Abstract:
A method for storing an empty trailer chassis includes positioning a trailer chassis between a first and a second vertical storage rack and lowering first and second stabilizing beams along the vertical storage racks toward the trailer chassis. The first and second stabilizing-beam trolleys are attached to the respective first and second stabilizing beams and a spreader extends between the first and second stabilizing-beam trolleys. The spreader contains a chassis clamping mechanism that forms a downward-facing portion of the spreader. The chassis clamping mechanism is disposed below the first and second stabilizing beams. The method further includes engaging the trailer chassis with the chassis clamping mechanism. The first and second stabilizing beams are above the trailer chassis when the chassis-clamping mechanism has engaged the trailer chassis.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    This patent application is a divisional of U.S. patent application Ser. No. 13/359,119, entitled “Chassis Stacker” (Docket No. C0443/40558) filed Jan. 26, 2012, which is a continuation-in-part of U.S. patent application Ser. No. 13/175,526, entitled “System and Method of Handling Chassis” (Docket No. C0443/40558-0) filed Jul. 1, 2011, the disclosures of which are incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention pertains to a method for storing trailer chassis in general and, in particular, for stacking such trailer chassis. 
       BACKGROUND OF THE INVENTION 
       [0003]    Large container handling facilities such as ports or intermodal rail container yards require the ability to handle large quantities of trailer chassis in order to accept containers that must be transferred from storage stacks or rail cars to trucks for over the road travel to a final destination or, for possible repositioning within the handling facility. The storage and handling of empty chassis is an on-going, time consuming task for the container yard. 
         [0004]    In particular, the storage of empty chassis can take up an enormous amount of space. Furthermore, with empty chassis stored over a large area, considerable time is spent in locating and retrieving the empty chassis. Additionally, many facilities store chassis by leaning them against one another is a near vertical orientation. This results in frequent damage to the chassis and high annual repair costs. For these and other reasons, a system for improving the efficiency of the chassis handling task would be an important improvement in the art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    A method for storing an empty trailer chassis includes the step of positioning a trailer chassis between a first and a second vertical storage rack. The method further includes lowering first and second stabilizing beams along the vertical storage racks toward the trailer chassis. The first and second stabilizing-beam trolleys are attached to the respective first and second stabilizing beams and a spreader extends between the first and second stabilizing-beam trolleys. The spreader contains a chassis clamping mechanism that forms a downward-facing portion of the spreader. The chassis clamping mechanism is disposed below the first and second stabilizing beams. The method further includes engaging the trailer chassis with the chassis clamping mechanism. The first and second stabilizing beams are above the trailer chassis when the chassis-clamping mechanism has engaged the trailer chassis. The method further includes raising the first and second stabilizing beams so as to align the trailer chassis with an empty storage space in one of the first and second vertical storage racks. The method further includes traversing the first and second stabilizing-beam trolleys laterally along the respective first and second stabilizing beams such that the spreader is moved laterally between the first and second vertical storage racks so as to align the trailer chassis with the empty storage space. The method further includes lowering the trailer chassis onto a shelf member located in one of the first and second vertical storage racks. The method further includes disengaging the chassis clamping mechanism from the trailer chassis. The method further includes repositioning the spreader between the first and the second vertical storage rack. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of multiple chassis storage racks using one embodiment of an elevating structure. 
           [0007]      FIG. 2  is a perspective view of multiple chassis storage racks using one embodiment of an elevating structure. 
           [0008]      FIG. 3  is a perspective view showing a trolley mounted on a support rail. 
           [0009]      FIG. 4  is a perspective view showing a trolley mounted on a support rail. 
           [0010]      FIG. 5  is a perspective view showing a stabilizing beam trolley and drive system and chain used in one embodiment. 
           [0011]      FIG. 6  is a pictorial illustration showing the guide members in contact with the storage racks. 
           [0012]      FIG. 7  is a perspective view showing a spreader and stabilizing beam elevating structure used in one embodiment. 
           [0013]      FIG. 8  is a flow chart showing the steps associated with storing a chassis on a storage rack in one of the embodiments. 
           [0014]      FIG. 9  is a flow chart showing the steps associated with retrieving a chassis on a storage rack in one of the embodiments. 
           [0015]      FIG. 10  is a pictorial illustration of an end of the two chassis storage racks and a truck lane. 
           [0016]      FIG. 11  is a perspective view showing multiple chassis storage racks and a truck lane. 
           [0017]      FIG. 12  is a perspective view showing the chassis gripping member, used in one embodiment, attached to a chassis on the ground. 
           [0018]      FIG. 13  is a perspective view showing the chassis gripping member, used in one embodiment, elevating a chassis to a respective storage location. 
           [0019]      FIG. 14  is a perspective view showing the elevating structure with the chassis gripping device used in one embodiment in a retracted position. 
           [0020]      FIG. 15  is a perspective view showing the elevating structure with the chassis gripping device used in one embodiment in an extended position. 
           [0021]      FIG. 16  is an overhead view of the chassis stacker. 
           [0022]      FIG. 17  is a pictorial illustration of an elevation system used in one embodiment. 
           [0023]      FIG. 18  is a pictorial illustration showing the drive system used on an elevating structure in one embodiment. 
           [0024]      FIG. 18A  is a view of a motor and drive system used on an elevating structure. 
           [0025]      FIG. 18B  is a view of the pinions and common shaft used in the drive system on an elevating structure. 
           [0026]      FIG. 18C  is a perspective showing a rack and pinion drive system 
           [0027]      FIG. 19  is a flow chart showing the steps associated with storing a chassis on a storage rack in one of the embodiments. 
           [0028]      FIG. 20  is a pictorial illustration of a chassis gripping device and chassis contact members used in one embodiment. 
           [0029]      FIG. 21  is a pictorial representation showing the steps in which the chassis contact members contact a chassis. 
           [0030]      FIG. 22  is a perspective view showing the chassis being telescoped into place on the storage rack. 
           [0031]      FIG. 23  is a flow chart showing the steps associated with retrieving a chassis on a storage rack in one of the embodiments. 
           [0032]      FIG. 24  is perspective view showing an embodiment of a hoist system using a chain attached to a cylinder. 
           [0033]      FIG. 25  is a top view of a chassis stacker utilizing an embodiment of a hoist system using a chain attached to a cylinder. 
           [0034]      FIG. 26  is a side view of a chassis stacker utilizing an embodiment of a hoist system using a chain attached to a cylinder. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0035]    The following further illustrate the disclosure but, of course, should not be construed as in any way limiting its scope. 
         [0036]      FIGS. 1 and 2 , the chassis stacker  10  is comprised of a first and a second vertical storage rack  12 ,  14 . These first and second storage racks  12 ,  14  are displaced from one another by a first distance L 1  wide enough to accommodate a trailer chassis  15 , and connected at a top end  16  by a trolley rail support beam  18 . A rail-wheel mounted trolley  20  is positioned on the trolley rail support beam  18 , as shown in  FIGS. 3 and 4 . 
         [0037]    The trolley  20  has an elevation system  22  capable of raising and lowering a first and a second stabilizing beam  76 ,  78  that are suspended from the trolley  20 , as shown in  FIGS. 3-5 , and guided in their vertical motion by low-friction, storage-rack contact members  26 , as shown in  FIG. 6 , attached at respective first and second ends of each  80 ,  82  of the stabilizing beams  76 ,  78 . These contact members  26  are in contact with an inner surface  32  of the respective first and second vertical storage racks  12 ,  14 . 
         [0038]    A first and a second stabilizing-beam trolley  84 ,  86 , as shown in  FIG. 7  is attached to the, respective, first and second stabilizing beams  76 ,  78 , while a spreader  88  containing a chassis-clamping mechanism  90  extends between and attaches to the first and the second stabilizing beam trolley  84 ,  86 , as shown in  FIG. 7 . A drive system such as a drive chain  85  is used to move the stabilizing beam trolley  84 ,  86  along the stabilizing beam  76 ,  78 . As shown in  FIGS. 5 and 7 , the chain may be driven by a gearbox  79  which is driven by an electric or hydraulic motor  77 , which drives a chain sprocket  81 . The stabilizing beam trolleys,  84 ,  86  may also be self propelled by a motor and gearbox driving the trolley wheels. 
         [0039]      FIG. 8  shows a flow chart that describes what happens when using this embodiment to store an empty trailer chassis  15 . A trailer chassis  15  is positioned between the first and a second vertical storage rack  12 ,  14 . An operator then lowers on to the chassis  15  the first and second stabilizing beams  76 ,  78  which support a spreader  88  containing a chassis clamping mechanism  90 . The chassis clamping mechanism  90  is then engaged with the chassis  15 . Once the chassis  15  is securely engaged with the chassis clamping mechanism  90 , the first and the second stabilizing beams  76 ,  78  are raised so as to align the chassis  15  with an empty storage space in one of the first and second vertical storage racks  12 ,  14 . The spreader  88  is then traversed along the first and second stabilizing beams  76 ,  78 , through the use of the first and second stabilizing beam trolley  84 ,  86  so as to align the chassis  15  with the empty storage space. The chassis  15  is then lowered on to a chassis support member  52  located in one of the first and second vertical storage racks  12 ,  14 . Once the chassis  15  is securely positioned on the chassis support member  52 , the chassis  15  is disengaged from the chassis clamping mechanism  90  and the spreader  88  is repositioned between the first and the second vertical storage rack  12 ,  14 . The method of clamping the chassis is as shown in  FIG. 21 . 
         [0040]      FIG. 9  shows the process of retrieving an empty chassis  15  from a storage rack  12  using the stabilizing beam embodiment. During operation of this embodiment, the stabilizing beams  76 ,  78  are raised to the highest stored chassis  15 . The traverse spreader  88  is then lined up with the chassis  15  to be retrieved. Once aligned, the spreader  88  is lowered onto the chassis  15  where the chassis-clamping mechanism  90  then grips the chassis  15 . Once the chassis  15  is securely gripped, the chassis  15  is raised off of the chassis support member  52  and the spreader  88  is moved to center position between the two storage racks,  12  and  14 . After the spreader  88  is centered, the stabilizing beams  76 ,  78  and the spreader  88  are lowered along with the chassis  15  to the ground. When the chassis  15  is safely on the ground, the chassis-clamping mechanism  90  is released and the stabilizing beams  76 ,  78  and spreader  88  are raised to an elevated position, clear of the chassis  15  on the ground. 
         [0041]    In another embodiment, as shown in  FIGS. 10 and 11 , a chassis stacker  10  comprised of a first and a second vertical storage rack  12 ,  14  that are displaced from one another by a first distance L 1  that is wide enough to accommodate a trailer chassis  15 . The storage racks  12 ,  14  are connected at a top end  16  by a trolley rail support beam  18 . A trolley  20  is positioned on the trolley rail support beam  18 . In an embodiment, the trolley  20  is a rail-wheel mounted trolley  20 , as shown in  FIG. 10 . 
         [0042]    The trolley  20  has an elevation system  22  that is capable of raising and lowering an elevating structure  24  that is suspended from the trolley  20  and guided in its vertical motion by low-friction, storage-rack contact members  26  that are attached at respective first and second ends of the elevating structure, as shown in  FIG. 6 . These contact members  26  are in contact with an inner surface  32  of the respective first and second vertical storage racks  12 ,  14 . As shown in  FIGS. 12-13 , a chassis gripping device  34  is attached to the elevating structure  24  opposite the trolley rail  17 . As shown in  FIGS. 10, 14 and 15 , chassis gripping device  34  includes first and second chassis contact members  36 ,  38  that are telescopingly attached to the elevating structure  24 . A movable counter weight  44  is attached to the elevating structure  24  opposite the chassis gripping device  34  and proximal to the trolley rail  17 , while a drive system  46  is used to power the chassis gripping device  34  and the movable counter weight  44 . 
         [0043]    In an embodiment, the first and second storage racks  12 ,  14  are separated by a first distance L 1  of no less than 16 feet. 
         [0044]    The low-friction, storage-rack contact members  26  can be slide pads, rollers, or any suitable material or mechanism without departing from the spirit and scope of the invention. 
         [0045]    In an embodiment, each of the vertical storage racks  12 ,  14  is comprised of a first and a second vertical column  48 ,  50  displaced from one another, as shown in  FIG. 16 . Each one of said columns  48 ,  50  has a plurality of chassis support members  52  displaced vertically from one another and aligned with an opposing chassis support member  52  on the opposite column. In an embodiment, these chassis support members  52  are shelves, as shown in  FIGS. 10 and 11 . 
         [0046]    In an embodiment, as shown in  FIG. 17 , the elevation system  22  includes a hoist system  54 , and a motor  56  that powers a gearbox  58  that drives the hoist system  54 . In a more particular embodiment, the hoist system  54  includes a wire rope  60  wrapped around a hoist drum  62 , as shown in  FIG. 17 . In still another embodiment, the hoist system  54  includes a chain  55  attached to a cylinder  57 , as shown in  FIGS. 24-26 . In yet another embodiment, the hoist system  54  includes a vertical rack and pinion. 
         [0047]    In an embodiment, the counterweight  44  has a first weight, the telescoping structure and trailer chassis  15  combined have a second weight that is less than the first weight. 
         [0048]    In an embodiment, as shown in  FIG. 18  and  FIGS. 18A-C , the drive system  46  is a rack and pinion system that is comprised of a first pinion  64  having a first diameter D 1 , a second pinion  66  having a second diameter D 2  that is greater than the first diameter D 1  is mounted on a common shaft  68  with the first pinion  64 . In an embodiment as shown in  FIG. 18A , motor  67  turns a first drive sprocket  69  which causes a chain  71  to turn a second drive sprocket  73 . The turning of the second drive sprocket  73  rotates a shaft  68  which causes pinions  66  and  64  to rotate. A first rack  70  is mounted on the counterweight  44  so as to mesh with the first pinion  64 , while a second rack  72  is mounted on the chassis contact member and meshes with the second pinion  66 , as shown in  FIG. 18C . In such an embodiment, when the common drive shaft  68  rotates in a given direction, the first rack  70  moves in a first direction, and the second rack  72  moves in a second direction opposite the first direction. In another embodiment, as shown in  FIG. 18B , a motor  67  directly turns a common shaft  68 , thereby causing pinions  64  and  68  to rotate. 
         [0049]    The drive system  46  can be powered in various ways including hydraulically or electrically. The drive system  46  may also be comprised of a roller and chain. 
         [0050]      FIG. 19  shows a flow chart that describes what happens when the chassis stacker is in operation. As shown in  FIG. 10 , a trailer chassis  15  is positioned between a first and a second vertical storage rack  12 ,  14 . An elevating structure  24  having a chassis gripping device  34  is then lowered to the chassis where the chassis contact members  36 ,  38 , as shown in  FIGS. 14, 15, 20 and 21  engage the chassis  15 , as shown in  FIG. 13 . After the chassis  15  is securely engaged, the elevating structure  24  raises the chassis gripping device  34  and the chassis  15  so as to align the chassis  15  with an empty storage space in one of the first and second vertical storage racks  12 ,  14 , as shown in  FIG. 12 . Once aligned with the empty storage space, the chassis gripping device  34  extends the chassis  15 , as shown in  FIGS. 13 and 22 , into one of the first and second vertical storage racks  12 ,  14  where the elevating structure  24  then lowers the chassis  15  on to chassis support members  52  located in one of the first and second vertical storage racks  12 ,  14 . After the chassis  15  is positioned on the chassis support members  52 , it is disengaged from the chassis gripping device  34  which is then repositioned between the first and the second vertical storage racks  12 ,  14 . 
         [0051]      FIG. 23  shows the process of retrieving an empty chassis  15  that is already stored in a storage rack  12 . During such an operation, the elevating structure  24  is raised to the highest stored chassis  15 . Once aligned, the chassis gripping device  34  is extended to line up with the empty chassis  15 . The chassis gripping device  34  is then lowered to the chassis  15  and the chassis contact members  36 ,  38  grip the chassis  15 . Once the chassis has been securely gripped by the chassis contact members  36 ,  38  the chassis  15  is raised off of the chassis support members  52  and the chassis gripping device  34  is retracted to the center position where the chassis  15  is then lowered to the ground. Once the chassis  15  is on the ground, the chassis contact members  36 ,  38  are released from the chassis  15  and the chassis gripping mechanism  34  is raised to a high storage level. 
         [0052]    Although  FIGS. 8, 9, 19 and 23  show storing a chassis on the lowest available shelf and retrieving from the highest occupied shelf, the system could also be configured to store and retrieve from a specified location without departing from the scope and intent of the invention. 
         [0053]    All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
         [0054]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
         [0055]    Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.