Patent Publication Number: US-2007110550-A1

Title: Straddle carrier

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention concerns an improved straddle carrier.  
      As is known, a straddle carrier is designed to be driven over a load so as to be able to lift this load and to move it to another location.  
      Straddle carriers are typically applied for moving and stacking containers.  
      2. Discussion of the Related Art  
      Such straddle carriers are already known which mainly consist of a mobile and controllable tire carrier which is formed of two parallel carrier elements on wheels onto which is provided a frame which can be adjusted in height and which is equipped with means for picking up said load.  
      Such straddle carriers are disadvantageous in that they are relatively large and high and not suitable to be moved or carried over long distances due to their construction and size.  
      If such straddle carriers do need to be moved, however, they are usually partly dismantled and taken to their destination by means of trucks or the like, where they are then assembled again.  
      It goes without saying that such movements are restricted to the very minimum and that, as a consequence, such straddle carriers usually stay where they are, in a harbor terminal or the like.  
      A disadvantage linked thereto is that such straddle carriers, given their relatively high cost and their restricted radius of action, are neither flexible, nor economical in use for smaller companies which need such straddle carriers only sporadically.  
      That is why such smaller companies generally do not use a straddle carrier, but rather a fork-lift truck or mobile crane, either or not rented, for handling containers.  
      It is clear that handling such containers with a crane lorry is less safe than using an adapted straddle carrier, as a result of which the risk of damages to the container and its content increases.  
      Moreover, renting a crane lorry is usually relatively expensive, and they have to be ordered in advance, which requires a very punctual planning.  
     SUMMARY OF THE INVENTION  
      The present invention aims to remedy one or several of the above-mentioned and other disadvantages.  
      To this end, the invention concerns an improved straddle carrier which mainly consists of a chassis with a mobile and controllable tire carrier which is formed of two mainly parallel longitudinal girders on wheels and a frame which can be adjusted in height provided on it, equipped with means for picking up a load, whereby the straddle carrier can be adjusted or folded up widthwise and is dimensioned such that it can be easily transported by a truck or wagon, or preferably even fits in a container when the chassis has been retracted or folded up widthwise and the frame has been lowered.  
      An improved straddle carrier according to the invention is advantageous in that it can be easily moved, preferably in a container, as a result of which it is far more flexible in use and purchasing it also becomes interesting for smaller companies.  
      Such a straddle carrier according to the invention preferably fits in a standard sea container, in particular a standard forty-feet sea container, such that use can be made of a generally available and widespread type of container for the straddle carrier&#39;s transport.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In order to better explain the characteristics of the invention, the following preferred embodiments of a straddle carrier according to the invention are given as an example only without being limitative in any way, with reference to the accompanying drawings, in which:  
       FIG. 1  schematically represents an improved straddle carrier according to the invention when operational;  
       FIG. 2  represents a view according to arrow F 2  in  FIG. 1 ;  
       FIG. 3  represents a view as that in  FIG. 3  while the straddle carrier is in use;  
       FIG. 4  represents the straddle carrier of  FIG. 1 , but in another position;  
       FIG. 5  represents the straddle carrier of  FIG. 1  in a situation in which it can be carried in a container;  
       FIG. 6  represents a variant of an improved straddle carrier according to the invention. 
    
    
     DESCRIPTION OF SOME PREFERRED EMBODIMENTS  
       FIGS. 1 and 2  represent an improved straddle carrier  1  according to the invention which mainly consists of a chassis  2  with a mobile and controllable tire carrier  3  which is mainly formed of two mainly parallel longitudinal girders  4  on wheels  5  and onto which is provided a frame  6  which can be adjusted in height, equipped with means  7  for picking up a load, in this case a container  8  represented as a dashed line, and a control cab  9  from where the movement of the straddle carrier  1  can be controlled and from where the straddle carrier  1  can be operated for picking up and putting down a load.  
      To this end, the straddle carrier  1  is provided with a source of energy, not represented in the figures, in the form of an engine which drives for example a hydraulic pump for the hydraulic drive and control of the straddle carrier  1  by means of for example hydraulic engines and cylinders.  
      The frame  6  is formed of two girders  10  which are connected to each other by means of two parallel or practically parallel cross beams  11 , and it is supported by means of double shears with two similar, adjustable shear mechanisms  12  which each rest on a longitudinal girder  4  of the tire carrier  3  and each support a girder  10  of the frame  6 .  
      Each shear mechanism  12  has two hinged parts  13  which hinge in relation to each other in a central hinge point  14  by means of a shaft  15 .  
      Each shear mechanism  12  is hinge-mounted to a longitudinal girder  4  of the tire carrier  3  and to a girder  10  of the frame  6  with two of its free ends,  16  and  17  respectively, situated on one side of the hinge point  14 , by means of the fixed shafts  18  and  19  respectively.  
      The two remaining far ends  20  and  21  of each shear mechanism  12  on the other side of the hinge point  14  are provided with a carriage or a trolley,  22  and  23  respectively, which are hinge-mounted to the far ends  20  and  21  concerned by means of shafts  24  and  25 , and which are provided in guides  26  and  27 , formed of two parallel ribs  28  on the top side of a longitudinal girder  4  and of two parallel ribs  29  with inwardly folded edges  30  on the lower side of a girder  10 , such that they can move in the longitudinal direction, shift in particular.  
      The above-mentioned frame  6  can be adjusted in height by means of one or two hydraulic or pneumatic cylinders which, in the given example, are vertically erected telescopic cylinders with several telescopic parts, whereby these cylinders  31  are provided between the tire carrier  3  and the frame  6 , but which can also be provided, according to an alternative embodiment  1 , between the tire carrier  3  and a shear mechanism  12  or between a shear mechanism  12  and the frame  6  or between the hinge-mounted parts  13  of a shear mechanism  12 .  
      Preferably, both shifting free ends  20  and  21  of each shear mechanism  12  are situated on one side of the above-mentioned central hinge point  14  of the shear mechanism  12  concerned, whereas the above-mentioned cylinder  31  is situated on the other side of the central hinge point  14 .  
      The straddle carrier  1  can be adjusted or folded up widthwise according to the invention, in other words in a direction crosswise to the driving direction.  
      In the specific example of the figures, this is realized as the frame  6  is a frame which can be folded widthwise, whereby the cross beams  11  are hinge-mounted to the girders  10  of the frame  6  by means of vertical shafts  32  with their far ends  33 .  
      The straddle carrier  1  is provided with a drive  34  for folding the straddle carrier  1  widthwise in the form of means which make it possible to fold the frame  6  widthwise by moving the two girders  10  crosswise in relation to each other, in particular by means of a hydraulic or pneumatic cylinder  35  which is hinge-mounted to a girder  10  or cross beam  11  with one far end  36  and which is hinge-mounted with its other far end  37  to another girder  10  or cross beam  11 .  
      In the case of  FIGS. 1 and 2 , the above-mentioned means  7  are formed of a spreader which is fit for handling containers  8  of different lengths and which, as is known, has telescopic parts  38  to this end which are provided in a central tubular part  39  suspended to the cross beams  11 , such that they can extend in the longitudinal direction of the straddle carrier  1 , whereby the telescopic parts  38  are provided with crosswise directed supporting arms  40  with appropriate suspension points  41  to pick up a container  8 .  
      The means  7  can preferably be adjusted or folded up widthwise as the supporting arms  40  are hinge-mounted to the telescopic parts  38 .  
      The use of a straddle carrier according to the invention is simple and as follows.  
       FIGS. 1 and 2  represent the straddle carrier  1  in its operational condition whereby the straddle carrier  1  is maximally unfolded widthwise and the frame  6  is situated in its highest position, whereby a container  8  is suspended to the frame  6  with the means  7 .  
      In this situation, the straddle carrier  1  can be moved so as to place the container  8  on a desired location, for example on the ground or, as is the case in  FIG. 3 , on another container  8 .  
      To this end, in the case of  FIG. 3 , the straddle carrier is driven over the other container  8 , and subsequently the telescopic cylinder  31  is gradually drawn in so as to stack the container  8  on the underlying container  8 .  
      After the means  7  have been uncoupled, the straddle carrier  1  can then be driven on to pick up the next container  8  from the ground or from the top of an underlying container and to move it.  
      While driving, the frame  6  can be lowered, either or not with a container  8  suspended to it, so as to maximally lower the centre of gravity of the straddle carrier  1  and thus improve the stability when taking a bend, which is advantageous in comparison with the conventional straddle carriers whose frame  6  cannot be adjusted in height.  
      According to the invention, the straddle carrier  1  is dimensioned such that, as is represented in  FIG. 5 , it fits in a container represented by means of a dashed line, in particular a standard forty-feet sea container  42 , when the straddle carrier  1  is folded up widthwise and the frame  6  has been lowered into its lowest position.  
      To this end, the telescopic cylinder  31  is entirely drawn in first until the frame  6  is in its lowest position, as is represented in  FIG. 4 .  
      Next, the supporting arms  40  are turned towards each other in the extension of the telescopic parts  38 , after which the cylinder  35  is drawn in, as a result of which the cross beams  11  will hinge in relation to the girders  10 , such that the girders  10  are drawn towards each other in a straddling manner so as to make the straddle carrier  1  narrower, such that the straddle carrier  1  can be driven in a forty-feet sea container so as to be moved to another, either not overseas location, without any additional dismantling or other actions being required, as is the case with the known straddle carriers.  
      It is clear that the height adjustment of the frame  6  and folding or drawing in the straddle carrier  1  widthwise can also be realized with other means than those represented in the figures.  
      Thus, one must not necessarily use a hydraulic drive, for example; also numerous other mechanical, pneumatic or electric actuators can be used.  
      Moreover, it is also possible to adjust the frame  6  in height in another way than by means of a shear mechanism.  
       FIG. 6  represents a variant of a straddle carrier according to the invention whose means  7  are fit for handling for example pipes  43  or tree-stumps or other loads.  
      It is also clear that the straddle carrier  1  can be controlled and operated in a teleguided manner.  
      The present invention is by no means restricted to the embodiments given as an example and represented in the accompanying drawings; on the contrary, such a straddle carrier according to the invention can be made in all sorts of shapes and dimensions while still remaining within the scope of the invention.