JPS6329078B2 - - Google Patents

Description

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

For earth drills and bucket type wall machines,
In order to make this repetitive work easier, since a pit 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 hooked onto a sheave 9 at the upper end of the boom 8 and repeatedly retracted by a winch 10, thereby raising and lowering the bucket 3.

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 that displays the depth of the drilling tool is installed in the operator's cab, and the operator knows the depth of the drilling tool by looking at the value displayed on the depth indicator, and the operator knows the depth of the drilling tool by checking the value displayed on the depth indicator. When approaching, the brakes are applied to prevent the drilling tool from colliding violently with the bottom of the hole.

However, according to this conventional technology, when performing a free hole, it is necessary to remember the previous excavation depth, and also to determine and memorize the depth at which the brakes should be applied, which is several meters shallower than the previous excavation depth. ,
Misremembering caused an erroneous operation, and the machine was inevitably damaged by the impact. Also as Kerryba,
In a vertical hole drilling machine using a multi-stage telescopic kelly bar, in addition to the previous excavation depth, the values that should be used for freehole are the values when the retaining protrusion of each stage kelly bar engages, and the retaining value of the outermost kelly bar. In order to reduce the impact when the protrusion for the Kerry bar is engaged with the Kerry bar drive device, the engaging position of the Kerry bar must be memorized. Because I have to keep an eye on them, the workload is also heavy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a depth detection device for a pit excavator, which is free from the risk of erroneous operations as described above and can reduce the burden on the operator.

To achieve this objective, the present invention provides a depth detection device for a pit excavator in which a drilling tool is supported by a wire rope, including a depth indicator that indicates the depth position of the drilling tool, and an arbitrary depth that can be set. a depth setter, a comparator that compares the actual depth of the excavation tool with a depth that is arbitrarily set shallower than the depth L set on the depth setter, a warning lamp or buzzer, and the excavation tool. The apparatus is characterized in that it is further provided with a drive circuit that operates the lamp or buzzer when the comparator issues a signal indicating that the depth is (L-l) during descent.

Further, the present invention is characterized in that the device having a multi-stage kelly bar is provided with a plurality of the depth setting devices and comparators so that an alarm is issued even when the kelly bar is engaged.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 2 shows the overall configuration of the detection device including the depth display device, 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 whether the wire rope 2 is being paid out or not. A moving direction detector 15 is a discrimination circuit that receives a signal from the moving direction detector 14 and determines whether the wire rope 2 is let out or retracted. 16 is a calculation device that calculates the depth of the excavation tool; 3
Reference numeral 1 denotes a unit length setting device constituted by a digital switch that can arbitrarily set the amount of movement of the wire rope 2 per pulse interval of the movement amount detector 13; 13
The depth of the excavating tool is calculated by receiving an on/off type digital signal from the excavator, a signal from the discrimination circuit 15, and a signal from the unit length setting device 31. 20 is a reset button for setting the value of the calculation device 16 to zero in order to clarify the depth measurement reference point.

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 19 that receives an analog signal from the digital-to-analog converter 18 and displays the depth.During free hole, the analog display 19 enables depth recognition, and when the digging tool is stationary, the digital An indicator 17 allows accurate depth reading.

Therefore, in the present invention, in order to reduce the burden on the operator in recognizing the depth of the drilling tool during freehole, brake operation is required when the drilling tool reaches the bottom of the hole, or when the brake is operated in multiple stages. When using a type Kerry bar, just before each stage of Kerry bar is fully extended and the retaining protrusions collide with each other,
Alternatively, a device 25 is provided which issues an alarm immediately before the outermost kelly bar collides with the upper part of the kelly bar drive device. The illustrated example is applied when the Kelly bar is a multi-stage telescopic Kelly bar, and 32a, 32b, and 32c are depth settings that set arbitrary depths such as the depth of the bottom of the hole, which is the previous drilling depth, and the unit Kelly bar length. Vessel, 33a, 33b, 3
3c is a depth (L-l) that is shallower than the depth L set by the depth setters 32a, 32b, and 32c by an appropriate depth l (about several meters) set in consideration of brake operation, and a depth (L-l) from the calculation device 16. Comparators 34a, 34b, 34 for comparing with the actual depth
c receives the signal from each comparator (L-
When the depth of l) is reached, turn on the lamp 3 corresponding to each depth.
In addition to instructing lights 5a, 35b, and 35c to flash and sounding the buzzer 36, when the depth reaches L, the lights 35a, 35b, and 35c corresponding to each depth are activated.
This is a buzzer/lamp drive circuit that instructs the buzzer 36 to turn on as well as instructs the buzzer 36 to turn off.
Note that the buzzer only sounds when the excavation tool 3 is descending.
In order to enable the lamp drive circuits 34a to 34c to operate, for example, the comparators 33a to 34c are activated only when the output of the discrimination circuit 15 indicates a drop.
33c or buzzer/lamp drive circuit 34a-3
All you have to do is make 4c work.

Next, the movement amount detector 13 and the movement direction detector 1
4 and the specific configuration of the arithmetic unit 16, the detectors 13, 14 are switches 13a, 13b and 14a, 14b operated by permanent magnets.
The case will be explained with reference to FIGS. 3 to 7.

As shown in FIGS. 1, 3, and 4, a ring 50 made of a magnetic material is integrally provided on the side surface of the sheave 9 at the tip of the boom 8 on which the wire rope 2 is hung. A plurality of permanent magnets 24 are disposed on the outer periphery of the magnet 50 at equal intervals in the circumferential direction and partially embedded (except for the surface). and movement amount detection switches 13a and 13b that operate when the permanent magnet 24 approaches;
The moving direction detecting switches 14a and 14b are mounted on a non-rotating part near the sheave with a space between them so as not to contact the permanent magnets.

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
If the mounting structure of bracket 4b is used, the gaps between these switches and the permanent magnet 24 are unnaturally fixed, so errors in assembly are less likely to occur, and the bracket 4b is
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, the outer diameter of the ring 50 is
By making the sheave 9 or the sheave 9' attached coaxially with the sheave 9' to be equal to or smaller than the sheave 9, there is no need to modify the retainer 41 of the rope hanging thereto into a special shape.

As mentioned above, if the structure is such that the permanent magnet 24 is embedded in the ring 50 made of magnetic material and the switch is operated by the permanent magnet, the magnetic field is
, the permanent magnet 24 can be installed close to the permanent magnet 24, and the switch opening/closing response speed by the permanent magnet 24 is fast, and a response of up to 1000 CPS is possible.
Although a detection device with high detection accuracy can be realized, in this embodiment, in order to obtain higher detection accuracy, a ring 50 with a permanent magnet 24 provided on one side of the sheave 9 is used.
They are arranged in two rows on the outer periphery of the . In addition, sheave 9
One row of permanent magnets may be arranged on each side of the magnet. Furthermore, although the mounting intervals of the permanent magnets 24 in the same row are equal, the mounting intervals of the permanent magnets in different rows are relatively shifted by half a pitch to prevent mutual interference between the permanent magnets in different rows. Switches 13a and 13b for detecting the amount of movement are arranged in different columns, and when switches 13a and 13b are on one permanent magnet 24 in one column, switch 1
3b and 13a are attached to the bracket 40 so as to be located between the two permanent magnets in the other row.

Therefore, as shown in FIG.
The switches 13a and 13b are operated alternately by wrapping the operating time _T1 , and the switches 13a and 13b
The total number of pulses obtained by the operation of the wire rope becomes a signal indicating the amount of movement of the wire rope.

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 in response to the operation of switch a, and after a time lapse of _T2 , switch 14a
operation stops. When the sheave 9 rotates in the counterclockwise direction (wire rope retracting direction) in FIG. 3, switch 1 is turned
The switch 14a is activated with a delay with respect to the activation of the switch 4b, and after a time lapse of _T2 , the operation of the switch 14b is stopped. In this way, the switches 14a, 1
The moving direction of the wire rope is determined depending on which of the wire ropes 4b is activated first. Therefore, the discrimination circuit determines whether the operations of the switches 14a and 14b overlap in time, compares which switch operates faster, and changes the output signal based on the comparison result. There is.

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×n×s/m where p: Amount of pulse generation per one revolution of sheave 9 n: Amount of rotation of sheave 9 s: Amount of wire rope movement per one pulse s=πD/p [D: Amount of sheave 9 pitch circle] (See Figure 3) m: Wire rope multiplier The digital display meter 17 and analog display meter 19, which display the calculated value, indicate the wire rope feeding direction with respect to the zero scale position. −, the renormalization direction is displayed as +. 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 wider for - than for +.

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 buzzer 36 are attached, the arithmetic unit 16, discrimination circuit 15, digital-to-analog converter 18, unit length setter 31, and comparator 33a. , 33b, 33c,
and buzzer/lamp drive circuits 34a, 34b,
34c 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. That is, 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 comparator 33c outputs a signal at a depth that is shallower than this by a preset depth l, and the drive circuit 34c outputs a signal. This can be determined because the lamp 35c flashes and the buzzer 36 starts beeping. On the other hand, in the case of a bucket-type continuous wall machine, when the lamp 35c flashes and the buzzer 36 sounds as described above, the brake is applied to prevent the excavator from descending once to avoid unnecessary impact to the bottom of the hole. After stopping, the drilling tool is lowered again using free hole operation, and the hook of the bucket digs into the bottom of the hole. In either case,
When the bucket is filled with soil, it will be pulled up to the ground again, but the depth setter 3 will be set at the depth at this time.
Change the value of 2c.

In the case of earth drills and Kelly type bucket wall machines, the Kelly bar 4 is usually a multi-stage expandable type, so as each Kelly bar extends, the protrusions provided on each Kelly bar hook with each other to prevent them from falling out. 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. There was also a risk of misremembering, leading to operational errors. However, since the positions at which these protrusions engage are fixed, if the engagement positions of each stage are set in advance using the depth setters 32a and 32b, as explained above, the depth will be lower than the engagement position.
The lamp 35a flashes and the buzzer 36 starts to sound at a shallow depth, that is, at a depth that takes into account the braking operation, so it is possible to lower the vehicle slowly while applying the brakes, thereby alleviating the impact at the time of engagement. After engagement, the switch is again made to the free hole mode, but at this time the lamp 35a turns on to indicate that the cutest set depth has been passed, and the buzzer 36 stops sounding. The lamp 35b and buzzer 36 are activated in the same way even at the depth set by the depth setting device 32b.
works.

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 G and L, but when the drilling tool passes through the zero reference point when being pulled up from the bottom of the hole, the internal calculation is a (-) subtraction operation. However, both the digital 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, but 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.

Also, if the zero reference point of depth is placed on G and L,
For example, with wire rope 2 stretched, bucket 3
When the machine is lowered to the ground, check whether the value displayed on the digital display meter 17 is out of order due to slippage between the wire rope 2 and the sheave 9. If an error has occurred, press the reset button 20 and reset the arithmetic unit. 16
Reset.

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

Note that the present invention is not limited to the above embodiments, and various changes and additions can be made without departing from the gist of the present invention. For example, as the detectors 13 and 14, other switches such as a proximity switch, a photoelectronic switch, an ultrasonic switch, or a semiconductor device can be used in addition to the present embodiment, and the detection part of the wire rope movement is also limited to the sheave. First, it may be a winch, and if the winch is used for detection, the amount of movement may be detected in consideration of the number of layers of wire rope. It is also possible to detect the amount of movement by attaching an encoder to the winch or sheave.

Further, a switch operated by an operator is provided in place of the moving direction detector 14 and the discrimination circuit 15 provided for instructing the arithmetic unit 16 to perform addition and subtraction.
Addition or subtraction may be performed by switching the switch.

As described below, in the present invention, the previous excavation depth can be set and the alarm is generated at a depth several meters shallower than the previous excavation depth. This eliminates the hassle of searching and memorizing depth information and the need to carefully stare at the depth indicator during free holes, reducing the operator's workload. Moreover, by providing a plurality of depth detectors and comparators, when using a multi-stage telescopic Kerry bar, the operator's workload can be further reduced to a large extent.

Further, according to the present invention, it is possible to prevent damage to the machine due to shocks caused by erroneous operations due to troublesomeness or erroneous memory.

[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, 17...Digital display meter, 19...Analog display meter, 32a-32
c...depth setter, 33a-33c...comparator, 34a-34c...buzzer/lamp drive circuit,
35a-35c...Lamp, 36...Buzzer.

Claims (1)

[Claims] 1. A depth detection device for a pit excavator in which a drilling tool is supported by a wire rope, including a depth indicator that indicates the depth position of the drilling tool, and a depth setting device that can set an arbitrary depth. , a comparator that compares the actual depth of the excavation tool with a depth that is arbitrarily set shallower than the depth L set in the depth setting device, a warning lamp or buzzer, and a warning lamp or a buzzer; A depth detection device for a vertical hole excavator, comprising a drive circuit that operates the lamp or buzzer when a comparator issues a signal indicating that the depth is (L-l). 2. A depth detection device for a pit excavator that has a multi-stage kelly bar and in which the excavation tool is supported by a wire rope, which includes a depth indicator that indicates the depth position of the excavation tool, and a plurality of depth indicators that can set arbitrary depths. a depth setter, and a plurality of comparators that compare the actual depth of the excavation tool with a depth that is arbitrarily set by a depth l shallower than the depth L set in each of the depth setters;
A pit characterized by being provided with a warning lamp or buzzer, and a drive circuit that operates the lamp or buzzer when the comparator issues a signal indicating that the depth is (L-l) when the excavation tool is lowered. Depth detection device for excavators.