[0001] This invention relates to a physical shock detector for detecting a physical shock
to a machine. In particular, the invention relates to a physical shock detector for
use with an amusement machine of the type in which a user attempts to obtain a payout
of coins from the machine.
[0002] A preferred feature of such machines is a mechanism to ensure that a user will not
obtain an unwarranted payout of coins by hitting or otherwise physically disturbing
the machine. This is a particularly significant problem in coin pusher amusement machines:
the present invention is particularly relevant to such machines, though it should
be noted that it is not restricted to use in or with such machines.
[0003] Coin pusher amusement machines are illustrated in, for example, GB-A-2124913 and
GB-A-2272383. Such machines generally include a horizontal playfield, on which many
coins are distributed. In the context of this specification, the term "coins" should
be understood to include any similar disks or tokens or the like. The pattern of coins
on the playfield is periodically disturbed by a coinpusher, which may be in the form
of a movable stage which periodically sweeps across part of the playfield surface.
Coins are pushed towards the edge of a playfield and some may be pushed over the edge
into a "win chute". From this win chute, these coins pass into a receptacle to be
recovered by the user of the machine. The user is able to introduce additional coins
into the machine. These additional coins may pass onto the playfield surface directly
or via another surface of the coin pusher. The object of the user of the machine is
to insert such additional coins with the hope that as a result a larger number of
coins will be pushed over the edge into the win chute. A problem for the owner of
the machine is to prevent an unearned dispensation of coins down the win chute to
the receptacle. Such an unearned dispensation may be caused by the user hitting the
machine to knock coins off the playfield into the win chute.
[0004] One means of preventing unearned dispensation of items from coin-operated machines,
in particular coin-pusher machines, is disclosed in GB-A-2250368. A gate is positioned
in the win chute. This gate in its normal position will divert coins which fall down
the win chute into an internal cash box inaccessible to the user. When a user inserts
additional coins, the gate means is moved to a second position which permits coins
falling down the win chute to be recovered by the user.
[0005] A mechanism of this type can be used in conjunction with a sensor for detecting a
physical shock to the machine. If the machine is given a physical shock, a signal
is produced by the sensor. This signal is passed to a central control section which
acts to move the gate means to divert any coins into the internal cash box, regardless
of whether or not coins are fed into the machine. Accordingly, if the user of the
machine hits or rocks the machine in an attempt to cause coins to drop into the win
chute, any coins that do drop as a result of this action will be deposited in the
internal cash box and not made available to the user.
[0006] A known form of detector for this purpose comprises a pair of phosphor bronze contact
strips. These are mounted close to each other in parallel and fastened together at
one end, but electrically isolated from each other. A bob weight is attached to one
of the contact strips. A wire leads away from each contact, the whole assembly being
mounted on a small rectangle of wood. This wooden rectangle is then rigidly mounted
to the inside of the cash box door, with the contacts oriented vertically such that
the free ends are at the bottom. A physical shock to the machine, for example, a thump
with the palm of the hand, would then be sufficient to close the contacts for a moment.
This provides a signal detectable by the control section, which is configured to take
appropriate action. The chosen procedure on detection of a physical shock could comprise
operation of a gate in the win chute to prevent dispensation of coins to the user
as described above, and may also or alternatively comprise an alarm.
[0007] Contacts of this type require individual adjustment and are especially sensitive
to the handling that they receive. Carelessly handled contacts may require readjustment
and as a result may not function in a satisfactory and reproducible manner.
[0008] The present invention provides a solution to this problem of the prior art by provision
of a reliable sensor which provides reproducible results. This sensor is also of low
cost and of simple construction.
[0009] According to the present invention, there is provided a means for sensing a physical
shock to an amusement machine of the type in which a user attempts to obtain a pay
out of coins from the machine, said means for sensing a physical shock comprising:
a piezoelectric sensor for mounting to the machine for detection of a physical shock
thereto; and
signal provision means, having an input for receiving signals from the piezoelectric
sensor and an output for providing signals to a control section of the machine when
a physical shock is detected.
[0010] The invention also provides an amusement machine comprising means for sensing a physical
shock as described above, and further comprising a control section and means controlled
by the control section for diversion of coins to an internal cash box when a physical
shock is detected.
[0011] An embodiment of the invention is described below, by way of example, with reference
to the accompanying drawing, in which:
[0012] Fig. 1 shows a circuit diagram of a physical shock sensing means according to the
invention.
[0013] Figure 1 shows a means for sensing a physical shock to an amusement machine of the
type in which a user attempts to obtain a pay out of coins from the machine, this
means for sensing a physical shock comprising a piezoelectric sensor (1) for mounting
to the amusement machine for detection of a physical shock thereto. It also comprises
a signal provision means (2) which has an input at SKT1 for receiving signals from
the piezoelectric sensor and an output at SKT2 for providing signals to a control
section of the amusement machine when a physical shock is detected.
[0014] The piezoelectric sensor (1) is mounted to the amusement machine. A particularly
appropriate location for the sensor is on the inside of the door of the cash box of
the machine. It is desirable for the piezoelectric sensor to be mounted securely but
such that it is not cushioned from any physical shock experienced by the machine.
An appropriate way to mount the piezoelectric sensor is to bond it to the inside of
the cash box door with double-sided tape. A suitable form of tape is "Scotch VHB"
tape, which has a high bonding strength but does not provide any significant degree
of cushioning to shock. The piezoelectric sensor (1) is advantageously a conventional
sensor of the ceramic disc type, although alternative forms of piezoelectric sensor
could be employed.
[0015] It is desirable to mount the signal provision means circuitry close to the piezoelectric
sensor. This circuitry is advantageously formed on a printed circuit board which is
then mounted on pillars nearby.
[0016] The circuit for the signal provision means (2) is shown in Figure 1. The piezoelectric
sensor (1) is connected to a SKT1. If the machine is subjected to a physical shock,
the piezoelectric sensor will be stressed by the shock and will emit a voltage signal
as a result. This provision of voltage with time results in a pulse. This voltage
is dropped across a potentiometer (11). The sensitivity of the circuit is adjusted
by adjustment of this potentiometer, this adjustment determining the size of the signal
received as an input by a first operational amplifier (12) for a given sensor signal
size. The signal amplified by this first amplifier (12) is shaped by resistors R3
and C1 and then fed to a second operational amplifier (13). The amplified signal then
passes through a light emitting diode (14) to a switching transistor (16). Between
the output of the second operational amplifier (13) and the input of the light emitting
diode (14) there is a pull up resistor (15). The function of the light emitting diode
(14) is to provide a visual indication of when there has been a sufficient signal
to provide an output to the control means of the amusement machine. This is of assistance
in adjustment of the potentiometer (11) to obtain a desired degree of sensitivity.
Alternatively, if the circuit response has already been evaluated or determined, the
potentiometer (11) can be replaced by an appropriate pair of resistors and the light
emitting diode (14) can be removed from the circuit. The source of the transistor
(16) is connected to pin 2 of SKT2, which is connectable to the control section of
the amusement machine. Pins (1) and (3) are for connection to the positive supply
and earth respectively. Pin (2) is connected such that if the gate signal at transistor
(16) is sufficient to make the source drain channel conducting, pin 2 will be effectively
grounded. Pin 2 is therefore adapted to provide a logic signal indicative of a physical
shock of above a predetermined magnitude threshold being suffered by the machine.
[0017] When a signal is received by the amusement machine through pin 2 of SKT2, appropriate
known means can be employed to prevent dispensation of coins to the user or to alert
the machine operator. An alarm can be sounded, or, alternatively, a gate in the win
chute can be operated such that coins are diverted automatically into the internal
cash box.
1. Means for sensing a physical shock to an amusement machine of the type in which a
user attempts to obtain a payout of coins from the machine, said means for sensing
a physical shock comprising:
a piezoelectric sensor (1) for mounting to the machine for detection of a physical
shock thereto; and
signal provision means (2), having an input for receiving signals from the piezoelectric
sensor (1) and an output for providing signals to a control section of the machine
when a physical shock is detected.
2. Means for sensing a physical shock as claimed in Claim 1, wherein said piezoelectric
sensor (2) is a ceramic disc piezoelectric sensor.
3. Means for sensing a physical shock as claimed in Claim 1 or Claim 2, wherein said
signal provision means (2) comprises one or more amplifiers (12,13) and a switching
transistor (16), wherein there is provided at an output of the switching transistor
a logic signal indicative of a physical shock of above a predetermined magnitude threshold.
4. Means for sensing a physical shock as claimed in Claim 3, wherein the signal provision
means (2) further comprises a light emitting diode (14) between said amplifier or
amplifiers (12,13) and said switching transistor (16) to provide a visual indication
of presence of a signal sufficient to provide a logic signal indicative of a physical
shock to the control section of the machine.
5. An amusement machine comprising means for sensing a physical shock as claimed in any
preceding claim, said amusement machine further comprising a control section and means
controlled by the control section for diversion of coins to an internal cashbox when
a physical shock is detected.
6. An amusement machine as claimed in Claim 5, wherein said piezoelectric sensor is mounted
to the machine with adhesive tape.
7. An amusement machine as claimed in Claim 6, wherein said piezoelectric sensor is mounted
to the inside of the cashbox door.
8. An amusement machine as claimed in any of Claims 5 to 7, wherein the signal provision
means is provided on a printed circuit board mounted on pillars in the proximity of
the piezoelectric sensor.