Circuit for Monitoring the Sequence of Events at a Cashier Checkout Center

The present invention relates to monitoring circuits and, more specifically, to circuits for monitoring the sequence of events at a cashier checkout center.

At a commercial parking facility situations often arise wherein a customer approaches a cashier checkout center or booth, pays his fee and exits the lot, all without the cashier having entered the customer transaction on his cash register. These circumstances may arise, for example, where the facility charges a fixed parking fee, or where a customer knows his fee, fixed or hourly, in advance and has the exact change. Often, as during rush hours when traffic backs up at the checkout center, the cashier may be tempted to set aside the transaction, i.e., parking ticket and money, for later entry on the register when business slackens. It has previously been recognized that such an accumulation of a transaction backlog is undesirable. Stated differently, it has heretofore been recognized that the checkout center cashier should be encouraged to follow a preselected sequence during the checkout procedure which includes the step of entering into the register the transaction associated with a particular customer before accepting the parking ticket and money from the next customer.

In circuits heretofore proposed for monitoring the sequence of events at a cashier checkout center, an array of relays has been provided, with the relays being sequentially energized as customers approach the checkout center and de-energized when the associated transactions are registered, the number of relays energized at any given time being thereby indicative of the cashier's transaction backlog. However, a number of problems associated with circuits of this type have rendered them generally unsatisfactory. For example, sequencing problems often occur when a car approaches the checkout center at the same time as the cashier is attempting to enter the previous transaction, whereby the circuit becomes unsynchronized and is rendered useless until reset.

It is an object of the present invention to provide a circuit for monitoring the sequence of events at a cashier checkout center which is economical in assembly and reliable in operation, which may be selectively preprogrammed and/or reprogrammed to monitor for a transaction backlog of any selected number, and which will not become desynchronized in operation .

The novel features which are considered to be characteristic of the present invention are set forth in particular in the appended claims. The invention itself, however, together with additional objects, features and advantages thereof, will be best understood from the following description when read in conjunction with the accompanying drawing which is a schematic diagram of a presently preferred embodiment of the cashier monitor circuit provided by the present invention.

Referring to the drawing, the cashier monitor circuit 10 herein disclosed includes an electromechanical, bidirectional counter 12 having an add- or increment-coil 14 and a subtract- or decrement-coil 16. Increment-coil 14 is connected via counter terminal 18 through a normally open switch 20 at a cash register 22 to a positive D.C. voltage source 24. Switch 20 provides a momentary closure, on the order of one hundred fifty milliseconds in duration, when a customer transaction is entered into register 22. Similarly, decrement-coil 16 is connected via counter terminal 26 through a normally open switch 28 to voltage source 24 in a customer detector 30 which, in the case of parking lot cashier monitoring circuits, comprises a conventional magnetic detector responsive to the proximity of an automobile to close switch 28. Detector 30 preferably comprises a model LD-10-B magnetic proximity detector marketed by the assignee hereof. Switch 28 provides a momentary closure, again on the order of one hundred fifty milliseconds in duration, when an automobile first approaches the checkout center. Coils 14, 16 are also connected to signal ground 32 via counter terminals 34, 36 respectively. A pair of diodes 38, 40 are respectively connected in the reverse voltage direction across coils 14, 16 to suppress inductive ringing therein. A pair of normally open push botton switches 42, 44 for checking and preprogramming counter 12 are respectively connected between voltage source 24 and counter terminals 18, 26.

A relay coil K1 is connected from ground 32 to voltage source 24 through a second normally open switch 46 in detector 30. Switch 46 provides a steady closure for the duration of time that a customer, in this case in an automobile, is in the proximity of the checkout center. A diode 48 is connected in the reverse voltage direction across coil K1. A pair of normally open relay contacts K1-A operatively associated with coil K1 are respectively connected through a capacitor 50 to ground 32 and through a resistor 52 to voltage source 24. Similarly, a pair of normally closed relay contacts K1-B operatively associated with coil K1 are respectively connected to the voltage side of capacitor 50 and to a counter terminal 54. It will be recognized, of course, that contact pairs K1-A and K1-B may conveniently constitute a single relay contact set having a common contact connected to capacitor 50, a normally open contact connected to resistor 52 and a normally closed contact connected to terminal 54.

A normally open switch 56 is provided within counter 12 between terminal 54 and another counter terminal 58. In a presently preferred embodiment of the invention, switch 56 provides a closure between counter terminals 54, 58 when the count in counter 12 drops below zero, i.e., is decremented stepwise through zero. In one working model of the present invention wherein counter 12 comprises a four level, electromechanical decade counter manufactured by Sedco of Geneva, Switzerland, Model No. RR111E, switch 56 comprises a closure bar on the thousands wheel of the counter, which bar makes electrical contact with a pair of fixed terminals when the associated wheel is in the "nine" position. Thus, switch 56 closes when counter 12 is decremented from a count of zero to a count of 9999. Of course, switch 56 will reopen at a counter of 8999; however, as will become evident from the discussion to follow, this would represent a backlog of over one thousand transaction entires, a circumstance which is not foreseen in normal operation. Counter terminal 58 comprises the output from cashier monitor circuit 10 and may be connected to a suitable alarm or to a device for recording a cashier backlog violation.

In the operation of monitor circuit 10, counter 12 is first preprogrammed by entering a count equal to the number of transactions in an allowable backlog. For example, if a backlog of two transactions is to be allowed before a cashier violation is noted, a count of two is entered into counter 12 by depressing switch 42 twice. Should it later be decided that the number of transactions in an allowable backlog must be reduced to one, the counter may be reprogrammed by merely pushing switch 44 once, thereby decrementing the counter. It will be assumed in the following discussion that circuit 10 has been preprogrammed for an allowable backlog of one transaction. Operation of circuit 10 for an allowable backlog of two or more transactions will become evident. It will be understood, of course, that the number of transactions in an allowable backlog is usually set by the management of the associated premises and not by the cashier. Accordingly, switches 42, 44 may be located within a locked enclosure or at a management office remote from the checkout center. With cashier monitor circuit 10 programmed at the allowable transaction backlog, the associated checkout center or booth may be opened for business.

As the first customer approaches the checkout center, proximity switch 26 is momentarily closed, thereby decrementing counter 12 to a count of zero. At the same time, switch 46 closes, energizing relay coil K1 and charging capacitor 50 via contact K1-A and resistor 52. If the customer presents the exact amount of his parking fee, he may leave the checkout center before the cashier has had an opportunity to register the transaction. Accordingly, this transaction does not yet constitute a backlog. When the first customer leaves, coil K1 is de-energized and the voltage side of capacitor 50 is connected to counter terminal 54 via contacts K1-B.

A second customer may now approach the checkout center, providing a pulse at counter terminal 26 such that the counter is decremented to 9999 and switch 56 is closed. However, the second customer also reenergizes relay K1 via switch 46 so that capacitor 50 is no longer connected to terminal 54. If the cashier now enters either the first or second customer's transaction, the counter will be incremented to zero so that switch 56 re-opens and no violation signal will be noted when the second customer leaves. If, however, the second customer departs before the cashier has registered either the first or the second transaction, switch 56 remains closed such that, when relay coil K1 is deenergized, the voltage on capacitor 50 is presented at output terminal 58, thereby indicating that the allowable backlog of one has been exceeded, i.e., providing a violation signal. Additional customers passing through the checkout center will each initiate a violation signal until the backlog is reduced to an allowable level of one (or zero).

It will now be apparent that the cashier monitor circuit provided by the present invention and disclosed hereinabove fully satisfies all of the objects, aims and advantages previously set forth. Furthermore, it will be evident that, although the invention has been disclosed in connection with a specific embodiment thereof, many alternatives, modifications and variations will suggest themselves to persons skilled in the art in view of the foregoing description. For example, although the invention as disclosed comprises a specific type of electromechanical counter 12, suitable digital counting means having an appropriate "borrow" output may be readily substituted therefor where the application permits. Similarly, although the invention has been disclosed in connection with a parking lot cashier booth where it has been found to be particularly advantageous, the invention may be readily adapted to different types of cashier checkout centers where similar circumstances apply. Accordingly, the invention is intended to embrace these and all other such alternatives, modifications and variations as fall within the spirit and broad scope of the appended claims.