| 摘要 |
An adjustable belt-and-pulley transmission wherein a rotary shaft carries a pulley composed of a side wall which is fixed to the shaft and an adjustable side wall which is axially movable along the shaft while being constrained to rotate therewith. These pulley side walls have inner tapered surfaces forming parts of cones whose apexes coincide with the axis of the shaft so that a belt engaging these surfaces can have its radial distance from the shaft regulated in accordance with the axial distance of the adjustable pulley side wall from the fixed side wall thereof. The adjustable pulley side wall has an elongated collar fixed thereto and surrounding the shaft with clearance, this collar being formed with an elongated slot which extends longitudinally of the shaft. Between the collar and the shaft is a longitudinally slit wear-resistant, self-lubricating, resilient sleeve which prevents direct contact between the collar and the shaft and which because of the slit is capable of automatically expanding and contracting around the shaft and within the collar in response to temperature changes. A motion-transmitting structure is fixed to the shaft and extends through the sleeve into the slot of the collar for providing transmission between the adjustable pulley wall and the shaft, and this motion-transmitting structure has within the slot of the collar a covering material which is wear-resistant and resilient for directly engaging one or the other of the side surfaces of the slot of the collar so as to prevent wear and reduce friction at the point of engagement between the motion-transmitting structure and the adjustable pulley wall. An elongated cover covers the slot and covers the motion-transmitting structure, and this cover is surrounded by a bearing structure which is carried by the collar and which serves to retain the cover at the slot, an adjusting structure being connected to the bearing for acting through the latter on the adjustable pulley side wall for shifting the latter axially with respect to the shaft.
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