JPH0310497Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) This invention relates to a film feeding mechanism in an automatic winding camera, and more specifically, to a film feeding mechanism that can absorb phase differences due to fluctuations in film diameter during film feeding.

(Prior art) In cameras that automatically wind the film each time a photo is taken, a one-way clutch or a It is absorbed using a friction mechanism. However, the friction mechanism has the disadvantage that it requires a relatively large amount of strength and is difficult to manage. If the drive systems for the winding system and the winding system were made completely independent, the problem of the phase difference described above would not occur, but this would lead to the problem that the film feeding mechanism would become bulky.

(Objective) The present invention has been made in view of the above-mentioned drawbacks and problems, and it is an object of the present invention to provide a film feeding mechanism without friction loss.

The present invention stores the phase difference when feeding the film in one direction as the biasing force of the spring.
Release this when feeding the film to the other side,
It is characterized by being used as a biasing force for film winding.

Hereinafter, the present invention will be explained in detail using an example of an automatic winding camera in which all loaded film is wound onto a spool in advance and then rewound into a cartridge each time a photograph is taken.

In FIG. 1, reference numeral 1 indicates a spool as a first rotating body for winding the film, and reference numeral 2 indicates a cartridge claw as a second rotating member for winding the film. The cartridge claw 2 engages with a cartridge shaft 4 of a cartridge 3 storing a film. Further, reference numeral 5 indicates a drive motor which rotates forward or reverse depending on the mode, and reference numeral 6 indicates a sprocket that engages with the perforation of the film being fed. A spool gear 7 is fixed to the spool 1, a cartridge gear 8 is fixed to the cartridge pawl 2, a motor gear 9 is fixed to the drive motor 5, and a sprocket gear 10 is fixed to the sprocket 6. The spool gear 7 and the motor gear 9 are connected by a hoisting gear train 15 consisting of gears 11-14. Patrone gear 8 and sprocket gear 10 are connected by a rewinding gear train 23 consisting of gears 16 to 21 and a phase difference absorbing mechanism 22. A mode switching gear 24 is disposed between the sprocket gear 10 and the gear 14 so as to be movable in the axial direction to connect the two gears depending on the mode.

The gear 19 is a gear that is rotated as the sprocket 6 rotates, and is hereinafter referred to as a first phase difference gear. The gear 18 is a gear that is rotated as the patrone claw 2 rotates, and is hereinafter referred to as a second phase difference gear.

As shown in FIG.
The second disc 26 and the gear 19 are integrally connected with each other.
and a first disc 28 integrally connected by a shaft 27;
Phase difference spring 2 connecting both discs 26 and 28
It consists of 9. The upper end small diameter portion of the shaft 27 is rotatably fitted into the lower end bearing hole of the shaft 25 .
Therefore, the first and second phase difference gears 19 and 18 are arranged on the same axis. The phase difference spring 29 is arranged so as to wrap around a shaft 27 located between the discs 26 and 28, with one end 30 inserted into the hole 31 of the first disc 28 and the other end 30 inserted into the hole 31 of the first disc 28.
2 are respectively locked in the holes 33 of the second disc 26.

The present invention is configured as described above. below,
The effect will be explained. Patrone 3 is loaded,
When the back cover (not shown) is closed, the film feeding mode changes to the preliminary winding mode, and the drive motor 5 starts rotating the motor gear 9 in the direction of the solid arrow.
At this time, the mode switching gear 24 is retracted to a position where the sprocket gear 10 and the gear 14 are disengaged. The rotation of the motor gear 9 rotates the spool 1 in the direction of the solid line arrow via the hoisting gear train 15 and the spool gear 7. When the spool 1 rotates, the film inside the cartridge 3 (not shown)
is unwound while rotating the cartridge pawl 2 and sprocket 6 in the direction of the solid arrow, respectively.
It is wound onto spool 1. When the preliminary winding of the film is completed and the tension of the film reaches a predetermined value, the preliminary winding end detection member is activated and the drive motor 5 is turned off. Further, the mode switching gear 24 moves and meshes with the sprocket gear 10 and the gear 14, respectively. Since the mode switching gear 24 connects the drive system and the rewinding gear train 23, the film feeding mode is switched to the photographing mode. Thereafter, when a photographing operation is performed, the drive motor 5 rotates in the direction of the dashed arrow in response to the shutter travel completion signal, and the hoisting gear train 15 and sprocket 6
Then, the rewinding gear train 23 is rotated in the direction of the dashed arrow to rewind the film by one frame. After feeding one frame of film, the drive motor 5 is turned off.

In the preliminary winding mode, the film to be fed causes the sprocket 6 engaged with the perforation thereof to rotate in the direction of the solid line arrow, and also causes the cartridge shaft 4 to rotate. At this time, the amount of film fed and the rotation of the sprocket 6 are proportional. Therefore, the rotation of the first phase difference gear 19 rotated by the sprocket 6 is proportional to the amount of film fed.

On the other hand, the rotation of the cartridge shaft 4, that is, the cartridge claw 2, which rotates following the feeding of the film, is as follows.
It changes depending on the film winding diameter. Therefore, the second phase difference gear 1 that rotates in conjunction with the patrone claw 2
The rotation number 8 is not proportional to the amount of film fed. Therefore, in the early stage of the preliminary winding mode when the winding diameter of the film in the cartridge 3 is large, the first phase difference gear 19 and the second phase difference gear 18
Although the rotation is approximately the same, as the preliminary winding progresses and the winding diameter of the film decreases, the deviation gradually increases. That is, a difference in rotation speed, a so-called phase difference, occurs between the first phase difference gear 19 and the second phase difference gear 18. This phase difference can be clearly seen by the positions of the ends 30, 32 of the phase difference spring 29, which are locked at both ends to the first and second discs 28, 26.

As shown in FIG. 3, in the initial position of the preliminary winding mode, both ends 30 of the phase difference spring 29,
32 are positioned with a phase difference of angle θ1. Then, as the preliminary winding progresses, the first disc 2
8 (end 30) is the second disk 26 (end 32)
4, the ends 30 and 32 are positioned with a large phase difference as shown by the angle .theta.2 in FIG. That is, the phase difference between both ends of the phase difference spring 29, in other words, the phase difference between the first phase difference gear 19 and the second phase difference gear 18, is absorbed in the form of energy stored in the spring.

When a photograph is taken in the photographing mode, the drive motor is turned on and rotates in the direction of the dashed line arrow every time one frame is photographed, and the winding gear train 15, sprocket 6, rewinding gear train 23, and cartridge pawl 2 are moved along the dotted line. By rotating in the direction of the arrow, one frame of film is wound around the cartridge shaft 4 and then rewound. During this film rewinding operation, a phase difference occurs between the sprocket 6 and the cartridge shaft 4 as the film winding diameter of the shaft increases. In other words, as the cartridge shaft 4 becomes thicker, a phase difference arises between the first disc 28 and the second disc 26, and the second disc 26 becomes larger than the first disc 28. This will cause extra rotation. This phase difference between the two discs is absorbed by releasing the stored phase difference spring 29.

The release of the phase difference spring 29 not only serves to absorb the phase difference in the rewinding gear train, but also acts as an urging force for assisting the drive motor 5 in rewinding the film. That is, the rotation of the drive motor 5 rotates the sprocket 6 in the direction of the dashed arrow to feed the film in the rewinding direction, and also rotates the cartridge pawl 2 via the rewinding gear train 23. At this time, the first disc 28 included in the gear train 23 rotates the second disc 26 via the phase difference spring 29, and the spring 29 stores energy during preliminary winding. Therefore, the second disk 26 is energized by the release of the force. The biasing of the second disc 26 means biasing the rotation of the gear train extending from the disc to the cartridge pawl 2, which assists the driving force for rewinding the film.

Next, the extent of the phase difference generated between the sprocket 6 and the cartridge shaft 4 will be explained using specific numerical values.

When the diameter of the cartridge shaft is 2×r ₀ Film thickness d Film length l The mutual length of the spool chamber and the cartridge chamber L L, the amount of film fed by the cartridge shaft is: 1st rotation 2πr ₀ 2nd rotation 2πr ₀ +2π(r ₀ +d) 3rd rotation 2πr ₀ +2π(r ₀ +d) + 2π(r ₀ +2d) 〓 Nth rotation 2πr ₀ +...+2π(r ₀ + (N-1)d), and the cartridge feed amount PF is expressed as PF=2πN(r ₀ +N-1/2d) (1).

On the other hand, the film feed amount SF by sprocket
is expressed as SF=2πR ₀ n (2), when the sprocket diameter is 2×R ₀ and the sprocket rotates n times.

Since the amount of film fed is the same at any position, the following equation (3) holds true from equations (1) and (2) above.

2πR ₀ n=2πN(r ₀ +N−1/2d) (3) Here, specific numerical values will be given as examples. Needless to say, this value varies depending on the camera model.

Sprocket circumference 2πR ₀ ...38.00mm Patrone shaft diameter 2r ₀ ...11.50mm Film thickness d...0.14mm Film length (36 shots) l...1650.00mm Mutual length of spool chamber and cartridge chamber L
...When it is 51.00mm, substituting this into the above equation (3) gives n=0.01157N ² +0.9392N ...(4). On the other hand, the number of revolutions n of the sprocket required to feed the entire length of the film is 38n=l−L=1650−51 n=42.08 (5). From equations (4) and (5), the rotation speed N of the cartridge shaft is N=32.11. Therefore, in the case of a 36-shot film, n-N=42.08-32.11=9.97≈10, resulting in a phase difference of about 10 rotations.

The phase difference 10 (rotation) obtained from the above calculation is
This is a numerical value when the rewinding gear train 23 is constituted by a constant velocity gear train. In other words, when a rewinding gear train is configured with a constant velocity gear train, the phase difference spring 29 must be displaced and energized by an amount necessary to absorb the phase difference of 10 rotations. In this case, the spring must be wound around the shaft 27 many times, which increases the space occupied by the spring, making it impractical.

Therefore, the sprocket 6 and the first phase difference gear 19
Sprocket gear 10 and gear 2 arranged between
1 and 20 are composed of reduction gear trains, and the cartridge gear 8 and gears 16 and 17 arranged between the cartridge pawl 2 and the second phase difference gear 18 are composed of reduction gear trains, and the first , second discs 28, 26
By rotating , it is possible to set the phase difference between both disks within one rotation. This is advantageous in that the installation space for the phase difference spring can be made smaller.
Note that the phase difference of 10 rotations obtained in the above calculation formula is for a film taken with 36 shots, and the phase difference for a film with a smaller number of shots is naturally a value smaller than 10.

Furthermore, the embodiment described above is applied to a type of camera that performs preliminary winding and rewinds the film one frame at a time into the cartridge each time a photograph is taken. This spring is stored and used as a biasing force for rewinding the film by releasing it each time a photo is taken.However, in this invention, the film is wound onto a spool each time a photo is taken, and after the photo is taken, the spring is released. Of course, this invention may also be applied to a type of camera in which the film is continuously rewound onto a cartridge. Further, in the illustrated embodiment, the film is wound by a spool drive, but the film may be wound by a sprocket drive. In this case, since a phase difference will occur between the sprocket and the spool, the phase difference absorbing mechanism 22 will be incorporated into the hoisting gear train 15.

(Effects) As described above, according to the present invention, the phase difference spring that absorbs the phase difference requires only a small amount of force, and there is no friction loss as in the conventional case.
The force stored in the spring when the film is wound in one direction is released when the film is wound in the other direction, thereby energizing the film feeding at this time. In particular, in the case of a camera that performs preliminary winding, if the phase difference spring is stored in the preliminary winding mode and then released in the shooting mode in which the drive motor is repeatedly turned on and off, the motor start-up becomes sensitive. Moreover, it greatly contributes to saving starting power.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts showing an embodiment of the present invention;
Figure 2 is a partially cutaway front view of the phase difference absorption mechanism;
This figure and FIG. 4 are action diagrams showing changes in phase difference. 1... Spool, 2... Patrone claw, 3...
Patrone, 5... Drive motor, 6... Sprocket, 15... Hoisting gear train, 18... Second phase difference gear, 19... First phase difference gear, 22... Phase difference absorption mechanism, 23... Rewinding gear train, 29...phase difference spring.

Claims (1)

[Scope of utility model registration request] A sprocket that rotates in conjunction with the feeding of the film, a first phase difference gear that rotates as the sprocket rotates, a first rotating body that winds the film, and a second rotating body that winds the film. a second phase difference gear that is arranged on the same axis as the first phase difference gear and is rotated as the second rotating body rotates; a second phase difference gear that is arranged on the same axis as the first phase difference gear; It is hung between the phase difference gear,
Energy is stored when the film is fed in the direction in which it is wound around the first rotating body, and the film is fed to the second rotating body.
A film feeding mechanism in an automatic film winding camera, which comprises a phase difference spring that is released when the film is fed in the direction of being wound onto a rotating body.