Abstract:
The present disclosure relates to a juvenile stroller. The stroller includes a seat, wheels, and a push handle. The push handle is mounted for pivoting movement about an axis relative to the seat.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of the invention is that of child care. More precisely, the invention relates to carriages for children, or strollers. Certain strollers, referred to in what follows as convertible, are designed to be able to be used in several configurations, and more particularly to be attached to a bicycle. 
         [0002]    This invention relates particularly to such strollers which can be transformed into a trailer for a bicycle. 
       Solutions of Prior Art 
       [0003]    Several models of strollers have already been designed in different configurations, namely a “stroller” position and a “trailer” position. 
         [0004]    Strollers are as such known that can be connected to a bicycle. Such strollers are for example described in document DE 299 19 159 and include, in this case, a handlebar that can be tilted forwards in order to take a horizontal position when it is intended to be connected to a bicycle. According to this document, the passage in “trailer” position is complex, and requires in particular the removal of the front wheels and the handle, in order to replace it with a tow bar. Furthermore, the transport case that plays the role of a seat for the child must also be removed then remounted. 
         [0005]    Document DE 10 2005 029 448 discloses an alternative of this type of stroller wherein the tilting of the handlebar controls, via a set of connecting rods, the height of the seat in such a way that the latter is lowered, in the “trailer” position. This is a complex, cumbersome and expensive mechanism. According to this document, the handlebar can be transformed into a tow bar in the “trailer” position subject to having first opened the latter in order to pivot a portion of it according to the axis of the hitch and attach this portion to the hub of the rear wheel of the bicycle. 
         [0006]    Furthermore, according to the technique of this document, the front wheels of the stroller remain in contact with the ground in “trailer” position. In this position, the ensemble is therefore difficult to handle, in particular in curves, and is cumbersome. 
         [0007]    As such, strollers that can be converted into a trailer of prior art have several disadvantages, which have the consequence of having problems concerning practicality, ergonomics, safety and manufacturing complexity. 
         [0008]    One of the disadvantages of these strollers that can be converted into a trailer is therefore the complexity of their mechanism for changing configuration. Indeed, this mechanism requires operations for adapting the chassis (removal and/or opening of the handlebar) in order to be connected to the bicycle. It is therefore not very easy to use them, and manufacturing them is complex. It is consequently expensive to manufacture these strollers. 
         [0009]    Furthermore, due to the multiplicity of the movements and operations required, users do not use, or use very little, the possibility of changing positions. These operations must moreover be carried out empty, without a child being installed in the seat. The change in position therefore supposes taking the child out of the seat, leaving him to wait next to the stroller, performing the manipulations (which does not make it possible to carry or hold the child), then to install the child again in the seat. 
         [0010]    In addition, this complexity leads to heavy products, and which therefore are not adapted in particular for towing using a bicycle. These strollers are consequently, generally, not very ergonomic and are difficult to use, in the “stroller” position as well as in the “trailer” position. 
         [0011]    Yet another disadvantage of some of these strollers that can be converted into a trailer of prior is the need to remove, then store, the front wheel or wheels of the stroller during the change of position. 
       OBJECTIVES OF THE INVENTION 
       [0012]    The invention has in particular for objective to overcome these disadvantages of prior art. 
         [0013]    More precisely, an objective of the invention is to provide a stroller that can switch simply and easily from a stroller position to a trailer position. 
         [0014]    Another objective of the invention is, according to at least one embodiment, to provide such a stroller of which the use in its trailer position is particularly easy and comfortable for the user. 
         [0015]    Another objective of the invention is, according to at least one embodiment, to provide a stroller that can be transformed into a trailer without requiring removing the child during this change of position and without resulting in discomfort or a risk for the child. 
         [0016]    Yet another objective of the invention is, according to at least one embodiment, to provide such a stroller that offers a good level of comfort for the child transported, whether in the stroller position or in the trailer position. 
         [0017]    An objective of the invention is, according to at least one embodiment, to provide such a stroller that is easy to manufacture, and of reduced cost. 
       EXPOSURE OF THE INVENTION 
       [0018]    These objectives, as well as others that shall appear in what follows, are achieved using a stroller for a child, which is convertible into a bicycle trailer, comprising a chassis carrying at least one seat and a handlebar. 
         [0019]    According to the invention said handlebar is hingedly mounted in relation to said chassis and able to tilt between:
       a “stroller” position, wherein an end portion, referred to as the gripping area, of said handlebar makes it possible to guide and move said stroller, and   a “trailer” position, wherein said gripping area of the handlebar can be secured to a bicycle.       
 
         [0022]    In addition, the stroller comprises means for stowing a front wheel or wheels, controlled by the tilting of said handlebar, with the front wheel or wheels being in an operational position, in contact with the ground, in “stroller” position, and in a stowed position, not interacting with the ground in “trailer” position. 
         [0023]    As such, according to the invention, the end portion of the handlebar, here called the gripping area, is used in the two positions. In the “stroller” position, it conventionally forms the handle or handles, i.e. the area where the user places his hands in order to push and guide the stroller. In the “trailer” position, this same gripping area constitutes the securing element to the bicycle. 
         [0024]    Moreover, the tilting of the handlebar drives the stowing or the automatic setting into place of the said front wheel or wheels. Consequently, the change from the “stroller” to “trailer” position, or inversely, requires only a simple tilting of the handlebar, of which the end plays both the role of guiding the stroller in “stroller” position then as an attaching in “trailer” position. 
         [0025]    “Trailer” position means a position of the stroller able to be connected to the bicycle. Once this “trailer” position is established, the user only has to fasten the bicycle and this without modifying the position of the seat, and while retaining the direction of displacement of the whole (regardless of the position, the child faces forward). 
         [0026]    In other terms, the conversion implemented according to the invention makes it possible to retain the orientation of the child with respect to the displacement. Indeed, according to this invention, the child will always be placed in the forward direction. As such, the conversion of the stroller into a trailer (or inversely) does not introduce any change in the orientation of the child which provides him with comfort. 
         [0027]    The invention makes it possible to avoid, since everything is carried out by a simple tilting of the handlebar, any operation of removal or of adapting the chassis in order to switch to “trailer” position. In particular, it is not necessary to remove the front wheels and/or the handlebar in order to switch to “trailer” position. 
         [0028]    It is as such possible to perform this change in position even in the presence of the child. As such the child remains attached to the stroller, for example by means of a harness, such as a five-point anchoring harness, during the change in position which guarantees his safety. 
         [0029]    Moreover, due to the fact that the change in position can, according to the invention, be carried out in the presence of the child, time is saved in performing such a conversion. It is as such possible, for example, to use the stroller in the “trailer” position to transport the child to the park, by bicycle, to park the bicycle and to continue the walk in the park (or indoors, for example in a shop), in “stroller” position. 
         [0030]    As such, the stroller that can be transformed into a trailer for a bicycle according to the invention is extremely practical, due to the fact that the change in position is easy and rapid. 
         [0031]    Note that the stroller according to the invention can include one or several seats that may or may not be removable, where applicable independent from one another, allowing for the transport of one or two or more children, in order to form a double stroller (two children), and even a triple stroller (three children). 
         [0032]    In this case, the stroller can be a double stroller/trailer that makes it possible to install and transport two children side by side (in this case the chassis carries two neighbouring seats arranged in the same plane or a double seat) or one behind the other (in this case the chassis carries two seats arranged one behind the other). 
         [0033]    The seat is chosen from among a plurality of different seats, suited to the different ages of the child or which allows for different positions: a seat, sometimes called a “hammock”, which can be foldable or rigid, a rigid shell that can also be used as a car seat, a nacelle making it possible to transport a baby in a lying down position, etc. 
         [0034]    The seat or seats can be removable and/or independent, for example in order to make it possible to incline the backrest of one seat without inclining the other seat. 
         [0035]    According to an advantageous embodiment of the invention, in said stowed position, the front wheel or wheels are displaced under said at least one seat carried by the chassis. 
         [0036]    The displacement of the wheels under the seat (with this term encompassing, in what follows, the case where there are several seats) limits the space taken up by the hitch and makes it possible to prevent the child or the cyclist from getting injured during the handling of the trailer. 
         [0037]    For example, according to a simple alternative of this embodiment, it can be considered that the front wheel or wheels are folded back flat under the seat. 
         [0038]    According to another alternative of this embodiment, a housing specifically provided for accommodating the front wheel or wheels is provided under the seat in such a way that the front wheel or wheels are completely or partially integrated through nesting under the seat. 
         [0039]    Advantageously, the front wheel or wheels are carried by two front shafts extending in the extension of two uprights of said handlebar, with the front shafts tilting simultaneously with said uprights. 
         [0040]    As such, the front wheel or wheels are connected to the handlebar in such a way that the pivoting of the handlebar necessarily results in the stowing of the wheel or wheels. 
         [0041]    This can in particular be a wheel or a single block of wheels. 
         [0042]    Preferentially, on each side of the stroller, a front shaft and an upright form the same part. 
         [0043]    As such, the cost of manufacturing the stroller is reduced due to the fact that the number of parts comprising it is limited. 
         [0044]    Advantageously, the chassis, or said one seat carried by said chassis, carries two hinging nodes, allowing for the tilting. 
         [0045]    The implementing of the tilting is therefore simple due to the fact that the hinging nodes provide fluidity of the tilting in such a way as to limit the shaking that could occur during the change in position. 
         [0046]    Preferentially, at least one of the nodes carries means for blocking, able to maintain the handlebar in the “stroller” position and/or in said “trailer” position, and means of unlocking, making it possible to release said means for blocking in order to tilt said handlebar. 
         [0047]    These means for blocking therefore make it possible to secure each position of the stroller that is convertible into a bicycle trailer according to the invention. 
         [0048]    According to an alternative embodiment, the stroller comprises, in the vicinity of the front wheel or wheels, a first element for locking, able to cooperate respectively with:
       in the “stroller” position, a second complementary element for locking mounted in the vicinity of a footboard secured to said seat; and   in the “trailer” position, a third additional element for locking mounted in the vicinity of the lower portion of the backrest of said seat.       
 
         [0051]    This approach makes it possible to obtain a robust locking in the two positions, and makes it possible to limit the possible play felt on the handlebar. 
         [0052]    Means for unlocking can be provided, in order to release said means for blocking or said elements for locking in order to allow for the tilting of said handlebar, comprising an unlocking control mounted on the backrest of said seat and at least one transmission cable. 
         [0053]    Advantageously, the length of said front shafts represents between 25 and 35% of the length of said uprights. 
         [0054]    Such a proportion between the uprights and the shafts makes it possible in particular to retain balance and stability in the two positions, and during the change in position. In particular, the front wheel or wheels can roll on the ground during a portion of the tilting, which makes the change in position easier and more comfortable, the seat remaining substantially in a normal inclination. 
         [0055]    According to a particular embodiment, said seat carries said handlebar and/or bases of the rear wheel. 
         [0056]    A self-carried structure is as such formed, that is particularly simple to implement. 
     
    
     
       LIST OF FIGURES 
         [0057]    Other characteristics and advantages of the invention shall appear more clearly when reading the following description of a preferred embodiment, provided as a simple example for the purposes of information and which is not restricted, and the annexed drawings, among which: 
           [0058]      FIGS. 1A and 1B  respectively show in perspective an embodiment of the invention in stroller position and in trailer position; 
           [0059]      FIGS. 2A and 2B  respectively show as a side view an embodiment of the invention in stroller position and in trailer position; 
           [0060]      FIGS. 3A and 3B  respectively show as a front view an embodiment of the invention in stroller position and in trailer position; 
           [0061]      FIGS. 4A and 4B  respectively show as a rear view an embodiment of the invention in stroller position and in trailer position; 
           [0062]      FIGS. 5A and 5B  respectively show as a top view an embodiment of the invention in stroller position and in trailer position; 
           [0063]      FIG. 6  shows the stroller according to the invention in trailer position attached to a bicycle; 
           [0064]      FIGS. 7A to 7D  show various steps relating to the fastening of the stroller in trailer position to a bicycle; 
           [0065]      FIG. 8  shows an alternative of the means for fastening to a bicycle; 
           [0066]      FIG. 9  shows the stroller in folded position according to an embodiment of the invention; 
           [0067]      FIGS. 10A and 10B  diagrammatically show an alternative of the blocking of the stroller of the invention in the two positions. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     1. Reminder of the Principle of the Invention 
       [0068]    The general principle of the invention is based on the tilting of the handlebar of the stroller, which allows on the one hand the switching of the stroller from the “stroller” position to the “trailer” position or inversely, and on the other hand the stowing of the front wheels of the stroller, in the “trailer” position, or their deployment in the “stroller” position. 
         [0069]    As such, when the stroller comprises a single seat (embodiment described in what follows), in “stroller” position the upper end of the handlebar is placed at the rear of the seat transporting the child and the front wheel or wheels are deployed (in contact with the ground), while in “trailer” position the handlebar is tilted with respect to the seat, or to the chassis, so that its upper end can be attached to the rear of a bicycle. The tilting of the handlebar automatically actuates the means for stowing the front wheel or wheels. 
         [0070]    The passing from the “stroller” position to the “trailer” position is therefore simple and rapid and makes it possible to limit the load of the trailer felt by the cyclist while also relieving him of the operations of disassembly the stroller. The cyclist can therefore avoid having to carry tools for disassembly when he leaves for a walk, and does not have to worry about storing disassembled elements. 
       2. The Stroller in “Stroller” Position 
       [0071]      FIG. 1A  shows a perspective view of the stroller in “stroller” position according to an embodiment of the invention, in a conventional configuration with three wheels (or blocks of wheels). It is clear that, in the scope of the invention, the stroller can also have four wheels. 
         [0072]    In this embodiment shown in  FIG. 1A , the stroller comprises a single seat. Note that the stroller can also comprise several removable and independent seats allowing for the transport of several children (for example two or three) side by side or one behind the other. 
         [0073]    The base of this stroller is formed of a chassis  1 , which for example implements tubular elements. In the embodiment shown, the seat  4  functionally provides a part of the functions of the chassis, in particular by directly carrying the rear bases  14  and the hinging nodes  12 . A “self-carrying” chassis is as such formed, that is very simple and well adapted to the two positions of transport of the invention. Of course, it is possible, without leaving the scope of the invention, to provide a more conventional chassis, that interconnects all of the wheels and carrying at least one seat (that can then be removed and can be interchanged). 
         [0074]    In this embodiment, the chassis, and more precisely the seat  4 , carries on each side a hinging node  12  allowing the tilting of a handlebar  11  between the “stroller” position shown in  FIG. 1A , and the trailer position shown in  FIG. 1B . 
         [0075]    The chassis further comprises two rear bases  14  each carrying a rear wheel  21 , referred to as main wheels, which extends substantially perpendicularly to the forward direction of the stroller and therefore consequently the direction of the handlebar  11 . 
         [0076]    The rear bases  14  can for example be formed in a single part, substantially forming an open U, of which the base is secured to the seat by any suitable means. 
         [0077]    The main wheels  21  are advantageously wheels of large diameter for example 16 inches in order to facilitate moving over obstacles, such as pavements, steps, holes, bumps, passages through the sand or on gravel. Such wheels are furthermore adapted to a use towed by a bicycle. 
         [0078]    In the embodiment shown, the rear bases  14  are inclined towards the rear, in such a way as to offset towards the rear the axis of the rear wheels  21 , which are as such located, in the “stroller” position, substantially in the same vertical plane as the upper end of the handlebar. 
         [0079]    According to an alternative embodiment not shown, the chassis can also comprise means of damping, which can be constituted, for example, by an element made of rubber or by a spring. They as such provide the suspension for the stroller in the “stroller” position as well as in its “trailer” position. 
         [0080]    These means of damping can for example be placed on the wheels and/or on the connection between the rear bases and the seat. 
         [0081]    The handlebar  11  is formed of two uprights  110  arranged on either side of the stroller and connected to the hinging nodes  12  in such a way as to surround the seat  4  that carries the child. The two uprights  110  are extended by a cross-member that corresponds to a gripping area  16 . 
         [0082]    Diagrammatically, in this embodiment, the handlebar therefore has a general U-shape, and the gripping area  16  corresponds to the base of this U. 
         [0083]    The cross-member  16  comprises, in this embodiment, two sections  161  and  162  forming handles, connected by a third central section  163  with a diameter less than that of the sections  161  and  162 . This third section  163  is used for the fastening in “trailer” position to the bicycle. 
         [0084]    According to an embodiment, the central section  163  is suited to facilitate the connection to a bicycle, and has for example a hole or a blind hole pierced transversally and perpendicularly to the direction of displacement of the stroller in “trailer” position. In other terms, the section  163  is here pierced according to the vertical with respect to the horizontal position of the handlebar  11 . 
         [0085]    Other forms of handlebars, and consequently of connections with a bicycle, can be considered. In particular, it is possible that the handlebar connected be replaced with two unconnected pushers, each provided with a handle forming a gripping area, in the “stroller” position. In this case, according to the embodiments, one or both pushers are secured to the bicycle, on the handles, in the “trailer” position. 
         [0086]    It is therefore the gripping area  16 , i.e. the upper end of the handlebar  11  in the “stroller” position, which provides a double function, on the one hand a handle (more generally an area where the user places his hand or hands to push and direct the stroller), in the “stroller” position and on the other hand of an area secured with the bicycle, in the “trailer” position. 
         [0087]    The uprights  110  can also be adjustable in length and/or in height, for example by means of a telescopic adjustment. 
         [0088]    At the front end of the stroller, a front base, also called a shaft  3  is fastened to each hinging node  12 . A front wheel  31 , or secondary wheel, is mounted at the lower end of these front bases  3  which, in the embodiment shown, are connected and are formed in the same part  5 . 
         [0089]    According to the alternatives, the axis of the front wheel is fixed or is mounted mobile pivoting with respect to a vertical axis. It can also be selectively fixed or mobile. In this latter case, two fixed positions can be provided, one for the “stroller” position and the other for the “trailer” position, taken automatically during the tilting. Moreover, the front wheel ( 31 ) can be replaced with a block of wheels, comprising two neighbouring wheels. 
         [0090]    In the embodiment shown, the uprights  110  of the handlebar are extended by the front bases  3 , which are formed in the same part. In other embodiments, this can of course be separate elements, linked on the hinging nodes  12 . 
         [0091]    The seat corresponds, in this embodiment, to an enveloping seat  4 , provided with lateral elements that allow for good protection of the child. This here is a large-size seat, adapted for the transport of a child up to the age of 4 year for example, and even older. Reducers, elements of comfort, and other seats allowing for the transport of several children, can of course be provided. 
         [0092]    According to the alternative shown, the hammock forms an element of the chassis, and carries the rear bases and the hinging nodes. According to another alternative, the hammock can be removed and be for example replaced with a shell or a nacelle. In this case, conventional means, such as those used by the Applicant and known under the registered trademark “Moduloclip” can be used to secure the hammock, or any other element, to the chassis. 
         [0093]    This hammock, shell or nacelle can be provided with a safety harness in order to maintain the child in the seat constituted as such. 
         [0094]    A seatbelt (not shown) can also be integrated when the child is older. 
         [0095]    According to an alternative, a removable protective cover for inclement weather can also be secured/removed from the stroller. 
         [0096]      FIGS. 2A, 3A, 4A and 5A  respectively show the side, front, rear and top views of the stroller in “stroller” position. In this position, the handlebar  11  is used to guide and move the stroller, in particular by pushing it or by pulling it. Moreover, in this “stroller” position, the front wheel or wheels are in direct contact with the ground. 
       3. The Stroller in “Trailer” Position 
       [0097]      FIG. 1B  shows a perspective view of the stroller in “trailer” position after tilting of the handlebar  11  with respect to the “stroller” position of  FIG. 1A . To switch from the conventional “stroller” position to the “trailer” position, only the tilting B 1  of the handlebar  11  is carried out, which automatically drives the stowing B 2  of the secondary wheel support  3 . 
         [0098]    Moreover, with regards to the embodiment shown in  FIG. 1B , the stroller in “trailer” position comprises a single seat. Note that the stroller can also comprise several seats that can be removed and which are independent allowing for the transport of at least several children (for example two or three) side by side and/or one behind the other. 
         [0099]    The front wheel  31  is for example moved under the seat  4  in such a way that the stroller in trailer position or hitched, now has only two wheels in contact with the ground, such as shown in particular more precisely by the side and rear views of  FIGS. 2B and 4B . 
         [0100]    As such, in the “trailer” position, only the rear wheels are active, which facilitates use by the cyclist, in comparison with a trailer position wherein the front wheels would be maintained in contact with the ground. 
         [0101]    The stowing B 2  of the front wheels under the seat is automatic and controlled by the tilting of the handlebar  11 . No operation of removing the handlebar or the front wheels is therefore required to hitch the stroller to the bicycle. 
         [0102]    Advantageously, the stowed position of the front wheel or wheels is secured by means of blocking (not shown) In particular, if the front wheel or wheels  31  can be mobile through pivoting, it can be provided that the switching to the “trailer” position result in an automatic return to the fixed position, in particular so that the wheel penetrates into a housing provided for this purpose under the seat. According to another approach, it can be provided that the front wheel  31  automatically take another fixed position, for example in order to extend flat under the seat. 
         [0103]    Means of blocking or braking can also be provided, preventing the wheel from rotating about itself. 
         [0104]    The child, present in the seat can remain in the seat during the passing from the “stroller position to the “trailer” position. Indeed, the dimensions of the front bases  3  and of the front wheel  31  are, according to this embodiment, chosen in such a way that the front wheel  31  remains in contact with the ground when a portion of the pivoting, without the inclination of the seat being substantially modified. 
         [0105]    For example, the length of the front bases  3  carrying the front wheel or wheels can represent 25 to 35% of the length of the uprights  110  of the handlebar  11 . 
         [0106]    Such a proportion between the uprights  110  and the bases (or shafts)  3  makes it possible in particular to maintain the balance and stability during the change in position from stroller to trailer and inversely. 
         [0107]    The conversion into a trailer (and inversely) according to the invention is therefore practical, rapid and secure for the child who does not need to be unattached, carried and lifted out of the seat, placed on the road and because of this exposed to the risks of the latter while the cyclist carries out the change in position of the stroller, then again carried and attached in the stroller once it is converted into a trailer. 
         [0108]    As such, the cyclist responsible for the child preserves his child from the risks of the route and preserves himself physically by avoiding the actions linked to displacing the child during the change in position of strollers that can be transformed into trailers of prior art. 
         [0109]    Furthermore, the balance and the comfort of the child are at least in part maintained during the change in position as the stability provided by the tilted position of the handlebar in order to be attached to the bicycle in trailer position substitutes for the stability procured by the front wheel or wheels in stroller position. It is possible, as a complement, to provide a stand, making it possible to maintain the stroller in the “trailer” position in the absence of a bicycle. 
         [0110]    According to an alternative not shown, it is also possible that the rear bases  14  be moved during the tilting, in such a way that the rear wheels  21  are placed substantially underneath the seat  4 . 
         [0111]    With regards to  FIGS. 1B, 2B and 4B , the front wheel  31  has therefore been stowed, by pivoting about an axis either upwards, or preferably under the seat  4 . 
         [0112]    According to an alternative embodiment, the handlebar can have an intermediate position, for storage, for example when it reaches a vertical position, skywards, and substantially parallel to the backrest of the seat of the child during the tipping frontwards of the seat in order to switch to “trailer” position, with the secondary wheel or wheels then being already stowed. 
         [0113]    It is also possible to provide, when the front bases and the uprights of the handlebar are separate elements, that the hinging nodes authorise a storage position wherein the handlebar is in the “stroller” position and the front wheel is stowed under the seat. 
         [0114]    As can be seen in  FIG. 4B , which shows the stroller seen from behind, in the “trailer” position, the front wheel or wheels are stowed under the seat portion  4  of the seat, between the two rear wheels. 
         [0115]    According to an alternative not shown, it is also possible to provide a housing within the seat or under the latter so that once retracted the secondary front wheel (or wheels) are at least partially hidden in this housing. The latter can be provided with a boss that rubs against the wheel, and which opposes the rotation thereof. 
         [0116]    According to another alternative not shown, it is also possible that the tilting of the handlebar causes a simultaneous modification in the height of the seat  4  with respect to the ground in order to adapt the height of the seat of the child so that he can see for example over the rear wheel of the bicycle to which he is attached. 
       4. The Pivoting Element: The Hinging Node 
       [0117]    The hinging node  12  allows for the tilting of the handlebar between the “stroller” position, in other terms when the handlebar is located behind the seat with respect to the direction of movement of the stroller, and the “trailer” position when the handlebar, after having passed over the seat and the head of the child, extends frontwards in the forward direction of the stroller towed by a bicycle. 
         [0118]    More precisely, the hinging node  12  comprises a fixed portion in relation to the chassis or, in the embodiment shown in relation to the seat, and a portion mobile in rotation in relation to this fixed portion, carrying the uprights of the handlebar. Two abutments are provided on the fixed portion, defining positions for stopping the tilting, corresponding respectively to the “stroller” position and to the “trailer” position. 
         [0119]    Where applicable, these abutments can be provided with damping elements. 
         [0120]    Moreover, means for locking each one of these positions can be provided, for example in the form of a clutch or of a pin that engages with a corresponding hole, on one of the nodes. A central button, for example, mounted on a spring, makes it possible to disengage the clutch or the pin, and to tilt the handlebar. In the absence of action on the button, the spring blocks the unit and prevents the tilting. 
         [0121]    This approach makes it possible, if needed, to define a storage position, as indicated hereinabove, and, if needed, several “stroller” positions (for example in order to propose several handlebar heights) and/or several “trailer” positions (for example in order to adapt to several heights or bicycle fasting methods). 
         [0122]    The unlocking can also be controlled remotely, as shown in the embodiment of  FIG. 9 . The control for unlocking  101  is placed on the top of the backrest of the seat  4 , and controls the unlocking of the node  12  by the intermediary of a transmission, such as a cable  102  (which can of course be concealed in the seat). This makes it possible to more easily control the movement of the handlebar, with one hand on the seat controlling the unlocking and one hand on the handlebar providing the movement of the latter. 
         [0123]    According to yet another approach, shown in  FIGS. 10A and 10B , the means for blocking can be located in different locations, according to the position of the handlebar. In the vicinity of the front wheel  31 , for example on the portion  33  that connects the two front bases  3  ( FIG. 3A ) and carrying the wheel support  34 , or on this wheel support  34 , or on one (even both) of the front bases  3 , a first element for locking  91  is provided. 
         [0124]    This first element for locking  91 , diagrammatically shown in  FIGS. 10A and 10B , can engage with two additional elements for locking  92 ,  93 , that are structurally identical and also shown diagrammatically in  FIGS. 10A and 10B , according to the position of the handlebar:
       in the “stroller” position ( FIG. 10A ), with a second complementary element for locking  92  which is mounted in the vicinity of the footboard  95  secured to the seat; and   in the “trailer” position ( FIG. 10B ), with a third additional element for locking  93  mounted in the vicinity of the lower portion of the backrest  94  of said seat  4 .       
 
         [0127]    The first element  91  can for example be a hook, and the second and third elements  92 ,  93  clamps able to maintain this hook. Many known locking alternatives can of course be adapted easily. 
         [0128]    Preferably, the locking is automatic, i.e., at the end of the course of tilting of the handlebar, the first element for locking  91  comes into contact with the second or the third elements for locking  92 ,  93 , and are engaged in the latter in order to have a locked state, without any other action from the user. 
         [0129]    The locking control  110 , placed at the rear or on a side of the backrest, acts simultaneously, in this embodiment, on two transmission cables  96  and  97  which respectively control the second and the third elements for locking  92 ,  93 . 
       5. Means for Fastening the Stroller in “Trailer” Position to the Bicycle 
       [0130]      FIG. 6  shows the stroller  61  of the invention, secured to a bicycle  62 . 
         [0131]    The means for fastening the stroller in “trailer” position to the bicycle are in particular shown in  FIGS. 7A to 7D . 
         [0132]    More precisely, means for fastening  71  are secured for example to the collar of the rod of the bicycle seat, by the intermediary of a clamping screw  711 . These means for fastening are for example intended to remain on the bicycle of the user. 
         [0133]    These means for fastening include, in the embodiment shown, a ball  712  in such a way as to allow for free movement of the hitch in relation to the bicycle during displacement such as in curves, moving over obstacles or unlevel surfaces. 
         [0134]    The handlebar  11  of the stroller tilted in “trailer” position is fixed to the means for fastening secured to the collar of the rod of the bicycle seat, by passing a finger  714  secured to the ball through the hole of the central section  163  of the handlebar detailed hereinabove, then folding back a closing flap  713  that can be mounted elastically, and/or which allows for a manual tightening of the latter in the closed position in order to prevent any disengaging of the handlebar from the bicycle seat. 
         [0135]    The means for fastening are for example universal means for fastening suited for any bicycle. As such, the fastening of the stroller in “trailer” position according to the invention to the seat of a bicycle is carried out rapidly without any tools or accessories. 
         [0136]    Furthermore, as indicated hereinabove no operation of removing the handlebar or the front wheels is required. 
         [0137]    To switch back to “stroller” position, it is sufficient to apply the inverse operations, namely:
       loosening the flap  713  of the means for fastening,   removing the ball from the means for fastening of the hole of the handlebar  11 ,   where applicable, unblocking the “trailer” position from the hinging node, for example by pressing a push-button, in order to allow both the tilting of the handlebar  11  and the deployment of the front wheel or wheels,   where applicable, blocking the hinging node in “stroller” position in order to secure the handlebar  11  in guiding position in order to guide the stroller.       
 
         [0142]    According to an alternative, shown in  FIG. 8 , the finger  714  can be replaced with a ball  81 , engaging with a complementary concave shape  82  provided for this purpose on the gripping area  16 . This approach also makes it possible for the bicycle to be able to lean over, with the two rear wheels of the trailer remaining in contact with the ground. 
         [0143]    According to another alternative, not shown, the means for fastening can further comprise an additional offsetting part, which can be removed, extending according to the direction of displacement of the bicycle. Such an additional fastening part makes it possible to offset towards the rear of the bicycle the attaching point of the handlebar (with respect to the attaching point shown in  FIGS. 7A to 7D  located in the vicinity of the means for fastening secured to the collar of the rod of the bicycle seat). 
         [0144]    Shifting towards the rear of the bicycle, with respect to the direction of displacement, of the attaching point of the handlebar, makes it possible to facilitate the clearance of the trailer, and therefore the driving comfort. 
       6. Folding of the Stroller 
       [0145]    So that the stroller is as compact as possible, the hinging node controls, and optionally blocks in a storage position, using means of blocking, both the handlebar in vertical position, directed skywards and substantially parallel to the backrest of the seat of the child, and also the complete stowing of the front wheel or wheels under or within a housing of the seat. 
         [0146]    As a complement, a reduction in the height of the handlebar can be carried out in this storage position, in particular by means of telescopic uprights  110 . 
         [0147]    In other embodiments, no particular folding is provided. 
       7. Other Characteristics and Advantages 
       [0148]    Many complements, alternatives and adaptations can be provided, with respect to the embodiment described, as suggested hereinabove, in particular with regards to the chassis, the damping, the seat or seats, the folding, etc. 
         [0149]    Means for braking can also be provided, in order to stop and immobilise the stroller, in particular in the “stroller” position. In this case, means for actuating the braking can be provided, automatically blocking the rear wheels during the tilting of the handlebar, for safety, and/or the front wheel or wheels, in the “trailer” position. It can also be provided, in this last position, means of controlling the braking, transferring a braking command from the rear wheel of the bicycle to at least one of the rear wheels of the stroller.