JPH03185669A - Disk clamp device - Google Patents

Abstract

PURPOSE:To prevent the malfunction of a clamp by providing a cover which blocks a permanent magnet for a device which presses a disk to a turntable by using the magnetic attraction effect by the permanent magnet. CONSTITUTION:A cylindrical permanent magnet 12 is fitted to the inside part of bowl-shaped clamper 11, and a cover 13 is abutted and fixed on the lower surface of this permanent magnet 12. The cover 13 is made of a metallic disk, may be either a non-magnetic body or a magnetic body, and its outside diameter is made to be 2-3mm larger than the outside diameter of the permanent magnet 12. The end tip of a clamp pin 14 is made to be semispherical, a flange 14a is provided near that, and the cover 13 is locked by this flange 14a. A taper-like step 11a is provided at the lower surface of the clamper 11, and the cover 13 is arranged inside of this step 11a. Thus, the malfunction of the clamp can be prevented even when the permanent magnet is chipped and a magnetic piece is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a disk clamping device that clamps a disk to a turntable using the magnetic adsorption effect of a permanent magnet.

[Prior Art] FIG. 4 shows a cross-sectional view of a conventional disk clamp device.
The clamping device places the disk D on a turntable 1, and from above the disk D is fixed to a spindle 4 rotated by a motor 3 by a clamper 2, and a Taber cone 5 is further attached to the spindle 4 so as to be slidable in the axial direction of the spindle 4. A compression spring 6 is interposed between the Taber cone 5 and the turntable 1. Further, an annular yoke 7 made of a ferromagnetic material is attached around the tip of the spindle 4, and a guide hole 8 is formed in the top of the spindle 4. A clamp pin 9 that fits into the guide hole 8 is projected from the center of the clamper 2, and a permanent magnet lO is arranged around the clamp pin 9 to apply a magnetic attraction force to the yoke 7.
is located.

To fix the disk D, the center hole Da of the disk D is fitted into the Taber cone 5, and the clamper 2 is placed over the disk D from above. At this time, the clamp pin 9 fits into the guide hole 8 of the spindle 4, and the permanent magnet lO and the yoke 7
are opposed to each other with a slight distance between them, and the clamper 2 is urged toward the turntable 1 by the magnetic attraction force, and the disc D is moved b-riei+L1/r11181wyuzu"!-
210-[Problem to be Solved by the Invention] However, in the conventional example described above, since the lower surface of the permanent magnet 10 is exposed, the fragments generated when a part of it is chipped expose the same permanent magnet 10. 0.2 between the yoke 7 and the permanent magnet 10 when it is attracted to the surface and clamps the disk D.
It may get caught in a gap of about 0.8 mm, causing a clamping failure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disk clamp device that prevents clamping failures caused by fragments of a permanent magnet being pinched between the permanent magnet and the yoke.

[Means for Solving the Problems] In order to achieve the above object, a disk clamp device according to the present invention presses a disk against a turntable using magnetic attraction by a permanent magnet. This is characterized by the provision of a cover that closes off the permanent magnet.

[Function] By providing the cover in the disk clamping device having the above configuration, even if the permanent magnet is chipped and fragments are generated, clamping failure due to the fragments can be prevented.

[Example] The present invention will be explained in detail based on the example illustrated in FIGS. 1 to 3. Note that the same reference numerals as in FIG. 4 indicate equivalent members.

FIG. 1 is an exploded perspective view of the clamper unit, and FIG. 2 is a sectional view of the device. A cylindrical permanent magnet 12 is fitted inside a roughly bowl-shaped clamper 11, and the lower surface of this permanent magnet 12 is A cover 13 is abutted, these are clamp bins 14,
It is fixed with washers 15 and screws 16. The cover 13 is made of, for example, a metal disc with a thickness of about 50 um, and may be made of either a non-magnetic material or a magnetic material, and has an outer diameter larger than the outer diameter of the permanent magnet 12 by about 2 to 3 mm. The tip of the clamp bottle 14 has a hemispherical shape, and a flange 14a is provided near the tip, and the cover 13 is secured by the flange 14a. A tapered step 11a is provided on the lower surface of the clamper 11, and the cover 13 is disposed within this step 11a.

FIG. 3 shows a cross-sectional view of the second embodiment, in which the cover 13 is in contact with the top of the step 11b provided on the clamper 11, and is fixed by directly adhering to the permanent magnet 12 instead of being locked by the flange 14a. has been done. Further, the clamp bottle 17 is pushed in from above the permanent magnet 12.

In the disk clamping device configured in this way, even if a part of the permanent magnet 12 breaks off, the fragment will not come out of the space closed by the cover 13, and this fragment will not become an obstacle to the clamp. do not have.

In the above embodiment, the permanent magnet 12 is placed on the clamper II side.
Although the case is shown in which the permanent magnet 12 is incorporated, it is also possible to attach the permanent magnet 12 to the turntable l side.

[Effects of the Invention] By providing a cover that closes off the permanent magnet, the clamping device can prevent clamping failure caused by even if the permanent magnet is chipped and fragments are generated.

[Brief explanation of drawings]

Drawings 1 to 3 show an embodiment of the disk clamping device according to the present invention, in which Fig. 1 is an exploded perspective view of the clamp unit, Fig. 2 is a cross-sectional view, and Fig. 3 is a view of the second embodiment. FIG. 4 is a cross-sectional view of a conventional example. 4 is a clamp bin, 7 is a yoke, 11 is a clamper,
12 is a permanent magnet, and 13 is a cover.

Claims (1)

[Claims] 1. A disk clamping device that presses a disk against a turntable by utilizing the magnetic adsorption effect of a permanent magnet, characterized in that the disk clamping device is provided with a cover that closes off the permanent magnet.