HIGH SPEED VARIABLE RATIO PULLEY

• US 3,759,111 A
• Filed: 02/05/1973
• Issued: 09/18/1973
• Est. Priority Date: 02/05/1973
• Status: Expired due to Term

• Current Assignee: Stephen J. Hoff
• Original Assignee: Stephen J. Hoff
• Inventors: Hoff, Stephen J.
• Primary Examiner(s): Myhre, Charles J.
• Assistant Examiner(s): Lazarus, R. H.
• Application Number:
  US05/329,721
• Time in Patent Office: 225 Days
• Field of Search: 74/23.17E 192/15C,89W
• US Class Current: 474/14
• CPC Class Codes: F16H 55/563 actuated by centrifugal masses
• CPC Class Codes: F16H 61/66227 controlling shifting exclusively as a function of speed and torque

Abstract

Improved safety and operation is obtained in a high-speed variable ratio pulley having a movable pulley flange which is driven rotatively by torque transmitting engagement between fixed spider arms and drive posts adjacent the periphery of the movable pulley flange, and is thrust axially toward a fixed pulley flange by centrifugal cam levers acting between the movable pulley flange and the spider arms. The drive posts closely straddle the thrust line and are long enough to give clearance for the intended flange movement, and their ends are tied together by a tie plate and a ductile bell housing which also engage an outboard bearing to support the posts and movable pulley flange against tilting. Cam movement of the pulley flange is limited, in one case by providing the cam levers with hooked ends which stop their swing at a point short of thrusting the movable pulley flange into forceful abutment with the fixed pulley flange, and in another case by positioning the tie plate to move as a stop against the ends of the spider, substantially on the cam thrust line. For special applications, the spider is adjustably positioned to provide different cam locations and engaging speeds.

Claims

1. A high-speed variable-ratio pulley, comprising a fixed pulley flange defining one side of a V-groove and adapted to be fixed coaxially on a shaft, a movable pulley flange defining the opposite side of the Vgroove, slidable axially of the shaft to vary the width of the V-groove, a plurality of pairs of drive posts extending rearward from adjacent the periphery of the movable pulley flange, a fixed drive spider behind the movable pulley flange and having a plurality of drive arms each received between the posts of a pair of posts in axially-slidable, torque-transmitting relation with said posts for transmitting drive torque between ends of the spider arms and the movable pulley flange, centrifugal means located between the posts of each pair and acting between a point on the movable pulley flange at the base of said posts and the drive arm received therebetween to urge such pulley flange away from the arm and thereby urge the pulley flanges together, an inboard bearing between the movable pulley flange and the shaft and an outboard bearing about the shaft outward of the fixed spider, wherein the improvement comprises a tie plate fixed to the ends of the several pairs of drive posts and to the outboard bearing, to tie the ends of the posts of each pair together and to the other posts and the outboard bearing, to reinforce the posts against centrifugal failure And form a connection from said outboard bearing through the posts to brace the movable pulley flange against tilting movement on the shaft.

2. A high speed variable-ratio pulley as in claim 1 in which said fixed pulley flange is fixed to an elongated hub adapted to be fixed on a shaft, said inboard and outboard bearings are slidably received on bearing surfaces carried by said hub, and said spider is fixed on said hub between the movable pulley flange and the outboard bearing.

3. A variable ratio pulley as in claim 2 which includes a bell housing of steel or like strong ductile material fixed to the drive posts and tie plate and extending therefrom to the movable pulley flange to enclose the drive mechanism.

4. A variable-ratio pulley as in claim 1 with the addition of stop means to stop the action of the centrifugal means at a predetermined relative position of the pulley flanges and thereby prevent further thrust on the movable pulley beyond said position.

5. A variable ratio pulley as in claim 4 in which said centrifugal means comprises cam followers on the spider arms or the movable pulley flange and centrifugal cam levers pivoted to the other thereof and movable by centrifugal force against the followers to generate axial thrust urging the pulley flange away from the spider, and said stop means comprises means to stop centrifugal movement of the cams beyond a predetermined position relative to the followers and thereby prevent thrust on the movable flange beyond a predetermined position of the movable pulley flange relative to the fixed pulley flange.

6. A variable ratio pulley as in claim 5 in which said cam followers are rollers and said cam levers swing outward against the rollers and thereby produce axial thrust on the movable pulley flange, and said stop means include shaped portions on the cams for radially engaging the rollers to stop further centrifugal movement of the cams.

7. A variable ratio pulley as in claim 4 in which said centrifugal means comprises cam followers on the spider arms or the movable pulley flange and centrifugal cam levers on the other thereof and movable by centrifugal force against the followers to generate axial thrust urging the pulley flange away from the spider, the portions of said tie plate connecting the posts of each pair being positioned to engage the spider arm disposed between such posts as the movable pulley flange and its connected parts move to said predetermined position relative to the fixed pulley flange so as to stop further movement thereof and form said stop means.

8. A variable ratio pulley as in claim 7 in which each set of cam follower and cam lever is positioned substantially between and in line with a pair of posts and generates axial thrust along thrust lines between or close to said posts so that when said stop means is engaged, additional thrust generated by said centrifugal means will be transmitted directly to said posts to stress the same in tension, substantially without imposing bending stress on the posts or other parts of the mechanism.

9. A high speed variable-ratio pulley as in claim 1 in which said centrifugal means comprises cam followers on the spider arms or the movable pulley flange and centrifugal levers pivoted to the other thereof and having an inward-extending normal position from which they are movable by centrifugal force against the followers to generate axial thrust urging the pulley flange away from the spider, there being positioning means at the hub of the spider and engageable by the movable pulley flange to determine the relative axial positions of said spider and flange in the fully retracted position of the latter, said positioning means being variable to vary said relative positions and thereby vary the spacing between the cam followers and the pivot mountings of the cam levers to accommodate cam levers of different centrifugal-response characteristics.

10. A high speed variable ratio pulley as in claim 9 in which said position means comprises a sPacer ring between the spider hub and a shoulder on the hub of the fixed pulley flange.

11. A high speed variable ratio pulley as in claim 1 in which said drive posts define guide ways in the form of opposed axially extending concave grooves of cylindrical configuration, and said drive arms are fitted with bearing pads having cylindrical outer faces mating with said concave grooves.