JPH075131U - Shading blade device for camera - Google Patents

Abstract

(57) [Summary] [Object] To provide a light-shielding blade device for a camera using a gear mechanism, which has a degree of freedom in design and has a small frictional resistance. . [Configuration] Pins 2a, 3a, 4a of each blade 2, 3, 4
Are rotatably supported by shutter blades (not shown). Pins 5b, 5c and 5d of the link member 5 rotatably support the blades 2, 3 and 4. The tooth portion 5e of the link member 5 meshes with the pinion 7 integrated with the pulse motor 6. When the pinion 7 turns counterclockwise, the link member 5 swings to move the blades 2, 3, 4 in the opening direction, and when the pinion 7 turns counterclockwise, the blades 2, 3, 4 move in the closing direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to the structure of a shading blade device used in a camera.

[0002]

[Prior art]

 Conventionally, a gear mechanism has been known for simultaneously reciprocating a plurality of light shielding blades at respective fulcrums. They can be roughly divided into two types. The first type is one in which the teeth are directly formed on the blade itself (Japanese Utility Model Laid-Open No. 4-2025), or a gear is integrally fixed to the rotating part of the blade (Japanese Utility Model Laid-Open No. 1-153533). Gazette, Japanese Utility Model Publication No. 3-114825). The second type is one in which teeth are formed on a blade opening / closing lever or a lever which is interlocked with the blade opening / closing lever (Japanese Utility Model Laid-Open No. 3-86330 and Japanese Utility Model Laid-Open No. 3-114825).

[0003]

[Problems to be solved by the device]

 However, in the first type, the arrangement of the members that mesh with the teeth and are driven is limited, so the degree of freedom in design is low, and it is possible to drive three or more blades. Is extremely difficult. Also, the second type has a slight increase in the degree of freedom in the arrangement of the above-mentioned driving members as compared with the first type, but the shape of each lever to be interposed and the connection relationship with the blades are different. It requires some ingenuity, and it is extremely difficult to drive three or more blades as in the first type. In order to solve these problems, a drive ring connected to the moving point of each blade and arranged concentrically with the exposure opening is provided, and this drive ring is reciprocally rotated by a gear mechanism. However, there are the following problems in providing such a drive ring. That is, since the drive ring is required to always reciprocally rotate concentrically with the exposure opening, it is necessary to provide the guide portion on the base plate, but the frictional resistance generated between the guide portion and the drive ring is large. In particular, the friction of the inner diameter causes the operating efficiency of the drive ring to be extremely poor.

The present invention has been made in view of the above problems, and an object thereof is to have a roller that reciprocates a blade by using a gear mechanism, and has a degree of freedom in design. An object of the present invention is to provide a light-shielding blade device for a camera having a small frictional resistance.

[0005]

[Means for Solving the Problems]

 To achieve the above object, a light-shielding blade device for a camera of the present invention is provided with a plurality of blades having a fulcrum portion and a fulcrum portion, which reciprocally rotate at the fulcrum portion, and one side portion of an exposure opening. A gear that is reciprocally rotated by a drive source, and a link member that has a tooth portion that meshes with the gear and that is rotatably connected to each blade at the moving point portion. The line segments connecting the fulcrum part and the moving point part are substantially parallel to each other.

[0006]

[Action]

 When the gear is rotated in the forward direction by a drive source, for example, a pulse motor, the link member meshed with it swings in the diameter direction of the exposure aperture as a whole with the fulcrum of each blade as a fulcrum, and the blade is exposed. Move in the opening direction. On the contrary, when the gear is rotated in the opposite direction, the link member swings in the opposite direction and moves the blade in the closing direction of the exposure opening.

[0007]

【Example】

 An embodiment in which the blade of the present invention is applied to a shutter blade will be described with reference to FIGS. FIG. 1 shows the shutter blade closed, and FIG. 2 shows the shutter blade fully open. In the figure, 1 is a cover plate having an exposure opening 1a. Reference numerals 2, 3 and 4 denote shutter blades, and pins 2a, 3a and 4a planted therein are supported by a shutter base plate (not shown) provided on the front side of the paper surface, and fulcrum points of the respective shutter blades. It is a division. Reference numeral 5 denotes a link member formed in an annular shape so as to surround the exposure opening 1a, and has a window 5a for allowing the pin 2a of the shutter blade 2 to be supported by a shutter base plate (not shown). Further, pins 5b, 5c, 5d are planted in the link member 5 and tooth portions 5e are formed. The pins 5b, 5c and 5d are rotatably fitted in circular holes provided in the shutter blades 2, 3 and 4, and the fitting portion serves as a moving point portion of each shutter blade. Reference numeral 6 denotes a pulse motor attached to the back surface of the cover plate 1, and its output shaft 6a projects to the front surface side of the cover plate 1. Reference numeral 7 is a pinion fixed to the output shaft 6a, and meshes with the tooth portion 5e of the link member 5. The line segments connecting the pins 2a, 3a, 4a of the shutter blades and the pins 5b, 5c, 5d of the link members have substantially the same length and are configured to be substantially parallel to each other.

Next, the operation will be described. When the shutter is released, the pulse motor 6 starts in FIG. 1 and the pinion 7 turns counterclockwise. As a result, the link member 5 is moved, but its movement is a swinging movement about the pins 2a, 3a, 4a. Due to this swinging movement, the shutter blades 2, 3 and 4 rotate rightward to open the exposure opening 1a. Then, when the shutter blades 2, 3, 4 reach the positions shown in FIG. 2, the pulse motor 6 is stopped. When the pulse motor 6 is reversely rotated by a signal from the exposure time controller after a predetermined time has elapsed, the pinion 7 rotates right in FIG. Therefore, the link member 5 swings in the opposite direction to the above, the shutter blades 2, 3, 4 are rotated counterclockwise, and the exposure opening 1a is closed. When the shutter blades 2, 3, 4 reach the positions shown in FIG. 1, the pulse motor 6 stops.

In the above embodiment, the link member 5 has a ring shape surrounding the exposure opening 1a, but the link member 5 may have a shape in which the pin 5c and the pin 5d are cut off. The present invention is not limited to the shutter opening / closing mechanism as described above, but can be implemented as an aperture setting mechanism by stopping the pulse motor 6 at a predetermined aperture position.

[0010]

[Effect of device]

 As described above, according to the present invention, in the light-shielding blade device in which the blade is reciprocally moved by using the gear mechanism, the reciprocating operation of the blade is performed by the swing motion of the link member. The frictional resistance is much smaller than that using a drive ring that rotates concentrically with the opening, and the position of the teeth provided on the link member can be selectively determined around the exposure opening. It can be implemented regardless of the position of the gear that meshes with the tooth portion and without providing a special connecting member.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, showing a closed state of shutter blades.

FIG. 2 is a plan view of the same embodiment as the embodiment shown in FIG. 1, showing a fully open state of shutter blades.

[Explanation of symbols]

 1 cover plate 1a exposure opening 2,3,4 shutter blades 2a, 3a, 4a, 5b, 5c, 5d pin 5 link member 5a window 5e tooth 6 pulse motor 6a output shaft 7 pinion

Claims (4)

[Scope of utility model registration request] 1. A plurality of blades having a fulcrum portion and a moving point portion that reciprocally rotate at the fulcrum portion, a gear provided on one side of the exposure opening and reciprocally rotated by a drive source, and the gear. Each of the blades has a tooth portion that meshes with each other and a link member that is rotatably connected to the moving point portion. In the connection, line segments connecting the fulcrum portion and the moving point portion of each blade are substantially mutually. A light shielding blade device for a camera, which is configured to be parallel. 2. The light-shielding blade device for a camera according to claim 1, wherein the drive source is a pulse motor capable of forward and reverse rotations. 3. The light-shielding blade device for a camera according to claim 1, wherein the blade is a shutter blade. 4. The light-shielding blade device for a camera according to claim 1, wherein the blade is a diaphragm blade.