JPH0331936Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a device for attaching and detaching accessories such as caps and hoods that can be detachably attached to interchangeable lenses of cameras.

Prior Art Accessories that can be attached to and removed from camera interchangeable lenses, etc., are attached by forming threads on both the optical device body and the accessory and screwing them in, or by forming both parts to a size that allows them to fit into each other. There are several attachment/detachment devices that can be considered, such as ones that are held by the friction of the mating surfaces, but there is one that combines reliability (no rattling or accidental detachment) and ease of attachment. few.

A snap-type attachment/detachment device has been known as a device that combines reliability and ease of attachment. An example of a lens cap having a snap-type attaching/detaching device is shown in FIGS. 1 to 3. The lens cap is made of, for example, a synthetic resin material, and consists of a cap body 1 and a snap ring 2. The cap body 1 includes a protective surface 1a that covers the front of the lens, and an outer peripheral portion 1 formed in a generally cylindrical shape.
A pair of openings 1c are formed in the outer peripheral portion 1b at positions symmetrical to each other with respect to the optical axis of the lens to which the lens cap is attached. The opening is formed to extend in a radial direction. Further, an end surface 11 is formed on the outer circumferential portion 1b for positioning the lens cap by coming into contact with the front end surface of the lens barrel of the lens to be attached.

On the other hand, the snap ring 2 has a push button 2a that is large enough to fit into the opening, and an engaging part 2b that cannot be fitted into the opening and extends in the direction in which it is attached to the lens. A thread is formed on the outer periphery of the tip of the engaging portion 2b, and this thread is formed to fit an accessory mounting screw formed on the lens barrel. The push button 2a and the engaging portion 2
A pair of b are provided, and the pair are connected to each other by a spring portion 2c. The spring portion 2c has elasticity by being formed thin.

The pair of push buttons 2a of the snap ring 2 are fitted into the pair of openings 1c from the inside to the outside of the cap body 1, so that both are combined. In this assembled state, the spring portion 2c is slightly elastically deformed,
This urges the push button 2a and the engaging portion 2b radially outward.

In addition, Figure 3 shows the lens cap on the back side (Figure 1,
This is the view from the right direction in Figure 2). The cap body 1 is provided with a collar portion 1d that protrudes from the outer periphery of an end surface 11 that contacts the tip of the lens barrel and is fitted into the inside of the lens barrel.

To attach this conventional lens cap to the tip of the lens barrel, push the push button 2a radially inward to move the engaging part 2b together, so that the engaging part 2b fits inside the lens barrel. The lens cap and the lens barrel are aligned so that the lens cap and the lens barrel are pushed together, and after the end surface 11 comes into contact with the tip surface of the lens barrel, the push button 2a is released. The push button 2a and the engaging part 2b move radially outward due to the elasticity of the spring part 2c, and the screw formed in the engaging part 2b engages with the accessory mounting screw formed inside the tip of the lens barrel. The installation is completed.

In this attached state, this conventional attaching/detaching device is likely to be loose. That is, first, Snap Spring 2
Backlash occurs due to the gap that exists between the push button 2a and the opening 1c (necessary to facilitate attachment of the cap body and the snap ring). Since this play occurs between the snap ring 2 and the cap body 1, it does not affect the reliability of attachment of the lens cap to the lens barrel, but the play may cause discomfort or There is also a possibility that something may get caught in the gap.

On the other hand, play may also occur between the lens cap and the lens barrel. That is, when the screw of the engaging part 2b and the accessory mounting screw engage, the positions of the thread thread and the thread root change depending on the circumferential position of the screw, so when the screws are engaged with each other, they always mesh accurately. Not necessarily. The state of engagement is shown enlarged in FIGS. 4 to 6.

When the lens cap is fitted so that the end surface 11 of the outer peripheral part 1b of the lens cap is in contact with the end surface of the lens barrel 3, as shown in FIG. If they face each other accurately, when the push button 2a is released, the engaging portion 2b moves to the position shown by the broken line in the figure, and the screws mesh accurately.

On the other hand, as shown in FIG. 5, when the thread on the lens cap side faces the slope of the screw on the lens barrel side facing toward the rear of the lens barrel, when the push button 2a is released, the engaging portion 2b moves to the position indicated by the broken line in the figure. At this time, the radially outward force generated by the elasticity of the spring portion 2c acts as a force in the direction of fitting the lens cap more deeply into the lens barrel (in the direction indicated by the arrow in the figure). This force causes the outer peripheral part 1b of the lens cap to
The end surface 11 and the end surface of the lens barrel 3 come into stronger contact, and the lens cap is firmly attached. Also, at this time, the snap ring tries to move in the direction of the arrow, while the cap body is restrained by the end face of the lens barrel, so pressure is created between the push button and the inner surface of the opening, reducing play between the cap body and the snap spring. Ru.

However, as shown in FIG. 6, when the thread on the lens cap side faces the slope of the thread on the lens barrel 3 side facing toward the front of the lens barrel, the engaging portion 2b is temporarily separated by the broken line in the figure. Move to the position shown, and then move to the position shown by the dashed line in the figure. That is, the force that urges the engaging portion 2b radially outward at the position of the broken line acts as a force in the direction in which the lens cap comes out (in the direction indicated by the arrow in the figure), so the lens cap is shallow and close to the lens barrel. It will be attached to. At this time, the outer peripheral part 1b separates from the lens barrel 3 as shown by the broken line in the figure, and a gap is created between the lens barrel and the end surface 11 of the outer peripheral part 1b. This gap causes the lens cap to rattle. In order to eliminate this gap, the lens cap can then be rotated and screwed in, but the ease of attaching and detaching using the snap type will be compromised. As described above, when the accessory is attached to and detached from the screw for attaching the accessory by the snap method, looseness is likely to occur.

On the other hand, the accessory attachment part of an optical device is not a screw, but a groove or flange formed in a circumferential shape as shown in Figure 7A, and a protrusion (flange) that fits into the groove or flange is attached to the accessory. ) or recesses (grooves) may be formed. (Multiple grooves and tsuba may be used)
In this case, unlike in the case of screws mentioned above, the relative positions of the groove and collar will not change depending on the position in the circumferential direction, but unless both parts are manufactured with high precision, the fit will not be accurate. If this is not done, looseness and insufficient fit will still occur. In order to prevent this play from occurring, as shown in FIG. 7B, the inclination of the slope of the concave portion formed in the lens barrel 3 facing toward the exit direction, that is, toward the rear of the lens barrel, is made gentler. It would be better to widen the area _A1 where the top of the tsuba contacts the slope in the removal direction, but the gentler the slope, the less reliable accessory attachment will be, making it more likely that the accessory will fall off accidentally. . Therefore, in this case as well, it was impossible to reliably install it without any looseness unless the precision was increased.

Furthermore, Japanese Utility Model Publication No. 57-57369 discloses a technique for reducing rattling in a lens cap. This technology is similar to the lens cap described above, in which the cap body and the snap ring are combined, and a build-up is provided on the inner surface of the protective surface of the cap body at the position where the spring comes into contact, and the snap-ring part rides on this build-up. In particular, the spring portion is bent in the direction of the optical axis of the lens. The deflection of this spring portion causes the snap ring and the cap body to come into pressure contact at a location corresponding to the opening 1c and push button 2a of the prior art lens cap.

However, although this device can prevent looseness between the cap body and the snap ring during assembly, it cannot prevent looseness between the cap and the optical device when attaching the cap to the optical device, which increases the reliability of attachment. I couldn't do that.

Purpose This invention enables accessories for optical instruments to be attached and detached from optical instruments easily and reliably.
To obtain an attachment/detachment device that hardly causes rattling.

Summary The present invention provides an accessory for an optical device that is attached to an optical device by engagement between a concave portion and a convex portion that extend in a direction that is not parallel to the direction in which the optical device is attached.
The accessory body has a movement regulating surface that abuts against the optical device to position itself, and also includes a push button portion and an engaging portion that is integral with the push button portion and has either the recessed portion or the convex portion. A pair of removable parts are provided, and the pair of removable parts are attached to the accessory body so that they can be moved in opposite directions, and the removable parts are moved in a direction where the engaging part approaches the engaging part on the optical device side. a biasing means for engaging the concave portion and the convex portion by engaging the concave portion and the convex portion; and when the detachable portion moves according to the biasing force of the biasing device, the engaging portion is in a direction opposite to the direction in which it is attached to the optical device. The present invention is characterized in that a guide means is provided to guide the optical device in the direction, and by this movement, the concave portion or convex portion of the engaging portion and the convex portion or concave portion of the optical device are engaged with each other without play.

Embodiments Next, embodiments of the present invention will be described. 8 to 10 show a first embodiment in which the present invention is applied to the lens cap shown in FIGS. 1 to 3, and the parts common to the conventional example shown in FIGS. are given the same symbols. As in the prior art, the lens cap is made of, for example, a synthetic resin material, and consists of a cap body 1 and a snap ring 2. The cap body also consists of a protective surface 1a and an outer peripheral part 1b, and an opening 1c is formed at a position symmetrical to each other with respect to the optical axis of the lens to which the lens cap is attached, but the opening 1c is different from the opening in the conventional example. , the opening is slanted toward the front of the attached lens as it goes radially outward.

On the other hand, the snap spring 2 includes a push button 2a formed to be able to fit into the opening 1c, and a push button 2a formed to fit into the opening 1c.
As in the conventional example, a pair of engaging parts 2b are provided integrally with the push button 2a, and the two are connected by a spring part 2c.
has an inclination that matches the opening 1c so that it can fit into the opening 1c.

The cap body 1 and the snap ring 2 are assembled by fitting a pair of push buttons 2a into a pair of openings 1c from the inside in the radial direction, as in the conventional example, and in the assembled state, the cap body 1 and the snap ring 2 are assembled by the urging force of the spring portion 2c. The engaging portion 2b is urged radially outward and abuts against the outer peripheral portion 1b. The operation of attaching the lens cap to the tip of the lens barrel is similar to that of the conventional example, but the operations of the push button 2a and the engaging portion 2b are different. That is, when the push button 2a is pressed, it is pushed inward in the radial direction and pushed out toward the lens barrel along the slope of the opening 1c. Therefore, when the lens cap is fitted into the lens barrel and the push button 2a is released, the engaging portion 2b moves along the slope of the opening 1c. This operation is shown in FIG. 11, in which the engaging portion 2b moves from the solid line position to the broken line position in the figure. As shown in the conventional example, the position after this movement is such that the thread of the engaging part 2b hits the slope of the screw on the lens barrel side facing toward the rear of the lens barrel (the surface facing in the direction to prevent it from coming off). When the lens cap is in the contact position (see broken line in Figure 5), the lens cap can be attached without play, and
Play between the cap body and the snap spring is also reduced. On the other hand, when the thread of the engaging part 2b is in a position where it comes into contact with the slope of the screw on the lens barrel side facing forward of the lens barrel (see the broken line in Figure 6), the lens cap will have some play. However, the range in which this backlash occurs is smaller than in the conventional example shown in FIGS. 1 to 3.

FIG. 12 shows the range of attachment in this embodiment so that no backlash occurs. Assuming that the inclination of the opening 1c of the cap body 1 is α with respect to the radial direction, the engaging portion moves in a direction inclined by α with respect to the radial direction when the lens cap is attached. For example, the point indicated by P in the figure moves in the direction of arrow O. Therefore, in order for the thread of the engaging part to come into contact with the slope of the screw on the lens barrel side facing toward the rear of the lens barrel as described above, the top of the thread of the engaging part must be at the angle of X in the figure.
It suffices if it falls within the shaded range shown in . Therefore, the area where the lens cap can be attached without any play is the shaded area
The width of the area, that is, Aα, and the range in which backlash is likely to occur is the width of the portion other than the shaded area, ie, Bα, and Aα>Bα. At this time, the larger the angle α is with respect to the maximum angle of the slope of the screw, that is, the larger the inclination of the opening 1c of the cap body, the larger Aα and the smaller Bα, making it more difficult for play to occur.

On the other hand, when the opening 1c is not sloped, the first
As shown in Figure 2, the range in which play does not occur is the width of the shaded area Y, or A ₀ , and the range where play is likely to occur is the width of the area other than the shaded area Y, or B ₀ , and A ₀ = B ₀ . .

By tilting the aperture 1c in this way, it is possible to prevent the lens cap from rattling.

FIG. 13 shows a second embodiment of the present invention, in which the push button 2a and the engaging part 2b are connected to the protruding part 1e of the cap body 1.
It is biased radially outward by a coil spring 4 provided between the first and second embodiments, and there is no spring portion as in the first embodiment. The other configurations and operations are completely the same as in the first embodiment.

FIGS. 14 and 15 show a third embodiment of the present invention, in which the opening of the cap body is not inclined but has a separate inclined surface. That is, a protective surface 1a connected to an opening 1c provided in an outer peripheral portion 1b of the cap body 1 is formed with an inclined surface 1f that extends radially outward toward the front of the lens to which the lens cap is attached. Further, a holding portion 1g extends radially inward from the outer peripheral portion 1b, and the snap ring 2 is held between the holding portion 1g and the inclined surface 1f. In addition, the opening 1c is a push button 2a.
is formed large so that movement in the optical axis direction cannot be prevented.

On the other hand, the snap ring 2 is substantially the same as that in the first embodiment, except that an inclined surface 2d matching the inclined surface 1e is formed. The rest of the structure is completely the same as that of the first embodiment.

In this embodiment, when the push button 2a is pushed in, the snap ring 2 slides along the inclined surface 1f, moves inward in the radial direction, and moves in the optical axis direction (to the rear of the lens), while when the push button 2a is released. Since the snap ring 2 is guided by the inclined surface 1f and moves radially outward and also moves toward the front of the lens, play can be reduced as in the first and second embodiments.

In the present invention described above, the greater the inclination in the radial direction of the inclined surface formed on the cap body (that is, the larger α in Fig. 12), the smaller the range in which play occurs, and If the angle is equal to the angle of the slope, no backlash will occur. On the other hand, if the inclination becomes large, the depth of the lens cap (the size in the direction of the optical axis of the lens) must be increased, and it becomes difficult to press the push button. Therefore, the angle of inclination of the inclined surface is set in consideration of the depth of the cap and the ease with which it can be pushed in, so as to effectively reduce backlash.

In the embodiment described above, a pair of spring parts or a coil spring is used to bias the push button, but a C-shaped spring part is also formed, and both ends of the spring part are engaged with the push button. The shape may be such that a joint is formed.

Further, in the embodiment, the mounting is performed by mutual engagement of screws, but
Instead of screws, it is also possible to just have circumferential grooves and ridges formed alternately. In this case, the groove and the crest may be one each, and the groove may be formed on either the accessory mounting portion of the optical device or the engaging portion of the accessory, and the ridge may be formed on the other. Furthermore, the shapes of the grooves and ridges may not be triangular in cross section but trapezoidal in cross section.

Furthermore, the inside and outside may be reversed in the radial direction from the above embodiments, so that the accessory engaging part is on the outside and the accessory mounting part is on the inside.

In addition, as shown in the above embodiment, in the present invention, in addition to the play that occurs between the optical equipment and the protective cap, the play that the protective cap itself has (the play that occurs between the cap body and the snap ring in the example)
Although it is possible to reduce the
It is also possible to use the technique disclosed in No. 57369 in combination, and provide a built-up layer between the cap body and the snap spring to prevent backlash between the cap body and the snap spring due to its elasticity in the optical axis direction.

In the embodiments described above, the present invention was applied to a lens cap, but it can also be applied to various other devices such as a device for attaching and detaching accessories for optical equipment, such as a device for attaching and detaching a bellows attached to the tip of a lens hood and a camera lens. can do.

Effects As described above, in the present invention, in an accessory that is attached to an optical device by the engagement of a concave portion and a convex portion that extend in a direction not parallel to the direction in which the accessory is attached, the accessory body has a part that corresponds to the optical device. A pair of attachment/detachment parts are provided, each of which forms a movement regulating surface that contacts the button for positioning, and includes a push button part and an engaging part that is integral with the push button part and has one of the recessed part and the convex part. biasing the detachable part in a direction in which its engaging part approaches the engaging part on the optical device side;
A biasing means is provided that engages the concave portion and the convex portion by movement due to this biasing force, and when the detachable portion moves according to this biasing force, the detachable portion is moved in a direction opposite to the direction in which it is attached to the optical device. We have provided a guide means to guide you. For this reason, after pushing the push button part against the urging force, the movement regulating surface is brought into contact with the optical device.
When the pressure on the push button is released, the push button moves away from the optical device while being guided by the guide means due to the biasing force. When the concave part and the convex part engage each other, the movement occurs, thereby widening the positional range in which the surfaces of the concave part and the convex part facing in a direction that prevents disengagement can come into contact with each other. Therefore, even if the relative positions of the concave part and the convex part are misaligned, due to the above-mentioned surfaces coming into contact with each other, the biasing force acting on the engaging part will prevent the concave part and the convex part from disengaging and causing the accessory to fall off. This acts to prevent the movement restriction surface from coming into contact with the optical device. Therefore, according to the present invention,
It is possible to obtain an attachment/detachment device that can be easily and reliably attached, and can eliminate or reduce backlash during attachment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional attachment/detachment device, FIG. 2 is a partially enlarged sectional view of the same device, FIG. 3 is a rear view of the same device, and FIGS. 4 to 6 are explanatory diagrams of the operation of the above device. FIG. 7 is an explanatory diagram of another example of the conventional attachment/detachment device;
FIG. 8 is a sectional view of the first embodiment of the present invention, FIG. 9 is a partially enlarged sectional view of the same embodiment, FIG. 10 is a rear view of the same embodiment, and FIG. 11 is an explanatory diagram of the operation of the same embodiment. , Fig. 12 is an explanatory diagram comparing the above embodiment with the conventional attaching/detaching device, Fig. 13 is a partially enlarged sectional view of the second embodiment of the present invention, and Fig. 14 is a partially enlarged sectional view of the third embodiment of the present invention. The sectional view and FIG. 15 are partially enlarged rear views of the same embodiment. DESCRIPTION OF SYMBOLS 1... Accessory main body, 2... Detachable part, 2a... Push button part, 2b... Engagement part, 2c, 4... Biasing means, 1
c, 1e, 2d...Guide means, 11...Movement regulating surface.

Claims (1)

[Claims for Utility Model Registration] 1. Accessories that are removably attached to the front of a lens barrel and are attached by engaging a concave portion and a convex portion that extend in a direction that is not parallel to the direction of attachment to the lens barrel. , an accessory body having a movement regulating surface that comes into contact with the lens barrel to prevent the accessory from moving in the mounting direction and to position the accessory during the mounting operation on the lens barrel; a pair of push buttons; and an accessory body formed integrally therewith. a pair of engaging parts each having one of the recessed part and the convex part, and a pair of detachable parts attached to the accessory main body so as to be movable in opposite directions with respect to the optical axis of the lens barrel; By biasing the detachable parts in a direction away from each other, the engaging part and the engaging part on the lens barrel side are biased in a direction toward each other, and this biasing force engages the concave part and the convex part. a biasing means provided on at least one of the accessory main body and the attachment/detachment portion, the engaging portion being provided in at least one of the accessory main body and the attachment/detachment portion so that the engaging portion is biased according to the biasing force of the biasing means when the accessory is attached to the lens barrel. When moving closer to the engaging part on the lens barrel side,
An accessory attaching/detaching device comprising: a guide means having an inclined surface that guides the engaging part so that the engaging part moves obliquely in a direction opposite to the attachment direction. 2. The accessory according to claim 1 of the utility model registration, characterized in that the inclined surface of the guide means is formed in a pair of openings formed in the accessory body and in a push button part that fits into the openings. Attachment and detachment device. 3 The biasing means connects the pair of detachable parts with each other.
The accessory attaching/detaching device according to claim 2, which is a letter-shaped arcuate elastic member. 4. The accessory attachment/detachment device according to claim 3, wherein the biasing means includes a pair of arcuate elastic members, and the pair of attachment/detachment portions and the pair of arcuate elastic members form a substantially annular shape.