JPH0626067B2 - Device and method for tightening disk - Google Patents

Description

Detailed Description of the Invention A. FIELD OF THE INVENTION The present invention relates to disc files, and more specifically, clamping a stack of discs to a hub and shaft with spacers therebetween to substantially eliminate radial loads. And method for forming a disc file.

B. All prior art disk drives include disk clamps to apply a compressive load to the disk stack to hold the disks in place. These clamps have a variety of configurations. Generally, these clamps are disk or bell shaped parts that act as springs and are compressed with screws or bolts.

As magnetic disks become smaller in diameter and track density increases, it becomes important to keep the disks parallel for proper conversion between the read / write head and the disk recording surface. The clamp is a disc
Radial loading of the stack can cause distortion and self-weight bending of the disc. This may result in head misalignment, resulting in errors due to skew, absent bits, bit shifting or signal distortion.

To avoid such distortions, the disk file should be assembled using clamps that apply pure compression loading. The clamp should also have a low spring constant to minimize load variations on the stack due to stack tolerances and changes in stack size in response to temperature changes.

U.S. Pat. Nos. 3,587,073, 4,065,799, and 4,672,488 describe various disk discs.
A clamp configuration is disclosed. IBM Technical Disclosure Bulletin, March 1987, p. Four
346, November 1977, p. 2376, and the March 1984 issue of the same magazine, p. 5444 discloses yet another configuration. These are the most appropriate prior art known to the Applicants. However, none disclose or propose a clamp having the improved construction disclosed and claimed herein.

C. SUMMARY OF THE INVENTION There is a need for a disk file clamp that provides a low spring constant and that is configured to substantially eliminate radial strain and load on the disk pack.

D. To this end, in accordance with the invention, an annular member having a plurality of regularly spaced radial slots for defining a plurality of identical tapered leaf springs. A clamp is provided that includes Each leaf spring terminates at the wide end of a common solid ring rim. This rim overhangs the spacers on the top disc in the stack.
Touching the ring. When the clamps are not pressed, contact is made with the spacer ring along the same horizontal plane as the centroid of the vertical section of the rim, or an annular line very close thereto. When an axial bias is applied simultaneously to the small innermost ends of all leaf springs, the rim has a rim of said annular line such that the radial load transmitted to the stack is substantially removed. Tighten the stack to the hub by pivoting inward and twisting in place. The nut acts to press the innermost end of the leaf spring to keep the spring pressed and to secure the stack and hub to the drive shaft.

E. EXAMPLE As shown in FIG. 1, a rigid disk file embodying the invention includes a stack of disks 10 separated by intervening spacers 11. The stack has, at its lower end, a flange 12 forming a part of the hub 13.
Supported by. Hub 13 surrounds shaft 14 and is press fit therein and driven thereby.
The clamp 20 serves to clamp the top disc to the hub 13 via the top spacer ring 21 and the top disc of the stack.

According to the present invention, as shown in FIG.
Includes a single annular member 22 having a plurality of regularly spaced radial slots 23 so as to form a plurality of identical tapered leaf springs 24. Each leaf spring is cantilevered inwardly from a common ring-shaped rim 25. The spring strips of each spring 24 are configured to provide a substantially uniform pressure distribution in the lateral and longitudinal directions. This configuration, which includes a tapered leaf spring, provides maximum vertical deflection for preselected load and allowable stress levels, and thus minimum spring constant. Each leaf spring 24 preferably has a boss 26 adjacent its inner narrow end.

According to an important feature of the invention, the rim 25 overhangs the spacer ring 21 when the clamp is assembled, as shown in FIG. The ring 21 is a flat horizontal surface 28 of the rim that abuts the flat horizontal top of the spacer ring 21.
The clamp 20 is supported at a series of points forming an annular line 27 around the inner end of the clamp. The face 28, and thus the line 27, lies in the same horizontal plane 28a as the center of gravity 29 of the cross section of the ring 25. The line 27 is very close to the center of gravity because the ring 25 overhangs.

In operation, as best shown in FIG. 4, moments are transmitted to the rim 25 as they are applied to the leaf spring 24 by the boss 26 via the clamp load washer 30 of about 2270 kg (about 5,000 lbs). This moment causes the rim 25 to pivot or twist inward at and along line 27. When the rim 25 pivots, the minimum moving point in the radial direction is the horizontal plane 2.
It is a point close to 8a.

By overhanging the rim 25 over the spacer ring 21 and placing the centroid 29 near the line of contact 27, the radial deflection of the clamp 20 at this line is substantially eliminated. Therefore, the radial load transmitted to the uppermost disk 15 via the spacer ring is also substantially eliminated. As a result, the top disc is clamped by the pressure between the hub flange 12 and the spacer ring 21, so that the top disc 15 and the stack are substantially free of self-weight bending.

The lower surface 31 near the inner end of the leaf spring 24 is in contact with the shoulder 32 of the shaft 14. Therefore, when a compressive load is applied through the washer 30, the tightening nut 33 is screwed into contact with the washer, holding the clamp 20 and holding it, so that the tightened disk stack can be moved to the hub 13 and the shaft 14. Fix it.

Note that, as shown, a surface 31 located near the inner end of each leaf spring 24 is provided on the depending portion 31a of each spring strip. The fact that the inclination angles of the surfaces 24a and 24b are different was for uniformly distributing the pressure in the lateral direction and the longitudinal direction of the leaf of each leaf spring 24. If preferred, the axial surface 32 can be higher than the upper surface of the hub,
The hanging portion 31a can be removed. However, regardless of the particular configuration chosen, it is essential that the stress be uniform over the entire length of each spring strip of leaf spring 24.

F. Effect of the Invention Disc stack. It can now be seen that the clamp has a low spring constant and removes the self-weighted bending of the disks of the stack as desired by substantially removing the radial load.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a disk file embodying the present invention. FIG. 2 is an enlarged perspective view of a disc clamp embodying the present invention. 3 and 4 are longitudinal sectional views of the clamp portion of FIG. 2 in a non-pressed state and a pressed state, respectively. 10 ... Disc, 11 ... Spacer, 12 ... Flange, 13 ... Hub, 14 ... Shaft, 20 ... Clamp, 2
1 ... Spacer ring, 22 ... Annular member, 24 ...
Leaf spring, 25 ... ring rim, 26 ... boss, 27 ... annular wire, 28a ... horizontal plane, 29 ... center of gravity, 30 ... washer, 31a ... hanging part, 32 ... shoulder, shaft surface, 33 ... Tightening nut.

Claims (3)

[Claims] 1. A plurality of substantially identical fasteners in a tightening device which serve to tighten a stack of parallel spaced disks to a hub having a portion supporting the lower end of the stack via a spacer ring. An annular member having a plurality of slots extending in the radial direction at even intervals so as to define a leaf spring that expands in a taper shape, and each leaf spring is common to each leaf spring at its diverging end. Coupled to a solid ring-shaped rim, the rim overhangs the spacer ring and is in substantially the same horizontal plane as the centroid of the vertical section of the rim when the tightening means is not pressed. A tightening device comprising contacting the rim with the spacer ring along an annular line proximate the rim. 2. A plurality of discs stacked in a stack, a plurality of spacers separating the discs, and a plurality of substantially equally spaced radii to define a plurality of substantially identical tapered leaf springs. An annular member having a plurality of slots extending in a direction, each leaf spring being joined at its flared end to a solid ring-shaped rim common to each leaf spring, said rim being said spacer ring. Of the spacer ring along an annular line proximate to the rim in a horizontal plane approximately the centroid of the vertical cross section of the rim when the clamping means is not pressed. A magnetic disk file comprising: tightening means comprising contact of the rims; and a hub including a portion supporting a lower end of the stack. 3. A plurality of radially spaced slots extending at even intervals to define a plurality of substantially identical tapered leaf springs, the wide ends of each leaf spring being common. An annular member terminating in a solid ring rim is used to enclose the spacer on the top disc of the stack, with a rim that overhangs in contact with it, and when the clamp is not pressed the rim Arranging an annular member along said line at an annular line near the rim in a horizontal plane substantially passing through the centroid of the vertical section; and said rim of said annular line. But applying a pressing force simultaneously to the small ends of all leaf springs so that they pivot and twist to substantially eliminate any radial load transfer to the stack. To How to tighten the stack of fixed disk that was in the hub.