JPH0643876Y2 - Disk centering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a disc centering device used in a cutting device for an optical disc master or the like.

[Conventional technology and its problems]

It is desirable that the guide track of an optical disk, the servo track of a magnetic disk, and the like be concentric with the hole circle diameter in the case of a holed disk and the outer diameter in the case of a disk without holes. Therefore, when a signal is written in the track groove, it is necessary to set the disc so that the center of the inner diameter or the outer diameter of the disc and the center of rotation coincide.

In general, the disc has a precise roundness of the outer diameter or the inner diameter, but there is a large variation in the dimensions of the discs. Therefore, the method of hitting the outer circumference of the disc with a hammer etc. And it takes a long time to obtain accuracy.

Therefore, various devices for mechanically centering the disc have been proposed, and as a typical example thereof, a collet chuck is provided at the center of a turntable and the collet chuck grips the peripheral surface of the disc. There is an apparatus for centering the paper, and those proposed in Japanese Patent Application Laid-Open No. 61-152353 and Japanese Patent Application No. 63-37737.

However, in the centering device using the above collet,
The mechanism of the collet chuck and the device for expanding it becomes complicated, and when it is used for a disk without a hole that is centered on the outer diameter, the chuck diameter becomes large and the entire device becomes too large. There are some drawbacks.

On the other hand, the technique proposed in Japanese Patent Laid-Open No. 61-152353 presses the disk placed on the turntable with the work presser, detects the runout at that time with the runout detection body, and The movement of the work pusher is controlled so that the amplitude of the work is reduced. However, this structure requires a long time for the centering and has a drawback that the centering mechanism becomes complicated. Since the centering is performed while rotating the disk, there is a risk that the disk may fly out of the turntable when the device malfunctions.

Further, in the technique proposed in Japanese Patent Application No. 63-37737, as shown in FIG. 4, nozzles 31 and 32 for blowing and sucking air are provided on the turntable 30, and the nozzles 31 and 32 are used to eject the disc 33. Air is blown out to the inner and outer circumferences to perform centering, but in the case of thin discs, there may be problems with the disc rigidity for centering and it may not be possible to use it. There is a drawback that the centering accuracy is easily affected by scratches. Further, there is a defect that the surface of the disk is contaminated by dust or the like that is wound up by the air blown out from the nozzle.

[Purpose of device]

This invention has been made in view of the drawbacks of the above-described conventional centering device, and is an outer diameter-based centering system that can perform centering regardless of the presence or absence of a hole in the disk, and has an extremely simple structure. It is an object of the present invention to provide a centering device capable of accurately centering a disc in a small space.

[Means for achieving the purpose]

In order to achieve the above-mentioned object, the present invention provides a taper piston having a center axis of rotation of a table as an axis line, below a central portion of a turntable having a disk fitting hole on an upper surface thereof so as to be movable on the center axis of rotation. Inside the turntable, disc pressing arms that are swingable in the radial direction of the disc fitting hole are attached at at least three locations along the outer periphery of the disc fitting hole at equal intervals. Forms a hole through which the upper end of the pressing arm appears, and a push rod is interposed between the lower end of the pressing arm and the tapered surface of the tapered piston, and the swing fulcrum of the pressing arm is It is arranged closer to the upper end than the lower end.

As a second means for achieving the object, in the centering device having the above structure, an air suction nozzle port is provided on the bottom surface of the disc fitting hole.

[Action]

When the disc is fitted into the disc fitting hole and the taper piston is moved up and down, the push rod pushed by the tapered surface of the piston pushes the lower end of the disc pressing arm, and the pushing arm is directed toward the center of the disc fitting hole. To rock. By this swinging, the upper end of the pressing arm is projected into and retracted from the inside of the disc fitting hole to press the outer peripheral surface of the disc, thereby aligning the center of the disc with the center of the spindle.

Further, if an air suction nozzle opening is provided in the disc fitting hole, the lower surface of the disc fitted in the fitting hole can be sucked into the bottom of the fitting hole by sucking air through the nozzle opening. It is possible to prevent floating.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a turntable 3 is attached to an upper part of a spindle 1 via a thrust plate 2, and a disc fitting hole 4 is formed in an upper surface of the turntable 3. The inside of the disc fitting hole 4 is formed in such a size that the disc 5 is fitted with a slight clearance.
The centers of the disc fitting hole 4 and the turntable 3 coincide with the rotation center axis of the spindle 1.

Inside the turntable 3, the thrust plate 2, and the spindle 1, an air suction passage 6 is formed for inserting them, and the suction passage 6 has a plurality of upper ends branched and formed on the bottom surface of the disc fitting hole 4, respectively. The suction nozzle port 6a is formed by opening in the concentric groove 7.

Further, the turntable 3 has a cylindrical piston mounting hole 8 formed in the lower central portion thereof, and a taper piston 9 is slidably mounted inside the mounting hole 8 while keeping airtightness. The axis of the mounting hole 8 and the taper piston 9 coincide with the rotation center axis of the spindle 1, and the taper surface 9a is formed on the outer peripheral surface of the taper piston 9 and is symmetrical to the axis. Further, an air passage 10 is formed below the mounting hole 8, and an end (not shown) of the air passage 10 is connected to an air fan or the like. Through this air passage 10, the pressure of the compressed air is the bottom of the taper piston 9. It is supposed to

A coil spring 11 is attached to the upper portion of the piston 9, and the elasticity of the coil spring 11 always urges the piston 9 downward.

On the other hand, a space 12 for accommodating the disk pressing arm 13 is formed inside the turntable 3. The cavities 12 are arranged at three locations at equal intervals along the outer circumference of the disc fitting hole 4, and the upper portion of the cavities 12 is a long hole communicating with the outer circumference of the disc fitting hole 4. 17 are formed.

The disk pressing arm 13 has a spherical pressing terminal 14 at the upper end and a block 15 having a V-shaped groove 16 at the lower end, and both side surfaces of the block 15 are brought into sliding contact with both side surfaces of the space 12. The inside of the space 12 is guided so as to be movable in the radial direction of the fitting hole 4. The upper end of the pressing arm 13 is inserted through the elongated hole 17 and protrudes from the bottom surface of the disk fitting hole 4 to a height about the thickness of the disk 5, and the pressing terminal 14 is pressed in the protruding state. It is movable toward the center of the fitting hole 4 within the range where the arm 13 and the elongated hole 17 are fitted together.

In addition, a rod hole 18 that extends in a horizontal direction in a radial direction from the piston mounting hole 8 communicates with the lower end of the hollow space 12.
A push rod 19 is slidably inserted into 18 without a gap, and one end of the push rod 19 projects into the space 12 and abuts on the V-shaped groove 16 of the block 15. The other end of the push rod 19 projects into the mounting hole 8 and is in sliding contact with the tapered surface 9a of the tapered piston 9.

On the other hand, a coil spring 20 that presses the block 15 toward the push rod 19 is attached to the opposing surface of the V-shaped groove 16, and the elasticity of the coil spring 20 causes a space between the pressing arm 13 and the push rod 19 and a push. The rod 19 and the taper piston 9 are in close contact with each other, and play in the contact portion is removed.

The pressing arm 13 has a coil spring 21 provided between the end wall of the space 12 and the pressing arm 13 so that the vicinity of the pressing terminal 14 is a taper pin 22 mounted in the tangential direction of the disc fitting hole 4. It is pressed so that it always contacts the outer peripheral surface.

The taper pin 22 is attached to the outside of the disc fitting hole 4 in a hole 23 formed in the tangential direction of the fitting hole 4, and is fixed by a screw 24 screwed from the side. The hole 23 has an opening in the middle to the long hole 17, and the taper pin 22 is a hole.
A part of its outer circumference is exposed in the elongated hole 17 when attached to the hole 23.

The centering device according to the embodiment of the present invention is configured as described above, and its operation will be described below.

When pressure air is supplied from the air passage 10 to the bottom of the piston 9, the piston 9 rises, and at the same time, the push rod 19 pushed by the tapered surface 9a horizontally moves outward and pushes the lower end of the pressing arm 13 outward.

By pushing this push rod 19, the pushing arm 13 swings about the contact point with the taper pin 22 as a fulcrum, and the pushing terminal at the upper end is pushed.
14 moves toward the center of the fitting hole 4. Therefore, the disc 5 is pushed by the pressing terminals 14 from the three directions on the fitting surface, and is centered so that the center thereof coincides with the rotation center of the spindle 1. After that, the disc 5 is fitted into the disc fitting hole 4, then the air suction passage 6 is evacuated, the lower surface of the disc 5 is sucked by the nozzle opening 6a, and the disc 5 is attracted to the bottom surface of the fitting hole 4. .

In the above case, since the position of the swinging fulcrum of the pressing arm 13 is provided in the vicinity of the pressing terminal 14, which is the point of action, and the lever ratio is remarkably increased far from the force point position where the push rod 19 abuts, the taper piston 9 Even if the play between the turntable 3 and the turntable 3 or the play between the push rod 19 and the rod hole 18 or the wear of these parts is present in the contact portion, the play becomes significantly small at the position of the pressing terminal 14. There is an advantage that the deterioration of the centering accuracy can be made extremely small.

To remove the disk 5 centered as described above, the air passage 10 is evacuated to reduce the pressure inside the air passage 10. As a result, the taper piston 9 is lowered by the elasticity of the coil spring 11, and at the same time, the push rod 19 is moved inward by the pressing of the coil spring 20, and the pressing arm 13 is swung so that the pressing terminal 14 is directed outward. Therefore, the disc 5 can be taken out from the fitting hole 4 by being released from the pressing arm 13.

By the way, in the above structure, when the pressing arm 13 is newly incorporated in the turntable 3 or when the pressing arm 13 is replaced, the center of the disk fitting hole 4 of each pressing terminal 14 is naturally caused by an assembly error or a manufacturing error of the pressing arm. There is variation in the distance from. Therefore, an adjusting mechanism capable of independently adjusting the position of the pressing terminal 14 is required. In this embodiment, this can be done by adjusting the position of the taper pin 22. That is, the taper pin 22 and the hole 23
When it is moved inward, the amount of protrusion of the taper pin 22 into the inside of the elongated hole 17 changes, so that the position of the terminal 14 of the pressing arm 13 can be moved toward and away from the center of the fitting hole 4. This position adjustment is performed for each pressing arm 13 to set the position of each pressing terminal 14 at an equal distance from the center of the fitting hole 4.

[Effect of device]

This invention has the following effects by being configured as described above.

(1) Since the taper piston and the pressing arm are connected by the push rod, the size of the entire device can be reduced, and the device can be incorporated in the turntable as in the embodiment. When the device is incorporated in the turntable, the setup change when the size of the disk changes can be achieved simply by exchanging the turntable, and the workability is good.

(2) Since the lever ratio of the pressing arm is increased, the effects of backlash and wear that occur between the tapered piston and the piston mounting hole or between the push rod and the rod hole are extremely small at the upper end of the pressing arm. Since the centering can be performed easily and a large centering force is generated at the upper end portion of the pressing arm, the centering is always stable because it is less affected by the weight and posture of the disc.

(3) Since the outer peripheral surface of the disk is held by the pressing arm to restrict the movement, the work does not jump out during rotation, and the work can be performed safely.

(4) Since there is no portion projecting above the disc, it is not necessary to consider interference during cutting work near the center of the disc, and workability is good.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment according to the present invention, FIG. 2 is a partially cutaway plan view of the same as above, FIG. 3 is a perspective view showing a main part of the same, and FIG. FIG. 1 ... Spindle, 3 ... Turntable, 4 ... Disc fitting hole, 5 ... Disc, 6 ... Air suction passage, 6a ... Suction nozzle port, 8 ... Piston mounting hole, 9 ... Tapered piston , 10 …… Air passage, 11 …… Coil spring, 13 …… Push arm, 14 …… Push terminal, 15 …… Block, 17 …… Long hole, 19 …… Push rod, 20, 21 …… Coil spring, 22… … Taper pin, 23 …… hole.

Claims (2)

[Scope of utility model registration request] 1. A taper piston having a rotation center axis of the table as an axis is movably provided below a central portion of a turntable having a disc fitting hole on an upper surface thereof, and inside the turntable, A disk pressing arm capable of swinging in the radial direction of the disk fitting hole is attached to at least three locations along the outer circumference of the disk fitting hole, and the upper end of the pressing arm is attached to the outer circumference of the disk fitting hole. A push rod is provided between the lower end of the pressing arm and the tapered surface of the taper piston, and the swing fulcrum of the pressing arm is closer to the upper end than the lower end. A disk centering device characterized by being arranged in a line. 2. The disk centering device according to claim 1, wherein an air suction nozzle port is provided on the bottom surface of the disk fitting hole.