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US 6,685,587 B2Granted
Hydraulic chain tensioner with no-return device for the piston
AssigneeBorgWarner Inc.
InventorsFrancesco Rossato, Daniele Redaelli, Germinal F. Capucci
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AssigneeBorgWarner Inc.
InventorsFrancesco Rossato, Daniele Redaelli, Germinal F. Capucci
Estimating the term…
A cartridge type hydraulic tensioner for a chain or belt is described comprising a cylinder (11) with an inner bore (13) and a hollow piston (12) sliding in the cylinder and biased outward by an elastic elements and by pressurized fluid fed into said bore (13), at least one rack (20) being formed on the skirt of the piston (12) and engaged by a toothed pad (21) passing through a corresponding aperture (22) formed in the wall of the cylinder and biased against the rack by an annular spring (25) housed in an annular seat (24) formed in the skirt of the cylinder (11) without protruding from the bulk of the cylinder.
A cartridge tensioner for chain or belt transmission systems, comprising a body or cylinder (11) with an inner bore (13) and a hollow piston (12) axially slidable in the cylinder under the action of elastic biasing means (16) acting between said cylinder and said piston and of pressurized fluid fed into said bore (13), so that an upper end (17) of the piston acts on a movable shoe (5) to tension a chain or belt (1) and also comprising a device able to prevent uncontrolled return of said piston (12) into the cylinder, characterized in that on a skirt of the piston (12) at least one longitudinal rack (20) is provided, engageable by a toothed pad (21) extending through an aperture (22) formed in a wall of the cylinder and biased by an elastic means (25) housed in a seat (26) of the cylinder (11), without protruding from the outer profile of said cylinder, a longitudinal extent of said toothed pad (21) being smaller than a corresponding longitudinal extent of said aperture (22) formed in the wall of the cylinder (11) so that said pad has a certain degree of longitudinal sliding and thus allowing controlled re-entry of the piston (12) into the cylinder (11) said toothed pad (21) further having an elongated base (23) housed in a corresponding seat (24) in the wall of the cylinder (11) for guided sliding of said pad (21).
A chain drive, comprising:
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
Means for varying tension of belts, ropes or chains: with means for impeding reverse motion
With means for impeding reverse motion: ratchets
With means for impeding reverse motion: check valves
Control or adjustment of actuators: disabling during transport
Term ended 11 Sep 2021 (estimated)
The present application claims priority to, and benefit under 35 USC §119(a)-(d) of, the European Patent Application No. 00830616.9, filed Sep. 13, 2000.
1. Field of the Invention
The invention refers to devices for tensioning drive transmission means, such as chains. In particular reference will be made to chain transmission means on vehicles.
FIG. 1 is a sectional view of a prior art tensioning device, of a type for mounting inside an engine block, as previously described;
FIG. 2 is a diagrammatic illustration of a chain drive, provided with a tensioning device of the cartridge type.
FIG. 3 is a diagrammatic axial sectional view of a cartridge type tensioner according to the invention, before fitting.
FIG. 2 diagrammatically shows a chain drive to which the tensioner according to the invention can be applied.
In particular a driving wheel 2 and a driven wheel 3 are shown, on which a chain 1 is wound, a taut branch or run of which (the lower one in the figure) is guided by a suitable guide 4, a slack branch or run (the upper one in the figure) is tensioned by means of a shoe 5, swingable around a pin 6, and pushed against the corresponding run of the chain by a tensioning device, indicated as a whole by reference numeral 10, which in this case is a cartridge tensioner, of the type previously mentioned, that is screwed into the engine block or into the head.
Said tensioner 10 will now be described in greater detail with reference to FIGS. 3 to 7.