Patent Publication Number: US-5289780-A

Title: Material handling railroad freightcar-mounted gantry and crane with toppling prevention and supplemental support upon derailment

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention is directed to a gantry with an attached crane mounted on a railroad freightcar and more particularly to a gantry and crane designed for handling large and bulky materials such as railroad tie bundles, rail culverts, poles, switches, etc. and loading or unloading them from the freightcar on which it is mounted or surrounding freightcars, and an apparatus and method for safely retaining the gantry on the freightcar. 
     2. Description of the Related Art 
     In modern railroad operations, it is common for railroad tracks, including rails, ties and ballast, to be replaced in large sections. This is often accomplished by special high capacity track renewal trains which include a number of railroad freightcars, each of which can accommodate large numbers of new ties, rails, culverts, etc. At least some of the freightcars in the train are equipped with a special pair of rails permanently affixed to the top thereof, and extending along each side of the freightcar. The special renewal train has at least one traveling gantry which can operate along the freightcar rails to transport material to or from the associated or surrounding freightcars. The gantry or gantries can be moved from car to car within the train as needed. 
     Such freightcar mounted gantries have supported both vertical hoists for lifting and transporting material along the cars, and power-driven cranes with extendable booms designed for considerable reach away from the cars. 
     A potentially dangerous problem associated with such prior art gantries, and particularly those supporting cranes, has been the tendency for tipping from side-to-side, given the necessarily high center of gravity of the crane and the large moment arm presented by the boom. In addition, operators of such gantries have had a tendency to drive them completely off of the rails on the freightcar, resulting in overturned and damaged gantries, and consequent danger to the operator and surrounding personnel. 
     It is clear, then, that a real need exists for a freightcar mounted gantry and crane which is designed to prevent these problems. Such a gantry should resist tipping and, in the event that either end is driven past the freightcar-mounted rails, the gantry should be prevented from overturning or otherwise falling off of the freightcar. For reasons of economy, such a gantry should be capable of accepting existing commercially available cranes. 
     SUMMARY OF THE INVENTION 
     In the practice of the present invention, a railroad freightcar-mounted gantry is designed to accept a commercially available crane. The gantry, which is designed to operate on dedicated rails extending along the outside edges of the freightcar, comprises a platform with four, separately drivable wheels. Extending above each rail and between the wheels on each side of the gantry is an elongated base support member which normally rides just above the rails. In the event that the wheels on either end of the gantry are accidentally driven past the end of the rails, the base support members drop down onto the top of the corresponding rails to support the gantry and prevent it from overturning and/or toppling off of the freightcar. Placed inside of the rails on each side of the freightcar is a corresponding pair of elevated safety rails. Each safety rail is attached to the corresponding rail via a plurality of welded support members. One or more J-hooks are rigidly attached to the gantry on the inside of each of the elongate base support members. The hook end of each J-hook overlaps a safety rail to prevent the gantry from tipping from side-to-side due to motion of the train or operation of the crane boom. Since all four wheels are powered, in the event that one end of the gantry is driven off of the rails, the wheels on the other end can be driven in reverse to pull the gantry back onto the rails. Other safety features include a separate parking brake for each wheel, and a wheel design with protected bearings and a covered drive mechanism. 
     OBJECTS AND ADVANTAGES OF THE INVENTION 
     The principle objects and advantages of the present invention include: to provide a railroad freightcar-mounted gantry and crane; to provide such a gantry and crane with four wheels designed to operate along rails mounted on the freightcar, with each wheel separately drivable; to provide such a gantry and crane in which an elongate base support member extends between the wheels on each side of the gantry to support the gantry in the event that the wheels on either end are inadvertently driven off of the rails; to provide such a gantry and crane in which one or more J-hooks attached to the base support members are positioned to engage a pair of elevated safety rails on the car to prevent the gantry from tipping from side-to-side; to provide such a gantry and crane which is designed for lifting and moving bulky and heavy objects safely and securely; to provide such a gantry and crane in which the wheels each include protected bearings and covered drive mechanisms; to provide such a gantry to which a commercially available crane can be attached; to provide a method of reliably securing a gantry to rails on a railroad freightcar which prevents the gantry from falling off of the end of the rails or tipping side-to-side; and to provide such a gantry and crane which is particularly well suited for its intended use. 
     Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. 
     The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a gantry and crane in accordance with the invention, shown mounted on a railroad flatcar. 
     FIG. 2 is an enlarged, fragmentary and cross-sectional view of the gantry, taken along line 2--2 of FIG. 1, with portions thereof broken away to illustrate a wheel drive mechanism, a J-hook and a safety rail. 
     FIG. 3 is an enlarged, fragmentary and cross-sectional view of the gantry, taken along line 3--3 of FIG. 2 and with portions of the safety rail broken away to illustrate detail thereof. 
     FIG. 4 is an enlarged, fragmentary view of a gantry wheel and base support member with the base support member partially broken away to illustrate the position of the base support member relative to the rail when the wheel is positioned on the rail. 
     FIG. 5 is an enlarged, fragmentary, cross-sectional view of the gantry, taken along line 5--5 of FIG. 4, and illustrating the position of the base support member relative to the rail when the wheel is positioned on the rail. 
     FIG. 6 is an enlarged, fragmentary view of a gantry wheel and base support member with the base support member partially broken away to illustrate the position of the base support member relative to the rail when the wheel has been driven off of the end of the rail. 
     FIG. 7 is an enlarged, fragmentary, cross-sectional view of the gantry, taken along line 7--7 of FIG. 6, and illustrating the position of the base support member relative to the rail when the wheel has been driven off of the end of the rail. 
     FIG. 8 is an enlarged and fragmentary cross-sectional view of the gantry, taken along line 2--2 of FIG. 1 and illustrating the J-hook engaging the safety rail to prevent the gantry from tipping side-to-side. 
     FIG. 9 is an enlarged and fragmentary exploded view of a gantry and a crane support post with an optional spacer illustrated in phantom lines. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     I. Introduction and Environment 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words &#34;upwardly&#34;, &#34;downwardly&#34;, &#34;rightwardly&#34; and &#34;leftwardly&#34; will refer to directions in the drawings to which reference is made. The words &#34;inwardly&#34; and &#34;outwardly&#34; will refer to directions toward and away from, respectively, the geometric center of the embodiment being described and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof and words of a similar import. 
     Referring to the drawings in more detail the reference numeral 1 in FIG. 1 generally designates a gantry and crane assembly adapted to operate along a pair of rails 2 positioned atop a railroad flatcar 3. A gantry 4 comprises four vertically oriented supports 5, each terminating in a flange 11. A crane 12, which can be a conventional, commercially available crane, also includes four mating vertical supports 13, each terminating in a flange 14. Referring to FIG. 9, the flanges 11 and 14 are connected together via a plurality of bolts 15 extending through cooperating bores 16 in the flanges 11 and 14 and secured by washers 20 and nuts 21. One or more spacers 22 can be provided between the flanges 11 and 14 to vertically adjust the crane 12. The crane 12 includes a conventional cab 23, a hydraulically operated boom 24 and an attached claw 25 for grasping and releasing materials. An operator 26 is positioned in a seat 31 with a control station 32 adjacent thereto. In a conventional fashion, the operator 26 can swivel the cab 23, control the boom 24 and the claw 25, and can operate the gantry 2 via the control station 32. The claw 25 is shown grasping a number of railroad ties 33 such as might be found on a track renewal train, for example. 
     II. Gantry 
     The gantry 4 will now be described, with reference to FIGS. 1-9. Referring to FIG. 1, the gantry 4 comprises four wheels 34, each of which supports one of the vertical columns 5. Each wheel 34 is independently drivable via a motor 35, a motor sprocket 41, a drive chain 42, and a wheel sprocket 43. Dynamic braking on each wheel 34 is via a conventional individual hydraulic brake system (not shown) which is enclosed and protected. Static braking, as when the railroad flatcar 3 is to be moved with the gantry and crane assembly 1 atop thereof, is accomplished via individual, hand-operated parking brakes 44. Each parking brake 44 includes a brake pad 51 pivotally connected to a lever arm 52 which is connected to pivot about a horizontal frame member 53. An adjustable linkage 54 extends through a corresponding vertical frame member 55 (FIG. 1), with an adjustment nut 61 adapted for tightening or releasing the linkage 54 and thus applying or releasing the parking brake 44. 
     Positioned above the rails 2 and between the wheels 34 on each side of the gantry 4 is a base support member 62. Each base support member 62 is constructed from a tubular steel member 63 and an inverted channel member 64. The channel members 64 are sized to extend over both sides of the rails 2, as shown in FIG. 5. Referring to FIGS. 4 and 5, the base support members 62 are normally positioned just above the rails 2, leaving a gap 65, when the wheels 34 are positioned on top of the rails 2. In the event that the operator 26 inadvertently drives the wheels 34 on one end of the gantry 4 off of the rails 2, the channel members 64 of the base support members 62 will fall onto the rails 2, eliminating the gap 65, as shown on FIGS. 6 and 7, supporting the gantry 4 to prevent it from falling off of the end of the rails 2 and/or toppling off of the railroad flatcar 3. 
     Referring to FIGS. 2 and 8, a safety rail 66 is attached to each rail 2 via a plurality of welded supports 71. A plurality of J-hooks 72 are welded or otherwise attached to the inside of the base members 62, with a hook end 73 of the J-hook 72 extending partially around the corresponding safety rail 66. Under normal conditions, the J-hooks 72 do not contact the safety rail 66, as shown in FIG. 2. In the event that the center of gravity of the gantry 4 is shifted significantly, as, for example when the boom 24 of the crane 12 is extended directly to the side with a heavy load, the gantry 4 will lean toward the boom 24. In such an event, the J-hooks 72 engage the safety rails 66, as shown in FIG. 8, and prevent the gantry 4 from tipping side-to-side. 
     Referring to FIG. 2, the drive mechanism for each wheel 34 is more particularly illustrated. Each wheel 34 resembles a conventional railroad wheel with an inner cylinder 74 riding on the rails 2 and sandwiched between a pair of outer plates 75. The wheels 34 rotate about enclosed bearing members 81 attached to axles 82, which are, in turn, attached to the vertical support posts 5 via opposing plates 83. The motors 35 and the motor sprockets 41 are attached to the vertical posts 5 via a mounting plate 84 secured by a plurality of bolts 85. Each bolt 85 is attached through a slot 91 which allows the support to be moved up and down via an adjustment screw 92 to adjust the tension of the chain 42. Each of the motors 35 are independently controllable in either direction by the operator 26 via cables 93, thus permitting a great deal of flexibility in driving the gantry 4. The motors 35 can be either electric or hydraulic. 
     III. Operation 
     The operation of the gantry and crane assembly 1 will now be described with reference to FIGS. 1-9. The flatcar 3 is one of a plurality of such cars on a train. The train can be a special track renewal train loaded with railroad ties, rails, culverts, ballast, etc. The gantry and crane assemblies 1 can be moved from car to car within the train to offload new track material and/or to load old track material. 
     Each gantry 4 is selectively movable forward and backward via the four, independently driven wheels 34. The concealed bearings 81 are virtually maintenance free and the placement of the wheel sprocket 43 on the inside of each wheel 43 adds to the safety of the gantry 4. The gantry 4 is securely held on the rails 2, even with the crane 12 operating, and even should the operator 26 inadvertently drive it off of the ends of the rails 2, by the J-hooks 72 cooperating with the safety rails 66, and by the base support members 62 overlying the rails 2, respectively. 
     In a preferred embodiment of the invention, the crane is a Komatsu PC80 removed from its drive tracks and equipped with the crane support posts 13 and flanges 14. 
     While the railroad car 3 is depicted herein as a flatcar, it should be clear that the rails 2 can be positioned on the bed of any suitable railroad freightcar, and, alternatively, can be placed on top of a box car with a strengthened frame. 
     It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.