JPS6220823Y2 - - Google Patents

Description

[Detailed Description of the Invention] In the present invention, in an electric shutter, when the electromagnet is unable to attract and hold the iron piece due to battery exhaustion, circuit failure, etc., the mechanical mechanism automatically controls the predetermined exposure time. This invention relates to a mechanical time control mechanism.

As this type of control mechanism, for example,
A device disclosed in Japanese Patent No. 37740 is known.

In this conventional mechanism, the timing for retracting the holding member 20 that presses the iron piece member 17 to the electromagnet 16 from the crimping position is determined by the cam members 1 and 3 which are released from the lock by a release operation and moved, and The timing for retracting the lockable determination member 23 to the non-locking position via the control member 25.
The former must be set first, and in order to guarantee the timing, the movement strokes of the cam members 1 and 3 must be set long.

The object of the present invention is to provide a mechanical time control mechanism for an electric shutter that does not require timing settings as in the conventional mechanism described above and can ensure stable operation.

An embodiment of the present invention will be described below based on the drawings.

Reference numeral 1 denotes a release lever which is pivotally attached to a shaft 2 and given left rotation by a spring 3, and forms a hook portion 1a.

Reference numeral 4 designates an opening/closing lever which is pivotally connected to a shaft 5 and given left-handed rotation by a spring 6, and forms a relief portion 4a of the shaft 8, which will be described later, and a step portion 4b that is locked to the hook portion 1a. , a pin 4c having a large diameter part 4c' and a small diameter part 4c'' on the front side, and pins 4d, 4 on the back side.
e and are planted. Note that the opening/closing mechanism of the shutter blade (not shown) using pins 4d and 4e is disclosed in, for example, Utility Application No. 56-45785, which is an earlier application filed by the same applicant.
(Utility Model Application Publication No. 57-157935).

Reference numeral 7 denotes an iron piece lever which is pivotally connected to a shaft 8 and given left rotation by a spring 9, and has bends 7a and 7b formed therein and a pin 7c installed therein. 10
An iron piece is elastically attached to the bend 7a by a spring 11, and is placed opposite to an electromagnet connected to an output stage of an exposure time control circuit (not shown).

Reference numeral 12 denotes a determination lever which is pivotally mounted on a support shaft 7d on the iron piece lever 7 and is given left rotation by a spring 13 tensioned between it and the lever 7. It can be pushed by the arm portion 12b that is locked, the pronged portion 12c that pinches the bend 7b because the amount of rotation on the iron piece lever 7 is limited, and the small diameter portion 4c' of the pin 4c in the opening/closing lever 4. It forms a cam surface 12b.

Reference numeral 14 denotes a closing drive plate that is supported so as to be able to move in parallel and given a rightward movement habit by a spring 15;
a and the large diameter portion 4 of the pin 4c in the opening/closing lever 4
c'.

Reference numeral 16 denotes a closing release lever which is pivotally connected to the shaft 8 and given right-handed rotation by a spring 17.
The bend 16a that locks the pin 7c of the iron piece lever 7
The arm portion 16b is pushed by the arm portion 16b.

Reference numeral 18 denotes a pin fixedly arranged to restrain the arm portion 12a of the determination lever 12.

Next, the operation will be explained.

When a release operation is performed in the set state of FIG. 1, first a power switch of an exposure time control circuit (not shown) is closed, power is supplied to the circuit, and the electromagnet is excited. and,
When the electromagnet is properly excited, the iron piece 10 is attracted and held in the illustrated position, and when the electromagnet is not excited due to battery exhaustion or circuit failure, the iron piece 10 is placed in a movable state.

As the release operation progresses, the release lever 1 is rotated to the right against the tension of the spring 3, and the hook portion 1
a indicates the arm portion 12b of the determination lever 12 and the opening/closing lever 4
When the iron piece 10 is firstly attracted and held by the electromagnet, the iron piece lever 7 does not rotate to the left, and the judgment lever 12 is held on the iron piece lever 7 by the tension of the spring 13, so that the arm part 12a is pinned. 18, the cam surface 12d retreats from the movement range of the small diameter portion 4c'' of the pin 4c in the opening/closing lever 4, and the opening/closing lever 4 subsequently rotates to the left due to the tension of the spring 6, as shown in FIG. The shutter blade (not shown) was opened and its state is shown in FIG.

Thereafter, when the output signal of the exposure time control circuit that started photometric timing in response to the opening movement of the shutter blade is reversed and the electromagnet is demagnetized, the iron piece lever 7 releases the iron piece 10 from being attracted and held, and the spring 9, the arm portion 16b is pushed by the pin 7c, the closing release lever 16 is rotated to the left against the tension of the spring 17, and the bent portion 16a is removed from the stepped portion 14a. Therefore, the closing drive plate 14 moves to the right due to the tension of the spring 15, pushes the large diameter portion 4c' of the pin 4c with the end surface 14b, and causes the opening/closing lever 4 to rotate clockwise against the tension of the spring 6. to close the shutter blade halfway from opening or from the fully open position.

In addition, if the above-mentioned iron piece 10 is not held by the electromagnet, the hook part 1 of the release lever 1
When a comes off the arm 12b of the determination lever 12,
The iron piece lever 7 immediately rotates to the left, but the judgment lever 1
2's arm 12a is restrained by the pin 18, the pin 7c is restrained by the arm 1 of the closing release lever 16.
6b stops turning to the left, and the cam surface 12d of the judgment lever 12 remains in the range of motion of the small diameter portion 4c'' of the pin 4c in the opening/closing lever 4, and by turning the opening/closing lever 4 to the left, Small diameter part 4
FIG. 3 shows the state in which the cam surface 12d begins to come into contact with the cam surface 12d.

Thereafter, the opening/closing lever 4 continues to rotate to the left, and the cover surface 12d is pushed by the small diameter portion 4c'', causing the determination lever 12 to move forward.
is rotated to the left on the iron lever 7, and the arm 1
When 2a is removed from the pin 18, the iron lever 7 rotates to the left again and closes the shutter blade in the same manner as described above. The exposure time in this case is a constant mechanical second independent of the field brightness.

If the shutter is, for example, a program lens shutter that also serves as an aperture blade, this constant mechanically controlled time provides an exposure amount that corresponds to around EV13, which is the field brightness that is commonly used. value is preferred.

Further, the setting operation of the shutter mechanism is performed by moving the closing drive plate 14 to the left against the tension of the spring 15 using a setting member (not shown) from the end state of each exposure operation to close the stepped portion 14a. While engaging the bend 16a of the release lever 16, the determination lever 12 pivotally mounted on the iron piece lever 7 is rotated to the right about the axis 8 together with the iron piece lever 7 against the tension of the spring 9. 12b is engaged with the hook portion 1a of the release lever 1.

Note that when the closing drive plate 14 is bent and moves to the right, the opening/closing lever 4 is rotated to the right and returned to the state shown in FIG. 1 (slightly overrun). Similarly, if the determination lever 12 can be turned to the right by the bending as described above, only the closing drive plate 14 needs to be moved to the left during the setting operation.

A limiting member corresponding to the pin 18 can also be formed on the closing drive plate 14.

Furthermore, the present invention can be applied to a type in which two sets of shutter blades are used, one for opening and one for closing.
Therefore, it can also be applied to focal plane shutters.

As described above, in the present invention, the automatic time control state and the mechanical time control state are set by simply determining whether or not the iron piece member is attracted and held by the electromagnet.
Stable operation can be obtained in each case.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention in a set state, Fig. 2 is an explanatory diagram showing a state in the middle of operation during automatic time control, and Fig. 3 is an explanatory diagram showing a state in the middle of operation during mechanical time control. It is an explanatory diagram showing a state. Opening driving member (opening/closing lever 4), iron piece member (iron piece lever 7, iron piece 10), determination member (judgment lever 12), restriction member (pin 18), closing driving member (closing driving plate 14).

Claims (1)

[Scope of Claim for Utility Model Registration] The shutter blade opening drive member (opening/closing lever 4) that moves when the lock is released by the release operation.
and an electromagnet connected to the output stage of the exposure time control circuit, which is excited when the power switch is closed at the beginning of the release operation and demagnetized by the reversal of the output signal of the control circuit; an iron piece member (iron piece lever 7, iron piece 10) which ensures the tension state of the closing drive member (closing drive plate 14) of the shutter blade at the crimping position with respect to the electromagnet; The iron piece member is pivotally mounted for fixed rotation, and is tension-locked in a state in which rotation is limited in one direction relative to the iron piece member, so that the iron piece member is crimped to the electromagnet, and the iron piece member is pressed against the electromagnet in the opposite direction. It consists of a determining member (determining lever 12) that is given a rotational habit in a direction, and a control member (pin 18) arranged so as to prevent the determining member from moving. When the stop is released by a release operation and the iron piece member is attracted and held by the electromagnet, it rotates on the iron piece member by its own habit without coming into contact with the limiting member, and then By allowing the iron piece member to move away from the electromagnet and retreating from the movement range of the opening drive member, and when the iron piece member is not attracted and held by the electromagnet, it is displaced together with the iron piece member. , comes into contact with the limiting member, temporarily stops the separation movement of the iron piece member within a range that can guarantee the tension state of the closing drive member, and remains in the movement range of the opening drive member, and then the release movement of the iron piece member 1. A mechanical time control mechanism for an electric shutter, characterized in that it is rotated on the iron piece member by contact, and is released from contact with the limiting member to allow the separation movement of the iron piece member.