The present invention relates to a tow assembly for shopping, comprising a basket defined by a rectangular bottom, two opposing longitudinal walls, a first transverse wall at a first transverse end of the basket, and a second transverse wall at a second transverse end of the basket; and a tow member with a grip bar having a handgrip to be gripped by a hand of a person towing the tow assembly; wherein the tow member comprises at least one tow bar having a first end carrying the grip bar and a second end, which, at the first transverse end of the basket, is hingingly attached to the upper edge of one of said walls; wherein the tow member is swingable between a rest position and a towing position; wherein, in the rest position, the tow member extends in a plane defined by the upper edges of the longitudinal and transverse walls and lies completely outside the basket with the grip bar along the outside of the upper edge of the second transverse wall; wherein the angular distance of the tow bar between the towing position and rest position is at least 90°; and wherein the assembly further comprises at least one carrying brace mounted to the upper edges of the longitudinal side walls for carrying the basket by hand.

Such a towing assembly is known from US-7,275,758-B, issued Oct. 2, 2007. This document discloses a basket with carrying handles, two wheels and a tow handle. The basket has a rectangular bottom, two opposing transverse walls and two opposing longitudinal walls. The wheels are provided near the bottom, at one transverse end of the basket. The tow handle is attached in hinging manner to the upper edge of the basket at the other transverse end of the basket. A person using this assembly can either carry the assembly with the carrying handles or tow the assembly by towing the tow handle. If not used, a multiple of such towing assemblies require a large amount of storage space. Further, this known towing assembly is not very easy to handle.

The object of the present invention is to provide an improved tow assembly.

This object is achieved by providing a tow assembly for shopping according to the preamble of claim 1 , which tow assembly is characterised in that, viewed perpendicular to the upper side of the bottom of the basket, each wheel is provided at the underside of the bottom and lies entirely within the contour of the bottom, and in that a said wheel is provided at each corner of the bottom. A wheel lying entirely within the contour of the bottom means that, viewed in any direction parallel to the bottom, the wheel does not project beyond the outer boundary of the bottom. The outer boundary of the bottom is in fact the outer edge of the bottom, which coincides with the lower edge of the longitudinal and transverse walls. By providing a wheel in each corner and each wheel within the contour of the bottom, a stable running of the tow assembly over the floor and along obstructions is obtained. The four outer edges of the rectangular bottom serve as guiding edge for the basket when the basket contacts an obstruction, like the shoe of another shopping person or the support feet of a display rack in a shop. The guiding edges shield the wheels against such objects and prevent the wheels, and thus the tow assembly, from being caught behind the obstruction. Wheels in each corner ensure that at least two wheels contact the floor in case contact with an obstruction might cause a wheel being lifted from the ground. Additionally the arrangement of the wheels allows a multiple of such tow assemblies being stored as a pile of nested baskets.

In order to maximize the length of the tow bar for a basket with predetermined dimensions, the second end of the tow bar carries a hinge, which is attached to the upper edge of the first transverse wall. In this embodiment, the hinge axis extends outside the basket along the upper edge of the first transverse wall, whilst, in the rest position, the grip bar extends outside the basket along the upper edge of the second transverse wall. A further advantage is that the hinge does not hinder a person carrying the basket with the carrying brace.

In order to prevent the tow member from swinging downwards from the horizontal rest position, the tow member is provided with a stop lip, which, in the rest position rests, on the upper edge of a said longitudinal or transverse wall and extends from the tow member in the direction of the basket. As the stop lip does not extend in outward direction with respect to the basket, it is prevented from scratching people or surrounding objects.

According to a further preferred embodiment, the tow member is an essentially U-shaped bracket having two of said tow bars connected by said grip bar, and wherein the dimensions and shape of the inner contour of the U-shaped bracket essentially correspond to the dimensions and shape of the outer contour defined by the upper edges of the second transverse wall and the two longitudinal walls such that in the rest position the upper edges of the second transverse wall and the two longitudinal walls are enclosed by the U-shaped bracket. The U-shaped bracket provides an easy gripping of the tow member from all sides and the corresponding shape and dimensions minimize the space occupied by the tow member when in the rest position. According to a further embodiment, the distance from the grip bar to said floor is at least 72 cm and at most 80 cm, preferably about 76 cm, when the basket is placed on a horizontal floor and the tow member is in a vertical position. From an ergonomical view, this gripping height of 72 cm to 80 cm is convenient for people having a length up to about 183 cm. A gripping height of about 76 cm, is still comfortable for people having a length up to about 177 cm and can also be managed by people having a length of about 190 cm. Taking into account that the average length of man in Northern Europe is about 185 cm, that the most frequent users of such tow assemblies will be women, and that the length of most woman is smaller than 177 cm, a gripping height of at least about 76 cm is preferred. It is noted that relatively smaller people will not have problems with a (too) high - vertical - gripping height as they will, when using it, automatically place the tow member in a slanting position which is convenient for their length. Taking into account that the average length of people decreases with increasing age and that elder people are envisaged to be the main users of the assembly, said distance is at least 74 cm and preferably at most 78 cm.

Taking into account that in practise, on the one hand, the hinge axis of the hinge will lie at a distance R (for example R=14.75 mm) a little lower than the upper side of the upper edge, whilst on the other hand the wheels will increase the height of the upper edge of the basket with respect to the floor (when compared with a basket without wheels) with a distance Q (for example Q=17.50 mm), which will in practise have a value of at least R, one can also define the ergonomical gripping height as the sum of the length of the drag bar and the height of the basket. This results in a preferred embodiment, wherein the sum of the height of the basket and the length of the tow bar is at least 72 cm and at most 80 cm, such as about 76 cm, wherein the height of the basket is measured from the bottom to the upper edge of the walls, wherein it is additionally preferred when said sum is at least 74 cm and/or at most 78 cm.

With respect to the stability of the tow assembly against turning on its side, it is advantageous when the height of the basket is in the range of 45% to 55% of the length of the upper edge of a said longitudinal wall. In this respect it is additionally preferred when the length of the transverse wall is, measured at the bottom of the basket, in the range of 90% to 110% of the height of the basket. For stability against turning on its side, it is also advantageous when the track width of the wheels is in the range of 80% to 100% of the height of the basket. According to a further preferred embodiment of the invention a stable tow assembly having a good gripping height for the handgrip is obtained when the length of said upper edge is in the range of 47 cm to 51 cm, such as in the range of 48 cm to 50 cm, preferably about 49 cm. According to a further embodiment of the tow assembly according to the invention it is advantageous when, at least the upper edge of the first transverse wall, preferably the upper edge of each said transverse walls and each said longitudinal walls, is in cross section U shaped; when the opening of said U shaped upper edge lies at the outside of the basket and faces downwards; wherein the hinge is mounted against the outside of the outer leg of the U shaped upper edge of the first transverse wall; wherein the hinge has at its upper side a mounting arm having a downwardly facing ridge, the length of the mounting arm being equal to the width of the upper face of said upper edge to provide a locking engagement of the ridge behind the upper edge on the inside of the basket; and when a snap lip is provided on the lower side of the hinge for snapping engagement with the outer leg of the U shaped upper edge, the snap lip preferably snapping around the lower end of the outer leg. This allows a conventional prior art basket having a U- shaped outer edge to be used for obtaining a tow assembly according to the invention. Advantageously, each wheel is attached to the basket by a first mounting plate with carrying arms carrying a said wheel and a second mounting plate, wherein the first mounting plate is provided outside the basket against the bottom, wherein the second mounting plate is provided inside the basket on the bottom opposite the first mounting plate, and wherein one of said mounting plates is provided with locking arms extending through apertures in the bottom and engaging in locking apertures formed in the other of said mounting plates.

According to a further aspect, the invention relates to a converting set for converting a shopping basket into a tow assembly according to the invention. This converting set is characterized in that the basket is defined by a bottom, two opposing longitudinal walls and two opposing transverse walls and wherein the basket comprises at least one carrying brace mounted to the upper edges of the longitudinal side walls for carrying the basket by hand; and in that the converting set comprises

• at least two, preferably four, wheels adapted to be provided at the underside of the bottom of the basket and below the bottom of the basket; • a tow member having at a first end a grip bar with a handgrip to be gripped by a hand of a person towing the tow assembly and carrying at a second end a hinge adapted for attachment to the upper edge of a first one of said transverse walls of the basket. With respect to further preferred embodiments of the tow member, wheels or basket, reference is made to the dependent claims directed to the tow assembly.

The present invention will be elucidated further with reference to the drawings, wherein: Figure 1 shows a perspective view of a tow assembly according to the invention, looking inside the basket;

Figure 2 shows a perspective view of the tow assembly according to figure 1 , looking onto the lowerside of the basket and showing the basket upside down; Figure 3 shows the another tow assembly according to the invention similar to the one of figures 1 and 2, with the tow member in a tow position; Figure 4 shows a pile of nested tow assemblies according to figures 3; Figure 5 shows schematically that the tow assembly according to figure 3 fits to persons having a length up to at least 177 cm; Figure 6 shows as a detail a cross section of a hinge mounted on an upper edge; Figure 7 shows perspective view of the wheel and its mounting plates; and Figure 8 shows a perspective view of a tow member according to the invention.

Referring to figures 1-3, the tow assembly 1 according to the invention comprises a basket 2, a tow member 3 and four wheels 4.

The basket 2 has a rectangular bottom 5, two opposing longitudinal walls 6, 7 and two opposing transverse walls 8, 9. Each wall has an upper edge 10, 11 , 12, 13, respectively. These upper edges 10, 1 1 , 12, 13 have a U-shaped cross section with the opening of the U facing downwards. The basket further has two U-shaped carrying braces 14, which can swing, from the position shown in figures 1-3, around swing axis 15 according to arrow A to a position about vertically with respect to the bottom. This allows a person to carry the basket by hand. This basket - without tow member and wheels - is as such prior art and in use in supermarkets of Applicant. The dimensions of this basket are - see figure 2 -: height H about 26 cm; length LU, measured along the upper edge, about 49 cm; length LL, measured along the bottom, about 38 cm; width WU, measured along the upper edge, about 34 cm; and width WL, measured along the bottom, about 24 cm.

The tow member 3 is, see also figure 8, an essentially U-shaped bracket comprising a grip bar 16 and two parallel tow bars 17. The grip bar 16 connects the first ends of the tow bars 17. The other ends of the tow bars 17 carry a hinge 28. The other ends are bent at angles of about 90°, which bent parts form shafts 18 received in cylindrical apertures 20 of a hinge part 19. In the embodiment according to figures 1 , 2 and 8, the grip bar 16 is provided with handgrip 40 in the form of an additional brace. In the embodiment according to figures 3, 4 and 5, the handgrip 41 is just a part of the grip bar. In case the gripping bar 16 lies, in vertical position, sufficiently high above the ground for comfortable use by the intended users as handgrip 41 , the embodiment according to figures 3, 4 and 5 is preferred. In case in the vertical position, the gripping bar is not sufficiently high above the floor to serve as a handgrip, the additional brace 40 according to figures 1 , 2 and 8 is advantageous.

Referring also to figure 6 for details of the hinges 28, the hinge parts 19 are provided with a mounting arm 21 at the upper sides. The length X of the mounting arms is equal to the width Y of the upper face 22 of the upper edge 12 of the first transverse wall 8. The mounting arm 21 is at its free end provided with a downwardly facing ridge 23. Referring to figures 2 and 3 the ridge 23 catches behind the upper face 22 on the inside of the basket to provide a locking engagement. On the lower side of the hinge part 19, there is provided a snap lip 24 for snapping engagement of the lower end of the outer leg 25 of the U-shaped upper edge 12. The lower end 26 of the outer leg 25 is accommodated in a slit 27 defined between the snap lip 24 and the body of the hinge part 19. The construction of the hinge 28 allows for easy mounting of the tow member 3 to baskets 2 having a U-shaped upper edge. In this manner the tow member can easily be mounted on a prior art basket in order to convert it into a tow assembly according to the invention.

The tow member 3 further comprises two stop lips 29, which rest on the upper edges 10, 11 of longitudinal walls 6, 7 when the tow member 3 is in a horizontal position, called the rest position, see figure 2. In this horizontal, rest position, the tow member extends in a plane defined by the upper edges 10, 11 , 12 and 13 and lies completely outside the basket 2. As one can see in figure 2, the dimensions and shape of the inner contour of the U-shaped bracket 3 corresponds essentially with the dimensions and shape of the outer contour defined by the upper edges 11 , 13, 10 of the longitudinal wall 7, the second transverse wall 9 and the longitudinal wall 6. The U-shaped bracket encloses so to say the upper edges 1 1 , 13 and 10. The length of the tow bars 17 is preferably fixed, i.e. these lengths cannot be elongated or shortened.

Referring for details also to figure 7, each wheel 4 is attached to the basket 2 by a first mounting plate 29 with carrying arms 30 carrying the wheel 4 and a second mounting plate 31 , which is shown upside down in figure 7. The first mounting plate 29 is provided outside the basket 2 against the bottom 5. The second mounting plate 31 is provided inside the basket 2 on the bottom 5 opposite the first mounting plate 29. One of said mounting plates, in the figures the second mounting plate 32, is provided with locking arms 36 extending through apertures in the bottom 5 and engaging in locking apertures 32 formed in the other 32 of said mounting plates. The tow member can swing to and fro between the horizontal rest position shown in figure 2 and a towing position shown in figure 3. The angle β of the swing is larger than 90°. In order to limit the swing in the towing position a stop can be provided in the hinge 28. It is also possible to design the hinge 28 such that the shaft 18 is received in the aperture 20 with friction in order to allow the tow member 3 to stay in a position also when not supported in the hand of the user. The smaller the user is, the larger the angle β will be.

Figure 4 shows that a multiplicity of tow assemblies 1 according to the invention can be stacked as a nested pile 33. Such a nested pile requires a minimum of space for storage. Due to the wheels being arranged completely inside the horizontal contour of the bottom 5, the nesting depth is as large as possible and consequently the height of the pile is reduced to a minimum.

Figure 5 shows schematically that the tow assembly according to figures 1-4 fits to persons having a length up to at least 177 cm. In case of shorter persons, the angle β will become larger. In case the person might be longer than 174 cm, the person might need to bend his back a little or might lift the first end 34 a little from the floor 35.

Several preferred features of the invention are summarized in the next following clauses: 1] Tow assembly for shopping, comprising:

• a basket defined by a bottom, two opposing longitudinal walls ;

• at least two wheels;

• a tow member with a grip bar having a handgrip to be gripped by a hand of a person towing the tow assembly; characterised in that the wheels are provided on the bottom of the basket; in that the tow member comprises at least one tow bar having a first end carrying the grip bar and a second end carrying a hinge which mounts the tow bar to the basket; in that the hinge is attached to the upper edge of a first one of said transverse walls; in that the tow member is swingable between a rest position and a towing position; in that, in the rest position, the tow member extends in a plane defined by the upper edges of the longitudinal and transverse walls and lies completely outside the basket with the grip bar along the outside of the upper edge of the second one of said transverse walls; in that the angular distance of the tow bar between the towing position and rest position is at least 90°; and in that the assembly further comprises at least one carrying brace mounted to the upper edges of the longitudinal side walls for carrying the basket by hand. 2] Tow assembly according to clause 1 , wherein the tow member is an essentially U- shaped bracket having two of said tow bars connected by said grip bar.

3] Tow assembly according to clause 2, wherein the dimensions and shape of the inner contour of the U-shaped bracket essentially correspond to the dimensions and shape of the outer contour defined by the upper edges of the second transverse wall and the two longitudinal walls such that in the rest position the upper edges of the second transverse wall and the two longitudinal walls are enclosed by the U-shaped bracket.

4] Tow assembly according to clause 3, wherein the lengths of the tow bars 17 are fixed.

5] Tow assembly according to one of the preceding clauses, wherein the tow member is provided with a stop lip, which, in the rest position rests, on the upper edge of a said longitudinal or transverse wall.

6] Tow assembly according to one of the preceding clauses, wherein, when the basket is placed on a horizontal floor and the tow member is in a vertical position, the distance from the handgrip to said floor is at least 72 cm and at most 80 cm, such as about 76 cm. 7] Tow assembly according to clause 6, wherein said distance is at least 74 cm.

8] Tow assembly according to clause 6 or 7, wherein said distance is at most 78 cm.

9] Tow assembly according to one of the preceding clauses, wherein the sum of the height of the basket and the length of the tow bar is at least 72 cm and at most 80 cm, such as about 76 cm, wherein the height of the basket is measured from the bottom to the upper edge of the walls.

10] Tow assembly according to clause 9, wherein said sum is at least 74 cm.

11] Tow assembly according to clause 9 or 10, wherein said sum is at most 78 cm.

12] Tow assembly according to one of the preceding clauses, wherein the height of the basket is in the range of 45% to 55% of the length of the upper edge of a said longitudinal wall.

13] Tow assembly according to clause 12, wherein the length of the transverse wall is, measured at the bottom of the basket, in the range of 90% to 110% of the height of the basket.

14] Tow assembly according to clause 12 or 13, wherein the track width of the wheels is in the range of 80% to 100% of the height of the basket.

15] Tow assembly according to one of clauses 12-14, wherein the length of said upper edge is in the range of 47 cm to 51 cm, such as in the range of 48 cm to 50 cm, preferably about 49 cm.

16] Tow assembly according to one of the preceding clauses, wherein at least the upper edge of the first transverse wall, preferably the upper edge of each said transverse walls and each said longitudinal walls, is in cross section U shaped; wherein the opening of said U shaped upper edge lies at the outside of the basket and faces downwards; wherein the hinge is mounted against the outside of the outer leg of the U shaped upper edge of the first transverse wall; wherein the hinge has at its upper side a mounting arm having a downwardly facing ridge, the length of the mounting arm being equal to the width of the upper face of said upper edge to provide a locking engagement of the ridge catching behind the upper face on the inside of the basket; wherein a snap lip is provided on the lower side of the hinge for snapping engagement with the outer leg of the U shaped upper edge, the snap lip preferably snapping around the lower end of the outer leg.

17] Tow assembly according to one of the preceding clauses, wherein each wheel is attached to the basket by a first mounting plate with carrying arms carrying a said wheel and a second mounting plate, wherein the first mounting plate is provided outside the basket against the bottom, wherein the second mounting plate is provided inside the basket on the bottom opposite the first mounting plate, and wherein one of said mounting plates is provided with locking arms extending through apertures in the bottom and engaging in locking apertures formed in the other of said mounting plates. 18] Converting set for converting a shopping basket into a tow assembly according to one of the preceding clauses, wherein the basket is defined by a bottom, two opposing longitudinal walls and two opposing transverse walls and wherein the basket comprises at least one carrying brace mounted to the upper edges of the longitudinal side walls for carrying the basket by hand; wherein the converting set comprises • at least two wheels to be provided on the bottom of the basket; • a tow member with a grip bar having a handgrip to be gripped by a hand of a person towing the tow assembly.

19] Converting set according to clause 18, wherein the tow member comprises at least one tow bar having a first end carrying the grip bar and a second end carrying a hinge adapted for attachment to the upper edge of a first one of said transverse walls of the basket to allow swinging of the tow member over a distance of at least 90° between a rest position and a towing position; and wherein the tow member is adapted to extend, in the rest position, in a plane defined by the upper edges of the longitudinal and transverse walls and to lie completely outside the basket with the grip bar along the outside of the upper edge of the second one of said transverse walls of the basket. 20] Converting set according to one of clauses 18-19, wherein the tow member is an essentially U-shaped bracket having two of said tow bars connected by said grip bar. 21] Converting set according to clause 20, wherein the dimensions and shape of the inner contour of the U-shaped bracket essentially correspond to the dimensions and shape of the outer contour defined by the upper edges of the second transverse wall and the two longitudinal walls such that in the rest position the upper edges of the second transverse wall of the basket and the two longitudinal walls of the basket are enclosed by the U-shaped bracket.

22] Converting set according to one of the preceding clauses 18 - 21 , wherein the tow member is provided with a stop lip, which, in the rest position rests, on the upper edge of a said longitudinal or transverse wall of the basket. 23] Converting set according to one of the preceding clauses 18 - 22, wherein, when the basket is placed on a horizontal floor and the tow member is in a vertical position, the distance from the handgrip to said floor is at least 72 cm and at most 80 cm, such as about 76 cm. 24] Converting set according to clause 23, wherein said distance is at least 74 cm. 25] Converting set according to clause 23 or 24, wherein said distance is at most 78 cm. 26] Converting set according to one of the clauses 18-25, wherein the sum of the height of the basket and the length of the tow bar is at least 72 cm and at most 80 cm, such as about 76 cm, wherein the height of the basket is measured from the bottom to the upper edge of the walls. 27] Converting set according to clause 26, wherein said sum is at least 74 cm.

28] Converting set according to clause 26 or 27, wherein said sum is at most 78 cm 29] Converting set according to one of the clauses 18 - 28, wherein the track width of the wheels is in the range of 80% to 100% of the height of the basket. 30] Converting set according to one of the clauses 18 - 29, Comprising for each wheel a first mounting plate with carrying arms carrying a said wheel and a second mounting plate, wherein the first mounting plate is adapted for being provided outside the basket against the bottom, wherein the second mounting plate is adapted for being provided inside the basket on the bottom opposite the first mounting plate, and wherein one of said mounting plates is provided with locking arms adapted to extend through apertures in the bottom and to engage in locking apertures formed in the other of said mounting plates.

31] Converting set according to one of the clauses 18 - 30, wherein the height of the basket is in the range of 45% to 55% of the length of the upper edge of a said longitudinal wall. 32] Converting set according to one of the clauses 18 - 31 , wherein the length of the transverse wall is, measured at the bottom of the basket, in the range of 90% to 110% of the height of the basket. 33] Converting set according to one of clauses 18 - 32, wherein the length of said upper edge is in the range of 47 cm to 51 cm, such as in the range of 48 cm to 50 cm, preferably about 49 cm.

34] Converting set according to one of the clauses 18 - 33, wherein at least the upper edge of the first transverse wall, preferably the upper edge of each said transverse walls and each said longitudinal walls, is in cross section U shaped; wherein the opening of said U shaped upper edge lies at the outside of the basket and faces downwards; wherein the hinge is mounted against the outside of the outer leg of the U shaped upper edge of the first transverse wall; wherein the hinge has at its upper side a mounting arm having a downwardly facing ridge, the length of the mounting arm being equal to the width of the upper face of said upper edge to provide a locking engagement of the ridge behind the upper edge on the inside of the basket; wherein a snap lip is provided on the lower side of the hinge for snapping engagement with the outer leg of the U shaped upper edge, the snap lip preferably snapping around the lower end of the outer leg.

35] Converting set according to one of claims 18-34, wherein the lengths of the tow bars

17 are fixed.

The invention has been elucidated with reference to the drawings. It will however be clear that further embodiments within the scope of the invention are possible. For example more than four wheel could be provided, the tow bars 17 could be made telescopically so that the length can be adjusted, the tow member 3 could be L-shaped (i.e. leaving away one of the two tow bars 17), etcetera. The scope of this invention will be determined by the scope of the claims as granted on this application.