JP2011256034A - Device and method for detecting height of crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a height detecting device of a crane, which can accurately measure a crane position including the vertical direction thereof with a simple construction and in which it is not necessary to lay an electric wire and the like for the height detecting device in a truck being a movable part, and a height detecting method of the crane.SOLUTION: A wire type encoder 40 disposed on a crane body 12 has an encoder body 42 and a measurement wire 44 which can be pulled out from the encoder body 42 by a prescribed length. The measurement wire 44 pulled out from the encoder body 42 is extended in parallel with the movement direction of the truck 14, turned in a vertical direction by a pulley 46 provided to the truck 14 and attached to a crane hook 18 suspended on the lower part of the truck 14.

Description

  The present invention relates to a detection device and a detection method for detecting the height of an engaging means such as a crane hook that engages an object to be conveyed by a crane.

  Cranes such as overhead cranes used indoors such as warehouses can move along the X direction extending substantially horizontally, the Y direction extending substantially horizontally and substantially perpendicular to the X direction, and the Z direction extending substantially vertically. It has a simple structure, and is used to engage or lift an object to be transported to a predetermined position by engaging an engagement means such as a crane hook with the object to be transported arranged in a warehouse. Here, in order to move the engagement means to a position where the engagement means can be engaged with the conveyance target, it is necessary to first know the spatial position of the engagement means. In order to know the spatial position, it is necessary to measure the position in each of the X, Y, and Z directions, and various measuring means or measuring methods have been proposed.

  For example, Patent Document 1 discloses a tracking method and apparatus in which a laser rangefinder is mounted on each of a crane and a lateral traveling carriage that runs on the crane, and the position of the crane is detected using the laser rangefinder. .

  Patent Document 2 discloses a technique for detecting a traveling position of a saddle unit of a crane, a traversing position of a hoist, and an ascending / descending position of a lifting tool with a rotary encoder.

JP-A-5-270617 JP 10-330073 A

  In the invention described in Patent Document 1, it is described that the position of the crane hand (Z direction) is measured by the laser rangefinder in addition to the position of the crane (X direction) and the position of the carriage on the crane (Y direction). Yes. However, the crane hand is likely to swing due to its vertical movement or the like, and an appropriate measurement may be difficult with a configuration using a laser beam and a reflector. Further, since the laser beam emitting portion is provided on the carriage, it is necessary to lay cables for that purpose on the carriage. When laying cables on the movable part, a complicated structure is required.

  On the other hand, when a rotary encoder is used as in Patent Document 2, the rotary encoder is usually attached to a rotating shaft of a drum or a rotating shaft of a motor that drives the drum. However, since the winding wire that supports the hanger tends to change (elongate) in size over time, it is necessary to periodically correct the wire for the encoder. Moreover, the operation | work which attaches an encoder to the rotating shaft of a drum or a motor involves complicated work, such as alignment.

  Therefore, the present invention can accurately measure the crane position including the vertical direction (Z direction) with a simple configuration, and does not need to lay electric wiring or the like for the height detection device on the cart that is a movable part. An object of the present invention is to provide a height detection device and a detection method.

  In order to achieve the above object, the invention according to claim 1 is a crane main body, a carriage configured to be movable on the crane main body, and suspended from the carriage so as to be able to engage with an object to be conveyed. A height detecting device for detecting the height of the engaging means in a crane device comprising: a wire encoder having an encoder body fixedly disposed on the crane body; A bogie position measuring means for measuring the position of the bogie on the crane body, and the measuring wire provided in the bogie and drawn from the encoder body toward the bogie extends in a vertically downward direction. There is provided a height detecting device comprising a turning means, wherein the measuring wire turned by the turning means is connected to the engaging means.

  The invention according to claim 2 is a crane main body, a carriage configured to be movable on the crane main body, an engagement means suspended from the carriage and configured to be able to engage with an object to be conveyed; A height detecting method for detecting the height of the engaging means in a crane apparatus comprising: a wire type encoder body fixed to the crane body, and a measuring wire from the encoder body toward the carriage The measuring wire is deflected so as to extend vertically downward by the deflecting means provided on the carriage, and the measuring wire is connected to the engaging means, and the encoder body passes through the deflecting means. Then, the length of the measurement wire drawn up to the engaging means is detected, the position of the carriage on the crane body is measured by the carriage position measuring means, and the measurement is performed. A height detection method for detecting the height of the engaging means from the length of the ear withdrawal, the position of the carriage on the crane body, and the positional relationship of the encoder body, the carriage and the turning means. provide.

  According to the present invention, since the wire encoder is used for detecting the height position of the engaging means, the measurement does not affect even if the engaging means swings, and the main body of the wire encoder is the crane main body. Therefore, it is not necessary to provide electric wiring or the like for the wire encoder on the cart that is a movable part. Further, since tension is not substantially applied to the wire of the wire encoder, it is not necessary to perform elongation correction or the like when the rotary encoder is used.

It is a figure which shows schematic structure of the overhead crane provided with the winding height detection apparatus which concerns on suitable embodiment of this invention. It is the side view which looked at the overhead crane of FIG. 1 in the X direction. It is a figure which shows an example of the communication form in connection with the onboard terminal which each overhead crane has.

  FIG. 1 is a diagram illustrating a schematic configuration of an overhead crane including a winding height detection device according to a preferred embodiment of the present invention. The overhead crane 10 has a crane main body 12 configured to be movable in a substantially horizontal first direction (X direction in FIG. 1), and a second direction different from the X direction (substantially in the illustrated example). The carriage 14 is configured to be movable in the horizontal direction (Y direction orthogonal to the X direction), and the engagement means 18 is provided on the carriage 14 so as to be able to engage with the conveyance object 16. In FIG. 1, the object 16 to be conveyed is shown as a steel plate coil placed on the floor 20 of the warehouse, and the engaging means 18 can be engaged with the center hole of the steel plate coil to lift the steel plate coil. Although these are shown as a substantially U-shaped crane hook, these are merely examples, and the shapes of the object to be transported and the crane hook are not limited thereto.

  The crane main body 12 in FIG. 1 is provided at a predetermined height on a side wall surface (not shown) of a warehouse or the like and can travel on a first rail 22 extending in the X direction by a driving means (not shown). The X-direction position (traveling position) is measured by a crane position measuring means. A specific example of the crane position measuring means is provided on a plurality of labels or tags 24 arranged in a line at equal intervals in parallel to the first rail 22 and the Y direction end of the crane body 12 so as to read the tags 24. And an antenna 26 configured as described above. Depending on which of the plurality of tags 24 is detected by the antenna 26, the position of the crane body 12 in the X direction can be obtained. As the tag 24, for example, an IC tag such as an RFID or a bar coat tag printed with a barcode can be used. Further, instead of the method of reading the tag, a rotary encoder (not shown) may be provided on the wheel 28 of the crane main body traveling on the first rail 22 or the rotation shaft of the motor that rotationally drives the wheel 28. Or the X direction position of the crane main body 12 can also be measured using a laser type distance meter.

  In the illustrated example, two overhead cranes are described, but there may be one overhead crane or three or more overhead cranes. However, when there are multiple overhead cranes, if a laser distance meter is used to measure the position of each overhead crane in the X direction, the crane body of one overhead crane is used to measure the distance of the crane body of another overhead crane. May be difficult to apply. Therefore, when there are a plurality of overhead cranes, it is preferable to use a tag type or a bar code type as shown in FIG.

  The carriage 14 in FIG. 1 is provided on the crane main body 12 and can travel on a second rail 30 extending in the Y direction by a driving means (not shown). The position (transverse position) of the carriage 14 in the Y direction is the carriage. It is measured by the position measuring means. A specific example of the cart position measuring means is a laser distance meter. More specifically, the laser beam emitting unit 32 provided at the end of the crane body 12 in the Y direction and the laser beam emitting unit 32 attached to the cart 14 are used. And a reflecting plate 34 that reflects the laser beam from. In addition, a wire encoder described later may be used instead of the laser distance meter.

  The crane hook 18 in FIG. 1 is suspended from the carriage 14 and configured to be vertically movable (Z direction). Specifically, the crane hook 18 is suspended by being connected to a winding wire 38 wound around a wire drum 36 that is configured to be rotatable by a driving means (not shown). Accordingly, the position of the crane hook 18 in the Z direction is determined by the rotational angle position of the wire drum 36. In the illustrated example, the crane hook 18 is suspended by one wire 38, but a plurality of wires 38 may be provided, and a plurality of wire drums may be provided. The number of wires and wire drums can be selected as appropriate according to the shape and weight of the object to be conveyed, the form of the crane hook and crane hand, and the like.

  In order to move the crane hook 18 to a desired spatial position, the current position of each of the X-direction position of the crane body 12, the Y-direction position of the carriage 14 and the Z-direction position of the crane hook 18 is measured to obtain the desired spatial position. It is necessary to move to the coordinates corresponding to. Here, since the positioning in the X and Y directions can be performed by the same method as the conventional one using the above-described configuration, a detection device and a detection method for obtaining the position of the crane hook 18 in the Z direction will be described below.

  FIG. 2 is a side view of the overhead crane in FIG. 1 as viewed in the X direction. As shown in FIGS. 1 and 2, the encoder main body 42 of the wire encoder 40 is fixedly arranged at a position on the crane main body 12 that does not interfere with the carriage 14 (for example, an end portion in the Y direction of the crane main body 12). The encoder body 42 is connected to electrical wiring or the like (not shown) for supplying power to the wire encoder. The wire encoder 40 includes an encoder body 42 and a measurement wire 44 that can be pulled out from the encoder body 42 by a predetermined length, and is configured to detect the length of the measurement wire 44 drawn from the encoder body 42. Yes. Typically, the encoder body 42 is connected to a housing containing a wire drum (not shown) around which the measurement wire 44 can be wound, and a rotation shaft of the wire drum. A rotary encoder (not shown) for detecting the position is included, but the configuration of the wire encoder itself may be well-known, and detailed description thereof is omitted.

  In the present embodiment, the measurement wire 44 drawn out from the encoder main body 42 extends in parallel with the movement direction (Y direction) of the carriage 14 and engages with a turning means (a pulley in the illustrated example) 46 provided on the carriage 14. At the same time, it is turned substantially vertically downward by the turning means, and the tip of the measuring wire 44 is connected to the crane hook 18 suspended below the carriage 14.

By providing the measurement wire 44 of the wire encoder 40 as shown in FIG. 2, the pull-out length L of the measurement wire 44 detected by the wire encoder 40 is equal to the Y-direction distance D from the encoder body 42 to the pulley 46, This is the sum of the Z-direction distance H from the pulley 46 to the crane hook 18. The Y-direction distance D is equal to the sum of the Y-direction distance D1 between the laser beam emitting portion 32 and the reflection plate 34 and the Y-direction distance D2 between the reflection plate 34 and the pulley 46. Here, since D1 can be obtained by laser distance measurement and D2 is known, the winding height (Z direction position) H of the crane hook to be obtained can be easily obtained from the following equation.
H = LD-L- (D1 + D2)

  In the form of FIG. 2, the Y-direction positions of the laser beam emitting unit 32 and the encoder main body 42 are matched, but there are cases where both are arranged so that the Y-direction positions of both do not match. However, in that case, the above equation may be corrected by obtaining the difference between the positions in the Y direction in advance.

  The means for measuring the Y-direction distance D1 is not limited to the laser type distance meter including the laser beam emitting part 32 and the reflecting plate 34. For example, even if the Y-direction position of the carriage 14 is obtained using another wire type encoder. Good. When the other wire type encoder is used, it is preferable that the encoder main body is fixedly disposed on the crane main body 12 and the measurement wire drawn from the encoder main body is connected to an appropriate portion of the carriage 14. Further, as the turning means of the measuring wire 44, one that does not cause a large stress or scratch resistance on the measuring wire 44 is preferable. For example, instead of the above-described pulley 46, a substantially circular shape that can be driven and rotated according to the operation of the measuring wire 44. A cross-section rod or the like can also be used.

  The distance in the Z direction between the carriage 14 and the crane hook 18 is measured using a laser distance meter. Specifically, the carriage 14 is provided with a laser beam emitting portion, and the crane hook 18 is provided with a reflector. Distance measurement is also possible. However, since the crane hook is easily swung by various operations such as its vertical movement, the laser light from the laser light emitting part is not appropriately reflected by the reflector, and there is a possibility that the distance cannot be measured. Furthermore, it is necessary to provide cables and wirings for laser emission on the carriage, which is a movable part, and the structure around the cables and wirings becomes complicated. On the other hand, the position of the crane hook 18 in the Z direction can be obtained from the output of the encoder by attaching a rotary encoder to the rotating shaft of the wire drum 36 that winds the winding wire 38 or the rotating shaft of the motor that drives the wire drum. It is. However, since the winding wire tends to change (elongate) in size over time, it is necessary to periodically correct the elongation of the wire. Moreover, the operation | work which attaches an encoder to the rotating shaft of a wire drum or a motor involves complicated operations, such as alignment. On the other hand, in the present invention, since a wire encoder is used for detecting the height position of the crane hook, the measurement does not affect even if the crane hook swings, and the wire encoder body is fixed to the crane body. Since it is arranged, it is not necessary to provide electric wiring or the like for the wire encoder on the carriage that is a movable part. Further, since tension is not substantially applied to the wire of the wire encoder, it is not necessary to perform elongation correction or the like when the rotary encoder is used. Therefore, according to the present invention, the height position of the crane hook can be accurately detected with a simple structure.

  FIG. 3 is a diagram illustrating an example of a control form of each overhead crane. As shown in FIG. 1, each overhead crane includes an onboard terminal 48, and an operator can input an instruction regarding a predetermined work from the onboard terminal 48. On the other hand, the onboard terminal 48 is connected to a sequencer (PLC) 50 electrically connected to the position measuring means in the X, Y, and Z directions described above. The sequencer 50 is connected to the crane hook from the position measuring means. 18 receives information on the X-direction position (traveling position), Y-direction position (transverse position), and Z-direction position (winding height), and the crane hook 18 performs a predetermined operation (based on an input instruction from the operator). Travel) of the crane body 12 on the first rail 22, travel drive means of the carriage 14 on the second rail 30, and winding of the winding wire 38 connected to the crane hook 18. An instruction is sent to the rotational drive motor of the means (wire drum 36).

  Information received by the sequencer 50 from the position measuring means, information on instructions from the sequencer 50 to each driving means, and the like can be transmitted wirelessly to the access point 52 via the on-board terminal 48. The access point 52 is connected to the server 56 via a dedicated LAN 54 or the like, and therefore the server 56 can centrally manage the operation status of each crane.

  Note that the wire encoder used in the present invention includes components such as a measurement wire, a wire drum that winds the measurement wire, and a rotary encoder that detects the rotational position of the wire drum, in addition to those available as an integrated product. It may be incorporated individually.

  In the above-described embodiment, the application target of the detection device and the detection method according to the present invention has been described as an overhead crane. However, the present invention can be similarly applied to a portal crane (gantry crane).

DESCRIPTION OF SYMBOLS 10 Overhead crane 12 Crane main body 14 Conveyance object 18 Crane hook 24 Tag 26 Antenna 32 Laser beam emitting part 34 Reflector plate 36 Wire drum 38 Winding wire 40 Wire type encoder 42 Encoder main body 44 Measuring wire 46 Pulley 48 On-machine terminal

Claims (2)

The engagement in a crane apparatus comprising: a crane body; a carriage configured to be movable on the crane body; and an engagement means suspended from the carriage and configured to be able to engage with an object to be conveyed. A height detecting device for detecting the height of the means,
A wire encoder having an encoder body fixedly disposed on the crane body;
A carriage position measuring means for measuring the position of the carriage on the crane body,
Turning means provided on the carriage and turning the measurement wire drawn from the encoder body toward the carriage so as to extend vertically downward;
The measuring wire diverted by the diverting means is connected to the engaging means;
Height detection device. The engagement in a crane apparatus comprising: a crane body; a carriage configured to be movable on the crane body; and an engagement means suspended from the carriage and configured to be able to engage with an object to be conveyed. A height detection method for detecting the height of the means,
The encoder body of the wire encoder is fixedly arranged on the crane body,
A measurement wire is drawn from the encoder body toward the carriage, and the measurement wire is deflected so as to extend vertically downward by a deflection means provided on the carriage, and the measurement wire is further connected to the engagement means. ,
Detecting the drawing length of the measurement wire from the encoder body to the engaging means via the turning means,
Measuring the position of the carriage on the crane body by means of a carriage position measuring means;
Height detection for detecting the height of the engagement means from the drawing length of the measurement wire, the position of the carriage on the crane body, and the positional relationship of the encoder body, the carriage and the turning means. Method.

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