Safety device for water swivels in construction machinery

Abstract

To provide a safety device of a water swivel for a construction machine which always detects co-rotation and enhances safety.SOLUTION: A scale mounting disk 37 is fixed to the lower part of a coupling 34 by a key 341. An upper end of a drive shaft 24 is screwed and fixed to a male screw 342 on the lower end of the coupling 34. A magnetic scale 4 is stuck and fixed to a cylindrical outer peripheral surface 371 of the scale mounting disk 37 by an adhesive. Accordingly, when drilling work is started and the drive shaft 24 is rotated, a magnetic detection head 44 detects the magnetic scale 4 in a non-contact manner, and can detect a relative rotational frequency between the coupling 34 and an upper head 31A.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a safety device for a water swivel for construction machinery for preventing rotation of the water swivel. More specifically, the present invention relates to a safety device for a water swivel for construction machinery that can detect whether the water swivel rotatably supported on a rotation-driven rod is rotating.

Background Art

[0002] A water swivel used in a boring machine, a ground improvement machine, etc. is attached to the head of a hollow rod for feeding a liquid such as muddy water, clean water, or ground improvement material pressurized by a pump through a hose into the hollow rod driven to rotate. The water swivel is generally composed of a coupling fixed to the upper end of the rotating hollow rod, a head for feeding a liquid from a pressure pump through a hose, a bearing for rotatably supporting the coupling and the head, a seal member for sealing the liquid, and the like. That is, between the head connected to the hose and the coupling fixed to the rotating hollow rod, it is rotatably supported by the bearing, and the gap is sealed with a seal member such as an O-ring or a V-ring so that the pressurized liquid does not leak. However, since the ground improvement material solidifies, the ground improvement material may adhere to and solidify on the bearing and the seal member, or the seal member may deteriorate, causing the coupling and the head to rotate. For this reason, the hose may break or the supply of the pressurized liquid may be interrupted.

[0003] For this reason, many various mechanisms have been proposed to prevent the coupling and the head from rotating (for example, Patent Document 1). In addition, since the deterioration of the seal member is one of the factors causing rotation, a device for predicting the replacement time of the seal member has also been proposed (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] The mechanical anti-rotation devices described in Patent Document 1, etc., do not allow for confirmation of whether or not they are rotating together during actual operation. Furthermore, the wear prediction of seal members, as described in Patent Document 2, does not detect actual malfunctions, and while malfunctions due to the lifespan of seal members can be predicted to some extent, it is unreliable as it cannot address malfunctions caused by other factors. For this reason, maintenance such as cleaning of bearings and seal members, and replacement of seal members due to wear are usually performed periodically, but this management is not easy. The object of the present invention is to provide a safety device for a water swivel in construction machinery that enhances safety by constantly detecting the co-rotation of the water swivel. Another object of the present invention is to provide a safety device for a water swivel for construction machinery that constantly detects the co-rotation of the water swivel, thereby facilitating maintenance management of the water swivel. [Means for solving the problem]

[0006] To solve the aforementioned problems, the present invention employs the following means. In other words, the safety device for a water swivel for construction machinery according to the present invention 1 is a water swivel comprising a leader erected on the construction machinery, a swivel head driven to move up and down along the leader and gripping and rotating a hollow drive shaft, a coupling fixed to the upper part of the drive shaft, a head rotatably supported on the coupling and connected to an injection hose for supplying liquid substance during rotational driving of the drive shaft, a bearing that rotatably supports the coupling and the head, and a seal that prevents leakage of liquid substance between the coupling and the head, wherein the water swivel comprises a drive shaft rotation detection means for detecting the rotation of the drive shaft, a relative rotation detection means for detecting the relative rotation between the coupling and the head, and a water swivel safety control means that calculates the speed difference between the drive shaft rotation speed detected by the drive shaft rotation detection means and the rotation speed detected by the relative rotation detection means, and monitors the operation of the water swivel based on whether the speed difference is within a preset range.

[0007] The safety device for a water swivel for construction machinery according to the present invention 2 is characterized in that, in the present invention 1, the water swivel safety control means performs at least one of the following actions when the speed difference exceeds a preset range: stopping the rotation of the drive shaft, displaying a warning screen, or sounding a warning buzzer. The safety device for a water swivel for construction machinery according to the present invention 3 is characterized in that, in the present invention 1 or 2, the relative rotation detection means comprises a magnetic scale made of a plurality of permanent magnets arranged in a tape shape on the outer circumferential surface of the coupling, and a magnetic detection head arranged on the head for detecting the magnetic scale. The safety device for a water swivel for construction machinery according to the present invention 4 is characterized in that, in the present invention 1 or 2, the relative rotation detection means comprises a plurality of protrusions arranged at equal angular intervals on the outer circumferential surface of the coupling and a proximity sensor arranged on the head for detecting the protrusions. The safety device for a water swivel for construction machinery according to the present invention 5 is characterized in that, in the present invention 1 or 2, the construction machinery is a ground improvement machine that agitates the ground with the drive shaft, or a boring machine that drills holes in the ground. [Effects of the Invention]

[0008] The safety device for a construction machine water swivel of the present invention constantly detects the co-rotation of the water swivel and enables maintenance of the water swivel, thereby facilitating maintenance management of the water swivel and improving the safety of construction machines equipped with water swivels. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an overall side view of a ground improvement machine equipped with a safety device for a water swivel for construction machinery according to an embodiment of the present invention. [Figure 2] Figure 2 is an enlarged longitudinal cross-sectional view of the area around the water swivel attached to the upper end of the drive shaft in Figure 1. [Figure 3] Figure 3 is an explanatory diagram showing a magnetic scale that detects the relative rotation between the coupling and head of the water swivel in Figure 2. Figure 3(a) is a plan view, and Figure 3(b) is a right side view of Figure 3(a). [Figure 4] Figure 4 is a control block diagram of a safety device for a water swivel for construction machinery according to an embodiment of the present invention. [Figure 5] Figure 5 is a flowchart showing the operation of the safety device for a construction machine water swivel according to an embodiment of the present invention. [Figure 6] Figure 6 is an explanatory diagram showing another embodiment of a relative rotation detection means for detecting relative rotation between the coupling and head of a water swivel, where Figure 6(a) is a longitudinal section view and Figure 6(b) is a cross-sectional view AA of Figure 6(a). [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described based on the drawings. Figure 1 is an overall side view of a ground improvement machine equipped with a safety device for a water swivel for construction machinery according to an embodiment of the present invention, and Figure 2 is an enlarged longitudinal cross-sectional view of the area around the water swivel attached to the upper end of the drive shaft in Figure 1. Figure 3 is an explanatory diagram showing a magnetic scale for detecting the relative rotation between the coupling and head of the water swivel in Figure 2. Figure 4 is a control block diagram of the safety device for a water swivel for construction machinery according to an embodiment of the present invention. As shown in Figure 1, the construction machine according to an embodiment of the present invention is a ground improvement machine 1, which has a vehicle body 12 that travels by a crawler device 11, and a columnar leader 13 that is mounted on the vehicle body 12 so as to be able to stand upright and tilt. A swivel head 21 is movably attached to the leader 13 and is raised and lowered by a hydraulic motor 22 at the upper end of the leader 13. A drive shaft 24 is gripped by a drive shaft chuck 23 of the swivel head 21, and the drive shaft 24 is rotationally driven by a rotary motor (not shown). The drive shaft 24 is a hollow pipe, and a stirring blade 25 attached to its lower end stirs and excavates the ground. A water swivel 3 is attached to the upper end of the drive shaft 24, and pressurized liquid ground improvement material is supplied to the drive shaft 24 via the water swivel 3.

[0011] As shown in Figures 1 and 2, an injection hose 32 connected to a pressure pump (not shown) that supplies ground improvement material (liquid substance) is connected to the upper head 31A of the water swivel 3. A plate-shaped connecting member 33 is fixed to the lower surface of the upper head 31A of the water swivel 3 with bolts 311, and the injection hose 32 is held by this connecting member 33. The guide rod 26 is composed of multi-stage stacked telescopic pipes, with the upper end of the topmost (innermost) pipe fixed to the connecting member 33. The lower end of the bottommost (outermost) pipe of the guide rod 26 is fixed to the swivel head 21 with bolts (not shown). This guide rod 26 locks the upper head 31A of the water swivel 3 in place so that it does not rotate together with the rotation of the drive shaft 24 during ground improvement operation.

[0012] A hollow cylindrical lower head 31B is fixed to the lower surface of the upper head 31A with bolts 312, and a hollow cylindrical coupling 34 is rotatably supported inside the lower head 31B by bearings 35A and 35B. A seal 36 is attached to the upper head 31A to prevent leakage of liquid substances between the coupling 34 and the upper head 31A. A scale mounting disc 37 is fixed to the lower part of the coupling 34 with a key 341. The upper end of the drive shaft 24 is screwed into and fixed to a male thread 342 at the lower end of the coupling 34. A magnetic scale 4, as shown in Figure 3, is attached and fixed to the cylindrical outer surface 371 of the scale mounting disc 37 with adhesive. The magnetic scale 4 is formed in a tape shape by bonding rubber magnets 42 to a non-magnetic stainless steel base 41. The rubber magnets 42 are magnetized with alternating north and south poles at equal intervals (for example, 20 mm intervals). The base 41 is 0.3 mm thick and 35 mm wide, and the rubber magnet 42 is 1.6 mm thick and 20 mm wide. As shown in Figure 2, an L-shaped stay 43 is fixed to the lower surface of the connecting member 33, and a magnetic detection head 44 is fixed to the lower end of the stay 43. The magnetic detection head 44 is mounted facing the magnetic scale 4. Therefore, when excavation work begins and the drive shaft 24 rotates, the magnetic detection head 44 can detect the magnetic scale 4 non-contact and detect the relative rotation speed between the coupling 34 and the upper head 31A.

[0013] Figure 4 is a control block diagram of a safety device for a water swivel for construction machinery according to an embodiment of the present invention. As shown in Figure 4, the arithmetic unit 51 is connected to a ROM 52, RAM 53, display device 54, alarm buzzer 55, rotary encoder 56 for drive shaft rotation detection, and detector 57. A magnetic detection head 44 is connected to the detector 57. The detector 57 converts the analog signal from the magnetic detection head 44 into an A / B phase pulse signal. The ROM 52 stores the system program and data. The RAM 53 is loaded with a co-rotation monitoring program 531, a construction support program 532, etc. The co-rotation monitoring program 531 is loaded with a program to monitor the co-rotation of the water swivel 3, display a warning on the display device 54, and sound the warning buzzer according to the rotation speed detection results of the magnetic detection head 44 and the rotary encoder 56 for drive shaft rotation detection. The construction support program 532 is loaded with a construction support program for ground improvement. The arithmetic unit 51 controls the ground improvement machine 1 according to the system program stored in the ROM 52 and the program loaded in the RAM 53.

[0014] Next, the control operation of the safety device for the construction machine water swivel described above will be explained. Figure 5 is a flowchart showing the operation of the safety device for the construction machine water swivel according to an embodiment of the present invention. When the drive shaft 24 rotates after the excavation work is started, first, in step S10, the rotary encoder 56 for detecting the rotation of the drive shaft 24 detects the rotation speed (rpm) of the drive shaft 24. Next, in step S20, the magnetic detection head 44 detects the magnetic scale 4 and detects the relative rotation speed between the coupling 34 and the upper head 31A. Next, in step S30, the rotation speed of the drive shaft 24 is compared with the relative rotation speed between the coupling 34 and the upper head 31A. That is, as the excavation work continues and the ground improvement material supplied to the water swivel 3 solidifies inside the water swivel 3, the coupling 34 and the upper head 31A rotate together, so the relative rotation speed between the coupling 34 and the upper head 31A decreases, resulting in a difference with respect to the rotation speed of the drive shaft 24.

[0015] According to this difference in rotational speed (%), a plurality of warning levels are set in advance. For example, two warning levels, warning level 1 and warning level 2, are set in advance on the rotational speed monitoring screen of the display device 54. For example, warning level 1 is set to 2% for "display warning screen", and warning level 2 is set to 4% for "rotation stop of drive shaft 24", "display warning screen", and "buzzer alarm". Next, in step S40, it is determined whether this difference in rotational speed (%) is below the warning level. If it is below the warning level, the rotation of the drive shaft 24 continues in step S50. If it is above the warning level, it is determined in step S60 whether it is warning level 1. If it is warning level 1, in step S70, a warning screen saying "Abnormal rotation of water swivel detected" and "Please inspect the water swivel" is displayed on the display device 54, and the rotation of the drive shaft 24 continues. If it is warning level 2 in step S60, in step S80, the rotation of the drive shaft 24 is stopped, a warning screen saying "Abnormal rotation of water swivel detected", "Rotation of drive shaft has been stopped", and "Please inspect the water swivel" is displayed on the display device 54, and a buzzer alarm is sounded. The safety device for the water swivel of the construction machine according to the embodiment of the present invention constantly detects the circumferential rotation of the water swivel 3 to perform maintenance on the water swivel. Therefore, maintenance management of the water swivel is easy, and the safety of the construction machine having the water swivel is improved.

[0016] FIG. 6 is an explanatory diagram showing another embodiment of the relative rotation detection means for detecting the relative rotation between the coupling 34 of the water swivel 3 and the upper head 31A. FIG. 6(a) is a longitudinal sectional view, and FIG. 6(b) is a sectional view taken along the line A - A of FIG. 6(a). As shown in FIG. 6, a plurality of convex portions 45 are formed at equal angular intervals on the cylindrical outer peripheral surface 371 of the scale mounting disk 37. Also, a proximity sensor 46 for detecting the convex portion 45 is attached to the lower end of the L-shaped stay 43 fixed to the connecting member 33. Therefore, when the excavation work starts and the drive shaft 24 rotates, the proximity sensor 46 can detect the convex portion 45 in a non-contact manner and detect the relative rotational speed between the coupling 34 and the upper head 31A.

[0017] [Other Embodiments] In the above embodiment of the safety device for the water swivel of construction machinery according to the present invention, although it is applied to a ground improvement machine, it can also be applied to other construction machinery such as a boring machine for drilling the ground as long as it has a water swivel structure.

Explanation of Signs

[0018] 1…Ground improvement machine 11…Crawler device 12…Vehicle body 13…Leader 21…Swivel head 22…Hydraulic motor 23…Drive shaft chuck 24…Drive shaft 25…Agitating blade 26…Guide rod 3…Water swivel 31A…Upper head 31B…Lower head 311, 312…Bolts 32…Injection hose 33…Connecting member 34…Coupling 341…Key 342…Male thread 35A, 35B…Bearings 36…Seal 37…Scale mounting disc 371…Outer peripheral surface 4…Magnetic scale 41…Base 42…Rubber magnet 43…Stay 44…Magnetic detection head 45…Protrusion 46…Proximity sensor 51…Arithmetic unit 52…ROM 53…RAM 531…Circulation monitoring program 532…Construction support program 54…Display device 55…Alarm buzzer 56…Rotary encoder for detecting drive shaft rotation 57... Detector

Claims

1. A leader positioned and mounted on construction machinery, A swivel head is driven to move up and down along the leader and grips a hollow drive shaft for rotational drive, A water swivel comprising a coupling fixed to the upper part of the drive shaft, a head rotatably supported by the coupling and to which an injection hose is connected for supplying a liquid substance during rotational drive of the drive shaft, a bearing that rotatably supports the coupling and the head, and a seal that prevents leakage of the liquid substance between the coupling and the head. In a construction machine having, A drive shaft rotation detection means for detecting the rotation of the drive shaft, Relative rotation detection means for detecting the relative rotation between the coupling and the head, A water swivel safety control means calculates the speed difference between the drive shaft rotation speed detected by the drive shaft rotation detection means and the rotation speed detected by the relative rotation detection means, and monitors the operation of the water swivel based on whether the speed difference is within a preset range. A safety device for a water swivel for construction machinery, characterized by being composed of the following.

2. In the safety device for a water swivel for construction machinery described in claim 1, The water swivel safety control means, when the speed difference exceeds a preset range, performs at least one of the following actions: stopping the rotation of the drive shaft, displaying a warning screen, or sounding a warning buzzer. A safety device for a water swivel in construction machinery, characterized by the following features.

3. In the safety device for a water swivel for construction machinery according to claim 1 or 2, The relative rotation detection means includes a magnetic scale made of multiple permanent magnets arranged in a tape shape on the outer circumferential surface of the coupling, and a magnetic detection head arranged on the head for detecting the magnetic scale. A safety device for a water swivel for construction machinery, characterized by being composed of the following.

4. In the safety device for a water swivel for construction machinery according to claim 1 or 2, The relative rotation detection means includes a plurality of protrusions arranged at equal angular intervals on the outer surface of the coupling, and a proximity sensor arranged on the head for detecting the protrusions. A safety device for a water swivel for construction machinery, characterized by being composed of the following.

5. In the safety device for a water swivel for construction machinery according to claim 1 or 2, The aforementioned construction machine is a ground improvement machine that agitates the ground with the drive shaft, or a boring machine that drills holes in the ground. A safety device for a water swivel in construction machinery, characterized by the following features.

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