U.S. patent number 3,656,615 [Application Number 05/079,456] was granted by the patent office on 1972-04-18 for receiving and transporting apparatus for currency.
This patent grant is currently assigned to The Vendo Company. Invention is credited to James F. Ptacek.
United States Patent |
3,656,615 |
Ptacek |
April 18, 1972 |
RECEIVING AND TRANSPORTING APPARATUS FOR CURRENCY
Abstract
A bill transport of a currency acceptor conveys a bill inserted
thereinto along a path of travel having a sharp initial bend
followed by a rectilinear stretch defined by an elongated, narrow
channel. The bend is formed by rollers at the inside of the bend
opposed by endless belts presenting the outside of the bend. A
validity test station is located intermediate the ends of the
cannel, and the bill is held flat as it is advanced along the
channel by two rows of opposed pairs of rollers projecting into the
channel and receiving the bill adjacent its longitudinal edges. A
constant speed transport drive is provided by a direct current
motor governed by a centrifugal chopper. Failure to maintain proper
operating speed due to jamming or the like results in the
application of an unchopped voltage to the motor, causing voltage
to build up across a capacitor to a level which fires a
programmable unijunction transistor that, through associated
switching circuits, reverses the polarity at the motor input
connections to reverse the drive and return the bill to the insert
opening. Such switching circuits are also operated by the validity
tester to return a bill found to be invalid.
Inventors: |
Ptacek; James F. (Kansas City,
MO) |
Assignee: |
The Vendo Company (Kansas City,
MO)
|
Family
ID: |
22150681 |
Appl.
No.: |
05/079,456 |
Filed: |
October 9, 1970 |
Current U.S.
Class: |
209/534; 226/25;
271/259 |
Current CPC
Class: |
G07F
7/04 (20130101) |
Current International
Class: |
G07F
7/00 (20060101); G07F 7/04 (20060101); B07c
003/02 () |
Field of
Search: |
;209/73,DIG.2,75,74
;226/25 ;271/47,57,DIG.9 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schacher; Richard A.
Claims
Having thus described the invention, what is claimed as new and
desired to be secured by Letters Patent is:
1. In a currency acceptor:
means presenting an insert opening for receiving a bill to be
tested;
a transport adjacent said opening for conveying an inserted bill
along a path of travel having a substantially rectilinear
stretch,
said transport being provided with structure for holding the bill
flat during movement thereof through said stretch;
a test station intermediate opposed ends of said stretch having
means for sensing physical properties of the bill as it traverses
said stretch;
power means coupled with said transport for driving the latter at a
substantially constant speed as the bill is conveyed through said
stretch past said station for testing; and
control and validity determining means operably coupled with said
bill sensing means and said power means for reversing the drive to
the transport to return the bill to said insert opening either in
response to a decrease in the speed of the transport indicative of
an overload condition, or if the bill is invalid.
2. In a currency acceptor as claimed in claim 1,
said structure presenting a narrow channel defining said stretch,
and having rotatable means projecting into said channel for
frictional engagement with the bill,
said power means being connected with said rotatable means for
rotating the latter to advance the bill along said channel.
3. In a currency acceptor as claimed in claim 1,
said structure presenting a narrow channel defining said stretch,
and having opposed pairs of rollers projecting into said channel
for frictionally engaging the bill therebetween,
said power means being connected with one roller of each of said
pairs thereof for simultaneously rotating the same to advance the
bill along said channel.
4. In a currency acceptor as claimed in claim 3,
said channel being elongated in the direction of advancement of the
bill therealong,
said pairs of rollers being arranged in two rows adjacent
respective longitudinal edges of the bill as it is advanced along
said channel,
the roller pairs of each row being spaced apart longitudinally of
said channel.
5. In a currency acceptor as claimed in claim 1,
said transport having corner means presenting a bend in said path
between said insert opening and said stretch,
said corner means including a roller member at the inside of said
bend and an endless belt member trained over said roller member to
present the outside of said bend,
said members being disposed to frictionally receive the bill
therebetween,
said power means being connected with one of said members to drive
the latter and thereby advance the bill around the bend.
6. In a currency acceptor as claimed in claim 5,
said members presenting a bill-receiving nip adjacent said insert
opening,
there being a slot communicating said opening with said nip to
permit feeding of the bill to the nip.
7. In a currency acceptor as claimed in claim 1,
said power means including an electric motor having an output
shaft,
said control and validity determining means including means
responsive to said motor for sensing the speed of said shaft, and
circuitry coupled with said speed sensing means and said motor for
effecting a reversal of the direction of rotation of said shaft
when the speed thereof falls below a predetermined operating
speed.
8. In a currency acceptor as claimed in claim 1,
said power means including an electric motor having electrical
input connections and an output shaft,
said control and validity determining means including switch means
responsive to said motor and operable to change from a normal
condition to an operated condition when the speed of said shaft
exceeds a predetermined operating speed, and circuitry coupled with
said input connections and said switch means for applying voltage
to said input connections, and said voltage having a chopped
characteristic in response to changes in the condition of said
switch means, whereby to maintain the shaft at substantially said
predetermined operating speed to thereby drive the transport and
convey the bill at substantially constant speed.
9. In a currency acceptor as claimed in claim 8,
said circuitry having means responsive to said voltage for
effecting a reversal of the direction of rotation of said shaft
when the speed thereof falls below said predetermined operating
speed.
10. In a currency acceptor as claimed in claim 8,
said motor being sensitive to the polarity of the voltage applied
to said input connections thereof,
said circuitry having a trigger capacitor, a charging circuit for
said capacitor coupled with said input connections, and
electrically responsive switching means coupled with said capacitor
and responsive to a predetermined build-up of voltage thereacross
for reversing the polarity of the voltage applied to said input
connections, whereby the motor is reversed unless the voltage
supplied thereto continues to be chopped.
11. In a currency acceptor:
means presenting an insert opening for receiving a bill to be
tested;
a transport adjacent said opening for conveying an inserted bill
along a path of travel having a substantially rectilinear
stretch,
said transport being provided with structure for holding the bill
flat during movement thereof through said stretch,
said structure presenting an elongated, narrow channel defining
said stretch, and having rotatable means projecting into said
channel for frictional engagement with the bill;
a test station intermediate opposed ends of said channel having
means for sensing physical properties of the bill as it traverses
said channel; and
power means coupled with said rotatable means for driving the
latter at a substantially constant speed to advance the bill along
said channel past said station for testing,
said transport having corner means presenting a bend in said path
between said insert opening and said channel,
said corner means including a roller member at the inside of said
bend and an endless belt member trained over said roller member to
present the outside of said bend,
said members being disposed to frictionally receive the bill
therebetween,
said power means being connected with one of said members to drive
the latter and thereby advance the bill around the bend.
12. In a currency acceptor as claimed in claim 11,
said rotatable means comprising opposed pairs of rollers for
frictionally engaging the bill therebetween,
said power means being connected with one roller of each of said
pairs thereof for simultaneously rotating the same.
13. In a currency acceptor as claimed in claim 12,
said pairs of rollers being arranged in two rows adjacent
respective longitudinal edges of the bill as it is advanced along
said channel,
the roller pairs of each row being spaced apart longitudinally of
said channel.
14. In a currency acceptor as claimed in claim 11,
said members presenting a bill-receiving nip adjacent said insert
opening,
there being a slot communicating said opening with said nip to
permit feeding of the bill to the nip.
15. In a currency acceptor:
means presenting an insert opening for receiving a bill to be
tested;
a transport adjacent said opening for conveying an inserted bill
along a path of travel within the acceptor;
a test station adjacent said path having means for sensing physical
properties of the bill as it travels along said path;
an electric motor having electrical input connections and an output
shaft mechanically coupled with said transport for driving the
latter to advance the bill past said station for testing;
means responsive to said motor for sensing the speed of said shaft;
and
circuitry coupled with said input connections and said speed
sensing means for effecting a reversal of the direction of rotation
of said shaft when the speed thereof falls below a predetermined
operating speed, whereby to return the bill to said insert opening
in the event of an overload or the like.
16. In a currency acceptor as claimed in claim 15,
said speed sensing means comprising switch means operable to change
from a normal condition to an operated condition when the speed of
said shaft exceeds said predetermined operating speed,
said circuitry applying voltage to said input connections of the
motor, and said voltage having a chopped characteristic in response
to changes in the condition of said switch means, whereby to
maintain said shaft at substantially said predetermined operating
speed to thereby drive the transport and advance the bill at
substantially constant speed.
17. In a currency acceptor as claimed in claim 16,
said circuitry having means responsive to said voltage for
effecting said reversal of the direction of rotation of said shaft
when the speed thereof falls below said predetermined operating
speed.
18. In a currency acceptor as claimed in claim 16,
said motor being sensitive to the polarity of the voltage applied
to said input connections thereof,
said circuitry having a trigger capacitor, a charging circuit for
said capacitor coupled with said input connections, and
electrically responsive switching means coupled with said capacitor
and responsive to a predetermined build-up of voltage thereacross
for reversing the polarity of the voltage applied to said input
connections, whereby to reverse the motor to effect said reversal
of the direction of rotation of said shaft unless the voltage
supplied to the motor continues to be chopped.
Description
CROSS-REFERENCES
See my concurrently filed copending application, Ser. No. 79,444
filed Oct. 9, 1970, entitled "Currency Testing System", and the
copending application of Boley A. Andrews and James F. Ptacek, Ser.
No. 886,530, filed Dec. 19, 1969, and entitled "Combined Optical
and Magnetic Transducer".
This invention relates to improvements in bill transporting
apparatus utilized in currency acceptors or validators.
It is an important object of the present invention to provide a
compact and easily serviceable currency acceptor for vending
machines, bill changers and the like, and to therefore provide a
bill transport of relatively uncomplex mechanical design capable of
conveying the bill under test in a flat disposition and at constant
speed along a rectilinear path of travel past the test station for
validity determination.
Another important object of this invention is to provide a bill
transport as aforesaid which causes the bill to follow a total path
of travel from insertion to acceptance that is arranged to maximize
the compactness of the acceptor while still facilitating the
servicing thereof.
Still another important object of the invention is to provide a
currency acceptor wherein the transport drive thereof immediately
reverses to return the deposited bill in the event of an overload
condition such as might be caused by jamming or failure of the
depositor to quickly release the bill, as well as in the event that
the bill is determined to be invalid.
Furthermore, it is an important object of the invention to provide
control circuitry for a bill transport which maintains an electric
drive motor for the transport at a substantially constant operating
speed, and which is capable of electrically sensing a decrease in
such speed indicative of an overload and effecting reversal of the
motor in response thereto.
In the drawings:
FIG. 1 is a side elevational view of the acceptor unit of the
present invention;
FIG. 2 is a rear elevational view of the unit showing the same with
the electronics module removed therefrom;
FIG. 3 is a front view of the electronics module as seen removed
from the acceptor unit;
FIG. 4 is a vertical sectional view taken along line 4--4 of FIG.
2;
FIG. 5 is a front view of the unit on a reduced scale, a cabinet
wall on which the unit is mounted being shown fragmentarily;
and
FIG. 6 is an electrical schematic diagram showing control circuitry
for the drive motor of the bill transport.
Referring initially to FIGS. 1-5, the currency acceptor is broadly
denoted by the numeral 10 and has a housing that includes a pair of
spaced sidewalls 12 and a front panel 14, the acceptor 10 being
shown in FIG. 5 as it would appear mounted on a wall 16 of the
cabinet of a vending machine, bill changer or the like.
Approximately the lower half of the front panel 14 slopes inwardly
to, in cooperation with an upwardly extending ramp 18, present an
insert opening 20 for receiving a bill. In FIG. 4, a bill to be
tested by the acceptor is illustrated at 22 shortly after
advancement thereof into the acceptor is commenced by a bill
transport 24 to be subsequently described in detail.
The drive components of the bill transport 24 are shown in FIGS. 1,
2 and 4. The acceptor housing is provided with a backplate 26 which
is elongated and steeply inclined, the upper end of the backplate
26 being rounded to smoothly merge with the rounded upper end of
the ramp 18. Four rotatable shafts 28, 30, 32 and 34 are vertically
spaced in front of the backplate 26 and extend horizontally between
the sidewalls 12. Referring first to the uppermost shaft 28, a pair
of friction rollers 36 are rigid with shaft 28 and spaced apart so
as to be located adjacent respective sidewalls 12 as is clear in
FIG. 2. Clearance openings are provided in the backplate 26 and the
ramp 18 to permit the circumferential, frictional surfaces of the
rollers 36 to extend through both the backplate 26 and the ramp 18
for a purpose to be discussed hereinafter. In similar fashion, a
pair of friction rollers 38 rotate with shaft 30, a pair of
friction rollers 40 are provided on the shaft 32, and the lowermost
shaft 34 is likewise provided with a pair of friction rollers 42.
As is clear in FIG. 2, two rows of rollers are presented, each of
which is adjacent a corresponding sidewall 12. As will be
appreciated hereinafter, the rollers 36-42 are thus disposed
adjacent the longitudinal edges of a bill being conveyed by the
transport 24.
The left ends of the rotatable shafts 28-34 project from the left
sidewall 12 as viewed in FIG. 2 and are provided with pulleys 44,
46, 48 and 50 respectively. A drive motor 52 is located behind the
panel 14 (together with associated power supply components which
are not illustrated) and has an output shaft 54 provided with a
drive pulley 56. A stationary cross shaft 58 extends horizontally
between the sidewalls 12 just behind the lower end portion of the
front panel 14, the cross shaft 58 serving to rotatably mount a
reduction pulley 60 driven by a belt 62 trained around the drive
pulley 56 and a larger diameter section of the reduction pulley 60.
A second belt 64 is then trained around a smaller diameter section
of the pulley 60, an idler 66, pulleys 44 and 46, and idler 68, and
pulleys 48 and 50. Since the pulleys 44-50 are of the same size, it
is apparent that the rollers 36-42 (all of equal diameter) are
driven simultaneously in the same direction at the same speed.
A pair of horizontally spaced, generally J-shaped side plates 70
support a J-shaped guide plate 72 therebetween which defines the
general outline of a sharp bend in the path of travel of the bill
22. More particularly, a top roll 74 extends horizontally between
the side plates 70 and is rotatably supported thereby. A pair of
pulleys 76 are located forwardly and downwardly from the roll 74
and are interconnected for rotation in unison about a horizontal
axis. Likewise, a pair of pulleys 78 are spaced directly below the
top roll 74 and also rotate in unison about a horizontal axis. A
pair of endless belts 80 are trained around the roll 74 and
respective pulleys 76 and 78 as is clear from a comparison of FIGS.
2 and 4. The stretches of the belts 80 between the pulleys 76 and
78 are held against the friction rollers 36 thereby presenting a
nip for receiving the leading edge of the bill 22 upon insertion of
the latter into the opening 20. In this regard, note that a slot 82
is defined between the guide plate 72 and the upper end portion of
the ramp 18 for the purpose of guiding the leading edge of the bill
22 into the nip formed by the opposed rollers 36 and belts 80.
From the foregoing, it may be appreciated that the roll 74, pulleys
76 and 78, and belts 80 form a corner assembly which cooperates
with the rollers 36 to define a sharp bend in the path to be
travelled by the bill 22. The entire assembly may be removed as a
unit to facilitate servicing, thus the lower, forward ends of the
side plates 70 may be slotted as shown to receive the cross shaft
58 and thereby key the assembly into its proper position. A small
electric lamp 84 is disposed between the side plates 70, and the
guide plate 72 has an aperture 86 to permit light to be directed
from the lamp 84 toward an opening 88 in the ramp 18 and a
corresponding opening 90 in the backplate 26.
An electronics module 92 includes an elongated, channel-shaped
support plate 94 for the circuit board thereof and other electrical
and mechanical components to be described. Four lugs 96 project
from the sides of the support plate 94 and are received by brackets
98 to mount the module 92 with the front face 100 of the support
plate 94 in closely spaced, parallel relationship with the
backplate 26. Accordingly, the opposed, planar faces of the closely
spaced plates define an elongated, narrow channel 102 into which
the bill is fed after traversing the bend described hereinabove.
The module 92 is held in the brackets 98 by a latch 104 associated
with one of the brackets 98, thus the module 92 may be readily
detached from the acceptor unit for servicing or to facilitate
cleaning of the surfaces in the channel 102 subject to continual
contact by transported bills.
As is clear in FIGS. 3 and 4, a pair of idler rollers 106 project
through clearance openings in support plate 94 and engage
corresponding friction rollers 38. Likewise, a pair of idler
rollers 108 and a pair of idler rollers 110 engage friction rollers
40 and 42 respectively. Accordingly, the bill traversing the
channel 102 will be sandwiched between each friction roller and its
opposing idler roller. A test station is provided intermediate the
ends of the channel 102 as illustrated by the transducer head 112
projecting through the front face 100 of the support plate 94, and
the electric lamp 114 opposing the head 112 and carried by the
backplate 26. The head 112 shown herein is a combined optical and
magnetic transducer as disclosed in the above-identified
application of Boley A. Andrews and James F. Ptacek, Ser. No.
886,530, but other means of sensing the physical properties of the
bill may be employed as appropriate to the particular validity
testing system embodied in the electronics of the module 92. A
suitable testing system is disclosed in my above-identified
copending application, Ser. No. 79,444, wherein input information
in the system logic includes sensing the presence of the leading
edge of the bill upon insertion into the slot 82 and sensing such
leading edge again at the lower end of the channel 102. To this
end, a phototransistor 116 in the module 92 is disposed to receive
light emanating from the lamp 84, and a phototransistor 118 is
positioned to receive light emanating from an electric lamp 120 at
the lower end of the channel 102.
Referring to FIG. 6, the motor 52 is illustrated schematically
together with its output shaft 54. The motor 52 is of the
reversible, direct current type and has a pair of input connections
122 across which a direct voltage is applied. The leads labeled +24
V and -24 V represent power leads from a 24 volt DC supply
comprising the power source for the motor 52. The control circuitry
is operated at lower voltage levels as indicated by the supply
leads labelled +15 V and -15 V.
A governor is provided by a centrifugal contact 124 which rotates
with the motor shaft 54. The contact 124 is in the nature of a
normally closed switch which opens under centrifugal force when the
shaft 54 exceeds a predetermined operating speed. The switch 124 is
serially connected in a lead 126 which branches at 128 and is
connected to the base of an NPN emitter follower transistor 130. A
second branch 132 extends to the base of a PNP transistor 134 which
is also operated as an emitter follower. The collectors of the
transistors 130 and 134 are connected to the +24 V and -24 V leads
respectively, and their emitters are connected to the upper input
connection 122 of the motor 52. The lower input connection 122 is
at circuit ground as indicated by the symbol.
A lead 136 extends from the upper input connection 122 to a
resistor 138 that is in series with a trigger capacitor 140. The
lead 136 and resistor 138 constitute a charging circuit to the
capacitor 140, the latter being connected in parallel with a
programmable unijunction transistor 142 and a series cathode
resistor 144. Both the lower end of the resistor 144 and the lower
plate of the capacitor 140 are at ground potential.
A resistor 146 and a series diode 148 are connected from the upper
plate of the capacitor 140 to the lead 136 and present a discharge
path for the capacitor 140, the resistance of the resistor 146
being substantially less than the resistance of the resistor 138. A
series connected diode 150 and capacitor 152 are connected across
the capacitor 140, and a resistor 154 is connected in parallel with
the capacitor 152.
A silicon controlled rectifier 156 has its gate directly connected
to the cathode of the PUT 142, and a lead 158 extends to the gate
of the SCR 156 from the validator circuitry represented by the
block 160 having the legend "validity tester". The function of the
SCR 156, upon triggering thereof, is to reverse the drive to the
transport 24 to return a deposited bill to the insert opening 20,
either in response to an overload condition (to be discussed) or a
determination by the validity tester 160 that the bill is invalid.
The SCR 156 is coupled with switching circuitry including three PNP
switching transistors 162, 164 and 166 having their emitters
connected to the +15 volt power lead, and a NPN switching
transistor 168 having its emitter connected to the -15 volt power
lead. A normally open switch 170 through a resistor 172 connects
the base of the transistor 164 and the collector of the transistor
166 to ground upon closure thereof, and is diagrammatically
illustrated as operated by the validity tester 160. The lead 126 to
the governor switch 124 is connected to the collector of the
transistor 164 via resistor 174, and to the collector of the
transistor 168 via resistor 176. A reset lead is shown at 178
connected to the anode of the SCR 156 by a coupling capacitor
180.
OPERATION
A bill, such as indicated at 22 in FIG. 4, is placed in the insert
opening 20 and its leading edge is manually fed into the slot 82.
The proper disposition of the bill 22 may be indicated to the
depositor by providing the surface of the ramp 18 with a properly
oriented facsimile of the bill (not shown). When the bill has been
inserted sufficiently to cover the opening 88 and thereby block the
light normally impinging on the phototransistor 116, the validity
tester 160 commences operation of the transport 24, such action
being represented in FIG. 6 by the closure of switch 170. The
switching transistor 164 now conducts and positive voltage is made
available on lead 126. This places the emitter follower transistor
130 in conduction to thereby supply the motor 52 with positive
voltage at its upper input connection 122. This is the forward
drive condition. At this time switching transistors 162, 166 and
168 are nonconducting.
It may be appreciated that the bill 22 immediately traverses a
sharp bend around the two rollers 36 defining the inside of such
bend. The outside of the bend is presented by the two endless belts
80, the bill 22 being received in the nip presented by the rollers
36 and opposing belts 80. As the leading edge of the bill 22 passes
the bend as depicted in FIG. 4, it enters a rectilinear stretch
defined by the narrow channel 102. Those portions of the bill 22 in
the channel 102 remain flat due to the confines of the narrow
channel and the nature of the drive therein. In this respect, it
should be noted that the opposed rollers 38 and 106 are adjacent
the longitudinal edges of the bill as are the later roller pairs
40, 108 and 42, 110. With all of the rollers 38, 40 and 42 being
driven at the same speed, drive is applied to the bill without
causing bunching or otherwise significantly distorting the bill
from a flat orientation along a rectilinear course. Accordingly,
the bill is essentially flat and straight as it passes the test
station and is sensed by the head 112. From the input information
derived from the head 112, a validity determination is made and, if
the bill is found valid, the transport drive is not disturbed. This
results in ultimate acceptance of the bill as it emanates from the
lower end of the channel 102 and passes into a suitable receptacle
(not shown). If the bill is found to be invalid, a reject pulse
appears along lead 158 to trigger the SCR 156, causing reversal of
the transport drive in a manner to be subsequently explained.
When the SCR 156 is placed in conduction, the bases of the
switching transistors 162 and 166 go negative with respect to the
emitters thereof, thereby placing transistors 162 and 166 in
conduction and turning off the transistor 164. A voltage divider is
formed by a pair of series connected resistors 182 and 184
connected between the collector of transistor 162 and the -15 volt
supply lead. Since the base of transistor 168 is connected to the
common connection of the resistors 182 and 184, such base goes
positive with respect to the emitter of transistor 168 to render
the same conductive. Accordingly, instead of being connected
through transistor 164 to the +15 volt supply lead, the lead 126 is
now connected to the -15 volt supply lead through the transistor
168. Therefore, emitter follower 134 now conducts instead of
emitter follower 130 thereby applying negative voltage to the upper
input connection 122 of the motor 52. With the transport drive now
reversed, the bill is returned to the opening 20, whereupon the
motor control circuitry is reset by a negative voltage applied to
reset lead 178 by the validity tester logic. The negative reset
pulse appearing at the anode of the SCR 156 momentarily interrupts
current flow therethrough to effect the resetting function.
Attention is now directed to the governor switch 124. As the motor
shaft 54 begins to exceed a selected operating speed, the switch
124 opens to momentarily remove excitation from the motor input
connections 122. This results in a slight decrease in shaft speed,
whereupon the switch 124 recloses and remains closed until the
shaft once again exceeds the selected operating speed. Accordingly,
the switch 124 functions as a centrifugal chopper and produces a
voltage waveform illustrated at 186 for the forward operating
direction. Note the notches 188 caused by the chopping action and
occurring during times that the switch 124 is open.
As long as the chopped waveform 186 is supplied to the motor 52,
the capacitor 140 alternately charges and discharges. However, in
the event that an overload condition should occur in the transport
drive, such as by jamming of the bill or failure of the depositor
to quickly release the bill once it is pulled onto the transport
drive, the speed of the shaft 54 decreases and normal operating
speed is not maintained. Under such condition the switch 124
remains closed and the voltage is no longer chopped, thus voltage
is permitted to build up across the capacitor 140 until the firing
potential of the PUT 142 is reached. When the PUT 142 conducts, the
SCR 156 is triggered by the voltage drop across resistor 144. This
immediately causes reversal of the transport drive as in the
previous case where the bill was found to be invalid. Once the bill
is returned to the insert opening 20, the circuitry is reset as
before.
From the foregoing, it may be appreciated that the speed at which
the bill is advanced by the transport 24 is maintained constant to
facilitate accurate sensing of the physical properties of the bill
by the head 112 at the test station. Currency testing systems
commonly respond to lines of magnetic ink appearing on the bill,
thus constant bill speed is important if the spacing between such
lines is to be ascertained by a frequency responsive system. In the
present invention a test will not be run other than at the
preselected bill speed, since greater speeds are prevented by the
governor action and lesser speeds cause the bill to be returned to
the depositor.
Manifestly, the speed test that is performed as discussed above
must be delayed until the motor shaft 54 has an opportunity to
reach operating speed. Accordingly, the capacitor 152 is provided
and charges during the start-up voltage surge to prevent triggering
of the PUT 142 and delay the speed test in accordance with the RC
time constant of capacitor 152 and resistor 154.
* * * * *