What is "monkey wheel"

Gin \Gin\, n. [A contraction of engine.]

1. Contrivance; artifice; a trap; a snare.
   --Chaucer. Spenser.

2. 1. A machine for raising or moving heavy weights, consisting of a tripod formed of poles united at the top, with a windlass, pulleys, ropes, etc.

   2. (Mining) A hoisting drum, usually vertical; a whim.

3. A machine for separating the seeds from cotton; a cotton gin. Note: The name is also given to an instrument of torture worked with screws, and to a pump moved by rotary sails. Gin block, a simple form of tackle block, having one wheel, over which a rope runs; -- called also whip gin, rubbish pulley, and monkey wheel. Gin power, a form of horse power for driving a cotton gin. Gin race, or Gin ring, the path of the horse when putting a gin in motion. --Halliwell. Gin saw, a saw used in a cotton gin for drawing the fibers through the grid, leaving the seed in the hopper. Gin wheel.

   1. In a cotton gin, a wheel for drawing the fiber through the grid; a brush wheel to clean away the lint.

   2. (Mining) the drum of a whim.