JPH0876189A - Extending/contracting mechanism for bellows lens hood - Google Patents

Abstract

PURPOSE: To provide an extending/contracting mechanism for a bellows lens hood capable of making both of rough and fine adjustments easy. CONSTITUTION: Front and rear frames 14 and 16 are connected by bellows 12 and an operating part 60 is turnably attached to a frame material 40. A cam member 50 is attached to the operating part 60 to be integrally turned and engaged a cam follower 38. Arm members 32a-32d are connected to the front and rear frames 14 and 16, to be freely moved in a direction perpendicular to the extending/contracting directions and supported freely turnably each other. When the operating part 60 is turned, the cam member 50 is integrally turned, the arm members 32a 32d are extended/contracted in the extending/contacting directions of the bellows 12 with the cam follower 38, to guide the front and rear frames 14 and 16 in the extending/contracting directions of the bellows 12. A mark 61 provided on the surface of a control panel 62 is aligned with a reference line 44 provided on the frame material 40, so that the extending quantity of the bellows 12 can be properly adjusted in accordance with each lens mounted on a camera main body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for expanding and contracting a bellows lens hood used in a camera or the like.

[0002]

2. Description of the Related Art Conventionally, as a mechanism for expanding and contracting a bellows lens hood, for example, a pantograph which connects a front frame to which a vignette plate or the like can be attached and a rear frame which is connected to a camera body to which a lens, a filter and the like are fixed is connected. Are known. As this expansion / contraction mechanism, there are a manual adjustment mechanism and a screw adjustment mechanism.

[0003]

However, with the conventional manual method, the adjustment becomes rough and it is difficult to make fine adjustment. On the other hand, in the case of adjusting with a screw, the screw has to be adjusted every time the expansion and contraction is adjusted, and the work is complicated.

An object of the present invention is to provide an expansion / contraction mechanism for a bellows lens hood which can be easily adjusted by either coarse adjustment or fine adjustment.

[0005]

An expansion / contraction mechanism for a bellows lens hood according to the present invention is an expansion / contraction mechanism for a bellows lens hood in which a front frame and a rear frame are connected by a bellows so as to expand and contract. It is characterized in that it comprises a pantograph that is connected to extend and contract, an operating portion that is rotatably attached to the pantograph, and a cam member that is integrally attached to the operating portion and that engages with a cam follower provided on the pantograph. There is.

A mark indicating the amount of expansion and contraction of the bellows corresponding to the lens attached to the camera body may be provided on the operation portion, and a reference line may be provided at a position corresponding to the mark on the pantograph.

Further, the cam member may have a curved cam groove, and the cam follower may be slidably engaged with the cam groove.

Further, the pantograph has a frame member on which a cam follower guide groove extending parallel to the front frame and the rear frame is formed and an operating portion is attached, and the cam follower slidably engages with the cam follower guide groove. May be.

Further, the pantograph is fixed to the front frame and the rear frame, respectively, and a front frame engaging member and a rear frame engaging member in which roller guide grooves extending along the front frame and the rear frame are formed, and a roller guide groove. A guide roller slidably engaged with.

[0010]

The present invention will be described below with reference to illustrated embodiments. 1 shows an embodiment of the present invention, FIG. 1 is a right side view when the bellows lens hood is stored, FIG. 2 is a right side view when the bellows lens hood is extended, and FIG. 3 is FIG.
FIG. 4 is a cross-sectional view taken along line III-III in FIG. 4, and FIG. 4 is an exploded perspective view of the expansion / contraction mechanism of the bellows lens hood.

As can be understood from FIGS. 1 and 2, the front frame 14 and the rear frame 16 are connected by a bellows 12 and are expandable and contractible, and the inside thereof is shielded from the outside. Front frame 1
A vignette plate can be attached to 4, for example, and the rear frame 16 is connected to a camera body (not shown) on which predetermined lenses, filters and the like are mounted. When the operation portion 60 is rotated, the cam member 50 is rotated, whereby the front frame 14 is advanced and retracted via the pantograph 30, and the bellows 12 is expanded and contracted.

The front frame 14 and the rear frame 16 include front frame engaging members 1
8 and the rear frame engaging member 20 are fixed. The pantograph 30 includes arm members 32a to 32d, fulcrum rollers 34a to 34e, a cam follower 38, and a guide roller 3.
6, 37 and the frame member 40, and the arm member 32a,
32b is connected to the front frame engagement member 18 via a guide roller 36 and a fulcrum roller 34c, and the arm members 32c, 32
d is connected to the rear frame engaging member 20 via the guide roller 37 and the fulcrum roller 34e.

The arm members 32a to 32d are elongated plate-like members, are formed in substantially the same shape, and are rotatably connected to each other by a cam follower 38 and fulcrum rollers 34a, 34b, 34d. That is, the arm members 32a and 32b have the fulcrum roller 3 at the center thereof.
4a, and the arm members 32c and 32d are connected by a fulcrum roller 34b at their central portions. Further, the end of the arm member 32a and the end of the arm member 32c are connected by a fulcrum roller 34d, and the arm member 3
The end of 2d and the end of the arm member 32b are cam followers 3
8 are linked together.

The front frame engaging member 18 is formed with a roller guide groove 22 extending in parallel with the front frame 14 and the rear frame 16.
A guide roller 36 provided at the tip of the arm member 32a is slidably engaged with the roller guide groove 22. Similarly, the rear frame engaging member 20 is formed with a roller guide groove 23 extending parallel to the front frame 14 and the rear frame 16, and the roller guide groove 23 is provided with a guide roller 37 provided at the tip of the arm member 32c. Are slidably engaged.

The frame member 40 is provided between the front frame engaging member 18 and the rear frame engaging member 20 and is parallel to them. The frame member 40 is formed by bending one elongated plate-shaped member into a U-shape, that is, from two plate-shaped portions facing both side surfaces of the bellows 12 and a plate-shaped portion facing the lower surface of the bellows 12. It is configured and is also connected to a pantograph (not shown) provided on the lower side surface and the left side surface of the bellows 12. A cam follower guide groove 46 extending in parallel with the front frame 14 and the rear frame 16 is formed in the frame member 40. The cam follower guide groove 46 is located between the roller guide grooves 22 and 23 formed in the front frame engaging member 18 and the rear frame engaging member 20, and has substantially the same length as these. Cam followers 38 provided on the arm members 32d and 32b are engaged with the cam follower guide grooves 46.

As shown in FIG. 3, the operating portion 60 includes a disc-shaped operating panel 62 and a shaft portion 64 fixed to the lower surface of the operating panel 62.
have. A shaft stop portion 66 is formed at the tip of the shaft portion 64, and a groove portion 65 recessed along the circumferential direction is formed near the shaft stop portion 66. The groove 65 is the frame member 40.
It is rotatably fitted in the hole 42 formed in the frame 42, whereby the operating portion 60 is rotatable with respect to the frame member 40.

The cam member 50 has a thin plate shape and, as shown in FIG. 4, an operating portion 60 is provided in a shaft hole 54 formed at a corner portion thereof.
The shaft portion 64 of is inserted. An annular stopper member 70 is fitted on the shaft portion 64, and the upper end of the stopper member 70 is
The cam member 50 is fixed by being sandwiched by the operation portion 60 by the lower surface of the step portion 67 formed on the shaft portion 64. Therefore, the cam member 50 can rotate integrally with the operation unit 60.

An arcuate curved surface portion 52 is formed on the outer peripheral edge of the cam member 50 on the side opposite to the shaft hole 54.
A cam groove 56 that curves along 2 is formed. The distance between each portion of the cam groove 56 and the shaft portion 64 of the operation portion 60 continuously changes, and the first end portion 56a of the cam groove 56 is relatively far from the shaft portion 64 of the operation portion 60, and The second end portion 56b of the cam groove 56 is relatively close to the shaft portion 64 of the operation portion 60. The cam follower 38 is movably engaged with the cam groove 56. That is, the cam follower 38 is engaged with both the cam groove 56 and the cam follower guide groove 46, and the cam follower 38 rotates in response to the rotation of the cam member 50.
6 and the cam follower guide groove 46.

When the cam member 50 is in the position shown in FIG. 1, that is, when the first end portion 56a of the cam groove 56 is close to the frame member 40, the cam follower 38 is the farthest from the operating portion 60 by the cam groove 56. Positioned and the pantograph 30 is in the folded state. On the other hand, when the cam member 50 is at the position shown in FIG. 2, that is, when the second end portion 56b of the cam groove 56 is close to the frame member 40,
The cam follower 38 is set at the position closest to the operating portion 60 by the cam groove 56, and the pantograph 30 is in a spread state. Thus, the position of the cam follower 38 with respect to the rotation of the cam member 50 is determined by the curved shape of the cam groove 56. The curved shape of the cam groove 56 is appropriately determined according to the purpose.

Two marks 61a and 61b are provided on the upper surface of the operation panel 62, that is, on the surface side which is visible to the operator. These marks 61a and 61b correspond to the expansion / contraction amount (extending amount) of the bellows 12 for each lens that can be attached to the camera body. In addition, the frame member 40 has a reference line 44
Are provided at positions visible on the outside of the operation panel 62 and at positions corresponding to the marks 61a and 61b. Operation panel 6 so that mark 61 is aligned with reference line 44
When you rotate 2, the bellows 12
Is expanded and contracted.

Next, the operation of this embodiment will be described. When the operation panel 62 is rotated counterclockwise from the state shown in FIG. 1, the cam member 50 rotates integrally with the operation panel 62, and the cam follower 38 moves along the cam groove 56 formed in the cam member 50. The cam follower guide groove 4 is slidably guided from the position of the first end 56a toward the position of the second end 56b.
The inside of 6 slides in the direction approaching the operation panel 62 (rightward in FIG. 1). Therefore, one end of each of the arm members 32b and 32d to which the cam follower 38 is fixed is attached to the cam follower 38.
Guided in the direction of the operation panel 62 together with the cam follower 3
The intersection angle of the arm members 32b and 32d around 8 increases and the other ends of the arm members 32b and 32d rotate in a direction away from each other.

Further, the arm members 32a and 32c are connected to the arm members 32b and 32d via fulcrum rollers 34a and 34b.
Since they are connected to each other, like the arm members 32b and 32d, they rotate about the fulcrum roller 34d in the direction in which the other end is separated. Therefore, the guide rollers 36 and 37 move to the right in FIG. 1 along the roller guide grooves 22 and 23, respectively, whereby the front frame engaging member 18 and the rear frame engaging member 20 are pushed out in the directions in which they are separated from each other. , Move parallel to each other. Further, since pantographs are similarly provided on the lower side surface and the left side surface of the bellows 12 (not shown), the front frame 14, the rear frame 16 and the frame member 40 are also pushed out in the direction of separating from each other on the lower side surface and the left side surface. As shown in FIG. 2, the front frame 14, the rear frame 16 and the frame member 40 move in parallel with each other,
The bellows 12 stretches.

On the other hand, when the operation panel 62 is rotated clockwise from the state shown in FIG. 2, the cam member 50 rotates in the clockwise direction integrally with the operation panel 62, and in the opposite direction to the above, the cam groove 56 is formed in the cam groove 56. The cam follower 38 slides from the position of the second end 56b toward the position of the first end 56a. That is, the cam follower 38 slides in the cam follower guide groove 46 in the direction away from the operation panel 62 (leftward in FIG. 2). Since one ends of the arm members 32b and 32d are moved in the direction away from the operation panel 62 together with the cam follower 38, the crossing angle of the arm members 32b and 32d becomes small, and the other ends of the arm members 32b and 32d approach each other. Turn to. The arm members 32a and 32c also rotate in the direction in which the crossing angle becomes smaller. Therefore, the front frame engaging member 18 and the rear frame engaging member 20 move toward each other, and the bellows 12 contracts.

As described above, according to this embodiment, the arm members 32a to 32d are connected by the fulcrum rollers 34a to 34e, the guide rollers 36 and 37, and the cam follower 38 so as to rotate smoothly, and the guide roller 3 is used.
6, 37 and the cam follower 38 are provided in the roller guide groove 2
2, 23 and the cam follower guide groove 46 are engaged so as to move smoothly, and no means for forcibly urging the rotation of the operation panel 62 in a certain direction is provided. It is easy and the bellows 12 can be manually moved in the expansion / contraction direction, and the expansion / contraction amount of the bellows 12 can be easily and roughly adjusted.

Further, in this embodiment, the bellows 12 is expanded and contracted by rotating the operation panel 62 largely. Therefore, the amount of expansion and contraction of the bellows 12 can be finely adjusted, and the amount of expansion and contraction can be adjusted with much higher accuracy than, for example, the operator directly expanding and contracting the bellows 12.

Further, in the present embodiment, the marks 61a, 61
b is provided at a position where the bellows 12 expands and contracts by an amount corresponding to the lens mounted on the camera body. Therefore, the bellows 12 can be operated by simply rotating the operation panel 62 to a position where the marks 61a and 61b are aligned with the reference line 44.
The amount of expansion and contraction of is properly and easily adjusted.

[0027]

As described above, according to the present invention, coarse adjustment,
The expansion / contraction mechanism of the bellows lens hood can be easily adjusted by either fine adjustment.

According to the second aspect of the invention, the amount of expansion and contraction of the bellows can be adjusted appropriately and easily according to each lens attached to the camera body.

[Brief description of drawings]

FIG. 1 is a right side view of a bellows lens hood according to an embodiment of the present invention when it is stored.

FIG. 2 is a right side view when the bellows lens hood is being extended.

3 is a cross-sectional view taken along the line III-III in FIG.

FIG. 4 is an exploded perspective view of a telescopic mechanism of the bellows lens hood according to the present embodiment.

[Explanation of symbols]

 12 bellows 14 front frame 16 rear frame 18 front frame engaging member 20 rear frame engaging member 22, 23 roller guide groove 30 pantograph 32a to 32d arm member 34a to 34e fulcrum roller 36, 37 guide roller 38 cam follower 40 frame material 44 reference Line 46 Cam follower guide groove 50 Cam member 56 Cam groove 60 Operation part 61 Mark

Claims (5)

[Claims] 1. An expansion / contraction mechanism for a bellows lens hood in which a front frame and a rear frame are elastically connected by a bellows, wherein the pantograph connects the front frame and the rear frame in an expandable and contractable manner. An expansion / contraction mechanism for a bellows lens hood, comprising: an attached operation section; and a cam member that is integrally attached to the operation section and that engages with a cam follower provided on a pantograph. 2. The operation section is provided with a mark indicating the amount of expansion and contraction of the bellows corresponding to the lens attached to the camera body, and at a position corresponding to the mark of the pantograph,
The expansion / contraction mechanism of the bellows lens hood according to claim 1, wherein a reference line is provided. 3. The bellows lens hood according to claim 1, wherein the cam member has a curved cam groove, and the cam follower slidably engages with the cam groove. Telescopic mechanism. 4. The pantograph has a frame member to which a cam follower guide groove extending parallel to a front frame and a rear frame is formed, and the operation portion is attached, wherein the cam follower is
The expansion / contraction mechanism of the bellows lens hood according to claim 1, wherein the expansion / contraction mechanism is slidably engaged with the cam follower guide groove. 5. A front frame engaging member and a rear frame engaging member, wherein the pantograph is fixed to the front frame and the rear frame, respectively, and roller guide grooves extending along the front frame and the rear frame are formed. And a guide roller slidably engaged with the roller guide groove.
The expansion / contraction mechanism of the bellows lens hood described in 2.