JPH0655141U - Lens accessory attachment / detachment mechanism - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] It can be attached and detached by using the bayonet mechanism, and it is possible to reliably notify the user of the mounting completion state, and the accessory is accidentally released and the accessory falls off. Provided is a lens accessory attaching / detaching mechanism that does not occur. A cylindrical portion at the front end of the lens barrel has at least a pair of bayonet claws 16 projectingly formed on its outer periphery, a holding groove forming wall surface forming a holding groove 18 between the bayonet claws, and at least a pair of The accessory includes a notch and at least a pair of locking claw supports. The tubular portion of the accessory enters the at least a pair of notches in the tip of the lens barrel and rotates into the holding groove to rotate the bayonet claw. At least a pair of elastic fixing claws 38 elastically engaged with the back surface of the pair, and in a state where the elastic fixing claws are elastically engaged with the back surface of the bayonet claw, elastically engage the at least one pair of locking claw support portions from the radial direction. At least one pair of elastic legs 33 are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an attachment / detachment mechanism for attaching / detaching an accessory such as a lens hood to a tip portion of a lens barrel.

[0002]

[Prior art and its problems]

 Some lens barrels allow accessories such as a lens hood, a gelatin filter holder, and a lens cap to prevent harmful rays other than the angle of view of the lens to be attached to the tip of the lens barrel. The conventional means for attaching and detaching accessories such as a lens hood to the tip of the lens barrel is (1) a screw-in type in which the rear end of the accessory is screwed into the tip of the lens barrel, and (2) the tip of the lens barrel. (3) A method of covering the outer periphery with the rear end of the accessory, (3) A method of forming a claw that is elastically movable in the radial direction on the accessory side and dropping the claw into the groove formed on the lens barrel side, (4) Bayonet Formula, etc. are mentioned. Regarding (1) above, it is difficult to quickly attach and detach accessories. In (2) above, holding the accessory at the tip of the lens barrel is unstable. In the above (3), since a member such as a spring member or a locking member is used, the number of parts is increased. Regarding (4) above, as in (3), the number of parts is large, and if there is no locking mechanism, the user will not be able to feel the complete mounting state because there is no click feeling when the mounting is completed.

[0003]

[The purpose of the device]

 The present invention has been made in view of the above-mentioned conventional problems, and is an attachment / detachment mechanism that allows an accessory such as a lens hood to be attached / detached to / from the distal end of the lens barrel by using a bayonet mechanism. To provide a lens accessory attachment / detachment mechanism that can reliably notify the attachment completion state, does not accidentally release the attachment state and does not drop the accessory, and that is configured with an extremely small number of parts. To aim.

[0004]

SUMMARY OF THE INVENTION The present invention is a mechanism for attaching / detaching a tubular portion of an accessory to / from a tubular portion at the tip of a lens barrel, wherein the tubular portion at the tip of the lens barrel is formed to project on the outer periphery thereof. At least one pair of bayonet claws, a retaining groove forming wall forming a retaining groove between the bayonet claws, at least a pair of notches formed between the bayonet claws, and at least a pair of the above bayonet. At least a pair of locking claw support portions formed on the rear side of the claws are provided, and the tubular portion of the accessory is inserted into at least a pair of notches in the distal end portion of the lens barrel to rotate into the holding groove. At least one pair of elastic fixing claws that move and elastically engage the back surface of the bayonet claw, and the at least one pair of locking claw support portions in a state where the elastic fixing claw elastically engages the back surface of the bayonet claw. Diameter And at least a pair of elastic legs that are elastically engaged in the direction.

[0005]

【Example】

 The present invention will be described below with reference to illustrated embodiments. 1 to 3 show a lens barrel 10 to which an attaching / detaching mechanism according to the present invention is applied, and FIGS. 4 and 5 show a lens hood 30 which can be attached to and detached from the tip of the lens barrel 10. ing. The lens barrel 10 is a lens barrel of an interchangeable lens used in, for example, a single-lens reflex camera, and includes a taking lens L having an optical axis X in the front inside (on the left side in FIG. 2) of the lens barrel.

The outer ring 11 forming the exterior of the lens barrel 10 is made of a rigid synthetic resin material or a metal material, and has a tubular portion 12 integrally formed at its front end. The cylindrical portion 12 has an outer peripheral surface 13 parallel to the optical axis X on its outer periphery, and an internal thread portion 9 for mounting an accessory such as a screw-type filter on its inner periphery.

The outer ring 11 is integrally provided with an outer flange portion 14 which is located at the rear of the tubular portion 12 and which is formed to project radially outward along the circumferential direction. The outer flange portion 14 has a wall surface (holding groove forming wall surface) 15 orthogonal to the outer peripheral surface 13 at the front portion thereof, and has an outer peripheral surface 14a parallel to the X axis on the outer periphery thereof. .

The tubular portion 12 is integrally provided with a pair of bayonet claws 16 which are formed at a predetermined position on the outer peripheral surface 13 so as to project radially outward and have a predetermined length in the circumferential direction. The bayonet claw 16 has a wall surface 17 parallel to the wall surface 15 at its rear portion. A holding groove portion (holding groove) 18 is formed between the wall surface 17 and the wall surface 15. Inside the holding groove portion 18, an elastic fixing claw portion 38 and an elastic leg portion 33 formed on a lens hood 30 described later slide. The holding groove portion 18 has a bottom surface portion 18a extending in the circumferential direction, and the length from the X axis to the bottom surface portion 18a is set to be longer than the length from the X axis to the outer peripheral surface 13 by a predetermined amount. There is. The bayonet claw 16 is located at the rear of both ends in the circumferential direction, and the step portion caused by the difference in length from the X axis of the bottom surface portion 18a and the outer peripheral surface 13 is a step portion 16a, a step portion (locking claw support portion) 16b. Is formed as. Further, the tubular portion 12 is formed as a notch (notch) 19 in a portion along the circumferential direction where the bayonet claw 16 is not formed on the outer peripheral surface 13 thereof. The clogged cylindrical portion 12 has a pair of notches 19 between the pair of bayonet claws 16 in the circumferential direction.

On the other hand, the lens hood 30 having a cylindrical shape is made of an elastically deformable synthetic resin material, and has an inner flange portion that is formed at a rear end (right side in FIG. 5) of the lens hood 30 so as to project radially inward. 31 is provided. The inner flange portion 31 has an inner peripheral surface 31a which is parallel to the central axis C of the lens hood 30 and is formed so as to be capable of fitting with the outer peripheral surface 14a of the outer flange portion 14 of the lens barrel 10. ing. The central axis C of the lens hood 30 coincides with the optical axis X of the lens barrel 10 when the lens hood 30 is attached to the lens barrel 10.

As shown in FIG. 4, the inner flange portion 31 has a pair of inner peripheral engagement portions A and inner peripheral engagement portions B that are rotationally symmetrical with respect to the central axis C. The parts A and B each include an elastic leg part 33, an elastic fixing claw part 38 and a rotation restricting part 43 which are adjacent to each other in the circumferential direction. The elastic leg portion 33, the elastic fixing claw portion 38, and the rotation restricting portion 43 are formed so that their rear surfaces in the central axis C direction are located on the same plane orthogonal to the central axis C.

The elastic leg portion 33 includes a fixed end portion 33a formed to project from a bottom surface 35a of a cutout portion 35 formed in the inner flange 31, and an arm extending from the fixed end portion 33a along the circumferential direction. It has a portion 33b and a free end portion 33d having an engaging projection portion 33c formed so as to project radially inward from the arm portion 33b. The length of the cutout portion 35 in the circumferential direction is set to be longer than the length of the elastic leg portion 33 in the circumferential direction. With this configuration, the elastic leg portion 33 is elastically deformable toward the outer side in the radial direction where the free end portion 33d enters the inside of the cutout portion 35 with the fixed end portion 33a as the rotation base portion. In the free state of the elastic leg portion 33, the engagement projection portion 33c has a length from the tip facing inward to the center line C slightly smaller than the length from the outer peripheral surface 13 of the lens barrel 10 to the optical axis X. It is set to be long and shorter than the length from the bottom surface portion 18a to the optical axis X. The thickness of the elastic leg portion 33 in the central axis C direction is set to be slightly smaller than the width of the holding groove portion 18 of the lens barrel 10 in the optical axis X direction.

The elastic fixing claw portion 38 is formed so as to project radially inward from the inner peripheral surface 31a. The length from the end surface protruding inward in the radial direction of the elastic fixing claw portion 38 to the central axis C is formed to be slightly longer than the distance from the bottom surface portion 18a of the lens barrel 10 to the optical axis X. The elastic fixing claw portion 38 also has a uniform thickness T as shown in FIG. 5, and this thickness T is slightly shorter than the width of the holding groove portion 18 of the lens barrel 10 in the optical axis X direction. It is set. Further, the elastic fixing claw portion 38 is set such that the entire width W in the central axis C direction in the free state thereof is slightly larger than the width of the holding groove portion 18 of the lens barrel 10.

The rotation restricting portion 43 restricts a rotation range of the lens hood 30 with respect to the lens barrel 10 when the lens hood 30 is mounted on the lens barrel 10. The rotation restricting portion 43 is formed so that the length protruding inward in the radial direction is substantially the same as the length of the elastic fixing claw portion 38, and the thickness in the central axis C direction is the holding of the lens barrel 10. The groove 18 is set wider toward the front than the thickness in the optical axis X direction.

6 to 12 show how the lens hood 30 is attached to the lens barrel 10 when they are attached to each other. 6 and 7 show the initial state (the initial mounting state) in which the lens hood 30 is fitted to the tip of the lens barrel 10. When the lens hood 30 is attached to the lens barrel 10, first, as shown in the same figure, the elastic leg portions 33 of the lens hood 30 and the elastic fixing portions are fixed to the pair of notches 19 of the lens barrel 10. The inner flange 31 of the lens hood 30 is fitted to the front end of the lens barrel 10 so as to insert the pair of inner peripheral engaging portions A and B, each of which includes the claw portion 38 and the rotation restricting portion 43. At this time, the inner peripheral surface 31a of the lens hood 30 is fitted to the outer peripheral surface 14a of the lens barrel 10, and the elastic leg portion 33, the elastic fixing claw portion 38, and the rotation restricting portion 43 are respectively arranged in the central axis C direction. The rear surface is brought into contact with the wall surface 15 of the lens barrel 10.

FIGS. 8 and 9 show a state in which the lens hood 30 has been rotated by a predetermined amount in the clockwise direction with respect to the lens barrel 10 (right rotation in the same figure) from the initial mounting state shown in FIGS. 6 and 7. (In the middle of mounting). In this state, the engaging protrusion 33c of the elastic leg portion 33 rides over the step portion 16a located at one end of the bayonet claw 16 and enters the holding groove portion 18, and the elastic leg portion 33 elastically moves outward in the radial direction. Since it is deformed, the bottom surface portion 18a is pressed inward in the radial direction with a constant force.

FIG. 10 to FIG. 12 show a state in which the mounting state is further rotated clockwise (mounting completed state). In this state, the engaging projection portion 33c of the elastic leg portion 33 rotates in the holding groove portion 18 together with the leg portion 33b while pressing the bottom surface portion 18a, and a step portion located behind one end of the bayonet claw 16 is formed. It returns to the inside in the radial direction at 16b and then engages with the stepped portion 16b. When the engagement protrusion 33c engages with the step 16b, a click feeling is generated, so that the operator who operates the lens hood 30 can obtain the feel of the attachment completed state. At the same time that the free end portion 33c engages with the step portion 16b, the rotation restricting portion 43 comes into contact with the other end of the bayonet claw 16 on the side having the step portion 16a. In other words, the lens hood 30 has a structure in which when the free end portion 33a of the elastic leg portion 33 is rotated to a position where the free end portion 33a engages with the step portion 16b, the lens hood 30 does not rotate further. The relationship between the free end portion 33c, the step portion 16b, the rotation restricting portion 43, and the step portion 16a is shown in FIG. In this figure, the rotation restricting portion 43 does not actually appear in the cross section taken along the line XI-XI, but is shown in phantom to show the above relationship in the figure.

In the figure, the elastic fixing claw portion 38 adjacent to the elastic leg portion 33 is positioned in the holding groove portion 18 after entering the holding groove portion 18 subsequent to the elastic leg portion 33. In the free state, the elastic fixing claw portion 38 has a width W in the optical axis X (center axis C) direction set to be wider than the width of the holding groove portion 18 as described above. It is bent in the direction of the axis X and elastically deforms. Therefore, when the lens hood 30 is completely attached, the elastic fixing claw portion 38 presses the wall surface 15 and the wall surface 17 located in the front and rear in the holding groove portion 18 in the front-rear direction, respectively, whereby the optical axis X of the lens hood 30. Keep the position in the direction constant.

To remove the lens hood 30 from the mounted state, the lens hood 30 may be rotated in a direction (counterclockwise) opposite to the direction in which the lens hood 30 is rotated. When the lens hood 30 is detached, the elastic fixing claw portion 38 resists the force pressing the wall surfaces 15 and 17, and the engagement protrusion 33c of the elastic leg portion 33 engages with the step portion 16b. It is understood that the lens hood 30 does not come off accidentally because the lens hood 30 has to be released.

In the present embodiment, the lens barrel and the lens hood each have a pair of bayonet claws and inner peripheral engaging portions that engage with the bayonet claws. However, a plurality of bayonet claws of two or more are provided. Alternatively, the inner peripheral engagement portion may be formed in each.

Further, according to the attachment / detachment mechanism of the present invention, the rotation angle of the accessory with respect to the fixed position of the lens barrel is reliably determined. Therefore, the attachment / detachment mechanism of the present invention allows an accessory such as a deformed lens hood to be attached to the lens barrel. Effective for mounting.

In the present embodiment, the accessory to be attached to the distal end portion of the lens barrel has been described with respect to the lens hood, but the present invention is not limited thereto. The mounting mechanism is not limited to the lens hood, and may be any mounting mechanism that allows the tip of the lens barrel to be attached to and detached from other barrel-shaped or ring-shaped accessories. Further, it goes without saying that the lens barrel is not limited to a lens barrel for photographing, and may be various lens barrels such as a telescope.

[0022]

[Effect of device]

 As described above, according to the present invention, at least a pair of elastic fixing claws that respectively enter into at least a pair of notches in the front end portion of the lens barrel, rotate into the holding groove, and elastically engage with the back surface of the bayonet claw. Since the elastic fixing claw is elastically engaged with the back surface of the bayonet claw, at least a pair of elastic legs that are elastically engaged in the locking claw support portion in the radial direction are provided. It is possible to provide an accessory attachment / detachment mechanism for a lens that can reliably notify the attachment completion state and prevent the accessory from falling off accidentally due to the attachment state being released.

Furthermore, since the accessory can be integrally molded with a synthetic resin material, the number of parts can be reduced and the cost performance is excellent.

[Brief description of drawings]

FIG. 1 is a view of a lens barrel according to the present invention as viewed from the front of an optical axis.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a view of the lens hood according to the present invention as viewed from the front of the central axis.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a view showing the initial mounting state of the lens hood and the lens barrel as viewed from the front of the optical axis.

FIG. 7 is a sectional view taken along line IIV-IIV in FIG.

FIG. 8 is a diagram showing a state where the lens hood and the lens barrel are being attached, as viewed from the front of the optical axis.

FIG. 9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is a diagram showing a state where the lens hood and the lens barrel are completely attached, as viewed from the front of the optical axis.

FIG. 11 is a sectional view taken along line XI-XI in FIG.

12 is a sectional view taken along line XII-XII in FIG.

[Explanation of symbols]

 10 Lens barrel 11 Outer ring 12 Cylindrical part 13 Outer peripheral surface 14 Outer flange part 14a Outer peripheral surface 15 Wall surface (holding groove forming wall surface) 16 Bayonet claw 16a Step part 16b Step part (locking claw support part) 17 Wall surface 18 Holding Groove portion (holding groove) 18a Bottom surface portion 19 Notch portion (notch) 30 Lens hood 31 Inner flange portion 31a Inner peripheral surface 33 Elastic leg portion 33a Fixed end portion 33b Arm portion 33c Engaging protrusion portion 33d Free end portion 35 Notch portion 38 Elastic fixed claw portion 43 Rotation restriction portion A, B Inner peripheral engagement portion L Lens C Central axis X Optical axis

Claims (3)

[Scope of utility model registration request] 1. A mechanism for attaching / detaching a tubular portion of an accessory to / from a tubular portion at the tip of a lens barrel, wherein the tubular portion at the tip of the lens barrel has at least one pair formed to project on the outer periphery thereof. A bayonet claw; a holding groove forming wall forming a holding groove between the bayonet claw; at least a pair of notches formed between the bayonet claws; formed on the rear side of the at least a pair of bayonet claws And a pair of locking claw support portions; and the tubular portion of the accessory enters into at least a pair of notches in the distal end portion of the lens barrel and rotates into the holding groove to move the bayonet claw. At least a pair of elastic fixing claws elastically engaged with the back surface; and in a state where the elastic fixing claws are elastically engaged with the back surface of the bayonet claw, elastically applied to the at least one pair of locking claw support portions in the radial direction. Lens, characterized in that it comprises an accessory detachable mechanism, at least a pair of resilient legs and the focus. 2. The lens accessory attaching / detaching mechanism according to claim 1, wherein the locking claw support portion is constituted by one end of a bayonet claw. 3. The lens attachment / detachment mechanism according to claim 1, wherein the tubular portion of the accessory is made of a synthetic resin material.