JP4173421B2 - Lifting device for construction machinery - Google Patents

Description

  The present invention relates to a lifting device suitable for use in a large construction machine or the like.

  As an elevating device used for a large construction machine, it is known to attach a sliding or folding ladder to the construction machine body (see Patent Documents 1 and 2).

JP 2001-173019 A Japanese Patent Laid-Open No. 2000-255459

  The elevating device described in Patent Document 1 is provided with a guide portion inclined to the construction machine main body frame, and is supported by the guide portion so as to be slidable in the vertical direction. And a ladder that moves up and down between positions. This lifting device has a problem that the ladder has a steep slope due to the limitation of the installation space, it is necessary to carefully lift and lower, and it is difficult to lift and lower while holding baggage. Further, when the construction machine main body is increased in size, a long slide distance is required, and the guide portion has to be made very long, resulting in a problem that more installation space is required.

  The lifting device described in Patent Document 2 includes a first split ladder attached to a construction machine main body so as to be rotatable in a vertical direction from a standing posture to a suspended posture, and a vertical direction at a free end of the first split ladder. And a stopper that functions as a column between the second divided ladder and the lower traveling body is attached to the second divided ladder. In use, the first and second divided ladders are manually suspended in a straight line, and a stopper is interposed between the innermost lower end of the second divided ladder and the traveling body under the construction machine. At the time of storage, the first and second divided ladders are folded while being manually rotated upward to be in a standing posture. At this time, the first divided ladder is urged in a direction to hold the standing posture by the pneumatic cylinder. In order to gently maintain the gradient of the ladder when the ladder is deployed, the stopper may be lengthened. However, when the stopper is lengthened, there is a problem that the stopper interferes with the operation when the ladder is deployed. In addition, when the construction machine main body becomes larger, the ladder becomes larger, and raising and lowering the ladder is difficult.

(1) A lifting device for a construction machine according to a first aspect of the present invention includes a first ladder portion provided on a revolving body of the construction machine so as to be pivotable in a vertical direction, and a vertical direction at a tip of the first ladder portion. A second ladder unit that is rotatably connected, an actuator that rotates the first ladder unit, and a second ladder that is linked to the movement of the first ladder unit that is driven by the actuator to the retracted state. And a link mechanism for driving the part to fold to the first ladder part.
(2) The lifting device for a construction machine according to the invention of claim 2 is characterized in that, in the lifting device of claim 1, a mechanism is provided for maintaining the inclination angle of the ladder portion in the lift device use state by the actuator and the link mechanism. To do.
(3) The lifting device for a construction machine according to the invention of claim 3 is the lifting device according to any one of claims 1 and 2, wherein the actuator is a hydraulic cylinder, and the hydraulic circuit for driving the hydraulic cylinder includes a hydraulic pump and A main circuit composed of a first switching valve that determines the expansion and contraction operation of the hydraulic cylinder, and a second switching valve that determines whether or not the hydraulic pressure of the pump for driving the construction machine is supplied to the hydraulic cylinder, The second switching valve is switched so that pressure oil necessary for maintaining the stored state is supplied to the hydraulic cylinder at least in the stored state.
(4) The lifting device for a construction machine according to the invention of claim 4 further includes means for detecting that the lifting device is in use or retracted in the lifting device according to claim 3, and the detection means is used. When a state other than the state is detected, the second switching valve is switched, pressure oil is supplied from the construction machine drive pump to the hydraulic cylinder, and when the detecting means detects the retracted state, the turning operation of the turning body is disabled. It is characterized by that.
(5) The lifting device for a construction machine according to the invention of claim 5 is the lifting device according to claim 3, wherein the gate lock lever switch and the operation switch of the lifting device are interlocked to make the swinging body impossible to swing. The lifting device can be shifted from the retracted state to the in-use state only when unlocked.

(1) According to claim 1, by making the ladder part a folding type, the gradient of the ladder can be moderated and the raising and lowering can be facilitated without increasing the installation space much compared to the sliding type as in Patent Document 1. At the same time, it is possible to move up and down while holding baggage. Further, the actuator and the link mechanism eliminate the need to manually raise and lower the ladder as in Patent Document 2.
(2) According to claim 2, the inclination angle of the retractable ladder in use can be maintained by the actuator and the link mechanism. As a result, the stopper required in Patent Document 2 becomes unnecessary, and the problem that the stopper hinders the operation at the time of ladder deployment can be solved.
(3) According to Claims 3 and 4, since the pressure oil of the pump for driving the construction machine is supplied to the hydraulic cylinder in the retracted state to hold the ladder in the retracted state, the vehicle body vibration generated when the vehicle body is in operation It is possible to reliably prevent the rattling of the ladder that accompanies. In addition, by providing detection means for detecting the attitude of the lifting device, the pressure rises from the construction machine drive pump even when the engine is started, so that the ladder rises freely. Can be prevented. Since the revolving operation of the revolving structure is disabled when it is not in the retracted state, it is possible to avoid an accident in which the revolving device is accidentally swiveled and the lifting device is damaged.
(4) According to claim 5, since the ladder can be shifted from the retracted state to the in-use state only when the gate lock is released, the operation switch can be actuated during the vehicle body driving operation to lower the lifting device. It is not possible to avoid an accident that the lifting device is damaged.

――― First embodiment ―――
FIGS. 1-8 is one Embodiment of the raising / lowering apparatus in this invention, FIG.1, 2 is a side view which shows the main-body part of the hydraulic shovel which is an example of the construction machine to which this invention is applied, respectively with the ladder lowered. , Top view, FIGS. 3, 4, and 5 are respectively a state in which the ladder is lowered (in use), a side view of the ladder and a mounting portion thereof in the state of being raised and lowered (in a retracted state), and FIG. 6 is a state in which the ladder is used. FIG. 7 is a detailed view of a lock mechanism used in the ladder retracted state, and FIG. 8 is a hydraulic / electric circuit diagram for driving a hydraulic cylinder which is a power source for raising and lowering the ladder.

  1 and 2, the hydraulic excavator is configured such that a revolving body 30 is installed on a traveling body 33 via a revolving device 34, and a cab 31 is installed on the revolving body 30. The lifting / lowering device 1 is for an operator or a worker to move up and down between the revolving structure 30 and the ground. The lifting / lowering device 1 is attached to the front side of the side walk 32 provided for walking on the side surface of the revolving structure 30 (on the side of the cab 31 in the revolving structure 30).

  The ladder which comprises the raising / lowering apparatus 1 has the 1st division | segmentation ladder 2 and the 2nd division | segmentation ladder 3, as shown in FIG. The first divided ladder 2 is attached to the side walk 32 via the first joint portion 2a, which is a connecting portion using pins, so as to be rotatable in the vertical direction from the standing posture to the obliquely downward posture. The second split ladder 3 is attached to the second joint portion 2b on the free end side of the first split ladder 2 so as to be rotatable in the vertical direction. Handrails 2c and 3a and steps 2d and 3b are attached to the divided ladders 2 and 3, respectively.

A hydraulic cylinder 4 is mounted between the side walk 32 and the first split ladder 2 to drive the lifting device 1 up and down via connecting portions 4c and 4d using pins.
A rod 5 is attached between the side walk 32 and the second divided ladder 3 via a link 6 and a link 7. The link 6 has a triangular shape, and the three vertices of the link 6 are connected to the first divided ladder 2, the vertex 6b is connected to the rod 5, and the vertex 6c is connected to the link 7 by a pin. The other end 7a of the link 7 is connected to the second divided ladder 3 by a pin.

  As shown in FIG. 7, each of the first divided ladder 2 and the second divided ladder 3 is pressed and held against the first divided ladder 2 in a posture in which the ladder is raised. A stopper receiver 8 and a stopper 9 are attached. The stopper 9 includes a lock 9b, a lever 9a for rotating the lock 9b around a fulcrum 9c, a spring 9d for fixing the position of the lever 9a, a bracket 9e for attaching the spring, and a switch member 9f for operating a limit switch. The stopper receiver 8 includes a pin 8a that the lock 9b catches when the ladder is stored. These constitute the lock mechanism 100.

  Limit switches 10 and 11 for detecting that the ladders 2 and 3 are in use or retracted are attached in the vicinity of the connecting portion 4d and the stopper receiver 8 of the hydraulic cylinder, respectively.

  In this configuration, as shown in FIG. 3, when the ladder is in use, the hydraulic cylinder 4 has the maximum contraction length, and the angle of the first divided ladder 2 is kept constant. Since the second divided ladder 3 is prevented from rotating downward by the rod 5 via the link 6 and the link 7, the second divided ladder 3 does not contact the traveling body 33 or the ground, and the first divided ladder 3 The ladder 2 and the rotation plane are kept in a straight line.

  In the state of FIG. 3, the worker or the operator ascends and gets on the lifting device 1 from the ground to the turning body 30. When the ride on the side walk 32 is completed, the operation switch 12 attached to the swing body 30 in the vicinity of the lifting device 1 is pushed to drive the hydraulic cylinder 4 in the extending direction. When the hydraulic cylinder 4 extends, the first split ladder 2 starts to rotate clockwise around the connecting portion 2a. The first divided ladder 2, the link 6, the rod 5, and the side walk 32 form a four-joint link having four connecting portions 2 a, 6 a, 6 b, and 5 a. Starts to rotate upward, the link 6 starts to rotate counterclockwise with respect to the first divided ladder 2 around the connecting portion 6a. Accordingly, the second divided ladder 3 starts to rotate counterclockwise via the link 7 attached to the one end 6c of the link 6. FIG. 4 shows a state in which the lifting device 1 goes up. As the first divided ladder 2 rises, the second divided ladder 3 is folded in conjunction.

In the posture (storage posture) in which the lifting / lowering device 1 shown in FIG. 5 is fully raised, the second division ladder 3 is pressed against the first division ladder 2 by the lock mechanism 100 shown in detail in FIG. To do. When the ladder is lowered, that is, when the ladder is used, the stopper 9 is set at the position 9B, the ladders 2 and 3 are folded, and when the pin 8a of the stopper 8 and the lock 9b come into contact with each other, the lock 9b becomes the pin 8a. When the ladder is moved counterclockwise and moved to the retracted position, the lock 9b and the pin 8a are engaged with each other as shown in FIG. When lowering the ladder, the lever 9a is rotated to the position 9A, and the lock 9b is removed from the pin 8a. The lever 9a is held at the 9A position by the tensile force of the spring 9d. Thereafter, the operation switch 12 is pressed to lower the ladder.

  FIG. 8 shows an electric / hydraulic circuit for driving the hydraulic cylinder 4. B indicates a power source. Each contact of the operation switch 12 is normally open. When the operation switch 12 is pressed, each contact is closed. In the limit switch 10, when the ladders 2 and 3 are in use, the contact 10a and the contact 10b are opened, and the contact 10c and the contact 10d are opened. When the ladders 2 and 3 are not in use, the contact 10a and the contact 10b are closed, and the contact 10c and the contact 10d are closed. In the limit switch 11, when the ladders 2 and 3 are in the retracted state, the contact 11a and the contact 11b are opened, and the contact 11c and the contact 11d are closed. When the ladders 2 and 3 are not in the retracted state, the contact 11a and the contact 11b are closed, and the contact 11c and the contact 11d are opened.

  Although not shown, the relay of the electric motor 14 is closed by the operation of the operation switch 12 and the electric motor 14 is activated to drive the pump 15. The electric motor 14 operates only when the operator operates the operation switch 12. When the hydraulic cylinder 4 is extended (the lift device 1 in use is in the retracted state), a switching signal is given to the solenoid 16b side of the three-position switching valve 16, and the three-position switching valve 16 is switched to the A position. The hydraulic pressure is supplied to the bottom side 4a. When the hydraulic cylinder 4 is contracted (the lifting device 1 in the retracted state is used), a switching signal is given to the solenoid 16a side of the three-position switching valve 16, and the three-position switching valve 16 is switched to the low position. The hydraulic pressure is supplied to the rod side 4 b of 4. The neutral position of the three-position switching valve 16 is a circuit in which the hydraulic cylinder rod side 4b communicates with the tank 28 and the bottom side 4a is shut off. As a result, when the lifting / lowering device 1 in the retracted state is lowered to the use state, even if the second divided ladder 3 comes into contact with an obstacle such as a stone, when the operator releases the operation switch 12, the position is switched to three positions. The valve 16 returns to neutral, the rod side 4b communicates with the tank 28, and the pressure is released, so the second split ladder 3 does not remain pressed against the obstacle. Thereby, breakage of each part of the lifting device 1 is prevented. Further, it is not necessary to provide an overload relief valve on the hydraulic cylinder rod side 4b, and the cost can be reduced.

  Pressure oil is supplied to the bottom chamber side 4a of the hydraulic cylinder 4 from the pump 20 of the radiator fan circuit of the swing body 30 except when the ladder is in use. This prevents the rudder from rattling due to the vibration of the vehicle body when the vehicle body is operating. An electromagnetic valve 21 is interposed between the pump 20 and the bottom side 4 a of the hydraulic cylinder 4. As described above, when the ladder is in use, the contacts 10a and 10b of the limit switch 10 are opened, so that the solenoid of the solenoid valve 21 is demagnetized and the pressure oil is shut off. When the ladder is not in use, the contacts 10a and 10b of the limit switch 10 are closed, so that the solenoid of the solenoid valve 21 is excited and pressure oil is supplied to the bottom chamber. This prevents the lifting device 1 from being lifted even though the operation switch 12 is not operated when the engine is started. Whether the ladder is completely lowered or raised is detected by limit switches 10 and 11 and switch members 10a and 9f shown in FIGS. When the raising or lowering of the ladder is not completed, the contacts 10c and 10d of the limit switch 10 are closed, and the contacts 11a and 11b of the limit switch 11 are closed. Thus, when the raising or lowering of the ladder is not completed, the alarm buzzer 13 continues to sound, so that the operator can easily confirm whether the raising or lowering is completed while operating the operation switch 12. Note that the alarm buzzer 13 continues to sound while the operation switch 12 is being operated.

  A stop valve 23 is provided between the pump 20 and the hydraulic cylinder 4. The hydraulic cylinder 4 can be extended by opening the stop valve 23 and guiding the pressure oil to the hydraulic cylinder bottom chamber when an electrical system failure occurs. As a result, the ladder can be shifted to the retracted position even in the event of an electric system failure, and a series of operations such as excavation, turning, and traveling can be performed.

  A gate lock lever switch 40 is provided between the power source B and the solenoids 16 a and 16 b of the three-position switching valve 16. The gate lock lever switch 40 is opened and closed by operating a gate lock lever 31a provided in the cab 31. When the gate lock lever 31a is operated to the gate lock position, the gate lock lever switch 40 is opened. When the gate lock lever 31a is operated to the gate lock release position, the gate lock lever switch 40 is closed. Thereby, when the gate lock lever 31a is operated to the gate lock position, even if the operation button 12 is operated, the solenoids 16a and 16b are not excited, and the pressure oil of the pump 15 is not supplied to the hydraulic cylinder 4. When the gate lock lever 31 a is operated to the gate lock release position, the solenoid 16 a or the solenoid 16 b is excited by the operation of the operation button 12, and the pressure oil of the pump 15 is supplied to the hydraulic cylinder 4. Therefore, by interlocking the gate lock lever switch 40 and the operation switch 12, it is possible to shift the lifting device 1 from the retracted state to the used state only when the gate lock is released (the turning body cannot be turned). The gate lock lever 31a is provided at the entrance / exit of the cab 31 and is operated between the gate lock position and the gate lock release position. When the gate lock lever 31a is in the gate lock release position, the hydraulic actuator or the like that drives the turning device 34 is not driven even if the operation lever is operated.

The lifting device of the first embodiment described above has the following operational effects.
(1) Since the steps are gentle, it is easy to move up and down from the ground to the revolving structure, and it is possible to get on with the baggage.
(2) Due to the mechanical lock mechanism and hydraulic circuit configuration, it is possible to prevent the rattling vibration of the ladder during deployment and storage.
(3) By linking the limit switch, the gate lock lever switch, and the operation switch, it is possible to prevent an accident in which the lifting device hits the traveling body and is damaged.

――― Second embodiment ―――
With reference to FIG. 9, a second embodiment of the lifting apparatus according to the present invention will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be mainly described. In the present invention, the folding type lifting device 1 composed of the divided ladders 2 and 3 is attached, but a lifting device 1B as shown in FIG. 10 may be used. The lifting device 1B includes a slide ladder 38. The slide ladder 38 is configured to slide a guide portion provided with a guide portion provided in the divided ladder 3. The slide ladder 38 is stored so as to overlap with the divided ladder 3 in the stored state, and slides a guide portion provided on the divided ladder 3 in the used state, and is positioned below the divided ladder 3.

In the lifting device according to the second embodiment described above, the following operational effects are obtained in addition to the operational effects of the first embodiment.
(1) When the construction machine main body becomes larger and the distance from the ground of the revolving structure 30 or the side walk 32 to which the lifting / lowering device 1B is mounted becomes longer, the installation space during storage is greatly expanded by attaching the slide ladder 38. The lifting device can be lengthened.

――― Modifications ――――
(1) In the above description, a hydraulic cylinder is used as a driving force for rotating the first divided ladder 2, but the present invention is not limited to this, and other power sources such as a winch may be used. .
(2) Further, except when the elevating device 1 is in use, the pressure oil from the radiator fan circuit is supplied to the hydraulic cylinder bottom side 4a. A source may be used.
(3) Furthermore, in the embodiment, the stop valve 23 is provided only between the pump 20 of the radiator fan circuit and the hydraulic cylinder bottom chamber 4a. However, by providing a stop valve between the pump 20 and the rod side 4b as well. The elevator device 1 may be shifted from the retracted state to the in-use state when an electrical system failure occurs.
(4) Furthermore, the lifting device 1 can be raised and lowered only when the operation switch 12 is operated. However, the operation device 12 can be operated from the retracted state or vice versa only by pressing the operation switch 12 once. The electric circuit may be configured to perform the above.
Furthermore, the present invention is not limited to the configurations in the above-described embodiments as long as the characteristic functions of the present invention are not impaired.

It is a side view which shows the main-body part of the hydraulic shovel which is an example of the construction machine to which this invention is applied in the state which lowered the ladder. FIG. 2 is a top view of FIG. 1. It is a side view of the ladder and its attachment part shown in a ladder use state. It is a side view of the ladder and its attachment part shown in the middle of raising and lowering the ladder. It is a side view of a ladder and its attachment part shown in a ladder storage state. It is a rear view of the ladder and its attachment part shown in the ladder use state. It is detail drawing of the lock mechanism used in the state which raised the ladder. FIG. 4 is a hydraulic / electric circuit diagram for driving a hydraulic cylinder that is a power source for raising and lowering a ladder. It is a side view which shows the other Example of this invention.

Explanation of symbols

1: Lifting device 2: First divided ladder 2a: First connecting portion 2b: Second connecting portion 2c, 3a: Steps 2d, 3b: Handrail 3: Second divided ladder 4: Hydraulic cylinder 4a: Hydraulic cylinder Bottom side 4b: Hydraulic cylinder rod side 4c, 4d, 5a, 6a, 6b, 6c, 7a: Connecting part 5: Rod 6, 7: Link 8: Stopper receiver 8a: Pin 9: Stopper 9a: Lever 9b: Lock 9c: Lock rotation point 9d: Spring 9e: Spring support bracket 9f, 10a: Switch member 10, 11: Limit switch 12: Operation switch 13: Alarm buzzer 14: Electric motor 15: Pump 16: Three-position switching valve 16a, 16b: Solenoid 17: Main relief valve 18: Overload relief valve 19: Flow control valve 20: Pump of radiator fan circuit 21: Electricity Valve 22: Orifice 23: Stop valve 24, 25, 26, 27: Check valve 28, 29: Tank 30: Revolving body 31: Driver's cab 31a: Gate lock lever 32: Sidewalk 33: Traveling body 34: Swivel device 38 : Slide ladder 40: Gate lock lever switch 100: Lock mechanism

Claims (5)

A first ladder portion provided on the revolving structure of the construction machine so as to be rotatable in the vertical direction;
A second ladder portion connected to the tip of the first ladder portion so as to be vertically rotatable;
An actuator for rotating the first ladder portion;
A link mechanism that drives the second ladder part to be folded into the first ladder part in conjunction with the movement of the first ladder part driven by the actuator to the retracted state. Lifting device for construction machinery. The lifting device of claim 1,
A lifting device for a construction machine, characterized in that an inclination angle of a ladder portion in use of the lifting device is maintained by the actuator and the link mechanism. The lifting device according to any one of claims 1 and 2,
The actuator is a hydraulic cylinder;
The hydraulic circuit that drives the hydraulic cylinder
A main circuit composed of a first switching valve that determines expansion and contraction operations of the hydraulic pump and the hydraulic cylinder;
A second switching valve that determines whether or not to supply hydraulic pressure of the construction machine drive pump to the hydraulic cylinder, and supplies hydraulic oil to the hydraulic cylinder at least to maintain the stored state when in the stored state A lifting device for a construction machine, wherein the second switching valve is switched as described above . The lifting device according to claim 3,
Means for detecting that the lifting device is in use or retracted;
When the detection means detects a state other than the use state,
Switching the second switching valve, pressure oil is supplied from the construction machine drive pump to the hydraulic cylinder,
When the detection means detects a state other than the storage state,
A lifting device for a construction machine, wherein the swinging operation of the swinging body is disabled. The lifting device according to claim 3,
Interlocking the gate lock lever switch and the operation switch of the lifting device,
A lifting device for a construction machine, wherein the lifting device can be shifted from a retracted state to a used state only when the gate lock is disabled so that the swinging body cannot swing.

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