JP2010531286A - Rubber tire gantry crane with land power - Google Patents

Abstract

  An apparatus for connecting electrical power from a land vehicle to a rubber tire gantry (RTG) crane includes a power relay trolley and, optionally, an RTG crane. The power relay trolley receives power via a high voltage cable or via inductive power coupling and outputs a low AC voltage or a low DC voltage via a flexible power cable for connection to an RTG crane. In order to reduce the control accuracy requirements for the RTG crane, the guidance device guides the power relay trolley along the chosen path. The RTG crane can move from one chosen route to another chosen route without interrupting the high voltage connection. The power relay trolley optionally determines the position of the power relay trolley relative to the chosen path, which in some embodiments has a guide rail and in other embodiments has a guide wire. Embodiments of the power relay trolley are self propelled or pulled by an RTG crane.

Description

  The present invention relates generally to an apparatus for supplying power to a gantry crane.

  Gantry cranes are adapted to lift and move large and heavy loads, such as cargo containers. The gantry crane includes a hoist mounted on a hoist reciprocating rack that can move laterally along one or more girders. Two or more vertical supports, each attached at the upper end to the end of the spar, hold the spar above the ground. There are also gantry cranes that have wheels and motors coupled to a structural member attached to the lower end of the vertical support, allowing the gantry crane to travel by itself from where the load is picked up to another location where the load is unloaded.

  Mobile gantry cranes, such as those used in cargo yards, generally have a pair of parallel beams for supporting hoists and hoist carriages, at least four supports, and wheels near each of the lower corners of the crane. There are gantry cranes known as rail-running gantry cranes (RMG cranes) with flanged metal wheels adapted to roll on track rails fixed to the ground, similar to the wheels and rails used in trains. Rails allow the RMG crane to move quickly and accurately, but the cost of laying or moving the rails is high. Another type of gantry crane, known as a rubber tire gantry crane (RTG crane), has rubber tires instead of metal wheels and is not constrained by fixed rails during operation. Instead, the wheels of the RTG crane move on a prepared road surface known as the runway. A pair of parallel tracks constitutes a lane along which the RTG crane moves. The wheels of the RTG crane may be steerable to change the direction of travel of the RTG crane, for example to move from one lane to another. RTG cranes may be preferred over RMG cranes when logistics flexibility is desired.

  Some RTG cranes are powered by an on-board diesel engine coupled to a generator. The electrical output from the generator supplies power to an electric motor for moving the RTG crane and for operating hoists and other equipment. However, emissions from diesel engines are becoming a major problem at some ports and cargo terminals. An alternative is to operate the RTG crane with power supplied from the transmission and distribution network in the cargo accumulation area. A transmission / distribution network may be referred to as land power if the network is near a cargo ship loading / unloading work area.

  An example of an RTG crane operated by land power is shown in FIG. An RTG crane 100, which represents an RTG crane known in the art, includes a hoist 102 and rubber tires 104. The RTG crane 100 moving along the runway 112 is depicted. Two parallel running paths 112 constitute an RTG lane. The runway 112 can include a reinforced concrete pavement that is strong enough to bear the weight of a heavy duty RTG crane. The RTG crane 100 straddles the load, lifts the load, and carries the load along the RTG lane. In the example of FIG. 1, one of the stacked cargo containers 114 is an example of a load that is lifted and carried by the RTG crane 100. One of the cargo containers of FIG. 1 is approximately 8 feet (2.4 meters) wide, approximately 8 feet 6 inches (2.6 meters) high, and approximately 20 feet (6.1 meters) long, The weight can be over 20 US tons (approximately 18000 kilograms). Cargo containers having other dimensions and weights are also moved by the RTG crane. Some RTG cranes can lift loads much larger than a single cargo container.

  A significant amount of power can be required to operate an RTG crane. The RTG crane 100 of FIG. 1 receives power via a cable connected to land power. For reasons of transmission efficiency, power can be transmitted over the cable at high voltage and relatively low current. Power transmission at a relatively low current enables the use of cables that are smaller in diameter and more flexible than cables that carry large currents. For example, there are RTG cranes where the input power is AC (alternating current) with a voltage in the range of about 2000 volts AC (VAC) to about 6000 VAC. To avoid cable damage and to prevent humans and equipment from touching high voltages, the RTG crane input power transmission cable can be placed in a groove near the runway. Fences or other barriers may be provided to further protect people, cables and other equipment.

  As the RTG crane 100 of FIG. 1 travels along the RTG lane, the high voltage cable is wound on and unwound from the cable reel on the crane. In FIG. 1, the crane-mounted cable reel 106 is attached to the side surface of the RTG crane 100. As the RTG crane 100 moves along the RTG lane, the high voltage cable 108 is pulled up from the cable groove 110 and wound on the crane-mounted cable reel 106. When the RTG crane 100 moves in the opposite direction along the lane, the high voltage cable 108 is unwound from the crane-mounted cable reel 106 and returned to the cable groove 110 for storage. A rotary power coupler at the hub of the crane-mounted cable reel 106 connects the high voltage from the high voltage cable 108 to the input side of the high voltage transformer 116. The output of the high voltage transformer 116 is a relatively low AC voltage, for example, an AC voltage in the range of about 400 VAC to about 500 VAC. The transformer output voltage is connected to an electrical input on the RTG crane to operate the electric motor and other equipment.

  Some cargo terminals have more than one RTG lane to allow RTG crane access to multiple loading / unloading locations. An example of a terminal area with more than one RTG lane is shown in FIG. In FIG. 2, the RTG crane 100 which moves along the 1st RTG lane which consists of the two runways 112-1 performs work in the 1st loading place A and the 2nd loading place B. In FIG. A second pair of runways 112-2 forming an intersecting lane provides the RTG crane 100 with access to a third loading location C to which a third RTG lane consisting of two runways 112-3 approaches. . When the RTG crane 100 is traveling between the locations A and B, the high voltage cable connected to the RTG crane is held in the first cable groove 110-1. When the RTG crane 100 is moving along the RTG lane sandwiching the loading place C, the high voltage cable connected to the RTG crane is held in the second cable groove 110-2.

  In order to move the cargo from the loading place A to the loading place C in the example of FIG. 2, the RTG crane 100 performs cross lane maneuvers by moving on the runway 112-1 from the place A to a position near the crossing runway 112-2. The high voltage cable from the first cable groove 110-1 is disconnected from the RTG crane 100, and a mobile high voltage power source 118, eg, a truck mounted generator, is connected to the RTG crane 100 with a cable. The RTG crane 100 changes direction, crosses the lane, and moves close to the RTG lane consisting of the runway 112-3 to the loading place C. The RTG crane 100 is guided onto the RTG lane to the loading location C, the mobile high voltage source 118 is disconnected from the RTG crane, and the high voltage cable in the second cable groove 110-2 is attached to the RTG crane. Finally, the RTG crane 100 proceeds to loading location C where the cargo is unloaded.

  In the cross lane maneuver described above, the RTG crane 100 moves from land power to a mobile generator and then back to land power while changing lanes, so two high voltage disconnecting operations and two high voltage connecting operations are performed. There is. Some cargo terminals can only be connected and disconnected by high-voltage cables due to safety hazards associated with high voltages. If there are no trained workers at the time and place where cross-lane maneuvers should take place, cargo work delays can occur. Cargo operations can be further delayed by the time required to connect and disconnect high voltages.

  The RTG crane 100 is guided such that the high voltage cable 108 is pulled out of the cable groove 110 and stored in the cable groove 110 with minimal stress and wear on the high voltage cable 108 and crane mounted cable reel 106. Is preferred. More preferably, the high voltage cable 108 is placed flat and straight on the bottom of the cable groove 110. For example, a high voltage supply system that requires the RTG crane 100 not to deviate more than about ± 0.4 inches (± 10 cm) from the selected lane in order to achieve the selected high voltage cable arrangement. is there. However, an RTG crane 100 with a common type of maneuvering system will stagger about 6 inches (150 mm) on either side of the selected lane as the RTG crane 100 travels along the track. It is also well known that some pilots have guidance accuracy of about ± 10 inches (254 mm) achieved while maneuvering a diesel power RTG crane.

  In the above example, the sum of the position error due to the steering system of the RTG crane 100 and the position error due to the operator's ability may exceed the position accuracy specification for the cable placement. Thus, the precise positioning of the RTG crane 100 with respect to the cable groove 110 may require a special and expensive position measurement / control device. A position measurement / control device for accurately guiding the RTG crane 100 along a chosen path is known as a straight-steering system. Even for an RTG crane 100 equipped with an accurate straight maneuvering device, the speed at which position measurements are made is limited, and the RTG crane 100 is operated at a speed slower than preferred for economic cargo operations. Otherwise, the speed and accuracy with which the position error is corrected may not be obtained.

  What is needed is a means of connecting electrical power to an RTG crane without connecting / disconnecting high voltage cables during daily cargo transfer operations. There is also a need for a means for accurately guiding the RTG crane to achieve a selected high voltage cable arrangement without the need for an RTG crane linear steering system.

  In one embodiment, the RTG crane is electrically connected to the RTG crane and is adapted to operate at a relatively low voltage supplied by a trolley, which is a relatively small transport vehicle that moves in close proximity to the RTG crane. Is done. A trolley for supplying power to an RTG crane is also referred to herein as a power relay trolley. In some embodiments, the power relay trolley includes one or more drive motors for propulsion and, if necessary, direction control. In another embodiment, the power relay trolley is pulled by an RTG crane.

  A high voltage cable connects power from an external alternating current (AC) high voltage power source, such as a land power source, to the input side of a step-down transformer mounted on a power relay trolley. The output of the step-down transformer is a relatively low AC voltage. The relatively low transformer output AC voltage is routed through the flexible power cable to the input electrical contacts on the RTG crane, where the relatively low AC voltage is applied to the rectifier, inverter, motor controller, motor and other equipment on the RTG crane vehicle. Power distribution. In some embodiments, a power conversion circuit on the power relay trolley converts alternating current power into direct current (DC) power. The DC voltage / current from the power conversion circuit is connected to the flexible power cable and then to the RTG crane.

  The input side of the high voltage transformer on the power relay trolley usually remains connected to land power. Thus, an RTG crane equipped with a power relay trolley can complete many maneuvers without interrupting the high voltage connection. For example, for a facility provided with a plurality of RTG lanes, a power relay trolley can be individually provided in each RTG lane as necessary. During cross lane maneuvering, a flexible low voltage cable carrying a relatively low voltage from the first power relay trolley on the RTG lane is disconnected from the RTG crane and second after the RTG crane enters the second RTG lane. A flexible low voltage cable from each power relay trolley is connected to the RTG crane and the high voltage connection to each power relay trolley is not interrupted. The power for the cross lane portion of the cross lane maneuver can be supplied by a relatively low voltage portable power source. Other RTG crane maneuvers required to separate the RTG crane from the power relay trolley also require relatively low voltage disconnection and reconnection.

  In some embodiments, the power relay trolley includes a cable reel for holding a portion of the high voltage cable. The high voltage cable is wound on a cable reel as the RTG crane and power relay trolley move together in one direction along the track. The high voltage cable is unwound from the reel and returned to the cable channel or other protective structure as the RTG crane and power relay trolley move together along the runway in the opposite direction. In another embodiment, the high voltage cables and cable reels are omitted, and the high voltage AC power is a contactless power located at the bottom or side of the high voltage rail system and power relay trolley located in the ground groove. The pickup is connected to the input side of the transformer on the power relay trolley.

  Position control for an RTG crane connected to the power relay trolley by maintaining an uninterruptible high voltage connection to the power relay trolley and precisely controlling the position of the power relay trolley relative to the cable groove or other high voltage cable protection structure The tolerance can be relaxed compared to the control tolerance of RTG cranes known in the art. Therefore, it is possible to simplify the RTG crane vehicle position measurement / control device and reduce the cost. Furthermore, since the power relay trolley is smaller and lighter than the RTG crane, the position of the power relay trolley is more easily controlled than the position of the RTG crane.

  In some embodiments, the position of the power relay trolley relative to the cable groove is accurately maintained by following the power relay trolley on a guide rail attached to the pavement near the groove. A pair of guide roller assemblies mounted on both sides of the power relay trolley follow the guide rail to control the separation distance between the power relay trolley and the cable groove. In some embodiments, the power relay trolley straddles the guide rail. Alternatively, the guide roller assembly extends from the side of the power relay trolley and the power center trolley travels on a path adjacent to the guide rail. In some embodiments, the high voltage cable is housed in a channel formed in the guide rail instead of a groove. In some power relay trolley embodiments with an on-board drive motor and a position controller, the position controller automatically causes the power relay trolley to follow an induction wire laid in a pavement groove. The position controller reads the position deviation signal from a magnetic sensor or an induction sensor attached to the power relay trolley to determine the position of the power relay trolley with respect to the induction wire and the corresponding position of the power relay trolley with respect to the cable groove. In another embodiment, a sensor on the power relay trolley detects a relative separation distance between the power relay trolley and the guide rail, and a position controller on the power relay trolley controls a drive motor on the power relay trolley to Maintain the distance at the chosen value.

  Some RTG cranes have a diesel engine and an AC generator driven by the diesel engine. The AC output of the generator is converted to a DC voltage. The DC voltage from the power relay trolley or from the engine, generator and rectifier on the RTG crane is distributed to other equipment on the RTG crane. The DC voltage can be converted back to an AC voltage by an inverter on the RTG crane, for example to supply power to the induction motor. The power relay trolley with DC power output is advantageous in that it can be later installed on an RTG crane with a diesel engine and an AC generator so that the RTG crane can be operated by land power without the need for an accurate straight-ahead maneuvering system. is there.

  Optionally, a wheel position encoder, eg a rotary encoder, is mounted between the drive motor and the wheel on some power relay trolley embodiments and on some RTG crane embodiments. A position controller on the power relay rotary reads the output of the wheel position encoder and calculates the position of the power relay trolley relative to an external reference point. A position controller on the RTG crane calculates the corresponding RTG crane position. The position controller on the power relay rotary and the position controller on the RTG crane can exchange position information as needed. For example, in some embodiments, the position of the power relay trolley is known with higher accuracy than the position of the RTG crane due to the position reference provided by the guide rail. The position reference given to the RTG crane by the power relay rotary can serve as a control input to the position calculator on the RTG crane, thus simplifying the RTG crane control system and correspondingly reducing the cost of the RTG crane control system , Can increase the operating speed.

  Embodiments of the power relay trolley with an on-vehicle drive motor can have rubber tires if desired. Some embodiments with rubber tires follow a guide rail or guide wire as described above. Another embodiment with a rubber tire measures the separation between the power relay trolley and the external structure as previously described. Other embodiments have flanged metal wheels and the power relay trolley is pulled by the RTG crane along a metal track rail attached to the pavement or pavement groove. The track rail is arranged in parallel with the runway. Or a runway can be pinched | interposed with a pair of track rail as needed.

  This section summarizes some features of embodiments of the present invention. The above and other features, aspects and advantages of embodiments of the present invention will be better understood with regard to the following description and with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an RTG crane that is powered by a high voltage cable connected to a rubber tire gantry (RTG) crane. FIG. 1 represents an RTG crane known in the art. FIG. 2 is an overhead view of cross lane maneuvers to be performed by the RTG crane of FIG. FIG. 3 is a schematic diagram of an RTG crane according to the present invention. The RTG crane of FIG. 3 is adapted to receive relatively low voltage power from a power relay trolley connected to a high voltage cable. FIG. 4 is a side view of one embodiment of a power relay trolley and one embodiment of a guide rail on a pavement. FIG. 5 is an end view of the power relay trolley of FIG. 4, a pull rod for mechanically coupling the power relay trolley to the RTG crane and a flexible power cable for electrically connecting the power relay trolley to the RTG crane. Is further shown. FIG. 6 is another embodiment of the lower part of the power relay trolley. The line-of-sight direction of this partial cross-sectional view is indicated by line AA in FIG. FIG. 6 shows an embodiment of a power relay trolley having a guide device with a guide roller assembly coupled to the side of the power relay trolley. The illustrated embodiment shows a guide rail near the side of the power relay trolley and a high voltage cable placed in a channel in a groove formed in the guide rail. FIG. 7 is another embodiment of the lower part of the power relay trolley. The line-of-sight direction of this partial cross-sectional view is indicated by line AA in FIG. FIG. 7 shows an embodiment of a power relay trolley that straddles a cable groove formed in a pavement. The high voltage cable is placed in the cable groove. FIG. 8 is another embodiment of the lower part of the power relay trolley. The line-of-sight direction of this partial cross-sectional view is indicated by line AA in FIG. FIG. 8 shows a power relay trolley having flanged metal wheels that run on metal track rails laid on a pavement. The high voltage cable is shown in a groove adjacent to one of the track rails. Track rails are shown on both sides of the track. FIG. 9 is another embodiment of the lower part of the power relay trolley. The line-of-sight direction of this partial cross-sectional view is indicated by line AA in FIG. FIG. 9 shows a power relay trolley adapted to receive high voltage input power from two high voltage conductors attached to rails laid in a pavement groove. A non-contact power coupler for receiving power from a high voltage conductor attached to a frame member of a power relay trolley is shown. FIG. 10 is a simplified block diagram of a power relay trolley having a rubber tire driven by an electric motor. The selected separation distance between the power relay trolley and the guide rail is shown in the figure. FIG. 11 is a simplified block diagram of a power relay trolley having an accompanying sensor interface that communicates with two position sensors and a position controller. The figure shows a first separation distance between the first sensor and the elongated guide rail and a second separation distance between the second sensor and the rail. The chosen travel direction parallel to the guide rail is also shown. FIG. 12 shows the deflection angle between the selected travel direction and the actual travel direction for the power relay trolley of FIG. FIG. 13 shows a power relay having a motor for self-propulsion and an induction device for automatically following an induction signal placed on the induction wire in the induction wire groove so that the high voltage cable can be accurately placed in the cable groove. 1 is a schematic illustration of an embodiment of a trolley. FIG. 14 is a block diagram of an on-vehicle power distribution device and position control device of any RTG crane known in the art. FIG. 15 illustrates an embodiment of an RTG crane adapted in accordance with the present invention to receive DC input power from a power relay trolley and power relay trolley adapted to provide DC output power. FIG. 16 is a block diagram of an RTG crane adapted in accordance with the present invention to operate with input power having a relatively low input voltage. Position signal contacts and crane position control means provided as required are also shown. FIG. 17 is a block diagram of a power relay trolley adapted to output power having a relatively low DC voltage and an RTG crane adapted to receive DC power from the trolley. An RTG crane on-board diesel engine and ancillary power generation / conversion device are also provided as needed.

  Embodiments of the present invention provide power to a rubber tire gantry (RTG) crane from land power at a relatively low voltage, thus disconnecting from the power source of the RTG crane and another power source without interrupting the high voltage cable connection. Includes a device that allows reconnection to. Some embodiments accurately route the high voltage cable at the selected location as the embodiment travels on the selected route. Another embodiment receives energy from a high voltage conductor by inductive coupling, precisely according to a stationary high voltage conductor, such as a high voltage cable or high voltage rail. Another embodiment couples electrical energy from the rail to the RTG crane, precisely following the rail through which the high voltage current is flowing. Some embodiments of the present invention are well suited for use with new RTG cranes, while other embodiments are well suited for retrofitting existing RTG cranes. Some embodiments include an RTG crane adapted for operation with a power source having a relatively low voltage.

  The height of the voltage that is considered high voltage can vary from place to place according to local requirements such as safety rules, labor practices, etc. Therefore, high voltage is used herein to mean a voltage equal to or higher than the threshold voltage that must be disconnected and disconnected by a professionally trained worker. Such a voltage below the threshold voltage is referred to herein as a low voltage or a relatively low voltage.

  One embodiment of an RTG crane adapted for low voltage operation is shown in FIG. In the embodiment of FIG. 3, the power relay trolley 200 is mechanically coupled and electrically connected to an RTG crane 300 adapted for operation with a low voltage power source in accordance with the present invention. The power relay trolley 200 is mounted on the left or right side of the RTG crane 300 according to the requirements of a specific cargo terminal as required. In another embodiment, the power relay trolley 200 can be placed in front of or behind the RTG crane 300 as required.

  In the embodiment of FIG. 3, the power relay trolley 200 is pulled by the RTG crane 300 along the guide rail 202. A pull bar 206 having a hinged connection to the power relay trolley 200 fits into a pull bar receiver 208 attached to a structural member on the RTG crane 300. A slip fit between the pull bar 206 and the pull bar receiver 208 allows the separation between the power relay trolley 200 and the RTG crane 300 to vary over a selected range. For example, in some embodiments, the separation can vary from a reference position to about 10 inches (about 25 cm).

  Power connection to the RTG crane 300 is made via the power relay trolley 200. A high voltage cable sends power to the power relay trolley 200 from an external power source. Some of the high voltage cable fits in the cable groove 110 and some of the high voltage cable is collected on the cable reel 204 attached to the power relay trolley 200. A rotating electrical contact on the hub of the cable reel connects the high voltage power to the distribution line on the power relay trolley and then to the input side of the high voltage transformer mounted on the power relay trolley. The low voltage output from the high voltage transformer is connected to the flexible power cable 210, which is connected to the power input terminal on the RTG crane 300.

  Referring to FIG. 1, note that the high voltage transformer 116 and the crane mounted cable reel 106 are placed on the RTG crane 100. This configuration is well known in the art and, as discussed above, requires that the RTG crane accurately follow the path of the cable groove to place the high voltage cable 108 at a selected position at the bottom of the groove. For example, to perform cross lane maneuvers, the high voltage connection to the RTG crane 100 of FIG. 1 must be interrupted in order to move the RTG crane 100 of FIG. In contrast, the power relay trolley 200 of FIG. 3 remains connected to the high voltage cable through normal cargo transfer operations, including cross-lane maneuvers and other RTG crane operations, and the RTG crane 300 according to the present invention is powered. Disconnected from the relay trolley. When the RTG crane 300 of FIG. 3 is disconnected from the power relay trolley 200, the low voltage output from the power relay trolley 200 via the flexible power cable 210 is interrupted. Thus, power connection to the RTG crane 300 connected to the various embodiments of the present invention can be made without using an operator who has received specialized training in high voltage work. In addition, by accurately following the selected path defined by the guide rail 202, the power relay trolley 200 accurately places the high voltage cable at the selected location, while the RTG crane 300 has a significant allowable position error. And travel freely along the track. Therefore, the RTG crane 300 that receives power from the power relay trolley 200 does not require a high-precision straight-ahead steering system for maintaining a connection to the power source.

  The power relay trolley 200 according to the embodiment of FIG. 3 is shown in more detail in FIGS. 4 (side view) and 5 (end view). A trolley wheel 226 connected to the power relay trolley 200 in a rotatable manner is placed on the surface of the pavement 228. In the embodiment of FIGS. 4 and 5, the power relay trolley 200 has at least one frame member 218 and at least one structural support 216 coupled to the frame member 218. A high voltage transformer 214 is attached to the frame member 218 and the cable reel 204 is coupled to the structural support 216 in a rotatable manner. The high voltage cable 108 connects the high voltage land power to the on-vehicle high voltage transfer cable 424 of the power relay trolley 200 via the rotating high voltage coupler on the cable reel 204. The high voltage on transfer cable 424 is connected to the input of high voltage transformer 214. The high voltage transformer 214 is a step-down transformer, and its output is a low voltage. The low voltage output from high voltage transformer 214 is connected to flexible power cable 210. The flexible voltage cable 210 is adapted for connection to a low voltage power input contact on the RTG crane.

  The power relay trolley 200 of FIGS. 4 and 5 achieves selected position accuracy by following the guide rail 202. The guide rail 202 is firmly attached to the pavement 228. Variation in linearity of the vertical side surface of the guide rail 202 contributes to an error factor to the position accuracy of the power relay trolley 200. A guide device maintains a selected separation between the guide rail 202 and a portion of the power relay trolley 200. 4 and 5, the guidance device includes a first power relay trolley induction roller assembly 224-1 attached to the front end of the power relay trolley 200 and a second power attached to the rear end of the power relay trolley 200. It has a power relay trolley induction roller assembly 224-2. The guide roller assembly 224 has at least two guide rollers 220, each guide roller being rotatably coupled to the guide roller assembly. The first guide roller 220 contacts the first vertical side surface of the guide rail 202, and the second guide roller 220 contacts the second vertical side surface of the guide rail 202. The guide roller 220 causes the power relay trolley 200 to closely follow the path defined by the guide rail 202. In some embodiments, the power induction trolley straddles the induction rail, and in other embodiments, the power relay trolley runs beside the induction rail. In the illustrated embodiment, the guide roller 220 and guide rail 202 are made of metal, such as steel. The guide rail embodiment preferably has sufficient strength to limit the bend to an amount significantly less than the desired position tolerance of the power relay trolley.

  In some of the embodiments described above, the high voltage cable fits in the cable channel to protect the cable from damage and to protect people and equipment from high voltages. FIG. 5 shows another option for the location of the high voltage cable. In FIG. 5, a part of the high voltage cable 108 is wound around the cable reel 204 as described above. The high voltage cable 108 passes through the opening of the power relay trolley 200 and enters the space below the power relay trolley where a portion of the cable fits into a channel formed on the top surface of the guide rail 202. In FIG. 5, the cross section of the high voltage cable 108 and the cross section of the guide rail 202 can be seen between a pair of guide rollers.

  6, 7, 8 and 9 show different embodiments of the lower part of the power relay trolley, as seen in the direction indicated by the partial section line marked by line AA in FIG. The elements above the partition line AA in FIG. 4 can be considered to be compatible with all of the embodiments shown in FIGS. In the embodiment of FIG. 6, the high voltage cable passes by the power relay trolley instead of being spanned by the power relay trolley. Two wheels 226 and a frame member 218 indicate the position of the main part of the power relay trolley relative to the guide rail 202. The guide rail 202 is formed including a channel in which the high voltage cable 108 is accommodated (or the cable is pulled out) when the power relay trolley travels. The guide roller assembly 224 is connected to the frame member 218 at the side of the power relay trolley, and the guide roller 220 traces the side of the guide rail as described above.

  In the embodiment of FIG. 7, a portion of the high voltage cable is laid in a cable groove 110 formed in the pavement 228. The power relay trolley straddles the cable groove 110. The separation distance between the cable groove 110 and the guide rail is selected such that the high voltage cable 108 is laid in the groove as the power relay trolley moves along the guide rail. At least two induction roller assemblies 224 cause the power relay trolley to accurately follow the path defined by the induction rail 202. The embodiment of FIG. 6 can also be adapted to place a high voltage cable in the groove, as in FIG.

  In some embodiments, the power relay trolley runs on a pair of parallel metal rails similar to a train track. In the embodiment shown in FIG. 8, a pair of track rails 232 are disposed in grooves formed in the pavement 228. The track rails 232 are on both sides of the runway 112. Alternatively, both track rails 232 can be placed on the same side of the runway 112, as shown in FIG. A flanged wheel 230 adapted to roll on the track rail 232 is coupled to the frame member 218 in a rotatable manner. In the embodiment of FIG. 8, the power relay trolley is pulled behind (or pushed forward) the RTG crane. One of the pavement grooves of FIG. 8 holds the track rail 232 and further serves as a cable groove in which the high voltage cable 108 is housed. The high voltage cable 108 can be housed in an independent groove as required. The embodiment of FIGS. 6 and 7 can also be adapted to sandwich the runway, as in FIG. Power relay trolleys with flanged wheels that roll on track rails can also be adapted to high voltage cable arrangements, as in FIGS. 6 and 7, with guide rails as needed.

  The high voltage can be connected to the power relay trolley by means other than the high voltage cable. In FIG. 9, two high voltage conductors 902 are arranged in a groove formed in the pavement 228. The high voltage conductor 902 is connected to a high voltage AC power source having voltage, current and frequency chosen for efficiency of inductive coupling to the power relay trolley and for powering the RTG crane. A contactless power coupler 900 attached to a frame member 218 on the power relay trolley moves alongside the high voltage conductor 902 along the high voltage conductor 902 as the power relay trolley moves along the track rail 232. . Power is inductively coupled from the high voltage conductor 902 to the power coupler 900 and connected from the power coupler 900 to the input of the high voltage transformer on the power relay trolley. A power relay trolley equipped with an inductive power coupler does not require a long high voltage cable to connect to a cable reel or an external high voltage power source. However, the contactless power coupler 900 must follow the proximity of the conductor without contacting the high voltage conductor 902, and thus in this embodiment, a flange on the track rail 232 to provide accurate position control. Attached wheels are used.

  Towing power relay trolleys as large RTG cranes move along the RTG lane carrying cargo is well within the capacity of such RTG cranes. In some embodiments, the RTG crane pushes or pulls the power relay trolley in front of or behind the RTG crane using conventional traction tools. In another embodiment, the power relay trolley is advanced beside the RTG crane as shown in FIG. The pull rod arrangement for towing the power relay trolley beside the RTG crane is shown in the end view of the power relay trolley in FIG. A pull bar 206 having a hinge attachment to a portion of the power relay trolley 200 and supported by a hinge linkage attached to another portion of the power relay trolley is shown in FIG. The pull rod 206 in the illustrated embodiment can be rotated to a vertical position so that it does not interfere with other equipment or prevent a person from hitting the pull rod when the power relay trolley is not in use. be able to. The pull bar receiver on the RTG crane is adapted to apply force to the pull bar 206 to move the power relay trolley forward or backward in response to movement of the RTG crane. The pull bar receiver on the RTG crane is also adapted to allow a change in the separation distance between the power relay trolley and the RTG crane. The separation distance varies to some extent as a result of the difference in guidance accuracy between the power relay trolley and the RTG crane.

  In some embodiments, the power relay trolley is not towed by an RTG crane, but instead one or more power relay trolley wheels for propelling the power relay trolley forward or backward along a selected path. Equipped with a drive motor coupled to. A simplified block diagram of a power relay trolley with a drive motor is shown in FIG. The embodiment of FIG. 10 includes a power relay trolley 200 having four rubber tires 408, at least one of which is coupled to an electric drive motor 406. The position controller 404 exchanges signals with the drive motor 406 to control the traveling direction and traveling speed of the power relay trolley 200. The position controller 404 may be, for example, a programmable logic controller, a microprocessor, a microcomputer, a microcontroller, or any other preferred hardware for automatically controlling the value of a selected parameter within a selected limit range. And software can be included as needed. In some embodiments, the power relay trolley has more than one drive motor 406 under the control of the position controller 404 so that the position controller 404 can change the direction of travel of the power relay trolley 200. . Alternatively, the position controller 404 exchanges control signals with steering actuators coupled to one or more drive wheels to change the direction of travel.

  In FIG. 10, a cable reel 204 that is rotatably attached to the power relay trolley 200 holds a portion of the high voltage cable 108. Another portion of the high voltage cable 108 fits within a channel formed in the guide rail 410. A high voltage transfer cable 424 connects the high voltage from the cable reel 204 to the high voltage input of the high voltage transformer 116. The output of the high voltage transformer 116 is a low voltage on the flexible power cable 210. The flexible power cable 210 is connected to a power input terminal on the RTG crane.

  The guide rail 410 shown in FIG. 10 has an extended height compared to the guide rail 202 of FIG. The stretch guide rail 410 can provide even higher protection and isolation of the high voltage cable 108 compared to the guide rail 202 of FIG. The sides of the stretch guide rail 410 can also be used as a position reference for one or more position sensors. As shown in FIG. 10, the position sensor 400 measures a separation distance “L” between the sensor 400 and the extension guide rail 410. The position sensor can be, for example, an acoustic distance measurement sensor, an optical distance measurement sensor, a Hall effect sensor, a pressure sensor with a probe for contact measurement, or other types of sensors. The sensor output signal is connected to a sensor interface module 402 having an output connected to the input of the position controller 404. The output signal from the sensor interface module 402 may be, for example, a position error signal that is proportional to the deviation from the selected distance “L” value. Alternatively, the output signal can be a value representing the distance “L”. The position controller 404 determines the value of the output signal of the sensor interface module 402 and, depending on that value, issues a control signal to one or more drive motors 406 or to the steering actuator to power relay trolley 200. The traveling direction of can be changed.

  Some embodiments have a second position sensor to provide further information regarding the position of the power relay trolley, if desired. For example, the power relay trolley embodiment of FIG. 11 has a first position sensor 400 having an output connected to the first sensor interface module 402 and a second having an output connected to the second sensor interface module 422. A position sensor 420 is provided. The first position sensor 400 is disposed near the front end of the power relay trolley 200, and the second position sensor 420 is disposed near the rear end of the power relay trolley 200. The position sensor can be placed somewhere else in the power relay trolley 200 as needed. The first position sensor interface module 402 has an output signal having a value corresponding to the value of the separation distance L 1 between the sensor 400 and the extension guide rail 410. The second position sensor interface module 422 has an output signal having a value corresponding to the value of the separation distance L 2 between the sensor 420 and the extension guide rail 410. The outputs of the first and second sensor interface modules are connected to the input of the position controller 404. The position controller 404 calculates values corresponding to the distances L1 and L2, and determines an error amount between the path of the power relay trolley 200 and the selected path of the power relay trolley 200. The selected path of power relay trolley 200 is indicated by the arrow labeled D1 in FIGS. In the embodiment of FIGS. 11 and 12, the selected path D <b> 1 is parallel to the extension guide rail 410.

  As shown in FIG. 12, if necessary, the position controller 404 can calculate a value for the deviation angle A1 from the distances L1 and L2. The deflection angle A1 corresponds to the angle between the traveling direction of the power relay trolley 200 and the extension guide rail 410 indicated by the arrow labeled D2 in FIG. The angle A1 further corresponds to the angle between the power relay trolley travel direction D1 and the selected power relay trolley travel direction D1 with respect to the selected travel direction parallel to the extension guide rail 410. The power relay trolley 200 equipped with two position sensors to determine the separation distances L1, L2 and the deflection angle A1 is a path selected with higher accuracy than the power relay trolley having only one position sensor. Can follow. The power relay trolley 200 of FIGS. 11 and 12 can also accommodate a high-voltage cable in the cable groove with higher accuracy than a power relay trolley equipped with only one position sensor. The ability to calculate the deflection angle A1 further includes error conditions in the operation of the power relay trolley 200, such as system guidance error, partial loss of driving wheel traction force, path obstruction due to external causes such as wind or foreign object impact, unevenness There may be advantages in detecting pavement surfaces and other errors. Upon detecting an error condition, the position controller 404 can issue a command to stop the power relay trolley or RTG crane movement or take another action as needed.

  Another means of controlling the position of the power relay trolley is to adapt the power relay trolley to follow a guide signal emanating from a guide wire placed in a groove formed in the pavement. An example of a power relay trolley equipped to follow the induction wire is shown in FIG. The embodiment of FIG. 13 includes a cable reel 204, a high voltage cable 108, a flexible power cable 210, a drive motor 406, and a position controller 404, all corresponding to the elements in the other embodiments described above. A portion of the high voltage cable 108 can be housed in a cable groove 110 as shown in FIG. 11 or in a guide rail embodiment as in FIG. 5 or FIG. Guide wire 414 is received in guide wire groove 412 of pavement 228. Guidance wire 414 defines the path that power relay trolley 200 should follow. An induction signal sensor 416 detects a signal emitted from the induction wire 414. An output signal from the inductive signal sensor 416 is input to the inductive sensor interface module 418. A preferred output from the inductive sensor interface module 418 is a position signal having an intensity that is inversely proportional to the separation distance between the inductive signal sensor 416 and the inductive wire 414. The position controller 404 determines the strength of the position signal and sets the direction of travel of the power relay trolley 200 to maintain the position signal strength at a maximum value corresponding to the power relay trolley that is closely following the chosen path. Issue a control signal to change.

An RTG crane having an on-vehicle high voltage converter connected to an external high voltage source by a high voltage cable as shown in FIG. A block diagram showing a simplified power connection in the RTG crane of FIG. 1 is shown in FIG. In FIG. 14, a high voltage power source having an AC voltage is connected to an input terminal HV _input to a power connection device having a rotating power coupler from a high voltage cable, a cable reel, and a power distribution system on the RTG crane to the power distribution system. Connected. The output from the power connection device is connected to the high voltage input of the transformer T1. As described above for the RTG crane 100 known in the art, the high voltage connection is made directly to the RTG crane 100 and the power connection and high voltage transformer T1 are part of the RTG crane 100. The low voltage AC output from the transformer T1 is connected to the input of the first motor driver / controller MC1 and the input of the second motor driver / controller MC2.

  A motor drive / controller is an analog used herein to convert input voltage / current into a form suitable for powering the electric motor and automatically controlling the rotational speed and direction of the motor. Defined as a combination of circuit and digital circuit. For example, the motor drive / controller may have a rectifier, inverter, or other power control component or power conversion component as required. Those skilled in the art will appreciate that the physical arrangement and functional sharing of the various elements including the motor drive / controller will vary according to the requirements of the particular power relay trolley and RTG crane configuration.

  With continued reference to FIG. 14 for an RTG crane 100 known in the art, the output of the motor drive / controller MC1 is connected to the input of a motor M1 that drives a hoist on the RTG crane 100. The output of another motor drive / controller MC2 is connected to the input of a motor M2 having a drive shaft coupled to drive wheel W1. The encoder E1 connected to the drive shaft of the motor M2 has an output signal indicating the rotational position of the drive wheel W1, and the distance traveled by the drive wheel W1 can be calculated from this output signal. The wheel position signal output from the encoder E1 is an input to the position controller U1. The position sensor interface circuit X1 receives a position reference signal at a terminal Vr, for example, from a differential global positioning system (DGPS) receiver or another high precision position detection device. The position information from the position sensor X1 is connected to the input of the position controller U1. The position controller U1 uses the information from the encoder E1 and the position sensor X1 to accurately establish the location point of the RTG crane for the selected position, such as the position of the cable groove, and then the RTG on the selected path. Issue maneuver correction commands to move to the crane.

A block diagram showing the power connections for one embodiment of the present invention, such as the embodiment of FIG. 4, where low voltage AC power is supplied to the RTG crane from a power relay trolley is shown in FIG. In FIG. 15, the equipment mounted on the power relay trolley is collected in a frame labeled “power relay trolley 200”, and the equipment mounted on the RTG crane is collected in a frame labeled “RTG crane 300”. A high voltage AC power source, for example land power, is connected to a voltage input terminal HV _input on the power relay trolley 200 and then connected to a power connection device such as a high voltage cable on a cable reel or a contactless high voltage power coupler. The The output from the power connection device is connected to the high voltage input on the high voltage step-down transformer T1. The low voltage AC output from the transformer T1 is connected to the output terminal V _output on the power relay trolley 200 and sent by the flexible power cable 210 to the power input terminal V _input on the RTG crane 300.

  In some embodiments, the power relay trolley 200 has an on-board drive motor for propulsion independent of the RTG crane. The power connection and control connection for the drive motor are shown in the power relay trolley 200 frame of FIG. The low voltage AC output from the transformer T1 on the power relay trolley 200 is connected to the motor drive / controller MC3. The power output and control output from the motor drive / controller MC3 are connected to corresponding inputs on the drive motor M3. A drive shaft from the drive motor M3 rotates the drive wheel W2. A wheel position encoder E2 coupled to the shaft of the drive motor M3 generates an output signal corresponding to the rotational position of the drive wheel, and the distance traveled by the drive wheel W2 can be calculated from this output signal. The position controller U2 determines the position for the power relay trolley 200 using the position data from the encoder E2. As described above, if necessary, the position controller U2 can perform another calculation regarding the position of the power relay trolley 200 using a signal from another sensor. In some embodiments, the position controller U2 uses the position to change the direction of travel of the power relay trolley 200 and determine to follow the selected route. In another embodiment, the position controller U2 sends its position on the data terminal Vp on the power relay trolley 200. The output from the position controller U2 is connected to the motor drive / controller MC3 as a control input for establishing closed loop control of the drive wheel W2.

  The flexible signal cable 1502 connects the position data or a signal representing the position data from the data terminal Vp on the power relay trolley 200 to the corresponding data terminal Vp on the RTG crane 300 and then to the position controller U1 on the RTG crane 300. To do. In some embodiments, the position data from the power relay trolley 200 is an input factor in the position control of the RTG crane 300. In some embodiments, the exchange of position data between the power relay trolley 200 and the RTG crane 300 is bidirectional. Such bi-directional exchange of position data may be advantageous for detecting errors in movement or position of the power relay trolley 200 or RTG crane 300, for example, detecting collisions with obstacles.

With continued reference to FIG. 15, the low voltage AC output power from the output terminal V _output on the power relay trolley 200 is connected to the voltage input terminal V _input on the RTG crane 300 by the flexible power cable 210. For example, when it is desirable to disconnect the power relay trolley 200 and the RTG crane 300 from each other for cross lane maneuvers, only the low voltage cables (flexible power cable 210 and flexible signal cable 1502) are disconnected. , Reconnected. The high voltage present at the HV _input on the power relay trolley 200 remains connected to the power relay trolley during normal RTG crane cargo transfer operations.

As shown in FIG. 15, the low voltage AC power on the voltage input terminal V _input of the RTG crane 300 has an output connected to a first motor M1 used to operate the hoist on the RTG crane 300. Connected to the input of the first motor drive / controller MC1. The low voltage AC power is also connected to a second motor drive / controller MC2 having an output connected to a second motor M2 that rotates the drive wheels W1 to propel the RTG crane 300. The encoder E1 connected to the drive shaft of the second motor M2 has an output signal indicating the rotational position of the drive wheel W1, and the distance traveled by the wheel W1 can be calculated from this output signal. The wheel position signal output from the encoder E1 is an input to the position controller U1. The second position sensor interface circuit X1 receives the position reference signal terminal Vr from, for example, a differential global positioning system (DGPS) receiver or another high precision position detection device. The position information from the second position sensor X1 is also provided as an input to the position controller U1. The position controller U1 uses information from the encoder E1 and the position sensor X1 to accurately establish the location point of the RTG crane 300 for a selected position, eg, a reference position on a selected route. The output of the position controller U1 is connected to an input to the motor drive / controller MC2 to establish closed loop control of the drive wheels W1 of the RTG crane 300.

Some RTG cranes have an on-board AC generator driven by a DC motor. The motor-generator pair allows the voltage network on one system (in this case, the RTG crane) to be separated from the voltage network on the other system (eg, a power relay trolley). An example of an RTG crane with an AC generator adapted for operation with a DC motor and a low voltage AC input from a power relay trolley is shown in FIG. In FIG. 16, the low voltage AC power is connected to the power input terminal V _input on the RTG crane 300. The low voltage AC power is the output from a power relay trolley, such as the power relay trolley of FIG. The AC-DC converter CR2 of FIG. 16 has an input connected to the power input terminal V _input . The AC-DC converter is a power conversion circuit for converting AC input power into DC output power. Circuits for converting AC power to DC power are well known in the art, and such circuits can include, for example, rectifiers, inverters, and other electrical circuits. One skilled in the art will appreciate that there are many alternative embodiments of AC-DC converters that can be adapted for use with the present invention. The DC output power from the AC-DC converter CR2 is connected to the input of the DC motor DM1. The DC motor DM1 drives an AC generator ACG1, and the output of the AC generator ACG1 is AC power used by other equipment on the RTG crane.

  In FIG. 16, the AC power from the AC generator ACG1 is connected to the input of the first motor drive / controller MC1. The AC power from the AC generator ACG1 is further connected to the input of the second motor drive / controller MC2. The motor drive / controller and other components shown in FIG. 16 for the RTG crane 300 have the connections and functions as described above for the corresponding components in FIG.

  In another embodiment, the power relay trolley is adapted to output DC power to an RTG crane equipped with an onboard diesel engine and an AC generator. A DC power connection between the power relay trolley and the RTG crane may be useful, for example, for retrofitting power to an RTG crane that was previously powered only by a diesel engine. Alternatively, operate a new RTG crane with a diesel engine and AC generator from a power relay trolley with DC power output so that the RTG crane can perform cross-lane maneuvers without requiring an external high voltage input power source Can be configured.

A power relay trolley adapted to output DC power and an RTG crane equipped with a diesel engine and adapted to operate with DC input power is shown in FIG. In FIG. 17, the AC output of transformer T1 on power relay trolley 200 is connected to the output of AC-DC converter CR6, which has an output that includes a DC power signal. An output from the AC-DC converter CR6 is connected to a DC power output terminal VDC _output on the power relay trolley 200. The description of other components and connections constituting the power relay trolley 200 of FIG. 17 is the same as the description of the corresponding components and connections on the power relay trolley 200 of FIG.

In FIG. 17, the DC output power from the power relay trolley 200 is connected from the DC output power terminal VDC _output to the corresponding DC input power terminal VDC _input on the RTG crane 300. In one embodiment, a flexible power cable 210 adapted for DC voltage / current transmission connects from a VDC _output terminal on the power relay trolley 200 to a terminal VDC _input on the RTG crane 300. The RTG crane 300 further includes a diesel engine that drives an AC generator. The AC power output from the AC generator is connected to the input of an AC-DC converter CR4, and the AC-DC converter CR4 has a DC power output. The DC power output of the AC-DC converter CR4 is connected to the corresponding DC input output terminal VDC _input , thus allowing operation of the RTG crane 300 with power supplied by the power relay trolley 200 or the on-board diesel engine of the RTG crane. . The first motor drive / controller MC1 and the second motor drive / controller MC2 of the RTG crane 300 of FIG. 17 are adapted to accept DC input power. The description of the remaining components and connections shown for the RTG 300 is similar to the description of the corresponding components and connections on the RTG crane 300 of FIG.

  This disclosure is to be taken as illustrative rather than as a limitation on the scope, nature or spirit of the claimed subject matter. Those skilled in the art, after reading this disclosure, will be able to use functionally and / or structurally equivalent substitute elements for the elements described herein, and functional equivalents for the connection aspects described herein. Numerous modifications and variations will become apparent, including the use of various connection aspects or the use of functionally equivalent processes to the processes described herein. Such non-essential variations are to be considered within the scope of the invention contemplated herein. Furthermore, if multiple examples are given for a particular means or process and extrapolation between or outside such given examples is apparent in light of this disclosure, the disclosure is at least as such. Such extrapolation, and thus should be considered to encompass such extrapolation.

  Unless otherwise explicitly stated herein, each ordinary term has its corresponding ordinary meaning within the context of which it is presented, and each ordinary term has its corresponding usual meaning.

108 High Voltage Cable 200 Power Relay Trolley 202 Guide Rail 204 Cable Reel 210 Flexible Power Cable 214 High Voltage Transformer 216 Structure Support 218 Frame Member 220 Guide Roller 224 Guide Roller Assembly 226 Trolley Wheel 228 Pavement 300 Rubber Tire Gantry (RTG) Crane

Claims (25)

In an apparatus for connecting power from a high voltage power grid to a low voltage power input on a mobile crane,
Trolley,
A guidance device attached to the trolley,
A transformer attached to the trolley having a high voltage input and a low power output, the low voltage output having a value selected to power the crane, and receiving power from the high voltage power network; A power input coupler, adapted to be connected to the high voltage input of the transformer,
A device comprising:   The apparatus of claim 1, wherein the power input coupler is adapted to receive power in an inductive manner.   The apparatus of claim 1, wherein the power input coupler is adapted to connect to a high voltage cable.   The apparatus of claim 1, further comprising a rubber tire gantry crane having a low voltage input, wherein the low voltage input of the rubber tire gantry crane is connected to the low voltage output of the trolley. A flexible signal cable connecting the trolley to the rubber tire gantry crane;
A position signal representing the position of the trolley sent by the flexible signal cable; and a position of the rubber tire gantry crane;
Further comprising
The rubber tire gantry crane is adapted to modify the position of the rubber tire gantry crane in response to the position signal;
The apparatus according to claim 4.   A power conversion circuit having an alternating current (AC) input and a direct current (DC) output, wherein the power conversion circuit is inserted in series between the low voltage output and the low voltage input of the transformer, and the rubber tire gantry crane 6. The device of claim 5, wherein the device is adapted to operate at DC current. A cable reel coupled to the trolley in a rotatable manner;
An electrical connection between the power input coupler and the cable reel; and an electrical connection between the cable reel and the high voltage input of the transformer;
The apparatus of claim 3, further comprising: A selected route for the trolley, and a guide rail arranged at a selected separation distance from the selected route;
The apparatus of claim 7, further comprising: A first guide rail side surface, and a second guide rail side surface,
Further comprising
The induction device further comprises an induction roller assembly attached to the power relay trolley;
The induction roller assembly comprises:
Induction roller assembly bracket,
A first induction roller axle attached to the induction roller assembly bracket;
A second induction roller axle attached to the induction roller assembly bracket;
A first induction roller that is assembled to the first induction roller axle in a rotatable manner, and rolls along a side surface of the first induction rail, and is assembled to the second induction roller axle in a rotatable manner. A second guide roller that rolls along the side of the second guide rail;
The apparatus of claim 8 further comprising: A first position sensor attached to the trolley;
A first position sensor output signal representing a first distance of the trolley from the guide rail, and a position controller attached to the trolley;
Further comprising
9. The position controller has a first input connected to the first position sensor output signal and a first output value representative of the first distance from the guide rail. Equipment. The trolley further comprises four wheels;
The position controller has a first control output;
An electric motor controller having a control input and a motor control output connected to the first control output of the position controller; and an electric motor having a rotational speed;
Further comprising
The electric motor is cooperatively connected to at least one of the wheels of the trolley, and the rotational speed of the electric motor is controlled by the motor control output of the electric motor controller. Item 10. The apparatus according to Item 10. A second position sensor attached to the trolley, and a second position sensor output signal representative of a second distance of the trolley from the guide rail;
Further comprising
12. The position controller has a second input connected to the second position sensor output signal and a second output value representative of the second distance from the guide rail. Equipment. The trolley has a direction of travel;
The position controller has a second control output;
A second electric motor controller having a control input and a motor control output connected to the second control output of the position controller; and having a rotational speed and cooperating with at least one of the wheels of the trolley A second electric motor coupled in a manner;
Further comprising
The apparatus of claim 12, wherein the rotational speed of the second electric motor is controlled by the motor control output of the second electric motor controller. A declination output signal representing the selected travel direction of the trolley and an angle between the travel direction of the trolley and the selected travel direction of the trolley from the position controller;
14. The apparatus of claim 13, further comprising:   The position controller controls the first electric motor and the second electric motor to change the traveling direction of the trolley in response to a value of the declination output signal. 14. The apparatus according to 14. In the method of connecting land electric power to a rubber tire gantry crane,
Connecting a terrestrial cable to a high voltage power input on a power relay trolley, and connecting a flexible power cable from a low voltage power output on the power relay trolley to a low voltage power input on the rubber tire gantry crane;
A method comprising the steps of: Disconnecting the rubber tire gantry crane from the flexible power cable; and connecting the rubber tire gantry crane to a second flexible power cable from a second power relay trolley without disconnecting a land power connection;
The method of claim 16, further comprising: Selecting a position for the land electric cable;
Selecting a path for the power relay trolley relative to the position for the land electric cable, and in response to a corresponding movement of the rubber tire gantry crane, the power relay trolley along the selected path Moving,
The method of claim 16, further comprising: Transmitting the position of the power relay trolley to the rubber tire gantry crane; and correcting the position of the rubber tire gantry crane in response to the position of the power relay trolley;
The method of claim 18, further comprising: In rubber tire gantry cranes powered by external power sources,
A power relay trolley having a high voltage input terminal and a low voltage output terminal;
A low voltage input terminal on the rubber tire gantry crane, and a flexible power connection from the low voltage output terminal on the power relay trolley to the low voltage input terminal on the rubber tire gantry crane;
A rubber tire gantry crane comprising:   21. The rubber tire gantry crane of claim 20, wherein disconnecting the rubber tire gantry crane from the external power source does not interrupt the high voltage connection.   The power relay trolley further comprises a transformer having a high voltage input connected to the high voltage input terminal on the power relay trolley and a low voltage output connected to the low voltage output terminal on the power relay trolley. The rubber tire gantry crane according to claim 21. A chosen path for the power relay trolley,
A guide rail having a position relative to the selected path for the power relay trolley, and a guide roller assembly attached to the power relay trolley;
Further comprising
The induction roller assembly comprises:
Induction roller assembly bracket,
A first induction roller axle attached to the induction roller assembly bracket;
A second induction roller axle attached to the induction roller assembly bracket;
A first induction roller assembled in a rotatable manner to the first induction roller axle; and a second induction roller assembled in a rotatable manner to the second induction roller axle;
Further comprising
The first and second guide rollers roll along the guide rail, thus causing the power relay trolley to follow the selected path for the power relay trolley;
The rubber tire gantry crane according to claim 22.   A power conversion circuit having an alternating current (AC) input and a direct current (DC) output, wherein the power conversion circuit is inserted in series between the low voltage output and the low voltage input of the transformer, and the rubber tire gantry crane 24. The rubber tire gantry crane of claim 22, wherein the rubber tire gantry crane is adapted to operate at DC current. The power relay trolley is
A first position sensor having an output signal representative of a first position of the power relay trolley;
A second position sensor having an output signal representative of a second position of the power relay trolley;
Motor with rotation speed,
A motor controller having a control input and an output connected to the motor;
A position controller having a control output connected to the control input of the motor controller, a first input connected to the first position sensor output, and a second input connected to the second position sensor output;
A selected travel direction, and a measured travel direction related to the output signal of the first position sensor and the output signal of the second position sensor;
Further comprising
The position controller changes the motor speed in response to a difference between the measured travel direction and the selected measurement direction;
The rubber tire gantry crane according to claim 22.

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