EP1194361A1

EP1194361A1 - Trolley moving mechanism in circulating type gantry crane

Info

Publication number: EP1194361A1
Application number: EP00927907A
Authority: EP
Inventors: Man Yop Han
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-05-19
Filing date: 2000-05-19
Publication date: 2002-04-10
Also published as: AU4621200A; KR100306298B1; WO2000069768A1; KR20000074278A

Abstract

A trolley moving mechanism of a circulating type gantry crane including spreaders, hooks which are coupled to the spreaders, movable hoists for lifting the hooks, and trolleys which move along a boom in combination with the spreaders, the trolley moving mechanism characterized in that first and second steel cables for moving the trolleys are installed within the boom in the direction of the length of the boom, and circulate while receiving power from an external source. Also, in the trolley moving mechanism, on each of the trolleys are installed a steel cable holder for coupling a trolley to a steel cable by combination with one of the first and second steel cables, and an unlocker for unlocking a steel cable from the steel cable holder. Furthermore, under the hoist are installed a guide member for pausing the motion of a trolley by separating a steel cable from a steel cable holder by the operation of the unlocker on a trolley which arrives under the hoist, and a moving means for transferring trolleys and spreaders from the first steel cable to the second cable or in the reverse direction while reciprocating between the first and second steel cables. Accordingly, a plurality of trolleys and spreaders move cargo while circulating along a boom, so that the speed of loading and unloading is high. A hoist is pre-positioned and waits at a predetermined location, or is moved to a required location in advance and waits, so that accurate position control required to move cargo in existing cranes is no longer needed. Furthermore, shaking of spreaders is fundamentally prevented, and a reduction in the time taken for accurate position control can remarkably increase the speed of loading/unloading containers.

Description

TROLLEY MOVING MECHANISM IN CIRCULATING TYPE GANTRY CRANE

Technical Field The present invention relates to a circulating type gantry crane or transfer crane which carries freight transportation containers, or a crane having similar functions and operating structures, and more particularly, to a trolley moving mechanism in a circulating type gantry crane, which is configured so that a trolley, a hook and a spreader are selectively separated from or combined with each other, and circulate along a boom

Background Art

Conventional container loading/unloading gantry cranes are designed so that trolleys and spreaders move along a boom horizontally coupled to a main tower pillar, in a state of being suspended by a steel cable In this structure, the steel cable must be reeled in and out to pick up containers and transfer them at a loading/unloading location Thus, a lot of time is required since the movement of trolleys must be accurately controlled in order to load shaking containers at proper locations Also, trolleys must reciprocate between a location from which a container is lifted and a location where a container is laid down, in order to do cargo work, so that speed as well as efficiency significantly decrease

On the other hand, in a horizontal circulating crane in Korean Patent No 134235 and a vertical circulating crane in Korean Patent No 143699, which are previously-registered patents of the present inventor, trolleys and spreaders continuously circulate along a boom Thus, these patented inventions can increase the processing speed to more than three to four times the processing speed of the existing loading and unloading method However, in order to achieve this, a moving system is required, that can achieve transfer while spreaders circulate along a boom Disclosure of the Invention

In order to solve the above problem an objective of the present invention is to provide a trolley moving mechanism in a circulating gantry crane, in which trolleys and spreaders horizontally move containers, hoists and hooks vertically move containers, and in particular, trolleys can be rapidly moved horizontally, independent of the vertical movement of containers by hoists, by coupling the trolleys to a circulating steel cable, so that the loading and unloading speed and efficiency of containers significantly increases

The above objective of the present invention is achieved by a trolley moving mechanism of a circulating type gantry crane including spreaders, hooks which are coupled to the spreaders movable hoists for lifting the hooks, and trolleys which move along a boom in combination with the spreaders, the trolley moving mechanism characterized in that first and second steel cables for moving the trolleys are installed within the boom in the direction of the length of the boom, and circulate while receiving power from an external source Also, in the trolley moving mechanism, on each of the trolleys are installed a steel cable holder for coupling a trolley to a steel cable by combination with one of the first and second steel cables, and an unlocker for unlocking a steel cable from the steel cable holder Furthermore, under the hoist are installed a guide member for pausing the motion of a trolley by separating a steel cable from a steel cable holder by the operation of the unlocker on a trolley which arrives under the hoist and a moving means for transferring trolleys and spreaders from the first steel cable to the second cable or in the reverse direction while reciprocating between the first and second steel cables

The steel cable holder is installed on both sides of a trolley to squeeze a steel cable, and comprises an upper holder member for pressing a steel cable downward, a lower holder member for supporting a steel cable depressed against the upper holder member, and a spring installed between the upper holder member and the lower holder member for biasing the upper holder member and the lower holder member shut The unlocker is installed over the steel cable holder so that it ascends and descends, and comprises a bundling press for pressing down on the upper holder member of the steel cable holder by an external force and making the steel cable holder open, and a wheel installed over the bundling press, such that the wheel is depressed by a guide member and thus forces the bundling press to open the steel cable holder, thereby separating a steel cable from the steel cable holder

The first and second steel cables are usually parallel to each other and positioned over and under the boom, and the moving means is an elevator which is installed at both ends of the boom to ascend and descend between the first and second steel cables

A wheel pressuring member for driving the unlocker is installed in front of the gate of each elevator, and a guide capable of reciprocating in the direction of motion of trolleys is further provided to pull trolleys into the elevator or to push them out of the elevator

Brief Description of the Drawings

FIGS 1 through 3 are views schematically showing the entire structure of a gantry crane adopting a trolley moving mechanism for circulating type gantry crane according to an embodiment of the present invention, to explain the operation of the gantry crane,

FIG 4 is a view showing a hoist, a trolley and a spreader installed on a gantry crane boom, to explain a trolley moving mechanism for a circulating type gantry crane according to an embodiment of the present invention, FIG 5 is a view for explaining the operating relationship among a trolley, a hoist, a hook, and a spreader, and

FIG 6 is a view schematically showing first and second steel cables coupled to a boom to continuously circulate along the boom and elevators installed on both ends of the boom so that they can ascend and descend

Best mode for carrying out the Invention The entire configuration of a gantry crane to which the present invention is applied will now be described before the full-scale description of the present invention

As shown in FIG 1 , in a gantry crane to which a trolley moving mechanism of the present invention is applied, a plurality of trolleys 50 and spreaders 20 coupled to the trolleys 50 move along a boom 100 Also, two hoists 40 are installed on the boom 100 Each of the hoists 40 is connected to a hook 30 via steel cables 114, and is coupled to a spreader 20 to allow the spreader 20 to pick up a container 10 The hoists 40 are moved in advance to locations where containers are to be loaded or unloaded, and stand by, in order to achieve more rapid loading/unloading

One of the two hoists 40 is located on the side of the land, and the other hoist is located on the side of the sea The hoists 40 can move in the directions indicated by arrows a

The hook 30 connected to each of the hoists 40 via the steel cable 114 can ascend and descend by the operation of the hoist 40, so that it is coupled to a spreader 20 to thus pick up a container 10 The container 10 is coupled to the spreader 20 and then lifted up to the height of the trolley 50 and coupled to the same The container 10 in this state is horizontally transferred to a loading/unloading location The horizontal movement of the trolleys 50 is achieved by first and second steel cables 60 and 70 (see FIG 6) which circulate

FIGS 2 and 3 illustrate the operation of loading a container by repeating separation and combination among a hoist 40, a trolley 50 and a hook 30 FIG 2 illustrates an operation in which a trolley and a spreader arrive under the land-side hoist 40 are coupled to the container 10, and then start toward the sea FIG 3 illustrates the operation of a trolley and a spreader arriving under the sea-side hoist 40 For convenience of explanation, several hoists 40 are shown but actually one land-side hoist and one sea-side hoist are installed First, referring to FIG 2, the trolley 50 and the spreader 20 coupled to the lower surface of the trolley 50 move in the direction indicated by arrow b along the boom 100, and are held under the land-side hoist 40 At this time, as described above, the land-side hoist 40 is pre-located and waits directly over the container 10 to be loaded The principle of movement, standstill, and re-starting of the trolley will be described later

When the trolley 50 enters under the land-side hoist 40, the hook 30 descends through the trolley 50 to be coupled to the spreader 20, and then the spreader 20 is separated from the trolley 50 The hook 30 coupled to the spreader 20 as described above keeps descending together with the spreader 20 and reaches the container 10 The spreader 20 is combined with the container 10 The separation and combination of the spreader 20 with the container 10 are achieved by a well- known method After the spreader 20 is completely coupled to the container 10, the hook 30 is retracted by the land-side hoist 40 When the spreader 20 arrives under the trolley 50 by the continuous ascending of the hook 30, the trolley 50 is coupled to the spreader 20 and then the hook 30 is separated from the spreader 20 The hook 30 separated from the spreader 20 further ascends at the original location and waits for the next trolley 50 Thereafter, the trolley 50 moves in the direction indicated by arrow c in a state of being combined with a spreader and a container

Referring to FIG 3, the trolley 50 moving in the direction indicated by arrow c stops under the sea-side hoist 40 which has been pre-located and is waiting directly over the position at which a container is to be loaded

When the trolley 50 arrives under the sea-side hoist 40, the hook 30 waiting under the hoist 40 passes through the trolley 50 and is coupled to the spreader 20 Then, the spreader 20 is separated from the trolley 50

When the spreader 20 is separated from the trolley 50, and the spreader 20 coupled to the hook 30 continues to descend and finally reaches a loading location, it is separated from the container 10, thereby completing loading of a container

The spreader 20 separated from the container again ascends together with the hook 30 to be re-coupled to the trolley 50, and is then separated from the hook 30 The spreader 20 in this state moves along the boom in the direction indicated by arrow d

As described later, the trolley 50, which arrived almost at the end of the boom 100 by moving in the direction indicated by arrow d, is released from the first steel cable 60 of FIG 6, and then loaded on a sea-side elevator 80 of FIG 6 and lifted Then, the lifted trolley 50 is coupled to the second steel cable 70 of FIG 6, moves toward the land in this state, descends by the operation of a land-side elevator 80 of FIG 6, and is then re-coupled to the first steel cable 60 In this way, a closed-loop operation wherein the operations of FIGS 2 and 3 are repeated is performed

Consequently, in a gantry crane according to the present invention, combination and separation between a trolley and a spreader and between the spreader and a hook are repeated, and the trolley 50 and the spreader 20 rapidly move while engaged with the steel cables 60 and 70

FIG 4 is a view for explaining a trolley moving mechanism of a circulating type gantry crane according to the present invention As shown in FIG 4, a boom 100 is split into two parts, and the two parts are separated so that a hoist 40 and a trolley 50 move in the inner space therebetween A trolley track 102 for supporting a trolley wheel 59 installed on the trolley 50 is formed on the lower inner surface of each of the two parts of the boom 100 A hoist track 104 for providing a moving path for the hoist 40 is formed on the middle inner surface of each of the two parts of the boom 100

A power line track (not shown) is provided to support a power line for providing power to the hoist 40 A spreader track 106 for supporting the wheel of the spreader 20 when the trolley 50 is turned back is formed at the top of the boom 100 A hook 30 is suspended from the hoist 40 so that it ascends and descends along a steel cable The hook 30 is normally retracted as much as possible so that the trolley 50 can pass under the hook 30

In FIG 4, a trolley 50 positioned under the hoist 40 moves along the motion trajectories shown in FIGS 2 and 3 in combination with the first steel cable 60 of FIG 6, and a trolley 50 positioned over the hoist 40 is in a state of being turned back in combination with the second steel cable 70 of FIG. 6 A steel cable holder 52 for holding each of the first and second steel cables 60 and 70 is installed protruding from both ends of the trolley 50. The steel cable holder 52 couples the trolley 50 to the steel cables 60 and 70 by squeezing the outer circumference of each of the steel cables 60 and 70 The steel cable holder 52 is installed at the lateral side of the trolley 50, and includes an upper holder member 52a for squeezing the steel cables 60 and 70 downward, a lower holder member 52b for squeezing the steel cables 60 and 70 upward, and a spring 54 installed between the holder members 52a and 52b for biasing the holder members 52a and 52b shut The holder members 52a and 52b are pivotally coupled to each other by a support pin 52c In particular, at the rear portion of the upper holder member 52a is a curved portion 85 A bundling press 57 is installed over the curved portion 85 so that it ascends and descends Accordingly, when the bundling press 57 presses the curved portion 85 in the direction indicated by arrow f, the leading portion of the holder member 52a pivots in the direction indicated by arrow g against the force of the spring 54, so that the trolley 50 is separated from each of the steel cables 60 and 70

An unlocker 56 for unlocking the steel cables 60 and 70 from the steel cable holder 52 is installed over the steel cable holder 52 The unlocker 56 is made up of the bundling press 57 for pressing down on the holder member 52a, and a wheel 58 for pressing down on the bundling press 57 The bundling press 57 and the wheel 58 are installed on the trolley 50 so that they ascend and descend In particular, the wheel 58 is pressed down by a guide member 42 of FIG 5 and a wheel pressing member 43 of FIG 6 while moving together with the trolley 50, and makes the bundling press 57 depress the holder member 52a Meanwhile, spreader wheels 22 are installed on the right and left sides of the front side and on the right and left sides of the rear side on the lower portion of the spreader 20 A guider 24 is installed on the outer side of each of the spreader wheels 22, and guides a container 10 when the spreader 20 is combined with the container 10 Also when the spreader 20 moves along the boom 100, the guider 24 pivots toward the inside in the direction indicated by arrow h and remains in a folded state in order to allow the spreader 20 to move without obstruction

It can be seen from the trolley 50 and spreader 20 shown at the upper portion of FIG 5 that the spreader wheel 22 rolls on the spreader track 106, and the guider 24 is folded toward the inside Also, if the height and position of the spreader track 106 are changed, the trolley 50 and the spreader 20 can be moved using the trolley wheel 59 instead of the spreader wheel 22

FIG 5 shows a trolley which has arrived under a hoist, and a trolley which is turning back along the spreader track of a boom As shown in FIG 5, while a trolley 50 is moving along a trolley track 102, suspended by the steel cable 60, it is held under the hoist 40 This is achieved by separating the trolley 50 from the steel cable 60 by opening the steel cable holder 52 while the trolley 50 is coming into position under the hoist 40 Also, in order to separate the trolley from the steel cable 60, a guide member 42 for pressing down on an arrived trolley wheel 58 is installed under the hoist 40 The guide member 42, which is fixed under the hoist 40, is designed so that the height (y2) at the central portion is smaller than the height (y1 ) at both ends The height (y1 ) is the height of a wheel 58 which is not depressed, and the height (y2) is the height of the wheel 58 which has completely depressed the holder member 52a

The center portion of the guide member 42 is made level, and the portion between the center portion and each end is smoothly curved, such that the wheel 58 easily ascends and descends while moving together with the trolley 50

Finally, while the trolley 50 passes under the hoist 40 the wheel 58 presses down on the unlocker 56 of the trolley 50, so that the steel cable holder 52 is completely separated from the steel cable 60

When the trolley 50 is placed under the hoist 40, the holder 52 is completely separated from the steel cable 60, and thus the trolley is held During that time, the trolley 50 lifts or lays down the container 10

After the container 10 is lifted and coupled to the bottom surface of the spreader 20, the trolley 50 is released from the hoist 40 and starts moving again This is achieved by the forward pushing of the trolley 50 waiting under the hoist 40 by the next trolley 50 When the trolley 50 is pushed out of the area under the hoist 40, the wheel 58 disconnects from the guide member 42, and the position of the unlocker 56 is restored upward, so that the force in the direction indicated by arrow f of FIG 4 is removed Thus, the upper holder member 52a pivots back toward the lower holder member 52b by the force of the spring 54, and thus the steel cable holder 52 is re-coupled to the steel cable 60 The trolley 50 coupled to the steel cable 60 in this way moves to a loading position at the same speed as the steel cable 60

A trolley which has arrived under a hoist 40 over an unloading position is separated from the steel cable 60 by the same method as described above, and unloads a container

FIG 6 shows two steel cables 60 and 70 within the gantry crane boom, and an elevator 80 for moving a trolley and a spreader between the two steel cables As shown in FIG 6, the first steel cable 60 is installed in the direction of the length of a boom 100, and continuously circulates The second steel cable 70 is parallel to the first steel cable 60, and continuously circulates over the first steel cable 60 The first and second steel cables 60 and 70 are circulated by the force of a motor (not shown)

The first steel cable 60 is for moving a trolley 50 and a spreader 20 to move cargo as shown in FIGS 2 and 3, and the second steel cable 70 is for turning the trolley 50 which has completed loading or unloading back to the land Since these steel cables must be arranged in straight lines, it is preferable that support rollers 72 are intermittently installed on the boom to prevent the steel cables 60 and 70 from drooping

Elevators 80 are installed at both ends of the first and second steel cables 60 and 70 The elevators 80 are manufactured to be large enough to accommodate the trolley 50 coupled to the spreader 20 in its entirety, and ascend and descend by the force of an elevating motor (not shown)

A trolley, which has arrived at the right end of the steel cable 60 in a state of being coupled to the first steel cable 60, is separated from the steel cable 60 by a method to be described later, loaded on the elevator 80, and then elevated in the direction indicated by arrow A When the elevator 80 ascends and reaches the end of the second steel cable 70, the trolley 50 and the spreader 20 coupled to the trolley 50 are unloaded from the elevator and loaded on the second steel cable 70, coupled to the second steel cable 70, and pulled along The trolley 50 and the spreader 20, which has arrived at the left end of the boom 100 along the second steel cable 70, are lowered in the direction indicated by arrow B using another elevator 80, and then re-coupled to the first steel cable 60

A hook-shaped guide 82 capable of moving forward and backward is installed below the door of the elevator 80 The hook-shaped guide 82 pulls a trolley 50 into the elevator 80 and pushes a trolley out of the elevator 80, using its hook structure The guide 82 can be driven by several commonly- known methods

The wheel pressing member 43 for pressing down on the wheel 58 is fixedly installed in front of the door of the elevator 80 The wheel pressing member 43 has the same function as the guide member 42 installed under the hoist 40 That is, since the wheel pressing member 43 is installed in front of the elevator 80, it presses down on the upper holder member 52a when a trolley arrives in front of the elevator 80 Thus, the trolley is held, and the steel cable holder 52 is completely separated from each of the steel cables 60 and 70 Accordingly, when the trolley 50 which has completed loading or unloading a container, reaches the front of the elevator 80, it is separated from the steel cable 60 and held, and moved into the elevator 80 by being pulled by the guide 82 The trolley and the spreader loaded on the elevator 80 are lifted, pushed out of the elevator 80 using the guide 82, and then coupled to the second steel cable 70

Meanwhile, the holder members 52a and 52b, which are separated from the steel cables 60 and 70 and loaded on the elevator 80, are kept open In order to achieve this, the wheel pressuring member 43 is horizontally extended into the elevator 80 The leading end of the wheel pressuring member 43 is extended so that its curved portion 88 is placed over each of the steel cables 60 and 70, in order that the holder members 52a and 52b of the trolley 50 pushed out of the elevator 80 may be pursed in a state where the steel cables 60 and 70 are placed within the steel cable holder 52 As described above, the trolley 50 coupled to the second steel cable

70 is moved to the land-side elevator 80 lowered by undergoing the above- described steps, and re-coupled to the first steel cable 60

The drawings and specification which are just an example of the present invention, are provided not to restrict the meaning or scope of the present invention defined by the accompanying claims, but to explain the present invention The mechanism in which a trolley and a spreader move along a boom through separation or combination between the trolley and the spreader and between a hook and the spreader, must be construed as being encompassed within the scope of the present invention

Industrial Applicability

In the present invention configured and operated as described above, a plurality of trolleys and spreaders move cargo while circulating along a boom, so that the speed of loading and unloading is high Also, a hoist is pre- positioned and waits at a predetermined location, or is moved to a required location in advance and waits so that accurate position control required to do cargo work with existing cranes is no longer needed Furthermore, shaking of spreaders is fundamentally prevented, and a reduction in the time for accurate position control can remarkably increase the speed of loading/unloading containers

Claims

What is claimed is

1 A trolley moving mechanism of a circulating type gantry crane including spreaders, hooks which are coupled to the spreaders, movable hoists for lifting the hooks, and trolleys which move along a boom in combination with the spreaders the trolley moving mechanism characterized in that first and second steel cables for moving the trolleys are installed within the boom in the direction of the length of the boom, and circulate while receiving power from an external source on each of the trolleys are installed a steel cable holder for coupling a trolley to a steel cable by combination with one of the first and second steel cables, and an unlocker for unlocking a steel cable from the steel cable holder, and under the hoist are installed a guide member for pausing the motion of a trolley by separating a steel cable from a steel cable holder by the operation of the unlocker on a trolley which arrives under the hoist, and a moving means for transferring trolleys and spreaders from the first steel cable to the second cable or in the reverse direction while reciprocating between the first and second steel cables

2 The trolley moving mechanism of a circulating type gantry crane of claim 1 , wherein the steel cable holder 52 is installed on both sides of a trolley 50 to squeeze a steel cable, and comprises an upper holder member for pressing a steel cable downward, a lower holder member for supporting a steel cable depressed against the upper holder member, and a spring installed between the upper holder member and the lower holder member for biasing the upper holder member and the lower holder member shut

3 The trolley moving mechanism of a circulating type gantry crane of claim 2, wherein the unlocker is installed over the steel cable holder so that it ascends and descends and comprises a bundling press for pressing down on the upper holder member of the steel cable holder by an external force and making the steel cable holder open, and a wheel installed over the bundling press, such that the wheel is depressed by a guide member and thus forces the bundling press to open the steel cable holder, thereby separating a steel cable from the steel cable holder

4 The trolley moving mechanism of a circulating type gantry crane of claim 1 , wherein the first and second steel cables are usually parallel to each other and positioned over and under the boom, and the moving means is an elevator which is installed at both ends of the boom to ascend and descend between the first and second steel cables

5 The trolley moving mechanism of a circulating type gantry crane of claim 4, wherein a wheel pressuring member for driving the unlocker is installed in front of the gate of each elevator, and a guide capable of reciprocating in the direction of motion of trolleys is further provided to pull trolleys into the elevator or to push them out of the elevator