阅读说明：本技术 伸缩式主臂桅杆、起重机及其操作方法 (Telescopic main arm mast, crane and operation method thereof ) 是由 郭晓晨 焦战方 石磊庭 于 2020-06-30 设计创作，主要内容包括：本发明提供了一种伸缩式主臂桅杆、起重机及其操作方法,涉及起重机技术领域,包括多级依次滑动连接的伸缩支架；相邻两个伸缩支架的相接处设置有驱动机构,驱动机构的一端与一个伸缩支架连接,驱动机构的另一端与另一个伸缩支架连接,驱动机构能够驱动相邻两个伸缩支架的展开与收缩。与现有技术相比,本发明提供的伸缩式主臂桅杆通过多级依次滑动连接的伸缩支架和驱动机构实现主臂桅杆在其长度方向上的伸缩,在收缩状态下实现伸缩式主臂桅杆的扳起,然后再通过驱动机构实现伸缩式主臂桅杆的展开,避免了主臂桅杆在扳起过程中因自重而承受极大弯矩,造成主臂桅杆的材料失效和损坏,影响起重机正常使用的风险。(The invention provides a telescopic main arm mast, a crane and an operation method thereof, relating to the technical field of cranes and comprising a plurality of stages of telescopic supports which are sequentially connected in a sliding manner; the joint of two adjacent telescopic supports is provided with actuating mechanism, and actuating mechanism's one end and a telescopic support are connected, and actuating mechanism's the other end and another telescopic support are connected, and actuating mechanism can drive the expansion and the shrink of two adjacent telescopic supports. Compared with the prior art, the telescopic main arm mast provided by the invention has the advantages that the telescopic main arm mast is telescopic in the length direction through the telescopic supports and the driving mechanisms which are sequentially connected in a sliding manner in a multi-stage manner, the telescopic main arm mast is lifted in a contracted state, and then the telescopic main arm mast is unfolded through the driving mechanism, so that the risk that the main arm mast bears a great bending moment due to self weight in the lifting process, the material of the main arm mast is invalid and damaged, and the normal use of a crane is influenced is avoided.)

1. A telescopic main arm mast is characterized by comprising a plurality of stages of telescopic supports which are sequentially connected in a sliding manner;

adjacent two the department of meeting of telescopic bracket is provided with actuating mechanism, actuating mechanism's one end and adjacent two one in the telescopic bracket connects, actuating mechanism's the other end and adjacent two another in the telescopic bracket connects, actuating mechanism can drive adjacent two telescopic bracket's expansion and shrink.

2. The telescopic mast according to claim 1, wherein the drive mechanism is a telescopic cylinder (130).

3. The telescopic mast according to claim 2, characterized in that the telescopic cylinder (130) is arranged inside the telescopic support.

4. The telescopic mast of claim 2, wherein one end of the telescopic cylinder (130) is hinged to one of the two adjacent telescopic supports and the other end of the telescopic cylinder (130) is hinged to the other of the two adjacent telescopic supports.

5. The telescopic mast according to claim 3, wherein the number of telescopic supports is two, respectively a first support (110) and a second support (120);

the first bracket (110) comprises two first cross beams (111) arranged at intervals, and the second bracket (120) comprises two second cross beams (121) arranged at intervals;

one end of the second cross beam (121) is used for being connected with a rotary table (400), and the other end, far away from the rotary table (400), of the second cross beam (121) is inserted into an inner cavity of the first cross beam (111) and can slide along the extending direction of the first cross beam (111);

the telescopic cylinder (130) is arranged in an inner cavity of the first cross beam (111).

6. The telescopic mast according to claim 5, wherein the first beam (111) and the second beam (121) are rectangular or circular in cross-section.

7. The telescopic mast according to any one of claims 2-6, wherein the telescopic cylinder (130) is a hydraulic or pneumatic cylinder.

8. A crane, comprising a turntable (400), a jacking mechanism (500), a luffing mechanism, a pulling plate (300), a boom (200) and a telescopic main boom mast (100) according to any one of claims 1 to 7;

one end of the telescopic main arm mast (100) is rotatably connected with the rotary table (400); one end of the jacking mechanism (500) is connected with the rotary table (400), and the other end of the jacking mechanism is connected with the telescopic main arm mast (100);

one end of the arm support (200) is rotatably connected with the rotary table (400), and the other end of the arm support (200) is connected with one end, far away from the rotary table (400), of the telescopic main arm mast (100) through the pulling plate (300);

the luffing mechanism is connected with one end, far away from the rotary table (400), of the telescopic main arm mast (100) and used for driving the telescopic main arm mast (100) to rotate.

9. A method of operating a crane, comprising the steps of:

driving a telescopic main arm mast (100) to reach a set position by using a jacking mechanism (500);

when the telescopic main arm mast (100) reaches a set position, driving the telescopic main arm mast (100) to extend to a preset length by using a driving mechanism;

when the telescopic main arm mast (100) extends to a preset length, connecting the arm support (200) and one end, far away from the rotary table (400), of the telescopic main arm mast (100) through a pulling plate (300);

the telescopic main arm mast (100) is driven to rotate through a luffing mechanism, and the arm support (200) is lifted.

10. Method of operating a crane according to claim 9, wherein the telescopic jib mast (100) is set in such a way that the angle between the extension of the telescopic jib mast (100) and the horizontal plane satisfies: 60 to 120 degrees.

Technical Field

The invention relates to the technical field of cranes, in particular to a telescopic main arm mast, a crane and an operation method of the crane.

Background

In the existing crane industry, a main arm mast of a crane is used for raising the arm of an arm support, and the length, strength and rigidity of the main arm mast play key roles in raising the arm capacity of the crane.

As shown in fig. 1 and 2, the bottom end of the conventional main jib mast 10 is hinged to a rotary table of a crane, one end of the boom 20 is also hinged to the rotary table, the top end of the main jib mast 10 is connected to one end of the boom 20 far away from the rotary table through a pulling plate 30, and the main jib mast 10 is driven to rotate by a hoisting mechanism arranged on the rotary table and opposite to the boom 20, so that the boom 20 is hoisted. If the arm support 20 is to be raised, the main arm mast 10 is raised first, and the main arm mast 10 is raised by a lift cylinder provided on the turntable. As shown in FIG. 3, when the mast 10 of the main jib is pulled up, the jacking cylinder generates an upward jacking force F₂The jacking force needs to overcome the dead weight G of the mast of the main arm₂Assuming that the horizontal distance between the center of gravity of the jib mast 10 and the pivot of the jib mast 10 is L₂The dead weight of the main arm mast 10 generates a bending moment M to the main arm mast₂＝G₂×L₂That is, the main arm mast 10 is subjected to a bending moment M caused by its own weight during the turning-up process₂. In the jacking cylinder force F₂The nearby main arm mast bears a great bending moment, and when the bending moment is great, the material failure of the main arm mast 10 can be caused, such as local plastic deformation and even local tearing damage, so that the main arm mast 10 is damaged, and the normal use of the crane is influenced.

Disclosure of Invention

The invention aims to provide a telescopic main arm mast, a crane and an operation method thereof, which solve the technical problems that the main arm mast of the traditional crane bears a great bending moment near a jacking oil cylinder in the process of pulling up the main arm mast, and the material failure of the main arm mast can be caused when the bending moment is great, such as the damage of local plastic deformation and even local tearing and the like, so that the main arm mast is damaged and the normal use of the crane is influenced.

The invention provides a telescopic main arm mast, which comprises a plurality of stages of telescopic supports which are sequentially connected in a sliding manner;

the joint of two adjacent telescopic supports is provided with actuating mechanism, and actuating mechanism's one end and one telescopic support in two adjacent telescopic supports are connected, and actuating mechanism's the other end and another telescopic support in two adjacent telescopic supports are connected, and actuating mechanism can drive the expansion and the shrink of two adjacent telescopic supports.

Further, the driving mechanism is a telescopic cylinder.

Further, the telescopic cylinder is arranged inside the telescopic support.

Furthermore, one end of the telescopic cylinder is hinged with one of the two adjacent telescopic supports, and the other end of the telescopic cylinder is hinged with the other of the two adjacent telescopic supports.

Furthermore, the number of the telescopic supports is two, namely a first support and a second support;

the first support comprises two first cross beams arranged at intervals, and the second support comprises two second cross beams arranged at intervals;

one end of the second cross beam is used for being connected with the rotary table, and the other end, far away from the rotary table, of the second cross beam is inserted into the inner cavity of the first cross beam and can slide along the extending direction of the first cross beam;

the telescopic cylinder is arranged in the inner cavity of the first cross beam.

Further, the cross section of the first beam and the second beam is rectangular or circular.

Further, the telescopic cylinder is a hydraulic cylinder or an air cylinder.

The crane provided by the invention comprises a rotary table, a jacking mechanism, a luffing mechanism, a pulling plate, an arm support and a telescopic main arm mast;

one end of the telescopic main arm mast is rotatably connected with the rotary table; one end of the jacking mechanism is connected with the rotary table, and the other end of the jacking mechanism is connected with the telescopic main arm mast;

one end of the arm support is rotatably connected with the rotary table, and the other end of the arm support is connected with one end, far away from the rotary table, of the telescopic main arm mast through a pulling plate;

the amplitude changing mechanism is connected with one end, far away from the rotary table, of the telescopic main arm mast and is used for driving the telescopic main arm mast to rotate.

The invention provides an operation method of a crane, which comprises the following steps:

driving a telescopic main arm mast to a set position by using a jacking mechanism;

when the telescopic main arm mast reaches a set position, the telescopic main arm mast is driven by a driving mechanism to extend to a preset length;

when the telescopic main arm mast extends to a preset length, the arm support is connected with one end, far away from the rotary table, of the telescopic main arm mast through the pulling plate;

the amplitude variation mechanism drives the telescopic main arm mast to rotate and carries out the turning-up action of the arm support.

Further, the setting position of the telescopic main boom mast is such that an included angle between the extension direction of the telescopic main boom mast and a horizontal plane satisfies: 60 to 120 degrees.

The invention provides a telescopic main arm mast, which comprises a plurality of stages of telescopic supports which are sequentially connected in a sliding manner; the joint of two adjacent telescopic supports is provided with actuating mechanism, and actuating mechanism's one end and one telescopic support in two adjacent telescopic supports are connected, and actuating mechanism's the other end and another telescopic support in two adjacent telescopic supports are connected, and actuating mechanism can drive the expansion and the shrink of two adjacent telescopic supports.

Compared with the prior art, the telescopic main arm mast provided by the invention can realize the telescopic of the main arm mast in the length direction through the multi-stage telescopic bracket and the driving mechanism which are sequentially connected in a sliding manner, can realize the lifting of the telescopic main arm mast in a contraction state, and then realizes the unfolding of the telescopic main arm mast through the driving mechanism, so that the risk that the main arm mast bears a great bending moment due to self weight in the lifting process, the material of the main arm mast is invalid and damaged, and the normal use of a crane is influenced is avoided.

The crane provided by the invention comprises a rotary table, a jacking mechanism, a luffing mechanism, a pulling plate, an arm support and a telescopic main arm mast; one end of the telescopic main arm mast is rotatably connected with the rotary table; one end of the jacking mechanism is connected with the rotary table, and the other end of the jacking mechanism is connected with the telescopic main arm mast; one end of the arm support is rotatably connected with the rotary table, and the other end of the arm support is connected with one end, far away from the rotary table, of the telescopic main arm mast through a pulling plate; the amplitude changing mechanism is connected with one end, far away from the rotary table, of the telescopic main arm mast and is used for driving the telescopic main arm mast to rotate.

The telescopic main arm mast in a contraction state is pulled up through the jacking mechanism, then the telescopic main arm mast is unfolded, the arm support and the telescopic main arm mast are connected through the pulling plate, and the telescopic main arm mast is driven to rotate by the luffing mechanism, so that the pulling up of the arm support is realized, the bending deformation and failure of the main arm mast are avoided, meanwhile, the stress of the arm support and the pulling plate can be effectively improved due to the increase of the length of the telescopic main arm mast, and the stability of the crane is improved.

The invention provides an operation method of a crane, which comprises the following steps: driving a telescopic main arm mast to a set position by using a jacking mechanism; driving the telescopic main arm mast to extend to a preset length by using a driving mechanism; connecting the arm support and one end of the telescopic main arm mast far away from the rotary table through a pulling plate; the amplitude variation mechanism drives the telescopic main arm mast to rotate and carries out the turning-up action of the arm support.

The telescopic main arm mast is driven to a preset length after being driven to a set position through the jacking mechanism, and then the telescopic main arm mast is driven to rotate through the amplitude variation mechanism, so that the arm support is lifted. The bending failure of the mast of the main arm is avoided, meanwhile, under the condition that the crane does not have the super-lifting device, the requirement on the power of the luffing mechanism is reduced, the axial force of the pulling plate acting on the arm support is reduced, and the risk of buckling instability of the arm support is reduced, so that the crane can pull up a longer arm support.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic diagram of a prior art crane without a super lift apparatus for lifting a boom;

FIG. 2 is a block diagram of a prior art primary jib mast;

FIG. 3 is a schematic diagram of the stress of the existing main jib mast when it is pulled up;

FIG. 4 is a schematic view of the stress when the conventional arm support is pulled up;

FIG. 5 is a schematic drawing showing the pulling plate of FIG. 4 in an exploded view;

FIG. 6 is a schematic view of the arm support bending under an axial force;

FIG. 7 is a block diagram of a telescoping mast head provided by an embodiment of the present invention;

FIG. 8 is a comparative illustration of the expansion and contraction of a telescoping mast head mast provided by an embodiment of the present invention;

fig. 9 is a schematic diagram of a lying state of a telescopic jib mast of a crane according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of the raising of a telescopic jib mast of a crane according to an embodiment of the present invention;

FIG. 11 is a schematic view of the extension of the telescopic jib mast of the crane according to the present invention;

fig. 12 is a schematic diagram of a crane boom raising apparatus according to an embodiment of the present invention;

FIG. 13 is a graph comparing the pulling force of the pulling plate when the telescopic jib mast of the crane is extended and retracted according to the embodiment of the invention;

fig. 14 is a tension exploded view of the pulling plate of fig. 13.

Icon: 10-a main jib mast; 20-a boom; 30-pulling a plate;

100-a telescopic main arm mast; 110-a first support; 111-a first beam; 120-a second scaffold; 121-a second beam; 130-telescoping cylinder; 200-arm support; 300-pulling a plate; 400-a turntable; 500-a jacking mechanism; 610-amplitude-variable winding; 620-main arm mast pulley block; 630-a turntable pulley block; 640-amplitude-variable steel wire rope.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 7 and 8, the telescopic main boom mast 100 provided in this embodiment includes a plurality of stages of telescopic supports that are sequentially slidably connected; the joint of two adjacent telescopic supports is provided with actuating mechanism, and actuating mechanism's one end and one telescopic support in two adjacent telescopic supports are connected, and actuating mechanism's the other end and another telescopic support in two adjacent telescopic supports are connected, and actuating mechanism can drive the expansion and the shrink of two adjacent telescopic supports.

Compared with the prior art, the telescopic main arm mast 100 provided by the invention realizes the extension and contraction of the main arm mast in the length direction thereof through the multi-stage telescopic bracket and the driving mechanism which are sequentially connected in a sliding manner, the telescopic main arm mast 100 can be pulled up in a contraction state, and then the telescopic main arm mast 100 is unfolded through the driving mechanism, so that the risk that the material of the main arm mast fails and is damaged and the normal use of a crane is influenced because the main arm mast with the fixed length bears a great bending moment due to dead weight in the pulling up process is avoided.

Further, the driving mechanism is a telescopic cylinder 130, and one end of the telescopic cylinder 130 is connected with one of the two adjacent telescopic supports; the other end of the telescopic cylinder 130 is connected with the other telescopic bracket of the two adjacent telescopic brackets.

Specifically, in this embodiment, the driving mechanism is a telescopic cylinder 130, the telescopic cylinder 130 is disposed between two adjacent telescopic brackets, a fixed end of the telescopic cylinder 130 is connected to one of the two adjacent telescopic brackets, a movable end of the telescopic cylinder 130 is connected to the other of the two adjacent telescopic brackets, and the expansion and contraction of the telescopic main arm mast 100 are realized by the expansion and contraction of the telescopic cylinder 130.

It should be noted that the driving mechanism may also be composed of a driving motor, a steel wire rope and a pulley assembly, and the driving motor drives the steel wire rope and the pulley assembly to achieve the extension and retraction of the telescopic main arm mast 100, for example, the mechanism for achieving the extension and retraction of the boom 200 on a telescopic boom crane may be used.

Further, a telescopic cylinder 130 is provided inside the telescopic bracket.

Specifically, in order to reduce the space occupation, the telescopic bracket may have a hollow structure, and the telescopic cylinder 130 may be disposed inside the telescopic bracket.

Further, one end of the telescopic cylinder 130 is hinged to one of the two adjacent telescopic supports, and the other end of the telescopic cylinder 130 is hinged to the other of the two adjacent telescopic supports.

In this embodiment, the telescopic cylinder 130 is disposed inside the telescopic bracket, one end of the telescopic cylinder 130 is hinged to one of the two adjacent telescopic brackets, and the other end of the telescopic cylinder 130 is hinged to the other telescopic bracket.

Further, the number of the telescopic brackets is two, and the telescopic brackets are respectively the first bracket 110 and the second bracket 120; the first bracket 110 comprises two first cross beams 111 arranged at intervals, and the second bracket 120 comprises two second cross beams 121 arranged at intervals; one end of the second cross beam 121 is used for being connected with the turntable 400, and the other end of the second cross beam 121, which is far away from the turntable 400, is inserted into the inner cavity of the first cross beam 111 and can slide along the extending direction of the first cross beam 111; a telescopic cylinder 130 is arranged in the inner cavity of the first beam 111.

Specifically, the telescopic main arm mast 100 is two-stage, that is, the telescopic main arm mast is composed of a first support 110 and a second support 120, the first support 110 includes two first beams 111 arranged at intervals, the length direction of the first beams 111 is the same as that of the telescopic main arm mast 100, the second support 120 includes two second beams 121 arranged at intervals, the second beams 121 are inserted into the inner cavity of the first beams 111 and can slide in the length direction of the first beams 111 relative to the first beams 111, the telescopic cylinder 130 is arranged in the inner cavity of the first beams 111, one end of the telescopic cylinder 130 is hinged to the first beams 111, and the other end of the telescopic cylinder 130 is hinged to the second beams 121.

Further, the cross-sections of the first beam 111 and the second beam 121 are rectangular or circular.

In this embodiment, the cross-sections of the first beam 111 and the second beam 121 are rectangular.

In the prior art, in order to improve the capability of the main arm mast to bear bending moment, it is necessary to increase the material thickness and strength of the main arm mast, change the sectional area of the main arm mast, and the like. These measures result in a considerable increase in the weight and cost of the mast of the primary jib. Meanwhile, the increase of the length and the weight of the mast of the main jib can cause the corresponding increase of the mechanism capacity of the jacking oil cylinder, namely the diameter and the stroke of the oil cylinder are increased. Above measure not only can greatly increased complete machine cost, simultaneously, the increase of jacking cylinder diameter can lead to originally not enough with regard to the space of crowded revolving stage of hoist in space to will increase the revolving stage, and then lead to the enlargeing of complete machine size, the surge of cost.

In this embodiment, in which the jib mast is made into a telescopic structure, as shown in fig. 7, the telescopic jib mast 100 is divided into a first support 110 and a second support 120, the first beam 111 and the second beam 121 are made into a nested form with different cross sections, and the first beam 111 and the second beam 121 are rectangular in cross section. The cross-sections of the two-stage box-shaped structures are different in size, so that the sleeving is guaranteed. For example, wherein the cross-section of the second beam 121 of the second bracket 120 has a height h₁Width w₁The cross section of the first beam 111 of the first bracket 110 has a height h₂Width w₂And then: h is₁＜h₂And w1 < w₂(ii) a Or, h₁＞h₂And w₁＞w₂。

In the present example, the first case, i.e., h1 < h2 and w1 < w2, is shown. The inside of the first cross member 111 and the second cross member 121 is extended and contracted by the telescopic cylinder 130, and the length of the telescopic jib mast 100 in the extended state is increased by d compared with the length in the contracted state, thereby increasing the length of the jib mast.

Preferably, the telescopic cylinder 130 is a hydraulic cylinder or an air cylinder.

Comparison of expansion and contraction of the telescoping mast boom 100, shown in FIG. 8The length of the telescopic jib mast 100 in the open state is greater than the length of the telescopic jib mast by d, and particularly, when the telescopic jib mast is used on a crane, as shown in fig. 10 and 11, the telescopic cylinder 130 is retracted to the minimum stroke, and the length of the jib mast is the shortest, i.e., L₁The bending moment of the main arm mast caused by the dead weight is minimum, so that the main arm mast is smoothly pulled up against the bending moment generated by the dead weight without causing damage.

When the main arm mast is pulled up to the vertical position through the jacking oil cylinder, the telescopic cylinder 130 of the main arm mast is pushed out and can be pushed out to the longest stroke, and the length of the main arm mast is L'₁。

And then the jacking oil cylinder continues jacking, the mast of the main arm continues to tilt forwards, and when the mast of the main arm is separated from the jacking oil cylinder, the main arm continuously bends forwards to a required angle by using the self weight of the mast of the main arm through the rope unwinding of the luffing winch of the main arm. In this case, the length of the mast is L'₁Compared with the original length L₁Pulling force F 'required to lift boom 200'₁Relatively small, axial force to boom 200, i.e. F'₁Horizontal component F'_1xAnd also smaller, to achieve a longer main arm length to cock.

In fact, considering that the telescopic main arm mast 100 forms an angle with the vertical direction when the boom 200 is cocked, as shown in fig. 12, the main arm mast does not need to be cocked to 90 °, i.e., the vertical position, and can perform the telescopic action within the range of 90 ° ± or less. Typically we choose 30 or less, i.e. the telescopic jib mast 100 can be made to extend or retract in length within 60-120 or less from horizontal.

It should be noted that the telescopic jib mast 100 can also be selected to be extended or retracted when the telescopic jib mast 100 is at 90 ° to the horizontal plane, i.e., when the telescopic jib mast 100 is in a vertical state.

The crane provided by the embodiment comprises a rotary table 400, a jacking mechanism 500, a luffing mechanism, a pulling plate 300, an arm support 200 and a telescopic main arm mast 100; one end of the telescopic main arm mast 100 is rotatably connected with the rotary table 400; one end of the jacking mechanism 500 is connected with the rotary table 400, and the other end is connected with the telescopic main arm mast 100; one end of the arm support 200 is rotatably connected with the rotary table 400, and the other end of the arm support 200 is connected with one end of the telescopic main arm mast 100, which is far away from the rotary table 400, through the pulling plate 300; the luffing mechanism is connected to one end of the telescopic main jib mast 100, which is far away from the rotary table 400, and is used for driving the telescopic main jib mast 100 to rotate.

The telescopic main jib mast 100 in a contracted state is cocked through the jacking mechanism 500, then the telescopic main jib mast 100 is unfolded, the boom 200 and the telescopic main jib mast 100 are connected through the pulling plate 300, and the telescopic main jib mast 100 is driven to rotate by the luffing mechanism, so that the cocking of the boom 200 is realized, the bending deformation and the failure of the main jib mast are avoided, meanwhile, the stress of the boom 200 and the pulling plate 300 can be effectively improved due to the increase of the length of the telescopic main jib mast 100, and the stability of the crane is improved.

As shown in fig. 10, in this embodiment, the luffing mechanism includes a luffing winch 610 and a turntable pulley block 630 disposed on the turntable 400, a main arm mast pulley block 620 disposed at an end of the telescopic main arm mast 100 away from the turntable 400, and a luffing wire rope 640 sequentially connecting the turntable pulley block 630, the main arm mast pulley block 620 and the luffing winch 610, and the luffing wire rope 640 is wound by the luffing winch 610 to realize rotation of the telescopic main arm mast 100 relative to the turntable 400, thereby lifting the boom 200.

As shown in fig. 1, 4 to 6, which are schematic diagrams of a crane for lifting a boom 200 without a super lift device, wherein the weight of the boom 200 is G₁At a distance D from the center of rotation₀In the process of cocking the boom 200, the main arm mast is connected to the boom 200 through the pulling plate 300, and the pulling force of the pulling plate 300 is F₁. Tensile force F₁At an angle of β with the horizontal₁。

As shown in fig. 4, during the lifting process of the arm support 200, the forward tilting moment M is mainly generated by the self weight of the arm support 200₁＝G₁×D₀. Obviously, the raising of the boom 200 of a greater length will result in G₁And D₀Are all large, thereby leading to a forward tilting moment M₁The larger the forward-tilting moment, the larger the forward-tilting moment will affect the stability of the whole crane, so the stability of the whole crane limits the longest arm length which can be pulled up under the condition that the crane does not have the super-lift device.

As shown in fig. 4, 5 and 6, wherein F₁Can be decomposed into a component F in the horizontal direction_1xAnd a component F in the vertical direction_1yWherein, the moment is obtained by the connecting hinge point of the arm support 200 and the turntable 400, and G is known₁And F₁Has a relationship of G₁×D₀＝F_1y×D₁I.e. F_1y＝G₁×D₀/D₁. When the boom 200 is long, G₁And D₀Are all larger, resulting in a need for larger F_1yIf the tensile force F is₁At an angle β from horizontal₁Not changing, i.e. requiring a larger F₁。

Meanwhile, as can be seen from fig. 1, the steel wire rope of the main arm luffing winch bypasses the turntable pulley block and the main arm mast pulley block, and in the process of pulling up the boom 20, the main arm luffing winch drives the luffing steel wire rope to pull up the main arm mast backwards, and the main arm mast pulls up the boom 20 through the pulling plate 30 with a pulling force of F₁. The mechanical capability of the luffing mechanism consisting of the luffing winch of the main arm, the luffing wire rope, the rotary table pulley block and the mast pulley block of the main arm determines F₁The size of (2). I.e. the mechanical capacity of the luffing mechanism determines the length of the longest main arm that can be cocked. The mechanism capacity of the mechanism can be realized by increasing the speed ratio of the main arm variable-amplitude winch speed reducer, increasing the grade of the breaking force of the steel wire rope and increasing the number of pulley blocks.

However, it is practically impossible to increase F by infinity₁To increase the maximum arm length for cocking. Because F₁Horizontal component F of_1xFor the arm support, the axial force along the length direction of the arm support is used. As shown in fig. 5, the arm support is subjected to gravity to generate downward deflection when the arm support is lifted, and the arm support is in a bending state. At this time F₁Horizontal component F of_1xIf the size is too large, buckling instability of the arm support is caused, and arm lifting failure is caused. Thus, F₁Is limited by the stability of the boom, thus limiting the longest arm length that can be cocked in this case.

In fact, the effective method is to use the longer mast length of the main arm and increase the included angle between the pulling plate and the arm support, thereby improving the stress of the arm support, breaking through the limitation of the stability of the arm support and increasing the longest arm length which can be pulled up.

In this embodiment, by using the telescopic mast boom 100, when the mast is pulled from a lying-down state, the telescopic mast boom 100 is in a contracted state, so that the distance variation M caused by its own weight can be reduced₂Deformation damage at the jacking mechanism 500 is avoided.

As shown in FIGS. 13 and 14, the length of the telescopic jib mast 100 is set to L₁To L'₁Pull plate 300 force F₁At an angle β from horizontal₁Will correspondingly increase, and the increased angle is β'₁. At this time, since F₁Component F of the vertical direction_1y＝G₁×D₀/D₁Fixed value, then with β₁Increase is β'₁. As is readily apparent from FIG. 14, F₁And F₁Horizontal component F of_1xAre all reduced, and the reduced value is F'₁And F'_1xI.e. F'₁＜F₁And F'_1x＜F_1x. Wherein, F'₁＜F₁The mechanism capability of the luffing mechanism formed by the luffing winch 610, the luffing steel wire rope 640, the rotary table pulley block 630 and the main arm mast pulley block 620 can be correspondingly reduced, namely, the speed ratio of a luffing winch speed reducer does not need to be increased, the grade of the breaking force of the steel wire rope is increased, and the number of the pulley blocks is increased, so that the cost is reduced. Simultaneously, F'_1x＜F_1xThe axial force applied to the arm support 200 is reduced, the buckling safety coefficient is increased, the risk of buckling instability of the arm support 200 is reduced, and at the moment, the longer arm support 200 can be pulled up. Thus, by using a longer telescoping mast jib mast 100, a longer jib length can be cocked.

As shown in fig. 9 to 12, the telescopic jib mast 100 is in a horizontal state when being mounted on the rotating platform 400 of the crane, and if the boom 200 is to be wrenched, the telescopic jib mast 100 is wrenched first, the telescopic jib mast 100 is wrenched by the jacking cylinder connected to the rotating platform 400, and when the telescopic jib mast 100 is wrenched, the telescopic cylinder 130 is retracted to a minimum stroke, at this time, the length of the jib mast is shortest, that is, the length of the jib mast is L₁Herein, thisThe bending moment of the telescopic main arm mast 100 caused by the dead weight is minimum, so that the telescopic main arm mast 100 can be smoothly pulled up against the bending moment generated by the dead weight without causing damage.

And then the jacking oil cylinder continues to jack, the telescopic main arm mast 100 continues to tilt forwards, and when the telescopic main arm mast 100 is separated from the jacking oil cylinder, the telescopic main arm mast 100 continues to lie forwards to a required angle by the aid of the dead weight of the telescopic main arm mast 100 through rope unwinding of the main arm luffing winch. In this case, the length of the mast is L'₁Pull plate 300 force F 'required for boom raising'₁Less, axial force to boom 200, i.e. F'₁Horizontal component F'_1xAnd also smaller, to achieve a longer main arm length to cock.

In fact, considering that the telescopic main arm mast 100 forms an angle with the vertical direction when the boom 200 is cocked, as shown in fig. 12, the telescopic main arm mast 100 does not need to be cocked to 90 °, i.e., a vertical position, and can perform a telescopic action of the length of the telescopic main arm mast 100 within a range of 90 ° ± or less. Typically we choose ≦ 30 °, i.e. the jib mast can be made to extend and retract in length in the range 60 ° -120 ° or less.

In this embodiment, the crane may be a crawler crane.

The operating method of the crane provided by the embodiment comprises the following steps: driving the telescopic main arm mast 100 to a set position by using the jacking mechanism 500; when the telescopic main boom mast 100 reaches a set position, driving the telescopic main boom mast 100 to extend to a preset length by using a driving mechanism; when the telescopic main boom mast 100 extends to a preset length, the arm support 200 and one end of the telescopic main boom mast 100, which is far away from the rotary table 400, are connected through the pulling plate 300; the luffing mechanism drives the telescopic main jib mast 100 to rotate and perform the wrenching action of the arm support 200, the jacking mechanism 500 drives the telescopic main jib mast 100 to a set position and then to a preset length, and then the luffing mechanism drives the telescopic main jib mast 100 to rotate, so that the wrenching action of the arm support 200 is performed. The bending failure of the mast of the main arm is avoided, meanwhile, under the condition that the crane does not have a super-lift device, the requirement on the power of the luffing mechanism is reduced, meanwhile, the axial force of the pulling plate 300 acting on the arm support 200 is reduced, the risk of buckling instability of the arm support 200 is reduced, and therefore the capacity of pulling the longer arm support 200 is achieved.

Further, the setting position of the telescopic jib mast 100 is such that an included angle between the extending direction of the telescopic jib mast 100 and a horizontal plane satisfies: 60 to 120 degrees.

Specifically, the included angle between the telescopic main boom mast 100 and the vertical direction is ± 30 °, that is, the telescopic main boom mast 100 can be extended and retracted by using the driving mechanism when the included angle between the length direction thereof and the horizontal plane is 60 ° to 120 °.

It should be noted that the optimal telescopic position of the telescopic mast boom 100 is perpendicular to the horizontal plane, and the bending moment of the telescopic mast boom 100 due to its own weight is the smallest.

In summary, the telescopic main arm mast 100 provided by the invention comprises a plurality of stages of telescopic supports which are sequentially connected in a sliding manner; the joint of two adjacent telescopic supports is provided with actuating mechanism, and actuating mechanism's one end and one telescopic support in two adjacent telescopic supports are connected, and actuating mechanism's the other end and another telescopic support in two adjacent telescopic supports are connected, and actuating mechanism can drive the expansion and the shrink of two adjacent telescopic supports. Compared with the prior art, the telescopic main arm mast 100 provided by the invention realizes the extension and contraction of the main arm mast in the length direction through the multi-stage telescopic support and the driving mechanism which are sequentially connected in a sliding manner, realizes the turning-up of the telescopic main arm mast 100 in a contraction state, and then realizes the unfolding of the telescopic main arm mast 100 through the driving mechanism, thereby avoiding the risk that the main arm mast bears a great bending moment due to self weight in the turning-up process, so that the material of the main arm mast is invalid and damaged, and the normal use of a crane is influenced.

The crane provided by the invention comprises a rotary table 400, a jacking mechanism 500, a luffing mechanism, a pulling plate 300, an arm support 200 and a telescopic main arm mast 100; one end of the telescopic main arm mast 100 is rotatably connected with the rotary table 400, one end of the jacking mechanism 500 is connected with the rotary table 400, the other end of the boom frame 200 is rotatably connected with the telescopic main arm mast 100, the other end of the boom frame 200 is connected with one end of the telescopic main arm mast 100, which is far away from the rotary table 400, through the pulling plate 300, the luffing mechanism is connected with one end of the telescopic main arm mast 100, which is far away from the rotary table 400, and is used for driving the telescopic main arm mast 100 to rotate, the telescopic main arm mast 100 in a contracted state is pulled up through the jacking mechanism 500, then the telescopic main arm mast 100 is unfolded, the boom frame 200 is connected with the telescopic main arm mast 100 through the pulling plate 300, and the telescopic main arm mast 100 is driven to rotate by the luffing mechanism, so that the pulling up of the boom 200 is realized, the bending deformation, and the stress of the arm support 200 and the pull plate 300 can be effectively improved, and the stability of the crane is improved.

The invention provides an operation method of a crane, which comprises the following steps: driving the telescopic main arm mast 100 to a set position by using the jacking mechanism 500; when the telescopic main boom mast 100 reaches a set position, driving the telescopic main boom mast 100 to extend to a preset length by using a driving mechanism; when the telescopic main boom mast 100 extends to a preset length, the arm support 200 and one end of the telescopic main boom mast 100, which is far away from the rotary table 400, are connected through the pulling plate 300; the telescopic main arm mast 100 is driven to rotate by the luffing mechanism and the turning-up action of the arm support 200 is executed. The telescopic main jib mast 100 is driven to a preset length after being driven to a set position by the jacking mechanism 500, and then the telescopic main jib mast 100 is driven to rotate by the luffing mechanism, so that the arm support 200 is lifted. The bending failure of the mast of the main arm is avoided, meanwhile, under the condition that the crane does not have a super-lift device, the requirement on the power of the luffing mechanism is reduced, meanwhile, the axial force of the pulling plate 300 acting on the arm support 200 is reduced, the risk of buckling instability of the arm support 200 is reduced, and therefore the capacity of pulling the longer arm support 200 is achieved.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.