Mirror operating mechanism for single-lens reflex camera

Claim 1

A mirror operating mechanism in a single-lens reflex camera comprising: a mirror box housing; a first shaft; a first mirror holding frame holding a half-silvered mirror adapted to split light applied thereto from a photographing lens into a reflected portion and a transmitted portion, said first shaft pivotally coupling said first mirror holding frame to said mirror box housing; a second shaft; a second mirror holding frame holding a totally reflecting mirror for reflecting said transmitted portion from said half-silvered mirror, said second mirror holding frame being pivotally coupled to said first mirror holding frame by said second shaft; a rotation angle control plate coupled to said mirror box housing, said rotation angle control plate having a cam surface; a third shaft; a second mirror operating lever pivotally coupled to said first mirror holding frame by said third shaft; and a fourth shaft rigidly coupled to said second mirror holding frame, one end of said second mirror operating lever being slidably coupled through elongated grooves formed therein to said fourth shaft and the other end of said second mirror operating lever confronting said rotation angle control plate, wherein, as said first mirror holding frame is displaced from an observation position to a photographing position, said second mirror operating lever is turned relative to said first mirror holding frame with the aid of said cam surface of said rotation angle control plate to raise said second mirror holding frame with the aid of said elongated grooves of said second mirror operating lever.