Pulley assembly for belt drive
A variable-speed belt drive pulley assembly includes a plurality of pulley segments, a plurality of sliders, and a rotatable hub. Each segment is adapted to engage a drive belt and is mounted to an outer end of a corresponding slider which is slidably received by the hub. Each slider may be a pair of rods extending from the body in parallel relationship to each other. The hub has a plurality of bores. Each bore slidably receives a corresponding one of the rods. An actuator device moves the segments radially inwardly and outwardly with respect to the hub. A coil spring is mounted on each the rods, and is biased to urge one of the segments radially outwardly.
1. A variable-speed belt drive pulley assembly, the assembly comprising:
a rotatable hub;
a plurality of pulley segments, each segment having a curved body adapted to engage a drive belt;
a plurality of sliders, each slider having an outer end attached to a corresponding one of the segments, and each slider having an inner end slidably received by the hub, each slider comprising at least two rods extending from the body in parallel relationship to each other, the hub having a plurality of bores, each bore extending generally inwardly from an outer surface of the hub, each bore slidably receiving a corresponding one of the rods;
an actuator device for moving the segments inwardly and outwardly with respect to the hub; and
a plurality of resilient members, each resilient member being mounted to a corresponding one of the rods, each resilient member being biased to urge one of the segments outwardly.
2. The drive pulley assembly of claim 1 , wherein:
each resilient member comprises a coil spring surrounding one of the rods.
3. The drive pulley assembly of claim 1 , wherein:
the hub is mounted to a shaft;
a sleeve is slidably mounted on the shaft; and
a plurality of arms are coupled to the sleeve, each arm having an inner end pivotally coupled to the sleeve and having an outer end pivotally coupled to a corresponding one of the segments.
4. The drive pulley assembly of claim 1 , wherein:
the plurality of bores form sets of bores which are parallel to each other and which are spaced apart on opposite sides of a line which extends radially outwardly from a central axis of the hub.
5. The drive pulley assembly of claim 1 , wherein:
each bore includes a larger diameter portion and a smaller diameter portion which are joined together by an annular shoulder, each shoulder engaging an end of a corresponding one of the resilient members.
6. The drive pulley assembly of claim 1 , wherein:
the hub forms a ground member of a four-bar mechanism.
7. A variable-speed belt drive pulley assembly, the assembly comprising:
a plurality of pulley segments, each segment being adapted to engage a drive belt, each segment having a curved body and a pair of rods extending from the body in parallel relationship to each other;
a rotatable hub, the hub having a plurality of bores, each bore extending inwardly from an outer surface of the hub, each bore slidably receiving a corresponding one of the rods;
an actuator device for moving the segments inwardly and outwardly with respect to the hub; and
a plurality of resilient members, each resilient member biased to urge one of the segments radially outwardly.
8. The drive pulley assembly of claim 7 , wherein:
the plurality of bores form sets of bores which are parallel to each other and which are spaced apart on opposite sides of a line which extends radially outwardly from a central axis of the hub.
9. The belt drive assembly of claim 7 , wherein:
each bore extends inwardly into the hub from an outer surface of the hub.
10. The drive pulley assembly of claim 7 , further comprising:
a plurality of resilient members, each resilient member being mounted to a corresponding one of the rods, each resilient member being biased to urge one of the segments radially outwardly.
11. The drive pulley assembly of claim 10 , wherein:
each bore includes a larger diameter portion and a smaller diameter portion joined together by an annular shoulder, each shoulder engaging an end of a corresponding one of the resilient members.
12. The drive pulley assembly of claim 7 , wherein:
the hub is mounted to a shaft;
a sleeve is slidably mounted on the shaft; and
a plurality of arms are coupled to the sleeve, each arm having an inner end pivotally coupled to the sleeve and having an outer end pivotally coupled to a corresponding one of the segments.
13. The drive pulley assembly of claim 7 , wherein:
each bore includes a larger diameter portion and a smaller diameter portion joined together by an annular shoulder, each shoulder engaging an end of a corresponding one of the resilient members.
14. A variable-speed belt drive pulley assembly, the assembly comprising:
a plurality of pulley segments, each segment being adapted to engage a drive belt, each segment having a curved body and a rod extending from the body;
a rotatable hub, the hub having a plurality of bores, each bore extending inwardly from an outer surface of the hub, each bore slidably receiving a corresponding one of the rods;
an actuator device for moving the segments inwardly and outwardly with respect to the hub; and
a plurality of resilient members, each resilient member biased to urge one of the segments radially outwardly.