How The Combination Lock Works (concl.)
The latch assembly is has a flat spring attached to it. Unless there is force on the shackle, the flat spring holds the latch assembly and pawl away from the cams while the combination is dialed, so the pawl will not touch and drag on the cams. Thus, the dial turns freely.

Note that the latch assembly has a separate latch piece that fits into the shackle. This piece is pushed by a spring inside the latch assembly, and is beveled like a standard door latch. When the shackle is pulled out of the lock, one of the features of the lock, described later, moves the back cam out of alignment. When the shackle is pushed back into the lock, the latch assembly will not pivot, because the back cam blocks the pawl. This latch piece is pushed back into the latch assembly, the same way a beveled door latch is pushed into a door when the door is closed. When the shackle is pushed deep enough into the lock, the piece pops out into the notch of the shackle. Then, the shackle can not be pulled out of the lock.

If the deep notch on any one of the cams is not aligned under the pawl, that cam will block the pawl when the shackle is pulled. The latch assembly will not pivot, and the lock will not open.

When more than one deep notch is not aligned, the misaligned cams will block the pawl when the shackle is pulled. However, if one cam has a greater radius than the other two, the pawl will ride on it and not reach the other two cams.

The front cam is larger than the other two cams, but it has eleven shallow notches. These shallow notches make the process of locating the deep notch more difficult.

The picture below shows the lock without its case. The critical parts: dial (upside down), three cams, latch assembly, flat spring and shackle are visible.

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