JP2017171487A - High-place work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-place work vehicle that is capable of appropriately detecting a distance between a work bench and an upper structure and preventing the work bench from excessively approaching to the upper structure.SOLUTION: This high-place work vehicle is provided with: a projector 31 that is provided at one end of a work bench 20 and that radiates a light L in a direction roughly parallel to a floor surface at the prescribed height position of the work bench 20 from the floor surface; and a light receiver 32 that is provided at the other end of the work bench 20 and that can receive the light L radiated from the projector 31, and configured such that when the amount of light L received by the light receiver 32 becomes equal to or less than a prescribed level while the light L is radiated from the projector 31, the operation of a book 5 or the like in the approaching direction of the work bench 20 to an upper structure K is regulated, and an alarm is issued from an alarm device.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an aerial work vehicle including a work table that is moved up and down by a lifting device provided on a vehicle body.

  As an example of an aerial work vehicle, there is known an aerial work vehicle that is configured on the basis of a track vehicle that can travel and is configured by mounting a work device on the vehicle body. This working device includes a swivel that is horizontally turnable on a vehicle body, a telescopic boom that is pivotably connected to the swivel, and a pivot that can swing up and down at the tip of the boom. Some of them are configured to have a vertical post that is held vertically regardless of the boom undulation angle and a work table that is attached to the vertical post in a horizontal state. Further, instead of a swivel base and a boom, there is a structure having a vertical mast or scissor link mechanism that can extend and contract in the vertical direction and vertically moving a work table attached to the upper part thereof.

  Such an aerial work vehicle is used in various work sites such as electric wire construction, maintenance inspection work in a road tunnel, and maintenance inspection work of a bridge. For example, when working on an upper structure such as a ceiling in a road tunnel or a lower surface of a bridge, the work table is moved up and down so as to approach the upper structure. At this time, if the work table is too close to the upper structure, there is a risk that an operator may be caught between the work table and the upper structure. Therefore, it is equipped with a distance sensor that detects the distance between the work table and the upper structure by irradiating light upward from the work table and detecting the light reflected by the upper structure, and the work table approaches the upper structure. An aerial work vehicle configured to restrict the movement of the workbench in a direction approaching the upper structure and to warn with a buzzer or the like is known (for example, Patent Document 1). See).

JP 2013-52948 A

  By the way, as described above, in the configuration in which the distance between the work table and the upper structure is detected by irradiating light upward from the work table and detecting the light reflected by the upper structure, for example, the lower surface of the bridge, etc. When there are many irregularities like this, the distance between the work table and the upper structure cannot be detected properly, so that the work table is too close to the upper structure, or in some cases the work table and the upper structure There was a problem of contact with.

  The present invention has been made in view of such problems, and even when the upper structure has many irregularities, the distance between the work table and the upper structure can be appropriately detected. An object of the present invention is to provide an aerial work vehicle that can prevent the vehicle from being too close to the upper structure.

In order to solve the above-described problems, an aerial work vehicle according to the present invention includes a vehicle body that can travel, and an elevating device provided on the vehicle body (for example, the swivel base 4, the boom 5, the bending post 6, and the post 10 in the embodiment). ), A work table attached to the lifting device and moved up and down, an operation means provided on the work table for operating the lifting device, and an operation signal from the operation means based on the operation signal Operation control means for controlling the operation of the lifting device. In addition, a light projecting unit that is provided at one end of the work table and that emits light in a direction substantially parallel to the floor surface at a predetermined height from the floor surface of the work table, and the work table A light receiving means that can receive the light emitted from the light projecting means, and the light received by the light receiving means when the light is emitted from the light projecting means. Alarm means (for example, the controller 70 and the alarm device 80 in the embodiment) is configured to perform an alarm operation when the amount of is less than a predetermined level.

  In the aerial work vehicle having the above-described configuration, the work table is configured to be able to enlarge and reduce the width of the floor surface in a predetermined direction, and the light projecting unit is provided on one end side of the work table in the enlargement / reduction direction. The light receiving means is preferably provided on the other end side in the enlargement / reduction direction.

  In the aerial work vehicle having the above configuration, the light projecting unit is configured to be able to adjust a height position of the light to be irradiated from the floor surface, and the light receiving unit is a part of the floor surface that receives the light. It is preferable that the height position from can be adjusted.

  In the aerial work vehicle having the above-described configuration, the operation means includes an operation lever operated by an operator's hand and a foot switch operated by a foot, and only when the foot switch is turned on. An operation signal from the operation lever is configured to be transmitted to the operation control unit, and the light projecting unit is controlled to emit the light only when the foot switch is turned on. preferable.

  In the aerial work vehicle having the above-described configuration, it is preferable that the light projecting unit is controlled to emit the light when a traveling work state of the vehicle is detected.

  According to the aerial work vehicle according to the present invention, the light in a direction substantially parallel to the floor surface at a predetermined height position from the floor surface of the work table from the light projecting means provided at one end of the work table. And the light receiving means provided at the other end of the work table receives the light, and when the light is emitted from the light projecting means, the light receiving means receives the light. An alarm is activated when the amount falls below a predetermined level. Therefore, even when the upper structure has many irregularities, the convex portion (lowermost end portion) of the upper structure enters between the light projecting means and the light receiving means to block the light from the light projecting means, Since the amount of light received by the light receiving means decreases, it is possible to detect that the upper structure has approached the height position of the light emitted from the light projecting means. At this time, by performing an alarm operation, it is possible to prevent the work table from being brought too close to the upper structure. In this specification, the alarm operation is an operation including an operation that regulates the operation of the lifting device (the operation that moves the work table in a direction approaching the upper structure) and the operation that performs an alarm using a buzzer or a lamp. Means.

  In addition, the work table is configured to be able to scale the floor area in a predetermined direction, the light projecting means is provided on one end side in the enlargement / reduction direction in the work table, and the light receiving means is the other end side in the enlargement / reduction direction. If it is set as the structure provided in, it can detect that the upper structure approached by the light projection means and the light-receiving means in any state where the work table is enlarged or reduced.

  Further, if the height position of the light irradiated from the floor of the work table from the floor surface is adjustable, the work table and the upper structure can be adjusted by adjusting the light irradiation position (height position). The accessible distance can be changed.

Further, if the light projecting means is controlled to emit light only when the foot switch in the operating device is turned on, the light projecting means is used only when the work table is moved up and down by the lifting device. It is possible to detect that the upper structure has approached by the means and the light receiving means. In addition, light is not emitted from the light projecting means when the work table is not moved up and down, so that it is possible to prevent a situation in which an operator being inspected is erroneously detected and an alarm is activated (alarm by buzzer or lamp). Can do.

  Further, if the light projecting means is controlled to emit light when the traveling work state of the vehicle is detected, the foot switch is turned on when performing inspection work while the vehicle is traveling. Even when it is not, the approach between the work table and the upper structure can be detected by the light projecting means and the light receiving means. Then, by performing an alarm operation (alarm by a buzzer, a lamp, or the like), it is possible to notify the worker during the inspection work or the driver of the vehicle of the approach between the work table and the upper structure. In this specification, the vehicle traveling work state refers to a state in which the vehicle side brake is turned off and the braking of the wheels is released, or power for taking out the power of the engine mounted on the vehicle for driving the lifting device. This means a state in which it is possible to work while the vehicle is running, including a state in which the take-off mechanism is turned off and driving of the lifting device is stopped.

It is a side view of a bridge inspection vehicle which is an example of an aerial work vehicle according to the present invention. It is a block diagram which shows the control system of the said bridge inspection vehicle. It is a rear view (partial sectional view) showing an inspection work state of the bridge inspection vehicle. It is a top view which shows the structure of the work stand of the said bridge inspection vehicle. It is a rear view (partial sectional view) showing a state where the work table and the upper structure are close to each other. It is a rear view (partial sectional view) showing another state where the work table and the upper structure are close to each other.

  Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a bridge inspection vehicle that is an example of an aerial work vehicle according to the present invention will be described. As shown in FIG. 1, the bridge inspection vehicle 1 is configured with a truck vehicle as a base, and can run with wheels 3 a and 3 b provided at both left and right ends of the front and rear of the vehicle body 2. A driving cab 2a is provided.

  Roller jacks 17 are provided on the front, rear, left and right of the vehicle body 2. The roller jack 17 includes an outrigger 17a (see FIG. 3) that can be widened in the left-right direction of the vehicle body, a jack 17b that can be expanded and contracted in the vertical direction, and a roller 17c that is rotatably attached to the lower end of the jack 17b. Configured. In the bridge inspection vehicle 1, by extending the outrigger 17a and grounding the roller 17c to the road surface, the vehicle can be operated while the work table 20 described later is moved to a desired position. Yes. The operation of the roller jack 17 is performed by operating a jack operating lever (not shown) provided on the vehicle body 2.

  A swivel base 4 is attached to the rear part of the vehicle body 2 so as to be horizontally swivelable. The swivel base 4 is configured to be turnable by a turning motor 51 built in the vehicle body 2. On the upper part of the swivel base 4, a boom 5 whose base part is pivotably pivoted is attached. The boom 5 is configured to be movable up and down by a boom raising and lowering cylinder 52 straddled between the swivel base 4 and the boom 5. Further, the boom 5 is configured to be telescopically movable by combining the base end boom 5a and the front end boom 5b from the base end side in a telescopic manner, and is configured to be extendable and retractable by a built-in boom telescopic cylinder 53.

A bending / extending post 6 is pivotally connected to the tip of the tip boom 5b so as to be swingable up and down, and a link arm 7 is pivotally connected to the swinging shaft of the bending / extending post 6. A rod-side end of a post-leveling cylinder 54 is pivoted to the upper end of the link arm 7, and a bottom-side end of the cylinder 54 is pivoted into the tip boom 5b. A rod-side end of a post hoisting cylinder 55 is pivotally connected to the lower end of the link arm 7, and a bottom-side end of the cylinder 55 is pivotally connected to a lower portion of the bending / extending post 6. A post 10 is attached to the tip end portion of the bending post 6.

  The bending post 6 can swing up and down with respect to the tip boom 5b by a post hoisting cylinder 55, and the post 10 can be set at a desired bending angle position. The bottom-side oil chamber of the post-leveling cylinder 54 and the rod-side oil chamber of the boom hoisting cylinder 52 are connected by an oil passage to constitute a so-called hydraulic circuit type leveling mechanism, and the boom 5 is raised (inclined). In this case, the bending post 6 is tilted (raised) through the link arm 7 and the post hoisting cylinder 55 by the same angle as the hoisting angle of the boom 5 so that the post 10 is always constant regardless of the hoisting angle of the boom 5. It is configured to be held at an angle (the post 10 is always kept vertical during normal operation).

  The post 10 includes a holder 10h fixed to the bending / extending post 6, and a first post 10a, a second post 10b, a third post 10c, and a fourth post 10d that are nested in the holder 10h. Composed. The post 10 includes a first lifting cylinder 56 straddled between the holder 10h and the first post 10a, and a post telescopic cylinder (not shown) disposed inside the post, with respect to the holder 10h. The four posts 10a to 10d are configured to be movable. An arm 11 is pivotally connected to the tip of the fourth post 10d so as to be pivotable about an axis extending in the front-rear direction in the state shown in FIG. 1, and the arm 11 can be pivoted by an arm pivot cylinder (not shown). It is configured. Note that the turning operation of the arm 11 is allowed only when the post 10 is in a horizontal state, and is specifically used when working at a high place or when the work table 20 is stored on the vehicle body 2.

  A swing base 12 is pivotally connected to the tip of the arm 11 so as to be swingable up and down, and a work table leveling cylinder 57 is straddled between the arm 11 and the swing base 12. A worktable bracket 13 is attached to the swivel base 12 so as to be able to swivel about an axis extending vertically in the state shown in FIG. 1. The worktable bracket 13 is attached to the swivel base 12 by a built-in worktable swivel motor 59. It is configured to be able to turn (swing). A work table 20 is attached to the lower end of the work table bracket 13. The work table leveling cylinder 57 is controlled in its expansion and contraction operation based on a detection signal from an inclination detector provided on the work table 20, and the work table 20 is provided with the work table 20 regardless of the undulation angle of the boom 5 or the bending angle of the post 10. Leveling control is performed so that the floor surface is always maintained in a horizontal state (the worktable bracket 13 is always in a vertically extending state).

  The work table 20 includes a base end deck 21a, an intermediate deck 21b, and a front end deck 21c that are telescopically combined from the work table bracket 13 side, and can be expanded and contracted in a direction perpendicular to the pivot axis of the work table bracket 13. The floor area of the work table 20 can be expanded and reduced by moving the intermediate deck 21b and the front end deck 21c relative to the base end deck 21a by the deck expansion / contraction cylinder 58.

  As shown in FIGS. 3 and 4, the base deck 21a, the intermediate deck 21b, and the front deck 21c are rectangular work floors 22a, 22b, and 22c, respectively, on which the operator can ride, and the upper surfaces of these work floors. It has handrails 23a, 23b, and 23c that are erected so as to surround the periphery. In the present embodiment, the three-stage work table 20 including the base end deck 21a, the intermediate deck 21b, and the front end deck 21c is illustrated. However, for example, the work floor area is constant (a configuration that does not expand and contract). A configuration having a work table or a work table having two or more stages may be used.

  The work table 20 is provided with an operation device 40 that is operated by a boarded worker. As shown in FIG. 2, the operation device 40 includes a boom operation lever 41 for performing the hoisting, extending and retracting and turning operations of the boom 5, and a post operating lever 42 for performing the hoisting (bending and stretching) and extending and retracting operations of the post 10. And a work table operation lever 43 for turning (swinging) and expanding / contracting the work table 20. The operator manually operates these operation levers 41 to 43, so that the boom hoisting cylinder 52, the boom telescopic cylinder 53, the swing motor 51, the post hoisting cylinder 55, the post lifting cylinder 56, the worktable swing motor 59, and the work are performed. Each operation of the table expansion / contraction cylinder 58 can be performed.

  The vehicle body 2 is provided with a traveling engine E, a hydraulic pump P, and a power take-off mechanism PTO that extracts the driving force of the engine E and drives the hydraulic pump P. A PTO operation lever 15 for turning on / off the power take-off mechanism PTO (driving or stopping the hydraulic pump P) is provided in the driving cab 2a. The swing motor 51, the hoisting cylinder 52, the boom telescopic cylinder 53, the post hoisting cylinder 55, the post lifting cylinder 56, the worktable expansion / contraction cylinder 58, and the worktable turning motor 59 are supplied with hydraulic oil discharged from the hydraulic pump P, respectively. It is supplied via control valves V1 to V7 corresponding to the hydraulic actuator. Each of these hydraulic actuators is operated at a direction and speed corresponding to the driving state of the spool of the corresponding control valve.

  The vehicle body 2 is provided with a controller 70, and the valve control unit 71 of the controller 70 is a control valve based on an operation signal output according to the operation state (operation direction and operation amount) of the boom operation lever 41. The spools V1 to V3 are driven, and the spools of the control valves V4 and V5 are driven based on the operation signal output according to the operation state of the post operation lever 42, and according to the operation state of the worktable operation lever 43. The spools of the control valves V4 and V5 are driven based on the operation signal output in this manner. The operation states (operation direction and operation amount) of the boom operation lever 41, the post operation lever 42, and the worktable operation lever 43 are detected by lever operation state detectors 41a, 42a, 43a (for example, configured by a potentiometer), The detection signal is input to the valve control unit 71 as an operation signal corresponding to the operation direction and the operation amount of the operation levers 41 to 43.

  The operating device 40 is provided on the floor surface of the work table 20 and includes a pedal-type foot switch 45 that is operated by an operator who has boarded the work table 20 with his / her foot. The foot switch 45 is a switch that permits the operation of each hydraulic actuator by the operation of the boom operation lever 41, the post operation lever 42, and the work table operation lever 43 only when the operator depresses with a foot and is turned on. The switch operation signal is output in the depressed on-operation state, and the switch operation signal is not output in the off-operation state (non-operation state) in which the depression is released. The switch operation signal output from the foot switch 45 is input to the valve control unit 71 of the controller 70, and the valve control unit 71 receives the boom operation lever 41 and the post only when the switch operation signal is input from the foot switch 45. Each operation signal output by the operation of the operation lever 42 and the work table operation lever 43 is treated as effective, and the spool of each control valve is driven based on each operation signal to operate each hydraulic actuator. It is configured.

  The bridge inspection vehicle 1 configured as described above includes a safety device for preventing an accident in which an operator is caught between the work table 20 and the upper structure during the inspection work. This safety device will be described below. The safety device has a workbench approach detection device 30 that detects that the workbench 20 has approached the upper structure, a controller 70, and alarm devices 80 provided in the workbench 20 and the driving cab 2a, respectively. Configured. The alarm device 80 includes an alarm buzzer 81, an alarm lamp 82, and an alarm display display 83, and is configured to notify the worker of the danger visually or by hearing.

  As shown in FIGS. 3 and 4, the workbench approach detection device 30 includes a light projector 31 provided at the distal end portion of the distal end deck 21c of the worktable 20, and a light receiver provided at the proximal end portion of the proximal end deck 21a. 32. The projector 31 is fixed to the distal end portion of a rod-shaped holding member 33 that is configured to be extendable and contracted, and is disposed at a predetermined height position from the work floor 22c of the tip deck 21c, and is in a direction substantially parallel to the work floor 22c (work It is configured to irradiate the light L toward the base deck 21a side in the expansion / contraction direction of the table 20. The projector 31 can adjust the height position of the projector 31, that is, the height position of the light L to be irradiated, by expanding and contracting the holding member 33. The light receiver 32 is fixed to the distal end portion of a rod-shaped holding member 34 that is configured to be extendable and retractable in the same manner as the holding member 33, and is at a height position (and front and rear, left and right) that can receive the light L emitted from the projector 31. Position). The height position of the light receiver 32 can also be adjusted by expanding and contracting the holding member 34. The holding members 33 and 34 are provided with springs therein, and when the force is released from the contracted state, the holding members 33 and 34 are restored to their original lengths by the springs.

  As shown in FIG. 4, the projector 31 is disposed at an end portion in a direction orthogonal to the expansion / contraction direction of the work table 20 in the front end deck 21 c (work floor 22 c) in plan view. The light receiver 32 is disposed at the end of the base deck 21a (work floor 22a) in the orthogonal direction. Accordingly, the light L irradiated from the projector 31 reaches the light receiver 32 through the upper portions of the handrails 23c, 23b, and 23a, and an operator who moves on the work floors 22a to 22c is concerned with the light. A light projector 31 and a light receiver 32 are arranged so as not to block L. In addition, the projector 31 and the light receiver 32 are respectively disposed at both ends of the work table 20 in the orthogonal direction, and the work table approach detection device 30 includes two sets of the light projector 31 and the light receiver 32. Yes.

  As shown in FIG. 2, the light projector 31 and the light receiver 32 are electrically connected to the controller 70, and when the light L emitted from the light projector 31 is detected in the light receiver 32, the detection signal (light quantity information value) is detected. ) Is input to the controller 70. Further, the controller 70 is electrically connected to the PTO operation lever 15 and the side brake lever 16 (parking brake lever) in the driving cab 2 a and the foot switch 45 of the operation device 40. The controller 70 is configured to perform control to irradiate the light L from the projector 31 only when the foot switch 45 is depressed and turned on and a switch operation signal is input from the foot switch 45. Even when the foot switch 45 is not turned on, the controller 70 turns off the PTO operation lever 15 to stop the hydraulic pump P and turns off the side brake lever 16 to turn off the parking brake. Thus, when the braking of the wheels 3a and 3b of the vehicle body 2 is released and a signal indicating a state in which the work can be performed while the vehicle is running is input, control to irradiate the light L from the projector 31 is performed. It is configured.

  The controller 70 includes an alarm determination unit 72 and an alarm release unit 73 in addition to the valve control unit 71 described above. Based on the detection signal (light quantity information value) input from the light receiver 32, the alarm determination unit 72 causes the work table 20 to approach the upper structure K below a predetermined alarm distance, as will be described later. It is determined whether or not it is in a state. Then, when the alarm determination unit 72 determines that the workbench 20 is in a state of approaching the upper structure K, the operation restriction of the boom 5, the extension post 6 and the post 10 and the alarm operation by the alarm device 80 are performed. Is configured to run.

As shown in FIG. 3, when the work table 20 is separated from the upper structure K by a predetermined warning distance D, the light L emitted from the projector 31 may be blocked by the upper structure K. Therefore, the light L is received by the light receiver 32. Therefore, the alarm determination unit 72 receives the light L having a light amount equal to or higher than a predetermined level based on the detection signal input from the light receiver 32 when the light L is emitted from the projector 31. It is configured to determine that the work table 20 is further than the warning distance D with respect to the upper structure K when the present state is detected. At this time, the alarm determination unit 72 does not execute the operation regulation of the boom 5 or the like and the alarm operation by the alarm device 80. The alarm distance D is a distance corresponding to the height position of the light L emitted from the projector 31 from the work floors 22c and 22a, and an operator is sandwiched between the work table 20 and the upper structure K. It is set so that a certain level of safe space can be secured. The alarm distance D can be adjusted by adjusting the height positions of the light projector 31 and the light receiver 32 by expanding and contracting the holding members 33 and 34 as described above.

  As shown in FIG. 5, when the work table 20 approaches the upper structure K below the alarm distance D, the light L emitted from the projector 31 is a convex portion such as a steel frame on the lower surface of the upper structure K. Therefore, the light L does not reach the light receiver 32, or the light amount of the light L reaching the light receiver 32 decreases to a predetermined level or less. In addition, as shown in FIG. 6, when the work table 20 approaches the upper structure K below the alarm distance D and the convex portion on the lower surface of the upper structure K contacts the upper surface of the projector 31. Since the holding member 33 that holds the projector 31 is reduced and the height position of the projector 31 is lowered, the light L emitted from the projector 31 does not reach the light receiver 32.

  Accordingly, the warning determination unit 72 reduces the light amount of the light L received by the light receiver 32 to a predetermined level or more based on the detection signal input from the light receiver 32 when the light L is emitted from the projector 31. When the detected state is detected, it is determined that the work table 20 is in a state of approaching the upper structure K below the predetermined alarm distance D. Then, the alarm determination unit 72 regulates the operation in the direction in which the work table 20 is brought closer to the upper structure K among the collapse and extension operations of the boom 5, the undulation (bend and extension) operation of the bending and stretching posts 6, and the expansion and contraction operations of the posts 10. The control signal is output to the valve control unit 71 so as to restrict (forcibly stop) the operation. At this time, the valve controller 71 operates the boom 5, the bent post 6, and the post 10 in a direction to bring the work table 20 closer to the upper structure K by operating the boom operation lever 41 and the post operation lever 42. However, the operation signal is ignored (or the supply of hydraulic oil to each hydraulic actuator is cut off so that the boom 5, the bending post 6 and the post 10 are not operated), whereby the boom 5, the bending post 6 and the post 10 are configured to be regulated.

  In addition, when the alarm determination unit 72 determines that the work table 20 is in a state of approaching the alarm distance D or less with respect to the upper structure K as described above, the alarm determination unit 72 is provided in the work table 20 and the operation cab 2a. An alarm activation signal is output to the alarm device 80, and the operator is notified that the work table 20 is in the state of approaching the upper structure K by the alarm buzzer 81, the alarm lamp 82, and the alarm display display 83 of the alarm device 80. . Note that the alarm determination unit 72 is in a state where the work table 20 is close to the upper structure K below the alarm distance D, that is, until the work table 20 is further away from the upper structure K than the alarm distance D. The alarm operation signal is self-held and the alarm operation by the alarm device 80 is continued.

The alarm release unit 73 is electrically connected to an alarm release switch 46 provided in the operating device 40, and an alarm release signal is input only when the alarm release switch 46 is turned on. Yes. The alarm release switch 46 is constituted by a momentary switch, and is configured to automatically return to the neutral position and to be turned off when the operation is released. The alarm canceling unit 73 is operated by the alarm determining unit 72 when the operation of the boom 5, the extension post 6 and the post 10 in the direction in which the work table 20 is brought closer to the upper structure K, and the alarm operation by the alarm device 80 are performed. When the alarm canceling signal is received from the alarm canceling switch 46, a canceling signal for canceling the operation restriction of the boom 5, the bending post 6 and the post 10 is output to the valve control unit 71, and the work table 20 is brought close to the upper structure K. The directional boom 5, the bent post 6 and the post 10 are configured to be allowed to operate. At this time, the valve control unit 71 operates the boom 5, the bending post 6 and the post 10 at a lower speed than usual. Moreover, the warning judgment part 72 alerts that the upper structure K is in the close state by changing the warning sound and warning display of the warning action by the warning device 80.

  According to the safety device for the work table 20 configured as described above, the floor 31 (work floor) of the work table is projected from the projector 31 provided at one end of the work table 20 at a predetermined height position. The light L in the direction substantially parallel to the surface is irradiated, and the light receiver 32 provided at the other end of the work table receives the light L. When the light L received by the light projector 31 falls below a predetermined level when the light L is irradiated from the projector 31, the boom 5 and the bending post 6 in the direction in which the work table 20 is brought closer to the upper structure K. In addition, the operation restriction of the post 10 and the alarm operation by the alarm device 80 are performed. Therefore, even when the upper surface of the upper structure K has many irregularities, the convex portion (lowermost end portion) of the upper structure K enters between the light projector 31 and the light receiver 32 and the light L from the light projector 31 is emitted. Since the amount of light received by the light receiver 32 is reduced by blocking, it is possible to detect that the upper structure K has approached the height position of the light L emitted from the light projector 31. At this time, it is possible to prevent the work table 20 from being too close to the upper structure K by restricting the operation of the boom 5, the bent post 6 and the post 10, and performing an alarm operation by the alarm device 80.

  Further, the work table 20 is configured to be able to scale the floor area in a predetermined direction, the projector 31 is provided on one end side of the work table 20 in the enlargement / reduction direction, and the light receiver 32 is arranged in the other direction of the enlargement / reduction. It is provided on the end side. Therefore, it is possible to detect that the upper structure K has approached by the light projector 31 and the light receiver 32 in any state where the work table 20 is enlarged or reduced.

  Further, the projector 31 is configured to be able to adjust the height position of the irradiated light L from the floor surface of the work table 20 by expanding and contracting the holding member 33. Therefore, the holding members 33 and 34 are expanded and contracted to adjust the height positions of the light projector 31 and the light receiver 32, that is, the height position of the light L emitted from the light projector 31. The accessible distance (alarm distance D) can be changed. In addition, when the upper structure K comes into contact with the upper surface of the projector 31 or the light receiver 32, the holding members 33 and 34 are reduced, and the height position of the projector 31 or the light receiver 32 is changed. Since the received light L cannot be received by the light receiver 32, it is possible to detect that the upper structure K has approached. In addition, since the holding members 33 and 34 are reduced when the upper structure K comes into contact with the upper structure K, it is possible to prevent the light projector 31 or the light receiver 32 from being crushed and damaged. When the contact with the upper structure K is released, the holding members 33 and 34 are restored to their original lengths by the springs provided inside the holding members 33 and 34, so that the projector 31 or the light receiver 32 can be restored to its original height position.

  Further, the projector 31 is configured to perform control to irradiate the light L from the projector 31 only when the foot switch 45 in the operation device 40 is turned on. Therefore, only when the work table 20 is moved up and down by the operation of the operation device 40, it is possible to detect that the upper structure K is approached by the light projector 31 and the light receiver 32. Further, since the light L is not emitted from the projector 31 when the work table 20 is not moved up and down, it is possible to prevent a situation in which an operator during inspection work is erroneously detected and an alarm is activated (alarm by a buzzer, a lamp, or the like). be able to.

Further, the PTO operation lever 15 is turned off to stop the hydraulic pump P, and the side brake lever 16 is turned off to release the braking of the wheels 3a and 3b of the vehicle body 2 by the parking brake, while running the vehicle. When a state in which work can be performed is detected, control is performed to irradiate the light L from the projector 31. Therefore, when performing inspection work while driving the vehicle, even when the foot switch 45 is not turned on, the approach of the work table 20 and the upper structure K is detected by the projector 31 and the light receiver 32. Can do. Then, by performing an alarm operation (alarm by a buzzer, a lamp, or the like) by the alarm device 80, it is possible to notify the worker who is performing the inspection work or the driver of the vehicle of the approach of the work table 20 and the upper structure K. .

  Although the embodiment according to the present invention has been described so far, the scope of the present invention is not limited to that shown in the above-described embodiment. For example, in the above-described embodiment, the light projector 31 and the light receiver 32 are fixed to the distal end portions of the holding members 33 and 34, and the height position of the light L emitted from the light projector 31 is expanded and contracted. For example, a plurality of light projectors 31 and light receivers 32 are disposed in the height direction, and the light L is switched by switching the light projector 31 that emits the light L from the plurality of light projectors 31. The height position (alarm distance D) may be adjusted.

  Further, in the above-described embodiment, two sets of the projector 31 and the light receiver 32 are arranged on both sides of the work table 20, but one set or three or more sets of the projector 31 and the light receiver 32 are arranged. May be. In the above-described embodiment, an example in which the present invention is applied to a bridge inspection vehicle has been described. However, the present invention is a high-speed moving up and down work platform by a vertically-movable vertical mast provided on a vehicle body. The present invention can be applied to various aerial work vehicles such as an aerial work vehicle and an aerial work vehicle in which a work platform is moved up and down by a scissor link mechanism provided on the vehicle body.

1 Bridge inspection vehicle (aerial work vehicle)
2 Body 4 Turntable (lifting device)
5 Boom (elevating device)
6 Stretching post (lifting device)
10 Post (elevating device)
20 Working table 31 Floodlight (lighting means)
32 Light receiver (light receiving means)
40 Operating device 45 Foot switch 70 Controller 71 Valve control unit (alarm means)
72 Alarm judgment part (alarm means)
80 Alarm device (alarm means)

Claims (5)

A vehicle body that can travel,
A lifting device provided in the vehicle body;
A workbench attached to the lifting device and moved up and down;
An operating means provided on the workbench for operating the lifting device;
In an aerial work vehicle including an operation control unit that controls the operation of the lifting device based on an operation signal from the operation unit,
A light projecting unit that is provided at one end of the work table and irradiates light in a direction substantially parallel to the floor surface at a predetermined height position from the floor surface of the work table;
A light receiving means provided at the other end of the workbench and capable of receiving the light emitted from the light projecting means;
And a warning unit that performs a warning operation when the amount of the light received by the light receiving unit becomes a predetermined level or less when the light is irradiated from the light projecting unit. Aerial work vehicle. The work table is configured to be able to expand and contract the floor area in a predetermined direction,
2. The work at a high place according to claim 1, wherein the light projecting means is provided on one end side in the enlargement / reduction direction of the work table, and the light receiving means is provided on the other end side in the enlargement / reduction direction. car. The light projecting means is configured to be capable of adjusting a height position of the light to be irradiated from the floor surface,
The aerial work vehicle according to claim 1 or 2, wherein the light receiving means is configured to be capable of adjusting a height position of the portion that receives the light from the floor surface. The operation means includes an operation lever operated by an operator's hand and a foot switch operated by a foot, and an operation signal from the operation lever is transmitted only when the foot switch is turned on. Configured to transmit to the actuation control means;
The aerial work vehicle according to any one of claims 1 to 3, wherein the light projecting unit is controlled to emit the light only when the foot switch is turned on. .   The aerial work vehicle according to any one of claims 1 to 4, wherein the light projecting unit is controlled to emit the light when a traveling work state of the vehicle is detected.

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