
a second hydraulic chamber formed by the cylindrical bore of the housing and the second end of the internal piston with a second fluid input comprising a second check valve, such that an inward force acting to push the external piston into the housing creates a fluid pressure in the second hydraulic chamber, causing the internal piston to exert an outward force on the external piston through the external piston spring, opposing the inward force.
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Accused Products
Abstract
A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.
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Citations
10 Claims
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1. A tensioner for a passive tensioner system for tensioning a chain span or a belt, comprising:
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a housing having a cylindrical bore; an external piston comprising a body having an open end and a closed end, a bottom surface at the open end, and a hollow interior having an inner diameter; an internal piston comprising a body having a first end and a second end; the external piston and the internal piston being coaxially arranged within the cylindrical bore of the housing, such that the interior piston is received within the hollow interior of the external piston; an external piston spring received within the hollow interior of the external piston, for biasing the external piston outwards from the housing, the external piston spring having a first end contacting an inner surface of the closed end of the external piston and a second end contacting the first end of the internal piston; an internal piston spring received within the cylindrical bore of the housing for biasing the internal piston outwards from the housing, the internal piston spring having a first end in contact with the second end of the internal piston and a second end; a first hydraulic chamber formed by the cylindrical bore of the housing and the bottom surface of the external piston, having a first fluid input comprising a first check valve; and a second hydraulic chamber formed by the cylindrical bore of the housing and the second end of the internal piston with a second fluid input comprising a second check valve, such that an inward force acting to push the external piston into the housing creates a fluid pressure in the second hydraulic chamber, causing the internal piston to exert an outward force on the external piston through the external piston spring, opposing the inward force. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification