JPS6291925A - Film transportation mode switching device - Google Patents

Abstract

PURPOSE:To reduce the number of parts and the man-hour for assembling by operating a mode switch with the inclination of a revolving shaft of an epicyclic gear which is caused when rotation of a driving shaft of a motor is stopped by tension of a film. CONSTITUTION:A film 13 is tensed between a spool 1 and a cartridge shaft 16a when auxiliary winding will be completed; and when a motor 3 is driven continuously in the forward direction, the first gear 7 and the second gear 8 joined with the first gear 7 are moved epicylically, and the first gear 7 is pushed to the front by the motor gear 3 while keeping the engaging part between the second gear 8 and a spool interlocking gear 10, ad the first and second gears 7 and 8 are moved forward while inclining a revolving shaft 6. Then, the lower end of the revolving shaft 6 rides on an edge 23a of a holding lever 23. The inclination of the revolving shaft 6 is held when the tooth edge of the first gear 7 slips off that of the motor gear 3, and a mode switch 32 provided in the moving route of the revolving shaft 6 is turned on.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a film transport mode switching device for a camera that drives a motor to wind up the film.

[Conventional technology]

In a camera that transports film by driving a motor, it is necessary to switch the film transport mode by detecting the winding end of the film, that is, when the film is fully pulled out from the cartridge. For example, with a pre-winding camera that winds all the film in the cartridge onto a spool and then winds the film back into the cartridge one frame at a time for every - number of shots,
In the winding mode, the film is transferred from the cartridge side to the spool side, and after the film winding end is detected, the preliminary winding mode is switched to the photographing mode, and the film is transferred from the spool side to the cartridge side. In addition, even in a normal camera that winds the film stored in the cartridge onto the spool one frame at a time after each shooting, the end of the film is detected when the film is wound up after the last frame has been taken, and I am trying to switch from shadow mode to rewind mode.

Incidentally, the film transport mode switching signal is obtained by, for example, monitoring the drive current of the motor. That is, when the motor is further driven after winding of the film by the spool is completed, the film becomes tense and the spool load increases. Along with this, the current of the motor driving the spool increases rapidly, and if this is detected electrically, a mode switching signal can be obtained. If the direction of rotation of the motor is changed when this mode switching signal is obtained, the film transport mode can be automatically switched.

In addition, a planetary gear is provided in the gear train leading from the motor to the spool, and when the motor is driven, the rotation of the spool is not prevented due to the tension of the film, and the planetary gear makes planetary movement. Some devices are designed to automatically switch the film transport mode. In this case, the planetary gear displaced by the planetary motion is meshed with another transmission drive system, thereby mechanically switching the film transport mode.

[Problem that the invention seeks to solve]

However, a method in which the mode switching signal is electrically detected from the drive current of the motor has the disadvantage that the circuit tends to be complicated and malfunctions are likely to occur due to fluctuations in the power supply voltage. In addition, in a device that mechanically switches the film transport mode by displacement of a planetary gear, after the planetary gear is displaced between each mode position, in order to securely hold it there, the planetary gear must be displaced with high torque. However, there are disadvantages in that the motor becomes larger and the structure becomes more complex.

The present invention was made in view of the drawbacks of the conventional technology, and is not affected by fluctuations in power supply voltage, etc.
Moreover, it is an object of the present invention to provide a film transport mode switching device that does not complicate the drive transmission mechanism from the motor to the spool.

[Means for solving problems]

To achieve the above object, the present invention includes a gear train for transmitting driving force from a motor to a spool, when the motor is driven in the normal rotation direction with the spool being prevented from rotating. A planetary gear that is displaced is provided, and when the planetary gear is displaced, a rotation axis of the planetary gear is tilted. The rotating shaft is held in an inclined position by a holding lever, and when the rotating shaft is in the inclined position, a mode switch is activated and a mode switching signal is output. When the mode switching signal is obtained in this way, the motor that was being driven in the forward direction is now driven in the reverse direction, and the film that was being wound onto the spool is now rewound onto the cartridge shaft. .

An embodiment of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 1 showing an example of the use of the present invention in a pre-winding type camera, a spool 1 formed in a cylindrical shape is rotatable with respect to the camera body. A motor 2 is provided inside the spool 1, and the motor 2 has a screw hole 2a.
It is fixed to the camera body via. A drive shaft 2b of a motor 2 projects through the lower open end of the spool 1, and a motor gear 3 is fixed to the tip thereof. A rotating shaft 6 is implanted in the support arm 5 that is formed integrally with the camera body 4, and a first gear 7 that meshes with the motor gear 3 and a first gear 7 that is integrated with the first gear 7 are attached to the rotating shaft 6. A second gear which rotates as follows is rotatably attached. Note that the support arm 5 is formed in a part of the camera body 4 made by plastic molding, for example, so as to protrude in an elongated manner, and has elasticity at least in the torsional direction.

The second gear 8 meshes with a spool interlocking gear 10, and the gear 11 integrated with the spool interlocking gear IO meshes with a spool gear 12 fixed to the lower end of the spool 1. Therefore, when the motor 2 rotates normally and the motor gear 3 rotates in the direction of the arrow in the figure, the spool 1 rotates counterclockwise, that is, in the direction in which the film 13 is wound up.

Further, the rotation of the motor gear 3 is controlled by a well-known one-way clutch 1.
4 to the cartridge gear 15. However, when the motor gear 3 rotates in the direction of the arrow, that is, in the direction in which the spool 1 winds up the film 13, the one-way clutch 14 does not transmit the driving force to the cartridge gear 15. Patrone gear 1
5 includes a fork 1 that engages with the cartridge shaft 1.6a.
7 are integrated. Therefore, when the spool l rotates in the direction to wind up the film 13, the cartridge gear 15 is
is rotated as the film 13 is transported.

A control lever 21 is rotatably attached to the camera body via a shaft 20. The control lever 21 has a flexible elastic lever 22, a holding lever 23, and a release lever 24. The tip of the elastic lever 22 is in contact with a stopper 25. A holding edge 23a having a curved peripheral edge is formed at the tip of the holding lever 23, and in the illustrated state, the edge 23a is located slightly away from the free end of the rotating shaft 6. ing.

The release lever 24 is in contact with one end of an opening/closing lever 28 that rotates in conjunction with opening and closing of the back M21 of the camera. The opening/closing lever 28 is rotatable about a shaft 29 and biased counterclockwise by a spring 30. Therefore, when the 'AM 27 is opened, the opening/closing lever 28 is rotated counterclockwise and the release lever 24 is thereby pressed. It will be rotated to a position that balances the force.

A pair of contact pieces 32a facing the tip of the rotating shaft 6,
A moat switch 32 including 32b is provided. When the pair of contact pieces 32a and 32b are not in contact as shown in the figure, a preliminary winding mode signal is output from the mode switch 32 to the motor drive circuit 33. When the pre-winding mode signal is supplied to the motor drive circuit 33, the motor drive circuit 33 rotates the motor 2 in the normal direction, that is, the film 1 is placed on the spool 1.
3 in the winding direction. On the other hand, when the rotating shaft 6 is tilted and the contact pieces 32a and 32b come into contact as described later, the mode switch 32 outputs a photographing mode signal, and in this case, the motor 2 is driven in the reverse direction. It has become.

FIG. 1 shows a state in which the cartridge 16 is loaded into the camera, the back cover 27 is closed, and preliminary winding is in progress. In the preliminary winding mode, mode switch 3
2, a preliminary winding mode signal is input to the motor drive circuit 33, and the motor gear 5 rotates in the direction of the arrow. The film 13 stored in the cartridge 16 is then wound onto the spool 1. At this time, the cartridge gear 15 is not driven by the action of the one-way clutch I40.

The end portion of the film 13 is fixed to the cartridge shaft 16a. Therefore, when the preliminary winding is completed, the film 13 is strongly tensioned between the spool 1 and the cartridge shaft 16a, and rotation of the spool 1 is prevented by the film 13 being tensioned. When the motor 3 continues to be driven in the forward rotation direction, the first gear 7 and the second gear 8 integral therewith perform planetary motion and are displaced from the illustrated position. That is, the first gear 7 is pushed toward the front in the figure by the motor gear 3 while the meshing portion between the second gear 8 and the spool interlocking gear 10 is in opposition, and the first gear 7 and the second gear 8 are It moves forward by tilting the rotating shaft 6. At this time, since the support arm 5 has an elongated shape, it is twisted by its own elasticity, but the upper end of the rotating shaft 6 does not move, so as a result, the lower end of the rotating shaft 6 moves forward. It will be moved and tilted.

The lower end of the rotation shaft 6, which has thus moved forward, rides on the edge 23a of the holding lever 23.

Then, the inclination of the rotating shaft 6 is maintained at the position where the first gear is disengaged from the motor gear 3, that is, at the position where the tooth tips of the first gear 7 are disengaged from the tooth tips of the motor gear 3, as shown in FIG. be done. By holding the rotation shaft 6 in this inclined position, the mode switch 32 provided within the movement path of the rotation shaft 6 is turned on. In this way, the mode switch 32 is turned on.
The signal is sent to the motor drive circuit 33 as a photographing mode signal.
, the direction of rotation of the motor 2, which had been driven in the normal rotation direction, is switched and is now driven in the reverse rotation direction.

When the motor 2 reverses, the cartridge gear 15 is driven in the direction of the arrow via the motor gear 3 and the one-way clutch 14 that acts in the direction of transmitting the driving force, and the fork 17 is driven in the direction of the arrow.
This causes the cartridge shaft 16a to rotate. The film 13 is then rewound onto the cartridge shaft 16a.

During this time, the tip of the rotating shaft 6 remains held at the position where it rides on the edge 23a, so the meshing between the first gear 7 and the motor gear 3 is released, and the spool 1 is not driven by the motor 2. It is rotated as the film 13 is transported.

As the motor 2 reverses and the film 13 is transferred, the driven sprocket 35 engaged with the perforations 13a of the film 13 rotates. A conductive wire 36 is fixed to the driven sprocket 35,
When the driven sprocket 35 has made just one rotation, a one-component switch 38 made up of a pair of contact pieces is brought into conduction by the wire 36. The driven sprocket 35 has eight engaging teeth and rotates once when the film 13 is transferred one frame, so the one frame switch 38
3 is transferred by one frame, a conduction signal is output.

The conduction signal obtained from the one-frame switch 38 is supplied to the motor drive circuit 33, and this signal is used as a drive stop signal for the motor 2. When the motor 2 stops driving in this way, the camera enters a photography standby state. Thereafter, the motor 2 is driven every time the shutter is operated, and this drive is stopped by a conductive signal from the single-frame switch 38, and the film 13 is
is rewound frame by frame into Patrone 16. After the final frame has been photographed, the entire film 13 is wound into the cartridge 16 and the motor 2 is stopped to complete the photographing.

When the back cover 27 is opened to take out the cartridge 16 from the camera, as shown in FIG.
7a retreats from one end of the opening/closing lever 28. Then, the opening/closing lever 28 is rotated counterclockwise by the bias of the spring 30. As a result, the other end of the opening/closing lever 28 pushes the release lever 24, so the control lever 21 rotates clockwise while bending the elastic lever 22. When the control lever 21 rotates in this manner, the holding lever 23 also rotates clockwise in unison, so that the holding edge 23a is retracted from the back side of the rotating shaft 6. As a result, the rotating shaft 6 is returned to its initial position before being tilted by the restoring force of the twisted support arm 5. In addition, Edge 2
Since the outer circumference of 3a is curved, the holding lever 23
When rotating clockwise, the rotation is not obstructed by the rotation shaft 6, and the rotation shaft 6 is also smoothly moved to the position shown in FIG. 3.

By thus returning the rotation shaft 6 to its initial position,
The first gear 7 is meshed with the motor gear 3, and
The mode switch 32 is reset to the OFF state, ie, the preliminary winding mode.

However, when the back cover 27 is open, the power switch (not shown) is in the OFF state, so the motor 2 will not be driven in the reverse direction.

When a new film cartridge is loaded again and the back cover 27 is closed, the opening/closing lever 28 is rotated clockwise by the pressure of the protrusion 27a of the back cover 27. Then, the control lever 21
is rotated following the opening/closing lever 28 by the bias of the elastic lever 22, and the release lever 24 is returned to the position where it abuts the end of the opening/closing lever 28. As a result, the holding lever 23 also returns to the initial position shown in FIG. At this time,
Since the mode switch 32 has been reset to a state in which it outputs a preliminary winding mode signal, the above-described sequence is automatically repeated when the power switch is turned on by closing the back cover 27.

In this way, if it is detected through the mode switch 32 that is switched by the inclination of the rotating shaft 6 itself that the planetary gear consisting of the first gear and the second gear is displaced by the planetary motion, the tlFA gear can be displaced. This eliminates the need for a swinging lever to support the structure, making it possible to avoid complicating the structure. It should be noted that such a film transport mode switching mechanism can equally be applied to an ordinary camera that winds the film onto a spool one frame at a time for each photographing period. In this case, when the final frame has been photographed and the film has been wound onto the spool, the film is continuously rewound into the cartridge.

In addition, in order to support the rotating shaft 6 in a tiltable manner, instead of using the elastic support arm 5 as described above, a bendable joint is provided on a part of the rotating shaft 6, and this is attached to the camera body. It may be attached.

〔Effect of the invention〕

As explained above, with the film transport mode switching device of the present invention, when the rotation of the drive shaft of the motor is blocked due to film tension, the rotation axis of the planet gear itself can be tilted. This is used to activate the mode switch. Therefore, an electrical film transport mode switching signal can be obtained without being affected by the power supply voltage for driving the motor. Further, since the mechanical structure is not complicated while utilizing the displacement of the 'tri gear, it is possible to reduce the number of parts and the number of assembly steps.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a film feeding mechanism of a camera using the present invention. FIG. 2 is a plan view of main parts showing a state in which the film transport mode has been switched. FIG. 3 is a plan view of main parts showing a state in which the back cover is opened. 1... Spool 2... Motor 3... Motor gear 5... Support arm 6... Rotating shaft 7
...First gear 8...Second gear 10...Spool interlocking gear 12...Spool gear 13...Film 1
6...Patrone shaft 16a...Patrone shaft 23...
Holding lever 27...Back cover 28...Opening/closing lever 32...Mode switch.

Claims (4)

[Claims] (1) From the first film transport mode in which the motor is rotated forward to wind the film onto the spool, when it is detected that the film has been wound onto the spool to the end, the motor is reversed and the film is wound onto the spool. In a camera that automatically switches to the second film transport mode, which rewinds the film that is currently being loaded onto the cartridge shaft, the gear train is installed in the gear train to transmit the driving force of the motor to the spool, and prevents the spool from rotating. a planetary gear that is displaced when the motor is rotated in the forward direction in a state where the motor is rotated in the normal direction; a rotating shaft that rotatably supports the planetary gear and is tilted by the displacement of the planetary gear; and a rotating shaft that is tilted by the displacement of the planetary gear; a mode switch that is activated to output a switching signal; and a holding lever that holds the rotating shaft in the tilted position when the rotating shaft is tilted, and when a switching signal is obtained from the mode switch. A film transport mode switching device characterized in that the first film transport mode is switched to the second film transport mode by reversing the motor. (2) The film transport mode switching device according to claim 1, wherein the planetary gear is displaced so that the driving force of the motor is not transmitted to the spool. (3) Film transfer mode switching according to claim 2, wherein the holding lever releases the holding of the rotating shaft in conjunction with opening of the back cover of the camera. Device. (4) The rotating shaft has one end planted in a supporting member having elasticity in the torsional direction and the other end being a free end, and when the rotating shaft is tilted while the supporting member is twisted. 4. A film transport mode switching device according to claim 3, wherein a mode switch is operated through said free end.