Device for the braking of towing cables in tow-type ski lifts

A device for the braking of a towing cable in a tow-type ski lift, comprising a rotatable drum for carrying the towing cable, means associated with said drum for rotatably biasing said drum in one direction, whereby the tow cable is withdrawable from said drum against the force of said biasing means and is retractable about said drum by virtue of said biasing force, and means for hydraulically braking the withdrawal and retraction of the tow cable, said hydraulic braking means comprising a braking fluid impeller means rotatable with said drum and including a first set of impeller blade members, and a first relatively stationary stator disc having a first set of stator blade members cooperatively arranged adjacent the first set of impeller blade members, said first set of impeller and stator blade members all being equally inclined a predetermined angle with respect to the axis of rotation of the impeller means, the predetermined angle being such that braking force is generated when the drum is rotated in the cable withdrawal direction and such braking force is not substantially generated when the drum is rotated in the cable retraction direction;

• a second set of impeller blade members on said impeller means;
• and a second set of relatively stationary stator blade members cooperatively arranged adjacent the second set of impeller blade members, said second set of impeller and stator blade members being also equally inclined a predetermined angle with respect to the axis of rotation of the impeller means, the second set of impeller and stator blade members having a smaller radial dimension than the first set of impeller and stator blade members, the latter of said predetermined angles being such that braking force is generated when the drum is rotated in the cable retraction direction, and such braking force is not substantially generated in the cable withdrawal direction, whereby the braking action generated by said first set of impeller and stator blade members is greater than that generated by the second of said impeller and stator blade members when both impellers are rotated at the same speed, and whereby substantial braking forces are not generated by each respective impeller and stator blade set when braking forces are generated by the other impeller and stator blade set.