Abstract: A system for positioning a plurality of carriages to preselected positions across a supported article includes moving a train of detachably interconnected carriages with an engine carriage functionally connected to a driving facility, and simultaneously detaching selected ones of the carriages from the train at predetermined positions across the article, in a sequential manner, beginning with the selected carriage farthestmost from the engine carriage, and holding the selected carriages to a member bridging the article. The positioning cycle is completed by stopping the engine train at its preselected position. Thereafter, a work operation is performed on the article by moving a work operation performing means associated with each of the selected carriages from an inoperative or retracted position to an extended or operative position.

Abstract: Pulses from a motor-driven roto pulser, e.g., primary pulses, and from a roto pulser powered by a moving ribbon, e.g., secondary pulses, are (1) compared to determine if the ribbon is continuous and (2) used to actuate ribbon cross scoring and snapping equipment. When the secondary pulse count exceeds the primary pulse count for a given ribbon displacement by more than a predetermined amount, indications are that a ribbon break has occurred and the scoring and snapping equipment is actuated by the pulses from the ribbon powered roto pulser. When the difference between the secondary pulse count and primary pulse count is less than the predetermined amount, indications are that the ribbon is continuous and the equipment is actuated by pulses from the motor-driven roto pulser.