Patent ID: 8545115
Filing Date: 2013-10-01
Classification: G03B

Abstract:
1. A focal plane shutter for cameras, in which two blade rooms are formed by separating a space between a shutter base plate and an auxiliary base plate by a middle plate, an exposure aperture is formed by at least one of opening portions on these three plates for guiding light from an object, first and second blade groups arranged in the blade rooms respectively include a plurality of elongate blades, and, in exposure operation, the first blade group changes from the unfolded state of the blades of the first blade group to the folded state of the blades of the first blade group to open the exposure aperture and the second blade group changes from the folded state of the blades of the second blade group to the unfolded state of the blades of the second blade group to close the exposure aperture, wherein a second plate which forms the blade room for the second blade group in cooperation with the middle plate is provided with a push pin which is planted on the middle area of the second plate between an exposure aperture-forming side toward which the shutter blade groups move in exposure operation and an outer contour-forming edge of the second plate, the middle plate is pushed by the push pin to bend toward a third plate of the three plates, and the middle plate is formed in such a way that an area of the middle plate external to the exposure aperture-forming side of the second plate has the narrowest width in the portion which is pushed by the push pin and, as two width-defining edges defining the width of the area of the middle plate external to the exposure aperture-forming side of the second plate extend from the narrowest portion to the both ends of the exposure aperture-forming side of the second plate more and more, the width-defining edge on the exposure-aperture side gradually comes near to the both ends of the exposure aperture-forming side of the second plate and the other width-defining edge gradually comes near to the outer contour-forming edge of the second plate.