JPH0229722A - Focal-plane shutter - Google Patents

Abstract

PURPOSE:To simplify the constitution of a focal-plane shutter and to facilitate the assembly of it by forming a base plane of plastics and providing a shaft which supports a blade group so that it can freely rock and a second locking projection which locks the tip part of a blade receiving plane on the base plane. CONSTITUTION:When the focal-plane shutter is assembled, the shaft hole 21 of the blade group 2 is engaged with the shaft 11 of the base plane 1 at first and simultaneously a driving shaft which passes through a transmitting hole 17a and projects is coupled with a coupling hole 22. Next, a spacer 4 is fitted by engaging a hole 41 with the shaft 11. When the blade receiving plane 5 is coupled, a locking part 52 is advanced by sliding on the inclined surface 13a of a guide projection 13 at first and the trailing edge part of a notching part 54 is locked to the second locking projection 14 by engaging a hole 53 with the guide projection 13. Thus, the blade receiving plane 5 protects the blade groups 2 and 3 and it is coupled to the base plane 1. In such a way, the assembly of the focal-plane shutter can be facilitated and the manufacturing cost thereof can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a focal brain shutter for a camera.

[Prior Art] This type of shutter has conventionally consisted of a blade group, a mechanical body serving as a driving part thereof, and a base plate supporting the mechanical body.

It consists of a blade plate that protects the blades. The base plate is usually formed by punching out a metal material such as brass or aluminum alloy plate by press working. The surface is coated with black paint to prevent light reflection, and part of this black paint is scraped away to expose the ground. Further, the support shaft for the blade group and the shaft for connecting the blade receiving plate and the base plate are connected to the base plate by caulking.

[Problems to be Solved] In the above-mentioned conventional technology, many steps are required to form the base plate, so processing is time-consuming, and it is also time-consuming to attach the blade group and connect the blade receiving plate. The cost will be high.

Furthermore, since the shaft is caulked, dimensional accuracy is poor and productivity is poor.

An object of the present invention is to simplify the configuration of a focal brain shutter, facilitate assembly, and reduce manufacturing costs.

Another object of the present invention is to increase the rigidity of the base plate and obtain sufficient reliability and durability when the focal brain shutter is made of plastic.

[Means to solve the problem]

In order to achieve the above object, the focal brain shutter of the present invention includes a base plate having an opening, a pair of blade groups for opening and closing the opening, and a blade receiving plate for protecting the blade group. is made of plastic, and includes a shaft that swingably supports the blade group on this base plate, a first locking protrusion that locks the tip of the blade receiving plate, and a shaft that is close to the first locking protrusion. a guide protrusion having an inclined surface that guides the tip of the blade support plate upward to a position where the blade support plate is positioned; and a second guide projection that locks the rear end of the blade support plate.
A locking protrusion and a locking protrusion are integrally formed.

In addition, the blade receiving plate has a locking part that slides on the inclined surface at the tip, moves forward, climbs over the guide projection, and then is pushed down and locks with the first locking projection, and a locking part that fits into the guide projection. A hole through which the second locking protrusion can pass through the rear end, and a notch through which the rear end edge can be locked with the second locking protrusion by advancing the blade receiving plate. be.

A conductive plastic containing carbon is used as the plastic forming the base plate.

[Example code] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the base plate 1 is molded using plastic, and conductive plastic containing carbon as conductive powder is used. The carbon content is preferably 12 to 30% for reasons described later. This provides the necessary rigidity, prevents light reflection, and prevents static electricity. The base plate 1 has an opening 10, a shaft 11 that swingably supports a blade group 2.3 (described later) that opens and closes the opening 10, and a first shaft 11 that locks the tip of a blade receiving plate 5 (described later). A locking projection 12, a guide projection 13 having an inclined surface 13a that guides the blade receiving plate 5 in proximity to the locking projection 12, and a second locking projection that locks the rear end of the blade receiving plate 5. 14 are integrally formed. Further, a receiving surface 15a that receives the blade receiving plate 5 in the vertical direction, a receiving surface 15b that receives the blade receiving plate 5 in the horizontal direction, and a blade holding surface 16 that prevents the tips of the blade groups 2 and 3 from opening as shown in Figure 2.3. A slope 16a that prevents the blade group 2 from colliding with each other during travel is integrally formed continuously with the blade holding surface 16. A through hole 17a having an arcuate shape.

17b is formed such that shafts (not shown) that drive the blade groups 2.3 respectively protrude from and pass through the machine body and are movable. Further, 18 is a screw hole for attaching the shutter unit to the camera body, and 19 is a column for attaching the mechanical body.

The pair of blade groups 2 and 3 are connected such that a plurality of light shielding thin plates are moved in parallel by a lever 23 or a lever 33 to open and close the opening 10. 2
2 and 32 are connecting holes to which the tips of the drive shafts from the machine body are connected, and 21 and 31 are shaft holes that fit into the shaft 11 of the base plate 1 and are swingably supported.

A spacer 4 is interposed between the blade groups 2 and 3 so as not to impede parallel movement between the two. Spacer 4 has
A hole 41 is provided at a position facing the opening 10 and is positioned by fitting into the opening 40 and the shaft 11. Also, feather group 3
A spacer 6 is interposed between the tip of the blade and the blade receiving plate 5,
The movement of the blade group 3 is not obstructed. Spacer 6
A hole 63 is provided in which the guide protrusion 13 is fitted and positioned.

The blade receiving plate 5 has an opening 50 at a position facing the opening 10 and a shaft hole 51 at a position facing the shaft 11. A locking portion 52 that locks onto the first locking projection 12 of the base plate 1 is provided at the tip, and a hole 53 into which the guide projection 13 can fit is provided at a position close to the locking portion 52. It is. Further, the rear end portion is provided with a notch portion 54 whose rear edge portion can be locked to the second locking protrusion 14 as the blade receiving plate 5 moves forward. Also, a positioning surface 55a contacts the receiving surface 15a of the base plate 1 for vertical positioning, and a positioning surface 55b contacts the receiving surface 15b for horizontal positioning.
is the provision.

When assembling, first insert the shaft hole 2 of the blade group 2 into the shaft 11 of the base plate 1.
1 is fitted, and the drive shaft protruding through the through hole 17a is connected to the connecting hole 22. Next, spacer 4
is attached by fitting the hole 41 and the shaft 11. Place the blade group 3 on the spacer 4, and insert the shaft hole 31 into the shaft 1.
1 and connects the drive shaft protruding through the through hole 17b to the connecting hole 32. Next, spacer 6
is attached by fitting the hole 63 and the guide protrusion 13, and finally the blade receiving plate 5 is connected to the base plate 1.

When connecting the blade receiving plate 5, first, as shown in FIG.
As you slide 3a and move it forward (move to the right),
As shown in Figure 4B, the locking protrusion 14 is positioned in the notch 54. In this position, the rear end edge of the notch 54 is not yet engaged with the locking projection 14, but the locking portion 52 has climbed over the guide projection 13. Then, when the blade receiving plate 5 is continuously advanced while pushing down the locking part 52, the hole 53 fits into the guide protrusion 13 as shown in Figure 4C, and the blade receiving plate 5 returns to its original shape by its own elasticity. After returning, the locking portion 52 locks with the first locking projection 12, and the notch portion 54 locks with the second locking projection 14 at its rear end edge. Thereby, the blade receiving plate 5 is connected to the base plate 1 while protecting the blade group 2.3.

When the blade receiving plate 5 is connected to the base plate 1 in this way, unless the blade receiving plate 5 is deformed as described above, the blade receiving plate 5
does not come off from the base plate 1, so there is no need for screws or retaining rings when connecting.

Reference numeral 56 denotes a concave portion that projects downward to press the spacers 4 and 6 to prevent the blade groups 2 and 3 from wobbling.

The blade groups 2 and 3 located between the base plate 1 and the blade receiving plate 5 are
Since the blade moves in parallel while being pressed from above and below by the blade holding surface 16, the slope 16a, and the bottom surface of the four parts 56, the tip of the blade may rise or the blade may bend, resulting in a gap larger than the predetermined slit. will not occur.

Figure 5 is a graph showing the relationship between carbon content and conductivity in conductive plastics containing carbon C. It shows how properties such as rigidity, moldability, and conductivity change depending on the carbon content. It shows. Normally, plastics have low rigidity, but by containing 10% or more of carbon, the required rigidity can be obtained. However, the base plate 1
The plate thickness is as thin as 0.7m+o~1mm, and the formability is poor.
If carbon is contained in an amount of 30% or more, a problem will arise in moldability, so it is desirable that the carbon content is 30% or less. Regarding conductivity, the width of the plastic is 3cm.
When 500V is applied to m, the resistance value is 50M
Ω or less is required.

In order to meet this requirement, it is necessary to contain 12% or more of carbon. Rigid in this way.

When considering conductivity and formability, the carbon content is 1
2 to 30% is appropriate.

In this embodiment, plastic containing carbon is used for the base plate 1 in consideration of rigidity, conductivity, and moldability.
The present invention is not limited to this, but high rigidity can also be obtained by incorporating glass fibers other than carbon, glass beads, ceramic short fibers, etc., or by outsert molding a thin metal plate. Further, conductivity can also be obtained by forming metal on the base sheet metal and the body by plating, vapor deposition, etc.

[Effects] As explained above, in the present invention, since the base plate is made of plastic, it is easy to mold, and the shaft, locking protrusion, guide protrusion, etc. can be integrally molded, so these can be caulked. This eliminates the need for a joining process, which simplifies the production process and makes it possible to reduce weight.

Integral molding improves the positional accuracy of shafts, etc., making it possible to increase reliability. Since the blade receiving plate is connected to the base plate by locking the blade receiving plate to the locking protrusion or the guide protrusion, the connecting operation is simple and costs can be reduced.

By molding the base plate from carbon-containing conductive plastic, it is possible to secure the required sliding properties without using solid lubricants as in conventional methods, and to obtain sufficient rigidity, ensuring sufficient reliability and durability. You can get sex.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is an exploded perspective view, FIG. 2 is an enlarged perspective view of one blade group attached to a base plate, and FIG. 3 is an attached state of the blade group. Figures 4A to 4C are explanatory diagrams showing enlarged main parts of the step of connecting the blade receiving plate to the base plate, and Figure 5 is the carbon content when carbon is included in plastic. FIG. 1. Base plate, 10 Opening, 11 Axis, 12 First locking projection, 13 Guide projection, 13a Slanted surface, 14 Second locking Stopping protrusion, 2.3..Blade group, 5...blade receiving plate, 52..locking portion, 53..hole, 54..notch. that's all

Claims (1)

[Claims] 1. A focal plane shutter comprising a base plate having an opening, a pair of blades for opening and closing the opening, and a blade receiving plate for protecting the blade group, wherein the base plate is made of plastic. a shaft that swingably supports the blade group; a first locking protrusion that locks the tip of the blade receiving plate; and a shaft located close to the first locking protrusion. a guide protrusion having an inclined surface that guides the tip of the blade support plate upward; and a second guide protrusion that locks the rear end of the blade support plate.
A locking protrusion is formed integrally with the blade receiving plate, and the blade receiving plate has a tip that slides on the inclined surface at the tip, moves forward, overcomes the guide protrusion, and then is pushed down to the first position. a locking part that locks with the locking protrusion, a hole that can be fitted into the guide protrusion, and a rear end portion through which the second locking protrusion can pass, and the rear end edge of the second locking protrusion that locks with the locking protrusion. A focal plane shutter characterized in that the second locking protrusion is provided with a lockable notch. 2. Claim 1, wherein the plastic forming the base plate is a conductive plastic containing carbon.
Focal plane shutter as described.