| 摘要 |
A pivoting joint connected between a first part and a second part of an instrument, permitting the first part to be turned relative to the second part and retained at one of a series of angular positions, including a first coupling member with a ratchet fastened to the first part of the instrument, a shaft mounted in an axle hole in the second part of the instrument, a sleeve and a spring holder mounted around the shaft within the axle hole of the second part of the instrument and forced by spring means to hold down the shaft, and a second coupling member fixedly mounted on the shaft and having a ratchet meshed with the ratchet of the first coupling member. |
