JPS6255645B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film holding mechanism for a camera.

Generally, the film is pressed down from the top and bottom edges by a pressure plate and guide rails to keep the film screen flat, but when the cartridge and film screen are placed close together, as in a small camera, Despite the above-mentioned fixation, the film is not fixed sufficiently, resulting in curling and blurring of the corners of the film screen, and the film screen is scratched when the film is wound.

It is an object of the present invention to provide a film holding mechanism which can reliably hold a film screen flat during photographing and can be separated from the film after photographing without damaging the film screen.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, the camera is a single-lens reflex camera in which the film 1 is wound up and unwinded by driving a spool 2 or a cartridge 3, respectively, by motors. A lifting amount regulating mechanism 4 is provided to interlock with the shutter release. This regulation mechanism 4
The sprocket 8 includes a plurality of protrusions 6 that bite into the perforation 5 of the film 1 and a notch 7 formed in a part, and a sprocket 8 whose one rotation corresponds to one winding amount. An arm 11 is provided with a claw portion 9 at its tip that engages with the portion 7 and is rotatable around a pin 10 at the rear, and a shutter.
It is provided with a lever 12 that locks with the arm 11 at the time of release and is rotatable counterclockwise around a pin 10. The arm 11 is also provided with a spring 13 that biases the film backward, a spring 14 that biases the film toward the winding side, and a pin 10 that is movable in the direction of the arrow by the force of the spring 13. long hole 15
and a contact pin 16, and a switch 17 is provided which comes into contact with the contact pin 16 and turns on a drive motor (described later) when the arm 11 moves in the direction of the arrow by the spring 13. This switch 17
may be replaced with a simple signal, for example, the second
Conductor 18 on sprocket 8 as shown
The conductor 18 may be wound up one time by the section 19, and this signal may be sent to the LSI to operate the motor. Reference numeral 20 is a presser lever that presses the outside of the film screen in order to flatten the film screen. Thus, when the cutout 7 of the sprocket 8 and the claw 9 of the arm 11 are engaged, the spring 22 causes the presser lever 20 to press the emulsion side of the film screen with the presser 21. , and the pressure plate 23 on the back side presses the film, keeping the film screen flat (third
figure). Further, an elastic member 24 such as rubber may be attached to this holding portion 21 (FIG. 2).

On the other hand, when the switch 17 is turned on, the drive motor 26 for winding up the film and winding up the film is stored in its motor compartment as shown in detail in FIGS. 1 and 5. The frame is divided into two parts along a plane parallel to the rotation axis of the motor. That is, one side is the cover 27 and the other side is the board 2.
8 and the cover 27 is screwed onto the substrate 28. A rotary body 32 consisting of a core portion 30 and a coil portion 31 provided on the rotating shaft 29 is disposed within the motor storage frame between the cover 27 and the board 28. Board 2
A plurality of magnets 33 are attached to 8. Further, a commutator 34 and worm gears 35 and 36 are attached to both ends of the rotating shaft 29, and both ends are fixed to the cover 27 via bearings 37. Thus, when current is applied to brush 38, motor 26 rotates.

On the back side of this board 28, there is a motor 2.
A film winding gear group 40, a film rewinding gear group 65, and a shutter and release gear group 50 are provided, which rotate the film winding and unwinding shaft in conjunction with the film winding gear 65. The film winding gear group 40 has a gear 41 that meshes with a worm gear 35 attached to one side of the rotating shaft 29 of the motor, and a support shaft 43 having a sun gear 42 at its lower end and supported by the cover 27 at its upper end. The sun gear 42 is provided with planetary gears 45 which are connected to each other by a connecting rod 44 and mesh with each other, and when the planetary gears 45 rotate counterclockwise, the planetary gears 45 mesh with each other and the film is A gear 46 for rotating the winding shaft 2 is provided. When the connecting rod 44 rotates and the planetary gear 45 and the gear 46 mesh with each other, a stopper pin 47 that the connecting rod 44 comes into contact with and a stopper pin 47 that prevents the connecting rod 44 from rotating in order to maintain an appropriate meshing interval are provided. A pin 48 is provided. On the other hand, the shutter release gear group 50 includes a worm gear 3 provided on the other end side of the rotating shaft 29 of the motor.
6, and a support shaft 53 having a sun gear 52 at its lower end is supported by the cover 27 at its upper end. A planetary gear 55 is provided which meshes, and a gear 56 which meshes when the planetary gear 55 rotates counterclockwise is provided. Further, a release plate 57 is provided which comes into contact with the connecting rod 54 when the connecting rod 54 rotates in the direction.
A release spring 58 is provided which urges against the rotation in this direction. A cam 59 is coaxially attached to this gear 56, and the lever 60 engages with this cam 59 to obtain a charged state of the shutter. A spring 61 is attached to the gear 56 for correcting the amount of film winding. In addition, a stopper pin 62 and a rotation prevention pin 63 are provided on which the connecting rod 54 comes into contact in order to maintain an appropriate meshing interval when the planetary gear 55 rotates and meshes with the gear 56. On the other hand, the film rewinding gear group 65 includes a sun gear 66 that meshes with a gear 52 provided coaxially with the gear 51 that engages with the worm gear 36, and is connected to the sun gear 66 by a connecting rod 67. and a planetary gear 68 which is in mesh with each other, and when the planetary gear 68 rotates counterclockwise, the unwinding shaft 3
A gear 69 is provided which meshes to rotate the .

Thus, when the shutter is released, the lever 12 rotates counterclockwise about the pin 10, and the arm 11 also rotates counterclockwise against the force of the spring 14. Therefore, the claw portion 9 at the tip of the arm 11 is disengaged from the notch portion 7 of the sprocket 8, and at the same time, the arm 11 is pulled by the force of the spring 13 and moves in the direction of the arrow, and is also pulled by the spring 14. Because of this, the arm rotates clockwise again, and the claw portion 9 comes into contact with the lower part of the circumferential side of the sprocket 5.

On the other hand, the contact pin 16 on the arm 11 turns on the switch 17 and rotates the motor 26. Furthermore, as the arm moves in the direction of the arrow, the film screen presser lever 20 rotates counterclockwise against the force of the spring 22, so that the film screen is separated from the presser lever 20. And motor 26
When turned on, the rotating shaft 29 of the motor clockwise rotates the gear 41 meshing with the worm gear 35 at one end. As the gear 41 rotates in this direction, the sun gear 42 also rotates in the same direction, and the planetary gear 45 meshing with the gear 42 rotates counterclockwise while being rotated clockwise by the connecting rod 44. The clockwise rotation is transmitted to the gear 46 as it rotates and meshes with the gear 46 . Therefore, the winding shaft 2 provided on the gear 45 rotates and moves the film in the winding direction as shown in FIG. 5A. Due to this movement of the film, the protrusion 6 of the sprocket 8 engages with the perforation 5 of the film, and when the sprocket 8 rotates once and returns to its original position, the tip of the arm 11 touches the claw part 9. As it re-engages with the notch in the sprocket 8, the inertia of its rotation causes the arm 11 to move slightly upward against the force of the spring 13, turning off the switch 17 of the motor 26.
On the other hand, due to the rotation of the rotating shaft 29 of the motor 26, the gear 51 meshes with the worm gear 36 at the other end.
The sun gear 52 at the lower end rotates counterclockwise, and the planetary gear 55 meshed with this gear 52 rotates clockwise and connects the connecting rod 54.
rotates counterclockwise to mesh with the gear 56, the connecting rod 54 compresses the spring 58 of the release plate 57, and the cam 59 and lever 60 engage,
The shutter is thus charged (Fig. 5A). Then, the arm 11 and the sprocket 8
switch 17 for motor 26 by engagement with
turns OFF and motor 26 stops, gear 5
1 and 52 stop rotating, the counterclockwise rotation of the connecting rod 54 releases the spring 58 of the release plate 57.
The force compressing the is released, the connecting rod 54 is rotated clockwise by the biasing force of the spring 58, the gears 55 and 56 are separated, and the lever 60 is moved in the direction of the arrow, so that the shutter is moved again. The camera enters the released state (Fig. 5B). Also, the switch 17 is OFF.
However, a reverse current may be applied to the motor before the motor is de-energized. Then, by reversing the motor, the gear 46 of the hoisting shaft and the planetary gear 45 meshed with this gear 46 move away from each other in the opposite direction to the gear group, and the shutter gear is turned on the other side. gear 56 and this gear 56
The planetary gear 55 which is in mesh with the planetary gear 55 is separated by an operation opposite to the above-mentioned operation. Thus, the shutter release state is again obtained in the same manner (FIG. 5B).

Also, by engaging the claw portion 9 of the arm and the notch portion 7 of the sprocket 8, the presser lever 20
The force of the spring 22 is released and rotates clockwise, so that the holding portion 21 presses the outside of the film screen, and the film screen becomes flat.

As the film is wound up in this manner, when the time required to wind the film becomes longer than a predetermined time, the motor begins to rotate in reverse.
This rotation causes gears 45 and 46 on the winding side and gears 55 and 56 on the shutter release side to separate from each other. On the other hand, due to this rotation, the gear 52
Since it rotates clockwise, the sun gear 66 that meshes with this gear 52 rotates counterclockwise, and the planetary gear 68 that meshes with this gear 66 rotates clockwise and connects the connecting rod 67. Therefore, it rotates counterclockwise and meshes with the gear 69 of the winding shaft. Since this gear 69 rotates counterclockwise, the film is wound onto the winding shaft 3 (fifth
Figure c).

FIGS. 6 and 7 are a motor drive circuit and time chart using the above mechanism, and are designated by the symbol S ₂
is a switch that turns on when the switch is released, rotates the motor, and turns off when the differential is completed, while _S3 is a power switch. The symbol M is a motor.

Initially, when the film is loaded, switch S ₂ is on, so if you turn on the power switch S ₃ after loading the film, Q ₇ , Q ₈ , Q ₉ will pass through R ₁₁ .
A current flows through the motor M in the direction of arrow a, causing the motor to rotate in the forward direction and start winding. Then, after winding has been completed for a certain length, the switch _S2 is turned off and the motor M is stopped. This state is shown by a line passing through the dotted line in the time chart of FIG.

On the other hand, when the winding is completed and the time required for winding exceeds a predetermined time, _the motor _M is reversely rotated to perform _the winding operation. Decided on long t ₂ , R ₅ ~ C ₂
The time constant is set to be slightly longer than the normal rewinding time. Thus, if the switch _S2 is ON for longer than the time _t1 ' (determined by _R3 to _C1 ) set to be longer than the normal winding time, it is clear from the time chart that it is initially OFF. Since Q ₂ turns on, the current flowing through R ₁₁ flows through D ₂ , and Q ₇ ,
Q ₈ and Q ₉ turn OFF and Q ₃ turns OFF at the same time.
Q ₄ , Q ₅ , and Q ₆ turn ON, and current flows through the motor in the direction of arrow b, causing it to rotate in reverse. On the other hand, Q ₂ turns ON and after a certain period of time (slightly longer than the normal unwinding time t ₂ determined by R ₅ and C ₂ ), Q ₃ turns ON again.
Q ₄ , Q ₅ , and Q ₆ are all turned OFF and the motor stops.

According to the film holding mechanism according to the present invention, since the holding part that presses down the film screen from the light-receiving side of the film during photographing is provided in contact with the outside of the film screen, the film screen can be reliably kept flat. , because it does not cause curling, the positive parts of the film screen will not be blurred, and
Since the presser member separates from the film after photographing is completed, the film screen is not scratched during the film winding operation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts of a motor-driven camera according to the present invention, FIG. 2 is a perspective view showing a modification of the winding amount regulating mechanism and film holding member of the camera shown in FIG. 1, and FIG. 1 is a side view showing the film holding state of the film holding member shown in FIG. 1, FIG. 4 is a side view showing another embodiment of the holding mechanism of the film holding member, and FIG. 5A, B, and C are a sectional view, and FIG. 5 is a plan view for explaining the operation of a gear that performs film winding and unwinding operations in a camera according to the present invention. FIG. 6 is a motor drive circuit diagram, and FIG. FIG. 7 is a time chart of motor drive in FIG. 6. 1... Film, 20... Presser lever, 21...
...presser section, 22... spring, 23... pressure plate, 24...
...Elastic member.

Claims (1)

[Claims] 1 by engaging with the perforation of the film.
A sprocket that rotates once per frame, a notch provided on a part of the outer periphery of this sprocket, and a first sprocket that presses the film from the light receiving side against a pressure plate outside the film screen to hold the film screen flat. The presser member, which is biased in the presser direction by the elastic member, has a claw portion at the tip and can swing between an engaged position and a non-engaged position with the notch, and the claw portion is an arm movable to swing along the outer periphery of the sprocket; an engaging portion provided on the arm that engages with the presser member; and an arm that slides and urges the arm in a direction opposite to the winding direction of the sprocket. and a third elastic member that biases the claw portion of the arm in the direction of the engagement position. By forcibly swinging to the non-engaging position, the arm is moved by the second elastic member, and this movement causes the engaging portion of the arm to separate the presser member from the film against the biasing force of the first elastic member. A film holding mechanism for a camera, characterized in that the arm is returned to its original position by engagement between a notch and a pawl after one revolution of the sprocket.