JPS6128187Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention relates to the back cover opening/closing device of a camera, especially
This invention relates to a back cover opening/closing device that uses a spool knob to open the back cover of a camera that uses roll film such as 120 film.

Conventionally, in cameras that use roll film that is wound around a spool and has light-shielding leader paper on the front and back, the spool knob for taking out the spool from the camera and the opening/closing knob for opening and closing the camera back were provided separately. To remove the finished film from the camera, first wind the film, completely shield it from light with the leader paper at the rear, open the back cover by operating the back cover opening/closing knob, and then hold the leader paper by hand to prevent it from loosening. It is necessary to pull out the spool knob and take out the film while holding it down, which is a complicated operation and takes time to change the film.Not only is there a risk of losing the shot in an emergency, but it also reduces the number of parts and assembly man-hours. This has the drawback of increasing production costs. On the other hand, with cameras that use 135 film, the film is rewound after shooting and is stored inside the cartridge, completely shielding it from light, so there is no risk of light leakage, and by pulling out the rewind knob all the way, the film can be rewound. A cartridge retrieval device that also functions as a back cover opening/closing device is often used, which allows the cartridge to be taken out by opening the lid and pulling it out one more step.

However, in cameras using roll film, a friction roller is provided that presses against the outer periphery of the wound film from the inside, and the amount of film feed is regulated by detecting the rotation angle of this friction roller. Therefore, if you open the back cover and take out the film by pulling out the spool knob, as with a camera using 135 film, the pressure of the friction roller mentioned above will remove the unsealed film that has already been photographed at the same time as the back cover is opened. There is a risk that the stopper film will pop out and the leader paper, which has a tendency to relax, will loosen, causing light leakage from the film.

This idea was made in view of the above points,
Opening the back cover and taking out the film is done using a single spool knob, which improves operability and reduces the number of parts, while also preventing light leakage from the film due to the film being accidentally ejected. It is an object of the present invention to provide a back cover opening/closing device that can prevent such damage.

Therefore, the camera back cover opening/closing device according to this invention has a spool knob mounted concentrically with the spool shaft that rotatably supports the roll film spool so that it can be relatively displaced in the axial direction, and the spool knob can be moved out of the neutral position. The spool shaft moves in the same direction as the spool shaft moves in the opposite direction, but does not move in the same direction as the spool shaft moves inward.In addition, the back cover opening/closing lever, which is always biased in the locking direction, is linked to the spool knob, and the spool shaft By pushing in, the back cover opening/closing lever is driven in the unlocking direction against the biasing force, and the back cover is opened.
By pulling out the spool shaft, the spool shaft is retracted and disengaged from the spool.

Embodiments of this invention will be described below with reference to the accompanying drawings.

Figure 1 shows the oblique rear view of a twin-lens reflex camera to which this invention has been applied.A back cover 2 is pivotally attached to a camera body 1 with a shaft 3, and a spool knob 4 that also serves to open and close the back cover is located at the top of the left side. It is slidably mounted on a bearing 5.

As shown in FIGS. 2 and 3, the spool knob 4 has a plurality of legs 4a having the same length that loosely fit into corresponding grooves 5a of the bearing 5 and pass through the inside of the bearing 5. 1 and biases the spool knob 4 outward, and when the spring 6 comes into contact with the inner end surface 5b of the bearing 5, the biasing force on the spool knob 4 is stopped.

A spring 8 is fixed between the bearing 5 and the spool shaft 7, which has an outer peripheral surface that is coaxial with the bearing 5 and has an outer peripheral surface that is slidable on the inner peripheral surface 1a of the camera body 1 and has an inner diameter equal to the inner peripheral surface of the bearing 5. A disk 10 is fixed to one end of the spool shaft 7 with a screw 9, and as the disk 10 comes into contact with the end surface of the bearing 5, the inner part of the spool shaft 7 is pressed inward. Prevent the biasing force in the direction. In addition, a stepped portion 4 is provided on the inner peripheral surface of the spool knob 4.
b and 4c are provided to serve as contact surfaces for the disk 10 and end plate 11.

Next, 1 on the tip end surface of the leg 4a of the spool knob 4.
One end of the back cover opening/closing lever 12, which is slidable left and right, is engaged with the spring 13.
A claw 12a is provided so that the claw 2a fixed to the back cover 2 can be locked in the closed state.

Furthermore, with the threaded shaft 14 and the long hole 15a,
A lock pawl 15 with a release knob 16 is attached to the camera body 1 so as to be able to slide up and down, and a spring 17 applies an upward biasing force, and the protrusion 15b is inserted into one of the legs 4a of the spool knob 4. You can move freely within the route.

This embodiment has the above-mentioned configuration, and as shown in FIG. Since the stepped portion 4b is pressed and the biasing force of the spring 6 is blocked by the inner end surface of the bearing 5, the spool knob 4 is maintained at the neutral position.

When the release knob 16 is pressed downward as shown by arrow A in FIG. 5 from the closed state of the back cover shown in FIGS. 1 and 3, and the lock pawl 15 is moved downward against the spring 17, the projection 15b is leg 4 of spool knob 4
Evacuate from the approach path of a.

In this state, spool knob 4 in the neutral position
When the spool shaft 7 is pushed inward against the spring 6 as indicated by the arrow B in FIG. Since it moves to the right (see Figure 4), the claw 12
a is disengaged from the pawl 2a, and the back cover 2 is rotated to the right about the shaft 3 by a film compression plate spring (not shown), and is in an open state as shown in FIG.

In addition, FIG. 5 shows the release knob 16, the back cover opening/closing lever 12, and the spool knob 4 after the camera back 2 is opened.
The figure shows the state where it has returned to its original position.

Next, while pressing the outer peripheral surface of the leader paper with one hand, pull out the spool knob 4 to the left with the other hand as shown in FIG. Therefore, the spool shaft 7, which is integral with the disk 10, also moves to the left against the spring 8, and the spool 18 is unscrewed, and as shown in FIG. 20 is pushed out.

Here, the film 20 is taken out while gripping the outer peripheral surface of the leader paper so as not to loosen, and sealed with the attached seal.

Note that when the spool knob 4 is pulled out and slightly rotated left and right, the end of the leg 4a engages with the step 5c of the bearing 5 (see FIG. 2), causing the spool knob 4 to resist the spring 8. The spool 18 can be easily replaced by holding the spool 18 in the drawn state.
When rotated in the opposite direction, the force of the spring 8 returns to the neutral position shown in FIG. After moving only the back cover opening/closing lever 12 to the right, it is moved to the left again by the spring 13, and the claw 2
a, 12a are engaged, and the back cover 2 is in a closed state.

In this state, the leg portion 4a of the spool knob 4 is locked by the protrusion 15b of the lock pawl 15, so there is no risk of inadvertently pushing the spool knob 4 from the neutral position and leaking light onto the film.

In the above example, the case where this invention was applied to the back cover opening/closing device of a twin-lens reflex camera was explained, but this invention can also be applied to other types of cameras that use roll film such as 120, 220, and 127 film. It goes without saying that it is possible.

As described above, according to this invention, the spool shaft is mounted inside the spool knob so as to be displaceable in the axial direction, and when the spool knob is displaced outward, the spool shaft is moved inwardly. The spool knob is connected to the back cover opening/closing lever so that it does not move at the same time as the camera is displaced, so pressing the spool knob inward drives the back cover opening/closing lever and opens the back cover. By pulling out the spool knob, the spool shaft can be removed from the spool, ensuring safety against light leakage of the film and significantly improving operability when changing the film.

Furthermore, since opening/closing the back cover and replacing the spool are done with the same part, the number of parts and assembly man-hours are reduced, which reduces production costs and has the excellent effect of organizing external parts and improving the appearance. .

[Brief explanation of the drawing]

Figure 1 is a rear perspective view of a twin-lens reflex camera to which this invention is applied, Figure 2 is an exploded perspective view showing an embodiment of this invention, Figure 3 is a sectional view showing its steady state, and Figure 4 is FIG. 5 is a cross-sectional view showing the back cover in an open state, FIG. 5 is a rear perspective view thereof, FIG. 6 is a cross-sectional view showing the spool taken out state, and FIG. 7 is a rear perspective view thereof. 1...Camera body, 2...Back cover, 4...Spool knob, 7...Spool shaft, 12...Back cover opening/closing lever, 15...Lock claw, 16...Release knob, 18...Spool.

Claims (1)

[Scope of utility model registration request] In a camera that uses a roll film that is wound around a spool and has light-shielding leader paper on the front and back, a spool knob is mounted so as to be relatively displaceable in the axial direction concentrically with a spool shaft that rotatably supports the spool. The above-mentioned spool shaft moves together with the outward displacement of the knob from the neutral position, but does not move together with the inward displacement, and the back cover opening/closing lever, which is always biased in the locking direction, is moved with the above-mentioned spool shaft. The device is connected to a spool knob, and when the spool knob is pressed, the back cover opening/closing lever is driven in the unlocking direction against the biasing force to open the back cover, and the spool shaft is retracted by pulling it out. A back cover opening/closing device for a camera, characterized in that the device is configured to release the engagement with the spool.