Expanded interval timer drive mechanism

A program timer having a plurality of timing cams located on a rotating member and controlling the operation of switches in a predetermined program characterized by:

• a first ratchet ring mounted on said rotating member for movement therewith, said first ratchet ring having a first band of ratchet teeth over a first portion of its width and a second band of ratchet teeth over the remainder of its width, the ratchet teeth of said first band having uniform root and tip levels, said second band having at least one region with no ratchet teeth and being at a level below the root level of the ratchet teeth of said first band, the remainder of said second band having ratchet teeth which are coextensive with the ratchet teeth of said first band;
• a second ratchet ring arranged for free relative rotational movement in a first direction with respect to said rotating member, said second ratchet ring being in axial alignment with said first ratchet ring, the ratchet teeth of said second ratchet ring having uniform tip and root levels, said second ratchet ring being formed with at least one notch at a level below the root level of the second ratchet ring teeth and substantially the same as the level of the toothless region of said second band of said first ratchet ring;
• and
• a drive pawl selectively engaging said first and second ratchet rings to selectively drive same in said first direction, said drive pawl engaging said first ratchet ring in the arc length corresponding to said toothless region only when said drive pawl engages said notch of said second ratchet ring.