GB2500587A - A cash drawer used with a cash register having money detection means - Google Patents

Abstract

A system of the detection of human error during the operation of an electronic cash register uses the transaction data (payment amount, total cost, tendered amount) to generate a list of possible cash tokens (notes and coins) which would constitute a correct cash transaction. The list is narrowed by comparing each combination in the list with measurements taken from the cash drawer. The list is further narrowed by using likely user activity and patterns of behaviour, such that customers are unlikely to use large numbers of coins. The cash token movements for the transaction can then be verified. Alerts can be given to the cashier if the token movements cannot be verified according to the transaction data. The measurements may be weight data. A further embodiment comprises a mechanism to suspend cash tokens in a cash drawer on a cantilever or lever. The weight and the turning force can be measured by two force transducers positioned at the fulcrum point and the end of the cantilever or lever. Coin and note holders are pivoted at set points on the cantilever or lever meaning that the weight of the holders is applied at set points also.

Description

DESCRIPTION

DESCRIPTION OF DRAWINGS

FIGURE 1 -SYSTEM OVERVIEW Figure 1.1 -System Flow Diagram S The figure 1.1 diagram shows the general operation of the system for each retail transaction the invenlion is used in. When a transaction is entered into an electronic point of sale (EPOS) terminal the information is stored in a log file, which is then parsed into an algorithm to generate a list of all cash token combinations that's value equates to the value of the payment and the value of the refunded change, up to a pre-set maximum number of tokens per combination; at the same time a print receipt message is sent to a printer device, this triggers a solenoid in the cash drawer to fire releasing the lock mechanism inside allowing the operator access to the coins inside. The operator attempts to put the cash tokens in the correct compartments, removes the correct value in change, and then closes the cash drawer; after a short settle time a measurement is taken from the turning force transducer and the pivotal force transducer, is processed into a turning force and a weight value and sent to the computer to compare against the generated list of cash token combinations. Meanwhile after the cash drawer is closed, there is a short delay due to the operator tearing the receipt and begin to hand the cash to the customer. During this short delay several fast algorithms will run, reducing the list of token combinations down significantly; first the list is reduced based on the weight differential between the most recent measurement and the previous one, discarding combinations that could not produce the mass differential; next the list is processed against whether the combination could produce the measured turning force differential (calculated by the difference between the current and immediately previous turning force measurement), based on whether the tokens were placed at the expected or different compartments in the cash tray. Once the processing is finished, a probability is generated for any remaining combinations on the list; if there are no combinations left or if the probability is below a certain level then an alert is sent out to the operator, to double check the change taken out of the drawer. If the operator chooses to act on the alert, then the original combination list is then reprocessed with new force measurements once the operator adds and removes the necessary cash tokens and gives the corrected change to the customer. All this activity is stored on a local log file and then sent off to a storage server.

Figure 1.2 -Mechanic Lever diagram The figure 1.2 diagrams show how the lever mechanism works in order to measure both the turning force the cash tokens apply and the total weight of the cash tray and tokens. Essentially all the cash tokens are stored in compartments in a tray. In order for the weight of the contents of each compartment to be applied at a single point along the axis of the lever, the coin containers are pivoted allowing the centre of mass of the container to swing. Similarly the note containers are modified to allow only slight movements of the notes along the axis of the lever, thus reasonably assuring the cash notes applied weights are at set points along the lever.

Additionally the points, which the weights are applied, do not overlap; thus allowing weights to be distinguished from each other using an algorithm.

When the system is flattened into two dimensions (gravity and the length of the lever) you can see the effective turning force of each weight about the fulcrum point, which is held in equilibrium by the reactive force applied by the force detector. The system can also be seen to be held in equilibrium vertically, reactive forces countering gravity as there is no movement on that axis. These two states of equilibrium produce two equations, which can be used to calculate the weight of the cash tray and tokens and also be used to compute the weights applied at each of the distances.

Figure 1.3 -Cash Mass Distribution The figure 1.3 diagrams show the mass distributions of some Great British Pound [GBP) coinage. Due to damage through usage, age, dirt, and production variations, the masses range from the expected mass by a small amount The variations differ uniquely for each type of cash token, whether they are a coin or note; and these variations form a bell-curve when measured in bulk, which can be used to calculate the probability a cash token lies within a range of masses.

The diagrams shown were created from a data set of the masses of one thousand cash tokens taken from circulation.

FIGURE 2 -HARDWARE SCHEMA TICS Figure 2.1 -Preliminary Hardware Layout The figure 2.1 diagram shows a preliminary layout for the cash drawer invention's hardware.

The diagram is split into three sections showing the three components of the cash drawer: the cash register housing, the cash drawer, and the cash tray. The cash register housing section shows a fairly standard layout: a simple wheel and slider mechanism for the cash drawer, a spring loaded catch & locking mechanism, and a cable inlet/outlet block. The cash drawer section shows the standard drawer components a'ong with the invention specific modifications.

The components labelled 21 to 26 are the invention specific modifications, they consist of electronics for handling the force measurements and for managing communication with the a computer system; a lever mechanism (23) that is pivoted [24) against a load cell (25) and held in equilibrium against a load cell [22), and a mechanism [26] to allow for the cash tray to attach to the lever. The cash tray has been modified, such that the coin containers are pivoted at set distances that do not overlap with the centres of the note containers. The coin containers hang freely allowing the centre of mass of the containers and contents to move in line with the pivot point. The attachment (36) is designed to attach the cash tray rigidly to the lever mechanism in cash drawer.

Figure 2.2 -Lever Mechanism The diagram in figure 2.2 shows a preliminary design for the lever mechanism in the cash drawer. This element houses the two load cell systems to that measure the downward force on the pivot and the upward turning force of the lever. The lever mechanism is attached to the side of the cash drawer using the ridge on the side as an anchor. The pivot is raised so that the lever, when attached, would be roughly perpendicular to the force of gravity when resting against the housed load cell.

Figure 2.3 -Tray & Lever Connection The diagrams in figure 2.3 show a preliminary design for the lever design and the cash trays connector mechanism to mount on the lever. The lever diagram shows a right angle crank that has a large area attachment that connects with the cash tray so that the turning force is spread over that area.

Figure 2.4 -Tray & Container Mechanism The diagrams in figure 2.4 show a preliminary design for the pivoting coin compartments. The designs show a clip on the pivot axis on each of the coin compartments, which rests on two points on the pivots in the surrounding housing. The pivots are equally spaced along the lever axis and the distances are set such that the effective turning forces about the lever pivot do not align with each other to a reasonable degree.

FIGURE 3 -ELECTRONICS SCHEMA Ti Cs Figure 3.1 -Preliminary Block Diagram The diagram in figure 3.1 shows a preliminary block diagram for the electronics of the invention. There are at least two force transducers (in this case load cells are used) attached to separate AC/DC converters and input into the processor; multiple force transducers can be used in parallel attached to an AC/DC converter. The force transducers measure the turning force of the cash tray lever mechanism of the invention and the downward force applied on the pivot of the lever mechanism. Additional inputs for the processor include a push button switch for the detecting when the cash drawer is opened and closed; and a transistor mechanism to detect when the solenoid fires in the catch & lock mechanism. The processor manages all the input mechanisms and outputs it via a USB interface to a computer for further processing.

DESCRIPTION

The invention is an improvement to the standard cash register in an EPOS system that enables the system to keep track of physical cash entering and leaving the cash register. The improved cash register does this by taking several force measurements about the cash contents and from its general usage; performing some minor processing on these measurements and then sending them to the computer in the EPOS system for further processing and use in other systems.

The method of identifying cash being added and/or removed from the cash register uses the transaction information gathered from the EPOS software interface; namely the amount to be paid into the register and the amount to be refunded. This information is parsed into an algorithm to generate a list of cash tokens combinations that equate to those two values; in order to prevent this list and algorithm running for too long the number of tokens in any given combination is limited to a predefined number; i.e. it is fairly rare that more than ten cash tokens are ever used to pay or refund an amount of money in a retail transaction, therefore the use of generating combination that have more than ten cash tokens in are redundant. The crux of the invention is to then compare each item in this generated list against a simulation of the physical system with measured values gathered from the live hardware for that transaction; a probability is generated for each item in the list and a combined probability for the transactions likelihood of being correctly executed is calculated, which is stored and can be used in other systems. Figure 1.1 shows the invention being used to power with two such systems; those being a real-time loss prevention system that alerts the EPOS till operator to recheck the amount of money taken out of the register, and an information gathering system that can be used to evaluate a rating for an operators activity or to verify that the log keeping from the cash reconciliation is correct.

The hardware inside the modified cash register is designed in such a way that it suspends the cash holding tray as a lever, which is held in equilibrium against a force transducer while pivoted against another force transducer. This allow two forces to be measured from the cash contents; the total downward force of objects acting on the lever, and the total turning force caused by the cash tray and tokens on the ever from a set distance away. These measurements are processed to find the effect that a single retail transaction has had on the cash contents; and is done by taking the immediately previous measurements and subtracting them from the current ones. To turn these measurements into more meaningful values the weight of the cash tokens is calculated by subtracting the measured turning force from the downward force on the pivot measurement Figure 1.2 shows the general concepts behind this lever and measurement mechanism, along with the relevant equilibrium equations.

The cash tray is modified, such that the cash token content's masses are applied at set point along the axis of the lever. This is for the purpose of virtually remodelling the system with a much greater accuracy, based on the extracted measurements. The cash tray is modified in two ways to do this; the cash note compartments are shaped such that the cash notes are unable to move along the axis of the pivot to a significant degree. Due to the consistency in mass disLribulion Lhroughoul Lhe noLes volume Lhe cenLre of mass is kepL roughly in line wiLh Lhe centres of each compartment. The cash coin compartments are modified such that each individual coin compartment is pivoted on the axis of the ever, allowing the centre of mass to swing and rest in line with the pivot point; an example of this can be seen in figure 2.4. The positioning of the centres of the cash compartments have been spaced so that they do not line up with one another along the axis of the lever; the purpose of this is to more uniquely identify where a cash token has been placed, due to the compartments that are further away from the lever's pivot point causing more turning force than closer ones. The spacing has also been designed with the lever's pivot point and the distance to the (turning force measuring) force transducer in mind. The distances are set so that the turning forces caused by standard cash tokens from a single official currency do not overlap with one another; hence being able to identify the cash tokens uniqu&y from one another, not only on weight but also on the positions that they are placed within the cash tray.

The measurements are taken by the use of force transducers in certain locations in the design; an example of this would be the use of load cells as shown in the figure 3.1 and the positions in figure 1.2. In order to measure the forces accurately the load cells are attached to an alternating current, by measuring both peaks of the signal background noise is cancelled out giving a greater accuracy, hence the AC/DC converters. The signals are sent to a processor to convert them into values; and these are sent to a USE chip to convert the values into the correct format to communicate them to the computer. In addition to this the electronics also monitor general cash register activity, such as the firing of a solenoid in the catch/release mechanism and a push switch that detects when the cash drawer opens and closes; these signals are also sent to the processor to be communicated to the computer.

The values when received by the computer are date stamped and stored in a log file for backup and reference purposes. It is assumed at this point that the list of cash item combinations for both the payment and refund have been calculated, because the amount of time taken for the generation is substantially smaller than the user related activity for operating the cash register.

Firstly the weight change value is used to shortlist the list of every combination; this is done by comparing the two generated lists and finding the combinations that could produce the given weight change, this is stored in a separate list (aka the shortlist). The reason the weight change va'ue is done first is it is relatively less process intensive when compared to the simulation algorithm required to compare the turning force value; this is important due to the time limitation of the user gathering a receipt from the retail transaction and handing the change cash tokens to the customer. An example of the weight value being compared: Transaction: Payment: £5.00 Refund: £2.01 Current combination: Tokens added: £5 note (0.88gJ Tokens removed: £2 coin, lp coin [12g+3.56gJ Resultant mass change: -14.68g (Mm: -15.12g Max: -13.98gJ Measured mass change: -14.58g Possible Combination: Yes (Measured mass is within range) Each of the combinations in the shortlist is then simulated in an expected behaviour model; this is where the turning force is generated for each combination, assuming that all the tokens are placed in the correct compartments. It is important to do this stage as the algorithm to determine the turning forces assuming the tokens could have been placed in any compartment is an order of magnitude more complex and as it is an uncommon event tokens are placed in the wrong compartments it saves on processing time. The simulation involves the equations in figure 1.2; the known distances are used for each of the token types in each combination and the expected turning force is calculated about the pivot point. The turning force is then compared much like the previous mass comparison and a further short list is generated. If this further shortlist is empty of the probability of the shortlist is below a set level then a more complex simulation of the hardware is made, where each cash token in each combination is used in every possible compartment (coin compartments for the coins, and note compartments for the notes); this is also compared against the list of combinations like the previous comparisons. The finalized list is then processed for the probability of each combination and the total probability that the transaction has been operated successfully; the information is then stored in a log file to be used by further systems.

Due to damage through general use, dirt and grease through handling, and production defects the masses of cash tokens deviant around a mean mass. The masses when collected on large scales and displayed in a mass distribution graph, as shown in figure 1.3; result in bell curve style distributions. These distributions are unique for each type of cash token in every possible 205 currency. They can be used to generate a probability for cash tokens being of a certain mass, or in this implementation the probability of a group of cash tokens being of a certain mass. This is useful because increases the accuracy of detecting coin combinations that would contain extreme mass outliers. Due to the range of masses all the force measurements are affected by this, so it is important that the characteristics of the tokens are used when processing the lists of 210 cash token combinations.

As stated previously some of the systems that are able to take advantage of these results include: Real-time loss prevention systems to prevent mishandling of cash, data gathering systems, and a verification system for the cash reconciliation records.

The real-time loss prevention system takes advantage of the speed of the transaction 215 probability calculation in comparison to the time taken by the till operator to finalize the transaction. Once the probability has been generated it is assumed that the till operator has gathered the customer receipt and is about to hand over the money to the customer. At this point if the probability is below a certain level an alert is sent to the computer screen for the till operator to recheck the money. Alternatively a simple alert system can be used to el1 the till 220 operator to either wait before handing over the money, hand over the money, or a recheck money message. The till operator will either ignore the message or act on it; if it's acted on then the cash register will be opened and the cash will be changed; new measurements will be taken and communicated to computer, which wifl result in a new set of processing being done on the original generated list for the transaction. An alert will be shown if the transaction has again 225 been done incorrectly; it can either be ignored or acted on.

A data gathering system implementation is fairly simple in comparison, as the system stores information in its log files, whether they are the simple activity of the cash register, measurements taken, or the generated shortlist and probabilities; this information is forwarded to either an in-store temporary storage server to be sent to a centralized headquarters storage 230 server; orjusL lobe senL direcily Lo the headquarLers server. Furiher analysis Lechniques can be used on this centralized store of information, such as performance analysis on individual till operators, overall store performances, time taken per transaction, and a vast number of other ana'ytical techniques.

The data gathered by the system can also be used to verify the cash reconciliation stages at the 235 sthrt and end of the day. Based on the total measured values from all the cash registers, an algorithm can he used to verify whether the count of money is correct Alternatively depending on the procedures used in store, it can be determined easily if money cash gone missing from a register while it was stored in a cash safe overnight. This is an important system, because it removes amount of trust needed for management employees when counting and handling large 240 amount of money, to a certain extent In addition to taking the force measurements, the cash register has been modified to also record and report its general activity; such as electronic signals opening and closing the cash register and whether they fail, and the manually opening and closing of the cash register. The monitoring of these are important, because of the parallel in the field in which the invention is 245 in; specifically it brings attention to when the cash register has been accessed outside of a transaction, and can assist in the prevention of thefts.

The cash register looks and operates as a regular EPOS cash register; the additional modifications do not interfere with its operation. The layout of the device internals can be seen in figure 2.1. The only parts that are relevant to this invention are: The IISB cable outlet, the 250 lever mechanism and load cells located on the side of the cash drawer, the electronics for processing the load cells and managing the communication with the computer, the connection point on the cash tray to attach to the lever mechanism, the pivoted coin containers, and the modified cash note containers.

The USB cable outlet is located on the cable block attached to the base of the cash register, it is 255 simply designed to allow the USB communication caNe to escape the cash register housing securely.

The lever mechanism and had cells are located on the side of the cash drawer, and are roughly designed as shown in figure 2.2. The lever mechanism is lined up roughly with the centre of mass of the cash tray to prevent turning forces in the perpendicular direction that the lever does 260 not operate in. The lever mechanism comes in two parts, with three load cells installed for stability. The pivot rests on two load cells, which in turn rest on a platform that hooks up and over the lever for a load cell to be housed. The housed load cell is positioned such that the lever rests against it; hence the reactive force of the load cell causes the lever to be held in equilibrium. An attachment at the end of the lever is shaped so that the tray connector can 265 attach and be removed easily, while also giving a large area for supporting the turning forces and weight of the tray when loaded.

The electronics for processing the load cells and managing the communication with the computer is housed in the side of the cash drawer, towards the rear of the compartment. This is to keep it relatively protected while also keeping it close to the load cells for a more signal. A 270 USS cable is passed through the flooring of the drawer and connected to the 1158 cable outlet, with enough slack so that the drawer can open and close normally without the 1158 cable being in tension at any point.

The side of the cash tray has been modified with a connection point that rigidly attaches it on the end of the lever mechanism. It is a slot type connector that allows the tray to be connected 275 and removed easily from the drawer.

The pivoted coin containers are located in the cash tray lined up along the axis of the lever mechanism as shown in figure 2.1 and 2.4; also the modified cash note containers are shown.

Claims (9)

1. CLAIMS1] A system for the purpose of detecting human error in operation of an electronic cash register system that uses payment amount, total cost and/or refund transaction information to generate a list of possible cash tokens that would constitute a correct cash transaction; then reducing that list down by scrutinizing each combination against measurements taken from the mechanical system holding the cash tokens; and reducing the list using pre-knowledge of the likelihood user activity and patterns of behaviour.
2. 2] Claim 1 where the cash token combination list is reduced using the measured change in weight of the cash token contents between the opening and closing of the cash drawer, in order to verify each combination could produce that weight change and discarding those that cannot from the list.
3. 3] Claim 1 where the cash token combination list is reduced using pre-knowledge of the distances that cash tokens weights and force measurement devices are applied along the pivotal axis of a cantilever or lever mechanism, and a force change measured between the opening and closing of the cash drawer, at a fixed point along the pivotal axis of the cantilever or lever mechanism; in order to verify each combination could produce that force change, either by each token being placed in its correct compartment or by being placed in an incorrect compartment and discarding the combinations that cannot from the list.
4. 4] Claim 1 where the reduced list of cash token combinations is used to calculate a probability for the transaction being correct, or otherwise deemed suspicious or impossible; the probability is then used to alert the operator if the transaction is suspicious or impossible, and the information is stored to be used by other systems.
5. 5] A mechanism to suspend the plurality of cash tokens in a cash drawer on a cantilever or lever, whereby the weight and turning force can be measured by two force transducers positioned at the fulcrum point and at the end of the cantilever or lever respectively.
6. 6] Claim 5 where the plurality of cash tokens are stored in a modified cash tray; containing suspended coin holders pivoted at set points along the axis of the cantilever or lever, allowing their weight to be applied at a set points along that axis; containing note containers that allow only minute movements along the axis of the cantilever or lever, keeping the centre of mass of the contained cash note tokens applied at the central points along that axis in the container.
7. 7] Claim 5 where a force transducer is positioned at a fixed point along the axis of the cantilever or lever, such that the reactive force applied between the force transducer and cantilever or lever would hold the system in equilibrium; for the purpose of using the pre-knowledge of the distances between the force transducer and fulcrum point, and the distances between the fulcrum point and the applied weights of each of the cash token containers along the axis of the cantilever or lever, along with a measured signal produced by the force transducer to calculate or verify the possible cash tokens added and/or removed between two adjacent measurements.
8. 8) Claim S where a force transducer is positioned beneath the fulcrum point of the cantilever or lever, such that the reactive force between the cantilever or lever and the force transducer is held in equilibrium against the weight of the cash tray and the reactive force of the other force transducer against the cantilever or lever; for the purpose of calculating the weight of the cash tray by calculating the difference between the measured force from two force transducers; for the purpose of calculating or verify the possible cash tokens added and/or removed between two adjacent measurements of the force transducers.
9. 9) Any previous claim where cash tokens are assumed to have non-standardized masses due to damage and/or dirt through general usage, resulting in a probability mass distribution unique to each type of cash token; and are processed with the pre-knowledge of these mass distributions.