JP6396096B2 - Focal plane shutter for camera and camera equipped with the same - Google Patents

Description

  The present invention relates to a focal plane shutter for a camera and a camera including the same.

  Conventionally, as a technique in such a field, for example, there is the following Patent Document 1. In the camera shutter device described in Patent Document 1, in addition to the leading blade electromagnetic drive source 60 and the trailing blade electromagnetic drive source 70 that directly exert driving force on the leading blade group 40 and the trailing blade group 50, respectively, An electromagnetic drive source 80 is disposed. Then, the electromagnetic driving source 80 for restriction engages with the first driven portion 45a and the third driven portion 55a of the leading blade support arm 45 and the trailing blade support arm 55 in the standby state, and Restrict movement.

  Further, after the release button is pressed and before the exposure operation, the second pressed portion 45b of the leading blade support arm 45 and the fourth driven portion 55b of the trailing blade support arm 55 are engaged to play back. To position the exposure operation start position. That is, the urging force of the regulating electromagnetic drive source 80 acts in a direction that antagonizes the holding force of the leading blade electromagnetic driving source 60 and the trailing blade electromagnetic driving source 70, so that the leading blade group 40 and the trailing blade group 50 Since it is positioned at the exposure operation start position, a stable exposure operation can be surely performed.

JP 2002-55378 A

  However, in the camera shutter device described in Patent Document 1, a dedicated regulating electromagnetic drive source 80 is provided to position each blade group at the exposure operation start position, which complicates the structure and reduces the number of parts. There is a risk of increasing the cost of the product due to an increase or the like and increasing the size of the shutter device.

  This invention makes it an example of a subject to cope with the said situation. That is, in the focal plane shutter of the type that directly drives the blade group using an electromagnetic drive source such as a motor, the blade group is exposed to the exposure operation start position while reducing the cost by simplifying the structure and reducing the number of parts. It is an object of the present invention to provide a focal plane shutter for a camera that can be surely positioned and surely perform a stable exposure operation, and a camera including the same.

  In order to achieve the above object, a focal plane shutter for a camera according to the present invention includes a base plate and an auxiliary base plate that have an opening for a subject optical path and form a blade chamber therebetween, and are rotatably attached to the base plate. An arm to which a driving force is applied by a driving source, a blade group that is sequentially pivoted with respect to the arm, and a stopper portion that contacts the blade group on the side opposite to the exposure operation direction side of the blade group are provided. It is characterized by.

The focal plane shutter for a camera according to the present invention is preferably configured to energize the electromagnetic drive source so that the blade group contacts the stopper portion before the exposure operation is started.

  Further, it is preferable that the focal plane shutter for a camera of the present invention is configured to energize the electromagnetic drive source so that the blade group comes into contact with the stopper portion in the photographing standby state.

  Furthermore, a focal plane shutter for a camera according to the present invention includes the focal plane shutter for a camera according to the present invention.

  According to the focal plane shutter for a camera of the present invention, even if the shutter blades are moved from a predetermined position in response to external impact or vibration while reducing the cost by simplifying the structure and reducing the number of parts. The exposure operation start position can be positioned, and a stable exposure operation can be performed.

The top view which shows the state before the exposure operation start of the focal plane shutter for cameras which concerns on embodiment of this invention. The side view seen from the right side of FIG. FIG. 2 is a plan view showing a state in which an exposure operation is completed from the state of FIG. 1.

Preferred embodiments of the present invention will be described with reference to the drawings.
First, the configuration of the embodiment of the present invention will be described with reference to FIGS. 1 to 3. In the description, the ground plane side will be referred to as the front side, and the auxiliary ground plane side will be referred to as the back side. The base plate 1 is formed with an opening 1a for a subject optical path at a substantially central portion thereof. Further, as is well known, the intermediate plate 2 and the auxiliary ground plate 3 shown in FIG. 2 are attached to the back side of the main plate 1 at a predetermined interval in order, and between the main plate 1 and the intermediate plate 2. The blade chamber of the front blade group 4 is formed in the front blade group 4, and the blade chamber of the rear blade group 5 is formed between the intermediate plate 2 and the auxiliary base plate 3.

  The base plate 1 has two arc-shaped long holes 1b and 1c penetrating the base plate 1 on the left side of the opening 1a. Further, as shown in FIG. 2, a leading blade stopper portion 1d and a trailing blade stopper portion 1e are formed on the back side of the base plate 1, and the leading blade stopper portion 1d is a trailing blade stopper. The height is lower than the portion 1e. Therefore, the leading blade stopper portion 1d does not affect the operation of the rear blade group 5. Furthermore, two moving magnet type motors 6 and 7 as electromagnetic drive sources are attached to the surface side of the main plate 1 by means not shown. Since the configuration of this motor is well known and described in Japanese Utility Model Publication No. 5-9709, it is not specifically shown, but rotates integrally with the permanent magnet rotors 6a and 7a. The drive pins 6b and 7b protrude through the long holes 1b and 1c to the back side.

The configuration of the leading blade group 4 and the trailing blade group 5 arranged on the back side of the main plate 1 will be described. First, the leading blade group 4 was pivotally supported in order toward the two arms 8 and 9 rotatably attached to the shafts 1f and 1g provided on the back side of the main plate 1 and toward the tip side thereof. It consists of three blades. The drive pin 6b described above is fitted in a hole formed in one arm 8. On the other hand, the rear blade group 5 includes two arms 10 and 11 which are rotatably attached to shafts 1h and 1i provided on the back side of the main plate 1, and 3 which are pivotally supported in order toward their tips. Although composed of a single blade, the drive pin 7b is fitted in the hole formed in the arm 10 in the same manner as in the case of the leading blade group 4 .

Next, the operation of this embodiment will be described. Before that, the state shown in FIG. 1 will be described first. FIG. 1 shows a state in which each blade group can start an exposure operation from above to below the opening 1a. And in this state, three blade roots leading blade group 4 covers the opening 1a by a deployed state, three blade roots of the rear curtain group 5 are superimposed, the upper opening 1a Stored in position. In addition, the rotors 6 and 7 have a permanent magnet rotor, as described in Japanese Utility Model Publication No. 5-9709, although the stator coil (not shown) is not energized. A counterclockwise rotating force is applied by a magnetic attractive force acting between a ferromagnetic member (not shown) disposed on the stator side. Therefore, a force that rotates the arms 8 and 10 counterclockwise is applied via the drive pins 6b and 7b, but the arms 9 and 10 abut against the stopper portions 1d and 1e provided on the base plate 1. Thus, this state is maintained.

In the state shown in FIG. 1, when the release button of the camera is pressed, first, the stator coils of the motors 6 and 7 are energized in the forward direction, and the rotors 6a and 7a are counterclockwise. Is applied to rotate the arms 8 and 10 in the counterclockwise direction so as to be surely brought into contact with the stopper portions 1d and 1e, respectively. Therefore, when the leading blade group 4 and the trailing blade group 5 have moved from the exposure operation start position shown in FIG. 1 due to external impact or vibration, the stator coil is energized in the forward direction. It is rotated counterclockwise until it comes into contact with the stopper portions 1d and 1e.

  Thus, since each blade group is brought into contact with each stopper portion, it is positioned at the exposure operation start position of each blade group for each photographing, so that stable exposure operation can be performed reliably. Further, since a member for positioning each blade group at the exposure operation start position is not required, the structure can be simplified and the cost can be reduced by reducing the number of parts.

Next, since the stator coil of the motor 6 is energized in the reverse direction, the rotor 6a is rotated clockwise, and the drive pin 6b rotates the arm 8 clockwise. 3 blades roots of the first blade group 4 moves downward while increasing the overlap of the mutual, will open the opening 1a. Thereafter, after a predetermined time has elapsed, the stator coil of the motor 7 is also energized in the opposite direction, so that the rotor 7a is also rotated clockwise, and the drive pin 7b causes the arm 10 to rotate clockwise. will be rotated, the three blade roots of the rear curtain group 5 moves downwards while reducing the overlap of each other, and close the opening 1a.

Thereafter, the energization in the reverse direction to the stator coils of the motors 6 and 7 is cut off, whereby the exposure operation is completed. This state is shown in FIG. Thereafter, when the stator coils of the motors 6 and 7 are energized in the forward direction from the state shown in FIG. 3, the leading blade group 4 and the trailing blade group 5 move upward and are shown in FIG. It returns to the state.

  By the way, if the motor that performs the exposure operation of each blade group increases the magnetic attraction force (holding force) for holding the exposure operation start position, the desired exposure operation characteristics can be obtained unless the motor starting force is increased accordingly. It may not be possible. For this reason, the starting current must be increased, and the power source battery of the camera will be consumed greatly. However, in this embodiment, when the release button is pressed, the stator coils of the motors 6 and 7 are energized in the forward direction, and each blade group is rotated until it comes into contact with the stopper portion. Even if the magnetic attractive force (holding force) is small, the exposure operation start position of each blade group can be surely positioned for each photographing.

In the present embodiment, the two blade groups of the leading blade group 4 and the trailing blade group 5 are provided. However, the present invention may be configured by at least one blade group. Further, in the present embodiment, the arms 9 and 10 are brought into contact with the stopper portions 1d and 1e, respectively, but the present invention may be configured such that the blades are brought into contact with the stopper portion.

  In this embodiment, a moving magnet type motor is used. However, the present invention may be a DC motor. Furthermore, in this embodiment, the energization in the forward direction to the stator coil of each motor for positioning each blade group at the exposure operation start position was performed at the time of release, but the power source of the camera body was turned on. It is possible to energize in the forward direction as appropriate even after the imaging standby state during observation of the subject.

  As described above, the focal plane shutter for cameras of the present invention can be applied to cameras such as single-lens reflex cameras and mirrorless cameras because the blade group can be reliably positioned at the exposure operation start position.

DESCRIPTION OF SYMBOLS 1 Ground plate 1a Opening part 1b, 1c Long hole 1d, 1e Stopper part 2 Intermediate | middle board 3 Auxiliary ground plate 4 Front blade group 5 Rear blade group 6, 7 Motor (electromagnetic drive source)
8, 9, 10, 11 arm

Claims (4)

A base plate and an auxiliary base plate that have an opening for a subject optical path and form a blade chamber between the two,
A blade group comprising a plurality of blades which are forward Tsugikururu支the arm and the arm is mounted et rotatably on the base plate,
An electromagnetic drive source coupled to the arm and configured to open and close the blade group with respect to the opening;
Wherein the exposure operation direction side of the blade set is provided with a stopper portion said blades on the opposite side abuts, and
A focal plane shutter for a camera , wherein the electromagnetic drive source is energized so that the blade group contacts the stopper before the blade group performs an exposure operation . 2. The focal plane shutter for a camera according to claim 1, wherein when the release button is pressed , the electromagnetic drive source is energized so that the blade group comes into contact with the stopper portion. In the shooting standby state, the camera focal plane shutter according to claim 1, wherein the blades are energized to the electromagnetic driving source so as to abut on the stopper portion.   A camera comprising the focal plane shutter for a camera according to any one of claims 1 to 3.

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