JPH0244269Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a film feeding device for an autoloading camera. This invention relates to a film feeding device that is faster than the film winding speed of a spool and that rotates a sprocket intermittently.

Autoloading cameras with built-in motors have been known for a long time to automatically wind the film, and most of these autoloading cameras have a motor that continuously rotates the take-up spool and sprocket, The spool winding speed is designed to be higher than the film feeding speed by the sprocket. In a film feeding device with such a configuration, the film is pulled between the take-up spool and the sprocket, which can damage or tear the perforation that engages the protrusions on the sprocket. There is a problem with sticking. To prevent this, conventional autoloading cameras have a friction clutch on the take-up spool or a one-way clutch on the sprocket drive system, which increases the number of parts and costs. There were flaws.

Further, in an autoloading camera, when loading film, the film leader is transferred to the take-up chamber side by a sprocket and wound around the outer periphery of a take-up spool provided in the take-up chamber. This take-up spool has claws on its outer periphery and is designed to engage with the perforation of the film leader section transferred by the sprocket, but the above-mentioned take-up spool and sprocket rotate continuously. However, since both the film leader and the take-up spool move, there is a drawback that it is difficult for the perforation of the film leader to engage with the claw of the take-up spool.

The present invention was proposed in order to solve the above-mentioned drawbacks, and has a simple structure, and also enables the perforation of the film leader section and the claw of the take-up spool to engage quickly and reliably. It is an object of the present invention to provide a film feeding device that has the following features.

In order to achieve the above object, the present invention increases the film feeding speed of the sprocket relative to the winding speed of the take-up spool, and also rotates the sprocket intermittently so that the film is transported by a length less than one frame. This is what I did.

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

In FIG. 1, a gear 2 is fixed to an output shaft 1a of a motor 1, and the rotation of the gear 2 is transmitted to a gear 5 via a gear 3 and a gear 4 provided on the same axis. A connecting arm 6 is swingably supported on the shaft of the gear 5, and a gear 7 attached to the free end side of the connecting arm 6 meshes with the gear 5. This connecting arm 6 has two states, as shown in the figure, in which the gear 7 meshes with the gear 8 to transmit the rotation of the motor 1 to the take-up spool 9, and in the state shown in the figure, in which it rotates to the right and the gear 7 meshes with the gear 10. Then, the rotation of the motor 1 is transferred to the rewinding fork 11.

The take-up spool 9 has a plurality of claws 9a that engage with the perforation of the film leader section, and is connected to the gear 8 via a shaft 12, and rotates in the direction of the arrow shown by the solid line to complete the exposure. can be wound around the outer periphery of the take-up spool 9. The rotation of the gear 10 is transmitted to the gear 15 via gears 13 and 14. The rotation of this gear 15 is transmitted via a shaft 16 to a rewinding fork 11 connected to a shaft within the cartridge.

A gear 18 is provided coaxially with the gear 5, and this gear 18 meshes with a gear 19 having a small number of teeth. These gears 18 and 19 constitute a speed increasing mechanism, which rotates a notched gear 20 provided coaxially with the gear 19 at a high speed. Notched gear 20
In this case, some of the teeth are missing, and the gear 21 is rotated only during the period when the teeth are meshed with the gear 21, and the sprocket 22 provided coaxially with the gear 21 is rotated. In this embodiment, one rotation of the notched gear 20 rotates the sprocket 22 by two teeth at a high speed. The gear 21 meshes with a gear 23 having the same number of teeth, and a shutter set cam 24 and a control cam 25 for controlling frame feeding are provided coaxially with the gear 23.

Next, the operation of the present invention will be explained. Motor 1
When rotates in the direction shown by the solid line, gears 2 to 5,
A take-up spool 9 rotates continuously in the arrow direction via 7 and 8. On the other hand, the rotation of gear 5 is
8, 19, notched gears 20, and gears 21 to be transmitted to the sprocket 22.

Since the film leader is not wound around the take-up spool 9 during film loading, the take-up spool 9 continuously rotates at the initial take-up speed Vs as shown by the solid line in FIG. On the other hand, the sprocket 22 is sped up by the combination of gears 18 and 19, and rotates intermittently by the combination of notched gear 20 and gear 21. This sprocket 2
2 has eight protrusions 22a on the outer periphery, and these protrusions 22a engage with the perforation of the film to temporarily reduce the initial winding speed Vs of the take-up spool 9.
The film is intermittently transferred two perforations at a speed faster than the perforation. When this film leader section is intermittently fed so as to come into contact with the outer periphery of the take-up spool 9, the perforation is caused by the claw 9a.
The film leader portion is wound around the outer periphery of the take-up spool 9.

After loading the film, when a release button (not shown) is pressed to take a picture, the motor 1 rotates as shown in FIG. 3 and advances the film by two perforations at high speed. Since the take-up spool 9 is continuously rotating at almost the same speed as the initial take-up speed Vs, it takes up the film fed by the sprocket 22, but the sprocket 2
Since the feed speed of 2 is fast, slack in the film is formed between the sprocket 22 and the take-up spool 9. Since the take-up spool 9 is continuously rotating, this slack in the film is absorbed after a short period of time. Note that the intermittent feeding of the film by the sprocket 22 is not necessarily performed when the motor 1 is started, but is performed while the motor 11 is rotating, and the winding speed of the take-up spool 9 depends on the winding diameter. Therefore, the position at which intermittent feeding is performed shifts accordingly.

After the sprocket 22 has sent two perforations, the sprocket 22 is connected to the gear 21 and the notched gear 20.
The mesh is disengaged and it becomes free. The film is therefore drawn directly from the cartridge by the take-up spool 9 and wound onto the take-up spool 9. Note that since the winding spool 9 becomes thicker, the winding speed increases from the initial winding speed Vs toward the final winding speed V _E. In this embodiment, the final winding speed V _E is set to be the same as the film feed speed during intermittent rotation of the sprocket 22, so as the number of photographed frames increases, the amount of slack in the film during winding decreases, and the final number of frames increases. For example, at the 36th frame, no film slack occurs during winding.

While the film is being pulled out from the cartridge by the rotational force of the take-up spool 9, the sprocket 22 is continuously rotated by the film. The rotation of the sprocket 22 is controlled by the shutter set cam 24 by gears 21 and 22 having the same number of teeth.
and the control cam 25. The shutter set cam 24 has a leaf shape, and during one rotation, a lever (not shown) in contact with the shutter set cam 24 is pushed to set the shutter (not shown). On the other hand, control cam 2
5 is for detecting that the sprocket 22 rotates once and feeds the film by one frame;
A cam follower (not shown) is attached to the notch 25a.
When this happens, a switch (not shown) linked to this turns off. When this switch is turned off,
At the same time as the power supply to the motor 1 is stopped, a short circuit is formed and the motor 1 suddenly stops. When the release button is pressed, the shutter is operated, and after this operation, the switch is turned on to energize the motor 1 again, and the spool is wound up by one frame as described above.

When winding of the film is completed, the motor 1 automatically starts reverse rotation in the direction shown by the dotted line in response to a signal from a known film end detection device such as a film tension increase detection device. When the rotation of the motor 1 is transmitted to the gear 7, the gear 7 makes a planetary motion around the gear 5. As a result, the connecting arm 6 pivots to the right, the gear 7 meshes with the gear 10, and the rotation of the motor 1 is transmitted to the rewinding fork 11. During this rewinding, the sprocket 22 is intermittently rotated at a high speed in the direction shown by the dotted line, and 1/4 frame of film is rewound and transferred from the now free take-up spool 9. The rewinding fork 11 continuously rotates the shaft in the cartridge connected to it at a slower speed than the sprocket 22, and rotates the film so as to absorb the slack in the film formed between the sprocket 22 and the shaft in the cartridge. Rewind. When the notched gear 20 and the gear 21 are disengaged, the sprocket 22 becomes free.
A shaft in the cartridge connected to the rewind fork 11 draws the film directly from the take-up spool 9. Thereafter, when the notched gear 20 meshes with the gear 21, the sprocket 22 rotates again at high speed and sends 1/4 frame of film to the cartridge. In this way, the film is pulled out from the take-up spool 9 and rewound onto the cartridge.

In the above embodiment, the motor 1 and the take-up spool 9 are separated, but the motor 1 may be housed in the take-up spool 9, and the sprocket has a plurality of protrusions and a pair of sprockets. A film transport belt hung on a pulley can be used.

As described above, according to the present invention, the sprocket is rotated intermittently at high speed, and the sprocket is disconnected from the motor while the sprocket is stopped, so a friction clutch is provided on the take-up spool. , or without installing a one-way clutch in the sprocket drive system.
It is possible to eliminate the need for the film to be forcibly pulled between the sprocket and the take-up spool.
Therefore, compared to conventional autoloading cameras, the structure is simpler and the cost can be lowered. Furthermore, since the sprocket rotates intermittently, the film leader transferred into the take-up chamber by the sprocket during film loading is stopped for a period of time, so that the perforation of the film and the take-up spool pawl are in contact with each other. Engage quickly and reliably. It is particularly effective to apply the present invention to a type in which a hole is provided at the tip of the film leader section and a projection is provided on the take-up spool to engage with the hole.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing one embodiment of the present invention;
This figure is an explanatory view showing the rotation of the sprocket and take-up spool during film loading, and FIG. 3 is an explanatory view showing the feeding state of valid frames after film loading. 1... Motor, 6... Connection arm, 9... Winding spool, 11... Rewinding fork, 21...
Notched gear, 22... sprocket, 25... control cam.

Claims (1)

[Claims for Utility Model Registration] (1) A film feeder for a camera that is equipped with a sprocket that engages with the perforation of the film and a take-up spool that continuously winds the film, and that is driven by a motor. The feeding device includes an intermittent rotation mechanism for intermittently rotating a sprocket so as to transfer the film by a length less than one frame of the film, and a winding mechanism for creating slack in the film between the sprocket and the take-up spool. A film feeding device for a camera, comprising a speed increasing mechanism for rotating a sprocket at a speed faster than the winding speed of a spool. (2) The film feeding device for a camera according to claim 1, wherein the intermittent rotation mechanism includes a notched gear.