A self-pre-tightening method and system for the luffing wire rope of a crane

Abstract

The present invention discloses a method and system for self-preloading the luffing wire rope of a crane, which relates to the technical field of floating cranes. It includes symmetrically arranging two lower guiding wide-groove pulleys at the rear of the derrick of the crane, and simultaneously arranging an upper guiding wide-groove pulley at the corresponding position at the head of the derrick. Two luffing wire ropes pass through the upper guiding wide-groove pulley, bypass the lower guiding wide-groove pulley and are respectively fixed. When preloading the luffing wire rope, first place the boom in a resting state, connect the heads of the two luffing wire ropes, the first drum or the second drum winds the rope, and the second drum or the first drum pays out the rope. After the second drum or the first drum finishes paying out the rope, start winding the rope, and the first drum or the second drum pays out the rope according to the set preloading force to realize the preloading of the luffing wire rope. The present invention can realize the preloading of the luffing wire rope by using two luffing drums as preloading winches without relying on external preloading devices.

Description

Technical Field

[0001] The present invention relates to the technical field of floating cranes, and in particular, to a method and system for self-pre-tightening the luffing wire rope of a crane. Background Art

[0002] The luffing mechanism is an important part of a floating crane, which bears heavy loads frequently and has a large rope capacity. Generally, a multi-layer winding drum is used. For a multi-layer winding drum, it is very important to pre-tighten and install the wire rope, which is directly related to the service life of the wire rope. The wire rope at the bottom layer is wound on the drum, and the next layer of wire rope uses the arrangement shape of the previous layer of wire rope as the rope groove. If the previous layer of wire rope does not have enough pre-tightening force during installation, the wire rope will become loose, and the next layer of wire rope may be embedded in the previous layer of wire rope or deeper under load, resulting in phenomena such as wire rope flattening or squeezing, thus damaging the wire rope and even causing the wire rope to be scrapped.

[0003] In the prior art, the method of a pre-tightening force winch is usually adopted. For example, CN110885016B discloses a method for pre-tightening the wire rope of a 250T derrick crane on the ground. The wire rope is directly redirected and tensioned from the head sheave of the A-frame to each winding drum by a tensioning device, and all the wire ropes are fixed in place on the winding drums. After the derrick crane is finally assembled, the wire ropes are directly pulled out by a guide rope and installed in place according to each winding. When the luffing wire rope is wound, the pre-tightening force winch pulls the wire rope according to a certain pre-tightening force, and then the luffing drum winds the wire rope to bring the pre-tightening force. This method requires an additional pre-tightening force winch, and the construction is complex. Especially when the floating crane is built and there is insufficient pre-tightening of the luffing wire rope during use, it is more difficult to provide pre-tightening force by this method, and the pre-tightening cost is high. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a method and system for self-pre-tightening the luffing wire rope of a crane, which can achieve the pre-tightening of the luffing wire rope through the mutual cooperation between two luffing drums without relying on external pre-tightening devices.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] In the first aspect, an embodiment of the present invention provides a method for self-pre-tightening the luffing wire rope of a crane, including:

[0007] Two lower guiding wide-groove pulleys are symmetrically arranged at the rear of the derrick boom of the crane. At the same time, upper guiding wide-groove pulleys are arranged at the corresponding positions at the head of the derrick boom. Two luffing steel wire ropes pass through the upper guiding wide-groove pulleys, bypass the lower guiding wide-groove pulleys and are respectively fixed. When pre-tightening the luffing steel wire ropes, first place the boom in the resting state, connect the heads of the two luffing steel wire ropes, wind the rope on the first drum or the second drum, and pay out the rope on the second drum or the first drum. After the second drum or the first drum finishes paying out the rope, start winding the rope, and the first drum or the second drum pays out the rope according to the set pre-tightening force to realize the pre-tightening of the luffing steel wire ropes.

[0008] As a further implementation method, the two luffing steel wire ropes are connected together by quick-release shackles and pear-shaped wire rope sockets.

[0009] As a further implementation method, before pre-tightening the luffing steel wire ropes, first clamp the luffing steel wire ropes with wire rope clamps. The wire rope clamps are stuck on the safety baffle, then remove the shackle on the ear plate, use the quick-release shackle to connect the two pear-shaped wire rope sockets together, and remove the wire rope clamps and the safety baffle.

[0010] As a further implementation method, the lower guiding wide-groove pulley is provided with a pulley support, and a detachable connection safety baffle is arranged on the pulley support to ensure that the pear-shaped wire rope socket of the steel wire rope cannot pass through.

[0011] As a further implementation method, when the safety baffle is removed, the pear-shaped wire rope socket of the steel wire rope can pass through smoothly.

[0012] As a further implementation method, after pre-tightening, place the joints of the two luffing steel wire ropes in the middle of the two lower guiding wide-groove pulleys, clamp the two luffing steel wire ropes with wire rope clamps respectively, and block them through the safety baffle on the pulley support to prevent the two luffing steel wire ropes from moving.

[0013] As a further implementation method, disconnect the connection of the two luffing steel wire ropes, fix the rope ends on their respective ear plates respectively, and lift the boom after removing the wire rope clamps.

[0014] In a second aspect, an embodiment of the present invention also provides a self-pre-tightening system for the luffing steel wire ropes of a crane, including lower guiding wide-groove pulleys, upper guiding wide-groove pulleys, a first drum, and a second drum. The lower guiding wide-groove pulleys are symmetrically arranged at the rear of the derrick boom of the crane; the upper guiding wide-groove pulleys are arranged at the top of the derrick boom and correspond to the lower guiding wide-groove pulleys one by one; a luffing steel wire rope is wound around each of the first drum and the second drum, and one ends of the two luffing steel wire ropes are connected together after passing through the upper guiding wide-groove pulleys and the lower guiding wide-groove pulleys in sequence.

[0015] As a further implementation method, a pear-shaped wire rope socket is arranged at the end of the luffing steel wire rope, and the pear-shaped wire rope socket is connected to a fixed ear plate through a quick-release shackle.

[0016] As a further implementation method, a pulley support is provided for the lower guiding wide-groove pulley, and a detachable safety baffle is arranged on the pulley support.

[0017] The beneficial effects of the present invention are as follows:

[0018] (1) When pre-tightening the luffing wire ropes of the present invention, first place the boom in a resting state, connect the heads of the two luffing wire ropes, one drum winds the rope, and the other drum pays out the rope. The guiding pulley enables the wire rope joint to pass through smoothly. When one drum finishes paying out the rope, the paying-out drum starts to wind the rope, and the original winding drum starts to pay out the rope according to a certain pre-tightening force, realizing the pre-tightening of the wire ropes on one drum. The same method can be used to realize the pre-tightening of the wire ropes on the other drum. After the pre-tightening is completed, fix the rope heads on their respective fixed ear plates and then lift the boom; the operation is simple and safe, and no additional auxiliary pre-tightening mechanism is required.

[0019] (2) The present invention symmetrically arranges two lower guiding wide-groove pulleys at the rear of the crane A-frame, and at the same time arranges upper guiding wide-groove pulleys at the corresponding heads of the A-frame, which can enable the wire rope joints to pass through smoothly, realizing that the two drums of the luffing mechanism serve as pre-tightening force winches for each other, and solving the problem of difficult pre-tightening of the luffing wire ropes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The schematic diagrams in the specification forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0021] Figure 1 is a side view of the guiding pulley arrangement according to one or more embodiments of the present invention;

[0022] Figure 2 is a front view of the guiding pulley arrangement according to one or more embodiments of the present invention;

[0023] Figure 3 is a schematic diagram of the winding arrangement of the crane luffing wire ropes according to one or more embodiments of the present invention;

[0024] Figure 4 is Figure 3 a partial enlarged schematic diagram at position I in

[0025] Figure 5 is Figure 4 the structure diagram in the P direction in

[0026] FIG. 6(a) and FIG. 6(b) are schematic diagrams of the wire rope splint structure.

[0027] Among them, 1. Lower guiding wide-groove pulley; 2. Upper guiding wide-groove pulley; 3. Pulley support; 4. Steel wire rope clamp; 5. Pear-shaped rope socket; 6. Quick-release shackle; 7. Fixed ear plate; 8. Safety baffle, 9. First drum, 10. Second drum. Specific implementation mode

[0028] Embodiment 1:

[0029] This embodiment provides a method for self-pre-tightening the luffing steel wire rope of a crane. Two lower guiding wide-groove pulleys 1 are symmetrically arranged below the rear of the crane's A-frame, and at the same time, upper guiding wide-groove pulleys 2 are arranged at the corresponding A-frame heads. As Figure 3 shown, the luffing steel wire rope passes through the upper guiding wide-groove pulley 2 and the lower guiding wide-groove pulley 1 in sequence, and the two luffing steel wire ropes are fixed respectively after passing around the lower guiding wide-groove pulley 1.

[0030] When it is necessary to pre-tighten the luffing steel wire rope, first place the boom in the resting state, connect the heads of the two luffing steel wire ropes, one drum winds the rope, and the other drum pays out the rope. The guiding wide-groove pulley enables the steel wire rope joint to pass through smoothly. When one drum finishes paying out the rope, the paying-out drum starts to wind the rope, and the original winding drum starts to pay out the rope according to a certain pre-tightening force, realizing the pre-tightening of the steel wire rope of one drum; the pre-tightening of the steel wire rope of the other drum can be realized in the same way.

[0031] After the pre-tightening is completed, fix the rope ends on their respective fixed ear plates 7 respectively, and then lift the boom. This embodiment solves the problem of difficult pre-tightening of the luffing steel wire rope. Through the setting of the guiding wide-groove pulley, the two drums are used as pre-tightening force winches for each other, realizing the pre-tightening of the luffing steel wire rope. The process is simple and safe to operate, and no additional auxiliary pre-tightening mechanism is required.

[0032] Specifically, it includes the following steps:

[0033] Step 1: Place the boom of the crane on the resting rack. As Figure 3 shown, first use the steel wire rope clamp 4 to clamp the luffing steel wire rope near the pulley support 3. The steel wire rope clamp 4 abuts against one side of the safety baffle 8, so that the luffing steel wire rope cannot move; after installing the steel wire rope clamps 4 on both sides, remove the shackle connected to the fixed ear plate 7, and connect the pear-shaped rope sockets 5 of the two luffing steel wire ropes through the quick-release shackle 6, so that the two luffing steel wire ropes are connected together.

[0034] In this embodiment, the quick-release shackle 6 adopts a C-type quick-release shackle, which is convenient for disassembly.

[0035] Step 2: Remove the steel wire rope clamp 4 and the safety baffle 8 respectively. Taking Figure 2 the shown direction as a reference, the side where the first drum 9 is located is the left side, and the side where the second drum 10 is located is the right side.

[0036] The first reel 9 on the left winds the rope, and the second reel 10 on the right pays out the rope synchronously. The connection points of the two luffing wire ropes pass through the lower guiding wide-groove pulley 1 and the upper guiding wide-groove pulley 2 in sequence. When the second reel 10 on the right has paid out all the rope, the second reel 10 on the right starts to wind the rope, and the first reel 9 on the left pays out the rope. Pay attention to controlling the rope winding and paying-out process of the left and right reels to ensure that the wire rope always has a specified range of pretension force.

[0037] Until the first reel 9 on the left has paid out all the rope; according to the above method, the first reel 9 on the left winds the rope, and the second reel 10 on the right pays out the rope. When the joints of the two wire ropes reach the exact middle between the two lower guiding wide-groove pulleys 1, stop.

[0038] Step Three: Install the safety baffles 8 on both sides respectively. Fix the wire rope splints 4 near the safety baffles 8. After fixing, the two luffing wire ropes pass through the pear-shaped wire rope sockets 5, the quick-release shackles 6 and two shackles respectively and are connected to their respective fixed ear plates 7, and then remove the wire rope splints 4.

[0039] Step Four: Start the luffing mechanism, lift the boom to complete the pre-tensioning of the luffing mechanism wire ropes, and then appropriately adjust the reel control to make the forces on each wire rope balanced when no load is applied.

[0040] This embodiment is particularly applicable to the situation where a crane has two main hooks of different sizes and the two luffing wire ropes may be unevenly stressed when lifting a load.

[0041] Embodiment Two:

[0042] This embodiment provides a self-pre-tensioning system for the luffing wire ropes of a crane, including a lower guiding wide-groove pulley 1, an upper guiding wide-groove pulley 2, a first reel 9, and a second reel 10. As Figure 1 and Figure 2 shown, two upper guiding wide-groove pulleys 2 are arranged at the top of the derrick boom, and two lower guiding wide-groove pulleys 1 are symmetrically arranged below the rear part of the derrick boom, and the lower guiding wide-groove pulleys 1 correspond to the upper guiding wide-groove pulleys 2 one by one.

[0043] A luffing wire rope is wound around each of the first reel 9 and the second reel 10. One ends of the two luffing wire ropes are connected together through a quick-release shackle 6 after passing through the upper guiding wide-groove pulley 2 and the lower guiding wide-groove pulley 1 in sequence.

[0044] As Figure 4 and Figure 5 shown, the lower guiding wide-groove pulley 1 is installed on the pulley support 3. A safety baffle 8 is fixed on one side of the pulley support 3. The arrangement direction of the safety baffle 8 is parallel to the axis direction of the lower guiding wide-groove pulley 1. Ensure that the pear-shaped wire rope socket 5 cannot pass through the safety baffle 8. When the safety baffle 8 is removed, the joints such as the pear-shaped wire rope socket 5 can pass through smoothly.

[0045] In this embodiment, the safety baffle 8 is connected to the pulley support 3 by bolts, which is convenient for disassembly.

[0046] Before pre-tightening the wire ropes, first remove the safety baffle 8. After pre-tightening the wire ropes respectively according to the above method, place the joints of the two wire ropes between the two lower guiding wide-groove pulleys 1, then install the safety baffle 8, and lift the boom. This embodiment is particularly applicable to the situation where the crane has one main hook or two main hooks of the same size, and the two luffing wire ropes are directly connected together, and the load is evenly stressed during hoisting.

[0047] The lower guiding wide-groove pulley 1 and the upper guiding wide-groove pulley 2 in this embodiment enable the wire rope joints to pass through smoothly, and can make the two drums of the luffing drum itself serve as pre-tightening force winches for each other, realizing the pre-tightening of the luffing wire ropes. The process is simple and safe to operate, without the need to rely on additional auxiliary pre-tightening mechanisms. The pre-tightening is not restricted by the site, and can be pre-tightened during off-work hours at sea or during maintenance at the dock. The pre-tightening efficiency is increased by more than 50%.

[0048] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A self-preloading method for the luffing wire rope of a crane, characterized in that, Adopt a luffing wire rope self-preloading system for a crane. The self-preloading system includes: Lower guiding wide-groove pulleys, upper guiding wide-groove pulleys, a first drum, and a second drum. The lower guiding wide-groove pulleys are symmetrically arranged at the rear of the crane's A-frame; the upper guiding wide-groove pulleys are arranged at the top of the A-frame and correspond to the lower guiding wide-groove pulleys one by one; two luffing wire ropes pass through the upper guiding wide-groove pulleys, bypass the lower guiding wide-groove pulleys and are respectively fixed; the lower guiding wide-groove pulleys are provided with pulley supports, and detachable safety baffles are arranged on the pulley supports; a pear-shaped thimble is arranged at the end of the luffing wire rope, and the pear-shaped thimble is connected to a fixed ear plate through a quick-release buckle; the two luffing wire ropes are connected together by a quick-release shackle and a pear-shaped thimble; The self-preloading method includes: Before preloading the luffing wire rope, first clamp the luffing wire rope with a wire rope clip. The wire rope clip is stuck on the safety baffle, then remove the quick-release shackle on the fixed ear plate, use the quick-release shackle to connect the two pear-shaped thimbles together, and remove the wire rope clip and the safety baffle; when the safety baffle is removed, the wire rope pear-shaped thimble can pass through smoothly; When preloading the luffing wire rope, first place the boom in a resting state, connect the heads of the two luffing wire ropes, the first drum or the second drum winds the rope, and the second drum or the first drum pays out the rope; after the second drum or the first drum finishes paying out the rope, start winding the rope, and the first drum or the second drum pays out the rope according to the set preloading force to realize the preloading of the luffing wire rope.

2. A self-pre-tightening method for the luffing wire rope of a crane according to claim 1, characterized in that, After preloading, place the joints of the two luffing wire ropes between the two lower guiding wide-groove pulleys, clamp the two luffing wire ropes with wire rope clips respectively, and prevent the two luffing wire ropes from moving by blocking with the safety baffle of the pulley support.

3. A method for self-pre-tensioning the luffing wire rope of a crane according to claim 2, characterized in that, Disconnect the connection of the two luffing wire ropes, fix the rope ends to their respective fixed ear plates respectively, and lift the boom.

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