Working device

Abstract

To provide a work device allowing changeover operation at a pivotal connection position of a first link member of a link mechanism and a hydraulic cylinder to be easily carried out.SOLUTION: A tilt bucket 70 is pivotally connected to a tip part of an arm 34 so as to freely swing vertically as well as vertically swung through a link mechanism 80 by a bucket cylinder 39. A first link member 81 of the link mechanism 80 comprises a plurality of pivotal connection parts capable of being pivotally connected to the tip part of the bucket cylinder 39. The pivotal connection parts are placed so as to be aligned on the same circular arc a center of which is a pivotal connection axis line of an arm 34 of a base end of the bucket cylinder 39 in a state the first link member 81 is positioned in a reference posture for the arm 34.SELECTED DRAWING: Figure 24

Description

Technical Field

[0001] The present invention relates to a working device having an arm to which a working attachment can be attached.

Background Art

[0002] Conventionally, working vehicles such as a wheel loader and a hydraulic excavator (also referred to as an excavator, a backhoe, etc.) used when excavating the ground or moving excavated earth and sand are widely known. Such a working vehicle includes a working device having an arm provided on a vehicle body configured to be able to travel so as to be able to swing up and down, and various working attachments such as a bucket, a chip breaker (simply also referred to as a "breaker"), and an auger device are detachably configured at the tip of the arm. And by attaching and detaching and exchanging the attachment according to the working purpose, a predetermined work can be efficiently performed.

[0003] In such a working device, an attachment (for example, a bucket) swingably attached to the tip of the arm is known to be swingably moved up and down by a hydraulic cylinder via a link mechanism (for example, refer to Patent Document 1 below). The link mechanism is known to have a configuration including a first link member whose one end is pivotally connected to the arm so as to be able to swing up and down, and a second link member whose one end is pivotally connected to the attachment and the other end is pivotally connected to the first link member so as to be able to swing up and down. Further, the hydraulic cylinder is known to have a configuration in which its base end portion is pivotally connected to the arm so as to be able to swing up and down, and its tip portion is pivotally connected to the link mechanism on the pivot axis of the two link members.

[0004] In a working device, there are cases where it is desired to switch the operating performance of an attachment actuated by a hydraulic cylinder, for example, the swing range and excavation force of a bucket when the attachment is a bucket, according to the working conditions and the work content. Conventionally, a plurality of pivot joints that can be pivotally connected to the tip of the hydraulic cylinder are provided on the first link member, and the pivot position between the hydraulic cylinder and the first link member is selectively switched between these plurality of pivot joints to switch the operating performance of the bucket. A working device has been known (see, for example, Patent Document 2 below).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the working device as described above, the operation of switching the pivot position between the hydraulic cylinder and the first link member is generally performed as follows. First, the pivot connection between the tip of the hydraulic cylinder and the first link member at a certain pivot position (the pivot position before switching) is released. Next, in order to pivotally connect the tip of the hydraulic cylinder and the first link member at another pivot position (the pivot position after switching), alignment of the tip of the hydraulic cylinder with respect to the pivot position after switching is performed. This alignment is performed while expanding and contracting the hydraulic cylinder to adjust its length and swinging the hydraulic cylinder around the pivot axis between its base end and the arm. Then, with the alignment completed, the tip of the hydraulic cylinder and the first link member are pivotally connected.

[0007] Thus, in the working device, when switching the pivot position between the hydraulic cylinder and the first link member, it is necessary to align the tip of the hydraulic cylinder with the pivot position after switching. However, in the conventional working device, the alignment is between the tip of the hydraulic cylinder and the first link In a state where the pivotal connection with the member is released, the hydraulic cylinder is expanded and contracted to adjust its length. Therefore, there is a problem that the switching operation of the pivotal connection position is time-consuming.

[0008] The present invention has been made in view of such problems, and an object thereof is to provide a working device capable of easily performing a switching operation of a pivotal connection position between a first link member of a link mechanism and a hydraulic cylinder.

Means for Solving the Problems

[0009] In order to achieve the above object, the present invention includes an arm that can swing up and down, a working attachment (for example, the tilt bucket 70 in the embodiment) that can be attached to the arm so as to be swingable up and down, a first link member whose one end is pivotally connected to the arm so as to be swingable up and down, and in a state where the attachment is attached to the arm so as to be swingable up and down, a second link member whose one end is pivotally connected to the attachment and whose other end is pivotally connected to the first link member so as to be swingable up and down, and a base end portion is pivotally connected to the arm and a tip end portion is pivotally connected to the first link member so as to be swingable up and down, and an attachment hydraulic cylinder (for example, the bucket cylinder 39 in the embodiment) that expands and contracts to swing the attachment up and down with respect to the arm. The first link member is provided with a plurality of pivot portions (for example, the pin pivot holes 81d, 81e in the embodiment) to which the tip end portion of the attachment hydraulic cylinder can be pivotally connected, and a working device (for example, the excavator device 30 in the embodiment) capable of selectively switching and pivotally connecting the first link member and the attachment hydraulic cylinder among the plurality of pivot portions. Furthermore, in the working device according to the present invention, the attachment is attached to the arm so as to be swingable up and down, one end portion of the second link member is pivotally connected to the attachment and the other end portion is pivotally connected to the first link member so as to be swingable up and down, and in a state where the base end portion of the attachment hydraulic cylinder is pivotally connected to the arm and the tip end portion is pivotally connected to any one of the plurality of pivot portions of the first link member so as to be swingable up and down, the first link member can be swung up and down by the attachment hydraulic cylinder, and the first link member can be positioned in a predetermined reference posture with respect to the arm. In a state where the first link member is positioned in the reference posture with respect to the arm, the plurality of pivot portions are arranged so as to be aligned on the same arc centered on the pivot axis of the base end portion of the attachment hydraulic cylinder with respect to the arm.

[0010] In the above working device, it is preferable that the first link member is provided with an alignment portion for posture confirmation for visually recognizing whether or not the first link member is positioned in the reference posture with respect to the arm.

[0011] In the above-described working device, in a state where the first link member is positioned in the reference posture with respect to the arm, the pivot connection between the tip of the attachment hydraulic cylinder and one of the pivot connections is released, and the attachment hydraulic cylinder is swung around the pivot axis. When the tip of the attachment hydraulic cylinder faces in a state where it can be pivotally connected to another pivot connection, it preferably has a stopper member for pivot alignment that restricts the swing of the attachment hydraulic cylinder with respect to the first link member.

[0012] In the above-described working device, it is preferable that the stopper member is detachably attached to the first link member.

Effect of the Invention

[0013] In the working device according to the present invention as described above, in a state where the first link member is positioned in the reference posture with respect to the arm, a plurality of pivot connections of the first link member are arranged so as to be aligned on the same arc centered on the pivot axis of the base end portion of the attachment hydraulic cylinder with the arm. Therefore, in a state where the first link member is positioned in the reference posture with respect to the arm, by releasing the pivot connection between the tip of the attachment hydraulic cylinder and one pivot connection and swinging the attachment hydraulic cylinder around the pivot axis with the arm, it is possible to align the tip of the attachment hydraulic cylinder with another pivot connection without adjusting the length of the attachment hydraulic cylinder. Therefore, according to the working device according to the present invention, it is possible to easily perform the switching operation of the pivot position between the attachment hydraulic cylinder and the first link member. In the working device according to the present invention described above, by providing an alignment portion for posture confirmation for visually recognizing whether or not the first link member is positioned in the reference posture with respect to the arm on the first link member, it becomes possible to easily position the first link member in the reference posture with respect to the arm.

[0014] In the working device according to the present invention described above, by providing an alignment portion for posture confirmation for visually recognizing whether or not the first link member is positioned in the reference posture with respect to the arm on the first link member, it becomes possible to easily position the first link member in the reference posture with respect to the arm.

[0015] In the working device according to the present invention described above, when the first link member is positioned in a reference posture with respect to the arm, the pivot connection between the tip of the hydraulic cylinder for attachment and one pivot connection portion is released, and the hydraulic cylinder for attachment is swung around the pivot axis with the arm. When the tip of the hydraulic cylinder for attachment faces a state where it can be pivotally connected to another pivot connection portion, by having a stopper member for pivot alignment that restricts the swing of the hydraulic cylinder for attachment with respect to the first link member, it becomes possible to easily align the tip of the hydraulic cylinder for attachment with another pivot connection portion.

[0016] In the working device according to the present invention described above, since the stopper member can be detachably attached to the first link member, the stopper member is attached to the first link member only when performing the switching operation of the pivot position between the hydraulic cylinder for attachment and the first link member, and the stopper member can be removed from the first link member when the switching operation is not performed. Therefore, during work or the like, by removing the stopper member from the first link member, it is possible to prevent the swing range of the hydraulic cylinder for attachment from being restricted by the stopper member.

Brief Description of the Drawings

[0017]

Figure 1

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Figure 31

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, as an example of a working device according to the present invention, a shovel device 30 mounted on a wheeled hydraulic excavator (excavator) will be described. First, the overall configuration of the hydraulic excavator 1 will be described with reference to FIGS. 1 to 4.

[0019] As shown in FIGS. 1 to 4, the hydraulic excavator 1 includes a traveling body 10 configured to be able to travel, a revolving body 20 provided on the upper part of the traveling body 10 so as to be horizontally rotatable, and a shovel device 30 provided at the front part of the revolving body 20.

[0020] The traveling body 10 is configured to include double-tire type left and right front wheels 12, 12 serving as steering wheels and double-tire type left and right rear wheels 13, 13 serving as drive wheels on both left and right sides of the traveling body frame 11. At the lower part of the traveling body frame 11, a traveling motor (not shown) that rotationally drives the rear wheels 13, 13 via a power transmission mechanism such as a drive shaft 14 and a steering cylinder (not shown) that steers the front wheels 12, 12 are provided. The traveling body 10 can travel in an arbitrary direction and at an arbitrary speed by controlling the rotational operation of the traveling motor and the telescopic operation of the steering cylinder respectively. At the front part of the traveling body frame 11, a blade 16 is provided so as to be swingable up and down. The blade 16 is configured to be swingable up and down by expanding and contracting a blade cylinder 17 spanned between the blade 16 and the traveling body frame 11. At the rear part of the traveling body frame 11, left and right outriggers 18, 18 are provided so as to be swingable up and down. The outriggers 18, 18 are configured to be swingable up and down by expanding and contracting left and right outrigger cylinders 19, 19 spanned between the outriggers 18, 18 and the traveling body frame 11.

[0021] A slewing mechanism 3 is provided at the upper center of the traveling body frame 11. Although not shown in the figure, the slewing mechanism 3 has an inner ring fixed to the traveling body frame 11, an outer ring fixed to the slewing body 20, a slewing motor provided on the slewing body 20, and a rotary center joint for enabling the supply of hydraulic oil between the slewing body 20 and the traveling body 10. The slewing body 20 is provided on the traveling body frame 11 via the slewing mechanism 3 so as to be horizontally slewing freely, and is configured to be slewed left and right with respect to the traveling body 10 by rotating the slewing motor forward or backward.

[0022] The slewing body 20 has a slewing body frame 21 provided on the traveling body frame 11 via the slewing mechanism 3 so as to be horizontally slewing freely, and an operator cabin 25 provided on the slewing body frame 21. At the front part of the slewing body frame 21, a slewing body side bracket 22 protruding forward is provided. Further, on the slewing body 20, at the positions on the rear side and the right side of the operator cabin 25 A mounting chamber (not shown) is provided for mounting an engine (shown as "engine 61" in Fig. 5) and the like described later. A counterweight 27 having a curved surface shape and a mounting chamber cover 28 that can be opened and closed vertically are provided on the rear wall portion forming the mounting chamber.

[0023] The excavator device 30 includes a boom side bracket 31 provided on the swing body side bracket 22 so as to be swingable in the left - right direction about a vertical axis, a first boom 32 pivotally connected to the upper end portion of the boom side bracket 31 via a first pivot pin P1 so as to be vertically swingable (pitching motion), a second boom 33 pivotally connected to the tip end portion of the first boom 32 via a second pivot pin P2 so as to be vertically swingable (flexion - extension motion), and an arm 34 pivotally connected to the tip end portion of the second boom 33 via a third pivot pin P3 so as to be vertically swingable (flexion - extension motion). And a tilt bucket 70, which is an example of a work attachment, is mounted on the tip end portion of the arm 34 so as to be vertically swingable via a fourth pivot pin P4.

[0024] Furthermore, the excavator device 30 includes a swing cylinder 35 straddling between the swing body frame 21 and the boom side bracket 31, a first boom cylinder 36 straddling between the boom side bracket 31 and the first boom 32, a pair of left - right second boom cylinders 37, 37 straddling between the first boom 32 and the second boom 33, an arm cylinder 38 straddling between the second boom 33 and the arm 34, a bucket cylinder 39 whose base end portion (cylinder side end portion) is pivotally connected to the arm 34 so as to be vertically swingable via a fifth pivot pin P5, and a link mechanism 80 (details will be described later) provided so as to connect the arm 34, the tip end portion of the bucket cylinder 39, and the tilt bucket 70 in a state where the tilt bucket 70 is mounted on the tip end portion of the arm 34 so as to be vertically swingable.

[0025] The excavator side bracket 31 is configured to be swingable in the left - right direction with respect to the slewing body side bracket 22 (slewing body frame 21) by extending and retracting the swing cylinder 35. The first boom 32 is configured to be swingable vertically with respect to the excavator side bracket 31 by extending and retracting the first boom cylinder 36. The second boom 33 is configured to be swingable vertically with respect to the first boom 32 by extending and retracting the left and right second boom cylinders 37, 37. The arm 34 is configured to be swingable vertically with respect to the second boom 33 by extending and retracting the arm cylinder 38. The tilt bucket 70 is configured to be swingable vertically with respect to the arm 34 via the link mechanism 80 by extending and retracting the bucket cylinder 39.

[0026] The tilt bucket 70 includes a bucket body 71, a bucket bracket 72 that holds the bucket body 71 so as to be swingable in the left - right direction, and a tilt hydraulic actuator 73 provided between the bucket body 71 and the bucket bracket 72 for swinging the bucket body 71 in the left - right direction with respect to the bucket bracket 72. At the tip of the arm 34 and the link mechanism 80, instead of the tilt bucket 70, various attachments such as a normal bucket, a breaker, a crusher, a cutter, an auger device, etc. can be attached so as to be swingable vertically. When these attachments are installed, a plurality of connection ports (not shown) to which a hydraulic hose for supplying hydraulic oil to the hydraulic actuator (including the tilt hydraulic actuator 73) constituting the attachment can be connected are arranged at the tip of the upper surface of the arm 34.

[0027] The operator's cab 25 is formed in a substantially rectangular box shape to form an operation room where an operator can board, and a cabin door 26 that can be opened and closed horizontally is provided on the left side. Although not shown in the figure, the operator's cab 25 is provided with an operator seat on which the operator can sit facing the front side, a traveling operation device for performing the traveling operation of the traveling body 10 (rotation operation of the rear wheels 13, 13), a steering device for performing the steering operation of the traveling body 10 (steering of the front wheels 12, 12), an operation for the operation of the blade 16, the operation of the outriggers 18, 18, the turning operation of the revolving body 20, and the operation of the shovel device 30 (shown as "working operation device 41" in Fig. 5), a display device for displaying various vehicle information in the hydraulic excavator 1, and various operation switches and the like.

[0028] The traveling operation device includes a traveling operation member (for example, an operation pedal or an operation lever for rotating the rear wheels 13, 13) that is operated by an operator to perform the traveling operation of the traveling body 10. The steering device includes a steering member (for example, a steering wheel) that is operated by an operator to steer the front wheels 12, 12. The working operation device includes a working operation member (for example, an operation lever for operating the blade 16, an operation lever for operating the left and right outriggers 18, 18, an operation lever for turning the revolving body 20, and an operation lever for operating the shovel device 30) that is operated by an operator to perform the operation of the blade 16, the operation of the left and right outriggers 18, 18, the turning operation of the revolving body 20, and the operation of the shovel device 30.

[0029] Next, with reference to FIG. 5, a hydraulic control system (referred to as a "hydraulic control system for an excavator") for operating the excavator device 30 will be described. FIG. 5 schematically shows the configurations related to the hydraulic control of the swing cylinder 35, first boom cylinder 36, second boom cylinders 37, 37, arm cylinder 38, and bucket cylinder 39 among the hydraulic actuators in the hydraulic excavator 1, which are related to the excavator device 30. For convenience of explanation, these hydraulic actuators in the excavator device 30 are also referred to as hydraulic actuators for an excavator.

[0030] As shown in FIG. 5, the hydraulic control system for an excavator includes an engine 61, a working hydraulic pump 62 and a pilot hydraulic pump 63 driven by the engine 61, a working oil tank 64 for storing working oil, and a control valve unit 65 for controlling the supply direction and supply amount of the working oil discharged from the working hydraulic pump 62 and supplied to each hydraulic actuator for an excavator. The hydraulic control system for an excavator also includes a working operation device 41 and a controller 50.

[0031] The control valve unit 65 has control valves corresponding to the swing cylinder 35, first boom cylinder 36, second boom cylinders 37, 37, arm cylinder 38, and bucket cylinder 39, respectively. Among these control valves, the control valves corresponding to the first boom cylinder 36, arm cylinder 38, and bucket cylinder 39, respectively, are pilot operation switching valves whose spool movement is operated by pilot oil supplied from the pilot hydraulic pump 63 via the working operation device 41. On the other hand, the control valves corresponding to the swing cylinder 35 and the second boom cylinders 37, 37, respectively, are electromagnetic pilot switching valves composed of a pilot valve that is electromagnetically operated by an operation signal from the controller 50 and a main valve whose spool movement is operated by pilot oil supplied from the pilot hydraulic pump 63 via the working operation device 41 and the pilot valve.

[0032] The work operation device 41 supplies the pilot oil supplied from the pilot hydraulic pump 63 to the corresponding control valve in the control valve unit 65 according to the operation amount of the work operation member (operation lever for operating the excavator device 30). Further, when the swing cylinder 35 or the second boom cylinders 37, 37 are operated, the work operation device 41 outputs an electric signal corresponding to the operation amount of the work operation member to the controller 50. The controller 50 outputs an operation control signal to the corresponding control valve (pilot valve) in the control valve unit 65 according to the input signal from the work operation device 41, and controls the movement of the pilot valve.

[0033] In this way, in the hydraulic control system for excavators, the pilot oil supplied to the control valve unit 65 according to the operation state of the work operation member of the work operation device 41, or the pilot oil and the operation control signal output from the controller 50 control the corresponding control valve in the control valve unit 65 to operate. Then, by the operation control of this control valve, the direction and flow rate of the working oil supplied from the work hydraulic pump 62 to each excavator hydraulic actuator via the control valve unit 65 are controlled, and the corresponding excavator hydraulic actuator expands and contracts, whereby the excavator device 30 operates.

[0034] Next, with reference to FIGS. 6 to 18 additionally, the detailed configuration of the link mechanism 80 will be described. As shown in FIGS. 6 to 8, the link mechanism 80 includes a pair of left and right left first link members 81A and right first link members 81B, and a second link member 82. Hereinafter, the configurations of these link members 81A, 81B, and 82 will be described. Prior thereto, the configuration of the bucket cylinder 39 will be briefly described. The left first link member 81A and the right first link member 81B are collectively referred to as the first link member 81 (see FIGS. 6 and 7).

[0035] As shown in FIGS. 6 and 7, the bucket cylinder 39 is configured to have a cylinder tube 39a and a piston rod 39b. As shown in FIG. 18, a cylindrical pin receiving portion 39c is provided at the base end portion of the cylinder tube 39a, and is pivotally connected to the arm 34 so as to be swingable up and down by a fifth pivot pin P5 (see FIGS. 6 and 7) inserted into a pin pivot hole 39d of the pin receiving portion 39c. As shown in FIG. 18, a cylindrical pin receiving portion 39e is provided at the tip end portion of the piston rod 39b, and is pivotally connected to the first link member 81 (left first link member 81A and right first link member 81B) so as to be swingable up and down by a sixth pivot pin P6 (see FIGS. 6 to 8) inserted into a pin pivot hole 39f of the pin receiving portion 39e.

[0036] As shown in FIG. 17, the second link member 82 is configured to have a base plate 82a formed in a trapezoidal shape, a cylindrical pin receiving portion 82c provided at one end portion of the base plate 82a (the end portion closer to the bucket bracket 72), and a similarly cylindrical pin receiving portion 82e provided at the other end portion of the base plate 82a (the end portion closer to the first link member 81). One end portion of the second link member 82 is pivotally connected to the bucket bracket 72 so as to be swingable up and down by a seventh pivot pin P7 (see FIGS. 6 to 8) inserted into a pin pivot hole 82d of the pin receiving portion 82c. Further, the other end portion of the second link member 82 is pivotally connected to the left first link member 81A and the right first link member 81B so as to be swingable up and down by an eighth pivot pin P8 (see FIGS. 6 to 8) inserted into a pin pivot hole 82f of the pin receiving portion 82e.

[0037] The left first link member 81A and the right first link member 81B have a configuration that is substantially mirror-symmetrical to each other in the left-right direction, and the functions of each component are also substantially common. Therefore, the left first link member 81A and the right first link member 81B will be described centering on the left first link member 81A, and the right first link member 81B will be additionally described. In addition, components that are functionally common in the left first link member 81A and the right first link member 81B are assigned common reference numerals.

[0038] As shown in FIGS. 9 to 12, the left first link member 81A is mainly composed of a base plate 81a having a shape with a narrow width at one end side (base end side) and a wide width at the other end side (tip end side). At the base end portion of the base plate 81a, one pin pivot hole 81b penetrating in the left - right direction (the plate thickness direction of the base plate 81a) is formed, and at the tip end portion of the base plate 81a, three pin pivot holes 81c, 81d, 81e penetrating in the same left - right direction are formed. As shown in FIG. 8, the ninth pivot pin P9 is inserted into the pin pivot hole 81b, and the eighth pivot pin P8 is inserted into the pin pivot hole 81c. Also, either one of these is selected and the sixth pivot pin P6 is inserted into the pin pivot holes 81d, 81e. Note that the pin pivot holes 81d, 81e are arranged so as to satisfy a predetermined position condition. The details of this position condition will be described later. This position condition will be described in detail later.

[0039] As shown in FIG. 9, on the inner surface of the base plate 81a (the surface facing the left side surface of the arm 34), a pin guide portion 81f formed in a cylindrical shape along the edge of the pin pivot hole 81c and a pin guide portion 81g formed in a figure - of - eight shape in which two cylinders are connected along the edges of the pin pivot holes 81d, 81e are provided. On the outer surface of the base plate 81a (the surface opposite to the inner surface of the base plate 81a), as shown in FIG. 8, pin retaining portions 81h, 81i, 81j, 81k formed in a cylindrical shape along the respective edges of the pin pivot holes 81b, 81c, 81d, 81e are provided. And in each of the pin retaining portions 81h, 81i, 81j, 81k, a retaining pin hole 81m (see FIG. 11) for inserting a retaining pin (not shown) for preventing the pivot pin inserted into the pin pivot holes 81b, 81c, 81d, 81e from coming out is provided respectively.

[0040] As shown in FIG. 9, the left first link member 81A has two stopper insertion holes 81p and 81q penetrating in the left-right direction at the tip of the base plate 81a. These stopper insertion holes 81p and 81q are configured such that a stopper member 83 (see FIG. 8) is inserted when performing a pivot connection position switching operation described later. As shown in FIG. 8, the stopper member 83 is formed in a U shape as a whole by two stopper arm portions 83a and 83b extending parallel to each other and a connecting portion 83c connecting the base end portions of the stopper arm portions 83a and 83b. The stopper member 83 is used by inserting the stopper arm portions 83a and 83b into the stopper insertion holes 81p and 81q, respectively. Specifically, it is possible to insert the stopper arm portion 83a into the stopper insertion hole 81p and the stopper arm portion 83b into the stopper insertion hole 81q for use, or to insert the stopper arm portion 83a into the stopper insertion hole 81q and the stopper arm portion 83b into the stopper insertion hole 81p for use. Hereinafter, for convenience of explanation, it is assumed that the stopper arm portion 83a is inserted into the stopper insertion hole 81p and the stopper arm portion 83b is inserted into the stopper insertion hole 81q for use. Further, the stopper member 83 is used only when performing a pivot connection position switching operation described later, and is housed in a predetermined place such as inside the operator's cab 25 at other times.

[0041] As shown in FIGS. 10 and 12, the left first link member 81A has a straight line formed on one side edge portion on the base end side of the base plate 81a, and this straight line formed portion is configured as an alignment portion 81r for posture confirmation. This alignment portion 81r for posture confirmation is provided so that it is possible to visually recognize whether the left first link member 81A (first link member 81) is positioned in a reference posture with respect to the arm 34 when performing a pivot connection position switching operation described later. The reference posture refers to the posture of the first link member 81 with respect to the arm 34 when the alignment portion 81r for posture confirmation is parallel to the lower surface 34a (see FIG. 7) of the arm 34 in a state where the first link member 81 and the arm 34 are viewed from a direction (left-right direction) perpendicular to the outer surface of the base plate 81a.

[0042] As shown in FIGS. 13 to 16, the right first link member 81B has a configuration that is substantially mirror-symmetrical in the left-right direction with respect to the left first link member 81A. That is, the right first link member 81B is mainly composed of a base plate 81a that is mirror-symmetrical to the base plate 81a of the left first link member 81A. One pin pivot hole 81b is formed at the base end of the base plate 81a, and three pin pivot holes 81c, 81d, 81e and two stopper insertion holes 81p, 81q are formed at the tip of the base plate 81a. Further, as shown in FIG. 16, on the inner surface of the base plate 81a (the surface facing the right side surface of the arm 34), a cylindrical pin guide portion 81f formed along the edge of the pin pivot hole 81c and an 8-shaped pin guide portion 81g formed along the edges of the pin pivot holes 81d, 81e are provided. Furthermore, a linear alignment portion 81r for posture confirmation is provided at one side edge portion on the base end side of the base plate 81a of the right first link member 81B.

[0043] On the other hand, in the left first link member 81A, cylindrical pin fastening portions 81h, 81i, 81j, 81k (see FIG. 8) are provided on the outer surface of the base plate 81a, while in the right first link member 81B, such cylindrical pin fastening portions are not provided on the outer surface of the base plate 81a. This is the main difference in the configuration between the right first link member 81B and the left first link member 81A.

[0044] The first link member 81 (left first link member 81A and right first link member 81B) configured as described above has its base end pivotally connected to the arm 34 via the ninth pivot pin P9 so as to be swingable up and down. Specifically, as shown in FIG. 8, a pin pivot hole 34b penetrating in the left-right direction is formed in the arm 34. The ninth pivot pin P9 is inserted through the pin pivot hole 81b of the right first link member 81B disposed on the right side surface side of the arm 34, the pin pivot hole 34b of the arm 34, and the pin pivot hole 81b of the left first link member 81A disposed on the left side surface side of the arm 34 to pivotally connect the first link member 81 to the arm 34.

[0045] Further, the tip of the first link member 81 is pivotally connected to the second link member 82 via the eighth pivot pin P8 so as to be vertically swingable. Specifically, as shown in FIG. 8, the eighth pivot pin P8 is inserted through the pin pivot hole 81c of the right first link member 81B, the pin pivot hole 82f of the pin receiving portion 82e of the second link member 82, and the pin pivot hole 81c of the left first link member 81A to pivotally connect the first link member 81 and the second link member 82.

[0046] Furthermore, the tip of the first link member 81 is pivotally connected to the tip of the bucket cylinder 39 via the sixth pivot pin P6 so as to be vertically swingable. Specifically, as shown in FIG. 8, the sixth pivot pin P6 is inserted through the pin pivot hole 81d of the right first link member 81B, the pin pivot hole 39f of the pin receiving portion 39e at the tip of the bucket cylinder 39, and the pin pivot hole 81d of the left first link member 81A, enabling the first link member 81 to be pivotally connected to the tip of the bucket cylinder 39. On the other hand, the sixth pivot pin P6 is also inserted through the pin pivot hole 81e of the right first link member 81B, the pin pivot hole 39f of the pin receiving portion 39e at the tip of the bucket cylinder 39, and the pin pivot hole 81e of the left first link member 81A, enabling the first link member 81 to be pivotally connected to the tip of the bucket cylinder 39.

[0047] In this way, the link mechanism 80 can selectively switch the pivot position of the first link member 81 (the left first link member 81A and the right first link member 81B) pivotally connected to the tip of the bucket cylinder 39 between the position of the pin pivot hole 81d and the position of the pin pivot hole 81e of the first link member 81. Hereinafter, the pivot state of the link mechanism 80 when the first link member 81 is pivotally connected to the tip of the bucket cylinder 39 via the pin pivot hole 81d is referred to as the first pivot state, and the pivot state of the link mechanism 80 when the first link member 81 is pivotally connected to the tip of the bucket cylinder 39 via the pin pivot hole 81e is referred to as the second pivot state. Also, the switching of the pivot position between the first pivot state and the second pivot state is referred to as pivot position switching, and the operation of performing the pivot position switching is referred to as pivot position switching operation.

[0048] Here, with reference to FIGS. 19 and 20, an additional explanation will be given as to how the operating performance of the tilt bucket 70 in the shovel device 30 differs between the first pivot state and the second pivot state. FIG. 19 shows the swing range of the tilt bucket 70 around the fourth pivot pin P4 when the link mechanism 80 is in the first pivot state, and FIG. 20 shows the swing range of the tilt bucket 70 around the fourth pivot pin P4 when the link mechanism 80 is in the second pivot state.

[0049] When the bucket cylinder 39 expands and contracts while the link mechanism 80 is in the first pivot state, the output from the bucket cylinder 39 in its expansion and contraction operation is transmitted as torque around the fourth pivot pin P4 to the tilt bucket 70 via the first link member 81 and the second link member 82. The tilt bucket 70 swings vertically with respect to the arm 34 within the swing range shown in FIG. 19 around the fourth pivot pin P4.

[0050] Also, when the bucket cylinder 39 expands and contracts while the link mechanism 80 is in the second pivot state, the output from the bucket cylinder 39 in its expansion and contraction operation is similarly transmitted as torque around the fourth pivot pin P4 to the tilt bucket 70 via the first link member 81 and the second link member 82. The tilt bucket 70 swings vertically with respect to the arm 34 within the swing range shown in FIG. 20 around the fourth pivot pin P4.

[0051] In this way, in the excavator device 30, when the link mechanism 80 is in the first pivot state (when the tip of the bucket cylinder 39 is pivotally connected to the first link member 81 at the pin pivot hole 82d), the swing range of the tilt bucket 70 according to the telescopic operation of the bucket cylinder 39 is configured to be wider than when the link mechanism 80 is in the second pivot state (when the tip of the bucket cylinder 39 is pivotally connected to the first link member 81 at the pin pivot hole 82e). On the other hand, in the excavator device 30, when in the second pivot state, the torque transmitted to the tilt bucket 70 when extending the bucket cylinder 39 is increased compared to when in the first pivot state, and thereby the excavation force by the tilt bucket 70 is configured to be increased.

[0052] Next, with additional reference to FIGS. 21 to 31, a procedure example of the pivot position switching operation will be described. Hereinafter, the operation procedure when switching the pivot state of the link mechanism 80 from the first pivot state to the second pivot state will be described.

[0053] FIG. 21 shows an example state of the hydraulic excavator 1 (excavator device 30) when the link mechanism 80 is in the first pivot state. In this example, the revolving body 20 faces forward, and the traveling body 10 is shown in a state of stopping on a horizontal road surface GS. Also, in this example, the excavator device 30 as a whole faces forward, and the tilt bucket 70 is maintained in a state away from the road surface GS.

[0054] In the pivotal position switching operation of this example, from the state shown in Fig. 21, the bucket cylinder 39 is extended and retracted, and the first link member 81 of the link mechanism 80 is adjusted to be positioned in a reference posture with respect to the arm 34. That is, by the extension and retraction operation of the bucket cylinder 39, the first link member 81 is swung up and down with respect to the arm 34 around the ninth pivotal pin P9, and the posture of the first link member 81 with respect to the arm 34 is adjusted so that the alignment portion 81r for posture confirmation of the first link member 81 is parallel to the lower surface 34a of the arm 34 (see Fig. 22). Along with the posture adjustment of the first link member 81 at this time, the tilt bucket 70 swings up and down with respect to the arm 34 around the fourth pivotal pin P4. Note that this posture adjustment may be performed, for example, while an operator visually recognizes the state of the posture of the first link member 81 accompanying the extension and retraction operation of the bucket cylinder 39, or an operator other than the operator may visually recognize the state of the posture of the first link member 81 accompanying the extension and retraction operation of the bucket cylinder 39 and convey it to the operator while performing the operation.

[0055] Next, from the state shown in Fig. 22, while maintaining the posture of the first link member 81 with respect to the arm 34 (that is, without extending and retracting the bucket cylinder 39), the first boom cylinder 36, the second boom cylinders 37, 37, and the arm cylinder 38 are extended and retracted. Then, by this extension and retraction operation, the first boom 32, the second boom 33, and the arm 34 are swung up and down to move the tilt bucket 70 (bucket body 71) so that its bottom surface approaches the road surface GS in a state parallel to the road surface GS (see Fig. 23), and further, the bottom surface is brought into contact with the road surface GS (see Fig. 24). That is, by the extension and retraction operation of the first boom cylinder 36, the first boom 32 is swung up and down with respect to the shovel-side bracket 31 around the first pivotal pin P1, by the extension and retraction operation of the second boom cylinders 37, 37, the second boom 33 is swung up and down with respect to the first boom 32 around the second pivotal pin P2, and by the extension and retraction operation of the arm cylinder 38, the arm 3 The 4 is swung up and down with respect to the second boom 33 around the third pivot pin P3. Then, thereby, the tilt bucket 70 is moved so that the bottom surface of the tilt bucket 70 contacts the road surface GS in a state parallel to the road surface GS. By bringing the bottom surface of the tilt bucket 70 into contact with the road surface GS in this way, in the following procedure, even if the pivot connection between the bucket cylinder 39 and the first link member 81 is released, the tilt bucket 70 is supported by the road surface GS and thus does not swing up and down, so that the first link member 81 can be maintained in the reference posture.

[0056] Next, in the state shown in FIG. 24, a stopper member 83 is attached to the first link member 81 (see FIGS. 24 and 25). For the sake of convenience of explanation as described above, the stopper member 83 is attached to the first link member 81 by inserting the stopper arm portion 83a into the stopper insertion hole 81p (see FIG. 8) of the first link member 81 and inserting the stopper arm portion 83b into the stopper insertion hole 81q (see FIG. 8) of the first link member 81.

[0057] After the stopper member 83 is attached to the first link member 81, the sixth pivot pin P6 is removed from the pin pivot holes 81d of the first link member 81 (left first link member 81A and right first link member 81B) and the pin pivot hole 39f of the pin receiving portion 39e of the bucket cylinder 39 (see FIG. 8) (see FIG. 25). Thereby, the pivot connection between the first link member 81 and the tip of the bucket cylinder 39 is released. When the pivot connection between the first link member 81 and the bucket cylinder 39 is released, the bucket cylinder 39 becomes in a state where it can be swung up and down around the fifth pivot pin P5 (see FIG. 24) without being expanded and contracted.

[0058] After releasing the pivotal connection between the first link member 81 and the tip of the bucket cylinder 39, the bucket cylinder 39 is swung up and down around the fifth pivotal pin P5 (see Fig. 24), and the tip of the bucket cylinder 39 (pin receiving portion 39e) is brought into contact with the stopper arm portion 83a of the stopper member 83. Note that the up and down swinging of the bucket cylinder 39 at this time is manually performed by the operator. Also, at this time, the bucket cylinder 39 is not operated to expand and contract so that the length of the bucket cylinder 39 does not change.

[0059] As briefly described above, the pin pivotal connection holes 81d and 81e of the first link member 81 (left first link member 81A and right first link member 81B) are arranged so as to satisfy a predetermined position condition. The position condition is that, in a state where the bucket cylinder 39 is operated to expand and contract and the first link member 81 is positioned in a reference posture with respect to the arm 34, the pin pivotal connection hole 81d and the pin pivotal connection hole 81e are arranged on the same arc centered on the pivotal axis (central axis of the pin pivotal connection hole 39d) between the base end portion (pin receiving portion 39c) of the bucket cylinder 39 and the arm 34. Note that the radius dimension of this same arc is equal to the distance between the pivotal axes at both ends of the bucket cylinder 39 (the distance between the central axis of the pin pivotal connection hole 39d of the pin receiving portion 39c and the central axis of the pin pivotal connection hole 39f of the pin receiving portion 39e) in a state where the first link member 81 is positioned in a reference posture with respect to the arm 34.

[0060] Since the pin pivotal connection holes 81d and 81e of the first link member 81 are arranged on the same arc as described above, by swinging the bucket cylinder 39, which has had its pivotal connection with the first link member 81 released at the pin pivotal connection hole 81d as described above, up and down around the fifth pivotal pin P5, it is possible to align the position between the tip of the bucket cylinder 39 (pin pivotal connection hole 39f of the pin receiving portion 39e) and the pin pivotal connection hole 81e of the first link member 81 (such that the pin pivotal connection holes 39f and 81e face each other and their respective central axes coincide) without adjusting the length of the bucket cylinder 39.

[0061] Also, this alignment can be easily achieved by swinging the bucket cylinder 39 up and down around the fifth pivot pin P5 as described above, and bringing the pin receiving portion 39e of the bucket cylinder 39 into contact with the stopper arm portion 83a of the stopper member 83. Specifically, When the bucket cylinder 39 is swung up and down, the stopper arm portion 83a of the stopper member 83 is configured to come into contact with the pin receiving portion 39e to restrict the up and down swinging of the bucket cylinder 39 when the pin pivot hole 39f of the pin receiving portion 39e faces the pin pivot hole 81e of the first link member 81, that is, when the positions of both pin pivot holes 39f and 81e are aligned. Note that the other stopper arm portion 83b of the stopper member 83 is configured to come into contact with the piston rod 39b of the bucket cylinder 39 to restrict the up and down swinging of the bucket cylinder 39 when the pin pivot hole 39f of the pin receiving portion 39e faces the pin pivot hole 81d of the first link member 81, that is, when the positions of both pin pivot holes 39f and 81d are aligned.

[0062] After aligning the pin pivot hole 39f of the pin receiving portion 39e of the bucket cylinder 39 and the pin pivot hole 81e of the first link member 81 as described above, the sixth pivot pin P6 is inserted through the pin pivot hole 81e of the first link member 81 and the pin pivot hole 39f of the pin receiving portion 39e of the bucket cylinder 39 (see FIG. 27). Thereby, the first link member 81 and the tip end portion of the bucket cylinder 39 are pivotally connected via the pin pivot hole 81e of the first link member 81.

[0063] After the bucket cylinder 39 is pivotally connected to the first link member 81 via the pin pivot hole 81e by the sixth pivot pin P6, the stopper member 83 is removed from the first link member 81 (see FIGS. 28 to 30). Thereby, the pivot position switching operation when switching the pivot state of the link mechanism 80 from the first pivot state to the second pivot state is completed. The hydraulic excavator 1 after the switching is completed can operate the shovel device 30 to perform excavation work or the like with the tilt bucket 70 (see FIG. 31). As described above, the procedure example of the pivot position switching operation when switching the pivot state of the link mechanism 80 from the first pivot state to the second pivot state has been described. The pivot position switching operation when switching the pivot state of the link mechanism 80 from the second pivot state to the first pivot state can be performed in the same procedure as the above-described procedure, and thus the detailed description is omitted.

[0064] As described above, according to the shovel device 30, by maintaining the first link member 81 in a state of being positioned in a reference posture with respect to the arm 34, the pivot position adjustment (alignment) between the first link member 81 and the arm 34 when performing the pivot position switching operation of the link mechanism 80 can be easily performed manually. Therefore, it is possible to easily perform the pivot position switching operation in the link mechanism 80.

[0065] As described above, embodiments of the present invention have been explained. However, the scope of the present invention is not limited to the above embodiments. For example, in the above embodiments, a U-shaped stopper member 83 having two stopper arm portions 83a and 83b is used, but stopper members of other shapes may be used. For example, a stopper member formed in a single rod shape and having a rod-shaped portion (also referred to as a "base") that functions as a stopper may be used. Such a rod-shaped stopper member is used, for example, by inserting the base into the stopper insertion hole 81p of the first link member 81 when aligning the tip (pin pivot hole 39f) of the bucket cylinder 39 with the pin pivot hole 81e of the first link member 81. Further, when aligning the tip of the bucket cylinder 39 with the pin pivot hole 81d of the first link member 81, the base is inserted into the stopper insertion hole 81q of the first link member 81 and used. Note that the above-described U-shaped stopper member 83 and rod-shaped stopper member have a circular cross-section, but stopper members having other cross-sectional shapes such as an L-shaped cross-section may be used.

[0066] Also, in the above embodiments, the pivot positions between the bucket cylinder 39 and the first link member 81 are two positions, namely the position of the pin pivot hole 81d and the position of the pin pivot hole 81e. However, three or more selectable pivot positions may be provided. For example, a plurality of three or more pin pivot holes that can be selectively pivoted with the tip of the bucket cylinder 39 may be provided on the first link member 81 so as to be arranged on the same arc as described above.

[0067] Further, in the above-described embodiments, a tilt bucket 70 is used as an attachment that is mounted on the tip of the arm 34 so as to be swingable up and down. However, the present invention is not limited to this. As the attachment, a normal bucket, a breaker, a crusher, a cutter, an auger device, etc. may be used. In the above-described embodiments, the case where the present invention is applied to a working device (excavator device 30) of the hydraulic excavator 1 has been explained. However, the present invention can be similarly applied to a working device of other working vehicles other than hydraulic excavators, or to a working device other than the working device of a working vehicle, and the same effects can be obtained.

Explanation of Symbols

[0068] 1 Hydraulic excavator 10 Traveling body 20 Slewing body 30 Shovel device (working device) 34 Arm 39 Bucket cylinder (attachment) 39c, 39e Pin receiving part 39d, 39f Pin pivot hole 41 Working operation device 50 Controller 61 Engine 62 Working hydraulic pump 63 Pilot pump 65 Control valve unit 70 Tilt bucket 80 Link mechanism 81 First link member 81A Left first link member 81B Right first link member 81b, 81c, 81d, 81e Pin pivot hole 81p, 81q Stopper insertion hole 82 Second link member 83 Stopper member 83a, 83b Stopper arm part P3 Third pivot pin P4 Fourth pivot pin P5 Fifth pivot pin P6 Sixth pivot pin P7 Seventh pivot pin P8 Eighth pivot pin P9 Ninth pivot pin

Claims

1. An arm capable of swinging up and down, A working attachment that can be attached to the arm so as to be swingable up and down, A first link member having one end pivotally connected to the arm so as to be swingable up and down, In a state where the attachment is swingably attached to the arm, a second link member having one end pivotally connected to the attachment and the other end pivotally connected to the first link member so as to be swingable up and down respectively, An attachment hydraulic cylinder having a base end pivotally connected to the arm and a tip pivotally connected to the first link member so as to be swingable up and down respectively, and telescoping to swing the attachment up and down with respect to the arm, The first link member is provided with a plurality of pivot portions to which the tip of the attachment hydraulic cylinder can be pivotally connected, and the first link member and the attachment hydraulic cylinder can be selectively switched and pivotally connected between the plurality of pivot portions. A working device, In a state where the attachment is swingably attached to the arm, one end of the second link member is pivotally connected to the attachment and the other end is pivotally connected to the first link member so as to be swingable up and down respectively, and the base end of the attachment hydraulic cylinder is pivotally connected to the arm and the tip is pivotally connected to any one of the plurality of pivot portions of the first link member so as to be swingable up and down respectively, The first link member can be swung up and down by the attachment hydraulic cylinder, and the first link member can be positioned in a predetermined reference posture with respect to the arm, A working device, characterized in that in a state where the first link member is positioned in the reference posture with respect to the arm, the plurality of pivot portions are arranged so as to be aligned on the same arc centered on the pivot axis of the base end of the attachment hydraulic cylinder and the arm.

2. The working device according to claim 1, characterized in that the first link member is provided with an alignment portion for posture confirmation for visually checking whether the first link member is positioned in the reference posture with respect to the arm.

3. In a state where the first link member is positioned in the reference posture with respect to the arm, the pivot connection between the tip of the attachment hydraulic cylinder and one of the pivot connections is released, and the attachment hydraulic cylinder is swung around the pivot axis. When the tip of the attachment hydraulic cylinder faces a state where it can be pivotally connected to another pivot connection portion, there is a stopper member for pivot alignment that restricts the swing of the attachment hydraulic cylinder with respect to the first link member. The working device according to claim 1 or 2, characterized in that.

4. The working device according to claim 3, characterized in that the stopper member is detachably attached to the first link member.

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