Safety protection devices for preventing tower crane collapse and tower cranes

Abstract

This invention relates to a safety protection device for preventing tower crane collapse and a tower crane including the safety protection device. The tower crane includes at least a jib and a top connection of the tower body. The safety protection device includes a damping connector and a partially enclosed lug assembly. The damping connector is fixed at both ends to the jib and the top connection of the tower body, respectively. The lug assembly has at least an upper lug, a pair of lower lugs, and a hinge pin. The upper lug is fixed to the jib, and the lower lugs are fixed to the top connection of the tower body, with the lower lugs located on opposite sides of the upper lugs. The hinge pin extends through the upper and lower lugs and is pivotable and vertically displaced within the lower lugs by a certain distance. The lug assembly cooperates with the damping connector to allow the jib to tilt upwards relative to the top connection of the tower body and then return to its normal operating position. The safety protection device allows for moderate jib tilting, prevents excessive jib tilting or disengagement, and reduces shear force on the pin to prevent tower crane collapse.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tower cranes, and in particular to a safety protection device for preventing a tower crane from toppling over and to a tower crane comprising the safety protection device. BACKGROUND

[0002] In practice, due to the heavy counterweight of the super-large tower crane, the tower crane bears a large back-bending moment, and the hoisting load is heavy. When the super-large tower crane faces a sudden unloading working condition, the jib will be subjected to a huge reaction force brought by unloading. At this time, the reaction force on the jib and the counterweight pressure on the balance arm are superimposed, and the tower crane is at risk of toppling over under the double action force.

[0003] Specifically, referring to Figure 1 , the existing tower crane mainly comprises a counterweight 20, a balance arm 22, an intermediate arm 23, a jib 24, a tower body 26, and a tower body top connecting piece 25. The counterweight 20 is installed at the tail of the balance arm 22, and a falling device can be used to make the counterweight fall off. The intermediate arm 23 is connected with the balance arm 22, the jib 24, and the tower body top connecting piece 25, respectively. The tower body top connecting piece 25 is connected with the tower body 26 at the lower part. The intermediate arm 23 and the tower body top connecting piece 25 are hinged through four completely closed ear plate assemblies so as to be pivotable about the hinge pin 10. In this specification, the length direction of the arm assembly of the tower crane will be referred to as the longitudinal direction, wherein the side facing the jib 24 will be referred to as the longitudinal front side, and the side facing the balance arm 22 will be referred to as the longitudinal rear side. The direction perpendicular to the length direction of the arm assembly of the tower crane will be referred to as the transverse direction. Thus, the above-mentioned four completely closed ear plate assemblies include two ear plate assemblies installed in the front-rear direction (i.e., the left-right direction as shown) and two ear plate assemblies correspondingly installed in the transverse direction. Each completely closed ear plate assembly comprises an upper ear plate 28 having a central hole, two lower ear plates 27 located on opposite sides of the upper ear plate and having central holes, and a hinge pin 10 inserted through the central holes 30 of the upper ear plate and the lower ear plates. The upper ear plate 28 is fixed to the bottom of the lower chord of the intermediate arm 23, and the lower ear plates 27 are fixed to the upper part of the upper chord of the tower body top connecting piece 25. Figure 1

[0004] ​When the super-large tower crane faces the sudden unloading working condition or the anchor hoisting working condition, the jib or the balance arm has a tendency to tilt upward, and when the bending moment borne by the tower exceeds the limit value that the tower can bear, the tower crane has the risk of tower fracture and tower collapse. In the two working conditions, since the pin shaft is in the completely closed center hole 30 of the lower ear plate 27, the four orientation degrees of freedom of the pin shaft are limited, and when the jib or the balance arm tilts upward, the corresponding pin shaft 10 is subjected to a great shearing force due to the above-mentioned limitation and is prone to fracture, thereby causing the risk of tower fracture and tower collapse. In order to prevent the tower from fracturing and collapsing, the diameter of the pin shaft can be increased. However, due to the structure of the double lower ear plate to the single upper ear plate, the diameter of the pin shaft is limited due to the limitation of the local space. Moreover, since the pin shaft is subjected to a large shearing force, the structural safety factor is low. Therefore, the hinge provided by the completely closed ear plate assembly is difficult to resist the risk of tower collapse of the tower crane.

[0005] Therefore, a safety protection device for preventing the tower crane from collapsing is needed to reduce the risk of tower fracture and collapse as much as possible. SUMMARY

[0006] In order to solve the above technical problems, the present application provides the following concept: by means of the cooperation of the damping connector, a non-completely closed ear plate assembly is used to reduce the limitation of the four orientation degrees of freedom of the pin shaft, to at least solve the following technical problems: 1) how to allow the arm frame to tilt moderately; 2) prevent the arm frame from tilting excessively or the arm frame from falling out, and / or 3) reduce the shearing force borne by the pin shaft.

[0007] The present application provides a safety protection device for preventing the tower crane from collapsing, the tower crane at least comprising an intermediate arm and a tower top connecting piece, the safety protection device comprising: a damping connector fixed to the intermediate arm and the tower top connecting piece at both ends, respectively; and a non-completely closed ear plate assembly having at least an upper ear plate, a pair of lower ear plates and a hinge pin shaft, the upper ear plate being fixed to the intermediate arm, the lower ear plates being fixed to the tower top connecting piece, the lower ear plates being located on opposite sides of the upper ear plate, the hinge pin shaft extending through the upper ear plate and the lower ear plates and being able to pivot within the lower ear plates and displace up and down by a distance. The ear plate assembly cooperates with the damping connector, so that the intermediate arm can tilt upward relative to the tower top connecting piece and then return to the normal working state. Thus, the cooperation of the damping connector and the non-completely closed ear plate assembly allows the arm frame to tilt moderately.

[0008] In one example, the ear plate assembly further comprises at least one locking pin shaft, the upper ear plate of the ear plate assembly has an upper ear plate center hole and an upper ear plate locking hole, each lower ear plate of the ear plate assembly has a lower ear plate locking hole, the number of upper ear plate locking holes and lower ear plate locking holes is equal to the number of locking pin shafts, and the locking pin shafts respectively extend through the corresponding upper ear plate locking holes and lower ear plate locking holes. The arrangement of the locking pin shafts ensures the stability and safety of the boom when the tower crane is in the installation or experimental working condition.

[0009] In one example, the ear plate assembly is a semi-hinge slot ear plate assembly, each lower ear plate of the semi-hinge slot ear plate assembly has a semi-hinge slot with an open top, the semi-hinge slot comprises a slot arc portion and a slot extension portion extending upward from the slot arc portion, the hinge pin shaft extends through the upper ear plate center hole, is held within the slot arc portion of the two lower ear plates, and is capable of being displaced up and down within the slot extension portion. Thus, the semi-hinge slot ear plate assembly allows the hinge pin shaft to pivot and allows the hinge pin shaft to be displaced within the slot, allowing the tower crane boom to be moderately overturned.

[0010] In one example, the diameter of the center hole of the upper ear plate and the diameter of the slot arc portion of the lower ear plate are slightly larger than the diameter of the hinge pin shaft, and / or the slot extension portion is an outwardly arcuately extending slot extension portion, and the outwardly arcuately extending arc is suitable for the displacement of the hinge pin shaft within the slot extension portion when the intermediate arm rotates around the corresponding fulcrum. Thus, the hinge pin shaft is allowed to freely pivot and the hinge pin shaft is allowed to smoothly displace within the slot.

[0011] In one example, the ear plate assembly is an arc slot ear plate assembly, the arc slot ear plate assembly has two upper ear plates; each lower ear plate has a long arc-shaped hole, and the hinge pin shaft extends through the center holes of the two upper ear plates and the long arc-shaped holes of the two lower ear plates to allow the hinge pin shaft to pivot and allow the hinge pin shaft to be displaced up and down within the long arc-shaped hole. The semi-hinge slot ear plate assembly allows the hinge pin shaft to pivot and allows the hinge pin shaft to have a certain range of displacement within the slot, preventing the tower crane boom from being overturned too much.

[0012] In one example, the arc slot ear plate assembly further has an upper semi-hinge slot plate and a lower semi-hinge slot plate, the upper semi-hinge slot plate is arranged between the two upper ear plates and is fixed to the intermediate arm, and the lower semi-hinge slot plate is arranged between the two lower ear plates and is fixed to the top connector of the tower body. When installed, the lower semi-hinge slot plate is in vertical alignment with the upper semi-hinge slot plate, and there is a gap between the lower semi-hinge slot plate and the upper semi-hinge slot plate. Thus, the lower semi-hinge slot plate and the upper semi-hinge slot plate only exert a pressing force on the hinge pin shaft without exerting a shearing force, thereby improving the safety factor of the hinge pin shaft while reducing the size of the hinge pin shaft and preventing the hinge pin shaft from breaking prematurely.

[0013] In one example, the half-hinge slots of the lower half-hinge plate and the upper half-hinge plate are circular-arc half-hinge slots each having an arc less than 180 degrees, and the diameters of the two circular-arc half-hinge slots are equal to the diameter of the hinge pin, so that the hinge pin is in a hole-axle clearance fit with the hinge pin. Thus, this arrangement allows the hinge pin to pivot and reduces the shear force on the hinge pin.

[0014] In one example, the arc of the long-arc hole is adapted to the displacement of the hinge pin within the long-arc hole when the intermediate arm rotates about the corresponding fulcrum, and / or the length of the long-arc hole defines the maximum range of travel of the hinge pin within the long-arc hole. Thus, the tower crane jib is ensured to have a certain anti-overturning capability.

[0015] In one example, the arc of the long-arc hole is adapted to the arm jib rotation trajectory along which the intermediate arm rotates about the corresponding fulcrum. Thus, the arm jib is prevented from falling sideways.

[0016] In one example, the diameter of the central hole of the upper lug plate and the diameter of the long-arc hole of the lower lug plate are each slightly larger than the diameter of the hinge pin. Thus, the hinge pin is allowed to freely pivot and smoothly displace within the recess.

[0017] In one example, the tower further comprises a balance arm, an intermediate arm, a hoisting arm, and a movable counterweight, which is mounted on the superstructure of the tower crane and is movable between the balance arm, the intermediate arm, and the hoisting arm. Thus, the balance of the tower crane jib is facilitated to be adjusted.

[0018] The present application also provides a tower crane comprising the aforementioned safety protection device, which is mounted between the intermediate arm of the tower crane and the top connection of the tower body. The intermediate arm of the tower crane thus configured and consequently the jib can be moderately overturned. The tower crane further prevents the intermediate arm and consequently the jib from being over-turned or the jib from falling out. The tower crane also reduces the shear force on the hinge pin. BRIEF DESCRIPTION OF DRAWINGS

[0019] A more complete understanding of the present application, and the attendant advantages thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

[0020] Figure 1 The structure of a tower crane of the prior art is schematically shown;

[0021] Figure 2A A tower crane comprising a safety protection device according to the first embodiment of the present application is schematically shown; Figure 2B A tower crane comprising a safety protection device according to the second embodiment of the present application is schematically shown; Figure 2A A partial perspective view of the half-hinge slot lug assembly of the safety protection device is shown; Figure 2C A partial perspective view of the half-hinge slot lug assembly of the safety protection device is shown; Figure 2ALayout of the upper and lower ear plates of the semi-hinged slot ear assembly of the safety guard shown.

[0022] Figure 3A Schematic front view of a safety guard according to a second embodiment of the application; Figure 3B Schematic side view of a safety guard according to a second embodiment of the application;

[0023] Figure 4A and Figure 4B schematically show, respectively, Figure 3A Schematic front and side views of the upper part of the arc slot ear assembly of the safety guard shown;

[0024] Figure 5A and Figure 5B schematically show, respectively, Figure 3A Schematic front and side views of the lower part of the arc slot ear assembly of the safety guard shown;

[0025] Figures 6A-6C show, respectively, the assembly of the parts of the arc slot ear assembly of the safety guard shown; Figure 3A show, respectively, the assembly of the parts of the arc slot ear assembly of the safety guard shown;

[0026] Figure 7 illustrate Figure 3A Layout of the upper and lower semi-hinged slot plates of the arc slot ear assembly of the safety guard shown;

[0027] Figures 8A-8C show, respectively, a structural schematic of the lower ear plate of a prior art ear assembly, the lower ear plate of a semi-hinged slot ear assembly according to a first embodiment of the application, and the lower ear plate of an arc slot ear assembly according to a second embodiment of the application.

[0028] Figure 9 show a schematic of the movement of the boom in the event of a sudden loss of load of the tower, in the event of failure of the damping connector, among other special cases;

[0029] Figure 10 show a schematic of the movement of the boom in the event of a sudden loss of load of the tower, in the event of failure of the damping connector, among other special cases; and

[0030] Figure 11 show a schematic of the movement of the boom in the event of a sudden loss of load of the tower, in the event of failure of the damping connector, among other special cases; and DETAILED DESCRIPTION

[0031] The inventive concept according to the application and specific embodiments thereof will now be described with reference to the accompanying drawings, in which, in the various drawings, like reference numerals refer to corresponding or identical elements.

[0032] It is to be understood that the phraseology or terminology herein is for descriptive purposes only and not limiting. The terms "comprising", "having" and "including" are not exclusive and are used in the inclusive sense (i.e., to mean "including but not limited to"). The terms "coupled" and "connected," along with derivatives thereof, are intended to mean any connection, coupling, or relation between entities, direct or indirect, and can encompass a functional coupling in which the entities do not contact each other but are functionally related.

[0033] When the tower crane is working normally, the hinge pin shaft resting in the hinge hole can be under pressure; when the tower crane suddenly loses load or the anchor is lifted, the hinge pin shaft will change from the state of being under pressure to being under tension. In the design of super-large tower cranes, in order to prevent the tower crane from overturning and falling in the sudden load loss and anchor lifting conditions, by allowing the hinge pin shaft to have a certain amount of upward and downward displacement to release the tensioned hinge pin shaft, the tower crane can be prevented from bearing excessive bending moment and causing danger.

[0034] To this end, the present application provides a safety protection device for preventing tower crane from falling. The safety protection device mainly comprises a damping connector and a non-fully closed ear plate assembly fixed to the middle arm and the tower body top connector of the tower crane, respectively. As used herein, the term "non-fully closed ear plate assembly" refers to an ear plate assembly that allows the hinge pin shaft to both pivot in the lower ear plate and to displace upward and downward. The damping connector cooperates with the non-fully closed ear plate assembly to allow the boom to moderately overturn and then return to the normal operating state.

[0035] Figure 2A A safety protection device for preventing tower crane from falling according to the first embodiment of the present application is schematically shown. According to the present application, the tower crane can at least include a counterweight 20, a balance arm 22, a middle arm 23, a lifting arm 24, a movable counterweight 21, a tower body 26, and a tower body top connector 25. The tower body top connector 25 is a component to be connected with the middle arm 23, which can be a special knot or an upper support, etc. In the present embodiment, the tower body top connector 25 is taken as an example to be shown as a special knot. Figure 2A The counterweight 20 is removably (e.g., by a shedding device) connected near the free end of the balance arm 22 and can be shed from the balance arm 22 in the event of, for example, a sudden load loss. The movable counterweight 21 can be installed on the upper structure of the tower crane and can reciprocate between the balance arm 22, the middle arm 23, and the lifting arm 24 to facilitate the adjustment of the balance of the tower crane boom. According to the lifting load on the lifting arm 24 and the distance from the vertical center axis of the tower body 26, the movable counterweight 21 can be moved to the appropriate position in real time to balance the bending moment on both sides of the tower body with the counterweight 20.

[0036] Similar to the prior art tower crane, the non-fully closed ear plate assembly also has four, two of which are respectively installed at the top front end or the top rear end of the tower body top connector 25 in the front-rear direction (see FIG. 1). The other two are respectively installed at the top front end or the top rear end of the middle arm 23 in the front-rear direction (see FIG. 2). Figure 3A), while the other two are laterally spaced apart from the first two (see Figure 3B ), and are also correspondingly installed at the top front end or the top rear end of the tower top connector 25. Similarly, there are also four correspondingly arranged damping connectors.

[0037] Figure 2A The safety protection device for preventing tower collapse of the first embodiment of the present application shown mainly comprises: damping connectors 12 connected to the middle arm 23 (i.e., connected to the bottom of the lower chord of the middle arm 23) and the tower top connector 25 (i.e., connected to the upper part of the lower chord of the tower top connector 25) at both ends, respectively; and a non-fully closed ear plate assembly for hinging the middle arm 23 with the tower top connector 25. The non-fully closed ear plate assembly is configured to allow the middle arm 23 and the entire arm assembly to be pivoted around the top rear end or the top front end (see Figures 9-10 , fulcrum 1 and fulcrum 2) of the tower top connector 25, and to be moved upward a distance relative to the top rear end or the top front end of the tower top connector 25, thereby allowing the lifting arm 24 or the counterweight arm 22 to be moderately tilted upward.

[0038] In the initial position (the middle arm is in the regular operating state), the middle arm 23 abuts against the tower top connector 25 at both the fulcrum 1 and the fulcrum 2 (see Figures 9-10 ). When the middle arm 23 moves away from the tower top connector 25 from the initial position, the damping connectors 12 provide a pulling force to the middle arm 23, causing it to be slowly tilted upward; when the middle arm 23 moves toward the tower top connector 25, the damping connectors 61 provide a resistance to the middle arm 23, causing it to be slowly returned to the initial position. That is, no matter whether the middle arm 23 is tilted upward around the fulcrum 1 or the fulcrum 2, the damping connectors 12 can slowly return the middle arm 23 to the initial position, thereby returning the moderate upward tilt of the lifting arm 24 or the counterweight arm 22 to the initial position. The damping connectors 12 can be friction dampers or hydraulic dampers.

[0039] Figure 2A The non-fully closed ear plate assembly shown is a half-hinged groove type ear plate assembly, and the specific structure thereof will be described by taking the half-hinged groove type ear plate assembly circled in the figure as an example. Referring to Figures 2A-2C , each half-hinged groove type ear plate assembly comprises: an upper ear plate 17 having an upper ear plate center hole and two upper ear plate locking holes; two half-hinged groove type lower ear plates 16 located at opposite sides of the upper ear plate; a hinge pin 10; and a locking pin 11. The half-hinged groove type lower ear plate 16 comprises a top-opened groove 31 and two lower ear plate locking holes below the groove. The number of the locking pins 11 is equal to the number of the upper ear plate locking holes and the lower ear plate locking holes, and can be at least one. Figure 2AA hinge pin 10 and two locking pins 11 are shown. The groove 31 may be a generally U-shaped groove. The groove 31 may include a lower arcuate portion and an extension extending upward from the arcuate portion. In one example, the arcuate portion has an arcuate radius no greater than 180 degrees, for example, 130-180 degrees, to hold the hinge pin 10 and allow it to pivot within the arcuate portion. The extension provides a certain amount of displacement travel for the hinge pin 10. The extension may be a vertical extension. Preferably, the extension is a slightly outwardly arcuate extension. The arcuate radius of the extension extending along the arcuate radius can be determined by... Figure 9 The radius is determined by using either fulcrum 1 or fulcrum 2 as the center, with the distance between fulcrum 1 and fulcrum 2 as the radius. The hinge pin 10 passes through the center hole of the upper ear plate 17 and is held within the arcuate portion of the groove 31 of the lower ear plate 16. The diameter of the center hole of the upper ear plate 17 and the arcuate portion of the groove 31 of the lower ear plate 16 can be equal, and both can be slightly larger than the diameter of the hinge pin 10, to allow the hinge pin 10 to pivot and to allow the hinge pin 10 to move smoothly within the groove 31. Since the hinge pin 10 is pivotally held within the arcuate portion of the groove 31 and can move up and down within the extension of the groove 31, on the one hand, the shear force of the lower ear plate 16 on the hinge pin 10 can be reduced or eliminated to prevent the hinge pin from breaking; on the other hand, in cooperation with the damping connector (which provides tension or resistance), it allows the boom to tilt moderately and then return to the normal operating state, thereby reducing the possibility of tower collapse.

[0040] When the tower crane is in installation, dismantling, or testing mode, the two locking pins 11 can be extended through the corresponding upper and lower ear plate locking holes to connect and lock the upper and lower ear plates together, i.e., the upper and lower ear plates are fixed together in a way that prevents them from pivoting or separating. The diameters of the upper and lower ear plate locking holes can be equal, and both slightly larger than the diameter of the locking pins 11, for example, by 1-2 mm.

[0041] The upper ear plate 17 is fixed (e.g., by welding or mechanical connection) to the intermediate arm 23, for example, to the bottom of the lower chord of the intermediate arm 23, and the semi-hinged lower ear plate 16 is fixed to the tower top connector 25, for example, to the upper part of the upper chord of the tower top connector 25.

[0042] Because the grooves 31 of the two lower ear plates 16 of the semi-hinged lug assembly are open at the top, the hinge pin 10 is allowed to move upward within the groove 31, thus allowing the lifting boom or counterweight boom to tilt upward as a whole. (The following is in conjunction with...) Figures 9-10 The working principle of the safety protection device according to the first embodiment of the present invention will be described.

[0043] When the tower crane is under sudden unload conditions, the jib bears an impact load, and an unbalanced load appears at the front and rear of the tower crane, exceeding the tension provided by the damping connector. The hinge pin 10 at fulcrum 2 will shift upwards within the groove 31 (see reference). Figure 9 When the crane boom tilts upwards from its initial position, using fulcrum 1 as the fulcrum, the counterweight detachment device is triggered, causing the counterweight 20 at the tail of the counterweight boom to detach, thereby reducing the backward tilting moment of the upper part of the tower crane. After the counterweight detaches, the forward tilting moment of the tower crane is greater than the backward tilting moment, and the crane boom 24 will slowly fall back to its initial position under the resistance of the damping connector 12, thus ensuring that the tower crane does not collapse under the condition of sudden unload.

[0044] When the tower crane is in anchoring mode, the lifting force on the boom will continuously increase, and the bending moment on the boom side will continuously increase. When the forward bending moment on the boom side is greater than the backward bending moment on the counterweight boom side and the bending moment provided by the damping connector, the hinge pin 10 at fulcrum 1 will displace upward within the groove 31 (refer to...). Figure 10 When the counterweight boom is fulcrum 2, it will tilt upwards from its initial position. At this time, the tower crane stops working and the hook is unloaded. The counterweight boom slowly falls under the resistance of the damping connector 12, which effectively improves the safety of the tower crane anchor and ensures that the tower crane will not collapse under the anchor condition.

[0045] Therefore, by allowing the hinge pin 10 to move up and down within the groove 31, the lifting arm or counterweight arm is allowed to tilt upwards, thus achieving the tower crane's anti-tipping mechanism.

[0046] However, since the groove 31 of the semi-hinged lower ear plate is open at the top, it lacks limitations on the upward tilt of the boom or counterweight boom and the downward tilt of the boom. During the upward tilt of the boom or counterweight boom, if special circumstances such as damping connector failure occur, the intermediate boom and therefore the boom may overturn under the action of inertial force. During the downward tilt of the intermediate boom, if the downward force of the intermediate boom is less than the supporting force of the damping connector, there is a risk that when the damping connector connection point is used as the fulcrum, the hinge pin on one side may not have returned to the initial point, while the hinge pin on the other side may have disengaged from the hinge position, thus causing the intermediate boom and therefore the boom to detach from the lateral side as a whole. Overturning or detachment of the intermediate boom and therefore the boom will cause the upper boom to fall as a whole. To this end, the present invention also provides further improvements to the safety protection device of the first embodiment to prevent the intermediate boom and therefore the boom from overturning or detaching.

[0047] like Figure 3A As shown, the safety protection device for preventing tower crane collapse according to the second embodiment of the present invention provides further protection against the aforementioned special circumstances. Components identical to those in the first embodiment are indicated by the same reference numerals in the second embodiment. Structures or layouts identical to those in the first embodiment in the second embodiment will not be described in detail.

[0048] The safety shield according to the second embodiment of the present application comprises four non-fully enclosed lug assemblies in the form of arcuate lug assemblies for articulating the intermediate boom 23 with the tower top connector 25 in addition to the four dampening connectors 12.

[0049] Referring to Figures 4A-6C Each arcuate lug assembly comprises two upper lugs 7 having a central hole and two upper lug locking holes, two lower lugs 6 in the form of an arcuate slot on opposite sides of the upper lugs, an articulation pin 10, and two locking pins 11. The lower lugs 6 in the form of an arcuate slot comprise an upper long arcuate hole 32 and two lower lug locking holes below the long arcuate hole. Referring to Figure 3A and Figures 9-11 The arc of the long arcuate hole 32 is defined by a circle having the fulcrum 1 or the fulcrum 2 as a center and the distance between the fulcrum 1 and the fulcrum 2 as a radius. The length of the long arcuate hole 32 defines the maximum travel of the articulation pin 10 within it, thereby defining the degree of over-tilting prevention of the tower boom. The articulation pin 10 passes through the central holes of a pair of upper lugs 28 and is retained within the long arcuate hole 32 of the lower lugs 6. The articulation pin 10 is displaceable up and down within the long arcuate hole 32 of the lower lugs 6. The central holes of the upper lugs 7 can be equal in diameter to the long arcuate hole 32 of the lower lugs 6, both being slightly larger than the diameter of the articulation pin 10, for example, 1-2 mm larger.

[0050] Similar to the first embodiment, the upper lug locking holes and the lower lug locking holes can be equal in diameter, both being slightly larger than the diameter of the locking pin 11, for example, 1-2 mm larger. The locking pin 10 extends through a respective pair of upper lug locking holes and a pair of lower lug locking holes to non-pivotably and non-separably secure the upper lugs and the lower lugs to each other for use when the tower is in the erecting or dismantling or testing condition. The upper lugs 7 are secured (e.g., by welding, mechanical connection, etc.) to the intermediate boom 23, namely to the bottom of the lower chord of the intermediate boom 23, and the lower lugs 6 in the form of an arcuate slot are secured (e.g., by welding, mechanical connection, etc.) to the tower top connector 25, namely to the upper portion of the upper chord of the tower top connector 25.

[0051] In addition, referring to Figure 4BAn upper half hinge slot plate 9 is fixed to the middle arm 23 (i.e. to the bottom of the lower chord of the middle arm 23), and a lower half hinge slot plate 8 is fixed to the tower top connector 25 (i.e. to the upper part of the upper chord of the tower top connector 25) between the two lower ear plates 6. The half hinge slots of the lower half hinge slot plate 8 and the upper half hinge slot plate 9 are in the shape of a partial circular arc with an arc angle slightly less than 180 degrees. The diameter of the half hinge slots of the lower half hinge slot plate 8 and the upper half hinge slot plate 9 is equal to the diameter of the hinge pin 10. When installed, the lower half hinge slot plate 8 and the upper half hinge slot plate 9 are in vertical alignment with a gap L (see Fig. 4) between them, so that they can form a hole- shaft gap fit with the hinge pin 10, allowing the hinge pin 10 to pivot therein. Because of the gap L, the lower half hinge slot plate 8 and the upper half hinge slot plate 9 only apply a squeezing force to the hinge pin 10 without applying a shearing force, thereby improving the safety factor of the hinge pin while reducing the size of the hinge pin. Thus, the arrangement of the lower half hinge slot plate 8 and the upper half hinge slot plate 9 can prevent the hinge pin 10 from breaking prematurely, thereby preventing the tower from collapsing. Figure 7

[0052] Figures 6A-6C The assembly state of the arc slot ear plate assembly is described in different views. A pair of upper ear plates 7 is inserted into a pair of lower ear plates 6, respectively, so that the lower half hinge slot plate 8 and the upper half hinge slot plate 9 are in vertical alignment, and then the hinge pin 10 is extended through the long arc-shaped holes 32 of the two lower ear plates and the center holes of the two upper ear plates.

[0053] Figures 8A-8C ​​The mutual contrast between the round hole 30 of the lower ear plate of the prior art ear plate assembly, the recess 31 of the lower ear plate of the semi-hinge slot ear plate assembly according to the first embodiment of the present application and the long arc slot 32 of the lower ear plate of the arc slot ear plate assembly according to the second embodiment of the present application is shown respectively. The round hole 30 of the lower ear plate of the fully enclosed ear plate assembly restricts the 4 orientation degrees of freedom of the hinge pin, not only hinders the upward tilting of the jib or counter jib, but also is prone to breakage due to the shear force applied by the upper ear plate 28 and the double lower ear plate 27. The recess 31 of the lower ear plate of the semi-hinge slot ear plate assembly allows the upward and downward displacement of the hinge pin 10 within the recess 31, allows the jib or counter jib to tilt moderately and then return to the normal operating state, thereby preventing the tower from falling. Moreover, the top of the recess 31 is open, so that the double lower ear plate 16 only applies extrusion force to the hinge pin 10 without applying shear force, so that the hinge pin 10 is not prone to premature breakage, thereby also preventing the tower from falling. The long arc slot 32 of the lower ear plate of the arc slot ear plate assembly allows the hinge pin 10 to be displaced within the long arc slot 32 by a set stroke, allows the amount of tilting of the jib or counter jib to be controlled within a certain range, thereby preventing the intermediate arm and thus the boom from over-tilting and / or falling out. As shown above, the reduced shear of the arc slot ear plate assembly on the hinge pin 10 is achieved through the upper and lower semi-hinge slot plates.

[0054] The safety protection device including the arc slot ear plate assembly will be described below with reference to Figures 9-11 how to prevent the intermediate arm and thus the boom from over-tilting and / or falling out.

[0055] With reference to Figure 9 , when the tower suddenly loses load, if special conditions such as failure of the damping connector occur, the intermediate arm will pivot around the fulcrum 1, and the tail counterweight will fall off, the boom will continue to pivot under the action of inertial force, the hinge pin 10 at the fulcrum 2 will be lifted from the arc slot lower ear plate 6 and displaced along an arc trajectory (i.e., the boom rotation trajectory line shown by the dashed line), when the hinge pin 10 is lifted to the maximum stroke of the long arc slot 32 of the arc slot lower ear plate 6, the intermediate arm will be locked by the upper ear plate 7 at the fulcrum 2, the arc slot lower ear plate 6 and the hinge pin 10, thereby preventing the intermediate arm and thus the boom from over-tilting.

[0056] With reference to Figure 10 , when the tower is anchoring, if the bending moment borne by the tower exceeds the limit value that the tower can bear and special conditions such as failure of the damping connector occur, the boom will pivot around the fulcrum 2, the hinge pin 10 at the fulcrum 1 will be lifted from the arc slot lower ear plate 6 and displaced along an arc trajectory (i.e., the boom rotation trajectory line), when the hinge pin 10 is lifted to the maximum stroke of the long arc slot 32 of the arc slot lower ear plate 6, the intermediate arm will be locked by the upper ear plate 7 at the fulcrum 1, the arc slot lower ear plate 6 and the hinge pin 10, thereby preventing the intermediate arm and thus the boom from over-tilting.

[0057] Referring to Figure 10 When the boom is falling back, if the back-falling force of the middle boom is less than the resistance of the damping connector 12, the middle boom will rotate around the fulcrum 3, at which time the rotation track of the middle boom is indicated by the small dashed circle in Figure 10 When the middle boom rotates around the fulcrum 3, because the rotation radius around the fulcrum 3 is inconsistent with the radius of the long arc-shaped hole of the arc-slot lower ear plate 6, that is, the track of the two only coincides at the fulcrum 1, which will achieve angular self-locking, that is, at the fulcrum 1, the hinge pin 10 will be clamped by the long arc-shaped hole 32 of the arc-slot lower ear plate 6, thereby preventing the hinge pin 10 from being pulled out upward. Since the hinge pin at the fulcrum 2 has not fallen back to the initial point, and the hinge pin 10 at the fulcrum 1 is lifted and separated from the support of the arc-slot lower ear plate 6, the situation that the middle boom and thus the whole boom falls out laterally can occur. Thus, the arrangement of the long arc-shaped hole of the arc-slot lower ear plate 6 prevents the boom from falling out laterally.

[0058] To this end, the arc-slot ear plate assembly can be used to prevent the tower crane boom from over-tilting and falling out and / or the hinge pin from being broken prematurely.

[0059] The present application also provides a tower crane comprising the safety protection device as described above, which is installed between the middle boom and the top connector of the tower body of the tower crane. The safety protection device can comprise a semi-hinge-slot ear plate assembly or an arc-slot ear plate assembly, so that the tower crane thus configured allows the boom to be moderately tilted. The tower crane further prevents the boom from over-tilting or falling out by using the arc-slot ear plate assembly. The tower crane thus configured can also reduce the shear force on the hinge pin.

[0060] As those skilled in the art will understand, the foregoing detailed description has been made only by way of illustration and example, and the present application is not limited only to the above-described embodiments, but can have many variations within the scope of the inventive concept defined by the following claims. Within the scope of the inventive concept, the features of one embodiment can be used in combination with the features of another embodiment or other embodiments.

Claims

1. A safety protection device for preventing tower collapse of a tower crane, the tower crane comprising at least an intermediate boom and a tower top connector, the safety protection device comprising: a damping connector fixed at both ends to the intermediate boom and the tower top connector, respectively; and a non-fully closed bracket assembly having at least an upper bracket, a pair of lower brackets and a hinge pin, the upper bracket being fixed to the intermediate boom, the lower brackets being fixed to the tower top connector, the lower brackets being located on opposite sides of the upper bracket, the hinge pin extending through the upper bracket and the lower brackets and being pivotable within the lower brackets and displaceable up and down by a distance; wherein the bracket assembly cooperates with the damping connector such that the intermediate boom is able to be tilted upward relative to the tower top connector and then return to a normal working state; wherein the upper bracket of the bracket assembly has an upper bracket central hole, each lower bracket has a long arc-shaped hole, the hinge pin extends through the upper bracket central hole and the long arc-shaped holes, the long arc-shaped holes are adapted to a boom rotation trajectory of the intermediate boom around a corresponding fulcrum, and the long arc-shaped holes are configured such that, in the event of failure of the damping connector in a tower crane anchoring condition, the hinge pin is caught by the long arc-shaped holes when a falling force of the intermediate boom is less than a resistance of the damping connector, thereby preventing the hinge pin from being pulled out upward and preventing the boom from falling sideways. The bracket assembly further comprises at least one locking pin, the upper bracket of the bracket assembly has an upper bracket locking hole, each lower bracket of the bracket assembly has a lower bracket locking hole, the number of the upper bracket locking holes and the lower bracket locking holes is equal to the number of the locking pins, and the locking pins extend through the corresponding upper bracket locking holes and lower bracket locking holes, respectively.

2. The safety guard of claim 1, wherein, The bracket assembly is an arc slot bracket assembly, the arc slot bracket assembly has two upper brackets, the hinge pin extends through the central holes of the two upper brackets and the long arc-shaped holes of the two lower brackets to allow the hinge pin to pivot and to be displaced up and down within the long arc-shaped holes.

3. The safety guard of claim 2, wherein, The arc slot bracket assembly further has an upper half hinge slot plate and a lower half hinge slot plate, the upper half hinge slot plate is arranged between the two upper brackets and is fixed to the intermediate boom, the lower half hinge slot plate is arranged between the two lower brackets and is fixed to the tower top connector, the lower half hinge slot plate is in vertical alignment with the upper half hinge slot plate and there is a gap between the lower half hinge slot plate and the upper half hinge slot plate when installed.

4. The safety guard of claim 3, wherein, The half hinge slots of the lower half hinge slot plate and the upper half hinge slot plate are circular arc half hinge slots with an arc less than 180 degrees, and the diameters of the two circular arc half hinge slots are equal to the diameter of the hinge pin, so that the hinge pin forms a hole shaft clearance fit with the hinge pin.

5. The safety guard of claim 4, wherein, The arc of the long arc-shaped hole is adapted to the displacement of the hinge pin within the long arc-shaped hole when the intermediate boom rotates around the corresponding fulcrum, and / or the length of the long arc-shaped hole defines a maximum displacement range of the hinge pin within the long arc-shaped hole.

6. The safety protection device of any one of claims 1-5, wherein, The diameters of the central holes of the upper brackets and the long arc-shaped holes of the lower brackets are slightly larger than the diameter of the hinge pin.

7. The safety protection device of any one of claims 1-5, wherein, The tower crane further comprises a balance boom, an intermediate boom, a lifting boom and a movable balance weight, the movable balance weight is installed on an upper structure of the tower crane and is movable between the balance boom, the intermediate boom and the lifting boom.

8. The safety protection device of any one of claims 1-5, wherein, ​ 9. A tower crane comprising the safety protection device according to any one of claims 1-8, installed between the middle arm and the top of the tower of the tower crane.

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