JPH0552809U - Silent mechanism for lens barrel - Google Patents

Abstract

(57) [Abstract] [Purpose] In a lens barrel having a switch ring for performing some kind of switching by linearly moving in the direction of the optical axis, a sound deadening mechanism capable of reducing noise when the switch ring is moved to both moving ends. To get. A lens barrel having a switch ring that can be moved forward and backward and rotated in the direction of the optical axis, and a support ring that supports the switch ring, wherein the straight forward and backward movement is made on the inner peripheral surface of the switch ring. A circumferential groove having a width corresponding to the operation distance is formed, a stopper member located in the circumferential groove is fixed to the support ring, and the stopper member is brought into contact with inner walls before and after the circumferential groove. A lens silencing mechanism equipped with an elastic member.

Description

[Detailed description of the device]

[0001]

【Technical field】

 The present invention relates to a lens barrel having a switch ring that can be moved forward and backward in the optical axis direction and rotated, and more particularly to a sound deadening mechanism for the lens barrel.

[0002]

[Prior art and its problems]

 For example, in AF single-lens reflex cameras, conventionally, switching between manual focus (MF) and auto focus (AF) has been performed on the body side. In an AF single-lens reflex camera, an AF axis is provided on the camera body, and a driven AF axis driven by the AF axis is provided on the interchangeable lens side. The state in which both AF axes are connected is the AF state, and the rotation of the AF axes causes the focus lens group to move in the optical axis direction, and at the same time, the focus ring on the lens side also rotates. To enter the MF state, the body-side AF axis and lens-side driven AF axis are disconnected, and the lens-side focus ring is manually rotated. In this conventional lens barrel, the focus ring on the lens side also rotates during AF. For this reason, the focus ring itself is made smaller (narrower) and placed at the tip of the lens barrel so as not to get in the way during AF. On the contrary, if it is at the tip of the lens barrel, it is difficult to operate during MF. Further, the switch for switching between AF and MF is provided on the body side, and there is a problem that it is difficult to operate depending on the camera position.

Based on such awareness of problems, the present applicant has provided an AF-MF switching ring (switch ring) capable of a straight forward / backward operation and a rotational operation in the optical axis direction, and this AF-MF switching ring is At the MF position in the optical axis direction, the manual focusing is performed by rotating the AF-MF switching ring, and at the AF position, the AF operation is performed without rotating the AF-MF switching ring. We have separately applied for a patent for a lens barrel designed to be used.

However, in this lens barrel, when the AF-MF switching ring is moved back and forth in the optical axis direction, a part of the switching ring collides with a stopper member that limits the moving range of the AF-MF switching ring, and metallic noise or the like occurs. Occasionally, a strange noise was generated.

The same problem also occurs in a power zoom lens barrel that switches between manual zooming and power zooming, for example, by straight movement of a switch ring in the optical axis direction. This power zoom lens barrel was proposed by the applicant of the present application in Japanese Patent Application No. 2-28902 and the like. When the zoom switch ring is moved to the manual position, the zoom switch ring rotates forward and backward, Manual zooming is possible. When the zoom switch ring is moved to the auto position, forward and reverse power zooming can be performed by forward and reverse rotation of the zoom switch ring.

[0006]

[The purpose of the device]

 Based on this awareness, the present invention provides a lens barrel having a switch ring for performing some kind of switching by linear movement in the optical axis direction, and a sound generated when the switch ring is moved to both moving ends. The purpose is to obtain a muffling mechanism that can reduce the noise.

[0007]

[Outline of the device]

 The present invention relates to a lens barrel including a switch ring that can be moved forward and backward in the optical axis direction and a rotary operation, and a support ring that supports the switch ring. A circumferential groove having a width corresponding to the advancing / retreating operation distance is formed, and a stopper member located in the circumferential groove is fixed to the support ring, and the stopper member is brought into contact with the inner walls before and after the circumferential groove. It is characterized in that an elastic member is provided. According to this sound deadening mechanism, the switch ring collides with the elastic member of the stopper member at the front and rear moving ends thereof, so that a sound deadening effect can be obtained.

Then, a pair of annular grooves are formed on the inner surface of the switch ring corresponding to the straight forward / backward operation distance, and a click ball which is selectively inserted into the pair of annular grooves is formed on the support ring. Further, the circumferential groove and the elastic member of the stopper member are arranged so that, when the click ball is properly fitted in the pair of annular grooves, the elastic members of the circumferential groove and the stopper member are not in contact with the inner walls before and after the circumferential groove. By setting the position and the shape, the elastic member of the stopper member does not act as a rotation resistance when the switch ring is rotated.

[0009]

【Example】

 The present invention will be described below with reference to the illustrated embodiments. In this embodiment, the present invention is applied to a lens barrel having an AF-MF switching ring. First, the overall structure of the lens barrel will be described with reference to FIGS. A focus lens frame 12 supporting a focus lens L1 is fitted on the inner circumference of the fixed ring 10 having a mounting mount 11 for mounting the camera body at the rear end. The fixed ring 10 is actually composed of a combination of a plurality of annular members, but in the figure, it is drawn as one member for convenience. A linear guide groove 13 is formed in the fixed ring 10, and a guide pin 14 fixed to the focus lens frame 12 is fitted in the linear guide groove 13. A focus ring 15 is rotatably fitted to the fixed ring 10 so as to be positioned outside the linear guide groove 13 of the focus lens frame 12. The focus ring 15 is provided with a lead groove 16 into which the guide pin 14 is fitted, so that when the focus ring 15 is rotated, the focus ring 15 follows the inner groove 13, the lead groove 16 and the guide pin 14 for straight advancement. The focus lens frame 12 (L1) moves in the optical axis direction for focusing. The rotation range of the focus ring 15 is regulated by a pair of stopper projections 18 provided on the fixed ring 10 and a stopper projection 19 provided on the focus ring 15. A photographing distance scale 20 is provided on the focus ring 15, and the photographing distance scale 20 is observed through an observation window 21 formed in the fixed ring 10.

An internal gear 24 is formed on the inner periphery of the rear portion of the focus ring 15. On the other hand, on the fixed ring 10, an AF transmission shaft 26 having a pinion 25 that meshes with the internal gear 24 is movably supported in the axial direction (direction parallel to the optical axis). Another pinion 27 is fixed to the rear end portion of the AF transmission shaft 26, and the pinion 27 meshes with the pinion 29 of the driven AF shaft 28. As is well known, the driven AF shaft 28 is coupled to the AF shaft inside the camera body when mounted on a camera body (not shown). The rotation of the driven AF shaft 28 is transmitted to the pinion 25 via the gear train.

An AF-MF switching ring 31 is supported on the fixed ring 10 at an intermediate portion in the longitudinal direction thereof so as to be capable of rectilinear advance / retreat operation in the optical axis direction and rotational operation. A decorative ring 32 is fitted around the outer circumference of the AF-MF switching ring 31. In this embodiment, the state where the AF-MF switching ring 31 is moved to the front moving end (FIG. 1) is the AF position, and the state where it is moved to the rear moving end (FIG. 2) is the MF position. On the inner surface of the AF-MF switching ring 31, annular V grooves 33 and 34 are formed in correspondence with the AF position and the MF position, and the fixed ring 10 has one of the annular V grooves 33 and 34. A click ball 35 that is fitted into one side and a leaf spring 36 that biases the click ball 35 are provided. The AF-MF switching ring 31 is formed with a circumferential groove 39 on its inner surface for restricting the front-back movement range. The fixed ring 10 is located in the circumferential groove 39 and has a circumferential groove. Position regulating pins 40 (pin members) that are in contact with the inner walls of the front and rear of 39 are fixed.

A first clutch mechanism 43 is provided between the AF-MF switching ring 31 and the focus ring 15. The first clutch mechanism 43 allows the focus ring 15 to rotate freely with respect to the AF-MF switching ring 31 when the AF-MF switching ring 31 is at the front AF position, and when the AF-MF switching ring 31 is at the rear MF position. , The AF-MF switching ring 31 and the focus ring 15 are integrated in the rotational direction. On the inner surface of the front portion of the AF-MF switching ring 31, a small diameter portion 44, a taper diameter portion 45 and a large diameter portion 46 are sequentially formed from the front. On the other hand, a radial hole 47 is formed in the focus ring 15, and a clutch pin 48 whose position matches the small diameter portion 44, the tapered diameter portion 45 or the large diameter portion 46 is slidable in this hole 47. It is fitted. The clutch pin 48 has its retaining head 49 restraining its outward projecting end, and is urged to move outward by a leaf spring 50. One end of the leaf spring 50 is fixed to the inner surface of the focus ring 15 by a fixing screw 38. An example of the shape of the clutch pin 48 alone is shown in FIG. The clutch pin 48 is shaped, for example, so that both ends thereof are contact surfaces 51 in order to increase the coefficient of friction with the large diameter portion 46 of the AF-MF switching ring 31.

A second clutch mechanism 53 is provided between the AF-MF switching ring 31 and the AF transmission shaft 26. This second clutch mechanism 53 meshes the pinion 25 of the AF transmission shaft 26 with the internal gear 24 of the focus ring 15 when the AF-MF switching ring 31 is in the front AF position, and the rear MF position. In the case of, the pinion 25 of the AF transmission shaft 26 and the internal gear 24 of the focus ring 15 are disengaged. An annular groove 54 is formed on the inner surface of the AF-MF switching ring 31, and a pin 56 protruding from the clutch plate 55 is fitted in the annular groove 54. As shown in FIG. 5, the clutch plate 55 includes a forked portion 57, and the forked portion 57 is engaged with a flange portion 58 formed on the AF transmission shaft 26.

On the other hand, a clutch plate 60 paired with the clutch plate 55 is fixed to the fixed ring 10. The clutch plate 60 also has a bifurcated portion 61, and the bifurcated portion 61 is engaged with a spring receiving ring 62 slidably fitted on the AF transmission shaft 26. A compression spring 63 is inserted between the spring bearing ring 62 and the flange portion 58 to urge the AF transmission shaft 26 forward, that is, in the direction in which the pinion 25 meshes with the internal gear 24. The forward movement end of the AF transmission shaft 26 is regulated at a position where the flange portion 58 abuts the forked portion 57 of the clutch plate 55.

Further, between the AF-MF switching ring 31 and the fixed ring 10, there is a lock mechanism 65 that locks the AF-MF switching ring 31 when the AF-MF switching ring 31 is moved to the AF position. It is provided. As shown in FIG. 7 to FIG. 9, the lock mechanism 65 includes a plurality of lock grooves 66 on the fixed ring 10 at appropriate angular intervals, while an AF-MF switching ring 31 and an AF-MF switching ring are provided. When 31 is in the AF position, a lock ball 67 fitted into this lock groove 66 and its biasing leaf spring 68 are provided. The AF-MF switching ring 31 is formed adjacent to the lock groove 66 with a smooth arc surface 69 with which the biasing leaf spring 68 contacts when the AF-MF switching ring 31 is in the MF position.

The lens barrel having the above structure operates as follows. As shown in FIG. 1, in the AF state in which the AF-MF switching ring 31 has been moved forward, the first clutch mechanism 43 releases the integrated rotation relationship between the AF-MF switching ring 31 and the focus ring 15, The clutch mechanism 53 engages the pinion 25 of the AF transmission shaft 26 with the internal gear 24 of the focus ring 15, and the lock mechanism 65 locks the AF-MF switching ring 31 to the fixed ring 10. That is, the tip of the clutch pin 48 supported by the focus ring 15 is at the position of the large diameter portion 46 on the inner surface of the AF-MF switching ring 31, and is kept in non-contact with the AF-MF switching ring 31 (see FIG. 3). On the other hand, the pinion 25 of the AF transmission shaft 26 biased forward by the compression spring 63 meshes with the internal gear 24 of the focus ring 15. In this state, when the driven AF shaft 28 is rotated by the AF shaft on the camera body side, the rotation is transmitted to the focus ring 15 and thus AF is performed. At this time, the lock ball 67 is fitted into one of the lock grooves 66 of the fixed ring 10 (FIG. 8). Even if the lock ball 67 is not fitted in the lock groove 66 (FIG. 9), if the small angle AF-MF switching ring 31 is turned to any direction, the state shown in FIG. Therefore, the AF-MF switching ring 31 does not rotate in the AF state, and the usability due to the rotation of the grip portion does not occur.

On the other hand, as shown in FIG. 2, when the AF-MF switching ring 31 is moved rearward to be in the MF state, the first clutch mechanism 43 causes the AF-MF switching ring 31 and the focus ring to move. 15, the second clutch mechanism 53 disengages the pinion 25 of the AF transmission shaft 26 from the internal gear 24 of the focus ring 15, and the lock mechanism 65 locks the AF-MF switching ring 31. Unlock. That is, the contact surface 51 at the tip of the clutch pin 48 supported on the focus ring 15 makes strong frictional contact with the small diameter portion 44 on the inner surface of the AF-MF switching ring 31 to connect the AF-MF switching ring 31 and the focus ring 15. On the other hand, as the AF-MF switching ring 31 moves rearward, the bifurcated portion 57 of the clutch plate 55 pushes the AF transmission shaft 26 backward against the compression spring 63, and the pinion 25. , The engagement of the focus ring 15 with the internal gear 24 is released. Further, the lock ball 67 comes into contact with the smooth circular arc surface 69 of the fixed ring 10 to unlock the AF-MF switching ring 31 (FIG. 7). When the AF-MF switching ring 31 is manually rotated in this state, the rotation is transmitted to the focus ring 15 via the small diameter portion 44, the clutch pin 48 and the hole 47. Therefore, MF is performed. At this time, even if the driven AF shaft 28 is rotated by the AF shaft on the camera body side, the rotation is not transmitted to the focus ring 15. The axial position of the AF-MF switching ring 31 at this time is regulated by the engagement of the annular V groove 33 and the click ball 35.

The gist of the present invention is, for example, the structure of the circumferential groove 39 and the position regulating pin 40 that regulate the front and rear movement range of the AF-MF switching ring 31 in the lens barrel configured as described above. Is. The circumferential groove 39 is formed as an entire circumferential groove as shown in FIG. The width T in the front-rear direction is set to be larger than the distance t between the centers of the annular V groove 33 and the annular V groove 34 by a predetermined amount.

As shown in FIG. 10, four position regulating pins 40 are provided at equal angular intervals in the circumferential groove 39, which is a circumferential groove, in the illustrated embodiment. It is preferable that three or more position regulating pins 40 are provided at equal angular intervals. As shown in exploded view in FIG. 11, each position regulating pin 40 is provided with a semi-circular groove 40a on its peripheral surface, and an elastic member (O-ring) 41 is fitted in the semi-circular groove 40a. Then, the elastic member 41 of the position control pin 40 is configured such that when the click ball 35 is properly fitted into the annular V groove 33 or 34, that is, the spring force of the click ball 35 causes the 35 to be evenly distributed in the annular V groove 33 or 34. At the axial position of the AF-MF switching ring 31 located at, the position is determined so as not to be in contact with the front and rear inner walls of the circumferential groove 39. In FIG. 12 and FIG. 13, inner walls 39a, 39b and elastic members at the front and rear of the circumferential groove 39 and elastic members at the regular positions before and after the AF-MF switching ring 31 in which the click ball 35 is normally fitted in the annular V groove 33 or 34. A clearance x 1 is formed between each of them and 41. Reference numeral 31a is an assembly hole when the position regulating pin 40 is screwed and fixed to the fixed ring 10, and is covered with the decorative ring 32 after the position regulating pin 40 is screwed and fixed.

According to the sound deadening mechanism, when the AF-MF switching ring 31 is moved back and forth, the inner wall 39a or 39b of the circumferential groove 39 collides with the elastic member 41 of the position regulating pin 40. That is, when the AF-MF switching ring 31 is slid back and forth, a certain amount of force is applied, so that the annular V groove 33 or 34 pushes down the click ball 35 while bending the leaf spring 36. That is, the AF-MF switching ring 31 moves beyond the position where the annular V groove 33 or 34 is normally fitted into the click ball 35, and as a result, the elastic member 41 and the inner wall of the circumferential groove 39 are formed. Collide. The impact at the time of this collision is mitigated by the elastic member 41, and the generation of sound is softened. When the external force applied to the AF-MF switching ring 31 is released, the force of the leaf spring 36 moves the AF-MF switching ring 31 to a position where the click ball 35 is evenly fitted into the annular V groove 33 or 34. At this time, the elastic member 41 is not in contact with the inner wall 39a or 39b of the circumferential groove 39 (FIGS. 11 and 12). Therefore, when the AF-MF switching ring 31 is subsequently rotated, the elastic member 41 does not become a resistance.

14 to 16 show a second embodiment. As shown in FIG. 14, the stopper member in this embodiment is a position regulating ring 70 (ring member) that extends over substantially the entire circumference of the fixed ring 10, and the elastic members are fixed in front of and behind the position regulating ring 70. The elastic member 71. The difference between the above embodiment and this embodiment lies in the constitution of the stopper member and the elastic member, and the other constitutions are the same as in the above embodiment.

The position regulating ring 70 made of a metal material having a certain elasticity such as brass has screw insertion holes 70 a formed at a plurality of circumferential positions (for example, four positions as shown in the drawing). It is fixed to the fixed ring 10 so as to be positioned in the circumferential groove 39 by the fixing screw 72 through the screw insertion hole 70a.

Further, the position regulating ring 70 has annular grooves 70b having a half-moon-shaped cross section on the front and rear end faces in the optical axis direction. The elastic member 71 is adhered and fixed to each of the annular grooves 70b with an adhesive or the like.

Before being fixed to the annular groove 70b, the elastic member 71 is a rod-shaped elastic material shown by a broken line 71 'in FIG. 14, and is fixed to the annular groove 70b while being bent along the shape of the annular groove 70b. To be done.

The position regulating ring 70 is fixed as follows. First, the position restricting ring 70 is inserted into the AF-MF switching ring 31 in a reduced diameter state, and when the position restricting ring 70 is inserted to the position of the inner circumferential groove portion 39, the diameter is self-reset so that the position regulating ring 70 is placed inside the inner circumferential groove portion 39. Position in advance. Next, the AF-MF switching ring 31 is fitted and fixed to the fixed ring 10. After that, the position regulating ring 70 is fixed to the fixed ring 10 by the fixing screw 72 inserted through the assembly hole 31a provided in the AF-MF switching ring 31.

17 and 19 show a third embodiment. The position regulating ring 70 in the second embodiment has an annular groove 70b formed in the front and rear thereof, and the rod-shaped elastic member 71 is fixed to the annular groove 70b. 80 (ring member) is flat without grooves or the like in front and rear thereof, and a sheet-like elastic member 81 corresponding to the shape is adhered and fixed to this flat surface. Other configurations are common to those of the second embodiment.

According to the second and third embodiments, since the stopper member having the elastic member is provided over substantially the entire circumference of the fixed ring 10, the effective area for absorbing the impact of the elastic member can be widened. This makes it possible to obtain higher noise reduction and shock absorption.

In the embodiment described above, the present invention is applied to the AF-MF switching ring 31 for switching between AF and MF, but as described above, the present invention is a zoom switch for switching between manual zoom and power zoom. It can also be applied to rings.

[0029]

As described above, according to the sound deadening mechanism for a lens barrel of the present invention, the elastic members of the stopper member provided on the support ring and the inner surfaces of the switch ring on the front and rear sides of the circumferential groove provided on the inner peripheral surface of the switch ring are provided. Since the front and rear moving ends of the switch ring are regulated by the collision with, no abnormal noise such as metallic noise is generated when the switch ring is moved back and forth. In addition, a sound deadening mechanism can be configured on the inner surface of the switch ring, saving space. According to the second aspect, since the circumferential groove and the elastic member do not come into contact with each other when the switch ring is rotated, the rotation resistance of the switch ring does not increase due to the sound deadening mechanism.

[Brief description of drawings]

FIG. 1 is an upper half longitudinal sectional view in an AF state showing an embodiment of a lens barrel having a sound deadening mechanism according to the present invention.

FIG. 2 is an upper half longitudinal sectional view of the same MF state.

FIG. 3 is a cross-sectional view of the clutch in the AF state taken along the line AA of FIG.

FIG. 4 is a cross-sectional view of the clutch in the MF state taken along the line BB in FIG.

5 is a perspective view showing an example of an AF transmission shaft urging mechanism in the lens barrel of FIG.

FIG. 6 is a perspective view of a focus clutch pin.

7 is a cross-sectional view of the main part taken along the line CC of FIG. 2, showing the unlocked state of the AF-MF switching ring locking mechanism.

8 is a cross-sectional view of a main part taken along the line DD of FIG. 1, showing a locked state of the AF-MF switching ring lock mechanism.

9 is a cross-sectional view of a main part taken along line D-D of FIG. 1, showing another state of the AF-MF switching ring lock mechanism in the locked state.

FIG. 10 is a cross-sectional view taken along the line EE of FIGS. 1 and 2.

FIG. 11 is an exploded perspective view of a position regulating pin used in the silencing mechanism of the lens barrel according to the present invention.

FIG. 12 is a sectional view showing an essential part of a silencing mechanism for a lens barrel according to the present invention.

FIG. 13 is a sectional view showing a main part of a silencing mechanism for a lens barrel according to the present invention, in a state different from that of FIG.

FIG. 14 is an exploded perspective view of a position restricting ring and an elastic member according to a second embodiment used in the sound deadening mechanism of the lens barrel according to the present invention.

FIG. 15 is a sectional view taken along line EE of FIGS. 1 and 2 in the second embodiment.

16 is a partial cross-sectional view showing a portion surrounded by a broken line F shown in FIG. 1 in the second embodiment.

FIG. 17 is an exploded perspective view of a position restricting ring and an elastic member according to a third embodiment used in the sound deadening mechanism of the lens barrel according to the present invention.

FIG. 18 is a sectional view taken along the line EE of FIGS. 1 and 2 in the third embodiment.

FIG. 19 is a partial cross-sectional view showing a portion surrounded by a broken line F shown in FIG. 1 in the third embodiment.

[Explanation of symbols]

 10 fixed ring (support ring) 11 mounting mount 12 focus lens frame 13 straight guide groove 14 guide pin 15 focus ring 16 lead groove 18 stopper protrusion 19 stopper protrusion 20 shooting distance scale 21 observation window 24 internal gear 25 pinion 26 AF transmission shaft 27 pinion 28 driven AF shaft 29 pinion 31 AF-MF switching ring (switch ring) 32 decorative ring 33 34 annular V groove 35 click ball 36 leaf spring 38 fixing screw 39 circumferential groove 40 position regulating pin (pin member) 41 elastic member (O-ring) 43 First clutch mechanism 44 Small diameter portion 45 Tapered diameter portion 46 Large diameter portion 47 Hole 48 Clutch pin 49 Locking head 50 Leaf spring 51 Contact surface 53 Second clutch mechanism 54 Annular groove 55 Clutch plate 56 Pin 57 Bifurcated part 58 Flange part 60 Pitch plate 61 crotch 62 the spring receiver ring 70 position restricting ring (ring member) 71 elastic member 80 position restricting ring (ring member) 81 elastic member

Claims (4)

[Scope of utility model registration request] 1. A lens barrel provided with a switch ring that can be moved forward and backward and rotated in the direction of the optical axis, and a support ring that supports the switch ring. A circumferential groove having a width corresponding to the rectilinear advance / retreat operation distance is formed, a stopper member located in the circumferential groove is fixed to the support ring, and the stopper member is provided on inner walls before and after the circumferential groove. A silencing mechanism for a lens barrel, which is provided with an abutting elastic member. 2. The switch ring according to claim 1, wherein a pair of annular grooves are formed on the inner surface of the switch ring corresponding to the straight forward / backward operation distance, and the pair of annular grooves are selectively inserted into the support ring. The click groove is supported, and the circumferential groove and the elastic member of the stopper member are not in contact with the inner walls before and after the circumferential groove when the click ball is properly fitted in the pair of annular grooves. The silencing mechanism of the lens barrel whose position and shape are set. 3. The lens mirror according to claim 1, wherein the stopper member is a pin member provided in the circumferential groove with a space, and the elastic member is an O-ring provided on the pin member. Cylinder silencer. 4. The stopper member according to claim 1 or 2, wherein the stopper member is a ring member provided over substantially the entire circumference of the support ring, and the elastic members are provided on front and rear end surfaces of the ring member in the optical axis direction. A silencing mechanism for the lens barrel.