JPS6150295B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention involves the rotation of a holding shaft in which the front shaft is the rear shaft, which winds and holds the shutter curtain or shutter string, and is rotated at the time of shutter release to enable the movement of these membranes or strings. This article relates to a focal plane shutter clutch mechanism that achieves the following functions.

Conventionally, this type of clutch mechanism has consisted of a pinion coaxially fixed to a holding shaft and a gear partially provided with a notch so that it can selectively mesh with the pinion. Are known.
However, with such a conventional clutch mechanism, the positional relationship between the starting pinion and the gear must be accurate, making assembly work difficult.

Therefore, an object of the present invention is to provide a clutch mechanism for a focal plane shutter that does not require a very high degree of precision and is easy to assemble.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A holding shaft for a focal plane shutter according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

Reference numeral 1 in FIG. 1 indicates a tip shaft (holding shaft) that is rotatable around a vertical axis, and this is a small-diameter main body 1a.
and a large diameter string winding section 1 formed at both ends of this.
b, 1c. Furthermore, a protrusion having an engagement notch 1d formed on the side surface is provided on the lower end face of the lower string winding part 1c, and an engagement pin 1e is protruded from the lower end of the protrusion at an eccentric position. ing. Rotating shaft holes 1f and 1g are formed in the lower end surface of this main part and the upper end surface of the string winding part 1b, respectively, as shown in detail in FIGS. 3 and 4.
The tip shaft 1 having such a structure is formed of an integral type of synthetic resin. A rear shaft (holding shaft) 2 is provided near and parallel to the front shaft 1, as shown in FIG. The main body 2a of this rear shaft 2
At the lower part of the shaft 1, a protrusion having an engaging notch 2d carved on the side surface and an eccentric engaging pin 2e are integrally molded from synthetic resin. And the rotary shaft hole 2 is provided on the lower end surface and the upper end surface.
f and 2g are bored as shown in FIG. The rotation shaft holes 1g and 2g provided on the upper end surfaces of the front shaft 1 and the rear shaft 2 are provided with upper metal pins 4 and 4 which are protruded and fixed to the support plate 3 of the camera body.
However, the rotation shaft holes 1f and 2f provided on the lower end surface
Similar lower metal pins 5, 5 are inserted into the camera body, and the front shaft 1 and rear shaft 2 are rotatably supported relative to the camera body about their axes. A front pinion 6 and a rear pinion 7 are coaxially provided on both of the lower metal pins 5, 5 so as to be slidable along the pinions 5, 5, respectively. These pinions 6, 7 are engaged with the engagement pins 1e, 2e of the front shaft 1 and rear shaft 2, respectively, at these upwardly moved positions, and rotate the pinions 6, 7 together with these shafts 1, 2. an engagement pin 6a for
7a is provided eccentrically and protrudes upward. These pinions 6, 7 are located on the free end of a common clutch spring 8 in the form of a leaf spring, one end of which is fixed to the camera body, and are normally held in the upward movement position.
When the free end is pressed down by a pin, which will be described later, it is brought to a downward movement position and the engagement between the engagement pins is released. Further, a common gear 9 is meshed with these pinions 6, 7, which is rotated in conjunction with the film winding operation, and rotates these pinions 6, 7 by a predetermined amount, usually two rotations. The thickness and vertical position of this common gear 9 are taken into consideration so that the pinions 6 and 7 are always in mesh with each other regardless of their moving positions. Reference numerals 10 and 11 in FIG. 1 are rotatably provided so that one end thereof engages with notches 1d and 2d formed in the front shaft 1 and rear shaft 2 to prevent rotation of these shafts 1 and 2. The first engagement lever and the engagement lever are shown respectively. These engaging levers 10, 11 are provided with electromagnets 12, 13 that attract the other ends of these levers to accomplish the engaging operation, and tension springs 14, 1 for making these engaging operations more reliable.
5 are provided respectively. Reference numeral 16 in FIG. 1 indicates a mirror drive gear that rotates in accordance with the shutter release operation, and an eccentric cam 17 is provided on the inner surface of the gear.
are coaxially attached, and a mirror drive pin 18 is provided protrudingly. This drive pin 18 is inserted into a cam groove 21 of a cam plate 20 attached to the side surface of a mirror 19 that is rotatably provided in the camera body between a lower position and an upper position around the upper end. There is. Thus, the mirror 19 is rotated between the above two positions by the rotation of the drive gear 16. Further, in order to move the free end of the clutch spring 8 according to the rotation of the mirror 19, the movable pin 22 has its upper end abutted against the cam surface of the eccentric cam 17, and its lower end is brought into contact with the cam surface of the clutch spring 8. It is provided in contact with the free end of. This movable pin 22
follows the rotation of the eccentric cam 17, and the mirror 1
As the pinion 9 is rotated to the upper position, it is pushed down, and just before the upper position, it is brought to the lowest position and the pinions 6 and 7 are engaged with the shafts 1 and 2 by their respective engagement pins. The pinions 6 and 7 are lowered via the clutch spring 8 so as to release the clutch. In this way, the clutch mechanisms for the front axle 1 and the rear axle 2 are constructed. Further, the front axle 1 and the rear axle 2 are each provided with a brake mechanism for regulating their rotation to a predetermined amount. Since the principle of these brake mechanisms is the same for both the brake mechanism provided on the front axle 1 and the one provided on the rear axle, the one provided on the front axle will be described below. On the outer peripheral side of the main body 1a of the tip shaft 1,
It curves along this, and the upper and lower ends are the string winding part 1b,
A brake piece 23 extending up to 1c is pinned at one end thereof. The upper end 23a and lower end 23b of this brake piece 23 are inserted into fifth slots formed on the outer circumferential sides of the string winding parts 1b and 1c.
It can be inserted as shown in the figure. The brake piece 23 is made of an elastic metal plate, so that when the shutter string is wound around the string winding portions 1b and 1c, the upper end portion 23a and the lower end portion 23b are held in the slot by this string. This brake piece 2 is press-fitted into the
3 is rotated inward about the one side end as a fulcrum, and is substantially brought into contact with the outer peripheral side of the tip shaft main body 1a. and,
When the winding of the shutter string around the string winding portions 1b and 1c is released, the brake piece 23 is rotated outward by its own elastic force, and its free end is separated from the outer peripheral side of the tip shaft body 1a. In this implementation, in order to ensure the outward rotation of the brake piece 23, as shown in FIGS. 6 to 8,
A coil spring 24 is inserted into the slot of the string winding portions 1b, 1c for urging the free end of the brake piece 23 to rotate outward. On the other hand, a braking member 25 is disposed near the front shaft 1 in a corresponding manner. This braking member 25
As shown in FIG. 5, the main body 25a extends vertically along the tip shaft main body 1a, and legs 25b and 25c are formed by bending the upper and lower ends of the main body 25a. . These legs 25b, 25c are pivotally supported on the camera body, and thus the braking member 25
can rotate around this pivot point. Further, a tension spring 26 is connected to the lower leg portion 25c, and as a result, this braking member 2
5 is always urged to rotate in a direction opposite to the direction of rotation of the front shaft 1 when the shutter is operated. The rotation in this direction and the rotation in the opposite direction are restricted within a predetermined range by the stop pins 27 and 28 coming into contact with the legs. The main body 25a of this braking member 25 has a frictional engagement surface 25d slightly inclined with respect to the outer circumferential surface of the front shaft main body 1a, and an abutting engagement portion 25e located at the terminal end of this engagement surface. .
The brake mechanism of the rear axle 2 is constructed almost the same as that of the front axle 1, except that the free end of the brake piece itself can be inserted into a long groove formed in the main body 2a.

The front curtain 29 and rear membrane 30 of the focal plane shutter shown in FIG. It is equipped with 32. A front curtain 29 can be wound around this front cylinder 31, and a string of this front curtain 29 (shutter string)
33 can be wound around the string winding portions 1b and 1c of the front shaft 1. On the other hand, a string (shutter string) 34 of a rear curtain 30 can be wound around the rear cylinder 31, and this rear curtain 30 can be wound around the main body 2a of the rear shaft 2.

The operation of the shutter mechanism configured as described above will be explained below.

First, by performing a winding operation using a film winding lever (not shown), the common gear 9 is rotated in the direction of the arrow in FIG.
The string 33 of the leading curtain and the trailing curtain 32 are respectively wound up.
In this state, the electromagnets 12 and 13 are deenergized, but the front shaft 1 and the rear shaft 2 are engaged with the pinions 6 and 7 that mesh with the common gear 9, respectively, and the tension spring 1
It is held by engagement with the engagement levers 10 and 11 by the engagement levers 4 and 15. Of course, the mirror 19 is in the lower position. Incidentally, FIG. 1 shows the state at this time. Next, when the release button is pressed to start the photographing operation, the electromagnets 12 and 13 are activated by the engaging levers 10 and 11.
At the same time, the mirror drive gear 16 is rotated clockwise. As a result, mirror 19 is connected to pin 1.
8 and the cam plate 21 to the upper position, resulting in the state shown in FIG. Further, the movable pin 22 is pushed down by the rotation of the mirror drive gear 16 via the eccentric cam 17, and the clutch spring 8 is rotated to the lowermost position just before the uppermost position of the mirror 19. Therefore, the pinions 6 and 7 attached to the clutch spring 8 are also moved downward, and the engagement pins 6a and 7a of these pinions 6 and 7 and the engagement pins 1e and 1e of the front shaft 1 and the rear shaft 2 are moved downward. The engagement with 2e is released. Next, when one of the electromagnets 12 is deenergized, the charging force of the front tube 31 is greater than the engagement force of the engagement lever 10 due to only the tension spring 14, so the front tube 31
1, the front shaft 1 is rotated clockwise via the front curtain 29 and its string 33, and the so-called running of the front curtain 29 is started. Similarly, the other electromagnet 13
is also deenergized, the trailing curtain 30 also starts running, and a shutter operation is performed. Then, when the front axle 1 and the rear axle 2 rotate a predetermined amount (two rotations), the brake mechanism is activated to stop these axes 1 and 2, and the mirror 19
The clutch spring is also returned to its original position as shown in FIG. The operation of the brake mechanism of the front shaft 1 at this time is as shown in FIGS. 6 to 8. That is,
As shown in FIG. 6, when the string 33 of the front curtain is wound around the string winding part 1b of the front axle 1, the free end of the upper end 23a of the brake piece 23 is connected to the slit of the winding part 1b by the string 33. It is press-fitted inside, and even if the front shaft 1 continues to rotate, no braking force will be applied. Then, just before the end of the shutter operation, when the wound string 33 no longer hits the free end of the brake piece 23 as shown in FIG. It extends from the slot and protrudes from the outer circumferential side of the tip shaft 1. And as shown in Figure 7,
When this protruding free end reaches the braking member 25, it is braked by this member 25 and its rotation is stopped. The braking force at this time is first
The protruding free end of the friction engagement surface 25d of the braking member 25
, and finally abuts on the abutting engagement portion, and during these braking operations, the braking member 25 is rotated against the tension spring 26, so that the braking member 25 gradually works, that is, has a buffering effect. It's getting old.

In the device of the above embodiment, the holding shafts (tip and rear shafts) are rotatably installed by inserting fixing pins from above and below into rotating shaft holes drilled in their upper and lower end surfaces, respectively. However, as shown in FIG. 9, a rotating shaft hole 1g penetrating from the upper end surface to the lower end surface of the holding shaft 1 may be formed, and one fixing pin 5 may be inserted through this hole. .

As explained above, in the clutch mechanism according to the present invention, unlike the front and rear shafts, the pinion is not fixed to the holding shaft, and the pinion is detached from the holding shaft when the mirror rises. There is no increase in inertia due to the pinion when rotating. Moreover, according to the present invention, the clutch mechanism is configured to engage and disengage the pinion gear in the axial direction of the holding shaft in conjunction with the mirror drive member that drives the mirror, so the accuracy during assembly is not affected much. It requires no attention and is easy to manufacture.

Incidentally, in the above embodiment, it may be operatively connected to, for example, a release button. Also, 2 for the front axle and the rear axle.
Although the two pinions are simultaneously moved by one clutch spring to engage and disengage, they may be operated independently, or the other may be operated by a separate clutch mechanism.

[Brief explanation of the drawing]

1 to 8 relate to a shutter mechanism of a camera equipped with a clutch mechanism according to an embodiment of the present invention, in which FIG. 1 is an overall perspective view before shutter release, and FIG. 2 is during shutter release operation. FIG. 3 is a cross-sectional view showing the clutch mechanism during clutch operation, FIG. 4 is a cross-sectional view showing the clutch mechanism when the clutch is released, FIG. 5 is a perspective view showing the brake mechanism, and FIG. 8 to 8 are sectional views showing the brake mechanism in different states for explaining the brake operation, and FIG. 9 is a sectional view showing a modified example of the holding shaft. 1... Tip shaft (holding shaft), 1e... Engagement pin, 2
... Rear shaft (holding shaft), 2e ... Engagement pin, 6 ...
Front pinion, 7... Rear pinion, 6a... Engagement pin, 7a... Engagement pin, 8... Clutch spring, 9
...Common gear, 16...Mirror drive gear, 17...
...Eccentric cam, 19...Mirror, 22...Movable pin, 29...Front curtain, 30...Rear curtain.

Claims (1)

[Claims] 1. A rotatable holding shaft for winding and holding the shutter curtain or shutter string, a pinion gear that engages with the holding shaft in opposition to the holding shaft in the axial direction and rotates the holding shaft to perform winding, and an axis of the holding shaft. a support member for the pinion gear that is movable in the direction and engages and disengages the pinion gear from the holding shaft; and a support member for the pinion gear that operates in response to a release operation to raise the mirror and move the support member to move the pinion gear from the holding shaft. What is claimed is: 1. A clutch mechanism for a focal plane shutter, comprising: a mirror drive member for detaching the mirror;