JPS6333559B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a depth detection device that is attached to a hard hole drilling machine such as an earth drill or a bucket-type continuous wall machine in which the drilling tool is supported by a wire rope.

For earth drills and bucket type wall machines,
In order to facilitate this repetitive work, since a hard hole is excavated by repeatedly taking earth and sand into a bucket, pulling it up to the ground, and discharging it,
As shown in FIG. 1 for an earth drill, a system is adopted in which a bucket 3 is supported by a crane 1 with a wire rope 2. Note that the bucket 3 is attached to the lower end of the Kelly bar 4, and the Kelly bar 4 is connected to the Kelly bar drive device 6 installed on the front frame 5.
The upper end is connected to the wire rope 2 via a swivel joint 7, and by operating the kelly bar drive device 6, the kelly bar 4 and the bucket 3 (i.e., excavation tool) are
is now being rotated. Further, the wire rope 2 is hung on a sheave 9 at the upper end of the boom 8, and is let out and retracted by a winch 10, so that the bucket 3 can be pulled up and lowered.

In such a pit excavator, the lowering of the bucket is controlled by the brake of the winch 10 so as to reduce the time required for vertical movement of the bucket to take in and discharge soil into the bucket 3. This is often done by a so-called free-haul operation in which the excavator is released and the clutch is released to release the power transmission and the excavator is lowered by its own weight. However, when lowering the bucket through this free hole operation, if the free hole operation was performed continuously until the bucket reached the bottom 11a of the hole 11, the bucket would violently collide with the bottom 11a of the hole, damaging the drilling tool. There is a risk of causing Therefore, conventionally, a depth indicator is provided in the operator's cab to display the depth of the drilling tool, and the operator knows the depth of the drilling tool by looking at the value displayed on the depth indicator, and the operator approaches the hole bottom 11a. At times, the brakes are applied to prevent the drilling tool from colliding violently with the bottom of the hole.

Conventional depth detectors use methods such as rotary encoders, proximity switches, and photoelectronic switches to detect the amount of rotation of the sheave 9, which rotates in proportion to the amount of payout of the wire rope 2 that supports the excavation tool. It is being However, these methods had the following drawbacks. In other words, in the case of a rotary encoder, it is necessary to provide a mechanical transmission mechanism to extract the rotation of the sheave, which poses problems in that care must be taken in maintenance to prevent wear and tear, and the mechanism becomes complicated. Ta.

Further, in the case of a proximity switch, since pulses are generated by cutting off the magnetic field generated by the switch by a proximity body, it is necessary to attach the proximity body as a protrusion to the outer periphery of the sheave.
Therefore, since the installation diameter is larger than the outer diameter of the sheave, the rope stopper, which is installed with a slight gap from the outer diameter of the sheave, must be modified to prevent the rope from jumping out of the groove of the sheave. It was impossible. In order to avoid this, a method can be considered to provide a ring on the side of the sheave and attach the proximate object on this ring, but in this case, it is necessary to separate the proximal object from the side of the sheave to a position where it is not affected by the sheave. The width of the sheave including the sheave became larger, and there was a risk of interference with the adjacent sheave.
Furthermore, the detection surface of the proximity switch is in an environment where iron powder and chips are likely to adhere, which may lead to malfunction. Furthermore, proximity switches generally have a slow response speed and are said to be unable to follow responses of 300 CPS or more, so in order to cope with the fast rotation of the sheave during freehaul, the distance between the proximity switches must be widened to reduce the amount of pulse generation. It was necessary to press the sensor, which caused a problem in detection accuracy.

In addition, in the case of a photoelectronic switch, mounting is restricted because holes are formed in the sheave at equal intervals and a light projector and a light receiver are arranged on both sides of the sheave.

In addition, in the case of so-called non-contact type detectors such as proximity switches and photoelectronic switches, in order to reduce the unit detection length, it is necessary to increase the number of proximal objects in the case of proximity switches and the number of holes in the case of photoelectronic switches. In the former case, the cost of installing the proximal body increases;
The latter case had the disadvantage of reducing the strength of the sheave.

In view of the above-mentioned drawbacks, the present invention provides a depth detection method for a vertical hole excavator, in which the unit detection length can be set smaller than the mounting pitch of a switch driving means that is machined on the sheave side of a proximal body or a sheave hole. With the goal.

Still another object of the present invention is to have a wire rope movement detection means capable of following a fast response during freehaul operation, and to increase the amount of pulses generated per unit length of movement. , it is possible to make the arrangement interval of the switch drive means longer than the unit detection length of the movement amount, thereby reducing the number of switch drive means disposed, improving detection accuracy and reducing costs. The object of the present invention is to provide a depth detection device for a pit excavator using a type switch.

The feature of the depth detection method for a pit excavator according to the present invention is that a plurality of switch drive means are provided at equal intervals in the circumferential direction on the sheave which rotates by the movement of the wire rope supporting the excavation tool, and a plurality of switch driving means are provided at equal intervals in the circumferential direction. By providing a plurality of movement amount detection switches that are operated by the proximity of the switch driving means, when the sheave is rotating in one direction at a constant speed, the plurality of movement amount detection switches are activated to generate pulses at equal time intervals. is generated, and the depth L is determined from the generated pulse, L=p×s/m, where p: pulse generation amount m: wire rope multiplication number s: wire rope movement amount per 1 pulse. However, s= π×D/p ₀ [D: pitch circle of sheave] [p ₀ =e×i e: number of switch driving means i: number of switches for detecting movement amount].

Furthermore, the depth detection device for a pit excavator according to the present invention is characterized by embedding a plurality of permanent magnets in a sheave made of a magnetic material, which is rotated by the movement of a wire rope supporting the excavation tool, except for the surface part. arranged in the circumferential direction, and in a non-rotating part near the sheave,
A plurality of switches for detecting the amount of wire rope movement, which are operated by the proximity of the permanent magnet, are provided so as to operate at equal time intervals when the sheave is rotating at a constant speed.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 2 shows the overall configuration of a detection device including a depth display device for carrying out the method of the present invention, 13 is a movement amount detector for detecting the amount of movement of the wire rope 2, and 14 is a movement amount detector for detecting the amount of movement of the wire rope 2. A moving direction detector 15 for determining whether the wire rope 2 is being let out or retracted is a discrimination circuit that receives a signal from the moving direction detector 14 and determines whether the wire rope 2 is being retracted or retracted. 16 is a calculation device that calculates the depth of the excavation tool; 31 is the movement amount detector 1;
This is a unit length setting device composed of a digital switch that can arbitrarily set the amount of movement of the wire rope 2 per pulse interval of 3, and the arithmetic device 16
is an on/off type digital signal from the movement amount detector 13, a signal from the discrimination circuit 15,
It is configured to receive a signal from the unit length setting device 31 and calculate the depth of the excavating tool. 20
is the calculation device 1 to clarify the depth measurement reference point.
This is a reset button that resets the value of 6 to zero.

The indicator for displaying the depth of the excavation tool may be provided with either a digital indicator or an analog indicator, but in this embodiment, a digital indicator that receives a signal from the calculation device 16 and displays a numerical value is used. A digital-to-analog converter 18 that converts the digital signals from the total 17 and the arithmetic unit 16 into analog signals.
and an analog display meter 19 that receives an analog signal from the digital-to-analog converter 18 and displays the depth.Depth can be recognized by the analog display meter 19 during free hole, and when the excavation tool is stationary, the digital display is provided. With a total of 17 depths, accurate depth reading is possible.

In addition, in this embodiment, in order to reduce the burden on the operator in recognizing the depth of the drilling tool during freehole, the brake operation is performed when the brake operation is required, that is, just before the drilling tool reaches the bottom of the hole, or when the When using a type kelly bar, a device 25 is provided which issues an alarm immediately before each stage kelly bar is fully extended and the retaining protrusions collide with each other, or immediately before the outermost kelly bar (outer kelly bar) collides with the upper part of the kelly bar drive device. ing.

To explain the device 25 for issuing the alarm, 32a, 32b, and 32c are depth setters for setting arbitrary depths such as the depth of the hole bottom and the unit Kelly bar length, and 33a, 33b, and 33c are the depth setters 32a, Comparators 34a, 34b, and 34c receive signals from each comparator and compare whether the depth has become shallower by an appropriate depth l set in consideration of brake operation than the depth L set by 32b and 32c. When the depth of L-l) is reached, the lamps 35a, 35b, 3 corresponding to each depth are
The buzzer/lamp drive circuit instructs the lamps 5c to blink and sounds the buzzer 36, and also instructs the lamps 35a, 35b, 35c corresponding to each depth to turn on when the depth reaches L, and instructs the buzzer 36 to stop. It is.

Therefore, the characteristic part of the present invention is the arrangement method of the movement amount detector 13 and the method of calculating the output, and as shown in FIGS. A plurality of permanent magnets 24 are arranged in the sheave 9 made of a magnetic material at the tip of the magnet 8 at equal intervals in the circumferential direction and partially embedded (except for the surface). A plurality of movement amount detection switches 13a, 13b and movement direction detection switches 14a, 14b, which are activated when the permanent magnet 24 approaches, are spaced apart from each other so as not to come into contact with the permanent magnet. Install it on a non-rotating part.

As is clear from FIGS. 3 and 4, the permanent magnets 24 are arranged in one row on the circumference, and when the switch 13a for detecting the amount of movement is located directly above the permanent magnets 24, the switch is 13b is located between the permanent magnets 24 arranged at equal intervals on the circumference of the sheave 9. Therefore, as shown in FIG. 5, switches 13a and 13b are operated alternately with a non-operation time _T1 . Therefore, by providing two switches for the movement amount detector 13, the permanent magnet 24
The amount of wire rope movement can be detected with an accuracy (unit detection length) of 1/2 of the installation interval. It is clear that if the number of switches in the movement amount detector 13 is increased to 3, 4, or 5, the detection accuracy will be reduced to 1/3, 1/4, or 1/5 accordingly. In addition, in this embodiment, the permanent magnet 2
4 are arranged in one row around the outer periphery of the sheave 9. However, in the case of one row, it is necessary to consider the installation of not only the movement amount detector 13 but also the movement direction detector 14. It is unreasonable to increase the number of devices 13 without limit. Therefore, the detection accuracy can be improved by arranging two or more rows of permanent magnets 24 and adding more switches.

In this embodiment, switches 13a, 13
b, 14a, 14b attached to the bracket 40 is pivotally connected to the shaft 37 of the sheave 9, and the bracket 40 is
0 is attached to a screw seat 38 welded to the boom 8 by fixing it with a bolt 39.
Such switches 13a, 13b, 14a, 1
4b mounting structure, the gaps between these switches and the permanent magnet 24 are inevitably fixed, so errors in assembly are less likely to occur, and the bracket 4
Even if the bolt 39 fixing the switch 0 loosens, the bracket 40 is pivotally attached to the shaft 37, so the permanent magnet 24 and switches 13a, 13b, 14a, 14b
There is no deviation in the gap between the two switches and the relative positions of these switches, and there is no problem with depth detection.

Further, as in this embodiment, by making the outer diameter of the permanent magnet attachment part 50 equal to or smaller than the sheave 9 and the sheave 9' attached coaxially with the sheave 9, the rope 41 hooked thereon can be prevented from slipping. There is no need to modify it into a special shape.

Further, the permanent magnet 24 is embedded in a counterbore portion of a permanent magnet mounting portion 50 integral with the sheave 9, excluding the surface portion, so as to protect it and limit the range in which the magnetic field is generated. Therefore, since the magnetic field is generated only in the vicinity of the permanent magnet 24, the operating time of the switch can be shortened, and the amount of pulse generation per unit of movement can be increased, so the unit length of the movement to be detected can be increased. The length can be shortened.

On the other hand, the switches 14a and 14b constituting the moving direction detector 14 are mounted on the bracket 40 so that one of them operates earlier than the other depending on the direction of rotation of the sheave 9. That is, when the sheave 9 rotates clockwise (wire rope payout direction) in FIG. 3, one switch 14 is turned off as shown in FIG. 6A.
The other switch 14b operates with a delay with respect to the operation of switch 14a, and after a time lapse of _T2 , the operation of switch 14a stops. When the sheave 9 rotates in the counterclockwise direction (wire rope retracting direction) in FIG. 3, the switch 14 is turned on, contrary to A, as shown in FIG.
The switch 14a operates with a delay with respect to the operation of b.
After a time lapse of _T2 , switch 14b is deactivated. In this way, switches 14A, 14b
The direction of movement of the wire rope is determined based on which of the two operates first.

Therefore, the discriminating circuit has switches 14a and 14
It is determined whether the operation of the switch B and the switch B overlap in time, and a comparison is made to see which switch operates faster, and the output signal is changed based on the comparison result.

Further, as shown in FIG. 7, the arithmetic device 16 is composed of an integrating circuit 16a and an arithmetic circuit 16b, and when the output signal of the discriminating circuit 15 indicates wire rope payout, the integrating circuit 16a detects the movement amount detector 13 Each time a pulse is applied, 1 is added to the value stored up to that point; on the other hand, when the output signal of the discrimination circuit 15 represents wire rope renormalization, the value is added every time a pulse is applied. It is configured to perform an operation of subtracting 1. Note that this incorporates a pulse chattering prevention circuit with a large time constant.

The calculation circuit 16b receives the value of the wire rope movement amount S per pulse set by the unit length setting device 31 and performs calculation to convert the value of the integration circuit 16a into the depth of the excavation tool.

The depth L is calculated using the following formula.

L=p×s/m Where, p: Pulse generation amount m: Wire rope multiplication number s: Wire rope movement amount per pulse However, s=π×D/p ₀ [D: Pitch circle of sheave] [ p ₀ = e×i e: number of switch driving means i: number of movement detection switches] The digital display 17 and analog display 19 that display the values calculated thereby are at the zero scale position. On the other hand, the wire rope payout direction is −,
The renormalization direction is displayed as a + sign.

Normally, the setting is zero when the excavation tool 3 such as a bucket is located on the ground surface, so the depth of the excavation hole is displayed as -, and the height when the excavation tool is lifted above the ground is displayed as +. Therefore, the display range of the analog display meter 19 is -
is said to be wider than +.

As shown in FIG. 8, the digital display meter 17 and the analog display meter 19 are installed on the same panel surface of one case 21, and the case 21
It is installed in the instrument panel of the driver's cab as shown at 30 in the figure. The case 21 also includes a power on switch 22.
, the power lamp 23, and the reset button 2.
0, depth setters 32a, 32b, 32c, lamps 35a, 35b, 35c, and a buzzer 36 are attached, and the arithmetic unit 16, the discrimination circuit 15,
Digital-analog converter 18, unit length setter 31, comparators 33a, 33b, 33
c. Buzzer. Lamp drive circuit 34a, 34b, 3
4c is built into the case 21.

Next, the operation of this embodiment will be described.

When the excavating tool is lowered by free hole operation, the operating time relationship of the switches 14a and 14b of the movement direction detector is as shown in FIG.
In order to add
The operation of increasing the value by a (-) value ((-) addition operation) is performed by the pulse from the arithmetic circuit 16.
b converts the integrated value into depth, and the digital value is displayed on the digital display meter 17, and at the same time, the analog quantity obtained by the digital-to-analog converter 18 is displayed on the analog display meter 19. In this case, the value displayed on the digital display meter 17 fluctuates rapidly and is difficult to read, but the depth can be read using the analog display meter 19. Therefore, in the case of an earth drill like this example, the drilling tool is lowered at high speed without applying any brake until it reaches the bottom of the hole, and when the drilling tool approaches the bottom of the hole, the brake is applied to stop it. You can easily land it on the bottom of the hole. This will be explained in detail below. In other words, to determine whether or not the bottom of the hole has been approached, if the previous excavation depth is set in the depth setter 32c, the lamp 35c will flash and the buzzer 36 will start sounding when the depth is shallower by a preset depth l. So you can judge. On the other hand, in the case of a bucket type continuous wall machine, the lamp 35
When C flashes and the buzzer 36 starts to sound, apply the brake to temporarily stop the descent of the excavating tool to avoid unnecessary impact to the bottom of the hole, and then drop the excavating tool again using free hole operation to reach the bottom of the bucket. Dig your nails into the bottom of the hole. In either case, when the bucket is filled with earth and sand, it is pulled up to the ground again, and the value of the depth setter 32c is changed to the depth at this time.

In addition, in the case of earth drills and Kelly-type bucket wall machines, the Kelly bar 4 is usually a multi-stage telescoping type, so as each Kelly bar extends, the protrusions provided on each Kelly bar may catch on each other and fall off. On the other hand, if it is dropped in a free hole, it may collide violently with the protrusion, causing cracks and damage. For this reason, if the operator does not have a depth gauge, he or she applies the brake by checking the amount of unwinding of the winch rope, and even if the operator has a depth gauge, he or she must memorize the depth that is slightly shallower than the engagement part. In addition, there was a risk of misremembering, leading to operational errors. However, since the positions where these protrusions engage are determined, the engagement positions of each stage are set in advance by the depth setters 32a, 32.
If set in b, the lamp 35a will blink at a depth l shallower than the engaging portion, as explained above.
Since the buzzer 36 starts sounding, it is possible to lower the robot slowly while applying the brakes, thereby alleviating the impact at the time of engagement. After engagement, the mode is switched to free hole again, but at this time the lamp 35a turns on to indicate that the initially set depth has been passed, and the buzzer 36 stops sounding. Similarly, even at the depth set by the depth setter 32b, the lamp 35
b and the buzzer 36 operate.

When the excavating tool is pulled up to the ground, the operating time relationship of the switches 14a and 14b of the moving direction detector is as shown in FIG. Therefore, the integration circuit 16a performs an operation of subtracting the value by a (-) value ((-) subtraction operation) using the pulse from the movement amount detector 13.

Normally, the zero reference point for depth is placed on the GL, but when the drilling tool is pulled up from the bottom of the hole and passes through the zero reference point, the internal calculation is a (-) subtraction operation, but the digital Both the display meter 17 and the analog display meter 19 apparently perform a (+) addition operation. For example, if the voltage value when a pulse corresponding to 100 m in absolute value is generated is 10V, then the generated voltage when the reset button 20 is pressed does not return to 0V, and the base voltage value is set to 2V. A voltage of 0 V is generated at a depth of (+) 20 m, and a voltage of 10 V is generated at a depth of (-) 80 m, making it possible to display as described above.

In addition, if the zero reference point of the depth is set on the GL, for example, when the bucket 3 is lowered to the ground with the wire rope 2 stretched, the value displayed on the digital display 17 will change due to the slippage between the wire rope 2 and the sheave 9. Check to see if it is out of order, and if an error has occurred, press the reset button 20 to reset the arithmetic unit 16.

Furthermore, if the value of φD, which is the PCD of the sheave 9 shown in FIG.

As described above, according to the depth detection method of the present invention, the sheave is moved at equal time intervals (the sheave is Since the pulses are generated when the switch is rotating at a constant rotation rate, the amount of movement can be detected using a unit length smaller than the installation interval of the switch drive means, thereby improving detection accuracy. Furthermore, considering the unit length when there is one switch for detecting the amount of movement as a reference, if a plurality of switches are used, the number of switch driving means can be reduced to one part of that number, and therefore, cost reduction can be achieved.

Further, a depth detection device implementing the method of the present invention includes:
Permanent magnets are placed in the circumferential direction by embedding them in a sheave made of magnetic material, excluding the surface area, so the magnetic field is generated only in the vicinity of the permanent magnets, making it possible to shorten the operating time of the switch. Since the amount of pulses generated per unit movement amount can be increased, the unit length of the movement amount to be detected can be shortened, and detection accuracy can be improved.
Furthermore, by providing a plurality of switches for detecting the amount of movement, the number of permanent magnets to be attached can be reduced, and the counterbore process for embedding the permanent magnets can be reduced, thereby achieving a significant cost reduction. In addition, since a switch operated by a permanent magnet has a faster response speed than a proximity switch, it can sufficiently handle free-haul operations and improve work efficiency.

[Brief explanation of the drawing]

Fig. 1 is an overall side view of an earth drill to which the present invention is applied, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is an example of a movement amount detector and a movement direction detector of the embodiment. Layout diagram showing , Figure 4 is the 3rd
5 is a pulse waveform diagram illustrating the operation of the movement amount detector of this embodiment, and FIG. 6 is a pulse waveform diagram illustrating the operation of the movement direction detector of this embodiment. , FIG. 7 is a block diagram showing an example of the configuration of the arithmetic unit and discrimination circuit in this embodiment, and FIG.
The figure is an external view of the display section of this embodiment. 2...Wire rope, 3...Drilling tool, 9...Sheave,
13a, 13b...Movement amount detection switch, 14
a, 14b...Switch for detecting moving direction, 16... Arithmetic device.

Claims (1)

[Claims] 1. A plurality of switch drive means are provided at equal intervals in the circumferential direction on the sheave which rotates by movement of the wire rope supporting the excavation tool, and a non-rotating part is operated by the proximity of the switch drive means. By providing a plurality of movement amount detection switches, when the sheave is rotating in one direction at a constant speed, the plurality of movement amount detection switches generate pulses at equal time intervals. Determine the depth L from the generated pulse, L = p x s/m, where p: pulse generation amount m: wire rope multiplication number s: wire rope movement amount per 1 pulse. However, s = π x D/p ₀ [D : pitch circle of sheave] [p ₀ = e x i e: number of switch drive means i: number of switches for detecting travel distance] Depth detection method for a vertical hole excavator . 2 A plurality of permanent magnets are arranged in the circumferential direction by embedding a plurality of permanent magnets in a sheave made of a magnetic material that rotates with the movement of a wire rope that supports the excavation tool, except for the surface part, and the non-rotating sheave near the sheave The part is characterized in that a plurality of switches for detecting the amount of wire rope movement, which are operated by the proximity of the permanent magnet, are provided so as to operate at equal time intervals when the sheave is rotating at a constant speed. Depth detection device for pit excavators.