US 5,209,703 AGranted

Drive pulley

AssigneeBombardier Inc.

InventorsBrian H. Mastine, Gaetan Lecours, Duceppe Daniel

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Abstract

A variable ratio drive pulley designed for use in a belt drive transmission of a snowmobile includes fixed and movable flanges, the movable flange being controlled by centrifugally responsive thrust means employing pivoted weighted levers cooperating with shaped cam surfaces. The dynamic response of the pulley can be adjusted in a simple manner by abutment means supporting the ramps on which the cam surfaces are provided, these abutment means being accessible for adjustment from the exterior of the pulley.

Claims15

Dependent claims

A variable ratio drive pulley comprising:

two opposed frusto-conical flanges arranged coaxially with respect to a drive shaft to rotate therewith and impart a variable ratio drive to a transmission belt arranged between the flanges;
one said flange comprising a fixed flange that is fixed axially relatively to said shaft, and the other said flange being a movable flange that is movable axially of said shaft so that the frusto-conical front face thereof moves towards and away from the confronting frusto-conical face of the fixed flange;
biasing means operatively arranged between said shaft and said movable flange to urge the latter axially away from said fixed flange;
centrifugally responsive thrust means operative upon rotation of said drive pulley to generate an axially directed thrust force acting to urge said movable flange towards said fixed flange, the magnitude of said thrust force increasing with the speed of rotation of said drive pulley;
said thrust means comprising a plurality of weighted levers equiangularly spaced about the axis of said shaft, and a corresponding plurality of cooperating ramps, each lever being pivotally mounted at one end in the movable flange and having its opposite end positioned to cooperate with a respective range that is carried in a part that is fixed with respect to said drive shaft, and
adjustment means accessible from the exterior of said drive pulley and operative to alter the attitude of said ramps and thus the dynamic response of said thrust means, wherein each said ramp is supported at one point in its length upon an abutment mounted in said carrier, and at a second point spaced from said first point is carried upon a pivot mounting, said abutment being configured for engagement by a tool to be adjustable to alter the attitude of said ramp by moving it angularly about said pivot mounting, said adjustment being possible while said drive pulley remains fully assembled.

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Dependencies are inferred from the claim text.

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Abstract

A variable ratio drive pulley comprising:

two opposed frusto-conical flanges arranged coaxially with respect to a drive shaft to rotate therewith and impart a variable ratio drive to a transmission belt arranged between the flanges;
one said flange comprising a fixed flange that is fixed axially relatively to said shaft, and the other said flange being a movable flange that is movable axially of said shaft so that the frusto-conical front face thereof moves towards and away from the confronting frusto-conical face of the fixed flange;
biasing means operatively arranged between said shaft and said movable flange to urge the latter axially away from said fixed flange;
centrifugally responsive thrust means operative upon rotation of said drive pulley to generate an axially directed thrust force acting to urge said movable flange towards said fixed flange, the magnitude of said thrust force increasing with the speed of rotation of said drive pulley;
said thrust means comprising a plurality of weighted levers equiangularly spaced about the axis of said shaft, and a corresponding plurality of cooperating ramps, each lever being pivotally mounted at one end in the movable flange and having its opposite end positioned to cooperate with a respective range that is carried in a part that is fixed with respect to said drive shaft, and
adjustment means accessible from the exterior of said drive pulley and operative to alter the attitude of said ramps and thus the dynamic response of said thrust means, wherein each said ramp is supported at one point in its length upon an abutment mounted in said carrier, and at a second point spaced from said first point is carried upon a pivot mounting, said abutment being configured for engagement by a tool to be adjustable to alter the attitude of said ramp by moving it angularly about said pivot mounting, said adjustment being possible while said drive pulley remains fully assembled.

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