Focal plane shutter device for a camera

Abstract

A focal plane shutter device is provided in which when a rear shutter diaphragm travels in a first direction to retract from a photographing image plane from a state where the rear shutter diaphragm and a front shutter diaphragm shade the photographing image plane doubly, a balancer (42 and 44) travels in a direction which is substantially opposite to the first direction. When the front shutter diaphragm travels in a second direction opposite to the aforesaid first direction to begin exposure subsequent to the retraction of the rear shutter diaphragm, the aforesaid balancer (42 and 44) travels in a direction substantially opposite to the second direction. Consequently, it is possible to prevent camera blurring due to the traveling of the rear shutter diaphragm and the front shutter diaphragm by one balancer means. The device preferably includes an assisting member (45) which is connected to the balancer and which is caused to travel so as to provide a pressing force to assist the rear shutter diaphragm when the rear shutter diaphragm travels in the first direction, thus making it possible to perform the retraction of the rear shutter diaphragm more reliably. A chasing member may also be provided to chase the assisting member and secure a space between the front and rear shutter diaphragms by contacting the assisting member if, for example, the rear shutter diaphragm begins to travel prematurely by malfunction.