ATTACHMENT ATTACHMENT/DETACHMENT DEVICE

Abstract

 In an attachment attaching/detaching device 2, a fixed hook 22 that engages a first pin 51 of an attachment 5, and a movable hook 23 that moves toward and away from the fixed hook 22 and engages a second pin 52 of the attachment 5 are provided in an arm connection part 21 to which an arm 12 and a rod or a link 15 are connected. A tilt switch 46 that switches between allowing a flow of current and cutting off a flow of current depending on a tilted posture is mounted to the arm connection part 21 in a state in which the tilt switch 46 is interposed along a shared power supply line 283 to electric driving means for causing the movable hook 23 to advance and retreat. Thus, safety securing means that replaces a locking mechanism is realized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an attachment attaching/detaching device that is interposed between an arm of a construction machine and an attachment.

BACKGROUND

[0002] There is a known attachment attaching/detaching device, which is interposed between an arm of a construction machine and an attachment, in a configuration that includes an arm connection part to which an arm and a rod or a link are connected and which is provided with a fixed hook that engages a first pin of an attachment, and a movable hook that moves toward and away from the fixed hook and engages a second pin of the attachment (JP 2021-161788 A). The attachment attaching/detaching device disclosed in Patent Literature 1 has a key block that can freely advance and retreat along an inner peripheral edge of the fixed hook, and even in a case where the movable hook becomes disengaged from the second pin of the attachment, the first pin of the attachment does not become disengaged from the fixed hook, and thus the safety at the time of detaching an attachment is increased.

SUMMARY

[0003] An advantageous effect produced by a locking mechanism typified by a key block is the safety at the time of detaching an attachment associated with the attachment attaching/detaching device disclosed in JP 2021-161788 A. Many other traditional attachment attaching/detaching devices are also equipped with such kind of locking mechanism. In some cases, however, a locking mechanism may not be employed in a smaller attachment attaching/detaching device in which space for arranging the locking mechanism cannot be secured. In the case of an attachment device that does not have a locking mechanism, if the movable hook becomes disengaged from the second pin, the first pin may also become disengaged from the fixed hook depending on the tilted posture of the attachment (a posture determined by rotation around an arm connecting shaft), and in the worst case there is a risk that the attachment will fall off.

[0004] Currently, it is necessary to rely on visual observation by the operator to check the tilted posture of an attachment, which makes it difficult to ensure a safe tilted posture. Further, in some cases the movable hook is moved unconsciously in an attempt to detach the attachment, without checking the tilted posture of the attachment. Consequently, with respect to an attachment attaching/detaching device that does not have a locking mechanism, the safety at the time of detaching an attachment has not been sufficient. Therefore, with regard to attachment attaching/detaching devices that do not have a locking mechanism, studies have been conducted for realizing safety securing means in place of a locking mechanism so that, even if the movable hook becomes disengaged from the second pin, the attachment can be detached without the first pin becoming disengaged from the fixed hook.

[0005] A device that has been developed as a result of the aforementioned studies is an attachment attaching/detaching device including an arm connection part to which an arm and a rod or a link are connected, the arm connection part provided with a fixed hook that engages a first pin of an attachment, and a movable hook that moves toward and away from the fixed hook and engages a second pin of the attachment, wherein a tilt switch that switches between allowing a flow of current and cutting off a flow of current depending on a tilted posture is mounted to the arm connection part in a state in which the tilt switch is interposed along a power supply line or a signal line to electric driving means for causing the movable hook to advance or retreat.

[0006] In the attachment attaching/detaching device of the present disclosure, a tilt switch that switches between allowing a flow of current and cutting off a flow of current depending on a tilted posture is used so that the movable hook is not allowed to advance or retreat unless the attachment attaching/detaching device assumes a specific turned posture. The tilt switch takes a horizontal state as a reference state, and allows a flow of current when one end (for example, a cable lead-out end) descends relative to the horizontal state, and cuts off the flow of current when the one end rises relative to the horizontal state. The relation between the tilted posture of the tilt switch and allowing the flow of current and cutting off the flow of current may be the reverse of the aforementioned relation. Thus, the tilt switch can be mounted to the arm connection part in such a manner that one end of the tilt switch descends from a horizontal state in accordance with a tilted posture of the attachment attaching/detaching device, at which posture no problem occurs even if the movable hook advances or retreats. In this way, the flow of a current to a power supply line or a signal line of the electric driving means is cut off and the electric driving means is not activated unless the attachment attaching/detaching device assumes a specific tilted posture, and thus the movable hook can be prevented from advancing and retreating.

[0007] The electric driving means may be any driving means with which advancing and retreating of the movable hook is electrically controlled directly or indirectly. The power supply line supplies electric power for driving to the electric driving means. The signal line transmits control signals that activate or stop the electric driving means. The tilt switch is interposed along either one of the power supply line and the communication line so that advancing and retreating of the movable hook can be regulated. Here, in a case where the movable hook is caused to advance and retreat using a hydraulic cylinder, preferably the electric driving means is configured as a hydraulic cylinder to which an electromagnetic valve that switches a connection port when a current flows to the power supply line or the signal line is connected. An operation switch or an operation lever for the power supply line or the signal line is provided at the driver's seat, and the tilt switch is interposed along the power supply line or the signal line inside the attachment attaching/detaching device.

[0008] Preferably, the tilt switch is mounted to the arm connection part in a tilted posture such that the tilt switch allows the flow of current if the center of gravity of the attachment attached to the attachment attaching/detaching device is located on a side which is further away from the movable hook than a position directly below the center of the fixed hook. By this means, in a state in which the tilt switch allows the flow of current, which is equal to a state in which the movable hook can advance and retreat, a state can be entered in which a rotational force in a direction that brings the second pin closer to the movable hook that is centered on the first pin which is engaged with the fixed hook is imparted to the attachment, and the risk of the first pin disengaging from the fixed hook is approximately eliminated.

[0009] In the attachment attaching/detaching device of the present disclosure, a tilted posture of the tilt switch that is required when mounting the tilt switch to the arm connection part differs slightly depending on the type of attachment to be connected to the attachment attaching/detaching device. From this point on, preferably the tilted posture at which the tilt switch is mounted to the arm connection part is freely adjustable. Because the tilted posture of the tilt switch is freely adjustable, the tilted posture can be adjusted each time an attachment connected to the attachment attaching/detaching device changes, and a tilted posture that allows the movable hook to advance and retreat can be specified for each attachment. Examples of adjustment means for adjusting the tilted posture that may be mentioned include a configuration in which the tilt switch is mounted on a rotatable base provided on the connecting arm part, and a configuration in which a bolt that fixes the tilt switch to the connecting arm part is passed through a long hole.

[0010] The attachment attaching/detaching device of the present disclosure can prevent the movable hook from advancing and retreating unless the attachment attaching/detaching device assumes a specific tilted posture. This is an advantageous effect achieved by the tilt switch mounted to the arm connection part. By this means, the risk that, when the movable hook is detached from the second pin of the attachment, the attachment will rotate around the first pin and will fall off from the attachment attaching/detaching device can be reduced or eliminated. In this way, the safety is ensured when detaching an attachment in an attachment attaching/detaching device that does not have a locking mechanism.

[0011] In the attachment attaching/detaching device of the present disclosure, the tilt switch that switches between allowing the flow of current and cutting off the flow of current depending on a tilted posture is used so that the movable hook is not allowed to advance or retreat unless the attachment attaching/detaching device assumes a specific tilted posture. The tilt switch takes the horizontal state as a reference state, and allows (or cuts off) a flow of current when one end (for example, a cable lead-out end) thereof descends relative to the horizontal state, and cuts off (or allows) the flow of current when the one end rises relative to the horizontal state. Thus, the tilt switch can be mounted to the arm connection part in such a manner that one end of the tilt switch descends from a horizontal state in accordance with a tilted posture of the attachment attaching/detaching device, at which posture no problem occurs even if the movable hook advances or retreats. In this way, the movable hook can be prevented from advancing and retreating unless the attachment attaching/detaching device assumes a specific tilted posture.

[0012] If the electric driving means is configured as a hydraulic cylinder connected to an electromagnetic valve that switches a connection port when a current flows to the power supply line or the signal line, the present disclosure can be applied to a hydraulic system used in a construction machine as is by merely interposing the tilt switch along a power supply line or a signal line of the electromagnetic valve. This means that the present disclosure can be constructed without requiring a major modification to an existing attachment attaching/detaching device as long as there is sufficient installation space for mounting the tilt switch in an arm connection part. Hence, the present disclosure can be easily used in a small-sized attachment attaching/detaching device that does not have a locking mechanism.

[0013] When the tilt switch is mounted to the arm connection part in a tilted posture such that the tilt switch allows the flow of current if the center of gravity of the attachment attached to the attachment attaching/detaching device is located on a side which is further away from the movable hook than a position directly below the center of the fixed hook, in a state in which the tilt switch allows the flow of current, for example, a state can be entered in which the second pin is pressed against the pin receiver of the arm connection part that faces the movable hook and the first pin does not disengage from the fixed hook, and therefore the attachment can be prevented from falling out due to inadvertent rotation of the attachment. Such a tilted posture of the tilt switch differs for each attachment to be attached to the attachment attaching/detaching device, and is determined individually.

[0014] Further, when the tilted posture at which the tilt switch is mounted to the arm connection part is freely adjustable, the tilted posture of the attachment attaching/detaching device at which the tilt switch allows the flow of current can be freely determined. The tilt switch whose tilted posture is freely adjustable is suitable for a case where the tilted posture of the tilt switch that can prevent an attachment from falling out due to inadvertent rotation of the attachment is adjusted according to the combination of the attachment attaching/detaching device and the attachment. By this means, even if the attachment attached to the attachment attaching/detaching device is changed, the present disclosure can be utilized by merely adjusting the tilted posture of the tilt switch.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 

Fig. 1 is a side view illustrating one example of a construction machine that uses the attachment attaching/detaching device of the present disclosure;

Fig. 2 is a block diagram for describing the configuration of main parts in the attachment attaching/detaching device of the present example;

Fig. 3 is a partially enlarged side view illustrating procedure 1 for detaching an attachment from the attachment attaching/detaching device of the present example;

Fig. 4 is a partially enlarged side view illustrating procedure 2 for detaching an attachment from the attachment attaching/detaching device of the present example;

Fig. 5 is a partially enlarged side view illustrating procedure 3 for detaching an attachment from the attachment attaching/detaching device of the present example; and

Fig. 6 is a partially enlarged side view illustrating procedure 4 for detaching an attachment from the attachment attaching/detaching device of the present example.

DETAILED DESCRIPTION OF THE EMBODIMENT

[0016] Hereunder, one form for carrying out the present disclosure is described while referring to the accompanying drawings. An attachment attaching/detaching device 2 of the present disclosure that does not have a locking mechanism is suitably used in a small-sized construction machine 1, as illustrated in Fig. 1. The attachment attaching/detaching device 2 of the present example connects an arm 12 of the construction machine 1 and a link 15 extending from a swing lever 14 to which a rod for an attachment 131 of a hydraulic cylinder for an attachment 13 is connected, to an arm connection part 21, and causes a first pin 51 to engage with a fixed hook 22 and causes a second pin 52 to engage with a movable hook 23 to thereby attach an attachment (in the present example, a bucket) 5 to the arm connection part 21. An operation switch 45 (see Fig. 2) for performing operations to advance and retract the movable hook 23 is provided in a driver's seat 11.

[0017] As illustrated in Fig. 2, the attachment attaching/detaching device 2 of the present example is constituted by a hydraulic system 3 (indicated by a thick line) that causes the movable hook 23 to advance and retreat and an electrical system 4 (indicated by a thin line) which are the same as the traditional hydraulic system and electrical system, and a tilt switch 46 that is additionally provided in the electrical system 4. The tilt switch 46 does not require any external operating means, and only needs to be interposed along a power supply line or a signal line of the electrical system 4. Furthermore, the tilt switch 46 is small and does not require a large installation space. Thus, the present disclosure can be utilized by adding the tilt switch 46 to an attachment attaching/detaching device 2 which is already manufactured, and provides the advantage that safety at the time of detaching the attachment 5 can be added to an attachment attaching/detaching device 2 which is already manufactured that does not have a locking mechanism.

[0018] The arm connection part 21 has a structure in which two side plates 211 made of metal which are each substantially a parallelogram in side view are held parallel to each other, and all or one part of the hydraulic system 3 and the electrical system 4 is arranged between the side plates 211. The tilt switch 46 of the present example has a cylindrical shape extending from one end to which a shared power supply line 41 is connected, and is fixed to the inner side of one of the side plates 211 by a first fixing bolt 461 which is closer to one end side, and a second fixing bolt 462 which is closer to the other end side. The second fixing bolt 462 fixes the tilt switch 46 by passing through an arcuate long hole 215 provided in the side plate 211. The arcuate long hole 215 is a curved long hole which is centered on the first fixing bolt 31. Thus, the tilted posture of the tilt switch 3 can be adjusted by changing the fixing position of the second fixing bolt 462 with respect to the arcuate long hole 215.

[0019] In the arm connection part 21, an arm connection shaft 212 on one end side (right side in Fig. 2) of a concave upper edge of the side plate 211 and a link connection shaft 213 on the other end side (left side in Fig. 2) are provided spanning between the left and right side plates 211, with the arm 12 being rotatably connected to the arm connection shaft 212, and the link 15 being rotatably connected to the link connection shaft 213. Further, in the arm connection part 21, a hook-shaped fixed hook 22 that opens outward is provided on one end side of a linear lower edge of each side plate 211. Since the fixed hook 22 is provided in each of the side plates 211, there is a pair of left and right fixed hooks 22, and each of the fixed hooks 22 is engaged with the first pin 51 of the attachment 5.

[0020] In the arm connection part 21, a pin receiver 214 having the shape of a substantially 1/4 arc that opens downward is formed on the other end side of the linear lower edge of each side plate 211. The movable hook 23 is a hook-shaped portion in side view that is in internal contact with the side plates 211 and protrudes in the forward direction (the left direction in Fig. 2) from a metal block 23 that moves forward and backward. The pin receiver 214 and the movable hook 23 that has advanced to a position directly below the pin receiver 214 are in a positional relationship in which they face each other in the vertical direction, and in a state in which the pin receiver 213 restrains the left and right sides of the second pin 52 of the attachment 5 from above, the movable hook 23 supports the middle part between the left and right sides of the second pin 52 from below to thereby sandwich the second pin 52. When the movable hook 23 retreats, the second pin 52 is released at the lower part of the pin receiver 214, and the second pin 52 separates from the pin receiver 214.

[0021] The metal block 231 incorporates therein a tube of a hydraulic cylinder for a hook 232, and connects a rod for a hook 233 to a position fixing block 234 that is fixed to the side plate 211. By this means, when the rod for a hook 233 is expanded or contracted, the metal block 231 approaches or moves away from the position fixing block 233, and thus the movable hook 23 can advance and retreat. The hydraulic cylinder for a hook 232 may connect the tube to the position fixing block 234, and connect the rod for a hook 233 that expands and contracts to the metal block 231.

[0022] The hydraulic system 3 of the present example has a configuration in which a tank-side first hydraulic line 32 and a tank-side second hydraulic line 33 that are connected to an oil tank 31, and a cylinder-side first hydraulic line 35 and a cylinder-side second hydraulic line 36 that are connected to the hydraulic cylinder for a hook 232 are connected through an electromagnetic valve 34 that is a threeposition switching valve. The tank-side first hydraulic line 31 is provided with a hydraulic pump 321. In the present example, electric driving means for the movable hook 23 is constituted by the electromagnetic valve 34 and the hydraulic cylinder for a hook 232.

[0023] The cylinder-side first hydraulic line 35 is provided with a first check valve 351 that is connected to a base end side (left side in Fig. 2) of the tube of the hydraulic cylinder for a hook 231, and at which a first pilot line 352 is connected to the cylinder-side second hydraulic line 36. The cylinder-side second hydraulic line 36 is provided with a second check valve 361 that is connected to a rod side (right side in Fig. 2) of the tube of the hydraulic cylinder for a hook 231, and at which a second pilot line 362 is connected to the cylinder-side first hydraulic line 35.

[0024] As long as oil does not flow into either of the cylinder-side first hydraulic line 35 and the cylinder-side second hydraulic line 36, the first check valve 351 and the second check valve 361 prevent the movement of oil that remains in the tube of the hydraulic cylinder for a hook 231, and thereby ensure that the movable hook 23 does not move inadvertently. In the attachment attaching/detaching device 2 of the present example, unless the tilt switch 46 has assumed a specific tilted posture, the supply of electric power to the tilt switch 46 is cut off and the electromagnetic valve 34 is not actuated. This creates a state in which oil does not flow to either of the cylinder-side first hydraulic line 35 and the cylinder-side second hydraulic line 36 when the attachment attaching/detaching device 2 has assumed a posture other than a specific tilted posture, and thus safety such that the movable hook 23 cannot be moved is achieved by utilizing the action of the first check valve 351 and the second check valve 361.

[0025] In the electromagnetic valve 34, when electric power is supplied from a first power supply line 42 to a solenoid for a first section 342 by operation of the operation switch 45, the electromagnetic valve 34 is pushed by the solenoid for a first section 342 and switches a connection relationship between the hydraulic lines from a central section 343 to a first section 341. Further, when the operation switch 45 is switched to a neutral state from the power supply state and the power supply from the first power supply line 42 is stopped, the electromagnetic valve 34 is pulled back by the action of urging means (for example, a coil spring), and the connection relationship between the hydraulic lines returns to the central section 343 from the first section 341.

[0026] In the electromagnetic valve 34, when electric power is supplied from a second power supply line 43 to a second section solenoid 345 by operation of the operation switch 45, the electromagnetic valve 34 is pushed by the second section solenoid 345 and switches the connection relationship between the hydraulic lines from the central section 343 to a second section 344. Further, when the operation switch 45 is switched to a neutral state from the power supply state and the power supply from the second power supply line 43 is stopped, the electromagnetic valve 34 is pulled back by the action of urging means (for example, a coil spring), and the connection relationship between the hydraulic lines returns to the central section 343 from the second section 344. The central section 343 cuts off the connection between the tank-side first hydraulic line 32 and the cylinder-side first hydraulic line 35, and connects the cylinder-side first hydraulic line 35 and the cylinder-side second hydraulic line 36.

[0027] The first section 341 connects the tank-side first hydraulic line 32 and the cylinder-side first hydraulic line 35 and connects the tank-side second hydraulic line 33 and the cylinder-side second hydraulic line 36, to thereby send oil from the tank-side first hydraulic line 32 to the base end side of the tube of the hydraulic cylinder for a hook 231 via the cylinder-side first hydraulic line 35, and return oil from the rod side of the tube to the oil tank 31 via the cylinder-side second hydraulic line 37 and the tank-side second hydraulic line 33. Thus, when the operation switch 45 is switched from the central section 343 to the first section 341, the metal block 231 moves forward (moves to the left in Fig. 2), which causes the movable hook 23 to protrude below the pin receiver 214.

[0028] The second section 344 connects the tank-side first hydraulic line 32 and the cylinder-side second hydraulic line 36 and connects the tank-side second hydraulic line 33 and the cylinder-side first hydraulic line 35, to thereby send oil from the tank-side first hydraulic line 32 to the rod side of the tube of the hydraulic cylinder for a hook 231 via the cylinder-side second hydraulic line 36, and return oil from the base end side of the tube to the oil tank 31 via the cylinder-side first hydraulic line 35 and the tank-side second hydraulic line 33. Thus, when the operation switch 45 is switched from the central section 343 to the second section 344, the metal block 231 moves backward (moves to the right in Fig. 2), which causes the movable hook 23 to retreat from below the pin receiver 214.

[0029] The electrical system 4 of the present example is constituted by connecting the high voltage side of the first power supply line 42 that extends from the operation switch 45 to the solenoid for a first section 342 of the electromagnetic valve 34, and similarly connecting the high voltage side of the second power supply line 43 that extends from the operation switch 45 to the second section solenoid 345 of the electromagnetic valve 34, connecting the high voltage side of the shared power supply line 41 that bundles together the low voltage sides of the first power supply line 42 and the second power supply line 43 that extend from the solenoid for a first section 342 and the second section solenoid 345 to the tilt switch 46, and returning the low voltage side of the shared power supply line 41 that extends from the tilt switch 46 to the operation switch 45. A power supply 44 is provided on the shared power supply line 41.

[0030] If the operation switch 45 is operated when the tilt switch 46 is in a state allowing the flow of current and a current is passed through the first power supply line 42, the solenoid for a first section 342 is activated and the electromagnetic valve 34 is switched from the central section 343 to the first section 341, and the movable hook 23 is caused to move forward. Further, if the operation switch 45 is operated when the tilt switch 46 is in a state allowing the flow of current and a current is passed through the second power supply line 42, the second section solenoid 345 is activated and the electromagnetic valve 34 is switched from the central section 343 to the second section 344, and the movable hook 23 is caused to retreat. With respect to all of the operations of the operation switch 45, if the tilt switch 46 is not in a state allowing the flow of current, the electromagnetic valve 34 cannot be switched, and the movable hook 23 cannot be caused to move forward or to retreat.

[0031] Procedures for detaching the attachment 5 in the attachment attaching/detaching device 2 of the present example will now be described. The tilt switch 46 of the present example is designed so as to enter a state that cuts off the flow of current when the tilt switch 46 is in a tilted posture in which one end that is connected to the shared power supply line 41 is at an angle of elevation (upward tilt angle) that is equal to or greater than the horizontal, and to enter a state that allows a flow of current when the tilt switch 46 is in a tilted posture in which the one end is at an angle of depression (downward tilt angle) that is less than the horizontal. Further, when the center of gravity G of the attachment 5 attached to the attachment attaching/detaching device 2 is on a side further away from the movable hook 23 than a position directly below the fixed hook 22, the tilt switch 46 is attached to the side plate 211 of the arm connection part 21 in a tilted posture in which the one end is at an angle of depression (see Fig. 3).

[0032] In a state of procedure 1 when starting the operation to detach the attachment 5, as illustrated in Fig. 3, the first pin 51 of the attachment 5 is engaged with the fixed hook 22, and the second pin 52 of the attachment 5 is engaged with the movable hook 23 from below and sandwiched between the movable hook 23 and the pin receiver 214, and there is no risk of the attachment 5 falling off unless, for example, the hydraulic cylinder for a hook 232 inadvertently causes the rod for a hook 233 to retract. However, since the tilt switch 46 is in a tilted posture with one end at an angle of depression (see the thin solid arrow in Fig. 3), in the state of procedure 1, it is possible to supply electric power to the electromagnetic valve 34 through the electrical system 4.

[0033] From the state of procedure 1 in which it is possible to supply electric power to the electromagnetic valve 34 through the electrical system 4 (see Fig. 3), when the operation switch 45 is operated to supply electric power from the second power supply line 43 to activate the second section solenoid 345, the electromagnetic valve 34 switches the connection relationship from the central section 343 to the second section 344 to thereby send oil to the rod side of the tube of the hydraulic cylinder for a hook 232 through the second hydraulic line for cylinder 36, and as illustrated in Fig. 4, the state of procedure 2 in which the movable hook 23 has been retracted can be achieved (the movable hook 23 is hidden by the side plate 211 and is not shown).

[0034] In the state of procedure 2 (see Fig. 4), the attachment 5 is a state in which the first pin 51 is simply engaged with the fixed hook 22. However, because the center of gravity G of the attachment 5 is on a side that is farther from the movable hook 23 than a position directly below the center of the fixed hook 22, a rotational force (see the dashed outline arrow in Fig. 4) in a direction approaching the movable hook 23 that is centered on the first pin 51 which is engaged with the fixed hook 22 is imparted to the attachment 5, the second pin 52 is pushed against the pin receiver 214, and the first pin 51 does not deviate in a direction away from the fixed hook 22, and thus there is no risk of the attachment 5 falling off.

[0035] Here, when the hydraulic cylinder for an attachment 13 is actuated from the state of procedure 2 (see Fig. 4) to cause the rod for an attachment 131 to retract, as illustrated in Fig. 5, the attachment attaching/detaching device 2 is rotated so as to be raised upward (right rotation in Fig. 5; see the white outlined arrow), and the tilt switch 46 enters the state of procedure 3 in which one end is at an angle of elevation (see the thin dashed-line arrow in Fig. 5). The attachment 5 is rotated around the first pin 51 engaged with the fixed hook 22 in a direction that brings the center of gravity G closer to movable hook 23 (right rotation in Fig. 5), and rotation of the attachment 5 is stopped at a stage when the center of gravity G is located directly below the center of the fixed hook 22, and thereafter only rotation of the attachment attaching/detaching device 2 with respect to the attachment 5 which is fixed in position is continued.

[0036] In the state of procedure 3, because one end of the tilt switch 46 is at an angle of elevation, it is not possible for the electrical system 4 to supply power, and an operation to move the movable hook 23 forward or backward by operating the operation switch 45 is restricted. This is to ensure that the movable hook 23 does not inadvertently advance or retreat when subsequently detaching the attachment 5 completely from the attachment attaching/detaching device 2, and also to ensure that when attaching the attachment 5 to the attachment attaching/detaching device 2 once again, the movable hook 23 cannot move forward unless the attachment attaching/detaching device 2 is in a tilted posture in which the first pin 51 cannot come out from the fixed hook 22. Thus, work for attaching and detaching the attachment 5 is carried out in a safe state that prevents the attachment 5 from falling off.

[0037] From the state of procedure 3 (see Fig. 5), when raising of the attachment attaching/detaching device 2 is continued to place the attachment attaching/detaching device 2 in a tilted posture in which the fixed hook 22 opens in the downward direction, as illustrated in Fig. 6, the first pin 51 of the attachment 5 is released from the fixed hook 22, and the state of procedure 4 is entered in which the attachment 5 is completely separated from the attachment attaching/detaching device 2. In this case, by placing the attachment 5 on the ground and then lifting the attachment attaching/detaching device 2 upward, the risk of dropping the attachment 5 can be eliminated. As described above, although the attachment attaching/detaching device 2 of the present disclosure does not have a locking mechanism, the attachment 5 can be safely detached simply by operating the operation switch 45 of the electrical system 4 and changing the tilted posture of the attachment attaching/detaching device 2.

REFERENCE SIGNS LIST

[0038] 

1

Construction Machine

11

Driver's Seat

12

Arm

13

Hydraulic Cylinder for an Attachment

131

Rod for an Attachment

14

Swing lever

15

Link

2

Attachment Attaching/Detaching Device

21

Arm Connection Part

211

Side Plate

212

Arm Connection Shaft

213

Link Connection Shaft

214

Pin Receiver

215

Arcuate Long Hole

22

Fixed Hook

23

Movable Hook

231

Metal Block

232

Hydraulic Cylinder for a Hook

233

Rod for a Hook

234

Position Fixing Block

3

Hydraulic System

32

Tank-side First Hydraulic Line

33

Tank-side Second Hydraulic Line

34

Electromagnetic Valve

35

Cylinder-side First Hydraulic Line

36

Cylinder-side Second Hydraulic Line

4

Electrical System

41

Shared Power Supply Line

42

First Power Supply Line

43

Second Power Supply Line

44

Power Supply

45

Operation Switch

46

Tilt Switch

461

First Fixing Bolt

462

Second Fixing Bolt

5

Attachment

51

First Pin

52

Second Pin

G

Center of Gravity

Claims

1. An attachment attaching/detaching device comprising
an arm connection part to which an arm and a rod or a link are connected, the arm connection part provided with:

a fixed hook that engages a first pin of an attachment; and

a movable hook that moves toward and away from the fixed hook and engages a second pin of the attachment,

wherein

a tilt switch that switches between allowing a flow of current and cutting off a flow of current depending on a posture is mounted to the arm connection part in a state in which the tilt switch is interposed along a power supply line or a signal line to electric driving means for causing the movable hook to advance or retreat.

2. The attachment attaching/detaching device according to claim 1, wherein:
the electric driving means is a hydraulic cylinder to which an electromagnetic valve that switches a connection port when a current flows to the power supply line or the signal line is connected.

3. The attachment attaching/detaching device according to claim 1, wherein:
the tilt switch is mounted to the arm connection part in a tilted posture such that the tilt switch allows the flow of current if the center of gravity of the attachment attached to the attachment attaching/detaching device is located on a side which is further away from the movable hook than a position directly below the center of the fixed hook.

4. The attachment attaching/detaching device according to claim 1, wherein:
the tilted posture at which the tilt switch is mounted to the arm connection part is freely adjustable.

Drawing