JPH08339013A - Motor-driven winding device for camera - Google Patents

Abstract

PURPOSE: To lighten load imposed on a power source by a motor and to secure film stopping accuracy. CONSTITUTION: This device is equipped with a film winding mechanism 5 winding photographic film, a 1st motor 4 being the driving source of a film winding mechanism, a camera mechanism 3 constituting the movable part of a camera other than the film winding mechanism, a 2nd motor 2 being the driving source of a camera mechanism, a controller which controls the driving of the 1st and the 2nd motors 4 and 2, and a counting means counting the number of frames of photographic film and outputting a signal in accordance with the number of photographed frames. The controller changes the time for starting the 1st motor 4 after starting the 2nd motor 2 and driving speed of driving the 1st motor 4 in accordace with output from the counting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric winding device for a camera, which winds a film electrically.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional camera 1 in which electric driving of a camera mechanism such as a shutter and electric driving of film winding are performed by separate motors.

The motor 2 drives the shutter 3 and the like through a deceleration mechanism (not shown). The motor 4 drives the film take-up spool 5 via a reduction mechanism (not shown). 6 is a film cartridge, and 10 is a film drawn from the film cartridge 6.

As the film 10 is wound on the spool 5, the winding diameter of the spool 5 changes, and the film winding diameter increases from the initial diameter 11a to the diameter 11b. Since the film pulling force F from the cartridge 6 is almost constant, the film winding torque (= radius R of film winding diameter × R)
F) increases according to the number of wound frames. If the gear ratio K of the film winding mechanism is constant, the load torque T (= C × R × F / K, where C is a coefficient) on the motor 4 increases.

FIG. 2 shows the characteristics of the motor 4. The horizontal axis represents the load torque T, and the vertical axis represents the motor output P. When the load torque at the beginning of film winding is T1 (output P1), the load torque becomes T2 (output P2) toward the end of the film, and the output increases. The film winding time t is a value (= W / P) obtained by dividing the film winding work W (= F × length of one frame of film) by the output P. However, while the film winding work W is almost constant, Since the output P increases as described above, the winding time becomes shorter as the film winding progresses.

FIG. 3 shows the current I1 of the motor 2 for driving the shutter and the current I2 of the motor 4 for driving the film winding. The motor 4 is started after a lapse of a predetermined time t3 from the start of the motor 2. This is to prevent the inrush currents of the two from overlapping and increasing the load on the power supply.

The driving time t1 of the motor 2 is not so much influenced by the number of film windings. On the other hand, the film winding time t2 per unit length varies from the film winding start time t2,1 to the film winding time t2,2 as described above. In order to shorten the shooting interval, it is desired that both are completed at substantially the same timing, so the gear ratio must be set as shown in FIG.

[0008]

In this way, at the end of the film, the film winding is finished earlier, and the end of driving the shutter or the like is awaited, which is a waste of time. If the winding time has a margin, it is preferable to shift the timing of the inrush current as much as possible in terms of the load on the power supply. Alternatively, in order to secure the film stopping accuracy, it is preferable to drive the film for as long as possible.

The present invention has been made in view of the above problems, and reduces the load applied to the power supply by the motor, and
The purpose is to ensure film stop accuracy.

[0010]

In order to achieve this object, a first aspect of the present invention relates to a film winding mechanism (5) for winding a photographic film, a first motor (4) as a driving source of the film winding mechanism, A camera mechanism (3) constituting a movable part of the camera other than the film winding mechanism, a second motor (2) serving as a drive source of the camera mechanism, and a first motor is activated after a set time has elapsed since the second motor was activated. It comprises a timer device (21) and a counting means (23) for counting the number of frames of the photographic film and outputting a signal according to the number of frames already taken, and the timer device is set according to the output of the counting means. It is configured to change time.

A second invention is a film winding mechanism (5) for winding a photographic film, a first motor (4) as a drive source of the film winding mechanism, and a camera mechanism constituting a movable part of the camera other than the film winding mechanism. (3)
A second motor (2) as a drive source for the camera mechanism, and a drive speed control means (2) for changing the drive speed of the first motor.
1) and a counting means (23) which counts the number of frames of the photographic film and outputs a signal according to the number of frames already photographed, and the drive speed control means controls the drive speed according to the output of the counting means. Is configured to change.

[0012]

In the electric hoisting device for a camera having the above structure, the timing of inrush current flow is shifted as much as possible by changing the timing of starting the film hoisting motor according to the number of take-up frames, and the load on the power source is reduced. Can be reduced. Further, by changing the drive speed of the film winding motor according to the number of winding frames, the film winding motor can be driven at the lowest speed possible and the film stop accuracy can be secured.

[0013]

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

FIG. 5 is a block connection diagram showing an embodiment of an electric hoisting device for a camera according to the present invention.

In FIG. 5, the control unit 21 controls the entire apparatus. The power supply 22 is a power source of the entire apparatus, and the motors 2 and 4 are supplied with power via motor control units 25 and 26, respectively. The frame number counting unit 23
The number of wound frames of the film 10 is optically or mechanically counted, and a signal corresponding to the number of photographed frames is output to the control unit 21. The film movement amount detection unit 24 detects the movement amount of the film and outputs a signal corresponding to the winding amount for one frame to the control unit 21. The motor control unit 25 controls driving of the motor 2. The motor control unit 26 controls driving of the motor 4.

The control unit 21 changes the time difference between the start-up of the motor 2 and the motor 4 based on the signal corresponding to the number of photographed frames supplied from the frame number counting unit 23. That is, FIG.
As shown in (a), as the number of frames increases from N1 to N3, the control unit 21 changes the delay time from t3,1 to t3.
The length is increased to 3 and 3 so that the operation completion of the motor 4 is controlled to be almost the same as the operation completion of the motor 2.

When the film winding amount reaches a predetermined value, the motor 4 is driven based on the signal corresponding to the winding amount for one frame supplied from the film movement amount detecting section 24. The full drive duty is changed to the mode in which the speed is reduced by PWM control. That is, as shown in FIG. 4B, as the number of frames increases from N1 to N3, the control unit 21 changes the duty of PWM control from D1 to D3 to decelerate the speed. As a result, the control unit 21
Control to ensure film stop accuracy.

In the embodiment, the case where the frame number counting unit 23 and the film movement amount detecting unit 24 are independently provided has been described, but the film movement amount detecting unit 24 may also be used as the frame number counting unit 23. it can. Further, in the embodiment, the drive duty is changed as a method of changing the drive speed, but the motor drive speed may be changed by changing the drive voltage or the drive current.

[0019]

As described above, according to the electric winding apparatus for a camera of the present invention, the timing of starting the film winding motor is changed according to the number of winding frames, so that the timing of the inrush current can be changed. The load on the power source can be reduced by shifting as much as possible. Further, since the drive duty of the film winding motor is changed according to the number of winding frames, it is possible to drive the film winding motor at a speed as low as possible to ensure the film stop accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a conventional electric hoisting device for a camera according to the present invention.

FIG. 2 is a characteristic diagram showing an example of a conventional electric hoisting device for a camera according to the present invention.

FIG. 3 is a characteristic diagram showing an example of a conventional electric hoisting device for a camera.

FIG. 4 is a characteristic diagram showing an example of an electric hoisting device for a camera according to the present invention.

FIG. 5 is a block connection diagram showing an example of an electric hoisting device for a camera according to the present invention.

[Explanation of symbols]

 1 camera 2 motor 3 shutter 4 motor 5 spool 6 film cartridge 10 film 21 control unit 22 power supply 23 frame number counting unit 24 film movement amount detection unit 25 motor control unit 26 motor control unit

Claims (3)

[Claims] 1. A film winding mechanism for winding a photographic film, a first motor as a drive source for the film winding mechanism, a camera mechanism constituting a movable part of a camera other than the film winding mechanism, and a driving mechanism for the camera mechanism. A second motor as a power source, a timer device that starts the first motor after a set time has elapsed from the start of the second motor, the number of frames of the photographic film is counted, and a signal according to the number of frames already photographed is output. An electric hoisting device for a camera, characterized in that the timer device changes the set time according to the output of the counting device. 2. A film winding mechanism for winding a photographic film, a first motor as a drive source for the film winding mechanism, a camera mechanism constituting a movable part of the camera other than the film winding mechanism, and a drive for the camera mechanism. A second motor as a power source, a drive speed control means for changing the drive speed of the first motor, and a counting means for counting the number of frames of the photographic film and outputting a signal according to the number of frames taken. An electric hoisting device for a camera, wherein the drive speed control means changes the drive speed according to the output of the counting means. 3. The method according to claim 2, wherein the drive speed is changed by a first mode in which the motor is driven at a first drive speed and a second mode in which the motor is driven at a drive speed lower than the drive speed in the first mode. An electric hoisting device for a camera, characterized in that the mode is changed.