JP2006251581A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel for a camera, the barrel in which a movable cylinder such as an operation ring can be securely fixed to a fixing cylinder by the use of a fixing screw without causing a thrust mark or deformation. <P>SOLUTION: In the lens barrel 1 for the camera, an annular rubber band 5 is bonded and fixed to the circumferential face of the fixed cylinder 2. The fixing screw 4 is attached to part of the operation ring 3 disposed opposite to the rubber band 5. When the operation ring 3 is rotated to a prescribed position and the fixing screw 4 is fastened, the leading end face 4c of the leg of the fixing screw bites the rubber band 5 and thus the operation ring 3 can be fixed with a large fixing force. Since the pressing force of the fixing screw 4 is relieved by the rubber band 5, a thrust mark is not left on the circumferential face of the fixed cylinder. An amount that the fixing screw 4 bites the rubber band 5 increases according to an an amount that the fixing screw 4 is fastened. Accordingly, an operating force necessary to fasten the fixing screw 4 increases. This enables an operator to know through the operating resistance of the fixing screw that the fixing screw 4 has been sufficiently fastened, and prevents the operator from excessively fastening the fixing screw to such a degree that the fixing cylinder 2 is deformed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens barrel of a camera provided with a fixed cylinder and a movable cylinder movable along the outer peripheral surface thereof, and more particularly to an improvement of a mechanism for fixing the movable cylinder to the fixed cylinder.

The lens barrel of the camera includes a fixed cylinder that is fixed to the camera body side, and an operation ring that is disposed so as to surround the outer peripheral surface of the fixed cylinder in a coaxial state. When the operating ring is rotated, the movable lens group moves toward or away from the fixed lens group mounted in the fixed cylinder along the optical axis. Can do. A fixing screw is attached to the operation ring from the outside, and when the fixing screw is screwed in, the tip end surface of the leg is pressed against the circular outer peripheral surface of the inner fixing cylinder. As a result, the operating ring can be fixed at a predetermined rotational position. Such a fixing mechanism of the operating ring is disclosed in, for example, Patent Document 1.
JP 2003-315651 A

  However, the mechanism for fixing the operation ring by screwing the fixing screw attached to the operation ring and pressing the leg tip end face against the fixed cylinder has the following problems. First, the front end surface of the leg of the fixing screw is generally a flat surface, and the side of the fixing cylinder to which it is pressed is generally a circular outer peripheral surface. For this reason, since it becomes a line contact state between these and a wide contact area cannot be ensured, it is difficult to obtain the frictional force required to fix the operating ring securely. Therefore, there is a problem that the force for fixing the operation ring is weak and the operation ring easily moves.

  In addition, if the fixing screw is tightened strongly to increase the force for fixing the operation ring, stress concentration occurs at the portion of the circular outer peripheral surface of the fixing cylinder where the tip surface of the fixing screw is in contact with the line, and a dent is formed at that portion. May remain.

  Further, when the dent remains, when the front end surface of the fixing screw is pressed against the outer peripheral surface of the fixing cylinder in the vicinity of the dent, the pressed front end surface of the fixing screw is easily displaced toward the dent. Therefore, when the fixing screw is tightened to fix the operation ring in the vicinity of the dent, the operation ring is slightly moved toward the dent side. For this reason, the operation ring cannot be fixed in the vicinity of the portion where the dent remains. In other words, there are cases where the fixed position of the operating ring cannot be finely adjusted in the vicinity of the dent position.

  In addition to this, if the fixing screw is tightened too much, the fixing cylinder may be deformed. When the lens optical system is incorporated inside the fixed cylinder, there is a possibility that adverse effects such as lens deformation and optical axis misalignment will be adversely affected.

  As described above, in the conventional operation ring fixing mechanism using the fixing screw, the force for fixing the operation ring is generally weak, and if the fixing screw is tightened excessively so that the operation ring can be securely fixed, the fixing ring is hit. Marks or deformation may occur. Therefore, it has been difficult to securely fix the operation ring by properly tightening the fixing screw.

  In view of these points, an object of the present invention is to provide a camera equipped with a mechanism that can securely fix a movable cylinder such as an operation ring to a fixed cylinder without generating dents or deformation using a fixing screw. It is to propose a lens barrel.

In order to solve the above problems, the lens barrel of the camera of the present invention is:
A fixed cylinder;
A movable cylinder arranged coaxially in a state surrounding the outer peripheral surface of the fixed cylinder;
In order to fix the movable cylinder to the fixed cylinder, a fixed screw provided with a leg tip surface that is screwed into the movable cylinder from the outside and can be pressed against the outer peripheral surface of the fixed cylinder;
And an elastic member attached to a portion of the outer peripheral surface of the fixed cylinder with which the tip end surface of the fixing screw abuts.

  In the present invention, when a fixing screw for fixing the movable cylinder is tightened, the leg end surface is pressed and fixed onto the outer peripheral surface of the fixed cylinder from above the elastic member. The front end surface of the leg portion of the fixing screw bites into the elastic member on the fixed cylinder side, and both are brought into a surface contact state, and the frictional resistance force therebetween increases. At the same time, the resistance force when the leg portion of the fixing screw tends to be displaced with respect to the elastic member due to the biting in increases. Therefore, since the fixing force of the movable cylinder generated by tightening the fixing screw is increased as compared with the conventional case, the movable cylinder can be reliably fixed to the fixed cylinder.

  Even if the fixing screw is tightened too much, stress concentration is relaxed by the elastic member, so that no dent remains on the outer peripheral surface of the fixed cylinder.

  Furthermore, when the fixing screw is tightened, the leg tip end surface bites into the elastic member, so that the fixing screw tightening resistance increases. The operator can know that the fixing screw has been sufficiently tightened by sensing this increase in resistance force from the fingertip. Therefore, it is possible to prevent excessive tightening of the fixing screw that would deform the fixing cylinder.

  Here, when the movable cylinder is rotatable about the central axis of the fixed cylinder along the outer peripheral surface of the fixed cylinder, the elastic member is opposed to the leg end surface of the fixed screw. An annular elastic plate attached to the portion of the outer peripheral surface of the fixed cylinder that is being used can be employed.

  Examples of the movable cylinder that rotates in this way include an operation ring for moving the movable lens in the optical axis direction and a cylindrical tripod mount for mounting a tripod.

  Further, when the movable cylinder is movable along the outer peripheral surface of the fixed cylinder in a direction along the central axis of the fixed axis, the elastic member is moved to the center of the outer peripheral surface of the fixed cylinder. What is necessary is just to attach to the some site | part distant in the direction of the axis line.

  Furthermore, when the movable cylinder is rotatable about the central axis of the fixed cylinder along the outer peripheral surface of the fixed cylinder and is movable in the direction of the central axis, the elastic member is An annular elastic plate attached to a plurality of parts separated in the direction of the central axis on the outer peripheral surface of the fixed shaft can be employed.

  Here, a cylindrical hood can be mentioned as a movable cylinder which rotates and moves.

  In the lens barrel of the camera of the present invention, the distal end surface of the leg of the fixing screw attached to the movable cylinder is pressed against the outer peripheral surface of the fixed cylinder via the elastic member to fix the movable cylinder. Therefore, since the fixing force of the movable cylinder by the fixing screw can be increased as compared with the conventional case, the movable cylinder can be reliably fixed at a desired position. In addition, since the stress concentration on the outer peripheral surface of the fixed cylinder when the fixing screw is tightened can be relieved by the elastic member, no dent remains on the outer peripheral surface of the fixed cylinder. Furthermore, when tightening the fixing screw, the tightening resistance increases according to the amount of biting into the elastic member, so the operator knows whether the fixing screw has been tightened sufficiently from the sense of operation resistance of the fixing screw. Can do. Therefore, it is possible to prevent the adverse effect that the fixed cylinder is deformed by excessive tightening.

  Hereinafter, examples of a lens barrel to which the present invention is applied will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a side view showing the lens barrel according to the first embodiment in a partial cross section, and FIG. 2 is a schematic cross section of a portion cut along the line II-II. The lens barrel 1 includes a fixed cylinder 2, a rotatable operation ring 3 that surrounds the outside of the fixed cylinder 2 in a coaxial state, and a fixing screw 4 for fixing the operation ring 3.

  At the rear end of the fixed cylinder 2, a mounting portion 2a that can be mounted on a mount portion of a camera body (not shown) is formed. The outer peripheral surface portion on the front side of the mounting portion 2a has a constant width for preventing slippage. Is a grip portion 2b for operation having an uneven surface formed in the circumferential direction. An annular guide flange 2 c for guiding the rotation of the operation ring 3 is formed at a middle portion in the front-rear direction of the fixed cylinder 2. A shallow annular groove 2d having a constant width extending in the circumferential direction is formed in a rear portion of the guide flange 2c, and an annular rubber band 5 having a constant thickness and a constant width is formed in the groove 2d. The (elastic member) is bonded and fixed.

  The operation ring 3 is a cylindrical tube as a whole, and an annular step surface 3a projecting inward is formed on the inner peripheral surface portion in the middle of the front-rear direction. The annular step surface 3 a is supported by the guide flange 2 c of the fixed cylinder 2 in a slidable state. Therefore, the operation ring 3 can be rotated with respect to the fixed cylinder 2 around the central axis of the fixed cylinder, that is, the central axis 1 a of the lens barrel 1.

  The fixing screw 4 is attached to a portion of the operation ring 3 facing the rubber band 5. That is, a screw hole 3b is formed in a portion of the operation ring 3 facing the rubber band 5, and the fixing screw 4 is screwed into the screw hole 3b in a posture facing the central axis 1a from the outside.

  The fixing screw 4 includes a large-diameter head portion 4a as an operation knob and a small-diameter leg portion 4b protruding coaxially from the head portion 4a, and a male screw is engraved on the outer peripheral surface portion of the leg portion 4b. Yes. The front end surface 4c of the leg 4b is a flat surface. A retaining member 6 is attached to the distal end portion of the leg 4b so that the fixing screw 4 does not come out from the screw hole 3b of the operation ring 3.

  Note that, in the fixed cylinder 2, for example, a fixed lens group of the zoom lens optical system is incorporated in a rear part thereof, and a movable lens group is incorporated in a front part thereof. The lens holder of the movable lens group is attached to the fixed cylinder 2 so as to be movable in the front-rear direction. The lens holder is connected to the operation ring 3 via a cylindrical cam mechanism or the like. When the operation ring 3 is rotated, the lens holder moves in the front-rear direction. Therefore, the movable lens can be moved by operating the operation ring 3. Since such a mechanism is generally employed in a lens barrel of a camera, detailed description and illustration thereof are omitted.

  In the thus configured lens barrel 1 of this example, as shown in FIGS. 1 and 2, the fixing screw 4 is loosened, the operation ring 3 is rotated, and the movable lens group is moved to perform focusing and the like. After this, the fixing screw 4 is tightened to fix the operation ring 3 to the fixed cylinder 2 to maintain the focused state.

  3A and 3B are a partial cross-sectional view showing a state in which the fixing screw 4 is tightened, and a partial enlarged cross-sectional view showing a leg end portion of the fixing screw 4. As shown in these drawings, when the fixing screw 4 is tightened, the leg tip end surface 4c is in a state of being bitten into the rubber band 5 by a predetermined amount. As a result, the leg tip surface 4 c is in surface contact with the surface of the rubber band 5. Therefore, compared with the state where the flat leg end surface is in line contact with the circular outer peripheral surface of the fixed cylinder as in the prior art, the frictional force between them is greatly increased. Therefore, the fixing force of the operation ring 3 by the fixing screw 4 increases, and the operation ring 3 does not move from the fixed position.

  Further, as can be seen from FIG. 3 (b), the leg tip surface 4c of the fixing screw 4 bites into the rubber band 5, so that the rubber band 5 has an annular inner wall of a predetermined height surrounding the leg tip surface 4c. A portion 5a is formed. When the leg portion 4b of the fixing screw 4 tries to shift laterally, the fixing screw 4 hits the annular inner wall portion 5a and is prevented from shifting. Therefore, even with such elastic deformation of the rubber band 5, the fixing force of the operation ring 3 by the fixing screw 4 increases.

  Furthermore, since the leg tip end surface 4c of the fixing screw 4 is pressed against the outer peripheral surface of the fixed cylinder 2 via the rubber band 5, a part of the outer peripheral surface of the fixed cylinder 2 is strongly pressed, and a dent remains there. There will be no negative effects.

  In addition to this, as the fixing screw 4 is tightened, the amount of biting into the rubber band 5 of the leg tip surface 4c increases, and the operating resistance of the fixing screw 4 increases. Therefore, the operator can know that the fixing screw 4 is sufficiently tightened from the operational feeling. As a result, it is possible to prevent the adverse effect that the fixing screw 4 is excessively tightened and the fixing cylinder 2 is deformed.

(Embodiment 2)
4 and 5 are side views each showing a partial cross section of a lens barrel of a camera according to Embodiment 2 of the present invention. The lens barrel 10 of the present example includes a fixed cylinder 12 attached to the camera body side, an operation ring 13 coaxially attached so as to surround a middle portion of the fixed cylinder 12 in the front-rear direction, and a fixed cylinder 12. A hood 17 that is coaxially attached so as to surround the front part protruding forward of the operation ring 13 and a cylinder that is coaxially attached so as to surround the rear part of the fixed cylinder 12 protruding rearward of the operation ring 13. A tripod seat 18 is provided.

  The operation ring 13 can be rotated around the central axis 10 a along the circular outer peripheral surface of the fixed cylinder 12, and can be fixed to the fixed cylinder 12 by a fixing screw 14. The fixing mechanism using the fixing screw 14 is the same as that of the lens barrel 1 of the first embodiment, and the fixing screw 14 and a rubber band (not shown) on the fixing cylinder side against which the front end surface of the leg is pressed. And.

  The front side portion of the fixed cylinder 12 to which the hood 17 is attached has a circular outer peripheral surface 12a, and the hood 17 has a cylindrical shape that is slightly larger than the circular outer peripheral surface 12a. An annular slider 17 a that protrudes inward is formed at the rear end portion of the circular inner peripheral surface of the hood 17, and the annular slider 17 a extends along the circular outer peripheral surface 12 a of the fixed cylinder 12 with the central axis 10 a. And can be slid in the direction of the central axis 10a (front-rear direction).

  The hood 17 of this example can be slid between the storage position 17A shown in the upper half part in FIG. 4 and the drawer position 17B shown in the lower half part. The storage position 17 </ b> A is defined by the rear end edge 17 b of the hood coming into contact with the annular end surface 12 b formed at the middle position of the fixed cylinder 12. The drawing position 17B is defined by the annular slider 17a of the hood 17 coming into contact with the annular end surface 12c formed at the front end portion of the fixed cylinder 12.

  The hood 17 can be fixed to the storage position 17A and the drawer position 17B by a fixing screw 19, respectively. That is, a fixing screw 19 is attached to the rear end portion of the hood 17. In addition, an annular rubber band 20 is bonded and fixed to the fixed cylinder 12 so as to surround an outer peripheral surface portion facing the fixing screw 19 at the storage position 17A. Similarly, an annular rubber band 21 is bonded and fixed to the outer peripheral surface portion of the fixed cylinder facing the fixing screw 19 at the pull-out position 17B. The structure of the fixing screw 19 is the same as that of the fixing screw 4 in the first embodiment. In addition, the operational effect when the fixing screw 19 is tightened is the same as that in the first embodiment.

  Next, the cylindrical tripod seat 18 is mounted between a pair of front and rear annular step surfaces 12d and 12e formed on the outer peripheral surface portion of the fixed cylinder 12, and the central axis 10a is centered along these. It can be rotated as. The cylindrical tripod seat 18 is a cylinder having a constant thickness as a whole, and a thick tripod mounting portion 18a is formed in a part of the circumferential direction of the cylindrical tripod seat 18, and a tripod main body (not shown) is attached thereto. It is supposed to be.

  A fixing screw 22 is attached to a central portion of the cylindrical tripod seat 18 in the axial direction. An annular rubber band 23 is bonded and fixed to the outer peripheral surface portion of the fixed cylinder 12 facing the fixing screw 21. The structure of the fixing screw 22 is basically the same as that of the fixing screw 4 in the first embodiment. In addition, the operational effect when the fixing screw 22 is tightened is the same as that in the first embodiment.

  Thus, in the lens barrel 10 of the camera of this example, the present invention is applied as a fixing mechanism for the operation ring 13 and the cylindrical tripod seat 18 that are attached to the fixed barrel 12 in a rotatable state. . Similarly, the present invention is applied as a fixing mechanism of the hood 17 that is attached to the fixed cylinder 12 so as to be rotatable and slidable. Therefore, these members can be reliably fixed at the operation position. Further, no dent remains on the outer peripheral surface portion of the fixed cylinder 12, and the fixed cylinder 12 is not deformed.

(Other embodiments)
In each of the above examples, an annular rubber band is bonded and fixed to the outer peripheral surface portion of the fixed cylinder. If the rotation range of the movable operating ring, hood, and tripod seat is limited, place elastic members such as rubber bands in the area that includes the movement range of the fixing screws 4, 14, 19, and 22. That's fine. Further, when the hood is fixed at three or more positions in the axial direction, an elastic member may be arranged at a portion corresponding to the fixed position.

  On the other hand, in each of the above examples, the elastic member is bonded and fixed to the outer peripheral surface portion of the fixed cylinder. Instead of this, or together with this, as shown in FIG. 6, it is possible to fix the elastic piece 5A to the leg end surface 4c of the fixing screw 4A.

It is a side view which shows the lens-barrel to which this invention is applied in a partial cross section. It is a schematic sectional drawing of the lens-barrel of FIG. (a) is a fragmentary sectional view which shows the state which tightened the fixing screw of the lens barrel of FIG. 1, (b) is a partial expanded sectional view which shows the leg part front-end | tip of a fixing screw. It is a side view which shows the lens-barrel to which this invention is applied in a partial cross section. It is a side view which shows a different site | part in a cross section from the lens barrel of FIG. It is explanatory drawing which shows another example of a fixing screw.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10 Lens barrel 2, 12 Fixed cylinder 3 Operation ring 4, 14, 19, 22 Fixing screw 4a Leg part front end surface 5, 20, 21, 23 Rubber band 5a Annular inner wall part 6 Retaining stopper 17 Hood 18 Cylindrical tripod seat

Claims (7)

A fixed cylinder;
A movable cylinder arranged coaxially in a state surrounding the outer peripheral surface of the fixed cylinder;
In order to fix the movable cylinder to the fixed cylinder, a fixed screw provided with a leg tip surface that is screwed into the movable cylinder from the outside and can be pressed against the outer peripheral surface of the fixed cylinder;
A lens barrel for a camera, comprising: an elastic member attached to a portion of the outer peripheral surface of the fixed barrel that contacts the tip end surface of the fixing screw. In claim 1,
The movable cylinder is rotatable about the central axis of the fixed cylinder along the outer peripheral surface of the fixed cylinder,
The lens barrel of a camera, wherein the elastic member is an annular elastic plate attached to a portion of the outer peripheral surface of the fixed tube facing the leg tip end surface of the fixed screw. In claim 1,
The movable cylinder is movable in a direction along the central axis of the fixed axis along the outer peripheral surface of the fixed cylinder.
The lens barrel of a camera, wherein the elastic member is attached to a plurality of parts separated in the direction of the central axis on the outer peripheral surface of the fixed cylinder. In claim 1,
The movable cylinder is rotatable about the central axis of the fixed cylinder along the outer peripheral surface of the fixed cylinder, and is movable in the direction of the central axis.
The lens barrel of a camera, wherein the elastic member is an annular elastic plate attached to a plurality of parts separated in the direction of the central axis on the outer peripheral surface of the fixed shaft. In claim 2,
The lens barrel of a camera, wherein the movable cylinder is an operation ring for moving the movable lens in the optical axis direction. In claim 2,
The lens barrel of a camera, wherein the movable tube is a cylindrical tripod mount for mounting a tripod. In claim 4,
The lens barrel of a camera, wherein the movable barrel is a cylindrical hood.

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