A mechanism to maintain a clock's drive during the operation of winding. The poor accuracy of pre-pendulum clocks meant that there was little need to keep them going during winding. The Christiaan Huygens endless rope or chain provides the simplest maintaining power. A continuous band of rope is run over two pulleys, forming two loops. The driving weight hangs in one loop with a smaller weight or lead ring hanging in the other to tension the system. In a striking clock, one of the top pulleys drives the striking train through a ratchet and click, the other pulley being fixed to the great wheel of the going train. The clock is wound by pulling down the length of rope between the smaller weight and the striking-train pulley. This raises the larger weight without removing its effect from the going train, and one weight drives both trains. The problem with this system is that it is difficult to arrange for the clock to run for longer than 30 hours, whereas in timepieces the top pulley with its rathet is attached to the case or movement, allowing the timepiece to run for up to eight days. In a domestic or turret clock fitted with bolt and shutter maintaining power, the shutter(s) normally covering the winding square(s) can be raised by moving a lever or pulling a cord, which at the same time raises a small weight, coupled with a train wheel by the bolt or a click, to drive the clock during winding.