Apparatus for Retrieving a Gravitationally Propelled Load Traveling on a Cable

Abstract

In connection with a gravitationally propelled load carrying system that includes an elongated suspended cable having a load carrying trolley movably supported thereon, an empty trolley retriever assembly adapted to push the empty trolley upwardly on the cable to be in position to take on a load where the assembly includes a plurality of idler pulleys rotationally carried by a base member where each of the pulleys is disposed in rolling engagement with the upper side of the cable to movably support the retriever assembly on the cable at a position intermediate the trolley and the lower terminal end of the cable, a motor driven drive wheel disposed intermediate the idler pulleys that engages the lower side of the cable, and a remotely operable control electrically connected to the motor for operatively rotating the drive wheel and propelling the retriever.

I claim: 
     
         1 . A zip line system comprising,
 an elongated zip line cable with upper and lower terminal ends and top and bottom sides,   means for supporting the upper and lower ends of the cable,   a trolley movably supported on the cable,   a trolley retriever assembly disposed on the cable intermediate the trolley and the lower support and having,
 means for reversibly driving the retriever assembly up and down the cable, and 
 a pusher rod attached to the retriever assembly and adapted to engage the trolley to push the trolley upwardly on the cable. 
   
     
     
         2 . The system of  claim 1  where the trolley retriever assembly further comprises,
 a base, 
 a plurality of idler pulleys rotationally carried by the base in rolling engagement with the top side of the cable to movably support the assembly on the cable. 
 
     
     
         3 . The system of  claim 2  and further including,
 means for pressure biasing each of the idler pulleys downwardly against the cable. 
 
     
     
         4 . The system of  claim 3  and further including,
 a shaft on which each of the idler pulleys is mounted, 
 a pivotal arm carried by the base and supporting the shaft, 
 a spring interacting between the base and the arm to pressure bias the respective idler pulley downwardly against the cable. 
 
     
     
         5 . The system of  claim 4  where the means for reversibly driving the assembly up and down the cable includes,
 a reversible variable speed electric motor carried by the base, 
 means for reducing the speed of the motor having an output drive shaft, 
 a circular drive wheel attached to the output drive shaft and disposed to make contact between the periphery of the drive wheel and the underside of the cable. 
 
     
     
         6 . The system of  claim 5  where the drive wheel includes an elastic foam filled tire. 
     
     
         7 . A gravitationally propelled load carrying system comprising,
 an elongated suspended cable with upper and lower terminal ends and upper and lower sides,   means for supporting the upper and lower terminal ends of the cable,   a load carrying trolley movably supported on the cable,   an empty trolley retriever assembly having,
 means for engaging the empty trolley to push the trolley upwardly on the cable, 
 a base member, 
 a plurality of idler pulleys rotationally carried by the base member where each of the pulleys is disposed in rolling engagement with the upper side of the cable to movably support the retriever assembly on the cable at a position intermediate the trolley and the lower support means, 
 a rotatable drive wheel engaging the lower side of the cable and disposed intermediate the idler pulleys, 
 means for operatively rotating the drive wheel, and 
 a remotely operable control electrically connected to the means for operatively rotating the drive wheel. 
   
     
     
         8 . The gravitationally propelled load carrying system of  claim 7  and including means for applying idler pulley biasing pressure against the cable to produce frictional engagement between the cable and the drive wheel. 
     
     
         9 . A method for repositioning a load carrying trolley from the lower terminal end of an inclined carrying cable back to the upper end of the cable, comprising the steps of,
 positioning a motor driven retriever at the bottom terminal end of the cable,   releasing a gravity driven load carrying trolley to travel down the cable and engage the retriever,   activating the motor driven retriever to push the trolley back up the cable, and   returning the retriever to the bottom terminal end of the cable.   
     
     
         9 . The method of  claim 8  where the step of returning the retriever to the bottom terminal end includes the step of,
 activating the motor driven retriever to travel down the zip line cable at a speed greater than that which would be produced by gravitational pull.