CHASSIS FOR A ROLLCART AND ROLLCART

Description

TECHNICAL FIELD

[0001] The present invention relates generally and more particularly to a chassis for a pushcart and a pushcart. TECHNICAL BACKGROUND

[0002] Push carts are generally known, such as shopping carts, strollers, rolling bases (e.g. for garbage cans), and the like.

[0003] There are various solutions for negotiating stairs or steps with such push carts. For example, shopping carts are known to have different front and rear wheels. If the rear wheels are larger than the front wheels, the front wheels can be lifted more easily than with carts with the same size wheels.

[0004] Furthermore, sack trucks are known to have multiple wheels on one side of an axle, mounted to rotate around a center point, to overcome steps. For example, patent DE 10 2015 210 613 B3 describes a trolley for transporting heavy loads over obstacles, with the trolley's wheels mounted to allow them to fold.

[0005] Furthermore, published patent application DE 10 2016 013 516 A1 describes a transport trolley for use on ships that is said to be able to overcome coamings and maneuver in narrow aisles. A hand truck for carrying heavy weights up and down stairs is known from patent application US 8,231,131 B1.

[0006] The object of the invention is to provide an improved chassis for a pushcart and a pushcart. SUMMARY

[0007] The present invention relates to a chassis for a push truck according to independent claim 1. Further features emerge from the dependent claims. BRIEF DESCRIPTION OF THE DRAWING

[0008] Embodiments will now be described by way of example and with reference to the accompanying drawings in which: Fig. 1 illustrates a first embodiment of a chassis for a pushcart according to the present disclosure; Fig. 2 the chassis of Fig. 1 in which an alternative guide is provided between the front axle and the rear axle; Fig. 3 illustrates another embodiment of a landing gear according to the present disclosure; Fig. 4 shows another embodiment of a landing gear according to the present disclosure; Fig, 5 shows another embodiment of a landing gear according to the present disclosure; Fig. 6 shows an example of how a pushcart may be used in accordance with the present disclosure; Fig. 7 shows another embodiment of a landing gear according to the present disclosure; Fig. 8 shows another embodiment of a pushcart according to the present disclosure and an exemplary use of the pushcart; and Fig. 9 shows another embodiment of a chassis for a pushcart according to the present disclosure.

[0009] However, only those embodiments which fall under the definition according to claim 1 are to be regarded as in accordance with the invention. DESCRIPTION OF EMBODIMENTS

[0010] Before a detailed description of the embodiment with reference to Fig. 1 First, general explanations of the embodiments follow.

[0011] As already described, push carts are generally known. However, it may be difficult to climb one or more steps (of a staircase) with conventional push carts, for example, because the wheel spacing does not correspond to the length of several steps, or the wheels are too large, or similar reasons.

[0012] Furthermore, for carts with different wheel sizes, it may be problematic to raise the rear wheels or rear axle to overcome an obstacle. In general, such known devices may not be suitable for negotiating individual steps, but rather only a (short) flight of stairs as a whole, if at all.

[0013] Therefore, some embodiments not according to the invention relate to a chassis for a pushcart, comprising: a rear axle and a front axle, which are arranged one behind the other in the pushing direction, wherein an axle distance can be changed by an elastic tensioning mechanism, wherein the axle distance can be reduced by building up a tensile stress in the elastic tensioning mechanism by adjusting the front axle and / or the rear axle.

[0014] A pushcart according to the present disclosure may be any type of cart capable of moving by exerting a pushing force in the pushing direction (i.e., by pushing). Thus, a pushcart according to the disclosure may include, for example, a stroller, a hand truck, a shopping cart, a handcart, and the like.

[0015] The rear axle and the front axle can be designed to be movable or to allow wheel movement, although the present disclosure is not limited thereto. For example, only one of the axles can have such a mechanism.

[0016] Furthermore, the axles may also have different or the same axle types, which may include, for example: fixed axle, rotating axle, axle journal, axle stub, solid axle, hollow axle. For example, the rear axle may be implemented with a fixed axle, while the front axle is implemented with axle stub, without limiting the present disclosure thereto.

[0017] In some designs, the rear axle is fixed, so only the front axle is adjustable, allowing the tension to be built up. However, this does not mean that the rear axle wheels cannot be steered, but rather that the axle position cannot be changed in the direction of thrust.

[0018] The wheelbase, i.e., the distance between the front and rear axles, is adjustable. This can be achieved using an elastic tensioning mechanism that allows the position of the front axle relative to the rear axle (or vice versa) to be changed.

[0019] The elastic tensioning mechanism can, for example, be located on the underbody of the pushcart. The front axle is connected to the rear axle by the elastic tensioning mechanism.

[0020] If a tensile stress is built up in the elastic tensioning mechanism, for example by pressure against the front axle, the wheelbase can be reduced by changing the position of the front axle, more precisely by adjusting the front axle towards the rear axle.

[0021] To adjust the front axle and / or the rear axle, it is conceivable that these can be adjusted, for example, with a motor, either by building up the tensile stress directly through the motor, or by directly adjusting the front axle and / or the rear axle, which builds up the tensile stress.

[0022] In some embodiments, the tension can be built up by manually applying pressure or force to the front axle in the opposite direction to the direction of thrust. For example, the pusher carriage can be pushed against an obstacle, such as a stair, thereby reducing the axle distance.

[0023] In some embodiments, the elastic tensioning mechanism is configured to increase the center distance by reducing the tensile stress.

[0024] For example, if the manual pressure is released, e.g. by lifting the front axle above the step, e.g. by tilting the pushcart, the tension can be released, thereby returning the front axle to its original position.

[0025] In some embodiments, the elastic tensioning mechanism includes at least one biasing element.

[0026] The at least one prestressing element may comprise, for example, a spring, an (elastic) band (or a combination), a gas tension spring, a hydraulic spring, and / or the like.

[0027] In some embodiments, the elastic tensioning mechanism includes at least one damper.

[0028] In the damper, for example, the necessary tensile stress can be built up by reducing the internal pressure when adjusting the front axle.

[0029] The at least one damper can also be part of a sliding device that allows the front axle to be adjusted with little effort.

[0030] In general, the present disclosure is not limited to the application of tensile stress. In In some embodiments, a compressive stress is built up by adjusting the wheels, for example by providing an elastic pressure mechanism instead of an elastic tensioning mechanism.

[0031] For example, stiff springs (or only one stiff spring), e.g. in a guide, can be provided, which are reduced from a rest position when the front axle and / or the rear axle are adjusted, so that they build up a compressive force and can thus return the front axle and / or the rear axle to their basic position.

[0032] In such embodiments, dampers can also be used which build up excess pressure by adjusting the front axle and / or the rear axle, thus creating a compressive force.

[0033] In some embodiments, the front and / or rear axle is adjustable by a telescopic mechanism so that the change in the axle distance occurs on a straight line, while in some embodiments the adjustment of the front and / or rear axle occurs on a circular path, for example with a sliding construction.

[0034] In some embodiments, the front axle is movably connected to the rear axle via a slide rail. In such a slide rail, the tensioning mechanism according to the present disclosure can be implemented as (at least) a gas tension spring to apply the necessary tension to provide the functionality of a push cart according to the present disclosure.

[0035] Additionally or alternatively, in some embodiments, a damping (e.g. in the slide rail) can be provided so that the front axle does not jerk forward and can extend slowly (similar to a self-closing door).

[0036] In general, the present disclosure is not limited to pushing a pushcart according to the present disclosure, since it can in principle also be pulled, wherein when pulling, the rear axle can be adjusted instead of the front axle if only one axle is adjustable, and thus the tensile stress is built up.

[0037] Some embodiments relate to a pushcart as described herein.

[0038] In some embodiments, the push carriage further comprises: a transport device coupled to the chassis.

[0039] The transport device can be designed such that any goods can be transported therein (e.g., purchases in the case of a shopping cart, a child in the case of a stroller, and the like). However, the transport device can also be designed in such a way that it can be used flexibly for various goods.

[0040] The transport device may, for example, have a rectangular base plate, a rectangular rear wall, and two triangular side walls, without limiting the present disclosure thereto.

[0041] The base plate can incorporate an Isofix attachment point so that it can be used as a child seat or for attaching child seats (e.g., infant car seats, buggy seats, carrycots). The triangular side panels can be used in such a way that a child seat can be attached to the sloping upper edges.

[0042] In some embodiments, the transport device is removably attached to the chassis.

[0043] For example, when shopping with a toddler, the child typically remains in their car seat, which is placed in a shopping cart, or the child is transferred from their car seat to the shopping cart. This may require waking the child, which is typically undesirable.

[0044] In another case, if you first pick up a shopping cart from a cart collection point, the child may have to be left unattended or carried, which may also be undesirable.

[0045] A similar problem can arise when returning home from shopping, as it is typically difficult to carry the shopping and the child into the apartment (which may be on an upper floor).

[0046] It is therefore desirable if the transport device can be used as a child seat at the same time and the child and shopping can be transported in the pushchair at the same time.

[0047] After shopping, the transport device can be detached from the chassis and both can be stored separately in a vehicle. For example, the transport device can then be used again as a child seat in the vehicle.

[0048] In some embodiments, the transport device is coupled to the chassis.

[0049] The transport device can be fixed to the chassis so that it is immobile, or it can be mounted so that it can rotate.

[0050] In such embodiments, the push carriage further comprises: at least one joint connecting the transport device to the chassis so that a tilt and / or rotation angle between the transport device and the chassis can be adjusted.

[0051] The joint can be any type of joint, e.g. a ball joint or two axle joints if both the tilt and rotation angle are to be adjustable, or an axle joint to change only the tilt angle, or an axle joint to change only the rotation angle.

[0052] In some embodiments, the tilt angle is determined with respect to a horizontal axis and the rotation angle with respect to a vertical axis, without limiting the present disclosure thereto.

[0053] In such embodiments, a change in the angle of rotation corresponds to a rotation of the transport device parallel to the chassis. A change in the tilt angle then changes the angle between the transport device and the chassis.

[0054] In some embodiments, at least one of the tilt and rotation angles can be fixed.

[0055] When climbing stairs or staying on escalators, the transport device can be set to a position parallel to the steps, so that the contents of the transport device are protected from falling out.

[0056] For example, the joint or joints can have a function that allows an angle to be set, e.g. by allowing the joint to lock into any angle.

[0057] In some embodiments, the push carriage further comprises: a pushing device which is pivotally attached to the transport device and / or to the chassis.

[0058] The pushing device may comprise one or more rods with which the push cart can be pushed.

[0059] Furthermore, the angle of the pusher device with the chassis and / or the transport device can also be variable. For example, the pusher device can be folded over the transport device to fulfill a roll bar function. Furthermore, the pusher device can be set at any desired angle, for example, parallel to the chassis, so that a pusher according to the present disclosure can also be towed as a trailer.

[0060] Returning to the Fig. 1 , this illustrates a first embodiment of a chassis 1 for a push truck according to the present disclosure.

[0061] The chassis 1 has a rear axle 2, which is connected to a front axle 4 via an elastic tensioning mechanism 3. Wheels 5 (which remain without reference symbols in the following figures) are also attached to both the rear and front axles 2 and 4.

[0062] The front axle is embedded in a guide (not shown) of the rear axle and coupled to the rear axle via two preload elements 6 (here: springs).

[0063] If a tensile stress is built up in the elastic tensioning mechanism 3, ie, if the springs 6 are tensioned by adjusting the front axle 4, the axle distance between the rear axle 2 and the front axle 4 is reduced. At the same time, a tensioning force acts which increases the axle distance again when the tensile stress is released.

[0064] Fig. 2 schematically depicts a chassis 1' in which an alternative guide 7 is provided between the front axle 4 and the rear axle 2. The guide 7 contains ball bearings that allow the front axle to slide.

[0065] The same elastic tensioning mechanism is provided in the chassis 1' as in the chassis 1, but is not shown here for the sake of simplicity.

[0066] Fig. 3 illustrates another embodiment of a landing gear 10 according to the present disclosure.

[0067] Here, a front axle 11 lies in a guide 12, whereby the guide 12 is firmly connected to a rear axle 13.

[0068] In this embodiment, the guide is designed as a slide rail.

[0069] Both the front axle 11 and the guide 12 have a fastening device 14, which can be used to implement an elastic tensioning mechanism. In this embodiment, a spring 15 is tensioned on one side of the fastening device, while an elastic band 16 is tensioned on the other side.

[0070] This also illustrates that the elastic tensioning mechanism can be implemented in various ways. In some embodiments, a spring or elastic band can be tensioned on both sides.

[0071] Fig. 4 shows another embodiment of a landing gear 20 according to the present disclosure.

[0072] A front axle 21 is located in a guide 22 of a rear axle 23. Springs 24 are tensioned between the front axle and the rear axle as an elastic tensioning mechanism.

[0073] Fig. 5 shows another embodiment of a landing gear 30 according to the present disclosure.

[0074] A front axle 31 has two longitudinal struts 32 that engage in tubes 33 attached to a rear axle 34 and are movably mounted therein. Conversely, the rear axle 34 has longitudinal struts 35 that engage in tubes 36 attached to the front axle 31 and are movably mounted therein. This provides a guide that allows the front axle 31 and the rear axle 34 to be adjusted equally, thus creating a tensile stress in an elastic tensioning mechanism.

[0075] The elastic tensioning mechanism comprises pre-tensioning elements 37, each mounted between cross struts 38 and 39, wherein the cross struts 38 and 39 are connected to the front axle 31 and the rear axle 34, respectively, via the longitudinal struts 32 and 35.

[0076] Fig. 6 shows an example of how a push carriage 41 may be used according to the present disclosure.

[0077] In this embodiment, the push carriage 41 has the chassis 20, which in connection with Fig. 4 described, without limiting the present disclosure thereto.

[0078] Furthermore, the push carriage 41 has a transport device 42 which is coupled to the chassis via a joint 43 and to which a pushing device 44 is attached.

[0079] Fig. 6a ) shows how the push cart 41 stands with a front wheel 45 on a step 46. The front wheel 45 is on the end of a higher step 47 and a rear wheel 48 is on a lower step 49.

[0080] In this embodiment, the transport device 42 is forty centimeters wide and sixty centimeters long so that two standardized beverage crates can be accommodated one behind the other, without limiting the present disclosure thereto.

[0081] For example, suitcases can also be attached between the side walls of the transport device 42.

[0082] Furthermore, the walls of the transport device 42 and the sliding device 44 are foldable.

[0083] The pushing device 44 is pivotally mounted on the transport device 42 so that a pushing angle and pushing height can be adjusted. Furthermore, depending on the adjusted height of the pushing device 44, the pushing device can serve as a roll bar when the push cart 41 is attached to a bicycle as a trailer, for example.

[0084] The front wheels 45 and rear wheels 48 have a wheel diameter of twenty centimeters, without limiting the present disclosure thereto. In this embodiment, the front wheels 48 are not pivotally mounted so that the push cart can be used to climb stairs. However, in some embodiments, the front wheels are pivotally mounted (i.e., rotatable about an axis perpendicular to the ground), and in some embodiments, the pivoting of the front wheels can be additionally blocked for climbing stairs.

[0085] Fig. 6b ) shows that both the transport device 42 and the pusher device 44 can be tilted. The transport device 42 can also generally be rotated, as described herein, but this is not shown here. The transport device 42 is tilted such that its base 50 runs parallel to a surface of a stair step.

[0086] Furthermore, the sliding device 44 is tilted opposite to the tilting direction of the transport device 42.

[0087] Fig. 6c ) shows how the landing gear according to the present disclosure is reduced in size by pressing the front wheel against the face of the stair step 47 while raising the rear wheel so that the wheelbase is reduced and a tensile stress is built up in the elastic tensioning mechanism 24 of the landing gear 20.

[0088] Fig 6d ) finally shows the state of the push carriage 41 after the front wheel has been raised over the front of the step 47, so that the tensile stress has been reduced and the axle distance has increased again. For this purpose, an additional brake (not shown) is provided, which is designed to lock the rear wheels so that the rear wheels are firmly positioned when the front axle is raised.

[0089] Overall, the pushcar 41 is now one step higher than in the Fig. 6a ) and the process can be repeated until the stairs are overcome.

[0090] However, the present disclosure is not limited to the embodiments described in the drawings. For example, a push cart according to the present disclosure may also include a locking pawl configured to prevent the push cart from rolling backward when activated (e.g., by pushing or pulling). Thus, a heavy load can be transported up stairs with the push cart without the cart rolling backward.

[0091] The locking pawl can be connected to the rear axle (in some embodiments additionally or alternatively to the front axle), preventing the pushchair from rolling backward on the stairs while still allowing pushing in the direction of travel (e.g., up the stairs). The locking pawl can be deactivated, for example, on level ground, allowing the pushchair to be pulled.

[0092] Embodiments according to the invention relate to a chassis for a push truck, comprising: a rear axle and a front axle, which are arranged one behind the other in the pushing direction, wherein an axle distance can be changed by an elastic tensioning mechanism, wherein the axle distance can be increased by building up a mechanical tension in the elastic tensioning mechanism by adjusting the front axle and / or the rear axle.

[0093] In such embodiments according to the invention, a similar or different elastic tensioning mechanism than that described above can be used. In such an elastic tensioning mechanism, the mechanical stress (e.g., tensile stress or compressive stress) can be applied in a different direction than in the non-inventive embodiments described above, so that descending stairs can be facilitated with such a chassis.

[0094] For example, a pushchair with such a chassis can be pushed or pulled down stairs. However, pushing the pushchair down if the opening of the pushchair (e.g., on a stroller) is facing downwards can be problematic, as in such cases the contents could be lost (although, as described above, an adjustable transport device may be available that can be adjusted to prevent the contents from being lost). If the pushchair is pulled (i.e., pulled backward down stairs), this can, in most cases, ensure that the contents do not fall out.

[0095] So, if you pull a pushcart with such a chassis down the stairs, you can park the front axle on the top step, while increasing the wheelbase by building up the mechanical tension by placing the rear axle wheels on a lower step (at least two steps away from the step on which the front axle is located). If you place the rear axle wheels on the lower step, you can raise the front axle, reducing the mechanical tension and thus reducing the wheelbase, allowing the front axle to be placed on a lower step than before.

[0096] In embodiments according to the invention, the elastic tensioning mechanism is designed to reduce the center distance by reducing the mechanical tension.

[0097] The elastic tensioning mechanism may, for example, comprise an elastic band that is permanently mounted on the pushchair or that can be manually fastened when stair descent is required.

[0098] The elastic band can be wrapped around the front axle or otherwise connected to it. It can also be attached to another location on the pushcart, such as the rear axle, a pushing device (e.g., a handle), or the like.

[0099] In some embodiments, the elastic band may be wrapped around the handle of the pushcart to facilitate manual assembly or disassembly.

[0100] The elastic band may comprise a fabric band, a metal band, a spring band, or the like. However, the elastic tensioning mechanism may alternatively or additionally comprise a preloading element (e.g., a mechanical spring, a hydraulic spring, a pneumatic spring, a damper, or the like).

[0101] Some embodiments relate to a pushcart with such a chassis.

[0102] In some embodiments, a chassis for a push cart according to the present disclosure includes one or both types of elastic tensioning mechanisms so that both ascent and descent of stairs can be facilitated.

[0103] In other words, some embodiments relate to a chassis for a pushcart, comprising: a rear axle and a front axle arranged one behind the other in the pushing direction; a first elastic tensioning mechanism configured to change an axle distance between the rear axle and the front axle, wherein the axle distance can be reduced by building up a tensile stress in the first elastic tensioning mechanism by adjusting the front axle and / or the rear axle; and a second elastic tensioning mechanism configured to change an axle distance between the rear axle and the front axle, wherein the axle distance can be increased by building up a mechanical stress in the second elastic tensioning mechanism by adjusting the front axle and / or the rear axle.

[0104] Fig. 7 shows a chassis 60 for a pushcart according to the present disclosure, wherein an axle distance can be increased by building up a tensile stress (as mechanical stress) in an elastic tensioning mechanism and wherein the elastic tensioning mechanism is configured to reduce the axle distance by reducing the tensile stress.

[0105] The chassis 60 comprises a front axle 61 and a rear axle 63, with the front axle 61 located in a guide 62 of the rear axle. Furthermore, an elastic band 64 is wrapped around the front and rear axles, so that tensile stress builds up in the elastic band 64 when the axle distance is increased, as described herein, thus facilitating, for example, descending stairs.

[0106] Fig. 8 shows a pusher carriage 70 according to the present disclosure, which is constructed similarly to the pusher carriage 40 (described in Fig. 6 ), which, however, does not contain the chassis 20, but a chassis whose rear axle and whose front axle are adjustable within one another, and wherein an axle distance is variable by means of an elastic tensioning mechanism, wherein the axle distance can be increased by building up a tensile stress in the elastic tensioning mechanism by adjusting the front axle and / or the rear axle.

[0107] The elastic tensioning mechanism in this embodiment is an elastic band 71 that is attached to the front axle, guided around the rear axle, and wrapped around the handle of the pushcart 70. By means of a clamping buckle 72, the elastic band 71 is fastened to itself so that it is pretensioned to a predetermined degree.

[0108] When the push carriage 70 is pulled down a flight of stairs as described above, the tension in the elastic band 71 is increased when the center distance is increased from a basic position, as in Fig. 8a ) is shown.

[0109] In Fig 8b ) shows how the center distance is reduced by reducing the tensile stress so that the elastic band is again tensioned to the predetermined degree.

[0110] Fig. 8c ) shows, similar to the Fig. 8a ), how the push carriage 70 can be pulled down another step by increasing the axle distance again.

[0111] Fig. 9 shows another embodiment of a chassis 80 for a pushcart according to the present disclosure.

[0112] The chassis 80 comprises a front axle 81 and a rear axle 83, wherein the front axle 81 is located in a guide 82 of the rear axle.

[0113] The chassis further includes a first elastic tensioning mechanism 84 which is configured to change an axle distance between the rear axle 83 and the front axle 81, wherein the axle distance can be reduced by building up a tensile stress in the first elastic tensioning mechanism 84 by adjusting the front axle 81 and / or the rear axle, and a second elastic tensioning mechanism 85 which is configured to change an axle distance between the rear axle 83 and the front axle 81, wherein the axle distance can be increased by building up a mechanical stress (in this embodiment a tensile stress) in the second elastic tensioning mechanism 85 by adjusting the front axle 81 and / or the rear axle 83.

[0114] The first elastic tensioning mechanism 84 includes two springs between the front axle 81 and the rear axle 83 and the second elastic tensioning mechanism 85 includes an elastic band wrapped around the front axle 81 and the rear axle 83.

[0115] Such a chassis may be provided on a pushcart according to the present disclosure so that both ascent and descent of stairs are facilitated. LIST OF REFERENCE SYMBOLS

[0116] 1; 1'; 10; 20; 30; 60; 80Chassis 2; 13; 23; 34, 63; 83Rear axle 3; 24Elastic tensioning mechanism 4; 11; 21; 31; 61, 81Front axle 5Wheels 6; 37Pre-tensioning element 7; 12; 22; 62; 82Guide 14Fastening device 15; 24; 84Spring 16; 64; 71; 85Elastic band 32, 35Longitudinal strut 33, 36Tube 38, 39Cross strut 40Example of use of a push cart 41; 70 Push cart 42 Transport device 43 Joint 44 Push device 45 Front wheel 46, 47, 49 Step 48 Rear wheel 50 Base of the transport device 72 Clamp buckle

Claims

1. Chassis for a pushcart, comprising: a rear axle (63; 83) and a front axle (61; 81), which are arranged one behind the other in the pushing direction, wherein a axle distance is variable by means of an resilient tensioning mechanism (64; 71; 84; 85), wherein the axle distance is increasable by generating a mechanical tension in the resilient tensioning mechanism (64; 71; 85) through adjustment of the front axle (61; 81) and / or the rear axle (63; 83), characterized in that the front axle (61; 81) is connected to the rear axle (63; 83) by the resilient tensioning mechanism.

2. Chassis according to claim 1, wherein the resilient tension mechanism (64; 71; 85) is configured to reduce the distance between axles by releasing the mechanical tension.

3. Pushcart with a chassis (60; 80) according to one of claims 1 or 2.

4. Chassis according to claim 1, wherein the resilient tension mechanism (64; 71; 84; 85) comprises a first resilient tension mechanism (84) and a second resilient tension mechanism (85), wherein the first resilient tension mechanism (84) is configured to vary the axle distance between the rear axle (83) and the front axle (81), wherein the axle distance is reducible by generating a tensile stress in the first resilient tension mechanism (84) by adjusting the front axle (81) and / or the rear axle (83); and wherein the second resilient tension mechanism (85) is configured to vary the axle distance between the rear axle (83) and the front axle (81), wherein the axle distance is increasable by building up a mechanical tension in the second resilient tension mechanism (85) by adjusting the front axle (81) and / or the rear axle (83).

5. Pushcart with a chassis (80) according to claim 4.