JPH10307312A - Camera shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera shutter having a simple constitution where the exposure for an object of the same luminance is not changed at every photographing. SOLUTION: Two shutter blades 4 and 5 are pivotally attached to the shaft parts 1b and 1c of a shutter base plate 1 between the shutter base plate 1 and an auxiliary base plate 2. The working pin 12a of an opening/closing member 12 which is formed integrally with the rotor 8 of a motor M is fitted in the oblong holes of the shutter blades 4 and 5, and in accordance with the forward and backward rotation of the rotor 8, the opening/closing operation is executed. In the closed state, the leading end of the shutter blade 4 comes into contact with a stopping means 1e and also a spring 13 is hung on the shutter blade 5, so that the relative position of the working pin 12a and the shutter blades is always kept in a fixed state at the time of starting photographing, even in the case any fit telerance occurs between the working pin 12a and the oblong holes of the shutter blades 4 and 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a lens shutter in which two shutter blades reciprocate relative to each other to open and close a circular exposure opening. Camera shutter.

[0002]

2. Description of the Related Art In a shutter of this type, usually, two shutters are used.
The shutter blades are pivotally attached to a shutter base plate,
The reciprocating operation is performed in conjunction with the reciprocating operation of the opening / closing member. There are two types of drive sources for the opening and closing member: one that performs both reciprocating operations with a spring force, one that performs one operation with a motor and the other with a spring, and one that performs both reciprocating operations with a motor. Further, among those in which at least one operation of the opening / closing member is driven by a motor, there is known one in which the opening / closing member is integrally formed with a rotor of the motor. Further, the connection between the two shutter blades and the opening / closing member is such that a long hole is formed in each of the shutter blades, and an operation pin of the opening / closing member is fitted to them. May be fitted into both long holes, or one provided with two actuation pins and fitted into separate long holes.

[0003] By the way, as described above, the shutter blades
It is operated by the opening / closing member, but since there is a tolerance in the fitting between the operating pin and the long hole, usually, at the time of opening the shutter, the opening operation of the opening / closing member and the opening operation of the shutter blade are always performed at a predetermined timing. It does not start, and the situation where the opening operation of the two shutter blades is not started at a predetermined timing occurs. In addition, the tolerance differs for each manufactured shutter, and the relative positional relationship between the operating pin and the long hole changes depending on how the camera is held, so that even when shooting an object scene under the same conditions, A different exposure result (cutting unevenness) will be obtained for each photographing. Therefore, conventionally, two stop means are provided on the shutter base plate, and when the shutter is closed, the operating pin presses the two shutter blades against the stop means, so that the relative positions of the three members are changed. I always wanted to maintain a certain relationship.

[0004] In recent years, some shutters that reciprocate the opening and closing member by a motor include:
A motor called a moving magnet type motor is often used. This motor is relatively small and has the advantage of low power consumption, but when the coil is not energized, the stop position of the permanent magnet rotor, that is, the stop position of the operating pin becomes unstable. There is a problem. For this reason, in this type of shutter, a magnetic member is arranged on a part of the stator, and the rotor is urged in the closing direction by magnetic attraction acting between the stator and the three-way shutter. , So that the relative position can always be maintained in a constant relationship.

[0005]

However, as described above, in order for the two shutter blades to be simultaneously in contact with the respective stopping means in the closed state, the positional accuracy of the two stopping means is required. Must be manufactured with high precision, and when the shutter base plate is made of synthetic resin, the mold is expensive, and in any case, the cost is high. On the other hand, in the case where the opening and closing operation is performed by a moving magnet type motor, a smaller magnetic member must be attached to an effective position on a small stator, which is troublesome and increases the cost. I was

Further, although the invention is different from the gist of the present invention, the relative positional relationship between the opening / closing member and the two shutter blades in the closed position can be obtained as a result. The configuration is disclosed in JP-A-8-6107. In this configuration, separate springs are applied to the two shutter blades, respectively. However, as can be determined from an embodiment of the present invention described later, the shutter blades are located within a small and narrow space. It is impossible to separately apply springs so as not to affect the operation of the shutter, and if it is attempted to make it possible, the size of the shutter blades and the outer shape of the shutter will increase. There is a problem of inviting. In addition, coil springs generally have large variations in quality, but the use of two of them increases the range of variation in the biasing force, making adjustment of the operating characteristics of the shutter blades more troublesome. There is.

The present invention has been made to solve such a problem.
Regardless of the fitting tolerance between the long hole of the shutter blade that relatively opens and closes and the operating pin of the opening and closing member, the relative position between the operating pin and the two shutter blades at the exposure operation start position Target position is always kept constant, and when shooting under the same field conditions,
It is easy to configure so that the same exposure result is always obtained.
An object of the present invention is to provide a small and low-cost camera shutter.

[0008]

In order to achieve the above-mentioned object, a camera shutter according to the present invention comprises two base plates having an opening for exposure and forming a blade chamber therebetween. And two shutter blades pivotally attached to one of the two base plates in the blade chamber and each having a long hole, and at least one operating pin fitted in the long hole. An opening / closing member that reciprocates the two shutter blades to open and close the opening when reciprocated by a drive source during exposure; And a spring that is hung on the other shutter blade and biases the shutter blade to rotate in one direction. In the camera shutter according to the present invention, preferably, the spring urges the other shutter blade in a closing direction. In the camera shutter according to the present invention, it is preferable that a driving source for an opening operation of the reciprocating operation of the opening / closing member is a motor and a driving source for a closing operation is a spring. Alternatively, the driving source for the reciprocating operation of the opening / closing member is a motor. Still preferably, the motor is a moving magnet type motor, and the opening / closing member is integrally formed with a rotor of the moving magnet type motor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to an embodiment shown in FIGS. FIG. 1 is a plan view showing a closed state of the shutter blades, and FIG. 2 is a central transverse sectional view of FIG. FIG. 3 is an explanatory plan view of the inside of the blade chamber when the shutter blades are closed, and FIG. 4 is an enlarged explanatory diagram of a main part of FIG. FIG. 5 is an explanatory plan view of the blade chamber when the shutter blades are fully opened.

First, the configuration of the embodiment will be described. The shutter base plate 1 and the auxiliary base plate 2 are both made of synthetic resin, and have a circular opening 1 for exposure that allows the field light to pass therethrough.
a, 2a are formed. Both are attached by two screws 3 from the side of the auxiliary base plate 2, and a blade chamber is formed between them. Two shutter blades 4 and 5 are arranged in the blade chamber, and are pivotally attached to shaft portions 1 b and 1 c provided on the shutter base plate 1, respectively. However, as is well known, it may be pivotally attached to the auxiliary base plate 2. Further, the shaft portion may be provided on the blade side and a hole may be formed on the main plate side. Although not shown, these ground plates 1 and 2 are provided with attachment portions to the camera body.
The camera is attached to the camera such that the shutter base plate 1 is on the lens side and the auxiliary base plate 2 is on the film side.

A motor M called a moving magnet type motor is mounted on the front side of the shutter base plate 1. This moving magnet type motor M is
As a motor used as a drive source for the shutter blades, a well-known motor is used. An upper frame 6 and a lower frame 7 made of synthetic resin support a rotor 8 of a permanent magnet, and the lower frame 7 is connected to two screws 9. , 9 attached to the shutter base plate 1.
As can be seen from FIG. 2, the coil 10 is wound so as to cover two shaft supports of the rotor 8, and outside thereof,
A cylindrical yoke 11 is mounted concentrically with the rotor 8. Then, according to the direction of the current supplied to the coil 10, the motor 8 rotates the rotor 8 in the forward direction or the reverse direction. In a normal case, the rotation is performed in the range of 30 to 40 °. Has become.

In this embodiment, the rotating shaft 8a of the rotor 8 is made of a synthetic resin, and the opening / closing member 12 is formed integrally with the rotating shaft 8a. And the opening and closing member 12
Although not shown in the figure, there is a portion that protrudes in the radial direction from the rotating shaft 8a, and further extends in a substantially right angle direction therefrom to form an operating pin 12a. This operating pin 12a
Are inserted into the blade chamber through an arc-shaped hole 1d formed in the shutter base plate 1, and elongated holes 4a, 5 formed in the shutter blades 4, 5, as is apparent from FIGS.
a. Therefore, in FIG. 1, when the rotor 8 rotates counterclockwise, the shutter blades 4, 5 open the openings 1a, 2a by the operating pin 12a, and thereafter,
When the rotor 8 rotates clockwise, the shutter blades 4, 5
Closes the openings 1a and 2a.

The shutter base plate 1 is provided with a stopping means 1e in the blade chamber. This stopping means may be provided on the auxiliary base plate 2. The tip of the shutter blade 4 can come into contact with the stopping means 1e. On the other hand, a spring 13 is hung on the shutter blade 5. The spring 13 is a coil spring, as is apparent from FIG. 2, and is wound around the shaft 2 b of the auxiliary base plate 2, one end of which is hung on the column 2 c, and the other end of which is mounted on the shutter blade 5. Three holes 5 arranged in an arc shape
b, 5b, and 5b are hung in the middle hole 5b. The spring 13 urges the shutter blade 5 in the closing operation direction, and the adjustment of the urging force is performed by selecting a position for hanging the other end from the three holes 5b, 5b, 5b.

Next, the operation of the present embodiment will be described. Before that, the closed state of the shutter shown in FIGS. 1, 3 and 4, that is, the state where the shutter blade is at the operation start position, will be described. Keep it. In this state, the coil 10 is not energized. Therefore, the rotor 8 is in an unstable state in the rotation direction. Therefore, in order to stabilize the position of the rotor 8, a magnetic member is disposed on a part of the stator of the motor M, and the closed state is maintained by the magnetic force acting between the magnetic member and the rotor 8. There are known ways to do so. However, in this embodiment, such a magnetic body is not provided.

In this embodiment, since the spring 13 urges the shutter blade 5 in the closing direction, the operating pin 12a
, The rotation of the rotor 8 in the counterclockwise direction is suppressed. At this time, the shutter blade 4 is
a is indirectly urged in the closing direction via a, and its tip is brought into contact with the stopping means 1e, thereby preventing clockwise rotation. Further, in order to effectively obtain such a state, in a stationary state in which the openings 1a and 2a are closed, the operating pin 12a is connected to the hole 1d.
And slightly spaced apart without contacting the end faces of

In this embodiment, the shutter blades 4
The shutter means 5 and the spring 13
4 in the closed state by the action of
As shown in the figure, the left side surface of the long hole 4a and the long hole 5
The right side of "a" comes into contact with the operating pin 12a. Therefore, regardless of the fitting tolerance between the operating pin 12a and the long holes 4a and 5a, the relative positional relationship between the three members is maintained constant, and vibration is applied or the camera may be held up depending on how the camera is held. This relationship has not changed.

In this configuration, even if the above-described magnetic member is provided and the rotor 8 is urged clockwise, a spring is applied to the opening / closing member 12 to rotate the rotor 8. Even if the child 8 is configured to be urged clockwise, the relative positional relationship between the three can be maintained constant. Further, in this state, it is preferable that the operating pin 12a does not contact the end surface of the hole 1d as in the present embodiment.
Even if the stop position of the operating pin 12a is regulated by the contact, the shutter blade 5
As long as the tip of the first member is surely in contact with the stopping means 1e, the relative positional relationship between the three members can be maintained constant.

When the release button of the camera is pressed in the closed state, that is, in the state of the exposure operation start position, first, the distance measuring device and the photometric circuit are operated in the initial stage. Thereafter, when a forward current is supplied to the coil 10, the rotor 8 is rotated counterclockwise, and the shutter blades 4 and 5 are opened by the operating pin 12a. At this time, as can be seen from FIG.
First, the shutter blade 5 is operated by pressing the right side surface of the long hole 5a against the urging force of the spring 13, and then the shutter blade 4 is also operated by contacting the right side surface of the long hole 4a. Will be. In the present embodiment, since the relative positional relationship between the operating pin 12a and the shutter blades 4 and 5 at the time of closing is always maintained in the same state, the shutter blade 4 is moved after the shutter blade 5 starts operating. The operation timing is always constant, and does not change for each photographing due to a posture difference or the like.

In this way, the shutter blades 4, 5
The shafts 1b, 1c relatively rotate, and the openings 1a,
Open 2a. Then, the opening operation is stopped by the operation pin 12a coming into contact with the end face of the hole 1d formed in the shutter base plate 1, and the fully opened state as shown in FIG. Immediately from this state or after a predetermined time has elapsed, the coil 10 is energized in the opposite direction. As a result, the rotor 8 rotates clockwise, so that the shutter blades 4, 5 perform an operation opposite to the above-described opening operation by the operation pin 12a, and the openings 1a, 2a.
Close.

After the openings 1a and 2a are closed, first, the tip of the shutter blade 4 comes into contact with the stopping means 1e. Thereafter, however, the operating pin 12a slightly deflects the shutter blade 4 to form the hole 1d. Contact the end face. Thereafter, when the shutter blades 4 return to the original shape due to the elasticity of the bending, all the members are brought into the state of FIG. 1 and stopped. This state is the closed state after the end of the photographing, and is also the initial state of the next photographing. As described above, this state does not change regardless of the vibration applied or the camera held in the next shooting.

In the above embodiment, the operating pin 1
The opening / closing member 12 having the opening / closing member 2a is integrally formed with the rotor 8. However, in the present invention, the opening / closing member 12 is provided separately from the rotor 8, and is rotatably attached to the shutter base plate 1. It may be configured to reciprocate by the reciprocating rotation of. Alternatively, a spring may be applied to the opening / closing member 12 so that the driving force for the opening operation is obtained from the motor, and the driving for the closing operation may be performed only by the spring. Further, the present invention can be applied to a structure in which the opening / closing member is rotatably attached to the shutter base plate 1 and both the opening operation and the closing operation are driven by a spring.

In the embodiment, the spring 13 urges the shutter blade 5 in the closing direction. However, when the spring force is used as a driving source of the closing operation as described above, or when the magnetic member is used. When biased in the closing direction using
The same effect can be obtained by weakening the spring force applied to the shutter blade 5 and biasing the shutter blade 5 in the opening direction. Further, the shutter that relatively opens and closes the two shutter blades includes a shutter in which one operating pin is fitted into a long hole of both blades as in this embodiment, and a shutter that operates by opening and closing members. There is known a type in which two pins are provided, each of which is fitted into a long hole of another blade. The present invention can be applied to such a type of shutter.

[0023]

As described above, according to the present invention, in the camera shutter for opening and closing the two shutter blades relatively, one blade is brought into contact with the stopping means in the closed state, and the other blade is brought into contact with the other blade. Adopts a very simple configuration that applies a spring that urges in the rotational direction,
Regardless of the fitting tolerance between the operating pin of the opening / closing member and the long hole of the shutter blade, the relative positional relationship between the operating pin and the two shutter blades in the closed state can always be kept constant. Therefore, in shooting with the same field brightness, it is possible to eliminate the occurrence of so-called unevenness in which different exposures are performed for each shooting.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment showing a closed state of a shutter blade.

FIG. 2 is a central cross-sectional view of FIG.

FIG. 3 is an explanatory plan view of a blade chamber in the embodiment;
3 shows a closed state of a shutter blade.

FIG. 4 is an enlarged explanatory view of a main part of FIG. 3;

FIG. 5 is an explanatory plan view of a blade chamber in the embodiment;
The fully opened state of the shutter blade is shown.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a, 2a Opening 1b, 1c, 2b Shaft 1d, 5b hole 1e Locking means 2 Auxiliary base plate 2c Column 3, 9 Screw 4, 5 Shutter blade 4a, 5a Slot M Moving magnet type motor 6 Upper frame 7 Lower frame 8 Rotor 8a Rotating shaft 10 Coil 11 Yoke 12 Opening / closing member 12a Working pin 13 Spring

Claims (5)

[Claims] 1. A base plate having an opening for exposure and forming a blade chamber between the two base plates, and an elongated hole which is pivotally connected to one of the two base plates in the blade chamber. A shutter blade having at least one operating pin fitted into the long hole, and the shutter blades are relatively moved when reciprocated by a driving source during exposure. An opening / closing member that reciprocates to open and close the opening; a stopping means provided on one of the base plates that prevents operation of one shutter blade in a closing direction when the opening is closed; A shutter which is hung on the blade and biases the shutter blade to rotate in one direction. 2. The camera shutter according to claim 1, wherein the spring urges the other shutter blade in a closing direction. 3. The camera shutter according to claim 1, wherein a driving source of the opening operation of the reciprocating operation of the opening / closing member is a motor, and a driving source of the closing operation is a spring. 4. The camera shutter according to claim 1, wherein a driving source of the reciprocating operation of the opening / closing member is a motor. 5. The camera shutter according to claim 4, wherein the motor is a moving magnet type motor, and the opening / closing member is formed integrally with a rotor of the motor.