JP3100468B2 - Feed detection device for long strips - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting the feeding of a long strip such as a film.

[0002]

2. Description of the Related Art In automatic winding cameras and projectors,
Control is performed to detect the amount of film feed and to operate and stop the film feed mechanism.To achieve this, a feed detection device for a long strip like a film is provided to reduce the amount of film feed. Need to detect.

A collapsible miniature camera equipped with a conventional long band-shaped feed detecting device of this kind is configured as shown in FIG. 9 or FIG. 9 and 10, reference numeral 11 denotes a camera body, and a cartridge chamber 13 for accommodating a film cartridge 12 is formed at one end of the camera body 11, and a film winding mechanism is provided at the other end of the camera body 11. A film chamber 14 is formed. A back cover 15 is attached to the back surface of the camera body 11 so as to be openable and closable, and a film pressure plate 17 is attached to the inner surface of the back cover 15 via a leaf spring 16. With this configuration, the film 18 housed in the film cartridge 12 is wound and fed by a film winding mechanism provided in the opposite film chamber 14 along the pressing surface of the film pressure plate 17.

[0004] Reference numeral 20 denotes a lens barrel.
20 has a lens group 21 for photographing. This lens barrel 20
Indicates the camera body when not taking a picture,
It is configured as a so-called collapsible type that retracts inside 11.

Reference numeral 23 denotes a sprocket for detecting a feeding state. As shown in FIG. 14, which is a longitudinal sectional view of a supporting portion of the sprocket 23, bearings 11a, 11 on the camera body 11 side.
In FIG. 10, a plurality of six teeth 23a are formed on the outer peripheral surface of the outer peripheral surface. As shown in FIGS. 11 to 13 in which the sprocket 23 portion in FIG. 10 is enlarged, perforations 24 which are engaging holes for feeding formed regularly in the longitudinal direction of the teeth 23a and the film 18.
, The film 18 is driven to rotate with the feeding operation of the film 18.

A sprocket gear 23b is formed around the shaft of the sprocket 23, and meshes with a counter gear 25 as shown in FIG. Counter gear
25 has a counter cam 26 integrally as shown,
When the sprocket 23 rotates counterclockwise with the feeding of the film 18, the counter gear is rotated via the sprocket gear 23b.
25 and the counter cam 26 integral therewith rotate clockwise. The contact pieces 27a and 27b of the counter switch 27 are disposed on the rotation locus of the counter cam 26, and are driven to open and close as shown in FIGS.

Here, the gear ratio between the sprocket gear 23b and the counter gear 25 is usually set to 2: 3, and one frame of the film 18, that is, 8 of the perforations 24 is used.
The counter gear 25 makes one rotation per unit. Therefore,
The counter switch 27 is turned on every time the film 18 is fed by one frame, and controls the stop of a film feeding motor (not shown).

In the above arrangement, when a film feeding motor (not shown) is operated and the film 18 is wound and moved by the film winding mechanism in the film chamber 14 shown in FIG. 9 or FIG. As shown by, the right side of the perforation 241 meshed with the teeth 23a1 of the sprocket 23 contacts the right surface of the teeth 23a1, and rotates the sprocket 23 counterclockwise. When the sprocket 23 rotates to the state shown in FIG. 12, the next tooth 23a2 enters the next perforation 242, and the rotation continues to the state shown in FIG. FIG. 13 shows a state in which the film 18 has been fed by one frame, the counter switch 27 is turned on, and the film feed motor (not shown) is controlled to stop as described above.

In recent years, there has been a strong demand for downsizing, especially thinning of cameras. As described above, a retractable structure in which the lens barrel is retracted into the camera body when not in use has been adopted. I have. When such a collapsible structure is adopted, a major problem is how large the collapsible amount of the lens barrel in the camera body can be secured.

In the structure shown in FIG. 10, since the sprocket 23 having a relatively large diameter is located on the rear surface of the lens barrel 20, the rear ball of the lens group 21 provided on the lens barrel 20 hits the sprocket 23. So, the amount of collapsing is limited,
Large collapsing was difficult.

To solve such a problem, it is conceivable to reduce the diameter of the sprocket 23. On the other hand, since the pitch of the perforations 24 provided on the film 18 is a predetermined value, if the diameter of the sprocket 23 is reduced, the number of teeth 23a engaged with the perforations 24 must be reduced to secure the pitch of the teeth 23a. Have to be.
For example, in the conventional example shown in FIGS. 10 to 13, the number of teeth 23a of the sprocket 23 is six, but when the diameter is reduced, the number of teeth 23a is reduced to four as shown in FIG. We have to secure the pitch by reducing it.

However, if the number of teeth 23a of the sprocket 23 is reduced, the state of FIG.
In the state of 6, the film 18 may slip on the teeth 23a1 previously engaged with the perforations 241 and the next teeth 23a2 may not enter the next perforations 242. is there. For this reason,
It was practically difficult to reduce the number of teeth 23a of the sprocket 23 to six or less to reduce the diameter of the sprocket 23.

Further, as shown in FIG.
Is positioned outside the camera aperture, and rollers 29
If the film 18 is held down by the rollers 29, the amount of engagement between the perforations and the teeth 23a of the sprocket 23 increases, so that a sprocket with four teeth can be used, but the width of the camera is limited. The size of the camera becomes large, which is not preferable from the original purpose of reducing the size of the camera.

[0014]

As described above, since the diameter of the sprocket 23 for detecting the feeding state of a long strip of film or the like is relatively large, it is difficult to reduce the size of the sprocket 23. However, there is a problem that it is difficult to reduce the thickness of the camera due to restrictions on the amount of collapse.

An object of the present invention is to provide a long strip which can reliably detect the feeding state of the long strip even if the diameter of the sprocket for detecting the feeding state of the long strip is reduced. An object of the present invention is to provide a feed detecting device.

[0016]

According to the present invention, the movement of a long strip having a plurality of engagement holes regularly arranged in the longitudinal direction is detected by the rotation speed of a sprocket meshing with the engagement holes. A plurality of sprockets are provided in a positional relationship to mesh with the engagement holes, respectively, and the plurality of sprockets are in different engagement phases with the engagement holes. And an interlocking mechanism for interlocking with each other.

[0017]

According to the present invention, a plurality of sprockets are interlocked with each other in a state where the engagement phases with the engagement holes are different from each other. , And the feeding state of the long strip can be reliably detected.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a long strip feeding detecting device according to the present invention.

First, the structure of a collapsible camera using an embodiment of a long strip-shaped sheet feeding detecting apparatus will be described with reference to FIG. Note that the same parts as those of the conventional device are denoted by the same reference numerals and described.

As shown in FIG. 6, a camera chamber 11 for accommodating a film cartridge 12 is provided at one end of a camera body 11, and a film chamber 14 having a film winding mechanism is provided at the other end of the camera body 11. A back cover 15 is attached to the back surface of the camera body 11 so as to be openable and closable, and a film pressure plate 17 is attached to the inner surface of the back cover 15 via a leaf spring 16. With this configuration, the film 18 as a long band-shaped body accommodated in the film cartridge 12 is wound up and fed toward the opposite film chamber 14 by the winding mechanism. On the other hand, the lens barrel 20 integrally has a lens group 21 for photographing, and is retracted into the camera main body 11 during non-photographing, that is, collapsed by a reciprocating mechanism (not shown).

Reference numeral 31 denotes a feeding detecting device for a long strip-shaped body.
The feed detecting device 31 will be described using the above-described film 18 as an example of a long strip. As shown in FIG. 1 to FIG.
The sprockets 32 and 33 are provided. Further, in the longitudinal direction of the film 18, perforations 24 are formed as engaging holes regularly arranged at a predetermined pitch, and the sprockets 32 and 33 are in a positional relationship capable of meshing with the perforations 24, respectively. They are juxtaposed as shown.

Here, each sprocket 32, 33 is shown in FIG.
Or smaller in diameter than the conventional sprocket 23 shown in FIG. On the other hand, since the pitch of the perforations 24 is a predetermined value, the number of the teeth 32a and 33a meshing with the patrone 24 is set to four to secure the predetermined pitch.

As shown in FIG. 4, the sprockets 32, 33 are rotatably supported in a vertically oriented state by bearings 11a, 11b of the camera body 11, as shown in FIG. Gears 34 and 35 are integrally provided below the shaft. The interval between the sprockets 32 and 33 is set to 2.5P, where P is the pitch of the perforations 24.

Further, a counter gear 36 which functions as an interlocking mechanism for interlocking the sprockets 32 and 33 is provided between the sprockets 32 and 33. The counter gear 36 integrally has a counter cam 37, and as shown in FIG.
The bearings 11c and 11d are rotatably supported in a vertically oriented state. The counter gear 36 meshes with the gears 34, 35 integral with the sprockets 32, 33 at a gear ratio of 1: 2. The contact pieces 27a and 27b of the counter switch 27 are arranged on the rotation locus of the counter cam 37 in the same manner as in the related art, and are shown in FIGS. Is driven to open and close.

Here, the sprockets 32 and 33 are set so that the phases of their teeth 32a and 33a are shifted by 45 °.
The gear is engaged with the counter gear. Therefore, the sprockets 32, 33 rotate in conjunction with each other with their phases shifted by 45 °.

In the above configuration, the film in the state of FIG.
When 18 is fed from the right to the left by a winding mechanism (not shown), the perforations 24 are attached to the right surface of the teeth 33a1 of the sprocket 33 engaged with a certain perforation 244.
The right side of 4 comes into contact, and the sprocket 33 is rotated counterclockwise. With the rotation of the sprocket 33, the counter gear 36 rotates clockwise via a gear 35 integral with the sprocket 33, and further via the gear 34 meshing with the counter gear 36, the other sprocket 32 rotates counterclockwise. That is, both sprockets 32 and 33 rotate in conjunction with each other.

By this rotation, the teeth 32a1 of the other sprocket 32 enter the perforations 242 as shown in FIG. Then, as the film 18 continues to move to the left, the right side of the perforation 242 comes into contact with the right surface of the tooth 32a1, and this time rotates the other sprocket 32 counterclockwise.

As described above, the teeth 32a of the sprocket 32 and the teeth 33a of the sprocket 33 are alternately engaged with the perforations 24 of the film 18 with a phase difference of 45 °, so that the sprockets 32, 33 do not come off from the perforations 24 without fail. And the counter gear 36 is rotated. Counter gear 36 and counter cam integrated with counter gear 36
37 is set so as to make one rotation for every two rotations of both sprockets 32 and 33 depending on the gear ratio.
1 rotation, that is, one rotation per eight perforations 24.

Here, in the state of FIGS. 1 and 2, the counter switch 27 is in the off state, but in the state of FIG. 3, the counter cam 37 comes into contact with the contact piece 27a,
The switch 27 is turned on by pressing 37 against the contact piece 27b.
That is, the switch 27 is turned on for each rotation of the counter cam 37, for example, for each frame of the film, and outputs one pulse signal. When this pulse signal is input to an electric circuit (not shown), it is detected that the film 18 has been fed by one frame. Therefore, it is possible to stop the winding motor (not shown) to stop the feeding of the film 18. it can.

As is apparent from the above description, the number of teeth 32a, 33a of the sprockets 32, 33 is smaller than that of the conventional sprocket.
As shown in FIG. 6, when incorporated in a retractable camera, a larger retractable amount of the lens barrel 20 can be obtained as compared with the same type of camera shown in FIG. As a result, the thickness of the entire camera can be reduced. Although the thickness of the sprocket portion in the conventional example shown in FIG. 10 was 10.45 mm, for example, FIG.
According to the above-described embodiment, the thickness of the sprocket portion is reduced to, for example, 7.25 mm, and the retracted amount of the lens barrel 20 can be increased. Although the number of sprockets is increased by one in the embodiment of FIG. 6 as compared with the conventional example shown in FIG. 10, there is no problem since the sprocket is usually a molded plastic product and can be formed at low cost.

In the above embodiment, the sprockets 32, 33 have a four-tooth configuration with four teeth 32a, 33a. However, as shown in FIGS. 7 and 8, the number of teeth 32a, 33a is increased. The sprockets 32 and 33 may be further reduced in diameter by using a three-tooth structure having three teeth. Thus 3
In the case of the tooth configuration, the thickness of the sprocket portion can be reduced to, for example, 5.586 mm.

In this case, the sprockets 32, 33 are set so that the meshing phases of the teeth 32a, 33a of these sprockets 32, 33 with the perforations 24 are shifted by 60 °, and are linked by a counter gear 36. With this setting, one of the sprockets 32 and 33 always meshes with the perforation 24, so that the movement of the film 18 can be reliably detected. Also, film 1
By movement of 8 perforations per frame for 24 minutes, the sprockets 32 and 33 rotate 8/3, and the counter gear 36 rotates twice. Therefore, two pulses are output from the counter switch 27 for each frame of the film, so that the winding motor can be controlled by this.

Although all of the above embodiments are directed to the detection of film feed in a camera, the present invention can also be applied to the detection of film feed in a projector. Furthermore, it is not limited to film,
The present invention can also be applied to a movement detecting device for a long band-shaped body having holes at a constant pitch, for example, a fan-folded paper, and is very effective in miniaturizing these. Although the leaf switch has been exemplified as the counter switch 27, a switch such as a photo interrupter or another type of switch may be used.

[0034]

According to the feed detecting apparatus for a long body according to the present invention, a plurality of sprockets are interlocked with each other in a state where the engagement phases with the engagement holes are different from each other.
Any one of the plurality of sprockets always engages with the engagement hole of the long band-shaped body, which enables the sprocket to be reduced in diameter, and ensures the feeding state without coming off from the engagement hole of the long band-shaped body. Detection can be performed, and both miniaturization and reliable detection of the device can be achieved.

[Brief description of the drawings]

FIG. 1 is a plan view showing an operation process of an embodiment of an apparatus for detecting feeding of a long band-shaped body according to the present invention.

FIG. 2 is a plan view showing the next operation process shown in FIG. 1;

FIG. 3 is a plan view showing the next operation process shown in FIG. 2;

FIG. 4 is a longitudinal sectional view of a sprocket portion of the feed detecting device.

FIG. 5 is a longitudinal sectional view of a counter gear portion of the feed detecting device.

FIG. 6 is a plan sectional view showing a case where the feed detecting device is applied to a camera.

FIG. 7 is a plan view showing an operation process of a feed detecting device according to another embodiment of the present invention.

FIG. 8 is a plan view showing the next operation process shown in FIG. 7;

FIG. 9 is a plan sectional view showing a case where a conventional feed detecting device is applied to a camera.

FIG. 10 is a plan sectional view showing a case where another conventional feed detecting device is applied to a camera.

FIG. 11 is a plan view showing an operation process of a conventional feeding device.

FIG. 12 is a plan view showing the next operation process shown in FIG. 11;

FIG. 13 is a plan view showing the next operation process shown in FIG. 12;

FIG. 14 is a longitudinal sectional view of the sprocket part.

FIG. 15 is a plan view showing one operation process of a conventional feeding device.

FIG. 16 is a plan view showing the next operation step shown in FIG. 15;

[Explanation of symbols]

 18 Film as a long strip 24 Perforation as an engagement hole 31 Feed detection device 32, 33 Sprocket 36 Counter gear as interlocking mechanism

Claims (1)

(57) [Claims] 1. The feeding of a long strip which detects the movement of a long strip in which a plurality of engagement holes are regularly arranged along a longitudinal direction by the number of rotations of a sprocket meshing with the engagement holes. In the detecting device, a plurality of the sprockets are provided in a positional relationship to mesh with the engagement holes, and an interlocking mechanism that interlocks the plurality of sprockets with each other in a state where the engagement phases with the engagement holes are different from each other. A feeding detecting device for a long strip-shaped body, which is provided.