Gantry cranes are widely used throughout the world to move heavy equipment within warehouses and storage yards and to load and unload freight vehicles. The gantry cranes have overhead beams on which trolleys with cable winders, sheaves and hooks ride on wheels from side to side to raise, lower and laterally move loads. Carriages are usually provided at the bottoms of legs which support the beams. The carriages move the gantry cranes along a floor or on tracks to approach, lift, reposition and deposit loads as cable winders on the trolleys are activated and the carriages are moved.
Existing gantry cranes are cumbersome and are difficult to move between locations, and cranes are heavy and are difficult to transport to locations and to erect at the locations because of the great weight that is required to provide the strength of the cranes. Lightweight cranes are unsuited for lifting significant loads.
Needs exist for new and improved gantry cranes.
The new gantry crane is transportable in sections and is easily erected and bolted together at five points. The crane is strong and rigid, and is designed to withstand operational load stresses and to compensate for irregularities in the tracks on which it rolls while in operation.
A load bearing I-beam is at the bottom of an inverted triangular cross-section truss. Angularly, related gussets in the truss are connected at their bottoms to plates welded to the I-beam. Tops of the gussets are connected to plates welded between pairs of two longitudinally extended oppositely oriented angle irons on both sides of the top of the inverted triangular truss. The pairs of opposite angle irons operate as rigid X-beams. Angularly oriented angle irons extend across the top. Their ends are connected to plates which are welded to the X-beams. Legs of the crane are pipes connected to cross-plates at the ends of the X-beams. One end has additional outward sloping triangularly arranged outrigger legs which are connected to a sloped plate at a cantilevered end of the main beam. At the other end of the crane, vertical plates are welded at the tops of the pipe legs and are bolted to the end cross plate on the X-beams. The vertical plates at the top of the legs provide limited flexibility for accommodating floor and rail irregularities.
A gantry crane has a rigid open three-dimensional truss cross-beam. A lower I-beam and parallel upper X-beams are interconnected with angular gussets and angle irons forming a triangular open beam truss bounded by three trusses. Angular gussets on the sides are formed as parallel members to provide maximum strength. One end support is rigid, with upper ends of legs having plates bolted to a first end plate extending between the X-beams. Outrigger legs have an upper plate bolted to a sloped plate at an extended end of the I-beam. Vertical support legs at the other end have a strengthening cross-member and upper vertical plates which are bolted to a second end plate on the X-beams. The unusual cross-beam structure and the unusual rigid leg structure and rigid interconnection provide rigidity of the entire crane. The vertical support legs accommodate variations in tracks.
A new gantry crane has a rigid open three-dimensional horizontal beam having first and second ends. A rigid open three-dimensional leg structure is rigidly connected at the first end of the rigid open three-dimensional beam. A vertically supporting second leg structure is connected to the second end of the rigid open three-dimensional beam.
Flexible connectors are connected between the tops of the vertically supporting leg structure and the second end of the beam. A transverse end plate is connected at the top of the second end of the beam, and vertical plates are connected between the end plate and tops of the second leg structure. The second leg structure has first and second inward sloping tubes having upper ends connected to vertical plates in vertical planes and having lower ends connected to horizontal plates.
Carriage housings have axles extending horizontally through the housings and wheels mounted on the axles. Horizontal plates at the bottoms of the legs are connected to the carriage housings.
The rigid leg structure has first and second upward and inward converging vertical legs and vertical connection plates at the tops of the first and second legs for connection to a cross-beam end plate at the top of the open three-dimensional horizontal beam. A lower member of the horizontal beam has an extended first end which extends outward between the first and second legs. Third and fourth upward extending, inward converging and outwardly sloping legs form a torque-resistant triangular box. A top plate is connected to tops of the third and fourth outwardly sloping legs. A complementary sloping end plate is connected to an extended end of the lower beam member. The sloping end plate is bolted to the top plate at the tops of the third and fourth legs. A carriage is connected to bottoms of the first, second, third and fourth legs, axles connected to the carriage near ends of the carriage, and wheels connected to the axles. First and second horizontal plates are connected respectively at bottoms of the first and third legs and at bottoms of the second and fourth legs. The horizontal plates are connected to the carriage.
Preferably the first, second, third and fourth legs are tubular legs. An inverted triangular rigidifying support is connected between the first and second legs. The inverted triangular support has a downward pointing apex connected centrally to the carriage and vertical divergent support legs extending upwardly and outwardly from the apex to mid points of the legs. A cross-member base extends between the two middle portions of the first and second legs at the upper ends of the rigidifying support legs, completing the welded triangular reinforcement. Preferably the triangular reinforcement support legs and the base are tubular members.
First, second and third medial support tubes respectively extend between the first and third, the third and the fourth and fourth and second legs at positions near the cross member base to provide further strengthening and rigidifying support.
An end plate is connected at one end of the open three-dimensional beam. Angular support plates extend outward, downward and inward from ends of the end plate on the beam. Gussets extend downward and inward from the angular support plates to the sloping plate fixed on the extended first end of the lower member.
The open three-dimensional beam has a longitudinally extending lower member having a vertical web and oppositely extending lower horizontal flanges for supporting a movable crane trolley. First and second spaced longitudinally extending upper members are parallel to the lower member. Upper cross-members extend between the first and second upper members, and angular gussets extend between the lower member and the first and second upper members. Preferably the upper members are X-beams, and the upper cross-members extending between the upper members are angle irons. Each upper member X-beam is formed from two angle irons mounted as X-shapes. The angle irons are connected at intervals alternately by downward and inward sloping plates and by upward and inward sloping plates.
Each downward and inward extending plate is connected to two different pairs of gussets extending at angles to each other.
In preferred embodiments, each gusset pair has two parallel members. Upper end portions are connected to the downward and inward extending plates. Upward and outward extending lower plates are welded to the lower I-beam member. Lower ends of the gussets are connected to the upward and outward extending lower plates. Each upward and outward extending lower plate and each downward and inward extending upper plate is connected to two different gussets extending in different directions. Gussets at the ends of the three-dimensional beam extend upward and diagonally outward and are connected to ends of the upper members and to the end plates.
Each gusset has spaced parallel elements which are connected at lower and upper ends respectively to the upward and outward extending plates and to the downward and inward extending plates. The gussets have spacers connected between the two parallel elements at intervals along the gussets. The upper cross-members extend angularly between the longitudinal upper members.
A trolley has wheels mounted on outward extending flanges of the lower member. A drive motor is operatively connected to at least one of the wheels for moving the trolley back and forth along the lower member. Pulleys are mounted on the trolley. A winding motor is mounted on the trolley and is connected to a reel. A cable is connected to the reel and is connected to the pulleys and to a movable sheath supported by multiple strands of the cable. A hook is supported by the movable sheath for lifting and lowering loads.
Carriages are mounted on the lower ends of the leg structures at first and second opposite ends of the crane. Axles are mounted on the carriages, and roller wheels are mounted on the axles. Synchronous, stepping or frequency drive motors are connected to wheels on the carriages for moving the carriages back and forth along rails. If one or more motors fail, a single motor and drive wheel can drive both carriages.
These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings.
The gantry crane of the invention is generally indicated by the numeral 1. The gantry crane has an upper open truss three-dimensional cross-beam generally referred to by the numeral 3. The beam 3 is supported rigidly at a first end 5 by a rigid leg structure 7. A second end 6 of beam 3 is supported by vertical support legs 9. Carriages 11 and 13 are connected to the bottoms of rigid support legs 7 and to the bottoms of vertical support legs 9, respectively. The carriages have axles 15 and wheels 17, at least some of which are driven, preferably by synchronous motors, frequency motors or stepping motors to assure that the carriages move together when on tracks. Because of the unique construction, if one motor fails, the remaining motor or motors may move the crane successfully.
The three-dimensional open beam 3 has a lower member 21, which is preferably an I-beam with a vertical web 23 and lower oppositely extending flanges 25, on which wheels 27 of a trolley 29 ride. Beam 3 has two upper members 31, which are constructed as X-beams and which are provided at opposite ends with cross-member end plates 33 and 35, respectively.
A first end 37 of the I-beam lower member 21 extends axially outward beyond the upper members 31, which are connected to end plate 33. A second end 39 of the lower member 21 is spaced slightly inward from the second ends of the upper members 31, which are connected to the end plate 35. Gussets 41 connect the upper and lower members. Preferably each gusset has first and second parallel elements 43 and 45, which are connected between downward and inward extending plates 47 on the upper members 31, and upward and outward extending plates 49 on opposite sides of the lower member 21.
At the rigidly fixed end 5, as shown in
As shown in
A rigidifying outrigger structure 70 has legs 71 and 73 which extend inward and upward from lower plates 57, which are mounted on top of carriage 11 to a mounting plate 77, which is bolted to plate 38. Gussets 75, which are similar to gussets 41, extend from the upper end plate 33 downward and inward to the mounting plates extending inward from end plate 38. The lower ends of gussets 75 are welded to the inward extending mounting plates. The upper ends of legs 71 and 73 are grooved and welded to the mounting plate 77. Mounting plate 77 is secured by bolting it onto the mounting plate 38 at the extended end 37 of the lower beam 21.
The vertical support legs 9, as shown in
As shown in
In
As shown in
Gear 159 is connected 158 to one wheel on each trolley or both wheels on both trolleys. The gear is driven by direct coupled synchronous, stepper or frequency motors and speed reducers.
In
The gantry crane may be shipped to the job site in major preassembled pieces erected at the job site and secured by bolting the sections together at five locations after the trolley is mounted on the lower beam 21 and stops 161 and 163 are mounted at opposite ends of the lower beam.
The rigidity of the leg structure 7, the rigidity of the main beam 3 and the rigidity of their interconnections at the end 5 provide stability and rigidity of the entire gantry crane. The vertical plate connections at the top of the vertical support leg structure 9 at end 6 of the beam 3 accommodates slight variations in track conditions. In preferred embodiments, the vertical support leg structure 9 is constructed of 8″ steel tubes. The rigid leg support structure 7 is constructed of 6″ steel tubes.
While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention, which is defined in the following claims.
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