JP5047546B2 - Focal plane shutter - Google Patents

Description

The present invention relates to a focal plane shutter for a camera.
Specifically, the present invention relates to a focal plane shutter in which a light-shielding blade and an arm are rotatably connected, and the opening and closing operation of the blade is caused by the rotation of the arm.

  Conventionally, as this type of focal plane shutter, a pair of hollow cylindrical dowels are integrally formed at one end of each blade, and the heads of these dowels are made larger in diameter than the body and arm holes, and the outer peripheral surface thereof. Is formed into a taper shape that gradually decreases in diameter toward the tip, and a plurality of slits are provided from the tip of the head to the body at predetermined intervals in the circumferential direction, and the structure can be elastically reduced in diameter, By inserting the dowel head into the hole of the arm and inserting it, the head expands elastically after insertion, and the step formed between the body and the body is engaged with the hole edge of the arm. In some cases, the blades can be rotated with respect to the arm and prevented from coming off (for example, see Patent Document 1).

Japanese Utility Model Publication No. 57-201521 (page 2-3, FIG. 3-5)

By the way, the focal plane shutter having such a structure has a blade thickness of about 0.1 mm and an arm thickness of about 0.2 mm which are currently used in general with the miniaturization of the camera. These thin blades and arms are very delicate parts that cannot be stably opened and closed by plastic deformation even with a slight external force. Yes.
However, in the conventional focal plane shutter as described in Patent Document 1, the dowel head is inserted and retained by forcibly pushing the dowel head into the hole of the arm and elastically deforming the dowel head. As the part is pushed in, an excessive force acts on the peripheral part of the hole of the arm and plastically deforms, and this plastic deformation causes a backlash between the body of the dowel and the hole of the arm. There is a fear that it cannot move.
As a result, if multiple blades are opened / closed by rotating the arm, the durability of the arms will decrease, and more wear will occur due to sliding between these blades or sliding between the body of the dowel and the hole in the arm. There was a problem that powder was generated.
Furthermore, when the exposure operation is performed by running the shutter blade composed of such blade and arm, the start position of the blade becomes unstable or the slit forming edge becomes slanted due to the rattling between the arm and the blade described above. As a result, there is a problem that uneven exposure is likely to occur.
Further, the shutter blade having such a configuration is not only that each blade travels in parallel with the rotation direction of the arm when the plurality of blades open and close by the rotation of the arm, but also a direction intersecting with the rotation direction (optical axis direction). There are various complicated movements, such as operating with irregular movement.
However, in the conventional focal plane shutter as described in Patent Document 1, the head of the dowel that can be elastically reduced in diameter is fitted into the hole of the arm to prevent it from coming off. Force in the direction of tilting the dowel head with respect to the penetration direction of the hole of the arm due to the impact of the blade and the arm rotating around the trunk and when the blade contacts the stopper at the end of travel of the blade When this occurs, there is a problem that the head of the dowel is reduced in diameter due to the inclined pressing force and comes off from the arm.
Furthermore, since the dowel of Patent Document 1 has a complicated shape in which a plurality of slits and a tapered outer peripheral surface are formed on the head, it is difficult to form the dowel itself. There is also a problem that it is very difficult to precisely mold a dowel of about 1 mm or less on the surface of a thin plate.

The invention according to claim 1 of the present invention provides a stable opening / closing operation by preventing deformation of the peripheral edge of the hole at the connecting portion between the arm and the blade, thereby improving durability and facilitating manufacture. The object is to provide a plain shutter.
In addition to the object of the invention described in claim 1, the invention described in claim 2 aims to simplify the retaining structure.

In order to achieve the above-described object, the invention according to claim 1 of the present invention is provided by integrally forming a solid boss projecting from one member of a blade and an arm, and the other member is provided with the above-mentioned object. A through hole is provided so as to be rotatable with the boss, the boss is inserted into the through hole, the tip of the boss is plastically deformed to form a retaining portion, and the blade and the arm are rotatably connected. It is characterized by.
According to a second aspect of the present invention, in the configuration of the first aspect of the present invention, one of the blades and the arm is formed of a thermoplastic material, and a solid boss protrudes on the surface facing the other side. It is characterized in that it is integrally molded, and the tip end portion of this boss is heat caulked to form a retaining portion having a larger diameter than the through hole.

According to the first aspect of the present invention, a solid boss protrudes from one of the members of the blade and the arm and is provided by integral molding, and the other member penetrates the boss so as to be rotatable. A hole is provided, the boss is inserted into the through hole, the tip of the boss is plastically deformed to form a retaining portion, and the blade and the arm are rotatably connected. Unreasonable force does not act on the peripheral edge, and the other member is sandwiched between one member of the blade and the arm and the retaining portion so as to be rotatable about the boss.
Therefore, it is possible to provide a focal plane shutter that can prevent the deformation of the peripheral portion of the hole in the connecting portion between the arm and the blade and obtain a stable opening / closing operation.
As a result, the peripheral edge of the through-hole may be plastically deformed when the boss is inserted, compared to the conventional one in which the head of the dowel is forced into the arm hole and elastically deformed by inserting it into the hole of the arm. Therefore, even if multiple blades are opened and closed by rotating the arm, the durability of the blades and arms can be improved, and the amount of wear powder generated at these sliding parts can be greatly reduced. .
Further, when the exposure operation is performed with the shutter blade having such a configuration, the start position of the blade can be stabilized, and the slit forming edge is not inclined, so that uneven exposure can be prevented.
In addition, compared to the conventional one in which a dowel head that can be elastically reduced in diameter is inserted into the hole of the arm to prevent it from coming off, each blade is opened and closed when the plurality of blades open and close by the rotation of the arm. Even if various complicated movements are performed, for example, the movement is performed irregularly in a direction crossing the rotation direction of the arm, the connection portion between the blade and the arm does not come off, and the durability is improved.
Furthermore, it is easier to manufacture even on the surface of an extremely thin plate such as a blade, and the cost is lower than the conventional one that has a complicated shape dowel with a plurality of slots and a tapered outer peripheral surface on the head. Can be planned.

In addition to the effect of the invention of claim 1, the invention of claim 2 is such that either one of the blades and the arm is formed of a thermoplastic material, and a solid boss is projected on the surface facing the other. After integrally molding and inserting the boss into the through hole, the tip of the boss protruding from the through hole is caulked to form a retaining portion having a larger diameter than the through hole.
Therefore, the retaining structure can be simplified.
As a result, it is easier to mold compared to conventional ones with complex shapes that require multiple slots and tapered outer peripheral surfaces to be formed on the head of the dowel. Since a boss of about 1 mm or less can be precisely molded on the surface, the manufacturing cost can be greatly reduced.

Hereinafter, two embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention. FIG. 1 shows a state immediately after the exposure operation of the shutter blades A and A 'is completed in the focal plane shutter of the present invention. (A) is the top view which expanded only the shutter blade | wing A partially, (b) is the longitudinal cross-sectional view which further expanded the connection part of the blade | wing 1 and the arm 2, FIG. 3 is the same as FIG. The shutter blades A and A ′ viewed in the set state are shown.
FIG. 4 shows a second embodiment of the present invention, and is a partially enlarged longitudinal sectional view of the connecting portion between the blade 1 and the arm 2.

First, the configuration of the first embodiment of the present invention will be described.
In this first embodiment, the focal plane shutter of the present invention is provided with an intermediate plate and an auxiliary ground plate (not shown for the sake of clarity) attached in order to the back side of the shutter base plate B, and these plate members. Two blade chambers are formed between them, and in these blade chambers, the shutter blade A composed of the light-shielding blade 1 and the arms 2 and 2 'is used as a leading blade, and the shutter blade A' is used as a rear blade. 1 shows a case where three pieces are individually arranged.

  In FIG. 1, the shutter base plate B is formed with an exposure opening B1 having a rectangular shape at a substantially central portion thereof, and on the left side of the opening B1, axes B2, B3, B4 and B5 are set. The mounting shaft E1 of the member E is erected, and two arc-shaped long holes B6 and B7 are opened, and the buffering member of the stopper whose planar shape is formed in a substantially C shape at the lower end thereof B8 and B9 are attached.

The shafts B2 and B3 have shafts B2 'and B3' coaxial with them on the blade chamber side, and the shafts B4 and B5 stand up toward the blade chamber side.
Further, a leading blade driving member C and a trailing blade driving member D are rotatably attached to the shafts B2 and B3, and a driving pin C1 of the leading blade driving member C passes through the elongated hole B6. The driving pin D1 of the trailing blade driving member D is connected to the driving hole 2b of the trailing blade A ′, which will be described later, through the long hole B7. ing.

  The arms 2, 2 'of the shutter blade A constituting the front blade are respectively provided with support holes 2a, 2a' rotatably fitted to the shafts B2 ', B4, and the front blade. A drive hole 2b that fits with the drive pin C1 of the drive member C is opened.

A solid boss 3 is provided on one of the connecting portions between the blade 1 of the leading blade A and the arms 2 and 2 ', and the other member is rotatable with the boss 3. the slightly larger diameter of the through-hole 4 than the boss 3 disposed as the tip of this after the boss 3 is inserted into the through-hole 4, a boss 3 protruding from the surface of the other member of the through hole 4 is formed By plastically deforming the portion to form the retaining portion 3a, the other member is sandwiched between the one member and the retaining portion 3a so as to be rotatable about the boss 3.

  One of the blade 1 and the arms 2 and 2 'is formed of a thermoplastic material such as a thermoplastic resin, and a boss 3 is projected and integrally formed on the surface facing the other side. Is inserted into the through-hole 4 provided in the other member, and then the tip of the boss 3 protruding from the through-hole 4 is subjected to heat caulking to deform its diameter to be larger than that of the through-hole 4. It is preferable to form a secure retaining portion 3a.

  In the case of the first embodiment, the blade 1 is made of a blackened thermoplastic material in the form of an extremely thin strip having a thickness of about 0.1 mm, and is formed on the surface of the arm 2, 2 'side. Each of the two bosses 3 is integrally formed, and the arms 2 and 2 'are made of a material such as SK material (cold rolled steel strip for spring) or titanium material, and a very thin strip having a thickness of about 0.2 mm. The through hole 4 is formed and the boss 3 of the blade 1 is inserted into the through hole 4 and then the tip end portion of the boss 3 is caulked to form the retaining portion 3a. .

  Further, if necessary, at least the surface of the boss 3 is appropriately plated with a material so that the surface hardness of the boss 3 is harder than the surface hardness of the through-hole 4. It is also possible to suppress the generation of wear powder due to rubbing between the outer peripheral surface of the boss 3 and the through hole 4.

On the other hand, the rear blade A ′ is arranged by turning the front blade A upside down, and the arms 2, 2 ′ have support holes 2a, 2a ′ rotatably fitted to the shafts B3 ′, B5. Each of the holes is opened, and a drive hole 2b that fits with the drive pin D1 of the rear blade drive member D is opened.
Among the blades 1 of the leading blade A and the trailing blade A ′, the blades connected on the leading ends of the arms 2 and 2 ′ are slit forming blades.

Next, the operation of this embodiment will be described.
In the stop state immediately after the exposure operation shown in FIG. 1, the leading blade driving member C is rotated clockwise by the biasing force of the leading blade driving spring (not shown), and the contact portion C3 is a buffer member of the stopper. This stop state is maintained in contact with B8, and at this time, the blade 1 of the leading blade A is superimposed and stored in a position below the opening B1.
Further, the rear blade drive member D is rotated clockwise by the urging force of the rear blade drive spring (not shown), and the abutting portion D3 comes into contact with the buffer member B9 of the stopper, and this stopped state is maintained. At this time, the blade 1 of the rear blade A ′ is unfolded and covers the opening B1.

  In the setting operation of the first embodiment, the set member E is rotated clockwise against a biasing force of a return spring (not shown) by a camera side member (not shown), and the leading blade drive is driven by the pushing portion E2. By rotating the member C counterclockwise against the urging force of the leading blade drive spring, the arm 2 of the leading blade A is rotated counterclockwise by the driving pin C1, and the three blades of the leading blade A are rotated. The blades 1 move upward while reducing mutual overlap.

  In this way, when the slit forming blade of the leading blade A overlaps with the slit forming blade of the trailing blade A ′ by a predetermined amount, the pushing portion E3 of the set member E starts the trailing blade driving member D from the trailing blade. Since the arm 2 of the rear blade A ′ is rotated counterclockwise by the drive pin D1, the three blades 1 of the rear blade A ′ are rotated. Move upwards with increasing mutual overlap.

Then, the blade 1 of the rear blade A ′ is superposed and stored in a position above the opening B1, and the blade 1 of the leading blade A is deployed to completely cover the opening B1, and the leading blade driving member C and The iron piece members C4 and D4 attached to the trailing blade driving member D are stopped when they reliably contact the leading blade electromagnet C2 and the trailing blade electromagnet D2.
FIG. 3 shows a completed state of the set operation thus performed.

  Thereafter, when the release button of the camera is pressed at the time of shooting, the leading blade electromagnet C2 and the trailing blade electromagnet D2 are energized, and the iron piece members C4 and D4 of the leading blade driving member C and the trailing blade driving member D are attracted. While being held, the set member E is rotated counterclockwise by the biasing force of the return spring as the member on the camera side returns, so that the pushing portions E2 and E3 are connected to the leading blade drive member C. It leaves | separates from the drive member D for rear blades, returns to the initial position shown in FIG. 1, and stops.

  In such a state immediately before the release, when the boss 3 is inserted into the through hole 4 when the blade 1 and the arms 2 and 2 'of the leading blade A are assembled, an excessive force acts on the peripheral edge of the through hole 4. Therefore, the start position of each blade 1 can be stabilized because the plastic deformation does not occur and no backlash occurs.

Following this, the current supply to the leading blade electromagnet C2 is first cut off, and the power supply to the trailing blade electromagnet D2 is cut off after a predetermined time.
Therefore, first, when the energization to the leading blade electromagnet C2 is cut off and the holding force is released, the leading blade driving member C is rapidly rotated clockwise by the biasing force of the leading blade driving spring. Since the arm 2 of the leading blade A is rotated in the clockwise direction by the driving pin C1, the three blades 1 of the leading blade A move downward while increasing the mutual overlap amount, and the slit forming edge (upper side) of the slit forming blade ) To open the opening B1.

  Next, when the energization to the rear blade electromagnet D2 is cut off and the holding force is released, the rear blade drive member D is rapidly rotated clockwise by the urging force of the rear blade drive spring. Since the arm 2 of the rear blade A ′ is rotated clockwise by the pin D1, the three blades 1 of the rear blade A ′ move downward while reducing the amount of mutual overlap, and the slit forming edge of the slit forming blade The opening B1 is covered with (lower side).

In this way, the exposure operation by the leading blade A and the trailing blade A ′ is continued, but the leading blade A that has started the operation first has an opening at the slit forming edge (upper side) of the slit forming blade that travels last. When the driving pin C1 of the leading blade driving member C comes into contact with the buffer member B8, the driving is stopped when the driving pin C1 retracts downward from B1.
Subsequently, in the rear blade A ′, when the slit forming edge (lower side) of the slit forming blade that travels first covers the opening B1, the drive pin D1 of the rear blade drive member D contacts the buffer member B9. Stopped by touching.

Also in this case, when the boss 3 is inserted into the through hole 4 during the assembly of the blade 1 and the arms 2 and 2 'of the shutter blade A, an excessive force acts on the peripheral edge of the through hole 4 without plastic deformation. Since there is no backlash caused by this, the slit forming edges of the leading blade A and the trailing blade A ′ are not inclined, so that uneven exposure does not occur.
The state immediately after the exposure operation is completed is the state shown in FIG. 1, and the above-described operation is repeated.

Next, the configuration of the second embodiment of the present invention will be described with reference to FIG.
In the second embodiment, as shown in FIG. 4, the arms 2 and 2 'are formed of a thermoplastic material, and three solid bosses 3 are integrally formed on the surface of the blade 1 side. 1 is made of a blackened synthetic resin material or other material in the form of an extremely thin strip, and a through hole 4 is opened so as to be rotatable with the boss 3. Unlike the first embodiment shown in FIGS. 1 to 3, the structure in which the retaining portion 3a is formed by inserting the 2,2 'boss 3 and then caulking the tip portion of the boss 3 by heat. The rest of the configuration is the same as that of the first embodiment shown in FIGS.
Therefore, the second embodiment shown in FIG. 4 can obtain the same effects as those of the first embodiment described above.

  In the embodiment shown above, either one of the blade 1 and the arms 2 and 2 'is formed of a thermoplastic material, and the boss 3 is protruded from the surface opposite to the other to be integrally formed. After inserting into the hole 4, the tip of the boss 3 protruding from the through hole 4 is caulked to form a retaining part 3 a, but the present invention is not limited to this, but the blade 1, arms 2, 2 ′ and boss 3 Can be separately molded and fixed, or the tip of the boss 3 can be plastically deformed by a method other than thermal caulking to form the retaining portion 3a.

Further, in the first embodiment, an intermediate plate and an auxiliary base plate are sequentially attached in parallel to the shutter base plate B, and two sets of shutter blades A, a front blade, a rear blade are provided in two blade chambers formed between these plate members. As an example, three blades 1 are individually arranged. However, the present invention is not limited to this. For example, a pair of shutter blades A is formed in one blade chamber formed between the shutter base plate B and the auxiliary base plate. Or the number of blades 1 may be changed to one or more.
Even if it comprises in these ways, an equivalent effect is obtained. Therefore, what was made to operate | move like that is included in this invention.

1 is an overall plan view of a focal plane shutter as viewed from the subject side according to an embodiment of the present invention, and shows a state immediately after the exposure operation of a shutter blade is completed. (A) is the top view which expanded only the shutter blade | wing for front blades partially, (b) is the longitudinal cross-sectional view which expanded the connection part of a blade | wing and an arm further partially. FIG. 3 is a plan view of the whole viewed from the subject side, showing a state where the shutter blades have been set. It is the elements on larger scale of the connection part of the blade | wing and arm of a focal plane shutter which show the other Example of this invention.

Explanation of symbols

1 blade 2, 2 'arm 3 boss 3a retaining portion 4 through hole A, A' shutter blade

Claims (2)

Two ground planes each having an opening for exposure and constituting at least one blade chamber therebetween, and a plurality of arms rotatably attached to one of the two ground planes; Opening and closing the opening on the shutter blades by reciprocatingly rotating one of the arms, and at least one pair of shutter blades each composed of at least one blade rotatably connected to the plurality of arms. In a focal plane shutter comprising at least one drive member for performing an operation,
A solid boss is projected from one member of the blade and the arm, and provided by integral molding ,
The other member is provided with a through hole so as to be rotatable with the boss,
A focal plane shutter, wherein the boss is inserted into a through hole, the tip of the boss is plastically deformed to form a retaining portion, and the blade and the arm are rotatably connected. 2. The focal plane shutter according to claim 1, wherein either one of the blades and the arm is formed of a thermoplastic material, and a tip end portion of the boss is thermally crimped to form a retaining portion having a larger diameter than the through hole.

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