Abstract:
A sideloader forklift vehicle has a chassis supported on a plurality of wheels, a forklift mechanism supported on the chassis, an operator&#39;s cab supported on the chassis, and a battery cabinet supported on the chassis for electrically powering the sideloader forklift vehicle. The battery cabinet is elongated along a line parallel to the cab side edge of the chassis and has a cab side face located at a distance from the cab side edge whereby an operator within the operator&#39;s cab has a clear line of vision to a corner of the chassis defined by the cab side edge and the front end edge of the chassis. A side cabinet is provided between the cab side face of the battery cabinet and the cab side edge of the chassis, tapered in height from the cab to the front end edge of the vehicle chassis.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    This invention relates to a forklift vehicle. Particularly, this invention is directed to such a sideloader forklift vehicle having an electric motor drive. 
       BACKGROUND OF THE INVENTION 
       [0002]    In some warehouse operations, a sideloader forklift vehicle capable of maneuvering along and within a narrow aisle is used to retrieve and deposit loads, usually on multi-tier racks. 
         [0003]    An example of such a lift truck is a BAUMANN® ElectricFourway-Sideloader Series EVU 20/25/30 available from Baumann Handling Systems, Inc., of Yorkville, Ill., USA. U.S. Pat. No. 3,067,839 also describes a sideloader vehicle, herein incorporated by reference. 
         [0004]    A typical prior art electric sideloader forklift vehicle  20  is illustrated schematically in  FIGS. 1-3 . The sideloader includes four wheels  22 ,  24 ,  26 ,  28  that support a prone U-shaped chassis  32  from a floor surface. The chassis includes a longitudinally extended base  33  and laterally extended legs  34 ,  35 . The chassis  32  supports a hydraulic forklift assembly  36 . 
         [0005]    For purposes of orientation of the description herein, the chassis  32  has a front end  42  having a front end edge  42   a,  a rear end  44  having a rear end edge  44   a,  a rack side  46  having a rack side edge  46   a,  and a cab side  48  having a cab side edge  48   a.  The rack side  46  is the side which must approach a rack for loading and unloading articles passing across the rack side edge  46   a  using the forklift assembly  36 . A cab  52  is arranged on the base  33  along the cab side edge and along the rear end edge. Batteries  56  are arranged within a cabinet  57  arranged on the base  33  along the cab side  48  adjacent to the cab  52 . An end cabinet  58  for containing the electronics and hydraulics is provided adjacent to the batteries, along the cab side  48  and along the front end  42 . 
         [0006]    The cab side wheels  22 ,  24  are driven by motors  59 ,  60 . The cab side wheels are driven and steerable wheels such as described in U.S. Pat. No. 3,163,250. 
         [0007]    The forklift assembly  36  includes a frame-like mast  64  that supports a fork  66  having a longitudinally extended cross beam  67  and two laterally extended tines  68 ,  70  extending from the cross beam  67 . The cross beam  67  is guided for vertical movement on the mast  64  and supported vertically by a hydraulic cylinder  76  connected to the mast. The hydraulic cylinder  76  is used to selectively raise-and-lower the fork  66 . The fork  66  is shown supporting a load  78  being loaded onto, or unloaded from, a rack  82 . In this regard, the mast  64  is guided for horizontal translation on the chassis  32  by rollers (not shown) that move in guide tracks  90 ,  92  arranged in the legs  35 ,  36  of the chassis  32 . The mast is translated horizontally toward and away from the edge  46   a  by one or more hydraulic cylinders (not shown). 
         [0008]    In typical electric driven sideloader forklift vehicles, the batteries are located along the cab side of the sideloader forklift vehicle in order to make the sideloader forklift vehicle as narrow as possible to fit in narrow aisles laid out to effectively maximize warehouse storage space. For the same reasons, the cab is kept small, in many instances only allowing for a stand-up cab. Room for electric components, electronics, a hydraulic tank and the drive motor  60  is created at the opposite end of the cab, within the end cabinet  58 . 
         [0009]    The present inventor has recognized that this end location of the cabinet  58  blocks the batteries from being longitudinally slid out for replacement, which is preferred, and limits the battery changing process to a lift-out design. Also, the present inventor has recognized that the weight and relative high center of gravity of the batteries along the cab side of the truck makes this design more likely to tip over if the truck is turned too aggressively. 
         [0010]    In a typical loading operation in a warehouse, the forklift assembly of the sideloader forklift vehicle holds a large stack of elongated articles, such as lumber, which effectively blocks the operator&#39;s view of the rack on the rack side of the sideloader forklift vehicle. The operator must estimate the position of the sideloader forklift vehicle with respect to the rack by observing the position of the cab side of the sideloader forklift vehicle with respect to markings on the floor or external structures. When moving the vehicle within narrow aisles of a warehouse it is considered safe practice for the operator to keep his head within the cab. The present inventor has recognized that by keeping his head within the cab, it is difficult for an operator to estimate the precise position of the chassis given that the batteries are aligned longitudinally with the cab and due to the height of the batteries, the battery cabinet presents an obstacle to the operator viewing the location of the front lower edge of the chassis. 
       SUMMARY OF THE INVENTION 
       [0011]    The invention provides an forklift apparatus with an improved visual operability, improved safety features, improved stability and an improved operator&#39;s comfort. 
         [0012]    According to one aspect of the invention, a forklift vehicle comprises a chassis, a plurality of wheels, a forklift mechanism, an operator&#39;s cab, and an equipment cabinet. The chassis defines a rack side edge, a cab side edge opposite to the rack side edge, a front end edge, and a rear end edge opposite to the front end edge. The plurality of wheels supports the chassis from a ground surface. The forklift mechanism is oriented to load and unload elongated articles across the rack side edge of the forklift vehicle. The operator&#39;s cab is located along the cab side edge and the rear end edge of the forklift vehicle. The equipment cabinet is located along the cab side edge, the equipment cabinet having a tapered height from the operator&#39;s cab toward the front end edge, whereby an operator within the operator&#39;s cab has a clear line of vision to a corner of the chassis defined by the cab side edge and the front end edge. 
         [0013]    Preferably, the equipment cabinet extends from the operator&#39;s cab to the front end edge, the height of the equipment cabinet being linearly tapered from the operator&#39;s cab to the front end edge. Preferably, the equipment cabinet houses electronic and hydraulic components of the apparatus. 
         [0014]    According to another aspect of the invention, an electrically powered sideloader forklift vehicle has a chassis supported on a plurality of wheels, a forklift mechanism supported on the chassis, an operator&#39;s cab supported on the chassis, one or more electric motors driving one or more wheels, and one or more batteries supported on the chassis for electrically powering the electric motor or motors. The chassis defines a rack side edge, a cab side edge opposite to the rack side edge, a front end edge, and a rear end edge opposite to the front end edge. The operator&#39;s cab is located along the cab side edge and the rear end edge of the sideloader forklift vehicle. The batteries are arranged along a line parallel to the cab side edge, preferably within a battery cabinet, with a cab side face or sidewall located at a distance from the cab side edge whereby an operator within the operator&#39;s cab has a clear line of vision to a corner of the chassis defined by the cab side edge and the front end edge. 
         [0015]    An equipment cabinet can be located on the chassis between the cab side edge and the cab side face of the battery cabinet, the equipment cabinet having a tapered height from the operator&#39;s cab that end edge. The equipment cabinet can house electronic and hydraulic components of the apparatus. 
         [0016]    The equipment cabinet can extend from the operator&#39;s cab to the front end edge, the height of the equipment cabinet being linearly tapered from the operator&#39;s cab to the front end edge. 
         [0017]    Advantageously, only one electric drive motor can be used to drive one of the plurality of wheels and a distinct steering driver is operatively connected to each wheel of the plurality of wheels. 
         [0018]    Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, and from the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a schematic perspective view of a prior art sideloader forklift vehicle delivering a load of elongated articles onto a rack; 
           [0020]      FIG. 2  is a schematic top plan view of the sideloader forklift vehicle shown in  FIG. 1 ; 
           [0021]      FIG. 3  is a schematic side elevation view of the sideloader forklift vehicle shown in  FIG. 1 ; 
           [0022]      FIG. 4  is a schematic top plan view of a sideloader forklift vehicle of the present invention; 
           [0023]      FIG. 5  is a schematic side elevation view of the sideloader forklift vehicle shown in  FIG. 4 ; 
           [0024]      FIG. 6  is a schematic plan view of a steering system of the sideloader forklift vehicle shown in  FIG. 4 ; 
           [0025]      FIG. 7  is a schematic top plan view of an alternate embodiment sideloader forklift vehicle of the present invention; and 
           [0026]      FIG. 8  is a schematic side elevation view of the sideloader forklift vehicle shown in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
         [0028]      FIGS. 4 and 5  illustrate a sideloader forklift vehicle  100  of the present invention. Elements that are common to the prior art sideloader forklift vehicle described in  FIGS. 1-3  carry identical reference numbers. The forklift assembly  36  is not shown in  FIGS. 4 and 5  for simplicity but would be identical to that shown in  FIGS. 1-3 . 
         [0029]    The sideloader forklift vehicle  100  includes batteries  56  that are arranged in the cabinet  57  set back from the chassis cab side edge  48   a  The end cabinet  58  shown in  FIGS. 1-3  is replaced by a side cabinet  158  that is located adjacent to the edge  48   a.  The side cabinet  158  has a varying height “h” that is decreasing from the cab  52  toward the front end edge  42   a.    
         [0030]    According to the preferred embodiment, the height “h” decreases linearly, forming a tapered cabinet with a slanted cabinet top wall  160 . 
         [0031]    By tapering the cabinet  158  from the cab  52  to the front end edge  42   a,  the operator  53  has an unobstructed line of sight  166  to a top edge portion  168  of the front end edge  42   a,  without moving his head outside of the cab  52 . 
         [0032]    By observing this edge  168  that is close to the floor, the operator has a more accurate observation of the exact position of the chassis  32 . By knowing the position of the chassis  32  and by observing, for example, pre-applied floor markings or other pre-existing structure on the cab side of the sideloader forklift vehicle, the operator can more accurately position the sideloader forklift vehicle on the rack side thereof. 
         [0033]    Because the batteries  56  are relocated to a position that is between the rack side wheels  26 ,  28  and the cab side wheels  22 ,  24 , a more stable sideloader forklift vehicle is achieved, that is less likely to tip during aggressive turning. Also, because the end cabinet  58  of  FIGS. 1-3  is eliminated, the batteries  56  can be removed in a sliding fashion in the direction of the arrow  180 . A door or removable panel can be provided in the cabinet  57  for battery removal. A lifting operation and the use of a crane to remove the batteries for replacement are avoided. Additionally, because of the replacement of the end cabinet  58  with the side cabinet  158 , more plan area is available for the cab  52  to provide for operator comfort, i.e., a sitting cab with adequate legroom can be provided as opposed to a standing only cab arrangement. 
         [0034]    The side cabinet  158  is configured to contain the hydraulic, electric components and electronic components to drive the forklift vehicle  100  and the forklift  36 . 
         [0035]      FIG. 6  illustrates a four-wheel steering system  200  according to another aspect of the invention. The steering system  200  is described in more detail in co-pending patent application U.S. Ser. No. ______, filed on the same day as the present application, naming the same inventor, and identified by attorney docket number 6681P0020US, and herein incorporated by reference. 
         [0036]    The wheels  22 ,  24 ,  26 ,  28  can be driven, steerable wheels such as provided in the BAUMANN® Electric-Fourway-Sideloader Series EVU 20/25/30 available from Baumann Handling Systems, Inc., of Yorkville, Ill., USA or such as disclosed in U.S. Pat. Nos. 3,163,250; 3,698,504; 3,370,668; 4,461,367; 6,349,781; 6,367,571; or 6,854,552, all herein incorporated by reference. 
         [0037]    The steering system  200  includes a drive sprocket  22   a  for turning the cab side driven wheel  22 , a drive sprocket  24   a  for turning the cab side driven wheel  24 , a drive sprocket  26   a  for turning the rack side wheel  26 , and a drive sprocket  28   a  for turning the rack side wheel  28 . An idler sprocket  222  is arranged spaced from the drive sprocket  22   a.  An idler sprocket  224  is arranged spaced from the drive sprocket  24   a.  An idler sprocket  226  is arranged spaced from the drive sprocket  26   a.  An idler sprocket  228  is arranged spaced from the drive sprocket  28   a.    
         [0038]    A drive chain  222   a  is wrapped around the drive sprocket  22   a  and the idler sprocket  222 . A dual acting hydraulic cylinder  222   b  includes a cylinder portion  223   a,  a dual acting rod  223   b  that penetrates through the cylinder portion  223   a  and is connected at an intermediate position to a piston  223   c  within the cylinder portion  223   a.  The rod is exposed on opposite ends outside of the cylinder portion. The cylinder portion  223   a  is fastened to the drive chain  222   a.  The opposite ends of the rod  223   b  are fastened to stationary structure of the chassis  32 . Hydraulic fluid communicates through hydraulic lines  223   d,    223   e  into the cylinder portion  223   a  on opposite sides of the piston  223   c.  Depending on the differential pressure within the lines  223   d,    223   e,  the cylinder portion  223   a  will slide along the rod  223   b  in a selected direction. Movement of the cylinder portion  223   a  will cause circulation of the drive chain  222   a  in a selected direction. Circulation of the drive chain  222   a  will then cause turning of the drive sprocket  22   a  and turning of the wheel  22 . 
         [0039]    Each of the other drive sprocket and idler sprocket pairs  24   a,    224 ;  26   a,    226 ; and  28   a,    228  is wrapped by a respective drive chain and includes a hydraulic cylinder and an associated hydraulic circuit all arranged in the same configuration as that described above for the drive sprocket/idler sprocket pair  22 ,  222 . Operation of the hydraulic cylinders for turning the respective wheel  24 ,  26 ,  28  is the same as that described for turning the wheel  22 . 
         [0040]    All of the hydraulic lines, such as  223   d,    223   e,  are in fluid communication with a hydraulic valve network  230 . The valve network can be a solenoid-controlled spool valve manifold that is electronically controlled. The valve network receives pressurized hydraulic fluid from a hydraulic pump  234  and is in selective fluid communication with a low pressure return line to a hydraulic reservoir  238 . 
         [0041]    The hydraulic valve network  230  is in signal-communication with an electronic controller  242 . Electronic controller  242  receives as input signals the operator-selected traction direction, such as from a steering wheel  248  or like device and a direction selection lever  252 . 
         [0042]    The electronic controller is pre-programmed to convert the input signals to a corresponding output signal to the valve network to turn each of the four wheels  22 ,  24 ,  26 ,  28  to the correct angle. An example of a four-wheel steering control using an electronic controller controlling a hydraulic circuit to each wheel is described in U.S. Pat. No. 5,718,304 and is herein incorporated by reference. 
         [0043]    According to one aspect of the present invention, the present inventor has recognized that a single motor  60  ( FIG. 5 ) associated with drive wheel  24  is sufficient to drive the sideloader forklift vehicle under most circumstances. The further drive motor  59  can be eliminated while maintaining an effectively operable sideloader forklift vehicle. Therefore, the end cabinet  58  shown in prior art  FIG. 3  that accommodated the further drive motor  59  can be eliminated as well. A more compact side loader forklift vehicle is possible with the unobstructed driver&#39;s sight line  166 , given the relocation of the batteries  56  and the provision of the tapered side cabinet  158 . 
         [0044]      FIGS. 7 and 8  illustrate an alternate embodiment sideloader forklift vehicle  300  of the present invention. Elements that are common to the prior described sideloader forklift vehicles described in  FIGS. 1-6  carry identical reference numbers. The forklift assembly  36  is not shown in  FIGS. 7 and 8  for simplicity but would be identical to that shown in  FIGS. 1-3 . 
         [0045]    The sideloader forklift vehicle  300  also includes batteries  56  that are arranged in the longitudinally extending cabinet  57  that is set back from the chassis cab side edge  48   a.  The end cabinet  58  shown in  FIGS. 1-3  is replaced by a side cabinet  358  that is located along the edge  48   a.  Batteries  56  are also located within a laterally extended cabinet  357  that is adjacent the operator&#39;s cab  52  and along the edge  48   a  The side cabinet  358  has a varying height “h” that is decreasing from the cabinet  357  toward the front end edge  48   a.    
         [0046]    According to the preferred embodiment, the height “h” decreases linearly, forming a tapered cabinet with a slanted cabinet top wall  360 . 
         [0047]    By tapering the cabinet  358  from the cabinet  357  to the front edge  42   a,  the operator  53  has an unobstructed line of sight  166  to a top edge portion  168  of the front end edge  42   a,  without moving his head outside of the cab  52 . 
         [0048]    By observing this edge  168  that is close to the floor, the operator has a more accurate observation of the exact position of the chassis  32 . By knowing the position of the chassis  32  and by observing, for example, pre-applied floor markings or other pre-existing structure on the cab side of the sideloader forklift vehicle, the operator can more accurately position the sideloader forklift vehicle on the rack side thereof. 
         [0049]    Because the batteries  56  have an overall center of gravity that is relocated to a position that is between the rack side wheels  26 ,  28  and the cab side wheels  22 ,  24 , a more stable sideloader forklift vehicle is achieved, that is less likely to tip during aggressive turning. Also, because the end cabinet  58  of  FIGS. 1-3  is eliminated, the batteries  56  in the cabinet  57  can be removed in a sliding fashion in the direction of the arrow  180  and the batteries  56  that are located in the laterally extending cabinet  357  can be removed in a sliding fashion in the direction  380  ( FIG. 7 ). A door or removable panel can be provided in the respective cabinets  57 ,  357  for battery removal. A lifting operation and the use of a crane to remove the batteries for replacement are avoided. Additionally, because of the replacement of the end cabinet  58  with the side cabinet  358 , more plan area is available for the cab  52  to provide for operator comfort, i.e., a sitting cab with adequate legroom can be provided as opposed to a standing only cab arrangement. 
         [0050]    The side cabinet  358  is configured to contain the hydraulic, electric components and electronic components to drive the forklift vehicle  300  and the forklift  36 . 
         [0051]    From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred.