Shopping cart system

Abstract

To provide a shopping cart system capable of securing durability of a power supply device for supplying a charging current to a shopping cart.SOLUTION: The shopping cart system includes a shopping cart (hereinafter referred to as a cart) having a terminal for registering a commodity, and a power supply device for supplying a charging current to a battery of the terminal. The cart includes an input connector that receives a charging current and a DC voltage of a DC power supply different from a supply power supply of the charging current from the power supply device or a cart in a previous stage, a first resistor connected in series to an input line of the DC voltage, and a first output connector that outputs the DC voltage via the first resistor and a part of the charging current received by the input connector to an input connector of another cart connected to a subsequent stage of the cart. The power supply device includes a second output connector that outputs a charging current and a DC voltage via a second resistor connected in series to an output line of the DC power supply to the input connector of the cart, and an energization control unit that stops the charging current when a current flowing through the second resistor falls below a predetermined value.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a shopping cart system. [Background technology]

[0002] Conventionally, a shopping cart has been proposed that is equipped with a product registration device, allowing customers to register the products they want to purchase while shopping in a store. Such shopping carts are moved to a predetermined location and the battery that operates the product registration device is charged (for example, Patent Document 1).

[0003] In such shopping carts, multiple shopping carts can be stacked on top of each other and their batteries can be charged. To this end, each shopping cart is connected to the other via electrical contacts. Current is supplied from the power supply to the upstream contact, but as the number of connected shopping carts increases, the current supplied from the power supply may exceed the rated current. Continued use of the power supply with a current exceeding the rated current may impair the durability of the power supply. Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a shopping cart system that can ensure the durability of a power supply device that supplies charging current to the shopping cart. [Means for solving the problem]

[0005] A shopping cart system according to an embodiment includes multiple shopping carts each having a terminal device for registering products to be purchased, and a power supply device that supplies a charging current to the terminal device. Each shopping cart includes an input connector that receives, from the power supply device or a preceding shopping cart, a charging current for the terminal device's battery and a DC voltage from a DC power supply separate from the power supply that supplies the charging current, a first resistor connected in series to the DC voltage input line, and a first output connector that outputs the DC voltage via the first resistor and a portion of the charging current received by the input connector to an input connector of another shopping cart connected downstream of the shopping cart. The power supply device includes a second output connector that outputs, to the input connector of the shopping cart, the charging current and the DC voltage via a second resistor connected in series to the output line of the DC power supply, a current measurement unit that measures the current flowing through the second resistor, and an energization control unit that stops outputting the charging current when the current measured by the current measurement unit falls below a predetermined value. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is an external view illustrating an example of a shopping cart system according to an embodiment. [Figure 2] FIG. 2 is a first perspective view of a shopping cart. [Figure 3] FIG. 3 is a second perspective view of the shopping cart. [Figure 4] FIG. 4 is a perspective view showing an example of a power supply device. [Figure 5] FIG. 5 is a hardware block diagram illustrating an example of a hardware configuration of a shopping cart system according to an embodiment. [Figure 6] FIG. 6 is a first diagram showing an example of the configuration of the main parts of the power supply device and the output connector provided in the shopping cart. [Figure 7] FIG. 7 is a second diagram illustrating an example of the configuration of the main part of the output connector. [Figure 8] FIG. 8 is a first diagram showing the configuration of the main part of an input connector provided in a shopping cart. [Figure 9]FIG. 9 is a second diagram illustrating an example of the configuration of the main part of the input connector. [Figure 10] FIG. 10 is a block diagram illustrating an example of a functional configuration of the energization control circuit included in the shopping cart system according to the embodiment. [Figure 11] FIG. 11 is a diagram illustrating a method for the shopping cart system to estimate the number of connected shopping carts. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments described below.

[0008] A shopping cart 10 according to an embodiment of the present disclosure will now be described with reference to the drawings.

[0009] (Shopping cart system overview) A schematic configuration of a shopping cart system 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is an external view showing an example of a shopping cart system according to an embodiment.

[0010] The shopping cart system 1 includes a power supply device 50 and a plurality of shopping carts 10.

[0011] The power supply device 50 supplies a current to the shopping cart 10 connected to it for charging the battery 29 that drives the cart terminal 20 provided in the shopping cart 10. The power supply device 50 is, for example, an AC adapter or an AC / DC converter. The power supply device 50 converts a commercial AC voltage of 100V into a predetermined DC voltage Ea (for example, +24V) and supplies it to the shopping cart 10 connected to it.

[0012] The battery 29 of the shopping cart 10 is charged by current supplied from the power supply device 50. Specifically, the output connector 53 (see FIG. 4) of the power supply device 50 is connected to the input connector 31 (see FIG. 3) of the shopping cart 10, thereby supplying the current for charging to the shopping cart 10. When multiple shopping carts 10 are stacked as shown in FIG. 1, the output connector 34 (see FIG. 2) of the preceding shopping cart 10, which is closer to the power supply device 50, is connected to the input connector 31 (see FIG. 3) of the succeeding shopping cart 10, thereby supplying the current for charging to the succeeding shopping cart 10. In terms of the electrical circuit, the batteries 29 of each shopping cart 10 are connected in parallel from the perspective of the power supply device 50. The structures of the input connector 31 and the output connectors 53 and 34 will be described in detail below (see FIGS. 6 to 9).

[0013] The number of connectable shopping carts 10 is determined, for example, by the current value that the power supply device 50 can output, the charging current of the battery 29, the current consumption of the cart terminal 20, and the current consumption of various connected devices. For example, if the rated current that the power supply device 50 can output is 10A and the charging current required to charge the battery 29 is 1A, excluding the current consumption of wiring, etc., the number of shopping carts 10 that can be charged simultaneously is 10. However, if the batteries 29 of some of the 10 connected shopping carts 10 have already been fully charged, charging current will not be supplied to the shopping carts 10 that have fully charged, so the 11th and subsequent shopping carts 10 can also be charged. In other words, the upper limit of the number of shopping carts 10 that can be currently being charged among the shopping carts 10 connected to the power supply device 50 is 10.

[0014] Generally, power supply devices 50, and more specifically, AC adapters and AC / DC converters provided in power supply devices 50, are capable of outputting currents exceeding their rated current. For example, a power supply device with a rated current of 10 A can output a maximum current of approximately 12 A. However, because continued use above the rated current may impair the durability of the power supply device 50, it is desirable to use it within a range below the rated current. For this reason, in the shopping cart system 1 of this embodiment, the power supply device 50 has a function to stop supplying charging current when more than a predetermined number of shopping carts 10 are stacked. This will be described in more detail below (see FIG. 10).

[0015] (Shopping cart outline) The general configuration of the shopping cart 10 will be described with reference to Figures 2 and 3. Figure 2 is a first perspective view of the shopping cart, and Figure 3 is a second perspective view of the shopping cart.

[0016] As a customer walks through a store pushing the shopping cart 10, it reads product information about the products the customer wants to purchase and registers those products. The customer places the registered products in a shopping basket or the like placed on the shopping cart 10 and continues shopping. After finishing shopping, the customer goes to a cash register (not shown) and has the cash register process the payment for the registered products. The shopping cart 10 itself may be equipped with a function to process the payment.

[0017] For convenience, an XYZ coordinate system including an X-axis, a Y-axis, and a Z-axis is defined in this specification. The XYZ coordinate system is established for the shopping cart 10. The X-axis, Y-axis, and Z-axis are perpendicular to one another. The X-axis is established along the front-to-rear direction of the shopping cart 10. The Y-axis is established along the width direction (left-to-right direction) of the shopping cart 10. The Z-axis is established along the height direction (up-down direction) of the shopping cart 10.

[0018] Furthermore, in this specification, the X direction, Y direction, and Z direction are defined. The X direction is a direction along the X axis, and includes the +X direction indicated by the X axis arrow and the -X direction opposite the X axis arrow. The Y direction is a direction along the Y axis, and includes the +Y direction indicated by the Y axis arrow and the -Y direction opposite the Y axis arrow. The Z direction is a direction along the Z axis, and includes the +Z direction indicated by the Z axis arrow and the -Z direction opposite the Z axis arrow. Furthermore, the +Z direction is the same as the upward vertical direction, and the -Z direction is the same as the downward vertical direction.

[0019] The shopping cart 10 includes a frame 60, a pair of front wheels 70 (see FIG. 3), and a pair of rear wheels 71. The frame 60 includes a pair of left and right bottom frames 61, a lower frame 62, and an upper frame 63. The pair of left and right bottom frames 61, the lower frame 62, and the upper frame 63 are connected to one another. The distance between the pair of front wheels 70 is narrower than the distance between the pair of rear wheels 71. The front wheels 70 and the rear wheels 71 are installed spaced apart in the fore-and-aft direction (X direction) of the shopping cart 10. The front wheels 70 and the rear wheels 71 are attached to the bottom frame 61 by mounting members (not shown). The front wheels 70 and the rear wheels 71 can turn left and right around their attachment positions on the bottom frame 61. Therefore, the direction of travel of the shopping cart 10 can be changed left and right depending on the force applied to a handle 72 installed above the shopping cart 10. In other words, the shopping cart 10 is rotatable. The customer holds the handle 72 and pushes the shopping cart 10 while turning it from side to side.

[0020] A charging unit 30 is attached between the pair of left and right bottom frames 61. The charging unit 30 has a built-in charging circuit 32 (see FIG. 5), which charges the battery 29. The charging unit 30 also has an input connector 31 (see FIG. 3) and an output connector 34. The charging unit 30 also serves as a strength member connecting the left and right bottom frames 61.

[0021] The input connector 31 is a charging connector that connects to the output connector 53 (see FIG. 4 ) of the power supply device 50. The input connector 31 receives a current from the power supply device 50 for charging the battery 29 that powers the cart terminal 20. The input connector 31 also receives a DC voltage signal from the power supply device 50 for determining the number of connected shopping carts 10. The input connector 31 also includes a ground line that transmits a ground (GND) level, which is a reference potential, from the power supply device 50. That is, the input connector 31 transmits three types of signals. The input connector 31 also serves as a charging connector that connects to the output connector 34 of the preceding shopping cart 10. The input connector 31 receives a current from the output connector 34 of the preceding shopping cart 10 for charging its own battery 29. The input connector 31 also receives a DC voltage signal from the output connector 34 of the preceding shopping cart 10 for determining the number of shopping carts 10 connected to the power supply device 50. Furthermore, the input connector 31 includes a ground line that transmits a ground (GND) level, which is a reference potential, from the output connector 34 of the preceding shopping cart 10. The input connector 31 is attached to the housing 38 of the charging unit 30 with its exterior covered by an input connector cover 311. The input connector 31, the output connector 34, and the output connector 53 of the power supply device 50 are all installed at the same height from the floor. The detailed structure of the input connector 31 will be described in detail later (see Figures 8 and 9).

[0022] The output connector 34 is a charging connector that connects to the input connector 31 of the subsequent shopping cart 10. The output connector 34 transfers a portion of the current supplied to the preceding shopping cart 10 for charging the battery 29 to the subsequent shopping cart 10. The output connector 34 also supplies a DC voltage signal, supplied from the preceding shopping cart 10, to the subsequent shopping cart 10 for determining the number of shopping carts 10 connected to the power supply device 50. The output connector 34 also includes a ground line that transmits a ground (GND) level, which is a reference potential, from the preceding shopping cart 10. The output connector 34 is attached to the housing 38 of the charging unit 30 with its exterior covered by an output connector cover 341. The detailed structure of the output connector 34 will be described in detail later (see FIGS. 6 and 7). The output connector 34 is an example of a first output connector in this disclosure.

[0023] A lower frame 62 is attached to the front side (+X direction) of the bottom frame 61, rising upward (+Z direction) and then extending diagonally upward toward the front (-X direction). The lower frame 62 holds the battery 29. The battery 29 is a rechargeable secondary battery that supplies current to various electronic devices equipped in the shopping cart 10. The battery 29 may be, for example, a lithium-ion battery, a nickel-cadmium battery, a nickel-metal hydride battery, or a lead-acid battery.

[0024] The battery 29 is equipped with an indicator 35. The indicator 35 is composed of a light-emitting element such as an LED, and indicates the charging status of the battery 29 by the charging circuit 32 (see FIG. 5). The indicator 35, for example, can be in an off state, a lit state, a flashing state, or the like, to indicate, for example, that the battery 29 is fully charged, that the battery 29 is charging, or that charging has stopped. The indicator 35 may be composed of multiple LEDs, and each state may be indicated by the number of LEDs that are lit or the combination of the LEDs that are lit. The indicator 35 may also be composed of multiple LEDs that emit different colors, and each state may be indicated by the different colors of the LEDs that are lit.

[0025] A pair of upper frames 63 are attached to the upper ends of the lower frames 62, facing upward (in the +Z direction). A rod-shaped handle 72 is attached to the pair of upper frames 63, extending along the left-right direction (Y direction) of the shopping cart 10. Various electronic devices provided on the shopping cart 10 are attached to the upper frames 63 and the handle 72.

[0026] A lower basket support frame 64 is attached to the bottom frame 61 and the lower frame 62. A shopping basket (not shown) is placed on the lower basket support frame 64 to hold items when a customer goes shopping. The lower basket support frame 64 also has a pair of left and right guide surfaces 641. When a subsequent shopping cart 10 enters between them, the pair of guide surfaces 641 come into contact with a guided portion 621 provided below the lower frame 62 of the subsequent shopping cart 10, thereby guiding (leading) the subsequent shopping cart 10 so that the input connector 31 of the subsequent shopping cart 10 faces its own output connector 34.

[0027] An upper basket support frame 65 is attached to the upper frame 63. A shopping basket (not shown) is placed on the upper basket support frame 65 to accommodate merchandise when a customer goes shopping.

[0028] Additionally, a weight sensor 28 is installed on the upper frame 63 at a position extending toward the front (-X direction). The weight sensor 28 is located below the upper basket support frame 65 and measures the weight of an item placed in a shopping basket placed on the upper basket support frame 65.

[0029] The cart terminal 20, hand scanner 25, card reader 26, and camera 27 (see FIG. 3) are mounted on the upper part of the upper frame 63. In addition, the fixed scanner 24 is mounted on the handle 72. These electronic devices are powered by the battery 29.

[0030] The cart terminal 20 registers products to be purchased by customers. The cart terminal 20 includes a display unit 22 and an operation unit 23. The cart terminal 20 may further include a function for making payments for registered products. The cart terminal 20 is an example of a terminal device in the present disclosure.

[0031] The display unit 22 displays various information related to product registration. The display unit 22 is, for example, a liquid crystal monitor or an organic EL monitor.

[0032] The operation unit 23 detects operations on various buttons displayed on the display unit 22. The operation unit 23 is, for example, a touch panel laminated on the display unit 22.

[0033] The fixed scanner 24 reads a code symbol, such as a barcode, attached to a product for sale that is held up to a reading window on the front. A product code that uniquely identifies the product is registered in the code symbol. The fixed scanner 24 obtains the product code by decoding the code symbol reading result.

[0034] The hand scanner 25, like the fixed scanner 24, reads the code symbol attached to the product to obtain the product code. In particular, the hand scanner 25 is used to read the code symbol of a product that is difficult to read with the fixed scanner 24, such as a heavy or large product.

[0035] Card reader 26 reads information registered on an IC card or magnetic card held by a customer. Card reader 26 may read information stored on an electronic chip of an inserted IC card, or may read information stored on a magnetic stripe by scanning the card. Card reader 26 may also read information stored on the card by performing short-range wireless communication.

[0036] The card reader 26 reads, for example, membership information registered on the customer's membership card. The cart terminal 20 may display, on the display unit 22, bargain information on products that suit the customer's preferences, service information, etc., based on the membership information read by the card reader 26, for example, by referencing the customer's purchase history. If the shopping cart 10 also has a payment processing function, the card reader 26 may also read the registration information of the credit card used by the customer for payment, the charge amount of an electronic money card, prepaid card, etc.

[0037] The camera 27 captures an image of the area including the shopping basket placed on the upper basket support frame 65. The cart terminal 20 associates identification information for identifying itself, the image captured by the camera 27, the weight of the shopping basket measured by the weight sensor 28, and the product registration information at that time, and transmits the associated information to a store server (not shown).

[0038] The store server analyzes the information sent from the shopping cart 10 and monitors whether an unregistered item has been added to the shopping cart. Specifically, if the weight of the shopping cart increases even though an item has not been registered, it determines that the customer may have added an unregistered item to the shopping cart. In such a case, the store server sends a signal to the cart terminal 20 to alert the customer. The cart terminal 20 then displays a message on the display unit 22 to alert the customer. The cart terminal 20 may also output a warning sound from a speaker (not shown). Furthermore, the store server may notify a mobile device carried by a store clerk of the identification number of the corresponding shopping cart 10. The clerk, upon receiving the notification, goes to the corresponding shopping cart 10 and checks the product registration information and the items added to the shopping cart. Note that such monitoring processing may be performed by the cart terminal 20 itself.

[0039] Although Figures 2 and 3 only show the camera 27 and weight sensor 28 that monitor the shopping basket placed on the upper basket support frame 65, the camera and weight sensor may also be installed on the lower basket support frame 64, thereby enabling the configuration to monitor the shopping basket placed on the lower basket support frame 64 as well.

[0040] (Outline of power supply configuration) The general configuration of the power supply device 50 will be described with reference to Fig. 4. Fig. 4 is a perspective view showing an example of a power supply device.

[0041] The power supply device 50 includes a housing 501, an output connector 53, an output connector cover 531, and a guide portion 57. The power supply device 50 is installed (fixed) on, for example, a floor surface 100 of a store (see FIG. 1).

[0042] Housing 501 is formed in a rectangular parallelepiped shape. Inside housing 501, there are housed power transmission circuit 51, current control circuit 52, DC power supply 54, current measurement circuit 55, and indicator 56, all of which are shown in Fig. 5. The functions of each part will be described in detail later.

[0043] The guide portions 57 are a pair of protrusions provided along the Y axis with the output connector 53 sandwiched between them. The pair of guide portions 57 are installed at a distance slightly greater than the width of the guided portion 621 (see FIG. 3) of the shopping cart 10. The guided portion 621 of the shopping cart 10 is guided between the pair of guide portions 57, thereby facilitating connection between the input connector 31 of the shopping cart 10 and the output connector 53 of the power supply device 50.

[0044] (Hardware configuration of shopping cart system) The hardware configuration of the shopping cart system 1 will be described with reference to Fig. 5. Fig. 5 is a hardware block diagram showing an example of the hardware configuration of the shopping cart system of the embodiment.

[0045] The power supply device 50 provided in the shopping cart system 1 houses a power transmission circuit 51, a current control circuit 52, an output connector 53, a DC power supply 54, a current measurement circuit 55, and an indicator 56 inside a housing 501.

[0046] The power transmission circuit 51 is a power source that supplies a current required to charge the battery 29. The power transmission circuit 51 is composed of, for example, an inverter circuit that converts a commercial AC voltage of 100 V into a DC voltage, and a rectifier circuit that rectifies the output of the inverter circuit and converts it into a DC voltage Ea (for example, +24 V).

[0047] When a shopping cart 10 is connected to output connector 53 and the number of connected shopping carts 10 is less than a predetermined value, energization control circuit 52 supplies a charging current to the shopping cart 10 connected to output connector 53. Furthermore, energization control circuit 52 stops supplying the charging current when the number of connected shopping carts 10 is equal to or greater than the predetermined value. The function of energization control circuit 52 will be described in detail later (see FIG. 10).

[0048] Output connector 53 has the same size and shape as output connector 34 (see FIG. 2) provided on shopping cart 10. Output connector 53 is attached to housing 501 of power supply device 50 with its exterior covered by output connector cover 531. The detailed structure of output connector 53 will be described in detail later (see FIGS. 6 and 7). Output connector 53 is an example of a second output connector in the present disclosure.

[0049] DC power supply 54 is a voltage source that supplies DC voltage Eb (e.g., +5V) for determining the number of shopping carts 10 connected to power supply device 50. DC power supply 54 is generated, for example, by dividing DC voltage Ea generated by power transmission circuit 51.

[0050] The current measurement circuit 55 is a circuit that measures the voltage across a resistor r (see FIG. 10) that is connected in series to the output line of the DC voltage Eb. The operation of the current measurement circuit 55 will be described in detail later (see FIG. 10). The current measurement circuit 55 is an example of a current measurement unit in the present disclosure. The resistor r is an example of a second resistor in the present disclosure.

[0051] The indicator 56 is configured with a light-emitting member such as an LED, and lights up when the energization control circuit 52 is supplying a charging current, and goes out when the energization control circuit 52 is not supplying a charging current. The indicator 56 is an example of a notification unit in the present disclosure.

[0052] The shopping cart 10 included in the shopping cart system 1 includes a cart terminal 20, a charging unit 30, a battery 29, an indicator 35, and peripheral devices such as a fixed scanner 24, a hand scanner 25, a card reader 26, a camera 27, and a weight sensor 28.

[0053] The cart terminal 20 performs various processes related to product registration. The cart terminal 20 includes a control unit 21, a display unit 22, and an operation unit .

[0054] The control unit 21 controls various processes related to product registration performed by the cart terminal 20 itself. The control unit 21 also controls the operation of various peripheral devices connected to the control unit 21. The control unit 21 includes a CPU, RAM, ROM, and a storage unit. The CPU loads a control program stored in the storage unit into the RAM and executes it, causing the cart terminal 20 to perform predetermined processes related to product registration, etc. The functions of the display unit 22 and operation unit 23 provided in the cart terminal 20 are as described above.

[0055] The functions of the fixed scanner 24, hand scanner 25, card reader 26, camera 27, and weight sensor 28, which are peripheral devices connected to the control unit 21, are as described above. The functions of the battery 29 and indicator 35 are as described above.

[0056] The charging unit 30 charges the battery 29. The charging unit 30 includes an input connector 31, a charging circuit 32, an energization control circuit 33, and an output connector 34. A resistor R is connected in series to a signal line between the input connector 31 and the output connector 34, to which a DC power source 54 is supplied. The function of the resistor R will be described in detail later (see FIGS. 10 and 11). A switching element 80 (e.g., a MOSFET) that controls conduction / non-conduction by the output from the energization control circuit 33 is connected to the signal line to which the resistor R is connected. The function of the switching element 80 will be described in detail later.

[0057] The charging unit 30 is housed in a housing 38 (see FIGS. 2 and 3) and fixed to a frame 60. The input connector 31 and the output connector 34 are supported by the housing 38 and are exposed to the outside of the housing 38.

[0058] The input connector 31 inputs a current (voltage signal) from the power supply device 50 by connecting to the output connector 53 of the power supply device 50. The input connector 31 also inputs an electrical signal from the preceding shopping cart 10 by connecting to the output connector 34 of the charging unit 30 of the preceding shopping cart 10. The electrical signal is transmitted through three signal lines: a signal line that supplies the charging current, a signal line that supplies a voltage for determining the number of connected shopping carts 10, and a ground line that transmits the ground (GND) level. In other words, the input connector 31 has three terminals. In this embodiment, the input connector 31 is configured as a plug.

[0059] The output connector 34 outputs an electrical signal to the subsequent shopping cart 10 by connecting to the input connector 31 provided on the charging unit 30 of the subsequent shopping cart 10. Three signal lines are connected to the output connector 34: a signal line that supplies a charging current, a signal line that supplies a voltage for determining the number of connected shopping carts 10, and a ground line that transmits the ground (GND) level. In this embodiment, the output connector 34 is configured as a socket.

[0060] The charging circuit 32 supplies a portion of the current from the power supply device 50 to the battery 29 that powers the cart terminal 20 for charging.

[0061] The current control circuit 33 supplies current to the shopping cart 10 in the subsequent stage only when a shopping cart 10 is connected in the subsequent stage to itself. On the other hand, when no shopping cart 10 is connected in the subsequent stage to itself, the current control circuit 33 does not output current from the output connector 34. This prevents electric shock even if someone accidentally touches the output connector 34.

[0062] Furthermore, when no shopping cart 10 is connected downstream of the energization control circuit 33, the energization control circuit 33 outputs a control signal that turns on the switching element 80. Furthermore, when a shopping cart 10 is connected downstream of the energization control circuit 33, the energization control circuit 33 outputs a control signal that turns off the switching element 80. The control signal will be described in detail later (see FIG. 10).

[0063] (Output connector structure) The structures of output connector 53 and output connector 34 will be explained using Figures 6 and 7. Figure 6 is a diagram showing the main configuration of the output connectors provided on the power supply device and shopping cart. Figure 7 is a perspective view showing the detailed structure of the output connectors provided on the power supply device and shopping cart. Note that the output connector 53 provided on power supply device 50 and the output connector 34 provided on shopping cart 10 have the same structure, so here, the output connector 53 provided on power supply device 50 will be explained as an example.

[0064] The output connector 53 is installed facing the −X direction in the housing 501 (see FIG. 4) of the power supply device 50. The output connector 53 includes a socket 41, a socket 42, a socket 43, and a socket housing 44.

[0065] The socket 43 is formed of a conductive material and outputs a DC voltage Ea (for example, +24 V) from the power supply device 50. The socket 43 is also called a female terminal.

[0066] The socket 42 is formed of a conductive material and outputs a DC voltage from a DC power supply 54 via a current measurement circuit 55. The socket 42 is also called a female terminal.

[0067] The socket 41 is formed of a conductive material and is a ground (GND) terminal of the power supply device 50. The socket 41 is also called a female terminal.

[0068] Socket housing 44 is molded to surround the outer peripheries of sockets 41, 42, and 43, and supports sockets 41, 42, and 43 in parallel at a predetermined interval. That is, socket housing 44 has an outer periphery surface 441 that surrounds the outer peripheries of sockets 41, 42, and 43. Socket housing 44 is also referred to as a shell. Note that the arrangement of sockets 41, 42, and 43 is not limited to the example shown in FIGS. 6 and 7.

[0069] A switch 45 is embedded in the base of the outer peripheral surface 441 of the socket housing 44. The switch 45 includes a switch housing 451 and a switch button 452.

[0070] The switch housing 451 protects the internal structure of the switch 45 and supports the switch button 452 .

[0071] The switch button 452 is supported by a spring or other elastic member relative to the switch housing 451 so as to be reciprocatable along the extension direction (+X direction, −X direction) of the sockets 41, 42, and 43. When the input connector 31 is inserted into the output connector 53, the switch button 452 is pressed in the +X direction by a tip portion 314 (see FIG. 9 ) of a plug housing 49 of the input connector 31, which will be described later. The switch 45 performs a momentary operation, being turned on when the switch button 452 is pressed a predetermined amount and turned off when the amount of pressing is less than the predetermined amount. The current control circuit 52 of the power supply device 50 outputs a voltage signal from the output connector 53 when the switch 45 is on, and stops outputting the voltage signal when the switch 45 is off. In other words, the switch 45 functions as a so-called interlock switch.

[0072] An output connector cover 531 is attached to the outside of the socket housing 44. The output connector cover 531 has an opening 532 that exposes the outer peripheral surface 441 of the socket housing 44 to the outside. The opening 532 is sized so that even if a finger is inserted from the outside, the finger will not reach the switch button 452. This prevents the switch button 452 from being accidentally touched and causing a voltage signal to be output from the output connector 53.

[0073] In this embodiment, the switch 45 is configured as a push switch, but the form of the switch 45 is not limited to this. For example, the switch 45 may be configured as a photosensor configured as a pair of a light-emitting element and a light-receiving element. The switch 45 may also be configured as a magnetic sensor or a capacitive sensor.

[0074] The structure of the output connector 34 provided on the shopping cart 10 is the same as that of the output connector 53. That is, the output connector 34 is installed on the shopping cart 10 with the outer circumferential surface 441 of the socket housing 44 exposed to the outside through an opening 342 formed in the output connector cover 341. Then, the switch 45 provided on the output connector 34 causes the output connector 34 to output a voltage signal to the input connector 31 of the subsequent shopping cart 10 when the input connector 31 of the subsequent shopping cart 10 is connected.

[0075] (Input connector structure) The structure of the input connector 31 provided in the shopping cart 10 will be described using Figures 8 and 9. Figure 8 is a first diagram showing the configuration of the main parts of the input connector provided in the shopping cart. Figure 9 is a second diagram showing an example of the configuration of the main parts of the input connector.

[0076] The input connector 31 is installed on the positive side of the X-axis of the charging unit 30, i.e., on the front side of the shopping cart 10, facing forward with respect to the shopping cart 10. The input connector 31 includes a plug 46, a plug 47, a plug 48, and a plug housing 49.

[0077] The plug 48 is made of a conductive material and is removably connected to the socket 43. The plug 48 receives a voltage signal (e.g., +24 V) from the socket 43. The plug 48 is also referred to as a male terminal. A portion of the voltage signal received by the plug 48 is supplied to the battery 29 from the charging unit 30 in which the plug 48 is installed.

[0078] The plug 47 is formed of a conductive material and is removably connected to the socket 42. The plug 47 receives a DC voltage from the DC power supply 54. The plug 47 is also called a male terminal.

[0079] The plug 46 is formed of a conductive material and is removably connected to the socket 41. The plug 46 equalizes its own potential with the potential (ground potential) of the socket 41. The plug 46 is also called a male terminal. The arrangement of the plugs 46, 47, and 48 is not limited to the examples shown in FIGS. 8 and 9. That is, the plugs 46, 47, and 48 are arranged so as to be removably connected in the combinations described above in accordance with the arrangement of the sockets 41, 42, and 43 provided in the output connector 53 (34).

[0080] The plug housing 49 is formed to surround the plugs 46, 47, and 48 with gaps between it and the plugs 46, 47, and 48, and supports the plugs 46, 47, and 48 in parallel at the same intervals as the sockets 41, 42, and 43. The plug housing 49 has an elongated cylindrical inner circumferential surface 313, and the depth of the inner circumferential surface 313 is greater than the length of the plugs 46, 47, and 48, and a tip portion 314 is formed at the tip of the inner circumferential surface 313.

[0081] The plug housing 49 is fixed to the charging unit 30 by screwing or the like.

[0082] An input connector cover 311 is attached to the outside of the plug housing 49. The input connector cover 311 has an opening 312 through which the plugs 46, 47, and 48 and the plug housing 49 that protects them pass.

[0083] When connecting the input connector 31 to the output connector 53 or the output connector 34, the inner surface 313 of the plug housing 49 is inserted along the outer surface 441 of the socket housing 44, thereby connecting the plug 46 and the socket 41, connecting the plug 47 and the socket 42, and connecting the plug 48 and the socket 43.

[0084] In this embodiment, the input connector 31 is configured to include plugs 46, 47, and 48, and the output connectors 34 and 53 are configured to include sockets 41, 42, and 43, but this is not limiting. For example, the input connector 31 may be configured as a pogo pin, and the output connectors 34 and 53 may be configured as flat terminals.

[0085] In addition, in this embodiment, a configuration has been described in which three types of signals are transmitted between the input connector 31 and the output connectors 34 and 53, but a configuration in which only a signal that accepts DC voltage from the DC power supply 54 is transmitted through a separate connector may also be used.

[0086] (Functional configuration of the power supply control circuit in the shopping cart system) The functional configuration of the energization control circuits 52 and 33 included in the shopping cart system 1 will be described with reference to Fig. 10. Fig. 10 is a block diagram showing an example of the functional configuration of the energization control circuit included in the shopping cart system of the embodiment.

[0087] The power supply device 50 includes a power supply control circuit 52 that includes a contact determination unit 521 and a power supply control unit 522.

[0088] The contact determination unit 521 detects whether the sockets 41, 42, 43 and the plugs 46, 47, 48 are in contact with each other, i.e., whether the shopping cart 10 is connected to the power supply device 50. The contact determination unit 521 is configured, for example, by a circuit that is conductive when the switch 45 is turned on, or a circuit that outputs a predetermined voltage when the switch 45 is turned on. The specific circuit configuration is not important. The contact determination unit 521 may also be configured by a circuit that is non-conductive when the switch 45 is turned off.

[0089] The energization control unit 522 is configured with a switching circuit that, when triggered by the output of the contact determination unit 521, causes the DC voltage Ea to be output from the socket 43 to the downstream shopping cart 10. The energization control unit 522 is, for example, a load switch. The specific circuit configuration of the switching circuit is not important, but it may be, for example, a switching circuit using a MOSFET, or a mechanical or electrical relay.

[0090] Furthermore, when a current i (see FIG. 11) measured by a current measurement circuit 55, which will be described later, falls below a predetermined value, the energization control unit 522 stops the supply of the DC voltage Ea, that is, the charging current.

[0091] The power supply device 50 further includes a current measurement circuit 55. The current measurement circuit 55 measures a current i (see FIG. 11) that flows through a resistor r built in therein.

[0092] A resistor R having the same resistance value is connected in series to the signal line supplying the DC voltage Eb to each shopping cart 10. Resistor R is an example of a first resistor in the present disclosure. Therefore, the current i flowing through resistor r has a value corresponding to the number of shopping carts 10 connected to the power supply device 50. In other words, the shopping cart system 1 can predict the number of shopping carts 10 connected to the power supply device 50 based on the value of current i. A method for predicting the number of shopping carts 10 connected to the power supply device 50 will be described in detail below (see FIG. 11).

[0093] An indicator 56 is also connected to the power supply control circuit 52. The indicator 56 lights up when a charging current is being supplied and goes out when the supply of the charging current is stopped. When the indicator 56 is out, the store manager may, for example, reduce the number of shopping carts 10 connected to the power supply device 50.

[0094] The charging unit 30 provided in the shopping cart 10 includes a current control circuit 33. The current control circuit 33 includes a contact determination unit 521 and a current control unit 523.

[0095] The contact determination unit 521 detects whether another shopping cart 10 is connected to the rear of the shopping cart 10. The contact determination unit 521 has the same configuration as the contact determination unit 521 included in the power supply device 50.

[0096] The energization control unit 523 is configured with a switching circuit that, triggered by the output of the contact determination unit 521, outputs the DC voltage Ea received from the power supply device 50 or the preceding shopping cart 10 to the subsequent shopping cart 10 from the socket 43. The energization control unit 523 has the same configuration as the energization control unit 522 provided in the power supply device 50, but does not have the function of stopping the supply of charging current based on the voltage measured by the current measurement circuit 55 provided in the energization control unit 522.

[0097] Furthermore, when the shopping cart 10 is not connected downstream of the energization control unit 523, the energization control unit 523 outputs a control signal to turn on the switching element 80 (described later). Furthermore, when the shopping cart 10 is connected downstream of the energization control circuit 33, the energization control circuit 33 outputs a control signal to turn off the switching element 80.

[0098] As described above, the charging unit 30 provided in the shopping cart 10 has a resistor R connected in series between the plug 47 supplied with the DC voltage Eb and the socket 42. The resistance value of resistor R is assumed to be the same for all charging units 30 (shopping carts 10). The current measurement circuit 55 described above measures a current corresponding to the number of shopping carts 10 connected to the power supply device 50, thereby predicting the number of shopping carts 10 connected to the power supply device 50. A specific prediction method will be described later (see FIG. 11).

[0099] A switching element 80 is connected between the signal line to which DC voltage Eb is supplied and the ground line. The switching element 80 is turned on or off in response to a control signal from an energization control unit 523. The switching element 80 is, for example, a MOSFET, but is not limited to this as long as it has a similar function. In FIG. 10, the switching element 80 is a MOSFET, and the control signal from the energization control unit 523 is input to the gate of the MOSFET via an inverting amplifier 81. That is, in the configuration of FIG. 10, when another shopping cart 10 is connected downstream of the shopping cart 10, the energization control unit 523 outputs a high-level signal. The high-level signal is inverted by the inverting amplifier 81, rendering the switching element 80 non-conductive. When the switching element 80 is non-conductive, a DC voltage from the DC power supply 54 (see FIG. 5) is output from the output connector 34 to the input connector 31 of the downstream shopping cart 10. On the other hand, when another shopping cart 10 is not connected downstream of the shopping cart 10, the energization control unit 523 outputs a low-level signal. The low-level signal is inverted by the inverting amplifier 81, causing the switching element 80 to conduct. When the switching element 80 conducts, the DC voltage from the DC power supply 54 drops to ground via the switching element 80. The inverting amplifier 81 is configured by, for example, an operational amplifier.

[0100] (Method for estimating the number of connected shopping carts) A method for the shopping cart system 1 of the embodiment to estimate the number of shopping carts 10 connected to the power supply device 50 will be described with reference to Fig. 11. Fig. 11 is a diagram illustrating a method for the shopping cart system to estimate the number of connected shopping carts.

[0101] FIG. 11 shows an equivalent circuit of a circuit to which DC voltage Eb is supplied from DC power supply 54 (see FIG. 5) of power supply device 50 when n shopping carts 10 are connected to power supply device 50. As shown in FIG.

[0102] The DC voltage Eb supplied from the DC power supply 54 is transmitted via a resistor r provided in the current measurement circuit 55 and resistors R, all of which have the same resistance value, provided in the charging units 30 of each shopping cart 10. At this time, the switching element 80 provided in each shopping cart 10 is non-conductive when a shopping cart 10 is connected to the subsequent stage, and is conductive when no shopping cart 10 is connected to the subsequent stage. Therefore, when n shopping carts 10 are connected to the power supply device 50, the DC voltage Eb supplied from the DC power supply 54 is applied to a circuit in which resistor r and n resistors R are connected in series. A current i corresponding to the number of connected shopping carts 10 flows across resistor r.

[0103] Resistor r is connected in series to the circuit that outputs DC voltage Eb, and resistor R is connected in series to the circuit that outputs DC voltage Eb, so the current i that flows through resistor r when n shopping carts 10 are connected to power supply device 50 is calculated by equation (1). For convenience, the resistance value of resistor r is defined as r, and the resistance value of resistor R is defined as R.

[0104] i=Eb / (r+nR)…(1)

[0105] For example, assuming Eb=5V and r=R=100Ω, when one shopping cart 10 is connected to the power supply device 50, i=25mA. When two shopping carts 10 are connected to the power supply device 50, i=16.7mA. When three shopping carts 10 are connected to the power supply device 50, i=12.5mA.

[0106] In this way, as the number of connected shopping carts 10 increases, the current i measured by the current measurement circuit 55 decreases. When 10 shopping carts 10 are connected to the power supply device 50, the current i becomes 4.5 mA.

[0107] When the current i flowing through the resistor r falls below 4.5 mA, the current control circuit 52 (see FIG. 10) determines that more than 10 shopping carts 10 are connected, and stops the supply of charging current from the power supply device 50.

[0108] In this embodiment, all shopping carts 10 are connected to resistors R with the same resistance value. However, there are cases where shopping carts 10 with different charging currents are connected to the power supply device 50. Even in such cases, the shopping cart system 1 of this embodiment can estimate the number of connected shopping carts 10. For example, if it is assumed that a shopping cart 10 with a charging current of 1 ampere is connected to a resistor R with a resistance value of 100 Ω, and a shopping cart 10 with a charging current of 2 amperes is connected to a resistor R with a resistance value of 200 Ω, the number of connected shopping carts 10 can be estimated even when a mixture of connected shopping carts 10 exists.

[0109] (Effects of the embodiment) As described above, the shopping cart system 1 of the embodiment includes multiple shopping carts 10 each having cart terminals 20 (terminal devices) for registering products to be purchased, and a power supply device 50 for supplying charging current to the cart terminals 20. Each shopping cart 10 includes an input connector 31 for receiving charging current for the battery 29 of the cart terminal 20 from the power supply device 50 or a preceding shopping cart 10, and a DC voltage from a DC power supply 54 provided in the power supply device 50 that is separate from the power supply supplying the charging current, a resistor R (first resistor) directly connected to the DC voltage input line, and an output connector 34 (first output connector) for outputting the DC voltage via resistor R and a portion of the charging current received by the input connector 31 to the input connector 31 of another shopping cart 10 connected downstream of the shopping cart 10. Power supply device 50 includes output connector 53 (second output connector) that outputs a charging current and a DC voltage via resistor r (second resistor) connected in series to the output line of DC power supply 54 to input connector 31 of shopping cart 10, current measurement circuit 55 (current measurement unit) that measures current i flowing through resistor r, and current control unit 522 that stops output of the charging current when the current measured by current measurement circuit 55 falls below a predetermined value. Therefore, power supply device 50 that supplies a charging current to shopping cart 10 can be used within the rated current range, thereby ensuring the durability of power supply device 50.

[0110] In the shopping cart system 1 of the embodiment, the power supply device 50 further includes an indicator 56 (notification unit) that notifies that the current supply control unit 522 has stopped the charging current. Therefore, it is possible to easily notify that the number of connected shopping carts 10 exceeds the specified number.

[0111] Furthermore, in the shopping cart system 1 of the embodiment, output connector 34 (first output connector) and output connector 53 (second output connector) are further provided with contact determination unit 521 that detects whether they and input connector 31 are in a predetermined contact state, and output connector 34 and output connector 53 allow current to flow to input connector 31 on the condition that contact determination unit 521 determines that the predetermined contact state exists, and prohibit current from flowing to input connector 31 on the condition that contact determination unit 521 does not determine that the predetermined contact state exists. Therefore, with a simple structure, a so-called interlock function can be realized that prevents electric shock even if an electric contact is touched with a hand.

[0112] Although the embodiments of the present invention have been described above, these embodiments are merely examples and are not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0113] 1. Shopping Cart System 10 Shopping Cart 100 floor 20 Cart terminal (terminal device) 21 Control Unit 22 Display section 23 Control section 24 Fixed Scanner 25 Hand Scanner 26 Card Reader 27 Camera 28 Weight Sensor 29 Battery 30 Charging Unit 31 Input Connector 311 Input connector cover 312 Opening 313 Inner surface 314 Tip 32 Charging circuit 33 Power control circuit 34 Output connector (first output connector) 341 Output connector cover 342 Opening 35 indicators 38 Case 41, 42, 43 Socket 44 Socket Housing 441 Outer surface 45 Switch 451 switch housing 452 Switch Button 46, 47, 48 Plug 49 Plug housing 50 Power supply 501 Case 51 Power transmission circuit 52 Power supply control circuit 521 Contact determination section 522,523 Power supply control unit 53 Output connector (second output connector) 531 Output connector cover 532 Opening 54 DC power supply 55 Current measurement circuit (current measurement section) 56 Indicator (alarm unit) 57 Information Department 60 frames 61 Bottom frame 62 Lower frame 621 Guided part 63 Upper Frame 64 Lower cage support frame 641 Guideway 65 Upper basket support frame 70 front wheel 71 rear wheel 72 Handle 80 Switching element 81 Inverting amplifier Ea, Eb DC voltage i current R resistance (1st resistance) r resistance (second resistance) [Prior art documents] [Patent documents]

[0114] [Patent Document 1] Japanese Patent Application Publication No. 2023-102931

Claims

1. A shopping cart system comprising a plurality of shopping carts each having a terminal device for registering products to be purchased, and a power supply device for supplying a charging current to the terminal device, Each of said shopping carts comprises: an input connector for receiving, from the power supply device or a shopping cart at a previous stage, a charging current for the battery of the terminal device and a DC voltage of a DC power supply provided in the power supply device, which is separate from a power supply that supplies the charging current; a first resistor connected in series to the DC voltage input line; a first output connector that outputs the DC voltage via the first resistor and a portion of the charging current received by the input connector to an input connector of another shopping cart connected downstream of the shopping cart, The power supply device a second output connector for outputting the charging current and a DC voltage via a second resistor connected in series with an output line of the DC power supply to the input connector of the shopping cart; a current measuring unit that measures a current flowing through the second resistor; and a current control unit that stops output of the charging current when the current measured by the current measurement unit is below a predetermined value. Shopping cart system.

2. The power supply device The charging device further includes a notification unit that notifies the user that the current supply control unit has stopped outputting the charging current.

10. The shopping cart system of claim 1.

3. The first output connector and the second output connector further include a contact determination unit that detects whether the first output connector and the second output connector are in a predetermined contact state with the input connector, The first output connector and the second output connector are configured to energize the input connector on condition that the contact determination unit determines that a predetermined contact state exists, and to prohibit energization of the input connector on condition that the contact determination unit does not determine that a predetermined contact state exists.

3. The shopping cart system according to claim 1 or 2.

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