JPH0610934U - Camera sprocket - Google Patents

Abstract

(57) [Summary] [Objective] To provide a sprocket having a simple film feeding mechanism, a small number of parts, and a low cost. [Structure] The teeth 2 of a sprocket 1 connected to a shutter charge mechanism are made to have a normal tooth shape on the film winding side so as to be hooked on a perforation 6 and the rewinding side is loosened to allow the sprocket 1 to rewind the film. Was formed so that the perforations 6 of the film 5 could be rewound beyond the teeth of the sprocket 1 without rotating. As a result, it is possible to provide a film feeding mechanism having a small number of parts and a simple structure without providing the sprocket 1 with a complicated mechanism such as a one-way clutch.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sprocket for a camera.

[0002]

[Prior art]

 In some cameras, when the film is rolled up after shooting, the sprocket meshed with the film is rotated by the film feed, causing the shutter charge mechanism to charge up. In such a camera, when the film is completely rewound and the film is rewound, the shutter charge mechanism will rotate in the opposite direction to the operation if the sprocket and shutter charge mechanism remain connected. , A one-way clutch is provided between the sprocket and the shutter charge mechanism that connects rotation during normal winding and disconnects when rotated in the opposite direction, or disconnects with the shutter charge mechanism. A mechanism was installed to interlock with the sprocket by interlocking with push buttons when rewinding.

[0003]

[Problems to be solved by the device]

 However, providing the film feeding device with a complicated structure such as a one-way clutch or providing a mechanism for releasing the connection with the shutter charge mechanism increases the number of parts of the film feeding device and complicates the entire manufacturing process. Then, there was a problem that the cost of the camera was raised. Therefore, an object of the present invention is to provide a sprocket that has a simple structure and is connected to a shutter charge mechanism to be operated when the film is wound up, and on the other hand, is capable of smoothly feeding the film backward when rewinding the film. And

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the present invention, the tooth profile of the sprocket is made into a normal shape in which the tooth surface that hits when the film is wound is raised so that the perforation of the film is applied, while the tooth that hits when the film is rewound. The surface is formed with a gentle angle so that when the film is rewound, the perforations do not get over the teeth of the sprocket and are overcome and rewound.

[0005]

【Example】

 An embodiment of the sprocket according to the present invention will be described below.

FIG. 3 shows the camera 10 with the back cover 12 opened. The camera 10 is provided with a shutter button 13 on the right side of the upper surface, a film rewinding knob 14 on the left side, a viewfinder 15 substantially in the center on the front side, and a winding gear 16 on the right side. There is. The winding gear 16 is designed so that when one film 5 (illustrated in FIG. 1) is wound up, it is spun thereafter and the film is not wound further.

Inside the camera 10, a cartridge chamber 25 equipped with a film rewinding member 17 is provided from the left side, a lens section 18 is provided at the center, a sprocket 1 is provided at the right side thereof, and a take-up reel 19 is provided at the right end thereof. The back cover 12 is attached to the camera 10 by a hinge 20 so as to be openable and closable, and a holding member 22 for the film 5 is provided inside (on the front side in the drawing). The pressing member 22 is provided so that the distance between the holding member 22 and the back cover 12 can be elastically changed by the support legs 23, and a notch for not interfering with the sprocket 1 described later when the back cover 12 is closed at the upper left portion. 24 is provided.

The sprocket 1 is shown in FIG. As shown in FIG. 1, the sprocket 1 has teeth 2 at eight positions, and the central hole 3 is prevented from rotating on the rotary shaft (neither is shown) of the shutter charge mechanism provided inside. When the film 5 is wound up, it is rotated by the perforation 6 of the film 5 to charge the shutter charging mechanism. The tooth 2 of the sprocket 1 has a tooth profile 2a on the right side raised like the tooth profile of the conventional sprocket 30 shown in FIG. 4, while the tooth profile 2b on the left side is the tooth profile 2a on the right side. It is formed with a gentler slope. When the film 5 is loaded into the camera 10 and the sprocket 1 is engaged with the sprocket 1 of the film 5 and the film 5 is rewound while the film 5 is rewound, the tooth profile 2b on the left side is overcome without damage to the perforation 6 of the film 5. The slope is gentle enough to go. Such a sprocket 1 uses the tooth profile 2a on the feeding side of the film 5, that is, on the left side of the camera 10 in FIG. 3, and the tooth profile 2b on the winding side of the film 5 (on the right side in the figure). It is attached to 10.

Next, the operation of the sprocket 1 will be described. A film cartridge (not shown) is loaded into the cartridge chamber 25 of the camera 10, the perforation 6 is fitted to the claw 26 of the take-up reel 19 according to the sprocket 1, and the winding gear 16 is rotated to remove the slack of the film 5. And close the back cover 12. Then, the film 5 is pressed by the pressing member 22 to be accurately positioned behind the lens portion 18, and the teeth 2 of the sprocket 1 are projected from the notches 24 of the pressing member 22 to surely engage with the perforations 6 of the film 5. It When the film 5 is wound up, the perforation 6 comes into contact with the tooth profile 2a on the right side of the sprocket 1 to rotate the sprocket 1 and the shutter charging mechanism is charged. When the film 5 is wound up from the film cartridge to the final frame by performing sequential shooting, the rewinding knob 14 is rotated to rewind the film 5. Then, the perforation 6 of the film 5 gets over the tooth profile 2b on the left side of the sprocket 1 and is sequentially rewound into the cartridge.

Therefore, the sprocket 1 that is connected to the shutter charge mechanism to cause the shutter charge mechanism to perform a charging operation by winding up the film 5 and to smoothly perform the reverse feeding of the film 5 when the film 5 is rewound is provided with a unidirectional clutch. It can be provided with a simple configuration without providing a complicated mechanism such as a mechanism for releasing the connection with the shutter charge mechanism.

Further, in order to ensure the backward feeding of the film 5 at the time of rewinding, the position where the shutter charging mechanism stops after the charging operation is as shown in FIG. The perforation 6 of 5 may be set. By doing so, the height of the perforations 6 when going over the teeth 2 can be reduced, and the film 5 can be easily overcome.

FIG. 2 shows another embodiment of the sprocket. Like the sprocket 1 shown in FIG. 1, this sprocket 4 has a shape in which the tooth profile 2a on the right side of the tooth 2 is raised so that the perforation 6 is applied, and the tooth profile 2b on the left side is designed so that the perforation 6 can be overcome. It is formed with a gentle slope. A central shaft 7 fixed to the sprocket 4 is connected to a shutter charge mechanism (not shown), and is movably fitted into an elongated hole 8 provided in the camera 10. The long hole 8 is inclined so that the rewinding side of the film 5 becomes away from the film 5, and the inclination is such that the perforation 6 comes into contact with the tooth profile 2b of the sprocket 4 to press the sprocket 4. It is formed in the same direction as the direction of the force that sometimes occurs.

A spring 9 whose one end is locked to the camera 10 is attached to the central shaft 7, and by this panel 9, the central shaft 7 is one end of the elongated hole 8, that is, the end on the winding side of the film 5. It is pressed against the department. The spring force of this spring 9 is a force that can hold the central shaft 7 so that it does not move when the film 5 is being wound up, and when the film 5 is rewound, the sprocket 4 is long against the spring force. The force is set so that it moves in the opposite direction along the hole 8 and retracts.

Therefore, according to the sprocket 4, when the film 5 is being wound, the sprocket 4 is rotated by the perforation 6 while the film 5 is being wound, and the shutter charge mechanism is operated. On the other hand, when the film 5 is rewound, the sprocket 4 is moved to the other end of the slot 8 by being pressed by the perforation 6, so that the height of the tooth 2 is lowered, and the film is smaller than the sprocket 1 shown in FIG. The noise generated when the tooth 2 gets into the perforation 6 after the tooth 5 rides up the tooth 2 against the pressing force of the film pressing member 22 and the force applied to the film 5 can be reduced. .

In the above embodiment, the film 5 is wound up by the manual camera 10. However, in the present invention, the film winding is not limited to manual operation and may be automatic using a motor.

[0016]

[Effect of device]

 As described above, according to the sprocket of the present invention, the tooth profile on the surface in the film feeding direction is raised so as to be affected by the perforation of the film, while the tooth profile on the surface in the rewinding direction of the film is inclined without perforation. Since the shutter has been loosened, a one-way clutch or a mechanism for releasing the connection is not interposed between the shutter charge operation mechanism and the shutter is directly connected to perform the charge operation by feeding the film and the reverse operation of the film at the time of rewinding. It is possible to provide a sprocket that can be reliably fed with a simple configuration, the number of parts and the manufacturing process are reduced, and the cost is reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a sprocket according to the present invention.

FIG. 2 is a plan view showing a sprocket according to another embodiment of the present invention.

FIG. 3 is a rear view of the camera with the back cover opened.

FIG. 4 is a plan view showing a conventional sprocket.

[Explanation of symbols]

 1, 4 sprocket 2 teeth 2a, 2b tooth profile 5 film 6 perforation 10 camera 12 case back

Claims (1)

[Scope of utility model registration request] 1. A sprocket for a camera, which is rotated by the perforation of the film when the film is fed to perform a charging operation of a shutter charge mechanism, wherein the tooth surface of the sprocket is in contact with the perforation during film winding. Is a sprocket for a camera that has a rising slope shape so as to maintain the engagement with the perforation, and has a gentle slope shape so that the side abutting the perforation during film winding does not engage the perforation.