JPS6053861B2 - Motor drive control circuit in camera motor drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a motor drive control circuit in a motor drive device for a camera, and more specifically, when an operation switch is closed, the motor drive circuit is operated to rotate the motor, thereby performing a release operation and a film release operation. The present invention relates to a motor drive control circuit in a camera motor drive device that automatically and continuously performs one cycle of hoisting operation.

By pressing the operation button and closing the operation switch, the motor rotates and the camera's release mechanism is activated to expose the film. After the exposure is complete, the selector switch automatically switches to apply the rotational force of the motor. A motor drive device that winds exposed film by transmitting information to a film winding mechanism, i.e., a camera motor drive that automatically performs one cycle of release operation and film winding operation in succession. The device is well known. However, this conventional motor drive device has the disadvantage that the motor does not immediately stop rotating when the film is finished, and the perforation portion of the film is cut.

In other words, during film winding, when the photographic film is finished and there is no more film to wind, the film winding mechanism stops its operation, so the changeover switch automatically switches from the winding side terminal to the release side terminal as soon as possible. However, at this time, the motor drive circuit is still operating, so the motor does not stop immediately, and the drive device is switched to the next step.
Entering the cycle, the selector switch switches from the release side terminal to the winding side terminal, and immediately returns from the winding side terminal to the release side terminal, causing a chattering operation. Also, because the selector switch switches to the winding side terminal for a short time, the motor tries to forcefully drive the film winding mechanism, causing the film transport sprocket wheel in the mechanism to rotate slightly. , which will tear the perforation part of the film. Further, if the film winding mechanism is driven even more forcefully, there is a risk that the film will be cut. SUMMARY OF THE INVENTION In order to eliminate such conventional drawbacks, an object of the present invention is to provide a conventional motor drive circuit with a control circuit that turns off a motor energizing switching element of the motor drive circuit at the end of a film. Therefore, it is an object of the present invention to provide a motor drive control circuit for a motor drive device for a camera, which prevents the chattering operation of the drive circuit which causes the film to run out, and also instantaneously stops the rotation of the motor.

EMBODIMENT OF THE INVENTION Hereinafter, this invention will be explained in detail by the embodiment of illustration.

The electric circuit shown in FIG. 1 is a motor drive control circuit showing a first embodiment of the present invention.

This circuit consists of a motor drive circuit, a motor stop circuit,
It consists of a changeover switch, a brake switch, and a control circuit. Note that this embodiment is for one-frame photography.

The motor drive circuit is connected to both ends of a power source E via a power switch SWl.

A series circuit consisting of an operation switch SW2, a capacitor Cl, and a resistor R2, a series circuit consisting of a driving motor M, a transistor Tr3 which is a switching element for energizing the motor, and a transistor Trl, which are also connected via the power switch SW1. Resistance RO, R3, R,,
It consists of a diode D1 and a brake switch SW4. The resistor R1 is connected in parallel to the series circuit of the capacitor C1 and the resistor R2, and the diode D1 is connected in parallel to the resistor R2. Also,
One end of the resistor R3 is connected to the connection point between the resistor R2 and the capacitor C1, and the other end is connected to the transistor T.
connected to the base of rl, and the above capacitor C1
In cooperation with the transistor Trl, an integrator circuit is formed which generates a starting voltage for driving the transistor Trl. The transistor Trl has an emitter connected to the transistor Tr3.
The collector is connected to a movable contact piece A of a changeover switch SW3, which will be described later.
The resistor R5 has one end connected to the movable contact piece A, and the other end connected to one fixed terminal B of the brake switch SW4. It is connected to the. This brake switch SW4 is designed to be switched in conjunction with a movable reflector (not shown) in a single-lens reflex camera, and when the movable reflector is lowered, its movable contact piece A is switched. is one fixed terminal B. When the movable reflector is flipped up by the release operation for photographing, the movable contact piece is switched to the other fixed terminal C. It is starting to switch to . The fixed terminal CO is connected to the collector of the transistor Tr3, which is connected to the motor M. The motor stop circuit is
A brake switching element transistor Tr4 connected in parallel to the motor M, a transistor Tr5 supplying a base voltage to this transistor Tr through a resistor R7, a resistor R6, and capacitors C2 and C.
3. Diodes D3, D4, movable contact piece A of the switch SW4.

, fixed terminal C. It is made up of. The transistor Tr4 has its emitter connected to a terminal of the motor M connected to the positive side of the power source E, and its collector connected to a terminal of the motor M connected to the transistor Tr3. In addition, the base is a transistor T
It is connected to the collector of r5 through a resistor R7. The emitter of the transistor Tr5 is connected to the negative terminal of the power source E, and a diode D4 is connected between the emitter and the base. Further, the capacitor C3 and the resistor R6 are connected in series to the base and the release side terminal B of the changeover switch SW3, which will be described later. Note that a capacitor C2 is connected in parallel to both ends of the motor M. Also, the other fixed terminal C of the brake switch SW4. is connected to the connection point between the motor M and the collector of the transistor Tr3, and a diode D is connected to the connection point between the resistor R6 and the capacitor C3 and the collector of the transistor Tr3.
3 is connected. Next, the control circuit is according to the present invention, and in this embodiment, transistors Tr2,
The output stop circuit includes a resistor R4 and a diode D2.

The transistor Tr2 has its collector connected to the connection point between the capacitor C1 and the resistor R2, its emitter connected to the negative electrode of the power supply E, and its base connected to the winding side of the changeover switch SW3 via the resistor R4. Connected to terminal C. Further, a diode D2 is connected between the winding side terminal C and the base of the transistor Tr3. The output stop circuit configured in this way rapidly charges the capacitor C1 during film winding, and at the moment the selector switch SW3 switches from the winding side terminal C to the release side terminal B. , serves to cut off the input to the transistor Tr3, which is a switching element for energizing the motor, and turn off the transistor Tr3.

Also, the time constant of the integration circuit of the capacitor C1 and the resistor R3 is such that the transistor Tr during the winding time of the release, etc.
It is set to turn off.

Therefore, the transistor Trl remains on during the integration time of the capacitor C1. However, at the end of the film, the movable contact piece A of the changeover switch SW3 is in contact with the winding side terminal C for a short time, so the transistor T
The on time of rl becomes longer. This drawback is solved in this example.
This problem is solved by the above output stop circuit. As mentioned above,
The electric circuit in this embodiment is configured.

The changeover switch SW3 in this electric circuit is
The switch is disposed in a drive mechanism of a motor drive device, which will be described next, and is adapted to be switched by a switch changeover lever as the motor rotates. The drive mechanism of the motor drive device is constructed as shown in FIG.

In FIG. 3, a motor M is connected to the upper right portion of the board 1 via a gear case 2. As shown in FIG.

A shaft 4 is rotatably provided in the right center portion of the board 1, and this shaft 4 is connected to an output gear (not shown) of a motor M via a gear train (not shown) in the gear case 2. ) is operatively connected to. When the motor M rotates, it rotates in the direction of arrow a. A sun gear 5 and a base of a rotary arm 6 are connected to the shaft 4 by friction coupling means (not shown), respectively.
A planetary gear 8 meshing with the sun gear 5 is rotatably mounted on a shaft 7 implanted in the free end of the rotary arm 6.

A ring-shaped command member is further fitted onto the shaft 7. Note that the frictional coupling means can be omitted if there is no particular problem. At the center of the board 1 is a shaft 1.
0 is rotatably provided on this shaft 10, when the planetary gear 8 is driven by the sun gear 5 and revolves around the sun gear 5, a part of the planetary gear 8 on its orbit 01 is rotated. , a film winding gear 11 that meshes with this gear 8 is mounted.

A gear 1 is located above the gear 11 on the shaft 10.
2 and a pawl member 13 are each integrally attached to the gear 11. The claw member 13 has engaging claws 13a, 13 on its upper part.
b, and insert the engaging claw 1 into the film spool inside the camera body.
3a and 13b are engaged and the film is wound according to the rotation of the gear 11. On the right side of the gears 11 and 12 in FIG.
1 and a gear 12, and both levers 14 and 15 are rotated by shafts 16 and 17 arranged in parallel at the center of the lower edge of the substrate 1, respectively. freely supported.

The lower side of the curved free end of the switch changeover lever 14 forms a pressed portion 14a corresponding to the orbit 01 of the command member 9, and the base of this pressed portion 14a is connected to the planetary gear 8. A stepped recess 14b is formed in a portion corresponding to the position where the film winding gear 11 meshes with the film winding gear 11.

Furthermore, insulating pins 3a and 3b are implanted on the top surface of the tip of the switch changeover ν bar 14 to hold the movable contact piece A of the changeover switch SW3. And selector switch S
W3 is fixed to the substrate 1, and fixed terminals B and C are respectively disposed on both sides of a movable contact piece A whose tips are held between the insulating pins 3a and 3b. A torsion spring 20 is fitted into the shaft 16 of the switch changeover lever 14, and one end 20a of this torsion spring 20 is fixed to a pin 21 fixed to the board 1, and the other end 20b is fixed to this lever 14. They are each hung on a planted pin 22. Therefore, the lever 14 is given a clockwise rotational habit about the shaft 16 by the torsion spring 20. and,
This rotation range is limited to a range in which the other arm 14c of the lever 14 engages with the pin 21 fixed to the board 1 (
(See Figures 4 and 5). The free end of the shutter release spar 15 extends to a position corresponding to the orbit 01 of the command member 9 and serves as a pressed portion 15a, and a pushing arm 15b extends from the left side of its base. has been done. A release arm 18 is rotatably attached to a portion of the shaft 17 of the shutter release spar 15 above the lever 15, passing over the upper left of the gear 12 and curved to the right. axis 1
A pair of torsion springs 19 and 24 are fitted in 7, and one end of one torsion spring 19 is hung on the fixing pin 21, and the other end is hung on the push arm 15b of the shutter release spar 15. , this shutter release spur 15 is given a clockwise rotational habit about the shaft 17. One end of the other torsion spring 24 is hung on a pin 25 implanted in the shutter release spar 15, and the other end is hung on an arm portion 18a extending on the left side near the base of the release arm 18. , as shown in FIG.
and are elastically connected together. Note that the rotation range of both is determined by the contact portion 1 provided on the extended arm portion 18a of the release arm 18.
8b is regulated by coming into contact with a pin 26 fixed to the substrate 1. A release pin 27 is fixed to the free end of the release arm 18.
As will be described later, when the release arm 18 swings, it moves to the chain line position 27A (this position is indicated by a solid line in FIG. 4), and the shutter release mechanism of the camera body (not shown) ) to drive. In this way, the drive mechanism of the motor drive device is configured.

Next, the operation of the electric circuit shown in FIG. 1 and the drive mechanism shown in FIG. 3 will be explained with reference to FIG. 1 and FIGS. 3 to 5.

First, close the power switch SWl, and then close the operation switch SW1.
2, the shutter starts to be released.

That is, when the operation switch SW2 is closed, the starting voltage is applied to the base of the transistor Trl by the integrating circuit of the capacitor Cl and the resistor R2, so the transistor Trl is turned on and supplies the base voltage to the transistor Tr3. The transistor Tr3 becomes conductive, and the motor M starts driving. When the motor M starts rotating, the sun gear 5 and rotating arm 6 shown in FIG. 3 start rotating and moving in the direction of arrow a.

When the rotary arm 6 moves in the direction of arrow a, the pressed portion 15a of the shutter release spar 15 is pushed upward by the command member 9, so that the shutter release spar 15 is moved around the support shaft 17 by the spring 19. rotates counterclockwise against the elastic force of When this rotates, the extending arm 18a also moves following the rotation of the pushing arm 15b due to the elasticity of the spring 24, so the release arm 18 also rotates counterclockwise around the support shaft 17. do. When this rotates, the release pin 27 moves to the chain line position 27A, thereby releasing the shutter release mechanism of the camera body and flipping up the movable reflector. When the movable reflector jumps up, the brake switch SW
4, movable contact piece A. is fixed terminal B. The motor switches from CO to CO and brakes motor M, causing motor M to suddenly stop. Moreover, this brake switch SW4 has fixed terminals 8 to C.

Immediately before switching to , the command member 9 separates from the pressed portion 14a as shown in FIG. The other arm 14c collides with the pin 21 and stops. When this rotates, the movable contact piece A of the changeover switch SW3 is switched from the release side terminal B to the winding side terminal C. Then, exposure is performed in a state in which the switches SW3 and SW4 are switched from the terminals B and BO to the terminals C and CO, respectively, as described above.

Of course, in this state, the transistor Tr3 is in the off state.Next, when the exposure is finished and the movable reflector is lowered, the brake switch SW4 has its movable contact piece connected to the fixed terminal C.

From B. Switch to . When this is switched, since the changeover switch SW3 has been switched to the winding side terminal C, the transistor Tr3 receives a pulse from the power supply E.
, an operating voltage is applied through the diode D2. When the movable reflector descends, the shutter release spar 15, release arm 18, and release pin 27, which were in the operating position shown in FIG. 4, are moved to the position shown in FIG.
Restore to the initial state of the diagram.

Then, when an operating voltage is applied to the transistor Tr3 through the resistor R5 and the diode D2, the transistor Tr3 becomes conductive again, rotates the motor M, and now performs the film winding operation.

That is, when the motor M rotates, the sun gear 5 and the rotary arm 6, which were stationary at the position shown in FIG. 4, start rotating and moving again in the direction of the arrow a. The rotating arm 6 is approximately 31
When the fourth rotation position is reached, the planetary gear 8, which is rotating while meshing with the sun gear 5, meshes with the film winding gear 11. Further, at the same time as this is engaged, the command member 9 abuts against the stepped recess 14b of the switch changeover lever 14, and as shown in FIG. 5, the rotating arm 6 is temporarily stopped at this position. Therefore, in this state, the planetary gear 8 rotates the film winding gear 11 to wind up the film. Also,
When the film is wound, the shutter is also charged. When a predetermined amount of film is wound up after a regular winding time, the gear 11 together with the claw member 13 and the gear 12 stops rotating, and the planetary gear 8 starts to move due to its rotational force. . When this moves, the command member 9 and the rotary arm 6 also start moving in the direction of the arrow a, so that the command member 9 that has climbed over the step pushes the pressed part 14a of the switch changeover lever 14, which causes the command member 9 to move in the direction of arrow a. The lever 14 is a support shaft 16
is pushed up counterclockwise against the elasticity of the spring 20. When this is pushed up, selector switch SW3
, the movable contact piece A switches from the winding side terminal C to the release side terminal B. When this switches, resistor R6,
Since the operating voltage is applied to the base of the transistor Tr5 through the capacitor C, the transistor Tr5
5 becomes conductive, which causes the transistor Tr to conduct, applying a sudden brake to the motor M and stopping the motor. Therefore, the motor drive device automatically performs one cycle of release operation, exposure operation, and film winding operation and returns to the initial state. By the way, in a motor drive device that operates in this manner, if the film ends in the middle of being wound, the shaft 10 (see Figures 3 to 5) will stop rotating because there is no film to wind. Resulting in. Then, the planetary gear 8 rotated by the motor M cannot be hoisted even if it tries to wind it up, so it revolves due to its own rotational force, and the command member 9 climbs over the stepped recess 14b and closes the switch changeover lever 14. Rotate counterclockwise. When this rotates, the changeover switch SW3 switches from the film winding terminal C to the release terminal B. At this time, a motor stop circuit consisting of resistor R4, diodes D3, D4, capacitor C3, and transistors Tr, Tr5 works, but since the time constant circuit of capacitor C1 and resistor R3 is still integrating, transistor Trl Current is supplied to the base of the transistor Tr3 through the switch SW3, and the rotation of the motor M does not stop. Therefore, the changeover switch SW3 switches its movable contact A from the release side terminal B to the winding side terminal C again. This causes a chattering operation in which the terminal C is switched to the terminal B. This chattering operation occurs when the capacitor C is fully charged after the regular winding time has elapsed, and the transistor T
It stops when rl is turned off. However, if the output stop circuit which is the control circuit of the present invention is provided, after the exposure operation is finished, the movable contact piece A of the changeover switch SW3 is switched from the release side terminal B to the winding side terminal C. When the film winding operation begins, the base of transistor Tr2 has a
Forward voltage drop of diode D2 and transistor Tr
3 base-emitter voltage ■B! Since the voltage of the sum of l: is applied, the transistor Tr2 is turned on. When this turns on, the resistor R2 is shorted and the capacitor C1 is instantly and rapidly charged. Therefore,
The transistor Trl enters the OR state before the regular winding time elapses. However, since the base voltage is applied to the transistor Tr3 from the diode D2, the transistor Tr3 continues to be in the on state. In this state, when the film ends in the middle of winding and the movable contact piece A of the changeover switch SW returns from the winding side terminal C to the release side terminal B as described above, at that moment Since the current to diode D2 is also cut off, transistor T
r3 is turned off, the motor energizing circuit becomes non-conducting, and the motor stop circuit is activated to bring the motor M to an instantaneous sudden stop. Therefore, according to the present embodiment, the changeover switch SW3 does not cause a chattering operation, and the conventional drawbacks based on this can be eliminated.

FIG. 2 is an electrical circuit of a motor drive control circuit showing a second embodiment of the present invention. Note that this second embodiment is also for the case of single-frame photography. In the motor drive control circuit shown in FIG. 2, the transistor Tr6 and the thyristor SCR, which form the input circuit of the motor energization circuit, constitute a control circuit that instantaneously stops the motor. That is, a capacitor C4 and resistors R8 and R9 are connected in series to the operation switch SW2, and the gate of the thyristor SCR is connected to the connection point between the resistor R and the resistor R. The cathode of the SCR is connected to the negative electrode of the power source E, and the anode is connected to the base of the transistor Tr6 via a resistor RlO.
The emitter of the transistor Tr6 is connected to the release side terminal B of the changeover switch SW3, and a resistor Rll is connected to the emitter and base. Also,
The collector of this transistor Tr is connected through a resistor Rl2 to the base of a transistor Tr3, which is a switching element for energizing the motor. The winding terminal C of the changeover switch SW is connected to the base of the transistor Tr3 through a resistor Rl3.
Furthermore, the movable contact piece A of the switch SW3 is a fixed terminal B of the brake switch SW. It is connected to the. The control circuit is configured in this way, and this control circuit forms an input circuit of the motor energization circuit. In addition, the other configurations of this second embodiment, that is, the motor energizing circuit and motor stop circuit, changeover switch, brake switch, etc. other than the above-mentioned input circuit, are the same as those of the first embodiment shown in FIG. 1 above. The structure is as follows.

Therefore, a description of the structure will be omitted, and only the same reference numerals will be given to the members having the same function. Note that the capacitance of the capacitor C is smaller than that of the capacitor C1 in the first embodiment shown in FIG. supply is becoming available. According to the second embodiment configured in this way, when the operation switch SW2 is closed, the capacitor C4, the resistor R8,
A starting voltage is applied from the starting circuit of R to the gate of the thyristor SCR, which fires and makes the thyristor conductive.

When this becomes conductive, the operating voltage B is applied to the base of the transistor Tr6, so the transistor is turned on, and the transistor Tr3 is made conductive, thereby driving the motor M. Then, when the drive mechanism (see Fig. 3) of the motor drive device described above is activated, the shutter is released, and the movable contact piece A of the changeover switch SW3 is switched to the winding side terminal C, the thyristor Since the current supplied to the anode of the SCR and the transistor Tr6 is cut off, both are in an off state. Further, when the switch SW3 is switched to the winding side terminal C, current is supplied to the base of the transistor Tr3 through the resistor Rl3, so that the motor M continues to be energized. When the regular winding time has elapsed and a predetermined frame of film has been wound, the switch SW3 is switched to the release side terminal B, the motor stop circuit is activated, and the motor M is stopped. By the way, when the changeover switch SW3 is switched to the winding side terminal C and the film is being wound, when the film ends, the switch SW3 immediately switches off the release without the regular winding time elapsed. Switches to terminal B.

However, in this case, as mentioned above, the thyristor SC
Since the transistor Tr6 is off, the transistor Tr3 is completely off, and the motor stop circuit immediately operates to stop the motor M suddenly.
Therefore, also in this second embodiment, the changeover switch S
W3 can eliminate the conventional drawbacks without causing a chattering operation.

Furthermore, according to the electric circuit of the second embodiment, current is supplied to the gate of the thyristor SCR by closing the operation switch SW2, so that the method of pressing the push button of the operation switch SW2 is However, the present invention operates reliably, and there is no risk of malfunctions caused by so-called "pressing".As stated above, the present invention is able to operate reliably, as described at the beginning of the specification, compared to the conventional camera motor drive device. It is possible to provide a motor drive control circuit that completely eliminates the drawbacks of the above.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of a motor drive control circuit in a camera motor drive device showing a first embodiment of the present invention, and FIG. 2 is an electric circuit diagram of a motor drive control circuit in a camera motor drive device showing a second embodiment of the invention. An electrical circuit diagram of the motor drive control circuit, FIG. 3 is a plan view of the drive mechanism of the motor drive device that switches the changeover switch in the electric circuit, and FIGS. 4 and 5 show the operation of the drive mechanism shown in FIG. 3 above. It is a top view showing an aspect. SW2: Operation switch, M: Motor, SW3: Selector switch, B: Release end terminal, C: Winding end terminal, Tr3...
...Transistor (switching element for motor current supply), Tr4...Transistor (switching element for brake), Tr2...Transistor,
R4...Resistor, D2...Diode,
Tr6...Transistor, SCR...
Thyristor.

Claims (1)

[Claims] 1 An operation switch SW_2 for performing single-frame photography;
It has a release side terminal and a winding side terminal, and shifts to the winding side terminal in response to the shutter release operation, and changes to the release side terminal when the winding mechanism for one frame of film is completed or the winding mechanism stops when the film ends. Transfer switch SW_
3, and motor drive circuits Tr_1, SCR, and Tr_6 including switching elements that are interposed between the drive motor and the power source, and that are brought into conduction by a closing signal of the operation switch and generate an output signal; a motor energizing switching element Tr_3 that is electrically connected by an output signal from the motor drive circuit;
Control circuits Tr_2, SCR, and Tr cut off the output of the motor drive circuit by shifting the changeover switch to the hoisting side terminal.
_6, and an energizing path D_2 that conducts the motor energizing switching element Tr_3 through the terminal when the changeover switch moves from the release side terminal to the winding side terminal;
R_1_3; and a brake switching element Tr_4 which is connected to both ends of the drive motor and becomes conductive for a short time when the changeover switch is shifted to the release side terminal. control circuit.