JPH059713Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a mounting device for a lens hood that is attached to the front part of a photographic lens barrel, and in particular a type of attachment device for tightening and fixing the lens hood to the outer periphery of the photographic lens barrel. This invention relates to improvements to lens hood attachment devices.

[Background of the idea]

A lens hood is usually removably attached to the front of a photographic lens barrel, but there are two ways to attach it: one is to screw it onto an attachment screw provided at the tip of the lens barrel, and the other is to attach it to the front of the lens barrel. Two methods are conventionally known: a method of attaching it to the outer periphery; and a method of attaching it to the outer periphery.
In addition, in the latter method, for example,
As disclosed in Japanese Patent No. 13659, the lens hood is fixed with a tightening screw after a fastener provided at the rear end of the lens hood is fitted to the outer periphery of the lens barrel. As shown in Japanese Patent No. 57-9913, a lens hood is known in which a protrusion on the inner circumference of the lens hood is engaged with and fixed in an engagement groove provided on the outer circumference of the tip of the lens barrel. .

Among the latter methods of attaching a lens hood to the outer periphery of the lens barrel, the method of fitting and fixing the lens hood to the lens barrel using a fastener as shown in Japanese Utility Model Publication No. 34-13659 requires a slight tightening screw. Even if it becomes loose, there is a risk of it falling off the lens barrel. Also,
The lens hood disclosed in Japanese Utility Model Application Publication No. 57-9913 has a structure that penetrates the cylindrical surface of the lens hood and is connected by a spring in order to engage the protrusion on the inner surface of the lens hood with the engagement groove of the lens barrel. The sliding piece, which is urged toward the center of the cylinder, is configured to engage with the engagement groove of the lens barrel from the side opposite to the lens hood protrusion. The hood attachment device of this publication is
Although it has the advantage that the hood can be easily attached and detached, it has a structure in which both sides of the engagement groove are formed with large slopes, and the sliding piece that engages with the groove is fixed by being biased by a spring. Therefore, if an external force is applied to the outer peripheral surface of the front end of the hood or near the spring, there is a risk that the hood will easily fall off from the lens barrel. In addition, since two protrusions that engage with the engagement grooves are formed on the inner circumference of the hood, they cannot be formed by machining alone.
After machining, other cutting operations such as milling or slotting are required, which not only complicates the machining process but also increases machining costs. Further, since the cylindrical portion of the lens hood is made of metal for strength, the protrusion that engages with the engagement groove is also made of the same metal as the cylindrical portion. Therefore, when the lens hood is attached or removed, the protrusion comes into contact with the outer periphery of the lens barrel, resulting in damage to the beautifully surface-treated outer periphery of the lens barrel.

[Purpose of invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens hood mounting device that solves the drawbacks of the conventional devices described above, is inexpensive as a whole, and can be mounted reliably without damaging the lens barrel.

[Summary of the invention] In order to achieve the above object, the present invention penetrates the circumferential surface of the hood cylinder 20 and slides toward the center of the cylinder in accordance with the rotational operation of the tightening knob 30, thereby forming grooves and walls. In a lens hood having a sliding piece 32 that can engage with the engagement groove 11 of the outer cylinder 10, one side of which is formed with a barrel attachment surface 13 perpendicular to the optical axis, the outer cylinder 10 has a small diameter portion 10b and a small diameter portion 10b on the distal end side of the outer cylinder 10. Large diameter portion 1 following small diameter portion 10b
0a, at least two first protrusion members 21A, 21B made of plastic material and capable of engaging with the engagement groove 11, and a second protrusion member 26A having a smaller protrusion amount than the first protrusion member. . 26A, 26B are disposed near the sliding piece 32 and on the same circumference as the first protruding members 21A, 21B, and are connected to the first protruding members 21A, 21B and the second protruding members 26A, 26B. an axis that is in contact with and eccentric from the central axis O of the hood cylinder 10 by a predetermined amount X;
The diameter D ₃ of the inscribed circle C centered on O' and the second
Diameter of inscribed circle E in contact with protruding members 26A and 26B
The technical point is to configure both _D4 to be smaller than the outer diameter _D2 of the large diameter portion 10a and larger than the outer diameter _D1 of the small diameter portion 10b.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is a - sectional view in FIG. 1. In FIGS. 1 and 2, an outer cylinder 10 at the tip of the lens barrel consists of a large diameter part 10a and a small diameter part 10b, and an engaging groove 1 is formed in the stepped part between them in the circumferential direction.
1 is formed. In the engagement groove 11, the groove wall on the left side in FIG. 1 is formed on the slope portion 12, and the groove wall on the opposite side (the right side in FIG. 1) is formed on the barrel surface 13 perpendicular to the optical axis. It is formed.

At the right end of the hood tube 20 in FIG. 1, there is a rectangular hole 20 through which a sliding piece 32 (described in detail later) passes.
A is provided on the inner surface of the hood cylinder 20,
A pair of first projection members 21 having the same thickness in the optical axis direction and formed by plastic molding.
A, 21B and a pair of second projection members 26A, 26B
and are fixedly fixed by taptight machine screws 29, respectively. Furthermore, these protruding members 21
A, 21B and 26A, 26B are spaced apart from each other (at 90° to each other) at positions that substantially divide the circumference into four equal parts, and the first protruding members 21A, 21B are connected to the rectangular hole 2.
It is provided within a semi-circumference opposite to the sliding piece 32 provided through 0A.

The first protruding members 21A, 21B have barrel mounting surfaces 24, 25 perpendicular to the optical axis on both sides in the optical axis direction, respectively, as shown in the cross-sectional view of FIG. 22 and 23 are provided symmetrically. Moreover, on the barrel attachment surface 13 of the outer cylinder 10,
As shown in FIG. 1, first protrusion members 21A, 21B
The side surface (body attachment surface) 25 of the outer cylinder 10 is in contact with the slope portion 12 of the engagement groove 11 of the outer cylinder 10, and the first projection member 21A,
The slope portion 22 of 21B is in contact with it. Furthermore, as shown in FIG. 5, the second projections 26A and 26B each have side surfaces 27, 28 perpendicular to the optical axis on both sides in the optical axis direction, and the cylindrical surfaces 27,
28 can also come into contact with the barrel attachment surface 13 of the outer tube 10 when the lens hood is attached.

The first protrusion member 21 has a high height h ₁ (see FIG. 3) and has a large protrusion from the inner circumferential surface of the hood cylinder 20.
A, 21B, the second protrusion member 26A, which has a low height h ₂ (see Fig. 5) and a small protrusion amount;
Inscribed circle C that is in contact with the inner peripheral surface of 26B (see Figure 2)
The diameter _D3 is larger than the small diameter portion _D1 of the outer cylinder 10,
It is formed smaller than the outer diameter _D2 of the large diameter part. The center O' of the inscribed circle C is eccentric by X in the direction of the rectangular hole 20A of the hood cylinder 20 from the hood cylinder center O, as shown in FIG. Furthermore, the diameter D ₄ of the inscribed circle E centered on the hood cylinder center O of the second projection members 26A, 26B is also the outer diameter D ₁ of the small diameter portion of the outer cylinder 10.
It is larger than the outer diameter D ₂ (see FIG. 1) of the large diameter portion.

On the other hand, a rectangular hole 20 is formed on the outer circumference of the hood cylinder 20.
A boss metal 31 is fixedly installed by a machine screw 34 over the boss metal 31, and a tightening knob 30 having a tightening screw 30A is screwed into the boss metal 31. Tightening screw 30
A sliding piece 32 is provided at the tip of A, and the sliding piece 32 is inserted into a hollowed-out groove 32A formed in the center part.
It is supported by a clip 33 through a through hole 32B communicating with the. Moreover, the sliding piece 32 is
The tightening knob 30 has a rectangular cross-sectional shape in a plane perpendicular to the axial direction, and is slidably fitted into the rectangular hole 20A of the hood cylinder 20. Furthermore, the sliding piece 32 is
The thickness of the projection members 21A, 21B, 26 in the optical axis direction is
It has barrel mounting surfaces 41 and 42 that are equal to A and 26B and perpendicular to the optical axis on both sides thereof, and slope portions 43 and 44 are symmetrically provided on the inner tip edge as shown in FIG. One of the barrel attachment surfaces 42 is the outer cylinder 10
, and one slope portion 43 is in contact with the slope portion 12 of the engagement groove 11 of the outer cylinder 10 .
The tip of the sliding piece 32 is located in the same plane perpendicular to the optical axis as the first protrusion members 21A, 21B, and its cross section is also the same as the first protrusion members 21A, 21B.
It is formed to have the same cross-sectional shape as 1B (see FIG. 3). In addition, the tightening knob 30 and the boss metal 31
Both of the slide piece 32 and the slide piece 32 can be molded from plastic, and the tightening mechanism thereof can be assembled as a unit and can be used for other lens hoods.

FIG. 4 shows the first projection member 21 shown in FIG.
6 is a side view of the second projection members 26A, 26B shown in FIG. 5. FIG. First protrusion members 21A, 21B with a large protrusion height h ₁ and second protrusion members 26A, 26 with a small protrusion height h ₂
The outer diameter _D5 of B is as shown in Figs. 4 and 6.
It is formed smaller than the diameter D ₆ of the inner peripheral surface of the hood cylinder 20 . Two center positions 51 of the prepared holes 50a for the taptight machine screws 29 when attaching the first projection members 26A, 26B to the inner circumferential surface of the hood cylinder 20.
Between a and 52a is a flank 5 parallel to the optical axis direction.
3a. That is, when the first protrusion members 21A and 21B are attached to the hood tube 20, the first protrusion members 21A and 21B are attached to the inner peripheral surface of the hood tube 20 through the lower holes 50a.
are in contact with each other at two central points 51a and 52a, and are fixed with tap-tight machine screws 29. Therefore, if the diameter D ₆ of the inner circumferential surface of the hood tube 20 is configured to satisfy the relationship D ₅ ≦D ₆ with the outer diameter D ₅ of the first projection members 21A, 21B, the inner circumferential surface of the hood tube 20 is Regardless of the diameter of the circumferential surface, the first protruding members 21A, 21B are fixed to the hood cylinder 20 without being deformed.

Similarly to the first protrusion members 21A and 21B, the second protrusion members 26A and 26B in FIG. A flank 63a is formed parallel to the axial direction. Therefore, also in this case, D ₅ ≦D ₆ exists between the diameter D ₆ of the inner circumferential surface of the hood cylinder 20 and the outer diameter D ₅ of the second projection members 26A, 26B.
If the structure is configured so that the following relationship holds true, the hood cylinder 2
Regardless of the diameter of the inner circumferential surface of 0, the second protruding member 26A,
26B can be fixed to the hood cylinder 20 without deformation.

Since the embodiment shown in FIG. 1 is constructed as described above, when attaching the hood tube 20 to the outer tube 10, the tightening knob 30 is rotated as shown in FIGS. 7 and 8. , a second protrusion member 26 whose tip end of the sliding piece 32 is fixed to the inner circumference of the hood cylinder 20
A, 26B from the inner circumferential surface (diameter D ₄ ) outward (7th
(upward in FIG. 8). At this time, since the sliding piece 32 is supported by the tightening screw 30a, it moves straight while being guided by the rectangular hole 20A. In this case, since the amount of movement of the sliding piece 32 matches the amount of upward movement of the tightening knob 30, the amount of movement of the sliding piece 32 depends on the vertical position of the tightening knob 30.
2 has been raised to a position where it can be installed.

When the tightening knob 30 is raised, the diameter _D3 of the inscribed circle C in contact with the first protruding members 21A, 21B and the second protruding members 26A, 26B becomes the outer diameter of the small diameter portion 10b of the outer barrel 10 of the lens barrel. D ₁ (see Figure 1), so as shown in Figure 7, the hood cylinder 20
It is possible to slightly eccentrically move it downward and move it in the optical axis direction to the position shown in FIGS. 7 and 8, and to cover the large diameter portion 10a of the outer cylinder 10. In this case, an inscribed circle C that is in contact with the first protruding members 21A, 21B and the second protruding members 26A, 26B on the inner circumference of the hood cylinder 20
and the diameter D ₄ of the inner circumferential circle E of the second projection members 26A, 26B are both the diameter D ₄ of the large diameter portion 1 of the outer cylinder 10.
Since the outer diameter D ₂ of the outer cylinder 10a is smaller than the outer diameter D 2 (see FIG. 1) and larger than the outer diameter D ₁ of the small diameter portion 10b, the first protruding members 21A and 21B do not interfere with the small diameter portion 10b of the outer cylinder 10. 1 protrusion members 21A, 21B
body mounting surface 25 and second protrusion members 26A, 26
The barrel mounting surface 28 of B contacts the barrel mounting surface 13 of the outer cylinder 10. Therefore, the hood tube 20 can be reliably positioned with respect to the outer tube 10 in the optical axis direction. Furthermore, since the first protruding members 21A, 21B and the second protruding members 26A, 26B abut against the body mounting surface 13 of the outer cylinder at positions that approximately divide the circumference into four, the hood cylinder 20 is brought into contact with the outer cylinder 12. It does not lean against.

Once the first protruding members 21A, 21B and the second protruding members 26A, 26B have come into contact with the barrel attachment surface 13 of the outer cylinder 10, the hood cylinder 20 is then slightly displaced upward, and the first protruding members Insert the tips of 21A and 21B into the engagement groove 11, and tighten the tightening knob 3.
Rotate 0. As the tightening knob 30 rotates, the tightening screw 30A moves forward (moves downward in FIG. 8), so the sliding piece 32 is guided by the rectangular hole 20A and moves straight, as shown in FIGS. It engages with the engagement groove 11 as shown in FIG. Furthermore, by sufficiently tightening the tightening screw 30A via the tightening knob 30, attachment of the lens hood to the outer tube 10 is completed.

By tightening the tightening knob 30, the first
The protruding members 21A, 21B and the sliding piece 32 are connected to the respective slope portions 22 and 43 and the slope portion 1 of the engagement groove 11.
2, it is reliably fitted into the engagement groove 11, and then the respective barrel attachment surfaces 25 and 42 come into close contact with the barrel attachment surface 13 of the outer cylinder 10. When the lens hood is attached, the hood tube 20 is supported at three points toward the optical axis center of the outer tube 10 by the first projection members 21A, 21B and the sliding piece 32. , the mounting is done stably. Moreover, since the sliding piece 32 does not move forward or backward unless the tightening knob 30 is rotated, the hood cylinder 2
0 is not displaced or tilted in the radial direction with respect to the outer cylinder 10.

Further, as is clear from FIGS. 1 and 2, the outer diameter D ₂ of the large diameter portion 10 a of the outer cylinder 10 is provided on the barrel attachment surface 13 of the outer cylinder 10 so as to protrude from the inner circumferential surface of the hood cylinder 20 . Since the inner diameter D ₄ of the second protrusion members 26A and 26B is larger than the inner diameter D 4 of the second projection members 26A and 26B, the force applied to the lens hood 20 in the thrust direction (rightward in FIG. , the respective trunk attachment surfaces 25 of the first projection members 21A and 21B, and the second projection members 21A and 21B.
Each barrel attachment surface 28 of the projection members 26A, 26B
Since it is received at five points on the body attachment surface 42 of the sliding piece 32, the protruding members 21A, 21B, 26A,
There is no risk that 26B or the sliding piece 32 will be deformed or damaged. In addition, the protrusion members 21A, 21B, 26A, 2
6B is formed separately from the hood tube 20, so that the inner peripheral portion of the hood tube 20 can be completed by only machining, reducing processing costs.
Furthermore, the first protruding members 21A, 21B have a body attaching surface 25, the second protruding members 26A, 26B's body attaching surface 28, and the sliding piece 32's body attaching surface 42 are in a line perpendicular to the axis of the hood tube 20. Since it is on a flat surface, the body mounting surface 13 of the outer cylinder that is in contact with this can also be formed only by machining. Further, when the lens hood is attached, the hood tube 20 does not tilt with respect to the lens barrel.

When removing the lens hood from the outer diameter 10, first reverse the tightening knob 30 and remove the sliding piece 32.
is retracted to the position shown in FIGS. 7 and 8. Next, after displacing the hood cylinder 20 slightly downward, and further moving it to the left in FIG. 7, the outer cylinder 1
You can remove the lens hood from 0.

Further, the lens hood of the above embodiment is configured as a so-called cover-type lens hood. That is, since the first protruding members 21A, 21B, the second protruding members 26A, 26B, and the sliding piece 32 are all formed to have symmetrical cross-sectional shapes in the optical axis direction,
When the lens hood is not in use, it can be attached to cover the outer cylinder with the lens hood reversed from front to back (left and right in reverse directions in FIG. 1). In this case, the operation method for mounting and dismounting and the mounting situation are almost the same as in the case of the forward direction. With the sliding piece 32 retracted, the hood tube 20 is placed over the outer tube 10 from the front end (left end in FIG. 1) of the hood tube 20 and moved to the right in the optical axis direction. Projection member 21
Once the barrel attachment surfaces 24 of each of A and 21B and the barrel attachment surface 27 of each of the second projection members 26A and 26B come into contact with the barrel attachment surface 13 of the outer cylinder 10, the tightening knob 30 is rotated to slide. The piece 32 may be moved forward to cause the slope portion 44 of the sliding piece 32 to come into pressure contact with the slope portion 12 of the engagement groove 11. In addition, also in this case, the body attachment surfaces 24 of the first protrusion members 21A, 21B, the body attachment surfaces 27 of the second protrusion members 26A, 26B, and the sliding piece 32
The barrel attaching surface 41 is placed within a plane perpendicular to the axis of the hood tube 20, and the barrel attaching surface 13 of the outer tube 10
Since the hood cylinder 20 contacts the outer cylinder 10 at five points, the hood cylinder 20 is mounted without being inclined with respect to the outer cylinder 10 and without being eccentric as shown in FIG. In this case as well, unless the tightening knob 30 is rotated, the tightening will not loosen, so even if an external force is applied to the hood tube 20, the hood tube 20 will not be dismounted or tilted. In addition, the first protrusion member 2
1A, 21B, second protrusion members 26A, 26B,
Since it is made of plastic, the outer cylinder 1
When attaching the lens hood to the lens hood, the protruding member 21 is attached to the small diameter portion 10b of the outer cylinder 10 and the barrel mounting surface 13.
Even if A, 21B, 26A, and 26B come into contact with each other, the outer surface of the outer cylinder 10 will not be damaged.

In the above embodiment, the second protruding members 26A and 26B are provided as a pair with the sliding piece 32 in between, but only one second protruding member may be used as long as it is near the sliding piece 32.

[Effect of idea]

As described above, according to the present invention, when the lens hood is placed over the outer periphery of the lens barrel, one side surface (body attachment surface) of each of the first protrusion member, the second protrusion member, and the sliding piece is Since it is in close contact with the barrel attachment surface of the engagement groove on the lens barrel side, the lens hood can be reliably positioned in the thrust direction, and there is no fear that the lens hood will be installed at an angle. In addition, after installation, the protruding member and the sliding piece will allow at least 3
Since the lens hood is supported by a point, radial positioning is reliable, the lens hood will not wobble against the lens barrel, and even if an external force is applied to the lens hood, the lens will not move as long as the tightening knob is not turned. The hood will not fall off carelessly. Furthermore, since all of the protruding members are configured to be attached and fixed to the inner circumferential surface of the hood, it is not only easy to process the inner circumferential surface of the hood, but also the protruding members can be formed in plastic mode, reducing manufacturing costs. I can,
Moreover, there is no risk of damaging the lens barrel during installation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention installed in a lens barrel, FIG. 2 is a cross-sectional view taken from FIG. 1, and FIG. 4 is an enlarged sectional view of the first protrusion member shown in FIG. 3, FIG. 5 is an enlarged sectional view of the second protrusion member shown in FIG. 1, and FIG. 6 is a side view of the first protrusion member shown in FIG. FIG. 7 is a side view of the protruding member, FIG. 7 is a vertical cross-sectional view showing a state before attachment in which the lens hood and lens barrel shown in FIG. 1 are eccentric, and FIG. 8 is a cross-sectional view taken from FIG. 7. Explanation of symbols of main parts, 11...Engagement groove, 13
...Body mounting surface, 20...Hood cylinder, 21A, 21B
...First protrusion member, 26A, 26B...Second protrusion member, 30...Tightening knob, 32...Sliding piece.

Claims (1)

[Claims for Utility Model Registration] (1) A groove that penetrates the circumferential surface of the hood cylinder 20 and slides toward the center of the cylinder in response to the rotation of the tightening knob 30, with one of the grooves and walls perpendicular to the optical axis. Body attachment surface 13
In a lens hood having a sliding piece 32 that can be engaged with the engagement groove 11 on the outer periphery of the outer cylinder 10, the outer cylinder 10 has a small diameter part 10b on the distal end side and a large diameter part 10a following the small diameter part 10b. At least two first protruding members 21A, 21B made of plastic material and capable of engaging with the engagement groove 11, and second protruding members 26A, 26B having a smaller protrusion amount than the first protruding members. are fixed to the inner circumferential surface of the hood cylinder, the first protruding members 21A, 21B are spaced apart within a semicircle facing the sliding piece 32, and the second protruding members 26A, 26B is near the sliding piece 32 and the first protruding member 21
A, 21B are disposed on the same circumference, and the first projection members 21A, 21B and the second
A shaft that is in contact with the protrusion members 26A and 26B and is eccentric by a predetermined amount X from the central axis O of the hood cylinder 10.
The diameter D ₃ of the inscribed circle C centered on O' and the diameter D ₄ of the inscribed circle E in contact with the second projection members 26A, 26B are both the outer diameter D ₂ of the large diameter portion 10a.
and the outer diameter D ₁ of the small diameter portion 10b
A lens hood attachment device characterized by having a larger structure. (2) The first projection members 21A, 21B and the second
The protruding members 26A and 26B are each fixed by two taptight machine screws 29, and the mounting surfaces in contact with the inner circumferential surface of the hood cylinder 20 are provided with prepared holes 50a and 6a into which the taptight machine screws 29 are inserted.
The lens hood mounting device according to claim 1, wherein the lens hood mounting device is formed so as to escape except in the vicinity of the lens hood.