JPH0522890Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fixing structure for a lens holding cylinder of a focusing lens.

(Prior Art) The structure of a zoom lens barrel will be explained with reference to FIG. 1, and the fixing structure of a lens holding barrel of a focusing lens of a conventional photographing lens barrel will be explained with reference to FIG.

FIG. 1 is a cross-sectional view of a zoom lens barrel,
First movable lens group L1 (focusing lens)
The lens holding tube 1 (31 in Fig. 4) that holds the
It is supported by the first moving frame 10 via helicoid screws 1a (31a in FIG. 4) and 10a. This first moving frame 10 is slidably fitted to the inner peripheral surface of the fixed cylinder 6. The first moving frame 10 holds the lens group L4 at its rear end. The members 8 and 9 that hold the lens groups L2 and L3, respectively, are both slidably fitted to the inner circumferential surface of the moving frame 10.

The fixed cylinder 6 has three linear guide grooves 6a, 6b, 6.
It has c. The first moving frame 10 is provided with two escape grooves 10b and 10c. The cam cylinder 7 is rotatably fitted to the outer periphery of the fixed cylinder 6.

The zoom operation member 5 is rotatably fitted into a fixed barrel 6 and a housing member 4 that is integrally fixed to the fixed barrel 6.

The cam cylinder 7 has a notch groove 7d at the rear end, and a zoom operation member 5 that is operated during a zooming operation.
The flange protrusion 5a is engaged with the notch groove 7d. The zoom cam barrel 7 has cam grooves 7a, 7.
b, 7c are provided. In the cam groove 7a, a pin 20 implanted in the holding member 8 is inserted into the relief groove 10.
b. It penetrates and engages the straight guide groove 6a. Similarly, a pin 22 implanted in the holding member 9 penetrates the escape groove 10c and the linear guide groove 6a and engages with the cam groove 7c. Further, the pin 21 implanted in the first moving frame 10 is inserted into the cam groove 7b in the straight groove 6.
It penetrates and engages b.

The focusing ring 3 is a housing member 4
The focusing ring 3 is rotatably connected to the focusing ring 3 via threaded portions 3a and 4a. A linear groove 3b is provided on the inner peripheral surface of the focusing ring 3, and a rotation restricting pin 12 is attached to the outer peripheral surface of the focusing ring 3. As shown in Fig. 4, a protrusion 32b (2b in Fig. 1) of an interlocking member 32 (2 in Fig. 1) is engaged with the groove 3b.
This rotation restricting pin 12 is slidably fitted into a notched groove 4b provided in a housing member 4 fixed to a fixed barrel 6, and restricts the rotation range of the focusing ring 3 together with the notched groove 4b.

As shown in FIG. 4, the interlocking member 32 is provided with a convex portion 32a at a position facing a V-groove 31b formed in the circumferential direction on the outer periphery of the holding cylinder 31.
An adjustment screw 23 is provided to penetrate through 2a. The lens holding tube 31 is provided to fit into this convex portion 32a, and the V groove 31b of the holding tube 31 and the adjustment screw 23
are engaged with each other to be integrally coupled to the interlocking member 32.

This focusing operation of the zoom lens barrel is performed because when the focusing ring 3 is rotated, the protrusion 32b of the interlocking member 32 and the linear groove 3b engage with each other, so that the interlocking member 32 and the linear groove 3b are engaged with each other. The lens holding cylinder 31 is rotated, and the focusing lens L1 is extended along the straight groove 3b via the helicoid screws 31a and 10a. Further, in the zooming operation, when the zoom operation ring 5 is rotated, the zoom cam barrel 7 is rotated via the flange protrusion 5a and the notch groove 7d. This is done by moving L4 in the optical axis direction in a predetermined relationship.

As shown in FIG. 4, the adjustment screw 23 of the interlocking member 32 is engaged with the groove surface of the V-groove 31b of the lens holding tube 31 on the lens mount 11 side, and the adjustment screw 23 is engaged with the groove surface of the V-groove 31b of the lens holding tube 31 on the lens mount 11 side, and is engaged with the groove surface on the lens mount 11 side. After adjusting the distribution of back focus at each focal length, the interlocking member 32 and the lens holding cylinder 31 are fixed. This adjustment work is performed before adjusting the flange back of the zoom lens barrel, and is for aligning the focusing positions on the long focal length side and the short focal length side, respectively.

(Problems to be solved by the invention) As shown in FIG. 4, when fixing the interlocking member 32 and the lens holding cylinder 31 after adjustment, the interlocking member
The adjustment screw 23 of No. 2 is inserted into the V groove 31 of the lens holding cylinder 31.
Since they engage with the groove surface on the lens mount 11 side of b, when a large external force P is applied to the tip of the zoom lens barrel, the interlocking member 32 receives the impact force P.
will be added. Therefore, due to this impact force P, the adjusting screw 23 and the V-groove 31b may be damaged, or the groove 31b may be dented by the adjusting screw 23. This had the disadvantage that backlash occurred in the optical axis direction, degrading optical performance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photographic lens barrel that solves the above-mentioned drawbacks and does not deteriorate optical performance even if an external impact force is applied to the tip of the lens barrel.

(Means for Solving the Problems) In the present invention, in order to obtain optical performance in a photographing lens barrel, the interlocking member 2 and the lens holding barrel 1 are
is adjusted by relatively moving in the optical axis direction, and after the adjustment, the adjustment screw 23 provided in the interlocking member 2 and the engagement groove 1b formed in the lens holding tube 1 are engaged to fix each other. The engagement portion between the adjustment screw 23 and the engagement groove 1b is formed by the groove surface of the engagement groove 1b on the focusing lens L1 side of the photographing lens barrel and the adjustment screw 23.

(Function) In the present invention, even if an impact force is applied to the tip of the photographic lens barrel, the portion engaged by the engagement groove 1b and the adjustment screw 23 is fixed to the front end of the photographic lens barrel. Since it is formed by the groove surface of the engagement groove on the casing lens side L1 and the adjustment screw, there is no possibility that the surface of the engagement groove 1b is dented by the adjustment screw 23 as in the conventional case.

(Example) Figures 1 to 3 show examples of the present invention, with Figure 1 showing a sectional view of a zoom lens barrel, and Figure 2 showing a partially enlarged sectional view of the above sectional view. , FIG. 3 shows a perspective view of the interlocking member and the lens holding cylinder.

This zoom lens barrel is constructed as already explained using FIG. 1. As shown in FIG. 3, the interlocking member 2 has three partial flange-like protrusions 2a formed on the inner peripheral side. This projection 2a is provided with a tap for a set screw 23. The first group lens holding cylinder 1 has three partial flange-like engaging portions 1c formed on the inner peripheral side. The clearance between the engaging portions 1c in the rotational direction is wider than the width of the protrusion 2a of the interlocking member 2 in the rotational direction. 1c and the protrusion 2a may be incorporated and mutually rotated. In addition, protrusion 2
The width A of a is the width B of the engaging portion 1c of the lens holding tube 1.
It's getting smaller. This results in the state shown in FIGS. 1 and 2.

As shown in FIG. 2, a V-groove 1b is formed in the lens holding tube 1, and when fixing the lens holding tube 1 and the interlocking member 2, an adjusting screw 23 is attached to the left end surface of the V-groove 1b in the figure. The tips of the two will come into contact and tighten. In that case, the protrusion 2 of the interlocking member 2
Since the projection 2a faces the engagement portion 1c of the lens holding tube 1 in the optical axis direction, even if, for example, an impact force P is applied to the interlocking member 2, this protrusion 2a
c to buffer this impact force P, and at that time, the adjusting screw 23 comes into contact with the left end surface of the V-groove 1b,
Since there is a gap between the adjustment screw 23 and the right end surface of the V-groove 1b, even if the interlocking member 2 moves to the right of the optical axis, the groove surface of the V-groove 1b will not be damaged.

Therefore, with such a structure, even when an impact force P is received from the tip of the lens barrel in the direction of the arrow, as shown in FIG.
Without applying any force to the abutting part (local abutting part) between the V-groove 1b of the lens holding barrel 1, There is no possibility that force is applied to the contact portion (where the contact portion is provided) and impressions are left on the abutting portion, thereby preventing deterioration of optical performance.

(Effects of the invention) As described above, according to the invention, even if an impact force is applied to the tip of the photographic lens barrel, the adjustment screw and the engagement groove are regulated by the engagement groove on the focusing lens side. Since this is done on the surface, there is no dent from the adjustment screw on the surface of the engagement groove as in conventional methods, which prevents play in the optical axis direction and does not degrade optical performance. .

According to this embodiment, the movement of the interlocking member and the lens holding cylinder in the optical axis direction is restricted by the projection 2a of the interlocking member 2 and the engagement portion 1c of the lens holding cylinder 1, so that the lens holding cylinder is resistant to impact from the tip of the lens barrel. Furthermore, since the lens holding cylinder 1 and the interlocking member 2 are connected by a bayonet type, the assembly is not inferior to that of the conventional one, and there is also an advantage that the back focus distribution adjustment work by the focusing lens can be easily performed.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, in which FIG. 1 is a vertical sectional view of a zoom lens barrel, and FIG.
This figure is a partially enlarged cross-sectional view of the above-mentioned cross-sectional view, and FIG. 3 is a perspective view of the lens holding cylinder 1 and the interlocking member 2. Fourth
The figure is a partially enlarged sectional view of the tip portion of a conventional zoom lens barrel. Explanation of symbols of main parts, 1...Lens holding tube,
DESCRIPTION OF SYMBOLS 1... Engagement part, 2... Interlocking member, 2a... Projection, 1b... V groove, 23... Adjustment screw.

Claims (1)

[Claims for Utility Model Registration] A focusing lens that is operated during focusing, a lens holding tube that has an engaging groove and holds the focusing lens, and an adjustment that engages with the engaging groove. an interlocking member that has a screw and rotates the lens holding tube in conjunction with the rotation of the focusing lens; and an interlocking member that rotates the lens holding tube in conjunction with the rotation of the focusing lens; and a support tube that supports the focusing lens so that it can be extended in the optical axis direction, and the engaging groove and the focusing lens are arranged so that the position of the focusing lens in the optical axis direction can be adjusted in order to obtain optical performance. The lens holding cylinder and the interlocking member are disengaged from each other by cutting off the engagement with the adjusting screw, the lens holding cylinder and the supporting cylinder are moved relative to each other via the helicoid screw, and the adjusting screw and the interlocking member are removed after adjustment. In a photographing lens barrel in which the lens holding barrel and the interlocking member are integrated by engaging a mating groove, the protrusion protrudes toward the inner circumferential side of the interlocking member and is provided with the adjustment screw; and a flange portion that protrudes toward the outer circumference of the lens holding cylinder and is provided closer to the lens mount than the position where the engagement groove is formed, and after the adjustment, the adjustment screw is engaged with the engagement groove. At this time, the screw surface of the adjustment screw engages with the groove surface of the engagement groove on the opposite side to the flange, and the engagement force causes the protrusion to abut against the flange, and the interlocking member and A photographing lens barrel characterized in that relative movement of the lens holding barrel in the optical axis direction is restricted.