JPH0562965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hood attachment mechanism for attaching a photographic lens hood to a photographic lens.

[Prior Art and its Problems] Three types of attachment mechanisms for photographic lens hoods have been proposed: a screw-in type, a bayonet type, and a peripheral spring-loaded type.

The screw-in type is a type in which a screw is cut at the joint between the hood and the lens barrel, and although the hood can be securely attached to the lens, the manufacturing cost is high, it is time-consuming to attach and remove it, and it is difficult to fit the screw properly. There are some drawbacks that make it unusable as a photographic lens. Furthermore, the bayonet type uses something similar to a bayonet type mount for attaching an interchangeable lens to the camera body, but the mechanism is extremely complicated and the manufacturing cost is extremely high. The outer periphery spring push type uses a spring material between the outer periphery of the lens barrel and the hood, and uses the restoring force of the spring to attach the hood to the lens barrel. Although it has the advantage of being able to be attached to any photographic lens, conventional ones have a complicated structure of the spring part used, and tend to be expensive to manufacture. In the end, there is no conventional lens hood that satisfies both ease of installation and removal and manufacturing cost.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photographic lens hood attachment mechanism that is easy to install and remove, and can be manufactured at low cost.

[Means for Solving the Problems] The hood attachment mechanism according to the present invention includes first and second horseshoe-shaped members each having two arms. At the tip of the arm, there is a claw that protrudes inside the horseshoe shape. Further, an operating knob that projects outward is provided at the center of the horseshoe-shaped arc. On the other hand, on the back surface of the stationary cylinder of the cylindrical hood attached to the photographic lens, a ring-shaped groove for accommodating the horseshoe-shaped plate member is provided at the periphery of the central cylindrical shaft portion. When the plate member is stored in the inner peripheral wall of this groove,
A notch into which the claw is loosely fitted, and a notch into which the operating knob is fitted are formed in the outer peripheral wall of the groove at corresponding positions.

The first and second horseshoe-shaped plate members are arranged to face each other so that their respective arms intersect with each other, and a small hole is bored in one arm of each overlapping arm portion, while a pin is planted in the other arm. When this pin is inserted into the small hole to connect both plate members and placed in the groove, the tips of each claw and each operation knob protrude outward from the peripheral wall through their respective notches and are housed. It was to so. As a result, the claw at the tip of the arm engages with the outer surface of the photographing lens barrel, and the hood is attached to the lens.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1A is a rear view of the two-stage retractable hood viewed from the rear, that is, from the photographing lens side, with a portion cut away. In FIG. 1B, the upper half shows a central vertical cross-sectional view of the two-tiered hood in an extended state, and the lower half shows a side view of the two-tiered hood in a retracted state.

Hood 10 illustrated in FIGS. 1A and 1B
is a cylindrical hood main body 12 and a hood main body 12
and an attachment mechanism 50 for attaching the lens to the photographic lens. Further, the hood main body 12 includes a stationary cylinder 12A having the attachment mechanism 50 installed at the end on the photographing lens side, and a movable cylinder 12B that slides along the stationary cylinder 12A. This stationary cylinder 12A
A rear view of the device is shown in FIG. 2A, and a cross-sectional view taken along line BB in FIG. 2A is shown in FIG. 2B. As clearly shown in FIG. 2A, the back surface of the stationary cylinder 12A is open at the central cylindrical shaft portion and has a ring-shaped groove 14 on the periphery. The wall 16 on the outer peripheral side of the groove 14 is provided with notches 16A and 16B at two locations in the diametrical direction. Although details will be described later, this notch 16A,
16B, operation knobs 54A, 54 of the mounting mechanism 50
B is inserted into each. Further, the wall 18 on the inner peripheral side of the groove 14 is provided with notches 19, 20, 21, and 22 at four locations spaced apart along the circumference.
As seen in FIG. 2A, the cutout 16B is the cutout 1
Located in the middle direction between 9 and 20, notch 16A
is located in the middle direction between the notches 21 and 22.
Preferably, the notches 19 and 21 and the notches 20 and 22 are on a diameter passing through the central axis of the cylinder 16A.

The attachment mechanism 50 includes two horseshoe-shaped plate members 52.
It consists of A and 52B. A plan view of this horseshoe-shaped member 52B is shown in FIG. 3A, and a side view thereof is shown in FIG. 3B. The horseshoe-shaped member 52B has an arc shape extending approximately 270 degrees as a whole, and is provided with an operating knob 54B projecting outward on the outside of the central part of the arc.
At both arc ends of the horseshoe-shaped member 52B, claws 56B and 58B that protrude inside the horseshoe shape are provided, and an arm portion 60 between the claws 56B and the operation knob 54B is provided.
A small hole 6 is located approximately 90 degrees from the operation knob 54B.
2B, open the other tab 58B and operation knob 54B.
A pin 66B is installed at about 90 degrees from the operating knob 54B in the arm portion 64B between the two.

Horseshoe shaped member 52A has exactly the same shape as horseshoe shaped member 52B.

Positions 62B, 66B of one horseshoe-shaped member 52B
Small holes may be provided in both, and pins that fit into these small holes may be provided at corresponding positions on the other horseshoe-shaped member 52A.

As can be seen in FIG. 1A, one arm 60B of the second horseshoe-shaped member 52B rests on one arm 64A of the first horseshoe-shaped member 52A in the groove 14 of the cylinder 12A, and the second horseshoe-shaped member 5
The other arm 60A of the first horseshoe member 52A rides on the other arm 64B of the first horseshoe member 52A. and,
The pin 66B of the horseshoe-shaped member 52B is connected to the horseshoe-shaped member 52.
Fits into the small hole 62A of the arm 60A of A, and on the other hand,
Pin 66A of arm 64A of horseshoe member 52A fits into small hole 62B of arm 60B of horseshoe member 52B. The operating knob 54A fits into the notch 16A, and the operating knob 54B fits into the notch 16B. The claw 56A is in the notch 20, the claw 56B is in the notch 22, the claw 58A is in the notch 19,
The claw 58B fits into the notch 21, and these claws 56A, 56B, 58A, 58B protrude from each of the notches 19, 20, 21, 22 into the space 70 inside the cylinder in their natural state. In such a natural state, the claws 56A, 56B, 58A, 58
The sizes of the claws 56A, 56B, 58A, and 58B are designed so that the lens B can clamp the photographic lens with a desired clamping force. However, if grooves into which the claws 56A, 56B, 58A, and 58B fit are provided on the side surface of the photographic lens barrel, it is sufficient that the tabs can be fitted into the grooves.

In this way, after inserting both horseshoe-shaped members 52A and 52B into the groove 14, a ring-shaped cover 72 is placed on top of them.
to seal the concave groove 14.

In this way, by intersecting and opposing the first horseshoe-shaped member 52A and the second horseshoe-shaped member 52B, the claws 56B of the horseshoe-shaped member 52B and the horseshoe-shaped member 52, which face each other with the central axis of the cylindrical hood in between,
The claw 56A of A is located in the same plane perpendicular to the central axis of the hood. Similarly, horseshoe shaped member 52B
claw 58B and a horseshoe-shaped member 52A opposite thereto.
The claws 58A are also in the same plane perpendicular to the central axis of the hood. The photographing lens (not shown) is No. 1A.
Although it is inserted into the central space 70 in the figure, it is held between the claws 56A and 56B and the claws 58A and 58B, so the opposing claws 56
Since A, 56B, 58A, and 58B are in the same plane, the hood attached to the photographic lens does not tilt with respect to the optical axis of the photographic lens.

Since the two horseshoe-shaped members 52A, 52B are integrated by fitting the pins 66A, 66B into the small holes 62A, 62B, both operating knobs 54A, 54B
When you try to push the pin inward to bring them closer together, the fitting part of this pin and the small hole moves a little outward of the cylinder, and the claws 56A, 56B, 58A, 58B are notched, and the 1
9, 20, 21, 22 and evacuates from the space 70. Then, the photographing lens is inserted into the space 70, and the operation knobs 54A, 54B are released. Then, the claws 56A, 56B, 58A, and 58B return to the inside of the cylinder, and the hood 10 is attached to the photographic lens. When removing the hood 10 from the photographic lens, the operation is the opposite.

In the above embodiment, two horseshoe shaped members 52A, 5
2B have exactly the same shape, fewer types of parts are required, and assembly and manufacturing costs can be lowered.

[Effects of the Invention] As can be seen from the above explanation, the hood attachment mechanism according to the present invention consists of an extremely small number of parts.
It is easy to assemble and can be manufactured at low cost. Moreover,
The operability of attaching to and detaching from the photographic lens is no different from that of the conventional outer periphery spring-pressing type, and is extremely good.

[Brief explanation of the drawing]

Fig. 1A is a partially cutaway rear view of a hood that employs the hood attachment mechanism of the present invention, Fig. 1B is a view showing both a central sectional view and a side view of the hood, and Fig. 2A is the hood main body. FIG. 2B is a sectional view taken along the line B--B of FIG. 2A, FIG. 3A is a plan view of parts of the attachment mechanism of the present invention, and FIG. 3B is a side view thereof. 10...Hood 12...Hood body 12A
...Stationary cylinder 12B...Sliding cylinder 14...Concave groove 16...Outer wall 16A, 16B...Notch 18...Inner wall 19, 20, 21, 22...Notch 50...Mounting mechanism 52A, 52B... …
Horseshoe-shaped member 54A, 54B...operation knob 56
A, 56B, 58A, 58B...Claw 60A,
60B, 64A, 64B...Arm 62A, 6
2B...Small hole 66A, 66B...Pin 70...
...Space 72...Cover.

Claims (1)

[Scope of Claims] 1. A mounting mechanism 50 provided on the hood for mounting the cylindrical hood to a photographic lens, comprising first and second horseshoe-shaped plates comprising two arms 60A, 64A; 60B, 64B. Members 52A, 52B
and a ring-shaped groove 14 provided on the periphery of the central cylindrical shaft portion on the back surface of the stationary cylinder 12A of the cylindrical hood and housing the horseshoe-shaped plate members 52A, 52B, and the arms 60A, 64A;
0B, 64B are provided with claws 56A, 58A; 56B, 58B that project inwardly in a horseshoe shape, and operation knobs 54A, 54B that project outwards are provided in the arc center portion of the horseshoe shape.
When the plate members 52A, 52B are stored in the inner peripheral wall 18 of No. 4, the tabs 56A, 58A; 56B, 5
The notches 19, 20, 21, 22 into which the knobs 8B are loosely fitted are placed in corresponding positions, and the notches 16A, 16B into which the operating knobs 54A, 54B are fitted are placed in the outer peripheral wall 16 of the concave groove.
are in concave contact with corresponding positions, respectively, and the first and second
The horseshoe-shaped plate members 52A and 52B are attached to each arm 60.
A, 64A; 60B, 64B are made to face each other so as to cross each other, and small holes 62A, 62B are bored in one arm of each overlapping arm portion, while pins 66A, 66B are planted in the other arm; The pins 66A, 66B are fitted into the small holes 62A, 62B to connect the plate members 52A, 52B, and the groove 14
When placed inside, each claw 56A, 58A; 56
A photographic lens hood mounting mechanism characterized in that the tips of the operating knobs 54A, 54B and the operating knobs 54A, 54B protrude outward from the peripheral walls 16, 18 through respective notches and are housed therein. 2 The first and second two horseshoe-shaped plate members 52
The photographing lens hood attachment mechanism according to claim 1, wherein A and 52B have the same shape.