US 4,728,317 AGranted

Belt tensioner, part therefor and methods of making the same

AssigneeDayco Products, Inc.

InventorsVernon H. Martz, Leslie B. Wilson

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Abstract

A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a piston and cylinder unit having a cylinder member and a piston member disposed in the cylinder member, the cylinder member having a tapering chamber defining a substantially straight line tapering internal peripheral side wall of the cylinder member that extends substantially from one end thereof and to the other end thereof and carrying a rolling diaphragm for rolling against the tapering side wall throughout substantially the entire normal tensioning range of movement of the belt engaging unit of the tensioner relative to the support unit of the tensioner whereby the relative movement between the members changes the effective area of the rolling diaphragm and, thus, the tensioning force on the belt engaging unit in a substantially linear manner throughout the normal tensioning range of movement of the belt engaging unit relative to the support unit, the diaphragm having its outer periphery secured to the cylinder member intermediate the opposed ends thereof whereby the tapering chamber extends from the opposed sides of the diaphragm.

Claims30

Dependent claims

In a tensioner for a power transmission belt that is adapted to be operated in an endless path, said tensioner comprising a support means for being fixed relative to said belt, a belt engaging means carried by said support means and being movable relative thereto, force producing means operatively associated with said support means and said belt engaging means for urging said belt engaging means relative to said support means in a belt tensioning direction and against said belt with a force to tension said belt, and a fluid operated transmitting means operatively associated with said force producing means and said belt engaging means for translating forces therebetween whereby said force producing means is adapted to be disposed remote from said belt engaging means, said fluid operated transmitting means including a piston and cylinder means having a cylinder member and a piston member disposed in said cylinder member, one of said members being adapted to be fixed to define part of said support means with the other of said members being movable relative thereto and being operatively associated with said belt engaging means, the improvement wherein said cylinder member has opposed ends and a tapering chamber defining a substantially straight line tapering internal peripheral side wall of said cylinder member that extends substantially completely between said opposed ends, and a rolling diaphragm carried by said cylinder member for rolling against said tapering side wall throughout substantially the entire normal tensioning range of movement of said belt engaging means relative to said support means, said diaphragm having opposed sides and an outer peripheral means secured to said cylinder member intermediate said opposed ends thereof whereby said tapering chamber extends from said opposed sides of said diaphragm, said piston member being operatively associated with said rolling diaphragm whereby said relative movement changes the effective area of said rolling diaphragm and, thus, the tensioning force on said belt engaging means in a substantially linear manner throughout substantially the normal tensioning range of movement of said belt engaging means relative to said support means.

In a method of making a tensioner for a power transmission belt that is adapted to be operated in an endless path, said method comprising the steps of providing a support means for being fixed relative to said belt, providing a belt engaging means carried by said support means and being movable relative thereto, operatively associating force producing means with said support means and said belt engaging means for urging said belt engaging means relative to said support means in a belt tensioning direction and against said belt with a force to tension said belt, operatively associating a fluid operated transmitting means with said force producing means and said belt engaging means for translating forces therebetween whereby said force producing means is adapted to be disposed remote from said belt engaging means, forming said fluid operated transmitting means to include a piston and cylinder means having a cylinder member and a piston member disposed in said cylinder member, and forming one of said members to be adapted to be fixed to define part of said support means with the other of said members being movable relative thereto and being operatively associated with said belt engaging means, the improvement comprising the steps of forming said cylinder member to have opposed ends and a tapering chamber defining a substantially straight line tapering internal peripheral side wall of said cylinder member that extends substantially completely between said opposed ends, securing an outer peripheral means of a rolling diaphragm to said cylinder member intermediate said opposed ends thereof for rolling against said tapering side wall throughout substantially the entire normal tensioning range of movement of said belt engaging means relative to said support means whereby said tapering chamber extends from the opposed sides of said diaphragm, and operatively associating said piston member with said rolling diaphragm whereby said relative movement changes the effective area of said rolling diaphragm and, thus, the tensioning force on said belt engaging means in substantially a linear manner throughout substantially the entire normal tensioning range of movement of said belt engaging means relative to said support means.

Dependencies are inferred from the claim text.