Abstract: A cocking mechanism for electric focal plane shutters arranged so that, in order to simplify the cocking mechanism, while a shutter opening controlling armature lever is brought to the cocked position from the uncocked position, a shutter closing controlling armature lever may be brought to the cocked position from the uncocked position by the shutter opening controlling armature lever and, when the shutter opening controlling lever is locked in the cocked position, the shutter closing controlling armature lever may be held in the cocked position.

Abstract: In each of the opening group and the closing group of shutter blades, there is a main blade and two auxiliary blades. When developing from a folded condition the blades of each group go from a more overlapped to a less overlapped condition. Although the same two springs may provide all three of the blades of a group with motive force for moving from the cocked to the uncocked condition, the two auxiliary blades have a driving force transmitter that is independently movable to a limited degree relative to the driving force transmitter for the main blade of the same group, one of the springs directly transmits force for moving the main blade and the other spring directly transmits force for moving the auxiliary blades.

Abstract: A shutter for cameras comprising a control cam, a starting lever to be used to release the control cam in the cocked state and bring a gear governor into an operatable state, a governor lever engageable with the control cam to operate the gear governor and a stopper capable of absorbing the inertia force of the governor lever to stop the motion of the governor lever, so that the gear governor for controlling the shutter speed may always operate positively over a long period and the operating sound of the shutter may be made low.

Abstract: A focal plane shutter comprising a pair of upper arms rotatably supported on a shutter base plate and arranged with a spacing between them, a pair of lower arms overlapped respectively on said pair of upper arms with a spacing, three main shutter blades respectively supported by said upper arms so as to have overlapped portions even when developed between the respective pairs of upper arms and lower arms, and two auxiliary shutter blades respectively supported by the lower arms so as to overlap on the above mentioned overlapped portions when developed between the respective pairs of the upper arms and lower arms, in order to make the entire shutter device or particularly the dimensions in the vertical direction smaller. Tail portions are formed respectively at the free ends of the main shutter in the middle and the auxiliary shutter blades.

Abstract: A light leakage preventing device for focal plane shutters made by interposing a shielding member between a view finder optical system and shutter base plates to intercept a light reaching a film surface through an air gap defined by the shutter base plates from within the view finder optical system. Said shielding member is moved from a light intercepting position to a non-light intercepting position by an interlocking lever operated between the operation of a release button of a photographic camera and the beginning of the operation of shutter blades and is moved from the non-light intercepting position to the light intercepting position simultaneously with the introduction of a light into the view finder optical system from an object to be photographed.

Abstract: A braking mechanism for focal plane shutters provided with a brake operating member pivoted in the tip portion of a shutter blade actuating member so as not to be freely movable and capable of taking an operating position and a non-operating position, a brake wheel supported rotatably with a proper resistance force on a shutter base plate and engageable with the brake operating member slightly before the end of the operation of the shutter blade actuating member and a stopper set on the shutter base plate and engageable with the shutter blade actuating member to stop the shutter blade actuating member so that a braking force may be efficiently applied to the shutter blade actuating member during a slight motion just before the end of the operation of said actuating member and then the braking means may not act as a load when said actuating member is stopped and the shutter is cocked.

Abstract: An electric shutter means so made that, in order to make the consumption of a current source battery as little as possible, during the period from the beginning of the operation of a self-timer by pressing a release button to the end of the operation, only the passage of an electric current to an electromagnet to start the motion of closing a rear blade may be prevented or a very small current may be made to flow to said electromagnet and, simultaneously with the closure of a current source switch by pressing the release button, an exposure warning circuit and exposure time indicating circuit may be held in an operating state.

Abstract: A shutter blade assembly wherein, in order to make the dimension of the focal plane shutter as small as possible, particularly in the vertical direction, a substantially rectangular main shutter blade for forming an exposure slit is pivotally connected at an end edge portion, located on the side of the shutter, to the ends of a pair of arms which are pivoted at their opposite ends to one side of an exposure aperture. The dimension in the vertical direction of the end edge portion is made larger than the dimension in the vertical direction of the remainder of the shutter blade. A plurality of auxiliary shutter blades for covering the exposure aperture are supported by being respectively pivoted at end edge portions to the arms adjacent the points of pivoting of the main shutter blade to the pair of arms.

Abstract: A built-in self-timer for cameras comprising a cocking member movable to the uncocked position and cocked position, a sector gear engageable with said cocking member and capable of being brought to the cocked position from the uncocked position by the cocking member, a checking member engageable with an interlocking member and capable of locking in the cocked position a delaying gear train meshed with the sector gear, and a locking member engaged with the checking member and engageable with the cocking member and interlocking member so that, even after the self-timer is set in the using state, if the cocking member is returned to the uncocked position, the delaying gear train may be automatically returned to the uncocked position and, at the same time, the checking member and locking member may be moved to a position of not engaging with the interlocking member.

Abstract: A mechanical exposure controlling means for electric shutters comprising a front blade actuating lever, a rear blade actuating lever, and a mechanical exposure controlling lever and bulb controlling lever which can be brought to a position in which they are engageable with the rear blade actuating lever so that, when said mechanical exposure controlling is brought to the position in which it is engageable with the rear blade actuating lever, an exposure may be made only at a specific shutter speed and, when said bulb controlling lever is brought to the position in which it is engageable with the rear blade actuating lever, a bulb exposure may be made. When the mechanical exposure controlling lever and bulb controlling lever are brought to the position in which they can be engaged with the rear blade actuating lever, the exposure time controlling circuit will be cut off from the current source battery.

Abstract: A high speed exposure time control means for focal plane shutters wherein, in order that an always accurate high speed exposure time may be obtained, a rear blade actuating member is so made as to be released after the lapse of a fixed time from the time of the shutter release and the time interval from the time of the shutter release to the time when a front blade actuating member is released is so made as to be varied by setting the exposure time.

Abstract: An electric shutter comprising a front blade actuating lever, a signaling lever engageable with said front blade actuating lever and a rear blade actuating lever capable of releasing said signaling lever so that the signaling lever may rotate fully in a predetermined range only at the time of such state that the rear blade actuating lever begins to move prior to the front blade actuating lever by the shutter release and the photographer may be informed by the rotation of the signaling lever of the fact that the exposing operation of the shutter is not being properly made.

Abstract: A focal plane shutter for cameras comprising two sets of shutter blades each of which comprises a plural number of opaque thin plates supported by two supporting arms, a partition plate for separating said two sets of shutter blades from each other, a pair of retaining plates for forming spaces between respective retaining plates and said partition plate for the purpose of housing said two sets of shutter blades separately from each other in said spaces, and an exposure aperture having opposing sides cut in a shallow V-shape. The overall size of said focal plane shutter small, and the shutter blades are moved smoothly at the time of operation without causing jamming or collision of the shutter blades.

Abstract: A photographic camera provided with a focal plane shutter having a plurality of vertically-movable shutter blades, in which at least a part of the leading-shutter blade consisting of a plurality of thin plates is positioned, in order to reduce the height of the camera as a whole, into the optical path of the view finder optical system of the camera when the leading-shutter blade has been brought into its opening position where it opens the exposure aperture in response to the shutter release.

Abstract: An electric shutter means which comprises a voltage checking circuit connected to an exposure time control circuit including an electromagnet for controlling the time of closing shutter blades so that, when the voltage of a power source battery for said exposure time control circuit has dropped to be below a predetermined level, the passage of electricity to said electromagnet may be forcibly interrupted by said voltage checking circuit.BACKGROUND OF THE INVENTIONa. Field of the InventionThe present invention relates to electric shutter means, and more particularly to an electric circuit to be applied to an electric shutter arranged so that, when the power source voltage has dropped to be below a predetermined level, the exposure time may be mechanically controlled with a specific shutter speed.B. Description of the Prior ArtA camera equipped with an electric shutter is generally provided with a voltage checking means.