JPH0449610Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a lens barrel used in a single-lens reflex camera or a video camera, and particularly relates to a holding frame for a group of lenses for focus adjustment. This invention relates to means for fixing to a distance ring.

(Prior Art) For example, in a zoom lens, the first group on the subject side generally has a focus adjustment function, and a distance (indication) ring is provided at the front end of the lens barrel to manually operate this function. There is.

Here, an example of a conventional zoom lens barrel is shown in the fourth section.
This will be explained based on the diagram.

The lens barrel main body 11, the fixing ring 12, and the master lens part fixing barrel 13 are fixed together with screws (not shown) or the like.

Flange portion 11a at the front end of the lens barrel main body 11
A cam barrel 14 is held between the lens barrel 12 and the fixed ring 12, and the cam barrel 14 is configured to be rotatable and slidable on the inner circumferential surface of the lens barrel body 11. Further, the cam cylinder 14
is connected and fixed to a zoom ring 15 rotatably provided on the outer peripheral surface of the lens barrel body 11.

Furthermore, the holding frame 17 of the variable power lens group 16 and the holding frame 19 of the correction lens group 18 are connected to a plurality of guides in the optical axis direction fixed between the flange portion 11a of the lens barrel body 11 and the fixed ring 12. They are each slidably fitted onto the shaft 20. Each of the holding frames 17 and 19 has through holes 17a and 19a for fitting the guide shaft 20 thereinto, and has protrusions 17b and 19b as cam follower members on the side surfaces, and these protrusions 17b and 19b have The cam cylinder 1
It is slidably fitted into cam grooves 14a and 14b formed in 4.

Further, a fixed lens 21 is fitted into the fixed ring 12. Furthermore, holding frames 23 and 24 of the master lens group 22 are fitted inside the master lens portion fixing cylinder 13 and fixed with screws 25.

Reference numeral 26 denotes a holding frame that holds a focusing lens group 27, which is a lens group for adjusting the focus. That is, a helicoid threaded portion 26b formed on the rear outer circumferential surface of the holding frame 26 is engaged with a helicoid threaded portion 11b formed on the inner circumferential surface of the front end portion of the lens barrel main body 11.

Further, an index decorative ring 2 is provided on the outer peripheral surface of the lens barrel main body 11.
On the other hand, a distance ring 29 is fixed to the outer circumferential surface of the flange portion 26a at the front portion of the holding frame 26 with a compression screw 30 or the like. Furthermore, a crimping screw 30 is provided on the outer peripheral surface of this distance ring 29.
A rubber ring 31 is fixed so as to cover it. Note that the distance ring 29 has a stepped portion 29a formed on the rear inner peripheral surface of the distance ring 29 and the lens barrel main body 1.
The rotation angle with respect to the lens barrel body 11 is regulated by engagement with a protrusion 11c formed on the outer peripheral surface of the front end of the lens 1, and the distance to the in-focus point by the focusing lens group 27, for example, from a short distance (1 m) to It displays up to infinity (∞).

Further, a front end ring 32 is screwed onto the inner peripheral surface of the front end portion of the distance ring 29, and is brought into contact with the holding frame 26 from the front. That is, the filter threaded portion 29b formed on the front inner circumferential surface of the distance ring 29,
A threaded portion 32 formed on the outer peripheral surface of the front end ring 32
b are engaged.

When assembling and adjusting the lens, the distance ring 29 fitted to the lens barrel body 11 is at a position indicating infinity, and further rotation is prevented by the stopper consisting of the protrusion 11c and the stepped portion 29a. In this state, the holding frame 26 is screwed into the helicoid screw portion 11b of the lens barrel body 11, and the position in the optical axis direction is adjusted so that an object at an infinite distance is in focus. Next, screw 3 screwed onto distance ring 29.
0 to the outer peripheral surface of the holding frame 26, the distance ring 29 and the holding frame 26 are fixed. Next, the filter threaded portion 29 on the inner circumferential surface of the distance ring 29
b, screw the front end ring 32 into the front end of the holding frame 26 until it touches the front surface of the holding frame 26, and arrange the appearance as a nameplate.

(Problems to be Solved by the Invention) As described above, conventionally, by crimping the screw 30 screwed onto the distance ring 29 onto the outer peripheral surface of the holding frame 26 for the focusing lens group 27, The holding frame 26 and the distance ring 29 are integrated or fixed at an arbitrary angular position. However, if the screws 30 become even slightly loose, slippage will occur between the outer peripheral surface of the holding frame 26 and the screws 30, so the screws 30 must be firmly screwed in.
Workability was very poor.

The present invention aims to solve these problems, and allows the focus adjustment and distance ring position to be adjusted in the same way as before, and also allows the holding frame and distance ring to be reliably integrated without using screws. The object of the present invention is to provide a lens barrel with excellent assembly workability.

[Structure of the idea]

(Means for Solving the Problems) The lens barrel of the present invention includes a lens barrel body 11, and helicoid threaded portions 11b, 26b on this lens barrel body 11.
A holding frame 26 is connected to the holding frame 26 so as to be rotatably advanced and retracted and holds a lens group 27 for focus adjustment, and a holding frame 26 is fixed to the outer circumferential side of this holding frame 26 and is rotatable outside a predetermined distance range with respect to the lens barrel main body 11. The distance ring 29, which is prevented from being
and a front end ring 32 in contact with the holding frame 2.
A locking piece 33 that is displaceable in the radial direction is provided on the front end surface of 6.
34, and on the other hand, the locking pieces 33 and 34 of the holding frame 26 are engaged with the inner peripheral surface of the distance ring 29 so that the distance ring 29 and the holding frame 2
6. A mating surface 29c is formed to prevent mutual movement in the circumferential direction, and the front end ring 32 is engaged with the locking pieces 33, 34 of the holding frame 26 on the abutting surface of the holding frame 26. A regulating portion 32c is formed to prevent displacement of the stopper piece in the radial direction and maintain engagement between the locking pieces 33, 34 and the engagement surface 29c.

(Function) In the lens barrel of the present invention, when assembling and adjusting the lens, the distance ring 29 is assembled to the lens barrel body 11, and the holding frame 26 is attached to the helicoid screw portions 11b, 26b. Combine by. At that time, the locking pieces 33, 34 of the holding frame 26 are displaced inward in the radial direction, and the locking pieces 33, 34 of the holding frame 26 are displaced inward in the radial direction.
34 and the engagement surface 29c of the distance ring 29 are not engaged, the holding frame 26 is moved independently of the distance ring 29.
is rotated forward and backward relative to the lens barrel body 11, and the position of the lens group 27 for focus adjustment is adjusted, for example, to infinity (∞). On the other hand, in the normal state, the locking piece 3
3 and 34 are engaged with the engagement surface 29c, and the holding frame 2
6 and distance ring 29 are restricted from moving in the circumferential direction. When the front end ring 32 is screwed onto the inner circumferential surface of the front end portion of the distance ring 29 using the threaded portions 29b and 32b and brought into contact with the holding frame 26, the regulating portion 32 of the front end ring 32
c is engaged with the locking pieces 33, 34 of the distance ring 29, and displacement of the locking pieces 33, 34 in the radial direction is prevented, so that the locking pieces 33, 34 of the holding frame 26
34 and the engagement surface 29c of the distance ring 29 is reliably maintained, and the distance ring 29 and the holding frame 26 are
That is, the lens group 27 for focus adjustment is in a fixed state. In this state, the distance ring 29 and the holding frame 26 rotate integrally with respect to the lens barrel body 11.

(Embodiment) An embodiment of the lens barrel of the present invention will be described below with reference to FIGS. 1 to 3.

The lens barrel of this embodiment basically has the same structure as the lens barrel shown in FIG. 4, so corresponding parts will be described with the same reference numerals.

At the front end of the lens barrel body 11, that is, the end on the subject side, a helicoid threaded portion 11b is formed on the inner peripheral surface, and a protrusion 11c is formed on the outer peripheral surface.

The holding frame 26 that holds the focusing lens group 27, which is a lens group for adjusting the focus, has a helicoid screw portion 26b formed on the rear side, that is, on the image forming surface side, to engage with the helicoid screw portion 11b. , a flange portion 26a is formed on the end surface portion on the subject side. On the subject side of the flange portion 26a, locking pieces 33 and 34 are integrally formed, which face each other across the optical axis and whose outer peripheries are located on the same circumference as the outer periphery of the flange portion 26a in a normal state. There is. These locking pieces 33 and 34 each have a normally open slit 33 between them and the flange portion 26a.
a, 34a, and are formed to extend in the circumferential direction and face in opposite directions, that is, clockwise and counterclockwise, and to be elastically displaceable in the radial direction with respect to the optical axis. In addition, engagement surfaces 33b and 34b each consisting of a large number of filaments extending in the optical axis direction are formed on the outer circumferential surfaces of these locking pieces 33 and 34, respectively. Further, on the subject-side surfaces of the locking pieces 33 and 34, a projecting piece 33c extending in the optical axis direction,
34c are formed respectively.

The inner peripheral surface of the distance ring 29 that can be fitted onto the outer peripheral side of the lens barrel main body 11 has an annular stepped portion 29a with a portion cut out, and a mating surface 29c consisting of a large number of key grooves in the optical axis direction. and the filter threaded portion 29b,
They are formed in order from the imaging plane side to the subject side. The stepped portion 29a is formed by the protrusion 11 of the lens barrel main body 11.
By coming into contact with c, the rotation of the distance ring 29, which displays the distance to the in-focus point by the focusing lens group 27, relative to the lens barrel body 11 is restricted to within a range corresponding to a predetermined distance range. be. Further, the engagement surface 29c is connected to the locking piece 3.
3 and 34 to prevent the holding frame 26 and the distance ring 29 from moving in the circumferential direction, and the engaging surface 29c and the locking pieces 33 and 34 have a mating habit. In addition, these locking pieces 3
The meshing surfaces 33b and 34b mesh with the meshing surface 29c to enhance the meshing effect.

A front end ring 3 having a threaded portion 32b formed on the outer peripheral surface to mesh with the filter threaded portion 29c of the distance ring 29.
2, the protruding pieces 3 of the locking pieces 33 and 34 are provided on the rear surface of the imaging surface side that is the abutting surface with the holding frame 26.
An annular recess 32c is formed as a restriction portion to be engaged with the projections 3c and 34c, and the diameter of the recess 32c is equal to the distance between the pair of protrusions 33c and 34c.

The lens barrel of the above embodiment is assembled as follows.

First, the distance ring 29 is fitted to the lens barrel body 11, and the end face of the stepped portion 29a of the distance ring 29 is brought into contact with the protrusion 11c of the lens barrel body 11, and the rotation start position, that is, infinity (∞) is displayed. position.

Next, the holding frame 26 is screwed into the helicoid threaded portion 11b of the lens barrel body 11, and the position of the focusing lens group 27 on the optical axis is moved in the direction of the image plane. Then, the position of the focusing lens group 27 is adjusted so that the object at infinity (∞) is in focus. At this time, as shown in FIG. 2, the locking pieces 34 (and 33) of the holding frame 26 and the meshing surface 29c of the distance ring 29 have a meshing habit.
The locking pieces 33 and 34 and the engagement surface 29 are arranged so that the holding frame 26 can be rotated independently of the distance ring 29.
In order to release the engagement with c, a pair of locking pieces 33,
The protruding pieces 33c and 34c of 34 are pressed inward in the radial direction to displace the locking pieces 33 and 34 in the same direction.

When this infinite (∞) position adjustment is completed and the pressure on the projecting pieces 33c and 34c is released, the locking piece 3
The meshing surfaces 33b, 34b of No. 3, 34 and the meshing surface 29c of the distance ring 29 are in meshing state. Next, the front end ring 32 is screwed onto the end of the distance ring 29 on the subject side. Then, the projections 33c and 34c of the locking pieces 33 and 34 are inserted into the recess 32c of the distance ring 29, and the flange 26a of the holding frame 26 is brought into contact with the front surface of the stepped portion 29a of the distance ring 29 and the front end ring 32. The holding frame 26 and the distance ring 29 are held in a state in which mutual movement in the optical axis direction is prevented. At the same time, the engagement surfaces 33b, 34b of the locking pieces 33, 34 are caused by the engagement between the recess 32c and the projecting pieces 33c, 34c.
The engagement between the meshing surface 29c of the distance ring 29 and the distance ring 29 is reliably maintained, and the movement of the holding frame 26 and the distance ring 29 in the circumferential direction is reliably prevented, so that the holding frame 26 and the distance ring 29 are integrally formed. The fixed state is maintained. In this state, the holding frame 26 and the distance ring 29 integrally move forward and backward relative to the lens barrel body 11.

In this way, according to the above configuration, the holding frame 26 and the distance ring 29 can be fixed together without using screws. Then, the holding frame 26 and the distance ring 29
In addition, there is an elastically displaceable locking piece 3 that restricts mutual movement of the holding frame 26 and distance ring 29 in the circumferential direction.
3, 34 and a mating surface 29c are formed, and these locking pieces 33, 34 and the mating surface 29c have a mating habit, so that the locking pieces 33, 34 and the mating surface 29c have a mating habit.
The position adjustment and subsequent fixing work using the front end ring 32 can be separated. In other words, even if the optical axis is adjusted horizontally and then the optical axis is set vertically for fixing work, the adjusted state will not be lost, which greatly improves work efficiency.

In addition, once adjusted and fixed, the locking piece 33,
34 is prevented from being displaced by the front end ring 32, so
The adjustment state will not shift during use, improving durability.

In the above embodiment, for the sake of explanation, the distance ring 29 is provided with a distance value, but it goes without saying that the distance display may be omitted in a lens barrel that is integrated with the AF camera.

[Effect of idea]

According to the present invention, the displaceable locking piece formed on the holding frame of the lens group for focus adjustment is engaged with the engagement surface formed on the distance ring for distance display, and the front end ring is screwed into the distance ring. By abutting the retaining frame with the retaining frame, the retaining frame and the distance ring can be easily and reliably fixed without using screws or the like, and also prevent the retaining frame and the distance ring from moving in the circumferential direction. Since the locking piece and the engaging surface have a mating habit, for example, infinite position adjustment and subsequent fixing work can be separated, further improving work efficiency.Furthermore, after fixing, the front end ring Since displacement of the locking piece is prevented, the adjusted state does not shift during use, and durability is improved.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing one embodiment of the lens barrel of the present invention, Fig. 2 is a front view of its main parts, Fig. 3 is a sectional view thereof, and Fig. 4 is an example of a conventional lens barrel. FIG. DESCRIPTION OF SYMBOLS 11... Lens barrel body, 11b... Helicoid screw part, 26... Holding frame, 26b... Helicoid thread part, 27... Focusing lens group which is a lens group for focus adjustment, 29... Distance ring, 29b...
...Threaded portion, 29c...Matching surface, 32...Front end ring,
32b...threaded part, 32c...recessed part as a regulating part, 33, 34...locking piece.

Claims (1)

[Scope of Claim for Utility Model Registration] A lens barrel body; A holding frame that is rotatably connected to the lens barrel body through a helicoid thread and holds a group of lenses for focus adjustment; and a holding frame fixed to the outer circumferential side of the holding frame. a distance ring which is prevented from rotating outside a predetermined distance range with respect to the lens barrel body; and a front end screwed into the inner peripheral surface of the front end of the distance ring by a threaded portion and abutted against the holding frame. a ring, a locking piece movable in the radial direction is formed on the front end surface of the holding frame, and the locking piece of the holding frame is engaged with the inner circumferential surface of the distance ring so that the distance between the locking pieces is A mating surface is formed to prevent the ring and the holding frame from moving in the circumferential direction, and the front end ring is engaged with a locking piece of the holding frame on the abutment surface of the front end ring with the holding frame, and is engaged with a locking piece of the holding frame in the radial direction of the locking piece. What is claimed is: 1. A lens barrel characterized in that a regulating portion is formed to prevent displacement of the locking piece and maintain engagement between the locking piece and the engagement surface.