JP7213606B1 - Attachment removal device - Google Patents

Abstract

A fixed hook 22 for engaging the first pin 51 of the attachment 5 with the arm connection portion 21 to which the arm 12, rod or link 15 is connected, and the second pin 52 of the attachment 5 is engaged with the fixed hook 22 by approaching and separating from the fixed hook 22. In the attachment attaching/detaching device 2 provided with the movable hook 23 to be engaged, the tilt switch 3 that switches between energization and cut-off depending on the tilted posture is interposed in the shared power supply line 283 to the electric drive means that moves the movable hook 23 forward and backward. It is characterized by being attached to the connecting part 21 and realizes a safety ensuring means in place of the locking mechanism. [Selection drawing] Fig. 3

Description

The present invention relates to an attachment attaching/detaching device interposed between an arm and an attachment of a construction machine.

An attachment attaching/detaching device intervening between an arm and an attachment of a construction machine consists of a fixed hook that engages the first pin of the attachment with the arm connecting part to which the arm, rod or link is connected, and the fixed hook that moves toward and away from the fixed hook. A configuration is known in which a movable hook for engaging the second pin of the attachment is provided (Patent Document 1). The attachment attaching/detaching device disclosed in Patent Document 1 has a key block that can move back and forth on the inner peripheral edge of the fixed hook. It is designed to prevent the attachment from slipping, and the safety is enhanced when the attachment is removed.

Japanese Patent Application Laid-Open No. 2021-161788

The safety of the attachment attaching/detaching device disclosed in Patent Document 1 at the time of attachment removal is an effect obtained by a lock mechanism represented by a key block. Many conventional attachment attaching/detaching devices also have such a locking mechanism. However, if the attachment attaching/detaching device is small, the lock mechanism may not be used because it is difficult to secure a place for installation. In an attachment device that does not have a locking mechanism, when the movable hook is removed from the second pin, the first pin is also removed from the fixed hook due to the inclined posture of the attachment (posture determined by rotation about the arm connecting shaft). In the worst case, there is a danger that the attachment will fall.

At present, it is difficult to secure a safe tilted posture of the attachment because it depends on the operator's visual inspection. In addition, the movable hook may be unintentionally moved to remove the attachment without checking the tilted posture of the attachment. rice field. Therefore, in an attachment attaching/detaching device without a lock mechanism, there is provided a safety assurance means that replaces the lock mechanism so that the attachment can be removed without removing the first pin from the fixed hook even if the movable hook is disengaged from the second pin. In order to realize

What was developed as a result of examination is a fixed hook that engages the 1st pin of the attachment to the arm connection part where the arm, rod or link is connected, and the 2nd pin of the attachment that approaches and separates from the fixed hook. In the attachment attaching/detaching device provided with a movable hook that allows the movable hook to move forward and backward, the tilt switch that switches between energization and cutoff according to the tilted posture is interposed in the power supply line or the signal line to the electric drive means that advances and retreats the movable hook. It is an attachment attaching/detaching device characterized by being attached to.

The attachment attaching/detaching device of the present invention does not advance or retract the movable hook unless the attachment attaching/detaching device assumes a specific rotational posture by means of the tilt switch that switches between energization and cut-off according to the tilted posture. The tilt switch energizes when one end (for example, cable lead-out end) is lowered with respect to the horizontal, and cuts off when one end is raised. The relationship between the tilt position of the tilt switch and the energization and cutoff may be reversed. As a result, if the tilt switch is attached to the arm connection part so that one end of the tilt switch is lowered from the horizontal position in accordance with the tilted posture of the attachment detachment device, which does not cause any problem even if the movable hook advances or retreats, the attachment detachment device can be mounted. is not in a specific tilted posture, the power supply line or signal line of the electric drive means is cut off, and the movable hook is prevented from advancing or retreating.

The electric driving means may be any driving means in which forward and backward movement of the movable hook is electrically controlled directly or indirectly. The power supply line supplies driving power to the electric driving means. The signal line transmits control signals for activating or deactivating the electric drive means. The tilt switch is interposed in either the power supply line or the communication line so as to regulate the movement of the movable hook. Here, when the movable hook is advanced and retracted by a hydraulic cylinder, the electric driving means may be configured as a hydraulic cylinder to which an electromagnetic valve that switches the connection port when the power supply line or the signal line is energized is connected. An operation switch or an operation lever for the power supply line or signal line is provided in the driver's seat, and the tilt switch is interposed in the power supply line or signal line in the attachment attaching/detaching device.

The tilt switch is preferably attached to the arm connecting portion in a tilted posture such that the switch is energized when the center of gravity of the attachment attached to the attachment attaching/detaching device is positioned away from the movable hook from directly below the center of the fixed hook. As a result, when the tilt switch is energized and the movable hook can move forward and backward, a rotational force is applied to the attachment in a direction to bring the second pin closer to the movable hook, centering on the first pin engaged with the fixed hook. A state can be achieved in which there is no possibility that the first pin will come off the fixing hook.

In the attachment attaching/detaching device of the present invention, the tilting posture of the tilt switch required when attaching to the arm connecting portion slightly differs depending on the type of attachment to be connected to the attachment attaching/detaching device. Therefore, it is preferable that the tilt switch has an adjustable tilt position attached to the arm connecting portion. Since the tilt switch is adjustable in tilting posture, the tilting posture can be adjusted each time the attachment connected to the attachment attaching/detaching device is changed, and the tilting posture for advancing and retracting the movable hook can be specified for each attachment. Examples of the tilt posture adjusting means include a structure in which the tilt switch is attached to a rotatable base provided in the connection arm portion, and a structure in which a bolt for fixing the tilt switch to the connection arm portion is passed through a long hole.

The attachment attaching/detaching device of the present invention can prevent the movable hook from advancing or retreating unless the attachment attaching/detaching device assumes a specific inclined posture. This is the effect of the tilt switch attached to the arm connection. Thereby, when the movable hook separates from the second pin of the attachment, the attachment rotates around the first pin, and the possibility of falling off from the attachment attaching/detaching device can be reduced or eliminated. In this way, safety is ensured when the attachment is removed in the attachment attaching/detaching device that does not have a lock mechanism.

The attachment attaching/detaching device of the present invention has a tilt switch that switches between energization and cut-off depending on the tilted posture, so that the movable hook does not advance or retreat until the attachment detaching device is in a specific tilted posture. The tilt switch energizes (or cuts off) when one end (for example, cable lead-out end) is lowered with reference to the horizontal, and cuts off (or energizes) when one end is raised. As a result, if the tilt switch is attached to the arm connection part so that one end of the tilt switch is lowered from the horizontal position in accordance with the tilted posture of the attachment detachment device, which does not cause any problem even if the movable hook advances or retreats, the attachment detachment device can be mounted. It is possible to prevent the movable hook from advancing and retreating unless the is in a specific inclined posture.

If the electric drive means is configured as a hydraulic cylinder to which an electromagnetic valve that switches the connection port when the power supply line or signal line is energized is connected, the hydraulic system used in the construction machine can be tilted to the power supply line or signal line of the electromagnetic valve as it is. The present invention can be applied only by interposing a switch. This means that the present invention can be constructed as long as there is an installation space for mounting the tilt switch in the arm connecting portion without requiring a large modification to the existing attachment attaching/detaching device. As a result, the present invention can be easily applied to a small attachment attaching/detaching device that does not have a lock mechanism.

When the tilt switch is attached to the arm connecting portion in a tilted position in which the current is energized when the center of gravity of the attachment attached to the attachment attaching/detaching device is located on the side away from the movable hook from directly below the center of the fixed hook, the current is energized in the tilt switch. For example, the second pin is pressed against the pin receiver of the arm connecting portion facing the movable hook, thereby preventing the first pin from coming off the fixed hook and preventing the attachment from falling due to accidental rotation. Such a tilting posture of the tilt switch differs for each attachment to be attached to the attachment attaching/detaching device, and is determined individually.

Further, if the tilt switch is attached to the arm connecting portion and the tilt position is adjustable, the tilt position of the attachment attaching/detaching device to which the tilt switch is energized can be freely determined. A tilt switch whose tilt position is adjustable is suitable for adjusting the tilt switch's tilt position, which can prevent the attachment from falling due to careless rotation of the attachment, according to the combination of the attachment attaching/detaching device and the attachment. Thus, even if the attachment to be attached to the attachment attaching/detaching device is changed, the present invention can be used only by adjusting the tilting posture of the tilt switch.

1 is a side view showing an example of a construction machine using the attachment attaching/detaching device of the present invention; FIG. FIG. 3 is a block diagram illustrating the configuration of main parts in the attachment attaching/detaching device of the present example; It is a partial enlarged side view showing the procedure 1 which removes an attachment from the attachment attaching/detaching apparatus of this example. It is a partially enlarged side view showing procedure 2 of removing an attachment from the attachment attaching/detaching device of this example. It is a partial enlarged side view showing procedure 3 which removes an attachment from the attachment attaching/detaching device of this example. It is a partial enlarged side view showing procedure 4 which removes an attachment from the attachment attaching/detaching device of this example.

EMBODIMENT OF THE INVENTION Hereafter, it demonstrates, referring a figure for the form for implementing this invention. The attachment attaching/detaching device 2 of the present invention, which does not have a locking mechanism, is preferably used for a small construction machine 1, as shown in FIG. The attachment attaching/detaching device 2 of this example connects an arm 12 of the construction machine 1 and a link 15 extending from a swing lever 14 to which an attachment rod 131 of an attachment hydraulic cylinder 13 is connected to an arm connection portion 21, and a fixed hook. The attachment (a bucket in this example) 5 is attached to the arm connection portion 21 by engaging the first pin 51 with the movable hook 23 and the second pin 52 with the movable hook 23 . An operation switch 45 (see FIG. 2) for advancing and retreating the movable hook 23 is provided on the driver's seat 11 .

As shown in FIG. 2, the attachment attaching/detaching device 2 of this example has the same hydraulic system 3 (shown by thick lines) and electrical system 4 (shown by thin lines) for advancing and retracting the movable hook 23 as before, and the tilt switch 46 is included. It is configured in addition to the electrical system 4 . The tilt switch 46 does not require any external operating means, and only needs to be interposed in the power supply line or signal line of the electrical system 4 . Moreover, the tilt switch 46 is small and does not require a large installation space. As a result, the present invention can be used by adding the tilt switch 46 to the ready-made attachment attaching/detaching device 2, and has the advantage of being able to add safety when removing the attachment 5 to the ready-made attachment attaching/detaching device 2 that does not have a lock mechanism. can get.

The arm connecting portion 21 has a structure in which two metal side plates 211, which are substantially parallelograms when viewed from the side, are held in parallel. . The tilt switch 46 of this example has a columnar shape extending from one end connecting the common feeder line 41, and is held by the side plate 211 with a first fixing bolt 461 brought to one end and a second fixing bolt 462 brought to the other end. inside one of the The second fixing bolt 462 is passed through an arc-shaped elongated hole 215 provided in the side plate 211 and fixed. The arc-shaped elongated hole 215 is a curved elongated hole centered on the first fixing bolt 31 . Thereby, the tilt switch 3 can change the fixing position of the second fixing bolt 462 with respect to the circular long hole 215 to adjust the tilt posture.

The arm connection part 21 has an arm connection shaft 212 on one end side (right side in FIG. 2) of the recessed upper edge of the side plate 211, and a link connection shaft 213 on the other end side (left side in FIG. 2) on the left and right side plates 211. Then, the arm 12 is rotatably connected to the arm connection shaft 212 , and the link 15 is rotatably connected to the link connection shaft 213 . Further, the arm connecting portion 21 is provided with a hook-shaped fixed hook 22 that opens outward on one end side of the linear lower edge of the side plate 211 . Since the fixed hooks 22 are provided on each of the side plates 211 , a pair of right and left fixed hooks 22 are provided, and each hook is engaged with the first pin 51 of the attachment 5 .

The arm connecting portion 21 forms a substantially quarter-arc-shaped pin receiver 214 that opens downward at the other end of the linear lower edge of the side plate 211 . The movable hook 23 is a hook-shaped portion that is inscribed in the side plate 211 and protrudes in the advancing direction (leftward in FIG. 2) from the metal block 23 that advances and retreats. The pin receiver 214 and the movable hook 23 advanced directly below the pin receiver 214 are positioned to face each other in the vertical direction. The second pin 52 is sandwiched by supporting the right and left intermediate portions of the second pin 52 from below. When the movable hook 23 retreats, the lower portion of the pin receiver 214 is released, and the second pin 52 is separated from the pin receiver 214. - 特許庁

The metal block 231 incorporates the tube of the hook hydraulic cylinder 232 and connects the hook rod 233 to the position fixing block 234 fixed to the side plate 211 . As a result, when the hook rod 233 is extended and contracted, the metal block 231 approaches or separates from the position fixing block 233, so that the movable hook 23 can advance and retreat. A hooking hydraulic cylinder 232 may connect a tube to a positioning block 234 and a telescoping hooking rod 233 to a metal block 231 .

The hydraulic system 3 of this example includes a tank-side first hydraulic line 32 and a tank-side second hydraulic line 33 connected to the oil tank 31, and a cylinder-side first hydraulic line 35 and a cylinder-side second hydraulic line connected to the hook hydraulic cylinder 232. line 36 is connected via an electromagnetic valve 34, which is a three-position switching valve. A hydraulic pump 321 is provided in the tank-side first hydraulic line 31 . In this example, the electromagnetic valve 34 and the hook hydraulic cylinder 232 constitute an electric drive means for the movable hook 23 .

The cylinder-side first hydraulic line 35 is connected to the base end side (left side in FIG. 2) of the tube of the hook hydraulic cylinder 231, and the first check valve 351 is connected to the cylinder-side second hydraulic line 36 through the first pilot line 352. is provided. The cylinder-side second hydraulic line 36 is connected to the rod side (right side in FIG. 2) of the tube of the hook hydraulic cylinder 231, and the second check valve 361 connecting the second pilot line 362 to the cylinder-side first hydraulic line 35 is connected. are provided.

The first check valve 351 and the second check valve 361 are designed to prevent the movement of oil remaining in the tube of the hook hydraulic cylinder 231 unless oil flows through either the first hydraulic line 35 on the cylinder side or the second hydraulic line 36 on the cylinder side. to prevent the movable hook 23 from moving carelessly. The attachment attaching/detaching device 2 of this example shuts off the tilt switch 46 and does not operate the electromagnetic valve 34 unless it is in a specific tilted posture. This creates a state in which oil does not flow through either the first cylinder-side hydraulic line 35 or the second cylinder-side hydraulic line 36 unless the attachment attaching/detaching device 2 is in a specific tilted posture, and the first check valve 351 and the second check valve 351 do not flow. By using the function of the 2-check valve 361, the safety that the movable hook 23 cannot be moved is realized.

When the electromagnetic valve 34 is energized from the first power supply line 42 to the first compartment solenoid 342 by operating the operation switch 45, it is pushed by the first compartment solenoid 342, and the connection relationship of the hydraulic line is removed from the central compartment 343. Switch to first section 341 . Then, when the operation switch 45 becomes neutral 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 the biasing means (for example, a coil spring), and the connection relationship of the hydraulic lines is changed to the first. From 1 section 341 back to central section 343 .

When the electromagnetic valve 34 is energized from the second power supply line 43 to the second compartment solenoid 345 by operating the operation switch 45, the solenoid valve 34 is pushed by the second compartment solenoid 345, and the connection relationship of the hydraulic line is removed from the central compartment 343. Switch to second partition 344 . Then, when the operation switch 45 is turned to neutral 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 the biasing means (for example, a coil spring), and the connection relationship of the hydraulic lines is restored to the second position. From the second compartment 344 back to the central compartment 343 . The central section 343 cuts off the first tank-side hydraulic line 32 and the first cylinder-side hydraulic line 35 and connects the first cylinder-side hydraulic line 35 and the second cylinder-side hydraulic line 36 .

The first section 341 connects the tank-side first hydraulic line 32 and the cylinder-side first hydraulic line 35, connects the tank-side second hydraulic line 33 and the cylinder-side second hydraulic line 36, and connects the tank-side first hydraulic line 32 through the first hydraulic line 35 on the cylinder side to the base end side of the tube of the hydraulic cylinder 231 for hooking, and from the rod side of the tube through the second hydraulic line 37 on the cylinder side and the second hydraulic line 33 on the tank side. Oil is returned to tank 31. As a result, when the operation switch 45 is switched from the central section 343 to the first section 341, the metal block 231 advances (moves to the left in FIG. 2), causing the movable hook 23 to protrude below the pin receiver 214. As shown in FIG.

The second section 344 connects the tank-side first hydraulic line 32 and the cylinder-side second hydraulic line 36, connects the tank-side second hydraulic line 33 and the cylinder-side first hydraulic line 35, and connects the tank-side first hydraulic line 32 through the second hydraulic line 36 on the cylinder side to the rod side of the tube of the hydraulic cylinder 231 for hooking, and from the base end of the tube through the first hydraulic line 35 on the cylinder side and the second hydraulic line 33 on the tank side. Oil is returned to tank 31. As a result, when the operation switch 45 is switched from the central section 343 to the second section 344, the metal block 231 retreats (moves to the right in FIG. 2) and retracts the movable hook 23 from below the pin receiver 214.

The electrical system 4 of this example connects the high voltage side of the first power supply line 42 extending from the operation switch 45 to the first compartment solenoid 342 of the electromagnetic valve 34, and similarly extends the high voltage side of the second power supply line 43 extending from the operation switch 45. is connected to the second compartment solenoid 345 of the electromagnetic valve 34, and the low voltage side of the first power supply line 42 and the second power supply line 43 extending from the first compartment solenoid 342 and the second compartment solenoid 345 are bundled together. The high voltage side of 41 is connected to the tilt switch 46 and the low voltage side of the common feeder line 41 extending from the tilt switch 46 is returned to the operation switch 45 . A power supply 44 is provided on the shared power supply line 41 .

When the operation switch 45 is operated in the energized state of the tilt switch 46 to energize the first power supply line 42, the solenoid 342 for the first section is operated to switch the electromagnetic valve 34 from the central section 343 to the first section 341, and the movable Move hook 23 forward. When the operation switch 45 is operated while the tilt switch 46 is energized to energize the second power supply line 42, the second compartment solenoid 345 operates to switch the electromagnetic valve 34 from the central compartment 343 to the second compartment 344. , retracts the movable hook 23 . When any of the operation switches 45 is operated, unless the tilt switch 46 is energized, the electromagnetic valve 34 cannot be switched, and the movable hook 23 cannot be moved forward or backward.

A procedure for removing the attachment 5 in the attachment attaching/detaching device 2 of this example will be described. In the tilt switch 46 of this example, one end connected to the shared feeder line 41 is in a cut-off state in a tilted posture with an elevation angle (upward tilt angle) above the horizontal, and one end is in a tilted posture with a depression angle (downward tilt angle) below the horizontal. It is a specification that becomes energized at When the center of gravity G of the attachment 5 attached to the attachment attaching/detaching device 2 is on the side away from the movable hook 23 from directly below the center of the fixed hook 22, the tilt switch 46 is in a tilted posture (see FIG. 3) in which one end is depressed. , is attached to the side plate 211 of the arm connecting portion 21 .

In the state of procedure 1 for starting the removal work of the attachment 5, as seen in FIG. It is engaged and sandwiched between the movable hook 23 and the pin receiver 214, and there is no possibility that the attachment 5 will fall unless, for example, the hook hydraulic cylinder 232 inadvertently retracts the hook rod 233. However, since the tilt switch 46 is in a tilted posture with one end at an angle of depression (see the thin solid line arrow in FIG. 3), power can be supplied to the electromagnetic valve 34 through the electric system 4 in the state of procedure 1.

When power is supplied from the second power supply line 43 by operating the operation switch 45 from the state of procedure 1 (see FIG. 3) in which power can be supplied to the electromagnetic valve 34 through the electric system 4, and the solenoid 345 for the second compartment is operated, the electromagnetic valve 34 switches into connection from the central section 343 to the second section 344, and oil is sent through the second hydraulic line 36 for the cylinder to the rod side of the tube of the hydraulic hydraulic cylinder 232 for the hook, and as seen in FIG. The hook 23 can be retracted to the step 2 state (the movable hook 23 is hidden by the side plate 211 and is not shown).

In the state of procedure 2 (see FIG. 4), the attachment 5 is in a state in which the first pin 51 is only engaged with the fixed hook 22 . However, since the center of gravity G of the attachment 5 is on the side away from the movable hook 23 from directly below the center of the fixed hook 22, the attachment 5 is rotated around the first pin 51 that engages with the fixed hook 22 in a direction approaching the movable hook 23. (See the white wavy arrow in FIG. 4) is given, the second pin 52 is pressed against the pin receiver 214, and the first pin 51 does not deviate from the fixed hook 22, so there is a risk of the attachment 5 falling off. no.

Here, when the attachment hydraulic cylinder 13 is operated to retract the attachment rod 131 from the state of procedure 2 (see FIG. 4), as seen in FIG. 5), and one end of the tilt switch 46 is set to the elevation angle (see the thin broken line arrow in FIG. 5), and the state of procedure 3 is reached. The attachment 5 is rotated around the first pin 51 engaged with the fixed hook 22 so that the center of gravity G approaches the movable hook 23 (right rotation in FIG. 5), and the center of gravity G is positioned directly below the center of the fixed hook 22. After that, the rotation is stopped, and only the attachment attaching/detaching device 2 continues to rotate with respect to the attachment 5 whose position is fixed.

In the state of Procedure 3, since one end of the tilt switch 46 is at an elevation angle, power cannot be supplied to the electrical system 4, and the movement of the movable hook 23 by operating the operation switch 45 is restricted. This prevents the movable hook 23 from moving forward and backward inadvertently when the attachment 5 is completely removed from the attachment attaching/detaching device 2 thereafter, and also prevents the attachment attaching/detaching device 2 from being fixed when the attachment 5 is attached to the attachment attaching/detaching device 2 again. The movable hook 23 cannot move forward unless the first pin 51 does not come off the hook 22 in an inclined posture. As a result, the attachment/detachment work of the attachment 5 is carried out in a safe state in which the attachment 5 is prevented from falling off.

From the state of step 3 (see FIG. 5), when the attachment attaching/detaching device 2 is continued to be lifted and the fixed hook 22 is opened downward to take an inclined position, as seen in FIG. 6, the first pin 51 of the attachment 5 is fixed. The hook 22 is released and the attachment 5 is completely separated from the attachment attaching/detaching device 2, resulting in a state of procedure 4.例文帳に追加In this case, if the attachment 5 is grounded on the ground and the attachment attaching/detaching device 2 is lifted upward, the danger of dropping the attachment 5 can be eliminated. Thus, although the attachment attaching/detaching device 2 of the present invention does not have a lock mechanism, the attachment 5 can be safely removed simply by operating the operation switch 45 of the electrical system 4 and changing the tilted posture of the attachment attaching/detaching device 2. be able to.

1 construction machinery
11 Driver's seat
12 arms
13 Hydraulic cylinder for attachment
131 Attachment rod
14 Swing lever
15 link 2 attachment removal device
21 Arm connection
211 side plate
212 Arm connection axis
213 Link connection axis
214 pin receiver
215 arc-shaped slot
22 Fixed hook
23 Movable hook
231 Metal Block
232 Hydraulic Cylinder for Hook
233 Hook Rod
234 Position fixing block 3 Hydraulic system
32 Tank side first hydraulic line
33 Tank side second hydraulic line
34 solenoid valve
35 Cylinder side first hydraulic line
36 Cylinder side second hydraulic line 4 Electric system
41 Common feed line
42 First feed line
43 Second feed line
44 power supply
45 Operation switch
46 Tilt Switch
461 1st fixing bolt
462 2nd fixing bolt 5 attachment
51 1st pin
52 2nd pin G center of gravity

Claims (4)

An attachment that has a fixed hook that engages the first pin of the attachment and a movable hook that moves toward and away from the fixed hook and engages the second pin of the attachment at the arm connection part where the arm, rod or link is connected. In the attachment/detachment device,
1. An attachment attaching/detaching device, comprising: a tilt switch for switching between energization and cut-off depending on a posture; 2. The attachment attaching/detaching device according to claim 1, wherein the electric drive means is a hydraulic cylinder connected to an electromagnetic valve for switching the connection port when the power supply line or the signal line is energized. 2. The attachment attaching/detaching device according to claim 1, wherein the tilt switch is attached to the arm connecting portion in a tilted posture such that the tilt switch is energized when the center of gravity of the attachment attached to the attachment attaching/detaching device is positioned away from the movable hook from directly below the center of the fixed hook. 2. The attachment attaching/detaching device according to claim 1, wherein the tilt switch is attached to the arm connecting portion and has an adjustable tilt position.

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