JPS63174023A - Device for braking shutter - Google Patents

Abstract

PURPOSE:To prevent a trailing curtain from bending by increasing initial braking for a shutter leading curtain and increasing braking force gradually from small initial braking for the trailing curtains. CONSTITUTION:When a leading curtain driving lever 9 is released from being locked by a hook part 9c, it is rotated clockwise by a spring 11 to put a leading curtain group 3 in opening operation. Then, a trailing curtain driving lever 10 is released from being locked by a hook part 10b to places a trailing curtain group in closing operation by a spring 12. When a curtain run almost comes to the end, the lever 9 abuts on a leading brake lever 16 by a pin 9a and is reduced in speed by friction and elasticity. Then the pin 9a of the lever 9 abuts on the arm part 25a of a leading brake lever 16, so that tapered parts 25b and 25c receive braking force gradually by leaf springs 26a-26c and are reduced in speed. Then the lever 9 stops by abutting on stopper rubber 24 and then the lever 10 stops the abutting on stopper rubber 29. Consequently, the braking force is made various to prevent the trailing curtain from flexing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a brake device for a shutter that brakes the shutter blade almost at the end of its travel.

[Prior art]

Due to the desire to expand the photographic area of recent cameras, the maximum shutter speed has been improved to 174,000 seconds and the X-tuning speed to 1/250 seconds. To achieve this, the running speed of the shutter blade has been increased, the shutter blade itself has been made 1uffi, and the driving spring force of the blade has been strengthened.

Due to weight reduction, the absolute strength of the blade itself has decreased, but despite this, the blade must receive a large driving force to move. Particularly at the end of travel, when the blade travels at its maximum speed, the blade is rapidly braked with a short stroke and stopped at a predetermined position. Therefore, a tremendous force is applied to the feathers.

Therefore, the durability of the blade is greatly influenced by the braking effect at the end of this run.

For example, in the conventional type of brake that obtains braking by friction, the braking force peaks at the beginning of the brake movement. Therefore, in the rear blade, when the brake starts to move, the slit forming end of the slit forming blade is still near the end inside the shirt starter opening, so the blade is deflected by the impact of sudden deceleration due to braking, and the blade itself is Problems such as collision with the opening end and damage were likely to occur. Additionally, if braking is started after the rear blades have passed the shaft opening end, damage to the blades due to collision can be largely prevented, but the braking stroke will be extremely small, so a sufficient braking effect will not be obtained.
It had the disadvantage of reduced durability.

Therefore, the applicant's proposed Utility Model Application No. 60-68523
``It has a first and second brake lever, and the first half of the braking stroke is braked with a relatively weak force by the first lever, and the second half (after the slit-forming blade passes the shaft opening end).
works in conjunction with the second lever to apply strong braking force. ' has been filed.

However, since the braking force inevitably fluctuates in two stages, the peak of the braking force appears at the beginning of the first stage and the second stage's effectiveness, which does not result in smooth braking and still has a negative impact on the durability of the blades. was giving. Also, although it was possible to modify the braking force characteristic curve by changing the engagement timing of the first and second brake levers and by changing the pressure between the brake lever and the friction sheet using a spring, the degree of freedom in doing so was by no means limited. Thick (there wasn't.

Therefore, the present applicant also proposed in Utility Model Application No. 60-70832,
In order to continuously increase the braking force according to the amount of brake lever operation, we proposed a ``brake device with a structure in which a friction member is provided at an angle, and the brake lever that receives pressure operates along the friction member.''

As a result, the initial braking of the trailing blades is small and the braking force gradually increases (as a result, the above-mentioned problem of the trailing blades bending and colliding with the shaft opening end can be solved. Regarding braking of the leading blades, each blade is already in a state of almost overlapping each other at the beginning of the brake movement, so there is a problem in that sufficient braking is often not possible due to inertia.

[Purpose of the invention]

The present invention has been made in order to solve the above-mentioned conventional problems, and includes a leading blade brake mechanism that provides large initial braking for the leading shutter blade, while providing a small initial braking for the trailing shutter blade. The shutter brake device is characterized by a rear blade brake mechanism that gradually increases the braking force, thereby ensuring reliable braking of the leading blade and preventing deflection of the rear blade at the initial stage of braking. The purpose is to provide brake equipment.

〔Example〕

1 to 1O show examples of the present invention, where l is a shutter base plate, and an opening 1a is provided in the planar center shaft.

Reference numeral 2 denotes a cover plate that is attached opposite to the shutter base plate l so as to maintain a constant gap, and has an opening (not shown) at a position corresponding to the opening 1a. A leading blade group 3 and a trailing blade group 4 are provided between the shutter base plate l and the cover plate, and are configured to open and close the opening by operating blade arms 5 and 6 and a known link mechanism. .

7.8 is a blade dowel for rotatably connecting the blade and the blade arm.

A leading blade drive lever 9 is connected to the leading blade arm 5 through a pin 9a, and opens and closes the leading blade group 3 by rotating around an axis P. Reference numeral 9b is a hook portion for being locked in the traveling preparation position by a tip tensioning lever (not shown).

10 is a rear blade drive lever, which connects the rear blade arm 6 and pin lO.
The rear blade group 4 is opened and closed by rotating around the axis Q. Reference numeral 10b is a hook portion for being locked in the travel preparation position by a rear tension lever (not shown).

11 and 12 are optical drive springs and rear drive springs, which move the movable arm 1.
1a, 12a first, rear drive lever vertical bent portions 9C, I
The levers are brought into contact with the OC, and a biasing force is applied to rotate the front and rear drive levers clockwise around their respective rotation centers. This biasing force causes each blade group to perform a traveling motion. Note that llb and 12b are fixed arms of each drive spring, which are adjusted and held by an adjustment mechanism (not shown) so that a predetermined biasing force is generated.

13 and 14 are the first charge roller and the second charge roller,
Shafts 9d and 10 installed in the front and rear drive levers, respectively.
It is rotatably held around d.

Reference numeral 15 denotes a charge lever which is rotatable around an axis R. The arm 15a receives a force from a charge mechanism (not shown), rotates clockwise around the axis R, and the cam part 15b,
15c, push the roller 13 on the light drive lever and the roller 14 on the rear drive lever, respectively, to move each drive lever to the drive spring 1.
1. By rotating counterclockwise against the force of 12, the leading blade group and the trailing blade group are set to the traveling preparation position.

Reference numeral 16 denotes a front brake lever, which can be rotated around the shaft 8 with frictional resistance. The tip brake lever 16 has an arm portion 16a that comes into contact with the pin 9a of the tip blade drive lever and receives kinetic energy when the tip blade system travels.

The arm portion 16b receives a buffering effect from the stopper rubber 24 when the leading blade travel is completed, and the vertically bent portion 1 contacts the stopper rubber.
6c, it has a vertically bent portion 16d which receives the force of the spring 23 which acts as an auxiliary braking force when the brake is activated and acts as a returning force for the first brake lever when charging.

Reference numeral 17 denotes a front brake main plate, which has a front brake shaft S, a vertical bend 17a that holds the fixed arm of the spring 23, a vertical bend 17b that regulates the maximum setting position of the front brake lever, and a shaft 17c that holds the stopper rubber 24. ing.

18 is a brake seat that comes into contact with the front brake lever to generate frictional force.

19 is a fixed plate that is used to stabilize the friction between the brake seat and the brake lever.

A collar 20 transmits the pressing force of the leaf spring 21 to the friction surface between the first brake lever and the brake seat, and uses its outer periphery as a guide rod for the spring 23.

21 is a brake leaf spring, and by changing the pressing force,
Brake force can be adjusted.

Reference numeral 22 denotes a presser screw that presses the brake leaf spring from above so as to elastically deform it (see Fig. 4).

Reference numeral 25 denotes a rear brake lever, which is pressed against the shutter base plate from above by a leaf spring 26, and is rotatable around the shaft 1 with resistance due to the biasing force and frictional force generated by the displacement of the leaf spring. Reference numeral 25a denotes an arm portion that comes into contact with the pin 10a of the rear drive lever and receives the kinetic energy of the rear blade system during travel. 2
5b is a leaf spring arm 26a when the rear brake lever is activated;
A part of the taper that slips between 26b and the shutter base plate.

25c is a tapered portion pressed by the arm portion 26c of the leaf spring. 25d is an arm that receives a buffering effect from the stopper rubber 29 when the rear blade travel is completed. 25e is a constricted part provided with ζ4 so that the arm 25d can easily bend.

Reference numerals 27 and 28 denote hisses for fixing the leaf spring 26 to the shutter base plate, and the stopper rubber 29 is a shaft 30 implanted in the shutter base plate.
It is provided on the outer periphery of the brake lever and serves as a buffer stopper for the rear brake lever.

Next, the operation of the embodiment configured as described above will be explained.

FIG. 1 shows a state in which the shutter is ready for travel.

In the figure, when an operation start signal is applied to the leading blade control magnet among the shirt shutter speed control magnets (not shown), the magnet moves the leading blade drive lever 9 (not shown) to the hook portion 9b. (locked with the leading blade drive lever 9) to release the lock with the leading blade drive lever 9. Then, the leading blade drive lever 9 is rotated clockwise around the axis P by the biasing force of the optically driven spring 11, causing the leading blade group 3 to perform an opening operation. Thereafter, when a predetermined period of time has elapsed and an operation start signal is applied to the rear blade control magnet (not shown), the magnet is activated by the rear tension lever (not shown) (rear blade drive lever l).
(locked by the hook lOb) to release the lock from the rear blade drive lever 10. Then, the rear blade drive lever 10 is moved toward the axis Q by the biasing force of the rear drive spring 12.
The rear blade group 4 is rotated clockwise around the rear blade group 4 to perform a closing operation. Eventually, as shown in FIG. 5, when the end of the blade travel approaches, the leading blade drive lever 9 contacts the leading brake lever 16 with the pin 9a, rotates the leading brake lever counterclockwise around the axis S, and The leading blade group 3 is decelerated by receiving a braking force due to the frictional force between the brake lever 16 and the brake seat 18 and the elastic force due to the displacement of the spring 23. Subsequently, the rear blade drive lever 10 begins to contact the arm portion 25a of the rear brake lever 25 with the pin 10a. The relationship between the rear brake lever 25 and the leaf spring 26 at this time is shown in cross-sectional views in Fig. 2 (cross-section AI-AI) and Fig. 3 (cross-section Bl-B).
l).

In both figures, the tapered part 25b of the rear brake lever,
25c is pressed toward the shutter base plate 1 by a relatively weak pressing force of the arm portions 26a, 26b, and 26c of the leaf springs in the initial displacement state. As shown in FIG. 6, as the blade travel approaches the end, the leading blade group 3 continues to be decelerated by the leading brake.

The rear blade drive lever 10 rotates the rear brake lever 25 clockwise around the axis Q and receives a braking force due to the frictional force between the rear brake lever 25, the leaf spring 26, and the base plate generated by the pressing force of the leaf spring 26. The rear blade group 4 is decelerated. The relationship between the rear brake lever 25 and the leaf spring 26 at this time is shown in cross-sectional views in FIG. 7 (cross section Al-A2) and FIG. 8 (cross section B2-B2). In both figures, the tapered portions 25b, 25c of the rear brake lever actuate the arm portions 26a, 26b, and 26c of the leaf spring, respectively, to an intermediate displacement state, and the pressing force is greater than that shown in FIGS. 2 and 3 described above. It is pressed toward the shutter base plate l side by the pressing force.

As shown in FIG. 9, when the blade travel is almost completed, the leading blade drive lever 9 is moved to the vertically bent portion 1 of the leading brake lever 16.
6c comes into contact with the shock absorbing stopper rubber 24 to come to a stopped state, and at the same time the leading blade group 3 completes its travel. Subsequently, the rear blade drive lever 10 brings the arm 25d of the rear brake lever 25 into contact with the shock absorbing stopper rubber 29 to come to a stopped state, and at the same time, the rear blade group 4 completes its travel. The relationship between the rear brake lever 25 and the leaf spring 26 at this time is shown in cross-sectional views in Figure 1O (cross section A3-A3) and Figure 11 (cross section B5-
83). In both figures, the tapered portion 25b of the rear brake lever.

25c are leaf spring arm portions 26a, 26b and 2, respectively.
6c is operated to the final displacement state, and is pressed toward the shutter base plate l side with a pressing force that is even greater than the pressing force shown in FIGS. 7 and 8 described above.

As mentioned above, FIG. 13 shows the braking force applied to the pin 10a of the rear drive lever 1O from the start to the end of the brake operation in relation to the brake stroke.

There is no noticeable peak at the beginning of the braking force as shown in the braking force curve examples E, F, and G, and the braking force curve is continuous and smooth. In addition, by changing the biasing force of the leaf spring 26 and the slope of the taper part of the brake lever in contact with the leaf spring, it is possible to apply linear braking force as shown in E, or
The effect is weak at the beginning and strong at the end, as in
It is also easy to apply braking force that is relatively strong at the beginning and weak at the end.

In this embodiment, the braking force is set according to the braking force curve F.

Next, the reason why the brake for the trailing blade is provided with the brake described above, which is different from the brake for the leading blade, will be explained. FIG. 14 is a partial cutaway diagram that makes it easier to see the position of the blade at the end of the blade travel. In the figure, reference numeral 32 denotes a cover plate support that supports the shutter base plate I and the cover plate 2 at a constant interval, and also serves as a holding shaft for the blade arm stopper rubber 31. The stopper rubber 31 receives the end surface of the leading blade arm 5 on its outer peripheral surface and buffers the leading blade group. 33 is the blade stopper rubber,
A portion 33a indicated by a broken line receives the tip side of the leading blade group 3, and an upper surface 33b receives the tip side of the slit forming blade 4a of the rear blade. Therefore, the leading blade group 3 transfers the kinetic energy at the time of completion of travel to the leading blade brake and the blade arm stopper rubber 31.
．． In addition, the blade stopper rubber 33a has a good balance due to the braking and buffering components at three locations, and the blades themselves are folded and all the blades are overlapped and bundled and buffered by the blade stopper rubber.

Therefore, the durability of the blade can be maintained relatively without strengthening the leading blade brake. However, the leading blade group 3 has a correspondingly large inertia and unless the initial braking is increased, it will hit the stopper with a strong force and will not move, so it is necessary to increase the initial braking. On the other hand, the rear blade group 4 is in an expanded state when the travel is completed, and only the slit-forming blade 4a on the blade tip side is cushioned from overrun by the blade stopper rubber 33b.

Therefore, the trailing blade group 4 must absorb almost all of its kinetic energy by the trailing blade brake, and if the trailing blade brake becomes even slightly defective, the durability of the trailing blade group immediately deteriorates. Therefore, the conditions for the rear brake are severe, and it is difficult to obtain the optimum braking force and optimum braking force curve. Therefore, it becomes necessary for the rear blade brake to continuously and freely adjust the braking force.

Next, the shutter that has completed its travel is charged to a travel ready state, and FIG. 15 shows an overcharged state. In the figure, as described above, the clockwise rotation of the charge lever 15 causes the optically driven lever 9 to
, the rear drive lever 10 is rotated counterclockwise and set to the travel preparation position.

At this time, the front brake lever 16 is pushed by the side surface of its tip 16e by the bottle 9e installed on the lower surface of the light-driven lever 9, and is rotated clockwise around the shaft 8 to be in the set state. At that time, the spring 23 acts to help rotate the front brake lever 16 in the clockwise direction, reducing the load caused by setting the brake at the time of charging.

On the other hand, the rear brake lever 25 is pushed against the side surface of its tip 25d by the pin lOa implanted on the lower surface of the rear drive lever 1°, and is rotated counterclockwise around the shaft 1 to be set. . At that time, the leaf spring 26 acts on the tapered surfaces 25b and 25c of the rear brake lever 25 to help rotate the rear brake lever 25 in the counterclockwise direction, thereby reducing the load caused by setting the brake at the time of charging.

Another way to change the flavor of the braking force is to take advantage of the fact that the rear brake lever is made of synthetic resin.
It is conceivable to arrange the friction surface between the leaf spring of the rear brake lever and the shutter base plate during molding.

For example, in addition to changing the slope of a part of the taper as described above, it is possible to create unevenness or steps on the friction surface as shown in Figures 16 and 17 (part numbers correspond to the previous example). By changing the frictional state of the surface, it is possible to add even more subtle effects to the braking force.

Also, for example, if you make the slope of the taper part of the rear brake lever steeper and increase the displacement range of the presser leaf spring when the rear brake is activated, the leaf spring can be made thinner by stacking several thin leaf springs. The desired pressing force can be obtained without causing the braking force to drop, and the pressing force of the leaf spring itself can cope with changes in the flavor of the braking force.

As explained above, in the embodiment, the brake device for the rear blade, which is delicate and has severe conditions as a brake, is
A brake lever that has an inclined surface and is made of synthetic resin;
It is configured in combination with a leaf spring that applies a pressing force to the inclined surface to generate braking force, and the braking force is continuously changed (gradually increased) according to the amount of actuation of the brake lever. This has the effect of improving the operational durability of the blade.

Furthermore, by forming the brake lever, which was conventionally made of metal, from synthetic resin, it has the effect of alleviating the collision noise between the brake lever and the vane drive lever, which comes into impactful contact with the brake lever.

Furthermore, during charging, the component of the force that the leaf spring applies to the inclined surface of the brake lever acts in the direction of rotating the brake lever to the set state (therefore, it also has the effect of reducing the charging load applied to the brake set. .

Moreover, since it has a simple configuration, the number of parts is small and it does not require a large space, so it is easy to assemble and has great advantages in terms of cost and design freedom.

In addition, the brake device for the rear blade is set so that a wedge is driven in, as shown in Figs. 2, 7, and 10.
The rear brake lever 25 is attached to the fixed part of the plate spring 26 (screw 28
Since the braking force is applied toward the shutter base plate 1 (fixed to the shutter base plate 1 at the Example F), and reliable braking with a short brake stroke can be obtained.

〔Effect of the invention〕

As described above, the present invention was able to provide a suitable shutter braking device by making the braking characteristics of the leading blade brake mechanism and the trailing blade brake mechanism different.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a state in which the shutter is ready for shutter travel according to the embodiment. Figure 2 shows Al-A in Figure 1.
FIG. 3 is a sectional view taken along B1-B1 in FIG. 1. FIG. 4 is a perspective view of C in FIG. 1 of the leading blade brake device. 5 is a plan view showing a state in which the shutter blade in the shutter shown in FIG. 1 approaches the end of travel; FIG. 6 is a plan view showing a state in which the shutter in FIG. 1 is just before the end of the shutter blade travel;
FIG. 7 is a sectional view taken along line A2-A2 in FIG. 6. FIG. 8 is a sectional view taken along line B2-B2 in FIG. 6, and FIG. 9 is a plan view showing a state in which the shutter blade of the shutter shown in FIG. 1 has finished traveling. FIG. 10 is a sectional view taken along line A3-A3 in FIG. 9. FIG. 11 is a sectional view taken along line B3-B3 in FIG. 9. FIG. 12 is a diagram showing the relationship between the brake stroke and braking force of the leading blade brake device. FIG. 13 is a diagram showing the relationship between the brake stroke and braking force of the rear blade brake device. FIG. 14 is a cutaway diagram that makes it easier to see the position of the shutter blade when the shutter blade of FIG. 1 finishes traveling. FIG. 15 is a plan view showing a shutter overcharge state in the shutter of FIG. 1; FIGS. 16 and 17 are sectional views of a rear blade brake device showing other embodiments.

Claims (1)

[Claims] In a shutter brake device that applies braking to the shutter blade almost at the end of its travel, a leading blade brake mechanism with large initial braking is configured for the shutter leading blade, and a leading blade brake mechanism that provides large initial braking is configured for the shutter trailing blade. A shutter braking device characterized by comprising a trailing blade brake mechanism in which initial braking is small and braking force gradually increases.