JP2019184889A - Camera focal plane shutter - Google Patents

Abstract

To provide a focal plane shutter that reduces a tremor of an iron piece and shortens a halt time of a drive lever.SOLUTION: A drive lever having a drive pin engaging with a hole of a blade arm is disposed in a base plate 1 in a rotatable state, a drive spring 16 is swaged in the drive lever with an iron piece shaft 13 penetrating a compression spring 14 into an iron piece 11 abutting with an iron core 8 of an electromagnet and urges spring force to the drive lever. A first buffer member 3 abutting with the drive pin and made of an impact absorption property is disposed in the base plate and a second buffer member 4 having an iron piece shaft rear surface 13b abutting with the base plate or an auxiliary base plate and made of the impact absorption property is disposed in the base plate or the auxiliary base plate. A material of the first buffer member is lower in material hardness than that of the second buffer material. In a blade travelling action serving an exposure action, the drive lever rotates by the drive spring and causes a blade group to run. Firstly the drive pin abuts with the first buffer member, and the first buffer member firstly deforms. Next, the iron piece shaft rear surface abuts with the second buffer member and the second buffer member deforms.SELECTED DRAWING: Figure 2(c)

Description

  The present invention relates to a focal plane shutter for a camera provided with one or two shutter blade units.

  Some conventional focal plane shutters use electromagnets as a method for controlling the running timing for performing an exposure operation with light-shielding blades. The blade unit is configured to be movable with a blade arm that links a plurality of blades. A drive lever unit that is driven by being engaged with a drive pin by the blade arm is disposed on the base plate in a rotatable state. The drive lever unit is disposed in a state in which the iron piece is movable. In the state before traveling of the blades that perform the exposure operation, the electromagnet is energized to attract the iron piece and hold the drive lever unit. When the energization of the electromagnet is cut at a predetermined timing, the blades travel by the force of the drive spring applied to the drive lever unit.

  For example, Patent Document 1 discloses a configuration in which an impact is absorbed by a buffer member disposed on a base plate with respect to a drive lever.

Japanese Patent No. 5573155 Japanese Patent No. 5020685

  However, in the prior art disclosed in the above-mentioned patent document, it took time until the drive lever collided with the buffer member, the iron piece continued to shake, the entire drive lever unit also shook, and the blades stopped and stabilized. .

  Therefore, there is a problem that the frame speed becomes slow because it is not possible to shift to the next operation.

  Furthermore, the iron piece receiving portion of the drive lever is broken due to the iron piece continuing to shake, causing a problem of durability. Further, the iron piece continued to sway and the entire drive lever unit shook, and the drive pin and the blade arm rubbed, causing the drive pin to be scraped and dust to be generated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a focal plane shutter for a camera that can shorten the stop time of a drive lever by reducing the swing of an iron piece.

In order to achieve the above object, the present invention includes a ground plate (1) having an opening (1a) for guiding subject light, and a plurality of blade groups (19, 20) configured to block light.
The blade group (19, 20) has a plurality of blade arms (21, 22, 23, 24) rotated by links,
The blade arms (21, 22, 23, 24) are arranged in a rotatable state on the main plate (1),
There is an electromagnet on the auxiliary base plate 2 that is indirectly attached to the base plate,
A drive lever (9, 10) having a drive pin (9b, 10b) fitted to the hole (21b, 23a) of the blade arm is disposed on the main plate (1) in a rotatable state.
The drive lever (9, 10) is crimped with an iron piece shaft (13) that is a compression spring (14) passed through an iron piece (11) that contacts the iron core (8) of the electromagnet,
The iron piece (11) is arranged in a movable state,
The drive spring (16) urges the drive lever (9, 10) with a spring force,
A first buffer member (3) made of a material that is in contact with the drive pins (9b, 10b) and has a shock absorbing property is disposed on the ground plate (1),
A second shock-absorbing member (4) made of a material having a shock-absorbing property in contact with the bottom surface (13b) of the iron piece shaft and the ground plane (1) or the auxiliary ground plane (2);
The material hardness of the first buffer member (3) is lower than that of the second buffer member (4),
In the blade travel operation that is the exposure operation, the drive lever (9, 10) is rotated by the drive spring (16) to travel the blade group blade group (19, 20), and in the above operation, the drive pin (9b, 10b) is the first one. The first dampening member (3) is first abutted, the first drying member (3) is deformed first, and then the iron piece shaft back surface (13b) is abutted with the second dampening member (4). The drying member (4) is characterized in that it is deformed.

  According to the present invention, in the blade running operation, the drive pin comes into contact with the first buffer member, the first buffer member is deformed first, and then the bottom surface of the iron piece contacts the second buffer member, Due to the deformation of the second drying member, the time until the blades stop can be shortened by reducing the shaking time of the entire drive lever unit by reducing the shaking of the iron piece. Therefore, it is possible to shift to the next operation and to provide a camera fallen shutter that improves the frame speed.

Diagram showing a part of the shutter unit in the shooting standby state Diagram showing a part of the shutter unit in the shooting standby state An exploded perspective view of a part of the shutter unit An exploded perspective view of a part of the shutter unit An exploded perspective view of a part of the shutter unit The front curtain opens and the front curtain drive pin is in contact with the first cushioning member. The front curtain opens and the front curtain drive pin is in contact with the first cushioning member. Figure where the front curtain is opened and the back of the buttock of the iron piece is in contact with the second buffer Figure where the front curtain is opened and the back of the buttock of the iron piece is in contact with the second buffer

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings 1 to 4.

  In the embodiment of the present invention, description will be made using a formal plane shutter equipped with a leading blade unit 19 and a trailing blade unit 20.

[Example 1]
In the following, a farcalprene shutter for a camera according to a first embodiment of the present invention will be described with reference to FIGS. 1 (a) to 4 (b).

  FIG. 1A and FIG. 1B are diagrams showing a part of the shutter unit in a shooting standby state according to the embodiment of the present invention. FIG. 1A is a diagram showing a part of the shutter unit viewed from the lens side (not shown). FIG. 1B is a diagram illustrating a part of the shutter unit viewed from the image sensor side (not shown). 2A and 2B are exploded perspective views of a part of the shutter unit. FIG. 2A is an exploded perspective view in which a part of the configuration of the blade chamber is disassembled. FIG. 2B is an exploded perspective view in which a part of the configuration of the drive unit is disassembled.

  The configuration of the blade chamber will be described with reference to FIGS. 1B and 2A. An opening 1 a that transmits light is formed in the base plate 1. The intermediate plate 25 is disposed on the ground plate 1 so as to have a gap in the optical axis direction with respect to the ground plate 1, and the cover plate 26 is disposed on the ground plate 1 so as to have a gap in the optical axis direction with respect to the intermediate plate 25. Has been. An opening 25a is formed in the intermediate plate 25 and an opening 26a is formed in the cover plate 26 so that light can be transmitted.

  The front-curtain blade unit 19 is configured such that a plurality of front-curtain blades 19a are operated by a front-curtain blade main arm 21, a front-curtain blade sub-arm 22, and a link mechanism. The front curtain blade arm 21 is arranged so that the hole 21a is rotatable with the shaft 1c of the base plate 1, and the front curtain blade arm 22 is configured so that the hole 22a is rotatable with the shaft 1d of the base plate 1.

  The trailing blade unit 20 has a configuration in which a plurality of trailing blades 20a are operated by a trailing blade main arm 23, a trailing blade sub-arm 24, and a link mechanism. The rear curtain blade arm 23 has a hole 23a and a shaft 1e of the base plate 1, and the rear curtain blade arm 24 has a configuration in which the hole 24a is rotatable with the shaft 1f of the base plate 1.

  The leading blade unit 19 reciprocates in the gap in the optical axis direction between the intermediate plate 25 and the cover plate 26 to expose or shield the opening 1a. The rear curtain blade unit 20 reciprocates in the gap in the optical axis direction between the base plate 1 and the intermediate plate 25 to expose or shield the opening 1a. Long holes 1g and 1h are formed in the base plate 1, and a first buffer member 3 is disposed at one end of the long holes 1g and 1h. The front curtain drive pin 9 b engages with the hole 21 b of the front curtain blade arm 21. Further, the rear curtain drive pin 10 b is engaged with the hole 23 b of the rear curtain blade arm 21.

  The configuration of the drive unit will be described with reference to FIGS. 2B and 2C. The auxiliary material base plate 2 is screwed to the base plate 1 with screws 18. A coil 5 constituting an electromagnet is wound around a bobbin 6, and a wire material of the coil 5 is soldered to a terminal 7. The bobbin 6 is screwed and fixed to the auxiliary base plate 2 with screws 18 through the iron core 8. The terminal 7 is soldered to a flexible board (not shown).

  The front curtain drive lever unit 27 is rotatable with respect to the hole 9 a of the front curtain drive lever 9 and the shaft 1 a of the main plate 1. The rear curtain drive lever unit 28 is rotatable with respect to the hole 10 a of the rear curtain drive lever 10 and the shaft 1 b of the main plate 1. The fixed end 16 a of the drive spring 16 engages with the slit 17 a of the holder 17, and the holder 17 is fixed to the auxiliary base plate 2. The movable end 16 b of the drive spring 16 contacts the rib 9 c of the front curtain drive lever 9. The spring 16 generates a spring force clockwise in FIG. 1A (showing a shutter unit viewed from the lens side not shown) with the front curtain drive unit 27 as the rotation center of the shaft 1a.

  Similarly, also in the rear curtain drive lever unit 28, the movable end 16 b of the drive spring 16 contacts the rib 10 c of the rear curtain drive lever 10. The spring 16 generates a spring force in the clockwise direction in FIG. 1A (the shutter unit viewed from the lens side (not shown)) with the rear curtain drive unit 28 as the rotation center of the shaft 1b.

  The configuration of the front curtain drive lever unit 27 will be described. The front curtain drive lever 9 is provided with a compression spring 14 between the surface 9 d and the iron piece 11.

  The iron piece shaft 13 has a flange 13a. The collar part back surface 13b is a surface which corresponds to the back side of the collar part 13a. The iron piece shaft 13 passes through the ring-shaped third buffer member 12 and the hole 9g of the front curtain drive lever 9 and the compression coil spring 14, and is fixed by crimping the tip penetrating the hole 11a of the iron piece 11.

  The iron piece 11 is biased in a direction in which the iron piece 11 is separated from the surface 9d of the front curtain drive lever 9 by the spring force of the compression coil spring 14. At this time, the ring-shaped third buffer member 12 is held in contact with the bottom surface 9 f of the front curtain drive lever 9 and the flange 13 a of the iron piece shaft 13. The convex portion 9e of the front curtain drive lever 9 serves as a guide for restricting the rotation of the iron piece 11. A roller 15 is disposed on the front curtain drive lever 9 in a rotatable state.

  A motor (not shown) rotates a cam gear (not shown) by gear connection. The cam surface of the cam gear (not shown) comes into contact with the roller 15 by the cam gear (not shown), and the front curtain drive lever unit 27 rotates counterclockwise in FIG. By winding up 16 (charging operation), the camera shifts to a set state before photographing.

  The compression coil spring 14 is for absorbing the amount of overcharge between the iron piece 11 and the iron core 8 by a cam gear (not shown) in the charging operation. The rear curtain drive lever unit 28 has the same configuration as described above.

  The second buffer member 4 is disposed in the hole 4a by being inserted into the standing wall 2a of the auxiliary base plate 2. The second buffer member 4 is disposed at a position such that the flange back surface 13b of the iron piece shaft 13 and the surface 4b of the second buffer member 4 face each other when the front curtain drive lever unit 27 rotates.

  Further, the second buffer member 4 is disposed at the same position with respect to the rear curtain lever unit 28.

  The first buffer member 3, the second buffer member 4, and the third buffer member 12 are made of an elastic material such as butyl rubber.

  The first buffer member 3 is more easily deformed than the second buffer member 4 and has a high shock absorption. That is, the first buffer member 3 has a lower hardness than the second buffer member 4.

  The operation of the shutter will be described with reference to FIGS. 1 (a), 1 (b), 3 (a), 3 (b), 4 (a), and 4 (b).

<Explanation of shooting standby state>
In FIGS. 1A and 1B, the camera is in a shooting standby state. At this time, the front-curtain drive lever unit 27 and the rear-curtain lever unit 28 are held by the cam gear (not shown) via the respective rollers 15 with the drive spring 16 being wound up. At this time, the iron piece 11 is in contact with the iron core 8 and the compression spring 14 is contracted to be held in an overcharged state.

  In the above state, the coil 5 is not energized.

<Explanation of shooting start state>
When a release button of a camera (not shown) is pressed to shift to a shooting operation, a coil 5 is energized from a circuit board (not shown) to generate electromagnetic force. The iron piece 11 is attracted to the iron core 8 by electromagnetic force.

  Next, a motor (not shown) rotates, a cam gear (not shown) rotates, and the contact between the cam gear and the roller 15 is released. Therefore, the mechanical holding of the front curtain drive lever unit 27 and the rear curtain drive lever unit 28 is released. At this time, the front curtain drive lever unit 27 and the rear curtain drive lever unit 28 cannot rotate because the iron piece 11 is attracted and held on the iron core 8 by electromagnetic force.

  In the operation of starting exposure to a photographing element (not shown) after a predetermined photographing preparation is completed, first, the energization of the coil 5 holding the front curtain drive unit 27 is cut off. Then, the front curtain drive unit 27 is rotated about the axis 1 a of the main plate 1 by the spring force of the drive spring 16. The front curtain blade arm 21 that engages with the front curtain drive pin 9 b of the front curtain drive lever 9 rotates about the axis 1 c of the main plate 1. Therefore, the leading blade unit 19 operates from the shielded state to the exposed state of the opening 1a of the base plate 1.

  The energization of the coil 5 holding and holding the rear curtain drive unit 28 is cut after a predetermined time has passed since the energization of the coil 5 holding and holding the front curtain drive unit 27 is cut. Then, the rear curtain drive unit 28 is rotated about the axis 1b of the main plate 1 by the spring force of the drive spring 16. The rear curtain blade arm 23 that engages with the rear curtain drive pin 10 b of the rear curtain drive lever 10 rotates about the axis 1 e of the main plate 1. Accordingly, the trailing blade unit 20 operates from the exposed state to the shielded state of the opening 1a of the base plate 1.

  Through the above operation, the front curtain blade unit 19 and the rear curtain unit 20 form a slit to expose an image sensor (not shown). Hereinafter, this blade traveling operation for exposure is referred to as main traveling.

<Explanation of the running state>
FIG. 3A and FIG. 3B are diagrams in which the front curtain opens and the front curtain drive pin is in contact with the first buffer member. FIG. 3A is a diagram showing a part of the shutter unit viewed from the lens side (not shown). FIG. 3B is a diagram illustrating a part of the shutter unit viewed from the image sensor side (not shown).

  4 (a) and 4 (b) are diagrams in which the front curtain is opened and the back surface of the collar portion of the iron piece is in contact with the second buffering agent. FIG. 4A is a diagram illustrating a part of the shutter unit viewed from the lens side (not shown). FIG. 4B is a diagram illustrating a part of the shutter unit viewed from the image sensor side (not shown).

  The front curtain blade unit 19 operates from the shielding state to the exposed state of the opening 1a of the base plate 1, and the front curtain drive pin 9b contacts the C-shaped groove 3a of the first buffer member 3, One buffer member 3 is deformed.

  At this time, the iron piece 11 is in a state where the iron piece 11 is separated from the surface 9 d of the front curtain drive lever 9 by the spring force of the compression coil spring 14. When the first buffer member 3 is further deformed by the front curtain drive pin 9b, the iron shaft 13b is then brought into contact with the surface 4b of the second buffer member 4 and the second buffer member 4 is deformed. Absorb the shock.

  At this time, the second buffer member 4 is deformed such that the flange back surface 13b of the iron piece shaft 13 is crushed in the entry direction and further spreads in the direction of the arrow A. Thus, the contact between the flange back surface 13b of the iron piece shaft 13 and the surface 4b of the second buffer member 4 makes contact with the convex portion 9e of the front curtain drive lever 9 where the iron piece 11 serves as a guide as much as possible. It can be eliminated.

  Therefore, it is possible to prevent the iron piece 11 from scraping the convex portion 9e of the front curtain drive lever 9 and taking out dust. Also in this case, the iron piece 11 is in a state where the iron piece 11 is separated from the surface 9 d of the front curtain drive lever 9 by the spring force of the compression coil spring 14.

  In other words, it is possible to adopt a configuration in which the iron piece 11 does not come into contact with the surface 9d of the front curtain drive lever 9 by this traveling.

  As described above, since the first buffer member 3 has a lower hardness than the second buffer member 4, the first buffer member 3 is not moved by the first buffer member 3 with respect to the front curtain drive lever unit 27 during the main traveling. When the weak brake is applied, the braking force gradually increases as the first buffer member is crushed, and finally the large brake is applied when the hard second buffer member is crushed.

  Accordingly, it is possible to reduce the time until the leading curtain drive lever unit 27 stops by reducing the shaking of the iron core 11.

  In addition, since the brake is applied as described above, the number of times the front curtain drive lever unit 27 bounces after the main travel is reduced, so the number of times the front curtain drive pin 9b and the end face of the hole 21b of the front curtain blade arm 21 rub are also rubbed. Since it can be reduced, it is possible to suppress the scraping of the leading curtain drive pin 9b.

  Therefore, durability can be improved and generation of dust can be suppressed.

In the above description, the front curtain is used for explanation, but a similar configuration can be used for the rear curtain.
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

1: Base plate 1a: Opening 2: Auxiliary base plate 3: First buffer member 4: Second buffer member 5: Coil 8: Iron core 9: Front curtain drive lever 9b: Drive pin 10: Rear curtain drive lever 10b: Drive Pin 11: Iron piece 13: Iron shaft 14: Compression spring 16: Drive spring 19: Front curtain blade unit 20: Rear curtain blade unit 21: Front curtain blade main arm 22: Front curtain blade subarm 23: Rear curtain blade main arm 24 : Rear curtain blade secondary arm

Claims (2)

Having a ground plane (1) having an opening (1a) for guiding subject light and having a plurality of blade groups (19, 20) for shielding light;
The blade group (19, 20) has a plurality of blade arms (21, 22, 23, 24) rotated by links,
The blade arms (21, 22, 23, 24) are arranged in a rotatable state on the main plate (1),
There is an electromagnet on the auxiliary base plate 2 that is indirectly attached to the base plate,
A drive lever (9, 10) having a drive pin (9b, 10b) fitted to the hole (21b, 23a) of the blade arm is disposed on the main plate (1) in a rotatable state.
The drive lever (9, 10) is crimped with an iron piece shaft (13) that is a compression spring (14) passed through an iron piece (11) that contacts the iron core (8) of the electromagnet,
The iron piece (11) is arranged in a movable state,
The drive spring (16) urges the drive lever (9, 10) with a spring force,
A first buffer member (3) made of a material that is in contact with the drive pins (9b, 10b) and has a shock absorbing property is disposed on the ground plate (1),
A second shock-absorbing member (4) made of a material having a shock-absorbing property in contact with the bottom surface (13b) of the iron piece shaft and the ground plane (1) or the auxiliary ground plane (2);
The material hardness of the first buffer member (3) is lower than that of the second buffer member (4),
In the blade travel operation that is the exposure operation, the drive lever (9, 10) is rotated by the drive spring (16) to travel the blade group blade group (19, 20), and in the above operation, the drive pin (9b, 10b) is the first one. The first dampening member (3) is first abutted, the first drying member (3) is deformed first, and then the iron piece shaft back surface (13b) is abutted with the second dampening member (4). Farcalprene shutter for a camera, wherein the drying member (4) is deformed A farprene shutter for a camera, wherein the flat portion of the iron piece shaft back surface (13b) and the second buffer member (4) are in contact with each other on the flat surface (4b).