FR3024393A1 - ROLLING UNIT, MOBILE ELEMENT COMPRISING SAME AND ALL OF MOBILE ELEMENTS - Google Patents

Abstract

The rolling unit comprises an orientation locking device configured so that the wheel (80), as it rotates in a first direction (A ') or in a second direction, is respectively fixed orientation or free orientation . The orientation locking device has two teeth (81) for the rolling unit (25) to have an orientation locking configuration in which the wheel (80) is between the teeth (81); and a free orientation configuration in which the wheel (80) is not located between the teeth (81); each tooth (81) being configured to tilt to a release position where the wheel (80) is no longer between the teeth (81) and can move freely. The movable element (4) comprises at least one wheel (80) which is part of such a rolling unit (25). The assembly comprises several movable elements (4, 5, 16) each connected to a neighboring mobile element by a hitch.

Description

The invention relates to mobile elements which comprise at least one wheel, for example wheelbarrows, industrial trucks, supermarket trolleys or pushchairs. Such movable elements are known from which a wheel is part of a rolling unit comprising: a support configured to be arranged in a predetermined direction of movement; a wheel having a hub, configured to roll with the hub which is oriented parallel to the ground on which the wheel rests; a member for holding the wheel by its hub; and - a pivotally mounting bearing of the holding member on the support, configured to be oriented transversely to the ground, the bearing and the hub being offset relative to each other, that is to say say that the bearing is not in line with the hub.

Because of the offset, there is a lever arm between the bearing and the contact point on the ground of the wheel. Therefore, if the wheel is left free to pivot around the bearing, it spontaneously takes the orientation that offers the least resistance to the displacement forces exerted on the rolling unit, and more generally on the movable member of which is part of the rolling unit. Such freedom of orientation of the wheel is appreciated because it allows to have movable elements particularly manageable, in all directions. However, when a movable element has all its wheels which are free of orientation, its displacement over long distances can become tiring for the operator who moves it since he must control the trajectory in all directions. In order to overcome this disadvantage, there are movable elements of which some wheels are fixed orientation and the other wheels have a mobile orientation.

It is understood that in this specification the orientation of a wheel should be understood as the orientation of its general plane.

It has already been proposed, in particular by the French patent application 2,653,070 and by the international application PCT WO 2005/105539, rolling units which comprise an orientation locking device of the wheel holding member so that the latter, as it rotates in one direction or the other, is respectively fixed orientation in the direction of travel provided for the rolling unit or is free orientation. The invention aims, in a first aspect, to provide a similar rolling unit, but simpler, more convenient and more economical. The invention proposes for this purpose a rolling unit comprising: a support configured to be arranged in a predetermined direction of movement; a wheel having a hub, configured to roll on a floor with the hub which is oriented parallel to said floor; a member for holding said wheel by its hub; - A pivotally mounting bearing of the holding member on the support, configured to be oriented transversely to said ground, the bearing and the hub being offset relative to each other; and a wheel orientation blocking device, configured so that the wheel, as it rotates in a first direction or a second direction, is respectively fixed orientation in said direction of displacement or free orientation; characterized in that said wheel orientation lock device comprises two teeth mounted on the tilt support along said direction of travel, said teeth taking a predetermined home position in the absence of bias; said wheel, said holding member and said teeth being configured so that the rolling unit has: - a wheel orientation locking configuration in said direction of travel, in which the teeth are in the rest position and the wheel is between the teeth; and a configuration of free orientation of the wheel, in which the wheel is not located between the teeth; each tooth being configured to tilt, from the rest position while the rolling unit is in the orientation lock configuration, away from the holding member to a release position where the wheel no longer between the teeth and can move freely.

In the rolling unit according to the invention, the teeth act directly between the wheel and the support on which the wheel holding member is pivotally mounted, unlike the previous rolling units where the locking device acts between the wheel and the wheel. holding member of the wheel and the support.

It will be observed in particular that in the rolling unit according to the invention, the teeth are mounted on the support and not on the wheel holding member; and that the teeth block the pivoting of the wheel vis-a-vis the support directly and not through the wheel holding member.

The rolling unit according to the invention thus avoids the mounting constraints of the locking device on the wheel holding member, which are fairly consistent especially in terms of space. The rolling unit according to the invention can thus be implemented with relatively few constraints and therefore simply, conveniently and economically. In addition, because of the lack of direct intervention on the wheel holding member, the rolling unit according to the invention can be manufactured from a commercial rolling unit where the wheel is free orientation, adding the locking device on a common support. According to advantageous features of implementation of the rolling unit according to the invention: - said wheel and said teeth are configured so that the passage between one and the other of the configuration of locking orientation and the free orientation configuration is effected automatically by direct interaction between the wheel and the teeth; the teeth swing from the rest position to the release position by rotating in the same direction as the first direction of rotation of the wheel, and said direct interaction between the wheel and the teeth is such that when the wheel is between the teeth and rotates, in contact with a tooth the wheel urges the tooth to tilt by turning in the opposite direction of the wheel; - the teeth rigidly associated with each other; - The teeth are part of a fork having a cross member which project teeth, said cross member being mounted to tilt on said support and oriented transversely to the direction of movement; and / or - the teeth extend over the entire thickness of a rolling lining that includes the wheel.

The invention also aims, in a second aspect, a movable member having at least one wheel, characterized in that said wheel is part of a rolling unit as explained above. According to advantageous features of implementation of such a movable element, the latter extends in a predetermined direction of movement between a first side and a second side, with a first side of a first pair of freely steerable wheels and the second side side a second pair of wheels each of which is part of a rolling unit as explained above, which rolling units have their direction of movement which corresponds to the direction of movement of the movable member and have their wheel which rotates in the first direction when the movable member is moved in a first direction from the second side to the first side and their wheel rotates in the second direction when the movable member is moved in a second direction from the first side to the second side side, whereby the movable element has a different ground relationship depending on whether it is moved in the first direction or in the second ns: in the first direction, the movable element has a nominal ground relation in which the wheels of the first pair are freely steerable and the wheels of the second pair are kept oriented in the direction of movement, and in the second direction, the mobile element has this nominal ground relation except that the wheels of the second pair are freely adjustable.

The invention also aims, in a third aspect, an assembly comprising a plurality of movable elements as explained above, with each movable element which is connected to a neighboring mobile element by a hitch. According to advantageous features of implementation of this assembly, each said hitch comprises a hook and a drawbar movable to slide relative to each other so that the hitch admits an extended position in which the sides turned one to the other connected movable elements are moved away from each other and so that the hitch has a retracted position in which the sides facing each other are close together.

The description of the invention will now be continued by the detailed description of exemplary embodiments, given below by way of illustration and without limitation, with reference to the appended drawings. On these: - Figure 1 is a perspective view showing the underside of a carriage having four rolling units including two rolling units according to the invention; - Figure 2 is a partial perspective view of the carriage, taken at another angle, showing a portion of the carriage comprising one of the rolling units according to the invention; FIGS. 3 and 4 are views similar to FIG. 2, but whereas the rolling unit is in the wheel orientation locking configuration in FIG. 2, the rolling unit is in the orientation configuration free of the wheel in Figure 3 and in an intermediate configuration in Figure 4; - Figure 5 is a schematic plan view of a warehouse in which two operators prepare orders, one pulling the carriage shown in Figure 1, the other pushing the carriage; - Figure 6 is an elevational view of an assembly comprising the carriage shown in Figure 1 and an identical carriage, coupled to one another, with the coupling connecting the two carriages which is in the deployed position; - Figure 7 is a view similar to Figure 6, but with the hitch in the retracted position; - Figure 8 is a view similar to Figure 5, but with the operators moving the set of two carriages shown in Figures 6 and 7; and FIG. 9 is a view similar to FIG. 8, but with trolley assemblies which comprise an additional trolley. The carriage 4 illustrated in FIG. 1 extends in a direction of displacement 14 between a first side 40, located on the left in FIG. 1, and a second side 41, located on the right in FIG. 1. The carriage 4 comprises a chassis 42 globally tray-shaped, here made of lattices of welded metal rods at their intersections. The carriage 4 comprises a drawbar 62 positioned on the first side 40 and a hook 61 positioned on the second side 41. As can be seen in FIG. 1, the drawbar 62 has a longitudinal slot 65.

As seen in Figures 6 and 7, as will be described in more detail later, the slot 65 is configured to receive the hook 61 of another carriage and to allow it to slide there. The carriage 4 comprises, on the first side 40, a first pair 7 of wheels 70 and, on the second side 41, a second pair 8 of wheels 80.

Each pair 7 and 8 comprises a wheel near a lateral side of the carriage 4 and a wheel near the other lateral side of the carriage 4. It is recalled here that in the present specification, the orientation of a wheel must be understood as the orientation of its general plan. The wheels 70 are freely steerable, whatever the conditions of movement of the carriage 4. On the other hand, the ground relation of the wheels 80 is different depending on whether the carriage 4 is moved in the direction of towing from the second side 41 towards the first 40 side or moved in the direction of pushing from the first side 40 to the second side 41.

When the carriage 4 is moved in the direction of tow (second side 41 to first side 40), the wheels 80 are fixed orientation, in this case maintained oriented in the direction of movement 14.

When the carriage 4 is moved in the pushing direction (first side 40 to second side 41), the wheels 80 are freely steerable. Each wheel 80 is part of a rolling unit 25 which will now be described in support of Figures 2 to 4.

As can be seen more particularly in FIG. 2, the rolling unit 25 comprises, in addition to the wheel 80, a support 50 and a member 60 for holding the wheel 80 by its hub 75, the member 60 being mounted pivoting on the support 50. The support 50 is configured to be arranged in a predetermined direction of movement, which of course corresponds here to the direction of movement 14 of the carriage 3. The support 50 extends in the direction of movement 14 between a first side 51 and a second side 52. The first side 51 of the support 50 is turned towards the first side 40 of the carriage 4. The second side 52 of the support 50 is turned towards the second side 41 of the carriage 4. In a transverse direction to the direction of movement 14, the support 50 extends between a first lateral side 54 and a second lateral side 55. The first lateral side 54 and the second lateral side 55 each extend between one end of the first first side 51 and one end of the second side 52. Here, the support 50 is made of metal and comprises a generally rectangular plate 48 and tabs 53, 56 and 57 which project transversely to the plate 48, to the side where is located the wheel 80, respectively from the second side 52, from the first lateral side 54 and from the second lateral side 55. The hub 75 is conventionally designed to be oriented parallel to the ground S (FIGS. 6 and 7) on which the carriage 4 is resting that is to say in principle in a horizontal direction. The wheel 80 therefore extends in a general plane transverse to the ground S, that is to say in principle in a vertical plane. The member 60 here includes two legs 77 located on either side of the wheel 80 and each fixed to the hub 75. The member 60 further comprises a flange 78 disposed between the two legs 77. Here, the member 60 further comprises a reinforcing member 76, connecting the two legs 77 to each other in addition to the flange 78 to provide more rigidity and strength. The pivotal mounting of the member 60 on the support 50 is carried out by means of a bearing 79 (FIG. 4) disposed in the center of the flange 78. The bearing 79 is oriented transversely to the ground S, that is to say in principle in a vertical direction. The bearing 79 and the hub 75 are offset relative to each other, that is to say that the bearing 79 is not in line with the hub 75. There is therefore a lever arm between the bearing 79 and the contact point on the ground of the wheel 80. Therefore, if the wheel 80 is left free to pivot around the bearing 79, it spontaneously takes the orientation which offers the least resistance to the displacement forces. exerting on the rolling unit 25, and thus on the carriage 4 to which the rolling unit 25 is fixed.

Thus, the wheel 80 is oriented as shown in Figure 2 when the carriage 4 is moved in the direction of towing, shown by the arrow A in Figure 2, from the second side 41 to the first side 40; and it is oriented as shown in FIG. 3 when the carriage 4 is moved in the pushing direction, shown by the arrow B in FIG. 3, going from the first side 40 to the second side 41. In order to allow the wheel 80 to be selectively fixed orientation or free orientation, the rolling unit 25 further comprises a wheel orientation locking member 80, which is here formed by a fork 45. The fork 45 has two teeth 81 and a cross-member 82. The teeth 81 project from the cross-member 82 while being parallel to one another. The distance between the two teeth 81 is slightly greater than the width of the wheel 80. The two teeth 81 here have a rod shape. Similarly, the cross member 82 here has a rod shape.

The fork 45 is pivotally mounted relative to the support 50 by the cross member 82, which is oriented in a direction transverse to the direction of movement 14.

The tilting assembly of the fork 45 on the support 50 takes place thanks to the tabs 56 and 57, which are located on the support 50 between the bearing 79 and the second side 52. Therefore, the fork 45 is located on the support 50 between the bearing 79 and the second side 52.

The fork 45 is centered relative to the support 50 in the direction of the cross member 82, that is to say in a direction transverse to the direction of displacement 14. As the bearing 79 is also centered with respect to the support 50 following a direction transverse to the direction of movement 14, regardless of the angular position of the fork 45, a line centered on the bearing 79 and on the two teeth 81 is oriented in the direction 14. When the carriage 4 is moved in the direction of displacement 14 in the direction of towing shown by the arrow A in Figure 2 (second side 41 to first side 40 of the carriage 4 or second side 52 to the first side 51 of the rolling unit 25), the wheel 80 rotates in the direction shown by the arrow A 'in Figure 2. The hub 75 then tends, for the reasons explained above, to be behind the bearing 79 with the wheel 80 which is oriented in the direction of movement 14.

When the wheel 80 is thus oriented, as illustrated in Figure 2, the cross member 82 is in line with the wheel 80, behind the hub 75. The two teeth 81 of the fork 45 are then arranged on the right side. other of the wheel 80, that is to say that each tooth 81 is facing a lateral surface of the wheel 80.

The wheel 80 can therefore not pivot about the bearing 79 beyond an angular position where one of the lateral surfaces of the wheel 80 is in contact with one of the teeth 81. The gap between the teeth 81 being slightly larger than the width of the wheel 80 so that it can rotate around the hub 75, the wheel 80 can pivot slightly around the bearing 79, but these slight pivoting are irrelevant because they do not allow the carriage 4 or the rolling unit 25 to move laterally.

The fork 45 thus prevents the wheel 80 from taking another orientation, that is to say that the fork 45 keeps the wheel 81 oriented in the direction of movement 14.

Note that when the wheel 80 is in contact with a tooth 81, since the wheel 80 rotates in the direction A ', the fork 45 is caused to tilt in the opposite direction, where the teeth 81 are close to the body 60, which forms an abutment stopping the tilting movement. The teeth 81 therefore remain on either side of the wheel 80.

Thus, when the carriage 4 is moved in the direction of travel 14 in the direction of towing shown by the arrow A in Figure 2, the wheels 80 are fixed orientation, in this case maintained oriented in the direction of movement 14. It will be observed, as can be seen in FIG. 2, that the teeth 81 extend over the entire thickness of the rolling lining 37 of the wheel 80, which is favorable for the cooperation between the wheel 80 and the teeth 81. When the carriage 4 is moved in the direction of displacement 14 in the pushing direction shown by the arrow B in FIG. 3 (first side 40 to second side 41 of the carriage 4 or first side 51 to second side 52 of the rolling unit 25), the wheel 80 rotates in the direction shown by the arrow B 'in FIG. 3. The hub 75 then tends, for the reasons explained above, to be behind the bearing 79 with the wheel 80 which is oriented in the direction of d 14 investment, as shown in Figure 3.

The member 60 is then in a position oriented at 180 ° to the position illustrated in FIG. 2, with the wheel 80 which is away from the fork 45 since the fork 45 is then in front of the bearing 79 which is - Even in front of the hub 75. The fork 45 does not act on the wheel 80, which can therefore move freely.

Thus, when the carriage 4 is moved in the direction of movement 14 in the direction of pushing shown by the arrow B in Figure 3, the wheels 80 are freely adjustable. Thus, the rolling unit 25 has an orientation locking configuration of the wheel 80 in the direction 14, illustrated in FIG. 2, and a free orientation configuration of the wheel 80, illustrated in FIG. note that in the orientation lock configuration illustrated in Figure 2 as well as in the free orientation configuration shown in Figure 3, the teeth 81 are in a rest position they take in the absence of stress, here simply because of their weight given the pendulum mounting of the fork 45. The fork 45 can tilt, turning in the direction which is seen as the counterclockwise direction in Figures 2 to 4 (direction of the arrow A '), from the rest position (Figures 2 and 3) to a release position shown in Figure 4. If the fork 45 is in the release position shown in Figure 4 and the wheel 80 is oriented as shown in Figure 2, i.e. in the direction of displacement 14 with the hub 75 located on the second side 52, each tooth 81 is in a release position where it is not facing the wheel 80, which is not between the teeth 81. The The wheel 80 can then pivot about the bearing 79. The transition from one to the other of the orientation locking configuration (FIG. 2) and of the free orientation configuration (FIG. 3) occurs as follows. considering for example that initially the wheel 80 is in orientation locking configuration (Figure 2). If the carriage 4, and therefore the unit 25, is then moved in the pushing direction (in the direction opposite to the arrow A), the member 60 tends to pivot about the bearing 79 so that the hub 75 is rearward of the bearing 79, the wheel 80 then rubs on one of the teeth 81 while it rotates in the direction B '(direction opposite to that of the arrow A'), which causes the fork 45 to turn in the opposite direction (direction of the arrow A '), where it rises to the second side 52 of the unit 25, that is to say that the fork 45 tilts in the direction where it moves away from the member 60. When the teeth 81 reach the release position shown in Figure 4, the wheel 80 is released from between the teeth 81 and takes the free orientation configuration shown in Figure 3. If the carriage 4, and therefore the unit 25, is then moved in opposite direction, the member 60 pivots, the wheel 80 approaches the fork 45 and comes knocking one of the teeth 81 on the outer side, which in turn the fork 45 is raised to the second side 52 of the unit 25, that is, the fork 45 tilts in the direction away from the member 60, the teeth 81 reach the position release, the wheel 80 is oriented in the direction of movement 14, the fork 45 tilts in the opposite direction under the effect of its weight, and the wheel 80 is found between the teeth 81 while being in the blocking configuration d orientation illustrated in Figure 2.

Thus, the passage between one and the other of the orientation locking configuration and the free orientation configuration is done automatically through the interaction between the wheel 80 and the fork 45. The carriage 4 comprises two rolling units 25, located on the second side 41, to provide the wheels 80.

Each unit 25 is fixed on the frame 42 by the support 50, here with bolts 31. The carriage 4 also comprises two rolling units 26, located on the first side 40, to provide the wheels 70. The rolling units 26 are similar to the rolling units 25, except that they do not include a fork 45. It will be observed that the tab 53 of the support 50 of each rolling unit 25 forms a bearing surface of the second side 41 of the carriage 4. Such a bearing surface is useful when the second side 41 of the carriage 4 is against another element, for example another carriage.

It will be noted that the rolling units 26 are commercially available and that here each rolling unit 25 has been prepared from a rolling unit such as 26 to which the fork 45 has been added thanks to the support 50. observe that the rolling unit 25 can thus be obtained in a particularly simple and economical way.

An example of use of the carriage 4 will now be described. FIG. 5 schematically represents a warehouse comprising racks 1 which define between them aisles 10 in which two operators 2 and 2 'circulate to collect articles arranged on the racks. 1.

A first operator 2, shown below in Figure 5, takes with him the carriage 4 by pulling it. A second operator 2 ', shown in the center of Figure 5, takes with him the carriage 4 by pushing it. Thus, the first operator 2 is located in front of the carriage 4 with respect to the direction of movement represented by the arrow 20 (direction of towing, corresponding to the arrow A of FIG. 2), whereas the second operator 2 'is located in rear of the carriage 4 relative to the direction of movement represented by the arrow 20 '(direction of pushing, corresponding to the direction of arrow B of Figure 4).

In the towing direction (operator 2), maintaining the orientation of the wheels 80 (which are behind) allows the carriage 4 to remain in its path, without lateral drift. In the pushing direction (operator 2 '), the freedom of orientation of all the wheels, that is to say both the wheels 70 (which are behind) and the wheels 80 (which are in front), allows the carriage 4 to be moved with high maneuverability qualities. Indeed, a carriage with all the wheels are free of orientation is easy to maneuver because it is easily driven to the desired position, both in the direction of displacement 14 (longitudinal direction or front-back) and in the direction transverse to the direction 14 (lateral or left-right direction).

The absence of resistance to lateral movements makes it possible, for example, to easily position the carriage 4 on a slot parking space. It is also easy to move the carriage 4 in the aisles 10, as the operator 2 ', including when the aisles 10 are narrow, to retrieve items to collect and arrange them on the carriage 4, for example to fill crates carried by this cart. Such crates being then in front of the operator, he can fill them particularly easily.

When the collection of articles is complete, the direction of movement is reversed to go to the direction of towing where the carriage 4 is pulled as does the operator 2, the wheels 80 go into orientation lock configuration, and it is then easy to move the carriage 4 outside the aisles 10 to travel great distances.

Indeed, the two wheels 80, which are then in orientation locking configuration (Figure 2), avoid the lateral drifts of the carriage, that is to say that the carriage 4 is crooked. Without the wheel orientation lock 80, the control of the trajectory of the carriage 4 by the operator 2 would be tiring and would work the lumbar excessively.

Unlike a similar carriage but whose wheels 80 are fixed orientation, the carriage 4 has a different ground relation S depending on whether it is moved in the direction of towing (second side 41 to first side 40) or in the direction of the pushing (first side 40 to second side 41): - in the direction of towing, the carriage 4 has a nominal ground relation in which the wheels 70 are freely steerable and the wheels 80 maintained oriented in the direction of movement 14, and - in the direction of pushing, the carriage 4 has this nominal ground relation except that the wheels 80 are freely steerable.

The set of carriages 3 illustrated in FIGS. 6 and 7 is formed by the carriage 4 and a carriage 5 connected by a hitch 6. The carriage 5 is identical to the carriage 4.

For simplicity, the same reference numerals are used for the carriage 5 as for the carriage 4. In FIGS. 6 and 7, the direction of movement 14 of the carriage 4 and the direction of movement of the carriage 15 are aligned, but it is understood that the hitch 6 allows the carriages 4 and 5 to have differently oriented directions of movement, for example when the assembly 3 is towed and makes a turn as seen at the bottom of Figure 8. The hitch 6 is formed with the hook 61 of the carriage 4 and the drawbar 62 of the carriage 5.

As indicated above, the slot 65 of the drawbar 62 of the carriage 5 is configured to receive the hook 61 of the carriage 4 and to allow it to slide there. Thus, the hitch 6: - admits the extended position shown in Figure 6, where the second side 41 of the carriage 4 and the first side 40 of the carriage 5 are spaced apart from each other; - Admits the retracted position shown in Figure 7 where the second side 41 of the carriage 4 and the first side 40 of the carriage 5 are brought closer to each other; and - allows the passage from one to the other of the deployed position and the retracted position by simply sliding the hook 61 along the slot 65 of the drawbar 62. The retracted position (Figure 7) of the coupling 6 allows to store or transport the assembly 3, for example in a truck or in a freight elevator, without loss of space since the carriages 4 and 5 are then against each other. The hitch 6 is in the extended position (Figure 6) when the assembly 3 is towed, for example as shown below in Figure 8, namely when the assembly 3 is moved by pulling the carriage 4 of the first side 40 The carriage 4 and the carriage 5 are then moved in the towing direction (second side 41 towards the first side 40).

The hitch 6 is in the retracted position (Figure 7) when the assembly 3 is pushed, for example as shown in the center of Figure 8, namely that the assembly 3 is moved by pushing on the carriage 4 of the first side 40 The carriage 4 and the carriage 5 are then moved in the pushing direction (first side 40 to second side 41). The drawbar 62 is connected to the frame 42 by a pivot link 62a. It further has a lower end, located under the frame 42, which is bent. An elastic return element 63, here a spring acting in tension, is hooked on the one hand to an anchor point 64 (Figure 1) fixed under the frame 42 and on the other hand to the curved lower end of the tongue 62 The elastic return element 63 thus makes it possible to bias the drawbar 62 towards a rectified position. The hook 61 is mainly formed of a curved bar preferably pointing towards the ground S on which it is expected that rolls the assembly 3. Thus, the hook 61 cooperates naturally with the slot 65 of the drawbar 62. Here, the hook 61 further comprises a washer 61a forming for example a stop for the drawbar 62. We will now describe an example of use of the assembly 3. Figure 8 is similar to Figure 5 but the operators 2 and 2 'take the lead together 3 rather than the single carriage 4. In the towing direction (operator 2), the gap between the carriages 4 and 5 allows them to change orientation without interfering with each other; the freedom of orientation of the wheels 70 (which are forward) allows each carriage to easily change orientation; and maintaining the orientation of the wheels 80 (which are behind) allows each carriage to remain in its path, without lateral drift. Note that without the modification of the ground relation S of the carriage 4 and the carriage 5, the assembly 3 would be difficult to maneuver in the pushing direction (operator 2 '), since the wheels 80 (which would then be the front wheels) prevent lateral movements of the carriage 4 and the carriage 5, and therefore more generally of the assembly 3 since the first carriage 4 and the second carriage 5 are then against each other.

In the variant illustrated in Figure 9, the assembly 3 comprises, in addition to the carriage 4 and the carriage 5, a third carriage 16. The carriage 16 is identical to the carriages 4 and 5. The carriage 5 and the carriage 16 are connected. by a hitch 17 in the same way as the carriage 4 and the carriage 5 are connected by the hitch 6. In a general manner, in the variant of the assembly 3 illustrated in FIG. 9, the second carriage 5 and the third trolley 16 cooperate in the same way as the first trolley 4 and the second trolley 5. In variants not shown, one or more additional trolleys are added, with each pair of two neighboring trolleys cooperating as the trolley 4 and the trolley 5. In a variant not illustrated, where the carriage 4 is used alone, the carriage 4 rather than having two rolling units 26 of the first side 40 and two rolling units 25 of the second side 41 have four rolling units. 25, rolling units 25 of the first side 40 being in mirror image of the rolling units 25 arranged on the side 41: thus, whatever the direction of movement of the carriage 4, it will always have the front wheels free of orientation and the rear wheels with fixed orientation . It will be observed that in each of the carriages described above, there are no wheels other than the wheels of the first couple and the second pair. In variants not shown, there are more wheels, for example the described single wheels are replaced by twin wheels and / or a free wheel with free orientation is provided. In other variants not shown, there are fewer wheels, for example a single wheel with the movable member which is a wheelbarrow. In non-illustrated variants: the fork 45 is shaped differently, for example with a shape in H rather than in U; - The teeth 81 are individual rather than being rigidly associated with each other, for example each being pivotally mounted on the support 50; - The teeth 81 are biased to their rest position other than by pendulum mounting under the effect of their weight, for example by involving a spring; the passage between the one and the other of the blocking configuration (FIG. 2) and of the free configuration (FIG. 3) is effected otherwise than by direct interaction between the wheel 80 and the teeth 81, for example with a electric actuator which puts the teeth 81 in the release position (Figure 3) when the hitch connecting the carriage concerned to another carriage is in the retracted position; - The wheel 80 of the rolling unit 25 is shaped differently, for example with side disks to cooperate with the teeth 81 to prevent the side wear of the rolling lining 37; the member 60 for holding the hub 75 is shaped differently, with for example a single leg such as the leg 77; - The support 50 is shaped differently, with for example a curved contour rather than rectangular; - Fixing between the support 50 and the frame 42 is performed other than by bolts, for example by rivets; - The metal elements of the rolling unit 25 or 26 and / or the carriage 4 are replaced by elements made of a material other than metal, for example a plastic material; the support 50 is not separated from the frame 42 but forms part of it directly; and / or the rolling unit is part of a moving element other than a handling truck, for example a supermarket trolley or a child's stroller. Many other variants are possible depending on the circumstances, and it is recalled in this regard that the invention is not limited to the examples described and shown. 30

Claims (10)

CLAIMS1 Rolling unit comprising: - a support (50) configured to be arranged in a predetermined direction of movement (14); - a wheel (80) having a hub (75), configured to roll on a floor (S) with the hub (75) which is oriented parallel to said floor (S); - a member (60) for holding said wheel (80) by its hub (75); - A bearing (79) for pivotally mounting the holding member (60) on the support (50), configured to be oriented transversely to said ground (S), the bearing (79) and the hub (75) being in position. offset from each other; and a wheel orientation blocking device (80), configured so that the wheel (80), as it rotates in a first direction (A ') or a second direction (B'), is respectively fixed orientation in said direction of movement (14) or free orientation; characterized in that said wheel orientation locking device comprises two teeth (81) mounted on the support (50) to tilt along said direction of travel (14), said teeth (81) taking in the absence biasing a predetermined rest position; said wheel (80), said holding member (60) and said teeth (81) being configured so that the rolling unit (25) has: - an orientation locking configuration of the wheel (80) in said direction moving (14), wherein the teeth (81) are in the rest position and the wheel (80) is between the teeth (81); and - a free orientation configuration of the wheel (80), wherein the wheel (80) is not located between the teeth (81); each tooth (81) being configured to tilt, from the rest position while the rolling unit is in the orientation lock configuration, away from the holding member (60) to a position release position where the wheel (80) is no longer between the teeth (81) and can move freely. 2. Rolling unit according to claim 1, characterized in that said wheel (80) and said teeth (81) are configured so that the passage between one and the other of the orientation locking configuration and the Free orientation configuration is achieved automatically by direct interaction between the wheel (80) and the teeth (81). 3. Rolling unit according to claim 2, characterized in that the teeth (81) swing from the rest position to the release position by rotating in the same direction as the first direction of rotation (A '). of the wheel (80), and said direct interaction between the wheel (80) and the teeth (81) is such that when the wheel (80) is between the teeth (81) and rotates, in contact with a tooth (81) ) the wheel urges the tooth (81) to tilt by turning in the opposite direction of the wheel (80). 4. Rolling unit according to any one of claims 1 to 3, characterized in that the teeth (81) are rigidly associated with each other. 5. Rolling unit according to claim 4, characterized in that the teeth (81) are part of a fork (45) having a cross member (82) which project the teeth (81), said cross member (82) being mounted tilting on said support (50) and oriented transversely to the direction of movement (14). 6. Rolling unit according to any one of claims 1 to 5, characterized in that the teeth (81) extend over the entire thickness of a rolling lining (37) that comprises the wheel (80). 7. Mobile element comprising at least one wheel, characterized in that said wheel (80) is part of a rolling unit (25) according to any one of claims 1 to 6. Mobile element according to Claim 7, characterized in that it extends in a predetermined direction of movement (14) between a first side (40) and a second side (41), with a first side (40) first pair (7) of freely steerable wheels (70) and second side (41) a second pair (8) of wheels (80) each of which is part of a rolling unit (25) according to any one of the claims 1 to 6, which rolling units (25) have their direction of movement corresponding to the direction of movement (14) of the movable member (4) and have their wheel (80) which rotates in the first direction (A ') when the movable member (4) is moved in a first direction (A) from the second side (41) to the first side (40) and their wheel (80) which rotates in the second direction (B ') when the movable element (4) is moved in a second direction (B) from the first side (40) to the second side (41), whereby the element mobile (4) has a different ground relation (S) depending on whether it is moved in the first direction (A) or in the second direction (B): in the first direction (A), the movable element (4) has a nominal ground relation in which the wheels (70) of the first pair (7) are freely steerable and the wheels (80) of the second pair (8) are kept oriented in the direction of movement (14), and in the second direction (B), the movable element (4) has this nominal ground relation except that the wheels (80) of the second pair (8) are freely steerable. 9. An assembly comprising a plurality of movable elements (4, 5, 16) according to claim 8, with each movable element (4, 5, 16) which is connected to a neighboring mobile element by a hitch (6, 17). 10. An assembly according to claim 9, characterized in that each said hitch (6, 17) comprises a hook (61) and a drawbar (62) movable to slide relative to each other so that the hitch ( 6, 17) has an extended position in which the mutually facing sides (41, 40) of the connected movable members (4, 5, 16) are spaced from each other and that the hitch (6, 17) has a retracted position in which the sides (41, 40) facing each other are reconciled.