JPS6127728B2 - - Google Patents

Description

Detailed Description of the Invention This invention relates to the rotation of a holding shaft such as a front shaft or a rear shaft that winds and holds a shutter membrane or a shutter string and is rotated at the time of shutter release to enable the movement of these membranes or strings. This invention relates to a brake mechanism for a focal plane shutter that stops the shutter.

Conventionally, as this type of brake mechanism, one is known in which a gear that rotates coaxially with a holding shaft is provided and used in combination with another gear mechanism. but,
Such a brake mechanism not only has a complicated structure, but also requires a considerable amount of space below the holding shaft, which has been an obstacle to miniaturizing the camera.

Therefore, the purpose of this invention is to simplify the construction and
Another object of the present invention is to provide a brake mechanism for a focal plane shutter that does not require space below a holding shaft.

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 (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. As shown in detail in FIGS. 3 and 4, rotating shaft holes 1f and 1g are formed in the lower end surface of this protrusion and the upper end surface of the string winding portion 1b, respectively. Soshi〓〓〓〓
The tip shaft 1 having such a structure as a lever is formed by integral molding of synthetic resin. Near the tip 1 above,
A rear shaft (holding shaft) 2 is provided parallel to this as shown in FIG. At the lower part of the main body 2a of the rear shaft 2, there is an engagement notch 2 on the side surface, similar to the front shaft 1.
The protrusion with d carved therein and the eccentric engagement pin 2e
is formed by integral molding of synthetic resin. And the rotation shaft holes 2f and 2g are provided on the lower end surface and the upper end surface.
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 support plates 3 of the camera body.
Upper metal pins 4, 4 are protruded and fixed to the lower end surfaces, and similar lower metal pins 5, 5 are inserted into the rotating shaft holes 1f, 2f provided on the lower end surface. Axis 2 is relative to the camera body.
It is rotatably supported around its axis. A front pinion 6 and a rear pinion 7 are attached to the lower metal pins 5, 5, respectively.
coaxially arranged so as to be slidable along the 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 rotatable so that one end 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 front engagement lever and the rear engagement lever provided in the figure are shown respectively. These engaging levers 10 and 11 are provided with electromagnets 12 and 13 that attract the other ends of these levers to perform the engaging operation, and tension springs 14 and 15 that make these engaging operations more reliable. ing. Reference numeral 16 in FIG. 1 indicates a mirror drive gear which is rotated in accordance with the shutter release operation, and an eccentric cam 17 is coaxially attached to the inner surface of this gear, and a mirror drive pin 18 is provided protrudingly. has been done. This drive pin 18
The mirror 1 is provided on the camera body so as to be rotatable between a lower position and an upper position around the upper end.
It is inserted into a cam groove 21 of a cam plate 20 attached to the side surface of the cam plate 9. Thus, the mirror 19 is rotated between the above two positions by the rotation of the drive gear 16. Further, the free end of the clutch spring 8 is moved in accordance with the rotation of the mirror 19.
The movable pin 22 has its upper end in contact with the cam surface of the eccentric cam 17, and its lower end in contact with 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,
As the mirror 19 is rotated to its upper position, it is pushed down and brought to the lowest position just before the upper position, so that the pinions 6 and 7 are engaged with the shafts 1 and 2 by their respective engagement pins. Pinion 6,
7 is lowered via clutch spring 8. 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 in order to restrict 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. The outer peripheral side of the main body 1a of the tip shaft 1 is curved along the outer peripheral side, and the upper and lower ends are provided with string winding parts 1b, 1c.
A brake piece 23 extending up to 23 is pinned at one end thereof. The upper end 23a and lower end 23b of this brake piece 23 are connected to the string winding part 1.
As shown in FIG. 5, it can be inserted into slots formed on the outer periphery of the parts b and 1c. 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 23 is press-fitted into the
is rotated inwardly using the one side end as a fulcrum, and is substantially abutted against the outer circumferential 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 becomes the tip shaft body.
It is separated from the outer circumferential side of 1a. In this embodiment, 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 has leg portions 25b and 25c formed by bending the upper and lower ends of the main body 25a. These legs 25b, 25c are pivotally supported by the camera body, and thus the braking member 25 is rotatable about this pivot point.
Further, a tension spring 26 is attached to the lower leg portion 25c.
As a result, the braking member 25 is always urged to rotate in a direction opposite to the direction of rotation of the front shaft 1 when the shutter is operated. Rotation in this direction and rotation in the opposite direction are performed by the stop pin 2.
7 and 28 are regulated within a predetermined range by coming into contact with the legs. The main body 2 of this braking member 25
5a has a frictional engagement surface 25d slightly inclined with respect to the outer circumferential surface of the tip shaft body 1a, and an abutting engagement portion 25e located at the 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 membrane 29 and the rear membrane 30 of the focal plane shutter shown in FIG. A tube 32 is provided. A tip membrane 29 can be wound around the tip tube 31, and a string (shutter string) 33 of the tip membrane 29 can be wound around the string winding portions 1b, 1c of the tip barrel 1. On the other hand, a string (shutter string) 34 of a rear membrane 30 can be wound around the rear cylinder 31, and this rear membrane 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 membrane 32 is 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 engagement levers are engaged by the tension springs 14 and 15. It is held by engagement with 10 and 11. 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 excited and the engagement lever 10,
11, and the mirror drive gear 16 is rotated clockwise. As a result, the mirror 19 is rotated to the upper position via the pin 18 and the cam plate 21, 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 lowest position just before the mirror 19 is at the highest position.
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 barrel 31 is greater than the engagement force of the engagement lever 10 due only to the tension spring 14, so the front barrel 31 causes the front barrel 1 to move over the front membrane 29 and its String 33
is rotated clockwise through the so-called leading membrane 29.
starts running. Similarly, the other electromagnet 1
3 is also deenergized, the rear membrane 30 also starts running, and a shutter operation is performed. When the front shaft 1 and the rear shaft 2 rotate a predetermined amount (two revolutions), the brake mechanism is activated to stop these shafts 1 and 2, and the mirror 1
9 as well as the clutch spring are returned to their original positions 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.
When the brake piece 23 is wound around the string winding portion 1b, the free end of the upper end portion 23a of the brake piece 23 is press-fitted into the slit of the winding portion 1b by the string 33.
Even if the front shaft 1 continues to rotate, no braking force is applied. Then, just before the end of the shutter operation, when the wound string 33 no longer touches 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 3 is the frictional engagement surface 25 of the braking member 25
d, and finally 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 acts, that is, exerts a buffering effect. It is becoming more and more common to have one.

In the device of the above embodiment, the holding shafts (front shaft and rear shaft) can be rotated by inserting fixing pins from above and below into the rotation shaft holes drilled in the upper and lower end surfaces respectively. It was installed, but the 9th
As shown in the figure, 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, the brake mechanism according to the present invention is provided on a holding shaft such as a front shaft or a rear shaft, and is pressed against the holding shaft by the shutter membrane or the winding of the shutter string, and during rotation of the holding shaft, the a brake piece having an engaging part that protrudes from the holding shaft when the pressure is released; and a brake piece that is provided near the holding shaft and engages with the engaging part of the brake piece that projects from the holding shaft to hold the holding shaft. The structure is simple because it includes a braking member that stops the rotation of the shaft. Furthermore, there is no need to provide the brake mechanism at the bottom of the holding shaft, and the peripheral area of the holding shaft, which was considered a waste of space, can be used, allowing the camera to be made more compact.

Further, as in the embodiment, if the braking member is supported by an elastic member such as a coil spring, a buffering effect can be provided, so that no unreasonable force is applied to the brake mechanism and the holding shaft.

In the above embodiment, a rotatable spring plate with one end supported by the holding shaft was used as the brake piece, but a pin-shaped brake provided so as to be able to protrude into a hole or groove drilled in the holding shaft may also be used. It may be one piece, and these brake pieces do not necessarily need to be supported by the holding shaft as long as they do not separate from the holding shaft.

[Brief explanation of the drawing]

1 to 8 relate to a shutter mechanism of a camera equipped with a brake 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 a perspective view during shutter release operation. FIG. 3 is a sectional view showing the clutch mechanism during clutch operation, FIG. 4 is a sectional view showing the clutch mechanism in a released state, 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. DESCRIPTION OF SYMBOLS 1... Front shaft (holding shaft), 1b, 1c... String winding part, 1d... Engagement notch, 2... Rear shaft (holding shaft), 19... Mirror, 23... Brake piece, 2
4... Coil spring, 25... Braking member, 26...
Tension spring, 29... Front membrane, 30... Back membrane, 33
... String of anterior membrane, 34... String of posterior membrane. 〓〓〓〓

Claims (1)

[Scope of Claims] 1. It is provided on a rotatable holding shaft so as to wind and hold a shutter membrane or shutter string, and is pressed against this by the winding of the shutter membrane or shutter string, and the winding is held during rotation of the holding shaft. a brake piece having an engaging part that protrudes from the holding shaft when the pressure is released; and a brake piece that is provided near the holding shaft and engages with the engaging part of the brake piece that projects from the holding shaft. A brake mechanism for a focal plane shutter, comprising a braking member for stopping rotation of a holding shaft. 2. The brake mechanism for a focal plane shutter according to claim 1, wherein the brake piece is located between the upper and lower ends of a shutter membrane or a shutter string. 3. A brake mechanism for a focal plane shutter according to claim 1 or 2, wherein the braking member is elastically mounted so as to have a buffering effect. 4. The brake mechanism for a focal plane shutter according to claim 1, 2 or 3, wherein the brake piece is biased in the protruding direction by a spring provided on the holding shaft.