Patent Publication Number: US-2022219960-A1

Title: Industrial truck

Description:
CROSS REFERENCE TO PRIOR APPLICATIONS 
     This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2020/056654, filed on Mar. 12, 2020 and which claims benefit to German Patent Application No. 10 2019 112 582.0, filed on May 14, 2019. The International Application was published in German on Nov. 19, 2020 as WO 2020/229020 A1 under PCT Article 21(2). 
    
    
     FIELD 
     The present invention relates to an industrial truck comprising opposing masts for lifting and lowering a loading platform which is located between the masts in a lifting and lowering direction, and a chassis that includes two lateral regions on which the masts are arranged. 
     The present invention in particular relates to an industrial truck which is used to transport air freight shipment pallets or containers. 
     BACKGROUND 
     Such an industrial truck has previously been described under the name “Xway Mover 7000” from the company DIMOS Maschinenbau GmbH. The chassis in this industrial truck is U-shaped and comprises a voluminous cross-bar which is usually arranged at the rear end in the forward travel direction and which connects the two lateral regions to each other. The loading platform in this vehicle can be lowered into regions close to the ground if it does not extend as far as the rear cross-bar. It is, however, generally desirable that loads to be transported, such as air freight shipment pallets or containers, can be pushed onto the loading platform not only from the front, but also from the rear. The loading platform must extend over the rear cross-bar for this purpose, as a result of which the minimum achievable loading and unloading height above the ground is undesirably high. 
     SUMMARY 
     An aspect of the present invention is to provide an industrial truck which has a comparatively low loading and unloading height at the front and at the rear. 
     In an embodiment, the invention provides an industrial truck which includes a loading platform, masts which are arranged opposed to each other, and a chassis. The masts are configured to lift and to lower the loading platform which is arranged between the masts in a lifting and lowering direction. The chassis comprises two side regions on which the masts are arranged, and at least two cross members which are arranged spaced apart from each other and which are configured to connect the two side regions with each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described in greater detail below on the basis of embodiments and of the drawings in which: 
         FIG. 1  is a first perspective view of an embodiment of an industrial truck according to the present invention; 
         FIG. 2  is a second perspective view of the same embodiment; 
         FIG. 3  is a side view of the same embodiment; 
         FIG. 4  is a view corresponding to  FIG. 2 , of the same embodiment, but loaded with a transport container; 
         FIG. 5  is a view from below of the same embodiment; 
         FIG. 6  is a view from above of the same embodiment; 
         FIG. 7  is a partial view of the same embodiment in a view according to  FIG. 1  from the rear; 
         FIG. 8  is a perspective rear view of a first embodiment of one of the two masts of the industrial truck according to the present invention; 
         FIG. 9  is a perspective front view of the mast shown in  FIG. 8 ; 
         FIG. 10  is a frontal view of the front of the same mast; 
         FIG. 11  is a view of the same mast from above; 
         FIG. 12  is a detailed view of a drive device of this mast; 
         FIG. 13  shows a machine element which is rotationally driven via the drive device and which interacts with a flexible pulling device; 
         FIG. 14  is a perspective rear view of a second embodiment of a mast; 
         FIG. 15  is a plan view of the front of the same mast; 
         FIG. 16  is a perspective front view of the same mast; 
         FIG. 17  is a perspective detail view of the upper region of a mast, and 
         FIG. 18  is a detail view of the central region of the embodiment of the mast shown in  FIGS. 14 to 16 . 
     
    
    
     DETAILED DESCRIPTION 
     In the case of the industrial truck according to the present invention, the chassis comprises at least two spaced-apart cross-bars which connect the lateral regions to each other. Due to the plurality of cross-bars now present, the cross sections of the cross-bars can be designed to be smaller than the single rear cross-bar of the industrial truck as described in the prior art. 
     The chassis of the industrial truck according to the present invention can, for example, be designed so that the cross-bars engage under the lateral regions. 
     The cross-bars are in particular, for example, arranged so as to extend in parallel with each other. 
     In a development, the cross-bars can, for example, each have a transverse extension which is greater than the overall height thereof. The minimum loading and unloading height can thereby be again reduced in the industrial truck according to the present invention. 
     It has been found that sufficiently high torsional rigidities can be achieved if the overall height is between 10% and 50%, for example, between 15% and 30%, for example, approximately 25%, of the transverse extension. 
     A development of the industrial truck according to the present invention provides that each cross-bar can, for example, comprise two struts extending in parallel with each other. These struts can then, for example, be connected to each other via a connecting plate in order to further increase torsional rigidity. 
     The struts can, for example, each have a rectangular, for example, a square cross section. 
     The connecting plate can, for example, further extend over the entire distance between the two lateral regions in order to again improve torsional rigidity. 
     The minimally achievable loading and unloading height can be further reduced if, for example, the loading platform has recesses for each of the cross-bars on the lower face thereof. 
     The present invention will be explained is greater detail below under reference to the accompanying drawings. 
     The embodiment of an industrial truck according to the present invention (hereinafter “industrial truck  100 ” for short) shown in the drawings comprises a chassis  1  having a loading region  2  which is delimited by side regions  3 ,  4 . Components (not visible in the drawings) which are required for the operation of the industrial truck, for example, energy stores such as fuel tanks and batteries, drive devices for driving and lifting functions, electrical and hydraulic circuits for controlling the driving and lifting performance in an open-loop or closed-loop manner and for steering the industrial truck, etc. are accommodated in the two side regions  3  and  4 . 
     In  FIG. 1 , the forward and reverse travel directions F, R are symbolized by the arrows F, R. 
     A driver&#39;s cab  5  is arranged in the front region of the left-hand side region  4 , as seen in the forward travel direction F. The driver&#39;s cab comprises the actuating device required for operating the industrial truck  100 , such as buttons, switches, joysticks, and a steering wheel. 
     As can be seen in particular in  FIG. 5 , the industrial truck  100  has four wheels, the front wheels  6  associated with the front axle A being designed as twin wheels, and the rear wheels  7  associated with the rear axle B being designed as single wheels. All of the four wheels are designed to be steerable so that they can be rotated through 360° about their relevant steering axle S. Each of the wheels  6 ,  7  is connected to its own steering motor (which is not shown in the drawings). All steering motors can, for example, be designed as electric motors and are controlled via a steering computer so that the industrial truck  100  can execute travel direction changes in any sequence without stopping. This means that a loading or an unloading station can be approached directly without complex maneuvering. 
     At least one of the front wheels  6  and rear wheels  7  is coupled to a travel drive. In order to improve traction, all of the front wheels  6  and rear wheels  7  can, for example, each be coupled to a travel drive. The travel drive(s), like the steering motors, can comprise electric motors. 
     As can be seen in  FIG. 5 , the chassis  1  has two cross-bars/cross members  8  which extend in parallel with each other and are arranged between the front axle A and the rear axle B. The cross members  8  connect the lateral regions  3  and  4 . The cross members  8  are arranged close to the ground and have a comparatively low overall height Y compared to the transverse extension X, so that a low loading and unloading height H can be achieved in the case of the industrial truck  100 , as is explained in greater detail below. 
     Two masts  9 ,  10  extend upward from the chassis  1 . The mutually facing sides of the masts  9 ,  10  are arranged so as to be at least almost flush with mutually facing sides of the side regions  3 ,  4 . 
     The two masts  9 ,  10  are used to lift and lower a loading platform  11  in a lifting and lowering direction Z. The loading platform  11  is used to carry a load, for example, a container C. Each mast  9 ,  10  has a flexible pulling device  12  therefor which revolves around a lower pulley  13  and an upper pulley  14 . In the shown embodiment, the flexible pulling device  12  comprises two V-belts which extend in parallel with each other. These V-belts are tensioned between the lower and upper pulleys  13 ,  14 , which are here provided as double belt pulleys. While the upper pulley  14  is mounted in a stationary bearing block  15  so as to be freely rotatable about an axis  16 , the lower pulley  13  is connected to the drive shaft  17  of a drive device  18  in a rotationally fixed manner. The drive device  18  can, for example, also comprise an electric motor. 
     The drive device  18  is mounted on a bearing block  19  which is arranged on the mast  9 ,  10  so as to be movable for the purpose of adjusting the tension of the flexible pulling device  12  (see in particular  FIGS. 12 and 13 ). The masts  9 ,  10  each have a bearing block receptacle  20  for this purpose which has a greater extension in the tensioning direction T than the bearing block  19 . According to  FIGS. 12 and 13 , two threaded bores, into each of which a clamping screw  21  is screwed, open into the bearing block receptacle  20  from above. The front end of each of the clamping screws  21  in the screwing-in direction is supported on a surface of the bearing block  19 . As is evident from  FIGS. 12 and 13 , the tension of the flexible pulling device  12  can be changed by screwing in and unscrewing the clamping screws  21 . 
     Due to the revolution around the lower and upper pulleys  13 ,  14 , the flexible pulling device  12  has two strands  22 ,  23  which extend in parallel with each other. In order for the flexible pulling device  12  of the two masts  9 ,  10  to rotate at exactly the same speed, the drive shafts  17  of the two drive devices  18  of the masts  9 ,  10  can, for example, be mechanically connected to each other via a connecting shaft  24  (see  FIG. 5 ). By providing a connecting shaft  24 , it is in principle also possible to provide only a single drive device  18  for the flexible pulling device  12  of the two masts  9 ,  10 . 
     For the purpose of lifting and lowering, the loading platform  11  is connected to one of the two strands  22 ,  23  of the two flexible pulling devices  12  of the masts  9 ,  10 , for example, to strand  23  in each case, which strands run in the same direction when the drive devices  18  are actuated. 
     In order to guide the loading platform  11  on the masts  9 ,  10 , guide profiles  25 ,  26  are provided on the masts  9 ,  10 , as can in particular be seen in  FIGS. 10 and 11  in the example of mast  9 . Each guide profile  25 ,  26  has an internal cross section which is approximately C-shaped. This cross section has a base surface  27  and two mutually parallel side surfaces  28 ,  29  which extend perpendicular from the base surface  27  to an open profile side  30 . 
     The guide profiles  25 ,  26  are arranged on the relevant mast  9 ,  10  so that their open profile sides  30  face each other. 
     As can be seen in  FIG. 11 , the loading platform  11  has two guide rollers  31 ,  32  on its side facing the mast  9 , which guide rollers  31 ,  32  in the shown embodiment each roll on one of the two outer lateral surfaces  29  of the guide profiles  25 ,  26  and thus guide the guide platform  11  to prevent movements relative to the mast  9  in the F-R direction of the industrial truck  100 . The loading platform  11  can of course also be formed correspondingly on the side (not shown in  FIG. 11 ) facing the other mast  10 . The mast  10  also has guide profiles  25 ,  26 . It should finally be noted that the guide rollers  31 ,  32  can also be arranged so that they both roll on the central side surfaces  28  of the guide profiles  25 ,  26 . Further guide rollers (not shown in the drawings) can also be provided which are offset in the longitudinal direction of the guide profiles  25 ,  26  with respect to the guide rollers  31 ,  32 , which further guide rollers in turn roll on one of the side surfaces  28  or  29 . The loading platform can as a result also be secured against tilting in an axis extending perpendicular to the plane of the drawing in  FIG. 10  via the guide profiles  25 ,  26 . 
     A significant advantage of the design and arrangement of the guide profiles  25 ,  26  and the guide rollers  31 ,  32  rolling therein is that forces acting on the loading platform  11  in the F-R direction, as can occur in particular during loading and unloading, are directly absorbed by the two masts  9 ,  10  and that no further, possibly technically complex, measures are required therefor. 
     As already mentioned above, the industrial truck  100  has a particularly low loading and unloading height H. As can be seen in  FIG. 7 , this is substantially identical on the front axle side and rear axle side. This is caused by the design of the chassis  1  with cross members  8  in contrast to the known U-shaped design of the chassis  1  with a single rear cross member  8  which, in order to achieve the required chassis rigidity, must have a considerably more voluminous cross section than the two cross members  8  which are spaced apart from each other in the longitudinal extension of the industrial truck  100 . In order to be able to minimize the loading and unloading height H, the loading platform  11  has recesses  33  for each of the cross members  8  on the lower face thereof, so that the loading and unloading height H only slightly exceeds the vertical extension of the cross member  8  from the ground. 
     Each of the cross members  8  can comprise two struts  34 ,  35  which extend in parallel with each other and which have a rectangular, for example, a square cross section. The struts  34 ,  35  are connected to each other by a connecting plate  36 . 
     As can be seen, for example, in  FIGS. 8 and 9 , the masts  9 ,  10  each have a base plate  37  from which a lower frame component  38 , which comprises the bearing block receptacle  20 , extends upward. The lower frame component  38  is approximately U-shaped when viewed from the front or the rear of the mast  9 ,  10 . Side walls  39 ,  40  of the mast, which are provided with lateral stiffening ribs  41 ,  42 , rest on the outer faces of the two legs of the lower frame component. A first main frame  43 , which comprises lateral profiles  44 ,  45  which are connected to each other via cross struts  46 ,  47 ,  48 , extends upward from the base plate  37 . Diagonal strutting  49 ,  50  which is arranged in an X-like manner extends between the lower cross strut  46  and the central cross strut  47 . The guide profiles  25 ,  26  are attached to the base plate  37 , the side walls  39 ,  40 , and the cross struts  46 ,  47 ,  48 . The so constructed mast is characterized by considerable torsional rigidity combined with low weight and low manufacturing costs. 
     In the embodiment of the mast shown in  FIGS. 8, 9 and 10 , the upper bearing block  15  is arranged between the central cross strut  47  and the upper cross strut  48 . As can be seen by comparison with the further embodiment of a mast  9 ,  10  shown in  FIGS. 14 to 18 , the bearing block  15  between the cross struts  47  and  48  is missing in this further embodiment. A second main frame  51  instead extends upward from the upper cross strut  48 . The second main frame  51  has a lower cross strut  52  which is screwed to the upper cross strut  48  of the first main frame  43 . A central cross strut  55  is connected to the lower cross strut  52  via diagonal strutting  53 ,  54 . The bearing block  15  is arranged between this central cross strut and an upper cross strut  56 . The guide profiles  25 ,  26  extend from the base plate  37  to the cross strut  56 ; the guide profiles  25 ,  26  are, for example, formed to be longer in the mast shown in  FIGS. 14 to 18  than the guide profiles shown in  FIGS. 8 to 10  by adding guide profile portions  57 . The flexible pulling device  12  accordingly also has a greater length in the embodiments shown in  FIGS. 14 to 18  than in those shown in  FIGS. 8 to 10 . 
     From the above explanations, it can be seen that, due to the modular design of the mast with a variable number of diagonal strutting and cross struts, it is possible to easily provide masts of different lengths that are adapted to user requirements. It can further be seen that, due to this modular design, existing industrial trucks having corresponding masts can be adapted to changing requirements with minimal effort with respect to the maximum lifting height that can be achieved therewith. For this purpose, only segments, as denoted by D in  FIG. 15 , together with the associated guide profile portions  57  of the relevant mast  9 ,  10  must be removed or added, and the flexible pulling device  12  must be replaced by one of a suitable length. 
     The present invention is not limited to embodiments described herein; reference should be had to the appended claims. 
     LIST OF REFERENCE NUMERALS 
     
         
         
           
               100  Industrial truck 
               1  Chassis 
               2  Loading region 
               3  Side region 
               4  Side region 
               5  Driver&#39;s cab 
               6  Front wheels 
               7  Rear wheels 
               8  Cross-bar/Cross member 
               9  Mast 
               10  Mast 
               11  Loading platform 
               12  Flexible pulling device 
               13  Lower pulley 
               14  Upper pulley 
               15  (Upper) Bearing block 
               16  Axis 
               17  Drive shaft 
               18  Drive device 
               19  Bearing block 
               20  Bearing block receptacle 
               21  Clamping screw 
               22  Strand 
               23  Strand 
               24  Connecting shaft 
               25  Guide profile 
               26  Guide profile 
               27  Base surface 
               28  (Central) Side surface 
               29  (Outer) Side surface 
               30  Open profile side 
               31  Guide roller 
               32  Guide roller 
               33  Recesses 
               34  Strut 
               35  Strut 
               36  Connecting plate 
               37  Base plate 
               38  Lower frame component 
               39  Side wall 
               40  Side wall 
               41  Stiffening rib 
               42  Stiffening rib 
               43  First main frame 
               44  Lateral profile 
               45  Lateral profile 
               46  Cross strut 
               47  Central cross strut 
               48  Upper cross strut 
               49  Diagonal strutting 
               50  Diagonal strutting 
               51  Second main frame 
               52  Lower cross strut 
               53  Diagonal strutting 
               54  Diagonal strutting 
               55  Central cross strut 
               56  Upper cross strut 
               57  Guide profile portion 
             A Front axle 
             B Rear axle 
             C Container 
             D Segment 
             H Loading and unloading height 
             S Steering axles 
             R Reverse direction of travel 
             T Tensioning direction 
             F Forward direction of travel 
             X Transverse extension 
             Y Overall height 
             Z Lifting and lowering direction