JP2018177509A - Crane and its operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crane capable of inhibiting an excessive tension from acting on a connection member.SOLUTION: A crane is provided with a crane body (1), a boom (10), a mast (20), a boom undulation rope (34), a boom undulation winch (38) for winding and unwinding of the boom undulation rope (34), a connection member (40) for connecting an upper end of the mast (20) and the crane body (1), a weight (50) for occurring a rearward moment at the mast (20), a tension detection part (62) for detecting a state of the tension occurring at the connection member (40) and a winch control part for stopping the boom undulation winch (38) when the detection value of the tension detection part (62) is greater than the threshold.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crane.

  Heretofore, as a crane having a relatively large lifting capacity, one having a lattice mast is known as seen in Patent Document 1 and the like. Specifically, this crane includes an upper swing body, a boom which can be raised and lowered relative to the upper swing body, the lattice mast, a connecting member connecting the upper end portion of the lattice mast and the upper swing body, and a bogie connecting cable. A weight carriage connected to the upper end of the lattice mast.

  The lattice mast is a member for raising and lowering the boom, and has a lattice structure. The lattice mast is attached to the upper pivot so as to be rotatable relative to the upper pivot at the rear of the boom.

  The upper end of the boom and the upper end of the lattice mast are connected by a boom guy line and a boom relief rope. Since the distance between the upper end of the boom and the upper end of the lattice mast is increased by the unwinding of the boom hoisting rope, the boom is laid down. On the other hand, since the distance between the upper end of the boom and the upper end of the lattice mast is reduced by winding the boom hoisting rope, the boom is erected.

  The connecting member has a mast support cable and a mast hoist rope. Since the distance between the upper end of the lattice mast and the upper swing body is increased by the delivery of the mast hoisting rope, the lattice mast is pivoted forward. On the other hand, since the distance between the upper end portion of the lattice mast and the upper swing body is reduced by winding the mast hoisting rope, the lattice mast is rotated rearward.

  The weight carriage is a weight for generating a rear moment (a moment for rotating the lattice mast such that the upper end of the lattice mast is directed rearward) about the lower end of the lattice mast with respect to the lattice mast. This backward moment corresponds to the forward moment around the lower end acting on the lattice mast via the boom, the boom guy line and the boom undulation rope (the moment for rotating the lattice mast so that the upper end of the lattice mast is directed forward) It is.

JP, 2009-67578, A

  In a crane as described in Patent Document 1, when raising the boom when assembling the crane, or when laying down the boom when storing the crane, the lattice mast and the upper revolving structure are insufficient if the weight is insufficient. The tension acting on the connecting member connecting the Specifically, when raising and lowering the boom, a forward moment around the lower end is generated in the lattice mast due to the boom pulling the upper end of the lattice mast forward through the boom guy line and the boom undulation rope Do. Therefore, when the weight (back moment around the lower end) of the weight is insufficient, the lattice mast tries to rotate so that the upper end of the lattice mast is directed forward. For this reason, the tension acting on the connecting member is increased.

  An object of the present invention is to provide a crane and its operating method capable of suppressing the application of excessive tension to a connecting member.

  As means for solving the above problems, the present invention provides a crane main body, a boom which can be raised and lowered relative to the crane main body, and can be turned relative to the crane main body at a position behind the boom. The upper end of the boom and the upper end of the mast are connected to the crane main body, and the distance between the mast for raising and lowering the boom and the upper end of the boom and the upper end of the mast is changed And a boom hoisting winch for winding and unwinding the boom hoisting rope such that the distance between the upper end of the boom and the upper end of the mast is changed, and the upper end of the mast And a connecting member for connecting a portion of the crane main body located behind the lower end portion of the mast and a web which can be detachably connected to the mast A rear moment, which is a moment for rotating the mast such that the upper end of the mast is directed rearward about the lower end of the mast when connected to the mast, And a tension detection unit that detects a state of tension generated in the connection member, and a winch control unit that stops the boom hoisting winch when the detection value of the tension detection unit becomes equal to or greater than a threshold. Provide a crane.

  In this crane, since the boom hoisting winch is stopped when the detection value of the tension detecting unit for detecting the state of tension generated in the connecting member becomes equal to or more than the threshold, the boom hoisting thereafter is stopped. Therefore, the tension generated in the connecting member is suppressed from being excessive.

  In this case, the winch control unit further includes an operation direction detection unit for detecting the operation direction of the boom, and the winch control unit is detected by the operation direction detection unit when the detection value of the tension detection unit becomes equal to or more than the threshold. The driving of the boom hoisting winch is inhibited when it is detected by the operating direction detection unit that the boom is operated in the same direction as the operation direction, and the detection value of the tension detection unit is the threshold value. When the operation direction detection unit detects that the boom is being operated in the direction opposite to the operation direction detected by the operation direction detection unit, the boom undulation winch is driven. It is preferable to allow.

  In this way, the boom operation in the direction opposite to the boom operation direction when the detection value of the tension detection unit becomes equal to or greater than the threshold, that is, the boom in the direction in which the detection value of the tension detection unit decreases. Since the operation is permitted, the tension generated in the connecting member is effectively reduced.

  In addition, in the crane, a storage unit that stores information indicating a relationship between the boom and the weight of the weight for generating the rear moment necessary to raise or fall the boom, and the tension detection unit. It is preferable to further include a notification unit that notifies a value based on a value obtained from the boom and the information as the weight of the weight when the detected value of becomes equal to or more than the threshold.

  In this way, when the detection value of the tension detection unit becomes equal to or more than the threshold value, the boom hoisting and lowering winch is stopped, and the rear moment necessary to raise or lower the boom mounted at that time is The weight of the weight to be generated is notified to a monitor or the like in the cabin. Thus, when the boom hoisting winch stops, installation of a weight having a weight necessary to raise or lower the boom is facilitated.

  Further, the present invention is connected to the crane main body so as to be rotatable relative to the crane main body at a position behind the crane main body, the boom which can be raised and lowered relative to the crane main body, and the boom. A mast for raising and lowering the boom, and a boom hoisting rope connected to the upper end of the boom and the upper end of the mast such that the distance between the upper end of the boom and the upper end of the mast is changed A boom hoisting winch for winding and unwinding the boom hoisting rope such that a distance between an upper end of the boom and an upper end of the mast is changed; a mast of the upper end of the mast and the crane main body A connecting member for connecting a portion located rearward of the lower end portion of the gear, and a weight detachably connectable to the mast, wherein the weight is connected to the mast Generating an aft moment on the mast which is a moment to turn the mast so that the upper end of the mast is directed rearward about the lower end of the mast in the closed state. There is provided a method of operating a crane, including a stopping step of stopping the boom hoisting winch when a value of tension generated in the connecting member becomes equal to or more than a threshold.

  Also in this method, excessive tension generated in the connecting member is suppressed.

  Further, in the stopping step, the driving of the boom hoisting winch is prohibited when the boom is operated in the same direction as the operating direction of the boom when the value of the tension becomes the threshold or more. It is preferable to allow driving of the boom hoisting winch when the boom is operated in the direction opposite to the operating direction of the boom when the tension value becomes equal to or more than the threshold value.

  As described above, according to the present invention, it is possible to provide a crane capable of suppressing the application of excessive tension to a connecting member and a method of operating the same.

It is a side view showing the state where the boom of the crane of one embodiment of the present invention turned up. It is a side view which shows the state which the boom of the crane shown by FIG. 1 turned into the lying posture. Figure 2 is a schematic view of the controller of the crane shown in Figure 1; It is a figure which shows the flowchart which shows the control content of a controller. It is a flowchart which shows the content of the normal operation processing. It is a flowchart which shows the content of upper stop processing. It is a flow chart which shows the contents of lower stop processing. It is a flowchart which shows the content of last time value processing.

  A crane according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8.

  FIG. 1 shows the entire configuration of the crane of this embodiment. Specifically, this crane comprises an upper revolving superstructure 1 corresponding to a crane main body, a lower traveling vehicle 2 pivotably supporting the upper revolving superstructure 1, a boom 10, a mast 20, a boom guy line 32, and a boom relief. A rope 34, a boom hoisting winch 38, a connecting member 40, and a weight 50 are provided.

  The lower end portion of the boom 10 is attached to the upper swing body 1 so that the boom 10 can be raised and lowered relative to the upper swing body 1. Specifically, the lower end of the boom 10 is connected to the front end of the upper swing body 1. The boom 10 has a lattice structure. The boom 10 is operated by an operation member (operation lever or the like) capable of raising or lowering the boom 10. The operation member is provided in a cabin (not shown) mounted on the upper swing body 1.

  A hook 8 for suspending a suspended load is suspended from the boom 10. The hook 8 is suspended by the main winding rope 5 via a sheave 7 attached to the upper end of the boom 10. On the upper revolving superstructure 1, a main winding winch 3 for winding and feeding the main winding rope 5 is mounted.

  The mast 20 is a member for raising and lowering the boom 10. In this embodiment, as the mast 20, one having a lattice structure (hereinafter, referred to as "lattice mast 20") is used. The lattice mast 20 is connected to the upper structure 1 so as to be rotatable relative to the upper structure 1 at a position behind the boom 10. The lower end of the lattice mast 20 is connected to the front end of the upper swing body 1. The mast is not limited to the lattice mast.

  The boom guy line 32 and the boom undulation rope 34 connect the upper end of the boom 10 and the upper end of the lattice mast 20. Specifically, one end of the boom guy line 32 is connected to the upper end of the boom 10. The other end of the boom guy line 32 is connected to the upper spreader 35. The boom relief rope 34 is wound around a lower spreader 36 and an upper spreader 35 connected to the upper end of the lattice mast 20.

  The boom hoisting winch 38 winds and feeds the boom hoisting rope 34. In the present embodiment, the boom hoisting winch 38 is attached to the lower part of the lattice mast 20. Since the boom undulation winch 38 rolls up the boom undulation rope 34, the distance between the upper spreader 35 and the lower spreader 36, that is, the distance between the upper end of the boom 10 and the upper end of the lattice mast 20 decreases. Rotate in the direction in which the Conversely, when the boom undulation winch 38 feeds the boom undulation rope 34, the distance between the upper spreader 35 and the lower spreader 36, that is, the distance between the upper end of the boom 10 and the upper end of the lattice mast 20 increases. The boom 10 pivots in the falling direction. 1 shows the boom 10 in the standing posture (workable posture), and FIG. 2 shows the boom 10 in the lying posture (the posture in which the tip of the boom 10 is in contact with the ground).

  The connecting member 40 connects the lattice mast 20 and a portion of the upper swing body 1 located rearward of the lower end portion of the lattice mast 20. Specifically, one end of the connecting member 40 is connected to the upper end of the lattice mast 20, and the other end of the connecting member 40 is connected to the rear end of the upper swing body 1. In the present embodiment, the connecting member 40 has a mast connecting rope 42 and a mast hoisting rope 44.

  The mast connecting rope 42 connects the upper end of the lattice mast 20 and the upper end of the crane mast 46. The crane mast 46 is connected to the front end of the upper structure 1 so as to be rotatable relative to the upper structure 1 at the rear of the lattice mast 20.

  The mast hoisting rope 44 is wound around a sheave 47 connected to the upper end of the crane mast 46 and a sheave 48 connected to the rear end of the upper swing body 1. The winding and unwinding of the mast hoisting rope 44 is performed by a mast hoisting winch 39 mounted on the upper swing body 1. Specifically, when the mast hoisting winch 39 winds up the mast hoisting rope 44, the distance between the upper end of the crane mast 46 and the upper revolving unit 1, that is, the distance between the upper end of the lattice mast 20 and the upper revolving unit 1 is Since the lattice mast 20 becomes smaller, the lattice mast 20 pivots (falls) rearward (left side in FIG. 1). Conversely, when the mast hoisting winch 39 feeds the mast hoisting rope 44, the distance between the upper end of the crane mast 46 and the upper revolving unit 1, that is, the distance between the upper end of the lattice mast 20 and the upper revolving unit 1 is large. As a result, the lattice mast 20 pivots (stands up) forward (right side in FIG. 1).

  The weight 50 is connected to the upper end of the lattice mast 20 via a weight connection cable 52. The weight 50 is a weight for generating, with respect to the lattice mast 20, a rear moment (a moment that causes the upper end of the lattice mast 20 to face rearward) around the lower end of the lattice mast 20. The rear moment is when the weight 50 is lifted by the weight connection cable 52 and the weight connection cable 20 is under tension when the weight 50 lifts up the suspended load via the weight connection cable 52, It occurs on the lattice mast 20. In addition, even when the weight 50 does not go up and the weight 50 is not lifted up, the rear moment is generated in the lattice mast 20 even when the lattice mast 20 is rotated forward and the connecting cable 52 is under tension. Do. The rearward moment corresponds to the forward moment about the lower end acting on the lattice mast 20 via the boom 10, the boom guy line 32 and the boom undulation rope 34. The weight of the weight 50 can be changed by adding a weight or the like.

  Next, the method of assembling the crane described above will be described. As shown in FIG. 2, before the crane is assembled, the boom 10 is in the lying posture and the weight 50 is suspended from the upper end of the lattice mast 20. In this state, the boom hoisting rope 34 is wound up by the boom hoisting winch 38. As a result, the distance between the upper end of the lattice mast 20 and the tip of the boom 10 is reduced, so that the boom 10 is erected. At this time, a forward moment around the lower end of the lattice mast 20 is generated in the lattice mast 20. On the other hand, since the weight 50 is connected to the lattice mast 20, a rear moment around the lower end is also generated in the lattice mast 20. For this reason, while the boom undulation rope 34 is taken up by the boom undulation winch 38, the boom 10 stands up with almost no rotation of the lattice mast 20.

  In the crane assembled in this manner, when the weight 50 is connected to the lattice mast 20, or when it is necessary to turn the upper structure 1, the weight 50 is separated from the lattice mast 20. May be

  Then, the method of storing a crane is demonstrated. When the crane is stored, the boom 10 is changed from the standing posture to the lying posture with the weight 50 connected to the lattice mast 20. Specifically, the boom hoisting rope 34 is fed out by the boom hoisting winch 38 while the boom 10 is in the standing posture. As a result, the distance between the upper end of the lattice mast 20 and the tip of the boom 10 is increased, and the boom 10 is laid down. At this time, as in the case of the above-described assembly, a forward moment due to the weight of the boom 10 and a rear moment due to the weight of the weight 50 are generated on the lattice mast 20. For this reason, while the boom undulation rope 34 is fed out by the boom undulation winch 38, the boom 10 falls with almost no rotation of the lattice mast 20.

  Here, if the weight 50 is not attached to the lattice mast 20 at the time of assembling or storing the crane, or if the weight 50 is insufficient, winding the boom relief rope 34 by the boom relief winch 38 or The lattice mast 20 tries to rotate forward because a backward moment is not generated in the lattice mast 20 that is balanced with the forward moment generated in the lattice mast 20 due to the delivery. As a result, the tension acting on the connecting member 40 gradually increases as the boom undulation rope 34 is wound or unwound by the boom undulation winch 38.

  The crane of the present embodiment is configured to be able to suppress the application of excessive tension to the connecting member 40. Specifically, the crane includes a tension detection unit 62 (see FIGS. 1 and 2) and a controller 64 (see FIG. 3).

  The tension detection unit 62 is provided on the connection member 40 and detects the tension acting on the connection member 40. In the present embodiment, a load cell is used as the tension detection unit 62. The load cell is provided at the lower end of the mast connecting rope 42.

  The controller 64 includes a winch control unit 65, an alarm transmission unit 66, a storage unit 67, and a notification unit 68.

  The winch control unit 65 stops the boom hoisting winch 38 when the tension acting on the connecting member 40, that is, the detection value T of the tension detection unit 62 becomes equal to or more than the threshold value T2. More specifically, the winch control unit 65 prohibits the driving of the boom hoisting winch 38 when the operation member is operated in the same direction as the operation direction of the operation member when the detection value T becomes equal to or greater than the threshold value T2. At the same time, driving of the boom hoisting winch 38 is permitted when the operating member is operated in the direction opposite to the operating direction of the operating member when the detection value T becomes equal to or greater than the threshold value T2. The operation direction of the operation member is detected by the operation direction detection unit 63 capable of detecting the operation direction. The operation direction detection unit 63 sends a signal (hereinafter referred to as a "raising operation signal") indicating that the operation member is operated in the direction to raise the boom 10 to the winch control unit 65, and the operation member Sends a signal (hereinafter referred to as a "lowering operation signal") to the winch control unit 65 to indicate that the boom 10 is being operated in the direction to lay it down. That is, the winch control unit 65 operates the same operation signal as the operation signal (raising operation signal or lowering operation signal) received from the operation direction detection unit 63 when the detection value T becomes equal to or greater than the threshold T2. In addition to prohibiting the driving of the boom hoisting winch 38 when receiving from 63 and operating the operation signal different from the operation signal received from the operation direction detection unit 63 when the detection value T becomes the threshold value T2 or more The driving of the boom hoisting winch 38 when receiving from the direction detection unit 63 is permitted. For example, when the detection value T received from the tension detection unit 62 becomes equal to or more than the threshold value T2 during reception of the raising operation signal from the operation direction detection unit 63, the winch control unit 65 raises the boom 10 in the direction of raising the boom 10. Only the drive of the winch 38 (winding of the boom undulation rope 34) is prohibited, while the drive of the boom undulation winch 38 in the direction of laying down the boom 10 (protraction of the boom undulation rope 34) is permitted. In addition, the operation direction detection unit 63 also sends the raising operation signal and the lowering operation signal to the alarm transmission unit 66.

  The alarm transmission unit 66 emits an alarm (buzzer) in the cabin when the detection value T of the tension detection unit 62 becomes equal to or more than the threshold value T2. More specifically, the alarm transmission unit 66 receives the operation from the operation direction detection unit 63 when the detection value T of the tension detection unit 62 is the threshold T2 or more and the detection value T is the threshold T2 or more. While the reception of the same operation signal as the signal (the raising operation signal or the lowering operation signal) is continued, the alarming is continued.

  The storage unit 67 sets the relationship between the boom 10 and the weight of the weight 50 for generating the rear moment necessary for changing the boom 10 from the standing posture to the lying posture or from the lying posture to the standing posture. The information (map) to show is memorized. The storage unit 67 transmits the information to the notification unit 68.

  The notification unit 68 transmits error information to the monitor 69 provided in the cabin when the detection value T of the tension detection unit 62 becomes equal to or greater than the threshold value T2. The error information is a value obtained based on the stop of the boom hoisting winch 38 due to a large tension acting on the connecting member 40 and the information received from the boom 10 and the storage unit 67 (the boom 10 And the weight of the weight 50 capable of generating a rear moment necessary to turn it between the standing posture and the lying posture. That is, when the detection value T of the tension detection unit 62 becomes equal to or more than the threshold value T2, the boom 69 is stopped on the monitor 69 because the tension acting on the connecting member 40 is large, and The weight of the weight 50 required to rotate the mounted boom 10 between the upright posture and the fallen posture is displayed. The weight of the weight 50 displayed on the monitor 69 may be the weight (absolute value) of the weight 50 necessary for rotating the currently mounted boom 10 between the standing posture and the lying posture, or The difference between the weight and the weight of the weight 50 currently suspended may be used.

  Hereinafter, the specific control flow of the controller 64 will be described with reference to FIGS. 4 to 8.

  As shown in FIG. 4, first, the controller 64 determines whether the weight 50 is connected to the lattice mast 20 (step S11). As a result, when the weight 50 is connected to the lattice mast 20, the controller 64 determines whether or not the detection value T of the tension detection unit 62 is equal to or greater than a reference value T1 smaller than the threshold T2 (step S13). ). As a result, if the detected value T is greater than or equal to the reference value T1, the controller 64 determines whether it is greater than or equal to the threshold T2 (step S16). As a result, when the detected value T is equal to or greater than the threshold value T2, that is, when a relatively large tension is applied to the connecting member 40, the controller 64 receives the raising operation signal from the operation direction detecting unit 63. It is determined whether or not there is (step S17). As a result, when the raising operation signal is received (the operation member is operated in the direction to raise the boom 10), the controller 64 sets the upper stop flag as the previous value flag (step S18), and stops the upper stop. In the process (step S19), when the raising operation signal is not received, in other words, when the lowering operation signal is received (the operation member is operated in the direction to tilt the boom 10), The controller 64 sets the lower stop flag as the previous value flag (step S20), and shifts to the lower stop process (step S21).

  The upper stop processing prohibits the operation of the operation member in the same direction when the detection value T of the tension detection unit 62 reaches the threshold T2 during the operation of the operation member in the direction in which the boom 10 is raised. Control. The control of the upper stop processing will be described with reference to FIG. When the upper stop processing is started, the winch control unit 65 of the controller 64 only stops driving of the boom hoisting winch 38 (winding of the boom hoisting rope 34) in the direction to raise the boom 10 (step S111). Then, the controller 64 determines whether the reception of the raising operation signal from the operation direction detection unit 63 is continued (step S112). As a result, when the reception of the raising operation signal is continued, the alarm transmitting unit 66 of the controller 64 issues an alarm (step S113), whereas when the reception of the raising operation signal is not continued, the alarm transmitting unit 66 , Stop the alarm (step S114). For this reason, the operator in the cabin is urged to stop the operation of the operation member in the direction in which the boom 10 stands up. Then, the notification unit 68 of the controller 64 transmits the error information to the monitor 69. Therefore, the operator in the cabin is prompted to adjust the weight of the weight 50 so that the weight of the weight 50 becomes appropriate based on the display of the monitor 69. The upper stop process is completed, and the process returns to the start again.

  The lower stop process prohibits the operation of the operation member in the same direction when the detection value T of the tension detection unit 62 reaches the threshold T2 during the operation of the operation member in the direction in which the boom 10 falls. Control. The lower stop processing will be described with reference to FIG. When the lower stop process is started, the winch control unit 65 of the controller 64 stops only the driving of the boom hoisting winch 38 (the delivery of the boom hoisting rope 34) in the direction in which the boom 10 is laid down (step S121). Then, the controller 64 determines whether the reception of the lowering operation signal from the operation direction detection unit 63 is continued (step S122). As a result, when the reception of the lowering operation signal is continued, the alarm transmitting unit 66 of the controller 64 issues an alarm (step S123), and when the reception of the lowering operation signal is not continued, the alarm transmitting unit 66 , Stop the alarm (step S124). For this reason, the operator in the cabin is urged to stop the operation of the operation member in the direction in which the boom 10 falls. Then, the notification unit 68 of the controller 64 transmits the error information to the monitor 69. Therefore, the operator in the cabin is prompted to adjust the weight of the weight 50 so that the weight of the weight 50 becomes appropriate based on the display of the monitor 69. Thus, the lower stop process is completed and the process returns to the start again.

  Here, based on the alarm or error information received in the upper stop processing or the lower stop processing, the worker reverses the operation direction of the operation member when the detection value T of the tension detection unit 62 becomes equal to or greater than the threshold T2. The operation of the operation member or the addition of the weight 50 is performed. As a result, the detection value T of the tension detection unit 62 becomes smaller.

  When the detected value T is less than the threshold value T2 (NO in step S16), the controller 64 shifts to the previous value processing (step S22).

  The previous value processing is control for causing the detection value T of the tension detection unit 62 to have hysteresis. The previous value processing will be described with reference to FIG. When the previous value process is started, the controller 64 determines whether the previous value flag is a normal flag (step S131). As a result, when the previous value flag is the normal flag, the controller 64 shifts to the normal operation processing (step S132). The normal operation processing will be described later. On the other hand, if the previous value flag is not the normal flag (NO in step S131), the controller 64 determines whether the previous value flag is the upper stop flag (step S133). As a result, when the previous value flag is the upper stop flag, the controller 64 shifts to the upper stop process (step S134). That is, although the detection value T has fallen below the threshold value T2, the state in which the operation in the direction of raising the boom 10 is still prohibited is maintained. On the other hand, when the previous value flag is not the upper stop flag (NO in step S133), the controller 64 shifts to the lower stop process (step S135). That is, although the detection value T is reduced to less than the threshold value T2, the state in which the operation in the direction in which the boom 10 is laid is still prohibited is maintained.

  For this reason, the operator operates the operation member in the direction in which the detection value T of the tension detection unit 62 is further lowered, or adds the weight of the weight 50. As a result, the detection value T of the tension detection unit 62 is further reduced.

  When the detected value T is less than the reference value T1 (NO in step S13), that is, when the connecting member 40 does not have a large tension applied thereto, the controller 64 normally uses the previous value flag as a flag. A flag is set (step S14), and the process proceeds to normal operation processing (step S15).

  Here, the normal operation processing will be described with reference to FIG. When the normal operation process is started, the controller 64 enables driving of the boom hoisting winch 38 in both the direction in which the boom 10 is raised and the direction in which the boom 10 is laid down (step S101). Then, the alarm transmission unit 66 of the controller 64 stops the transmission of the alarm (buzzer) (step S102), and the notification unit 68 of the controller 64 stops transmission of the error information to the monitor 69 (step S103). Thus, the normal operation processing is completed, and the process returns to the start again. Steps S101 to S103 may be performed in any order, or may be performed simultaneously.

  As described above, in the crane of the present embodiment, the boom hoisting winch 38 is stopped when the detection value T of the tension detection unit 62 for detecting the state of tension generated in the connecting member 40 becomes equal to or greater than the threshold T2. As a result, the rising or falling of the boom 10 thereafter is stopped. Therefore, the tension generated in the connecting member 40 is suppressed from being excessive.

  Further, the winch control unit 65 operates the same operation signal as the operation signal (raising operation signal or lowering operation signal) received from the operation direction detection unit 63 when the detection value T becomes equal to or greater than the threshold value T2. In addition to prohibiting the driving of the boom hoisting winch 38 when receiving from 63 and operating the operation signal different from the operation signal received from the operation direction detection unit 63 when the detection value T becomes the threshold value T2 or more The driving of the boom hoisting winch 38 when receiving from the direction detection unit 63 is permitted. Therefore, the operation of the boom 10 in the direction opposite to the operation direction of the boom 10 when the detection value T of the tension detection unit 62 becomes equal to or greater than the threshold T2, that is, the direction in which the detection value T of the tension detection unit 62 decreases. Operation of the boom 10 is permitted. Thus, the tension generated in the connecting member 40 is effectively reduced.

  Furthermore, the notification unit 68 of the controller 64 obtains a value obtained from the boom 10 currently attached and the information stored in the storage unit 67 when the detection value T of the tension detection unit 62 becomes equal to or greater than the threshold T2. Based on this, the monitor 69 is notified of the weight of the weight 50 required to turn the boom 10 between the standing posture and the lying posture. Therefore, when the detection value T of the tension detection unit 62 becomes equal to or greater than the threshold value T2, installation of the weight 50 having a weight necessary for raising or lowering the boom 10 becomes easy when the boom hoisting winch 38 stops. .

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the description of the embodiments described above but by the claims, and further includes all modifications within the meaning and scope equivalent to the claims.

  For example, the connecting member 40 may be constituted by a single guy line connecting the upper end of the lattice mast 20 and the rear end of the upper swing body 1.

1 Upper revolving unit (crane body)
10 boom 20 mast (lattice mast)
32 boom guy link 34 boom relief rope 38 boom relief winch 40 connecting member 42 mast connecting rope 44 mast relief rope 50 weight 62 tension detector 63 operation direction detector 64 controller 65 winch controller 66 alarm transmitter 67 memory 68

Claims (5)

With the crane body,
A boom which can be raised and lowered relative to the crane body;
A mast connected to the crane body so as to be rotatable relative to the crane body at a position behind the boom, for raising and lowering the boom;
A boom hoisting rope connected to the upper end of the boom and the upper end of the mast such that the distance between the upper end of the boom and the upper end of the mast is changed;
A boom hoisting winch for winding and unwinding the boom hoisting rope such that the distance between the upper end of the boom and the upper end of the mast is changed;
A connecting member for connecting the upper end of the mast and a portion of the crane main body located rearward of the lower end of the mast;
A weight which can be detachably connected to the mast, and in a state of being connected to the mast, a moment for pivoting the mast such that the upper end of the mast is directed rearward about the lower end of the mast Generating an aft moment on the mast which is
A tension detection unit that detects a state of tension generated in the connection member;
A crane comprising: a winch control unit configured to stop the boom hoisting winch when a detection value of the tension detection unit becomes equal to or greater than a threshold. In the crane according to claim 1,
It further comprises an operation direction detection unit for detecting the operation direction of the boom,
The winch control unit is configured to operate the boom in the same direction as the operation direction detected by the operation direction detection unit when the detection value of the tension detection unit becomes equal to or more than the threshold value. The driving of the boom undulation winch when detected by the detection unit is prohibited, and when the detection value of the tension detection unit becomes equal to or more than the threshold value, the operation direction detection unit reverses the operation direction detected by the operation direction detection unit. A crane which allows driving of the boom hoisting winch when it is detected by the operating direction detection unit that the boom is operated in a direction. In the crane according to claim 1 or 2,
A storage unit that stores information indicating a relationship between the boom and the weight of the weight for generating the rear moment necessary to raise or fall the boom;
And a notification unit that notifies a value based on the value obtained from the boom and the information as the weight of the weight when the detection value of the tension detection unit becomes equal to or more than the threshold. A crane body, a boom that can be raised and lowered with respect to the crane body, and a crane body that is connected to the crane body so as to be rotatable with respect to the crane body at a position behind the boom A boom hoisting rope connected to the upper end of the boom and the upper end of the mast such that the distance between the upper end of the boom and the upper end of the mast is changed; and the upper end of the boom And a boom hoisting winch for winding and unwinding the boom hoisting rope so that the distance between the upper ends of the mast is changed, the upper end of the mast and the rear of the lower end of the mast of the crane main body A connecting member for connecting to a portion located at a position of the vehicle, and a weight which can be detachably connected to the mast, the state member being connected to the mast The upper end of the mast is a method of operating a crane comprising as to generate a backward moment is a moment to rotate the mast so as to be directed rearward to the mast, the around the lower portion of the mast,
A method of operating a crane, comprising a stopping step of stopping the boom hoisting winch when a value of tension generated in the connecting member becomes equal to or more than a threshold. In the method of operating a crane according to claim 4,
In the stopping step, driving of the boom hoisting winch is prohibited when the boom is operated in the same direction as the operation direction of the boom when the value of the tension becomes equal to or more than the threshold value. A method of operating a crane, wherein driving of the boom hoisting winch is permitted when the boom is operated in the direction opposite to the operating direction of the boom when the value becomes equal to or higher than the threshold value.

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