JPS6210748Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an interchangeable lens, and more particularly to a support structure for a signal member that rotates around the optical axis of the interchangeable lens.

Conventionally, as a support structure for a signal member, a structure in which balls are arranged around the entire circumference of an annular portion of the signal member is known. However, the interchangeable lens having this structure has problems such as the generation of noise when the balls collide with each other and the cost reduction being difficult.

In addition, the structure shown in FIGS. 1a and 1b in which the ball is not arranged around the entire circumference of the annular portion is also known, but this structure does not have enough margin for the dimensions of each member in the radial direction of the interchangeable lens, and the lens performance and However, this method has problems such as hindering the miniaturization of lenses.

Next, a conventional interchangeable lens support structure will be described.

Figures 1a and 1b show the main parts of a conventionally used support structure for a signal member. In the figure, reference numeral 1 denotes a signal member that is fitted on the inner or outer periphery of the fixed barrel of the lens barrel and has a circular ring part 1a in part, and the signal member is inserted back and forth from the circular ring part along the optical axis. arm part 1
b, 1c extend, one end of which is configured to be interlocked with an aperture device or an aperture preset device in the lens barrel (not shown), and the other end extends to protrude from the lens barrel in the camera mounting direction, and is connected to the camera side (not shown). Arranged so as to be interlockable with the interlocking member. The annular portion 1 of the signal member 1
A groove 1 having a V-shaped cross section or a semicircular shape is provided on the outer peripheral surface of a.
a′ is formed. The ball 2 is attached to the tapered surface 4a of the fixing member 4 of the lens barrel, the groove 1a' of the annular portion of the signal member, and the holding member 6 that holds the ball 2.
The retainer 8 (bearing ball holding member) as shown in the figure is further arranged in the space formed by the retainer 8, and the retainer 8 has holes 8a ₁ , 8a ₂ . . . into which the balls 2 are fitted. They are formed in arbitrary locations at equal intervals.

In the above structure, the retainer 8 has a width 8b in the radial direction of the optical axis. Therefore, the retainer 8 requires a required inner diameter and outer diameter. That is, the radial dimensions 8c ₁ and _8c 2 of the hole 8a ₁ of the retainer 8 into which the balls enter (see Fig. 1b)
Therefore, the effective aperture of the lens optical system becomes smaller due to the 8c ₁ dimension, and the outer diameter of the lens barrel must be increased due to the 8c ₂ dimension. Ta. In the retainer 8, the balls 2 are fitted into the holes 8a ₁ , 8a ₂ . At the same time, the retainer 8 itself also rotates around the optical axis.
Therefore, the outer peripheral end of the retainer 8 and the groove 1
A gap with the bottom surface of a' and a gap A in the direction of the outer diameter of the lens barrel are required, resulting in a problem that the effective aperture of the lens optical system becomes smaller and the outer diameter of the lens barrel becomes larger. Furthermore, the above-mentioned retainers have conventionally been made of expensive metal materials such as phosphor bronze and brass, making it difficult to reduce the cost of the product. Furthermore, the bearing shown in FIG. 1 has a structure that makes it difficult to automatically assemble the lens barrel. That is, in the above structure, after fitting the annular portion of the signal member into the fixing member 4 of the lens barrel, the retainer 8 is inserted into the space formed by the tapered surface, the tapered side surface of the groove, etc., and the hole 8a of the retainer 8 is inserted. _1,8
It has a step of fitting the ball 2 into a ₂ ..., and then fixing and assembling the ball holding member 6.

In this process, it has been difficult to automatically mechanize the work of inserting the retainer 8 and placing the balls 2 in the holes 8a ₁ , 8a _{2 .} . . of the retainer 8.

Furthermore, a bearing having a structure in which the annular retainer 8 described above is arranged perpendicularly to the optical axis has the aforementioned dimensions A, 8c ₁ , 8
Due to constraints such as _c2 , it is difficult to provide a large optical path aperture for an interchangeable lens, which poses a problem in obtaining a brighter interchangeable lens.

This invention was proposed with the aim of solving the problems of the conventional support structure described above, and by increasing the optical path opening of the lens barrel, which affects the brightness of interchangeable lenses, The objective is to obtain a brighter interchangeable lens using an optical system. In order to reduce the cost of the lens barrel, a structure for holding the ball at a predetermined position around the optical axis is adopted instead of the retainer 8, and a suitable support structure is provided for this purpose.

Furthermore, the present invention shortens the lens length even if two signal members are provided that are rotatably supported around the optical axis.
The purpose is to provide an interchangeable lens that can be made smaller.

The present invention will be described in detail below with reference to Examples.

FIG. 2 shows an example of an interchangeable lens to which the bearing structure of the present invention is applied.
Reference numeral 10 indicates a lens barrel body formed in a ring shape and having a threaded engagement surface for distance adjustment on the inner surface of the tip thereof; Reference numeral 12 indicates a distance adjustment ring; the ring is an intermediate helicoid that meshes with the threaded engagement surface of the barrel body 10; It is provided integrally with the ring 12'. Reference numeral 13 denotes a movable inner cylinder that supports an optical member, and a helicoid surface is formed on the outer periphery of the movable inner cylinder, which meshes with the inner helicoid of the helicoid ring 12'. Reference numeral 14 indicates a bayonet mount retaining ring integrally fixed to the rear end of the lens barrel body 10, and an engraved portion 14a is provided on the outer circumference of the ring to indicate a reference mounting position when mounted. ing. Reference numeral 15 denotes an aperture preset ring rotatably fitted into a concave ring formed between the lens barrel body 10 and the retaining ring 14, and 16 a bayonet fitted into the rear opening step of the retaining ring 14. This member performs a tightening operation against a camera-side bayonet pawl when a lens is attached to a camera body, which will be described later. The bayonet member 16 is secured by a screw 17 screwed onto the retaining ring 14.
It is integrally fixed to the retaining ring 14. Reference numeral 18 denotes a mount member, which is rotatably fitted into a concave ring between the retaining ring 14 and the bayonet member 16, and whose rear part is formed into a cylindrical shape and has a reference fitting diameter portion 18a. A back cover member 19 having an optical axis opening is fitted and fixed with screws (not shown). Reference numeral 20 designates a positioning pin set up on the mount reference position surface of the mount member 18, and is fitted into a position regulating slit formed in the camera side bayonet portion to lock the mount member 18. Reference numeral 21a is a linking member for transmitting a preset aperture signal, and the mount member 18 is designed to transmit the aperture signal from the linking member on the camera side when shooting in automatic aperture adjustment mode, and to the linking member on the camera side when shooting in manual aperture adjustment mode. They are each integrally formed with a ring 21 (not shown) which is rotatably arranged. Reference numeral 22a designates an automatic aperture drive lever, each lever protruding through a notch provided in the back cover member 19, and integrated with an automatic aperture ring 22 (not shown) rotatably disposed within the mount member 18. is formed.

The mounting mechanism of the interchangeable lens shown in FIG. 2 and the interlocking mechanism with the diaphragm device are explained in Japanese Patent Application No. 44247 of 1972, filed on April 18, 1978, so their explanation will be omitted here.

3 to 5 show the main parts of the support structure for the ring 21 and the automatic diaphragm member 22. As shown in FIG. The mount member 18 has a first protrusion 18b and a second protrusion 18c in the inner diameter direction thereof.
Arc-shaped notches 18d and 18e between the
is formed. 18f is an opening for the optical path. The back cover member 19 is attached to the first portion of the mount member 18.
The outer cylindrical portion 19a has a U-shaped cross section to be fitted between the protruding portion 18b and the second protruding portion 18c.
and an inner cylindrical portion 19b, and arcuate notches 19c, 19 through which the interlocking member 21a and the lever 22a pass.
d is provided.

The interlocking member ring 21 has a V-shaped or semicircular groove 21b formed on the outer periphery of the annular portion thereof.
The ring 22 of the automatic aperture lever has a groove 22b formed on the inner circumferential surface of the annular portion thereof.

In the description of the embodiments of the present invention, a case where the invention is applied to an interchangeable lens with a new mechanism shown in FIG. 2 is shown.

When installing this interchangeable lens on the camera, use the positioning pin 2.
0 into the aforementioned slit of the camera (not shown), align the lens-camera coupling member (bayonet ring, etc.), and hold the lens barrel main body 10, aperture ring 15, etc. on the distance ring of the lens barrel. By operating the lens barrel, the lens barrel side rotates relative to the mount member and the back cover member, and the attachment and connection are performed.

When aligning the positioning pin 20 and the slit, the automatic diaphragm lever 22a on the lens side maintains a non-rotating interlocking relationship with an interlocking member on the camera side (not shown).

The outer cylindrical portion 19a and the inner cylindrical portion 19b of the back cover member 19 are provided with holes 19 in the radial direction of the optical axis, as shown in FIG.
e ₁ , 19e ₂ . . . are provided at approximately equal intervals (for example, five locations) around the optical axis, and the holes 19e ₁ , 19e ₂ .
... have stepped portions 19e ₁ ′, 19e ₂ ′, . . . . Similarly, a hole 19 is formed in the inner cylindrical portion 19b.
f ₁ , 19f _{2 .} . . and stepped portions 19f ₁ ′, 19f ₂ ′ (not shown). 23 is the hole 19e ₁ , 1
9e ₂ ..., 19f ₁ , 19f ₂ ... are ball holding members that hold the bearing balls 2. The holding member 23 is attached to the stepped portions 19e ₁ ′, 19 of the hole.
e ₂ '..., 19f ₁ ', 19f ₂ '..., and determines the position of the ball holding member in the radial direction of the lens optical axis; and a shaft portion 23d that fits and holds the ball holding member in the hole 19e ₁ . A hemispherical depression 23b for holding the ball 2 is provided on the tip surface of the shaft. Furthermore, a plurality of projections 23c ₁ , 23c _{2 .} . . are provided on the surface of the collar portion of the ball holding member. ring 2
1 and 22, each arm penetrates each of the above-mentioned notches, and the back cover member 1
The outer circumferential groove 21b and inner circumferential groove 22b of the rings 21 and 22 are arranged in a multilayered manner in the space formed by the outer and inner cylindrical parts 19a and 19b of the rings 21 and 22.
A ball 2 is placed so as to be sandwiched between the tapered side walls of the back cover member 19.
By inserting the ball holding member 23 into e ₁ , 19e _{2 . . .} , 19f ₁ , 19f 2 . This will cause ring 2
1 and 22 are rotatably supported by the back cover member 19.

When the ball holding member 23 is inserted, the flange 23a of the ball holding member 23 sinks into the stepped portion 19e ₁ ′..., and the protrusion 23c of the ball holding member 23 sinks into the outer diameter cylindrical portion 19a of the back cover member 19. Slightly exposed from the outer diameter surface.

Also, attach the ring 22 of the automatic aperture lever to the back cover member 1.
When inserting the ball holding member 23 from the optical path opening side into the holes 19f ₁ , 19f ₂ . Projection 2 of ball holding member 23
3c is slightly exposed. From this state, back cover member 1
The outer and inner cylindrical portions 19a and 19b of 9 are connected to the first and second protruding portions 18 of the mount member 18.
Fits between b and 18c. By this fitting, the exposed portion of the projection 23c of the ball holding member 23 is crushed by the projections 18b, 18c of the mount member 18, and the ball holding member 23 is inserted into the holes 19e ₁ , 19e ₂ . . . of the back cover member 19. , 19f ₁ , 19f _{2 .} . . , and maintains close contact when the back cover member 19 and the mount member 18 are fitted together.

The mount member 18 and the back cover member 19 are fixed with screws 24.

Incidentally, as understood from the illustration, the interlocking member 21a
A ball holding member 23 is inserted from the outside (in the direction of arrow B) of the outer cylindrical portion 19a of the back cover member 19, and holds the ball of the ring 22 of the automatic aperture lever 22a. 23 is the inner cylindrical part 19 of the back cover member 19
It is inserted from inside b (opening for optical path, direction of arrow c).

As described above, the signal members 21a and 22a of the present invention
As shown in FIG.
The annular parts 21 and 22 are stacked in multiple layers,
The balls 2 placed in the grooves 21b and 22b of the annular portion are connected to the tip recess 23b of the ball holding member 23 and the grooves 21b and 2.
It is rotatably held between 2b. As a result, the signal members 21a and 22a protrude and extend from the arcuate notches 19c and 19d of the back cover member 19, and are supported so as to be rotatable at a constant rotation angle. By fitting and screwing between the protruding part 18b and the second protruding part 18c, each signal member 21a, 22a penetrates the arcuate notch 19c, 19d of the back cover member and extends in the camera mounting direction (not shown). It can be extended and rotated within a predetermined rotation range.

As described above, the embodiment of the present invention includes the preset aperture signal transmission interlocking member 21a and the automatic aperture lever 22.
Grooves 21b, 22b in which the ball 2 rotates are formed on the outer peripheral surface and inner peripheral surface of the annular parts 21, 22 (rings) of a, forming a part of an interchangeable lens, and the annular parts 21b, 22b of the signal member. 22b, and a back cover member 19 having a portion 19a (or 19b) partially overlapping along the optical axis direction, and the overlapping portion 1 of the member 19 is
_{A ball} holding member 23 that has holes 19e ₁ , 19e ₂ . By inserting the ball 2, the ball is held at a fixed position around the optical axis, and each signal member 21a, 22b is connected to the back cover member 19 via the ball 2.
is rotatably supported around the optical axis at the heavy portion. The tips of the signal members 21a and 22b penetrate through the notches 18d and 18e and are configured to be able to interlock with an aperture device and a preset device (not shown), and rotate in response to the set aperture value of an aperture preset ring (not shown). Configure as possible.

In the explanation of FIGS. 2 to 5 of this embodiment, the interchangeable lens of the new mechanism shown in the aforementioned Japanese Patent Application No. 44247 of 1972 (Japanese Patent Publication No. 60-41334) previously filed by the applicant will be used as an example. However, the present invention eliminates the need to select the form of the mount mechanism and the aperture interlocking mechanism, and is suitable for supporting many of the signal members that rotate around the optical axis and exchange signals between the interchangeable lens and the camera during shooting. The great effect of the present invention is that it can be applied.

Furthermore, for example, the bearing balls used in interchangeable lenses for 35mm single-lens reflex cameras have a diameter of 1 mm.
It is preferable to set the diameter of each part of the ball holding member 23 of the present invention to be approximately 1.5 mm, taking into consideration the outer diameter of the lens barrel, the effective aperture of the lens optical system, and supporting performance. It is determined by the size of the depression 23b, that is, the outer diameter of the ball. The dimensions of each part of the ball holding member 23 are determined in units of several millimeters based on the diameter of the ball, and by making the ball holding member 23 from a plastic material (especially thermoplastic resin is preferred), material costs are reduced. was able to be significantly reduced.

In the embodiment of the present invention, the material of the bearing balls 2 is of course steel balls conventionally generally used for bearings, but even if made of hard plastic materials, they can withstand use. be.

As described above, in the support structure of the present invention, the effective aperture 19h of the lens can be increased by several millimeters (more than 2.6 mm in the example) compared to the conventional retainer type structure, thereby increasing the brightness of the interchangeable lens. I was able to make the lens even brighter.

That is, in FIGS. 3 and 5, the wall thickness of the first and second protrusions 19a and 19b of the back cover member can be made thinner by 2.6 mm or more in the embodiment, and as a result, the thickness of the back cover member 19 can be reduced by 2.6 mm or more. The inner diameter of the optical path aperture could be increased.

In addition, in the present invention, since the annular portions serving as the rotatable support portions of the two signal members are arranged at positions overlapping in the radial direction in the lens barrel, the lens barrel itself does not become particularly long.

[Brief explanation of drawings]

FIG. 1 shows the main part of a support structure for a signal member of a conventional interchangeable lens, and FIG. 1a shows the relationship between the signal member and a retainer that holds a bearing ball. 1st
FIG. b is a cross-sectional view of the main part of the support portion of the lens barrel. Second
The figure is a partial axial cross-sectional view showing the overall concept of an interchangeable lens using the support structure of the present invention. FIG. 3 shows an exploded perspective view of the main parts of the support structure of the present invention, and in the figure, the optical axis o 1 - o ₂ of the interchangeable lens is shown to clarify the structure of each member that pivotally supports the signal members _21a and 22a. The mount member 18 and the back cover member 19 are shown as being bent. Therefore, the optical axis o ₁ −o ₂
and o ₁ ′−o ₂ ′ are displayed by bending the optical axis that is on a straight line. Figure 4 shows one of the signal members.
A developed view of essential parts showing an example in which a book (an interlocking member for transmitting a preset aperture signal) is pivotally supported on a back cover member 19 is shown.
FIG. 5 shows signal members (preset aperture signal transmission interlocking member 21a and automatic aperture member 22) according to the present invention.
A sectional view of the main part of the bearing portion when the lens (a) is pivotally supported within the interchangeable lens is shown. 18...Mount member, 19...Back cover member, 2
1a and 22a indicate signal members of the interchangeable lens 21
a is a preset aperture signal transmission interlocking member, 22a
23 is an automatic drawing member, and 23 is a ball holding member that holds a bearing ball.

Claims (1)

[Claims for Utility Model Registration] A structure for supporting two signal members arranged in the lens barrel so as to be rotatable around the optical axis and for transmitting information between the lens barrel and the camera. , a first cylindrical portion extending in the optical axis direction and a second cylindrical portion having a smaller diameter than the first cylindrical portion and overlapping in the radial direction are formed in the member constituting the lens barrel;
The first annular portion of the signal member is set to be smaller than the inner diameter of the first cylindrical portion and larger than the outer diameter of the second cylindrical portion, and is placed at a position overlapping the first cylindrical portion in the radial direction, and A second annular portion of the second signal member is set to have a larger outer diameter than the second cylindrical portion and a smaller diameter than the first annular portion, and is arranged at a position overlapping the second cylindrical portion in the radial direction. , further forming a circumferential groove on the outer peripheral surface of the first annular portion;
A circumferential groove is formed on the inner circumferential surface of the second annular portion, and a plurality of radial through holes are provided in each of the first and second cylindrical portions, and a shaft portion and a tip end of the shaft portion are provided with a plurality of radial through holes. A ball holding member having a recess is inserted into the through hole of the first cylindrical portion from the outer diameter direction so that the tip of the shaft portion faces the groove of the first annular portion, and the ball holding member has a recess. In the through hole, the shaft portion is inserted from the inner diameter direction so that the tip of the shaft portion faces the groove portion of the second annular portion, and the ball holding portion is further inserted between the groove portion of the first annular portion and the first cylindrical portion. A bearing ball is disposed between the groove of the second annular portion and the second annular member.
A support for a signal member of an interchangeable lens, characterized in that a bearing ball is disposed between the ball holding member of the cylindrical portion to support the first and second signal members rotatably around the optical axis. structure.