JPH0199009A - Lens barrel for zoom lens - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a zoom lens barrel, and more particularly to a lens barrel that is capable of automatic focusing in addition to manual focusing.

[Prior art and its problems] In a zoom lens barrel that is capable of automatic focusing in addition to manual focusing,
Switching from manual focusing to automatic focusing is performed as follows in a conventional example in which an operating ring for manual focusing and an operating ring for zooming are configured independently. That is, when focusing manually, the switch on the camera body is set to the manual focus side, the manual operation ring exposed outside the lens barrel is rotated, and when switching to autofocus, the switch is set to the autofocus side. , and connect the coupling shaft of the lens barrel to the drive source inside the camera body. However,
During automatic focusing, the externally exposed manual operation ring also rotates, so if you accidentally touch this manual operation ring during automatic focusing, this may cause a malfunction. In order to prevent such a situation, the length of the manual operation ring in the optical axis direction may be made as short as possible, or the outer diameter of the operating portion of the manual operation ring may be made smaller than that of the fixed lens barrel located outside the manual operation ring. Some efforts were made.

However, doing so as described above makes manual focusing operations difficult.

For long focal length lenses and high-magnification zoom lenses, it is desirable for the manual operation ring to be located near the center of gravity of the lens barrel for operational reasons. The operation ring becomes easier to touch.

In addition, even in a lens barrel configured to perform zooming by moving one operating ring in the optical axis direction and manual focusing by rotating around the optical axis, the manual focusing operating ring ( The zooming operation ring) rotates, making it easy for hands to touch it, which is extremely inconvenient for photographing operations.

The present invention solves the above-mentioned problems in the prior art, that is, it is possible to switch between manual focusing and automatic focusing, and in particular, it is possible to perform manual focusing and zooming using the same operation ring. The purpose of this invention is to provide a zoom lens barrel that is improved so that the operation ring for manual focusing and zooming operations does not rotate during automatic focusing. .

[Means and effects for solving the problems] In order to solve the above problems, the zoom lens barrel according to the present invention has the following features:
A movable barrel that is moved in the optical axis direction during zooming, a first rotary barrel that holds a predetermined lens group that is moved during focusing and zooming and is screwed to the movable barrel, and a first rotary barrel that is rotatably held by the movable barrel. , a second rotating barrel operatively connected to the first rotating barrel with respect to rotation, and an optical axis that moves integrally with the movable barrel in the direction of the optical axis operated during zooming and operated during manual focusing. Surrounding the movable barrel is an operating barrel that can rotate relative to the movable barrel, and is arranged between the second rotating barrel and the operating barrel, and rotates the second rotating barrel integrally with the operating barrel during manual operation. It is comprised of a switching means that can take a connected position or a disconnected position that allows the second rotary barrel to rotate independently from the operation barrel during automatic focusing.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a zoom lens barrel showing an embodiment of the present invention. In the figure, the zoom lens barrel includes a fixed lens barrel 14, a first group moving frame 10 fitted to its inner peripheral surface, and a focus intermediate barrel 3 screwed to its outer peripheral surface.
0, switching ring 4 fitted to the outer peripheral surface of the fixed lens barrel 14
4. It includes an operating ring 40 disposed outside the first group moving frame and the switching ring, and a leaf spring 58 interposed between the focus intermediate cylinder 30 and the operating ring 40.

The first lens group holding frame 12 screwed onto the first group moving frame 10 holds the first lens group □ on its inner periphery, and has a protrusion 12a protruding in the radial direction on its outer peripheral surface. . A female helicoid 12b is engraved on the inner peripheral surface of the large diameter portion of the first lens group holding frame 12, and a male helicoid 10. It is screwed together with a. The first lens group moving frame 10 is slidable in the optical axis direction, and slidably holds the second lens group moving frame 16 on its inner peripheral surface. The second group moving frame 16 holds the second group lens L2.

A flange 10b is provided behind the male helicoid 10a of the first group moving frame 10, and a flange 18a of the external lens barrel 18 is fixed thereto with machine screws 20. A female thread 18b is provided on the inner peripheral surface of the external lens barrel 18, and is screwed into a male thread 22a on the outer peripheral surface of a distance scale ring 22 disposed inside the outer lens barrel 18.
is rotatable. A cutout window 18c and a stepped portion 18d are provided on the outer peripheral surface of the external lens barrel 18, and a transparent resin plate 24 is fixed to the stepped portion 18d so that the distance scale on the distance scale ring 22 can be read. .

A straight groove 22b is provided on the inner diameter surface of the distance scale ring 22, and the protrusion 12a of the first group lens holding frame 12 is slidably engaged therein. An interlocking key 26 is fixed to the rear end surface of the distance scale ring 22 with screws 28. The interlocking key 26 passes through the notch 10c of the flange 10b of the first group moving frame 10 and engages with the notch 30a of the focus intermediate cylinder 30. A female thread 30b is provided on the inner circumferential surface of the focus intermediate cylinder 30, and is screwed together with a male screw 10d provided on the outer circumferential surface of the first group moving frame 10, thereby making the focus intermediate cylinder 30 rotatable. A straight key 32 is fixed to the rear end of the focus intermediate cylinder 30 with a screw 34, and the straight key 32 is engaged with a keyway 36a of a segment gear member 36. The segment gear member 36 is
It is rotatably fitted on the outer peripheral surface of the fixed lens barrel 14 and has a toothed portion 36b on the circumferential surface, which is connected to the toothed portion 38 of the pinion gear 38.
It meshes with a.

The operating ring 40 is rotatable by being held between the stepped part of the flange 10b of the first group moving frame 10 and the external lens barrel 18, and the zooming intermediate barrel 42 is configured to provide light to the inner peripheral surface of the switching ring 44. It is fitted so as to be slidable in the axial direction. The switching ring 44 is held by the fixed lens barrel 14 so as to be rotatable by a predetermined angle, and a scale indicating the zoom focal length, etc. is displayed on the outer peripheral surface of the switching ring 44. Since the pin 46 installed in the fixed lens barrel 14 is fitted into the straight groove 42a, the zooming intermediate barrel 42
cannot be rotated. The adjusting intermediate cylinder 42 is connected to the operating ring 4.
0 and a presser plate 48, and moves together with the operating ring 40 in the optical axis direction.

A switching intermediate ring 5 is provided on the outer peripheral surface of the front end of the zooming intermediate cylinder 42.
2 is fitted so as to be rotatable and slidable in the optical axis direction, and a portion thereof is extended rearward to form an extension portion 52a. As shown in FIG. 3, the switching intermediate ring 52 is provided with a lead groove 52b, into which a pin 54 implanted in the zooming intermediate cylinder 42 is fitted. Further, a bottle 56 implanted in the switching ring 44 is fitted into a straight groove 52b provided in the extension portion 52a. Therefore, when the switching ring 44 is rotated, the switching intermediate ring 52 is also rotated by the same amount.
Lead groove 5 formed in the bin 54 and the switching intermediate ring 52
2c causes the switching ring 44 to also move in the optical axis direction. Note that a recess 42c is formed in the zooming intermediate cylinder 42 by the extent of the extension portion 52a, so that rotation of the switching intermediate ring 52 is not hindered.

The switching intermediate ring 52 further has a flange 52d at the front end,
When moving toward the subject in the optical axis direction, the flange 5
2d pushes the leaf spring 58 radially outward. The leaf spring 58 connects one end to the operating ring 40 with a screw 60.
An engagement piece 62 made of synthetic resin is provided at the tip of the other end, and the engagement piece 62 is always urged inward in the radial direction. As shown in FIG. 4, a plurality of grooves 30c that engage with the engagement pieces 62 are provided at predetermined intervals over the entire circumferential direction at the end of the intermediate focus tube 30 on the camera body side.

A bin 66 is erected on the second group moving frame 16, and a bin 70 is erected on the third group moving frame 68. The third lens group moving frame 68 holds a third lens group L3 and a fourth lens group L4.

The bottles 66 and 70 are located in the slots 10 of the first group moving frame 10, respectively.
e and 10f, and are engaged with straight grooves 14e and 14f of the fixed lens barrel 14, and further fitted into cam grooves 74a and 74b of a cam barrel 74 fitted on the outside of the fixed lens barrel 14. Further, a pin 76 is erected on the first group moving frame 10,
It engages with the straight groove 14g of the fixed lens barrel 14 and is fitted into the lead groove 74c of the cam barrel 74.

As described above, the pin 46 fits into the straight groove 42a of the zooming intermediate cylinder 42, and also fits into the circumferential groove 74 of the cam cylinder 74.
It is also included in d. Therefore, the cam cylinder 74 cannot move in the optical axis direction, but can only rotate.

Focusing is performed by moving the first lens group L0, and the first, second, and third lens groups Lx.

Zooming is performed by moving L2 and L3 in the optical axis direction.

Referring to FIG. 2, the pinion gear 38 has a shaft portion 38a extending toward the camera body, and a stepped portion 38b is provided at the end of the shaft portion 38a. A clutch ring 86 is fitted onto the outer peripheral surface of this stepped portion 38b. This clutch ring 86 is movable in the axial direction on the outer circumferential surface of the stepped portion 38b, and both are configured to rotate integrally. A clutch lever 88 is inserted into an annular groove 86a provided in the center of the clutch ring 86.
A disc-shaped tip 88a of the clutch gear 90 is fitted therein, and a groove 86a that engages with a convex projection 90a provided on the clutch gear 90 is provided at the end on the camera body side.

The clutch lever 88 is adapted to rotate about a shaft 92 and is biased counterclockwise by a torsion spring 94. A pin 96 is provided on the opposite side of the tip 88a of the clutch lever 88, and the pin 96 is in contact with the protrusion 44a provided on the switching ring 44, so that the clutch lever 88
rotation is restricted. The clutch gear 90 meshes with a coupling gear 102 via a step gear 98 and a step gear 100 for deceleration. A coupling portion 102a that engages with a coupling shaft (not shown) of the camera body is provided at one end of the coupling gear 102, and is connected to and driven by a drive motor within the camera body.

The operation of this embodiment will be explained below.

First, to explain zooming, use the operation ring 4.
0 in the direction of arrow A (in front of the lens barrel) in FIG. At the same time, the cam cylinder 74 rotates due to the engagement of the pin 76 with the linear groove 14g and the lead groove 74c. At this time, the zooming intermediate cylinder 42 also moves integrally. When the cam barrel 74 rotates, the pins 66 and 70 engage with the cam grooves 74a and 74b and the linear grooves 14e and 14b of the fixed lens barrel 14, so that the second group moving frame 16 and the third group moving frame 68 are The second lens group L2, the third lens group L3, and the fourth lens group L4 move in the axial direction to perform zooming.

Next, manual focusing operation (manual focusing) will be explained. When the operating ring 40 is rotated, the leaf spring 58
Since the engaging piece 62 is engaged with the groove 30a (connected position), the focus intermediate cylinder 30 rotates integrally with the operation ring 40, and the interlocking key 26 is engaged with the notch 30a, so the distance The scale ring 22 rotates integrally with the operation ring 40. When the distance scale ring 22 rotates, since the protrusion 12a is fitted into the linear groove 22a, the lune holding frame 12 also rotates, and the lune group is held through the screw engagement between the male helicoid 10a and the female helicoid 12b. The frame 12 rotates and moves in the optical axis direction, and the lens group L0 moves to perform focusing.

When the focus intermediate cylinder 30 rotates, the segment gear member 36 rotates via the linear key 32, and the pinion gear 38 screwed therewith rotates, thereby rotating the clutch ring 86. However, since the groove 86c of the clutch ring 86 and the groove 90a of the clutch gear 90 are disconnected, the clutch gear 90, the stage gears 98 and 100, and the coupling shaft 102 do not rotate.

That is, the focusing mechanism within the lens barrel is separated from the drive motor within the camera body.

Switching from manual focusing to automatic focusing is performed as follows.

When the switching ring 44 is rotated in the direction of arrow B in FIG. 2, the protrusion 44a also moves in the same direction, and the biasing force of the return spring 94 causes the clutch lever 88 to rotate counterclockwise. As a result, the clutch ring 86 moves rightward in FIG. 2, and its groove 86b engages with the protrusion 90a of the clutch gear 90. At the same time, since the pin 56 on the switching ring 44 is fitted into the linear groove 52b, the intermediate switching ring 52 also rotates. At this time, the switching intermediate ring 52
The pin 54 on the zooming intermediate cylinder 42 is inserted into the lead groove 52c.
is inserted, and since the zooming intermediate cylinder 42 cannot rotate, the switching intermediate ring 52 moves toward the subject while rotating.

Accordingly, the flange 52d of the switching intermediate ring 52 pushes the leaf spring 58 radially outward, thereby disengaging the engagement piece 62 from the groove 30c of the focus intermediate cylinder 30 (separation position). Therefore, the operating ring 40 and the focus intermediate cylinder 30 are free from each other, and even if the operating ring 40 is rotated, the focus intermediate cylinder 30 does not rotate.

During automatic focusing, the coupling portion 102a engages with a coupling portion (not shown) on the camera body side, and the coupling shaft 102, stepped gears 98 and 100, and clutch gear 90 rotate.

At this time, the groove 90a of the clutch gear 90 and the protrusion 86b
are engaged, so the clutch ring 90, that is, the pinion gear 38, rotates. When the pinion gear 38 rotates, the segment gear member 36 rotates with it, and as a result, the second lens group moves and a focusing operation is performed in the same manner as during automatic focusing.

During this automatic focusing operation, since the keyway 36a provided on the outer circumference of the segment gear member 36 and the linear key 32 are engaged, the focus intermediate cylinder 30 also rotates at the same time. However, since the engagement piece 62 of the leaf spring 58 is not fitted into the groove 30c, the operating ring 40 does not rotate. Therefore, even if the photographer accidentally touches the operation ring 40 during automatic focusing,
It does not interfere with focusing operation.

Also, since the operation ring 40 does not rotate during automatic focusing,
The length of the operating ring 40 in the optical axis direction can be increased, making zooming operations and manual focusing operations easier.

Furthermore, a distance scale window 18d is provided on the external lens barrel 18 that moves integrally with the operation ring 40 in the optical axis direction, and the scale of the distance scale ring 22 can be seen through the window 18d, so that the distance scale during automatic focusing can be seen. observation becomes easier.

Note that the present invention is not limited to the above embodiments,
It goes without saying that changes and improvements can be made as appropriate within the scope of not impairing the spirit of the invention. For example, the lens barrel only needs to have at least a lens group (lens group L1 in the embodiment) that is moved during zooming and focusing, and it is arbitrary what kind of lens groups it has. Furthermore, it goes without saying that the switching mechanism between automatic focusing and manual focusing can be changed and improved as necessary.

[Effects of the invention] As described above, according to the invention, the switching mechanism is switched so that the operation ring that is moved for zooming operations and manual focusing operations does not rotate during manual focusing. Even if you accidentally touch the operation ring during manual focusing, the focusing operation will not be affected.6Moreover, the above switching mechanism has a simple structure and does not take up much space, so
Because of this arrangement, the lens barrel does not become larger.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a zoom lens barrel according to the present invention, FIG. 2 is an explanatory diagram of a gear connection part, and FIG.
The figure is a view taken along arrow C in FIG. 1, and FIG. 4 is a sectional view taken along line DD in FIG. [Explanation of symbols of main parts] 12-...1st group moving frame 22...Distance scale ring 30...Focus intermediate cylinder 40...Operation ring 44-Switching ring 58...Plate spring L□--・Lens group

Claims (1)

[Claims] A movable barrel that is movable in the optical axis direction but not rotatable around the optical axis; a first rotary barrel that holds a predetermined lens group and is screwed to the movable barrel; a second rotary tube rotatably held by the movable tube and operatively connected to the first rotary tube with respect to rotation; a second rotary tube that moves integrally with the movable tube in the optical axis direction and rotates around the optical axis; an operating barrel that is rotatable relative to the movable barrel; an operating barrel that is disposed between the second rotating barrel and the operating barrel, and that rotates the second rotating barrel integrally with the operating barrel; and a switching means that can take a connected position that allows the camera to rotate independently or a disconnected position that allows it to rotate independently; during manual focusing, the switching means is set to the connected position and the operating barrel is rotated, and the second rotating barrel is rotated. The lens group is moved by rotating the first rotary barrel through the rotation of , and during autofocusing, the switching means is set to a detached position and the second rotary barrel is rotated by an electric drive source. By this, the lens group is moved through the rotation of the first rotary barrel, and during zooming, the movable barrel is moved by moving the operation barrel in the optical axis direction, and the movable barrel is integrated with the first rotary barrel. A zoom lens barrel characterized in that at least the lens group is moved in the optical axis direction.