JP2018016442A - crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a hanging performance by changing a moment generated from a counterweight unit while suppressing a lateral width of a crane.SOLUTION: A crane includes: a travelling body; a rotation body provided in an upper part of the travelling body so as to be rotatable; a boom provided in the rotation body; a counterweight unit disposed in a rear part of the crane; and a rotating device for rotating the counterweight unit within a vertical plane.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a crane.

  A crane is known that includes a counterweight unit moving device coupled between a rotating bed and a counterweight unit in order to move the counterweight unit closer to or away from the boom (see Patent Document 1). ).

JP 2011-37634 A

  The counterweight unit described in Patent Document 1 supports the counterweight so as to be movable in the front-rear direction on both the left and right sides of the counterweight support frame. For this reason, in the structure of patent document 1, the left-right width of a crane will become large.

  A crane according to an aspect of the present invention is a crane including a traveling body, a revolving body provided on an upper portion of the traveling body, and a boom provided on the revolving body. The counterweight unit is arranged, and a rotating device that rotates the counterweight unit in a vertical plane.

  According to the present invention, the suspension performance can be improved by changing the moment generated by the counterweight unit while suppressing the lateral width of the crane.

The external appearance side view of a crane. The side surface schematic diagram which expands and shows the rear part of a crane. The block diagram for demonstrating rotation control of the counterweight unit in the crane which concerns on 1st Embodiment. (A) is a figure explaining the calculation method of the front fall moment Mf1 and the back stable moment Mb2 at the time of rotating a counterweight unit back according to the fall operation of a boom, (b) A counter according to the standing operation of a boom The figure explaining the calculation method of the backward fall moment Mb1 and the front stable moment Mf2 at the time of rotating a weight unit ahead. The flowchart which shows the processing content of rotation control by the controller which concerns on 1st Embodiment. The figure explaining the attachment or detachment method of a counterweight unit. The figure explaining the slide mechanism and slide operation | movement of a counterweight unit. The block diagram for demonstrating the slide movement control of the counterweight unit in the crane which concerns on 2nd Embodiment. The flowchart which shows the processing content of the slide movement control by the controller which concerns on 2nd Embodiment.

-First embodiment-
An embodiment of a crane according to the present invention will be described with reference to the drawings. FIG. 1 is an external side view of a crane. Below, it defines so that up and down, front and back, and the left-right direction may be illustrated on the basis of the working posture of FIG. The crane 100 is rotatably provided on a traveling body 101, a revolving body 103 that is turnable via a turning wheel on an upper portion of a frame that forms the traveling body 101, and a main frame 150 that forms the revolving body 103. The boom 104 is provided.

  The swivel body 103 is provided with an operator cab 103a, and a hoisting winch 105 and a hoisting winch 106 are mounted thereon. A hoisting rope 105 a is wound around the hoisting winch 105, and the hoisting rope 105 a is wound or unwound by driving the hoisting winch 105, and the suspended load 108 suspended from the hook 107 moves up and down. A hoisting rope 106 a is wound around the hoisting winch 106, and when the hoisting winch 106 is driven, the hoisting rope 106 a is wound or fed out, and the boom 104 is raised and lowered.

  The swivel body 103 includes an actuator such as a hydraulic pump (not shown) that is driven by the engine and discharges pressure oil, a hydraulic motor that is driven by pressure oil discharged from the hydraulic pump, and pressure oil supplied to the actuator. A hydraulic circuit having a hydraulic device such as a control valve for controlling the flow is mounted.

  The main frame 150 constituting the revolving structure 103 is provided so as to extend in the front-rear direction at the center in the left-right direction of the crane 100. The main frame 150 is a welded structure made of a flat plate, a shape steel, or the like, and is formed in a rectangular frame shape. A bed 170 that is a support structure that supports the building 171 is connected to the left and right sides of the main frame 150. Boom foot pins are connected to the pair of left and right boom support portions at the front end portion of the main frame 150, and the boom 104 is rotatably supported. Various winches are mounted on the main frame 150.

  FIG. 2 is an enlarged schematic side view of the rear part of the crane. FIG. 2A shows the first posture of the counterweight unit 120, and FIG. 2B shows the second posture of the counterweight unit 120. As shown in FIG. 2, the counterweight unit 120 is between the first posture (see FIG. 2A) of the counterweight unit 120 and the second posture of the counterweight unit 120 (see FIG. 2B). Rotate 90 degrees.

  As shown in FIG. 2B, the base 140 is fixed to the rear end portion of the main frame 150. The base 140 extends rearward from the main frame 150. The base 140 is provided with a counterweight device 110. As shown in FIGS. 2A and 2B, the counterweight device 110 includes a counterweight unit 120 and a weight rotating device 130 that rotates the counterweight unit 120. The counterweight unit 120 is located on the central axis of the main frame 150 extending in the front-rear direction so as to divide the main frame 150 into left and right. The left and right outer edges of the counterweight unit 120 are located inside the left and right outer edges of the left and right buildings 171. That is, the left-right width of the counterweight unit 120 is shorter than the dimension between the outer surfaces of the building 171 or the bed 170 on both the left and right sides. The counterweight unit 120 includes a plurality of weights 111 and a weight support frame 112 that supports the plurality of weights 111.

  The weight support frame 112 is a support structure in which various shape steels such as H-shape steel, I-shape steel, angle steel, groove-shape steel, square-shape steel, and the like are firmly coupled by welding or bolts. The weight support frame 112 includes a pair of left and right L-shaped frames 113 and a connecting member 114 that connects the pair of L-shaped frames.

  The L-shaped frame 113 includes a first support portion 113a and a second support portion 113b provided perpendicular to the first support portion 113a, and has an L shape in a side view. The first support portion 113a is disposed in parallel in the front-rear horizontal direction in the first posture, and is disposed in parallel in the vertical (vertical) direction in the second posture. The second support portion 113b is disposed in parallel with the vertical (vertical) direction in the first posture, and is disposed in parallel with the front-rear horizontal direction in the second posture.

  The distance between the pair of left and right L-shaped frames 113 is wider than the left and right width of the base 140, and the first support portion 113a is disposed outside the left and right sides of the base 140 in the first posture.

  The plurality of connecting members 114 extend in the left-right horizontal direction, both ends are connected to the pair of left and right second support portions 113b, and the pair of left and right second support portions are connected to each other. The connecting member 114 is, for example, a rectangular hollow rectangular steel, and rib plates are welded at predetermined intervals in the left-right direction. The connecting member 114 is provided with a through hole into which a bolt 119 described later is inserted.

  The plurality of weights 111 are supported by the weight support frame 112 in a stacked arrangement. Each weight 111 is provided with a through hole through which the bolt 119 is inserted. Bolts 119 are inserted through the through holes of the connecting members 114 of the weights 111 and the weight support frames 112, and nuts are attached to the screw portions at the ends of the bolts 119. And the connecting member 114 are clamped, and each weight 111 is firmly fixed to the weight support frame 112. The plurality of weights 111 are stacked in the front-rear horizontal direction when in the first posture, and stacked in the vertical (vertical) direction when in the second posture. The bolt 119 extends in the stacking direction.

  The weight rotation device 130 includes a control valve that controls the flow of the pressure oil discharged from the hydraulic pump described above, and a pair of left and right hydraulic motors that are driven by the pressure oil supplied via the control valve. Yes. Each hydraulic motor and control valve are housed in the rear end of the base 140. A rotary shaft 131 is connected to the output shaft of each hydraulic motor, and the rotary shaft 131 is rotated by the rotation of the hydraulic motor. The rotation shaft 131 of each hydraulic motor is coupled to a corner portion of the L-shaped frame 113, that is, a coupling portion provided at a boundary portion between the first support portion 113a and the second support portion 113b via a gear or the like.

  The rotation center axis of the rotation shaft 131 extends in the horizontal direction, and when the hydraulic motor of the weight rotation device 130 rotates, the counterweight unit 120 disposed at the rear of the crane 100 rotates in the vertical plane. To do. Here, the vertical plane refers to a virtual plane orthogonal to the rotation center axis of the rotation shaft 131. When the hydraulic motor stops, the counterweight unit 120 is held at a predetermined angle. When the counterweight unit 120 rotates 90 degrees backward from the first posture, it shifts to the second posture.

  FIG. 3 is a block diagram for explaining rotation control of the counterweight unit in the crane according to the first embodiment. The controller 180 is a control device that includes an arithmetic processing unit having a storage device such as a CPU, ROM, and RAM, and other peripheral circuits, and controls each part of the crane 100. The storage device of the controller 180 stores geometric information such as the shape and dimensions of the crane 100 and information such as the weight of each member.

  An operation device 191, a display device 192, a load meter 193, a boom angle sensor 194, an input device 195, and a weight angle sensor 196 are connected to the controller 180. The operating device 191 and the display device 192 are provided in the cab 103a (see FIG. 1). The operation device 191 includes an operation lever that operates each winch and a sensor that detects an operation amount of the operation lever, and outputs a detected operation amount signal of the operation lever to the controller 180. Based on the display control signal from the controller 180, the display device 192 displays a display image representing various types of crane work information on the display screen.

  The load meter 193 detects a suspended load and includes, for example, a load cell that detects the tension of the hoisting rope 106 a and outputs the detected tension signal to the controller 180. The boom angle sensor 194 is provided at the base end portion of the boom 104, detects the boom angle that is the ground angle of the boom 104, and outputs the detected angle signal to the controller 180. The controller 180 detects the boom angle based on the signal from the boom angle sensor 194.

  The input device 195 outputs a predetermined input signal to the controller 180 based on an operation by the operator. The input device 195 outputs a signal corresponding to information related to the specifications of the crane 100 such as the length of the boom 104 and the size of the hook 107 to the controller 180, for example.

  The weight angle sensor 196 is, for example, a potentiometer provided in the vicinity of the output shaft of the hydraulic motor of the weight rotation device 130, detects the rotation angle of the counterweight unit 120, and outputs the detected angle signal to the controller 180. To do.

  The controller 180 functionally includes a calculation unit 181 and a rotation control unit 182. The calculation unit 181 calculates the suspension load WL based on the tension of the hoisting rope 106a. The calculation unit 181 calculates a work radius based on the length of the boom 104 and the boom angle.

  The controller 180 obtains a limit load corresponding to the calculated work radius using the rated load curve stored in the storage device, and compares the limit load with the calculated suspension load so that the crane 100 does not fall down. It has a function of restricting driving of each winch 105,106.

  The calculating unit 181 calculates a forward overturning moment Mf1, a backward overturning moment Mb1, a forward stable moment Mf2, and a backward stable moment Mb2. FIG. 4A is a diagram for explaining a calculation method of the forward overturning moment Mf1 and the backward stable moment Mb2 when the counterweight unit 120 is rotated backward in accordance with the overturning operation of the boom 104. FIG.

The calculating unit 181 calculates the forward overturning moment Mf1 by the following equation (1).
Mf1 = L11 × WL + Lb1 × WB (1)
As shown in FIG. 4A, WL is a suspended load, which is a value obtained by multiplying the mass of the suspended load 108 by gravitational acceleration. Ll1 is a horizontal distance from the front side overturning fulcrum Of of the crane 100 to the center of gravity Gl of the suspended load. The front-side overturning fulcrum Of is the foremost part of the ground contact surface of the traveling body 101. WB is the weight of the boom 104, and is a value obtained by multiplying the mass of the boom 104 by gravitational acceleration. Lb1 is a horizontal distance from the front-side overturning fulcrum Of of the crane 100 to the center of gravity Gb of the boom 104.

The calculating unit 181 calculates the rear stable moment Mb2 by the following equation (2).
Mb2 = Lm1 × WM + Lc1 × WC (2)
As shown in FIG. 4A, WM is the weight of the crane body, and is a value obtained by multiplying the mass of the crane body by the acceleration of gravity. In this specification, the crane body refers to the structure of the crane 100 excluding the counterweight unit 120 that rotates, the boom 104 that rotates, and the suspended load 108 that is suspended from the boom 104. Lm1 is a horizontal distance from the front side overturning fulcrum Of of the crane 100 to the center of gravity Gm of the crane body. WC is the weight of the counterweight unit 120, and is a value obtained by multiplying the mass of the counterweight unit 120 by gravitational acceleration. Lc1 is a horizontal distance from the front-side overturning fulcrum Of of the crane 100 to the center of gravity Gc of the counterweight unit 120.

  In the storage device of the controller 180, the movement locus information of the center of gravity Gc of the counterweight unit 120 between the first posture and the second posture, that is, the coordinate information of the center of gravity Gc according to the rotation angle of the counterweight unit 120 is stored. It is remembered. The storage device of the controller 180 stores movement trajectory information of the center of gravity Gb of the boom 104 between the minimum angle and the maximum angle of the boom 104, that is, coordinate information of the center of gravity Gb corresponding to the boom angle. The calculation unit 181 calculates the distance Lc1 based on the movement locus information of the center of gravity Gc stored in the storage device, the geometric information of the crane 100, and the rotation angle of the counterweight unit 120 detected by the weight angle sensor 196. Calculate. The computing unit 181 computes the distance Lb1 based on the movement trajectory information of the center of gravity Gb and the geometric information of the crane 100 stored in the storage device, and the undulation angle of the boom 104 detected by the boom angle sensor 194. The computing unit 181 computes the distance Ll1 based on the geometric information of the crane 100 stored in the storage device and the undulation angle of the boom 104 detected by the boom angle sensor 194. The distance Lm1 is one piece of geometric information of the crane 100 stored in the controller 180 in advance.

  The rotation control unit 182 shown in FIG. 3 controls the weight rotation device 130 based on the front overturning moment Mf1 and the rear stability moment Mb2, and the counterweight unit is arranged so that the center of gravity of the entire crane is located at the center in the front-rear direction. 120 is rotated. The rotation control unit 182 calculates the ratio of the forward overturning moment Mf1 to the backward stable moment Mb2, that is, the moment ratio Mf1 / Mb2. The rotation control unit 182 determines that the backward rotation condition is satisfied when the moment ratio Mf1 / Mb2 is equal to or greater than a preset threshold value α. Note that Mf1 and Mb2 are positive values. The threshold value α is a value less than 1 (for example, a value in the range of 0.6 to 0.8), is set to prevent the crane 100 from tipping forward, and is stored in advance in the storage device. .

  When the backward rotation condition is satisfied, the rotation control unit 182 rotates the hydraulic motor of the weight rotation device 130 and rotates the counterweight unit 120 backward by a predetermined angle. The rotation control unit 182 rotates the counterweight unit 120 backward by a predetermined angle, stops the rotation of the counterweight unit 120, and holds the counterweight unit 120 at the position.

  FIG. 4B is a diagram for explaining a calculation method of the backward tipping moment Mb1 and the forward stable moment Mf2 when the counterweight unit 120 is rotated forward according to the standing operation of the boom 104.

The calculating unit 181 calculates the backward tipping moment Mb1 by the following equation (3).
Mb1 = Lc2 × WC (3)
As shown in FIG. 4B, Lc2 is a horizontal distance from the rear side falling fulcrum Ob of the crane 100 to the center of gravity Gc of the counterweight unit 120. The rear side falling fulcrum Ob is the last part of the ground contact surface of the traveling body 101.

The calculating unit 181 calculates the forward stable moment Mf2 by the following equation (4).
Mf2 = Lm2 × WM + Lb2 × WB + Ll2 × WL (4)
As shown in FIG. 4 (b), Lm2 is a horizontal distance from the rear fall fulcrum Ob of the crane 100 to the center of gravity Gm of the crane body. Lb <b> 2 is a horizontal distance from the rear side falling fulcrum Ob of the crane 100 to the center of gravity Gb of the boom 104. L12 is a horizontal distance from the rear side falling fulcrum Ob of the crane 100 to the center of gravity Gl of the suspended load.

  The calculation unit 181 calculates the distance Lc2 based on the movement locus information of the center of gravity Gc stored in the storage device, the geometric information of the crane 100, and the rotation angle of the counterweight unit 120 detected by the weight angle sensor 196. Calculate. The computing unit 181 computes the distance Lb2 based on the movement locus information of the center of gravity Gb and the geometric information of the crane 100 stored in the storage device, and the undulation angle of the boom 104 detected by the boom angle sensor 194. The computing unit 181 computes the distance L12 based on the geometric information of the crane 100 stored in the storage device and the boom 104 undulation angle detected by the boom angle sensor 194. The distance Lm2 is one piece of geometric information stored in the controller 180 in advance.

  The rotation control unit 182 shown in FIG. 3 controls the weight rotation device 130 based on the backward tipping moment Mb1 and the forward stability moment Mf2, and the counterweight unit is arranged so that the center of gravity of the entire crane is located in the center in the front-rear direction. 120 is rotated. The rotation control unit 182 calculates the ratio of the rearward fall moment Mb1 to the forward stable moment Mf2, that is, the moment ratio Mb1 / Mf2. The rotation control unit 182 determines that the forward rotation condition is satisfied when the moment ratio Mb1 / Mf2 is equal to or greater than a preset threshold value β. Note that Mb1 and Mf2 are positive values. The threshold value β is a value less than 1 (for example, a value in the range of 0.6 to 0.8), is set to prevent the crane 100 from falling backward, and is stored in the storage device in advance. .

  When the forward rotation condition is satisfied, the rotation control unit 182 rotates the hydraulic motor of the weight rotation device 130 and rotates the counterweight unit 120 forward by a predetermined angle. The rotation control unit 182 rotates the counterweight unit 120 forward by a predetermined angle, stops the rotation of the counterweight unit 120, and holds the counterweight unit 120 at that position.

  FIG. 5 is a flowchart showing the processing contents of the rotation control by the controller according to the first embodiment. The process shown in this flowchart is started, for example, by turning on an ignition switch (not shown), and is repeatedly executed at a predetermined control cycle after initial setting (not shown) is performed. Basic information such as the length of the boom 104 and the size of the hook 107 is registered in advance by operating the input device 195 by the operator.

  In step S110, the controller 180 acquires various types of information detected by sensors such as the boom angle sensor 194, the load meter 193, and the weight angle sensor 196, and proceeds to step S120. In step S120, the controller 180 calculates moments Mf1, Mf2, Mb1, and Mb2 based on the information acquired in step S110, and proceeds to step S130.

  In step S130, the controller 180 determines whether or not the moment ratio Mf1 / Mb2 is greater than or equal to the threshold value α. If an affirmative determination is made in step S130, the process proceeds to step S140. If a negative determination is made in step S130, the process proceeds to step S135.

  In step S135, the controller 180 determines whether or not the moment ratio Mb1 / Mf2 is greater than or equal to the threshold value β. If a positive determination is made in step S135, the process proceeds to step S145, and if a negative determination is made in step S135, the process returns to step S110.

  In step S140, the controller 180 rotates the counterweight unit 120 backward by a predetermined angle, and returns to step S110. In step S145, the controller 180 rotates the counterweight forward by a predetermined angle and returns to step S110.

  The operation of the present embodiment is summarized as follows. The operator operates the operation device 191 to cause the boom 104 to fall. When the boom 104 falls down and the forward falling moment Mf1 increases, the backward rotation condition is satisfied, and the counterweight unit 120 rotates backward. As a result, the rear stability moment Mb2 is increased, and the stability of the crane is improved.

  The operator operates the operation device 191 to raise the boom 104. When the boom 104 stands up and the forward stability moment Mf2 decreases, the forward rotation condition is satisfied, and the counterweight unit 120 rotates forward. Thereby, the backward falling moment Mb1 is reduced and the stability of the crane is improved.

  In the present embodiment, the weight rotation device 130 can shift the counterweight unit 120 downward from the second posture to shift to the third posture, which is a posture for placing the counterweight unit 120 on the ground. A method for attaching and detaching the counterweight unit 120 will be described. FIG. 6 is a diagram for explaining a method for attaching and detaching the counterweight unit. The counterweight unit 120 is removed from the base 140 as follows.

  A detachment mode switch is disposed in the cab, and when the operator turns on the detachment mode switch, the controller 180 sets the detachment mode. When the attachment / detachment mode is set, the controller 180 controls the display device 192 to display a display image representing an instruction to cause the boom 104 to fall on the display screen of the display device 192. When the operator falls the boom 104, the counterweight unit 120 rotates backward. When the boom 104 is laid down to a predetermined angle, the counterweight unit 120 assumes the second posture.

  The controller 180 determines from the information detected by the weight angle sensor 196 whether or not the counterweight unit 120 is in the second posture position. When it is determined that the counterweight unit 120 is in the position of the second posture, the controller 180 further rotates the counterweight unit 120 90 degrees counterclockwise as shown in FIG. The weight unit 120 is placed on the ground. If a gap is formed between the ground and the weight 111 or the like, a plate material or the like that fills the gap is disposed.

  The controller 180 determines from the information detected by the weight angle sensor 196 whether or not the counterweight unit 120 is in the third posture. When it is determined that the posture is the third posture, the controller 180 controls the display device 192 to display a display image indicating that the rotary shaft 131 is removable on the display screen of the display device 192.

  The operator releases the connection between the rotary shaft 131 and the output shaft of the hydraulic motor, and removes the rotary shaft 131 using a jig or the like. After removing the rotating shaft 131, the operator operates the traveling operating device to drive the traveling body 101 and move the crane 100 forward. Thereby, the counterweight unit 120 is removed from the base 140. Note that the procedure for attaching the counterweight unit 120 to the base 140 is the reverse of the procedure for removing the counterweight unit 120 from the base 140, and thus the description thereof is omitted. Since the output shaft of the hydraulic motor, which is the mounting portion of the base 140, and the coupling portion, which is the mounting portion of the counterweight unit 120, are substantially the same height from the ground, positioning work during the mounting operation can be easily performed. It can be carried out.

According to the embodiment described above, the following operational effects can be obtained.
(1) The crane 100 includes a traveling body 101, a revolving body 103 provided on the upper portion of the traveling body 101 so as to be capable of turning, and a boom 104 provided on the revolving body 103 so as to be raised and lowered. The crane 100 is provided with a counterweight device 110 to prevent the crane from overturning during work. The counterweight device 110 includes a counterweight unit 120 disposed at the rear portion of the crane 100 and a weight rotating device 130 that rotates the counterweight unit 120 in a vertical plane. Since the counterweight unit 120 can be rotated, for example, when the suspension load is small, the counterweight unit 120 is positioned in the first posture on the front side to stabilize the crane, and when the suspension load is large, the counterweight unit 120 is moved to the rear side. The suspension performance can be improved by being positioned in the second posture. Since the counter weight unit 120 is rotated at the rear portion of the crane 100 and the center of gravity of the counter weight unit 120 is moved only in the longitudinal direction of the crane 100 to control the moment, the lateral width of the crane 100 is increased. Can be prevented.

(2) The weight rotating device 130 is configured to be able to rotate the counterweight unit 120 to the third posture in which the counterweight unit 120 is placed on the ground. Since the weight rotating device 130 for improving the suspension performance of the crane has a function as a self-removing device for the counterweight unit 120, it is not necessary to provide a dedicated self-removing device, and the number of parts and cost are reduced. be able to.

(3) The controller 180 calculates the overturning moments Mf1, Mb1 and the stable moments Mf2, Mb2 of the crane 100, and the weight rotating device 130 based on the overturning moments Mf1, Mb1, and the stable moments Mf2, Mb2. It has a rotation control unit 182 that controls and rotates the counterweight unit 120. Based on the operation of the boom 104, the counterweight unit 120 is rotated and the moment is controlled, so that the stability of the crane 100 in operation can be ensured.

-Second Embodiment-
A crane 200 according to the second embodiment will be described with reference to FIGS. In the figure, the same reference numerals are assigned to the same or corresponding parts as those in the first embodiment, and the differences will be mainly described. FIG. 7 is a diagram for explaining the sliding mechanism and the sliding operation of the counterweight unit. In the first embodiment, the example in which the plurality of weights 111 are coupled to the weight support frame 112 by the bolts 119 has been described (see FIG. 2). On the other hand, in 2nd Embodiment, the weights adjacent to the lamination direction are connected by the hydraulic cylinder.

  In the second embodiment, a weight moving device 260 that moves at least one of the plurality of weights 211 stacked in the vertical direction on the weight support frame 112 with respect to the other weights 211 is provided. . The weight moving device 260 includes a control valve that controls the flow of the pressure oil discharged from the above-described hydraulic pump, and a plurality of hydraulic cylinders 222 that are driven by the pressure oil supplied through the control valve. Yes. In the present embodiment, when the control valve is opened, pressure oil is supplied to all of the plurality of hydraulic cylinders 222 in the same manner.

  As shown in FIG. 7, the hydraulic cylinder 222 constituting the weight moving device 260 is provided between the weights 211 adjacent to each other in the stacking direction and the vertical (vertical) direction in the second posture. For convenience of explanation, the lowermost weight 211 is defined as the lower weight 211L, the uppermost weight 211 is defined as the upper weight 211U, and the weight 211 between the upper weight 211U and the lower weight 211L is defined as the intermediate weight 211M. .

  The lower weight 211L has a rectangular parallelepiped lower concave portion 213 extending in the front-rear direction and having an upper surface open at the top and recessed downward. The dimension between the front surface and the rear surface of the lower recess 213 is longer than the longitudinal dimension of the hydraulic cylinder 222 in the most extended state. The intermediate weight 211M is provided with a rectangular parallelepiped upper concave portion 214 having a lower surface and a front surface open at the bottom and recessed upward. The intermediate weight 211M is provided with a lower recess 213 similar to the lower weight 211L. The upper weight 211U is provided with an upper concave portion 214 similar to the intermediate weight 211M.

  In the second posture, the lower recess 213 and the upper recess 214 are arranged to face each other, and the accommodation space for the hydraulic cylinder 222 is defined by the lower recess 213 and the upper recess 214. The hydraulic cylinder 222 is fixed to the front surface of the lower concave portion 213 of the weight 211 whose lower end is located at the end of the cylinder tube, and the upper end of the weight 211 whose upper end is located at the end of the piston rod. It is fixed to the rear surface of the recess 214.

  FIG. 8 is a diagram similar to FIG. 3 and is a block diagram for explaining the slide movement control of the counterweight unit in the crane according to the second embodiment. A stroke sensor 297 that detects the stroke of the hydraulic cylinder 222 and outputs the detected stroke signal to the controller 280 is connected to the controller 280 according to the second embodiment. The controller 280 functionally includes a slide movement control unit 283 in addition to the functions described in the first embodiment.

  In addition to the calculation process described in the first embodiment, the calculation unit 281 is based on the stroke of the hydraulic cylinder 222 detected by the stroke sensor 297 and the geometric information of the crane 200, and the center of gravity Gc of the counterweight unit 220 and the front side A distance Lc1 between the overturning fulcrum Of and a distance Lc2 between the center of gravity Gc of the counterweight unit 220 and the rear side overturning fulcrum Ob is calculated. The storage device of the controller 280 stores in advance the relationship between the stroke of the hydraulic cylinder 222 and the amount of movement of the center of gravity Gc.

  The slide movement control unit 283 determines whether or not the counterweight unit 220 is in the second posture position based on the angle detected by the weight angle sensor 196. In a state where it is determined that the counterweight unit 220 is in the position of the second posture, if the moment ratio Mf1 / Mb2 is equal to or greater than a preset threshold value α, it is determined that the rear slide condition is satisfied.

  As shown in FIG. 7B, when the rear slide condition is satisfied, the slide movement control unit 283 extends each hydraulic cylinder 222 of the weight moving device 260 so that the intermediate weight 211M is moved from the lower weight 211L by a predetermined distance. The upper weight 211U is moved backward with respect to the intermediate weight 211M by a predetermined distance. The slide movement control unit 283 slides the weight 211 backward, stops the slide movement of the counterweight unit 220, and holds the counterweight unit 220 at that position.

  When it is determined that the counterweight unit 220 is in the position of the second posture and the counterweight unit 220 is stepped, the moment ratio Mb1 / Mf2 is greater than or equal to a preset threshold value β. It is determined that the slide condition is satisfied. The slide movement control unit 283 determines that the counterweight unit 220 is not stepped when the stroke detected by the stroke sensor 297 is less than the threshold value x, and the counterweight unit 220 when the stroke is greater than or equal to the threshold value x. Is determined to be stepped. The threshold value x is a threshold value for determining that the stroke is almost zero, and is stored in the storage device of the controller 280 in advance.

  When the forward slide condition is satisfied, the slide movement control unit 283 contracts each hydraulic cylinder 222 of the weight moving device 260, moves the intermediate weight 211M forward with respect to the lower weight 211L by a predetermined distance, and only by the predetermined distance. The upper weight 211U is moved forward with respect to the intermediate weight 211M. The slide movement control unit 283 slides the weight 211 forward, stops the slide movement of the counterweight unit 220, and holds the counterweight unit 220 at that position.

  FIG. 9 is a flowchart showing the processing content of the slide movement control by the controller 280 according to the second embodiment. The process shown in this flowchart is started, for example, by turning on an ignition switch (not shown), and is repeatedly executed at a predetermined control cycle after initial setting (not shown) is performed. Basic information such as the length of the boom 104 and the size of the hook 107 is registered in advance by operating the input device 195 by the operator.

  In step S210, the controller 280 acquires various information detected by sensors such as the boom angle sensor 194, the load meter 193, the weight angle sensor 196, and the stroke sensor 297, and the process proceeds to step S215.

  In step S215, the controller 280 determines whether or not the counterweight unit 220 is in the second posture based on the angle of the counterweight unit 220 acquired in step S210. If a positive determination is made in step S215, the process proceeds to step S220, and if a negative determination is made in step S215, the process returns to step S210.

  Step S220 is the same moment calculation process as step S120 of FIG. When the moment calculation process in step S220 is completed, the process proceeds to step S230. Step S230 is the same process as step S130 of FIG. 5, and the controller 280 determines whether or not the moment ratio Mf1 / Mb2 is equal to or greater than the threshold value α. If an affirmative determination is made in step S230, the process proceeds to step S240, and if a negative determination is made in step S230, the process proceeds to step S235.

  Step S235 is the same process as step S135 of FIG. 5, and the controller 280 determines whether or not the moment ratio Mb1 / Mf2 is equal to or greater than the threshold value β. If an affirmative determination is made in step S235, the process proceeds to step S238, and if a negative determination is made in step S235, the process returns to step S210.

  In step S238, the controller 280 determines whether or not the counterweight unit 220 is stepped based on the stroke information acquired in step S210. If an affirmative determination is made in step S238, the process proceeds to step S245, and if a negative determination is made in step S238, the process returns to step S210.

  In step S240, the controller 280 slides the upper weight 211U and the intermediate weight 211M constituting the counterweight unit 220 backward by a predetermined distance with respect to the lower weight 211, and returns to step S210. In step S245, the controller 280 slides the upper weight 211U and the intermediate weight 211M constituting the counterweight unit 220 forward by a predetermined distance with respect to the lower weight 211, and returns to step S210.

According to such 2nd Embodiment, in addition to the effect demonstrated in 1st Embodiment, there exists the following effect.
(4) In the second posture, the moment can be controlled by further moving the center of gravity of the counterweight unit 220 in the front-rear direction, so that the suspension performance can be further improved.

(5) The controller 280 controls the weight moving device 260 based on the overturning moments Mf1, Mb1, and the stable moments Mf2, Mb2, and the calculation unit 281 that calculates the overturning moments Mf1, Mb1 and the stable moments Mf2, Mb2 of the crane 200. In addition, a slide movement control unit 283 that moves at least one of the plurality of weights 211 in the horizontal direction with respect to the other weights 211 is provided. Thereby, the stability of the crane 100 under operation can be ensured by sliding the counterweight unit 120 based on the operation of the boom 104 and controlling the moment.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(Modification 1)
In the first embodiment, the example in which the counterweight unit 120 is rotated by the hydraulic motor has been described. However, the present invention is not limited to this. The counterweight unit 120 may be rotated by a rotation device that is a combination of a hydraulic cylinder and a link mechanism.

(Modification 2)
In the second embodiment, the example in which all the hydraulic cylinders 222 are stroked at the same time has been described, but the present invention is not limited to this. The hydraulic cylinder 222 may be driven in order from top to bottom or from bottom to top.

(Modification 3)
The number and shape of the weights 111 and 211 and the structure of the weight support frame 112 are not limited to the example described in the above embodiment. Various means can be adopted as the means for supporting the weights 111 and 211.

(Modification 4)
In the above-described embodiment, the controllers 180 and 280 are configured to use the counterweight device so as to increase the rearward stability moment according to the increase in the forward fall moment and to decrease the rearward fall moment according to the decrease in the forward stability moment. Although the example which controls operation | movement of 110,210 was demonstrated, this invention is not limited to this. For example, the counterweight unit 120 may be operated so as to shift to one of the first posture, the second posture, and the third posture according to the length of the boom 104 to be attached.

  Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Crane, 101 traveling body, 103 revolving body, 104 boom, 110 counterweight device, 111 weight, 112 weight support frame (support structure), 120 counterweight unit, 130 weight rotation device (rotation device), 180 controller (Control device), 181 calculation unit, 182 rotation control unit, 200 crane, 211 weight, 220 counterweight unit, 260 weight movement device, 280 controller (control device), 281 calculation unit, 283 slide movement control unit (movement control) Part)

Claims (5)

In a crane provided with a traveling body, a revolving body provided on the upper portion of the traveling body so as to be able to swivel, and a boom provided on the revolving body,
A counterweight unit disposed at the rear of the crane;
A crane that rotates the counterweight unit in a vertical plane. The crane according to claim 1,
The said rotation apparatus is comprised so that rotation of the said counterweight unit is possible to the attitude | position which mounts the said counterweight unit on the ground. The crane according to claim 1,
The counterweight unit has a plurality of weights and a support structure that supports the plurality of weights,
A crane comprising: a moving device that moves at least one of the plurality of weights stacked in the vertical direction on the support structure in a horizontal direction with respect to other weights. The crane according to claim 1,
A control unit having a calculation unit that calculates the overturning moment and the stable moment of the crane, and a rotation control unit that controls the rotating device based on the overturning moment and the stable moment and rotates the counterweight unit. A crane characterized by comprising: The crane according to claim 3,
An arithmetic unit that calculates the overturning moment and the stable moment of the crane, and the moving device is controlled based on the overturning moment and the stable moment, and at least one of the plurality of weights is horizontal with respect to other weights. A crane comprising a control device having a movement control unit for moving in a direction.

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