NO328974B1 - Foldable trundle - Google Patents

Abstract

A folding trolley comprising, in the knocked-out condition, a seat portion having a first and a second end and a trolley handle, a foot rest portion with a first and a second end and at least one front wheel connected to its first end, at least one axle element having · a first and a second end and with two rear wheels, one at each of the outermost corners (s). The seat member is at its other end, preferably in the front face region, rotatably coupled to the other end of the footrest member and / or the shaft member, for rotation about a transverse horizontal axis, and the shaft member is at its other end, preferably at the top of the front face, rotatably coupled to the foot rest member and / or the other end of the seat portion for rotation about a transverse horizontal axis.

Description

Field of the invention

The present invention relates to a collapsible trolley.

The background of the invention

Parents need some form of equipment for the daily transport of prams or prams for small children over distances where car transport or carrying is not suitable or possible. The most important products that meet this need are prams, prams, sports prams or umbrella prams. All of these types of strollers for transporting small children have advantages and disadvantages depending on size, weight, collapsibility, etc.

One problem with today's collapsible trolleys is that they are neither sufficiently compact, nor have a shape suitable for storage in hotel luggage rooms or for stacking in a home wardrobe, especially for those who live in small apartments in cities where living space is expensive and storage space is small. A suitcase-shaped pram, sports pram or umbrella trolley would therefore be well adapted for storage in a cloakroom or freely in an entrance hall.

Sports prams and prams for toddlers generally lack the ability to be folded into an object with standard luggage dimensions, which would make it easier to stack the pram, especially together with other luggage or carry it as cabin luggage on planes.

Although some trolleys can be folded into relatively small objects, they usually do not have a standardized design, and support rods, locking mechanisms, handles or wheels protrude, making the folded trolley vulnerable to hooking and entanglement in other luggage, or worse it will scratch up and damage other luggage or luggage parts. Therefore, sports and pushchairs often have to be sent as special baggage on flights, which makes it necessary to set aside extra time at check-in and to find the correct baggage drop-off and drop-off points at the airport. To protect the pram and to prevent the pram from damaging other luggage, it may be necessary to place the pram in a cover, but this can be difficult, and there is a risk that the cover will fall off. Such special luggage is often handled as carelessly as other luggage, and many families have experienced faults or damage to their prams/prams after a flight.

It would also be an advantage to have a pram or a pram that can be used all the way to and from the airport, as children often fall asleep or become tired and fatigued from long walks at airports. It is therefore even more important to make it possible to fit the trolleys in the luggage compartment above the seats on a plane, for example according to the International Air Transport Association (IATA). The size of allowed cabin baggage varies between the different airlines, but can for example be (length x width x height), 60 x 45 x 25 cm, 56 x 45 x 25 cm or 55 x 40 x 23 cm, and the sum of these three measurements should often not exceed, for example, 115 cm.

This means that collapsible trolleys are normally not allowed cabin baggage. Equally, being able to bring the pram in the cabin will be preferable for most parents of young children, as the distance from the airplane seats to the baggage claim area can be relatively long, as well as the delivery time for the baggage. There is therefore a need for a collapsible pushchair that is smaller and more compact when folded, without compromising stability, size and ease of use when folded out, so that it can function as a satisfactory pushchair for everyday use.

From American patent US 6,016,893, a multi-purpose travel suitcase is known in which two suitcase parts are spliced together by means of a scissor-like support element which provides separation and connection of the two suitcase parts in two different positions. However, the construction is complex and heavy, and is not useful as a children's sports car, and the dimensions of the entire suitcase are not according to the rules for hand luggage.

The German patent document DE 299 19 159 shows a suitcase with an outer framework consisting of a handle and two transport wheels in the lower corners as many suitcases are equipped with, but where the suitcase in the open state can also be used as a child seat. In addition, the framework can be folded out and larger wheels can be fitted so that it can be connected to a bicycle or used as a pram or pram. The latter wheels are, however, of considerable size, and must be carried next to or placed inside the suitcase and are required to be dismantled/mounted depending on the desired use.

Brief summary of invention

The purpose of the present invention is to provide a device which avoids the problems described above.

The properties defined in the attached independent claim characterize this device

More specifically, the invention relates to a collapsible wheelbarrow which, in its unfolded state, consists of: a seat part with a first and a second end and a wheelbarrow handle, a foot rest part with a first and a second end and at least one front wheel connected to its first end, in that at least one axle element with a first and a second end and with two rear wheels, one in each of the outermost corners of the first end(s). The seat part is at its other end, preferably in the front area, rotatably connected to the footrest part and/or the other end of the shaft member, for rotation about a transverse horizontal axis, and the shaft member is at its other end, preferably at the top of the front area, rotatably connected to the footrest part and/or the other end of the seat part for rotation around a transverse horizontal axis.

Brief description of the drawings

In order to make the invention easier to understand, the following discussions will refer to the attached drawings which are given as examples only, and are not limiting of the invention. The components' relative dimensions and positions in the drawings are only to support the principles in the described designs, and must not be perceived as limiting. Figure 1 shows a perspective view of a first embodiment of the carriage according to the present invention in a folded state.

Figure 2 shows a perspective view of the cart in Figure 1 in its assembled state.

Figure 3 shows a picture of a first embodiment of the carriage according to the present invention in a folded state seen from the side.

Figure 4 shows a more detailed picture of figure 3

Figure 5 shows how the cart shown in figure 3 can be combined.

Figure 6 further shows how the cart shown in figure 3 can be combined

Figure 7 shows the carriage in Figure 3 in a fully assembled state

Figure 8A-B shows the carriage in Figure 3 with additional equipment.

Figure 9 shows a perspective view of a third embodiment of the carriage according to the present invention in a folded state.

Figure 10 shows a perspective view of the carriage in Figure 9 in its assembled state.

Figure 11 shows a perspective view of a fourth embodiment of the carriage according to the present invention in a folded state. Figure 12 shows a perspective view of the wagon in Figure 11 in its assembled state.

Description of exemplary embodiments of the present invention

The present invention discloses a collapsible pram where all requirements for stability and user-friendliness for a modern baby pram in the folded state are satisfied, while at the same time it appears as a suitcase or even as a pilot case in the folded state.

The present invention will be described in four exemplary embodiments. Professionals in the field will still be able to imagine other embodiments within the scope of the invention.

In the further description, the following terminology is used, and must be understood as given unless otherwise stated.

The terms "pushchair" and "stroller" as they appear in the present application are used as general expressions for all types of transport carriages for a baby or a child such as a sports pram, umbrella pram, pram or the like.

The terms "front", "frontal" and "forward-facing" refer to the horizontal direction in which the child's face or chest faces when sitting in the pram during normal use.

Furthermore, with the expressions "backside", "rear" or "backwards" is meant the opposite horizontal direction towards which the child's back faces when sitting in the pram during normal use.

All axes, rotating parts, fastening devices, couplings, hinges and the like must be considered rotatable around axes that are horizontal and vertical in relation to the symmetrical plane through the pram.

With the expressions "lateral", "transverse" or "transverse" is meant in the same way the horizontal direction perpendicular to the symmetrical plane through the pram.

The term "longitunal" refers to the horizontal direction in the symmetrical plane through the pram.

Note also that the description and illustrations focus on the framework of the collapsible pram according to the present invention, but a fully equipped pram according to the present invention will of course also have additional support elements for the child, such as for example arm, back, head - and foot rests which are preferably adjustable, in addition to other additional functions and devices.

Figure 1 represents the pram structure 1 according to a first embodiment of the present invention in a folded state.

The pram has a seat part 2 connected to a foot rest 3, to which a rear strut element 4 is also connected. The connections between the elements are hinged connections which enable the said elements to rotate relative to each other in the plane of symmetry through the pram, as described below.

The seat part 2 consists of a seat plate 21 and a backrest 22 placed between the first side pieces 23 which have an essentially triangular shape on the right and left sides. In this embodiment, the seat plate 21 and the back support 22 are connected at an approximately 90 degree angle, and the side pieces 32 have essentially right-angled triangles with dimensions adapted to the dimensions of the seat plate and the back support, the elements forming a first half of a rectangular diagonally divided box. The frontal edge of the seat part is rotatably hinged to the footrest part 3 around a horizontal axis, such as in the frontal edge of the seat plate and/or the side pieces. The seat part is preferably made of hard or semi-hard material, so that it forms a protective shell, preferably with padding on the inside for the baby or child.

The seat part 2 preferably has a pram handle 24, which in the unfolded state is pushed upwards from the top of the seat part. The pram handle 24 is somewhat narrower than the seat part in this embodiment, and is intended to be connected with hinges to the upper edge of the seat part 2. It can be folded forward into the seat section when folding the pram for protection against dirt and damage. The pram handle is preferably also lockable at different angles, for adaptation to the person pushing the pram. The pushchair handle can also be telescopic in the vertical/longitudinal direction. Alternatively, the pram handle can be integrated into the backrest 22 or the first side parts 23, and possibly also telescopically (as described below).

The footrest part 3 has a similar design to the seat part, and essentially forms the other half of the above-mentioned rectangular box. The foot rest part 3 consists of a leg rest 32 and a wheel cap 31 at the bottom, and both elements are placed between other side parts 33 on the right and left side. The top edge of the foot rest part is rotatably hinged to the seat part, as in the top edge of the leg rest and/or the other side parts. The other side parts are mainly designed as right-angled triangles with dimensions adapted to the footrest and legrest dimensions, and the elements form a second half of a rectangular box which is divided diagonally. In this embodiment, the wheel cap 31 is rounded downwards in the front part as a cylinder part to make room for at least one front wheel 34 connected to the foot rest part, such as to the wheel caps 31 or the leg rest 32, alternatively via a strut. (not shown).

Under the seat part 2, at the back of the pram, an axle element 4 is rotatably connected to the foot rest part 3 by means of hinges. The axle element 4 consists of a longitudinal element 41, equipped with the axle end pieces 43 on the right and left side of its rear side, in which the rear wheels 42 are connected to the outer sides of the end pieces 43. Alternatively, the end pieces 43 can be fork-shaped (not shown). In this embodiment, the longitudinal member 41 forms a rectangular plate with a concave bent recess at the transverse lower end to accommodate the feet of the person wheeling the bar cart (as better shown in Figure 2). Alternative designs have also been considered, such as an H-shape or an inclined H-shape, an inverted Y-shape or even two parallel shafts.

The three wheels 34 and 42 are placed in an isosceles triangle, i.e. the front wheel is placed on the normal line to the two rear wheels. The distance between the rear wheels 42 is sufficient to make the carriage stable, and can be mounted to the respective wheel axles on the longitudinal element 41 and the end pieces 43 of the wheel axles towards the rear wheels 42 can be bent downwards vertically towards the wheels, so that an angular end piece is formed on the axle element 4 above the wheels. The axle element 4 can be hinged to the body of the pram with wheel suspension that enables rotation around the transverse axis of the body, and has a locking mechanism that enables it to be locked in a fixed position when the pram is expanded to full size. The axle element can preferably be lockable in an open position as illustrated in figure 1, at an angle of approximately 90 degrees in relation to the footrest part 3, and the angle can be adjusted so that an optimal distance between the front and rear wheels for stability and possibly for support of the seat part 2, more specifically seat plate 21, can be obtained. The longitudinal element 41 may optionally be made of semi-elastic material to provide suspension in the vertical direction. The shaft element 4 can alternatively be lockable in any position, such as for example with a locking mechanism in the hinge element, or with a fixing mechanism for the seat part 2.

In Figure 2, the pram is shown in a fully assembled state according to the first embodiment of the present invention seen from below, where it can be seen as a pilot case cut diagonally into two parts, where the same wheels are used to roll the pram when switched off, can be used to roll the pilot case. It should be noted that in addition to just looking like a suitcase, the folded stroller as shown in figure 2 can also have space for storage, such as for extra children's clothes. The pilot case's lower wall forms the footrest 31, and is slightly curved to provide space and protection for the rear wheels. The side walls of the pilot case are the first 23 and the second side part 33, which are halves more or less diagonally divided along the longitudinal sides of the side walls of the pilot case. The front wall forms the back rest 22 and the back wall the leg rest 31 as illustrated in Figure 2. As mentioned above, the longitudinal element 41 has a concave bent recess in the transverse lower edge to provide space for the feet of the person rolling the cart.

The axle end pieces 43 which have an angled position in relation to the longitudinal element 41, for example around 90 degrees, provide the necessary angle to be able to place the rear wheels 42 below the case and preferably in line with the front wheel 34's axis of rotation on the left and right side of the front wheel. The assembly of the wheels on a transverse line simplifies maneuvering when the assembled cart is to be rolled. Alternatively, a pair of wheels can be placed in a slightly lower position in the combined state so that only two of the wheels are in direct contact with the ground, so that the maneuvering characteristics can be further improved.

The front wheel 34 can be mounted in several ways, such as with two parallel vertical wheel carriers 35 on each side of the wheel or with other suitable mechanisms. In an alternative embodiment, a shackle can be used which is screwed onto the wheel fender 31, or other parts of the footrest element 3, rotated around a vertical or nearly vertical axis in the pram's symmetry plate, to contribute to the pram's maneuvering properties. The shackle can preferably be screwed onto a spring load in order to give the front wheel a self-regulating positioning effect. The screw mechanism can also have a locking mechanism to be able to lock it in a fixed position. Figures 3-7 illustrate a second embodiment of the pram 1 according to the present invention, and in particular the various steps for combining the pram into a suitcase-shaped box, more precisely a pilot case. Figure 3 illustrates the pram 1 seen from the side consisting of a seat part 2 with first side pieces 32 and a pram handle 24, a footrest part 3 with second side pieces 33 and the front wheel 34, and an axle element 4 with a longitudinal element 41 and rear wheel 42. The seat part 2 is connected to the leg rest capsule 3 which is hinged around a first axis 25, and the shaft element 4 is connected to the leg rest capsule 3 which is hinged around a second axis 45.

Figure 4 shows a detailed example of the hinge mechanism which connects the seat part 2 to the footrest part 3 around the first axis 25, and the shaft element 4 to the footrest part 3 around the second axis 45. The second axis 45 in this example placed below and/or in front of first axis, since the axle element 4 is located under the seat part 2 and extends to the rear of the pram. The hinge of the elements can be connected to each other, for example through synchronization, whereby rotation of one of the elements will lead to rotation of one or more other elements. Such synchronized rotation can, for example, be carried out by using gears or friction elements on the respective parts. Figure 4 is also intended to illustrate that an exchange ratio of the hinge between the different parts is possible with different sizes. The hinge of the seat part 2 and the shaft element 4 can therefore be connected to each other through a transmission gear or gear drive, such as gears that engage each other. This is illustrated in Figure 4, where the seat part 2 has a gear element 26 which is meshed into a gear element 46 belonging to shaft element 4. As the seat part 2 must rotate 180 degrees in relation to the footrest part 3, while the shaft element 4 only needs to rotate 90 degrees in relation to the foot rest relay element, the diameter of the seat part 2 gear element 26 is smaller than the diameter of the axle element 4 gear element 46. The ratio can be, for example, 2:1.

Synchronized rotation of the elements can, for example, make it possible to fold and unfold the pram with one hand, by, for example, only one element being rotated by placing the seat part 2 down on the footrest part 3. Locking and unlocking the elements in certain positions is done with one single trigger. The possibility of folding and/or unfolding the pram with just one handle gives the advantage that one hand is free to hold the child, for example in safety situations when, for example, getting on and off a train, tram, plane or going up and down stairs etc.

As already mentioned, the rear axle element is connected with hinges to the pushchair body as shown in figures 5-6. This enables rotation of the shaft member 4 downwards to a position adjacent to the rear part of the footrest member 3, parallel to the pilot case's vertical direction. In addition, the rear wheels 42 have a certain distance from each other so that they can be placed on the right and left side, parallel and in line with the front wheel 34 as shown in Figure 6. The seat part 2 is placed forward and down towards the first side pieces 23 near the second side pieces 33 so that the pram 1 is transformed into a pilot case, as shown in figures 5-6.1 figure 6, the pram handle is rotated up towards the outer side of the backrest 22, but it can alternatively be rotated in towards the seat part 2 before the pram is folded as mentioned in the first embodiment , so that it is hidden and protected inside the pilot case as shown in figure 7. Figure 7 also shows a second luggage handle 36 which is suitable for rolling the pilot case as a normal hand luggage. The handle can also be telescopically designed or possibly rotatable so that it can be placed on the underside of the seat part 2 or the rear wall of the footrest part 3 when not in use.

Figure 8A shows the pram according to a second embodiment of the present invention with additional equipment attached, in this case a rain and sun screen 50.

The screen 50 is rotatably mounted on the left and right first side pieces 23, and can be opened by rotating the front piece around a screen axis 51 as shown in figure 8B where the screen is unfolded. The screen provides protection against sun and/or rain, snow, and a certain degree of noise, and protects the child in the pram from the surroundings. In figures 8A-8B, the screen is mounted on the outside of the pram so that the rain will be directed away from the interior area, and can preferably be removable, in order to be able to place the screen inside the pram when it is to be folded into a suitcase. Alternatively, the pram can also be equipped so that it is possible to mount the screen on the inside, such as on the inside of the first side seats 23, so that it will be easier to fold it together at the same time as the pram is folded into a suitcase.

As shown in Figures 3 to 8, the other side pieces 33 need not cover parts of the outer sides of the front wheel(s), as this is up to the designer to design in relation to the visual appearance of the trolley. In the same way, the rear wheels 42 can be equipped to a greater or lesser extent with mud flaps, as indicated in the figures. The transverse distance between the rear cavities can be set according to what is appropriate for the pram's use and appearance, and they can also be positioned across the outer sides of the other side pieces 33 to increase stability (not shown). Alternatively, a "pop out" system can be used to increase this distance when the pram is in use.

In Figure 9, a third embodiment of the pram according to the present invention is illustrated with two front wheels 34 to improve the pram's stability. In particular, lateral stability has been increased to reduce the risk of it tipping over. The pram according to this embodiment also has an alternative pram handle 24. The handle is integrated into the first side pieces 23, and is telescopically extendable and lockable. The pram handle is preferably lockable in several different height positions, as well as in a retracted position, where the handle's transverse rod is located near the rear outside of the backrest 22, or in a recess in the backrest. As shown in the combined state in figure 10, it is possible to achieve a significant transverse distance between the two front wheels 34 at the same time that the rear wheels 42 can be placed outside on the right and left side of the front wheels. Alternatively, the transverse distance between the rear wheels may be less than the distance between the front wheels, which would make it possible for the rear wheels to fit between the front wheels in the folded state of the trolley (not shown).

Figure 9 also illustrates a single central hinge element 60 which connects all the main elements: Seat part 2, footrest part 3 and shaft element 4, which all rotate around the same axis. The central hinge can of course also have springs, stop elements, gear elements and locking elements to limit the elements' freedom of rotation and lock them in different positions in relation to each other as mentioned above.

In other alternative embodiments of the invention, the main elements seat part 2, footrest part 3 and shaft element 4 can be hinged in other relationships than mentioned previously, such that both footrest part 3 and shaft element 4 are hinged to seat part 2, or that both seat part 2 and footrest part 3 are the hinge for axle element 4. The preferred hinge that is chosen in each individual case depends on the design and functions of the pushchair's various elements.

Figures 11 and 12a show a fourth embodiment where the pram can have a closable wheel box part, so that water and dirt which is attached to the wheels after use does not drip out of the pram during transport, for example in a luggage compartment. This can for example consist of a segmented protective curtain 39 as shown in figure 12, which can be stored on the back of the wheel housing 31, or a pocket in this, and which can be pulled out and around the visible parts of the front and rear wheels and up to the edge of the leg rest 32 and/or the axle element 41. The side covers on the outer side of the outermost right and left wheels can also be included in such a design when the pram is folded, either as static covers or as sliding covers 33' integrated into the other side parts 33 as shown in figure 12. Alternatively, adaptations can be made for a separate cover that can be buttoned on the lower part of the trolley when it is folded.

In this embodiment, the luggage handle 38 is suggested to be designed as a telescopic handle with a grip roof which can be integrated into or on the footrest 3 or the shaft element 4.

As indicated in figures 11 and 12, the extended volume space constituted by the foot rest part 3 can be variable, and its most extreme embodiment only consist of the wheel housing 31 as a structural part which can close the seat part as a cover. Any volume size between a flat cover and a seat part 2 as exemplified above is conceivable according to the present invention. Likewise, seat part 2 can vary in design, as shown in figures 11 and 12, and can have round corners and transitions between the parts. Furthermore, one can also imagine the seat part as a single structural part, for example designed as a shell, or a seat-like shape, in which the sitting surface as well as back and side parts are integrated seamlessly with each other.

If desired, the pram can also be equipped with one or more shoulder straps (not shown) to be able to carry the pram over the shoulder in both unfolded and folded state, or as a rucksack in folded state, for example when ascending and descending stairs or when pushing terrain that is unsuitable for rolling the pram.

Claims (20)

1. A collapsible wheelbarrow (1) which in the unfolded state consists of: - a seat part (2) with a first and a second end and a wheelbarrow handle (24), - a footrest part (3) with a first and a second end and at least one front wheel (34) connected to its first end, - at least one axle element (4) with a first and a second end and with two rear wheels (42), one in each of the outermost corners of the first end, characterized in that the seat part (2) at its other end, preferably in the front area, is rotatably connected to the foot rest part (3) and/or the other end of the shaft element (4), for rotation around a transverse horizontal axis, and that the shaft element at its other end, preferably at the top of the front area, is rotatably connected to the foot rest part (3) and/or the other end of the seat part (2) for rotation around a transverse horizontal axis. 2. The collapsible trolley according to claim 1, characterized in that the seat part (2) can be closed next to the foot rest part (3) so that together they form an essentially closed box in a folded state of the trolley, preferably a completely closed box, and even more preferably, in the form of a suitcase. 3. The collapsible trolley according to claim 1 or 2, characterized in that the seat part (2), the footrest part (3) and the axle part (4) are all connected through one central hinge element (60) for rotation around the same axis. 4. The collapsible trolley according to claim 1 or 2, characterized in that the shaft element (4) is connected to the foot rest part (3) below and/or behind the connection of the seat part (2) to the foot rest part (3). 5. The collapsible trolley according to one of claims 1-4, characterized in that at least one of the following: the seat part (2), the foot rest part (3) and the shaft element (4) are lockable at least in their end positions, preferably in any angular position in relation to each other. 6. The collapsible trolley according to one of claims 1-5, characterized in that the angle of rotation between at least two of the following: the seat part (2), the foot rest part (3) and the shaft element (4), are synchronously dependent, preferably by means of a transmission, such as by gears or friction elements, and the transmission between the seat part (2) and the shaft element (4) are preferably in the 2:1 range. 7. The collapsible trolley according to one of claims 1-6, characterized in that the rear wheels (42) and the front wheel(s) (34) in their combined state lie on a transverse line, alternatively that the rear wheels (42) have a vertical position that is different from the front wheel(s) (34). 8. The collapsible trolley according to one of the preceding claims, characterized in that the axle element (4) can be placed against the surface at the back of the footrest part (3) in a folded state of the trolley. 9. The collapsible trolley according to one of the preceding claims, characterized in that the seat part (2) consists of a seat plate (21) connected to a backrest (22), both parts placed between the two first side parts, preferably in an essentially triangular shape, two or more parts are preferably integrated with each other, more preferably that the parts together form one element, even more preferably that the seat part (2) is made of a hard or partially hard material. 10. The collapsible trolley according to one of the preceding claims, characterized in that the foot rest part (3) consists of at least one leg rest (32) connected to a wheel cap (31), alternatively the wheel cap (31) and/or the leg rest (32) is placed between two other side parts, two or more parts are preferably integrated with each other, even more preferably that the parts together form one element. 11. The collapsible trolley according to one of the preceding claims, characterized in that the wheelbarrow handle (24) is rotatably connected to the seat part (2) for rotation around a transverse horizontal axis which enables rotation of the handle (24), and can preferably be locked at different angles in relation to the seat part (2), alternatively that the wheelbarrow handle ( 24) can be rotated inwards into the seat compartment and/or against the back surface of the backrest (22) when folding the trolley, and that the trolley handle is telescopically extendable in a direction in the trolley's symmetrical plane. 12. The collapsible trolley according to one of claims 1-7, characterized in that the trolley handle (24) is telescopically connected to or integrated in the seat part (2), preferably retractable out of the seat part (2), alternatively from the first side parts or the backrest (22), and preferably lockable in different height positions. 13. The collapsible trolley according to one of the preceding claims, characterized in that the front wheel(s) (34) is connected to the footrest part (3), preferably to the underside of the wheel cover (31), with parallel wheel holders on each side of the wheel(s). 14. The collapsible trolley according to one of the preceding claims, characterized in that the front wheel(s) (34) is connected to the footrest part (3) with a fork, preferably a swivel fork rotating around a substantially vertical or vertically tilted axis in the trolley's plane of symmetry, even more preferably that the fork has a spring load to achieve self-adjusted alignment of the front wheel(s) (34). 15. The collapsible trolley according to one of the preceding claims, characterized in that the footrest (3), at least in its front part, is curved around a part of the front wheel (34), around a transverse axis, to provide shielding of the front wheel (34) in an extended state of the trolley, and shielding for both the front (34) and rear wheels (42) in a combined state of the trolley. 16. The collapsible trolley according to one of the preceding claims, characterized in that the axle element (4) has axle end pieces or forks in an angled position in relation to the axle element on the left and right sides of its rear, distal first end, alternatively directed downwards in an extended state of the trolley, alternatively at approximately 90 degrees, in which the rear wheels (42) is connected on the sides of the low extreme points of the end parts. 17. The collapsible trolley according to one of the preceding claims, characterized in that the shaft element (4) has the form of a rectangular plate, a rectangular plate with a concave-bent recess in the transverse lower edge, an H, a tilted H, an upside-down Y, or consists of two separate shaft elements with first and second ends with at least one wheel in each outermost part of the first ends. 18. The collapsible trolley according to one of the preceding claims, characterized in that the size of the assembled trolley is within approximately (length x width x height) 60 x 45 x 25 cm, preferably 56 x 45 x 25 cm, and even more preferably within 55 x 4 x 23 cm, and alternatively that the sum of the three measurements does not exceed 115 cm. 19. The collapsible trolley according to one of the preceding claims, characterized in that the wheelbarrow has a luggage handle (38), rotatably or telescopically connected to the seat part (2), the footrest part (3) or the axle element (4), for rolling the wheelbarrow in a folded state. 20. The collapsible trolley according to one of the preceding claims, characterized in that the wheelbarrow is equipped with one or more straps so that the wheelbarrow can be carried over the shoulder both when folded and unfolded, or as a rucksack when folded.