JP3462596B2 - Telescopic mechanism of bellows lens hood - Google Patents

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, a pantograph for connecting a front frame to which a vignette plate or the like can be attached and a rear frame connected to a camera body to which a lens, a filter and the like are fixed is connected. Those who have 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]

In order to achieve the above-mentioned object, 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 elastically connected by a bellows. A rotatable operation part, a pantograph connecting the front frame and the rear frame in a stretchable manner, a cam follower provided on the pantograph, and a guide means for guiding the cam follower in a direction substantially orthogonal to the expansion and contraction direction of the bellows. A connecting member that connects the cam follower and a position eccentric from the center of the operating portion is provided, and the front frame and the rear frame are moved in the bellows expansion and contraction direction by rotating the operating portion.

Further, if the operation portion is provided with a mark indicating the amount of expansion and contraction of the bellows corresponding to the lens attachable to the camera body, and a reference line is provided at a position corresponding to the mark on the pantograph, it is possible to perform adjustment. It is preferable that the reference line and the mark can be referred to, and the amount of expansion and contraction of the bellows can be adjusted more appropriately and easily according to each lens that can be attached to the camera body.

[0007]

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 sectional view taken along line III-III in FIG. 4, and FIG. 4 is an exploded perspective view of a telescopic mechanism of the bellows lens hood.

As can be seen 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 unit 60 is rotated, the front frame 14 moves back and forth via the pantograph 30,
The bellows 12 expands and contracts.

The pantograph 30 includes a front frame 14 and a rear frame 16.
And has a function of guiding them in a direction of expansion and contraction, and has arm members 32a to 32 to be described later.
d, fulcrum rollers 34a, 34b, cam followers 38a,
38b, guide rollers 36a, 36b, 37a, 37
b, front frame engaging member 18, rear frame engaging member 20, and frame member 4
It is composed of 0 and the like.

The front frame engaging member 18 and the rear frame engaging member 20 are
Roller guide grooves 22a, 22b and 23a, 23b which are fixed to the front frame 14 and the rear frame 16 and extend in parallel along the front frame 14 and the rear frame 16 are formed at both ends thereof.

The arm members 32a to 32d are formed of elongated plate-like members and are smoothly rotatably connected to each other. That is, the arm members 32a and 32b are connected by the fulcrum roller 34a at the center thereof, and the arm members 32c and 32d are similarly connected by the fulcrum roller 34b.

The arm members 32a to 32d are connected to the front frame engaging member 18 and the rear frame engaging member 20 via guide rollers 36a, 36b, 37a, 37b. The guide rollers 36a and 36b are provided at the end portions of the arm members 32a and 32b, and the roller guide grooves 22a and 22 are respectively provided.
It is slidably engaged with b. Similarly, arm member 3
Guide rollers 37a provided at the ends of 2c and 32d,
37b is engaged with the roller guide grooves 23a and 23b. As a result, the guide rollers 36, 37 can move smoothly along the roller guide grooves 22, 23.

The cam followers 38a and 38b are provided on the pantograph 30 and rotatably connect the arm members 32b and 32d and the arm members 32a and 32c to each other.

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.

The frame member 40 is provided with cam follower guide grooves 46a and 46b extending parallel to the front frame 14 and the rear frame 16. Cam follower guide grooves 46a, 46b
Is located between the roller guide grooves 22 and 23 facing each other, and has substantially the same length as these. In the cam follower guide grooves 46a and 46b, the cam follower 3 described above is provided.
8a and 38b are movably engaged with each other.

As shown in FIG. 3, the operating portion 60 is located on the side surface of the bellows 12 that can be easily operated by the operator, and is rotatably provided around its axis. The operation unit 60 includes a disc-shaped operation panel 62, a shaft portion 64 fixed to the lower surface of the operation panel 62, and connecting member support shafts 70a and 70b.

The hole 42 formed in the frame member 40 is rotatably fitted in the groove portion 65 formed along the circumferential direction of the shaft portion 64 so that the operating portion 60 can be rotated on the frame member 40. Is attached to. The shaft stopper 66 formed at the tip of the shaft 64 is
The operation unit 60 is prevented from coming off the frame member 40.

The connecting member support shafts 70a and 70b are formed by the shaft portion 7.
1a and 71b and a bearing portion 72 formed at the lower end of these
a and 72b. Shaft 71a, 71b
Are fixed at positions on the lower surface of the operation panel 62 that are eccentric from the center and face each other.
One end of is rotatably supported. Bearing portion 72a, 72
b prevents the connecting members 50a and 50b from coming off the operating portion 60.

The connecting members 50a, 50b are eccentric from the center of the operating portion 60 and the cam followers 38a, 38b.
And has a function of transmitting a displacement due to the rotation of the operation portion 60 to the pantograph 30 (arm members 32a to 32d) as a displacement in a direction substantially orthogonal to the expansion / contraction direction of the bellows 12. Such connecting members 50a, 50b
4, is formed in an elongated plate-like member, and has shaft holes 54a and 54b and connecting holes 56a and 56 at both ends.
b is drilled.

Shaft portions 71a, 71 are provided in the shaft holes 54a, 54b.
b is rotatably fitted and is rotatably connected to the operation panel 62 at that position. Thereby, the connecting member 50a,
50b moves smoothly with the rotation of the operation unit 60.

A cam follower 3 is provided in each of the connecting holes 56a and 56b.
8a and 38b are rotatably fitted, and the connecting members 50a and 50b are connected to the frame member 40 and the arm members 32a to 32d via the cam followers 38a and 38b. The connecting members 50a and 50b are the cam followers 3
8a, 38b together with cam follower guide grooves 46a, 4
It is movable along 6b.

When the cam follower 38 is stored as shown in FIG.
The a and 38b are set at the outermost positions in the direction orthogonal to the expansion / contraction direction of the bellows 12, that is, at the positions farthest from the operation unit 60, and the pantograph 30 is set in the folded state.

On the other hand, at the time of feeding shown in FIG. 2, the cam followers 38a, 38b are set at the innermost position in the direction orthogonal to the expansion / contraction direction of the bellows 12, that is, the position closest to the operating portion 60. Pantograph 30
Is set in an unfolded state.

The position of the cam follower 38 with respect to the rotational position of the operation panel 62 is determined by the connecting member support shafts 70a and 70b.
Is determined according to the eccentric position of the above and the lengths of the connecting members 50a and 50b, and these values are appropriately determined according to the purpose.

Four marks 61a to 61d are provided in four directions on the upper surface of the operation panel 62, that is, on the surface side which is visible to the operator. In addition, the frame member 40 has reference lines 44a, 4
4b is a position visible outside the operation panel 62,
It is provided at a position corresponding to the marks 61a to 61d. When the operation panel 62 is rotated while referring to the mark 61 and the reference line 44 when adjusting the amount of expansion and contraction of the bellows 12, the bellows 12 can be quickly and accurately adjusted to a predetermined amount of expansion and contraction.

Further, in this embodiment, the marks 61a to 61d are provided.
Is provided so as to meet the reference lines 44a and 44b when the bellows 12 is most stowed and most extended.
For example, if a mark is provided according to the amount of extension of the attachable lens, the amount of extension corresponding to each lens can be adjusted very quickly and appropriately, which is effective.

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 connecting member support shafts 70a and 70b rotate integrally with the operation panel 62, and the cam follower 3 via the connecting members 50a and 50b.
8 is slidably guided along the cam follower guide grooves 46a, 46b in a direction substantially orthogonal to the expansion / contraction direction and in a direction close to the operation panel 62. Thereby, the arm members 32b to which the cam followers 38a and 38b are connected,
One ends of 32d and 32a, 32c are also guided in the direction of the operation panel 62, and arm members 32b, 32d and 32a, 32c centering on the fulcrum rollers 34a, 34b, respectively.
The crossing angle α of the arm members 32b, 32d becomes large.
And the other ends of 32a and 32c move in a direction away from each other.

In synchronization with the above operation, each guide roller 36,
37 also moves in the direction of approaching the operation panel 62 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 direction of separating from each other, and are parallel to each other. Move to. Further, the pantographs provided on the lower side surface and the left side surface of the bellows 12 (not shown) also operate in synchronization with the above operation, and the front frame 14, the rear frame 16 and the frame member 40 are pushed out in a direction in which they are separated from each other. As shown, the front frame 14, the rear frame 16, and the frame member 40 move in parallel with each other, and the bellows 12 extends.

On the other hand, when the operation panel 62 is rotated clockwise from the state shown in FIG. 2, each connecting member supporting shaft 70 is moved to the operation panel 62.
And the arm members 32 connected to the cam followers 38 and the cam followers 38, which rotate in a clockwise direction integrally with the cam followers 38.
One end of each arm member 32 slides in a direction relatively separated from the operation panel 62 to reduce the crossing angle α, and the other ends of the arm members 32 move in a direction in which they approach each other. The frame engaging members 20 move toward each other and the bellows 12 contract.

As described above, according to this embodiment, the operation panel 6
Since no means for forcibly urging the rotation of 2 in a certain direction is provided, the operation panel 62 can be easily rotated, and the bellows 12 can be manually rotated directly.
The amount of expansion and contraction of the bellows 12 can be easily roughly adjusted.

Further, in this embodiment, the bellows 12 is expanded and contracted by largely rotating the operation panel 62. 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 this embodiment, the expansion and contraction amount of the bellows 12 can be adjusted appropriately and easily by referring to the reference line 44 and the mark 61. If the mark 61 corresponds to the expansion / contraction amount of the lens that can be attached to the camera body, the expansion / contraction amount can be adjusted more appropriately and easily.

[0033]

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 mountable on the camera body.

[Brief description of drawings]

1 is a right side view when the bellows lens hood housing according to Kazumi施例of the present invention.

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 22a, 22b, 23a, 23b Roller guide groove 30 pantograph 32a-32d arm member 34a, 34b fulcrum roller 36a, 36b, 37a, 37b Guide roller 38a, 38b Cam followers 40 frame material 44a, 44b Reference line 46a, 46b Cam follower guide groove 50a, 50b Connecting member 56a, 56b Connection hole 60 Control 61a to 61d marks 70a, 70b Connecting member support shaft

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03B 11/04

Claims (5)

(57) [Claims] 1. An expansion / contraction mechanism of a bellows lens hood in which a front frame and a rear frame are elastically connected by a bellows, and a rotatable operation section, and a pantograph for elastically connecting the front frame and the rear frame. A cam follower provided on the pantograph, a guide means for guiding the cam follower in a direction substantially orthogonal to the expansion and contraction direction of the bellows, and a connecting member for connecting the cam follower with a position eccentric from the center of the operation portion. An expanding / contracting mechanism of a bellows lens hood, wherein the front frame and the rear frame are moved in an expanding / contracting direction of the bellows by rotating the operation portion. 2. The operation section is provided with a mark indicating the amount of expansion and contraction of the bellows corresponding to the lens attachable 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 guide means extends parallel to the front frame and the rear frame, and has a cam follower guide groove with which the cam follower slidably engages, and the pantograph has the cam follower guide groove formed therein. The expansion / contraction mechanism for the bellows lens hood according to claim 1, further comprising a frame member to which the operation portion is attached. 4. The pantograph has arm members connected to each other, and the cam followers are connected at a position that moves in a direction substantially orthogonal to a direction in which the bellows of the arm member expand and contract. The expansion / contraction mechanism of the bellows lens hood according to claim 1. 5. A front frame engaging member and a rear frame engaging member fixed to the front frame and the rear frame, respectively, and having roller guide grooves extending along the front frame and the rear frame, and the arm member. The expansion / contraction mechanism for the bellows lens hood according to claim 1, further comprising a guide roller provided and slidably engaged with the roller guide groove.