JPH08129226A - Film counter mechanism - Google Patents

Abstract

PURPOSE: To prevent an exposed frame number display board from being inadvertently turned even when a film counter mechanism is given strong shock or vibration, and to always realize a correct number of exposed frames. CONSTITUTION: A locking gear 45 is formed coaxially with the exposed frame number display board 35. A locking cam 41 is formed coaxially with a one-tooth gear 40. By allowing a part of the cam 41 to get into the teeth 45a of the gear 45, the turning of the display board 35 is prevented. A notch 41a is formed on the outer periphery of the cam 41 at a position where the gear 40 turns the display board 35. The tooth 45a of the gear 45 gets in the notch 41a, and the turning of the gear 45 is allowed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film counter mechanism that counts each time a photograph film is photographed in one frame.

[0002]

2. Description of the Related Art Conventionally, a film unit with a lens, for example, a photo film of 135 size is stored in advance in a unit body in which a photographing lens, a film winding mechanism, a shutter mechanism, and the like are incorporated in a unit body.
“I” (trade name) and the like are manufactured and sold by the applicant.
The lens-fitted film unit is inexpensive so that you can easily purchase it and take photos.

In such a film unit with a lens, a film counter mechanism is incorporated for displaying the remaining number of stored photographic films. This film counter mechanism is provided with a scale for the number of shots on the surface,
A disk-shaped number-of-photos display plate with teeth formed on the outer circumference, a driven sprocket that meshes with the perforation of the photo film and is rotated once every time the photo film is wound up one by one, and is provided coaxially with this driven sprocket. It is composed of a one-tooth gear which is a drive gear that is rotated integrally and meshes with the teeth of the number-of-photographs display plate to rotate by one graduation.

The one-tooth gear is formed by cutting out a part of the outer periphery of a cylinder having an elliptical cross section and providing teeth. When the teeth mesh with the number-of-photographs display plate, the number-of-photographs display plate corresponds to one scale. Rotate. The number-of-photographs display plate displays the number of frames that can be photographed at that time through a display window formed in the unit body. When the end display mark "E" on the number-of-shots display plate appears in the display window due to the winding operation after the last frame has been taken, the entire photo film will be stored in the film cartridge without the film winding mechanism being activated. It is completely stored.

Further, in Japanese Patent Laid-Open No. 5-19368,
A photographic film in which two perforations are formed per frame has been proposed. These two perforations are provided at the position corresponding to the beginning of each frame and the position corresponding to the trailing end of each frame, and it is premised that each frame is photographed between these perforations. Therefore, the perforations are alternately arranged at two types of intervals, a long interval for determining the length of one frame and a short interval for determining the mutual interval of each frame. Then, the driven sprocket meshed with this perforation is transferred by one frame of the photographic film.
It is designed to be rotated twice. The driven sprocket may be rotated 1/3 rotation or 2 rotations depending on the arrangement of the perforations of the photographic film.

[0006]

In order for the film counter mechanism described above to always display the correct number of shots, the one-tooth gear and the number-of-shots display plate must be reliably engaged. However, in the portion other than the teeth of the one-tooth gear and the teeth of the number-of-photographs display plate, there is a portion where the meshing amount decreases because the cross-sectional shape of the one-tooth gear is elliptical. Therefore, when a strong shock or vibration is applied to the lens-fitted film unit in a state where the amount of meshing is small, there is a problem that the number-of-photographs display plate unnecessarily rotates and the number of photos can not be accurately displayed. . Such a problem is caused by transferring one frame of the photographic film to 1/2 rotation or 1 /
The same applies to the film counter mechanism that rotates three times or two times.

The present invention has been made in view of the above problems, and even if the drive gear and the number-of-photographs display plate are meshed with each other, the number-of-photographs display plate is rotated by shock or vibration. The purpose is to prevent.

[0008]

In order to solve the above-mentioned problems, a film counter mechanism according to a first aspect of the present invention forms a locking gear coaxially and integrally with a photographing number display plate and coaxially with a drive gear. Part of one of the teeth of the locking gear enters the locking cam that integrally blocks the rotation of the shooting number display plate,
A notch is formed on the outer periphery of the locking cam when the drive gear rotates the number-of-photos display plate, and the teeth of the locking gear are inserted to allow rotation of the locking gear.

Further, in the film counter mechanism according to a second aspect of the present invention, the shaft end portion of the number-of-photographs display plate and the shaft end portion of the drive gear are formed so as to project, and these shaft end portions are formed by a shaft hole provided in the holding plate. It is held so that the axial distance between the axis of the number-of-photographs display plate and the axis of the drive gear is constant.

Further, in the film counter mechanism according to the third aspect of the present invention, the locking cam is composed of a cylindrical body, and each tooth of the locking gear is composed of an arc surface of the cylindrical body.

[0011]

When the photographic film is wound up by one frame, the driven sprocket rotates and the drive gear also rotates. When the drive gear rotates, there is a portion where the amount of meshing between the drive gear and the teeth of the shooting number display plate decreases, but there is a locking gear that is provided coaxially with the shooting number display plate and the same as the driving gear. Since it engages with the locking cam, the number-of-photos display plate does not rotate unnecessarily due to vibration or shock. Further, since the locking cam is composed of a cylindrical body and each tooth of the locking gear is composed of the circular arc surface of the cylindrical body, there is no hindrance to the rotation of the drive gear. Further, since the shaft end of the drive gear and the shaft end of the number-of-photographs display plate are held by the holding plate, the distance between the shafts is constant and the gears can be surely meshed. When the drive gear rotates the number-of-shots display plate, the notch formed on the outer periphery of the locking cam faces the teeth of the locking gear, and the engagement between the locking cam and the locking gear is released to display the number of captured images. The plate is rotated by one scale. After the rotation of one scale, the engagement cam and the engagement gear are engaged again, so that the photograph number display plate does not rotate unnecessarily due to a shock or the like.

[0012]

EXAMPLE FIG. 2 shows the external appearance of a lens-fitted film unit using the present invention. The lens-fitted photo film unit 2 is of a type designed to be made thinner, and is composed of a unit main body 3 having a photographing mechanism and the like built therein and an outer case 4 for housing the same. Outer case 4
Has a contour that exposes the winding knob 5 incorporated in the unit main body 3, and includes a strobe light emitting section 6, a shutter button 7, a photographing lens 8, and an object side viewfinder window 9.
A and a hole for exposing the number-of-shots display window 10 and the like are provided. A strobe charging switch 11 is provided below the strobe light emitting section 6.

As shown in the exploded view of FIG. 3, the unit main body 3 is composed of a main body base 12, an exposure unit 13, a strobe unit 14, a rear cover 15 and a front cover 16, which are engaged by a claw engagement. It is installed.

The body base 12 is made of opaque plastic, and a light-shielding cylinder 19 is provided on the optical axis 18. An aperture that determines the exposure range of the photographic film is formed on the back side. On both sides of the light-shielding tube 19, a cartridge storage chamber 20 for storing a cartridge,
A film roll chamber 21 for storing the photographic film in a roll shape is formed. The front surface of the outer wall of the cartridge storage chamber 20 has a shape projecting more forward than the front surface of the outer wall of the film roll chamber 21.

The strobe unit 14 is the printed circuit board 2
4 and a light emitting unit 6. Printed circuit board 24
An electric component 24a that constitutes a strobe circuit and a light emission switch 24b that is turned on by a shutter mechanism of the exposure unit 13 are attached to the. In addition, the light emitting unit 6
Is a discharge tube, a reflector, a diffuser plate 6a, and a resin holder 6b.
It was held in.

The rear cover 15 is made of an opaque plastic and has a film supporting surface 15a formed at a portion facing the aperture. Pull-top lids 15b and 15c for covering the bottom surfaces of the cartridge storage chamber 20 and the film roll chamber 21 are provided on the bottom side. The lid 15b serves as a take-out lid when taking out the cartridge containing the exposed photographic film. An eyepiece side finder window 9b is formed above the film supporting surface 15a.

The front cover 16 is made of opaque plastic, and has a shutter button 7, an object side finder window 9a, a photographing number display window 10, and a strobe charging switch 1.
1, etc. are formed. And, in the front cover 16,
A protrusion 26 is formed in accordance with the protrusion of the cartridge storage chamber 20, and the protrusion 26 serves as a grip at the time of photographing.

The exposure unit 13 includes a base 28 made of opaque plastic, a film winding mechanism,
A film counter mechanism, shutter mechanism, etc. are incorporated. Further, the taking lens 8 is incorporated in the front surface side of the base portion 28, and the finder 29 is incorporated in the upper portion of the base portion 28. A holding plate 30 made of transparent plastic is attached to the upper portion of the finder 29. The exposure unit 13 is detachably attached to the front surface of the main body base 12.

1 and 4 showing the structure of the film counter mechanism, the film counter mechanism is engaged with the perforations 32a of the photographic film 32, and is rotated once when the photographic film 32 is wound up one frame in the arrow direction. Driven sprocket 33 and this driven sprocket 3
It is composed of a cam shaft 34 which is assembled to the center of rotation of 3 and is rotated integrally, and an imaged number display plate 35 which is rotated by one scale by one rotation of the cam shaft 34. The cam shaft 34 and the number-of-photographs display plate 35 are provided in the exposure unit 13
The mechanical base 28 is rotatably attached to a bearing portion 37 and a shaft 38. The cam shaft 34 and the driven sprocket 33 are assembled when the cam shaft 34 is inserted into the mechanical base 28. Done in.

On the cam shaft 34, a one-tooth gear 40 which is a drive gear for driving the number-of-photographs display plate 35 from the upper side, a locking cam 41, a winding stop cam 42, a shutter charge cam 43, and a shaft 44 are integrally formed. ing. The winding stop cam 42 has a groove formed on the outer circumference, and when the photographic film 32 is wound up by one frame, a well-known locking lever is engaged to regulate the winding of the photographic film. The shutter charge cam 43 is for moving a well-known shutter drive lever to the shutter charge position in conjunction with the one-frame winding of the photographic film 32.

The one-tooth gear 40 has a tooth 40a formed by forming a V-shaped notch on the peripheral surface of an elliptic cylinder, and meshes with the tooth 35a formed on the outer periphery of the number-of-photographs display plate 35. The number-of-photographed image display plate 35 is rotated by one scale each time it is rotated once. Further, the locking cam 41 is slightly shifted in the rotational direction from the notch of the one-tooth gear 40 on the circumferential surface of the cylinder, and the notch 41a is formed.
Is provided, and the teeth 45a are formed on the outer circumference of the locking gear 45 that is integrally formed on the lower surface of the number-of-photographs display plate 35.
To be engaged.

As shown in FIG. 5, the teeth 45 of the locking gear 45 are
a has an arc shape, and the outer diameter of the locking cam 41 is the same as the tooth 45a of the locking gear 45. In the illustrated state, the one-tooth gear 40 and the tooth 35a of the number-of-photographs display plate 35 mesh with each other, and the locking cam 41 and the tooth 45a of the locking gear 45 mesh with each other, which is strong against the lens-fitted photo film unit 2. Even if a shock or vibration is given, the number-of-photographed display plate 35 does not rotate unnecessarily.

Further, as shown in FIG. 6, when the cam shaft 34 is slightly rotated counterclockwise, the meshing amount between the one-tooth gear 40 and the number-of-photographs display plate 35 is reduced. This is because the elliptical portion of the one-tooth gear 40 faces the teeth 35a. Conventionally, when a strong shock or vibration is applied to the lens-fitted film unit 2 in this state, the one-tooth gear 40 and the number of images to be photographed. The engagement with the display plate 35 may be disengaged, and the number-of-photographed display plate 35 may rotate. However, in this embodiment, since the locking cam 41 and the locking gear 45 maintain the meshed state shown in FIG. 5, the photographed number display plate 35 does not rotate unnecessarily.

Further, the cam shaft 34 rotates counterclockwise as shown in FIGS. 7 and 8, and as shown in FIG. 9, the tooth 40a of the one-tooth gear 40 becomes the tooth 35a of the photographed number display plate 35. When the engagement is started and the photograph number display plate 35 is started to rotate in the clockwise direction, the notch 41a of the engagement cam 41 is engaged with the engagement gear 4.
5, the engagement between the locking cam 41 and the locking gear 45 is released. As a result, the number-of-photographed display plate 35 can be rotated by one scale.

As shown in FIG. 1, a holding plate 30 is attached to the upper part of the exposure unit 13, and the holding plate 30 is provided.
Has a shaft hole 30a into which the shaft 38 of the mechanical base 28 is inserted.
And a shaft hole 30b into which the protruding shaft 44 is inserted are formed at the upper end of the cam shaft 34. Further, on the lower surface of the holding plate 30, the shaft 4 for the locking lever formed on the mechanical base 28 is provided.
A pin 30c to be inserted into the connector 7 is formed. In this way, since the holding plate 30 keeps the distance between the shafts 38, 44 and 47 constant, the engagement between the one-tooth gear 40 and the number-of-photographs display plate 35,
Also, the engagement between the engagement cam 41 and the engagement gear 45 becomes more reliable, and unnecessary rotation due to impact or the like is suppressed, so that the more accurate display of the number of captured images can be performed. A lens 30 d is formed on the upper surface of the holding plate 30 at a position above the number-of-photographed display plate 35. This lens 3
When the unit main body 3 is assembled, 0d faces the number-of-images display window 10 of the front cover 16 and enlarges and displays the number-of-images scale of the number-of-images display plate 35.

Next, the operation of this embodiment will be described. From the number-of-images display window 10 of the lens-fitted film unit 2, a number-of-images display plate 35 on which a number indicating the number of remaining images is displayed is enlarged and displayed by the lens 30d of the holding plate 30. The usage status of the film unit 2 can be confirmed. For example, the mark "." Is displayed when it is not used, and the end mark "E" is displayed when all frames are shot.

When the lens-fitted film unit 2 is not used, the photographer rotates the winding knob 5 to perform shutter charging in preparation for photographing. In the film counter mechanism before shutter charging, as shown in FIG. 5, the one-tooth gear 40 meshes with the tooth 35a of the photographing number display plate 35, and the locking cam 41 meshes with the tooth 45a of the locking gear 45. ing.
In this way, since the number-of-photos display plate 35 is meshed with the one-tooth gear 40 and the locking cam 41, it is unnecessary even when a strong shock or vibration is given to the lens-fitted film unit 2 in the unused state. It doesn't rotate easily.

As shown in FIG. 2, when the winding knob 5 is rotated counterclockwise, the spool of the cartridge which is engaged with the winding knob 5 is rotated, and the photographic film 32 is moved in the direction of the arrow in FIG. Wind up one frame. Photo film 3
By the transfer of 2, the driven sprocket 33 meshed with the perforation 32a rotates, and the cam shaft 34 engaged with this rotates in the counterclockwise direction in FIG.

When the cam shaft 34 starts to rotate, the engagement between the one-tooth gear 40 and the number-of-photographs display plate 35 is as shown in FIG.
The state becomes as shown in FIG. In this state, the amount of meshing between the one-tooth gear 40 and the number-of-photographs display plate 35 decreases, but the meshing between the locking cam 41 and the locking gear 45 is as shown in FIG.
Since the engagement state is the same as the engagement state shown in (3), unnecessary rotation does not occur even when a strong shock or vibration is applied to the lens-fitted film unit 2.

As shown in FIGS. 7 and 8, as the rotation of the cam shaft 34 progresses, the teeth 40a of the one-tooth gear 40 move to the number-of-photographs display plate 35.
Abuts on the tooth 35a. Then, as shown in FIGS. 9 and 10, the one-tooth gear 40 rotates the photographed number display plate 35 by one scale. At this time, the notch 41 of the locking cam 41
Since a has moved to a position facing the teeth 45a of the locking gear 45, the engagement between the locking cam 41 and the locking gear 45 is released, so that the number-of-photos display plate 35 rotates without any trouble. be able to.

Then, as shown in FIG. 11, since the locking cam 41 and the locking gear 45 are engaged again, the one-tooth gear 40
Even when the amount of engagement between the captured image number display plate 35 is small, the captured image number display plate 35 does not rotate unnecessarily. Further, as shown in FIG. 12, when the cam shaft 34 continues to rotate, the locking lever engages with the winding stop cam 42 (see FIG. 1) to regulate the winding of the photographic film. As described above, the lens-fitted film unit 2 that has been prepared for shooting is
The photographing range is confirmed by looking into the viewfinder window 9b on the eyepiece side, and the shutter button 7 is pressed to perform photographing. After photographing, the winding knob 5 is again rotated to wind the frame of the photographic film 32 by one frame. In this case as well, the one-tooth gear 40 and the number-of-photographs display window 35 or the locking cam 41 and the locking gear are always operated. Since any one of 45 is engaged, even if a strong shock or vibration is given to the lens-fitted photo film unit 2, the number-of-photographs display plate 35 does not shift and an accurate number-of-photographs display can be performed.

Next, another embodiment of the present invention will be described. 13 and 14 show the outline of a film counter mechanism of a lens-fitted film unit loaded with a photographic film having a novel arrangement of perforations. A bearing portion 51 and a shaft 52 are integrally formed on the upper surface of a mechanical base 50 of the exposure unit, and a cam shaft 53 and a photographed number display plate 54 are freely rotatable on the bearing portion 51 and the shaft 52. Has been inserted into. Further, inside the mechanical base 50, a driven sprocket 55 is coaxially attached to the lower end of the cam shaft 53.

The driven sprocket 55 is provided with two pairs of large teeth 57 and small teeth 58 which make a pair on the outer peripheral surface 55a in a rotationally symmetrical manner, and by the transfer of one frame in the direction of the arrow of the photographic film 59, Half turn counterclockwise in the figure (180 °)
To be done. The photographic film 59 with which the driven sprocket 55 is meshed has one large perforation 60 in which the large teeth 57 are meshed and one small perforation 61 in which the small teeth 58 are meshed for each frame of the shooting screen. The large perforations 60 and the small perforations 61 are alternately arranged in the longitudinal direction of the film, and two types of intervals, long intervals and short intervals, are alternately used. Then, one frame of the shooting screen is arranged between the large perforation 60 and the small perforation 61 arranged at long intervals, and the large perforation 60 and the small perforation 61 arranged at short intervals define the interval of each frame. It is supposed to do.

The cartridge 63 for accommodating the photographic film 59 has an outer case 63a, a spool shaft 63b and the like formed of plastic, and a film entrance / exit 64 for the photographic film 59 to enter / exit is replaced with a conventional teletemp. A plastic lid member 65 that opens and closes the film entrance / exit 64 by rotation is incorporated. In the cartridge 63, when not in use, the photographic film 59 is entirely stored up to the tip thereof, and when it is loaded into a camera or the like, the lid member 65 is first rotated so that the film entrance / exit 64.
Is opened, and then the spool shaft 63b is rotated clockwise in the figure, so that the photographic film 59 is fed out from the film entrance / exit 64.

When the film cartridge 63 is loaded in the lens-fitted photo film unit, all the photo films 59 are previously drawn out from the film cartridge 63 in the same manner as in the conventional photo film storing a 135-size photo film. The winding knob 6 loaded in the state and engaged with the spool shaft 63b every time one frame is photographed on the photographic film 59.
7 is rotated to finally wind up all the exposed photographic film 59 in the cartridge 63.

The driven sprocket 55 is stopped in a state where the large teeth 57 are meshed with the large perforations 60 at first, and positions the photographic film 59. Then, when the photographic film 59 is transferred, the large teeth 57 are urged by the large perforations 60, so that the driven sprocket 55 is slightly rotated, and the large teeth 57 are removed from the large perforations 60, and the outer peripheral surface 55a is removed. The photographic film 59 is slidably contacted. However, with this rotation amount, the small tooth 58 cannot move to the position where it meshes with the next small perforation 61.
Therefore, the cam shaft 53 assists the rotation of the driven sprocket 55 and moves the small tooth 58 to a position where it can mesh with the next small perforation 61.

The cam shaft 53 has a two-tooth gear 69, which is a drive gear, a locking cam 70, a winding stop cam 71, a shutter charge cam 72, a biasing cam 73, and a shaft 74, which are integrally formed from above. The shaft 74 is rotatably inserted into the bearing 51, and the driven sprocket 55 at the lower end is assembled.

The unwinding cam 71 has two grooves 71a on the outer circumference.
When the photographic film 59 is wound up by one frame, a well-known locking lever is engaged to regulate the winding of the photographic film 59. The shutter charge cam 72 has a pair of blade-shaped projecting portions 72a that are arranged in a rotationally symmetrical manner.
This is for moving a known shutter drive lever to a shutter charge position in conjunction with frame winding. As described above, the urging cam 73 causes the small teeth 58 of the driven sprocket 55 to move to the small perforations 61 during the film transfer.
It is a member that assists the rotation for engaging with the.
A pair of projecting portions 73a arranged rotationally symmetrically is formed on the outer periphery of the biasing cam 73. The projecting portions 73a are pressed by a biasing member (not shown), so that the cam member 53 is transferred by the film. It is rotated in the driven direction.

The two-tooth gear 69 is provided with two teeth 69a rotationally symmetrically meshed with the teeth 54a formed on the outer circumference of the number-of-photographs display plate 54, and the driven sprocket 55 is used.
When it is half-turned coaxially with, the number-of-photographs display plate 54 is rotated by one scale. The locking cam 70 is provided with a pair of notches 70a on the outer peripheral surface of the cylinder, which are slightly displaced in the rotational direction from the teeth 69a of the two-tooth gear 69, and the number-of-photographs display plate 54 is provided.
Is engaged with teeth 76a formed on the outer periphery of the locking gear 76 integrally formed on the lower surface of the. In this way, the two-tooth gear 69
Two teeth 69a and two notches 70a of the locking cam 70 are provided in rotational symmetry in order to drive each mechanism every half rotation of the cam shaft 53, for example, 1/3 rotation. The camshaft that drives each mechanism for each has three teeth and notches.

A shaft 78 is formed in the upper part of the two-tooth gear 69, and the shaft 78 is inserted into a hole 80 formed in a holding plate 79 mounted on the upper part of the mechanical base 50. Further, the holding plate 79 is also provided with a hole 81 into which the shaft 52 is inserted, so that the axial distance between the number-of-photographs display plate 54 and the cam shaft 53 is kept constant, and the two-tooth gear 69 and the number-of-photographs display plate. The engagement with 54 is made more reliable.

As shown in FIG. 15, the teeth 7 of the locking gear 76 are
6a has an arc shape, and the outer diameter of the locking cam 70 is the same as the teeth 76a of the locking gear 76. In the illustrated state, the teeth 69a of the two-tooth gear 69 and the number-of-images display plate 54
Although the teeth 54a of the lens are not meshed with each other, since the locking cam 70 and the teeth 76a of the locking gear 76 are meshed with each other, even if a strong shock or vibration is given to the lens-fitted photo film unit, the number-of-photographs display plate 54 is displayed. Does not rotate unnecessarily.

As shown in FIG. 16, when the cam shaft 53 is slightly rotated counterclockwise, the two-tooth gear 70 and the number-of-photographs display plate 54 start to mesh with each other and engage with the locking cam 70. In combination with the engagement with the stop gear 76, it is possible to more reliably prevent unnecessary rotation of the number-of-photographed image display plate 54. Further, as shown in FIG. 17, when the cam shaft 53 is further rotated, the notch 70a of the engaging cam 70 faces the engaging gear 76, and the engaging cam 70 engages with the engaging gear 76. It will be canceled. As a result, the number-of-photographed display plate 54 is rotated by one scale by the two-tooth gear 69.

When the cam shaft 53 is further rotated, the locking cam 70 and the locking gear 76 are engaged again, as shown in FIG. When the rotation of the cam shaft 53 is stopped,
As shown in FIG. 19, the two-tooth gear 69 and the number-of-photographs display plate 5
4, the arcuate surface 69b of the two-tooth gear 69 faces the number-of-photos display plate 54, but the locking cam 70 and the locking gear 76 are in mesh, so that the lens-fitted film unit is impacted. The photographed image display plate does not rotate unintentionally even when is given, and it is possible to always display a highly reliable number of images from the start of photographing of the loaded photo film 59 to the end of photographing.

In each of the above-described embodiments, the film counter mechanism of the present invention is used in the lens-fitted film unit, but it can be used in a low-priced manual winding type camera in addition to the lens-fitted film unit. Also,
Although the locking cams are provided below the drive gears and the locking gears are provided below the number-of-photographs display plate, the same effects can be obtained even if they are arranged above. Further, the one-tooth gear is formed by using an elliptic cylinder, but it is also possible to form a V-shaped notch on the basis of a cylindrical body and to project one of the V-shaped notched surfaces to the outside.

Further, the film counter mechanism which is rotated once by moving one frame of the photographic film and the film counter mechanism which is rotated halfway have been described. Rotation and 1 /
It is also possible to implement it for three rotations and further for one quarter rotation.

[0046]

As described above, in the film counter mechanism of the present invention, even when the engagement amount between the drive gear and the number-of-photos display plate is small, the engagement cam and the engagement gear mesh with each other. Therefore, even if a strong shock or vibration is given to the film counter mechanism, the number-of-photos display plate does not rotate unnecessarily, and the number of photos can be accurately displayed at all times.
Also, since the locking cam is a cylindrical body and the teeth of the locking gear are the arcuate surfaces of this cylindrical body, there is no problem with the rotation of the drive gear, and the drive gear rotates the photographing number display plate. At this time, since the engagement between the engagement cam and the engagement gear is released, the photographed number display plate can be rotated without any trouble. Further, since the axial distance between the number-of-photographs display plate and the drive gear is kept constant by the holding plate, the more reliable number-of-photographs display can be displayed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a film counter mechanism of the present invention.

FIG. 2 is an external perspective view of a lens-fitted film unit embodying the present invention.

FIG. 3 is an exploded perspective view showing a configuration of a unit main body.

FIG. 4 is a front view showing the outline of the relationship between a film counter mechanism and a photographic film.

FIG. 5 is a plan view showing a film counter mechanism when not in use.

FIG. 6 is a plan view showing a film counter mechanism immediately after film winding.

FIG. 7 is a plan view showing a film counter mechanism during film winding.

FIG. 8 is a plan view showing the film counter mechanism at the start of rotation of the number-of-photos display plate.

FIG. 9 is a plan view showing a film counter mechanism during rotation of the number-of-photographs display plate.

FIG. 10 is a plan view showing the film counter mechanism immediately after the rotation of the number-of-photos display plate.

FIG. 11 is a plan view showing a film counter mechanism near the end of film winding.

FIG. 12 is a plan view showing a film counter mechanism at the end of film winding.

FIG. 13 is a perspective view showing the configuration of a film counter mechanism according to another embodiment of the present invention.

FIG. 14 is a perspective view showing a meshing state of a driven sprocket and a photographic film of another embodiment.

FIG. 15 is a plan view showing a film counter mechanism immediately after film winding according to another embodiment.

FIG. 16 is a plan view showing a film counter mechanism in the middle of film winding according to another embodiment.

FIG. 17 is a plan view showing a film counter mechanism at the start of rotation of the number-of-photographed image display plate according to another embodiment.

FIG. 18 is a plan view showing a film counter mechanism during rotation of the number-of-photographs display plate according to another embodiment.

FIG. 19 is a plan view showing a film counter mechanism at the end of film winding according to another embodiment.

[Explanation of symbols]

 2 Film unit with lens 30, 79 Holding plate 32, 59 Photo film 34, 53 Cam shaft 35, 54 Number of shots display plate 40 One tooth gear 41, 70 Locking cam 45, 76 Locking gear 69 Two-tooth gear

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiji Uchiyama 210 Nakanuma, Minamiashigara-shi, Kanagawa Fuji Photo Film Co., Ltd.

Claims (3)

[Claims] 1. A driven sprocket that is rotated by winding up a frame of photographic film after the end of shooting, a drive gear that is provided coaxially with the driven sprocket and that rotates integrally with the driven sprocket. A film counter mechanism comprising a number-of-images display plate that is rotated by one scale by engaging a drive gear with a plurality of teeth formed along the direction of rotation. The driving gear and the locking cam that is formed integrally with the driving gear coaxially with the formed locking gear, a part of which enters into one of the teeth of the locking gear to prevent rotation of the number-of-photos display plate. A film counter mechanism, comprising: a notch formed on the outer periphery of a locking cam at a position where the number-of-photos display plate is rotated, and a tooth of the locking gear is inserted to allow rotation of the locking gear. 2. The number-of-shots display plate is formed by projecting the shaft end of the number-of-shoots display plate and the shaft end of the drive gear, and holding these shaft ends by a shaft hole provided in a holding plate. 2. The film counter mechanism according to claim 1, wherein the distance between the shaft and the shaft of the drive gear is constant. 3. The film counter mechanism according to claim 1, wherein the locking cam is formed of a cylindrical body, and each tooth of the locking gear is formed of a circular arc surface of the cylindrical body.