JPH0233134B2 - JIDOMAKIMODOSHIKAMERA - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic rewind camera that rewinds the photographic film by reversing the motor when the photographic film stops running. The present invention relates to a device for resetting a timer circuit for determining the running condition of photographic film.

Conventional automatic rewind cameras are equipped with a capacitor that is periodically discharged by the film travel signal, and the capacitor is continuously charged when it is no longer possible to pull out the photographic film from the cartridge. . This capacitor charging voltage and a reference voltage obtained by dividing the power supply voltage are input to a comparator, and when the capacitor charging voltage becomes larger than the reference voltage, the comparator is inverted. When this comparator is reversed, the forward rotation circuit is turned off and the reverse rotation circuit is turned on instead, causing the motor to reverse rotation and begin rewinding the photographic film.

For example, a 3V power supply is used as the power supply,
The camera mechanism operates normally until the voltage drops to about 1V. However, if the voltage of the power supply decreases due to wear and tear from use, and if the load on the motor increases due to shutter setting during winding, the voltage applied to the motor will drop to nearly 1V, causing the motor to stop rotating. When this motor stops rotating, a reversal circuit is formed as described above. Rewinding photographic film requires a smaller load than winding because there is no shutter set, so the voltage applied to the motor can be restored to 1V or higher. As a result, the motor rotates in reverse and rewinds the photographic film even during the middle of photography.

SUMMARY OF THE INVENTION In view of the above background, an object of the present invention is to provide an automatic rewinding camera that does not cause photographic film to be rewound even if the power supply is consumed and the voltage drops. be.

The present invention prevents the formation of a motor reversal circuit by forming a discharge path for the capacitor when the voltage drops to such a level that the motor stops midway through winding due to the load on the camera mechanism. At the same time, a lamp that was flashing while the film was running is turned on to notify the user that the power is low.

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

In FIG. 1, a motor 1 for driving a camera mechanism has a special structure in which it is also used as a take-up spool 2 for the purpose of making the camera smaller. That is, the stator is used as the take-up spool 2,
A rotor is housed within this take-up spool 2. A plurality of claws 3 are formed on the lower outer periphery of the take-up spool 2, and a photographic film 4 is attached to the claws 3.
perforation 4a is engaged.

A shaft 5 is provided parallel to the take-up spool 2, and guide roller support arms 6 and 7 are rotatably supported on the upper and lower parts of the shaft 5, respectively. The upper guide roller support arm 6 is biased counterclockwise by a spring 8, and by pressing the guide roller 9 supported at its tip against the outer circumferential surface of the take-up spool 2, the outer circumference of the take-up spool 2 is To prevent loosening of photographic film 4 wound up. Similarly, the lower guide roller support arm 7 is also urged counterclockwise by a spring 10. The guide roller 11 supported by the guide roller support arm 7 has a diameter reduced at the portion facing the claw 3, and presses the photographic film 4 at the upper and lower positions of the claw 3. Therefore, this guide roller 11 is
Perflation 4a of photographic film 4 is nail 3
It acts to engage.

A spool shaft 13 is fixed to the upper part of the take-up spool 2, and a hole 13a of this spool shaft 13
The rotating shaft 14 of the motor 1 protrudes upwardly through the shaft. Two E-rings 15 and 16 are fixed to the rotating shaft 14 at appropriate intervals. A drive gear 17 is loosely fitted to the rotating shaft 14 between these E-rings 15 and 16.
It is pressed against the upper E-ring 16 by a spring 18. Since the drive gear 17 and the rotation shaft 14 are frictionally connected by the spring 18, when a load of a certain value or more is applied to the drive gear 17, the rotation of the rotation shaft 14 is not transmitted to the drive gear 17.

A cylindrical leaf spring 19 is fitted around the outer periphery of the spool shaft 13. Projecting piece 19 of this cylindrical leaf spring 19
a fits into the notch 20a of the spool drive gear 20. Since the spool drive gear 20 and the take-up spool 2 are frictionally connected by the cylindrical leaf spring 19, when a load of more than a certain value is applied to the take-up spool 2, the spool drive gear 2
0 rotation is not transmitted to the take-up spool 2. Note that this spool drive gear 20 and the take-up spool 2
The frictional coupling between the rotary shaft 14 and the drive gear 17 is weaker than the frictional coupling between the rotating shaft 14 and the drive gear 17.

The rotation of the drive gear 17 is controlled by gears 22, 23, 24, 25, 26, which constitute a reduction gear train.
The signal is transmitted to gear 28 via 27. This gear 2
8 is fixed to the sprocket shaft 29, so
When the motor 1 rotates, the sprocket shaft 29 rotates. A driving sprocket 30 is fixed to the sprocket shaft 29, and its pawl 30a engages with a perforation 4a of the photographic film 4 to transport the photographic film 4. During winding, this drive sprocket 30 rotates 480 degrees in the direction of the solid line to transport the photographic film 4 by one frame.

A gear 32 is fixed to the upper part of the sprocket shaft 29, and this gear 32 drives a gear 34 via a gear 33. These gears 33, 34
is provided on the counter return lever 35. The gear 34 is provided with an intermittent feed shaft 36 having a V-shaped notch, which meshes with a ratchet wheel 37 to rotate the ratchet wheel 37 by one pitch with one rotation of the intermittent feed shaft 36. When the ratchet wheel 37 rotates by one pitch against the restoring spring 38, a counter disc 39 fixed to the ratchet wheel 37 also rotates, and the number of film frames that have been photographed is displayed based on the value that matches the index 40. do.

A back cover detection section 35a is provided on the counter return lever 35, and when the back cover (not shown) of the camera is closed, a spring 4 is attached to the back cover detection section 35a.
1 acts in the direction of the arrow, the counter return lever 35 rotates counterclockwise, causing the intermittent feed shaft 36 to mesh with the ratchet wheel 37. Conversely, when the back cover is opened, the counter return lever 35 rotates clockwise and the intermittent feed shaft 36 and ratchet wheel 37 are disengaged. In this case, the ratchet wheel 37 and the counter disc 39
is returned to the starting piece "S" by the restoring spring 38.

The counter disk 39 is provided with a protrusion 39a that indicates the idle feed section, and this protrusion 39
The pin 42 is pushed by a. This pin 42 is installed in an idle feed detection lever 43, and by rotating it clockwise against a spring 44, a pin 45 turns on the idle feed switch S1.

The gear 28 meshes with a gear 46, which also meshes with the spool drive gear 20. Here, when winding the photographic film 4 for one frame, the gear 28 rotates 480 degrees, and the gear 46 rotates 360 degrees.
Rotate degrees. A control cam 47 for controlling frame feeding and a shutter setting cam 48 for setting the shutter are provided coaxially with this gear 46.

A feed claw 50 is provided on the lower surface of the gear 28, and engages with the ratchet wheel 51 only during rewinding to rotate it in the direction shown by the dotted line. A gear 52 is fixed to the lower surface of the ratchet wheel 51. This rotation of gear 52 is transmitted to gear 55 via gears 53 and 54. An E-ring 57 is attached to the upper part of a rotating shaft 56 on which a gear 55 is fixed, and holds the gear 58 so that it does not slip out. These gears 5
A spring 59 is disposed between gears 55 and 58, and this spring 59 causes gears 55 and 58 to
are frictionally coupled, and when a load of a certain value or more is applied to the gear 58, the rotational force of the gear 55 is not transmitted to the gear 58. Further, a gear 60 meshes with the gear 58, and a rewinding pawl 61 is provided coaxially with the gear 60. This rewinding claw 61
is coupled to a spool housed within a cartridge (not shown).

In order to detect the running condition of the photographic film 4,
A driven sprocket 62 is provided which engages the perforation 4a. Note that a roller or the like may be used in place of the driven sprocket 62 and rotated by the photographic film 4. This driven sprocket 62 is provided with a plurality of pins 63, for example six pins, and when the sprocket 62 rotates, the movable contact piece pushed by the pin 63 comes into contact with the fixed contact piece, and the film travel detection switch S2 is activated.
Turn on to generate a film running signal.

In FIG. 2, a control lever 65 for controlling frame feeding is supported by a shaft 66, and when the photographic film 4 is transferred by one frame, a protrusion 65a provided on a part of the lever 65a is moved by a spring 67. It falls into the notch 47a of the control cam 47 under the tensile force of , and at the same time, the frame advance switch S3 for stopping the rotation of the motor 1 is switched from contact a to contact b. In addition, contact b turns off the forward rotation circuit of motor 1.
Therefore, the state in which it is in contact with contact b is said to be OFF, and the state in which it is in contact with contact a is said to be ON.

The shutter cam 48 has a leaf shape, and a pin 69 of a shutter set lever 68 comes into contact with the outer periphery of the shutter cam 48. The shutter set lever 68 pivots counterclockwise until the shutter set cam 48 rotates 180 degrees, and the shutter set lever 68 pivots clockwise while the shutter set cam 48 rotates 180 degrees to 360 degrees. Therefore, every time the shutter set cam 48 rotates once, the shutter set lever 68 reciprocates once.

When the shutter set lever 68 pivots counterclockwise, its free end pushes the bent portion 70a of the shutter drive lever 70 and moves it to the right. This shutter drive lever 70 sets the shutter (not shown) when moving to the right.
Then, the shutter is opened when returning to the left due to the accumulated force of the spring 81. Further, when the shutter drive lever 70 moves to the right, its vertical portion 70b pushes the bent portion 71a of the interlocking lever 71 to move it to the right. A spring 6 is provided between the interlocking lever 71 and the control lever 65.
7 is hung, and a spring 74 is also hung between it and the locking lever 73. Therefore, when the interlocking lever 71 moves to the right, the locking lever 73 pivots counterclockwise, and at the same time, the spring 67 is loaded.

The release lever 75 has a horizontal groove 76a and a vertical groove 7.
6b is formed, and the free end of the locking lever 73 is inserted into this groove. When the shutter is set, the locking lever 73 is inserted into the vertical groove 76b, and if the release lever 75 is pushed down against the spring 77 in this state, the pin 78 of the release lever 75 will push the shutter lever 79 and pin 80 is released, the shutter drive lever 70 is moved to the left by the spring 81. When the release lever 75 rises, the locking lever 73 enters the horizontal groove 76a, so the interlocking lever 71 is released and returns to the left end while pushing the locking lever 73 by the stored force of the spring 72. When the interlocking lever 71 returns, the vertical portion 71b pushes the free end of the control lever 65 and rotates it clockwise, causing the protrusion 6
5a from the notch of the control cam 47. Note that when the interlocking lever 71 returns, the springs 67 and 74 are not loaded with energy.

FIG. 3 shows the motor control circuit. When the relay switch S4 for forward rotation is connected to contact a and the relay switch S5 for reverse rotation is connected to contact b, the power supply 85 and motor 1 are connected in series, and the motor 1 rotates in the normal direction to transfer the photographic film 4. is wound onto the take-up spool 2. Conversely, when the forward rotation relay switch S4 is connected to contact b and the reverse rotation relay switch S5 is connected to contact a, the motor 1 rotates in the reverse direction and rewinds the photographic film 4.

A CR time setting circuit consisting of a resistor 86 and a capacitor 87 is connected between the connection point P and the frame advance switch S3. This resistor 86 and capacitor 87
The + side input terminal of the comparator 88 is connected to the connection point A with. This comparator 88 -
The side input terminal is connected to a connection point B between resistors 89 and 90. These elements constitute a timer circuit that measures a time t that is shorter than the time T required to wind up one frame of photographic film 4 and is sufficient to determine the film running state (see Fig. 5). reference). That is, when the capacitor 87 is continuously charged, when a time t shorter than the time T has elapsed, the voltage at the connection point A rises to the voltage at the connection point B, and the output terminal of the comparator 88 is set to "L". to "H". A forward rotation relay coil (hereinafter simply referred to as a forward rotation relay) 91 is connected to the output terminal of this comparator 88, and when the output terminal of the comparator 88 is "L", electricity is applied, and the forward rotation relay switch S4 is connected to a contact point. b
Switch from to contact a. and comparator 8
8 is reversed, the forward rotation relay switch S
4 is connected to contact b.

The frame advance switch S3 is used for the photographic film 4.
When one frame is wound up, it connects to contact b and
The output terminal of the comparator 88 becomes "H" and the forward rotation relay 91 is turned off. Further, a resistor 92 forming a discharge path of the capacitor 87 is connected to the contact b. A jump feed switch S1 is connected in parallel with this frame feed switch S3, and is turned ON during the winding of the jump feed frame following the start frame, and turned OFF during the winding of the first frame.
Therefore, the jump feed switch S1 energizes the forward rotation relay 91 to continue rotating the motor 1 even if the frame feed switch S3 is turned off within the jump feed section.

A transistor 93 is connected in parallel with the capacitor 87.
is connected, and is turned ON by a pulse signal from a differentiating circuit 94 such as a one-shot multivibrator, thereby discharging the capacitor 87. As a result, while the photographic film 4 is running, the forward rotation timer circuit is reset at regular intervals. As shown in FIG. 7, the differentiation circuit 94 is activated at the falling edge of the film running signal generated by the film running detection switch S2, and outputs a pulse signal. Since the differential circuit 94 is provided, even if the driven sprocket 62 stops rotating with the film detection switch S2 turned on, the forward rotation timer circuit will not be held in the reset state. The pulse signal may be output at the rising edge of the film running signal, or a plurality of pulse signals may be output in response to one film running signal.
Since a lamp 95 is connected to the output terminal of the differential circuit 94, the running state of the photographic film 4 is displayed by blinking the lamp 95. The forward rotation timer circuit has a delay time shorter than one frame, and is reset in synchronization with the rotation of the driven sprocket 62. As a result, even if the perforation 4a is torn by the drive sprocket 30 when the photographic film 4 cannot be pulled out from the cartridge, the forward rotation timer circuit is activated before the frame advance switch S3 is turned OFF. This allows rewinding without continuing frame forwarding. If this perforation 4a is not to be broken, the film running signal can be obtained in synchronization with the rotation of the drive sprocket 30, or the delay time of the forward rotation timer circuit can be made longer than one frame. good.

A capacitor 96 and a resistor 97 are connected in series between the connection point Q and the frame advance switch S3. The connection point between the capacitor 96 and the resistor 97 is connected to the + side input terminal of the comparator 98, and the connection point between the resistors 99 and 100 is connected to the - side input terminal. This timer circuit is activated when the frame advance switch S3 is connected to the contact 3a at the start of frame advance, and the time for the output terminal of the comparator 98 to invert from "H" to "L" is set to the forward rotation relay switch S4. This delay is sufficient for switching from contact b to contact a. In this case, when the forward rotation relay switch S4 is connected to contact a, the timer circuit becomes inactive, so the output terminal of the comparator 98 remains at "H". It also operates when forward relay switch S4 leaves contact a and switches to contact b to rewind photographic film 4, thereby delaying comparator 98. After this delay, the output terminal of the comparator 98 is set to "L" to energize the reversing relay coil (hereinafter simply referred to as reversing relay) 101 and switching the reversing relay switch S5 to contact a. Further, this comparator 98 is also used to cut off the reverse rotation relay 101 and stop the motor 1 during reverse rotation when the frame advance switch S3 is turned off after rewinding is completed.

A resistor 10 is connected between the anode of the power source 85 and the connection point P.
2, a series circuit of capacitor 103, and resistor 104
and 105 series circuits are connected to each other. The connection point C between the resistor 102 and the capacitor 103 is connected to the + side input terminal of the comparator 106, and the connection point D between the low resistors 104 and 105 is connected to the - side input terminal. This reversal timer circuit is activated when the reversing relay switch S5 is connected to contact a to form a reversing circuit for the motor 1, and the capacitor 103 is continuously charged and the voltage at point C changes to the voltage at point D. The output terminal of the comparator 106 is set to "L" only during the time the voltage rises to the voltage. Note that this time is desirably set to be relatively long in order to completely wrap the leading edge of the photographic film 4 into the cartridge. A transistor 107 is connected in parallel with the capacitor 103, and is turned on by a pulse signal from a differentiating circuit 94.

The comparators 98 and 106 are open collectors, and when either one is "L", the reversing relay 101 is energized. The comparator 98 is used to regulate the start and end of energization of the reversing relay 101.
6 acts in the meantime and is used to reverse the motor 1 and rewind the photographic film 4 into the cartridge. When the power supply voltage decreases, the rotation of the motor 1 stops due to the load on the camera mechanism during winding.
At this time, a somewhat smaller current flows through the capacitor 87 than in the normal state, so when a time slightly longer than the delay time t has passed, the comparator 88 is reversed from "L" to "H" and a reverse circuit for the motor 1 is formed. be done.

To prevent this, a voltage detection circuit 108 is provided, and when the voltage of the power supply 85 drops to a predetermined value, the transistor 109 is turned on. When this transistor 109 turns on, the lamp 95 lights up, and when the motor 1 rotates in the forward direction, the transistor 93 turns on, and when the motor 1 rotates in the reverse direction, the transistor 10 turns on.
7 turns on.

As shown in FIG. 4, the voltage detection circuit 108 is composed of resistors 110 and 111 that divide the power supply voltage, a transistor 112, and a resistor 113 connected to the collector of this transistor. Then, the transistor 112
is turned off, so the transistor 109 is turned on.

The rewinding switch S6 is used when rewinding the photographic film from the middle, and when the rewinding switch S6 is turned on, the reversing relay 101 is energized. After that, comparator 9
Since the reversing relay 101 is turned on by 8 and 106, reversing continues even if the rewinding switch S6 is released.

Next, the operation of the present invention having the above configuration will be explained with reference to FIGS. 5 and 6.

After engaging the rewind claw 61 with the spool of the cartridge, the leading end of the photographic film 4 is pulled out and the perforation 4a is moved to the drive sprocket 30.
and the pawl of the driven sprocket 62. When the back cover is closed, the back cover detection part 35a is pushed in the direction of the arrow, so the counter return lever 35 pivots counterclockwise to engage the intermittent feed shaft 36 with the ratchet wheel 37.

At the start of winding, the shutter drive lever 70 has moved to the right due to the previous rewinding and is now locked with the shutter lever 79. At this time, the free end of the locking lever 73 has entered into the vertical groove 76b.

Therefore, when the release lever 75 is pressed down first, the shutter lever 79 is pivoted clockwise by the pin 78, and the pin 8 of the shutter drive lever 70 is rotated clockwise by the pin 78.
Release 0. As a result, the shutter drive lever 70 moves to the left, and the shutter is opened and closed during this movement. When you release your finger from the release lever 75,
Since this moves upward, the free end of the locking lever 73 enters the horizontal groove 76a. This locking lever 73 releases the locking of the interlocking lever 71 biased by the spring 72, and is pushed by the locking lever 71 to pivot clockwise. When the interlocking lever 71 moves to the left, the control lever 65 connected by the spring 67 is simultaneously rotated clockwise to extract the protrusion 65a from the notch 47a of the control cam 47. When the control lever 65 is rotated clockwise, the frame feed switch S3 is switched from contact b to contact a and is turned on.

When the frame advance switch S3 is turned on, the output terminal of the comparator 88 becomes "L", so that the forward rotation relay 91 is energized and the forward rotation relay switch S4 is switched from contact b to contact a. On the other hand, since the reversing relay 101 is cut off, the reversing relay switch S5 is connected to contact b. When the motor 1 starts normal rotation, the rotation of the motor 1 is transmitted to the drive gear 17 that is frictionally coupled to the rotating shaft 14 . This rotation of drive gear 17 is transmitted to gear 28 via a reduction gear train, causing sprocket shaft 29 to rotate by 490 degrees. As a result, the drive sprocket 30 rotates in the direction of the solid line and moves the photographic film 4 to the left.

On the other hand, the rotation of the sprocket shaft 29 is controlled by the gear 46.
is transmitted to the spool drive gear 20 via. The rotation of this spool drive gear 20 is caused by the rotation of the cylindrical leaf spring 1.
Spool shaft 1 frictionally connected by 9
3, and the spool shaft 13 rotates together with the take-up spool 2 fixed to its lower end. This spool shaft 13 is considerably slowed down compared to the rotating shaft 14 of the motor 1, and since the load is large, it rotates slowly relative to the rotating shaft 14.

The photographic film 4 transferred by the drive sprocket 30 is pressed against the outer periphery of the take-up spool 2 by guide rollers 9 and 10, and its perforation 4a engages with the pawl 3 for autoloading. will be carried out. Thereafter, the photographic film 4 is pressed down by the guide rollers 9 and 11, so that the photographic film 4 pulled out from the cartridge is wound around the outer periphery of the take-up spool 2 without loosening. Furthermore, drive sprocket 30
The amount of winding of the take-up spool 2 is greater than the amount of photographic film 4 transferred, and this difference is absorbed by the cylindrical leaf spring 19 slipping on the outer periphery of the spool shaft 13.

During winding of the photographic film 4, the driven sprocket 62 is rotated by the photographic film 4, and the pin 63 provided on the driven sprocket 62 turns on the film travel detection switch S2 only eight times per frame. . As a result, the differentiating circuit 94 outputs a pulse signal to blink the lamp 95 to display the film running state, and also turns the transistor 93 on and off. This transistor 9
3, the capacitor 87 repeats charging and discharging to reset the forward rotation timer circuit at regular intervals. Therefore, since the forward rotation relay 91 remains energized, the motor 1 continues to rotate in the forward direction.

Gear 46 that rotates when winding photographic film 4
The control cam 47 and the shutter set cam 48, which are provided coaxially with this, are rotated once. As shown in FIG. 2, while the shutter set cam 48 rotates 180 degrees, it pivots the shutter set lever 68 counterclockwise, and at its free end the shutter drive lever 7 is rotated.
Press the bent portion 70a of the shutter drive lever 7.
Move 0 to the right. This shutter drive lever 70 sets the shutter when moving rightward, and is locked by a lever lever 79.
As the shutter set cam 48 rotates an additional 180 degrees, the shutter set lever 68 pivots clockwise and its free end separates from the shutter drive lever 70.

When the shutter drive lever 70 moves to the right, its vertical portion 70b pushes the bent portion 71a to move the interlocking lever 71 to the right against the spring 72. As the locking lever 73 moves to the right as a result of the interlocking lever 71, its free end enters the vertical groove 76b, allowing the release lever 75 to be pressed down. In addition, the interlocking lever 71
energizes the spring 67 to bias the control lever 65 counterclockwise, and presses the protrusion 65a against the outer peripheral edge of the control cam 47.

When the control cam 47 rotates once together with the shutter set cam 48, the control lever 65 is rotated counterclockwise by the spring 67, and the protrusion 6
5a enters the notch 47a. When the control lever 65 is rotated, the frame advance switch S3 is switched to contact b, and it is detected that one frame of the photographic film 4 has been wound.

Since the intermittent feed shaft 36 rotates once while the photographic film 4 is wound up for one frame, the ratchet wheel 37
Send only one pitch. This ratchet wheel 37 rotates together with the counter disc 39, so that the dot mark indicating the blank feed piece coincides with the index 40.

In this embodiment, there are three jump-feeding pieces, and during the transfer of the jump-feeding pieces, the pin 42 is pushed by the protrusion 39a of the counter disc 39, so the jump-feeding switch S1 is turned on. . Therefore, the comparator 88 indicates that the frame advance switch S3 is
Even if it is turned off, it remains in the operating state and continues to rotate the motor 1.

When winding of the third frame of the blank feed frame begins, the control cam 47 pushes the control lever 65 to forcibly push out the protrusion 65a from the notch 47a, and switches the frame feed switch S3 to contact a. As above,
One frame of the photographic film 4 is wound onto the take-up spool 2, and at the same time the control cam 47 and the shutter set cam 48 rotate once, and the counter disc 39 rotates one pitch. Note that since the shutter drive lever 70 is in the set state, the shutter set cam 48 simply rotates once.

After empty-feeding three frames in this way, the winding of the first frame begins. During this winding, the pin 42 comes off from the protrusion 39a and the idle feed switch S1 is activated.
Turn off. However, since frame advance switch S3 is ON during winding, comparator 8
8 remains in operation. When winding of the first frame is completed, the control lever 65 is rotated to turn off the frame advance switch S3. When this frame advance switch S3 is turned OFF, no voltage is applied to the comparator 88, and the forward rotation relay 91 is cut off. As a result, the forward rotation relay switch S4 is switched to the contact point b, so that electrical braking is applied and the rotation of the motor 1 suddenly stops.

As described above, when the release lever 75 is pressed down, the shutter drive lever 70 moves to the left to operate the shutter and photograph the first frame. When the shutter drive lever 70 returns, the control lever 65 is rotated clockwise and the frame advance switch S
Turn on 3. This frame advance switch S3
When turned ON, the forward rotation relay 91 is energized, and the motor 1 is rotated again to wind the photographic film 4 by one frame. Therefore, from the first frame onward, when the shutter release is performed and the photographing is completed, the motor 1 rotates forward and winds the photographic film 4 by one frame.
At the same time, set the shutter.

If the loaded cartridge takes 36 shots, normally you will not be able to pull out photographic film 4 from the cartridge in the middle of winding the 37th frame.
The motor 1 rotates freely due to the friction of the spring 18. In this case, since the photographic film 4 stops running, no pulse signal is output from the differentiating circuit 94. Therefore, capacitor 87
Since is continuously charged, the voltage at point A rises to the voltage at point B after a time t, which is shorter than one frame, has elapsed.

As shown in FIG. 6, when time t has elapsed after the film stopped running, the comparator 88 is reversed and its output terminal becomes "H", the forward rotation relay 91 is cut off, and the motor 1 is stopped. . In this case, since the frame advance switch S3 is ON, when the forward rotation relay switch S4 leaves contact point a, the potential at point Q becomes positive. As a result, the comparator 98 becomes operational, and its output terminal becomes "L". When the output terminal of the comparator 98 becomes "L", the reversing relay 101 is energized and the reversing relay switch S5 is switched from contact b to contact a. The motor 1 starts reversing because a reversing circuit is formed, and at the same time, the comparator 106 becomes active and its output terminal becomes "L".
become.

When motor 1 reverses, drive sprocket 30
rotates in the direction of the dotted line to unwind the photographic film 4 from the take-up spool 2 and transport it to the right. At the same time, the feed pawl 50 rotates the ratchet wheel 51 in the direction of the dotted line, and the rewind pawl 61 is rotated via the gear train. Since this rewind pawl 61 is connected to the spool of the cartridge, the drive sprocket 30
Rewind the photographic film 4 sent to you into the cartridge.

When rewinding the photographic film 4, the intermittent feed shaft 36 rotates to reverse the counter disk 39 one pitch at a time. Further, the control cam 47 and the shutter set cam 48 are also reversely operated in the same manner as in the above-described idle feed to set the shutter drive lever 70.

When the photographic film 4 is rewound, the differential circuit 9
A pulse signal is output from transistor 10.
7 is turned ON at a predetermined period. Therefore, since the capacitor 103 is alternately charged and discharged, the output terminal of the comparator 106 is set to "L".
is maintained.

When the rewinding of the photographic film 4 is almost completed, the perforation 4a is released from the driven sprocket 62.
comes off and the rotation of the driven sprocket 62 stops. Since the differentiating circuit 94 no longer generates a pulse signal, the lamp 95 stops blinking and the transistor 107 is turned off. capacitor 1
03 is charged with an approximately constant current, so C
When the voltage at the point rises to the voltage at point D, the output terminal of the comparator 106 is inverted to "H". However, the comparator 198 is connected to the frame advance switch S.
3 is ON and its output terminal is "L", so the reversing relay 101 continues to be energized. Then, the frame advance switch S3
When turned off, the comparator 98 becomes inactive. Since the capacitor 96 is immediately discharged, the output terminal of the comparator 98 becomes "H" and the reversing relay 101 is cut off.

When this reversing relay 101 is cut off, the reversing relay switch S5 switches to contact b and the motor 1 stops rotating in reverse. At this time, the shutter drive lever 70 is set, and the control cam 7
The protruding portion 65 of the control lever 65 is attached to the notch 47a of 7.
It is now in a state where a has entered.

When the power source 85 is consumed due to use, the rotation of the motor 1 stops during winding. When the reversing circuit is formed, since the load on the motor 1 is smaller during rewinding, reversing is started. Therefore, when the power supply voltage decreases, transistor 109 turns on.
Therefore, the lamp 95 lights up continuously to indicate that the motor 1 is stopped. At the same time, the transistor 93 is turned on, so that the forward rotation timer circuit, which determines the running state of the film during winding, is reset. Therefore, the motor 1 is stopped with the normal rotation circuit formed.

In the present invention having the above configuration, since the forward rotation timer circuit is reset when the power supply voltage drops, it is possible to prevent the photographic film from being rewound during photography.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the camera winding mechanism, Fig. 2 is a perspective view showing the motor control mechanism, Fig. 3 is a circuit diagram showing the motor control circuit, and Fig. 4 is a circuit showing an embodiment of the voltage detection circuit. 5 is a timing chart during winding, FIG. 6 is a timing chart during rewinding, and FIG. 7 is a timing chart showing the reset state of the forward rotation timer circuit. 1... Motor, 2... Take-up spool, 4... Photographic film, 4a... Perflation, 39
... Counter disk, 47 ... Control cam, 48 ...
Shutter set cam, 61... Rewind claw, 62...
... Driven sprocket, 65 ... Control lever, 68
... Shutter set lever, 70 ... Shutter drive lever, 71 ... Interlocking lever, 73 ... Locking lever, 75 ... Release lever, 91 ... Relay for forward rotation, 94 ... Differential circuit, 101 ... For reverse rotation Relay, 108...Voltage detection circuit, S1...Switch for blank feed, S2...Switch for detecting film running, S3...Switch for frame feed, S4...Relay switch for forward rotation, S5...Relay switch for reverse rotation, S6... Rewind switch.

Claims (1)

[Claims] 1 Connect a switching circuit in parallel with the capacitor, and when the photo film stops running, turn off the switching circuit and charge the capacitor.
In automatic rewind cameras that rewind the photographic film by reversing the motor when this capacitor is charged to a predetermined voltage, a voltage detection circuit is installed to detect a drop in the power supply voltage, and the power supply voltage is set to a predetermined value. The automatic rewind camera is characterized in that the switching circuit is turned ON to discharge the capacitor when the voltage drops to 0.