JPH066332Y2 - Film holding device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention measures the film feed amount by a photoelectric detector or the like.
The present invention relates to a film pressing device in a camera having a control mechanism.

[Conventional technology]

In a motor-driven compact camera loaded with a 35 mm film, the number of passing film perforations is counted by a photo sensor instead of the one-frame feed control by the drive sprocket, and the film count of the film is calculated based on this count value. A camera is known which is configured to perform single-frame feed control. In such a camera, the film is fed by driving the take-up spool, and the rotation of the motor driving the take-up spool is stopped by the count signal from the photosensor. Further, in the pre-winding type camera, the loaded film is preliminarily wound on a take-up spool, and every time one frame is photographed, the patrone shaft is driven to rewind the film one frame at a time.

[Problems to be solved by the device]

However, as described above, in the case of a camera that performs one-frame feed control of a film without using a drive sprocket, a mechanical interlocking mechanism from the motor to the drive sprocket can be omitted, but there is a drawback that the frame intervals tend to be uneven. .

This is because in a camera that uses a drive sprocket, the drive sprocket is always engaged with the perforations, so precise control of the drive of the drive sprocket enables one-frame advance of the film. With cameras that do not have one, there is nothing that mechanically blocks the movement of the film after it has advanced one frame, so when the film feed motor is stopped, only the film is slightly fed, and This is because when the camera is vibrated, the film loosens in the cartridge or from the take-up spool of the camera, causing the film to move slightly behind the aperture.

To prevent this, the film should be loaded so that it does not move easily.However, if such a structure is simply adopted, when the film is continuously fed, that is, when the film is fed normally, When the film is rewound by the camera, or when the pre-winding camera is used for the pre-winding, the film feeding load becomes large, which is disadvantageous in terms of power consumption.

[Purpose of device]

The present invention has been made in view of the above-mentioned drawbacks. Even when the film is fed without using the drive sprocket, the frame interval is properly maintained, and the feeding load does not increase when the film is continuously fed. It is an object of the present invention to provide a film pressing device as described above.

[Means for Solving the Problems]

In order to achieve the above object, the present invention is configured to press the back surface of the film against the film receiving surface outside the effective exposure range by a film pressing portion, apart from the pressure plate that presses the film from the back surface to the film receiving surface where the aperture is formed. There is. Moreover, the film pressing spring for urging the film pressing portion in the above direction is formed into a plate shape along the film feeding direction, and the leading end portion urging the film pressing portion in the above direction is continuously fed. I tried to turn from the upstream side to the downstream side.

[Action]

The direction in which the film is fed by one frame and the direction in which the film is continuously fed are always opposite to each other. Therefore, by devising the shape of the film pressing spring that urges the film pressing portion as described above, it is possible to make the urging force of the film pressing spring strong or weak according to the feeding direction of the film. Therefore, it is possible to prevent the frame intervals from becoming irregular without increasing the load during continuous film feeding.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

〔Example〕

FIG. 1 shows a state of the back cover of a camera using the present invention when viewed from the inner surface side, and FIG. 2 shows a cross section of a main part of the camera using the present invention along the film feeding direction. . In FIGS. 1 and 2, an aperture for defining an exposure area for one frame of film is formed on the film receiving surface 2 formed on the camera body 1, and as a result, as shown in FIG.
As shown in, the effective exposure range 4 is defined on the film 3, and the photographing is performed in this range.

Known film rails and pressure plate rails are formed on the film receiving surface 2. The pressure plate 5 is attached to the back cover 7 via a pressure plate spring 6, and the front surface of the pressure plate 5 contacts the pressure plate rail. Then, the film 3 is passed through a gap (tunnel interval) formed between the film rail and the front surface of the pressure plate 5. The feeding direction of the film 3 is the left-right direction in FIGS. 1 and 2. Note that this camera is a pre-winding type camera that does not use a drive sprocket for feeding the film, and immediately after loading the film, the film 3 is continuously fed in the right direction in FIG. 2 (the left direction in FIG. 1), The entire length of the film 6 is wound on the winding spool of the camera. Then, each time a picture is taken, the motor drives a patrone shaft that is rotatably incorporated in the patrone, and the film 3 that has been taken is wound into the patrone frame by frame.

The back cover 7 is provided with bosses 7a at two positions, and the above-mentioned pressure plate springs 6 are fitted into the bosses 7a. The pressure plate 5 is provided with openings 5a and 5b having concave portions. The bosses 7a are loosely inserted into the openings 5a and 5b, and the retaining screws 9 and 9 are screwed to the ends of the respective bosses 7a. It is worn.

A plate-shaped film pressing spring 1 integrated with the pressure plate spring 6
0 is integrally formed along the feeding direction of the film 3. The film pressing spring 10 has its tip portion extending from the upstream side to the downstream side, that is, in the preliminary winding direction when the film 3 is continuously fed, and the roller 12 is axially attached to the tip portion by a shaft 11. Has been done. Since the pressure plate spring 6 has an urging force in the direction of pressing the back end of the film 3 with its tip portion, the roller 12 projects toward the film 3 side through the opening 5c of the pressure plate 5.

As shown in FIG. 2, the receiving surface 2 is provided with a recess 13 corresponding to the roller 12. Therefore, the film 3 is sandwiched between the roller 12 and the recess 13. As a result, as shown in the drawing, the film 3 is slightly deformed so as to enter the recess 13. And
When the film 3 is fed in the winding direction (the one-frame feeding direction after shooting), a pressing force in the feeding direction of the film 3 is applied to the tip end portion of the film pressing spring 10. This pressing force causes the tip of the film pressing spring 10 to have a recessed portion 1.
The film pressing spring 10 effectively presses the back surface of the film 3 via the roller 12 because it acts in such a manner as to bite into the film 3, and applies an appropriate load to the film 3.

On the other hand, when the film 3 is fed in the direction in which the front end of the film pressing spring 10 is oriented, that is, in the preliminary winding direction, the pressing force from the back surface of the film received by the front end of the film pressing spring 10 is the front end of the film pressing spring 10. It acts in the direction in which the part is lifted from the recess 13. Therefore, the load applied to the back surface of the film 3 during the preliminary winding is smaller than that during the winding.

A contact piece 15 is arranged behind the roller 12, and the contact piece 15 is held by a support member 16 fixed to the wall surface of the back cover 7 and made of non-conductive plastic or the like.
Further, a lead wire 17 is connected to the contact piece 15 via a support member 16, and is connected to a circuit for detecting the presence or absence of a film together with the lead wire 18 connected to the pressure plate spring 6. That is, the tip of the film pressing spring 10 and the contact piece 15 are normally separated from each other with a certain distance maintained, but when the film 3 is loaded, the roller 12 is pushed down and comes into contact with each other. Circuit 3 shorted and film 3
The existence of is confirmed.

The operation of the above embodiment will be described. When the camera body 1 is loaded with the film 3 and the back cover 7 is closed, the film 3 is sandwiched in the tunnel space formed by the pressure plate 5 urged by the pressure plate spring 6 and the film receiving surface 2. At this time, the roller 12 urged by the film pressing spring 6 moves to the film 3
The outside of the effective exposure range 4 of the film from the back cover 7 to the film receiving surface 2
Press in the direction toward. Also, due to this reaction,
The tip of the film pressing spring 10 behind the contact piece 15 and the roller 12 which have been separated comes into contact with the contact piece 15 and the film 3
Is confirmed, and preliminary winding is started.

As described above, the plate-shaped film pressing spring 10 is formed along the feeding direction of the film 3, and further, since the tip end portion is extended in the preliminary winding direction in which the film is continuously fed, the continuous feeding is performed. The pressing force received from the backside of the film 3 reduces the urging force of the film pressing spring 10,
The feeding load of the film 3 is reduced.

When the preliminary winding is completed, the shutter is charged and the preparation for photographing is completed. When you release the shutter and shoot,
A feeding motor (not shown) in the camera body 1 is driven, and a cartridge shaft built in the cartridge rotates in the film winding direction. As a result, one frame of film advance is started. Then, a stop signal is generated by a photo sensor (not shown) when the number of passing perforations 3a reaches an appropriate number, the driving of the feeding motor is stopped, and one frame feeding is completed.

By the way, at the moment when the feeding motor stops, inertia acts and, for example, the Patrone shaft slightly rotates in the same direction by an amount of backlash, and the film 3 often moves accordingly. However, since the roller 12 which is biased by the film pressing spring 10 comes into contact with the back surface of the film 3 and an appropriate load is applied thereto, the film 3 does not move due to the influence of the inertia described above. Even when the feeding of the film 3 is stopped, the load of the film 3 is applied by the pressing of the roller 12, so that the film 3 moves due to the influence of the vibration applied to the camera body 1 and the screen intervals become uneven. Nor.

FIG. 3 shows an embodiment in which the roller 12 used in the above embodiment is omitted, and the film 3 is pressed by the tip end portion of the film pressing spring itself. It should be noted that the same reference numerals are used for members that are common to the above-described embodiment.

In this embodiment, the tip portion of the film pressing spring 20 is bent as shown in the drawing, and the contact surface with the film back surface is rounded. The function of this contact surface is exactly the same as that of the roller 12 of the above-mentioned embodiment. Then, the most distal end portion bent to the side of the back cover 7 functions as a film detection switch for pairing with a contact piece 15 provided behind the back cover 7 to confirm the presence or absence of the film 3.

[Effect of device]

As described above, according to the film pressing device of the present invention,
Separately from the pressure plate, the film pressing part is pressed against the back surface of the film outside the effective exposure range, and the film pressing spring for urging the film pressing part is formed into a plate shape along the film feeding direction, and Since the leading edge of the pressing part is directed to the downstream side during continuous feeding of the film, it prevents the frame interval from becoming uneven by applying an appropriate load to the film when feeding one film. In addition, the load does not have to be increased during continuous film feeding, and the power source is not wasted.

Further, if the film pressing spring is formed integrally with the pressure plate spring, the number of parts can be reduced, the assembling man-hours can be rationalized, and the present invention can be implemented at low cost. Further, since the film pressing spring has different positions depending on the presence / absence of the film, it can be used also as a means for detecting the presence / absence of the film by turning on / off the switch.

[Brief description of drawings]

FIG. 1 is a schematic view of an inner surface side of a back cover of a camera using the present invention. FIG. 2 is a sectional view of an essential part of the back cover portion of the camera shown in FIG. FIG. 3 is a sectional view of an essential part of a back cover portion of a camera using another embodiment of the present invention. 2 ... Film receiving surface 3 ... Film 5 ... Pressure plate 6 ... Pressure plate spring 7 ... Back cover 10 ... Film pressing spring 12 ... Roller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigenori Goto 1-324 Uetake-cho, Omiya-shi, Saitama Fuji Photo Koki Co., Ltd. (56) Reference JP 59-218433 (JP, A) 50-89331 (JP, U)

Claims (5)

[Scope of utility model registration request] 1. A camera comprising a pressure plate for pressing a film from the back toward a film receiving surface on which an aperture is formed and which does not use a drive sprocket as a film feeding means, wherein the aperture is determined separately from the pressure plate. A film pressing portion that presses the back surface of the film toward the film receiving surface outside the effective exposure range, and a plate-shaped film pressing spring that biases the film pressing portion toward the back surface of the film, The film pressing spring is extended along the feeding direction of the film, and the tip end portion for urging the film pressing portion is directed from the upstream side to the downstream side when continuously feeding the film. Film holding device. 2. The film pressing device according to claim 1, wherein the film pressing spring is formed integrally with a pressure plate spring for urging the pressure plate. 3. The utility model registration claim according to claim 1, wherein the film pressing spring is deformed when the film pressing portion receives pressure from the film and switches a switch for detecting the presence or absence of the film. The film pressing device described. 4. The film pressing device according to claim 1, wherein the film pressing portion is a roller rotatably attached to a tip end portion of a film pressing spring. 5. The film according to claim 1, wherein the film pressing portion is a bent portion formed by rounding a tip contact portion of the film pressing spring into contact with the film. Holding device.