JP3548265B2 - Lens barrier mechanism - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a lens barrier mechanism for protecting a lens of a camera or the like.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in a compact camera or the like, instead of a lens cover of a camera, a lens barrier mechanism that is attached to the tip of a shooting lens barrel and opens and closes a shooting opening is used.
In general, a lens barrier mechanism has a plurality of barrier blades. Normally, a pair of barrier blades is driven by a motor, and another pair of driven barrier blades is driven by the motor to form two pairs of barrier blades. It is configured to open and close.
In the conventional lens barrier mechanism, a barrier drive ring that is rotatable within the lens barrel is provided, and when the barrier blade is opened, a projection provided on the barrier drive ring comes into contact with a boss formed on the barrier blade. When the barrier blade is rotated to the open position and the barrier blade is closed, the urging of the boss by the projection of the barrier drive ring is released, and the barrier blade returns to the closed position by the urging of the torsion spring. Met.
[0003]
[Problems to be solved by the invention]
However, in the conventional lens barrier mechanism, when an external force is applied due to an erroneous operation, such as when the barrier blade during the opening operation is pressed by hand, damage to parts such as a projection of the barrier drive ring and a boss of the barrier blade is caused. There was a case to invite.
In addition, the conventional lens barrier mechanism has a drawback in that the opening and closing failure of the barrier blade tends to occur due to the dimensional variation of the projection of the barrier drive ring and the boss of the barrier blade.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens barrier mechanism that prevents damage to components at the time of erroneous operation and prevents occurrence of opening and closing failure of barrier blades.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a camshaft having a support shaft rotatably holding a driving blade, a boss formed at an end of the driving blade, a groove for fitting the boss, and a cam member. , A first elastic means for constantly biasing the first end of the cam member in a first direction with respect to the drive member, and a second end of the cam member with respect to the drive member. When the boss moves in the first direction, the driving blade rotates about the support shaft in a direction to open the opening, and the boss moves in the first direction. Is moved in the second direction, the driving blade rotates around the support shaft in a direction to close the opening, and the driving member drives the cam member in the direction in which the first end approaches the boss. The boss moves in the first direction, and the driving member drives the cam member in a direction in which the second end approaches the boss. By, wherein the boss is moved in the second direction.
Further, a configuration is also possible in which the plurality of blades are at least one driving blade and at least one driven blade, and the driven blades move between the open position and the closed position by engaging with the driving blades. Further, the driving member may be a driving ring that slides inside the camera barrel, and the first direction may be a direction toward the outer periphery of the front driving ring, and the second direction may be a direction toward the inner periphery of the driving ring. It is. Further, a configuration in which the elastic member is a torsion spring, a hook portion that engages with the torsion spring at both ends of the cam member, and a configuration in which the support shaft is a projection formed on a decorative plate is also possible.
[0006]
【Example】
Hereinafter, the present invention will be described based on examples. FIG. 1 is an exploded perspective view showing a main part of a lens barrier mechanism according to the present invention.
A decorative plate 10 is provided at the leading end of the taking lens. The decorative plate 10 is fixed to the lens barrel 100 and has a photographing opening 11. First barrier blades 40 and 50 and second barrier blades 62 and 64 are provided on the camera body side of the decorative plate 10, and a barrier mounting plate 20 is provided on the camera body side. This barrier mounting plate 20 is fixed to the decorative plate 10.
[0007]
Of the first barrier blades 40 and 50 and the second barrier blades 62 and 64, the first barrier blade 40 and the second barrier blade 62 are rotatably supported by the support shaft 12 provided on the decorative plate 10, The blade 50 and the second barrier blade 64 are provided on the decorative plate 10 and are rotatably supported by the support shaft 14. The tips of the support shaft 12 and the support shaft 14 are fitted into the barrier mounting plate 20, whereby the first barrier blades 40 and 50 and the second barrier blades 62 and 64 are moved between the decorative plate 10 and the barrier mounting plate 20. Is rotatably supported.
[0008]
When the opening 11 is opened, the first barrier blade 40 and the second barrier blade 62 and the first barrier blade 50 and the second barrier blade 64 are set so as to overlap each other in the optical axis direction. When closing the opening 11, the first barrier blades 40 and 50 close the center of the opening 11, and the second barrier blades 62 and 64 close the periphery of the portion where the first barrier blades 40 and 50 close. It is set as follows.
[0009]
The second barrier blade 62 is provided with an engaging portion 65 and a projecting portion 66. When the first barrier blade 40 rotates in the closing direction, the contact portion 45 provided at the tip of the first barrier blade 40 comes into contact with the protrusion 66 of the second barrier blade 62, and the second barrier blade 62 is moved in the closing direction. To rotate. When the first barrier blade 40 rotates in the opening direction, the contact side 46 of the first barrier blade 40 comes into contact with the engaging portion 65 of the second barrier blade 62, and the second barrier blade 62 rotates in the opening direction. . In this way, the second barrier blade 62 follows the first barrier blade 40. Similarly, the second barrier blade 64 is driven by the first barrier blade 50.
[0010]
Since the second barrier blades 62 and 64 are driven by the first barrier blades 40 and 50, the opening and closing operation of the first barrier blades 40 and 50 will be described below. For simplicity, the first barrier blades 40, 50 are simply referred to as barrier blades 40, 50.
[0011]
First, the barrier drive ring 30 will be described with reference to FIGS. As shown in FIG. 1, the barrier drive ring 30 is slidably supported between the barrier mounting plate 20 and the lens barrel 100. A gear part 34 is formed on a part of the barrier drive ring 30, and the gear part 34 meshes with a pinion 102 provided in the lens barrel 100. The pinion 102 is driven by a motor (not shown), and the rotation of the pinion 102 causes the barrier drive ring 30 to rotate.
[0012]
As shown in FIG. 2, cam members 70 and 80 are provided on the barrier drive ring 30. Inner wall portions 345 and 346 are formed near the inner periphery of a portion of the barrier drive ring 30 where the cam members 70 and 80 are arranged. Since the cam members 70 and 80 have a symmetrical shape, the cam member 70 will be described here. The cam member 70 has an arc shape, and the outer arc has the same curvature as the outer circumference of the barrier drive ring 30, and the inner arc has the same curvature as the inner wall 345 of the barrier drive ring 30. A groove 77 is formed in the center of the cam member 70. Further, hook portions 71 and 73 and slide portions 72 and 74 are formed at both ends of the cam member 70.
[0013]
FIG. 3 shows a perspective view of the cam member 70. As shown in FIG. 3, a positioning boss 75 for positioning is formed at an end of the groove 77 of the cam member 70 closer to the hook 73. The positioning boss 75 is inserted into a positioning slot 314 formed in the barrier drive ring 30, as shown in FIG.
Further, the cam member 70 is provided with a falling-off preventing portion 78, which is engaged with a falling-off preventing opening 324 formed on the barrier drive ring 30. Further, as shown in FIG. 3, a recess 79 is formed in the groove 77 of the cam member 70.
[0014]
Torsion springs 94 and 93 are attached to both sides of the cam member 70 of the barrier drive ring 30. The torsion spring 94 is supported by a spring support member 334 provided on the barrier drive ring 30, and fixes one end on the inner peripheral side of the barrier drive ring 30 to the barrier drive ring 30. The other end of the torsion spring 94 engages with the hook portion 71 of the cam member 70 or slidably contacts the slide portion 72 depending on the position of the cam member 70. The torsion spring 93 is supported by a spring support member 333 provided on the barrier drive ring 30, and has one end on the outer peripheral side of the barrier drive ring 30 fixed to the barrier drive ring 30. The other end of the torsion spring 93 engages with the hook portion 73 of the cam member 70 or slidably contacts the slide portion 74 depending on the position of the cam member 70.
[0015]
With the above-described configuration, the cam member 70 can be moved in a range from a position where the cam member 70 contacts the inner wall portion 345 to a position where the fall prevention portion 78 contacts the edge of the fall prevention opening 324. The end of the cam member 70 on the hook portion 71 side is urged toward the outer periphery of the barrier ring 30, and the end on the hook portion 73 side is urged toward the inner periphery of the barrier drive ring 30. .
Similarly, the cam member 80 can be moved within a range from a position where the cam member 80 contacts the inner wall portion 346 to a position where the fall prevention portion 88 contacts the fall prevention opening 322. The end on the hook part 81 side is urged toward the outer periphery of the barrier ring 30, and the end on the hook part 83 side is urged toward the inner periphery of the barrier drive ring 30.
In this manner, the positions of the cam members 70 and 80 with respect to the barrier drive ring 30 are regulated in the circumferential direction of the barrier drive ring 30 by the positioning bosses 75 and 85, and the cam members 70 and 80 move in the radial direction of the barrier drive ring 30. It becomes possible.
[0016]
Next, a driving method of the barrier blades 40 and 50 will be described. FIG. 4 is a front view from the position A in FIG. 1 when the barrier blades 40 and 50 are in an open state. Since the driving method of the barrier blade 40 and the barrier blade 50 is the same, the barrier blade 50 will be described here.
A boss 51 is protruded from the tip of the barrier blade 50. The boss 51 penetrates the hole 22 formed in the barrier mounting plate 20 and is inserted into the groove 77 of the cam member 70. Note that the barrier blade 50 is rotatable around a rotation hole 52 provided adjacent to the boss 51.
[0017]
As shown in FIG. 4, when the barrier blade 50 is in the open position, the cam 70 has the hook portion 73 in contact with an inner wall recess 344 provided near the inner periphery of the barrier drive ring 30, and the hook portion 71 is The drop prevention portion 78 of the cam member 70 is located closer to the outermost periphery of the cam 30 and contacts the drop prevention opening 324 of the barrier drive ring. The torsion spring 94 is engaged with the hook 71, and the torsion spring 93 is slidably abutted on the slide 74.
[0018]
When the barrier drive ring 30 rotates clockwise in the figure from this state, the cam member 70 moves in the circumferential direction of the barrier drive ring 30 by the engagement between the positioning boss 75 and the positioning slot 314. Accordingly, the boss 51 moves rightward in the drawing, that is, toward the outside of the barrier drive ring 30 along the groove 77 of the cam member 70. Accordingly, the barrier blade 50 rotates clockwise in the figure around the rotation hole 52.
[0019]
The barrier drive ring 30 further rotates slightly after the barrier blade 50 reaches the closed position, and stops when it reaches the position shown in FIG. After the barrier blade 50 reaches the closed position, the barrier drive ring 30 further rotates slightly, so that the cam member 70 shifts its hook portion 71 side slightly inside the barrier drive ring 30, and The 73 side is slightly shifted to the outside of the barrier drive ring 30. As a result, the hook portion 73 and the inner wall concave portion 344 are separated, and the drop-off preventing portion 78 and the drop-off preventing opening 324 are also separated. That is, the position of the cam member 70 is regulated only by the torsion springs 94 and 93.
[0020]
When moving from the closed position to the open position, the barrier drive ring 30 rotates counterclockwise in the figure, and the boss 51 moves along the groove 77 formed in the cam member 70 to the left in the figure, that is, the barrier drive ring 30. Move toward the inside. As a result, the barrier blade 50 rotates counterclockwise in the figure around the rotation hole 52. The barrier drive ring 30 further rotates slightly after the barrier blade 50 reaches the open position, and stops when it reaches the position shown in FIG.
With the above configuration, the opening and closing operation of the barrier blade 50 is performed. The opening / closing operation of the barrier blade 40 is performed similarly.
[0021]
Here, the operation of the barrier blade 50 in the case of an erroneous operation or the like will be described.
First, it is assumed that the barrier blade 50 is pressed by hand during the transition from the closed state to the open state in FIG. Since the barrier blade 50 is pressed, the position of the boss 51 does not change even if the barrier drive ring 30 rotates clockwise in the figure, but the hook portion 73 side of the cam member 70 resists the urging force of the spring 93. Then, since it moves toward the outside of the barrier drive ring 30, there is no damage to the components. Further, even if the finger pressed in this state is suddenly released, the barrier blade 50 returns to the original position by the urging force of the spring 93, and in this case, there is no damage to the components.
[0022]
Also, when the barrier blade 50 is pressed by hand during the transition from the open state to the closed state in FIG. 4, the cam member 70 has the hook portion 71 inside the barrier drive ring 30 against the urging force of the spring 94. , So there is no damage to the parts. Further, even if the finger pressed in this state is suddenly released, the barrier blade 50 returns to the original position due to the urging force of the spring 94, and in this case, there is no damage to the components.
[0023]
When the barrier blade 50 is to be opened by hand in the closed state of FIG. 5, the hook portion 71 side of the cam member 70 is positioned inside the barrier drive ring 30 against the urging force of the spring 94. , The parts can be prevented from being damaged.
As described above, the lens barrier mechanism according to the present invention can prevent parts from being damaged by an external force against the operation of the blade such as an erroneous operation.
[0024]
Next, the opening and closing failure of the barrier blade will be described.
In a conventional barrier drive ring, due to dimensional variations of components such as bosses of barrier blades, when the barrier blades are closed, a gap is formed between the barrier blades, so-called open / close remaining sometimes occurs. However, in the lens barrier mechanism according to the present invention, even when the dimension of the boss 51 of the barrier blade 50 is smaller than the design value, the hook 94 side of the barrier drive ring 70 is further urged toward the outer periphery by the spring 94 and moves. Therefore, there is no gap between the closed barrier blades 40 and 50.
[0025]
Next, the assembling work of the cam member 70 and the springs 93 and 94 will be described. As shown in FIG. 3, since an opening is formed on the side of the slide portion 72, 74 of the cam member 70 facing the torsion spring 94, 93, one end of the torsion spring 94, 93 is connected to the slide portion 72, 74. Can be easily performed.
[0026]
Further, the barrier blocks having the first barrier blades 40 and 50 and the second barrier blades 62 and 64 mounted between the decorative plate 10 and the barrier mounting plate 20 are connected to the cam members 70 and 80 and the torsion springs 91, 92, 93 and 94. Since the recesses 79 and 89 are formed in the grooves 77 and 87 of the cam members 70 and 80 at the time of assembling with the barrier drive ring 30 to which the bosses 41 and 51 are attached, the bosses 41 and 51 are easily fitted into the cam members 70 and 80. .
[0027]
【The invention's effect】
As is apparent from the above description, in the present invention, since the barrier blade is opened and closed by the cam member attached to the barrier drive ring via a spring, there are obstacles that hinder the operation of the barrier blade, such as erroneous operations when opening and closing the barrier. However, it is possible to prevent the parts from being damaged. Further, it is possible to prevent the barrier blade from being opened and closed in a case where there is a variation in the dimensions of the components. In addition, since the portion of the cam member that engages with the spring is an opening, and the concave portion is formed in the groove of the cam member, the operation of assembling the spring and the cam member on the barrier drive ring and the operation of assembling the barrier blades are simplified. become.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a lens barrier mechanism according to an embodiment of the present invention.
FIG. 2 is a front view showing a barrier drive ring and a cam member according to the embodiment of the present invention.
FIG. 3 is a perspective view showing a cam member according to the embodiment of the present invention.
FIG. 4 is a front view showing a lens barrier mechanism according to the embodiment of the present invention.
FIG. 5 is a front view showing a lens barrier mechanism according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Decorative plate 20 Barrier mounting plate 30 Barrier drive ring 40, 50 First barrier blade 41, 51 Boss 62, 64 Second barrier blade 70, 80 Cam member 71, 73 Hook portion 79, 89 Fall prevention portion 81, 83 Slide portion 75, 85 Positioning bosses 91, 92 Torsion springs 93, 94 Torsion springs 100 Lens barrels 312, 314 Positioning long holes 322, 324 Dropout prevention openings

Claims (6)

A lens barrier mechanism for a camera having a plurality of blades for opening and closing a shooting aperture of a shooting lens, wherein the plurality of blades includes at least one drive blade.
A spindle for rotatably holding the driving blade,
A boss formed at an end of the driving blade;
A cam member having a groove for inserting the boss,
A driving member for driving the cam member;
A first torsion spring that constantly biases a first end of the cam member in a first direction with respect to the drive member;
A second torsion spring that constantly biases a second end of the cam member in a second direction with respect to the drive member,
When the boss moves in the first direction, the drive blade pivots around the support shaft in a direction to open the opening, and when the boss moves in the second direction, the drive blade Rotate around the support shaft in the direction to close the opening,
The driving member drives the cam member in a direction in which the first end approaches the boss, whereby the boss moves in the first direction,
A lens barrier mechanism for a camera, wherein the driving member drives the cam member in a direction in which the second end approaches the boss, whereby the boss moves in the second direction. . The plurality of blades include at least one driving blade and at least one driven blade, and the driven blade is moved between an open position and a closed position by engaging with the driving blade. The lens barrier mechanism of the camera according to claim 1, wherein the lens barrier mechanism is provided. The lens barrier mechanism for a camera according to claim 1, wherein the driving member is a driving ring that slides in a camera barrel. The camera lens according to claim 3, wherein the first direction is a direction toward an inner periphery of the drive ring, and the second direction is a direction toward an outer periphery of the drive ring. Barrier mechanism. The lens barrier mechanism of a camera according to claim 1, wherein the cam member has a hook portion on both ends for engaging with the torsion spring. 2. The lens barrier mechanism according to claim 1, wherein the support shaft is a protrusion formed on a decorative plate.

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