JP4065584B2 - sprocket - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sprocket that rotates following the transfer of a photographic film provided with perforations alternately at two intervals.
[0002]
[Prior art]
Recently, a photo film compatible with the advanced photo system, which is housed in a resin cartridge smaller than 135 type photo film cartridges and formed with two perforations per frame, a compact camera using this and a film unit with a lens (for example, “Photocopying SuperSlim” (trade name) is commercially available.
[0003]
The film winding device mounted on the lens-fitted photo film unit is provided with sprockets each having two pairs of teeth formed at positions 180 ° apart from the circumferential surface. Since the photographic film is not continuously provided with perforations, the sprocket teeth may not engage with any of the perforations, but the plate-like biasing spring provided on the device is provided coaxially with the sprocket. By pushing the cam member and rotating it in the driven rotation direction of the sprocket, the sprocket teeth are moved to a position where they can mesh with the next perforation. Then, by rotating the cam member, the shutter charge or the number of shootable images by the counter plate is displayed.
[0004]
The film winding device has a drawback that the operation of the winding knob becomes heavy because the cam member is strongly pressed by the biasing spring. In order to improve this, the urging force of the urging spring may be weakened. However, if the urging force of the urging spring is weakened, the rotation of the sprocket becomes insufficient and the next tooth comes into contact with the photographic film. There is a risk that the meshing with the perforation will fail. In order to solve this problem, the diameter of the disk-shaped part where the sprocket that meshes with the perforation at a short distance is increased, and this part is brought into contact with the flat part of the photographic film, and the sprocket is moved by the frictional force. The present applicant has proposed a sprocket and a film hoisting device that can be rotated.
[0005]
[Problems to be solved by the invention]
However, in the above sprocket, the frictional force fluctuates greatly depending on the positional relationship between the photographic film and the sprocket. Therefore, if the frictional force is small, rotation failure occurs. If the frictional force is large, the photographic film is scratched or covered with pressure. There was a problem that.
[0006]
An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a sprocket that can be surely driven and rotated by a photographic film having perforations provided at two kinds of intervals.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a sprocket body provided with a rotation center portion and a pair of perforations provided around the rotation center portion and arranged at short intervals. A sprocket is composed of at least a pair of teeth that are sequentially meshed with each other and a pressure contact portion that elastically abuts a portion of the photographic film where no perforation is provided. Thus, the film is rotated following the transfer of the photographic film.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows the appearance of the lens-fitted photo film unit 2 using the sprocket of the present invention. On the front surface of the lens-fitted photo film unit 2, a photographing lens 3, an object-side finder window 4, a strobe light emitting unit 5 that emits strobe light, a charging operation member 6 that switches on / off the strobe unit, and a view field range of the finder are switched. A finder switching operation knob 7 is provided. Further, the shutter button 8 on the upper surface, the counter window 9 for displaying the remaining number of shootable images, the opening 11 for projecting the display light guide 10 for displaying the completion of strobe charging, the winding of all the photographic films and the film cartridge A display opening 12 for displaying the completion of closing of the light shielding lid is provided. Further, from the back side of the lens-fitted photo film unit 2, a winding knob 13 that is rotated every time one frame is photographed is exposed, and the eyepiece side finder window 14 (see FIG. 3) at a position facing the object side finder window 4. Is provided.
[0009]
As shown in FIG. 3, the lens-fitted photo film unit 2 includes a main body 19 in which a film cartridge 18 including an unexposed photographic film 16 and a substantially cylindrical cartridge main body 17 is loaded, and a front surface of the main body 19. The exposure unit 20 and the flash unit 21 are assembled, and the front cover 22 and the rear cover 23 are assembled so as to cover the front side and the back side of the main body 19, and these are assembled by claw engagement.
[0010]
In the cartridge body 17, a spool 25 to which one end of the photographic film 16 is locked is rotatably incorporated, and a film feeding mechanism as disclosed in JP-A-6-266053 is incorporated. . In addition, a film-shaped light entrance lid (not shown) through which the photographic film 16 enters and exits the cartridge main body 17 is incorporated with a rod-shaped light-shielding lid 26 that opens and closes the film entrance by rotating from the outside, instead of the conventional telem. It is.
[0011]
As shown in FIG. 4, the photographic film 16 includes a film free end portion 16a, a photographing region 16b, and a film locking portion 16c. In the imaging region 16b, two large and small perforations 28 and 29 having different sizes are arranged alternately at two types of intervals along one side edge. The perforations 28 and 29 are used to set the head side and the rear side of each frame 30 in the film feeding direction. The lens-fitted film unit 2 winds the photographic film 16 into the cartridge body 17 every time it is photographed. The large perforation 28 indicates the leading side in the film feeding direction, and the small perforation 29 indicates the rear side. Each perforation 28, 29 is provided in a number corresponding to the number of frames 30.
[0012]
The end of the film locking portion 16c is locked to the spool 25, and is wound around the spool 25 by the rotation of the spool 25 by the rotation operation of the winding knob 13. The film free end portion 16a and the film locking portion 16c are regions that are not used for photographing, and are exposure-prohibited regions for use during development processing. Therefore, the film free end portion 16a and the film locking portion 16c are wound up in the cartridge body 17 in an unexposed state.
[0013]
The illustrated photographic film 17 is for a film unit with a lens by performing additional processing on a photographic film used for a general camera. The difference between the photographic film for the camera and the photographic film 17 for the lens-equipped film unit is the size of the large perforation 28 and the small perforation 31 for initial charge added within the range of the film locking portion 16c. In the photographic film for a camera, all the perforations have the same size as the small perforation 29, and the perforation 31 does not exist in the film locking portion 16c. The perforation 32 of the film free end 16a is for performing the first shutter charge when loaded in the camera.
[0014]
The main body 19 is provided with a light-shielding tube 34 that shields the photographing optical path between the exposure unit 20 assembled on the front surface side and the photographic film 16 at the center of the front surface. An aperture for defining the exposure range of the photographic film 16 is formed on the back side of the light shielding tube 34. A curved film support surface 23a is formed on the rear cover 23 so as to face the aperture. Yes. As a result, the film passage formed between the main body 19 and the film support surface 23a has a curved shape, and the photographic film 16 supported by the film support surface 23a is curved by being transferred through the film passage. Therefore, the curvature of field of the photographing lens 3 is corrected, and an image with good focus can be obtained over the entire exposure screen.
[0015]
An opening 35 is formed on the front side of the light shielding tube 34 to guide the subject light transmitted through the photographing lens 3 to the aperture. Further, an opening 34 a for exposing the sprocket incorporated in the exposure unit 20 toward the photographic film 16 is formed above the light shielding tube 34. A cartridge chamber 36 and a film roll chamber 37 in which the cartridge main body 17 and the photographic film 16 wound in a roll shape are respectively stored in the manufacturing stage are integrally formed on both sides of the light shielding cylinder 34.
[0016]
In the cartridge chamber 36 and the film roll chamber 37, the rear cover 23 is assembled on the back side of the main body 19, and the bottom cover 39 for the cartridge chamber formed integrally with the rear cover 23, and the bottom cover 40 for the film roll chamber. By closing the and, an appropriate light shielding property can be obtained. The bottom lids 39 and 40 are connected to the rear cover 23 via a thin portion that can be bent. The bottom lid 39 is opened when the film cartridge 18 is taken out from the lens-fitted film unit 2 after use. The
[0017]
A winding knob 13 is rotatably mounted on the upper portion of the cartridge chamber 36. The winding knob 13 has a gear formed on the outer periphery, and a drive shaft formed on the lower surface is engaged with the spool 25 of the cartridge body 17. Then, the photo film 16 is wound up by the spool 25 by being rotated counterclockwise in the drawing every time one frame is shot. Further, the winding knob 13 is prevented from rotating in the reverse direction by a check claw 42 formed on the upper surface of the cartridge chamber 36 being engaged with the gear.
[0018]
On the upper surface of the cartridge chamber 36, the number of rotations of the winding knob 13 is counted, and when the winding knob 13 is rotated by the amount that the photographic film 16 is entirely wound into the cartridge body 17, the light shielding lid of the cartridge body 17 is displayed. A light-shielding lid closing mechanism 44 for closing 26 is incorporated.
[0019]
The strobe unit 21 includes a printed circuit board 21 a provided with a strobe circuit and a strobe light emitting unit 5 assembled to the printed circuit board 21 a, and the switch contact piece is formed by sliding the charging operation member 6 provided on the front cover 22 upward. When 46 is brought into contact with the contact portion of the printed circuit board 21a, strobe charging is performed, and the flash is emitted in synchronization with the shutter release. The printed circuit board 21a is also provided with a metal contact piece for connecting a dry battery 47 as a power source of the strobe unit 21.
[0020]
The front cover 22 includes a front cover main body 49 in which the shutter button 8 and the display opening 12 and the like are integrally formed, a front panel 50 attached to a front center portion of the front cover main body 40, and the front cover main body 49 and the front panel. 50, a visual field switching plate (not shown) and a charging operation member 6 which are incorporated in between. The field switching plate is attached between the front cover main body 49 and the front panel 50 so as to be rotatable around the photographing optical axis, and is slid in an arc-shaped slit 51 formed in the front panel 50. It is rotated by the operation knob 7. The field switching plate is integrally formed with a plurality of viewfinder frames that are inserted and removed between the object side viewfinder window 4 and the viewfinder optical system of the exposure unit 20. These viewfinder frames limit the viewfinder view to panorama, high vision, standard view, etc.
[0021]
In addition to switching the finder field of view, the field switching plate also switches a mark printing mechanism for printing dot marks indicating the print size on the photographic film 16. The mark imprinting mechanism 53 is incorporated around the light-shielding cylinder 34 of the main body 19, and although not shown in detail, there are two imprint apertures provided so as to face the outside of the photographing range of the photographic film 16. A mark switching plate that selectively opens and closes these imprint openings, a imprint light guide that guides the mark imprinting light to the imprint openings via the mark change plate, and external light A light shielding cover that shields light from the light source, a rotation lever that transmits the rotation of the visual field switching plate to the mark switching plate, a slide lever, and the like. Note that a light emitting element attached to the back side of the printed circuit board 21a of the strobe unit 21 is used as the light for printing.
[0022]
The exposure unit 20 is assembled as a unit by assembling various parts to a plastic-molded base portion 55 and is detachably assembled to the front surface of the light shielding tube 34. A plurality of components constituting the shutter mechanism are assembled on the upper surface of the base portion 55, and an objective lens and an eyepiece lens constituting the finder optical system are assembled. A lens cover 56 for holding the photographic lens 3 is assembled on the front surface of the base portion 55. Between the lens cover 56 and the base portion 55, exposure to the photographic film 16 is performed as shown in FIG. An exposure opening 57 is formed, and a shutter blade 58 that opens and closes the exposure opening 57 is swingably assembled.
[0023]
In addition, a display light guide 10 for displaying the completion of charging of the strobe unit 21 is slidably attached to the exposure unit 20 in the vertical direction. The display light guide 10 projects outward from the upper surface of the lens-fitted photo film unit 2 in conjunction with an upward sliding operation of the charging operation member 6.
[0024]
A plurality of shafts and bearings are formed on the upper surface of the base 55, and these shafts and bearings include a cam member 60, a sprocket 61, a shutter drive lever 62, a first spring 63, a counter plate 64, A second spring 65, a locking lever 66, and the like are rotatably attached. An urging spring 67 that assists in rotation of the cam member 60 and the sprocket 61 is attached to the upper surface of the base portion 55.
[0025]
The cam member 60 is, in order from the top, a counter camshaft 68 that rotates the counter plate 64, a locking cam 69 that performs film winding with a locking lever 66, and a charge cam that rotates the shutter driving lever 62 to the shutter charge position. 70, an urging cam 71 for assisting the rotation of the sprocket 61, a shaft inserted into a bearing portion formed on the upper surface of the base portion 55 and rotatably supporting the cam member 60, and a shaft with which the sprocket 61 is engaged at the lower end It consists of the part 72, and these are integrally shape | molded with the plastics.
[0026]
Since the bearing portion (not shown) of the base portion 55 is open at the bottom, the shaft portion 72 of the inserted cam member 60 is projected. The sprocket 61 is engaged with the lower end of the protruding shaft portion 72. By attaching the exposure unit 20 to the front surface of the light shielding tube 34, the sprocket 61 is exposed toward the photographic film 16 from the upper opening 34a of the light shielding tube 34, and the photographic film 16 is engaged with and pressed against the photograph. The film 16 is rotated half a half following the transfer of one frame.
[0027]
The shutter drive lever 62 is urged counterclockwise (release position) by the first spring 63. The shutter charge cam 70 of the cam member 60 is made of a blade-shaped protrusion formed with a rotational symmetry of 180 °, and is rotated by the rotation of the sprocket 61 to press the protrusion 62a of the shutter drive lever 62 to charge in the clockwise direction. Rotate towards position.
[0028]
The locking lever 66 is urged toward the clockwise winding position by the second spring 65. When the cam member 60 rotates halfway and the groove 69a of the locking cam 69 reaches a position where it matches the claw 66a of the locking lever 66, the locking lever 66 is rotated clockwise by the urging of the second spring 65. It is moved and the nail | claw part 66a is inserted in the groove | channel 69a. As a result, the rotation of the cam member 60 is prevented, and the film winding state is established. Note that the first spring 63 and the second spring 65 have a stronger biasing force than the second spring 65 because the first spring 63 and the second spring 65 are squeezed and squeezed during assembly.
[0029]
When the locking lever 66 is rotated clockwise to engage the claw portion 66a with the winding cam 69, the engaging portion 74 protruding downward from the locking lever 66 is moved to the shutter drive lever 62. Then, it enters and engages in the rotation trajectory of the engaged portion 75 protruding upward from the position, and holds the shutter drive lever 62 in the charge position. Further, when the locking lever 66 is engaged with the winding cam 69 and the shutter drive lever 62, the winding claw 66 b is engaged with the outer peripheral teeth of the winding knob 13. Thereby, the film winding by the rotation inhibition of the winding knob 13 is performed together with the film winding by the cam member 60.
[0030]
When the shutter button 8 is pressed after the engaging portion 74 and the engaged portion 75 are engaged, the pressing rod 77 formed on the lower surface of the shutter button 8 causes the spring hooking piece 66c of the locking lever 66 to move. When pressed, the locking lever 66 is rotated counterclockwise against the bias of the second spring 65. When the locking lever 66 is rotated counterclockwise, the engagement between the engaging portion 74 and the engaged portion 75 is released, and the shutter drive lever 62 is counterclockwise due to the bias of the first spring 63. Is rotated.
[0031]
When the shutter drive lever 62 is rotated counterclockwise, the kicking arm 62b formed below the engaged portion 75 kicks one end portion 58a of the shutter blade 58. As a result, the shutter blade 58 swings clockwise about the shaft attachment portion 58b to open the exposure opening 57, and the photographic film 16 is exposed. Since the shutter blade 58 is biased toward the position where the exposure opening 57 is blocked by the spring 79, the exposure opening 57 is immediately closed.
[0032]
The counter drive shaft 68 of the cam member 60 meshes with the outer peripheral teeth of the counter plate 64. On the upper surface of the counter plate 64, a scale indicating the number of remaining shots is written. The counter drive shaft 68 advances the counter plate 64 by one scale when it rotates halfway by transferring one frame of the photographic film 16.
[0033]
The biasing cam 71 is composed of a pair of protrusions formed with rotational symmetry of 180 °, and is pressed by a biasing spring 67 assembled to the base portion 55. The urging spring 67 rotates the cam member 60 in the driven direction of the sprocket 61 by pressing the urging cam 71 and assists the rotation of the sprocket 61. The biasing spring 67 is formed of a leaf spring obtained by bending a thin metal plate. The urging force of the urging spring 67 is weak enough not to increase the operating resistance of the winding knob 13.
[0034]
As shown in FIGS. 1 and 6, the sprocket 61 includes a sprocket body 82 made of plastic and a metal spring member 83 attached to the sprocket body 82. The sprocket body 82 has a substantially rectangular rotation center 85 formed with an engagement hole 84 with which the shaft 72 of the cam member 60 is engaged, and two large pairs formed around the rotation center 85. It consists of teeth 86, small teeth 87, and pressure contact portions 88. The large teeth 86 and the small teeth 87 sequentially mesh with a short interval, that is, the large perforation 28 and the small perforation 29 between the adjacent tops 30. The pressure contact portion 88 is in pressure contact with the photographic film 16 when neither the large teeth 86 nor the small teeth 87 are engaged with the perforations. Two pairs of these large teeth 86, small teeth 87, and pressure contact portions 88 are provided around the rotation center portion 85 in a rotationally symmetrical manner.
[0035]
The pressure contact portion 88 has a substantially circular arc shape, and is elastically deformable by forming one end 88 a integrally with the rotation center portion 85 so that it can be pressed against the photographic film 16. The press contact surface 88c, which is the outer surface of the free end 88b of the press contact portion 88, has a convex shape to ensure press contact with the photographic film 16, and the pressure on the photographic film 16 is concentrated. Therefore, it is gently curved so as not to generate pressure. Further, the press contact portion 88 is formed eccentrically with respect to the rotation center so that the change in the press contact force to the photographic film 16 due to the blurring of the rotation center of the sprocket 61 is reduced.
[0036]
The spring member 83 is formed of metal, and is formed at a base 91 having an opening 90 for opening the engagement hole 84 of the sprocket body 82 and an end of the base 91, and has a large tooth 86. The engagement portion 93 that is engaged with the claw 92 formed in the inside, and between the rotation center portion 85 and the press contact portion 88 to assist the elasticity of the press contact portion 88 and to perform the creep deformation of the press contact portion 88. It consists of a spring piece 94 to prevent. Since both ends of the spring piece 94 are connected to the substrate portion 91, it is possible to reliably press the pressure contact piece 88 without plastic deformation.
[0037]
When the film is transferred while the photographic film 16 for one frame is wound up in the cartridge main body 17, as shown in FIG. 6B, after the large teeth 86 are disengaged from the large perforation 28, the press contact portion 88 is moved to the photographic film 16. Strongly pressed against the surface. Further, when the film is wound up, the photographic film 16 that has been curved by the film support surface 23a is pulled to become flat, so that the adhesion between the surface of the photographic film 16 and the press contact portion 88 becomes stronger, and the press contact portion 88. And friction between the surface of the photographic film 16 and the surface of the photographic film 16. Due to this friction, the sprocket 61 is driven to rotate counterclockwise to a standby position where the small teeth 87 abut against the photographic film 16, as shown in FIG.
[0038]
As shown in FIG. 7 showing the state of the sprocket 61 at the time of pressure contact with the photographic film 16 as a cross section, the pressure contact surface 88c of the pressure contact portion 88 is inclined. This is because the edge of the photographic film 16 in the film passage is adapted to be inclined by being pushed by the film rail 96, so that the pressure contact portion 88 is entirely pressed against the photographic film 16. Therefore, the pressure is not concentrated, and it is possible to prevent the photographic film 16 from being scratched or covered with pressure. In the state where the large teeth 86 are engaged with the large perforations 28 at the time of photographing, the photographic film 16 is not pressed by the sprocket 61, so there is no possibility of affecting the focus surface.
[0039]
Further, the small teeth 87 of the sprocket 61 are formed on the pressure contact portion 88 in order to prevent the lens-fitted photo film unit 2 from being loaded with a general camera film cartridge. . As shown in FIG. 8, in the conventional sprocket 100, when the small tooth 101 meshes with one sprocket 102, the large tooth 103 overlaps only on one side of the perforation 102 of the photographic film 104. In some cases, the photographic film 104 for a general camera can be used because it is spread and forcibly engaged. Thus, the lens-fitted photo film unit in which the photographic film is refilled is used in a very unstable state, and the reliability of the whole lens-fitted photo film unit is deteriorated.
[0040]
However, as shown in FIG. 9, in the sprocket 61 of the present invention, when the small teeth 87 mesh with one of the perforations 102, the small teeth 87 are pushed by the perforations 102, whereby the pressure contact portion 88 is elastically deformed, and the photographic film 104. Moves slightly toward the transfer direction with respect to the sprocket 61. As a result, both opposing sides of the perforation 102 overlap with the large teeth 86, so that the resistance increases and the large teeth 86 do not mesh with the perforations 102. Thereby, the refill use of the photographic film to the used film unit with a lens can be prevented.
[0041]
Next, the operation of the above embodiment will be described. A user who has purchased the lens-fitted photo film unit 2 first rotates the winding knob 13 to prepare for shooting. When the winding knob 13 is rotated, the spool 25 of the cartridge body 17 shown in FIG. 3 is rotated in the winding direction, and the film locking portion 16 c shown in FIG. 4 is wound up in the cartridge body 17.
[0042]
When the transfer of the photographic film 16 is started by this film winding operation, the photographic film 16 that has been curved by the film passage is pulled to become a flat surface, and the press contact portion 88 has its own elasticity and the spring member 83. Since the elasticity acts, the surface of the photographic film 16 is strongly adhered to the pressure contact surface 88c of the pressure contact portion 88 of the sprocket 61 as shown in FIG. As a result, friction is generated between the surface of the photographic film 16 and the pressure contact portion 88, and the sprocket 61 and the cam member 60 are reliably rotated in the driven direction by the biasing force from the biasing spring 67. As shown in (C), the small teeth 87 are moved to a standby position where they can mesh with the small perforations 31 for initial charging. Since the biasing force of the biasing spring 67 is weak enough to assist the rotation of the sprocket 61, the winding knob 13 can be operated with a light force.
[0043]
Further, as shown in FIG. 7, the pressure contact surface 88c of the pressure contact portion 88 of the sprocket 61 is inclined in accordance with the inclination of the photographic film 16 in the film passage, so that the photographic film 16 and the pressure contact portion 88 are entirely disposed. The photo film 16 is not scratched or covered with pressure.
[0044]
When the photographic film 16 is further transferred, as shown in FIG. 6D, the small teeth 87 of the sprocket 61 are engaged with the small perforations 31, and as shown in FIG. The large perforations 28 of the top 30a are sequentially meshed. The cam member 60 is rotated counterclockwise halfway between the start of the rotation operation of the winding knob 13 and the engagement of the large teeth 86 with the large perforations 28.
[0045]
While the cam member 60 rotates halfway, the charge cam 70 presses the protrusion 62 a of the shutter drive lever 62 and rotates the shutter drive lever 62 in the clockwise direction against the bias of the first spring 63. When the shutter drive lever 62 is rotated toward the charging position, the pressing by the shutter drive lever 62 is released, so that the locking lever 66 is rotated clockwise by the bias of the second spring 65.
[0046]
The locking lever 66 rotated in the clockwise direction engages the claw portion 66 a with the groove 69 a of the winding cam 69 to lock the rotation of the cam member 60, and the engaging portion 74 is engaged with the shutter drive lever 62. The moving part 75 enters the moving locus. As a result, the shutter drive lever 62 released from the press by the charge cam 70 is rotated counterclockwise by the bias of the first spring 63, and the engaged portion 75 and the engaging portion 74 are engaged.
[0047]
Furthermore, the locking lever 66 engages the winding pawl 66b with the gear on the outer periphery of the winding knob 13 to prevent the rotation operation. The counter plate 64 is rotated clockwise by the counter drive gear 68, and a scale indicating the number of remaining shots is displayed from the counter window 9. Thereby, the preparation for photographing the lens-fitted photo film unit 2 is completed.
[0048]
Thereafter, the shooting range is confirmed with the viewfinder, and the shutter button 8 is depressed. A pressing rod 77 formed integrally with the lower part of the shutter button 8 presses the spring hooking portion 66c of the locking lever 66 and rotates it counterclockwise (winding release position). As a result, the engagement between the engaging portion 74 of the locking lever 66 and the engaged portion 75 of the shutter drive lever 62 is released, and the shutter drive lever 62 rotates counterclockwise by the bias of the first spring 63. To do.
[0049]
The shutter drive lever 62 kicks and swings one end portion 58a of the shutter blade 58 that is swingably assembled between the base portion 55 and the lens cover 56 by the arm 62b. As a result, the exposure opening 57 is opened and the photographic film 16 is exposed. Further, the shutter blade 58 immediately closes the exposure opening 57 by the bias of the spring 79.
[0050]
The shutter drive lever 62 kicking the shutter blade 58 also kicks the locking lever 66 and rotates the locking lever 66 counterclockwise. As a result, the claw 66a comes out of the groove 69a of the winding cam 69, and the film winding is released. Thereafter, when the winding knob 13 is rotated in the film winding direction (counterclockwise direction), the cam member 60 is rotated halfway as described above, and the shutter charge and rotation of the counter plate 64 by one scale and film winding stop are performed. Done.
[0051]
As described above, after the shooting and film winding are repeated and the shooting of the last frame 30b is completed, all the remaining photographic film 16 including the frame 30b and the free film end portion 16a is wound into the cartridge body 17. I do. When the winding knob 13 is rotated so that all of the photographic film 16 is wound into the cartridge main body 17, the light-shielding lid closing mechanism built in the upper portion of the cartridge chamber 36 is activated to close the light-shielding lid 26 of the cartridge main body 17. To do. Further, the display opening 12 formed on the upper surface of the front cover 22 displays that the photographic film 16 has been completely wound up.
[0052]
The lens-fitted photo film unit 2 for which all photographing has been completed is handed over by a user to a development dealer or the like when requesting simultaneous printing. In the developing dealer, the film cartridge 18 is taken out from the lens-fitted photo film unit 2, the developing process and the printing process are performed, and the printed photograph and the negative film stored in the cartridge main body 17 are returned to the user.
[0053]
In some cases, the user himself removes the film cartridge 18 from the lens-fitted film unit 2 and reloads a general camera photographic film into the lens-fitted film unit 2, but as shown in FIG. Since the large teeth 86 cannot mesh with the perforation 102 of the general photographic film 104 due to the elastic deformation of the lens film, it is possible to prevent the lens-fitted photo film unit 2 from being reused accidentally.
[0054]
In the embodiment described above, two pairs of sprocket teeth and pressure contact portions are provided. However, one pair or three pairs may be provided, and one rotation or one third rotation may be performed during the transfer of one frame of film. Further, although the biasing spring is provided, the biasing spring can be omitted if the frictional force between the pressure contact portion of the sprocket and the film surface is sufficient. Furthermore, although a metal leaf spring is used as the spring member, a plastic leaf spring, rubber, or the like may be used.
[0055]
Moreover, although the said embodiment demonstrated the sprocket used for the film unit with a lens as an example, this invention is applicable also to a low-cost compact camera etc., for example.
[0056]
【The invention's effect】
As described above, according to the sprocket of the present invention, since the press contact portion that elastically presses the photographic film is provided together with the teeth that mesh with the perforations, the photographic film can be reliably transferred even when the teeth are not meshed with the perforations. Can follow and rotate.
[0057]
In addition, since another spring member is attached to the sprocket body, it is possible to assist the elasticity of the pressure contact portion and prevent creep deformation of the pressure contact portion.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a sprocket of the present invention.
FIG. 2 is a perspective view showing the appearance of a lens-fitted photo film unit using the sprocket of the present invention.
FIG. 3 is an exploded perspective view showing a configuration of a lens-fitted photo film unit.
FIG. 4 is a front view of the film cartridge.
FIG. 5 is an exploded perspective view showing configurations of a shutter mechanism, a film winding mechanism, a film winding mechanism, and a counter mechanism.
FIG. 6 is an explanatory view showing a rotation state of a sprocket by transferring a photographic film.
FIG. 7 is a cross-sectional view of a main part of a film unit with a lens showing a state in which a sprocket is pressed against a photographic film.
FIG. 8 is an explanatory view showing a state of engagement between a conventional sprocket and a photographic film for a camera.
FIG. 9 is an explanatory view showing a meshed state between the sprocket of the present invention and a photographic film for a camera.
[Explanation of symbols]
2 Film unit with lens
16 Photo film
17 Cartridge body
20 exposure units
28 large perforations
29 Small perforations
61 Sprocket
82 Sprocket body
83 Spring member
86 large teeth
87 small teeth
88 Pressure weld

Claims (6)

In a sprocket having perforations alternately arranged at two kinds of intervals and rotating in accordance with a photographic film transported in a film passage,
A rotatably supported rotation center portion,
At least a pair of teeth that are provided on the peripheral surface of the rotation center portion, and sequentially mesh with each other when the pair of perforations arranged at short intervals move to rotate the rotation center portion ;
Perforation of the photographic film is provided on the peripheral surface of the rotation center and on the downstream side in the rotation direction of the pair of teeth so as to be elastically deformable, and when the engagement of the pair of teeth with the pair of perforations is released. characterized in that a pressure contact with the portion not provided, the pair of teeth by friction at that time and a pressure contact portion for rotating the rotation center portion to come in engagement can be positioned next to the perforation sprocket. The pressure contact portion has one end formed integrally with the rotation center portion so as to be elastically deformable, and a free end disposed on the downstream side in the rotation direction of the pair of teeth and pressed against the photographic film. The sprocket according to claim 1. The pressure contact portion has one end formed integrally with the rotation center portion so as to be elastically deformable, and a free end disposed on the downstream side in the rotation direction of the pair of teeth and pressed against the photographic film. 2. The sprocket according to claim 1 , wherein elasticity of the free end is assisted by a spring member attached to the rotation center portion . The sprocket according to claim 2 or 3 , wherein the one end of the press contact portion is provided on a peripheral surface of the rotation center portion . The press contact surface that is provided at the free end and presses against the photographic film is inclined in accordance with the inclination of the photographic film generated when the film is pushed by a film rail in the film passage. Item 5. A sprocket according to any one of Items 2 to 4 . Wherein the pair of at least one tooth of the teeth is provided integrally with the press-contact portion, the contact portion is elastically deformed at the downstream side in the rotational direction when the teeth are pressed in mesh with the perforations, the teeth due to the elastic deformation the downstream side in the rotation direction, and claims 1 to 5 sprocket according to any one the photographic film and wherein Rukoto is moved respectively on the downstream side of the transport direction.

Images