Note: Descriptions are shown in the official language in which they were submitted.
~3~
BACKGROUND OF THE INVENTION
The present invention relates in general to control systems
for activating machines and in par-ticular to a ticket acceptor
and validation apparatus for use with a card~ tape or the like
encoded with magnetic signals.
Most vending machine~, laundry and dry cleaning machines and
the like which are provided for public use are coin-operated. ~ -
Many o~ these machines are made available twenty-four hours a day
and consequently are unattended or are supervised only at great
cost. Because of the presence of coins in these machines, the
machines have been and are, with increasing ~requency in recent
years, subject to a great deal o~ vandalism. The economic losses
which have resulted have not been limited to a loss o~ the coins,
but have included additional expenses necessitated by rep~irs to
the damaged control units and coin boxes and the losses associat-
ed with machines being inoperable for long periods of time while ;~
the repairs ~re being made.
There is also associated with a great many coin-operated
: ':
meohanism3 the problem of a lack of adjustability to accept ooins ;~
o~ di~erent denominations.~ Typically, whenever a change is made
in the number or type of coins required to operate such mechan- -`
isms, the entire mechanism must be replaced. There are mechan~
sm which accept various combinations of coins and provide
change; however, they are generally quite expensive and are typ-
ically limited to accepting nickels, dimes and quarters.
In certain ~oreign countries9 paper currency is widely used
in denominations corresponding closely to the cost of obtaining `
goods and services from a machine. Like the more expensive coin- -
operated mechanisms, a mechanism operable with paper currency is ; ,~
undesirably expensive. ;
Hereto~ore, a number o~ proposals have been made ror using a ;~
ticket or a card in lieu of coins ~or activating machines. In
one such proposal, a ticket of thermoplastic material is employed
2 ~ ~7~
,^ . .... .. : : , . :; .... .. ...
~)3~
as a substrate. On the substrate, th0re is provided a printed
circuit. An apparatu3 detects the presence of the printed cir-
cuit and, if the ticket is valid, activates a machine and
destroys the ticket. Thi~ is an excellent 901ution to the prob-
lem Or vandalism o~ machines and machin~ coin boxas, but, un
fortunately, each use requires a separate ticket and such tickets
tend to be easily duplicated.
Card3 bearing magnetic signals, on the othsr hand, may be
used repeatedly ror activating a machine by means Or an apparatus
which records on the card appropriate signals each time the card
is used and returning the card to the user. The number of times -~
the card may be used i8 readily controllable.
Presently, such cards are used repeatedly in locking mechan-
isms ror gaining aacess to secured areas. Cards Or this type
are also used ror gaining access through turnstiles, as in a
subway system. Typicall~, in the latter case, computers are
employed to read an amount encoded on the card~ The amount is
redueed aecording to predetermined oriteria and a lesser amount
recorded on the card in place of the previously encoded amount.
While appropriate for large installations, and providing relative
security against fraudulent duplication Or cardsJ the cost and ` -~
eomplexity of sueh computer-augmented control systems mltigate
their use in apparatus ror controlling the activation Or indi-~
vidual vending machines, laundr~ and dry cleaning maohines and
the like. Consequently, it is desirable to not only have a
relatively inexpensive means ~or using magnetic oards for oper-
ating machines but to have a means by which such cards can be
used with a reasonable degree Or security against fraudulentl~ -~
produced cards.
SUMMARY OF THE INVENTION
In view o~ the foregoing, a principal object o~ the inven~ ;
tion is a relatively inexpensive but reliable and secure control ~-
apparatus ror activating a machine using a magnetic card, tape or
~L~J~"3~ :
the like bearing magnetic signals.
Another object of the invention is an apparatus o~ the type
described above including means for modifying the signals on the
card so that the same card may be used repsatedly for activating
a machine.
A ~urther object o~ the invention is a conbrol apparatus of
the type described above which uses a card bearing magnetic sig- `
nals ror activating vending machines, laundry and dry cleaning
machines and the like which is relatively difficult to fraudu-
lently duplicate.
A principal feature of the present invention is the use of
a oard bearing pulse-width-modulated magnetic signals The coded
signal on the card corresponds to the number of times the card is
intended to be used for activ~ting a machine. Each time a machine
is activated, the coded number on the card is reduced by one. ~` -
Along with the data or "credit" signals, as these last described
signals are conveniently called, there are provided additional
signals called identification signals. The identi~ication sig-
nals are employed to validate the card. Means are also provided
to visually display a number which shows the remaining number of
. ~ .
times the card may be used each time the card is inserted in the -
~apparatus,
In addition to being pulse-width-modulated, the magnetic
signals ma~ also be saw~tooth-modulated. Saw-tooth-modulated ;
signals provide a deg~ee of seourity against a fraudulent dupli- -
cation in that they tend to be more dif~icult to analyze and
duplicate u~ing known techniques.
DESCRIPTION OF THE DRA:WINGS
The above and other objects, ~eatures and advantages of the
present invention will become apparent fro~ the following de-
tailed description in which
Fig. 1 is a top plan view o~ a typical card usad in accord-
ance with the present invention,
: . . .
~l~3~75~
Fig. 2 is an exploded perspectiv~ view ~howing a portion of
the reader uaed to read the card.
Fig. 3 ia a perspective view ~howing the reader assembled and
a card about to be inserted.
Fig. 4 is a vertical sectional view, somewhat schematic,
through the reader taken substantially along the line l~--4 of
Fig. 3. ~;
Fig. 5 is a horizontal sectional view taken substantially
along the line 5--5 of Fig. 4.
Fig. 6 is a vertical sectional view taken substantially
along the line 6--6 of Fig. 5.
Fig9 7 and 8 are fragmentary sectional views taken substan-
tially along the lines 7--7 and a--8 respectivel~ of Fig. 5.
Fig. 9 is a perspective view Or an encoder used in accord-
ance with the invention.
Fig. 10 is a horizontal sectional view taken substantially
along the line 10--10 of ~ig. 9.
Fig. 11 is a vertical sectional view taken substantially
along the line 11--11 of Fig. 10.
Fig. 12 is a block diagram o~ the apparatus o~ Fig. 2.
Figs. 13a-~ are pulse diagrams representing the operation
o~ the apparatus of Fig. 2. ` ;
Fig. lL~ is a schematic of a ~irst embodiment of the apparatus ~;
of Fig. 2.
Fig, 15 is a partial schematic of a qecond embodiment of the
apparatus o~ Fig, 2.
Fig. 16 is a diagram representing pulses and signals in the
.,.
apparatus of Fig. 15.
Fig. 17 is an enlarged view of a portion Or the diagram ;~
within the lines 17--~7 of Fig. 16.
Fig. 18 is a schematic view of the apparatus of Fig. 14 as
modified by the apparatus of Fig. 15.
: ~ .
,
'7~i5~4s
Fig. 19 is fl diagram o~ skewed and non-slcewed magnetic
dipoles on a magnetic recording msdium.
Fig. 20 is a diagram of the output o~ a reproduction head
versus an angle B between the head and the axis of magnetic
dipoles detected by the head.
Fig. 21 is a diagram of a skewed head and magnetic dipoles
having an axis describing an angle B relative to the head.
Fig. 22 is a diagram showing the relationship between a
skewed head according to the pre~ent invention and a fraudu-
lently fabricated magnetic card. ~ -
~ETAILED DESCRIPTION
Referring to Fig. 2, the control system of the present
invention is houssd typically in a coin box 21. Coin box or
housing 21 is shown a~ a rectangular boxg which may be mounted
on a vending machine, a laundry or dry cleaning machine or the
like in the same manner as the housings of conventional coin
mechanisms are presently mounted~ Ho~sing 21 shown in Figs. 2 - ` `
and 3 is a rectangular metallic box o~ a type commonly used with
coin acceptors in automatic laundry equipment. A pair of verti-
cally spaced apart openings 22 is formed in the front panel Z3 .
thereof. A feature of the present invention is the fact that
it is adapted to fit into such a housing 21 without modi~ica~
tion, it being understood that other boxes may be substituted.
Indeed, the apparatus of the present invention may be placed in
such conventional housings and thereby effect a substantial
savings in costs of manufacturing. Alternatively, the apparatus -
may be mounted in the interior of a machine in any suitable man~
ner so long as an access thereto is provided ~or the insertion
and removal of a card as hereinafter described. -
Considering the housing 21 of Fig. 2, there is provided in
housing 21, a front panel 27, In panel 27 there is provided a
card-receiving slot 28. Slot 28 is provided for receiving a card
31 on which is enccded a plurality of magnetic signals 33 and,
~. ...
~3'~5~
typically, a su~ficient amount of` identi~iable indicia for
identi~ying the nature of the card and the manner in which it
is used as described more ~ully with respect to Fig~ 1. In
applications other than those involving vending machines and
the likeJ the card 31 may take the ~orm of a tape or other
equivalent structureO
Re~erring to Fig. 1, there is provided on card 31 a strip
32. Strip 32 comprises any suitable material on which magnetic
signals ~ay be encoded. As presently conceived for use in
laundromats, tha magnetic signals encoded on strip 32 correspond
to a ~irst number, identiried a~ a data or i'credit" number 16
and an identification number 17 preceded and followed by a ser-
ies o~ zerols 18 and 19. In addition to the strip 32, there i9
provided on ths face of card 31, a visual indicator 34, such as
an arrow, for showing the direction in which the card 31 is
properly inserted in the slot 28. ~;
The numbsrs 16 and 17 encoded on strip 32 of card 31 serve
to identify t,he card as a valid and usable card. More specifi-
cally, the number 16 corresponds to the number o~ times the card
31 may be used to activate a machine. The number 17 corresponds
~to a predetermined number which serves to identi~y a valid card,
For example, similar cards may be employed ~or activating dif~er-
ent types o~ mqchines having dif~erent operating prices. In .
those cases, the number 16 will prevent inadvertent use of the
wrong card in a machine. The zerots 18 and 19 may be replaced
by other signals ir, ~or example~ an expansion of the ~ields for
the numbers 16 and 17 becomes necessary.
Referring to ~ig. 12, immediately interiorly o~ slot 28,there are provided motor-driven rollers 54 and 72. There i9
also provided a magnetic head 69 for "reading" the magnetic
signals on the card 31. The head 69 i9 also used ~or recording
signals. Positioned in a location to be contacted by the card
31, there are provided a ~orward switch 61 and a li~it or
'~:. . ' ' ': `
.: . .
,
~3 ~ 4
reversing ~witch 66. Coupled to the head 69 and switches 61 and
66 there is provided a control circuit 2Q, which will be deæcrib~
ed hereina~ter in more detail, for controlling a machîne 240
Fitting into the box 21 is a reader 26 having a front panel
27 compatible with panel 23 and formed with a slot 28 f`or recep-
tion o~ a card 31. Also formed in panel 27 is a display window
29 through which the patron may observe the number of "credits~
(i.e., the number of ti~es which a washing machine may be ener-
gized in accordance with the amount paid in the purchase of the
card) at the beginning and at the completion o~ each use o~ the
card~
Reader 26 comprises a top casing 36 horizontally disposed
and having its forward end attached to panel 27 and a bottom
casing 37 there-below and held parallel and spaced apart by one
or more shims 38 so that a gap 39 exists between the casings 36
and 37 which is in registry with the slot 28 and i~ dimensioned
to aocommodate passage of a card 31. Screws l~0 spaced along the
longitudinal edges of casings 36 and 37 pass through holes in
shims 38 and hold casings 36 and 37 assembled. The spacing be-
tween shims 38 i~ equal to the width of card 31. The forward
edge~ of shims 38 curve outwardly to facilitate insert;on of
~ cards into gap 39.
-~ T~op casing 36 has a base 41, upstanding sides 42 and is~ ,
pre~erabl~ closed with a cover 43. Mounted extending trans-
versel~ by means of a clamp 45 fa~tened to base 41 is a miniature
motor and reduction gear combination 46 which i~ pre~erably D.C~
~; operated and reversible. Pinion 47 i9 mounted on the outer end
of the final shaft of motor and reduction gear 46 and pinion 47
drives a train of gears l~8 which are affixed to one of the sides
; 30 42 b~ means of a series of pins 49. The final gear 51 of the
train o~ gears is rotatably mounted on the ~orward end of top ~;~
casing 36 and fits through a slot 52 in the base 41 to engage
similar gear 51 in bottom casing 37 as hereinafter explained.
., . . . ~ , . . .
Gear 51 also turns horizontal transverse shaft 53 on which is
mounted a rubberized roller 54 which fits into gap 39 through
a slot 55 cut in base 41. Sha~t 53 is ~lexibly mounted by means
o~ two mounting brackets 56 shown in detail in Fig. 7. Each
bracket 56 has a spring 57 held down by member 58 and rormed
with a reverse bend 59 into which the sha~t 53 ~its. Screw 60
(Fig. 7) adjusts the roller spring to set the pressure between
the top and bottom rollers 51~, 72. ~he mounting 56 permits the
roller 54 to be moved slightly upward when a card 31 passes
through the gap 39. It exerts sufficient downward force on
roller 54, however, so that the card 31 is driven into the gap ~:~
39. `
Also mounted in top casing 36 is a microswitch 61 having
a switch arm 62 which extends down through a hole 63 in base ~rl ~:
into the gap 39. When a card 31 is inserted through the slot 39
and into the gap 399 it engages arm 62 so that switch 61 starts
motor 46 in ~orward dlrection. Spaced rearwardly on base 41 is
a second microswitch 66 having a switch arm 67 extending into
gap 39 through hole 68. When the card 31 is driven rearwardly
.-. -
~ 20 through gap 39 until it contacts arms 67, switch 66 reverses
:: ~ motor 46 and causes the roller 54 which still engages the card - :to reverse the direction o~ movement thereof and discharge the
card through slot 28~ ~ :
Lower casing 37 has a ba~se 71 in which is rotatably mounted
: bottom roller 72 which is similar to roller 54 and which pro-
jects through a slot 73 ~ormed in base 71 and rotates on a
sha~t 74 which carries the gear 51 mating with the gear 51 of ;
casing 36. Sha~t 74 may be mounted by means o~ mountings 76
which resemble the mountings 56 of casing 36. ~ :
Likewise mounted on panel 27 is a bracket 78 ~or a plurality . `
o~ electronic co~ponents 79 including the power supply and one
or more printed circuit boards (not shown) located in bracket ~ ~.
37.
9 :::
"", , . ` . ' .'' ' . ~
~ 75~ :
Mounted on base 41 is -transducer (head) 69 which i9 located
over the path Or movement of strip 320 The electronic system
used with the head 69 is explained in detail hereinafter in this ~?
specification.
In operation, a card 31 is inserted through the slot 28 and
contacts the switch 61. The switch 61 generates a start signal
on a line 176. The start sign~l generates a motor control signal
on a line 177 causing the rollers 5l~ and 72 to be driven in a
~orward direction~ transporting the card 31 past the head 69
until the card 31 contacts the limit switch 66. When the card
31 contacts the limit switch 66, a reverse signal is generated
on a line 178 ganerating signal on the line 177 causing the
rollers 54 and 72 to be driven in a reverse direction expelling
the card 31 from slot 280 I~ the capacity o~ the card 31 to ;~
activate a machine has been exhausted, the reverse signal, in
that ~instance, could be used to cause the card to be driven into
a refuse container by any suitable means (not shown).
As the card is driven in the ~orward direction, the signals
o~ the card 31 are "read" by the control circuit 20 on a line ~ -`
~20 179. Ir the card is valid and usable in the speci~ic machine
in~which it is inserted and its capacity to activate the machine
has not been exhausted, a start signal is generated on a line 180
~- ~or activating thè machine 24.
~`~ Re~erring to Figs. 13a-f, the magnetic signals encodèd on '~
the strip 32 Or card 31 are pulse-width-modulated and are best ~-
illustratsd b~ representations of pulses of varying wîdths. As
~: .
used herein, eaoh magnetic signal corresponds to a binar~ bit or
number (8-g., a ~one" or a ~zero~). For simplicity, each bit is
considered as occupying a bit cell or ~ield o~ predetermined
, ... :
length. A "one" is chosen to be represented by a pulse occupy- -
ing 1/4 or 25~ of a cell and a "zero" is chosen to be represented ;~
by a pulse occupying 3/4 or 75% of a cell, as shown in Fig. 13a.
Clock pulses, which are generated from the leading edge of the
,:. . . - ~ . ,
.... .. . . . . . . .
~L~37~4
'lone" and "zero" pulse~, as will be clescr;bed in detail beLow,
are chosen to occupy 1~2 or 50~ o~ a cell, as shown in Fig. 13e.
As "one" and "z0ro" magnetic signals are transported past
head 69, positi~,-e and negative pulses corresponding, respective-
1YJ to the leading and trailing edges of the magnetic signals are
generated on khe line 179 as shown in Fig. 13b. From the pulses
of Fig~ 13b there are generated b~ means described below, corres- -
ponding positive and negative pulses, as shown in Figs. 13c and
13d. It will be noted that the negative pulses trail the posi-
tive pulses with which they are associated to a greater or
lesser extent depending on whether the corresponding magnetic
pulses are a "one" or a "zero". As uill become apparent, the
control circuit 20 distinguishes between the "one's" and the
"zero~s" by the correspondence which exists or ~ails to exist `~
between the negative pulses of Fig. 13d and the clock pulses o~
Fig. 13e, as shown in Fig. 13
Referring to Fig. lL,~, there is provided, coupled in parallel
to head 69, a pair o~ voltage comparators 130 and 131. Compara- ~ -
~20 tors 130 and 131 respond, respectively, to the positive and neg-
tive pulses appearing on line 179. Coupled in series to compar-
ators 130 and 131 i9 a pair of one shots 132 and 133.
One shot 132 is provided to output a clock pulse, as shown
in Fig~ 13e, for each o~ the positive pulses o~ Fig. 13b detected
;: ,
by comparator 130. One shot 133 is provided to output a pulseJ ;
as shown in Fig. 13d, corresponding to each o~ the negative
pulses, as shown în Fig. I3b, detected by comparator 131. The
outputs Or one shots 132 and 133 are coupled to the inputs of
a rlip-rlOp 134. The output of one shot 132 is also coupled to
the clock or shift input of a serial-to-parallel shi~t register
135. The data input o~ register 135 is coupled to the output o~
the ~lip-rlOp 134.
Coupled in parallel to the register 135 is a subtract-one
circuit 136, and an identi~ication circuit 137. Circuit 13h is
,: ~ . , , :
~!37Si~4
coupled to that portion of the register 135 which contains the
data or "credit" number 16 for providing an output corresponding
to -that number reduced by a predetermined amount~ such as one.
The circuit 137 i9 coupled to the register 135 ~or both validat-
ing the number 17, which is located in an adjacent portion of the
register and to determine whether the number 16 in the register
is such as to allow an activation of the machina 24~ Ir ~he
numbers 16 and 17 in register 135 are suitable, an enable signal
is generated on a line 138 on the output of circuit 137. In a
typical application, the enable signa] thus generated is applied
to a start flip~flop or a corresponding start circuit 139 to
activate a machine. ;~
In some applications~ it is desirable to visually display ~;
the initial and remaining number of times a machine can be acti~
vated with the same card. Accordingly, there is provided a gate
180 having one input coupled to the register 135 and a second
input coupled to the output of clrcuit 136, d display driver 140 ~ .
and a visual display device 141, such as a conventional seven-
segment display. The display is provided ~or selectively dis-
playing the number 6 in the register 135 or the output o~ the `~
circuit 136 under the control of-a gate snable signal on a line
181 8enerated from a card reverse signal. While the display
device 141 may be positioned in any suitable location, it is
preferably located for viewing through a window 29 in the front ~ -
.. : . .
panel 27 of reader 26 as seen in Fig. 2.
Thus~ in operation~ the initial number 16 is displayed and
thereafter when the reverse signal is generated, the initial ;~
number less one is displayed under the control o~ the gate 180.
In order that the card 31 may be used repeatedly, the mag-
netic signals on the card corresponding to the number 16 arechanged (i.e., reduced) each time the card is used.
To change the number 16 on the card 31, there is provided a
parallel-to-serial shift regi~ter 150. The input to register 150
12
~ ....................................... .. . .
~: . . . .
.
~3~
is provided via two sets of parallel l~nes 151 and 152 coupled~ ;
respectively, to the output of that portion o~ register 135 con-
taining the identification number 17 and the output o~ the
subtract-one circuit 136.
To shi~t the data in register 150 f'or modification of the
number 16 on the card 31 after each use, there is provided an
input circuit 161 for receiving a "card reverse" signal rrom the
card reverse switch 66. Circuit 161 is provided to output a
signal f'or starting an internal clock 162 and enabling a gate
163 and a head driver 164. This signal, as previously describ- ;~
ed al~o ~witches the gate 180 f'or changing the number displayed .
in the device ll~l from the initial number 16 to the number at -
the output Or thc subtract-one circuit. The output Or clock 162
is coupled to a pulse-width modulator 165 and also to the gate
: 163 via a divide-by-rour circuit 166 f`or shifting the data in :~
register 150 serially through the modulator 165. The output of
modulator 165 is coupled to the head clriver 164 either directly .
or bhrough a saw-tooth modulator 167 as shown~ If included, the ~`
saw-tooth modulation o~ the output o~ modulator 165 will shape .:
~ ths:pulse-width modulsted magnetic signals recorded on the card
: 31:in a manner whichJ it is believed, will tend to make much more
dif*icult the analysis o~ the~signals on the card using conven~
tiona~l magnetic transducers and, consequently, will provids a
greater degree o~ security against the rraudulent duplication of : :
the cards 31 by known ~orgery tecùniquss.
Referring to Fig. 15,:there is pra~ided ror use in place of
~, , .
the one shots 132, 133 and 134 of the circuit o~ Fig. 1l~ an al~
ternative decoding circuit 170. In circuit 170 there is provided
a flip-rlop 171 having a set input S ror coupling to the output ~:~
of voltage comparator 130 and a reset input R for coupling to the
output Or voltage comparator 131. To the output o~ rlip-~lop 171,
there is coupled in series to ground a resistor Rl and a capaci- -
tor C. Coupled in parallel with capacitor C is a grounded emitter
:
~L~3~SY4~
transistor Q having a bas~ resistor R2 and an operational ampli-
fier 172. Coupled to the base Or tran~istor Q is the output of
a one shot 173. The input to one shot 173 i5 coupled to the out-
put of voltage comparator 130 via a line 174. The output of
voltage comparator 130 is also coupled via the line 17l~ to the
clock~shift input of the register 135. The data input of regis-
ter 135 is coupled to the output of amplifier 172.
In operation, the output of amplifier 172 and, hence, the
data input to register 135 i9 a ~unction of the potential on
capacitor C at the time of occurrence of each clock pulse.
Referring to Figs. 16 and 17, there is provided a representa- ~ -
tion o~ an output from head 69 wherein the positive-going pulses `~
are equidistantly spaced and the negative-going pulses are dis-
placed from their associated leading positive-going pulse by an
amount corresponding to the binary number 101 a~s described above
with respect to Fig. 13
Re~erring to the wave form of Fig. 16, upon the occurrence
;~ of each positive-going pulse, flip-~lop 171 is set and capaoitor
C begins charging positively a~s shown by the positive-going
portions, A, B, and C of the wave ~orm. Upon the occurrence o~
each negative-going pulse, flip-flop 171 is reset and capacitor ;
C begins charging w~ith an opposite polarity, as shown by the ;`~
nega-tive-going portion~, D~ E, and F of the wave form. Capacitor `~
C continues to oharge negati~ely until the occurrence of the next
succseding clock pulse at which time capacitor C is discharged
through transistor Q and is returned to a re~erence potential,
such as ground, a~ represented by the vertical lines G and H
! `
and the horizontal line of the wave ~orm~
The amount that capacitor C charges positively and negativel~
depends on the relative locations of the positive and negative-
going pulses shown in Fig. 16. When a pulse represents a flone"
the period of positive-going potential on capacitor C is consid-
erably le~s than the same period when the pul~e represents a
~-~3t~5~
~Izero~. Conversel~, the period of negative-going potential
under the same conditions are reversed. Consequentl~, it will
be noted that the charge on capacitor C becomes negative (iOe.,
below a reference potential, such as ground) as shown by the
horizontal line, when the magnetie signal correspond~ to a "o~e",
but remains positive (i.e., above the rererence potential) when
the magnetic signal corresponds to a "zero".
The output of amplifier 172, which tracks the change in
potential on capacitor C, provides, as previously described, the
data input to register L35 under the control Or the elock pulses.
The clock pulse~ also "re~et" the eapacitor C (that is, diseharge
it to a reference potential). The discharging of eapaeitor C is,
however, not instantaneous. As shown in Fig. 17, there is aetu-
ally a brief period during which the output of amplifier 172 does
not change signifieantly with the occurrence of a clock pulse
and, accordingl~, the values of resistors Rl and R2J eapacitor
C and the characteristics o~ transistor Q and amplifier 172 are
chosen to insure sufficient time to clock the data into register
135-
Re~erring to Fig. 18, there is provided a sche~atic of the
circuit o~ Fig. 14 as modified by the circuit o~ Fig. 15. In
: - - .
Fig~18, the principal circuit components shown in block form
comprise conventional integrated circuit components which are
eommerciall~ available under the device type designation pro- ~`
vided from a number of sources as follows~
Device Type Source
3302 Fairchild
9002 Fairchild
7~164 Fairchild
Tl-T6 211 390l~ Fairchild
9374 Fairehild
T7-T10 2N3906 Fairchild
9302 Fairchild
:,
1~3~5~4 . :
961,02 Fairchild
741 Fairchild
9301 Fairchild
9322 Fairchild
2240 EXAR
7L~03 Fairchild
9312 Fairchild -
94 Fairchild
9004 Fairchild ~, -
~ lo 555 Signetics ;~ ~
FND 507 Fairchild
FCD 810 Fairchild
, While each of the principal features of the circuits of
^~ Figs. 14 and 15 are identified in Figo 18 for convenience by ~
corresponding numerical designators, it will be help~ul to note
that the functions of the clock 162, divider 166, pulse-width
modulator 165, gRte 163 and register 150 of Fig. 14 are incor~
porated in and performed by the integrated circuits and
as~sociated circuitry designated 162, L63 and 150 in ~ig. 18. ~ ~-
20~ The cons~olidation of~their functlons as described is a result
o~ the use of integrated ci~cuits. It is, of course, understood
~: ~ . : : : : :
that other oircuit~arrangements may be employed to perform tbe
~same~ function.
Encoder 86 (Pigs. 9-ll) is used to encode cards 31. Such
:
encoder is located at a central point where ~uitable security `-
exists. ~ Top casing 87 i9 closed~with a top cover 88 and mounted
above bottom casing 89 with a gap 91 dimensioned for card 31.~
Bottom oasing 89 hRs a front panel 92 formed with an indicator
window 93 surrounded by a bezel and also having extending there-
.:
through the perimeter of a wheel 94 which may be manually
ad~usted for a give~ number of credits to be encoded onto the
card 31. Within casing 89 is a motor 96 having a shaft 97 here -~
shown as pro~ecting out one side of casing 86 and carrying a
16
~375~4~
drive pulley 98 which, through belt 99~ drives a plurality o~
~peed reduction idler pulLeys 101 mountsd on the outaide o~
casing 86 through belts 102, The ~lnal shaft 103 extends int,o
the casing 89 flnd carries on its inner end a gear 106 which
mates with a gear 118 on front bottom transverse horizontal
shaft 118 on which is mounted bottom roller 119. Shaft 118
carries a gear (not shown) which meshes with gear 107 on top
front transverse horizontal shaft 108, appropriate holes being
formed in the casing so that the gears can mesh. Front top
roller 109 is fixed to shaft 108. Shaft 108 also carries one
of a palr o~ pulleys 111 which are connected together by belt
112, the réarward pulley 111 being fixed on rear top shaft 113
which also carries a rear top roller 114. Rollers 109 and 114
extend down through slots in the bottom o~ casing 87 into the
gap 91 through which card 31 passes. Top shafts 108 and 113 are -
mounted on casing 87 by means o~ supports 116 which resemble the
support 56 shown in Fig. 7, In bottom casing 89 are similar ; ~ ~
supports 117 ~or bottom ~ront sha~t 118 which carries bottom `
ront roller 119 which mates with roller 109. Bottom rear sha~t
Z0 122 is driven ~rom shart 108. Sha~t 122 carries a roller 123
whieh mates with roller 114.
Mounted in easing 87 is a magnetie reeord head (transducer) -
126 which is positioned to magnetically aet upon the strip 32
card 31. A photoeell 127 and exciter lamp mounted in casings -
87 and 89 has an upper element whieh views through a hole 128 in~
casing 87, Motor 96 drives rollers 109, 114, 119, 123 continu-
ously whiIe the en¢oder is operating. The photocell and lamp `~
"
127 operating together indicats when card 31 is in proper po~
tion with respect to head 126 gap and at such time the electrical
eomponents hereina~ter described generate the appropriate binary
number (det~rmined by the manual setting of seleetor switch 94) `
to be reeorded on eard 31.
When the reeording machine is turned on, the rollers 109, 119,
17
~7~
114, L23, whlch draw card 31 into the encoder 86 and push it
out are continuously turning so that any time a card 31 is
inserted, it is lmmediatel~ puLled through the machine. When
the leading edge of card 31 reaches photocell 127, it inter-
rupts light ~rom the exciter lamp and, in turn, activates the
rest of the circuitry. ~ -
The specific circuitry ~or encoding pulse-width-modulated ~,
signals on card 31 in response to the output of photocell 127 -
comprises essentially the same components as are employed in
the signal recording portions of the decoder circuitry described
above with respect to Figs. 14 and 18. The minor dir~erences
which may be noted include the use o~ a digital switch or the
iike ~or setting the desired numbers in an input register cor~
responding to the decoder register 150 and the ~act that the :
encoder does not include the "signaI reading" structure employed -~
in the decoder ror decoding the signals. It should be under~
stood,~ however, that other means well known~to those skilled in
th~ art ma~ be emplo~ed ~or~encoding ~he card 31 with the ~eces-
,.. .
sary~pulse-width-modulated~signals.
~ When pulse-width modulated signals and~other~forms o~
~signals~are enc~aded;on a magnetic recording medium, it is con~
veniqnt,~when;considering~the signals on the medium, such as
card 31, to ~onsider them as oomprising a plurality o~-magnetic
dipoles having an a~is parallel to the axis o~ the recording
head~used for recording thsm. ln~the embodiments o~ the~present
invention described above, the axis of the recording head is
perpendicular to the direction o~ travel o~ the card in the
~; appara~tus. Consequsntly, the axis Or the dipoles encoded on
the card is also perpendicular to the travel o~ the card. This
orientation o~ the magnetic recording and reproduction heads
and the magnetic dipoles encoded on the card with respect to
the travel of the card i9 relatively conventional. However, it
i~ known that certain advantages can be obtained by skewing the
18
3Lq3;3~75~91 `
magnetic recording and reproduction heads relative to -the
direction of travel of the racording medium.
One of the principal advantages in skewing a head is an
improvem~nt in signal discrimination~ Thi~ i~ because the out-
put of a reproduction head varies as a function of the wave
length of the recorded signal and the angle by which the head
is skewed ~rom the axis of the magnetic dipoles forming the
signal. Therefore, the signal level generated from a dipole
having an axis which is not parallel to the head will be low.
Referring to Figo 19, there is shown a length of magnetic
tape 200. Tape 200 corresponds to the magnetic strip 32 on the ~;~
card 31. Ths tape 200 i~ given an assumed direction Or travel
in the direction of the arrow 201. Orientated at an angla per- -
;~ pendicular to this assumed direction is a head 269. Haad 269
correspond~ to the head 69 o~ Figs. l~ and 18 and to a head
similarly orientated which is in the ~ncoder~
In response to the moving strip, l;he head 269 will decode
:
magne;tic dipoles on the strip 200, Those dipoles with an orien-
ta~io~ parallel to the axis o~ the head, such as~ for example~
the dipoles designated 202 and 203 will provide a maximum out~
~put from the head. However, other signals in the form of dipoles,
. ~ ~
~such as dipoles~204, 205~ma~ also be on the strip. ~These~dipoles,
for example, may have an orientation with respeck to the head 2
which describes an angle B. such signals may resu1t, for ex-
ample, from noise in the recording circuitry.
Referring to Fig. 20, there is shown a diagram of the output
signal of-the head 269 versus the angle B. From the diagram it
can be noted that the output signal from the head is ~aximum when
the angle B is zero and falls off sharply with an increasing
;- , ,
;~ 30angle B in either a positive or negative direction. It follows
from the diagram that for a sufficiently large angle B between
:" "
a recorded dipole, such as the dipoles 204 and 205, and the head,
that the output of the head will be ver~ low3 if not zero. It
19
~7~
~urther ~ollows f'rom the ~oregoing that if' the h0ad 269 i9
skewed initially in the recording or encoding o~ signals on
,~ "- :. . .
the card 31, as shown in Fig. 21, th0 output o~ a reading head '
not similarly skew0d will be very low~ if not zero, ror signals
such as dipoles 202 and 203 which are recorded with the conven-
tional perpendicular orientation. Consequently, by skewing the
head 269, signals not having the prererred orientation will be ;`
disori~inated against.
In addition to discriminating against extraneous magnetic
signal~ having an orientation other than parallel to the a~is ~;~
o~ the reading head, the skewing of the reading head to read
intentionally skewed recorded signals has the further advantage
of reducing the usability o~raudulently duplicated cards in
the apparatus o~ the present~invention. This advantage arises
~rom the nature o~ the technlques most co~monly employed ~or;
that purpose. The techniques re~ferred to typically employ a
transf'er process in which the signals on one medium are trans~
f~erred to~a se~oond medium. During~the trans~er process, the
signals~resulting on the second medium are the mirror image o~
20~ ~the~signaLs;~on thé ~irst~ medium with a;corresponding re~versal
in~the~polarity~oP ths~signaIs.
~ Re~erring to Fig. ~2?j: there is shown a duplicated card ~ab~
- ri~cated acoording to the techniques described in which the
orientation and polarity or ths~dipole~s 2O4~and 205 are;the
mirror~i~age of the same dipoles in Fig.~ 19. Dipoles 202 and
203 are omitted ~for ciarity.~ When a card usable in the pre~ent~
invsntion is duplicated~using these teohniques~and th~reartsr
sn sttsmpt~is~msds to use ths~oard in ths~spparatus o~ the
present invention, the angle between the~ axis Or the~head and~
the axis Or the duplicated dipoles, as~seen in ~ig. 22, is such
that ~or a given angle B no signal lS genersted in the head. ;~
Consequently, tha employment o~ skewed recording and reproduction i~
heads in the present invention will provide an effective means
, .
~ ~
.,
, ` : . . ~ : '' : ` '' ' -`: . :j
~3~7S~
ror preventing at least one form of unau-thorized use Or the
apparatus.
While a number of embodiments Or the prexent invention have
been described and a number Or modifications suggested, it is ~ :
understood that still other changes are possible and will un- ~
doubtedly occur to those skilled in the art without departing .. ~
from the spirit and scope of the present invention. ;-.. : .
Accordingly, it is important that the description provided
herein be considered only as illustrative of pre~erred embodi- - -
ments and that it not be construed as limiting the invention, .. .
the scope Or which is intended to be determined b~ the clai~
hereinafter provided.
,
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..,i,, ~,. ...
