KR20010087218A - Safety equipment for working vehicle - Google Patents

Abstract

PURPOSE: To prevent a telescopic arm from suffering a damage accident due to excessive expansion and to enable an operator to understand situations by informing the operator of the deepest location in a working process of expanding the telescopic arm to the deepest location. CONSTITUTION: In a multistage telescopic type working machine provided with a multistage telescopic arm expanded by an expansion operation hydraulic cylinder, at least two types of objects to be detected 21, 22 with different conditions are arranged on different location of a moving side of a cylinder body constructing an expansion arm 11. The device is constructed in such a manner as to make an operator recognize an operating stage of the telescopic arm 11 by combinations of signals send by sensors 23, 24 arranged on a stationary side and detecting the objects to be detected 21, 22.

Description

Extension arm safety device of multi-stage telescopic work machine {SAFETY EQUIPMENT FOR WORKING VEHICLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work machine for a construction machine having a multistage telescopic arm, and in particular, a bucket attached to the distal end of the multistage telescopic arm reaches the deepest position at the time of work. The present invention relates to an extension arm safety device of a multistage telescopic working machine which informs an operator to perform work safely.

Conventionally, in a hydraulic shovel having a multistage work arm that can be stretched, it is stretched in multiple stages by a telescopic means composed of a combination of a hydraulic cylinder and a wire rope to stretch the work arm. A work was carried out by extending the excavated soil from a deep position into a clamshell bucket that was extended by a working arm of the equation. In this operation, if the operator does not recognize that the cram shell bucket of the work arm tip is grounded and further extends the work arm or performs another operation, the operator may perform an inefficient vacant work. Overloading the support will cause damage.

As a measure to prevent such unreasonable work, for example, as disclosed in Japanese Patent Application Laid-Open No. 11-270505, a stroke composed of an upward detection sensor, a downward detection sensor, and a position detecting convex part on an extension arm. A stroke detector mechanism is provided so that the detection signal from the sensor is outputted when entering the deceleration zones set at both ends of the expansion and contraction operation. In the hydraulic control unit to control, when the expansion arm enters the deceleration area of the administrative end from the lower stroke, the switching pressure reducing valve of the control unit is switched to the decompression position by a detection signal from the lower detection sensor. In addition, it is described that the expansion speed of the telescopic hydraulic cylinder is reduced to alleviate the shock when stopping at the stroke end.

In the prior art which proposes the safety measures of the present invention, it is effective to reduce the impact by reducing the stretching speed at the end of the extension, to reduce the impact. However, there is a problem that an operator cannot accurately grasp the deepest position. Therefore, the kidney is stopped in the state that the extension arm has not reached the end of the kidney, and in the invisible state, it becomes impossible to shake the anxiety of working depending on the movement of the machine.

The present invention has been made in order to solve the above-described problems, while preventing the damage caused by excessive load in the arm stretched state in advance, and at the same time the process of stretching the stretched arm to the deepest position at work It is an object of the present invention to provide an extension arm safety device for a multi-stage telescopic working machine in order to inform the operator of its deepest position and extension of the extension arm.

1 is a perspective view of a construction machine provided with a multistage telescopic working machine of the present embodiment.

FIG. 2: is a figure (a) which shows the expansion / contraction detection part in an extension arm, and the detail view (b) of the P part in the figure.

3 is an electric circuit diagram for operating the notification means.

4 is a diagram illustrating an example of a notification monitor.

5 is a view showing an example of the deep drilling operation by a multi-stage telescopic working machine.

Fig. 6 is a block diagram schematically showing the operation principle in the extension operation of the extension arm.

7 is an operation state diagram (1) of the notification means operation electric circuit.

8 is an operation state diagram (2) of the notification means operation electric circuit.

9 is an operation state diagram 3 of the notification means operation electric circuit.

10 is an operation state diagram 4 of the notification means operation electric circuit.

11 is an operation state diagram 5 of the notification means operation electric circuit.

Fig. 12 is a hydraulic operation circuit diagram of a hydraulic drive hydraulic cylinder for expansion and drive linked with the deepest position detection by the expansion and contraction detection means.

Fig. 13 is a hydraulic operation circuit diagram of the hydraulic cylinder for expansion and drive driving linked with the deepest position detection by the expansion and contraction detection means.

14 is a diagram showing a control method of another embodiment.

15 is a diagram showing another embodiment of the object to be detected in the stretch detection means.

Fig. 16 is an exemplary view in which a safety valve capable of adjusting a set pressure is provided in a drive hydraulic cylinder.

Fig. 17 is an exemplary embodiment in which a safety valve capable of adjusting a set pressure is provided in a drive hydraulic cylinder.

[Explanation of symbols for the main parts of the drawings]

1: base machine 2: boom 6: cab

10: multi-stage telescopic working machine 11: telescopic arm 12: base arm (base arn)

13: top arm 14: second arm

16: hydraulic cylinder 17: extension wire rope

20: expansion and contraction detection means 21, 22, 21A: the detected object

23, 24, 23a, 24a: sensor 26: attachment bracket of sensor

28: buzzer release switch 30: notification means 32: monitor box

40: control section of the hydraulic cylinder 42: operation circuit 43: foot pedal

44: hydraulic switching valve 45, 45 ': electromagnetic shut-off valve

48: damper 50: operation laser

51, 52: relief valve (safety valve) 55: driving hydraulic mechanism of expansion arm

RL1, RL2, RL3, RL4: relay

B1, B2, B3: Alarm Buzzer L1, L2, L3: Indicator Lamp

In order to achieve the above object of the present invention, the expansion arm safety device of a multi-stage telescopic work machine according to the first invention,

In a multistage telescopic working machine having a multistage telescopic arm that is telescopically stretched by a telescopic hydraulic cylinder, at least two types of inspected bodies having different conditions on the moving side of the cylindrical body constituting the telescopic arm. It is characterized in that the operation stage of the telescopic arm is distinguished by a combination of signals which are arranged at different positions, and which detect and transmit the detected object by a sensor provided on the stationary side. . (Invention described in claim 1)

In addition, the safety device for a multistage telescopic work machine according to the second invention is a multistage telescopic work machine having a multistage telescopic arm that expands and contracts by a telescopic hydraulic cylinder,

Combination of detection signals which are attached to the telescopic arm and detect the movement of the detected object installed on the movable side by the sensor provided on the stationary side, and the elastic detecting means which can identify the operation stage of the telescopic arm, It is configured to feed back the signal detected by the extension detecting means to the drive control part of the extension arm so that the braking force is applied to the operation input part of the drive hydraulic mechanism of the extension arm if the set condition is met. It features. (Invention described in claim 4)

In addition, the telescopic arm safety device of the multistage telescopic working machine according to the third invention is a multistage telescopic working machine having a multistage telescopic arm that is telescopically stretched by a telescopic hydraulic cylinder, which can identify the operation stage of the telescopic arm. In the multi-stage telescopic working machine having a multistage telescopic arm provided with a detecting means and a drive control unit of the telescopic arm to which the detecting signal of the telescopic detecting means is input,

A relief valve is provided in the drive hydraulic mechanism of the expansion arm which can change the set press ure in response to a command signal from the drive control unit, and the drive control unit in the step of setting operation. And a command signal for changing the set pressure by the signal input from the expansion and contraction detecting means to the always relief valve. (Invention described in claim 6)

(Example)

Specific embodiments of the extension arm safety device of a multi-stage telescopic work machine according to the present invention will be described with reference to the drawings.

Figure 1 is a perspective view of a construction machine is installed a multi-stage telescopic working machine of the present embodiment. Fig. 2 shows a drawing (a) showing the stretch detection section in the stretchable arm and a detailed view (b) of the P section in the drawing, and an electric circuit diagram for operating the notification means in Fig. 3, respectively.

The multi-stage telescopic work machine 10 of the present embodiment is an arm (hereinafter referred to as an telescopic arm 11) that extends and contracts at the tip of the boom 2 of a crawler-driven base machine 1 (in this example, a hydraulic excavator). The rear end of the base arm 12 of the base arm 12 is pinned and mounted, and the rod end portion of the arm cylinder 3 installed on the upper portion of the boom 2 is connected to the upper rear part of the base arm 12 so that the boom ( Relief rotation is possible at the tip of 2). In addition, a cram shell bucket 15 is installed at the lower end of the extension arm 11 to be used for deep drilling work. The boom 2 is undulated by the boom cylinder 4 and operated in the cab 6 mounted on the upper swinging body 5.

The extension arm 11 in the multistage telescopic work machine 10 includes a base arm 12 supported by a boom 2 of the base machine 1 and a multistage in the base arm 12. It consists of a top arm 13, a second arm 14, and a telescopic driving mechanism provided therein. Then, the hydraulic drive mechanism for expanding and contracting the expansion drive mechanism and the hydraulic clamshell bucket 15 are mounted, and these hydraulic devices are hydraulically piped from the base machine side 1 by known means. In addition, each part of the extension arm 11 is supported by sliding freely by well-known means.

The telescopic drive mechanism is a telescopic hydraulic cylinder (hereinafter, simply referred to as a hydraulic cylinder 16) having a required stroke for supporting the rear end portion of the saw arm 13 and supporting and mounting the piston rod end portion with the second arm 14. And an extension-side wire rope 17 and a loose-side wire rope 17 'which interlock with the expansion-contraction operation of the hydraulic cylinder 16 to expand and contract the whole.

In the extension arm 11 of such a structure, the extension detection means 20 which can identify the operation step of the extension arm 11 is provided in one side part. The extension detecting means 20 has a required width and a suitable length that are arranged in parallel in the axial direction at one side in the middle of the second arm 14 of the extension arm 11. The branches are opposed to the moving axes of the two to-be-detected bodies 21 and 22 and the two to-be-detected bodies 21 and 22 attached to the second arm 14 at a predetermined position on the base arm 12. It consists of two contactless sensors (hereinafter, simply referred to as sensors 23 and 24). And it is provided with the notification means 30 provided in the cab 6 so that an operator may be notified and recognized the operation step of the expansion arm 11 detected by the expansion-detection means 20. As shown in FIG.

The two arms 21, 22 move the second arm 14 when one of the two objects 21 extends in length from the contracted position to the maximum stroke. It has a length dimension slightly shorter than the length to be provided, and is provided to be located inside the section from the most contracted state to the most extended state. Moreover, the other to-be-detected body 22 shortened the length dimension rather than the said to-be-detected body 21, and as shown in FIG. The other end is provided so that an appropriate amount of the other end is extended from the end of the other to-be-detected body 21 to the rear end side (upper side at the time of use).

Moreover, the sensors 23 and 24 which detect the movement of the said to-be-detected body 21 and 22 are made into proximity, without touching the upper surface of the to-be-detected body 21, 22, and the place of the base arm 12 is in place. The distal end is fitted into the mounting hole 25 provided in the mounting hole 25, and is attached by the attachment bracket 26. The above-described detection bodies 21 and 22 and the sensors 23 and 24 corresponding thereto can be installed so that any one mounting position can be adjusted. In this way, for example, when the operation stroke (stroke) of the telescopic arm 11 is largely changed, the position of the detected object can be adjusted to correspond to the sensor side. On the contrary, when the detection bodies 21 and 22 are fixedly installed, the positions of the sensors 23 and 24 can be moved to adjust the position.

As shown in Fig. 3, the notifying means 30 is provided in the notifying portion provided in the cab 6 of the base machine 1 of the expansion and contracting means 20 provided on the expansion arm 11 side. Two sensors 23 and 24 are connected electrically. The sensors 23 and 24 are connected to the alarm buzzers B1, B2 and B3 and the display lamps L1, L2 and L3 through the relays RL1 to RL4, so that the display lamps are operated in accordance with the operation stage of the expansion arm 11. At the same time, the alarm buzzer sounds and the operator is notified. In the drawing, reference numeral 27 denotes a wire rope abnormal sensor, 28 denotes a buzzer release switch for stopping the buzzer sound, and 29 denotes a power supply.

The display lamps L1, L2, L3 and the alarm buzzers B1, B2, B3 in the notification means 30 are, for example, as shown in the figure showing an example of the notification monitor in FIG. L2, L3 and alarm buzzers B1, B2, and B3 are integrated into the monitor box 32 installed in the cab 6 in an easy-to-recognize position at the front of the cab 6. It is arranged. These display lamps L1, L2, and L3 are yellow for display lamp L1 indicating the deepest notice indicating that the nearest position is reached, for example, the deepest signal indicating that the deepest position is reached. The lamp L2 indicating the warning is red and the lamp L3 indicating the abnormality of the wire rope is also made red so that identification is easy. The alarm buzzers B1, B2, and B3 have different buzzer sounds according to their respective situations, and can be discriminated.

Next, in the present embodiment, as shown in the drawing showing an example of the deep drilling work by the multi-stage telescopic working machine in Fig. 5, the safety device described above for the expansion arm 11 in the multistage telescopic working machine 10. The operation of the safety device configured as described above will be described with respect to the case in which.

First, when the expansion arm 11 operates the hydraulic cylinder 16 in the extending direction by the operator's instruction operation, the top arm 13 on which the hydraulic cylinder 16 is mounted is operated by the known operation. ) Advance me. As a result, a sheave 18 which is attached to the rear end of the second arm 14 with the tension acting on the extension-side wire rope 17 supported by the base arm 12 at one end thereof. The second arm 14 is pushed through, and the extension arm 11 is extended.

In this way, when the expansion and contraction arm 11 is extended, the sensing bodies 21 and 22 placed on one side of the second arm 14 move, and the sensor 23 placed on the base arm that is always kept in the stopped state. The detection bodies 21 and 22 are detected by 24, and the detection signal is transmitted to the notification means (monitor box 32) installed in the cab 6 by an electric circuit that operates the notification means 30, and operates. Each step is notified, and the operator is notified of the status of the operation to control the decompression operation.

Here, the operation of the present embodiment will be described in more detail with reference to Fig. 6, which is a block diagram schematically showing the operation principle in the extension operation of the extension arm.

In the state before the expansion arm 11 starts the extension operation by the hydraulic cylinder 16 (first step), the expansion arm 11 is in the shortest state, and the base arm 12 is positioned on the base arm 12. Since the sensors 23 and 24 mounted on the sensor are in a state away from the sensing bodies 21 and 22 placed on the second arm 14, the detection signal is not emitted. This state is shown in Fig. 6A. In addition, the state in which the sensor in this FIG. 6 is a white circle shows non-operation, and the state of a black circle shows operation. In this state (first step), as shown by the operation state diagram 1 of the notification means operation electric circuit in Fig. 7, the sensors 23 and 24 are not operated, and the relays RL1 to RL4 are all turned off ( In the off state, the notification means 30 does not operate.

Then, when the hydraulic cylinder 16 is driven to move the expansion and contraction arm 11 to the extension operation, the second arm 14 moves forward as the saw arm 13 moves forward. Then, one to be detected 21 is detected by the sensor 23. This state is shown in Fig. 6 (b). And this state continues until the extension arm 11 reaches the deepest position vicinity. In this operation step, as shown in the operation state diagram 2 of the notification means operation electric circuit in Fig. 8, the relay RL1 is operated by the detection signal of the sensor 23, and the alarm buzzer B1 in the notification means 30 is operated. At the same time, the display lamp L1 lights up. Therefore, the operator can see that the expansion arm 11 has reached the deepest position near the monitor box 32, so that the operator moves to the state of stopping the extension operation of the hydraulic cylinder 16.

In addition, when the expansion arm 11 continues to move forward, the operation step proceeds to the next step. That is, when the expansion arm 11 reaches the deepest position, the other sensor 24 along with one sensor 23 detects the movement of the other object 22 (a state shown in FIG. 6C), Both sensors 23 and 24 transmit detection signals. In this operation step, as shown in the operation state diagram 3 of the notification means operation electric circuit in Fig. 9, the relays RL1, RL2, and RL3 are operated by the detection signals of the sensors 23 and 24 to provide the detection means 30 to the detection means 30. Alarm buzzer B2 sounds, and the indication lamp L2 lights up at the same time. At this point, when the indicator lamp L2 is displayed in red and the alarm buzzer B2 is beeping loudly with a "beep beep" sound, the operator is alerted and quickly stops the extension of the hydraulic cylinder. 11) can be prevented from extending further. As a result, by overextending, not only the expansion arm 11 can be damaged, but also anomalies such as anomalous external force acting on other parts can be prevented in advance, thereby preventing the accident and securing the safety.

Next, as shown in Fig. 6 (d), when the expansion arm 11 is further advanced through the deepest position when the extension arm 11 is extended, the movement of one of the objects 21 corresponds to When the sensor 23 is in an undetected state and only the other sensor 24 is in a state in which the sensing object 22 is detected, an operating state diagram of the electric circuit of the notification means operation in Fig. 10 is shown in Fig. 10. As shown in FIG. 5, the relays RL1, RL2, and RL3 stop operation, and only the relay RL4 is in an operating state, and the alarm buzzer B3 sounds, and at the same time, the display lamp L3 lights up to cause the wire rope 17 to relax. The operator can be notified to call attention. In this case, if the buzzing sound of the alarm buzzer B3 is given a continually beeping sound, for example, beeping, and the display lamp L3 is turned on in red, the operator can identify the emergency situation and promptly. It is effective as a warning to stop operation.

In this way, if the wire rope is loosened, the new arm 11 passes through the deepest position and may overoperate, leading to an accident. Therefore, the operator quickly stops the extension arm 11 from extending. When the excavating work of the excavated soil is stopped and the wire rope 17 on the extension side is turned in the contracting direction, the loosening of the wire rope can be corrected and returned to the normal state, and subsequent work is safely performed. You can do it.

Fig. 11 shows an example of a case where a disconnection accident occurs in the electric circuit by the operation state diagram 5 of the notification means operation electric circuit. In this figure, the state when the disconnection generate | occur | produced in the connection circuit of the sensor 23 is shown. In the event of such a disconnection accident, the notification means 30 is operated regardless of the respective operation steps to notify the operator of the accident. In the event of disconnection among the circuits connecting the sensor 23 and the notification means, the relay RL1 is operated irrespective of the operation step to activate the alarm buzzer B1 and the display lamp L1, respectively. In addition, even when the sensor 24 or the circuit connecting the sensor 27 and the notification means 30 is disconnected, the corresponding relays operate to cause the alarm buzzer to ring and the indicator lamp to light up, and the corresponding operation is performed. Notification is made by the notification means 30 irrespective of the steps, and it is urged to prompt the operator to respond to and restore the disconnection accident in the circuit.

Next, an embodiment in which more effective control can be performed in addition to the above embodiment will be described. In this embodiment, the expansion detecting means 20 detects the operation stage of the expansion arm 11 so as to notify the notification means 30 of the operation state of the expansion arm, and at the same time operates the hydraulic cylinder by the operator. Direct control, and means to more reliably recognize the extension motion to the deepest position of the extension arm.

12, the hydraulic operation circuit diagram of the expansion / extension drive hydraulic cylinder which interlocks with the deepest position detection by a expansion / extension detection means is shown.

In this embodiment, as described above, the sensors 23 and 24 in the extension detecting means 20 of the extension arm produce a detection signal in which the extension arm 11 reaches the deepest position. The sensor 23 in conjunction with the alarm of the alarm buzzer B2 reaching the deepest position and the lighting of the display lamp L2, as described above, by the operation of the relays RL1, RL2, and RL3. , The detection signal by 24 is transmitted to the control part 40 of the hydraulic cylinder. On the other hand, a control circuit for connecting the foot operation pedal 43 and the hydraulic switching operation valve 44 to the hydraulic cylinder 16 to the operation circuit 42 of the hydraulic mechanism for operating and operating the hydraulic cylinder 16. The electromagnetic shutoff valve 45 is provided on the extending operation side a of the expansion arm 11, and the expansion arm 11 is the deepest by the command signal from the control unit 40 of the hydraulic cylinder. When the position is reached, it is associated to shut off.

Therefore, when the expansion arm 11 reaches the deepest position, the expansion detection means 20 of the expansion arm notifies the notification means 30 of the effect, and is in the control circuit of the hydraulic cylinder 16. A control signal is sent to the electromagnetic shutoff valve 45 provided in the pilot circuit a on the stretch operation side, and the electromagnetic shutoff valve 45 is shut off to stop the stretching operation of the hydraulic cylinder 16. In this way, the movement of the hydraulic oil in the pilot circuit a is stopped by the blocking operation of the operation pedal 43, which is closed by the operator, in the extension operation direction by the extension operation side a. As a result, the sounding operation cannot be performed, and the operator can stop the stretching operation of the extension arm 11 bodily. In the figure, reference numeral b denotes a pilot circuit on the contraction operation side, 46 a hydraulic pump, and 47a and 47b are pilot operation valves operated by the operation pedal 43.

13 shows another example of the hydraulic operation circuit diagram of the hydraulic drive hydraulic cylinder for expansion and drive linked to the deepest position detection by the expansion detection means.

The other embodiment shown in this figure is basically the same as the above embodiment, but the solenoid shutoff valve 45 'and the damper 48 actuated by the control signal emitted from the control unit 40 have a foot pedal ( It is comprised so that the operation force of the pedal operation attached directly to the extension operation side of the foot pedal 43 may be changed. Therefore, the same code | symbol is attached | subjected about the same or same thing as the said Example, and description is abbreviate | omitted.

In this embodiment, when the deepest position detection signal of the extension arm 11 is issued by the expansion and contraction detection means 20, the effect is transmitted to the notification means 30 and notified, and at the same time, the control unit 40 of the hydraulic cylinder A signal is transmitted from the sensors 23 and 24, and a control signal is given to the electromagnetic shutoff valve 45 ′ from the control unit 40. Then, the electromagnetic shut-off valve 45 'is actuated and shut off, and the oil pressure in the pilot circuit is directed to the receiving side 48a of the damper 48 provided on the extension operation side of the foot pedal 43. Is sent, and even if the operator tries to push the operation pedal 43 to the extension operation side, the operation force increases until then, and the staping operation becomes remarkably heavy. As a result, the operator feels that the operation has become difficult, and further, the operation of stopping the operation on the extension operation side is stopped. In other words, it feels that the expansion arm 11 has reached the deepest position, stops the stretching operation, and can end in a safe state without performing excessive operation. Therefore, the hydraulic switching control valve 44 returns to the neutral state, and the oil supply to the extending side of the hydraulic cylinder 16 is stopped.

In this way, in conjunction with the deepest position detection of the expansion and contraction arm 11 by the expansion and contraction detection means 20, a means for applying the braking force to the operating force portion to the hydraulic supply operation portion (foot pedal 43) to the hydraulic cylinder is provided. By notifying the operator not only to change the operation stage to ventilate the operation, but also to feel it directly, the extension arm of the extension arm can be stopped more reliably in the deepest position to not cause excessive movement. It can prevent the unnecessary movement and the unforeseen accidents caused by it. In addition, although the above description relates to operating the hydraulic cylinder by the foot pedal, the same effect can be obtained by adding the same mechanism even when performed by the operation lever instead of the foot pedal.

14 is a view showing a control method of another embodiment. This embodiment is basically the same as the structure of the above embodiment but differs in part. Therefore, the same reference numerals as those of the above embodiment will be omitted for the same or same parts as the above embodiment.

In this embodiment, the extension detecting means 20 of the extension arm is the same as the above embodiment, and the second arm on the extension arm is formed by the two detection bodies 21 and 22 on the extension side and the detection object on the contraction side. When the displacement is detected by the sensors 23 and 24, the detection signal is sent to the control unit of the control circuit 40A of the hydraulic cylinder, and the vicinity of the end of the expansion and contraction of the extension arm 11 is detected, and the hydraulic switching operation to the hydraulic cylinder 16 is performed. The electromagnetic switching valve 45a provided in the expansion operation side a in the pilot circuit for operating the valve 44 is operated to stop the operation by the expansion side pilot operation valve 47a of the operation lever 50. . In this case, the lever operation in the operation lever 50 becomes heavy, and an operator can be physically urged to stop expansion operation.

Moreover, in the process of contracting and contracting the expandable arm 11, when the sensor 24 or 23 detects 21 A of the to-be-detected body provided in the side end part of the retractable side of the second arm 14, a control circuit The contraction operation side (b) in the pilot circuit for operating the hydraulic pressure switching operating valve 44 to the hydraulic cylinder 16 while the detection signal is sent to the controller of the 40A and the expansion arm 11 is close to the contraction end. ), The electromagnetic switching valve 45b provided therein is operated to stop the operation by the contraction side pilot operation valve 47b of the operation lever 50. In this case, the lever operation in the operation lever 50 becomes heavy, and the operator is urgently urged to stop the contraction operation.

By doing so, the state detection at both ends of the expansion and contraction arm 11 can be performed, and in any case, it is possible to safely perform the desired operation without excessively operating the hydraulic cylinder.

Next, in FIG. 15, the figure which shows another Example of a to-be-detected body in a stretch detection means is shown. As shown in this figure, one bar-shaped member can be used as the object to be detected, so that different types of detection signals can be sent to notify the status. 21 A of the to-be-detected body of this Example is formed in two steps, and the sensor provided in the opposing stop side (base arm 12) has two types of proximity sensors of which a sensitivity differs, and the movement axis of the second arm 14 is carried out. It is arranged in series with respect to. Then, using the sensor 23a capable of detecting only a very close position and the sensor 23a capable of detecting a range up to the required far position, the sensor (a) at the low position 21a of the target object 21A is used. 23a) is detected, and it detects by the sensors 23a and 24a in the high position part of the to-be-detected body 21A, and it is comprised so that it can detect from the above-mentioned operation step 1st to 3rd (deepest position). . In this manner as well, the above-described effects can be obtained.

16 shows an exemplary embodiment in which a safety valve capable of adjusting the set pressure is provided in the drive hydraulic cylinder. In this embodiment, as shown in the drawing, if the control unit 40 that receives the detection signal of the extension detecting means 20 (refer to Fig. 2) by identifying the operation stage of the extension arm matches the setting condition, the command is given. The setting pressure of the safety valves (relief valves) 51 and 52 connected to the bottom side and the rod side of the arm driving hydraulic cylinder 16 in the driving hydraulic mechanism 55 of the expansion arm in response to a signal is changed. Thus, damage to the extension arm and its drive mechanism can be avoided.

In this example, when the extension detecting means 20 detects the approach or reach of the deepest position (see Fig. 5) of the cram shell bucket 15 provided at the tip of the extension arm 11, the arm drive is used. The set pressures of the relief valves 51 and 52 connected to the bottom face side and the rod side of the hydraulic cylinder 16 are lowered to a predetermined pressure. In this state, if an excessive load is applied to the extension arm in the tension direction and the compression direction, the pressure is released by the relief valves 51 and 52 to avoid damage to the extension arm and its driving mechanism. As the relief valves 51 and 52 which change the said set pressure, you may use the relief valve which is a hydraulic pump in the drive-hydraulic mechanism 55 of a telescopic arm, as shown in FIG. Or if the multistage telescopic work machine is installed on the upper swing body of the vehicle, it goes without saying that the same function can be obtained even if the function is added to the brake valve of the hydraulic swing motor.

In the telescopic arm safety device of the multistage telescopic working machine of the present invention, at least two types of inspected bodies having different conditions are arranged side by side at a preset position on the cylindrical body of the movable side constituting the telescopic arm. Correspondingly, a sensor is installed on the stationary side, and the extension arm reaches the vicinity of the deepest position in the contracted state by a combination of detection signals detected by the sensor by the operation of the extension arm. Each operation step, such as the state, the state where the deepest position is reached, and the state where relaxation is occurring in the wire rope, can be identified by the control unit and notified by the operator so as to be recognized.

This allows the operator to recognize the operating state of the telescopic arm, in particular in its previous state that the bucket has reached its deepest position, so that preparations for stopping the operation are carried out so that work can be performed without excessively extending the telescopic arm. Will be.

In addition, when the extension arm extends beyond the intended deepest position, it can be seen that the wire rope is loosening and can be corrected before the accident occurs. Therefore, the operator can be always notified of the operation status of the extension arm, and the effect of preventing accidents and failures without any excessive work by calling attention is obtained.

In the first aspect of the invention, it is preferable that the object is arranged side by side in the axial direction of the cylindrical body of the telescopic arm and shifted in the front-back direction, and the sensor is placed on the stationary side of the telescopic arm in correspondence with the above-described respective body. . (Invention described in claim 2) In this way, the operator sees and recognizes an identification signal in a predetermined operation step by sending different signals by two sensors in response to movement of the expansion arm, and combining the detection signals in the control unit. By notifying the position where possible, it is possible to obtain an effect that the status judgment can be made quickly. In addition, it is preferable that the identification signal be provided with means which can be easily recognized by the lighting of the lamp and the ringing of the buzzer.

The sensor and the object to be detected are preferably mounted so that any one position can be adjusted in a positional relationship with each other. (Invention of Claim 3) In this way, it becomes possible to cope with the change of the extension | stretching conditions of an extension arm. Therefore, it is possible to set the optimum condition for the state of the construction, and there is an advantage that the economical operation can be performed without wasting equipment.

Moreover, the to-be-detected body may arrange | position in series what differs in the sensitivity by a sensor. In this case, for example, a step is set on the object to be detected, and a sensor having a different sensitivity is disposed on the sensor to be opposed to each other. By transmitting, the above-described effects can be obtained.

According to the second invention of the present application, the extension arm is provided with expansion and detection means consisting of a sensor and a corresponding sensor capable of detecting the extension state on the extension arm, so that the operation step of the extension arm can be identified by the detection signal; At the same time, the detection signal is fed back to the drive control unit in the drive hydraulic mechanism of the extension arm, for example, when the step before the extension arm reaches the deepest position is detected, the drive hydraulic pressure in the drive control unit of the drive hydraulic mechanism is detected. The hydraulic circuit to the cylinder is tightened, the braking force is added to the movement of the operation pedal by the operator or the operation lever that extends the expansion arm by the operator, and the operation force is changed to take a measure to make the movement heavy. It can be detected and warned that the extension of the extension arm is just before the limit. As a result, it is possible to recognize the end of the operation, thereby preventing the extension of the extension arm excessively, it is possible to obtain the effect that safe driving is possible.

A shut-off valve is provided in the switching operation circuit of the stretch operation valve in the drive hydraulic mechanism of the expansion arm, and the shut-off valve is operated by a signal input in a set operation step. It is preferable to be configured to stop the stretching operation by the hydraulic cylinder. (Invention according to claim 5) In this way, if the set operation step is close to the stroke end of the hydraulic cylinder, the hydraulic cylinder can be prevented from rapidly reaching the stroke end, thereby ensuring safety. It can work.

According to the third aspect of the present invention, a relief valve in which a set pressure can be changed in a hydraulic pipeline to the rod side and the bottom side of the hydraulic cylinder for driving is provided. By changing (lowering) the set pressure of those relief valves with a command signal, the effect of preventing overload can be obtained.

In addition, a multistage telescopic working machine having a multistage telescopic arm that is telescopically stretched by a telescopic hydraulic cylinder, the telescopic arm means for identifying the operation stage of the telescopic arm, and the telescopic arm into which the detection signal of the telescopic sensing means is input. In the multi-stage telescopic working machine provided with the multistage telescopic arm provided with the drive control unit of

And a notifying means for notifying the arm operating step in accordance with the output signal from the drive control unit. In this way, the operation stage of the extension arm can be recognized by the notification means provided in close proximity to the operator's driving position, so that the situation can be easily understood and no waste can be caused in the operation operation. . In addition, risks can be recognized in advance, enabling safe driving.

Claims (7)

In a multistage telescopic working machine having a multistage telescopic arm that is telescopically stretched by a telescopic hydraulic cylinder, at least two types of inspected bodies having different conditions on the moving side of the cylindrical body constituting the telescopic arm. The controller is configured to identify the stage of operation of the telescopic arm by a combination of signals which are arranged at different positions and are detected and transmitted by a sensor provided on the stationary side. Extension arm safety device of multi-stage telescopic working machine. The multistage telescopic work machine according to claim 1, wherein the inspected body is arranged side by side with respect to the axial direction of the cylindrical body of the telescopic arm, and is shifted in the front-back direction, and the sensor is placed on the stationary side of the telescopic arm corresponding to each of the inspected bodies. Extension arm safety device. The telescopic arm safety device according to claim 1 or 2, wherein the sensor and the object to be detected are mounted so as to be able to adjust their position in a relative positional relationship. In the multi-stage telescopic working machine provided with the multistage telescopic arm telescopic by the telescopic hydraulic cylinder, Combination of detection signals attached to the extension arm and detecting the movement of the object to be installed on the movable side by the sensor on the stop side, and having elastic extension means for identifying the operation stage of the extension arm. The signal detected by the detecting means is fed back to the driving control part of the expansion arm, and if the setting condition is met, the braking force is applied to the operation input portion of the driving hydraulic mechanism of the expansion arm. Extension arm safety device of a multi-stage telescopic work machine. The shut-off valve according to claim 4, wherein a shut-off valve actuated by a command signal from the drive control unit is provided in the switching operation circuit of the expansion and operation valve in the driving hydraulic mechanism of the expansion arm. Extension arm safety device of a multi-stage telescopic working machine configured to stop the expansion operation by the expansion cylinder hydraulic cylinder by operating the shut-off valve by a signal input. A multistage telescopic working machine having a multistage telescopic arm that is telescopically stretched by a telescopic hydraulic cylinder, the telescopic sensing means capable of identifying the operation stage of the telescopic arm, and the expansion arm driving input of the detecting signal of the telescopic sensing means. In the multi-stage telescopic working machine provided with the multistage telescopic arm provided with a control unit, A relief valve capable of changing a set pressure in response to a command signal from the drive control unit is provided in the drive hydraulic mechanism of the axle arm, and the drive control unit receives a signal input from the expansion and contraction detection means in the setting operation step. And a command arm for changing the set pressure to be output to the relief valve. The multistage telescopic work machine according to any one of claims 1, 4, 5 or 6, comprising a multistage telescopic arm that is telescopically stretched by the telescopic hydraulic cylinder, wherein the telescopic arm can identify the operation stage of the telescopic arm. In the multi-stage telescopic working machine provided with a detection means and the multistage extension arm provided with the drive control part of an extension arm to which the detection signal of the expansion detection means is input, And a notifying means for notifying the arm operating step in response to the output signal from the drive control unit.