JPS5932777B2 - Mirror return operation device for single-lens reflex camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mirror return operation device for a single-lens reflex camera, particularly a quick return mirror mechanism.

In a single-lens reflex camera, in addition to a mechanical operating section for photographing operation consisting of a shutter operating mechanism equipped with a quick return mirror mechanism, field light transmitted through a photographing lens is placed in the optical path of the light. In a mechanism configuration that has electrically actuated parts, such as a photometric circuit device that obtains brightness information using a photosensitive element and an electric shutter device that controls shutter speed based on this brightness information, these mechanical actuators are It is well known that a device configuration is required to obtain synchronization or related operation between the camera and the electrical actuator, and the performance of the camera is greatly influenced by the quality of this related operation mechanism.

Therefore, this type of related operating mechanism mainly controls the opening and closing of a switch component that controls an electrically actuating part according to the movement of a mechanically actuating part. The quality of the switch is determined by how the opening/closing operation of the switch component, that is, the response timing and state maintenance are controlled in response to the movement of the actuator.

For example, the power switch of the electrically actuating section is conventionally configured to close in response to the movement of a mechanically actuating member, such as the initial idle rotation range of the shutter lifting lever or the pressing operation range of the shutter release button shaft. It has been done.

According to the former configuration that responds to the shutter lifting lever, the power supply circuit can be closed when necessary by rotating the lever within its play range, regardless of whether the shutter is energized or not. Although this mechanism is convenient for photometry, etc., there is a risk that the power circuit is open during shooting and the electrically actuating part becomes inactive, so this mechanism is not recommended when the electrically actuating part is an electronic shutter mechanism. is not suitable. On the other hand, in the latter case, which closes the power switch in response to the initial press of the shirt release button shaft, the power supply circuit can be reliably closed only when circuit operations such as photometry and release operations are required. While it is effective in terms of related operations and preventing unnecessary consumption of the circuit power supply, it is also effective as a power switch for an electronic shutter mechanism, since at least the shutter close activation special switch must be kept closed. A mechanism is required to hold the taller release button shaft in its depressed release activation position during shutter operation.
Therefore, in order to provide a member to hold the depressed position of the shutter release button shaft and release the mechanism in conjunction with the closing of the shutter, a special operating mechanism must be provided for this purpose. Since the configuration of the operating mechanism is difficult, a relatively simple release means has been adopted in which a shutter charge operation for the next photograph is performed. However, in this case, in order to prevent the power supply battery from being consumed, another switch, which opens when the release operation is completed and closes when the shutter charge operation is performed, must be placed in the circuit in series with the power switch. Moreover, when the release button is held against the release button shaft during a shutter charge operation (operation of the film winding lever), a contact sound is emitted when the shaft returns to the upward position, causing discomfort to the operator or hindering the operation. There was a risk that people might misunderstand that it was terminated. Furthermore, when controlling the electric shutter mechanism under TTL photometry in a single-lens reflex camera, a memory switch for holding photometry information acts on the quick return mirror mechanism as a pre-stage operation for activating the mechanism. It was configured to operate in response to movement of a member in the mechanism.

However, according to this configuration, since the member that controls the memory switch is a pre-operating member of the mirror mechanism (i.e., the shutter activation mechanism), after the switch is activated (memorizes the photometric information), the shutter is actually opened. Since a considerable amount of time passes before the film is exposed, there is a high risk that the brightness of the subject will change between the time of memorization and the time of exposure, which is a practical concern. It was left behind. Furthermore, stability in the operation of the mechanism for measuring the above-mentioned related operations is strongly desired.

In particular, in a mechanism in which the hook member that locks the charge lever of the quick-return mirror mechanism in its stored position is released by the excess movement of the shutter operating mechanism after the release is completed, the stored force activation force is Since the force relationship between the release force of the hook member and the release force of the hook member is delicate, it is necessary to prevent an inconvenient release operation from being performed due to inadvertent external impact or the like. That is, when the stored force energizing spring that drives the shutter is constructed from piano wire, etc. It is already known that the stored power varies considerably depending on the ambient temperature. Also, if a constant elastic spring material is used instead of piano wire, it is possible to obtain a spring member that is not affected by ambient temperature, but there is too much difference in price between these two materials. , the latter has good performance but is expensive, so it lacks practicality. Therefore, when using a spring made of ordinary spring material such as piano wire, it should be designed so that the mirror restoration signal can be generated with a small force, taking into account changes in ambient temperature (especially in low temperature ranges, the stored force deteriorates). There must be. However, if the locking mechanism is constructed so that the locking mechanism can be released by simply applying a small force, there is a risk that the hooking mechanism will become unlatched if some external impact is applied after the mechanism is loaded with energy. .

Therefore, the present invention allows the switch part of the electrically actuating part to face the highly safe mechanically actuating part, so that appropriate continuous operation between these two actuating parts can be measured. The illustrated implementation of the device of the present invention will be described in detail. FIG. 1 is a side view showing the main structure of the side wall of a mirror box of a single-lens reflex camera equipped with the device of the present invention, in which a bell crank lever 1 is connected to the film winding mechanism of the camera and a pin 1a at the bottom. It is rotatably supported.

Reference numeral 2 denotes a mirror flip-up drive lever supported coaxially with the lever 1.

The pin 3a extends from a mirror drive intermediate lever (not shown) disposed on the inner wall of the mirror box through the side wall to the pronged portion 2d of the drive lever 2. The lever 4 is connected to the pin 3
One end has the fitting part with a, the other end faces the action area of the front curtain hook S for starting the shutter, and the synchro contact switch SW3 faces the turning action area of the other end.
Reference numeral 5 denotes a slide plate that is lowered against the energizing force by pressing down the shutter button (not shown).The initial operation of the lowering closes the power switch SW'2, and the final operation closes the mirror mechanism. It is designed to act on the member that controls activation.

First, a spring SPl for accumulating driving force is attached to the above-mentioned component between the bell crank lever 1 and the drive lever 2, and a spring SPl is attached between the lever 1 and the stationary part of the equipment. When the lever 1 rotates back in the counterclockwise direction in the drawing due to the action of the return spring SP2, a part of the side edge of the lever 1 comes into contact with the bent portion 2a of the lever 2, and both levers 1 and 2 are constructed so that they can be rotated back together with each other.

Reference numeral 6 designates a pin for regulating the return rotational position of both the levers 1 and 2. Furthermore, a safety switch SW inserted into the power supply circuit via an insulating pin is connected to the operating portion 1d of the lever 1.
It is designed to act on l. FIG. 2 is a bottom view of the Mirabox according to the first illustrated embodiment, in which a lever 7 whose one end is pressed into contact with an operating pin 1c extending from one end of the bell crank V-1 under the action of a biasing spring SP3 is pivoted. The other end of the lever 7 is suspended by one end of a power storage spring SP4 for driving, which will be described later.

The aperture drive lever 8 and the aperture lever 9 are coaxially supported, and the tip of the bent part 9a of the aperture drive lever 9 faces the edge of one end of the aperture drive lever 8, and there is an angle between the two levers 8 and 9. Under the action of the attached spring SP5, the tip of the bent portion 9a is brought into pressure contact with the side edge, so that normally both levers 8 and 9 rotate integrally. 1
0 has one end brought into contact with the lower end of the slide plate 5 under the action of the spring SP6, and the first
The lever is designed to be able to move up and down in the figure, and a hook pin 10a of a constant height is provided in its intermediate region, and one end 8a of the aperture drive lever 8 is abutted and engaged with the pin 10a.

Reference numeral 11 denotes a mirror flip-up lever, which has a tendency to rotate counterclockwise in the drawing under the application of a spring force, and has a roller 11a at its tip abutting and engaging with the bent portion 2b at one end of the drive lever 2. in a state.

Reference numeral 12 denotes a slide plate hook member, which is configured such that its tip 12a can be engaged with and detached from one side edge of the bell crank lever 1, and a restoring lever having a pin 12b implanted in the lever 12 and a fitting end. The free turning end of No. 13 faces the turning area of the pin P provided at an eccentric position of the shaft gear of the rear curtain shaft.

Further, 14 is a switch base that also serves to regulate the operating range of the aperture drive lever 8, 8b is a protrusion for this regulation, and 8c
is an eccentric pin made of an insulating material and is adapted to act on the memory switch S of the electronic shutter mechanism. In addition, L in the figure is the aperture lever on the lens side. According to the apparatus of the present invention having such a structure, the lower pin 1a of the bell crank lever 1 is pushed by the film winding operation, and the lever 1 is rotated clockwise in FIG. At this time, since the bent portion 2b of the drive lever 2 is locked by the roller 11a of the mirror flip-up lever 11 (state shown in the second figure), the drive lever 2 is held locked at the position shown in the first figure. As a result, the energy storage spring SP1 hooked between the levers 1 and 2 is extended, and the energy storage force necessary for driving the mirror is applied. At the same time, the lever 1
The return spring SP2, which is hooked between the machine and the stationary part of the equipment, is also extended to provide a predetermined stored force. At the end of the rotation of the bell crank lever 11, the tip 12a of the slide hook plate 12, which has a springing tendency to protrude in a direction perpendicular to the moving direction of its lower edge, protrudes from the side edge of the lever 1. engage with this.

This stored force energized state is shown in FIG. At the end of this energy storage operation, one end of the lever 1 closes the safety switch reservoir with its insulated pin. On the other hand, in the bottom mechanism section of the mirror box, the pin 1c of the lever 1 is used to move the accumulating lever 7 for aperture drive against the springing force of the return spring SP3 by the accumulating operation while accumulating the accumulating lever 7. By rotating counterclockwise in the top of FIG. 2, the accumulating spring SP4, which is hooked between the aperture drive lever 8 whose tip 8a is engaged with the lever 10 and the lever 7, is extended. Save energy.

This state is shown in FIG. With the above operation, when the energy storage operation of each operating mechanism is completed and the shutter release button (not shown) is pressed down for photographing, the release slide plate 5 acts in conjunction with this to push down the bent portion 5a. As a result, it is pushed down against the auxiliary spring force.

Then, in the initial operation range of this operation, the power switch 8I is closed, and in the subsequent pressing operation range, if necessary, the check circuit switch is operated to check the photometry state, etc., and then the starting lever 10 is opened at the lower end of the slide plate 5. Pushing one end against the acting force of the energizing spring SP6, the lever 10 is pivoted about the other end, and the tip 8a of the drive lever 8, which had been abuttingly engaged with the locking pin 10a, is moved. Release the lock. Accordingly, the drive lever 8 is rotated counterclockwise in FIG. 2 by the acting force of the energy storage spring SP4, thereby pivoting the narrowing lever 9 that is integrally engaged with the drive lever 8. Then, the lens-side aperture lever L, which had been held at the aperture open control position by the lever 9, moves in response to the lever 9 and begins to narrow down the aperture to a predetermined value. Further, at the beginning of the rotation of the drive lever 8 (when the aperture of the lens is in a substantially open state in terms of light quantity), the memory switch is controlled to be in an open state by the insulating pin 8c.

Then, in the final operating range of the drive lever 8, the tip 8d of the lever 8 acts on the mirror flip-up lever 11 to rotate it clockwise in FIG.
The locking action on the drive lever 2 by a is released.

With this operation, the drive lever 2 is rotated clockwise in FIG. 1 by the stored force of the spring SPl, flips up the mirror (not shown) via the pin 3a, and is linked to this flip-up operation. When the synchro switch & is closed by the lever 4, it simultaneously acts on the front curtain hook S of the shutter to start the shutter opening operation.

On the other hand, the other tip 2c of the lever 2 enters the position where it comes into contact with the overhang piece of the slide plate 5 at the depressed position due to this movement. A state is reached in which the slide plate 5 is prevented from returning upward.

Therefore, even if the release button is released after being operated, the button will return to its original state, but the slide plate 5 will remain in its depressed position, and the power switch will not be activated. l is maintained in a closed state. Then, at the shutter closing operation stage after the predetermined film exposure in the above-mentioned released state, the shutter rear curtain shaft gear rotates, and the pin P implanted at the eccentric position moves clockwise from the second illustrated position. In the final operating range where the shutter rotates approximately half a turn after closing, the pin P contacts the restoring lever 13 and pushes it further, so that the lever 13 is rotated as shown in the figure. Rotate clockwise. As a result, the slide hook plate 12, which is fitted and connected to one end of the lever 13 by the lever 12b, is pulled down against the biasing force. Accordingly, one end 12a of the lever 12 is moved back from the abutting side edge of the bell crank lever 1, and the locking and holding action on the lever 1 is released. Thereupon, the lever 1 is rotated counterclockwise in FIG. 1 by the accumulated force of the return spring SP2 together with the drive lever 2, which is integrated with the side edge of the bent portion 2a. As a result of this operation, the slide plate 5, which was held at the active end 2e of the drive lever 2, is also released from its lock and returned to its upward position due to the energizing force, returning to the initial state when the power switch was released. All will return. As described above, according to the device of the present invention, in the mechanism in which the member for locking the charge lever of the quick return mirror mechanism receives a signal from the surplus movement after the exposure of the shutter is completed, the release operation is performed. The member (in the illustrated embodiment, the slide plate 12) is prevented from being released directly or via an intermediate member (the lever 13) at the charge state position of the member (the pin P) that is moved by the shutter charge operation. By allowing the release operation of the hook member when the member returns to its movement after the film exposure is completed, it is possible to reliably prevent the hook member from becoming unhooked due to an unexpected sudden action.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of a mirror box side placement mechanism equipped with the device of the present invention, and FIG. 2 is a bottom view showing an embodiment of the box bottom placement mechanism. 1...Bell crank lever, 2...Drive lever 3...Pin, 4...1...Lever,
5...Slide plate, 6...Pin, 7.
...- Lever, 8 ... Aperture drive lever, 9.
-・・・Aperture lever, 10...Lever 1
1...-Mirror flip-up 7 lever 12...
...-Slide plate hook member 613...Lever, power switch, 8...Memory switch.

Claims (1)

[Claims] 1. A return member that returns the mirror to the focusing position, a hook member that locks this member, and moves in synchronization with shutter closing to release the lock of the hook member and return the mirror, and 1. A mirror return operation device for a single-lens reflex camera, comprising a moving member that moves in synchronization with the accumulation of a return force of a return member and, after accumulation of force, assumes a position that prevents release of the hook member.