GB2321223A - Mobile load carrier - Google Patents

Abstract

A mobile load carrier 1 comprises upper 12 and lower 14 open topped receptacles mounted on a wheeled chassis 10 and a supplementary load support (70 fig 4) extendably mounted at the front of the upper receptacle. The load carrier may also include a collapsible child seat 62 provided behind the upper receptacle and an additional load support 64 behind the lower receptacle. The supplementary load support may comprise a load member (74 fig 4) and a front stop member (88 fig 4) and may slide from a retracted position in which the load member is disposed beneath the base of the upper receptacle. The child seat may comprise a bottom support means (106 fig 6) and a back support means 108, the latter of which also forms the rear wall of the upper receptacle. The supplementary load support, child seat and additional load support may all be moved automatically when the carrier is nested with other carriers. A base load tray (180 fig 2) may be mounted on a base part 16 of the chassis beneath the lower receptacle.

Description

MOBILE LOAD CARRIER The invention relates to mobile load carriers and particularly, but not exclusively, to shopping trolleys for use in, for example, supermarkets.

Known shopping trolleys used in supermarkets typically comprise a chassis having wheels fixed at the corner regions thereof, one or more baskets welded or otherwise fixed to the chassis and a push handle fixed to the upper rear end of the trolley.

Conventionally, a single, relatively deep basket has been used in such shopping trolleys. Commonly, the basket has rear gate which can hinge upwardly about a fixed transverse shaft to allow entry of the basket of a similar trolley during stacking. The hinged rear gate commonly has a collapsible child seat formed therewith.

In recent times, it has become common for supermarkets to provide rigid-sided shopping boxes into which the purchased goods can be placed. The idea is that a customer will place one or more such boxes into the trolley before starting shopping, and will load the boxes as he/she proceeds around the supermarket. For example, goods of different general kinds, such as canned goods, fruit and vegetables, washing and cleaning materials, etc. can be placed into different boxes. This system of box shopping is becoming popular and appears to point the way forward for supermarket shopping. It has the advantage over conventional supermarket shopping of facilitating more rapid handling of the goods at checkouts, and safer transport from checkout to the customer's car.

However, it will be appreciated that the abovementioned conventional form of supermarket shopping trolley is not particularly well suited to holding more than one or two such shopping boxes.

A form of shopping trolley has recently become available in which instead of one relatively deep basket, there are provided two, vertically spaced, relatively shallow baskets.

The present invention seeks to develop this concept of the double basket trolley structure, particularly but not exclusively to increase the number of the aforementioned shopping boxes which can be loaded and transported at one time on the trolley.

According to a first aspect of the invention, there is provided a mobile load carrier comprising a wheeled chassis on which are mounted upper and lower open-topped receptacles, the lower receptacle projecting further in the forward travel direction of the mobile load carrier than the upper receptacle, the mobile load carrier further comprising a supplementary load support mounted on the upper receptacle so as to be selectively extendable in a forward direction relative to the front of said upper receptacle thereby to provide for load support forwardly of said front of the upper receptacle.

In a further aspect, the present invention aims to provide a double receptacle mobile load carrier with a collapsible child seat providing minimum reduction in the capacity of the upper receptacle.

According to this aspect, there is provided a mobile load carrier comprising a wheeled chassis having upper and lower open-topped receptacles mounted thereon and a collapsible child seat provided behind the rear end of the upper receptacle, said child seat having bottom support means and back support means, said back support means also forming a rear wall of said upper receptacle.

Preferably, said child seat is arranged to fold forwardly and upwardly so as to permit the forward end of the upper receptacle of a similar mobile load carrier to enter through the rear of said upper receptacle during nesting of said carriers.

The child seat preferably comprises a further member pivotally suspended from a transverse shaft fixed forwardly of a transverse handle of the carrier, and providing apertures through which the legs of a child seated on the bottom support means will pass.

The bottom support means may include a base support, and a flat seat panel pivotable between a horizontal position overlying said base support and an upright position closing said apertures. This enables the child seat to be selectively usable as an additional goods receptacle.

Preferably, additional wall means are fixed to an upper rear part of the chassis so as to effectively close off gaps at the sides of the child seat. This improves the load-carrying function of the child seat.

In a further aspect, the present invention aims to provide additional load capacity at a position immediately behind the lower receptacle in a double receptacle mobile load carrier. In this aspect, there is provided a mobile load carrier comprising a wheeled chassis, upper and lower open-topped receptacles mounted on said chassis, said lower receptacle having a generally upright rear wall, and an additional load support mounted on said chassis behind said rear wall of said lower receptacle.

Preferably, the rear wall of the lower receptacle is mounted so as to pivot upwardly to permit the front end of the lower receptacle of a similar load carrier to pass into the lower receptacle for nesting purposes. The additional load support may have a pivoted rear wall which is pivoted forwardly by engagement with said lower receptacle of the further, similar mobile load carrier during nesting.

In each aspect of the invention, the mobile load carrier may further comprise a base tray, mounted on a base part of the chassis beneath the lower receptacle, for additional load storage.

In order that the different aspects of the invention may be well understood, an embodiment thereof, which is given by way of example only will now be described with reference to the accompanying drawings, in which: Fig. 1 is a side elevation of a mobile load carrier embodying each of the aspects of the invention; Fig. 2 is a front perspective view of the mobile load carrier; Fig. 3 is a top, front perspective view of the upper basket of the mobile load carrier, showing a supplementary load support in an extended position; Fig. 4 is a side elevational view of the front part of the upper basket of the mobile load carrier shown in Fig. 3, showing the supplementary load support in its extended position; Fig. 5 is a longitudinal sectional view of part of the sliding mounting arrangement for the supplementary load support shown in Figs. 3 and 4; Fig. 6 is a perspective view from the rear and one side showing the construction of a child seat provided on the mobile load carrier, shown in the use position thereof; Fig. 7 is a side perspective view showing the child seat of Fig. 6 in a partly folded-up position thereof; Fig. 8 is a rear perspective view of a lower, rear part of the mobile load carrier, showing the construction of an additional load support basket, mounted behind the lower main basket.

Referring to Figs. 1 and 2 a mobile load carrier in the form of a shopping trolley 1 comprises a wheeled chassis 10, having upper and lower load receptacles 12, 14 mounted thereon. The chassis 10 is shown with two such load receptacles, each in the form of an open-topped basket, which may be of wire mesh construction, mounted thereon.

The chassis 10 comprises a base part 16 and a rear upright support part 18 to which the baskets 12 and 14 are mounted. The base part 16 comprises two base members 20 which extend in the lengthwise direction of the trolley 1. The construction of the base part 16 can best be understood from Fig. 2, in which it can be seen that the two base members 20 are arranged in lateral spaced apart relationship and are interconnected by a first cross-member 22 disposed at the leading end of the trolley and a second crossmember 24 disposed towards the rear end of the trolley. The second cross-member 24 extends between and is fixed at its opposite ends to the inwardly facing surfaces of respective web plates 26 joined by means of welding to the tops of the respective base members 20 at the rear ends thereof.

The rear upright part 18 of the chassis comprises two curved side members 30 arranged so as to be generally upright and forwardly bowed, and joined by means of welding both to the rear end of a respective one of the base members 20 and to a rear, upwardly and forwardly curved edge 32 of the corresponding web plate 26. Accordingly, each web plate 26 interconnects a respective one of the base members 20 and the corresponding side member 30 in the region at which those members are joined to each other, and serves to strengthen the joint between the two members.

The base members 20, side members 30 and the first cross-member 22 are made from oval-section tubing, arranged with its flat faces in vertical planes.

A respective one of a set of castors 34 is fixed to the leading end of each base member 20 and the lowermost end of each side member 30.

The uppermost end of each side member 30 is bent so as to curve rearwardly and downwardly, and a handle support bracket 38 is fitted to the lower end of the downwardly bent end portion of the respective end member; a push handle 39 which extends transversely of the trolley extends between the support brackets 38.

As a result of the two-level basket structure of the trolley its overall height is somewhat greater than that of a conventional single-basket trolley.

This handle structure has the advantages of compensating for this added height and placing the push handle at convenient and comfortable level.

Each of the upper and lower baskets 12, 14 comprises a generally U-shaped rear support bracket 40, 40' respectively, by which the basket is fixed to the rear upright part 18, and a relatively shallow, forwardly projecting wire mesh basket member 42, 42' joined by welding to the support bracket 40, 40'. Each said support bracket 40, 40' is formed from a single piece of heavy gauge wire and comprises two side arms 44, 44' each extending along the front of an arcuate portion of the respective side member 30, and a lower cross-piece 46, 46' extending horizontally between said side members 30. Joined by welding to each of the side arms 44, 44' is a pair of fixing plates 48, 48', best seen in Figure 6, riveted or otherwise joined to an inner face of the respective side member 30.

Each U-shaped basket support bracket 40, 40' defines a rear opening into the respective upper or lower basket, which opening is, during use of the trolley, closed by means of a respective rear end gate, to be described in further detail later herein.

The forwardly projecting basket member 42, 42' for each of the upper and lower baskets comprises a generally U-shaped upper basket rim member 52, 52' defining the upper edge of the basket, including curved front corners thereof, and comprising a pair of correspondingly U-shaped wire elements (not shown) joined by welding one on top of the other. A further U-shaped single wire element forms a forwardly projecting lower basket former 54, 54'. The lower basket, 14, being somewhat deeper than the upper basket 12, has a pair of vertically spaced such formers 54'. The side arms of the members 52, 52' and 54, 54' extend along the side walls of the respective basket, and the forward end portions of these members extend widthwise of the trolley across the front of the basket. In each basket, a multiplicity of relatively narrow gauge wire elements 56 constitute a wire mesh and are joined by welding to the side arms and forward end portions of the U-shaped members 52, 52' and 54, 54' to form the basket base and the side and front basket walls.

Each of the upper and lower baskets includes a protective plastics extrusion 60 which is fitted onto and extends continuously around the upper rim of the basket formed by the U-shaped member 52, 52'. The plastics extrusion has a generally figure-of-eight internal cross-section configuration so as to fit closely onto the double-wire form of the U-shaped member 52, 52'. The upper wire of this member 52, 52' is completely covered by an upper portion of the plastics extrusion, while an inwardly facing portion of the lower wire of the member 52, 52', to which the upper ends of the basket-forming elements 56 are welded, is exposed. Securing clips 61 encircle the plastics extrusion at or adjacent the rear ends of the each U-shaped member 52, 52' so as to hold the extrusion securely in place.

A hinged, collapsible child seat 62 is provided behind the rear end of the upper basket 12, and an additional load support 64 is attached to, and extends between the side members 30 so as to be positioned behind the lower basket 14.

To afford adequate access to the interior of the lower basket 14, the upper basket 12 is shorter in the longitudinal direction of the trolley than the lower basket. Accordingly, since the front end of the upper basket 12 lies rearwardly of the front end of the lower basket 14, access to both the front and rear parts of the lower basket 14 for loading and unloading is facilitated. In particular, this arrangement makes it possible to place a rigid walled shopping box B, shown in broken lines in Figure 1, of a height greater than the vertical space between the upper rim of the lower basket and the base of the upper basket into the front of the lower basket and then slide it rearwardly to a position beneath the upper basket, leaving space at the front of the lower basket for a further such shopping box B. Another such shopping box can be accommodated in the upper basket.

To increase the load capacity of the trolley even further, a longitudinally slidable supplementary load support 70 is provided at the front portion of the upper basket 12.

This supplementary load support 70, best shown in Figures 3 to 5, comprises a sliding support member 72 integrally formed from a single piece of heavy gauge metal rod; this support member 72 includes two parallel longitudinally extending slide rods 74 and an inverted U-shaped, upwardly projecting front portion 75 comprising side arms 76 and a top cross piece 78.

Each of the slide rods 74 is slidingly received within a respective slide support 80 fixed to the underside of the base of the upper basket 12.

The construction of each slide support 80 in the preferred embodiment is illustrated in Fig. 5, and its position of mounting is illustrated in Figs. 3 and 4.

As shown in these Figures, each said slide support comprises a tube 82, preferably of metal, which is fixed by means of welding to the outside of a respective one of two longitudinally extending wire strengthening rods fixed to the underside of the base of the upper basket 12. Each said wire rod is Lshaped, and has a relatively long limb joined by welding at its rear end to the underside of the crossmember 46, 46' of the U-shaped support bracket 40, 40', and an upwardly directed short front limb 84 welded at its upper end to the basket former 54.

Smooth sliding of the slide rods 74 within the respective tubes 82 is facilitated by means of plastics cylindrical bushes 86 fixed within the opposite ends of each of the slide tubes 82. A transverse load stop 88 fixed behind the front portion 75 includes side stops 90 for restraining a load placed on the supplementary load support 70 in a lateral direction. Between the slide rods 74 there is provided a pair of additional load support rods 92 which are formed at their rear end integrally with an upwardly open, U-shaped, downwardly extending engagement member 94. At their forward ends, these rods 92 are bent so as to extend upwardly between, and parallel to the side arms 76 of the U-shaped member 75. These upwardly extending portions 96 at the front ends of the support rods 92 are joined by welding to the top cross-piece 78 of the front portion 75 of the sliding support member 72.

The function of the engagement member 94 is to provide automatic retraction of the supplementary load support 70 during nesting into another, similar trolley from behind, in the event that this support 70 on the rear trolley being nested is in its extended position. When this happens, the engagement member 94 will engage the lower cross-piece 46 of the upper basket rear support bracket 40 of the forward trolley, whereupon further nesting will automatically bring about retraction of the supplementary load support 70 of the rear trolley. At the end of this automatic retraction, the side stops 90 each pass through a gap between a respective pair of the upright portions of a pair of the wire elements 56 forming the rounded front corners of the upper basket 12; this can best be seen at X in Figure 2.

When fully extended, the supplementary load support 70 provides a sufficiently large additional load support surface for another shopping box B to be carried in front of the front wall of the upper basket 12, as illustrated in broken lines in Figure 4.

The collapsible child seat 62, provided behind the upper basket, is best seen in Figures 1, 3, 6 and 7. The seat 62 is suspended from a transverse shaft 102 which is fixed by welding to the rear of the side members 30 at upper portions thereof close to the positions where they curve rearwardly and downwardly toward the push handle 39. The child seat comprises a rear pivotal member 104 suspended from the shaft 102, a bottom support member 106 pivoted to a lower portion of the rear member 104, and a back support member 108 pivoted to a forward portion of the bottom support part 106.

The rear member 104 is of wire rod construction and comprises a U-shaped frame member 110 having two side arms 112 and a horizontal base bar 114. The top ends of the side arms 112 are bent forwardly to form pivot hooks 116 by which the rear member 104 is pivotally suspended from the transverse shaft 102.

Upper and lower intermediate cross-bars 118, 120 are each welded at their opposite ends to the rear and front, respectively, of the side arms 112. The lower intermediate cross-bar 120 is disposed just above the level of the base bar 114.

The rear member 104 further includes a pair of restraint members 124 welded to and spanning between the upper intermediate cross bar 118 and the base bar 114. Each of these restraint members 124 is intended to fit between the legs of a child sat on the bottom support member 106 so as to prevent the child from slipping rearwardly through the gap formed beneath the upper intermediate cross member 118. It should be noted that although in this embodiment the child seat is adapted to accommodate two children sitting sideby-side, a simple modification, involving the use of only one restraint member 124 will change the seat into one for a single child. The restraint members 124 thus define apertures in the rear member 104, through which the legs of a child, or children, sat on the bottom support part 106 will pass.

The rear pivotal member 104 can swing forwardly from its position illustrated in Figures 1 and 6, but rearward pivoting from this generally vertical position is prevented by a pair of stops 126 formed by downwardly and inwardly bent end portions of the transverse shaft 102. By this means, the child seat 62 normally remains safely stable in its use position, and cannot swing rearwardly from this position. This stability is of particular benefit when placing the child or children onto the seat.

The bottom support member 106 includes a plurality (in this case two) of longitudinally extending pivot rods 130 pivoted at their rear ends to the lower intermediate cross-bar 120 and at their forward ends to a lower portion of the back support 108, and a set of parallel, transverse, regularly spaced base support rods 132 welded at their opposite ends to the undersides of the pivot rods 130 and forming therewith a base support. There is also provided a pair (or one in the aforesaid modification for single child support) of flat plastics seat panels 134 each pivoted along its rear edge to the lower intermediate cross-bar 120. In its lower position, the or each such seat panel 134 lies on the base support to form a flat seat surface. In its raised position (illustrated for one such panel in Figure 7) lying flat against the forward side of the rear member 104 it covers the leg apertures provided in the rear member 104 so as to form a closed storage space in the child seat. Thus, with one or both seat panels in the raised position, the seat, in its use position, shown in Figure 6, provides a convenient space, additional to that provided by the baskets, for load carrying.

The back support member 108 is also of wire mesh construction and comprises a rectangular frame member 136, upper and lower intermediate cross-bars 138, 140, each welded at their opposite ends to respective side elements of the frame member 136, and a number of upright rods 142 fixed to and spanning between upper and lower horizontal elements of the frame member 136 to form a back rest surface.

The upper and lower intermediate cross-bars 138, 140 of the back support 108 are at substantially the same vertical levels as, respectively, the upper and lower intermediate cross-bars 118, 120 of the rear pivotal member 104. The side pivot rods 130 are pivoted at their forward ends to the respective ends of the lower intermediate cross-bar 140, and a pair of upper pivot rods 146, of substantially the same length of the lower pivot rods 130, are pivotally connected, and extend longitudinally between the corresponding ends of the upper intermediate cross-bars 118, 138 of the rear pivotal member 104 and the back support member 108, so as to form a pivotal link between the upper portions of such rear pivotal and back support members 104, 108.

The back support member 108 is further provided with a pair of laterally projecting engagement elements 148 which engage the upper edges of the respective side portions of the upper basket rim member 52. In the illustrated embodiment, these engagement members 148 are formed as L-shaped hooks which project downwardly outside the upper basket rim.

The back support member 108, in the normal position of the child seat as illustrated in Figures 1, 3 and 6, also forms the rear wall of the upper basket 12.

Since the child seat is thus located generally behind and outside the space within the basket 12, it does not reduce the amount of space available in the basket 12 for load carrying.

During trolley nesting, the front end 12' of the upper basket 12 of a rear trolley (not shown) which is being pushed forwardly to nest with the illustrated trolley engages the rear pivotal member 104 and pushes it forwardly. This movement is a forward, upward pivotal movement about the shaft 102, and the forward movement of the lower end of the rear pivotal member 104 causes a three-lever folding action, as illustrated in Figure 7, so that the elements constituting the child seat collapse, with the back support and rear pivotal members remaining generally parallel to each other, as the rear trolley is pushed further into the forward trolley. Eventually, the child seat collapses into a generally flat configuration, with the back support member 108 lying flat on top of the bottom support member 106.

On de-nesting of the trolley, as the forward and rear trolleys are separated, the child seat will unfold under the effect of gravity, again by a threelever action, until the seat resumes its in-use position, in which the lower horizontal element of the frame member 136 of the back support member engages against the lower cross-piece 46 of the U-shaped rear support bracket 40 of the upper basket 12, and the side arms 112 of the rear pivotal member 104 engage against the stops 126. In the early stages of this unfolding process, the engagement members 148, which had been lifted above the level of the upper basket rim 52, descend into engagement with such rim. This prevents the child seat from descending in its folded, collapsed state into engagement with the floor of the upper basket, and facilitates a smooth automatic movement to the in-use position, during which the back support member 108 generally pivots downwardly and rearwardly under gravity about the positions of engagement between the engagement members 148 and the upper basket rim.

As mentioned previously, the child seat in its use position, can be used for load carrying. The upwardly hinged seat panels 134 prevent items falling rearwardly out of the additional storage space through the leg apertures. A pair of generally triangular wire mesh side walls 150 are each welded or otherwise fixed to the rear edges of the respective side members 30 immediately behind and at the same height as the upper basket 12. As can best be seen in Figures 3 and 6, these side walls 150 each close off a generally triangular gap which would otherwise be formed at the sides of the child seat, thus preventing goods from falling out of the sides of the additional storage space when the child seat is used for load carrying.

With reference to Figures 1 and 8, the lower basket 14 includes a rear gate 154 which is pivotally suspended from a further transverse shaft 156, again for nesting purposes. That is to say, during trolley nesting, the forward end of the lower basket 14 of a rear trolley (not shown) engages the rear of this gate 154 and pushes it forwardly and upwardly. The lower basket 14 of the rear trolley can then enter the lower basket of the illustrated trolley. In the illustrated embodiment of the invention, there is provided an additional load support 64 which is fixed to the side members 30 so as to be positioned behind the lower basket 14. The additional receptacle 64 comprises a downwardly and rearwardly inclined base 162 attached to and projecting rearwardly from the lower crosspiece 46' of the U-shaped rear support bracket 40' of the lower basket 14. The lower rear end of the base 162 is bent upwardly so as to provide a retaining stop 164 for goods placed on the base 162. A pair of wire mesh side walls 166 fixed to the side members 30 by fixing plates 168 provide further containment for the goods carried in the additional receptacle 160. The lower rear end of the base 162 is fixed at opposite sides to and supported by lower rear portions of the side members 166.

The support 64 is preferably also provided with an elongate laterally extending rear wall 170 which at its opposite ends is pivotally attached at pivot points 172 to the lower rear portions of the side walls 166. In its pivotally rearmost position, this rear wall 170 engages the top of the rear upwardly bent portion 164 of the base 162. As shown in Figure 8, this rear wall 170 provides added secure retention for a large load, such as an additional shopping box placed on the rear support 64. During trolley nesting, the underside of the lower basket 14 of the rear nesting trolley will engage the top edge of this rear wall 170, causing it to pivot forwardly to allow maximum nesting. The wall 170 is sprung by means of coil spring 174 mounted at the pivot points 172 of the wall 170 to one or both of the side walls 166 so as to be biased to the rearward position. Forward pivoting of the rear wall 170 during nesting thus occurs against the spring bias.

With reference to Figure 2, disposed between the base members 20 is a base tray 180 comprising a plurality of longitudinally extending wire rods 182 bent upwardly adjacent their rear ends 184. The laterally outermost rods 182 are bent so as to form support hooks 186 which hook over the second crossmember 24. The base tray 180 is supported at its front end over the first cross-member 22.

The base tray 180 is mounted so that it can pivot upwardly about the first cross-member 22 from a lower position, illustrated in Figure 2, in which the space above the tray 180 and beneath the base of the lower basket 114 is maximised, so as to provide as much space as possible for bulky items, such as further shopping boxes B. The tray 180 pivots upwardly during trolley nesting, so as to permit the base part 16 of the chassis of a rear trolley (not shown) to enter the space between the base members 20 of the illustrated trolley.

It will be appreciated from the above description and from the illustration in the accompanying Figures, that the construction of the trolley according to aforesaid different aspects of the invention affords maximum loading capacity, and in particular, enables the maximum number of shopping boxes B to be transported on the trolley. In the illustrated embodiment, in which the different aspects are used in combination, seven such shopping boxes can be accommodated, two on the base shelf 180, two in the lower basket 14, one in the upper basket 12, one on the additional support 64 provided behind the rear gate 154 of the lower basket, and one on the supplementary load support 88 when extended from the front of the upper basket 12. Moreover, even when so loaded with seven shopping boxes B, the space within the child seat provides additional loading capacity for loose items of shopping.

It will be understood that any combination of two or more of the different aspects may be employed to advantage.

Claims (26)

1. A mobile load carrier comprising a wheeled chassis on which are mounted upper and lower opentopped receptacles, the lower receptacle projecting further in the forward travel direction of the mobile load carrier than the upper receptacle, the mobile load carrier further comprising a supplementary load support mounted on the upper receptacle so as to be selectively extendable in a forward direction relative to the front of said upper receptacle thereby to provide for load support forwardly of said front of the upper receptacle.

2. A mobile load carrier according to claim 1, wherein said supplementary load support is arranged to slide in said forward direction from a retracted position.

3. A mobile load carrier according to claim 2, wherein said supplementary load support comprises a load member for receiving a load placed thereon, said load member being disposed beneath the base of said upper receptacle in said retracted position.

4. A mobile load carrier according to claim 3, wherein said load member comprises a plurality of elongate parallel slide elements, said slide elements being slidably engaged with respective slide support elements mounted on the underside of said upper receptacle.

5. A mobile load carrier according to claim 4, wherein said slide elements each comprise a rod and said slide support elements each comprise a tube through which the corresponding rod extends coaxially.

6. A mobile load carrier according to claim 5, wherein said rods are metallic and wherein said tubes each include an elongate tubular element and slide bushes fitted in opposite ends thereof and in sliding engagement with the outer surface of the respective rod.

7. A mobile load carrier according to any of claims 3 to 5, wherein said supplementary load support further comprises an upwardly projecting front stop member for retaining said load on said load member.

8. A mobile load carrier according to claim 7 when dependent on any of claims 4 to 6, wherein said front stop member includes a plurality of upwardly extending elements, each integrally formed with a respective one of said slide elements.

9. A mobile load carrier according to any preceding claim, wherein said supplementary load support includes an engagement member so adapted that when the trolley is being nested forwardly into a similar trolley with said supplementary load carrier forwardly extended, said engagement member engages part of the similar, forward trolley, and is automatically moved rearwardly towards a or the retracted position thereof.

10. A mobile load carrier according to any preceding claim, wherein in a or the retracted position of said supplementary load carrier it provides substantially no load support forwardly of said front of the upper receptacle.

11. A mobile load carrier comprising a wheeled chassis having upper and lower open-topped receptacles mounted thereon and a collapsible child seat provided behind the rear end of the upper receptacle, said child seat having bottom support means and back support means, said back support means also forming a rear wall of said upper receptacle.

12. A mobile load carrier according to claim 11, wherein said child seat is arranged to fold forwardly and upwardly so as to permit the forward end of the upper receptacle of a similar mobile load carrier to enter through the rear of said upper receptacle during nesting of said mobile load carriers.

13. A mobile load carrier according to claim 12, wherein said child seat comprises a further member pivotally suspended from a transverse shaft fixed forwardly of a transverse handle of the carrier, and providing apertures through which the legs of a child seated on the bottom support means will pass.

14. A mobile load carrier according to claim 13, wherein the bottom support means includes a base support and a flat panel pivotable between a horizontal position overlying said base support and an upright position closing said apertures.

15. A mobile load carrier according to any of claims 11 to 14, wherein said chassis includes a base part and a rear generally upright part on which said receptacles are mounted and from which they project forwardly, and wherein additional wall means are fixed to an upper rear part of said upright part of the chassis so as to close off gaps at the sides of the child seat.

16. A mobile load carrier according to any of claims 13 to 15, wherein said bottom support is pivotally connected at a rear edge thereof to a lower portion of said further member and at a forward edge thereof to a lower portion of said back support means.

17. A mobile load carrier according to claim 16, wherein said back support means extends between rear side portions of an upper receptacle top rim, and includes laterally projecting engagement means for bearing on said top rim so as to control the movement of the child seat as it unfolds from its forwardly and upwardly folded position when said upper receptacle of said similar mobile load carrier exits through said rear of said upper receptacle during denesting of said mobile load carriers.

18. A mobile load carrier according to claim 16 or claim 17, wherein the child seat further includes pivotal link means extending between and pivotally connected to an upper portion of said further member and an upper portion of said back support means, whereby forward and upward pivoting of said further member during nesting causes a corresponding forward and upward pivoting of said back support means, so as to effect the folding of the child seat.

19. A mobile load carrier comprising a wheeled chassis, upper and lower open-topped receptacles mounted on said chassis, said lower receptacle having a generally upright rear wall, and an additional load support mounted on said chassis behind said rear wall of said lower receptacle.

20. A mobile load carrier according to claim 19, wherein the rear wall of the lower receptacle is mounted so as to pivot upwardly to permit the front end of the lower receptacle of a similar load carrier to pass into the lower receptacle for nesting purposes.

21. A mobile load carrier according to claim 20, wherein the additional load support has a rear wall which is mounted so as to pivot forwardly by engagement with said front end of the lower receptacle of the further, similar mobile load carrier during nesting.

22. A mobile load carrier according to claim 21, wherein spring bias means is provided for biasing said rear wall of said load support in a rearward pivotal direction.

23. A mobile load carrier according to any of claims 20 to 22, wherein said additional load support comprises a base support member which is fixedly mounted on said chassis.

24. A mobile load carrier according to any preceding claim, wherein a base load tray is mounted on a or the base part of the chassis beneath the lower one of said upper and lower receptacles, for further load carrying.

25. A mobile load carrier according to any preceding claim, wherein at least one of said upper and lower receptacles has an upper rim which is curved at the front corners of the receptacle and a protective cover strip fitted over and extending continuously around said upper rim.

26. A mobile load carrier substantially as hereinbefore described with reference to the accompanying drawings.