JPS62234143A - Camera having driven sprocket - Google Patents

Abstract

PURPOSE:To attain the effective utilization of a space by arranging a sprocket connected to a driving source to carry a film and a sprocket to be driven by the movement of the film on coaxial positions. CONSTITUTION:The sprocket 3 connected to the driving source to carry the film and the sprocket 4 to be driven by the movement of the film are arranged on the coaxial positions. When a driving gear 2 is rotated by the rotation of a film winding shaft, a key 2a fitted to the lower end of the gear 2 transmits the rotation to the film carrying sprocket 3 and the film is carried by sprocket gears 3A, 3B. The rotation of the sprocket 3 rotates a shutter charger gear 5 through a key 5a to set up a shutter simultaneously with the winding of the film. When the perforations of the film carried by the sprocket 3 are engaged with a sprocket gear 4B, the driven sprocket 4 starts to rotate following the movement of the film and executes rotational motion synchronized and tunned with the sprocket 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a perforated 35 mm roll film (J 135
) regarding camera sprocket mechanisms that use

[Conventional technology]

The film counter of the conventional 35-blade camera is operated via a sprocket that rotates in conjunction with the film winding shaft, and the film winding shaft winds the film that has already been photographed - outside the screen. 1 sprocket every
The film counter rotates step by step, and the number of shot frames is displayed on the outside of the camera.

[Problem that the invention seeks to solve]

In this way, conventional 35-inch cameras have a structure in which the sprocket is forcibly driven by the film winding shaft, so even when no film is loaded in the camera, the sprocket is forced to move due to the rotation of the film winding shaft. The film counter is activated, so it is impossible to judge whether there is film in the camera or not based on the film counter display.

Therefore, separate from the above-mentioned film transport sprocket, a driven sprocket that rotates in mesh with the perforations of the film to be transported is installed, for example, at the top of the screen frame, and this driven sprocket is attached as the film is transported. A proposal has been made to obtain the feed of the film counter from the rotation of the film. According to this method, the film counter will not operate unless film is loaded, and normal winding will not occur even if film is loaded. Since the film counter will not advance unless it is set, the presence or absence of film and the winding status can be easily determined.

However, in recent compact cameras, most of the space above the screen frame is used up to incorporate a range finder and an automatic rewind mechanism, so the above-mentioned driven sprocket and the drive member of the film counter connected to it, etc. Containment has become extremely difficult.

As a result of solving this problem and improving the present invention, a sprocket that rotates following the transport of the film is installed in the space occupied by the film transport sprocket, which can wind the film in balance and accurately using a pair of upper and lower sprocket gears. The object of the present invention is to provide a compact camera that makes effective use of space by allowing installation of a driven sprocket gear that can operate a film counter and the like.

[Means for solving problems]

The above object is achieved by a camera having a driven sprocket characterized in that a sprocket connected to a drive source to feed the film and a sprocket driven by the film transport are coaxially provided.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1-3.

Figure 1 shows a cross section of the sprocket used in this camera. 1 is the film advance sprocket shaft, which passes through the camera body, and its upper and lower ends are fixed by the top and bottom of the camera, respectively, so that it does not rotate. Supported. Reference numeral 2 denotes a driving gear rotatably fitted onto the upper part of the sprocket shaft 1, and is connected to a film winding shaft (not shown) serving as a driving source so as to be rotated.

Reference numeral 3 denotes a film feeding sprocket which is rotatably fitted onto the sprocket shaft 1, and is provided with a pair of sprocket gears 3A and 3B, each having eight teeth and a number, at intervals corresponding to the perforations of the film. However, the face width of the sprocket gear 3A is set to correspond to the perforation of the defined standard, whereas the face width of the sprocket gear 3B is set to the face width corresponding to the perforation of the defined standard. The dimensions are divided into two parts.

4 is a driven sprocket according to the present invention fitted to the upper end of the sprocket 3 so as to be able to rotate independently; the lower end thereof has eight teeth like the sprocket gear 3B; A sprocket gear 4B having a face width corresponding to 1 is formed.

The sprocket gears 3B and 4B are formed so that when the teeth of both gears are in phase, the outline of the tooth portion is the same as the outline of the teeth of the sprocket gear 3A.

Transmission of power to the sprocket 3 is performed as follows. That is, when the driving gear 2 rotates due to the operation of the film winding shaft described above, the key 2a at the end of the gear 2'F directs the rotation to the film feeding sprocket 3.
The film is transferred by the sprocket gears 3A and 3B. Further, the film feeding sprocket 3 is rotated by rotating the shutter charging gear 5 via a key 5a that engages with the lower end of the sprocket 3, and shank setting is performed simultaneously in parallel with film winding. It looks like this.

On the other hand, when the perforation of the film transferred by the film feeding sprocket 3 meshes with the sprocket gear 4B of the sprocket 4, the driven sprocket 4 starts to rotate following the transfer of the film,
Rotation movement is carried out in synchronization with the film feeding sprocket 3.

Therefore, the rotational operation that is exactly the same as that of the film feeding sprocket 3 is achieved by the driven gear 4A on the upper part of the driven sprocket 4.
The signal is then transmitted to the large gear 6a of the stepped gear 6 of the film counter mechanism 10 shown in FIG.

FIG. 2 shows a plan view of the film counter mechanism 10, in which numeral 11 is an index board in which the number of photographed frames is recorded, and 12 is integral with the index board 11 and has a chevron shape corresponding to the index recorded thereon. The ratchet wheels are formed with teeth and are biased counterclockwise by a torsion spring 13 so as to indicate their starting position.

Reference numeral 14 denotes an operating gear which meshes with the small gear 6b of the stepped gear 6, and is integrally formed with a somewhat thick cylindrical projection 15 at its center and a rather thin projection 16 at its upper part. A pair of notches 16a are symmetrically provided on the external surface of the protrusion 16 with a height corresponding to the teeth of the wheel 12. The operating gear 14 is pivoted so that it can swing in the longitudinal direction of the elongated hole 33 by guiding the protrusion 15 into an elongated hole on the counter board while maintaining the meshing relationship with the small gear 6b. It has become a thing of the past.

Reference numeral 17 denotes a counter set lever which is pivotally mounted on the counter board by a shaft 17a, and is biased counterclockwise by a torsion spring 18, but when the back cover is closed with respect to the camera body, Since the pressing part of the back cover presses the abutment surface 17b of the counter select lever 17 in the direction of the arrow, the counter set lever 17 rotates slightly clockwise, and its tip 17c moves away from the protrusion 16. At the same time that the torsion spring 19 mounted near the contact surface 17b is biased by the rotation of the counter set lever 17, the protrusion 16 is brought into contact with the teeth of the ratchet wheel 12 as shown in the figure. It is in a state where it is elastically pressed against.

In addition, the gear train from the driven gear 4A to the operating gear 14 reduces the rotation of the driven sprocket 4 by half and has a gear ratio of each gear so that the rotation can be transmitted to the protrusion 16 in the counterclockwise rotation direction. It is determined.

As is clear from the above explanation, Figure 2 shows the state in which film is loaded into the camera, the back cover is closed, and the film is slightly wound up. As a result of the driven sprocket 4 rotating once due to the transfer of the film, the protrusion 16 rotates counterclockwise two times.
The notch 16a rotates by one-quarter of a turn, and the ratchet wheel 1
The second tooth is advanced one equinox clockwise, and the next number of photographed frames on the index board 11 is displayed on the outside of the camera.

Due to this configuration, if an accident such as damage to the burrow or breakage of the film occurs during transport, the driven sprocket 4 will stop, the film counter 10 will become inactive, and the camera will not be loaded with film. In this case, of course, the film counter 10 does not start operating from the start position, so the film counter 10 is not only used to simply check the number of shot frames, but also serves as a means for generating film transport information. ing.

Therefore, the driven sprocket according to the present invention is suitable not only for use in the film counter 10 shown in this embodiment, but also for use in a signal generation device whose sole purpose is to generate film transport information. For example, a pulse signal generated in conjunction with the driven sprocket 4 is input to a display circuit to display the film transport status, or a change in the number of shot frames is digitally displayed on the outside of the camera by calculating the pulse signal. Furthermore, the pulse signal can be input into the camera's control circuit to issue a warning when an abnormality occurs in film transport, to perform rewinding, or to control the operation of the camera. This can also be applied as a signal.

Furthermore, when the back cover is opened from the state shown in FIG.
c pushes down the protrusion 15 of the operating gear 14 along the elongated hole 33, causing the protrusion 16 to move away from the teeth of the ratchet wheel 12.

As a result, the rotation restriction of the ratchet wheel 12 is released and the ratchet wheel 12 rotates counterclockwise together with the index dial 11 to return to its starting position.

Furthermore, due to the above-mentioned function, the driven sprocket 14 must avoid driven rotation due to friction with the film feeding sprocket 3, so a friction plate is provided on the shaft seat of the stepped gear 6 as shown in FIG. A silver plate is installed to provide rotational resistance to the stepped gear 6, thereby applying a load to the level of the driven sprocket 4, thereby preventing unnecessary rotation.

The film feeding sprocket 3 equipped with the driven sprocket 4 according to the present invention usually has upper and lower sprocket gears integrated as shown in FIG. 1, and a reel chamber R on the back of the camera body as shown in FIG. It can be installed outside the side screen frame A, but depending on the configuration of the camera, it can also be installed outside the screen frame A on the cartridge chamber P side, and if the upper and lower sprocket gears are separated. This allows them to be placed above and below the screen frame A, respectively.

〔Effect of the invention〕

According to the present invention, it is possible to arrange and accommodate a driven sprocket in the film advance sprocket space, and thereby, without increasing the volume of the camera, it is possible to obtain film transport information directly from the film. A camera with a sprocket was provided.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a sprocket of a camera according to the present invention. Second
The figure is a plan view of essential parts of the film counter of the camera. Third
The figure is a rear view of the camera body. 1... Sprocket shaft 3... Film feeding sprocket 3A, 3B, 4B... Sprocket gear 4... Driven sprocket 1o... Film counter 11...
・Index board 12...Ratchet wheel 14・
...Operating gears 15, 16...Protrusions 16
a... Notch portion 17... Counter set lever - Applicant Konishiroku Photo Industry Co., Ltd. Figure 1

Claims (6)

[Claims] (1) A camera having a driven sprocket, characterized in that a sprocket connected to a drive source to feed the film and a sprocket driven by the film transport are provided on the same axis. (2) A camera having a driven sprocket according to claim 1, wherein at least a part of the film advance sprocket and the driven sprocket are configured to engage with the same perforation of the film. . (3) A camera having a driven sprocket according to claim 1 or 2, characterized in that the camera has a film transport information generating means and the driven sprocket drives the film transport information generating means. . (4) A camera having a driven sprocket according to claim 3, wherein the film transport information means is a film counter. (5) A camera having a driven sprocket according to claim 3, wherein the film transport information generating means is means for displaying film movement. (6) The driven sprocket according to any one of claims 1 to 5, wherein a load is applied to the driven sprocket so that the driven sprocket operates only by the moving film. camera.