Patent Abstract:
The present invention provides an improved dolly which is not only effective in terms of return logistics but also simple in design and easy to use. The novel dolly includes a chassis, which has an upper side with a load carrying surface, and an opposing underside. The dolly also includes a tow bar, which is arranged slidably to the underside of the chassis via a pivoting mechanism, which is configured to pivot the tow bar about a horizontal axis. The chassis of the dolly includes a corresponding hitch, which allows pivoting action about a vertical axis between the tow bar and the hitch.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to European Patent Application No. 13159415.2, filed Mar. 15, 2013. 
       BACKGROUND 
       [0002]    The present invention relates to transporting goods. In particular, the invention relates to dollies, on which parceled goods are transported and stored temporarily. To be precise, the invention relates to a dolly according to the preamble portion of claims. 
         [0003]    There is known a vast variety of different devices used for transporting parceled goods. Typically pieces or stacks thereof are loaded onto a wheeled platform, on which they are conveyed to shop floor or storage. These wheeled platforms are called dollies. Some dollies are equipped with a tow bar and a corresponding hitch for transporting a plurality of dollies in a chained fashion. When the tow bar for pulling the dolly is temporarily not used, it is typically pivoted in an upright position for saving space. U.S. Pat. No. 4,856,810 proposes one solution to providing a space saving tow bar for a dolly. 
         [0004]    Conventional pivoting tow bars, however, occupy valuable space, when the dolly is in transit, for example. When the dolly is loaded onto a trailer such that the tow bar is not used for a long period of time, the folded tow bar uses excess space. This problem has previously been solved by providing couplings between the dolly and the tow bar, whereby the tow bar may be detached for transit. Detachable tow bars, on the other hand, are un-ideal for the reason that the detached tow bars must be handled separately and the coupling typically increases the complexity of the device and therefore reduces its robustness and user-friendliness required for logistics equipment. 
         [0005]    It is therefore an aim of the present invention to provide an improved dolly which is not only effective in terms of return logistics but also simple in design and easy to use. 
       SUMMARY 
       [0006]    The aim of the present invention is achieved with aid of a novel dolly for transporting items loaded thereon. The dolly includes a chassis which has an upper side with a load carrying surface, and an opposing underside. The dolly also includes a tow bar which is arranged slidably to the underside of the chassis via a pivoting mechanism which is configured to pivot the tow bar about a horizontal axis. The chassis of the dolly includes a corresponding hitch, which allows pivoting action about a vertical axis between the tow bar and the hitch. 
         [0007]    Considerable benefits are gained with aid of the present invention. 
         [0008]    By virtue of the slidable and pivotable connection between the tow bar and the chassis of the dolly, the tow bar may not only be guided to a towing and parking positions, the tow bar may also be guided to a retracted position. In the retracted position the tow bar is completely retracted under the load carrying surface of the dolly, wherein the external dimensions of the dolly are minimized for individual transport and storage of the dolly. 
         [0009]    Other objects and features of the invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are intended solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]    In the following, exemplary embodiments of the invention are described in greater detail with reference to the accompanying drawings in which: 
           [0011]      FIG. 1  presents an upper isometric view of a dolly with a tow bar in a towing position according to one embodiment. 
           [0012]      FIG. 2  presents an upper isometric view of the dolly of  FIG. 1  with the tow bar in a retracted position. 
           [0013]      FIG. 3  presents a lower isometric view of the dolly of  FIG. 1 . 
           [0014]      FIG. 4  presents a lower isometric view of the dolly of  FIG. 2 . 
           [0015]      FIG. 5  presents a lower isometric view of the dolly of  FIG. 1  with the tow bar raised to an upright position. 
           [0016]      FIG. 6  presents a top elevation view of the dolly of  FIG. 1 . 
           [0017]      FIG. 7  presents a cross-sectional view taken along the line B-B of  FIG. 6 . 
           [0018]      FIG. 8  presents a detail view of area C of  FIG. 7 . 
           [0019]      FIG. 9  presents an elevated frontal view of the dolly of  FIG. 1 . 
           [0020]      FIG. 10  presents a detail view of the pivoting mechanism denoted A in  FIG. 9 . 
           [0021]      FIG. 11  presents a rear bottom isometric view of the dolly of  FIG. 5 . 
           [0022]      FIG. 12  presents a detail view of the pivoting mechanism denoted A in  FIG. 11 . 
           [0023]      FIG. 13  presents an upper isometric view of two dollies as shown in  FIG. 1  being hitched to a dolly as shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The tow bar  120  of the dolly  100  according to the illustrated example may be guided into three main attitudes. In this context the term dolly is meant to refer to a cart-like dolly as described in engineering standard EN 12674-1.  FIGS. 1 ,  3  and  6  to  10  show the tow bar  120  in a substantially horizontal towing position, where the tow bar  120  is arranged to the first end  101  of the dolly  100  to be engaged with a hitch  190  of a towing dolly or tractor (cf.  FIG. 13 ). The dolly  100  as shown in the Figures may be an intermediate link in a chain of dollies  100 , but it may also serve as a tractor, wherein the handle  180  may be used to haul the combination of dollies. The handle  180  has substantially the shape of the letter A, wherein joints has been provided in the top region of the handle  180  for turning the top end of the handle  180  horizontally thus creating a gripping clearance for hands. 
         [0025]      FIGS. 5 ,  11  and  12  show the tow bar  120  in a substantially vertical position, where the tow bar  120  is arranged to the same first end of the dolly  100  but pivoted in an upright parking position. The parking position is used for short-term storage of the dolly  100 , whereby the tow bar  120  is turned into the vertical orientation for mainly safety purposes but also to save space. 
         [0026]      FIGS. 2 and 4  show the tow bar  120  in a retracted position, where the tow bar  120  is retracted from the first end  101  towards the opposing second end  102 . When in the retracted position, the tow bar  120  does not occupy the space in front of the first end  101  of the dolly  100  thereby saving crucial centimeters in the external dimensions of the dolly  100 . The retracted position is especially advantageous when dollies  100  are transported individually, i.e. not coupled to each other, in a trailer for example. As compared to the parking position, the tow bar  120  and the pivoting mechanism  130  are completely removed from the first end  101  of the dolly  100  resulting in the desired saving in the outer dimensions of the dolly  100 . 
         [0027]    Next, the construction according to one embodiment which enables this function is discussed in greater detail. 
         [0028]    As is the case with conventional dollies, the dolly  100  according the illustrated embodiment features a chassis  100  with a load carrying surface  113  for receiving said items. The load carrying surface  113  is considered to define the upper side  111  of the chassis  100 , whereas the castors and such are arranged to the opposing underside  112  of the chassis  100 . In the illustrated example, the load carrying surface  113  is uncovered, but according to an alternative embodiment, the load carrying surface  113  may have a veneer cover, a crate or similar tray for the loaded items. When the tow bar  120  is in the retracted position, it is covered by said load carrying surface  113 . 
         [0029]    As best shown in  FIGS. 3 to 5  and  11 , the dolly  100  includes a guide track  140  which is provided to the underside  112  of the dolly  100 . The guide track  140  runs in the main traveling direction of the dolly  100 , i.e. between the first and second end  101 ,  102  of the dolly thus connecting the front and rear of the dolly  100 . In the illustrated example, the guide track  140  is formed of two opposing profiles which are arranged at a distance from one another. The profiles of the guide track  140  are therefore separated by a distance which extends in the orthogonal horizontal direction in respect to the main traveling direction of the dolly  100 . The profiles of the guide track  140  exhibit a cross-section which have substantially the shape of the letter C. A portion of the guide track  140  nearest to the second end  102  of the dolly  100  is protected by a shield  160 , which is fixed to the underside  112  of the chassis  100 . 
         [0030]    The guide track  140  provides a running path for a tow bar assembly including the tow bar  120  as well as a guide block  150 , which is arranged to run in the guide track  140 , and a pivoting mechanism  130  which connects the tow bar  120  to the guide block  150  in a pivoting manner. Generally speaking, tow bar  120  is arranged slidably to the underside  112  of the chassis  110  via the pivoting mechanism  130  which, on the other hand, is configured to pivot the tow bar  120  about a horizontal axis. More precisely, the pivoting mechanism  130  is configured to be moved along the guide track  140  via the guide block  150  which is arranged slidably to the guide track  140 , namely between the two opposing profiles of the guide track  140 . The guide block  150  extends along the main traveling direction of the dolly  100 , i.e. along the guide track  140 , which has a stabilizing effect on the movement of the tow bar assembly. The guide block  150  according to the illustrated embodiment has been lightened to resemble the letter H for weight saving reasons. The function of the cooperation of the guide block  150  and guide track  140  is therefore to provide a stabile sliding connection between the tow bar  120  and the chassis  110  of the dolly  100 . While the guide block  150  is designed to remain in a fixed angular position in respect to the vertical axis, the angular movement between consecutive dollies  100  is provided between rotation between the hitch coupling  121  of the tow bar and the cooperating hitch  190 . 
         [0031]    According to an alternative embodiment (not shown), the guide is formed by means of a unitary profile shaped such as to receive the tow bar  120  in a similar sliding manner as the illustrated embodiment. In said alternative embodiment, the top of the profile is shaped to be attached to the underside of the dolly, wherein the inner surface of the profile is shaped to receive the guide block. Therefore the inner surface of the profile is adapted to receive the guide block in a sliding manner and the outer surface of the profile is adapted to provide a protective enclosure for the tow bar assembly including the tow bar, pivoting mechanism and the guide block. 
         [0032]    Turning now to  FIGS. 3 ,  5  and  7  to  12  which illustrate the construction and function of pivoting mechanism  130  connecting the tow bar  120  to the guide block  150  in a hinge-like manner. Fixed to the under surface of the guide block  150  are two distanced axle brackets  135  having aligned openings through which an axle  131  has been arranged to connect the brackets  135  in a horizontal direction transversal to the main traveling direction of the dolly  100 . The axle  131  therefore forms the axis of revolution of the tow bar  120 . A protective profile  161  is provided to the first end  101  of the dolly  100  to cover the pivoting mechanism  130  and to act as a fixing point for a hitch  190 . 
         [0033]    On the axle  131  a swing member  136  has been provided in a rotatable manner. The swing member  136  is connected to the tow bar  120  such that the tow bar  120  extends from the swing member  136  so as to allow the tow bar  120  to be pivoted about the axle  131 . The swing member  136  has a shape resembling the letter C, wherein the distal ends of the member feature male locking pieces  132  which are adapted to lock into to receptive openings  171  of a locking plate  170  which is provided to the first end  101  of the dolly  100  on top of the guide track  140 . Alternatively, the receptive openings  171  may be provided to beams or other structures making up the chassis  110  of the dolly  100 . The male locking pieces  132  are protuberances extending from the swing member  136  and form the male pieces of the locking interface between the swing member  136  and the locking plate  170  whose receptive openings  171  form the female counterpart in the locking interface. The swing member  136  is shown in the vertical position in  FIGS. 11 and 12 , wherein the tow bar  120  is in a vertical, i.e. upright position. When the tow bar  120  is pivoted into the horizontal towing position, the swing bar  136  is similarly rotated about the axle  131  into the horizontal position, wherein the male pieces  132  engage with the openings  171  of the locking plate  170 . In this configuration, the locking interface  132 ,  171  between the swing member  136  and the locking plate  170  ensure that the tow bar  120  does not slide backwards into the retracted position (cf.  FIG. 4 ). 
         [0034]    Referring now specifically to  FIGS. 10 and 12  which show that the pivoting mechanism  130  is configured to bias the tow bar  120  to an upright position about a horizontal axis transversal to the main traveling direction of the dolly  100 . More specifically, the swing member  136  is biased toward the horizontal position by means of a biasing spring  134  arranged around the axle  131  between the swing member  136  and the guide block  150 . With aid of the biasing spring the tow bar  120  is suspended such to create a tendency to pivot to the vertical position in order to aid the hitch coupling  121  at the distal end of the tow bar  120  to remain in contact with the cooperating hitch  190  ( FIG. 13 ). It is to be noted that the additional hitch seen in  FIG. 10 , for example, is not intended to couple to a hitch coupling  121  as seen on the tow bar  120  but to another coupling outside the scope of the present invention. 
         [0035]    The biasing spring  134  has an additional function. Once the tow bar  120  has been slid into the retracted position (cf.  FIGS. 2 and 4 ), the tow bar is biased upward, wherein the opening, i.e. the hitch coupling  121 , in the distal end of the tow bar  120  engages with a corresponding locking means  114  of the chassis  100 . The locking means  114  may, for example, be a protruding screw head of a screw used in the assembly of the chassis. The cooperation between the locking means  114  and the hitch coupling  121  is best shown in  FIG. 4 . 
         [0036]    The pivoting mechanism  130  further includes an angle limiting spring  133  which takes the form of an elastic conical stopper which protrudes orthogonally from the swing member  136  toward the second end  102  or guide block  150  of the dolly  100  depending on the angular position of the swing member  136 . The angle limiting spring  133  is configured to engage with the guide block  150  when the swing member  136  and particularly the tow bar  120  is pivoted into the horizontal position (cf.  FIG. 8 ). Once the angle limiting spring  133  has made contact with the guide block  150 , the angle of the tow bar  120  around the axle  131  and in respect to the chassis  100  is limited. Due to the compression elasticity of the angle limiting spring  133 , the terminal end of the tow bar  120  may be pressed downwards in order to fit the hitch coupling  121  to the cooperating hitch  190  ( FIG. 13 ). This downward orienting force on the tow bar side of the axle  131  is inverted into an upward orienting force at the angle limiting spring  133  on the opposite side of the axle  131 , wherein the angle limiting spring  133  compresses elastically thus providing suspended angular latitude for the tow bar  120 . The same function is used in on the one hand locking the hitch coupling  121  to the locking means  114  of the chassis  100  and on the other hand for releasing the hitch coupling  121  from the locking means  114  (cf.  FIG. 4 ). 
         [0037]    Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the method and device may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same results are within the scope of the invention. Substitutions of the elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale but they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Technology Classification (CPC): 1