Patent ID: 8739943

Claim:
A variable torque brake and drum system adapted to receive an elongated flexible restraining member which is pulled out with a progressively increasing restraining force on the member, said system comprising a fluid-tight hollow drum having a center axis and a generally cylindrical outer wall rigidly connected by opposite end walls, a shaft adapted to be supported for non-rotation and supporting said end walls of said drum for rotation of said drum on said axis relative to said shaft with fluid-tight seals between said end walls and said shaft, an annular actuating nut threadably mounted on said shaft and connected to said drum for rotation with said drum and for axial movement on said shaft in response to rotation of said drum, a stack of interfitting brake plates and brake disks within said drum with said brake plates connected to rotate with said drum and said brake disks connected for non-rotation with said shaft, a volume of liquid oil-shear cooling fluid confined within said drum for flowing between said brake plates and said brake disks, a set of compression springs extending axially between said actuating nut and said stack of interfitting brake plates and brake disks, said actuating nut being effective to compress said stack through said springs with increasing axial force in response to rotation of said drum relative to said shaft for progressively increasing the torque resistance on said drum and the restraining force on the flexible restraining member as said drum rotates, and said cooling fluid being effective to flow outwardly into contact with said outer wall of said drum in response to rotation of said drum for transferring friction heat from said stack to the air surrounding said system.