Stackable chassis for a shopping cart

Abstract

Stackable chassis (2; 2') for a shopping cart (100), comprising at least a forward-tapering chassis frame (20) with two side rails (21) and with rollers (29) attached thereto, and a vertical frame (40) with at least two side rails (41), wherein the chassis (2) is stackable with further chassis (2; 2') with a stacking dimension S as a distance with respect to a longitudinal axis L of the chassis (2), characterized in that - that both side rails each have at least one at least single-pole external electrical contact unit (31) on their respective outer side and at least one at least single-pole internal electrical contact unit (32; 32'; 34; 34') on their respective inner side; or that at least one of the side rails (21) of the chassis frame (20) has at least one multi-pole external electrical contact unit on its outside and at least one multi-pole internal electrical contact unit on its inside and - that the at least one external contact unit (31) and the at least one internal contact unit (32; 32'; 34; 34') are arranged at a distance from each other corresponding to the stacking dimension S with respect to the longitudinal axis L on the chassis frame (20).

Description

[0001] The invention relates to a stackable chassis for a shopping trolley having the features of the preamble of claim 1.

[0002] There have been significant advances in the field of shopping carts in recent years, particularly in the development of so-called smart shopping carts. These modern shopping carts are often equipped with various technological components, such as displays, handheld scanners, and weight measurement systems, designed to make the shopping process easier and more efficient for customers. However, these technologies require a continuous power supply to function properly. Currently, it is common for the batteries of the electronics unit of such smart shopping carts to require charging. This is usually done by manually connecting and disconnecting a cable, which is not only time-consuming but also carries the risk of damage to the cables or charging ports.

[0003] Existing systems for powering smart shopping carts typically involve manual charging, requiring the carts to be brought to a charging station. This approach is not only labor-intensive but can also lead to disruptions in operations if the carts need to be charged during store hours. There is also a risk that carts will not be charged in a timely manner, which can lead to limited availability of smart features. Despite significant advances in smart shopping carts, there remains a need for more efficient and reliable power solutions that minimize manual effort and maximize uptime.

[0004] It is therefore a technical problem underlying the present invention to provide an improved solution for powering smart shopping carts that enables charging without having to establish manual cable connections.

[0005] This object is achieved by a stackable chassis for a shopping cart having the features of claim 1.

[0006] The stackable chassis for a shopping trolley typically comprises a chassis frame tapering towards the front, to which rollers are attached, with two side rails and a vertical frame with at least two side rails and at least one cross bar.

[0007] Both side members of the chassis frame are each equipped with at least one external electrical contact unit on the outside and at least one internal electrical contact unit on the inside. This arrangement of the electrical contact units enables an efficient and reliable electrical connection between stacked chassis that are positioned close together. Therefore, only narrow gaps need to be bridged with this arrangement.

[0008] The outer contact units and inner contact units are arranged at a distance from each other that essentially corresponds to the stacking dimension, ensuring that the contact units automatically make contact and establish an electrical connection when multiple trolleys are stacked. This configuration offers several advantages, including the ability to transmit not only electrical power but also data signals between stacked trolleys without the need for additional cabling or other manual connections. This is particularly useful for applications where the shopping carts mounted on the trolleys are equipped with electronic devices for goods detection, such as at least one scanner or at least one camera coupled with artificial intelligence.

[0009] The integration of the contact units into the side members of the chassis frame contributes to the robustness and durability of the system, as the contact units are protected by the stable structure of the chassis and are less susceptible to damage from external influences. Furthermore, handling of the chassis is simplified, as the electrical connection is established automatically as soon as the chassis are stacked, increasing operational efficiency and reducing the need for manual intervention.

[0010] Overall, the invention offers an innovative solution for integrating electrical systems into shopping carts that meets the demands of modern retail environments, where technological integration and adaptability are becoming increasingly important. This solution supports the development of smart shopping carts equipped with advanced features to enhance the shopping experience while increasing the efficiency of retail operations.

[0011] The contact points to be formed between adjacent chassis are divided into two or more contacts, whereby one contact is always the voltage transmitter leading to the adjacent chassis and one contact is the voltage receiver of the respective chassis.

[0012] It is essential that the distance between an external contact unit and an internal contact unit is selected such that the electrical connection is established at the distance between two chassis when they are pushed together. This distance is predetermined by the geometry of the chassis frame and / or by fixed attachment points on the chassis and is therefore always the same in a stack of identical chassis. This distance, referred to as the stacking dimension, serves in the invention as the basis for calculating the distance between the respective pairs of contact units forming the voltage transmitter and voltage receiver. Additions and deductions can be included in this dimension in order to enable reliable contact even if, for example, a chassis springs back slightly from a fixed attachment point on the front chassis when pushed together and the distance therefore increases slightly.

[0013] The following configurations are generally possible: - One of the side rails, i.e., the left or right, contains an inner contact unit and an outer contact unit. This provides an electrical line through the entire stack, isolated from the chassis, and also establishes a ground connection between chassis in the stack via the metal chassis frames. - Both side rails, the left and right, each contain an inner contact unit and an outer contact unit. This allows two separate electrical wiring paths to be created within the stack without the need for a weather-prone ground connection between the metallic surfaces of the chassis. - The same advantage as in No. 2 is achieved by having one of the side rails with multi-pole contact units, through which two or more separate electrical lines can be established at the same time. - It is also conceivable to provide several pairs, each with an inner contact unit and an outer contact unit, on at least one of the side rails, by arranging these pairs offset one behind the other along the length of the side rail. This can either create a redundant connection that increases safety, or at least create an additional line that can be used, for example, for data transmission.

[0014] Multi-pole contact units are preferably designed to have two or more contact surfaces arranged vertically one above the other. This arrangement enables a reliable and stable electrical connection between the chassis when the chassis are pushed together, with a separate connection being established in the plane of each contact. The vertical arrangement of the contact surfaces with horizontal extension ensures that separate electrical connections can be made at a single transition point. The vertical arrangement of the contact surfaces, one above the other, can also facilitate maintenance and cleaning of the contacts, as dirt and moisture are wiped off when pushed together and therefore do not impair function.Another advantage of this arrangement is the ability to integrate multiple electrical contacts into a compact design that doesn't compromise the overall aesthetics and functionality of the trolley. The two- or multi-pole contact units also offer the flexibility to support various electrical functions, such as power transmission for electronic devices or communication between trolleys. These features help ensure that the trolley serves not only as a mechanical support but also as an integral part of a modern, connected shopping experience.

[0015] It is also possible for the two-pole contact units to each have at least two contact surfaces arranged horizontally one behind the other.

[0016] According to a further embodiment, the chassis of a shopping trolley comprises a specific arrangement of electrical contact units on the side members of the chassis frame, in which in each pair one contact unit has at least one rigid contact element and the other contact unit has at least one resilient or resiliently mounted contact element.

[0017] The advantage of this arrangement lies in the improved electrical connection and contact stability between the stacked trolleys. The combination of rigid and spring-loaded contact elements ensures a reliable electrical connection, even when the trolleys are stacked in different positions or at slightly varying angles to each other. The spring-loaded contact element can adapt to surface irregularities and tolerances and bridges the increasing distance between adjacent side rails when one trolley moves slightly backwards relative to the other, thus ensuring a constant and secure connection. The combination of rigid and spring-loaded contact elements offers a robust solution to the challenges of electrical connection in a dynamic and often harsh operating environment, such as shopping carts.

[0018] According to one embodiment of the trolley chassis described in the invention, the outer contact units are equipped with rigid contact elements, while the inner contact units have resilient contact elements. The rigid contact elements of the outer contact units are shock-resistant. On the other hand, the resilient contact elements of the inner contact units provide a flexible and adaptable connection. These spring mechanisms allow the inner contact units to adapt to different contact points, which is particularly useful when connecting the trolley chassis to other components or modules within the shopping cart. The resilient design ensures that a stable electrical connection is maintained despite minor deviations in the alignment or position of the contact points.This dual contact design, which combines rigid and spring elements, enables increased reliability and flexibility in the operation of the chassis. Another advantage of this arrangement is the potential reduction of wear and mechanical stress on the contacts, as the spring elements can absorb movement and vibration that could otherwise lead to contact damage. These properties help extend the service life of the contact units and minimize maintenance requirements. Furthermore, the combination of rigid and spring contacts can improve the efficiency of energy transfer by ensuring that the contacts are always optimally aligned, thus minimizing electrical resistance.These features are particularly beneficial in an environment where shopping carts are frequently stacked and moved, as they ensure consistent performance and reliability regardless of the physical conditions the chassis is exposed to.

[0019] Preferably, the external contact units serving as voltage receivers are equipped with a fixed contact element and are located further forward in the travel or longitudinal direction than the internal contact units serving as voltage transmitters, which have a spring-loaded contact element and are positioned further back. This protects the spring-loaded contact elements from impact during normal use of the chassis, i.e., outside the stack.

[0020] However, a reverse arrangement is also possible.

[0021] In order to ensure that the contact elements of adjacent chassis meet securely during so-called stacking, i.e. when the chassis are pushed into one another, and to form a reliable electrical contact, a preferred embodiment provides, in addition to the spring elements, for at least one of the contact elements to be made longer than the other or for both to be made so long and to be arranged in such a way that an overlapping area is formed in the stack.

[0022] This position must be set so that the trolleys are in permanent contact when they are in the parked position, even if someone pulls the shopping trolley out slightly or it bounces back slightly. This means that the trolley trolleys do not have to be pushed exactly into one another and they can still have electrical contact with each other. To this end, it is particularly intended that the distance measured in the direction of the longitudinal axis L between the contact units corresponds to the stacking dimension S. This distance refers to the distance between a contact point of the contact element in the inner contact unit, for example the tip of the spring-loaded contact element, and the center of the contact element in the outer contact unit. In addition, the length of the contact element of the outer contact unit corresponds to at least 5% of the stacking dimension.This specific arrangement and dimensioning of the contact elements enables a precise and reliable electrical connection between the trolleys when they are stacked. The precise positioning of the elements relative to each other ensures that the contact elements of the inner and outer contact units are in the correct position relative to each other for optimal electrical conductivity. The length of the contact element of the outer contact unit, which is at least 5% of the stack dimension, ensures that there is sufficient contact surface to enable a stable electrical connection. These features contribute to the robust and reliable electrical connections between the stacked trolleys, which is particularly important when using electrical systems in shopping carts.An advantage of this arrangement is increased safety, as precise positioning and sufficient contact area minimize the risk of electrical misconnections or short circuits.

[0023] The contact elements are made of an electrically conductive material such as brass or copper.

[0024] All contact elements are preferably mounted on an electrically insulating support element, e.g., made of plastic, especially when, as is usually the case, the chassis frame is made of metal profiles. The use of electrically insulating support elements prevents short circuits and ensures safe and reliable electrical insulation of the contact elements. This design allows the electrical contact units to remain functional even after repeated use and under various environmental conditions. A further advantage of this arrangement is the easy maintenance and replaceability of the contact elements, as they are mounted modularly on the support elements. This facilitates maintenance and extends the service life of the chassis.

[0025] According to a further embodiment, the chassis comprises support elements, each of which has protective bars below and above the contact elements, extending in the longitudinal direction of the side rails. These protective bars physically protect the contact elements against impacts, thus increasing their functionality and durability. The protective bars also serve as a barrier against external influences such as dirt or moisture that could impair the electrical contacts. Placing the protective bars above and below the contact elements ensures that the contact elements are located in a protected space, reducing the likelihood of short circuits or corrosion. This is particularly advantageous in environments where the shopping carts are regularly used outdoors and are therefore exposed to various weather conditions.The protective bars also contribute to the structural integrity of the chassis by increasing the stability of the support elements, thus ensuring the secure connection of the electrical contacts. The protective bars are designed not to impair the functionality of the electrical contacts, but rather to increase their efficiency by protecting them from external influences. They prevent the contact elements from being damaged during stacking. This is especially important to ensure the longevity and reliability of the electrical connection between stacked chassis.

[0026] According to a further embodiment, the contact units are designed such that their support elements are inserted into recesses in the inner and / or outer side surfaces of the side members of the chassis frame, and only the actual contact elements are flush with or protrude above the side surfaces of the side members. Cable connections to and from the contact units can be routed within the hollow profiles that typically form the chassis. Furthermore, the flush placement of the support elements in the recesses barely alters the outer contour of the chassis, which facilitates stacking the chassis.

[0027] In a contact unit with at least one resilient contact element, versions are preferably provided in which the resilient contact element is designed as a spring pressure contact or as a spring sheet contact

[0028] A spring-loaded contact features a contact element, such as a bolt, that can be moved within the support element against the force of a spring. This bolt is slidably guided in a guide and features positive locking devices to hold it within the guide against the spring force and / or to prevent it from being pushed too far into the guide.

[0029] According to a further embodiment of the invention, at least one resilient contact element is provided, which is formed by a spring plate. This spring plate is designed to have a specific contour that allows elastic deformation transverse to the longitudinal extent of the side member. This deformation leads to an elongation of the spring plate, which ensures improved adaptability and flexibility in the electrical contact between the components of the chassis. The elastic deformability of the spring plate maintains a constant contact force, ensuring a stable electrical connection, even with slight movements or vibrations that may occur during use.

[0030] The chassis can be equipped with the usual goods receptacles to form a complete shopping cart, i.e. in particular with a basket on top and / or a base shelf underneath. The goods receptacles are preferably stored on the chassis via load cells. To be stackable, the shopping cart not only has a chassis that tapers towards the front, but also an upper, forward-tapering basket with a pivoting rear flap. If a lower shelf is also present, it is enclosed by a shelf frame that is articulated to the chassis and whose rear end can be raised when stacking several identical shopping carts.

[0031] According to the invention, it is possible to push several shopping trolleys into each other and at the same time to establish at least a two-pole electrical contact between the chassis in the stack, so that the batteries of all shopping trolleys in the stack can be charged simultaneously.

[0032] When used shopping carts equipped with the inventive trolleys are returned to the row, they automatically center themselves by sliding into one another and establish electrical contacts. This allows charging not only during store closing hours, but also continuously during operation, as long as a shopping cart is parked in the stack.

[0033] The invention also relates to a parking and charging station for a stack of chassis.

[0034] In the parking and charging station, a row start element is provided, into which the first shopping cart with a chassis according to the invention is pushed to form the start of a loading chain. The row start element has at least one row start contact unit, which is compatible in terms of shape and position with the at least one external contact unit on the chassis. If the chassis has a multi-pole external contact unit, the row start contact unit is also multi-pole. If the chassis is provided with one external contact unit on each side according to one of the preferred embodiments described above, two row start contact units are provided accordingly. The row start contact units are preferably provided with resilient contact elements.

[0035] The parking and charging station preferably comprises a housing having a power connection for the AC electrical network and a power supply unit whose output poles are connected to the series start contact units.

[0036] Furthermore, the chassis themselves can each have an electronic unit that enables charge level monitoring, connection monitoring, and, if necessary, data communication between adjacent chassis in the stack. This allows various charging modes to be set: - If the electronics unit of a chassis in the stack detects that no current is flowing from the front section of the stack to the external contact unit serving as a current collector, it carries out a charge level check of its own energy storage device. - If the charge level is above a first threshold, the electronics unit can establish a connection between the energy storage unit and its own internal contact unit, allowing batteries from chassis further back in the stack to be charged. A further connection can also be established to its own external contact unit, allowing a battery from a chassis at the front of the stack that is also cut off from the parking and charging station to be charged. If the charge level drops below a second threshold, these connections are interrupted. - If the own state of charge is already below the first threshold value when the connection to the start of the series element is interrupted, a connection can also be established between the own battery and the own internal contact unit, which is only permeable in one direction, in order to charge the own battery via the battery of at least one chassis at the back of the stack.

[0037] The advantage is that a group of chassis isolated from the rest of the stack forms a parallel connection of several batteries, between which balancing charges are easily possible.

[0038] It is also possible for the chassis to communicate with each other through digital data exchange via one or more of the contact units in order to coordinate with each other and / or with the parking and charging station using software. For this purpose, data signals can be modulated onto the power supply lines located in the stack between the chassis.

[0039] Another possibility is to network the electronics unit with other components of the same shopping cart or other shopping carts by also using the electrical contact units on the side members of the chassis frame for data transmission.

[0040] This networking can also provide wireless communication and data transmission between various electronic components of the shopping carts and a higher-level central unit. The electronic unit can, for example, be connected to a central supermarket system to provide real-time information or to track the shopping cart. This offers the user an improved shopping experience and the supermarket an opportunity to better manage its shopping cart fleet.

[0041] The invention is described below with reference to the exemplary embodiments illustrated in the drawings. The figures show in detail: Fig. 1 an embodiment of a stackable chassis for a shopping cart in a perspective view obliquely from above; Fig. 2 two chassis stacked one inside the other in perspective view from below; Fig. 3 the chassis from above; Fig. 4 two chassis stacked inside each other from above; Fig. 5 a shopping cart mounted on the chassis in a perspective view obliquely from above; Fig. 6 shows a first embodiment of an internal contact unit with a resilient contact element in a perspective view; Fig. 7 shows a second embodiment of an internal contact unit with a resilient contact element in a perspective view; Fig. 8 shows a third embodiment of an internal contact unit with a resilient contact element in a perspective view; Fig. 9 shows a fourth embodiment of an internal contact unit with a resilient contact element in a perspective view; Fig. 10 a front side of an external contact unit in perspective view; Fig. 11 a rear side of an external contact unit in perspective view; Fig. 12 a part of a side member of a chassis with an external contact unit and an internal contact unit from above; Fig. 13, Fig. 14 a section of two stacked chassis in different positions relative to each other, each from above and Fig. 15 the chassis with a loading device, in perspective view from above.

[0042] Fig. 1 shows a stackable chassis 2 for a shopping cart. The chassis 2 comprises a chassis frame 20 and a vertical frame 40. The chassis frame 20 consists of two side members 21, which are aligned in a forwardly tapered arrangement. They complement each other via a front section 22 to form a continuous, bow-shaped chassis frame 20 and are also supported against each other by a cross member 24. A bracket 23 is mounted between the front section 22 and the cross member 24, on which a load cell and / or a distribution box and / or an electronics unit can be mounted.

[0043] The chassis 2 is equipped with four pendulum-mounted rollers 29. The side members 21 are provided with several electrical contact units, including an external contact unit 31 and an internal contact unit 32, wherein the contact units 31, 32 are arranged at a distance from each other corresponding to the stacking dimension S.

[0044] The vertical frame 40 consists of two side members 41 and several crossbars 42, 43, 44, 45, the top of which serves as a push bar. An electronics unit 50 for communication with a user is attached to the crossbar 43.

[0045] The side rails 21 of the chassis frame 20 are equipped with various electrical contact units. The outer contact unit 31 is located on the outside of the side rails 21, while the inner contact unit 32 is attached to the inside of the side rails 21. These contact units are positioned so that they can come into contact with each other when stacking multiple chassis to establish an electrical connection.

[0046] Fig. Figure 2 shows two stacked bogies 2 in a perspective view from below. The front section of the bogie frame 20 of the rear bogie 2 rests against buffers on the cross member 24, which determines the distance between stacked bogies 2. The contact units 31, 32 are barely noticeable due to their integration into the side members 21. The figure illustrates that the electrical contact units 31, 32 are attached to both the outer and inner sides of the side members 21 to form electrical connections between the stacked bogies 2.

[0047] Fig. 3 shows the chassis 2 from above. Buffers 26 on the cross member 24 dampen the impact of a shopping cart pushed in from behind in the stack. The outer contact units 31 are arranged at the same position relative to the longitudinal axis L. The two inner contact units 32, 34 are arranged at a distance S from this. In this example, the inner contact units 32, 34 are different. The inner contact unit 32 has an elongated spring plate contact and, due to its length, has the advantage of being able to compensate for a tolerance in the distance between two shopping carts relative to the longitudinal axis. The left inner contact unit 34 has a spring pressure element, i.e. the bolt-shaped contact element is mounted in a support element against the force of a spring element such as a spiral compression spring and can be moved transversely to the longitudinal extent of the support element.Due to the length of the bolt pushed out of the side member 21 by means of the spring, a larger lateral distance between the side members 21 of two adjacent chassis can be bridged.

[0048] In Fig. Figure 4 shows the combination of two bogies 2 from above. The bogies 2 are pushed together as close as possible. The front section 2 of the rear bogie 2 rests against the buffers 26 on the cross member 24 of the front bogie 2. This results in the stacking dimension S. In this position, the external contact units 31 of the rear bogie 2 rest against the internal contact units 32, 34 of the front bogie 2, forming an electrical line from one bogie 2 to the other.

[0049] Fig. Figure 5 shows a complete shopping cart 100 with a chassis 2 and an upper basket 10 that tapers towards the front and has a pivoting rear wall flap 11. The basket 10 is connected via spacer brackets 12 to brackets 13, beneath which load cells are located. The part of the shopping cart used to hold goods, the so-called goods-holding unit, also includes a lower storage surface 14, wherein the storage surface 14 is enclosed by a storage frame 16 that is pivotally mounted on the chassis 2 and whose rear end can be raised when several identical shopping carts 100 are stacked. The goods-holding unit is connected to the chassis 2 only via two load cells, each located in the rear area on the side members 21, and via a third load cell, which is positioned concealed behind the front section 22 of the chassis frame in the illustration.

[0050] The electronics unit 50 and a hand scanner 51 are mounted on the vertical frame 40, which includes the side bars 41, the push bar 42 and further cross bars 43, 44.

[0051] Fig. 6 an internal contact unit 32 with a spring-loaded, strip-shaped contact element 321 which is fastened to an electrically insulating carrier element 323 by two screws 329.

[0052] Only the right screw 329 provides a point-by-point fixation of the contact element 321, which is designed as a spring plate, whereas the left screw 329 provides lateral guidance in an elongated hole 22. If the V-shaped, protruding section of the contact element 321 is compressed, the contact element 321 elongates. For this purpose, uniaxial mobility is provided by the guide in the elongated hole 322.

[0053] Above and below the contact element 321, the support element 323 has projecting protective webs 325 which project so far that only the V-shaped spring section of the contact element 321 protrudes from the pair of protective webs 325, while the contact plate and the screws 329 are protected from mechanical damage by abutting chassis frames of adjacent chassis.

[0054] The support element 323 has on its rear side a shoulder 324 of reduced circumference, via which it can be inserted into a slot-shaped recess in a side member, so that only the part of the support element 323 with the larger circumference, on which the exposed contact element 321 is held, rests on the outside of the side member.

[0055] Fig. Figure 7 shows an internal contact unit 32' which differs from the one previously described with reference to Fig. 6 only in that the support element 323 does not have any protective webs. Nevertheless, a certain degree of protection of the contact element 321 and the screws 329 is provided by mounting them in a recess in the support element.

[0056] Another variant of an internal contact unit 34 shows Fig. 8. There, a bolt-shaped contact element 341 is provided, which is beveled on both sides of its front end, extending from a vertical central axis, to form run-on slopes. The contact element 341 is slidably mounted in a bushing 342 against the force of a non-visible compression spring. The bushing 342 is made of brass, for example, to establish an electrical connection to the movable bolt, which serves as the contact element 341. The bushing 342 is accommodated in an electrically insulating support element 343.

[0057] Above and below the contact element 341, the support element 343 has projecting protective webs 345 which project far enough that a front section of the contact element 341 projects from the pair of protective webs 345, while the remaining section and the socket 342 are protected from mechanical damage by abutting chassis frames of adjacent chassis.

[0058] The carrier element 343 has on its rear side a shoulder 344 of reduced circumference, via which it can be inserted into a slot-shaped recess in a side member, so that only the larger part of the carrier element 343 in circumference, on which the socket 342 for the contact element 341 is held, rests on the outside of the side member.

[0059] Fig. 9 shows an internal contact unit 34' which differs from the one previously described with reference to Fig. 8 only in that the support element 343 has no protective webs. Nevertheless, the bushing 342 is protected because it is accommodated in a recess in the support element 323.

[0060] In Fig. Figure 10 shows an external contact unit 31 in a perspective view of the front. This comprises an electrically insulating support element 313 and a strip-shaped contact element 311 formed from a sheet metal strip. Its ends extend to the rear through slots 316 in the support element 313. Above and below the contact element 311, the support element 313 has projecting protective webs 315 that extend far enough to protect the contact element from mechanical damage caused by the abutting chassis frames of adjacent chassis.

[0061] A perspective view of the rear of the external contact unit 31 is shown in Fig. 11. End sections 318 of the contact element 311 are each fastened to the support element 323 with a screw 319. The end sections 318 also each have a plug-in contact tab 317 for connecting a flat plug connector known from automotive electrical systems.

[0062] Fig. 12 shows from above the left side member 21 of a chassis frame, which is equipped with an external contact unit 31 and an internal contact unit 34 with a spring-mounted, bolt-shaped contact element 341.

[0063] Fig. 13 is a top view of sections of the respective right side members 21 of two chassis frames during the stacking process. In Fig. 11 is the final position of the last one in the stack - the one in Fig. 11 left - chassis opposite the front one in the stack - of the one in Fig. 11 of the right chassis has not yet been reached. The outer contact unit 31 of the rear chassis and the elongated inner contact unit 32, equipped with a spring plate, are about to make contact.

[0064] When presented in Fig. 14, the final position of the chassis relative to each other is reached. The front section of the chassis frame 22 rests against the buffers 26 on the cross member 24 of the front chassis. The external contact unit 31 and the internal contact unit 34 overlap in a partial area of ​​their lengths, so that the protruding contact element 321 of the internal contact unit 32 touches the contact element of the external contact unit 31, thus forming an electrical connection between the adjacent chassis.

[0065] The Fig. 15 illustrated stackable chassis 2' is to the chassis 2 in Fig.1 is largely identical. The only addition is a loading unit 51, which is separate from the electronics unit 50 and is located within the chassis frame 20, between the side members 21. It is located behind the console 23 in the direction of travel and is secured with a fastening element 52 below the cross member 24.

Claims

[1] Stackable chassis (2; 2') for a shopping trolley (100), at least comprising a forwardly tapering chassis frame (20) with two side members (21) and with rollers (29) attached thereto and a vertical frame (40) with at least two side members (41), wherein the chassis (2) is stackable with further chassis (2; 2') with a stacking dimension S as a distance with respect to a longitudinal axis L of the chassis (2), characterized by , - that both side members each have at least one at least single-pole electrical external contact unit (31) on their respective outer side and at least one at least single-pole electrical internal contact unit (32; 32'; 34; 34') on their respective inner side; or that at least one of the side members (21) of the chassis frame (20) has at least one multi-pole electrical external contact unit on its outer side and at least one multi-pole electrical internal contact unit on its inner side and - that the at least one external contact unit (31) and the at least one internal contact unit (32; 32'; 34; 34') are arranged at a distance from one another with respect to the longitudinal axis L on the chassis frame (20) corresponding to the stacking dimension S. [2] Chassis (2; 2') according to claim 1, characterized by that both side members (21) each have at least one electrical external contact unit (31) and at least one electrical internal contact unit (32; 32'; 34; 34'). [3] Chassis (2; 2') according to claim 1, characterized by that a side member has at least one two-pole external contact unit and at least one two-pole internal contact unit on its inner side. [4] Chassis (2; 2') according to claim 1 or 3, characterized by that the two-pole contact units each have two contact surfaces arranged vertically one above the other. [5] Chassis (2; 2') according to claim 1 or 3, characterized by that the two-pole contact units each have two contact surfaces arranged horizontally one behind the other. [6] Chassis (2; 2') according to one of claims 1 to 5, characterized by in that on a side member (21) in a pair of an external contact unit (31) and an internal contact unit (32; 32'; 34; 34'), one contact unit in each case has a rigid contact element, and one contact unit in each case has a resilient or resiliently mounted contact element (321, 341), wherein the contact elements (321, 341) are each mounted on an electrically insulating carrier element (323, 343). [7] Chassis (2; 2') according to claim 6, characterized bythat the carrier elements (323, 343) each have at least one protective web (325, 345) below and above the contact elements (321, 341). [8] Chassis (2; 2') according to one of claims 1 to 7, characterized by that the external contact units (31) each have rigid contact elements and the internal contact units (32; 32'; 34; 34') each have resilient or resiliently mounted contact elements (321, 341). [9] Chassis (2; 2') according to one of claims 1 to 8, characterized by that the internal contact units each have rigid contact elements and the external contact units each have spring-loaded contact elements. [10] Chassis (2; 2') according to at least one of the preceding claims, characterized bythat at least in the case of contact units with spring-loaded or spring-loaded contact elements, the carrier elements (323, 343) are inserted into a recess in an inner and / or outer side surface of the side members (21). [11] Chassis (2; 2') according to at least one of the preceding claims, characterized by that the resilient contact elements (341) are bolt-shaped and are mounted displaceably against the force of a spring element in the support element (343) transversely to its longitudinal extent. [12] Chassis (2; 2') according to at least one of the preceding claims, characterized by that the resilient contact elements (321) are formed by a spring plate which has a contour which allows it to be elastically deformed transversely to the longitudinal extent of the side member (21) and thereby to be elongated in the longitudinal extent. [13] Chassis (2; 2') according to at least one of the preceding claims, characterized bythat the distance in the stacking dimension S is measured from a protruding contact point of the contact element (321, 341) of the inner contact unit (32; 32'; 34; 34') to the center of the contact element of the outer contact unit (31), wherein the length of the contact element of the outer contact unit (31) is at least 5% of the stacking dimension S. [14] Shopping trolley (100) with a chassis (2; 2'v) according to at least one of the preceding claims, with a shopping article receiving unit which has an upper, forwardly tapering shopping basket (10) with a pivotable rear wall flap (11) and / or a lower storage surface (14) which is enclosed by an articulated storage frame (16) which can be lifted with its rear end region when stacking several identical shopping trolleys (100). [15] Shopping cart (100) according to claim 14, characterized bythat the shopping article receiving unit is mounted on or on the chassis (2; 2') via at least three load cells; and that an electronics unit (50) is provided, to which the load cells (31, 32) are connected and which is connected to a loading unit (51) or which contains an integrated loading unit. [16] Shopping cart (100) according to claim 14 or 15, characterized by that the loading unit (51) is arranged within the chassis frame (20), between the side members (21). [17] Shopping cart (100) according to claim 14 or 15, characterized by that the vertical frame (40) comprises two lateral beams (41) and at least one transverse bar (42, 43, 44), and that the electronics unit (50) and / or the charging unit (51) is (are) arranged on a transverse bar (42, 43, 44, 45).

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