Abstract:
The trailer comprises a rectangular framework, a loading box fixedly mounted on the framework and including a horizontal platform, and a group of freely rotatable carrying wheels which allow the trailer to be pulled. The trailer is characterized in that two frames are disposed underneath the framework and are arranged to engage one frame into the other one between an expanded position of the trailer where the frames are drawn apart from one another and a retracted position where the frames are drawn in towards one another. The framework holds the frames with supports, that are arranged to permit a simultaneous transverse and longitudinal movement of the frames with respect to the framework when said frames are moved between an expanded position and a retracted position.

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The invention concerns a trailer of the type in which the width can vary depending on specific needs. More particularly, the invention is directed to a trailer that is provided with a mechanism which enables to move apart the carrying wheels, while obtaining a loading box that can be expanded in the same proportions. 
     (b) Description of the Prior Art 
     The use of trailers hitched behind a vehicle often results in problems of width, specially with respect to small trailers that one would wish to place behind a small vehicle such as an all-terrain vehicle. Under these circumstances, one must turn to trailers of different widths, alternatively resort to a trailer that can be adjusted to different widths. 
     Structures that permit the expansion and the retraction of a trailer are known such as those described in the following US patents: 
     U.S. Pat. No. 4,221,398 
     U.S. Pat. No. 4,772,038 
     U.S. Pat. No. 5,249,823 
     U.S. Pat. No. 5,326,128 
     U.S. Pat. No. 5,332,276 
     However, these structures are all as much complicated as one another and do not permit the construction of a retractable and expandable trailer at a reasonable cost that is also easy to operate. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a trailer whose width can be modified if needed, that is not costly and is easy to adjust. 
     The present invention concerns a retractable and expandable trailer comprising a rectangular framework, a loading box fixed to the framework and including a horizontal freely rotatable carrying wheels enabling to pull the trailer. The latter is characterized in that there are provided two frames disposed under the framework and arranged to engaged into one another between an expanded position of the trailer where the frames are drawn apart from one another and a retracted position of the trailer where the frames are drawn nearer to one another, supports fixedly mounted on the framework, the framework holding the frames by means of the supports, the supports being arranged to permit a simultaneous transverse and longitudinal movement of the frames with respect to the framework when the frames are moved from an expanded position to a retracted position, the eanying wheels being respectively fixed to the two frames, and an articulation device permitting to move the frames by transverse and longitudinal sliding in the supports from an expanded position to a retracted position and vice versa, Longitudinal members adapted to juxtaposed the horizontal platform on both sides thereof in expanded position of the trailer. 
     Preferably, the trailer comprises a front panel rising from the front end of the rectangular framework, to join the vertical lateral panels and thereby constitute the loading box. 
     The rectangular framework preferably includes lateral sides; a rear side and a front side and a central link, fixed between the rear and front sides; the longitudinal members are each pivotally mounted along the lateral sides of the rectangular framework to adopt either a vertical position in retracted position of the trailer, where the longitudinal members and the panels abut one another; or, a horizontal position in expanded position of the trailer where the longitudinal members then constitute extension of the platform. 
     According to a preferred embodiment of the invention, each longitudinal member comprises a secondary panel perpendicularly fixed at one end of the longitudinal member thus constituting an extension of the front panel in expanded position of the trailer when the longitudinal member is in horizontal position; when the member is in vertical position, in the retracted position of the trailer, the secondary panel is positioned outside the front panel and against the latter, while each lateral panel rests on a corresponding longitudinal member, the latter then being in vertical position. 
     According to another preferred embodiment of the invention, the articulation device comprises a pivoting rod, that is articulated at one end along a leg of a frame and at the other end along a corresponding leg of the other frame, the pivoting rod being mounted on the framework, and enabling a 180° rotation of the rod causing a drawing in or drawing out of the frames between in the retracted and expanded positions, by articulation of the rotary rod with respect to the two legs on which it is articulated. 
     Preferably, the articulation device comprises two articulated rods, so that each leg of a frame is connected to a corresponding leg of the other frame. 
     According to another preferred embodiment of the invention, the trailer comprises a pivot pulley fixed to each of the articulated rods, at a location where the latter pivots on the framework, driving means provided for rotation of the two pulleys and thus causing a 180° rotation of each of the articulated rods, and consequently, drawing out or in of the two frames. 
     Each pivoting rod is preferably pivotally mounted on the central link of the framework. 
     According to another preferred embodiment of the invention, the trailer comprises a drawbar that is mounted on the framework, a transmission mounted on the drawbar, the transmission being operatively connected to each of the articulated rods, by means of the pivot pulleys. 
     Preferably, the trailer according to the invention comprises a support for each of the two legs of the two frames, the supports being shaped to define a rectangular opening capable of receiving one of the legs and permitting a transverse and longitudinal sliding of the legs in the supports. 
     According to another preferred embodiment of the invention, the transmission comprises a driving pulley as well as a crank in order to rotate the driving pulley. The pivot pulley and the driving pulley are preferably sheave wheels which are functionally connected to one another by means of a system of straps. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood with reference to a preferred embodiment given by way of example and without limitation of the scope of the invention, said preferred embodiment being illustrated by means of the annexed drawings, in which 
     FIG. 1 is a perspective view taken from underneath a trailer according to the invention, illustrating the mechanism that permits the expansion and the retraction of the trailer; 
     FIG. 2 is a perspective view showing the trailer in expanded position; 
     FIG. 3 is a schematic view in perspective illustrating a longitudinal pivoting member used to complete the platform when the trailer is in expanded position; 
     FIG. 4 is a schematic cross-section view showing the longitudinal member in a horizontal position to complete the platform when the trailer is in expanded position; 
     FIG. 5 is another schematic view illustrating the longitudinal member while being raised by pivoting when the trailer adopts a retracted position; 
     FIG. 6 is a schematic section view showing the longitudinal member in contact with the lateral wall of the loading box, when the trailer is in expanded position; 
     FIG. 7 is a schematic view illustrating the mechanism used to expand the trailer, in retracted position; 
     FIG. 8 is a view similar to FIG. 7, in an initial intermediate expanded position; 
     FIG. 9 is a view similar to FIG. 7, in an advanced intermediate expanded position; and 
     FIG. 10 is a view similar to FIG. 7, in a final expanded position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the drawings, it will be seen that a trailer according to the invention first consists of a framework  1  that is generally rectangular, and carries two movable frames  3  and  5 , on which carrying wheels  7  and  9  are mounted, by means of freely rotatable cylinders, respectively  11  and  13 , held to the frames by means of suitable supports  15  and  17 . 
     More specifically, rectangular framework  1  includes lateral sides  19 ,  21 , a front side  23 , a rear side  25  as well as a central link  27  that is fixedly mounted in known matter such as by welding, between front and rear sides  23 ,  25  as well illustrated in the drawings particularly FIG.  1 . To draw the trailer, there is provided a drawbar  29  that is fixedly mounted on front side  23  of rectangular framework  1 , said drawbar thereby constituting a continuity of central link  27 , as illustrated. Finally, the rectangular framework comprises four supports  31 ,  33 ,  35  and  37  in the shape of a rectangular U shaped members whose specific shape and characteristics will be described in detail herein bellow. 
     One of the essential characteristics of the invention is the presence of two movable frames  3  and  5  which will now detailed. The two frames  3 ,  5  being identical, only one will be described in details, i.e. frame  3 . Frame  3  generally appears as a U shaped member, including a base  39  and two legs  41  and  43  which are parallel with one another and perpendicular to base  39 . To give a satisfactory stiffness to frame  3 , there is provided an oblique member  45 , connecting base  39  to leg  41 . Frame  5  being identical to frame  3 , it will be sufficient to identify its corresponding components by means of reference numerals. It will therefore be seen that frame  5  includes legs  47 ,  49 , base  51  and a oblique reinforcement member  53 . 
     As described above, carrying wheels  7  and  9  are fixedly mounted on the two frames  3  and  5 , i.e. by means of supports  15  and  17  and freely rotatable cylinders  11  and  13 . As seen in the drawings, support  15  is mounted on a plate  54 , that is welded to frame  3  at the level of base  39  and oblique member  45 . Similarly, support  17  is mounted on a plate  56  that is welded to frame  5  on base  51  and oblique member  53 . It will be noted here that the trailer includes a loading box  87  primarily made of a horizontal platform  89 , fixed in known manner to framework  1 , and vertical lateral panels  91 ,  93 , preferably fixedly mounted on bases  39  and  51  respectively of frames  3  and  5 . To complete loading box  87 , there are provided vertical front and rear panels  95  and  97  that are fixedly mounted in known manner to front and rear sides  23  and  25  of the framework. The pieces used to complete the loading box when the trailer is in expanded position will be discussed later. 
     Obviously, in order that the two frames  3 ,  5  be operative, frames  3 , 5  must be held to framework  1  and underneath framework  1 . To achieve this, it should be understood that the two frames are connected together by means of an arrangement which will be discussed later and which is arranged so that the two frames constitute one single assembly. To hold this assembly, there is provided a group of four U shaped support units  31 ,  33 ,  35  and  37 , as mentioned above which are all identical to one another and are fixedly mounted in a rigid manner to framework  1 . More specifically, each U shaped support unit comprises two downwardly directed vertical tongues  55 ,  57  which are fixed such as by welding or in any other manner to framework  1 , on the lateral sides  19 ,  21  of the latter, as illustrated in the drawings. The base of each U-shaped unit, on the other hand, consists of a metallic rod  59  that is parallel to the corresponding lateral sides  19 ,  21 , and that connects vertical tongues  55 ,  57  so as to provide a rectangular space  61  whose dimension are such that a leg  41 ,  43 ,  47  or  49  can longitudinally and transversally slide therein in the direction indicated by arrows  63  and  65 . 
     We will explain later that the two frames  3  and  5  are movable with respect to one another. An articulation mechanism that will be described herein enables to expand or retract the two frames  3  and  5  with respect to one another. Rectangular spaces  61  have been provided at the level of the U-shaped units  31 ,  33 ,  35  and  37  to provide for this relative movement of the two frames. 
     The articulation, enabling the two frames to expand or to retract, depending on specific needs will now be described. It will first be seen that the two frames  3 ,  5  are arranged to penetrate one another at the level of their Legs  41 ,  47  and  43 ,  49  and that these are adjacent by pairs i.e. pair  41 ,  47  and pair  43 ,  49 . To achieve this, there is provided an articulation mechanism characterized in that at the meeting point between each pairs of legs  41 ,  47  and  43 ,  49  there is provided a pivoting rod  67  that is pivotally mounted on central link  27 , in the central portion thereot at  68 . It will be noted that to simplify the description, the two pivoting rods are identified by the same reference numeral, such as  67 . 
     To still simplify the description, we will restrict the description to pivoting rod  67  which connects legs  41  and  47 , it being understood that the other pivoting rod  67  which connects legs  43  and  49  is identical and mounted in the same manner between legs  43 ,  49 . 
     Underneath the surface of legs  41 ,  47 , at a point located at a short distance of the free end of each of the two legs, there are fixedly mounted, such as by welding or any other manner known to one skilled in the art, connections in the form of short bands  69 ,  71 . Pivoting rod  67 , on the other hand, is fixed at its two ends to bands  69 ,  71 , by means of pivot joints  73 ,  75 . The possibility of allowing pivoting rod  67  to rotate up to 180° at  68 , in one direction or the other and the presence of articulations at  73 ,  75  enables the two frames to retract or expand between an expanded position and a retracted position as clearly illustrated in FIGS. 7 to  10 . This operation will obviously produce a simultaneous longitudinal and transversal movement of legs  41 ,  47  and  43 ,  49  in rectangular space  61  according to arrows  63  and  65  as mentioned above. 
     The articulation about pionts  73 ,  75  and the pivoting movement about point  68  are made possible by means of a combination of pulleys  77 ,  79  and  81  and driving belts  83  and  84  that will know be described. Pulleys  77  and  79  are operatively welded in known manner on pivoting rods  67  as seen in the drawings, these two pulleys  77 ,  79  being connected together by means of driving belt  83 . To complete the operation of pulleys  77 ,  79 , there is provided a transmission box  85 , mounted in known manner on drawbar  29  and connected also in known manner to a crank shaft  88  and pulley  81 . Driving belt  84  connects pulley  81  to pulley  79 . 
     To expand or retract movable frames  3  and  5 , and consequently carrying wheels  7  and  9  and vertical lateral panel  91 ,  93 , it is merely sufficient to use the crank  88  in one direction or the other, thereby driving the two pulleys  77 ,  79  and causing the two pivoting rods  67  to pivot up to 180°. To provide an expanding movement, it will be seen that the articulation of rod  67  and the longitudinal and transverse movements of legs  41 ,  43 ,  47  and  49  will cause frames  3  and  5  to adopt the expanded position. Reversely, during the operation of the crank in the opposite direction, and always according to longitudinal and transverse movements, there will be a narrowing of the two frames, until reaching the retracted position of the trailer. Reference will made particularly to FIGS. 1 and 10 for and illustration of this operation. 
     When the trailer is in the expanded position, there is obviously something missing at the level of the platform. To overcome this absence, there are provided longitudinal members  99 .  101  that are pivotally mounted respectively along lateral side  19  and  21  of framework  1 . With reference to FIG. 4, it will be seen that in a vertical position, longitudinal member  99 ,  101  constitutes one side of the loading box by resting against lateral panel  91 . However, in a horizontal position, as seen in FIG. 6, the longitudinal member  99 ,  101  now completes platform  89  of the loading box  87 . 
     Referring now to FIGS. 3 and 4, it will be seen that each longitudinal member  99 ,  101  comprises a secondary panel  103  that is perpendicularly fixed to one end of the latter to constitute and extension of front panel  95  when the trailer is in the expanded position and longitudinal member  99 ,  101  is horizontally mounted along platform  89 . On the other hand, in the retractedelesed position of the triler, secondary panel  103  is folded exteriorly and against front panel  95 . A second secondary panel will be provided, in the case where the loading box also comprises a rear panel  97 . 
     It is understood that according to the invention modifications to the preferred embodiment that has be described are possible, of course, provided that these modifications are within the scope of the appended claims.