Patent ID: 9207252
Filing Date: 2015-12-08
Classification: B65G,G01P

Abstract:
1. A speed detection apparatus comprising: a scale member including a plurality of detection marks continuously arranged at a predetermined pitch, the detection marks including a special mark identifiable from the other detection marks; first and second sensors spaced from each other by a predetermined distance larger than the predetermined pitch, and configured to detect the detection; a first detection unit configured to detect a reference speed of the scale member; a second detection unit configured to detect a time difference between time of detecting the special mark by the first sensor and time of detecting the special mark by the second sensor; a measurement unit configured to estimate a distance between the first sensor and the second sensor based on output of the second detection unit; a storage unit configured to store time when each of the first and second sensors detects a detection mark, and an address corresponding to the detection mark; an identification unit configured to identify, based on output of the first detection unit, time when the first and second sensors detect the same mark, from the address and the time stored in the storage unit; and a calculation unit configured to calculate, based on output of the identification unit, output of the first detection unit, and output of the measurement unit, a speed of the scale member.