Write protection for memory diskettes

A slide component is configured to be inserted into a recess in an assembled magnetic diskette cartridge and rotated about an edge of the slide component into operable orientation to be slideably positioned between locations in the recess that designate whether or not the magnetic disk in the cartridge is write-protected.

RELATED PATENT 
The subject matter of this application relates to the subject matter of 
U.S. Pat. No. 5,210,671, which is incorporated herein by this reference. 
FIELD OF THE INVENTION 
This invention relates to 3.5" magnetic diskettes, and, more particularly, 
to a snap-in module for selectively providing write protection following 
manual or automated insertion and manipulation into position on the 
diskette. 
BACKGROUND OF THE INVENTION 
Many designs of 3.5" diskette packages contain a magnetic disk which is 
disposed to rotate while portions of the disk surfaces are in contact with 
magnetic transducers. Such magnetic diskette may be used once for 
recording information permanently and thereafter may be altered slightly 
via a write-protect tab to inhibit recording on the diskette thereafter. 
Such write-protect tab (or similar device) is usually located near a 
peripheral edge of the diskette package to be sensed by a transducer which 
determines whether a tab (or similar device) is in a particular location 
or not on the diskette package as the indication of whether or not the 
magnetic diskette is to be protected against further recording thereon. In 
some diskette designs, a tab may be omitted from a peripheral recess to 
indicate the write-protect condition in normal use, and in other diskette 
designs a slide device is included within a peripheral recess to indicate 
the write-protect condition in one slide position and an unprotected 
condition in another slide position. This latter diskette design greatly 
facilitates the alterable protection condition and the reusability of 
diskettes previously write-protected. A slide component for indicating a 
write protect or write unprotect condition is introduced into a peripheral 
recess of the diskette where such slide components is retained captive 
within slide tracks, or the like. Some end uses of the diskettes, such as 
duplicators, do not require the use of an alterable protection condition. 
However, for such end uses, it may be cost efficient to produce a diskette 
that is identical to the diskettes having the alterable protection 
condition except that a slide component is not introduced into the recess. 
After such diskettes are assembled, it may become desirable to add a slide 
component to the diskette. Present methods of inserting the slide 
component into the diskette require the housing package of the diskette to 
be pried apart, the slide component inserted into the recess, and the 
housing package resealed. This contributes to reject rate in automatic 
assembly procedures. 
SUMMARY OF THE INVENTION 
Accordingly, the preferred embodiment of the present invention includes a 
slideable component that is operable to indicate the write-protection 
condition of the diskette and that is insertable into a peripheral recess 
in the diskette package after the housing components which form the 
diskette package are firmly sealed together. In one embodiment, the slide 
component has a substantially rectangular body with two legs mounted 
thereto on opposite ends of a common edge of the body. The legs are of 
different lengths and a side of the body adjacent the shorter leg is 
chamfered to facilitate inserting the slide component into the peripheral 
recess for positioning the assembled diskette package without permanent 
deformation of the slide component or package. Once snapped into place, 
the slide component remains captivated therein but slideable between two 
locations in the recess.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, there is shown a bottom view of a diskette housing 9 
that includes length and width and thickness dimensions which are in 
accordance with standards requirements for 3.5" floppy magnetic diskette 
packages (or cartridges). Referring to FIG. 2, there is shown an expanded 
view of a peripheral recess 17 in the diskette housing 9. Referring to 
FIG. 3, there is shown a sectional view of the peripheral recess 17. The 
diskette cartridge 9 commonly has upper and lower faces 11, 13 of 
half-side housing components that are joined along seam 15 to enclose a 
magnetic disk disposed to be rotated by a spindle of a disk drive 
mechanism (not shown for clarity) that is oriented to couple to drive hub 
7 for rotation about an axis that is perpendicular to the plane of the 
drawing. The upper and lower faces 11, 13 may be formed of, for example, 
Acrylonitrile-Butadiene-Styrene (ABS) or High-Impact Polystyrene (HIPS). 
Such conventional magnetic diskette cartridges commonly include a slider 
or shutter 5 over an access port 6 for a magnetic transducer to interact 
with a surface or surfaces of the magnetic diskette within the housing 11, 
13, and also include a write-protect indicator (or slide component) 8 
within a recess 17 in the rear peripheral edge of the diskette cartridge 
near a corner thereof for positioning therein the tab or slide component 8 
that indicates the write-protect condition of the diskette. The recess 17 
and the slide component 8 therein is aligned with a transducer or switch 
in conventional diskette-utilizing equipment to detect the absence or 
presence of the slide component 8 at a selected location as an indication 
of the write-protected or write-unprotected condition of the disk within 
the diskette cartridge. The recess 17 has an aperture 21 of selected 
length 22 that is less than the internal length 25 of the write protect 
cavity and of selected width 29 that is less than the internal width 27 of 
the write protect cavity. As illustrated in the sectional view of FIG. 3, 
the recess 17 is relieved internally to a larger length 25 and width 27 
below the peripheral edge (and, to a depth through the housing) in order 
to provide a captivating surface flange 48 around the aperture 21. 
Recessed slide tracks beneath the surface flange 48 around the aperture 21 
may provide the captivating guides for a slide component 8 within the 
recess 17. As illustrated in the expanded view of FIG. 2, the recess 17 
has two bumps 28, 30 on each length 25 positioned for engaging the slide 
component 8, as described later herein, to lock the slide component 8 and 
to provide the write-protected or write-unprotected conditions, 
respectively. 
Referring now to FIGS. 4, 5, 6, and 7, there are shown top (or plan) view, 
bottom view, edge view, and sectional view, respectively, of the slide 
component 8 including a body 31 having legs 32, 33 spaced apart, 
substantially parallel to each other, and each attached on one end to 
opposite ends of a common edge 34 of the body 31. The sum of the length 
dimensions of both the leg 32 and an edge 37 of the body 31 adjacent the 
leg 32 is larger than the length dimension 22 of the aperture 21. The sum 
of the length dimensions of both the leg 33 and an edge 38 of the body 31 
adjacent the leg 33 is smaller than the length dimension 22 of the 
aperture 21. The leg 32 has a foot 35 on an end of the leg opposite the 
end of the leg attached to the body 31 extending outwardly from the body 
31 and substantially orthogonal to the leg 32. Similarly, the leg 33 has a 
foot 36 on an end of the leg 33 opposite the end of the leg 33 attached to 
the body 31 extending outwardly from the body 31 and substantially 
orthogonal to the leg 33. The feet 35, 36 are positioned for engaging the 
bumps 28, 30 of the recess 17, as described later herein. The edge 38 of 
the body 31 is chamfered at an angle greater than 90.degree. relative to 
the bottom of the body 31 to facilitate inserting the slide component 8 
into the recess 17 of the assembled diskette housing 9 without permanent 
deformation of the legs 32, 33, the body 31, or the housing 9. The body 31 
of the slide component 8 is substantially rectangular with a width 
slightly wider than the width of the aperture 21 and with a height 41 
above the corner tabs 39 that may protrude through the aperture 21 to the 
surface of the bottom face of the diskette cartridge. This slide component 
8 thus formed of a relatively flexible, resilient material, such as 
polyoxymethylene (POM), may thus be inserted along the edge 37 into the 
recess formed in the diskette housing, through the surface aperture 21 
after the housing is sealed along seam 15, and then rotated into position 
by camming the chamfered edge 38 of the body 31 along the surface flange 
48 to serve as a captivated slide component within the recess that can be 
positioned between ends of the aperture to identify the write-protected or 
write-unprotected conditions of the magnetic disk within the cartridge. 
In accordance with the preferred embodiment of the present invention, the 
slide component 8 has a selected width dimension 44 that is greater than 
the width dimension 29 of the aperture 21 but less than the width 27 of 
the recess 17. In an initial orientation, as shown in FIG. 8, the leg 32 
is inserted into the recess 17 through the aperture 21 so that the leg 32 
and the edge 37 of the body 31 engage one side of the recess 17 as shown 
in FIG. 9. Thereafter, the slide component 8 is rotated within the recess 
17 with the chamfered edge 38 camming along the captivating flange 48 of 
the aperture 21 so that the bottom of the slide component 8 engages the 
bottom surface of the recess 17, as illustrated in FIG. 10. In this 
orientation, the width dimension of the slide component 8 fits within the 
internal width 27 of the recess 17, and under the captivating flange 48 
around the aperture 21. Of course, slide tracks may also be disposed 
within the internal walls of the recess 17 to retain the slide component 8 
captive therein and to guide the slide component 8 between positions. The 
width dimension of the slide component 8 is sufficiently smaller than the 
length of the recess 17 to facilitate slideable movement within the recess 
17 along the axis of the length dimension thereof. The slide component 8 
is formed of relatively flexible, resilient material, as previously 
described, to accommodate the compression and distortion encountered when 
rotating the slide component 8 into position, as shown in FIGS. 9 and 10. 
In a write-protected condition, the foot 35 of the leg 32 engages the 
camming surface 28 for securing the slide component 8 in a first position. 
In a write-unprotected condition, the foot 35 of the leg 32 engages the 
camming surface 30 and the foot 36 of the leg 33 engages the camming 
surface 28 on the opposite side of the recess 17 for securing the slide 
component 8 in a second position. Movement of the slide component 8 within 
the recess 17 causes the feet 35, 36 to move along the camming surfaces 
28, 30 to thereby deflect the respective legs 32, 33, which in turn apply 
a spring force against the wall of the recess. Such a spring force secures 
the slide component in the first and second positions. The legs 32, 33 are 
asymmetrical in length to facilitate the insertion of the slide component 
8 into the recess 17. The shorter leg 33 allows the slide component 8 to 
move into a middle position in the recess 17 before snapping it therein. 
In the middle position, the level of strain on the slide component 8 
during the insertion is reduced. At least one leg may be attached to the 
body 31 at an angle extending outwardly from parallel to provide a greater 
spring force to thereby increase the frictional force of the foot against 
the wall of the recess 17. 
Therefore, the present invention provides a diskette cartridge having a 
slide component for indicating a write-protected condition or not. The 
longer leg and one edge of the slide component is first inserted into the 
recess and rotated into place by camming a chamfered edge and the shorter 
leg of the slide component relative to the surface flange of the recess.