Apparatus and method for verification of jacket for floppy disk

Apparatus and a method for verifying that the various dimensions and shape of the jacket for a floppy disk are correct and within predetermined tolerance ranges. The apparatus of the present invention includes instruments for determining the warpage of the jacket, the parallelism between a pair of primary fold lines of the jacket, the squareness between the first fold line of the jacket and each of the primary fold lines of the jacket, the distance from the central line of the jacket to each of the primary fold lines thereof, the width and depth of a write-enable slot and the distance of the slot to the first fold line of the jacket, the squareness of all four sides of the jacket with reference to each other, and the thickness of the regions of the primary and final fold lines. The method of the present invention comprises a series of steps including the steps of determining the warpage of the jacket, parallelism between the first fold line and each of the primary fold lines, the squareness of each primary fold line with reference to the first fold line, the distance between the central line of the jacket and each of the primary fold lines, the width and depth of the write-enable slot and its distance to the first fold line, the squareness of all four sides relative to each other, and the thickness of the regions of the primary and final fold line areas. Warpage is determined by dropping the jacket through a generally vertical slot, and the other determined with dial gauges or other similar devices.

This invention relates to improvements in the calibration of equipment for 
making jackets for floppy disks and, more particularly, to apparatus and a 
method for determining the dimensional characteristics of such a jacket. 
BACKGROUND OF THE INVENTION 
In the making of jackets for floppy disks, it is important that the jackets 
have the proper dimensions and shape to fit properly in disk drives of 
conventional construction. Such disk drives will not accept a floppy disk 
if the jacket of the floppy disk is not within predetermined tolerance 
ranges as to warpage, thickness, squareness, and parallelism with 
reference to the edges of the jacket. Thus, it is mandatory that the 
jackets be of the proper size and shape and to be able to conform to a 
desired configuration within tight tolerances. To assure that jackets meet 
these requirements, a need has existed for an improved apparatus and a 
method for determining the dimensional characteristic of the jackets of 
floppy disks so that such jackets can be readily used with conventional 
disk drives. The present invention satisfies this need as hereinafter 
described. 
SUMMARY OF THE INVENTION 
The present invention provides a group of instruments which are adapted to 
be placed adjacent to each other to quickly determine certain dimensional 
features of the jacket of a floppy disk. Thus, knowledge of such features 
can be used to establish whether or not the jacket falls within tolerance 
ranges which are deemed acceptable in order for the jacket to be used with 
conventional disk drive equipment. Thus, the jacket, whose features are 
found to be acceptable, can be used for containing a floppy disk. 
Otherwise, the jacket must be discarded because it could later cause 
operational problems which could be damaging to the equipment with which 
the jacket is intended to be used. 
The apparatus of the present invention is adapted to measure a number of 
features, including the warpage of a jacket, the parallelism between a 
pair of primary fold lines at the sides of the jacket, the squareness 
between each primary fold line and the central or first fold line of the 
jacket, the distance from each primary fold line to the center line of the 
jacket, the width and depth of a write-enable slot at one side edge of the 
jacket and the distance from this write-enable slot to the central or 
first fold line of the jacket, the squareness of all four sides of the 
jacket relative to each other and the thickness of the jacket in the 
primary fold and final fold line areas thereof. All of the aforesaid 
dimensional features of the present invention can be quickly and easily 
determined with the use of a minimum amount of space and equipment, at 
minimum cost and with a high degree of accuracy and precision. 
The primary object of the present invention is to provide apparatus and a 
method for determining a number of dimensional characteristics of a jacket 
for a floppy disk wherein said characteristics can be used to determine 
the acceptability of the jacket for use in containing a floppy disk, 
whereby such determination can be used to verify jacket-making equipment 
with a high degree of accuracy and precision. 
Further objects of this invention will become apparent as the following 
specification progresses, reference being had to the accompanying drawings 
for an illustration of the invention.

The present invention is directed to a combination of instruments as shown 
in FIGS. 1 and 2-8 for verification of certain design dimensions of the 
jacket of a floppy disk after the jacket has been folded to present at 
least a pair of primary folds and later folded to present a final fold. 
The completed jacket to be measured or verified using the instruments of 
the present invention is broadly denoted by the numeral 10 and is shown in 
its completed form in FIG. 1A. 
Jacket 10 is formed from a single sheet or blank 12 (FIG. 8) comprised of a 
pair of panels 14 and 16 which are connected together along a first or 
central fold line 18, the material of the jacket being of flexible sheet 
material of conventional construction. Panels 14 and 16 have circular 
holes 20 and 22 and slots 24 and 26, respectively, which mate with each 
other and form a single hole and a single slot when the panels are folded 
along line 18 and are in face-to-face relationship to each other. Panel 14 
has a pair of side flaps 28 and 30 which are provided with angled end 
edges and which are adapted to be folded along primary fold lines 32 and 
34, respectively, after panel 16 has been folded into face-to-face 
relationship to panel 14. 
Jacket 10 is shown in FIG. 9 with flaps 28 and 30 in abutting, face-to-face 
relationship to the outer surface of panel 16, thereby effectively 
coupling panels 14 and 16 into face-to-face relationship with each other. 
The attachment of the flaps 28 and 30 to panel 16 is accomplished by heat 
welding, adhesive or other means. 
Panel 14 has a third flap 36 which is foldable along a final fold line 38 
so that flap 36 overlies the adjacent margin of panel 16. FIG. 9 shows the 
jacket before the final fold of flap 36 along final fold line 38; however, 
FIG. 1A shows jacket 10 after the final fold of flap 36. 
Panel 14 further has a rectangular notch 40 (FIG. 8) therein which 
straddles fold line 32, the notch being a write-enable slot 42 which is 
open at its outer end after flap 28 has been folded along primary fold 
line 32 as shown in FIG. 9. A crescent-shaped recess 44 is formed in the 
marginal edge 46 of panel 16 to accommodate slot 40 and slot 42. Without 
recess 44, the marginal edge of panel 16 would block notch 42. 
Timing holes 48 and 50 are provided in panels 14 and 16. These holes mate 
with each other to form a single hole 51 (FIG. 9) when the jacket is 
completely folded as shown in FIG. 1A. The single hole mates with timing 
holes in the inner peripheral margin of the floppy disk inserted in the 
jacket. 
A first instrument for measuring the thickness or warpage of jacket 10 is 
broadly denoted by the numeral 48 and includes a body 50 (FIG. 1) having a 
pair of slots 52 and 54 therethrough, the slots being of a size sufficient 
to accommodate the width of the jacket. The width of the slots is chosen 
to be no greater than a certain dimension. For instance, slot 52 can be 
made for a primary fold width of 0.085 inch, 0.090 inch or 0.095 inch. 
Slot 54 is used for the jacket after the final fold has been made and it 
typically has a width of 0.102 inch, for example. Slot 52 could have a 
range of widths, such as 0.085 to 0.095 inch while slot 54 could have a 
dimension range of 0.090 to 0.102 inch. Any warpage of a jacket placed in 
either slot will cause the jacket to hang up or jam in the slot and the 
jacket will not pass through the body 50. 
If the jacket passes through the selected slot, it will strike a plate 56 
which causes it to fall into a bin defined by a base plate 58 with sides 
60 and 62. Side walls 64 and 66 support body 50 on a base 68. 
FIG. 2 shows an instrument 70 having a main body 72 provided with a flat 
surface 73 for supporting a jacket 10 and reference edge 74 adjacent to 
surface 73, edge 74 adapted to be engaged by jacket 10 near one of the two 
primary fold lines 32 and 34 of the jacket. The instrument 70 measures 
jacket side fold width and parallelism of the side edges of the jacket 
because the body 72 has a dial gauge 76 mounted thereon, the dial gauge 
having a shiftable leg 78 whose outer end bears against the jacket at one 
primary fold line, such as fold line 32, when the other primary fold line, 
such as fold line 34, engages reference edge 74. The instrument 70 is used 
by moving the jacket 10 so that it moves from left to right or right to 
left with one of the primary fold lines in engagement with the reference 
edge 74 of body 72. Any defect in the dimension if the primary fold lines 
are not in substantial parallelism of the fold line will be detected by 
gauge 76. A typical tolerance is .+-.0.010 inch when either primary fold 
line engages reference edge 74. 
Another instrument of the present invention is broadly denoted by the 
numeral 80 (FIG. 3) and includes a body 82 having a first reference edge 
84 and a pair of side reference edges 86 and 88 generally perpendicular to 
reference edge 84. A dial gauge 90 is associated with edge 86 and a dial 
gauge 92 is associated with edge 88. A recess 94 extends into body 82 
below the level of the surface 96 on which jacket 10 is to be placed for 
measuring the squareness of the jacket. The recess 94 is to facilitate the 
manual pick-up of the jacket after the measurements have been made with 
gauges 90 and 92. 
The squareness of a jacket 10 is measured by instrument 80 between the 
first fold line 18 and each of the primary fold lines 32 and 34. When 
instrument 80 is used, the jacket 10 is placed on flat surface 96 with 
first fold line 18 in engagement with reference edge 84 and primary fold 
line 32 in engagement with edge 86. Any departure from the squareness 
between these two fold lines of the jacket will be detected by gauge 90. A 
typical tolerance is .+-.0.015 inch. Similarly, the squareness between 
fold line 18 and fold line 34 is detected when the jacket is shifted 
slightly to the right to move primary fold line 34 into engagement with 
reference edge 88, whereupon gauge 92 will determine any departure from 
squareness between fold lines 18 and 34. 
FIG. 4 shows an instrument 100 for measuring the distance from the center 
line of jacket 10 to each primary fold line 32 or 34. To this end, 
instrument 100 includes a body 102 having a flat surface 104 on which the 
jacket is mounted. A first reference edge 106 is adapted to be engaged by 
first or central fold line 18 while a second reference edge 108 is adapted 
to be engaged by a primary fold line 32 or 34. A gauge 110 has a leg 112 
engageable by the primary fold line of the jacket when the fold line is 
adjacent to and engages reference edge 108. A projection 114 is rigidly 
secured to surface 104 and is adapted to be received in slot 26 when the 
jacket is in place on surface 104. Thus, any departure from a safe 
tolerance in the distance between the primary fold line and a reference 
edge 114a on projection 114 will be detected by gauge 110. 
FIG. 4a shows an instrument 120 for measuring the distance between the 
central or first fold line 18 of the jacket and the adjacent extremity of 
the slot 26 when the jacket is in place on surface 123 of instrument 121. 
To this end, instrument 121 includes a body 125 of which flat surface 123 
forms a part. A first reference edge 127 is adapted to be engaged by a 
primary fold line 32 or 34 while a second reference edge 129 is adapted to 
be engaged by central fold line 18 of the jacket. A gauge 131 has a leg 
133 engageable by the central fold line 18 of the jacket when the fold 
line is adjacent and engages reference edge 129. A cylindrical projection 
135 rigidly secured to surface 123 is adapted to be received in slot 26 
when the jacket is in place on surface 123. Thus, any departure from a 
safe tolerance in the distance between central fold line 18 and the 
adjacent extremity of slot 26 will be detected by gauge 131. 
FIG. 5 shows an instrument 120 having a body 122 provided with a flat 
surface 124 for supporting jacket 10. Instrument 120 measures the minimum 
width, depth and location of the write-enable notch 42 (FIG. 9) relative 
to the first fold line 18 of the jacket. The body 122 has a pair of dial 
gauges 126 and 128, the gauges having legs 130 and 132, respectively. 
Gauge 126 is near a side reference edge 127 adapted to be engaged by 
primary fold line 32 of a jacket 10 on surface 124. Leg 130 has an outer 
end which is adapted to enter write-enable slot 42 to measure the minimum 
width and depth of the slot. Any departure from a safe tolerance, such as 
0.010 inch, will be detected by gauge 126. Any departure from a safe 
distance or location of the notch 42 relative to lower edge or fold line 
18 will be detected by gauge 128. 
Another instrument of the present invention is broadly denoted by the 
numeral 140 and is adapted for use in verifying the final fold line 36, 
and the overall size and squareness on all four sides of the jacket to 
insure optimum accuracy and efficiency. To this end, instrument 140 
includes a body 142 having a flat surface 144 for supporting jacket 10. A 
pair of reference edges 146 and 148 are provided for body 142, the edges 
being generally perpendicular to each other. Gauges 150 and 152 have legs 
154 and 156 for engaging a primary fold line while the legs 158 and 160 of 
gauges 162 and 164, respectively, are adapted to engage the final fold 
line 38 of the jacket. Thus, the squareness of the jacket can be 
determined for the one primary fold line, then the jacket can be inverted 
and the same test can be conducted for squareness for the other primary 
fold line. A typical tolerance is .+-.0.010 inch. 
FIG. 7 shows an instrument 170 for measuring the thickness of the jacket at 
the primary fold and the final fold areas of the jacket. To this end, 
instrument 170 includes a body 172 having a reference edge 174 against 
which a primary fold line 32 or 34 is placed. A gauge 176 having a leg 178 
engages the jacket at the fold line near the fold line of the jacket which 
engages edge 174. The thickness can then be determined as the jacket moves 
along the flat surface 180 of body 174 with the primary or final fold line 
in engagement with surface 174. 
The instruments of the present invention are human engineered for simple, 
fast and accurate verification of fabrication machinery for making jacket 
10. The simplicity of the instruments of the present invention allows a 
maintenance technician to identify and locate a problem in the production 
of jackets rapidly. Secondly, because of the fast and accurate sampling, 
optimum productivity is achieved. The instruments can all be located 
adjacent to each other at a measurement station so that a jacket can be 
quickly and easily measured by a person without requiring the person to 
move from one station to another. 
While mechanical dial gauges have been used to provide the measurements, 
other types of measuring devices can be used which are electronic, of 
photo-optical construction, of laser construction and the like. 
In carrying out the method of the present invention, a completed jacket 10 
is used with instrument 48 to measure the warpage of the jacket. The slot 
52 or 54 is first selected, then the jacket is dropped into the selected 
slot. For instance, slot 52 could have a width range such as 0.085 to 
0.095 inch, while slot 54 could have a dimension range of 0.090 to 0.102 
inch. If the jacket jams or hangs up on the slot, then the jacket is 
sufficiently warped to be unuseable, and the jacket is discarded. If the 
jacket passes through the slot, the jacket will fall into bin 58 and be 
removed in due course from the bin. 
Another step of the method of the present invention includes placing the 
jacket on instrument 70 (FIG. 2) and moving the jacket in a manner such 
that one of its two primary fold lines 32 and 34 engages reference edge 74 
as the other primary fold line move past and engages the outer end of the 
shiftable leg of dial gauge 76 of instrument 70. This step measures the 
parallelism between the primary fold lines. If any defect in this 
parallelism is detected by the dial gauge, the jacket is discarded. 
Another step in the method of the present invention is to determine the 
squareness of a jacket 10. The squareness is measured between the first 
fold line 18 and each of the primary fold lines 32 and 34. With first fold 
line 18 in engagement with reference edge 84 of instrument 80, one of the 
two primary folded lines 32 and 34 is in engagement with edge 86 
perpendicular to edge 84 of instrument 80. After the reading from dial 
gauge 90 is taken, the jacket is inverted, and the other primary fold line 
is brought into engagement with reference edge 86 as first fold line 18 
remains in engagement with edge 84. Any departure from a specified 
tolerance in the squareness of the jacket will be the basis for discarding 
the jacket. 
Another step in the method of the present invention is to determine the 
distance between each primary fold line at the center line of the jacket. 
To this end, fold line 18 is placed in engagement with reference edge 106, 
while a primary fold line is placed in engagement with edge 108. With one 
side edge of central slot 26 of the jacket engaging reference edge 114A 
(FIG. 4) of projection 114 extending into jacket slot 26, the reading of 
dial gauge 110 is taken. If the tolerance measured by the reading is less 
than a certain value, the jacket is acceptable; otherwise, the jacket must 
be discarded. After the first reading is taken with one primary fold line 
engaging edge 108, the jacket is inverted, and the other primary fold line 
is brought into engagement with edge 108, following which a reading is 
taken to determine if the jacket falls within the predetermine tolerance 
value. 
Another step of the method of the present invention is to measure the 
minimum width, depth and location of the notch 42 of the jacket 10 
relative to the first fold line 18 of the jacket. To this end, fold line 
18 is brought into engagement with the outer end of leg 132 of dial gauge 
128 of instrument 120 (FIG. 5). Then, the fold line 32 is brought into 
engagement with reference edge 127 with the outer end of leg 130 of dial 
gauge 126 in notch 42. If readings of gauges 126 and 128 fall within 
acceptable tolerance ranges, then the jacket is acceptable; otherwise, the 
jacket is discarded. 
Another step in the method of the present invention is to verify the final 
fold line 36 and the overall size and squareness of all four sides of the 
jacket. This is achieved by placing the jacket such that one of the 
primary fold lines engages edge 148 of instrument 140 (FIG. 6) while first 
fold line 18 engages reference edge 146, and as the outer ends of legs 158 
and 160 of dial gauges 162 and 164 engage the final fold line 38. When 
dial readings have been taken with one of the primary fold lines engaging 
reference edge 148, the jacket is inverted and the other primary fold line 
is moved into engagement with reference edge 148. If the dial readings for 
both gauges are within specified tolerance ranges, the jacket is 
acceptable; otherwise, the jacket must be discarded. 
Another step in the method of the present invention is to measure the 
thickness of the jacket at the regions of the primary fold lines 32 and 34 
and the region of the final fold line 38 of the jacket. To this end, the 
three fold lines are successively brought into engagement with reference 
edge 174 of instrument 170, and readings from dial gauges 176 are 
successively taken. If the readings are within specified tolerance ranges, 
the jacket is acceptable; otherwise, the jacket must be discarded. 
The various steps of the method of the present invention can be performed 
in substantially any order. The order mentioned above is not limiting, and 
the steps could be performed in an order different from that described 
above.