JP4043160B2 - Multistage telescopic work machine safety device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a working machine for a construction machine including a multistage telescopic arm, and more particularly, to a multistage telescopic working machine having a function of safely performing excavation work by a bucket attached to the tip of the multistage telescopic arm. It relates to safety devices.
[0002]
[Prior art]
Conventionally, in a hydraulic excavator having a multi-stage work arm that can be extended and retracted, a multi-stage telescopic work arm is extended by an extension means comprising a combination of a hydraulic cylinder and a wire rope to operate the work arm. Deep-drilling work is performed by a clamshell bucket attached to the tip. In doing this work, if the operator does not notice that the clamshell at the tip of the work arm is grounded, and if the work arm is extended or otherwise operated, it will result in inefficient useless work. Alternatively, the mounting support portion is overloaded and damaged.
[0003]
As a measure to prevent such inconvenience, for example, according to Utility Model Registration No. 2567611, a limit switch that operates when the clam shell attached to the lower end of the telescopic arm is grounded is provided, and at the time of arm holding operation performed by operating the remote control valve, The pressure switch connected to the pilot circuit is activated, and at the same time, the arm actuation relay is activated, the electromagnetic hydraulic switching valve is switched, the relief valve is activated, and the force applied to the arm cylinder provided at the boom tip is reduced. It has been described. Similarly, Japanese Patent No. 2728309 also describes a configuration in which the ground pressure of the clam shell is detected and the holding pressure of the arm cylinder is temporarily lowered. The limit switch for detecting the ground contact of the clamshell is operated by the displacement of the wire rope engaged in the expansion / contraction operation in association with the hydraulic cylinder that operates the expansion / contraction arm.
[0004]
[Problems to be solved by the invention]
In each of these prior arts, safety is maintained by means for reducing the lateral load on the work arm that expands and contracts by reducing the holding pressure in the arm cylinder attached to the tip of the boom. In general, this telescopic work arm has a structure that allows expansion and contraction operation by a hydraulic cylinder to be transmitted to each arm member of the expansion and contraction arm combined in multiple stages by a wire rope hung together. is there. Therefore, the wire rope is generally kept in tension.
[0005]
For this reason, there is a risk of a breakage accident when the wire rope is stretched by long-term use and the elongation of the wire rope is increased. Also, this kind of wire rope loses its balance and is damaged when an overload occurs on the telescopic arm as described above. Therefore, it is important to be able to perform maintenance and inspection sufficiently. However, in the prior art and other current situations, there is still a problem that it is not a satisfactory situation for grasping the state with respect to the elongation of the wire rope.
[0006]
The present invention has been made in view of such a situation, and detects a change in a wire rope for extending / contracting a multi-stage telescopic work arm to notify the landing of the tip of the work arm and a set value of the wire rope or more. The purpose of this is to make it easier to check the detector and to ensure safety.
[0007]
[Means for solving the problems and actions / effects]
  In order to achieve the above-described object, a safety device for a multistage telescopic work machine according to the present invention includes:
  The tension of the spring is applied to the end of the wire rope of the telescopic drive means in the telescopic arm of the multi-stage telescopic work machine.Deflection amountIs the default valueIt is abnormal to come offDetected by detection meansIsThenBy alarm meansAlert the operator in response to abnormal conditionsA safety device for a multistage telescopic work machine,
  The abnormality detection means includes a rod connected to one end portion of the extension side wire rope or the contraction side wire rope, and a spring whose deflection amount can be set by a spring adjustment means provided at the end of the rod. The non-contact sensor is arranged on the mounting support frame side of the wire rope end portion, and the holding member of the spring adjusting means that applies a mounting load to the spring by the non-contact sensor Configured to detect the amount of deflection of the spring.It is characterized by this.
[0008]
  In the present invention, when a load greater than the set value is applied to the telescopic arm during work, the spring that biases the tension force on the end portion of the wire rope of the telescopic drive means increases. If the amount of bending of the spring falls below the set value, the wire rope that is installed in tension will be loosened.AbnormalIt is possible to detect by the detecting means and notify the operator of the situation corresponding to each abnormality by an alarm so as to recognize the abnormality of the work, and it is possible to prevent danger in advance by corresponding to the abnormality. Therefore, when an excessive load is applied, for example, when the tip of the telescopic arm is landing, the operator is notified of the situation by an alarm, and the extension operation is immediately stopped and the next operation is started. Arouse. In addition, in the state where a warning that the wire rope is loose is issued, the operator is informed by the alarm that normal overload detection cannot be performed, and the work is stopped and the detection unit is urged to be reset. However, safety can be ensured by returning to normal.
[0009]
  In the present invention,A load that acts on the wire rope after the spring is bent by the spring adjustment means via the rod connected to the wire rope on the extension side or the contraction side, and the required tension is applied. The non-contact sensor arranged on the mounting support frame side detects that the holding member that contacts the spring moves from the set position along with the displacement of the spring as the rod connected by A state that deviates from the preset condition, in other words, that an abnormality has occurred in the operation of the telescopic arm is transmitted to the control electrical circuit with the detection signal, and the set device is operated to notify the operator of the abnormality. can do.
[0010]
  AbnormalitiesInspectionThe detecting means includes a non-contact sensor for detecting an excessive operation that detects that the spring is operated in a compressing direction by a load acting on the stretching side wire rope or the contracting side wire rope, and the spring is displaced to bend below a set value. Non-contact sensor for detecting looseness of wire ropeConsist ofIt is good. In this way, there is an advantage that each abnormality detection can be reliably detected by the corresponding sensor, and the abnormality can be transmitted by operating a predetermined device.
[0011]
  AbnormalitiesInspectionThe non-contact sensors of the knowledge means are preferably arranged at different positions with respect to the pressing member of the spring adjusting means for applying an attachment load to the spring, corresponding to different abnormality detections. This way, one wire ropeInAbnormalities under different conditions that act can be shared and detected, and can be treated reasonably. Also, the abnormalityInspectionKnowledge means are provided at the ends of the two stretched wire ropes installed in parallel,AbnormalOne of the detection meansButFor detecting overload abnormalitiesIsThe otherButIt is good for detecting the looseness of the wire rope. If it carries out like this, it can be set as the detection means with a sufficient installation, utilizing both wire rope terminal parts effectively.
[0012]
  Also, in the present inventionLeaveThe alarm means is the abnormalityInspectionA configuration in which a transistor and a relay are arranged in an electric circuit connected to an overload abnormality detection sensor in the knowledge means, and the relay is set to ON with a voltage being constantly applied to the overload abnormality detection sensor. It is good to be taken. In this way, in addition to safety measures that an alarm is issued when an overload abnormality is detected, an alarm is also issued for an abnormality such as an electric circuit disconnection, and it becomes possible to detect and respond to a circuit abnormality, etc. Countermeasures can be made more reliable. In the case of a circuit abnormality, even if it occurs during the work, the operator can be distinguished according to the work situation, and can be dealt with according to the situation.
[0013]
  Said alarm meansIs,Overload abnormalSensor for detectionOr sensor for detecting loosenessMultiple buzzers operated by a control electrical circuit linking withandWith lampRuIt is good. In this way, when an overload abnormality or a wire rope loosening abnormality is detected, it is possible to notify the operator of which abnormality has occurred by distinguishing between the buzzer sounding and the lamp lighting corresponding to the abnormality.
[0014]
In the present invention, a wire rope abnormality detection means is provided at the terminal portion of the contraction side wire rope, and a sensor of this detection means is connected to the alarm means so as to notify the operator of the contraction side wire rope abnormality. Is good. In this way, as in the case of the slack abnormality in the stretched wire rope, by adjusting the slack on the shrunk side, the influence of the stretch of the wire rope can be eliminated and safe driving can be performed.
[0015]
  Also,The alarm means that operates in response to a signal from a sensor of a detection means that detects an abnormality in the contraction-side wire rope is provided with a diode and a relay in an electric circuit connecting the detection sensor and the alarm buzzer, It is preferable that the abnormality alarm buzzer for the wire rope and the contraction side wire rope can be shared. In this way, it is possible to select a wire rope loosening abnormality by the function of the diode on the extending side and the contracting side, and to share the alarm buzzer to notify, and there is an advantage that the cost can be reduced by omitting the instrument. .
[0016]
  Further, a panel or alarm box in which the alarm lamps, buzzer, and alarm release switch in the alarm means are combined.ButIt is preferable to be disposed in front of the driver's seat. In this way, there is an advantage that identification of these abnormality occurrence parts becomes clear and the operator can easily deal with them.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, a specific embodiment of a safety device for a multistage telescopic work machine according to the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a perspective view of a construction machine provided with the multistage telescopic working machine of the present embodiment. FIG. 2 shows a schematic diagram of the telescopic drive mechanism in the telescopic arm of the multistage telescopic work machine, FIG. 3 is a plan view showing the arrangement of the safety device, and FIG. 4 shows the details of the safety device attached to the stretched wire rope. Each figure is shown.
[0019]
A multistage telescopic work machine 10 of this embodiment is configured such that a rear portion of a base arm 12 of an arm (hereinafter referred to as a telescopic arm 11) that expands and contracts at the tip of a boom 2 of a crawler traveling base machine 1 (in this example, a hydraulic excavator) is pinned. The rod end of the arm cylinder 3 that is connected and mounted on the upper part of the boom 2 is connected to the back of the upper end of the base arm 12 so that the boom 2 can be swung up and down at the tip of the boom 2. In addition, the clamshell bucket 15 is attached to the lower end, and is used for deep drilling work. The boom 2 is raised and lowered by the boom cylinder 4 and is operated in the cab 6 mounted on the upper swing body 5.
[0020]
As shown in FIG. 2, the telescopic arm 11 of the multistage telescopic work machine 10 is combined with the base arm 12 supported by the boom 2 of the base machine 1 and multistage in the base arm 12 to expand and contract. The top arm 13, the second arm 14, and an expansion / contraction drive mechanism 16 (corresponding to the expansion / contraction drive means of the present invention) incorporated therein. A hydraulic operation mechanism for operating a hydraulic cylinder 17 and a clamshell bucket 15 (see FIG. 1), which are drivers of the telescopic drive mechanism 16, is incorporated, and hydraulic piping is installed in these hydraulic devices from the base machine 1 side by well-known means. Has been. Each part of the telescopic arm 11 is slidably supported by known means. Note that the support structure and hydraulic piping of each part of the telescopic arm 11 are not directly targeted in the present embodiment, so illustration and description are omitted.
[0021]
The telescopic drive mechanism 16 includes a hydraulic cylinder (drive cylinder) 17 having a required operation stroke attached to a top arm 13 with a rear end and a front end supported and fixed, and an overall operation in conjunction with the expansion and contraction of the hydraulic cylinder 17. Is composed of an extension side wire rope 18 and a contraction side wire rope 19.
[0022]
The piston rod 17a of the hydraulic cylinder 17 is connected at the front end to the rear end portion of the second arm 14 (the expression of the rear end of the front end indicates the directionality when the telescopic arm 11 is raised). . The stretched-side wire rope 18 is supported at one end at a position A near the front end of the rear surface of the base arm 12, and the other end circulates through the sheave 21 attached to the rear end of the second arm 14. It is fixed at position B. Further, the contraction-side wire rope 19 is attached at one end to a support position C away from the end-portion support position A of the extension-side wire rope 18 near the tip of the rear surface of the base arm 12 and at the other end to the second arm 14. A sheave 22 attached to the front end of the top arm 13 is fixed around the sheave 22 and fixed to the rear end position D of the top arm 13. In this embodiment, two wire ropes 18 and 19 are wound around the stretch side and the contraction side.
[0023]
The telescopic drive mechanism 16 of the telescopic arm 11 configured as described above is provided with a safety device 30 for preventing an accident caused by the telescopic operation of the telescopic arm 11. The safety device 30 includes an overload abnormality detection means 31 for preventing the telescopic arm 11 from being overloaded, and the detection of the overload abnormality due to the occurrence of loosening of the wire rope. A wire rope looseness detection means 32 is provided for prevention.
[0024]
The safety device 30 is provided at the extension side wire rope end support position A of the base arm 12 and detects an overload abnormality at one of the attachment portions of the extension side wire ropes 18 and 18 that are installed around two windings. 31 and a looseness detecting means 32 are arranged on the other mounting part.
[0025]
The overload abnormality detection means 31 is a rod of a required length that is crimped by fitting the end portion of the stretched wire rope 18 (hereinafter simply referred to as the wire rope 18 unless otherwise noted) into the socket 33b and directly connected integrally. 33, a support structure 34 of the rod 33, a spring 36 for urging tension (attachment load) to the wire rope 18 via the rod 33, a spring adjusting means 37 for setting the attachment load on the spring 36, and The non-contact sensor 41 is included.
[0026]
The rod 33 is formed with a threaded portion 33a on the side opposite to the wire rope connecting side, and a supporting rib 34a (main body) having a required height provided perpendicularly to the outer surface on the back side of the base arm 12 as the supporting structure portion 34. The shaft support hole of the retainer 35 inserted through the base 35a from the front through the support hole 34c passing through the center of the boss 34b fixedly projecting on the rear side surface (rod insertion side) of the mounting support frame of the invention. The intermediate portion 35b is supported so as to be slidable in the axial direction. A screw 33a is engraved on the front half of the rod 33 so that the spring adjusting means 37 can be adjusted to move back and forth by the screw 33a. The spring adjusting means 37 is screwed into a presser piece 37a (corresponding to a presser member of the present invention) provided with a collar portion 37a 'having an appropriate thickness to be pressed against a front end surface of a spring 36, which will be described later, and a screw 33a portion of the rod 33. It consists of nuts 37b and 37b.
[0027]
A retainer 35 is supported between the holding piece 37a of the spring adjusting means 37 and the front side surface of the support rib 34a so that the rod 33 is slidably supported by the shaft support hole 35b and the base portion 35a is held by the boss 34b. A spring 36 is disposed via the. The spring 36 has a bending amount set so that the holding piece 37 a is moved by the nuts 37 b and 37 b of the spring adjusting means 37 to have a predetermined mounting load, and the mounting load is transferred from the spring adjusting means 37 through the rod 33 to the wire. It is added to the rope 18. The shaft support hole 35b of the retainer 35 is provided with a grease nipple 34d and an oil supply passage 34e so that grease is supplied from the outside of the boss 34b to facilitate sliding of the rod 33.
[0028]
At a side position of the arrangement portion of the rod 33 as described above, a base is orthogonal to the support rib 34a so as to be parallel to the axis of the rod 33 supported by the retainer 35 holding the base portion 35a to the boss 34b. A non-contact sensor 41 for detecting an overload abnormality is installed on a rib 38 fixed to the outer surface on the back side of the arm 12 in a direction crossing the axis of the rod 33 via a fixture 39. Then, the detection of the overload abnormality by the non-contact sensor 41 is performed so as to face the side surface of the collar portion 37a ′ of the pressing piece 37a of the spring adjusting means 37, as shown in FIG. The attachment position of the sensor 41 is set so that an abnormality is detected when the collar portion 37a 'of the presser piece 37a moves away from (represented by the symbol K in FIG. 4). The sensor mounting portion is preferably provided so that the position can be adjusted in the axial direction.
[0029]
With respect to the overload abnormality detection means 31 thus configured, the looseness detection means 32 has the same configuration as the overload abnormality detection means 31 in terms of its configuration. Therefore, the same structural parts in the looseness detection means 32 are denoted by the same reference numerals and detailed description thereof is omitted. As shown in FIG. 4, the attachment position of the sensor 42 is the attachment load setting position of the spring 36, and the pressing piece collar portion 37a 'of the spring adjusting means 37 is detected by the sensor 42 (reference numeral K' in FIG. 4). It is arranged so as to be located at a position away from a predetermined dimension. Further, it is preferable that the mounting portion of the sensor 42 is provided so that the position can be adjusted in the axial direction.
[0030]
Further, as shown in FIG. 3, the attachment end portion of the contraction side wire rope 19 is pivotally attached to the base arm 12 so that the ends of the two wire ropes 19 and 19 are fixed and balanced. A sensor 43 that detects non-contact looseness is provided at one side of the equalizer bar 45 to be supported by the bracket 46 at a side position of the equalizer bar 45, and the end of the equalizer bar 45 The sensor 43 detects the movement of the detection piece 45a attached to the sensor and generates a signal.
[0031]
  The sensor 41 of the overload abnormality detecting means 31 and the sensor 42 of the looseness detecting means 32 for the extension side wire ropes 18 and 18 and the sensor 43 for detecting the looseness of the contraction side wire ropes 19 and 19 are shown in FIG. As shown in the electrical diagram to operate,Base machineIt is electrically connected to an alarm notification section provided in one cab 6. In the circuit connecting each sensor 41, 42, 43 to the alarm lamps 51, 52, 53 and the alarm buzzers 54, 54 ', a transistor T₁, T₂, T₃, And relays R1, R2, and R3, and in the signal circuit of the sensor 43 for detecting the looseness of the contraction side wire rope, the alarm buzzer 54 'for detecting the extension is extended by interposing diodes D and D'. It can be shared with other things. In the figure, reference numeral 55 denotes a power source, and 56 denotes a changeover switch that can turn on / off the operation of the buzzer.
[0032]
As the alarm means 50, as described above, the alarm lamps 51, 52, and 53 that are turned on when an overload abnormality or loosening abnormality in the extension side wire rope 18 and a looseness abnormality in the contraction side wire rope 19 are detected, respectively, Alarm buzzers 54 and 54 'for notifying abnormality and loosening abnormality are provided. These alarm lamps 51, 52, 53 and alarm buzzers 54, 54 'are grouped in a monitor box 57 as shown in FIG. 6 by a front view (a) of the monitor using the lamp and a front view (b) of the buzzer box. Thus, it is arranged at a position where the driver can easily recognize the front part in the cab 6. These warning lamps are easily identified by, for example, setting the warning lamp 51 of an overload abnormality to yellow and the warning lamps 52 and 53 of each loosening abnormality (wire rope abnormality) to red. Further, the alarm buzzers 54 and 54 'are collected in a buzzer box 58 so that the buzzer sounds are different in accordance with the respective abnormalities so that they can be discriminated. The buzzer box 58 is provided with a changeover switch 56 for turning on / off the buzzer so that the buzzer sound can be stopped after the abnormality is confirmed.
[0033]
The operation of the safety device 30 configured as described above will be described.
First, the operation of the telescopic arm 11 will be described. When the telescopic drive mechanism 16 is instructed by the operator to extend in the cab 6, the pressure oil is sent to the bottom side of the hydraulic cylinder 17 and the piston rod 17a is actuated. . Then, the top arm 13 to which the hydraulic cylinder 17 is attached is moved forward in the second arm 14 based on the connecting portion E between the second arm 14 and the tip of the piston rod 17a. At this time, the stretched wire rope 18 provided with the safety device 30 and supported at the end by the base arm 12 is wound around a sheave 21 attached to the end of the second arm 14 in the middle. The wire rope 18 is pulled by the advance of the arm 13, the second arm 14 is advanced in the base arm 12 by the wire rope 18 according to the advance of the top arm 13, and the telescopic arm 11 is extended.
[0034]
Since the telescopic arm 11 is thus extended, for example, as shown in FIG. 1, when a deep digging operation is performed with the clamshell bucket 15 attached to the tip of the telescopic arm 11, the operator normally holds the telescopic arm 11 in the cab 6. When the clamshell bucket 15 reaches when it is extended, the extension operation is stopped by knowing the extension amount sensuously, and the next excavation operation is started. However, if the operator mistakenly or overlooks the landing and extends the telescopic arm 11 excessively, the clamshell bucket 15 at the tip is pressed more strongly after landing, and an excessive load acts on the telescopic arm 11. . If an excessive load acts on the telescopic arm 11 as a thrust in this way, an irregular external force acts on the distal end portion of the boom 2 or the arm cylinder 3 via the base arm 12, and the telescopic arm is damaged.
[0035]
However, in this embodiment, before such a situation occurs, if the tip of the telescopic arm 11 (clamshell bucket 15) lands and a force that extends beyond the pressing force required for excavation occurs, the top arm 13 The second arm 14 connected to the top arm 13 and the hydraulic cylinder 17 in a state where the oil pressure is applied to the bottom side is operated so as to be pushed back together with the top arm. Therefore, the stretch-side wire rope 18 is supported at the sheave 21 position at the end of the second arm 14 acting in the direction of being pushed up while maintaining the relative positional relationship with the top arm 13 and the base arm 12 to which the terminal portion is attached. Therefore, the rod 33 connected to the terminal portion is pulled in the backward direction (upward). Then, the safety device 30 supported on the base arm 12 is acted, and the warning means 50 is activated to notify the operator that a landing abnormality (overload abnormality) has occurred.
[0036]
Next, the operation of the safety device 30 will be described.
[0037]
When the tension applied to the wire rope 18 changes as described above, the rod 33 directly connected to the end of the wire rope 18 attached and supported to the base arm 12 by the support structure 34 is pulled in the direction of arrow P in FIG. Accordingly, the spring 36 biasing the mounting load via the spring adjusting means 37 is further compressed. When the presser piece collar portion 37a 'is moved outside the detection region (indicated by symbol K in FIG. 4) of the overload abnormality detection by the movement of the spring adjusting means 37, the sensor 41 generates a detection signal.
[0038]
When the overload abnormality detection sensor 41 generates a detection signal, the relay R1, R2, and R3 are all turned on in the operating state (a) with the power on in the electric circuit shown in FIG.₁As a result, the relay R1 is turned off, the alarm lamp 51 is lit, and the alarm buzzer 54 sounds (the state when an overload abnormality is detected in FIG. 7B). At this time, a yellow warning lamp 51 notifies the operator. The alarm buzzer 54 emits a sound such as “beep”. Therefore, if the operator stops the extension operation of the telescopic arm 11 by the alarm, it is possible to prevent an excessive load from acting on the telescopic arm 11 and to avoid damage.
[0039]
Further, when the wire rope is extended due to long-term or frequent operation and the wire rope 18 is loosened more than a certain level, the mounting load acting on the rod 33 connected to the terminal portion becomes less than the initial set value and the spring. The amount of bending of 36 is reduced, and the rod 33 is returned. Then, the spring adjusting means 37 in contact with the end of the spring 36 in the safety device 30 is pushed back, and the flange portion 37a 'of the pressing piece 37a is detected by the detection region 42 of the sensor 42 for detecting the looseness (indicated by symbol K' in FIG. 4). The sensor 42 emits a detection signal.
[0040]
When the wire rope looseness detection sensor 42 generates a detection signal, the relays R1, R2, and R3 are all on in the operating state (a) with the power on in the electrical circuit shown in FIG. Similar to the detection of the load abnormality, the transistor T₂As a result, the relay R2 is turned off, the alarm lamp 52 is lit, and the alarm buzzer 54 'sounds. The operator is notified by the red warning lamp 52 at this time. The alarm buzzer 54 'emits a continuous sound such as "Pee". Therefore, the operator knows that the wire rope is excessively loosened by the alarm.
[0041]
If the work is continued in such a state, even if the above-mentioned overload abnormality has occurred, the predetermined load is not urged on the wire rope, so the overload abnormality cannot be detected normally. Risk of accidents. Therefore, if an alarm for the occurrence of looseness is received, operation can be stopped and the nuts 37b and 37b of the spring adjusting means 37 in the safety device 30 can be operated in the tightening direction to reset them to the initial set values, thereby enabling safe work. is there.
[0042]
In addition, even when the circuit a (sensor 41 circuit or relay R1 circuit) that detects the overload abnormality and issues an alarm is disconnected, it is the same as in the overload abnormality. In this case, whether the alarm is due to an overload abnormality or the disconnection can be distinguished from the work situation. That is, it can be distinguished depending on whether the alarm is for a specific work (landing during excavation work) or an alarm other than that.
[0043]
  Next, the action of the spring 36 in the safety device will be described. As shown in the load diagram of the spring in FIG. 8, the spring 36 is set by the spring adjusting means 37 with its set load determined in advance at the initial setting. Load (mounting load) is F₀Bend until set. Then, it exceeds the mounting load at the time of setting and is further compressed (the amount of bending increases) and bends to F1 (Wire ropeThe sensor 41 detects that the spring compressive load is applied to the alarm means 50 and activates the alarm means 50.
[0044]
  In addition, a pre-tension F is applied to the wire rope 18 by the spring 36.₀Therefore, even when the wire rope 18 extends 10 mm,Wire ropeF₀Since the tension of / 2 remains, there is no such thing that the wire rope 18 dances (a phenomenon that swings to the left and right). (conventionally,Wire ropeWhen extending 1-2mmWire ropeThe tension applied to theWire ropeSo often danceWire ropeIt was necessary to adjust the tightening. Therefore, according to the present embodiment, the tension of the wire rope is adjusted so that the spring force by the spring 36 is F as described above.₀When the tension reaches / 2, the wire rope stretch (loosening) is detected, and the tension is adjusted so that the spring force F₀If it is reset again, the spring force F will always be₀Can be secured, and it is safe to prevent damage caused by the dance of the wire rope. F represented by the load diagram₂Since the spring is damaged until it is compressed (bends), a stopper is provided to prevent the spring from being excessively bent although not shown.
[0045]
The safety device related to the extension side wire rope 18 has been described above, but the contraction side wire rope 19 is stretched by connecting the end portions of the two wire ropes to the equalizer bar 45 that attaches to the base arm 12. The looseness can be detected by the non-contact sensor 43 for detecting the looseness at a position facing the detection piece 45a attached to the movable end of the equalizer bar 45.
[0046]
In this way, when the tension balance between the two contraction-side wire ropes 19, 19 is lost, the end position of the equalizer bar 45 shifts back and forth from the normal position, and the displacement due to the shift is detected by the sensor 43 to give an alarm. The means 50 can be activated to notify the operator of the abnormality. The abnormality detection by the sensor 43 is connected to the alarm means 50 as shown by the above-described electric circuit (see FIG. 5), and the transistor T is detected in the same manner as when the looseness in the extension side wire rope 18 is detected.₃, The relay R3 is turned off and the alarm lamp 52 and the alarm buzzer 54 'are activated and extended by the operation of the diodes D and D' provided in the circuit connecting the sensor 43 and the alarm means 50. A warning similar to the looseness warning of the side wire rope 18 can be issued.
[0047]
When the telescopic arm 11 contracts, when the supply of pressure oil is switched to the piston rod 17a side of the hydraulic cylinder 17 and the piston rod 17a is retracted, the top arm 13 to which the hydraulic cylinder 17 is attached becomes the piston. It is moved to the rear end side of the second arm 14 connected to the tip end of the rod 17a. At this time, the contraction-side wire rope 19 supported at one end by the base arm 12 and connected at the other end to the rear end of the top arm 13 attaches the second arm 14 via a sheave 22 attached to the tip of the second arm 14. The retractable arm 11 is retracted positively, the telescopic arm 11 is contracted, and the clamshell bucket 15 at the tip of the top arm 13 is pulled up. Thereafter, the boom 2 is raised and the arm cylinder 3 is operated to change the posture of the telescopic arm 11 in order to discharge the earth and sand excavated by lifting the clamshell bucket 15 to the ground.
[0048]
Next, FIG. 9 shows another embodiment of the safety device. The safety device 30A in this embodiment is a case where one stretch-side wire rope is used in the telescopic drive mechanism of the telescopic arm, and its configuration is basically the same as that in the above-described embodiment. Accordingly, the same or similar parts as those in the above embodiment are designated by the same reference numerals and detailed description thereof is omitted.
[0049]
  In this safety device 30, a rod 33 directly connected to the end of the wire rope 18 </ b> A is used as a retainer for fitting and supporting a base portion 35 a in a support hole 34 c of a boss 34 of a support structure portion 34 provided on a base arm or another movable arm. A screw provided in the front half of the rod 33, which is slidably inserted into the shaft hole 35b of the 35 and supported.33aA spring 36 is interposed between the spring adjusting means 37 attached to the portion and the front surface of the flange 35c of the retainer 35 supported by the support structure 34, and the spring 36 is attached to the rod 33 via the spring adjusting means 37. A mounting load is applied. Then, overload abnormality detection is performed so as to face the flange portion 37a 'of the pressing piece 37a of the spring adjusting means 37 and to be located in the detection region K at the mounting load setting position of the spring 36 by the spring adjusting means 37. The sensor 41 for detecting the looseness of the wire rope is disposed at a position away from the position by the required dimension S, and the tension acting on the wire rope 18A increases as described above, so that the detection region K of the sensor 41 is increased. An overload abnormality is detected when the collar portion 37a 'of the presser piece 37a is removed from the arm. Further, when the flange portion 37a 'of the presser piece 37a moves to the detection region K' of the sensor 42, the looseness of the wire rope is detected. Since the operation for alarming the operator by detecting each abnormality is the same as that in the above embodiment, a description thereof will be omitted.
[0050]
  Thus, in this embodiment, oneWire ropeTherefore, the operator can warn the operator of overload abnormalities and loosening of the wire rope.
[0051]
FIG. 10 further shows another embodiment of the safety device. The safety device 30B in this embodiment is another embodiment in which one stretch-side wire rope is used in the telescopic drive mechanism of the telescopic arm, and its configuration is basically the same as that of the above-described embodiment. Accordingly, the same or similar parts as those in the above embodiment are designated by the same reference numerals and detailed description thereof is omitted.
[0052]
This safety device 30B is a retainer in which a rod 33 that is directly connected to the end of a wire rope 18A by a socket 33a is held by fitting a base 35a to a boss 34b by a support structure 34 of a base arm or a movable arm. The rod 33 is inserted into the shaft hole 35b and supported so as to be slidable back and forth. A screw 33b is formed on the front half of the rod 33, and is attached to the screw 33b via nuts 37b and 37b. The provision of the spring adjusting means 37 is the same as in the above embodiment.
[0053]
The difference in the configuration of the safety device 30B is that the retainer 35A is integrally provided with a cylindrical case 38 in which the spring 36 can be housed, and the pressing piece 37c of the spring adjusting means 37 is provided on the spring case 38. It is formed into a shape that fits into the opening, and has a structure that surrounds the portion where the spring 36 and the amount of deflection thereof are set. By adopting such a structure, generation of rust and biting of foreign matter at the adjustment main part are not generated, and reliability can be improved.
[0054]
As shown in the figure, the safety device 30B includes detection means including an overload abnormality detection sensor 41 and a wire rope slack detection sensor 42 on both sides of the rod 33, and the spring adjustment means 37. Are provided so as to be opposed to each other so as to be detected in the manner described above by the movement of the peripheral edge portion 37c 'of the pressing piece 37c.
[0055]
By attaching the safety device of the present embodiment to the multistage telescopic work machine, in the case of the work machine provided with the clamshell bucket 15 at the tip of the telescopic arm 11 described above, the deep work was excavated. Loading the earth and sand directly onto the dump truck enables the loading operation to be carried out effectively without performing a safer and wasteful operation than in the past.
[0056]
That is, as shown in FIG. 11, which shows a bucket discharging mode in a multistage telescopic working machine, after the telescopic arm 11 is pulled up and contracted, the boom 2 is raised in the base machine 1 and the arm cylinder 3 The clam shell bucket 15 at the tip of the telescopic arm 11 is pulled up from the opening hole of the excavation part to the ground part and moved onto the loading platform of the dump truck 60 that is waiting to be discharged (loaded).
[0057]
When dumping excavated soil such as this, if the inclination angle β with respect to the horizontal line of the telescopic arm 11 falls below a set value, the discharge height of the excavated soil of the load increases, and the loading shock of the dump truck 60 increases. There are problems such as shortening the life of the dump truck 60 and increasing the effect of shock on the driver of the dump truck 60. In addition, the load is increased more than necessary, and the efficiency in loading work is deteriorated.
[0058]
When the inclination angle β of the telescopic arm 11 during dump loading of the excavated soil is below a certain angle, the stretching load increases due to the frictional resistance when the telescopic arm 11 is expanded and contracted, and the load on the stretching side wire rope 18 is large. It becomes. Therefore, when the safety device 30 (30A, 30B) of the present embodiment is provided, the spring 36 associated with the end of the wire rope 18 (18A) increases the amount of deflection, and the non-contact sensor (41) increases the excess amount. Since the load is detected and the operator is notified of an abnormality (overload) by the alarm lamp 51 or the alarm buzzer 54 of the alarm means 50, the operator can prevent such wasteful and unsafe work. . In short, it is possible to improve workability during dump loading work.
[0059]
In the above description, the load on landing and the stretching load on loading may be set with the same load or set to different loads in order to represent a single sensor for overload detection of the stretching side wire rope. May be. However, when setting a different load, another load detection sensor may be added.
[0060]
  The safety device attached to the telescopic arm mentioned above isWire ropeAlthough the embodiment provided in the end support portion has been described, the same configuration can be provided in the support portion at the contraction side wire rope end as required. In the above-described embodiment, an example is described in which the base arm is provided on the base arm in a stationary state when extending and contracting. However, in some cases, the base arm may be provided on a portion that becomes a movable part arm such as a second arm. However, in this case, it can be implemented by changing a part of the wire rope winding means. The working machine may be a telescopic arm used for other work as well as deep work.
[Brief description of the drawings]
FIG. 1 is a perspective view of a construction machine provided with a multistage telescopic working machine according to the present embodiment.
FIG. 2 is a schematic diagram of an extension drive mechanism in an extension arm of a multistage extension work machine.
FIG. 3 is a plan view showing the arrangement of the safety device.
FIG. 4 is a detailed view of the safety device attached to the stretcher-side wire rope.
FIG. 5 is an operational electric circuit diagram of an alarm means.
FIG. 6 is a front view of a lamp monitor (a) and a front view of a buzzer box (b).
FIGS. 7A and 7B are diagrams showing an operation mode in the operating electric circuit of the alarm means, in which FIG. 7A shows an operation state when the power is turned on, and FIG. Yes.
FIG. 8 is a load diagram of a spring.
FIG. 9 is another embodiment of the safety device.
FIG. 10 is another embodiment of the safety device.
FIG. 11 is a diagram illustrating a bucket discharging mode in a multistage telescopic working machine.
[Explanation of symbols]
1 Base machine
2 Boom
3 Arm cylinder
6 cab
10 Multi-stage telescopic work machine
11 Telescopic arm
12 Base arm
13 Top arm
14 Second arm
15 clamshell bucket
16 Extension drive mechanism (Extension drive means)
17 Hydraulic cylinder
17a Piston rod
18, 18A Stretch side wire rope
19 Shrinking wire rope
21, 22 Sieve
30, 30A, 30B Safety device
31 Overload abnormality detection means
32 Wire rope slack detection means
33 Rod
34 Support structure
34a Support rib
34b boss
35 Retainer
36 Spring
37 Spring adjustment means
37a Presser piece
38 cases
41 Sensor for overload abnormality detection
42 Sensor for detecting looseness of wire rope
43 Sensor for detecting abnormalities at the end of the wire rope
45 Equalizer bar
50 Alarm means
51, 52, 53 Alarm lamp
54, 54 'Alarm buzzer
60 dump truck
T₁, T₂, T₃        Transistor
R1, R2, R3 relay
D, D 'diode

Claims (9)

Urges the tensioning force of the spring to the terminal portion of the wire rope of the telescopic driving means in the telescopic arm of the multi-stage telescopic working machine, when the deflection amount of the spring is out of the default values Ru is detected by the abnormality detection means , A safety device for a multi-stage telescopic work machine that issues an alarm corresponding to an abnormal situation to an operator by an alarm means ,
The abnormality detection means includes a rod connected to one end portion of the extension side wire rope or the contraction side wire rope, and a spring whose deflection amount can be set by a spring adjustment means provided at the end of the rod. The non-contact sensor is arranged on the mounting support frame side of the wire rope end portion, and the holding member of the spring adjusting means that applies a mounting load to the spring by the non-contact sensor A safety device for a multistage telescopic work machine, wherein the safety device is configured to detect the amount of bending of the spring . The abnormality detection known means includes a non-contact sensor of excessive operation detection for detecting that operates in a direction to compress the spring load acting on the stretched side wire rope or the compression-side wire rope, spring following settings The safety device for a multistage telescopic work machine according to claim 1 , further comprising a non-contact sensor for detecting looseness of the wire rope that detects the displacement due to bending. Non-contact sensors of the abnormality detection known means, corresponds to a different abnormality detected, relative to the pressing member of the spring adjusting means for applying a mounting load in the spring, according to claim 2 disposed in different positions Safety device for multistage telescopic work machines. The abnormality detection known means, respectively provided in the terminal portion of the two of stretched side wire ropes which are laid in parallel, one of which abnormality detecting means is a for detecting the abnormal overload, loosening the other of the wire rope The safety device for a multistage telescopic work machine according to claim 3 , which is used for detection. It said alarm means, wherein in the electric circuit connecting the detection sensors abnormal overload by the abnormality detection known means, by arranging the transistors and relays, the state obtained by adding a constant voltage to the sensor for detecting the abnormal overload The safety device for a multistage telescopic work machine according to claim 4 , wherein the relay is configured to be turned on. It said alarm means, the safety device of the multi-stage telescopic working machine according to claim 5, Ru comprising a plurality of buzzer and lamp operated by abnormal overload of the detection sensor or control circuitry connecting the slack detection sensor. Detection means compression-side wire rope end portion of the wire rope abnormality provided, according to the abnormality of the detection means compression-side wire rope connected to the alarm means of the sensor in claim 1, so as to inform the operator Safety device for multistage telescopic work machines. The alarm means that operates in response to a signal from a sensor of a detection means that detects an abnormality in the contraction-side wire rope is provided with a diode and a relay in an electric circuit connecting the detection sensor and the alarm buzzer, The safety device for a multistage telescopic work machine according to claim 7 , wherein the abnormality alarm buzzer of the wire rope and the contraction side wire rope can be shared. 2. The safety device for a multistage telescopic work machine according to claim 1, wherein a panel or alarm box in which the alarm lamps, buzzer, and alarm release switch in the alarm means are gathered is disposed in front of the driver's seat.

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