The present invention relates to a wheel supposrt structure for a cart, e.g. for a wheelbarrow, having a supporting frame, the 5 wheel structure comprising two separate wheel axes each carryin

-} a wheel, each wheel axis being mounted on a holding arm, which is pivotable about a substantially vertical frame portion for pivoting 180° in a horizontal plane so as to enable selective positioning of each wheel in either an inner or an outer 10 position relative to the longitudinal central plane of the cart.

A similar wheel support structure is previously known from US-A-272858 . In the known structure, the pair of wheels are mounted in such a way that, in a first, inner position, the two

15 wheels are located below the front end of the load container of the cart for use as a conventional wheelbarrow to be pushed in forward direction and, in a second, outer position, the two wheels are located below the rear half of the load container fo use as a cart to be pulled in the opposite, backward direction,

20 wherein two handle rods are swung inwardly towards each other s as to form a combined pulling rod. When converting the wheelbarrow into a pulling cart or vice versa, a pair of nuts inside the load container have to be loosened, whereupon the wheelbarrow is turned upβide down to enable swinging of the

25 holding arms carrying the wheels into the other position.

Thereupon, the nuts inside the load container must be tightened again.

Another example of prior art is disclosed in the published 30 Swedish patent application 7801158-2, wherein a wheel support structure corresponding to the opening paragraph is suggested (but not described in detail) at the end of the description.

On the basis of this prior art, the object of the present 35 invention is to provide a wheel support structure, wherein a

pair of wheels can be easily shifted between inner and outer positions, even if cart is loaded, and wherein each wheel is securely held in a well-defined inner or outer position upon shifting the wheel positions and locking the respective holdin arm in a rigid position by means of a locking device.

This object is accomplished by the features stated in claim 1. Thus, each wheel can be easily swung into a respective inner o outer position while making rolling contact with the ground, whereby the cart does not necessarily have to be unloaded befo shifting the wheel positions. The outer position of a wheel pa will provide a good lateral stability when rolling the cart, whereas shifting to the inner position makes it possible to ro the wheelbarrow over rather narrow bridges, planks or the like Therefore, the cart is flexible and safe in use. Furthermore, by means of the extended plate members forming bearing flange surfaces and being selectively securable to each other and to the supporting frame at a rear location, each holding arm is securably lockable in the respective poβition, whereby oscillation of each wheel is avoided.

Suitable further features are stated in the claims 2 - 4. In particular, the embodiment defined in claim 4 will give the further advantage that a pair of rear support members of the frame (conventionally serving to support the cart in a sub¬ stantially horizontal rest position) can be replaced by a pair of rear wheels mounted in the same way as the first pair of wheels.

The invention will be explained further below with reference t the appended drawings illustrating a preferred embodiment with two alternative wheel support structures.

Fig. 1 is a side view of a cart, namely a wheelbarrow, in a horizontal rest position;

Fig. 2 is a side view of the wheelbarrow in a vertical ^ 5 rest position;

Fig. 3 shows the wheelbarrow from underneath;

Fig. 4 is a rear end view of the wheelbarrow; and 10

Figs. 5a and 5b show, in a larger scale, two alternative embodiments of the wheel support structure for one of the two wheels of the wheelbarrow.

15 The wheelbarrow shown in figs. 1 - 4 comprises a load container

1 made of a suitable rigid and resistant material, e.g. a metallic plate material, and a frame, which supports the load container and is integral with a wheel support structure.

20 The frame structure is preferably made of tubular members, e.g. of plated steel or aluminium, and comprises two longitudinal side members 2,3 (βee fig. 3) which are extended rearwardly int slightly outwardly projecting rear portions 2a,3a provided with handles 4,5. The rear portions 2a,3a are connected by a rear,

25 transversal frame member 6 permanently fastened e.g. by welding

The side members 2,3 of the frame structure extend mutually in parallel at each side of the longitudinal central plane C (fig. 3) of the wheelbarrow. The front ends of the side members 2,3,

30 located approximately at a distance of one third of the length of the load container, from the front end thereof, are inte- ^* grally extended into a connecting frame member including up¬ wardly and transversally outwardly curved side portions 2b and 3b, respectively, and a transversal front portion 7, which is

35 located at a lower level (in the horizontal rest position of

fig. 1) than the side portions 2b, 3b. It will be seen from fig that the connecting front frame member 2b,3b,7 has a configura tion substantially corresponding to the contour of the load container 1 below the front end portion lb thereof, whereas the rear transversal frame element 6 is located substantially underneath the rear end portion la of the load container (compare also fig. 1). Hereby, lifting hooks (not shown) can easily be hooked onto the respective front side portions 2b, 3b and the rear frame member 6 (or at the rearwardly extending portions 2a,3a adjacent to the rear frame member 6) so as to conveniently lift the wheelbarrow safely in its frame. Moreov the transversal front portion 7 serves as an abutment (as previously known per se) when forwardly tilting the wheelbarr into the vertical rest position shown in fig. 2.

According to the invention, the wheelbarrow is provided with least one pair of wheels 8,9 mounted in a special wheel suppo structure, which is integral with the frame structure. In particular (see fig. 4), each wheel 8,9 is mounted for free rotation on separate wheel axes 10 and 11, respecitvely, each which is pivotable in a horizontal plane about a vertical piv axis 12 and 13, respectively, so that each wheel 8,9 can be shifted, by pivoting a respective holding arm forming an exte sion of each wheel axis, between an inner position 8,9 (fully drawn) and an outer position 8',9' (dash-dotted lines), these positions being located along a transverse imaginary line L which is perpendicular to the central longitudinal plane C of the wheelbarrow. In both positions 8,9 and 8', 9' the pair of wheels will support the frame slightly in front of the centre of gravity of the (loaded or empty) wheelbarrow. The outer positions 8', 9' will give the wheelbarrow an excellent trans¬ versal stability, whereas the inner positions 8,9 make it possible to roll the wheelbarrow on rather narrow bridges, planks or the like. Now, it iβ very easy to shift between the inner and outer positions of the pair of wheels by simply

pivoting the holding arm with the respective wheel axis about the respective pivot axis 12,13, even when the wheelbarrow is placed in its horizontal position (fig. 1) and even when it is loaded. Moreover, the shifting is facilitated by the fact that

A 5 the wheels make rolling contact with the ground during pivoting

The wheel support structure for supporting the wheel 8 (the support structure for the other wheel 9 being identical and therefore not shown in detail) is illustrated in larger scale i 10 fig. 5a, whereas a slightly modified embodiment thereof iβ show in fig. 5b.

Referring to fig. 5a, there is shown a tubular frame portion 14 fastened by welding to and projecting vertically downwards fro

15 the frame side member 2 along the pivot axis 12. At the inside of the tubular frame portion 14, a tubular stud 15 is rotatabl journalled so as to permit rotation thereof about the pivot ax 12. At its lower end, the stud 15 is fastened by welding to th above-mentioned, horizontally extending holding arm 16, which

20 likewise tubular and constitutes the wheel axis or shaft 10 at its outer, free end portion. The wheel 8 is provided with a hu 17, which is freely rotatable on the axis or shaft 10 between two lateral holding flanges 18 and 19 rigidly fastened to the shaft .

25

In order to hold the vertical stud 15 in a fixed vertical position relative to the vertical frame portion 14, the stud 1 and the frame portion 14 are fastened by welding to horizontal plate members 20 and 21, respectively, forming bearing flange

30 surfaces 20a,21a in the region of the stud 15 and the frame portion 14.

The embodiment of fig. 5b differs from that of fig. 5a only in

) that the vertical, tubular stud 15' is rotatably journalled at 35 the outside or the vertical frame portion 14'.

As illustrated in fig. 1, the upper, horizontal plate member is fastened to the vertical support portion 14 at its front e portion and extends longitudinally rearwardly to a similar, r vertical frame portion 22, where it is likewise fastened by welding. Hereby, the upper horizontal plate member 20 (and th corresponding plate member 20' at the other side of the wheelbarrow, see fig. 3) is securely and rigidly connected to the frame structure. The lower, horizontal plate member 21 (a 21' at the other side) is fastened to the stud 15 (see fig. 5 at its central portion and extends in opposite directions therefrom, so that either one of its free end portions 21f (forward), 21r (rear) can be positioned under and in line wit the upper, rearwardly extending plate member 20. In either position, the lower, pivotable plate member 21 can be releasa secured to the upper, fixed plate member 20 by means of locki or fastening means 23, e.g. a pin through corresponding holes the plates 20,21 and a wing nut for securing the pin in its locking position. In the secured position, the Btud 15 will b held in an exact angular position relative to the frame porti 14, so that the holding arm 16 with the wheel axis is likewis exactly positioned along the transversal line L (fig. 3). Hereby, the wheels will not oscillate when rolling on the ground.

Two rear support members 24, each in the form of a plate ele bent into a closed, triangular, elongated shape, are provide with vertical holding stud portions 25, each fitting into the respective rear vertical frame portion 22, and are secured t the upper, horizontal plate members 20,20' by releasable loc or fastening means 23', e.g. identical to the means 23. The support members 24 are dimensioned so as to hold the wheelba in a substantially horizontal rest position.

If desired, the rear support members 24 can be replaced by a pair of rear wheels 8a,9a (illustrated by dash-dotted lines i figs. 1,2 and 3), which are mounted in the same way as the fr wheels 8,9. Since the wheel diameter is greater than the distance between the front and rear frame portions 14,22, one pair of wheels has to be placed in the inner position when th other pair is placed in the outer position, and vice versa. W such a wheel arrangement, preferably with the front wheels placed in the inner positions, the wheelbarrow can be pushed, without lifting in the handles 4,5, on the ground where the supporting ground surface is wide enough, whereas the wheelbarrow can be rolled on the front wheels only, while lifting in the handles 4,5, when passing over narrow passages such as planks or the like.

In order to achieve the desired simple shifting between the outer and inner wheel positions, while securing a rolling contact with the ground, it is essential that the respective wheel axis 10,11 extends in a horizontal plane perpendicular the respective pivot axis 12 or 13. Hereby, the wheel will follow a circular path with its axis directed towards the piv axis when the holding arm is swung around the pivot axis. However, the holding arm may be inclined and/or curved as lon as the wheel axis extends in such a horizontal plane perpen- dicular to the pivot axis. As another feasable alternative, t holding arm may be secured to a fork-like bracket carrying th respective wheel axis. However, the illustrated embodiment wi a rectilinear, rather short holding arm constituting an exten sion of the wheel axis seems to be the most practical one.

The wheel support structure described above may be modified within the scope of the appended claims, e.g. as regards the frame structure and the wheel holding arms. Also, the locking the respective holding arm in each transversal position may achieved by other means, e.g. by snap locking means, or fastening means without loose parts .