JPH04314043A - Film feeding amount detecting device for camera - Google Patents

Abstract

PURPOSE:To smoothly move a film to the film taking-up spool side of a camera without making the leading edge of the film bend at a position of a roller member while accomplishing to make the diameter of a sprocket small and to make the camera compact. CONSTITUTION:Position setting means 14, and 15b setting to a condition in which the sprocket 7 has already positioned in a specified rotating range when the leading edge of the film is fed to the position of the roller member 3 are provided, so that the leading edge of the film and the tip part of the tooth part of the sprocket are not engatged each other by setting the sprocket on the conditio in which the sprocket is positioned in a specified rotating range before the leading ege of the film is fed to the position of the roller member.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a film advance detection device for a camera using a film having a large pitch of perforations (at least one per screen).

0002

2. Description of the Related Art In conventional cameras, there are the following film feed amount detection means for feeding film by a fixed length.

1) A sprocket with teeth that mesh with the perforations of the film is used, and the amount of rotation of the sprocket as the film is fed is detected by a pulse plate, etc. 2) A roller pressed against the film 3) A device in which the amount of rotation of the roller member accompanying film feeding is detected by a pulse plate, etc. 3) A device in which the perforation of the film is detected by a photoreflector, etc.
However, in 1) to 3) above,
It had the following drawbacks.

First, 1) will be explained using FIG. 14. In FIG. 14, the pitch of the perforation P (this corresponds to the pitch of one frame of film) is L, the radius of the bottom circle of the sprocket 101 excluding the tooth 101a is B, and the tooth of the tooth 101a is If the length is A, the outer diameter of the sprocket 101 is "A+B", but "A+B"
must satisfy at least the relationship (A+B)2≧B2+(L/2)2. From this,
The outer diameter of the sprocket 101 is "L/2" or more. Therefore, if a film with a large pitch L of perforations P is used, the sprocket 101 will become large.

[0005] In 2), errors occur due to slippage between the roller and the film, and as a result, they accumulate, resulting in large errors.

[0006] In the above-mentioned method 3, the cost of the camera increases because it is necessary to include a photodetector element such as a photoreflector and its driving circuit. Moreover, the camera control circuit for controlling them becomes expensive and complicated. Furthermore, since the film feed amount cannot be output mechanically,
It is not possible to use a mechanical counter to measure the number of film frames, but a counter using a liquid crystal display or the like must be used, which also increases the cost of the camera.

[0007] Therefore, the applicant of the present application has proposed a method that can eliminate each of the above-mentioned drawbacks: ``A roller member that is pressed against the film surface and rotates by receiving a driving force as the film is fed by frictional force. , which rotates integrally with the roller member, and whose teeth engage with the perforations of the film when feeding one frame of the film, and which rotate while engaging with the perforations of the film. and a sprocket having a shape that has a second rotation range that rotates with the teeth not engaging the perforations,'' was filed on the same day. .

[0008]

[Problems to be Solved by the Invention] By providing a device configured as described above, it is possible to prevent errors in film feed amount and complicated circuit configurations, and to prevent Since the diameter of the camera can be made small, the camera can be made compact, and it can be said to be a very effective device. However, in the above structure, the film cartridge proposed in U.S. Pat. No. 4,834,306 (i.e., the film cartridge)
ejecting the film from the film cartridge in the cartridge chamber using a device that allows the film to be ejected and fed from the cartridge by rotating a supply spool in the cartridge; Feeding type cameras (for example, Japanese Patent Application Laid-Open No. 2-67535, Japanese Patent Application No. 2-20057)
3, etc.), or when used in a camera etc. that uses a roller with driving force to feed the film to the film take-up spool of the camera, the leading edge of the film 101 When the portion 101a (see FIG. 15) advances, the teeth 102 of the sprocket 102 touch the film 101.
If the roller 103 is outside the traveling trajectory of the film 101, the roller 103 smoothly enters between the roller 103 and a pressing roller (not shown) that presses the roller 103 against the surface of the film 101. The tip of the portion 102a is attached to the film 101 as shown in FIG.
When the sprocket 101 is located within the running trajectory of the sprocket 10, the film tip 101a
When the film 101 comes into contact with the teeth 102a of the sprocket 102, the frictional force generated on the contact surface and the film 101
Depending on the relationship such as the direction of the force pushing 02a, sprocket 1
It is conceivable that the film 101 cannot be rotated and the film 101 is prevented from advancing, resulting in buckling of the film 101.

[0009] An object of the present invention is to reduce the diameter of the sprocket, thereby making the camera more compact.
It is an object of the present invention to provide a film feed amount detection device for a camera that can smoothly advance the leading end of the film toward the film take-up spool side of the camera.

0010

[Means for Solving the Problem] In the present invention, the sprocket is already set in a predetermined rotation range at the time when the leading end of the film is fed to the position of the roller member. A position setting means is provided.

[0011]

[Operation] The position setting means sets the sprocket in a predetermined rotation range before the leading end of the film is fed to the position of the roller member, and sets the sprocket to a position between the leading end of the film and the sprocket. It is made so that it does not engage with the tip of the tooth. In other words, the sprocket is set at a rotational position such that the tips of its teeth are outside the film travel trajectory.

0012

[Embodiment] Fig. 1 and Fig. 2 show a first embodiment of the present invention. Fig. 1 is a perspective view showing the configuration of the main parts according to the invention, and Fig. 2 is a plan view showing the structure of the main parts. It is.

In these figures, 1 is a film cartridge, and 2 is a film having perforations 2a and 2b. In this embodiment, it is assumed that there is only one perforation per frame of film. That is, if the aperture size is ``36 mm'', the pitch of one frame is ``38 mm'' so that the screens do not overlap. Therefore, the pitch L between perforations 2a and 2b
It is also "38mm".

3 is a roller rotatably disposed on the camera body (not shown) so as to receive rotational force as the film 2 travels; 4 is a position opposing the roller 3 with the film 2 sandwiched therebetween; A pressing roller is rotatably attached to a portion 5a of a pressing lever 5, which will be described later, 5 is a pressing lever rotatably attached to a camera body (not shown) at a portion 5b, and 6 is a pressing lever with one end attached. The lever 5 is fixed to the camera body (not shown) and presses the other end.
This spring is attached to the arm 5c of the lever 5 and urges the pressing lever 5 in the counterclockwise rotation direction to press the pressing roller 4 against the roller 3.

7 is a sprocket, and a shaft 8 connects the roller 3.
It is fixed to the shaft 8 so as to rotate integrally with the shaft 8. 9
is a disk, and is fixed to the shaft 10 so as to rotate integrally with the roller 3 and sprocket 7. 1
Reference numeral 1 denotes a pulse base having a conductive part 11a and a non-conductive part 11b, which is fixed to the disk 9. Reference numerals 12 and 13 are pulse contacts that generate pulse signals as the pulse base 11 rotates.The pulse signals generated here are output to a control circuit (not shown) that controls various operations of the camera, and It is processed as a signal for detecting the amount. 14 is a sprocket position setting pin provided on the sprocket 7.

Reference numeral 15 denotes a cover of the cartridge chamber 16, that is, a back cover, which is rotatably attached to the camera body (not shown) at a portion 15a.As shown in FIG. The cartridge chamber 16 is opened and the film cartridge 1
can be loaded. 17 is the back cover release lever, and the elongated hole 17
a and 17b are dowels 18 and 19 from the camera body (not shown)
is slidably fitted to the A spring 20 has one end fixed to the camera body (not shown) and the other end fixed to the back cover release lever 17, and urges the back cover release lever 17 in the direction of arrow A (see FIG. 2). 21 is a known means (for example, Japanese Patent Application No. 1999-1-
344801), which is attached to a film rail surface (not shown) while maintaining a predetermined gap.

The film cartridge 1 used in this embodiment is of the type proposed in the above-mentioned US Pat. No. 4,834,306, in which the film 2 is can be ejected and fed from within the cartridge 1.

In the above structure, the film cartridge 1 is loaded into the cartridge chamber 16 from the state shown in FIG. 2 in which the back cover 15 is open, and the back cover 15 is closed. 15 has a tapered portion 15c that contacts the claw portion 17c of the back cover release lever 17, and resists the biasing force of the spring 20 and uses the tapered portion 15c to open the back cover release lever 17.
After moving in the direction opposite to the arrow A and climbing over, the locking portion 15d is locked by the claw portion 17c, and the state shown in FIG. 3 is maintained.

In the process of closing the back cover 15,
The sprocket position setting pin 14 is attached to the arm portion 15 of the back cover 15.
b, if the sprocket 7 and the sprocket position setting pin 14 are in the rotational position as shown in FIG. As the sprocket position setting pin 14 is being closed, the sprocket position setting pin 14 is pushed out of the movement locus of the arm portion 15b. As a result, the sprocket 7 rotates, and the teeth 7a of the sprocket 7 move out of the film travel path as shown in FIG. In addition, the arm portion 1 of the back cover 15
5b is out of the locus of rotation of the sprocket position setting pin 14 about the rotation axis 7b of the sprocket 7.

[0020] After that, the film 2
The film car is transported by a known film feeding gear train such as No.
It is pushed out from inside the cartridge 1 and fed (see Figure 4)
. At this time, since the teeth 7a of the sprocket 7 are out of the running trajectory of the film 2 as described above, the leading edge of the film does not come into contact with the leading edge of the teeth 7a of the sprocket 7. Therefore, the leading end of the film is prevented from coming into contact with the leading end of the tooth portion 7a of the sprocket 7, preventing the film from advancing and buckling.

As the film 2 is further fed from this state, it enters between the roller 3 and the pressing roller 4. As the film 2 is fed, the roller 3 rotates clockwise due to the frictional force generated by the biasing force of the spring 6. Further, the sprocket 7, which is configured to rotate integrally with the roller 3, also rotates clockwise accordingly. The teeth 7a of the sprocket 7 come into contact with the surface of the film 2, preventing further rotation, but since the film 2 slips on the surface of the roller 3, the film 2
is being shipped. This state is shown in FIG.

As the film 2 is further fed, the part
Since the foration 2a is in a position where it can engage with the tooth 7a, the tooth 7a and the perforation 2a are connected as shown in FIG.
engages with.

[0023] After that, the perforation 2a and the tooth part 7
Since the sprocket 7 is engaged with the sprocket 7 as shown in FIG. 7 as the film 2 is fed.

The sprocket 7 is rotated until the perforation 2a and the tooth 7a are disengaged from each other as shown in FIG.
and film 2 are positioned and rotated,
After the engagement is released, the roller 3 rotates again due to the frictional force generated by the biasing force of the spring 6.

[0025] Here, if the diameter of the roller 3 is D and the pitch of the perforations 2a and 2b is L (see Fig. 5), then the relationship is ``D x π <L''. , next par
Before the foration 2b reaches a position where it can engage with the tooth 7a, the sprocket 7 is rotated by the frictional force of the spring 12 until the tooth 7a comes into contact with the surface of the film 2. This state is shown in FIG.

Even if the film 2 is fed until the next perforation 2b arrives, the roller 3 simply slips on the surface of the film 2, and the roller 3 and sprocket 7 do not rotate.

8 to 9, even if the roller 3 has some slippage on the surface of the film 2 and the amount of feed of the film 2 and the amount of rotation of the roller 3 do not exactly match. , if the diameter D of the roller 3 is set sufficiently smaller than "L/π", the tooth 7 will be removed before the next perforation 2b comes.
A will come into contact with the second side of the film. Then, the next perforation 2b engages with the tooth portion 7a, and the sprocket 7 and the perforation 2b of the film 2 are positioned again, so that rotational errors of the sprocket 7 are not accumulated.

Thereafter, when normal photographing is performed and all frames of the film 2 have been photographed, the film 2 is rewound into the film cartridge 1, and when this rewinding operation is completed, the back cover 15 is opened again. is opened and the film cartridge 1 is taken out from inside the cartridge chamber 16.
When the back cover release lever 17 is manually moved in the direction opposite to the arrow A against the biasing force of the spring 20, the engagement between the claw portion 17c and the locking portion 15d is released, and as shown in FIG.
The back cover 15 is opened as shown in FIG.

In this process, the arm portion 15b of the back cover 15 may engage with the sprocket position setting pin 14 depending on the rotational position of the sprocket 7, push it outside,
By rotating the sprocket 7, the engagement between the arm portion 15b and the sprocket position setting pin 14 is released, and as shown in FIG.
The back cover 15 opens as shown in FIG.

When the sprocket 7 is rotated clockwise from the position shown in FIG. 3 to the position shown in FIG. 10 due to opening and closing of the back cover 15 (this is referred to as the third rotation range),
The arm portion 15b and the sprocket position setting pin 14 do not come into contact with each other, and the tooth portion 7a of the sprocket 7 is outside the travel trajectory of the film 2.

Further, when the sprocket 7 is at a rotational position outside the third rotational range, the sprocket 7 is placed in either the position shown in FIG. 3 or the position shown in FIG. 10 by the opening/closing operation of the back cover 15. In both of these states, the teeth 7a of the sprocket 7 are outside the travel trajectory of the film 2, so after opening and closing the back cover,
Even when the film 2 is fed, the leading edge of the film never comes into contact with the teeth 7a of the sprocket.

[0032] Furthermore, within the scope of the claims of the present invention,
The period from the rotational position shown in FIG. 6 through FIG. 7 to the rotational position shown in FIG. 8 is called the first rotational range, and the other rotational range is called the second rotational range.
(including the above-mentioned third rotation range).

11 and 12 show a second embodiment of the present invention, FIG. 11 is a plan view showing the positional relationship of each member before loading the film cartridge, and FIG. 12 is a plan view showing the positional relationship of each member before loading the film cartridge. FIG. 3 is a plan view showing the positional relationship of each member when loaded. Parts similar to those in the first embodiment and parts having the same functions are given the same reference numerals.

In these figures, 22 is a card rotatably attached to the camera body (not shown) at a portion 22c.
The arm portion 22a of the cartridge detection lever can protrude into or retreat into the cartridge chamber 16. A spring 23 has one end attached to the camera body and the other end attached to the cartridge detection lever 22, and applies a biasing force for counterclockwise rotation to the cartridge detection lever 22. Reference numeral 24 denotes a stopper provided on the camera body (not shown), which restricts the position of the cartridge detection lever 22 in the counterclockwise rotation direction.

Reference numeral 25 denotes an interlocking lever rotatably attached to the camera body (not shown) at a portion 25c.
5a is in an engageable relationship with the arm portion 22b of the cartridge detection lever 22. 26 is attached at one end to the camera body (not shown) and at the other end to the interlocking lever 25.
5 is a spring that applies a biasing force in the clockwise rotation direction. 27 is a stopper provided on the camera body (not shown);
The position of the interlocking lever 25 in the clockwise rotation direction is regulated.

The arm portion 25b of the interlocking lever 25 described above can be engaged with the sprocket position setting pin 14 depending on the rotational position of the sprocket 7, similar to the arm portion 15b of the back cover 15 in the first embodiment. . Figure 11 shows the cartridge chamber 1.
When the film cartridge 1 is loaded from this state, the cartridge detection lever 22 rotates clockwise against the urging force of the spring 23. , the arm portion 22b is the interlocking lever 2
5 and rotates the interlocking lever 25 counterclockwise against the biasing force of the spring 26 to bring it into the state shown in FIG.

When the interlocking lever 25 rotates to the left as described above, if the sprocket position setting pin 14 is located within this movement locus, the arm portion 25b moves toward the sprocket position setting pin 14. Push away and sprocket 7
is rotated to push the sprocket position setting pin 14 together with the sprocket 7 out of the movement trajectory of the arm portion 25b. At this time, the teeth 7a of the sprocket 7 are located outside the running trajectory of the film 2, as in the first embodiment.

FIG. 13 is a plan view showing the main structure of the third embodiment of the present invention, and parts similar to those of the first and second embodiments and parts having the same functions are given the same symbols. There is.

In this embodiment, the sprocket 7 is positioned within a predetermined rotation range in conjunction with the operation of the back cover release lever 17.

The back cover release lever 17 has an arm portion 17d, and the back cover release lever 17 moves in the direction of arrow A for opening and closing the back cover 15.
When the sprocket position setting pin 14 is located within the movement locus of the arm 17d when the arm 17d is moved in the direction or the opposite direction, the arm 17d comes into contact with the sprocket position setting pin 14, and the sprocket 7 to rotate the sprocket position setting pin 14 together with the sprocket 7 out of the movement locus of the arm portion 17d. At this time, the teeth 7a of the sprocket 7 are connected to the film 2 as in the first and second embodiments.
The vehicle will be located outside the travel trajectory of the vehicle. In this embodiment, the relative position between the sprocket position setting pin 14 and the tooth portion 7a of the sprocket 7 is different from that in the first and second embodiments.

According to each of the above embodiments, the sprocket 7 is moved by the operation related to loading and unloading the film cartridge 1.
Since the tip of the tooth 7a of the sprocket 7 is configured to escape outside the film running trajectory, the tip of the film 2 comes into contact with the tip of the tooth 7a of the sprocket 7 during film feeding, and its progress (roller 3 It is possible to prevent the film 2 from buckling due to being obstructed (between the film 2 and the pressing lever 4).

[0042]

[Effects of the Invention] As explained above, according to the present invention,
At the time when the leading edge of the film is fed to the position of the roller member, a position setting means is provided which positions the sprocket in a predetermined rotation range, so that the leading edge of the film is fed to the position of the roller member. - Before the film is fed to the position of the film member, the sprocket is set in a predetermined rotation range so that the leading end of the film does not engage with the leading end of the teeth of the sprocket. . Therefore, although the purpose of the device that the applicant filed on the same day, which is to reduce the diameter of the sprocket and make the camera more compact, is achieved, the leading edge of the film buckles at the position of the roller member. This makes it possible to smoothly advance the film toward the film take-up spool of the camera.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of main parts in a first embodiment of the present invention.

FIG. 2 is a plan view showing the configuration of main parts in the first embodiment of the present invention.

3 is a plan view showing the state of each member when a film cartridge is loaded from the state of FIG. 2; FIG.

4 is a plan view showing a state in which the film has been extruded from the inside of the film cartridge from the state shown in FIG. 3; FIG.

5 is a plan view showing a state in which the film has passed the position of the rollers as the film feeding progresses further from the state shown in FIG. 4; FIG.

6 is a plan view showing a point in time when the film feed further advances from the state shown in FIG. 5 and the teeth of the sprocket engage with the perforations of the film; FIG.

7 is a plan view showing a state in which film feeding has further progressed from the state shown in FIG. 6 while the tooth portion remains engaged with the perforation; FIG.

8 is a plan view showing a state in which the film feed further advances from the state shown in FIG. 7 and the tooth portion comes out of the perforation; FIG.

9 is a plan view showing a state before the film feeding progresses further from the state shown in FIG. 8 and the teeth mesh with the next perforation; FIG.

FIG. 10 is a plan view showing the state of each member when the film cartridge is taken out from the cartridge chamber after all frames have been photographed.

FIG. 11 shows a film car in a second embodiment of the present invention.
FIG. 7 is a plan view showing the state of each member when the cartridge is not loaded.

FIG. 12 shows a film car in a second embodiment of the invention.
FIG. 3 is a plan view showing the state of each member when the cartridge is loaded.

FIG. 13 is a plan view showing the configuration of main parts in a third embodiment of the present invention.

FIG. 14 is a diagram showing the relationship between a conventional sprocket and perforations provided in a film.

FIG. 15 is a plan view illustrating a problem in the device that was filed on the same day by the applicant of the present application.

[Explanation of code] 2 Film 3
Roller 4 Pressing roller 7 Sprocket 7a Teeth 9 Disc 11 Pulse base 12, 13 Pulse contact piece 14 Sprocket position setting pin 15
Back cover 15b Arm part 17 Back cover opening lever 17d Arm part 22 Cartridge detection lever 25 Interlocking lever

Claims (4)

[Claims] Claim 1: A roller member that is pressed against the film surface and rotates by receiving a driving force as the film is fed by frictional force, and a roller member that rotates integrally with the roller member and feeds one frame of the film. , a first rotation range in which the teeth engage and rotate with the perforations of the film;
A camera comprising: a sprocket having a second rotation range that rotates when not engaged with the sprocket; and signal generating means for generating a signal corresponding to the rotation speed of the sprocket as a film feed amount. In this film feed rate detection device, the sprocket is already set in a predetermined rotation range at the time when the leading end of the film is fed to the position of the roller member. A film feed amount detection device for a camera, characterized in that it is provided with a position setting means. 2. The film feed amount detection device for a camera according to claim 1, wherein the position setting means operates in conjunction with opening and closing operations of the camera back. 3. The position setting means operates in conjunction with loading or unloading of the film cartridge into or from the cartridge chamber of the camera.
Film advance detection device for the camera described. 4. The predetermined rotation range in which the position setting means is located is a third rotation range within the second rotation range in which the tips of the teeth of the sprocket are outside the film running trajectory. A film feed amount detection device for a camera according to claim 1, 2 or 3.