Tensioning device for aircraft refueling boom hoist

Abstract

A power spring passively applies tension to a cable connected to an aircraft refueling boom. The power spring has a first end engaging a fixed arbor and second end engaging a rotatable spooling drum around which a portion of the cable is wound. The power spring biases the drum to rotate in a winding direction to apply tension to the cable, and the power spring stores energy when the drum rotates in an unwinding direction. The power spring may be located inside the drum or outside the drum. The drum may be actively driven by a motor that may be uncoupled from the drum to permit freewheeling rotation of the drum, wherein the power spring continues to apply tension to the cable. The invention eliminates reliance on one or more powered motors for removing unwanted slack in the cable.

What is claimed is: 
     
         1 . An apparatus for applying tension to a cable connected to an aircraft refueling boom, the apparatus comprising:
 an arbor;   a hollow drum rotatable about an axis relative to the arbor, a portion of the cable being wound externally around the drum; and   a power spring including a first end engaging the arbor and a second end engaging the drum;   wherein the power spring biases the drum to rotate in a winding direction to apply tension to the cable, and the power spring stores energy when the drum rotates in an unwinding direction.   
     
     
         2 . The apparatus according to  claim 1 , wherein the power spring is housed within the drum. 
     
     
         3 . The apparatus according to  claim 1 , wherein the power spring is outside the drum. 
     
     
         4 . The apparatus according to  claim 1 , wherein the first end of the power spring is an inner end of the power spring, and the second end of the power spring is an outer end of the power spring. 
     
     
         5 . The apparatus according to  claim 1 , wherein the first end of the power spring is an outer end of the power spring, and the second end of the power spring is an inner end of the power spring. 
     
     
         6 . The apparatus according to  claim 1 , further comprising a motor operable to rotate the drum in the winding direction. 
     
     
         7 . The apparatus according to  claim 6 , wherein the motor is a hydraulic motor. 
     
     
         8 . The apparatus according to  claim 6 , wherein the motor is an electric motor. 
     
     
         9 . The apparatus according to  claim 6 , further comprising a clutch and gearing operable to selectively couple the motor to the drum, wherein the drum is in a freewheeling state when uncoupled from the motor and the power spring applies tension to the cable when the drum is in the freewheeling state. 
     
     
         10 . The apparatus according to  claim 9 , wherein the gearing comprises a differential gear train, and the clutch is arranged to act on an element of the differential gear train. 
     
     
         11 . The apparatus according to  claim 10 , wherein the clutch is hydraulically actuated. 
     
     
         12 . The apparatus according to  claim 10 , wherein the clutch is actuated by a solenoid. 
     
     
         13 . An aircraft refueling boom system comprising:
 a refueling boom deployable from a stowed position to a refueling position and returnable from the refueling position to the stowed position;   a cable connected to the refueling boom;   a tensioning apparatus for applying tension to the cable, the tensioning apparatus comprising an arbor, a hollow drum rotatable about an axis relative to the arbor, and a power spring having a first end engaging the arbor and a second end engaging the drum, wherein a portion the cable is wound externally around the drum;   wherein the power spring biases the drum to rotate in a winding direction to apply tension to the cable, and the power spring stores energy when the drum rotates in an unwinding direction.   
     
     
         14 . The system according to  claim 13  wherein the power spring is housed within the drum. 
     
     
         15 . The system according to  claim 13  wherein the power spring is outside the drum. 
     
     
         16 . The system according to  claim 13  wherein the first end of the power spring is an inner end of the power spring, and the second end of the power spring is an outer end of the power spring. 
     
     
         17 . The system according to  claim 13  wherein the first end of the power spring is an outer end of the power spring, and the second end of the power spring is an inner end of the power spring. 
     
     
         18 . The system according to  claim 13  further comprising a motor operable to rotate the drum in the winding direction. 
     
     
         19 . The system according to  claim 18  wherein the motor is a hydraulic motor. 
     
     
         20 . The system according to  claim 18 , wherein the motor is an electric motor. 
     
     
         21 . The system according to  claim 18 , further comprising a clutch and gearing operable to selectively couple the motor to the drum, wherein the drum is in a freewheeling state when uncoupled from the motor and the power spring applies tension to the cable when the drum is in the freewheeling state. 
     
     
         22 . The apparatus according to  claim 21 , wherein the gearing comprises a differential gear train, and the clutch is embodied as a brake arranged to act on an element of the differential gear train. 
     
     
         23 . A method comprising the steps of:
 providing a refueling boom, a cable connected to the refueling boom, and a drum, wherein a portion of the cable is wound around the drum and the drum is rotatable about an axis in a winding direction and an opposite unwinding direction; and   passively applying force to the drum without the use of a motor to urge the drum to rotate in the winding direction to thereby passively apply tension to the cable.   
     
     
         24 . The method according to  claim 23 , wherein the passively applied force is provided by a power spring connected to the drum. 
     
     
         25 . The method according to  claim 24 , wherein the power spring is located inside the drum. 
     
     
         26 . The method according to  claim 24 , wherein the power spring is located outside the drum.