JP5374207B2 - Work table leveling device and aerial work platform - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leveling device for a work bench, capable of correcting the attitude of the work bench at once, even in a stopped state of an engine. <P>SOLUTION: This leveling device S of the work bench of the high lift work vehicle 1 includes a boom 3 derrickably mounted on a vehicle body 10, the work bench 4 mounted derrickably at a distal end of the boom 3, a leveling cylinder 5 for derricking the work bench 4. The leveling device S further includes normal-use hydraulic pumps 62 and 63 for driving the leveling cylinder 5 by the engine 61, and an electric emergency hydraulic pump 65 for driving only the leveling cylinder 5 when the engine 61 is stopped. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a work table leveling device and an aerial work platform.

  2. Description of the Related Art Conventionally, an aerial work vehicle has a work table attached to the tip of a boom, and an operator can work on the work table. In this aerial work platform, in order for an operator to work stably, a cylinder for maintaining a posture (leveling) is often attached under the work table in order to maintain the posture of the work table.

  For example, Patent Document 1 discloses a work table leveling device in which a power source that supplies power to an actuator, an inclination angle detector that detects an inclination angle of the work table, and a control device are provided on the work table. ing. According to such a configuration, it is possible to easily arrange the hose in the boom, and it is possible to improve responsiveness and followability.

Japanese Patent Laid-Open No. 10-175797

  However, in environments that dislike noise and exhaust gas, such as at night or in residential areas, work with the same posture is often performed for a long time with the engine stopped, and it can be corrected if the posture of the work table is lost. There wasn't.

  Accordingly, an object of the present invention is to provide a work table leveling device capable of correcting the posture of the work table even when the engine is stopped, and an aerial work vehicle including the work table leveling device.

  In order to achieve the above object, a leveling device for a workbench according to the present invention includes a boom that can be raised and lowered on a vehicle body, a workbench that can be raised and lowered at a tip of the boom, and a leveling cylinder that raises and lowers the workbench. And a working hydraulic pump for driving the leveling cylinder by an engine, and an electrically operated emergency pump for driving only the leveling cylinder when the engine is stopped. A hydraulic pump.

  As described above, the leveling device for a workbench according to the present invention includes a service hydraulic pump that drives the leveling cylinder by the engine and an electric emergency hydraulic pump that drives only the leveling cylinder when the engine is stopped. In preparation.

  Accordingly, even when the engine is stopped, the posture of the work table can be corrected by driving the leveling cylinder with the electric emergency pump. For this reason, the safety | security of the worker who is on the worktable can be improved.

It is a block diagram explaining embodiment of this invention. It is explanatory drawing explaining the structure of an aerial work vehicle. It is a hydraulic circuit diagram of the leveling apparatus of a work table.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the overall configuration of an aerial work vehicle 1 provided with a leveling device S for a workbench according to the present invention will be described with reference to FIG. The aerial work vehicle 1 according to the present embodiment is of a type in which the boom 3 is bent into a “<” shape in the middle, but the leveling device of the work table can be applied to a type in which the boom 3 is not bent. is there.

  As shown in FIGS. 1 and 2, an aerial work vehicle 1 of the present invention includes a vehicle body 10 that is a main body portion of a vehicle having a traveling function, a swivel base 2 that is attached to the vehicle body 10 so as to be horizontally turnable, A boom 3 attached to the swivel base 2, a work table 4 attached to the tip of the boom 3, and outriggers 11 provided at four corners of the vehicle body 10 are provided.

  The swivel base 2 has a pinion gear to which the power of a swivel motor 74 that is rotated by hydraulic pressure is transmitted. The pinion gear meshes with a circular gear provided in the vehicle body 10 and rotates around the swivel axis.

  The boom 3 includes, for example, a first boom 31, a second boom 32, a third boom 33, a fourth boom 34, a fifth boom 35, and the like. The first boom 31, the second boom 32, and the third boom 33 can be expanded and contracted by a telescopic cylinder 73 (see FIG. 1) that expands and contracts by hydraulic pressure.

  Further, the first boom 31 on the most proximal side has a proximal end portion rotatably attached by a support shaft installed horizontally on the swivel base 2 so that the first boom 31 can be raised and lowered vertically.

  A hoisting cylinder (hydraulic cylinder) 72 is bridged between the swivel base 2 and the vicinity of the rear end of the first boom 31, and the boom 3 and the work table 4 as a whole are expanded and contracted. Can be undulated.

  Further, a bending cylinder 71 is bridged between the distal end side of the third boom 33 and the proximal end side of the fourth boom 34, and the fourth boom 34 is expanded and contracted by expanding and contracting the bending cylinder 71. The three booms 33 can be relatively raised and lowered.

  Further, a leveling cylinder 5 is bridged between the tip of the fifth boom 35 and the work table 4, and the work table 4 is held horizontally or held in an inclined state by expanding and contracting the leveling cylinder 5. It becomes possible to do.

  The work table 4 is formed in a box shape so that an operator can board and work at a high place, and a leveling cylinder 5 is attached between the work table 4 and the fifth boom 35, The posture (tilt angle) can be controlled.

  In addition, an inclination angle measuring device 66 for measuring the absolute inclination angle (relative to the horizontal) of the work table 4 is attached to the work table 4 (see FIG. 1). The tilt angle measuring device 66 constantly measures the tilt angle of the work table 4 and transmits the measured tilt angle to the control device.

  The outriggers 11 are for preventing the aerial work vehicle 1 from overturning, and are provided on the left and right sides of the vehicle body 10 on the front side and the rear side.

  Next, the configuration of the hydraulic circuit of the leveling device S for the work table built in the vehicle body 10 will be described with reference to FIGS.

  The working table leveling device S according to the present embodiment includes an engine (not shown) serving as a prime mover for traveling, a PTO (power take-off) 61 that extracts rotational power of the engine, and a normal hydraulic pump connected to the PTO 61. The working pump 62 and the leveling pump 63, the leveling cylinder 5 as an actuator group driven by the working pump 62 and the leveling pump 63, the bending cylinder 71, the hoisting cylinder 72, the telescopic cylinder 73, the turning motor 74, and the outrigger 11 are stretched. A slide cylinder 75 to be put out and installed, and a jack cylinder 76, and a work pump 64 and a leveling pump 65 as an emergency hydraulic pump for driving an actuator group when the engine is stopped; Electric motor 7 connected to leveling pump 65 It is configured to include a and.

  The working pump 62 and the leveling pump 63 as the regular hydraulic pump are connected to a PTO 61 coupled to a transmission (not shown) so that the power of the rotating engine can be directly taken out and converted into hydraulic pressure. It has become.

  Further, the work pump 64 and the leveling pump 65 as emergency hydraulic pumps are connected to an electric motor 70 that is installed separately without using the engine drive, so that even when the engine is stopped, the command from the control device In response, hydraulic pressure is generated by the rotational power of the electric motor 70.

  Note that since the electric motor 70 is supplied with electricity from a battery (not shown), it is preferable to use a battery having a larger capacity than usual.

  Further, the leveling cylinder 5 is for raising and lowering the work table 4 relative to the third boom 33 at the most distal end side, and a leveling pump 63 as an ordinary hydraulic pump and an emergency pump via a leveling operation valve 67. It is connected to both of the leveling pump 65 as a hydraulic pump for use.

  The bending cylinder 71 is for turning and bending the fourth boom 34 with respect to the third boom 33, and a work pump 62 as an ordinary hydraulic pump and an emergency hydraulic pressure via a boom operation valve 68. It is connected to both work pumps 64 as pumps.

  Similarly, the hoisting cylinder 72 is for hoisting the booms 31, 32, 33, the telescopic cylinder 73 is for hoisting the booms 31, 32, 33, and the swing motor 74 is used for the boom 3 and the work table. 4 is connected to both a work pump 62 as a normal hydraulic pump and a work pump 64 as an emergency hydraulic pump via a boom operation valve 68, respectively. ing.

  The boom operation valve 68 is a valve group for operating the bending cylinder 71, the hoisting cylinder 72, the telescopic cylinder 73, and the turning motor 74 in response to a command from the control device. It is constituted by a switching valve.

  Further, the slide cylinder 75 is for projecting the outrigger 11, and the jack cylinder 76 is for grounding the outrigger 11 to obtain a reaction force, both of which are serviced hydraulic pumps via the outrigger operation valve 69. And a work pump 64 as an emergency hydraulic pump.

  This outrigger operation valve 69 is a valve group for operating the slide cylinders 75,... And the jack cylinders 76,. .. Are constituted by four electromagnetic switching valves for operating each of the above and one electromagnetic switching valve for switching the circuit on the boom operation valve 68 side.

  Next, the operation of the leveling device S for a work table according to the present embodiment will be described. The automatic posture correction control described below is executed in the control device.

  First, an operator gets on the work table 4 while the work table 4 is stored in the vehicle body 10 and the outriggers 11 are grounded. Then, the operator operates the operation panel of the work table 4 to move the work table 4 to the target position by turning, raising and lowering and extending the boom 3.

  Since the engine is driven until the work table 4 reaches the work position in this way, the rotational driving force of the engine is taken out by the PTO 61 and the boom 3 is turned by the work pump 62 as a normal hydraulic pump. -Make ups and downs.

  Further, although the posture of the work table 4 is maintained substantially horizontal by the leveling cylinder 5 even if the posture of the boom 3 is changed, the hydraulic pressure is also supplied to the leveling cylinder 5 by a leveling pump 63 as a normal hydraulic pump. Yes.

  Next, when the work table 4 reaches the target position, the operator operates the operation panel on the work table 4 to stop the engine in order to suppress generation of noise and exhaust gas caused by continuing to drive the engine. . Then, the worker works for a long time while on the work table 4. Note that the control device functions even when the engine is stopped.

  When a leak occurs in the counter balance valve of the bending cylinder 71, the counter balance valve of the hoisting cylinder 72, the counter balance valve of the leveling cylinder 5, etc., the inclination angle of the work table 4 changes.

  This change in the tilt angle is measured by the tilt angle measuring device 66 that is constantly monitored, and the measured tilt angle is notified to the control device. When the amount of change in the tilt angle is equal to or greater than a predetermined allowable change angle (for example, the change in angle is about 4 degrees), the control device automatically determines that the state is abnormal.

  Note that the change amount of the tilt angle is measured by a difference (increase / decrease amount) from the reference angle by using an absolute tilt angle when the engine is stopped or a preset tilt angle as a reference angle.

  The control device determined to be in the abnormal state drives the electric motor 70 to generate hydraulic pressure by the leveling pump 65 as an emergency hydraulic pump.

  Here, it is desirable to drive only the leveling pump 65 with the electric motor 70, but even when the work pump 64 is simultaneously driven with the circuit configuration shown in FIG. 3, the unloading solenoid 81 is controlled by the control device. The working oil sent from the work pump 64 in the OFF state is returned to the tank 60 in a short-circuit manner, so that the work pump 64 is driven with no load, and the working oil is supplied only to the hydraulic circuit on the leveling cylinder 5 side. be able to.

  Here, since the unloading solenoid 82 of the leveling cylinder 5 remains in the ON state and the circuit is connected, the hydraulic oil fed by the emergency leveling pump 65 flows into the leveling cylinder 5 side.

  And the inclination of the work table 4 is corrected to the reference angle by adjusting the amount of expansion / contraction of the leveling cylinder 5 by driving the leveling operation valve 67 under the command of the control device.

  In addition, according to the circuit configuration of FIG. 3, even when an unload failure of the unload solenoid 81 and an operation failure of the boom operation valve 68 occur, it is possible to reliably return only leveling.

  Next, the effects which the leveling apparatus S of the worktable of this invention has are enumerated below.

  (1) The working table leveling device S of the present invention includes a boom 3 that can be raised and lowered on the vehicle body 10, a work table 4 that can be raised and lowered at the tip of the boom 3, and a leveling cylinder 5 that raises and lowers the work table 4. And have.

  Therefore, when the engine is driven, the operator can correct the inclination of the work table 4 by operating the operation panel of the work table 4 and operating the regular hydraulic pump through the PTO 61.

  In addition to the regular hydraulic pump that drives the leveling cylinder 5 by the engine, a leveling pump 65 is provided as an electric emergency hydraulic pump that drives the leveling cylinder 5 when the engine is stopped.

  Therefore, even when the engine is stopped, the posture of the work table 4 can be corrected by expanding and contracting the leveling cylinder 5 by the leveling pump 65 as an emergency pump operated by the electric motor 70.

  Thus, if the posture of the tilted work table 4 is corrected, the safety can be improved.

  Furthermore, if it is possible to work safely without starting the engine, the engine is turned off even when working for a short time, and energy loss is further reduced and noise can be suppressed.

  In addition, since the case where leak (leakage) of hydraulic fluid occurs is generally assumed as a factor that increases the inclination angle as described above, the leveling operation may be slow. Therefore, the leveling cylinder 5 is connected to the leveling pump. When operating exclusively for 65, energy loss can be further reduced by using the small-capacity electric motor 70 and leveling pump 65.

  (2) Further, the work table 4 is provided with an inclination angle measuring device 66 for measuring the inclination angle, and when the amount of change in the inclination angle after the engine is stopped becomes equal to or greater than a predetermined allowable change angle, The leveling cylinder 5 is driven by a leveling pump 65 as an emergency hydraulic pump, and the work table 4 is returned to a preset inclination angle.

  For this reason, even if the amount of change in the inclination angle of the work table 4 increases without the operator's knowledge, the change in the inclination angle is measured very quickly by the inclination angle measuring device 66 that constantly monitors the inclination angle. The tilt angle can be corrected automatically and reliably by the control device.

  (3) Furthermore, the work pump 64 as an emergency hydraulic pump for driving the boom 3 and the leveling pump 65 as an emergency hydraulic pump for driving the leveling cylinder 5 are driven by the electric motor 70 and the work pump 65 is not used. An unloading solenoid 81 for driving with a load is provided.

  Therefore, even if an electric motor is not prepared for the leveling cylinder 5, by using the electric motor 70 that drives the work machines such as the boom 3 and the outriggers 11 in an emergency, the mounting space and cost can be reduced. Can be suppressed.

  (4) The aerial work vehicle 1 according to the present embodiment is provided with the above-described work table leveling device S, so that the work vehicle 1 can be a safe aerial work vehicle 1 that can correct the inclination of the work table 4 even when the engine is stopped.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are not limited to the present invention. included.

  For example, in the embodiment, the case where the emergency hydraulic pump has the electric motor 70 connected to both the work pump 64 and the leveling pump 65 has been described. However, the invention is not limited to this, and the leveling is performed as described above. You may have an electric motor connected only to the pump 65. FIG.

  In the above-described embodiment, the case where the automatic posture correction control is performed when the change amount of the inclination angle is equal to or larger than the predetermined allowable change angle is described. The automatic posture correction control may be performed when the absolute inclination angle is equal to or greater than a predetermined range based on a simple inclination angle.

DESCRIPTION OF SYMBOLS Leveling device 1 of work bench 10 Work place 10 in a height body 2 Swivel 3 Boom 4 Work 5 Leveling cylinder 61 PTO
62 Working pump (ordinary hydraulic pump)
63 Leveling pump (normal hydraulic pump)
64 Working pump (Emergency hydraulic pump)
65 Leveling pump (emergency hydraulic pump)
66 Inclination angle measuring device 70 Electric motor 71 Bending cylinder 72 Undulating cylinder 81, 82 Solenoid for unloading

Claims (4)

A leveling device for a work platform of an aerial work platform, comprising: a boom that can be raised and lowered on a vehicle body; a worktable that can be raised and lowered at a tip of the boom; and a leveling cylinder that raises and lowers the worktable;
A working table leveling apparatus comprising: a service hydraulic pump that drives the leveling cylinder by an engine; and an electric emergency hydraulic pump that drives only the leveling cylinder when the engine is stopped. An inclination angle measuring device for measuring an inclination angle is installed on the work table, and when the change amount of the inclination angle after the engine is stopped is equal to or greater than a predetermined allowable change angle,
2. The leveling device for a workbench according to claim 1, wherein the leveling cylinder is driven by the emergency hydraulic pump, and the workbench is returned to a preset inclination angle.   An emergency hydraulic pump electric motor for driving the boom is provided. The emergency hydraulic pump for driving the leveling cylinder is driven by the electric motor, and an unloading solenoid for disconnecting the hydraulic circuit on the boom side is provided. The work table leveling device according to claim 1, wherein the leveling device is provided.   An aerial work vehicle comprising the work table leveling device according to any one of claims 1 to 3.

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