JP2007045532A - Work attachment device and load detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect hanging load applied to an attachment of an arm tip part by an inexpensive configuration. <P>SOLUTION: This work attachment device and load detector are provided with a bracket member 10 swingably supported by the arm tip part; an attachment member 30 holding a work object 50 in the air; and a load detection member 20 sandwiched between the bracket member 10 and the attachment member 20 and detecting hanging load applied to the vertically downward direction by the work object 50. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a work attachment device and a load detector for detecting a suspension load of a work object held by a lifting magnet, a fork grapple or the like.

  As this type of load detection device, for example, the one described in Patent Document 1 is known. The device described in Patent Document 1 detects a suspension load of a tilt attachment supported on a tip of an arm via a pin so as to be swingable. A pin type load cell is attached to a pin coupling portion of the attachment, The load is detected by the output of the mold load cell.

Japanese Patent Application Laid-Open No. 2002-277311

  However, the pin type load cell is expensive and causes an increase in the price of the device. In addition, the use of a pin type load cell is problematic in terms of strength.

The work attachment device according to the present invention is sandwiched between a bracket member pivotally supported at the tip of an arm so as to be swingable, an attachment member for holding a work object in the air, and the bracket member and the attachment member. And a load detecting member that detects a suspended load acting downward in the vertical direction by the object.
The load detection member can be substantially ring-shaped.
You may make it attach the upper end part of the member for load detection to the lower end part of a bracket member, and attach a lower end part to the upper end part of an attachment member via an intermediate member.
The load detector according to the present invention includes a first member that is integrally attached to a bracket member that is pivotally supported at the tip of the arm and a second member that is integrally attached to an attachment member that holds the work object in the air. And a sensor unit that is disposed so as to be sandwiched between the first member and the second member, and that detects a suspension load that acts downward in the vertical direction by the work object via the second member; It is characterized by having.

  According to the present invention, since the load detection member is sandwiched between the bracket member and the attachment member at the arm tip portion, it is not necessary to detect the pin load acting on the pin coupling portion, and the structure is inexpensive. Suspension load can be detected.

Hereinafter, an embodiment of a working attachment device according to the present invention will be described with reference to FIGS.
FIG. 1 is an external side view of a lifting magnet machine to which the present invention is applied. This lifting magnet machine uses a hydraulic excavator as a base machine, and includes a traveling body 1, a revolving body 2 that is turnably supported on the traveling body 1, and a work front 3 that is rotatably attached to the revolving body 2. Have

  The work front 3 is pivotally supported by the swing body 2 so as to be pivotally supported, an arm 5 pivotally supported by the tip of the boom, and pivotally supported by the tip of the arm. And a work attachment device 100. The boom 4 moves up and down by the expansion and contraction of the boom cylinder 4a, and the arm 5 is clouded or dumped by the expansion and contraction of the arm cylinder 5a. The attachment device 100 is tilted by expansion and contraction of the cylinder 6a via the link mechanism (links 6b and 6c).

  FIG. 2 is an exploded perspective view of the attachment device 100, and FIG. As shown in FIG. 2, the attachment device 100 includes a bracket 10 connected to an arm tip, a ring-shaped scale 20 having a load detection mechanism, and a lifting magnet 30 as a work attachment. The ring-shaped scale 20 is sandwiched between the bracket 10 and the lifting magnet 30, and the lifting magnet 30 is supported from the bracket 10 via the ring-shaped scale 20.

  The bracket 10 has a shape in which a pair of plates 12 are erected on the upper surface of the disk 11, and through holes 12 a and 12 b are opened in each plate 12. The bracket 10 is connected to the arm 5 via a pin 7a (FIG. 1) inserted into the through hole 12a, and is connected to the link 6b via a pin 7b (FIG. 1) inserted into the through hole 12b. Yes. As a result, the bracket 10 can swing at the tip of the arm. A plurality of through holes 11a are opened in the disk 11 in the circumferential direction.

  As shown in FIGS. 2 and 3, the ring-shaped scale 20 includes an inner ring 21 located on the inner diameter side, an outer ring 22 located on the outer diameter side, and a sensor 23. The sensor 23 is mounted in a state of being sandwiched between the inner ring 21 and the outer ring 22 in the vertical direction. When a vertical compressive force is applied to the sensor 23 by both the rings 21 and 22, the sensor 23 is compressed. A signal corresponding to the force is output. A plurality of sensors 23 are provided at regular intervals in the circumferential direction, for example, three at every 120 ° in the circumferential direction.

  The upper end surface of the inner ring 21 protrudes above the upper end surface of the outer ring 22, and a screw hole 21 a is opened on the protruding upper end surface corresponding to the through hole 11 a of the disk 11. A bolt 41 penetrating the through hole 11a is screwed into the screw hole 21a, whereby the bracket 10 (disk 11) and the ring scale 20 (inner ring 21) are fastened together. A plurality of through holes 22 a are opened in the outer ring 22 in the circumferential direction.

  A ring-shaped flange portion 31 is provided on the upper surface of the lifting magnet 30, and a screw hole 31 a is opened in the flange portion 31 corresponding to the through hole 22 a of the outer ring 22. A bolt 42 penetrating the through hole 22a is screwed into the screw hole 31a, whereby the ring scale 20 (outer ring 22) and the lifting magnet 30 (flange portion 31) are fastened together. Other attachments can be attached to the ring-shaped scale 20.

  As shown in FIG. 3, a buffer member 43 is interposed inside the flange portion 31, that is, between the inner ring 21 below the sensor 23 and the lifting magnet 30. The impact member 43 is formed of resin or the like, and cushions an impact acting on the sensor 23 from the lifting magnet 30 during operation. In this case, the impact member 43 is formed to be thicker than the gap where the impact member 43 is disposed, and the impact member 43 is used in a contracted state, that is, in a state where a preload is applied to the impact member 43 in order to enhance the buffer function. preferable.

  FIG. 4 is a block diagram showing a control configuration of the work attachment device according to the present embodiment. Signals from the sensors 23 of the ring scale 20 are input to the controller 25, and a vertical downward load acting on the ring scale 20 is calculated based on these input signals. That is, the total force acting on the ring scale 20 is obtained by calculating the resultant force of the loads acting on each sensor 23.

  The memory of the controller 25 stores in advance a load that acts on the ring scale 20 in a state where nothing is attracted to the lifting magnet 30, that is, a load that acts only by the weight of the lifting magnet 31. The controller 25 subtracts the stored load from the total load, and calculates the weight of the adsorbate (50 in FIG. 1) adsorbed on the lifting magnet 30. This calculated value is output to the display monitor 26, and the weight of the adsorbent 50 is displayed on the display monitor 26.

  According to the above configuration, when the lifting magnet 30 attracts the attracted object 50 as the work object, the outer ring 22 of the ring-shaped scale 20 is pulled downward with respect to the inner ring 21 by the weight of the attracted object 50. A compressive force acts on the sensor 23. At this time, as the weight of the adsorbent 50 increases, the tensile force acting on the ring scale 20 (compressive force for the sensor 23) increases, and the sensor 23 outputs a signal corresponding to the weight of the adsorbent 50. Therefore, by processing the signal from the sensor 23 by the controller 25, the weight (suspension load) of the adsorbent 50 can be detected.

  When the suspension load is actually detected, the operator extends and retracts (tilts) the cylinder 6a to hold the attachment device 100 in a horizontal state as shown in FIG. At this time, since a vertical load acts on the sensor 23 in the vertical direction, the suspension load can be detected with high accuracy based on the output value of the sensor 23. When the attachment device 100 is not in a horizontal state, the suspension load can be calculated by correcting the output value of the sensor 23 according to the tilt angle. When a load detection command is input from the operator, the controller 25 automatically controls the attachment device 100 to be in a horizontal state, reads the output value of the sensor 23 at that time, and calculates the suspension load. Good.

According to the said embodiment, there can exist the following effects.
(1) The bracket 10 is pin-coupled to the tip of the arm, the lifting magnet 30 is attached with the ring scale 20 sandwiched below the bracket 10, and the suspension load (weight of the adsorbed material 50) acting on the lifting magnet 30 is applied. Detection was made with a ring-shaped scale 20. This eliminates the need to detect the load (pin load) acting on the pins 7a and 7b when detecting the load acting on the tiltable attachment that can be swung, so that a pin-type load cell is not required and the construction is inexpensive. it can. Further, the problem of strength when using a pin type load cell can be solved.

(2) Since the substantially ring-shaped ring-shaped scale 20 is sandwiched between the bracket 10 and the lifting magnet 30, sufficient strength of the attachment device 100 can be ensured.
(3) Since only the lifting magnet 30 is supported below the ring-shaped scale 20, the load detection value does not include the weight of other components, and the load detection accuracy is improved.
(4) Since the buffer member 43 is disposed between the ring-shaped scale 20 and the lifting magnet 30, the impact acting on the ring-shaped scale 20 from the lifting magnet 30 is mitigated, and the durability of the ring-shaped scale 20 is improved.

  In the above embodiment, the present invention is applied to the lifting magnet machine, but the present invention can be similarly applied to other construction machines in which the attachment device 100 is mounted on the arm tip. Therefore, the work object held in the air by the attachment is not limited to the attracted object 50 attracted by the lifting magnet 30.

  FIG. 5 is an example applied to a construction machine in which a fork grapple 35 is attached to the tip of the arm, and a ring-shaped scale 20 is sandwiched between the bracket 10 and the fork grapple 35. In this case, the bolt 42 (FIG. 3) is loosened, the lifting magnet 30 is removed, and the fork grapple 35 is attached to the ring-shaped scale 20. Since the fork grapple 35 can rotate in the direction of the arrow in FIG. 5, the attachment attachment portion (flange portion) at the upper end has a circular shape like the lifting magnet, and the ring-shaped scale 20 can be used as it is.

  In addition, when the shape of the attachment mounting part is different from the ring-shaped scale 20, a bracket corresponding to the shape of the attachment may be interposed as an intermediate member between the ring-shaped scale 20 and the attachment. Thereby, attachments of various shapes can be easily attached below the ring-shaped scale 20 without changing the shape of the ring-shaped scale 20.

  In the above embodiment, the substantially ring-shaped ring-shaped scale 20 is sandwiched between the bracket 10 (bracket member) and the lifting magnet 30 (work attachment member), but the load detection member is not ring-shaped but circular. Or it is good also as a rectangular shape. Further, the load detecting member may be divided in the circumferential direction instead of being integrally provided over the entire circumference. In this case, it is only necessary to provide a load detection member at least at a location where the sensor 23 is required (3 locations in the circumferential direction in the embodiment). Although a compressive force is applied to the sensor 23, a tensile force may be applied.

  The shape of the bracket 10 as the bracket member is not limited to that described above as long as the bracket 10 is swingably attached to the tip of the arm via a pin. Although the buffer member 43 is provided as an intermediate member between the ring-shaped scale 20 and the lifting magnet 30, the mounting position of the buffer member 43 may not be here. A ring-shaped scale 20 as a load detector is constituted by an inner ring 21 (first member), an outer ring 22 (second member), and a sensor 23 (sensor unit). The configuration of the load detector is not limited to this, and the sensor unit is disposed between the first member integrally attached to the bracket 10 and the second member integrally attached to the attachment 30, and the second member is arranged. Any device may be used as long as it can detect a vertically downward load acting via the. That is, as long as the features and functions of the present invention can be realized, the present invention is not limited to the work attachment device according to the embodiment. The above description is merely an example, and when interpreting the invention, there is no limitation or restriction on the correspondence between the items described in the embodiment and the items described in the claims.

1 is an external side view of a lifting magnet machine to which the present invention is applied. 1 is an exploded perspective view of a working attachment device according to an embodiment of the present invention. The principal part perspective view of the attachment apparatus for work which concerns on embodiment of this invention. The block diagram which shows the control structure of the work attachment apparatus which concerns on embodiment of this invention. The figure which shows the modification of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bracket 20 Ring-shaped scale 21 Inner ring 22 Outer ring 23 Sensor 30 Lifting magnet 35 Fork grapple 100 Attachment device for work

Claims (4)

A bracket member pivotally supported on the arm tip,
An attachment member for holding the work object in the air;
A work attachment device comprising: a load detection member that detects a suspension load that is sandwiched between the bracket member and the attachment member and acts downward in the vertical direction by the work object. The work attachment device according to claim 1,
The work attachment device, wherein the load detection member has a substantially ring shape. The work attachment device according to claim 1 or 2,
The load attachment member has an upper end attached to the lower end of the bracket member, and a lower end attached to the upper end of the attachment member via an intermediate member. A first member that is integrally attached to a bracket member that is pivotally supported at the tip of the arm;
A second member attached integrally to an attachment member for holding the work object in the air;
A sensor unit that is disposed between the first member and the second member so as to be vertically sandwiched between the first member and the second member, and detects a suspension load that acts downward in the vertical direction by the work object via the second member; A load detector comprising:

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