JPH11352545A - Accessory attaching structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach and detach an accessory and to use all the screwing type accessories, by simple and inexpensive constitution. SOLUTION: When an operation ring 38 is set at a retreat limit position and a finger is released from the ring 38 in a state that a male screw 1406 of a filter 12 is inserted in the leading part of a lens barrel 22, the ring 38 is advanced by the energizing force of a coil spring 40 and is set at an advance limit position. At this time, when three holding bodies 34 are closed from an open state as the ring 8 is advanced and the ring 38 reaches the advance limit position, the engaging part 3402 of the holding body 34 is meshed with the screw 1406 of the filter 12. Since the ring 38 is energized toward the advance limit position by the spring 40 and held at the position, the filter 12 is attached to the leading part of the lens barrel 22 coaxially with the lens barrel 22. When the ring 38 is positioned at the retreat limit position, three holding bodies 34 can be rocked outwards and opened by a twist spring 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a mounting structure of an accessory attached to a tip of a lens barrel such as a camera or an interchangeable lens.

[0002]

2. Description of the Related Art In addition to filters, hoods, teleconverters, and wide converters, there are also adapters such as reverse adapters as accessories attached to the tip of a lens barrel such as a camera or an interchangeable lens. For example, if the accessory is a filter, various filters according to the purpose of use, such as a lens protection filter, a soft filter, a skylight filter, and a cross-type filter, can be detachably mounted in front of the taking lens. Have been. This type of filter is generally screw-on,
A male screw formed on the filter frame is screwed into a female screw formed on the inner periphery of the distal end of the lens barrel to be attached to the lens barrel.

[0003]

Therefore, in the conventional filter mounting structure, it takes a long time to screw in and sometimes misses a photo opportunity. Although a bayonet filter is also provided as a filter that can be easily attached and detached, it is expensive because a bayonet mechanism is provided on the filter side. However, there is a problem that the types of filters that can be used are limited. The present invention has been devised in view of the above circumstances,
SUMMARY OF THE INVENTION It is an object of the present invention to provide an accessory mounting structure in which accessories such as a filter can be easily mounted and removed by a simple and inexpensive configuration, and all conventional commercially available screw-in accessories can be used. It is in.

[0004]

According to the present invention, there is provided an accessory mounting structure for detachably mounting an accessory having an external thread on an outer periphery to a tip of a lens barrel. A plurality of holders arranged at intervals in the circumferential direction of the lens barrel, and at a position where each of the holders faces inward in the radial direction of the lens barrel, the holder can be engaged with the external thread of the accessory and engages with the external thread of the accessory. An engagement portion for attaching the accessory to the lens barrel coaxially with the lens barrel, and at least one of the plurality of holders is engaged and disengaged by the engagement portion of each holder and the male screw of the accessory. An engaging state in which the engaging portion of the holding member, which is arranged to be swingable, is engaged with a male screw of an accessory. A disengaged state in which the engaging portion is separated from the male screw. Wherein the rocking means for rocking is provided. Further, the present invention is characterized in that the plurality of holders are all arranged to be swingable.
Further, the present invention is characterized in that the plurality of holders are arranged in a cutout formed at the tip of the lens barrel. Further, the present invention is characterized in that a guide surface for guiding a male screw of an accessory into the lens barrel is formed on an inner periphery of a tip part of the lens barrel. Further, according to the present invention, at the tip of the lens barrel,
An operation ring is provided so as to be movable in the axial direction of the lens barrel between the forward limit position and the backward limit position, and the inner surface of the operation ring and the outer surface of the holding member are engaged with the operation ring positioned at the forward limit position. The engagement state is formed, and in a state where the operation ring is located at the retreat limit position, the engagement between the inner surface of the operation ring and the outer surface of the holder is released and the holder is moved outward in the radial direction of the lens barrel. The disengaged state is formed when the holding member is swung outward in the radial direction of the lens barrel, and an operating ring spring for urging the operating ring toward the forward limit position is provided. A spring for a holder for urging the body outward in the radial direction of the lens barrel is provided, and the swinging means includes an operating ring, a spring for the operating ring, and a spring for the holder. Further, the present invention is characterized in that the engaging portion is formed by a tooth portion that can be engaged with a male screw of an accessory. Further, the present invention is characterized in that the accessory is a filter including a filter plate and a filter frame holding the filter plate.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which an accessory is a filter will be described below with reference to the drawings. First,
The filter will be described with reference to FIG. As shown in the sectional side view in the left half of FIG. 5, the filter 12 includes an annular filter frame 14 and a filter glass 16 (which may be made of plastic) fixed inside the filter frame 14. The filter glass 16 is fixed inside the filter frame 14 by a flange 1402 of the filter frame 14 and a filter holder 18 screwed to the inside of the filter frame 14. The outer periphery of the filter frame 14 has an outer peripheral surface 1404 and an outer peripheral surface 14
And a male screw 1406 formed with an outer diameter smaller than 04. The filter 12 is attached to the lens barrel by screwing the male screw 1406 into a lens barrel of a conventional camera.

Next, the structure of the camera on which the filter 12 is mounted on the lens barrel will be described. As shown in FIG. 3, a photographing lens 24 is fixed to a front end of a lens barrel 22 of a camera by a lens holder 26, and a filter mounting structure 32 of the present embodiment is attached to a front end of the lens barrel 22. , A torsion spring 36, an operating ring 38, a coil spring 40, and the like. More specifically, the inner circumference of the distal end opening of the lens barrel 22 has an inner diameter that is large enough to receive the male screw 1406 and a depth that is larger than the length of the male screw 1406.
02 (corresponding to the guide surface in the claims) is formed, and a female screw 2204 into which the male screw of the lens retainer 26 is screwed into the inner part of the lens barrel 22 following the inner peripheral surface 2202 is smaller than the inner peripheral surface. A step 2206 for accommodating a lens press and a step 2208 with which the outer periphery of the taking lens 24 abuts are formed in the inner part of the female screw 2204. A small-diameter portion 22 for accommodating the operation ring 38 movably in the axial direction of the lens barrel 22 is provided on the outer periphery of the tip of the lens barrel 22.
12 and a groove 2214 are formed.

[0007] As shown in FIG. 1, at the front end of the lens barrel 22 having such a structure, three positions are provided at equal intervals in the circumferential direction.
Notch 222 that is open forward and penetrates from the outer periphery to the inner periphery
2 are respectively formed, and the holder 3
4 are provided respectively. The holding body 34 has a width extending along the circumferential direction of the tip of the lens barrel 22 and a length extending along the axial direction of the lens barrel 22, and extends along the width direction of the holding body 34. The cross section has a substantially arc shape having a radius substantially equal to the tip of the lens barrel 22. As shown in FIG. 3 and FIG. 4, the base end of each holding body 34 is
And the torsion spring 36
And biases the distal end of the holding body 34 so as to be displaced radially outward of the lens barrel 22. An engaging portion 3402 that can engage with the external thread 1406 of the filter 12 is provided at a portion facing the radially inward of the lens barrel 22 at the tip of the holding body 34.
Are formed. In the present embodiment, the engagement portion 34
02 is formed with a tooth portion that can be engaged with the male screw 1406,
More specifically, the teeth have a shape in which a female screw that is screwed into the male screw 1406 is cut off by a predetermined length in the circumferential direction.

The operating ring 38 is inserted over the small-diameter portion 2212 and the groove 2214 at the front end of the lens barrel 22 and is disposed so as to be movable in the axial direction of the lens barrel 22. Irregularities 3802 are formed on the outer periphery of the leading end of the operation ring 38 so that the operation can be easily performed, and an engaging surface 3804 is formed on the inner periphery of the leading end. As shown in FIG. 3, the engagement surface 3804 is engaged with the small diameter portion 2212 of the lens barrel 22 and can be engaged with the outer surface 3404 of the holder 34. A cylindrical guide surface 3806 that engages with the inner surface of the outer peripheral wall 2216 of the groove 2214 is formed on the outer periphery of the rear portion of the operation ring 38. The coil spring 40 is inserted into the groove 2214 on the radial inside of the guide surface 3806, one end of the coil spring 40 abuts on the inner part of the groove 2214 and the other end thereof contacts a part of the operation ring 38. 22 forward. The forward limit position of the operation ring 38 is determined by the operation ring 38
Is determined by contacting the step of the distal end of the guide ring 3 with the step of the distal end of the outer surface 3404 of the holding body 34.
Is determined by contacting the tip of the Since the coil spring 40 is provided, the operation ring 38 is provided.
Is always at the forward limit position, and in order to reach the retreat limit position, the photographer touches the outer periphery of the leading end of the operation ring 38 on which the unevenness 3802 is formed, and resists the urging force of the coil spring 40. It is done by retreating.

Then, as shown in FIGS. 1 and 3, when the operating ring 38 is located near the forward limit position, the engaging surface 3804 of the operating ring 38 is engaged with the outer surface 3404 of the holder 34. The two holders 34 and the tip of the lens barrel 22 are configured as if they were continuous and integral. Also,
As shown in FIGS. 2 and 5, in a state where the operation ring 38 is located near the retreat limit position, the front end of the engagement surface 3804 of the operation ring 38 is engaged with the rear end of the outer surface 3404 of the holder 34. As a result, the three holders 34 can swing outward, and the torsion spring 36 swings the engaging portion 3402 so as to be displaced outward in the radial direction of the lens barrel 22.
Is opened at the front end of. Further, the operation ring 38
Is held in the vicinity of the retreat limit position, the holding body 34 is opened, so that the filter 12 can be attached to and detached from the lens barrel 22. That is, the male screw 1406 of the filter 12 is inserted inside the inner peripheral surface 2202 at the distal end of the lens barrel 22, and the step at the rear end of the outer peripheral surface 1404 can be brought into contact with the distal end surface of the lens barrel 22, From this state, the filter 12 can be separated from the tip of the lens barrel 22.

As described above, the operating ring 38 is set at the retreat limit position, and the male screw 14 of the filter 12 is attached to the front end of the lens barrel 22.
When the finger is released from the operation ring 38 with the 06 inserted, the operation ring 38 moves forward by the urging force of the coil spring 40 to reach the forward limit position. At this time, as the operating ring 38 advances, the engaging surface 3404 of the operating ring 38
804 are engaged, and the three holding bodies 34 are closed from the open state. Eventually, when the operation ring 38 reaches the vicinity of the forward limit position, as shown in FIG.
Meshes with the external thread 1406 of the filter 12, and the operation ring 38
Is biased toward the forward limit position by the coil spring 40 and is held at that position, so that the meshing state between the engaging portion 3402 of the holding body 34 and the male screw 1406 of the filter 12 is maintained, whereby the filter 12 is The lens barrel 22 is attached coaxially to the tip of the lens barrel 22. In the present embodiment, a swing means for swinging the holding body 34 by the operation ring 38, the coil spring 40, and the torsion spring 36 is configured.

In the present embodiment, when the operation ring 38 is set to the retreat limit position, the male screw 1406 of the filter 12 is inserted into the distal end of the lens barrel 22, and the finger is released from the operation ring 38, the holding member 34
Is closed, the engaging portion 3402 of the holder 34 meshes with the male screw 1406 of the filter 12, and the filter 12 is mounted on the distal end of the lens barrel 22. When the filter 12 is to be removed, when the operation ring 38 is set at the retreat limit position, the holder 34 is opened and the engaging portion 3402 of the holder 34 is separated from the male screw 1406 of the filter 12.
Can be separated from the tip. Therefore, according to the present embodiment, the filter 12 can be attached and detached by a simple operation of moving the operation ring 38 along the axial direction of the lens barrel 22, and the attachment and detachment of the filter 12 can be performed easily and quickly. Becomes In addition, the simple structure in which three holding bodies 34 are disposed at the front end of the lens barrel 22 makes it possible to manufacture at low cost. In addition, since the filter 12 is attached and detached by using the male screw 1406 of the conventionally marketed filter 12, the filter 12 can be applied to all commercially available filters, and there is no problem that the types of filters that can be used are limited. Also,
Since the inner peripheral surface 2202 of a size into which the male screw 1406 is inserted is formed on the inner periphery of the distal end opening of the lens barrel 22, the male screw 1406 of the filter 12 is guided by the inner peripheral surface 2202, and the filter 12 is inserted smoothly. Is made.

The number of the holders 34 is not limited to the number in the embodiment, but is arbitrary and at least two. Further, in the embodiment, the case where all the holders 34 are arranged so as to be swingable is described. However, it is not necessary to arrange all the holders 34 so as to be swingable, as long as the filter 12 can be inserted and removed. Therefore, when two or three holding bodies 34 are used, one holding body 34 may be provided so as to be swingable. Further, in the embodiment, the case where the swinging means is constituted by the operation ring 38, the coil spring 40, and the torsion spring 36 has been described.
It is optional, such as using a link mechanism. Further, the present invention is applicable to various accessories other than filters, such as an adapter such as a reverse adapter, in addition to a hood, a teleconverter, and a wide converter attached to the tip of a lens barrel such as a camera or an interchangeable lens. is there.

[0013]

As is clear from the above description, the present invention
An accessory mounting structure for detachably attaching an accessory having an external thread to an end of the lens barrel, the accessory mounting structure including a plurality of holding bodies disposed at intervals in a circumferential direction of the lens barrel at the tip of the lens barrel, At a location where each of the holders faces inward in the radial direction of the lens barrel, an engaging portion that can be engaged with the external thread of the accessory and engages with the external thread of the accessory to attach the accessory to the lens barrel coaxially with the lens barrel. And at least one of the plurality of holding bodies is disposed so as to be swingable in a radial direction of the lens barrel so that an engaging portion of each holding body and an external thread of an accessory can be disengaged. In the lens barrel, the engagement portion of the swingably disposed holder is swung into an engagement state in which the engagement portion is engaged with a male screw of an accessory, and the engagement portion is swung into a disengaged state separated from the male screw. The structure provided with the swing means was provided. Therefore, the attachment and detachment of the accessory can be easily performed with a simple and inexpensive configuration, and all the conventional commercially available screw-in accessories can be used.

[Brief description of the drawings]

FIG. 1 is a perspective view of a front end of a lens barrel of a camera in which a holding body is provided.

FIG. 2 is a perspective view of a front end portion of a lens barrel when a filter is attached by opening a holding body.

FIG. 3 is a sectional side view of a lens barrel.

FIG. 4 is a view of the holding body viewed from the inside of a lens barrel.

FIG. 5 is a sectional side view of the lens barrel when the holder is opened and a filter is attached.

FIG. 6 is a sectional side view of the lens barrel in a state where a filter is attached by a holder.

[Explanation of symbols]

 12 filter 22 lens barrel 34 holder 36 torsion spring 38 operating ring 40 coil spring

Claims (7)

[Claims] 1. An accessory mounting structure for detachably mounting an accessory having an external thread on an outer periphery to a tip of a lens barrel, the accessory mounting structure comprising: a plurality of accessories arranged at the tip of the lens barrel at intervals in a circumferential direction of the lens barrel. A holder is provided, and at a position where each of the holders faces inward in the radial direction of the lens barrel, the accessory can be engaged with the male screw of the accessory and engages with the male screw of the accessory to coaxially mount the accessory with the lens barrel. At least one of the plurality of holders is swingable in the radial direction of the lens barrel so that the engagement part of each holder and the external thread of the accessory can be disengaged. An engagement state in which the engagement portion of the swingably disposed holder is engaged with an external thread of an accessory, and an engagement release state in which the engagement portion is separated from the external thread. And a swing means for swinging is provided. Accessory attachment structure for the butterflies. 2. The accessory mounting structure according to claim 1, wherein the plurality of holders are all arranged to be swingable. 3. The accessory mounting structure according to claim 1, wherein the plurality of holders are disposed in a notch formed at a front end of a lens barrel. 4. A guide surface according to claim 1, wherein a guide surface for guiding a male screw of an accessory into the lens barrel is formed on an inner periphery of a tip portion of the lens barrel. Accessory mounting structure. 5. An operating ring is provided at a front end of the lens barrel so as to be movable in an axial direction of the lens barrel between a forward limit position and a backward limit position, and the operating ring is positioned at the forward limit position. The engagement between the inner surface of the operation ring and the outer surface of the holder is performed with the engagement state being formed by the engagement of the inner surface of the operation ring and the outer surface of the holder. Is released, the holding body can swing outward in the radial direction of the lens barrel, and the holding body swings outward in the radial direction of the lens barrel, so that the disengaged state is formed. An operating ring spring for biasing the holding member in a direction is provided, and a holding member spring for biasing the holding member outward in the radial direction of the lens barrel is provided. 5. The body according to claim 2, wherein the body spring is formed. Accessory mounting structure. 6. The accessory mounting structure according to claim 1, wherein the engaging portion is formed by a tooth portion that can be engaged with a male screw of the accessory. 7. The accessory mounting structure according to claim 1, wherein the accessory is a filter including a filter plate and a filter frame holding the filter plate.