Why do the wheels of traditional mechanical combination locks need to be aligned with the scale lines?

The wheels of traditional mechanical combination locks need to be aligned with the scale lines, mainly based on the following design principles and mechanical structure requirements:

1. Mechanical linkage unlocking mechanism

(1) Alignment of wheel grooves is a prerequisite for unlocking

Each wheel has a specific groove. Only when the grooves of all wheels are completely aligned can mechanical parts such as the lock tongue, the stopper or the fence move through the gap formed to release the lock state.

(2) Scale lines as a visual indication of alignment

The scale lines provide users with operation guidance to ensure that the wheel rotates to the correct angle.

2. Machining and error control

(1) Dealing with mechanical manufacturing errors

Due to the perception error (about 3.6 degrees/scale) and processing error when the knob is turned, a tolerance range of ±1.5 scales is allowed in the actual design. The alignment design of the scale lines balances accuracy and practicality by expanding the valid password range (such as 50 valid scales).