| 摘要 |
PURPOSE:To drive the title device exuctly without influence due to dust or the like from the external by contacting a contact pin always with an external contact by pressure due to a compression spring and driving a switch contact device for fusing an automatic diaphragm signal circuit so as to interlock with the movement of a switching pin formed coaxially with the contact pin. CONSTITUTION:When a mount ring 11 is fitted to a camera body, the contact pin 20 is abutted and pressed upon an external contact 31 on the camera body 30 side and a compression spring 22 is compressed to obtain contact pressure between the contact pin 20 and the external contact 31. When a diaphragm preset ring 13 is turned to an automatic diaphragm position, i.e. when an automatic diaphragm display 16 is made to coincide with a fixed index 17, the position of a switching groove 25 formed on a back end surface 13a also coincides with that of a switching pin 21. The switching pin 21 is projected into the switching groove 25 by the force of the compression spring 22 and a flange 21a is contacted with a contact washer 26. Consequently, an automatic diaphragm signal circuit including a circuit from the external contact 31 to the mount ring 11 is completed and a signal related to automatic diaphragm is transmitted/ received between the camera body and an interchangeable lens.
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