Maintaining power

In the second illustration the driving weight has reached its lowest point and the tensioning weight is now up, the clock needs to be wound by turning the winding wheel (or by pulling the chain), but during that time the main wheel continues to feel the driving force and the clock will not stop.

It was re-wound by the main train of the clock which turned the fourth pulley and was controlled by a lever attached to the tensioning weight.

Because these take much longer to wind, and are usually wound by trained staff, the bolt carries a segment of a gear wheel rather than a single pawl and is engaged manually.

In essence, the maintaining power consists of a disc between the driving drum of the clock and the great wheel.

When the pressure from the drum is removed for winding, the ratchet teeth on the edge of the disc engage a pawl and prevent it turning backward.