Abstract:
A lift apparatus is provided for loading relatively items into the bed of a truck or van which initially lifts the item to the level of the truck bed and then is simultaneously loaded with the item onto the truck bed so that it can be used for unloading at the destination.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to lift apparatus, and, more particularly, to an apparatus for raising and lowering a load from one surface to another wherein the apparatus may be transported with the load. 
       BACKGROUND OF THE INVENTION 
       [0002]    The transport of items in the bed of trucks or the back of a van can present problems during both the loading and unloading operations. Motorcycles, all-terrain vehicles and other motor-driven equipment typically weigh several hundred pounds, and the most common means of loading these items into a truck bed or the back of a van is a ramp. Depending upon the height of the truck bed or van, the inclination of the ramp can be quite severe and it often takes two or three individuals to perform the loading and unloading operation due to the weight and bulkiness of such vehicles or equipment. Although motor-operated vehicles may be driven along a ramp, that practice can be dangerous and lead to personal injury and/or damage to the vehicle. 
         [0003]    Lift apparatus operated manually, pneumatically, hydraulically or by other means are commonly used to vertically move a variety of items. These devices are effective in loading and unloading vehicles and equipment in lieu of ramps, but one problem with current designs is that they are not portable. Unless there is a lift apparatus at the location where the vehicle or equipment is loaded, and then another one at the destination to assist with unloading, such apparatus are of limited use and application for the transport of relatively heavy vehicles and equipment in trucks, vans and the like. 
       SUMMARY OF THE INVENTION 
       [0004]    The lift apparatus of this invention provides a reliable means of loading relatively heavy vehicles or other equipment into the bed of a truck, van or the like which is portable and travels with such vehicles or equipment so that it can be used for unloading at the destination. 
         [0005]    In one presently preferred embodiment, the lift apparatus comprises a base having a number of rollers, a platform for supporting a vehicle, equipment or other load, and a lifting mechanism connected between the platform and base. The lifting mechanism is operative to move the platform and base between an extended position in which they are vertically spaced from another, and a retracted position wherein the platform and base are closely adjacent to one another. Two front supports having rollers at one end may be mounted to the front end of the platform, and two rear supports with rollers at one end may be mounted in a support position to the rear end of the platform when the platform and base are in the extended position. The platform also carries a ramp which may be extended from its rear end to assist with loading. 
         [0006]    The lifting mechanism of this invention operates by first placing the platform and base in the retracted position with the platform overlying the base and close to the level of a floor or other surface where the vehicle or equipment to be loaded is located. The ramp is extended and the vehicle or equipment may be easily loaded onto the platform. The lifting device is then operated to move the platform, and the vehicle or equipment is supports, vertically upwardly to the extended position. At this time, the two rear supports may be placed in the support position, i.e. extending vertically downwardly from the rear end of the platform. The rear supports may be provided with a threaded connection or other telescoping arrangement so that the roller at the lower end of each rear support engages the floor. The entire lift apparatus is then rolled to a position wherein the rollers of the two front supports engage a second surface, e.g. the bed of a truck, while the rollers of the two rear supports are in engagement with the floor. At this juncture, the lifting device is activated to move the base away from the floor, in a direction toward the platform, to the retracted position where the platform and base are located closely adjacent to one another. The lifting apparatus may then be rolled on the two front supports and the two rear supports toward the truck so that the rollers of the base engage the truck bed. When the base and platform are substantially entirely on the bed, the two rear supports may be removed from their support position. The reverse of the above-described operation is employed during the unloading operation. 
         [0007]    Unlike prior art designs, the lift apparatus of this invention is portable and may be transported with the vehicle, equipment or other object in the bed of a truck, a van or the like. The loading operation may be performed safely and easily because the platform is near the floor when in a retracted position, and the item may be readily unloaded at the destination using the same lift apparatus employed in the loading operation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The structure, operation and advantages of the presently preferred embodiment of this invention will become further apparent upon consideration of the following description, taken in conjunction with the accompanying drawings, wherein: 
           [0009]      FIG. 1  is a perspective view of the lift apparatus of this invention with the top plate of the platform removed; 
           [0010]      FIG. 2  is a side view of the lift apparatus with a ramp extended from the rear, a front support in place and a motorcycle located on the platform; 
           [0011]      FIG. 3  is a view similar to  FIG. 2  except with the platform in an extended position and a rear support coupled to the rear end of the platform; 
           [0012]      FIG. 4  is a view similar to  FIG. 3  wherein the lift apparatus is being rolled toward the bed of a truck and the roller of the front support in engagement with the truck tailgate; 
           [0013]      FIG. 5  is a view similar to  FIG. 4  depicting the lift apparatus being rolled into the bed of the truck; 
           [0014]      FIG. 6  is view similar to  FIG. 2  with the motorcycle in place on the lift apparatus, which is in the retracted position; 
           [0015]      FIG. 7  is a view similar to  FIG. 6 , except with the lift apparatus in the extended position; 
           [0016]      FIG. 8  is a view similar to  FIG. 7  wherein front and rear supports are depicted in place at the front and rear of the platform; and 
           [0017]      FIG. 9  is a view similar to  FIG. 8  showing a wheel mounted to the lift apparatus, and the front and rear supports removed, so that the lift apparatus may be utilized as a trailer to haul the motorcycle. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Referring initially to  FIG. 1 , a lift apparatus  10  according to this invention is schematically depicted. The apparatus  10  comprises a base  12 , a platform  14  and a lift mechanism  16  connected between the base  12  and platform  14 . As discussed in more detail below, the lift mechanism  16  is operative to move the base  12  and platform  14  vertically relative to one another between a retracted position in which such elements are located closely proximate to one another as depicted in  FIG. 2 , and an extended position shown in  FIG. 1 . For purposes of the present discussion, the terms “top,” “bottom,” “upper,” “lower,” “front,” “rear” and the like, refer to the orientation of the lift apparatus  10  as viewed in  FIG. 1 . 
         [0019]    The base  12  includes opposed side beams  18  and  20 , and opposed end beams  22  and  24 , that are connected at the ends to form a generally rectangular-shaped frame. A bottom plate  26  is connected to the beams  18 - 24  along their bottom surface to add rigidity to the base  12 . As depicted in  FIG. 2 , a number of rollers  27  are mounted to the bottom plate  26 . The platform  14  has a similar construction as that of the base  12 . The platform  14  has a generally rectangular-shaped frame defined by opposed side beams  28  and  30  and opposed end beams  32  and  34  that are connected to one another. A top plate  36 , shown in  FIG. 2 , is affixed to the top surface of the beams  28 - 34  for rigidity and to provide a surface for supporting a vehicle as described below. Preferably, both side beams  28  and  30  of the platform  14  are hollow with openings at the front end  38  and rear end  40  of the lift apparatus  10 , for purposes to become apparent below. 
         [0020]    As noted above, the lift mechanism  16  is connected between the base  12  and platform  14 . A scissors-type, hydraulically operated lift mechanism is depicted in  FIG. 1 , but it should be understood that other lifting devices and/or other drives, such as pneumatic, screw-operated etc., could be employed to move the base  12  and platform  14  between the extended and retracted positions and are considered within the scope of this invention. The lift mechanism  16  includes a first pair of scissor arms  42  and  44  and a second pair of scissor arms  46  and  48 , with both pairs pivotally connected at their centers. The upper end of each scissor arm  42  and  44  mounts a roller  50  that is movable in a longitudinal direction, e.g. front to rear as viewed in  FIG. 1 , along an upper track  52  mounted to the inside surface of side beam  30 . The lower end of each scissor arm  42 ,  44  is movable in the same fashion via a roller at the lower end thereof (not shown) along a lower track  54  mounted to the inside surface of the side beam  20  of base  12 . The scissor arms  46  and  48  are movable along tracks (not shown) mounted to the side beam  18  of base  12  and side beam  28  of platform  14  in the same manner as scissor arms  42  and  44 . As the upper and lower ends of the scissor arms  42 ,  44  and  46 ,  48  are moved toward one another the base  12  and platform  14  are moved vertically apart to the extended position shown in  FIG. 1 , and movement of such ends of the scissor arms  42 - 48  away from one another results in the base  12  and platform  14  moving to the retracted position illustrated in  FIG. 2 . 
         [0021]    The drive for lift mechanism  16  comprises a hydraulic cylinder  56  operatively connected to a pump  58  and a motor  60 . The pump  58  and motor  60  may be mounted to a plate  61  connected to the end beam  22  of base  12 . The housing of the cylinder  56  is mounted to a lower cross brace  62  connected between the lower ends of scissor arms  42  and  48 , and the piston  64  of the cylinder  56  is connected to a plate  66  supported by an upper cross brace  68  extending between the scissor arms  42  and  48 . Hydraulic fluid is supplied to the cylinder  56  by the pump  58  and motor  60  to extend and retract its piston  64 , and, in turn, extend and retract the scissor arms  42 - 48 , in the conventional manner. 
         [0022]    Referring now to  FIGS. 2-5 , the sequence of operation of the lift apparatus  10  of this invention is shown. For purposes of illustration, a motorcycle  70  is depicted as being loaded into the bed of a pickup truck  72 . Initially, the lift mechanism  16  is operated to move the lift apparatus  10  to the retracted position in which the base  12  and platform  14  are closely adjacent to one another near the level of the ground or floor  74 . A pair of front supports  76 , one of which is shown in  FIG. 2 , each has an upper end  78  that is inserted into the opening of the side beams  28  and  30  at the front end  38  of the apparatus  10 . The lower end of each front support  76  mounts a roller  82 . A ramp  84  may be provided to allow the motorcycle  70  to be rolled onto the top plate  36  of the platform  14 . Since the apparatus  10  is in the retracted position, the angle of the ramp  84  relative to the floor  74  is shallow and the motorcycle  70  may be easily loaded onto the platform  14  by a single individual. 
         [0023]    With the motorcycle  70  on the platform  14 , the ramp  84  may be removed. The lift mechanism  16  is then activated to move the platform  14  vertically upwardly relative to the base  12 , as shown in  FIG. 3 , so that the roller  82  of each front support  76  is at the same vertical height from the floor  74  as the bed and tailgate  73  of the truck  72 . Once in this extended position, a pair or rear supports  86  may be installed at the rear end  40  of the apparatus  10 . Each of the rear supports  86 , only one of which is shown in the Figs., comprises an upper section  90  having an insert  92  extending at a right angle to a threaded portion  94 . The threaded portion  94  is received within an internally threaded lower section  96  of the rear support  86 , and a roller  98  is mounted to the free end of the lower section  96 . Each rear support  86  is mounted at the rear end  40  of the apparatus  10  by placing the insert  92  into the opening in the side beams  28  and  30  of the platform  14 . Because the height of the bed of truck  72  and its tailgate  100  may vary from model to model, vertical adjustment of the rear supports  86  may be necessary to ensure that the rollers  98  contact the floor  74 . Such vertical adjustment is obtained by rotating the lower section  96  of the rear supports  86  relative to the threaded portion  94  of the upper section  90 . This may be done by hand or with a suitable tool (not shown). 
         [0024]    Referring now to  FIGS. 3 and 4 , with the front supports  76  in place at the front end  38  of the platform  14  and the rear supports  86  mounted at the rear end  40  such that their rollers  98  contact the floor  74 , the apparatus may be rolled along the floor  74  on the rollers  27  on the base  12  and the rollers  98  on the rear supports  86 . When the roller  82  of each front support  76  contacts the tailgate  73  of the truck  72 , all of the weight of the apparatus  10  is supported by the front supports  76  and the rear supports  86 . At that point, the lift mechanism  16  is activated causing the base  12  to move vertically upwardly relative to the platform  14  to a retracted position depicted in  FIG. 4 . The base  12  moves relative to the platform  14  because the platform  14  is held in place by engagement of the front supports  76  with the tailgate  73  and the rear supports  86  with the floor  74 . In this retracted position, the apparatus  10  may be rolled toward the truck  72  on the rollers  82  of the front supports  76  and the rollers  98  of the rear supports  86 . Once the base  12  reaches the truck  72 , its rollers  27  engage the tailgate  73  and roll along it into the truck bed. See  FIG. 5 . When the weight of the apparatus  10  is supported by the truck  72 , the rear supports  86  may be removed from the rear end  40  of the platform  14  allowing the apparatus  10 , and the motorcycle  70  it supports, to be entirely received within the truck bed. 
         [0025]    The loading process of this invention described above is simply reversed in order to unload the motorcycle  70  from the truck  72 . The apparatus  10  is moved toward the tailgate  73  until the rear supports  86  may be inserted into the side beams  28  and  30  of platform  14 , as discussed above, and such movement continues until the base  12  clears the tailgate  73  while the front supports  76  remain in contact with the truck bed or its tailgate  73 . See  FIG. 4 . At this juncture, the lift mechanism  16  is activated to cause the base  12  to move vertically downwardly into engagement with the floor  74 . With the weight of the apparatus  10  and motorcycle  70  now carried by the platform  14 , lift mechanism  16  and base  12 , the rear supports  86  and the front supports  76  may be removed. The lift mechanism  16  is then activated again to cause the platform  14  to move vertically downwardly into a retracted position relative to the base  12 , as depicted in  FIG. 2 . The motorcycle  70  may be unloaded from the apparatus  10  along the ramp  84  in the same manner as it was initially loaded. 
         [0026]    The lift apparatus  10  of this invention is therefore operative by first causing the platform  14  to move vertically upwardly relative to the base  12  when the base  12  is on the floor  74 , and then to move the base  12  vertically upwardly relative to the platform  14  when the platform  14  is in the extended position and supported at both ends by the front supports  76  and the rear supports  86 . Unlike prior lift devices, the lift apparatus  10  herein may be transported with the motorcycle  70  on the truck  72 , and then utilized to unload the motorcycle  70  at the destination to ensure both safe loading and unloading. 
         [0027]    Referring now to  FIGS. 6-9 , an alternative embodiment of this invention is shown in which the lift apparatus  10  is made to function as a trailer  100  which may be hooked to the truck  72  instead of requiring loading of the motorcycle  70  into the truck bed. The structure and operation of the lift apparatus  10  is the same as that described above in connection with a discussion of  FIGS. 1-5 , except as noted below. 
         [0028]    Initially, the motorcycle  70  is loaded onto the apparatus  10  in the same manner as described above and depicted in  FIG. 2 . The lift mechanism  16  is operated to move the platform  14  and motorcycle  70  vertically upwardly relative to the base  12  which is located on the floor  74 . See  FIG. 7 . With the scissor arms  42 - 48  extended as shown in  FIG. 7 , a pair of front supports  102  and a pair of rear supports  104  are inserted into respective openings in the side beams  28  and  30  of the platform  14  at the front end  38  and rear end  40  thereof. Only one of each of the front supports  102  and rear supports  104  is shown for ease of illustration. The front and rear supports  102 ,  104  have the same construction, and each comprises an upper portion  106  having an insert  108  joined with a threaded section  110 , and a lower portion  112 . The lower portion  112  is internally threaded to receive the threaded section  110  of the upper portion  106 , and a roller  114  is mounted at the free end of lower portion  112 . Vertical adjustment of the front and rear supports  102 ,  104  is obtained in the same manner as front and rear supports  76 ,  86  discussed above. 
         [0029]    With the front and rear supports  102  and  104  bearing the weight of the apparatus  10 , the lift mechanism  16  is activated to move the base  12  vertically upwardly to a retracted position relative to the platform  14  as shown in  FIG. 8 . A wheel assembly  116  may then be mounted to the base  12 . See  FIG. 9 . Front and rear supports  102 ,  104  may be adjusted vertically first to accommodate the height of the wheel assembly  116  to permit its installation, and then to lower the apparatus  10  downwardly onto the wheel assembly  116 . After the wheel assembly  116  is installed, the front and rear supports  102  and  104  may be removed from the platform  14  and the trailer  100  is thus complete. A hitch  118  may be provided at the front end  38  of the base  12  for connection to the truck  72 . The operations described above are simply reversed to convert the trailer  100  back to the lift apparatus  10  and unload the motorcycle  70 . 
         [0030]    While the invention has been described with reference to a preferred embodiment, it should be understood by those skilled in the art that various changes may be made and equivalents substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. 
         [0031]    For example, while a motorcycle  70  is shown in the drawings and described herein, it should be understood that the lift apparatus  10  of this invention may be used with essentially any vehicle or other object that may be transported by a truck, van or the like. Additionally, the lift apparatus  10  may be employed to transport an object from a first surface such as floor  74  to a vertically higher, second surface where there is no ramp, or where the ramp to such higher second surface is steep, or where the object has no rollers or other means to facilitate movement along a surface. Because the base  12  includes rollers  27 , an object placed on the apparatus  10  may be readily moved along essentially any surface and lifted upwardly and/or downwardly from one surface to another surface wherein such surfaces have different heights. 
         [0032]    Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.