JPS63219791A - Safety device for earth drill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a safety device for an earth drill configured to be usable as a crane.

(Prior Art) Figures 12 and 13 show an example of an earth drill that is configured as a crane in its working part and is equipped with an overload prevention device for the crane. An upper revolving body 3 is installed via the revolving device 2, a telescopic boom 5 is attached to the upper revolving body 3 so as to be able to rise and fall freely, and a hoisting winch 6 (chain hoisting winch 6) installed on the upper revolving body 3 consists of a main winding winch 6a and an auxiliary winding winch 6b installed in parallel with the main winding winch 6a.) The kelly rope 7 wound around the main winding winch 6a of the boom 5
A kelly bar 11 is connected to the lower end of the kelly rope 7 via a swivel joint 10, and an earth drill packet 12 is attached to the lower end of the kelly rope 7. The Kelly bar 11 has a rectangular cross section and is inserted into a square hole of a rotating body of the Kelly bar drive device 14 at the end of the front frame 13.
It is attached to a bracket 17 provided at the front of the upper revolving body 3 by a pin 16 so that it can be raised and lowered freely by a hoisting device 15 consisting of a winch, and can be attached and detached together with the Kerry bar drive device 14 and the hoisting device 15. The Kelly bar drive device 14 is supported by the boom 5 via a hanging rope 29.

Also, as shown in Figure 13, during the earth drilling operation,
When used as a crane using the auxiliary winch 6b installed in parallel to the main winch 6a, the front frame 13 is wrapped around the winch of the hoisting device 15, and the auxiliary winch 6b is hung on the sheave 8.9. A hook 21 is attached to the tip of the boom 5 to perform crane work.In order to make this possible, two or more sheaves 8 are installed on the top of the boom 5, and two or more sheaves 9 are installed on the same axis. For example, the Kelly rope 7 is hung around the sheave 8 and sheave 9 on the right side, and the auxiliary winding rope 20 is hung around the sheave 8 and sheave 9 on the left side.

If necessary, a bracket (none of which is shown) having a sheave is attached to the top of the boom 5, and the auxiliary winding rope 20 wound around the auxiliary winding winch 6b is hung on the sheave to perform crane work. Sometimes I do it.

Furthermore, this earth drill has the front frame 13
The kelly bar driving device fi 14 and the hoisting device 15 are removed, and instead of the kelly rope 7, the rope is hooked between a sheave 9, which is a hoisting rope, and a hook block (not shown), and used as a crane.

Further, Fig. 6 shows the work mode selection switch 22 in the conventional overload prevention device, where A is the work mode selected when working with a bracket attached to the top of the boom 5, and B is when used as an earth drill. , or when used as a crane using the main winding winch 6a (
In this case, it is also possible to carry out crane work using the auxiliary winding winch 6a if necessary. ), C is the work mode selected when working with the auxiliary rope 20 when used as an earth drill, and since each has a different rated load, etc. It is selected according to the work mode of the person.

FIG. 2 shows a part of the electric circuit of a conventional overload prevention device, which is a circuit that automatically stops hoisting due to overload. 24 is a solenoid valve inserted in one of the pressure receiving parts of the control valves of the hydraulic motors of the hoisting winches 6a and 6b (that is, the pressure receiving part for hoisting operation), and the solenoid 23a is connected to the overload prevention device. Relay contact 25 that closes with an automatic stop signal from
is connected to the power supply 26 via the control valve, and in the event of an overload, the solenoid valve 23 is switched from the right position to the left position as shown in the figure by closing the relay contact 25, so that the operating pressure of the pressure receiving part for hoisting operation of the control valve is reduced. It is configured to either wind up or stop automatically depending on the tank pressure.

In such an earth drill, as shown in FIG. 6, the B position of the work mode selection switch 22 of the overload prevention device is set when used as an earth drill and when used as a crane using the main winding winch 6a. Since it is also used as a work mode for ground drills, the following malfunctions occur when used as a ground drill.

(1) After the excavation work is completed, when the packet 12 is pulled up as shown in Fig. 12, the space a between the packet 12 and the bottom of the hole 27 becomes a vacuum state, the load increases temporarily, and the overload prevention device is activated. The relay contact 25 shown in FIG. 2 is activated, the solenoid valve 23 is switched to the left position, and the hydraulic motor for the first hoisting winch is stopped.

(2) Also, when pulling out the packet 12, the Kerry bar 11
The upper end of the auxiliary winding rope 20 is supported by the rope 30 from the top of the boom 5.
28, the overwinding prevention device stops, and the hydraulic motors commonly installed in the auxiliary winding winch 6a and the main winding winch 6b also stop, so that hoisting is stopped.

Such malfunctions frequently occur when pulling up the packet 12, and even when the packet 12 is rotated and excavated, the overload prevention device is activated due to the vibrations and shocks caused by the excavation, and the overload prevention device is automatically activated when unnecessary. There are times when it stops.

Since the earth drill will not fall when the packet 12 is inside the hole 27, stopping the winding due to the overload prevention operation does not contribute to improving safety, but only causes a decrease in efficiency.

Therefore, it is possible to provide a release mechanism that stops the operation of the overload prevention device during earth drilling work, but when switching to crane work using the auxiliary hoisting winch 6b, the operator can continue the crane work with the overload prevention device released. There is a danger of doing so.

(Problems to be Solved by the Invention) In view of the above problems, the present invention provides a grounding system that can improve work efficiency during excavation work and that does not reduce work safety during crane work. The purpose is to provide safety equipment for drills.

(Means for solving the problem) In order to achieve this object, the present invention provides an earth drill equipped with an overload prevention device for a crane, which is provided with an automatic stop release switch for canceling the automatic stop caused by the overload prevention device. In addition, the present invention is characterized in that an automatic return device is provided for deactivating the automatic stop release switch during crane work using a main winding winch or during crane work using an auxiliary winding winch during earth drilling work.

In addition, by providing the automatic stop release switch with a function that not only cancels the automatic stop caused by the overload prevention device but also the automatic stop caused by the overwinding of the auxiliary winding rope, it is possible to prevent the overloading of the auxiliary winding rope during earth drilling work. It is possible to prevent winding from stopping due to winding switch activation.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an electric circuit diagram showing an example of an overload prevention circuit in a hoisting circuit of the present invention. In this embodiment, a relay contact 25 activated by a signal emitted at the time of overload in an overload prevention device and an automatic hoisting circuit are shown. Stop solenoid valve 2
An automatic stop release switch 30 and a switch 31 that closes in conjunction with the engagement of the auxiliary clutch lever are connected and inserted in parallel between the solenoid 23a of No. 3 and the solenoid 23a.

The automatic stop release switch 30, as shown in FIGS. 3 and 4,
The locking tool 34 for locking the telescopic lever 33 is attached to be opened or closed depending on whether it is in a lock-on state or a lock-off state.

That is, the stand 35 is placed near the lever 32, 33.
, attach the shaft 36 to the stand 35, and attach the shaft 36 to the stand 35.
A cylindrical body 37 is rotatably fitted into the cylindrical body 37, a U-shaped locking tool 34 is attached to the cylindrical body 37, and the locking tool 34 is connected to the lever 32, 33 as shown by the two-dot chain line a in FIG. When it is in the retracted position, press lever 3 as shown by the arrow in Figure 4.
2.33 is free to move and the contacts of the switch 30 are closed, or the locking tool 34 is turned and the lever 32.33 is closed, as shown by the solid line in FIGS. 3 and 4.
If the levers 32 and 33 are pinched, movement in the direction of the arrow is blocked, and the striker 38 attached to the cylindrical body 37 presses the operating rod 30a of the switch 30, causing the switch 30 to be pinched.
It changes from a closed state to an open state.

According to this embodiment, during the earth drilling operation.

Since the boom hoisting lever 32 and the boom telescoping lever 33 are not operated, these levers 32 and 33 are locked to prevent erroneous operation as shown in FIGS. 3 and 4, and the striker 38 pushes the operating rod 30a. Since the contact of the switch 30 is open, even if the overload protection device is activated and the relay contact 25 is closed, the automatic stop solenoid valve 23 will not switch and will not stop automatically.On the other hand, the front frame 13 When performing crane work using the main winding winch 6a after removing the Kerry bar 11, etc., the boom hoisting lever 32 and boom telescoping lever 3
3, the locking tool 34 is
Since the lock is always released in the retracted position shown in a in the figure, the automatic stop release switch 30 is closed, and when the overload prevention device is activated and the relay contact 25 is closed, the automatic stop solenoid valve 23 is closed. The winding is automatically stopped.

Therefore, as the lever is locked and unlocked at the same time as the earth drilling work and crane work are recombined, the overload prevention device 1F is automatically and reliably turned on and released, and the overload prevention device is activated by the operator. There is no need for turning on or turning off.

Further, the auxiliary clutch lever interlock switch 31 connected in parallel to the automatic stop release switch 30 is closed when switching from earth drilling work to crane work using the auxiliary winch 6b, and when the auxiliary winch 6b is used. This is done in consideration of the fact that crane work is performed without necessarily extending and contracting or raising and lowering the boom 5.

The auxiliary winding clutch lever transmits or releases the rotation of a drum driven by a hydraulic motor shared with the main winding winch 6a to the drum of the auxiliary winding winch 6b. As shown in FIG. 5, the auxiliary clutch lever 40 is rotatably mounted around a shaft 41.
A rod 42 connected to a clutch (not shown) on the tail end side of the
It becomes by concatenating. The auxiliary clutch lever interlock switch 31 is provided near the rod 42, and the switch 31 is open when the auxiliary clutch lever 40 is in the non-operating position, as shown in FIG. When performing crane work using the auxiliary winch 6b, tJ
The lever 40 is operated as shown by the arrow C in the SS diagram, but at this time the striker 43 attached to the rod 42 moves as shown by the arrow d and the actuating rod 31 of the switch 31 is moved.
Press a to close the contact of switch 31.

Therefore, when the overload prevention device is activated and the relay contact 25 is closed during hoisting by the auxiliary hoisting winch 6b, the automatic stop solenoid valve 23 is switched and the hoisting is automatically stopped.

Furthermore, when switching between earth drilling work and crane work using the auxiliary winding winch 6b, the overload prevention device is automatically engaged and released in conjunction with the operation of the clutch lever 40. , there is no need for the operator to turn on or release the overload prevention device.

In addition, as shown by the dotted line in Figure 1, a relay contact 90 is provided in parallel with the contact 25 activated by the overload prevention device, which is activated by the overwinding switch 2 for detecting overwinding of the auxiliary rope. For example, it is possible to prevent winding from stopping due to malfunction of the overwinding switch during earth drilling work.

FIGS. 7 and 8 show other embodiments of the present invention; conventionally, the positions that can be selected by the work mode selection switch 22 are 6 (three positions A, B, and C as shown in A). , B positions are designed to be used both when used as an earth drill and when used as a crane using the main winding winch 6a.
, C, B is dedicated to the earth drill, and D is set to the crane work mode using the main winding winch 6a.

Further, when the work mode selection switch 22 is set to the D position and crane work is performed, the automatic stop release relay 44 is energized and its contact 44a is closed, as shown in FIG.

Therefore, in this embodiment as well, when the operator operates the work mode selection switch 22 at the start of work, the overload prevention device is automatically turned on or off. Furthermore, when performing crane work using the auxiliary winding winch 6b during earth drilling work, as explained in the previous embodiment, the auxiliary winding clutch lever interlock switch 3
1 is closed, the winding operation is automatically stopped in the event of an overload.

91A to 11 are other embodiments of the present invention,
: In the JS9 figure, 61 is the main body of the overload prevention device, which includes a load detector 62 provided at the connection part of the boom 5 to the boom 5 of the hydraulic cylinder 4 for hoisting, a boom length detector 63, and a boom length detector 63. Each output of the angle detector 64 is input,
Performs the necessary calculations, compares the results with internally stored values, and if there is an overload, relay unit 5
A solenoid valve 66 (actually, a plurality of solenoid valves are installed) is inserted into the pilot circuit of each control valve so that the buzzer 65 sounds and the hoisting, boom extension, and boom lowering are stopped depending on the situation. (only one is shown).

Reference numeral 51 denotes a control device provided in accordance with the present invention, including an automatic stop release switch 55 for canceling automatic stop and alarm generation by the overload prevention device, and a reset switch 56 for restoring the released automatic stop and alarm generator te. and,
A lamp 57 is provided that lights up when the automatic stop or alarm generation function is canceled.

A sensor 53 is inserted into the operating circuit of the boom hoisting lever 32 and operates by detecting the operating pressure, and a sensor 54 operates by detecting the operating pressure of the front frame hoisting device 15. These sensors 53 and 54 may be provided in the drive circuit instead of the operation circuit.

FIG. 10 is a circuit diagram showing the control device 51 and relay unit 58 shown in FIG. 9. Reference numeral 25 indicates a contact point of a sensor that closes in response to a signal from the overload prevention device body 61 in the event of an overload, and 70 to 76 indicate switching transistors. Now, when the sensor contact 25 closes during an overload, the transistor 70 turns on, the buzzer 65 sounds, and the solenoid valve 66 operates to stop hoisting, boom lowering, or boom extension. Further, when the contact 25 closes, a current flows through the circuit 78 having the capacitor 77, so that the base current flows through the transistor 71, turning on the transistor 71, and thereby the circuit 79
A current flows through the transistors 71 and 72, causing the base potential of the transistors 72 to rise and turning on the transistors 72. At the same time, the base current of the transistor 1 flows through the transistors 72, so that even if the contacts 25 are open, these transistors 71. 72 remains on.

While transistors 71 and 72 are on, the collector of transistor 71 is connected to the base of transistor 73 and 74 via diode 80 and 81 and resistors 82 and 84, respectively. , preventing these transistors 73, 75 from turning on.

When performing earth drilling work, when the automatic stop release switch 55 is operated and closed, a base current flows to the transistor 73 via the resistor 82 and the capacitor 85, and the transistor 74 is turned on based on the same principle as described above.
Keep it on. In this case, transistor 73
transistor 7 through the collector of transistor 86
By being connected to the base of transistor 0, the base potential of transistor 70 is pushed up, turning off the transistor 70, regardless of whether the sensor contact 25 is open or closed.
The solenoid valve 66 does not operate, and the buzzer 65 does not sound.

On the other hand, when the reset switch 56 is operated and closed, the transistor 75 is turned on via the capacitor 87 and the limit switch 56, and the transistor 76 is also turned on and maintained in the on state by the same principle as the circuit described above. Further, the collectors of the transistors 75 are connected to the transistors 71 .
Since it is connected to the base of transistor 73,
By turning on the transistors 71 to 74, the transistors 71 to 74 turn off. Thereby, when the contact 25 is closed, the transistor 70 is turned on, and an operation for overload prevention is performed.

Further, for the limit switch 56, a contact 53a of a sensor 53 that operates by detecting the operating pressure of the boom hoisting lever 32, a contact 54a of a sensor 54 that operates by detecting the operating pressure of the front frame hoisting device 60, etc. Since they are connected in parallel, when transitioning from earth drilling work to crane work using the auxiliary winding winch 6b, the front frame 13 must be raised, so closing the sensor contact 53a is the same as operating the limit switch 56. The overload prevention +i- device becomes operational. Furthermore, even when performing crane work without raising the front frame 13, the angle of the boom 5 must be changed because the Kerry bar 11 obstructs the work radius in the excavation position and the crane work cannot be performed. Since the contact point 54a is closed, the overload prevention device is also enabled to operate. The above operation is repeated in the 11th
This is shown in the time chart in the figure.

Although the above embodiments have been described with reference to the case where the boom 5 is a telescopic boom, the present invention can also be applied to a case where the boom 5 is a non-retractable boom. The present invention can also be applied to the configuration.

(Effects of the Invention) As described above, in the present invention, since a switch for canceling the automatic stop caused by the overload prevention device is provided, during earth drilling work, the automatic stop release switch operates.
Even if the overload prevention device malfunctions, it will not automatically stop.1
Work efficiency can be improved.

Also, crane work using a main winding winch.

Alternatively, when crane work is being performed using an auxiliary winding winch during an earth drill, a device is provided that automatically returns the automatic stop release switch, which prevents erroneous operation due to incorrect switching of the automatic stop release switch, resulting in safety.

In addition, by providing the automatic stop release switch with the function of canceling not only the automatic stop caused by the overload prevention device but also the automatic stop caused by overwinding of the auxiliary rope, it is possible to prevent the auxiliary rope from being stopped during ground drilling work. It is possible to prevent the winding from stopping due to the operation of the winding switch, and further improve work efficiency in earth drilling work.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing an embodiment of the safety device according to the present invention, Fig. 2 is an electric circuit diagram showing a conventional safety device, and Fig. 3 is a lever of an automatic stop release switch in the embodiment of Fig. 1. FIG. 4 is a side view showing the operating mechanism attached to the locking device, FIG. 4 is a side view of A-AItlr in FIG. 3, and FIG. 6 is a side view showing the operating mechanism, FIG. 6 is a diagram showing a conventional work mode selection switch, FIG. 7 is a diagram showing a work mode selection switch according to another embodiment of the present invention, and FIG. An electrical circuit diagram related to the embodiment, FIG. 9 is a device configuration diagram showing another embodiment of the present invention, FIG. 1O is a partial electrical circuit diagram of the embodiment, and FIG. 11 shows the operation of FIG. 1O. An explanatory time chart, FIG. 12 is a side view showing an example of a conventional earth drill, and FIG. 13 is a side view showing a crane working state iB using an auxiliary winding winch.

Claims (1)

[Scope of Claims] 1. An earth drill equipped with an overload prevention device for a crane is provided with an automatic stop release switch for canceling the automatic stop caused by the overload prevention device, and is also equipped with an automatic stop release switch for canceling the automatic stop caused by the overload prevention device. A safety device for an earth drill, comprising an automatic return device that deactivates the automatic stop release switch during crane work using an auxiliary winding winch during drilling work. 2. The earth drill has a telescoping boom, and the automatic return device is configured to interlock with a boom hoisting lever and a locking device for the boom telescoping lever. Earth drill safety device. 3. The earth drill has a work mode selection switch, and has a circuit that automatically operates the automatic stop release switch and automatic return device according to the work mode selected by the work mode selection switch. A safety device for an earth drill according to claim 1, characterized in that: 4. The earth drill has an auxiliary winding clutch lever that transmits the rotational force of the hoisting hydraulic motor to the auxiliary winding winch drum, and the automatic stop release switch is linked to the engagement and release of the auxiliary winding clutch lever. The safety device for an earth drill according to claim 1, characterized in that the safety device has a configuration that switches the safety device according to claim 1. 5. The automatic return device is comprised of a pressure sensor of an operation circuit or a drive circuit of the front frame hoisting device and a pressure sensor of an operation circuit or drive circuit of the boom hoisting lever. Safety device for the earth drill described in item 1. 6. An earth drill equipped with an overload prevention device for cranes is equipped with an automatic stop release switch that cancels the automatic stop caused by the overload prevention device and the automatic stop caused by overwinding of the auxiliary rope, and the crane is equipped with a main winding winch. 1. A safety device for an earth drill, comprising an automatic return device that deactivates the automatic stop release switch during crane work using an auxiliary winding winch during earth drill work.