WO2019050069A1

WO2019050069A1 - Construction machine

Info

Publication number: WO2019050069A1
Application number: PCT/KR2017/009896
Authority: WO
Inventors: Yunhwan CHOI; Changhoon Lee
Original assignee: Volvo Construction Equipment Ab
Priority date: 2017-09-08
Filing date: 2017-09-08
Publication date: 2019-03-14

Abstract

A construction machine, the center of gravity of which can be moved in an opposite direction when the center of gravity is offset forwardly or rearwardly depending on a situation, thereby maintaining balance and ensuring positional stability. A working device is disposed on a front portion of a frame. A counterweight has a bottom end coupled to a rear portion of the frame using a pin. The counterweight pivots about the pin and is fixed in a position in which pivoting of the counterweight is completed. A pivot control module is connected between the frame and the counterweight to cause the counterweight to pivot in a first direction, or a second direction, opposite to the first direction. A controller is electrically connected to the pivot control module to move a center of gravity of the construction machine by operating the pivot control module.

Description

CONSTRUCTION MACHINE

The present disclosure relates to a construction machine and, more particularly, to a construction machine in which the center of gravity can be moved in an opposite direction when the center of gravity is offset forwardly or rearwardly depending on a situation, thereby maintaining balance and ensuring positional stability.

In general, a construction machine, for example, an excavator, commonly performs work in the environment having poor working conditions, for example, on a slope or on weak ground. In addition, objects to be worked by an excavator are commonly heavy, and a working device, including a boom, an arm, and a bucket, mounted on the excavator is also heavy. Since the working device is mounted on the body of the excavator while protruding forwardly of the excavator body, the excavator is commonly provided with a counterweight to balance the working device. While the working device is disposed on the front portion of the excavator, the counterweight is disposed on the rear portion of the excavator. The counterweight is a balancing weight configured to balance the weight of the excavator body or equalize external force acting on the excavator body.

Since the working device protrudes forwardly of the excavator body and objects to be worked are heavy, as described above, the center of gravity of the excavator is commonly offset forwardly during work. Thus, the positional stability of the excavator may be reduced. To prevent this, a relatively large and heavy counterweight is required. However, the larger the counterweight is, the lower the fuel efficiency of the excavator is, due to the increased weight. In addition, when the counterweight is larger, it may be difficult to operate the excavator in a limited space, so that working efficiency may also be reduced.

Accordingly, the present disclosure has been made in consideration of the above-described problems occurring in the related art, and the present disclosure proposes a construction machine that can move a center of gravity in an opposite direction when the center of gravity is offset forwardly or rearwardly depending on a situation, thereby maintaining balance and ensuring positional stability.

According to an aspect of the present disclosure, a construction machine may include: a frame, on a front portion of which a working device is disposed; a counterweight having a bottom end coupled to a rear portion of the frame using a pin, wherein the counterweight pivots about the pin and is fixed in a position in which pivoting of the counterweight is completed; a pivot control module connected between the frame and the counterweight to cause the counterweight to pivot in a first direction, or a second direction, opposite to the first direction; and a controller electrically connected to the pivot control module to move a center of gravity of the construction machine by operating the pivot control module.

The pivot control module may be provided on both sides of the frame in a width direction and on both sides of the counterweight in a width direction. The front portion and the rear portion may be categorized based on a direction in which the construction machine travels, and the width direction may be perpendicular to the direction in which the construction machine travels.

The pivot control module may include: a wire connecting the rear portion of the frame and the counterweight; a winder disposed on the frame and connected to the wire, the winder being rotatable about an axis thereof to wind or unwind the wire to allow the counterweight to pivot; and a guide disposed on a path along which the wire moves to guide the movement of the wire.

The wire may hold the counterweight to be fixed in the position in which the pivoting of the counterweight is completed.

The counterweight may include a hook configured to catch one end of the wire.

The pivot control module may further include a holding link member having one and the other longitudinal ends connected to the winder and the counterweight, respectively. The holding link member may pivot in response to an operation of the winder to push the counterweight to pivot and, after the counterweight has pivoted in the first direction, may prevent the counterweight from pivoting in the second direction.

The control module may further include a gear train connecting the winder and the holding link member such that the holding link member pivots in concert with the operation of the winder.

The gear train may include: a first gear disposed on a rotary shaft of the winder; a second gear disposed on a longitudinal end of the holding link member to be rotated by the first gear; and a third gear disposed between the first gear and the second gear to allow the second gear to rotate in the same direction as the first gear.

According to an aspect of the present disclosure, a construction machine may include: a frame, wherein a working device and a cab are disposed on a front portion thereof and an engine room is disposed on a rear portion thereof; a counterweight having a bottom end coupled to a rear portion of the frame using a pin, wherein the counterweight pivots about the pin and is fixed in a position in which pivoting of the counterweight is completed; a first pivot control module connected between the frame and the counterweight to control the counterweight to pivot in a first direction; a second pivot control module connected between the frame and the counterweight to control the counterweight to pivot in a second direction, opposite to the first direction; and a controller electrically connected to the pivot control module to move a center of gravity of the construction machine by operating the pivot control module.

The first pivot control module may be provided on both sides of the frame in a width direction and on both sides of the counterweight in a width direction, and the second pivot control module is provided on both sides of the engine room in a width direction and on both sides of the counterweight in a width direction. The front portion and the rear portion may be categorized based on a direction in which the construction machine travels, and the width direction may be perpendicular to the direction in which the construction machine travels.

The first pivot control module may include: a roller disposed on the frame; and a holding link member having one and the other longitudinal ends connected to the roller and the counterweight, respectively, wherein the holding link member pivots in response to an operation of the roller to push the counterweight to pivot and, after the counterweight has pivoted in the first direction, prevents the counterweight from pivoting in the second direction.

The first control module may further include a gear train connecting the roller and the holding link member such that the holding link member pivots in concert with the operation of the roller.

The gear train may include: a first gear disposed on a rotary shaft of the roller; a second gear disposed on a longitudinal end of the holding link member to be rotated by the first gear; and a third gear disposed between the first gear and the second gear to allow the second gear to rotate in the same direction as the first gear.

The second pivot control module may include: a cylinder disposed outside of the engine room, containing oil therein, and having a piston elastically disposed therein; a first arm having one longitudinal end coupled to the cylinder; a connector connected to the other longitudinal end of the first arm; a second arm having one longitudinal end hinge-coupled to the connector; and a holder disposed on the counterweight, the other longitudinal end of the second arm being coupled to the holder.

The cylinder may be connected to the controller and may be operated by the controller.

According to the present disclosure, the counterweight is coupled to the frame, using a pin, to pivot about the pin and the pivot controller allows the counterweight to pivot. When the center of gravity of the construction machine is offset forwardly or rearwardly, the center of gravity can be moved in the opposite direction by the pivoting of the counterweight, so that balance can be maintained and positional stability can be ensured.

Specifically, according to the present disclosure, the counterweight and the pivot controller are provided as described above. When the center of gravity of the construction machine is offset forwardly, the pivot controller causes the counterweight to pivot in the first direction in which the counterweight is spread rearwardly in the shape of a fan, so that the center of gravity of the construction machine is moved rearwardly. This can consequently maintain the balance of the construction machine, thereby ensuring the positional stability of the construction machine. In addition, according to the present disclosure, when the center of gravity of the construction machine is offset rearwardly, the pivot controller causes the counterweight to pivot in a direction in which the counterweight is folded, i.e. in the second direction, opposite to the first direction, so that the center of gravity is moved forwardly. This can consequently maintain the balance of the construction machine, thereby ensuring the positional stability of the construction machine.

In addition, according to the present disclosure, a relatively large and heavy counterweight of the related art can be substituted by a relatively small and light counterweight that can ensure positional stability, the level of which is the same as or similar to that of the relatively large and heavy counterweight of the related art.

Furthermore, according to the present disclosure, it is unnecessary to equip the construction machine with a relatively large and heavy counterweight, since a relatively small and light counterweight can be used. The construction machine can operate properly in a limited space to improve working efficiency. Since the weight of the construction machine is also reduced, fuel efficiency can also be improved.

FIG. 1 is a side elevation view illustrating a construction machine according to a first exemplary embodiment;

FIGS. 2 and 3 illustrate portions of the construction machine according to the first exemplary embodiment, before and after pivoting of the counterweight; and

FIGS. 4 and 5 illustrate portions of a construction machine according to a second exemplary embodiment, before and after pivoting of the counterweight.

Hereinafter, a construction machine according to exemplary embodiments will be described in detail with reference to the accompanying drawings.

In the following description, detailed descriptions of known functions and components incorporated in the present disclosure will be omitted in the case in which the subject matter of the present disclosure is rendered unclear by the inclusion thereof.

As illustrated in FIG. 1, according to a first exemplary embodiment, a crawler type excavator is illustrated as a construction machine 100. However, this is only illustrative, and the construction machine 100 according to the first exemplary embodiment may be a wheel type excavator or may be a wheel loader, a forklift, or the like. While the crawler type excavator is given as an example of the construction machine 100, in the present disclosure, the construction machine 100 is not limited to being a crawler type excavator.

The construction machine 100 according to the first exemplary embodiment includes a frame 110, a counterweight 120, a pivot control module 130, and a controller 140.

The frame 110 provides a space in which the counterweight 120 and the pivot control module 130 are disposed. That is, the counterweight 120 and the pivot control module 130 are disposed on the frame 110. The frame 110 includes a lower traveling body 111 and an upper swing body 112. The lower traveling body 111 is a crawler type traveling body. However, as described above, the lower traveling body 111 may be a wheel type traveling body.

The upper swing body 112 is mounted on the lower traveling body 111 such that the upper swing body 112 can swing to an intended position in response to the manipulation of an operator. When the upper swing body 112 is comprised of a front portion and a rear portion, with respect to the direction in which the construction machine 100 travels, a working device 10 is disposed on the front portion, and a cab 20 is disposed in parallel with the working device 10. The working device 10 includes a boom 11, an arm 12, and a bucket 13. The components of the working device 10 are respectively actuated by a cylinder corresponding thereto, driven by a hydraulic circuit controlling the flow rate and flow of hydraulic fluid discharged by a hydraulic pump. The hydraulic circuit is operated by pilot signal pressure applied in response to the manipulation of the operator. An engine room 30, the counterweight 120, and the pivot control module 130 are disposed on the rear portion of the upper swing body 112.

The counterweight 120 is a heavy object disposed on the rear portion of the upper swing body 112 to balance the weight of the working device 10 disposed on the front portion of the upper swing body 112, such that the center of gravity of the construction machine 100 is positioned in the rear portion, opposite to the working device 10. Since the counterweight 120 is disposed on the rear portion of the upper swing body 112, as described above, it is possible to ensure the reliability of work and facilitate operations.

The counterweight 120 is coupled to the frame 110, more particularly, to the rear portion of the upper swing body 112 of the frame 110 using a pin. The bottom end of the counterweight 120 being coupled to the rear portion of the upper swing body 112, as described above, means that the counterweight 120 pivots about the pin 121 so that the counterweight 120 is spread rearwardly in the shape of a fan and is then folded. That is, (in the drawings), the counterweight 120 pivots in a clockwise or counterclockwise direction about the pin 121 and is then fixed in a position in which the pivoting is completed.

The counterweight 120 is pivotably provided, as described above, such that, when the center of gravity of the construction machine 100 is offset forwardly or rearwardly depending on a working condition or a situation, the center of gravity can be moved by the pivoting of the counterweight 120, thereby ensuring the positional stability of the construction machine 100.

The pivoting of the counterweight 120 is controlled by the pivot control module 130 connected thereto, and will be described in more detail later. The counterweight 120 includes a hook 122 configured to connect the counterweight 120 to the pivot control module 130. The hook 122 connects the counterweight 120 and the pivot control module 130 by catching one end of a wire 131 that will be described later.

The pivot control module 130 is a device pivoting the counterweight 120. In this regard, the pivot control module 130 is connected between the upper swing body 112 of the frame 110 and the counterweight 120. The pivot control module 130 controls the counterweight 120 to pivot in a first direction, or a second direction, opposite to the first direction. The first direction is a direction in which the front portion of the counterweight 120 facing the rear portion of the upper swing body 112 pivots in the shape of a fan while gradually moving away from the rear portion of the upper swing body 112. The second direction is a direction in which the front portion of the counterweight 120 pivots while gradually moving toward the rear portion of the upper swing body 112. In the drawings, the second direction is a counterclockwise direction. Thus, when the counterweight 120 is controlled by the pivot control module 130 to pivot in the first direction, the center of gravity of the construction machine 100 moves rearwardly. In addition, when the counterweight 120 is controlled by the pivot control module 130 to pivot in the second direction, the center of gravity of the construction machine 100 moves forwardly. For example, when the center of gravity of the construction machine 100 is offset forwardly due to a working environment or the weight of an object to be worked, the pivot control module 130 controls the counterweight 120 to pivot in the first direction, thereby moving the center of gravity of the construction machine 100 rearwardly. This can consequently maintain the balance of the construction machine 100, thereby ensuring positional stability. In contrast, when the center of gravity of the construction machine 100 is offset rearwardly, for example, on a slope, while working in a position swung in the first direction, the pivot control module 130 controls the counterweight 120 to pivot in the second direction, thereby moving the center of gravity of the construction machine 100 rearwardly. This can consequently maintain the balance of the construction machine 100, thereby ensuring positional stability. The pivot control module 130 is operated by the controller 140 manipulated by the operator.

The pivot control module 130 may be provided on both sides of the upper swing body 112 in the width direction and on both sides of the counterweight 120 in the width direction. The width direction refers to a direction perpendicularly intersecting the direction in which the construction machine 100 travels. However, this is only illustrative, and the pivot control module 130 may be provided on one side of the upper swing body 112 in the width direction and on one side of the counterweight 120 in the width direction. In this case, the other sides of the upper swing body 112 and the counterweight 120 in the width direction are required to be configured to support pivoting of the counterweight 120 while working in concert with the operation of the pivot control module 130 provided on one sides of the upper swing body 112 and the counterweight 120.

As illustrated in FIGS. 2 and 3, the pivot control module 130 includes the wire 131 and a winder 132.

The wire 131 is a member connecting the counterweight 120 to the rear portion of the upper swing body 112. During the pivoting of the counterweight 120 in the first direction or second direction, the wire 131 serves to enable the counterweight 120 to rotate while supporting the counterweight 120. When the counterweight 120 finally arrives in@ a position, as illustrated in FIGS. 2 and 3, after having swung, the wire 131 holds the counterweight 120 to be fixed in the position in which the pivoting of the counterweight 120 is completed. In this regard, one end of the wire 131 is connected to the winder 132, while the other end of the wire 131 is fixed to the hook 122 disposed on the counterweight 120.

The winder 132 is disposed on the upper swing body 112 of the frame 110. The winder 132 is connected to one end of the wire 131. The winder 132 may be, for example, a roller, and is operated by the controller 140. The winder 132 rotates about the axis thereof to wind or unwind the wire 131. Since the wire 131 is configured to be wound or unwound by the winder 132, the counterweight 120 supported by the wire 131 can pivot. The wire 131 performs an auxiliary role of allowing the counterweight 120 to pivot in the first direction while being unwound. In contrast, the wire 131 performs a role of directly pivoting the counterweight 120 in the second direction while being wound.

The pivot control module 130 further includes a guide 133. As illustrated in FIGS. 2 and 3, the guide 133 is disposed on a path along which the wire 131 moves to guide the movement of the wire 131, i.e. the redirection of the wire 131. The guide 133 may be, for example, a pulley.

The pivot control module 130 further includes a holding link member 134 and a gear train 135 to mechanically pivot the counterweight 120 in the first direction.

One and the other longitudinal ends of the holding link member 134 are connected to the winder 132 and the counterweight 120, respectively. The holding link member 134 pivots in the shape of a fan, in response to the operation of the winder 132. When the holding link member 134 pivots, the counterweight 120 connected to the holding link member 134 pivots in the first direction, due to force applied by the holding link member 134. When the counterweight 120 has pivoted in the first direction, the holding link member 134 prevents the counterweight 120 pivoting in the second direction. Specifically, after the counterweight 120 has pivoted in the first direction, further pivoting in the first direction is prevented by the wire 131, and reverse pivoting in the second direction is also prevented by the holding link member 134.

The gear train 135 is disposed between the winder 132 and the holding link member 134 and connects the winder 132 and the holding link member 134 such that the holding link member 134 pivots in concert with the operation of the winder 132. The gear train 135 includes a first gear 136 and a second gear 136.

The first gear 136 is a driving gear disposed on a rotary shaft of the winder 132. Following the rotation of the winder 132, the first gear 136 rotates in the same direction as the winder 132, i.e. in the first direction or the second direction. The second gear 137 is a driven gear connected to the first gear 136 to be rotated by the first gear 135. The second gear 137 is disposed on one longitudinal end of the holding link member 134.

The gear train 135 further includes a third gear 138. The third gear 138 is a transfer gear allowing the second gear 137 to rotate in the same direction as the first gear 136. In this regard, the third gear 138 is disposed between the first gear 136 and the second gear 136.

For example, when the winder 132 rotates in the first direction, the first gear 136 connected to the rotary shaft of the winder 132 rotates in the same direction. This rotates the third gear 138 in the second direction, thereby rotating the second gear 137 in the first direction. As the second gear 137 rotates in the first direction, the holding link member 134 pivots about the second gear 137 in the first direction, in the shape of a fan. Then, the counterweight 120 pivots in the first direction, due to force applied by the holding link member 134. Consequently, the counterweight 120 is spread in the shape of a fan from the initially mounted position, so that the center of gravity of the construction machine 100 is moved rearwardly. In contrast, when the winder 132 rotates in the second direction, the first gear 136 connected to the rotary shaft of the winder 132 rotates in the same direction, i.e. the second direction. This rotates the third gear 138 in the first direction, thereby rotating the second gear 137 in the second direction. As the second gear 137 rotates in the second direction, the holding link member 134 pivots about the second gear 137 in the second direction, in the shape of a fan. At the same time, as the winder 132 rotates in the second direction, the wire 131 is wound to pivot the counterweight 120 in the second direction, thereby returning the counterweight 120 to the initially mounted position. Consequently, the center of gravity of construction machine 100 is moved forwardly. When the wire 131 draws the counterweight 120 while being wound, the holding link member 134 also pivots in the second direction, so that the holding link member 134 does not interfere with the counterweight 120.

The gear train 135 may include a reduction gear to control the angle of rotation of the holding link member 134 at around a predetermined angle, for example, 90°. In this regard, the first gear 136 has a higher gear ratio than the second gear 137. For example, the diameter of the first gear 136 is smaller than the diameter of the second gear 137. When the gear ratio of the first gear 136 is higher than the gear ratio of the second gear 137, even in the case in which the winder 132 winding or unwinding the wire 131 is rotated a plurality of times to pivot the counterweight 120 to a predetermined position and the first gear 136 is responsively rotated a plurality of times, the second gear 137 only rotates to a predetermined angle, thereby allowing the holding link member 134 connected thereto to pivot to a predetermined angle. Consequently, the counterweight 120 can be pivoted to the predetermined position. The gear ratios of the first gear 136 and the second gear 137 may be calculated in consideration of the number of revolutions of the winder 132, depending on the winding or unwinding length of the wire 131, as well as the angle of pivot of the holding link member 134.

The controller 140 is electrically connected to the pivot control module 130. More specifically, the controller 140 is electrically connected to the winder 132 of the pivot control module 130 to operate the winder 132. In this regard, the controller 140 is operated by the manipulation of the operator and, upon receiving an instruction signal from the operator, controls the center of gravity of the construction machine 100 to move by rotating the winder 132 in the first direction or the second direction.

Hereinafter, the operation of the construction machine according to the first exemplary embodiment will be described with reference to FIGS. 2 and 3.

The construction machine 100 according to the first exemplary embodiment may be switched among a first mode, a second mode, and a third mode, in response to pivoting of the counterweight 120.

First, as illustrated in FIG. 2, the first mode indicates a position of the counterweight 120 before pivoting, i.e. an initially mounted position.

Second, as illustrated in FIG. 3, the second mode indicates a position to which the counterweight 120 has pivoted in the first direction from the position of the first mode. In the first mode of the construction machine 100, when the center of gravity of the construction machine 100 is offset forwardly, the operator may rotate the winder 132 in the first direction by manipulating the controller 140, so that the gear train 135 connected to the winder 132 rotates. Consequently, the holding link member 134 pivots in the first direction, there by mechanically pivoting the counterweight 120 in the first direction. At the same time, the wire 131 is unwound following the rotation of the winder 132 in the first direction, thereby allowing the counterweight 120 to be pivotable.

When the counterweight 120 pivots in the first direction to be in the spread position, the center of gravity of the construction machine 100 that has been offset forwardly is moved rearwardly. Then, the construction machine 100 can maintain balance, thereby ensuring positional stability. When the pivoting of the counterweight 120 to a specific position is completed, the operation of the winder 132 is stopped, thereby stopping both the unwinding of the wire 131 and the pivoting of the holding link member 134. Consequently, the counterweight 120 that has pivoted in the first direction remains in a firmly fixed position, since further pivoting in the first direction is prevented by the wire 131, the unwinding of which is stopped, and reverse pivoting in the second direction is also prevented by the holding link member 134, the pivoting of which is stopped.

Next, the third mode indicates a position to which the counterweight 120 has pivoted in the second direction from the position of the second mode. The finally pivoted position of the counterweight 120 in the third mode is the same as the initially mounted position of the counterweight 120 in the first mode.

Specifically, in the second mode of the construction machine 100, when the center of gravity of the construction machine 100 is offset rearwardly, due to a working environment, the operator may rotate the winder 132 in the second direction by manipulating the controller 140, so that the gear train 135 connected to the winder 132 rotates, allowing the holding link member 134 to pivot in the second direction. At the same time, the wire 131, connecting the winder 132 and the counterweight 120, is wound to draw the counterweight 120, thereby pivoting the counterweight 120 in the second direction. When the counterweight 120 returns to the initially mounted position by pivoting in the second direction, the center of gravity of the construction machine 100 that has been offset rearwardly is moved forwardly. Consequently, the construction machine 100 can maintain balance, thereby ensuring positional stability. When the counterweight 120 pivoting in the second direction comes into contact with outer surfaces of the engine room 30 and the upper swing body 112, the counterweight 120 remains in a firmly fixed position, since further pivoting in the second direction is prevented by the engine room 30 and the upper swing body 112 and reverse pivoting in the first direction is prevented by the wire 131 that is completely wound. In addition, when the wire 131 draws the counterweight 120 while being wound, the holding link member 134 also pivots in the second direction, so that the holding link member 134 does not interfere with the counterweight 120, thereby allowing the counterweight 120 to pivot smoothly.

As set forth above, the construction machine 100 according to the first exemplary embodiment can move the center of gravity thereof by pivoting the counterweight 120 using the pivot control module 130. Thus, even in the case in which a heavy counterweight having a relatively-large size of the related art is substituted by a relatively small and light counterweight, a level of positional stability the same as or similar to that of the relatively large and heavy counterweight can be ensured. In addition, since a relatively small and light counterweight can be used, the construction machine 100 can operate properly in a limited space to improve working efficiency. Since the overall weight of the construction machine 100 is reduced to the reduced size of the counterweight 120, fuel efficiency can also be improved.

Hereinafter, a construction machine according to a second exemplary embodiment will be described with reference to FIGS. 4 and 5.

FIGS. 4 and 5 illustrate portions of the construction machine according to the second exemplary embodiment, before and after pivoting of the counterweight.

As illustrated in FIGS. 4 and 5, construction machine 100 according to the second exemplary embodiment includes a frame 110, a counterweight 120, a first pivot control module 130, a second pivot control module 230, and a controller 140.

The second exemplary embodiment is substantially the same as the first exemplary embodiment, except that the pivot control module is comprised of the first pivot control module and the second pivot control module. The same components will be denoted by the same reference numerals and detailed descriptions thereof will be omitted.

The first pivot control module 130 is connected between the frame 110 and the counterweight 120 to control the counterweight 120 to pivot in a first direction. The first pivot control module 130 includes a roller 132, a holding link member 134, and a gear train 135. The first pivot control module 130 according to the second exemplary embodiment is not provided with the wire (131 in FIG. 2) unlike the first exemplary embodiment. Thus, the winder (132 in FIG. 2), according to the first exemplary embodiment, is referred to as a roller 132 without a winding function, according to the second exemplary embodiment. In addition, descriptions of the holding link member 134 and the gear train 135 will be omitted, since they are the same as those of the first exemplary embodiment.

The second pivot control module 230 is connected between the engine room 30 and the counterweight 120. The second pivot control module 230 controls the counterweight 120 to pivot in a second direction. The second pivot control module 230 includes a cylinder 231, a holder 232, a connector 233, a first arm 234, and a second arm 234. The cylinder 231 is disposed outside of the engine room 30. One longitudinal end of the first arm 234 is coupled to the cylinder 231, and the other longitudinal end of the first arm 234 is coupled to the connector 233. One longitudinal end of the second arm 234 is hinge-coupled to the connector 233, and the other longitudinal end of the second arm 234 is coupled to the holder 232 disposed on the counterweight 120.

The cylinder 231 contains oil therein, and has a piston elastically disposed therein. The cylinder 231 moves the first arm 234 and the second arm 235 connected to the first arm 234 in the second direction, in response to an operation of the elastically-disposed piston and a hydraulic action of fluid circulating within the cylinder 231, thereby gradually pivoting the counterweight 120. In this case, elastic restoring force is applied to the piston. Since the counterweight 120 is a heavyweight object, it may be difficult to pivot the counterweight 120 in the second direction, i.e. in the direction in which the counterweight 120 is folded, using only elastic restoring force. In this regard, the cylinder 231 is connected to the controller 140 such that the cylinder 231 is operated by the controller 140. In addition to elastic restoring force, the piston of the cylinder 231 can be actuated by additional power, such as hydraulic pressure, mechanical energy, or electricity, applied by the controller 140.

When the first pivot control module 130 pivots the counterweight 120 in the first direction, the piston of the cylinder 231 is elastically deformed by force transferred via the second arm 235 and the first arm 234, thereby allowing the first arm 234 and the second arm 235 to move. Thus, the counterweight 120 can smoothly pivot in the first direction.

Hereinafter, the operation of the construction machine according to the second exemplary embodiment will be described with reference to FIGS. 4 and 5.

The construction machine according to the second exemplary embodiment can switch among a first mode, a second mode, and a third mode, in response to the pivoting of the counterweight 120.

First, as illustrated in FIG. 4, the first mode indicates a position before the counterweight 120 pivots, i.e. an initially mounted position.

As illustrated in FIG. 5, the second mode indicates a position in which the counterweight 120 has pivoted in the first direction from the first mode. In the case in which the center of gravity of the construction machine in the first mode is offset forwardly due to the working environment, when the operator rotates the roller 132 in the first direction by manipulating the controller 140, the gear unit 135 connected to the roller 132 rotates, so that the holding link member 134 responsively pivots in the first direction, thereby mechanically pivoting the counterweight 120 in the first direction. When the counterweight 120 reaches the spread position by pivoting in the first direction, the forwardly-offset center of gravity of the construction machine is moved rearwardly. Consequently, the construction machine can maintain balance, thereby ensuring positional stability. In this case, the piston of the cylinder 231 is elastically deformed, so that the first arm 234 and the second arm 235 are spread.

The third mode indicates a position in which the counterweight 120 has pivoted in the second direction from the second mode. The finally-pivoted position of the counterweight 120 in the third mode is the same as the initially-mounted state of the counterweight 120 in the first mode. Specifically, in the case in which the center of gravity of the construction machine in the second mode is offset rearwardly due to the working environment, when the operator rotates the roller 132 in the second direction by manipulating the controller 140, the gear train 135 connected to the roller 132 rotates, so that the holding link member 134 pivots in the second direction. When the holding link member 134 is separated from the counterweight 120, the piston of the cylinder 231 is moved by elastic restoring force, so that the first arm 234 and the second arm 235 are gradually folded about the connector 233 acting as a hinge shaft. Consequently, the counterweight 120 gradually pivots in the second direction. In this case, the operator may apply additional force to the piston of the cylinder 231 by manipulating the controller 140, thereby helping the counterweight 120 to smoothly pivot.

When the counterweight 120 returns to the initially-mounted position by pivoting in the second direction, the center of gravity of the construction machine that has been offset rearwardly is moved forwardly. Consequently, the construction machine can maintain balance, thereby ensuring positional stability.

The second exemplary embodiment can more firmly support the counterweight 120 and the pivoting of the counterweight 120, since the second pivot control module 230 in the shape of a door closer is provided in place of the wire (131 in FIG. 2) according to the second exemplary embodiment.

The foregoing descriptions of specific exemplary embodiments of the present disclosure have been presented with respect to the drawings and are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed herein, and many modifications and variations are obviously possible for a person having ordinary skill in the art in light of the above teachings.

It is intended therefore that the scope of the present disclosure not be limited to the foregoing embodiments, but be defined by the Claims appended hereto and their equivalents.

100: Construction machine 110: Frame

111: Lower traveling body 112: Upper swing body

120: Counterweight 121: Pin

122: Hook

130: Pivot control module, First pivot control module

131: Wire 132: Winder, Roller

133: Guide 134: Holding link member

135: Gear train 136: First gear

137: Second gear 138: Third gear

140: Controller 10: Working machine

11: Boom 12: Arm

13: Bucket 20: Cab

30: Engine room

230: Second pivot control module

231: Cylinder 232: Holder

233: Connector 234: First arm

235: Second arm

Claims

A construction machine comprising:

a frame, wherein a working device is disposed on a front portion thereof;

a counterweight having a bottom end coupled to a rear portion of the frame using a pin, wherein the counterweight pivots about the pin and is fixed in a position in which pivoting of the counterweight is completed;

a pivot control module connected between the frame and the counterweight to control the counterweight to pivot in a first direction, or a second direction, opposite to the first direction; and

a controller electrically connected to the pivot control module to move a center of gravity of the construction machine by operating the pivot control module.
The construction machine of claim 1, wherein the pivot control module is provided on both sides of the frame in a width direction and on both sides of the counterweight in a width direction, wherein the front portion and the rear portion are categorized based on a direction in which the construction machine travels, and the width direction is perpendicular to the direction in which the construction machine travels.
The construction machine of claim 2, wherein the pivot control module comprises:

a wire connecting the rear portion of the frame and the counterweight;

a winder disposed on the frame and connected to the wire, the winder being rotatable about an axis thereof to wind or unwind the wire to allow the counterweight to pivot; and

a guide disposed on a path along which the wire moves to guide the movement of the wire.
The construction machine of claim 3, wherein the wire holds the counterweight to be fixed in the position in which the pivoting of the counterweight is completed.
The construction machine of claim 4, wherein the counterweight comprises a hook configured to catch one end of the wire.
The construction machine of claim 3, wherein the pivot control module further comprises a holding link member having one and the other longitudinal ends connected to the winder and the counterweight, respectively, wherein the holding link member pivots in response to an operation of the winder to push the counterweight to pivot and, after the counterweight has pivoted in the first direction, prevents the counterweight from pivoting in the second direction.
The construction machine of claim 6, wherein the control module further comprises a gear train connecting the winder and the holding link member such that the holding link member pivots in concert with the operation of the winder.
The construction machine of claim 7, wherein the gear train comprises:

a first gear disposed on a rotary shaft of the winder;

a second gear disposed on a longitudinal end of the holding link member to be rotated by the first gear; and

a third gear disposed between the first gear and the second gear to allow the second gear to rotate in the same direction as the first gear.
A construction machine comprising:

a frame, wherein a working device and a cab are disposed on a front portion thereof and an engine room is disposed on a rear portion thereof;

a counterweight having a bottom end coupled to a rear portion of the frame using a pin, wherein the counterweight pivots about the pin and is fixed in a position in which pivoting of the counterweight is completed;

a first pivot control module connected between the frame and the counterweight to control the counterweight to pivot in a first direction;

a second pivot control module connected between the frame and the counterweight to control the counterweight to pivot in a second direction, opposite to the first direction; and

a controller electrically connected to the pivot control module to move a center of gravity of the construction machine by operating the pivot control module.
The construction machine of claim 9, wherein the first pivot control module is provided on both sides of the frame in a width direction and on both sides of the counterweight in a width direction, and the second pivot control module is provided on both sides of the engine room in a width direction and on both sides of the counterweight in a width direction, wherein the front portion and the rear portion are categorized based on a direction in which the construction machine travels, and the width direction is perpendicular to the direction in which the construction machine travels.
The construction machine of claim 10, wherein the first pivot control module comprises:

a roller disposed on the frame; and

a holding link member having one and the other longitudinal ends connected to the roller and the counterweight, respectively, wherein the holding link member pivots in response to an operation of the roller to push the counterweight to pivot and, after the counterweight has pivoted in the first direction, prevents the counterweight from pivoting in the second direction.
The construction machine of claim 11, wherein the first control module further comprises a gear train connecting the roller and the holding link member such that the holding link member pivots in concert with the operation of the roller.
The construction machine of claim 12, wherein the gear train comprises:

a first gear disposed on a rotary shaft of the roller;

a second gear disposed on a longitudinal end of the holding link member to be rotated by the first gear; and

a third gear disposed between the first gear and the second gear to allow the second gear to rotate in the same direction as the first gear.
The construction machine of claim 9, wherein the second pivot control module comprises:

a cylinder disposed outside of the engine room, containing oil therein, and having a piston elastically disposed therein;

a first arm having one longitudinal end coupled to the cylinder;

a connector connected to the other longitudinal end of the first arm;

a second arm having one longitudinal end hinge-coupled to the connector; and

a holder disposed on the counterweight, the other longitudinal end of the second arm being coupled to the holder.
The construction machine of claim 14, wherein the cylinder is connected to the controller and is operated by the controller.