JP2864363B2 - Lens barrel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel, and more particularly to a lens barrel for moving an optical system, such as a zoom lens or a macro lens, using guide pins and cam grooves provided on a lens frame.

[0002]

2. Description of the Related Art A lens barrel is always inadvertently dropped or placed on another object even when it is attached to a camera body or when it is separated from the camera body such as a single-lens reflex camera. There is a risk of impact due to collision. In such a case, the movement of the photographing lens is performed by the guide pin and the cam groove. In the lenses of the present invention, the guide pin falls down due to an impact,
The subsequent smooth operation may not be possible due to the deformation of the cam groove.

Hereinafter, such a state will be described with reference to the drawings. FIG. 5 is a schematic cross-sectional view showing a conventional lens barrel for moving an optical system using a guide pin and a cam groove, and FIG. 6 is an enlarged cross-sectional view of a guide pin and a cam groove as a part thereof. is there. FIG. 7 is a plan view schematically showing a guide pin and a cam groove.

In FIG. 5, reference numeral 1 denotes a fixing ring, on the periphery of which a long groove 1a is provided in the optical axis direction as shown in FIG. Although not shown, there are two long grooves 1a for the front group lens moving frame 2 and the rear group lens moving frame 5. 3 is a front group lens frame, 4 is a front group lens, 5 is a rear group lens moving frame,
Reference numeral 6 denotes a rear lens group frame, and reference numeral 7 denotes a rear lens group. 8 is a cam frame, a cam groove 8a is formed as shown in Figure 7 on its periphery. Although not shown, there are also two cam grooves 8a for the front group lens moving frame 2 and the rear group lens moving frame 5. Reference numeral 9 denotes a guide pin of the front group lens moving frame 2, and 10 denotes a guide pin of the rear group lens moving frame 5, which is engaged with the respective lens moving frames 2, 5 with the long groove 1a and the cam groove 8a. Screwed.

[0005] A zoom ring 11 is screwed to the cam frame 8 by a set screw 12. Reference numeral 13 denotes a cam frame support ring which is attached to the fixed ring 1 by a screw portion 13a, and is supported so that the cam frame 8 can rotate on the fixed ring 1. With the above configuration, when the zoom ring 11 is rotated, the front lens group moving frame 2 and the rear lens group moving frame 5 are moved through the guide groove 9 and the long groove 1 a on the fixed ring 1 and the cam frame 8. Cam groove 8a
To move along the inner circumference of the fixed ring 1 in the direction of the optical axis of the photographing lens, so that an arbitrary focal length can be obtained.

In FIG. 6, when a force is applied in the direction of the arrow, that is, from the front lens frame 3 side, the guide pin 9
A force is directly applied to the arrow A portion of FIG. 7 and the side surface 8b of the cam groove 8a of the cam frame 8. If this force is a strong impact force due to a camera drop or the like, the guide pin 9 falls down or the cam groove 8a of the cam frame 8 is deformed, so that smooth operation becomes impossible thereafter.

In order to solve such a problem, Japanese Patent Publication No. 59-29842 discloses a guide collar made of an elastic body having a diameter slightly larger than the outer diameter of the guide pin at a part of the guide pin. By engaging the guide collar with the cam groove so that the deformation of the cam groove in the event of an impact does not affect the subsequent operation;
In the above structure, a method has been proposed in which the cross-sectional shape of the cam groove is made two steps, and only the guide collar is engaged with the guide surface of the cam groove so that the cam groove is not deformed.

[0008]

However, this method is
Guide collar requires moderate hardness, such as nylon, not completely absorb the shock for a Delrin or the like, to generate a gap between the cam grooves cause permanent deformation in Tsu good <br/> when, may not be secured positional accuracy of the shadow lens shooting, also fall down due connexion guide pin itself impact, but are likely to interfere with subsequent operation. The invention is suitable for use in
May cause heavy rotation of the cam frame or unnecessary wear.
While minimizing the impact on the lens barrel, even if the lens barrel is subjected to a shock greater than a predetermined value, especially in the optical axis direction, reduce the direct impact on the guide pins and cam grooves or minimize the fall of the guide pins. It is an object of the present invention to provide a lens barrel capable of performing a smooth and accurate operation.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a lens barrel for moving an optical system by sliding a guide pin and a cam groove with respect to each other. A moving frame that moves in the optical axis direction, a positioning member fixed to the moving frame ,
An optical axis on the outer periphery of the moving frame in front of the positioning member.
A first auxiliary member which is movable in the direction, the transfer
The first auxiliary member is provided between a moving frame and the first auxiliary member so as to press the first auxiliary member against the rear positioning member.
A second auxiliary member made of one or more elastic bodies to be urged, a cam groove having a fixed width formed in the cam frame, and a fixing rib;
In the state where each is engaged with the long groove formed in the
A guide pin fixed on the first auxiliary member, and when a predetermined or more shocking external force is applied to the moving frame from the front , the external force is absorbed by a second auxiliary member made of the elastic body. The present invention is characterized in that a direct impact on the guide pin and the cam groove can be reduced.

According to another aspect of the present invention, there is provided a lens barrel for moving an optical system by sliding a guide pin and a cam groove with respect to each other. Moving frame to move
When a positioning member fixed to the moving frame, the moving
Move to the outer periphery in front of the positioning member on the frame in the optical axis direction.
Movably provided, the front end of which is in contact with the moving frame and
And an auxiliary member having an elastic portion on the front side for urging the pressing member against the rear positioning member, and a cam frame.
Into the fixed width cam groove and the long groove formed in the fixed ring.
A guide pin fixed on the auxiliary member in the engaged state, and when a predetermined or more shocking external force is applied to the moving frame from the front , the external force is applied by the elastic portion of the auxiliary member. It is characterized in that it is configured to be able to absorb and directly reduce the impact on the guide pin and the cam groove.

[0011]

The lens barrel according to the present invention comprises a fixing ring having a long groove in the optical axis direction for moving the photographing lens, and a cam having a cam groove extending in the optical axis direction and the circumferential direction for moving the photographing lens. frame, between the long groove and the cam groove to engage the imaging lens moving frame and bisecting the auxiliary member the front group moving frame and <br/> auxiliary member lens moving frame guide pin is fixed to perform the movement of An elastic member is provided on the auxiliary member , and the guide pin is fixed on the auxiliary member . Yo
More specifically, a positioning member is fixed on the moving frame.
And the first auxiliary member is movable in the optical axis direction in front of it.
The first auxiliary member is provided between the moving frame and the first auxiliary member.
A second auxiliary member made of an elastic body provided provides
Is configured to be pressed against the positioning member
You.

Therefore, in actual movement of the lens, the rotation of the zoom ring or distance ring is transmitted to the cam frame, and the cam frame is engaged with the cam groove having a fixed width and the long groove of the fixed ring. wherein the guide pins and the guide pin is fixed first auxiliary member is moved in the optical axis direction, that this amount of movement is performed by transmitted before KiUtsuri dynamic frame via the elastic body Become. this
At this time, the first auxiliary member provided with the guide pin is positioned
Second auxiliary part having an elastic body on the same moving frame on the member side
It is pressed during normal use because it is pressed by the material
The spring force of the elastic body changes depending on the rotational position of the cam frame.
The acting force between the guide pin and the cam surface of the cam frame does not change.
Does not change. However, if the camera or lens
In particular, when a force exceeding a predetermined amount is applied to the moving frame,
The force applied to the frame is a second auxiliary member provided on the moving frame.
Through the first auxiliary member after being buffered.
And transmitted to the guide pin, resulting in extremely small force,
There is no adverse effect on guide pins and grooves.

[0013]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of the present invention, and FIG. 2 is a plan view of an auxiliary ring portion, which is a part thereof. In FIG. 1, reference numeral 1 denotes a fixing ring, which has a long groove 1a in the optical axis direction as shown by a broken line in FIG. 2 for guiding a guide pin on a front group and rear group lens moving frame described later. Reference numeral 2 denotes a front group lens moving frame fitted on the inner periphery of the fixed ring 1, 14 denotes an auxiliary ring as a first auxiliary member fitted on the outer periphery of the front group lens moving frame 2, and 15 denotes an inner peripheral portion. Screwed into the front group lens moving frame 2 and fixed.
A support ring 16 serving as a positioning member for positioning and supporting the auxiliary ring 14, and having an outer peripheral portion fitted to the inner periphery of the fixed ring 1 and serving as an auxiliary function for precise operation of the front group lens moving frame 2; 2 is provided between the front group lens moving frame 2 and the auxiliary ring 14 and provided on the periphery of the front group lens moving frame 2 as shown in FIG. Elastic members as a plurality of second auxiliary members for absorbing force, 9 is an auxiliary ring 14
It is a guide pin screwed up.

Reference numeral 3 denotes a front group lens frame rotatably screwed into a screw portion provided on the inner peripheral portion of the front group lens moving frame 2.
Denotes a front group lens, 5 denotes a rear group lens moving frame fitted on the inner periphery of the fixed ring 1, 10 denotes a guide pin screwed to the rear group lens moving frame 5, and 6 denotes the rear group lens moving frame 5. A rear group lens frame 7 is screwed and fixed to an inner peripheral thread portion of the rear group lens, and 7 is a rear group lens. Reference numeral 8 denotes a cam frame rotatably fitted on the outer circumference of the fixed ring 1. The cam frame 8 a for the front group lens moving frame 2 and the cam groove 8 a for the rear group lens moving frame 5 as shown by a broken line in FIG. Two cam grooves of a cam groove (not shown) are provided in the circumferential direction. 11 is a zoom ring, and a set screw 12
Screwed to the cam frame 8.

Numeral 13 denotes a cam frame support ring, which is fitted and fixed to a threaded portion at the tip of the fixed ring 1.
Positioning and support. Here, one or both of the front lens group moving frame 2 and the rear lens group moving frame 5 are collectively referred to as a moving frame. FIG. 3 shows a second embodiment in which one elastic member is provided in place of the plurality of elastic members provided between the front lens group moving frame 2 and the auxiliary ring 14 in the above configuration.

FIG. 4 shows a third embodiment in which a plurality of elastic portions are provided on the auxiliary ring itself instead of the elastic members of the first and second embodiments. With the above-described configuration, in a normal lens moving operation, when the zoom ring 11 is rotated, the cam frame 8 integrated with the set screw 12 rotates, and the cam groove 8a on the cam frame 8 in the circumferential direction is rotated. The guide pins 9, 1 on the auxiliary ring 14 and the rear lens group moving frame 5 are inserted into the long grooves in the optical axis direction on the fixed ring 1.
0 is guided, and finally the front group lens 4 and the rear group lens 7 move on the optical axis, and an arbitrary focal length is set.

In the above operation, the elastic member 16
Alternatively, the elastic portion on the auxiliary ring 14 is not deformed and is considered so as not to affect the movement of the front group lens 4. However, when a predetermined force or more is applied to the guide pin or the cam groove on the front group lens side due to a drop of the camera or the lens, the front group lens frame 3 and the front group lens moving frame 2 are integrated. The applied force is first transmitted to the elastic member 16 or the elastic portion of the auxiliary ring 14, and then transmitted to the guide pin 9 via the auxiliary ring 14 after being buffered. No adverse effects.

Although the present invention has been described with reference to the embodiment in which the lens barrel is manually moved, it is needless to say that the present invention can also be applied to a system which is automatically operated by a drive source such as a motor. Also, the zoom lens barrel has been described as an example, but the present invention is not limited to a lens barrel that moves an optical system by sliding a guide pin and a cam groove with each other.

[0019]

According to the first aspect of the present invention, a very simple structure in which the first auxiliary member, the second auxiliary member, and the positioning member are provided on the moving frame of the conventional lens barrel.
In particular, a first auxiliary member to which a guide pin is fixed
To the rear positioning member on the same moving frame
Configured to be pressed by a second auxiliary body having
The guide pin and the fixed width
Engages with the long groove formed in the groove and the fixing ring, respectively.
Actual lens movement during use
Is the rotation of the zoom ring or distance ring
The cam groove of the cam frame and the long groove of the fixing ring
Said guide pin engaged with
The fixed first auxiliary member moves together in the optical axis direction.
This movement amount is transmitted to the moving frame via the elastic body.
It will be done by being done. At this time, the cam frame
The spring force of the elastic body does not change depending on the rotational position of
The acting force between the id pin and the cam surface of the cam frame does not change
The rotational force on the cam frame is constant,
There is no sound. On the other hand, when a shocking external force exceeding a predetermined level is applied to the moving frame from the front side of the lens , the external force is absorbed or softened by the second auxiliary member made of the elastic body, so that the camera or the lens is accidentally dropped. Provided is a lens barrel capable of minimizing the fall of a guide pin and the deformation of a cam groove caused by unintended handling such as collision with another object or the like, and ensuring a smooth operation between the guide pin and the cam groove thereafter. be able to. Further, in the invention described in claim 2, since the allowed combined elastic function to the auxiliary member, wherein
In addition to obtaining the same effects as the invention described in Item 1,
The configuration can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a first embodiment of the present invention.

FIG. 2 is a plan view showing a main part of the first embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a third embodiment of the present invention.

FIG. 5 is a schematic sectional view of a conventional lens barrel.

FIG. 6 is an enlarged sectional view showing a guide pin portion of a conventional lens barrel.

FIG. 7 is a plan view of the part of FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 fixing ring 2 front group lens moving frame 3 front group lens frame 4 front group lens 5 rear group lens moving frame 6 rear group lens frame 7 rear group lens 8 cam frame 9, 10 guide pin 14 auxiliary ring 15 support ring 16 elastic member

Claims (2)

(57) [Claims] 1. A lens barrel for moving an optical system by sliding a guide pin and a cam groove relative to each other, comprising: a moving frame for moving a photographing lens in an optical axis direction by a moving operation; and a moving frame fixed to the moving frame. A positioning member, and an optical axis on an outer periphery in front of the positioning member on the moving frame.
A first auxiliary member movably provided in a direction, and a first auxiliary member provided between the moving frame and the first auxiliary member, pressing the first auxiliary member against the positioning member at the rear.
And one or more elastic bodies biasing the
Of the cam frame and fixed ring formed on the cam frame.
The first auxiliary member is engaged with each of the formed long grooves.
And a guide pin fixed on a member. When a shocking external force equal to or more than a predetermined value is applied to the moving frame from the front , the external force is absorbed by a second auxiliary member made of the elastic body, and the guide pin and A lens barrel characterized in that direct impact on the cam groove can be reduced. 2. A lens barrel for moving an optical system by sliding a guide pin and a cam groove with respect to each other, comprising: a moving frame for moving an imaging lens in an optical axis direction by a moving operation; and a moving frame fixed to the moving frame. A positioning member, and an optical axis on an outer periphery in front of the positioning member on the moving frame.
The front end abuts on the moving frame
To push itself against the positioning member behind
Auxiliary member that has a biasing elastic part on the front side, and a fixed width cam groove and fixed ring formed in the cam frame
On the auxiliary member in the state of being engaged with the elongated grooves respectively
And a fixed guide pin, wherein when a shocking external force greater than a predetermined value is applied to the moving frame from the front , the external force is absorbed by the elastic portion of the auxiliary member and directly applied to the guide pin and the cam groove. A lens barrel characterized in that it is configured to be able to mitigate mechanical shock.