The timing diagram below shows the sequence of operations that occur in a multiplication cycle during a full 360° rotation of the crank.
Recall that there is about 6mm of free play between the racks and the multiplier body. The rack frame begins to move at 0°, but the racks do not start their travel until 20°.
During this first 20°:
From 20° to 90° the racks move forward to drive the cross-shafts, adding the tens values to the accumulator register.
At 90° the rack frame begins its return stroke. The deadband allows time for the Add/Subtract cam to disengage the differentials before the racks begin to move at 110°.
Between 90° and 100° the carry lever assembly is lowered into engagement with the carry gears and drum. The carry actuating cams sweep past the 15 levers between 100° and 155°. The carry lever assembly rises just clear of the carry receiving gears at 165°, and the reset cams restore all the levers simultaneously at 170°. There is sufficient free time at either end of the carry cycle to reset another 4 places on the 20-digit machines.
The carry mechanism is entirely contained within the carriage, so it is quite practical for the carriage to be moving into its next position while the carries are in progress. The movement can begin as soon as the differentials have been disengaged. The shift cam (which rotates continuously throughout the cycle) begins to move the carriage at about 100°.
At 170° the rack frame has returned sufficiently far for the multiplier body to be clear of the horizontal locking blade. The vertical lock remains engaged.
Between 170° and 200°:
The cycle then repeats in the units position, but with three differences:
The crank returns to its stop at 360°, leaving the Tens/Units shift and the carry lever assembly halfway between their two operating positions.