JPH08313790A - Photographing lens unfolding device - Google Patents

Abstract

PURPOSE: To prevent an adverse influence from being exerted on focusing because an intermediate helicoid member is inadvertently turned when vibration or impact is given. CONSTITUTION: This photographing lens unfolding device is constituted of an inside helicoid member 8 holding a photographing lens 16 and freely moving in an optical axis direction, an outside helicoid member 5 arranged on the outside of the member 8 and fixed in a camera body, and the intermediate helicoid member 7 arranged between the members 8 and 5, helicoid-coupled with both of the members 8 and 5 and freely turned centering around an optical axis; and it is provided with a turning preventing means 20 preventing the turning of the member 7 when the member 7 is not operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic lens feeding device, and more particularly to a photographic lens feeding device provided with means for preventing rotation of an intermediate helicoid member in a so-called double helicoid type feeding device.

[0002]

2. Description of the Related Art Conventionally, a double helicoid system, that is, an inner helicoid member that holds a photographing lens and is movable in the optical axis direction, and an outer helicoid member that is arranged outside the inner helicoid member and is fixed to a camera body In the feeding device for the photographing lens, which is arranged between the inner helicoid member and the outer helicoid member and includes an intermediate helicoid member that is rotatable about the optical axis by helicoid coupling with both helicoid members, The outer helicoid member is fixed to a fixed object such as a camera body, and the inner helicoid member is restrained in the rotation direction by a linear guide member (for example, a key). Since the key is fixed to the camera body, the inner helicoid member has a degree of freedom only in the straight traveling direction. In the feeding device having such a configuration, when the intermediate helicoid member is driven and rotated by an arbitrary method, the intermediate helicoid member rotates due to the helicoid coupling with the outer helicoid member, and accordingly, the inner helicoid member rotates. Moves in the optical axis direction, and for example, a focus adjustment operation is performed.

[0003]

In the above-described conventional feeding device, the intermediate helicoid member is sandwiched between two members, the outer helicoid member and the inner helicoid member, but the helicoid members of the outer helicoid member and the inner helicoid member are different from each other. It is only held by a comparatively weak frictional force with the screw surface of, and is not restrained at all with respect to the camera body.
That is, it is in a state of floating between the outer and inner helicoid members.

Therefore, after the position of the inner helicoid member is determined to determine the lens position for the focus adjustment operation, that is, when the intermediate helicoid member is not operated, an unexpected accident such as vibration or impact is externally applied. When a force is applied, the intermediate helicoid rotates, and as a result, the inner helicoid member also moves in the optical axis direction, which may hinder focus adjustment.

In this case, when the focusing operation is performed by the TTL method by autofocus or manually, the movement amount of the lens can be detected through the lens, so that the movement amount of the lens can be corrected. If the lens system does not perform the focusing operation, such as a viewfinder camera, it cannot be detected even if the lens system moves, so it cannot be corrected, and as a result, out-of-focus photography may occur. There is.

In order to solve such a drawback, an electric detection member such as an encoder for detecting the movement of the helicoid is attached to the intermediate helicoid member, and means for detecting the lens position by the detection signal from the detection member is provided. That is, for example, Japanese Patent Application No. Sho 61-29195 filed by the present applicant.
No. 0 is proposed. However, in this case, the structure of the feeding device may be complicated, and the electric brush also vibrates when vibration or impact is applied, which makes it difficult to accurately detect the position.

Therefore, an object of the present invention is to provide a photographic lens feeding device having a simple structure in which the intermediate helicoid member does not move due to an external impact or the like even after the position of the lens system is determined, and the accurate position can be held. Is to provide.

[0008]

In order to achieve the above-mentioned object, the taking-lens feeding device of the present invention is an inner helicoid member (8) which holds the taking lens (16) and is movable in the optical axis direction. And an outer helicoid member (5) arranged outside the inner helicoid member and fixed to the camera body, and arranged between the inner helicoid member and the outer helicoid member and connecting both helicoid members with each other. In the device for feeding the photographing lens, which comprises an intermediate helicoid member (7) rotatable about the optical axis, a rotation blocking means for blocking the rotation of the intermediate helicoid member when the intermediate helicoid member is not operating ( Two
0, 40) is provided.

[0009]

With the above-mentioned structure, according to the feeding device of the present invention, since the rotation preventing means for preventing the rotation of the intermediate helicoid member is provided, the intermediate helicoid member is not operated. Does not rotate. Therefore, it is possible to prevent the inner helicoid member from moving in the optical axis direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same parts are designated by the same reference numerals.

FIG. 1 is a cross-sectional view of an essential part of a taking-out device for a photographing lens showing an embodiment of the present invention. The feeding device illustrated in FIG. 1 is provided with a position detecting device of a lens system, but it goes without saying that a feeding device without such a position detecting device may be used. The taking lens system, that is, the master lens 16 is the supporting member 1
It is fixedly supported by 9. A screw portion 19a is engraved on the outer peripheral surface of the support member 19, and is screwed into the screw portion 21a engraved on the inner peripheral surface of the annular cylindrical portion of the holding member 21. Therefore, the master lens 16 and the support member 19 are
Since the screw portion 19a and the screw portion 21a are screwed together, the screw member 19a and the screw member 21a are apparently integrated with respect to the holding member 21 in the optical axis direction. The holding member 21 is driven by a driving member 17 having a driving mechanism that drives the shutter and diaphragm 23 and further moves the master lens 16 in the optical axis direction for focusing. The holding member 21 is fixed to an annular flange portion 8d extending inward of the inner helicoid member 8.
The inner helicoid member 8 is a cylindrical member, and has a key hole 8b penetrating in the axial direction, a helicoid portion 8a, and an outer peripheral surface 8
c and a flange portion 8d.

A cylindrical intermediate helicoid member 7 is fitted radially outward of the inner helicoid member 8. The intermediate helicoid member 7 has a helicoid portion 7a on its inner peripheral surface, and this helicoid portion 7a meshes with the helicoid portion 8a. A helicoid portion 7b and a gear portion 7c are formed on the outer peripheral surface of the intermediate helicoid member 7, respectively. The intermediate helicoid member 7 is further provided with an annular flange portion 7 slightly protruding outward at an end portion closer to the subject in the optical axis direction.
d. Rotation preventing means, which will be described later, that is, elastic members 20 and 40 are fixed to the flange portion 7d so that one ends thereof come into contact with the outer peripheral surface 8c of the inner helicoid member 8.

A cylindrical outer helicoid member 5 is arranged outside the intermediate helicoid member 7. The inner peripheral surface of the outer helicoid member 5 is provided with a helicoid portion 5a that meshes with the helicoid portion 7b of the intermediate helicoid member 7. A part of the outer helicoid member 5 is fixed to a part 4 of a camera body (not shown) by screws 6. A straight advance key 13 is fixed to one end of the outer helicoid member 5 in the optical axis direction. Therefore, the straight-ahead key 13 is also fixed to the camera body. The key portion 13a of the straight advance key 13 is inserted into the key hole 8b of the inner helicoid member 8. Therefore, the inner helicoid member 8 is not rotatable because the key portion 13a and the key hole 8a are engaged with each other, and is movable only in the optical axis direction. The gear portion 7c of the intermediate helicoid member 7 is
The reduction gear 3 is rotatably supported by a part 4 of the camera body, and the reduction gear 3 is further meshed with a gear 2 fixed to a motor 1 provided in the camera body. . Therefore, when the motor 1 is driven, the intermediate helicoid member 7 rotates about the optical axis via the gear 2, the reduction gear 3, and the gear portion 7c. Since the intermediate helicoid member 7 is helicoidally coupled to the outer helicoid member 5 and the inner helicoid member 8, when the intermediate helicoid member 7 rotates, the inner helicoid member 8 moves to a predetermined position in the optical axis direction. Become. As a result, the master lens 16 moves in the optical axis direction.

An encoder 11 is provided on the outer peripheral surface of the intermediate helicoid member 7, and a plurality of brushes 10 fixed to a brush base 9 are arranged in contact with the encoder 11. It should be noted that the above-mentioned feeding device is arranged almost entirely inside the cover 12, reference numeral 18 is a lens barrier for protecting the master lens 16, and 14 is a conversion lens system. ing.

Next, referring to FIG. 2, details of the rotation preventing means of the present invention, that is, the elastic member 20, will be described. The elastic member 20 having a predetermined friction coefficient and elasticity has a ring-shaped overall structure, and has an annular lip portion 20a that makes frictional contact with the outer peripheral surface 8c of the inner helicoid member 8, and extends in the optical axis direction. And inner and outer wall portions 20c and 20b of the. A metal frame 22 is arranged in an annular space defined between the inner and outer wall portions. In the case of this embodiment, the elastic member 20 and the metal frame 22 are integrally molded and are in close contact with each other. Since the elastic member 20 is manufactured from, for example, silicon rubber or the like, the end surface 7e of the intermediate helicoid member 7 is formed.
Since it is difficult to bond to, it is bonded via the metal frame 22. Furthermore, since the metal frame 22 well holds the ring-shaped shape of the elastic member 20, the workability of bonding is improved. With this configuration, the lip portion 20a of the elastic member comes into contact with the outer peripheral surface 8c of the inner helicoid member 8 to prevent the intermediate helicoid member 7 from floating, and to prevent the intermediate helicoid member 7 and the inner helicoid member 8 from floating. Even if the intermediate helicoid member 7 tries to rotate due to a shock or the like during non-operation due to an appropriate friction between and, the frictional force becomes a sufficient stopping force, so that the intermediate helicoid member 7 cannot be rotated because it is held at the same position. Therefore, the inner helicoid member 8 does not move in the axial direction and does not hinder the focus adjustment.

A second embodiment of the elastic member will be described with reference to FIG. According to this embodiment, the metal frame 22 is unnecessary. The elastic member 40 comprises a first portion 30 and a second portion 31 each made of rubber or plastic. The first portion 30 has an annular lip portion 30a that comes into frictional contact with the outer peripheral surface 8c of the licoid member 8, and the second portion 31 has a cylindrical portion 31 that extends in the optical axis direction.
It has a and an annular hook portion 31b. Further, since the first portion 30 and the second portion 31 are attached to each other at the attaching portion 32, they are practically one piece. Of course, it can be made as one piece from the beginning. In this case, since the hook portion 31b is caught by the step portion 7f of the flange portion 7d of the intermediate helicoid member 7 while having an elastic force, the elastic member 40 is well held by the intermediate helicoid member 7. Therefore, the adhesiveness of the elastic member 40 does not matter so much. Therefore, the intermediate helicoid member 7
The elastic member 40 can be easily attached and fixed to and.

In the above-mentioned two embodiments, the lip portions 20a and 30a of the elastic members 20 and 40 are provided annularly and continuously over the entire circumference. However, this is not necessarily the entire circumference, but the circumference is not limited to the circumference. You may make it provide an appropriate space | interval. In that case, the intervals may be equal or unequal. Furthermore, if the pressing force is not biased or the balance of the intermediate helicoid member 7 is not disturbed, it may be provided only in a part of the circumferential direction.

[0018]

The following effects can be obtained by the drawing lens feeding device of the present invention described in detail above.

Since the rotation preventing means having a simple structure prevents the rotation of the intermediate helicoid member when the intermediate helicoid member is not operating, the intermediate helicoid member inadvertently rotates at the time of vibration or impact to adversely affect the focus adjustment. Prevent giving.

Further, as an effect of the embodiment, since the intermediate helicoid member is pressed uniformly in the radial direction when the lip portions are provided on the entire circumference or at predetermined uniform intervals, the eccentricity and the piece due to the combination of the helicoids can be obtained. It can prevent leaning.
Further, when the lip portion is provided over the entire circumference, the helicoid portion is shielded from the outside, so that foreign matter such as dust or dust can be prevented from entering the gap between the helicoid portion and hindering the operation of the helicoid.

[Brief description of drawings]

FIG. 1 is a sectional view of a feeding device showing an embodiment of the present invention.

FIG. 2 is a diagram showing details of an elastic member in FIG.

FIG. 3 is a view showing another embodiment of the elastic member.

[Explanation of symbols]

 5 ... Outer helicoid member 7 ... Intermediate helicoid member 8 ... Inner helicoid member 16 ... Master lens 20, 40 ... Elastic member

[Procedure amendment]

[Submission date] July 31, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Conventionally, a double helicoid system, that is, an inner helicoid member that holds a photographing lens and is movable in the optical axis direction, and an outer helicoid member that is arranged outside the inner helicoid member and is fixed to a camera body And an intermediate helicoid member that is disposed between the inner helicoid member and the outer helicoid member and is rotatable about the optical axis by being helicoidally coupled with both helicoid members. . In order to extend this photographing lens, a circumferential gear to which a driving force is transmitted is provided on the intermediate helicoid member. The circumferential gear moves the intermediate helicoid member in the optical axis direction by transmitting the driving amount from the motor. The circumferential gear also moves in the optical axis direction according to the movement of the intermediate helicoid member.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

When a circumferential gear is provided on the entire surface of the intermediate helicoid member in order to secure the amount of movement of the intermediate helicoid member, when the photographing lens is in a protruding state,
Since the intermediate helicoid member also projects outside the camera body, it is necessary to provide a protective cylinder so as to cover and protect this gear. However, by providing the protective cylinder, the diameter of the lens barrel increases by the thickness of this cylinder. Therefore, an object of the present invention is to provide a taking-lens take-out device capable of increasing the take-out of a lens barrel and contributing to downsizing of a camera.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

In order to achieve the above-mentioned object, an apparatus for feeding a photographing lens according to the present invention is provided with an inner helicoid member (8) which holds a photographing lens (16) and is movable in the optical axis direction, and the inner helicoid member. An outer helicoid member (5) arranged outside and fixed to the camera body, and arranged between the inner helicoid member and the outer helicoid member and helicoid-coupled with both helicoid members to center the optical axis. In a device for feeding a photographing lens, which comprises a rotatable intermediate helicoid member (7), a drive motor (1) and a circumferential gear formed on the outer periphery of the intermediate helicoid member with a first width in the optical axis direction. (7
c), the rotation axis is parallel to the optical axis, and the width in the optical axis direction is formed to be a second width longer than the first width. The second gear meshes with the circumferential gear to generate the driving force of the drive motor. And a transmission gear (3) for transmitting to the circumferential gear.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

With the above-described structure, according to the taking-out device for the taking lens of the present invention, the circumferential gear formed on the outer circumference of the intermediate helicoid member with the first width in the optical axis direction, and the rotary shaft. Is formed with a second width that is parallel to the optical axis and has a width in the optical axis direction that is longer than the first width, and meshes with the circumferential gear to transmit the driving force of the drive motor to the circumferential gear. Since the transmission gear is provided, it is possible to always transmit the drive amount while ensuring the movement amount of the intermediate helicoid member. That is, since the width of the transmission gear is made longer than the width of the circumferential gear,
Even if the circumferential gear moves in the optical axis direction, the meshing of the transmission gear and the circumferential gear is always ensured, and the driving force is transmitted. Further, since the circumferential gear can be provided with a relatively narrow width, it is possible to arrange the position detection device and the like by utilizing the space on the intermediate helicoid member other than the circumferential gear.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

[0018]

As described above, according to the feeding device of the photographing lens of the present invention, the circumferential gear formed on the outer circumference of the intermediate helicoid member with the first width in the optical axis direction, and the rotation axis is the optical axis. A transmission gear that is formed in a second width that is parallel to and has a width in the optical axis direction that is longer than the first width, and that meshes with the circumferential gear and transmits the driving force of the drive motor to the circumferential gear. Since the above is provided, it is possible to always transmit the driving amount while securing the moving amount of the intermediate helicoid member. That is, since the width of the transmission gear is made larger than the width of the circumferential gear, even if the circumferential gear moves in the optical axis direction, the engagement between the transmission gear and the circumferential gear is always ensured and the driving force is transmitted. Further, since the circumferential gear can be provided with a relatively narrow width, it is possible to arrange the position detection device and the like by utilizing the space on the intermediate helicoid member other than the circumferential gear.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Daiki Tsukahara 1-6-3 Nishioi, Shinagawa-ku, Tokyo Inside Nikon Oi Manufacturing Co., Ltd. (72) Inventor Kiyosada Machida 1-6-3 Nishioi, Shinagawa-ku, Tokyo No. Stock Company Nikon Oi Works

Claims (2)

[Claims] 1. An inner helicoid member that holds a photographing lens and is movable in the optical axis direction, an outer helicoid member that is arranged outside the inner helicoid member and is fixed to a camera body, and the inner helicoid member. In a feeding device for a photographing lens, which is arranged between an outer helicoid member and comprises an intermediate helicoid member that is rotatable about an optical axis by being helicoid-coupled with both helicoid members, when the intermediate helicoid member is not operating, A taking-out device for a photographing lens, characterized in that a rotation preventing means for preventing rotation of the intermediate helicoid member is provided. 2. The rotation preventing means is an elastic member having a member provided at the tip of the intermediate helicoid member and in contact with the inner helicoid member. Of the taking lens of the.