JP4239185B2 - Excavator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic excavator capable of reducing its height during transportation.
[0002]
[Related background]
In this type of hydraulic excavator, generally, a rod side end portion of an arm cylinder and one end side of an arm, that is, an arm bracket are connected by a connecting pin. For example, in the case of the hydraulic excavator disclosed in Japanese Utility Model Publication No. 61-188650, the connecting pin is mounted in the elongated hole of the arm bracket and can be selectively positioned at one end position in the elongated hole.
[0003]
If the pin position of the connecting pin can be changed in this way, the maximum wrap angle of the arm with respect to the boom (the angle formed by the boom and the arm) can be made variable according to the pin position of the connecting pin. Therefore, even when using a long arm that is longer than the standard arm, for example, when transporting a hydraulic excavator, the pin position of the connecting pin is changed to a position where the maximum wrap-up angle of the arm is larger, so that The height of the boom, that is, the height of the hydraulic excavator can be reduced, and the height during transportation can be kept within the legal height limit.
[0004]
[Problems to be solved by the invention]
By the way, in the case of the hydraulic excavator described in the above publication, the connecting pin mounting slot is provided so as to be elongated in only one direction, so that the position of the connecting pin is moved by the expansion and contraction of the arm cylinder. In order to prevent this movement and hold the connecting pin at the end position of the long hole, a receiving plate is separately provided in addition to the original arm bracket. Also, when changing the pin position of the connecting pin, if the receiving plate is removed, the connecting pin will be in a free state in the slot, and the arm cylinder or arm may move inadvertently. It is not possible to secure the work to change the pin position.
[0005]
The present invention has been made based on the above-described circumstances, and an object of the present invention is to provide a hydraulic excavator that can change the pin position of a connecting pin safely and smoothly with a simple configuration.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the hydraulic excavator of the present invention (Claim 1) is provided with a bent pin receiving groove formed in the arm bracket, and the connecting pin can be movably received in the pin receiving groove. It has become. Pin receiving grooves are provided spaced apart in the expansion and contraction direction of the arm cylinder, it comprises two bent grooves connecting pin is selectively positioned, and a connecting portion groove portions connecting these bending grooves, each bent groove arm and two groove wall portions for clamping the ends of the connecting pins as viewed in the elongating and contracting direction of the cylinder is formed from the end wall defining a first end position or the second end position. The hydraulic excavator of the present invention is provided with a stopper plate provided detachably on the arm bracket, the groove wall portions, end wall and a stopper plate connecting pin define the first end position or the second end position A structure is provided in which the end portion is held in the bent groove portion at the first end position or the second end position in the pin receiving groove. In the case of the hydraulic excavator according to the present invention, the second end position is provided at a position where the maximum winding angle becomes larger than the maximum winding angle of the arm when the connecting pin is at the first end position.
[0007]
According to the hydraulic excavator described above, during normal work such as excavation, the connecting pin is held in the bent groove portion at the first end position in the pin receiving groove, and at this pin position, the driving force of the arm cylinder, that is, the connecting pin Is applied to the groove wall of the bent groove at the first end position. At this time, the maximum winding angle of the arm is determined by the pin position and the maximum extension length of the arm cylinder.
[0008]
On the other hand, when the excavator is transported, the connecting pin is moved and held in the pin receiving groove from the first end position to the bent groove portion at the second end position, and the load acting on the above-mentioned pin is also at the second end position. It is received by the groove wall portion in the bent groove portion . The maximum retracting angle of the arm when the connecting pin is at the second end position is larger than the maximum retracting angle at the first end position, and the height of the boom in the lying posture is lower.
[0009]
When moving the connecting pin from the first end position to the second end position, after removing the stopper plate from the arm bracket, in a direction substantially coincident with the groove direction of the bent groove portion at the first end position . This is done by applying a load of. In this case, since the connecting pin can move relatively freely in the groove direction of the bent groove portion , it can be moved by a small load. For example, the working pin consisting of a boom and an arm is set in a predetermined posture, and the connecting pin can be moved by combining the expansion and contraction operation of the arm cylinder and the boom hoisting operation with the arm restrained.
When the connecting pin is positioned in the bent groove portion at the first end position or the second end position, the stopper plate cooperates with the end wall of the bent groove portion defining the end position and the groove wall portion, and the connecting pin Holding the end of.
[0010]
Further, the groove width of the pin receiving groove is preferably narrower than the outer diameter of the connecting pin, and both end portions of the connecting pin fitted into the pin receiving groove are preferably rectangular. In this case, the groove wall portion at the first or second end position functions as a detent that restrains the rotation of the connecting pin. The step between the cylindrical portion of the connecting pin and the rectangular end portion also functions as a stopper that prevents the connecting pin from coming off from the pin receiving groove.
[0011]
Furthermore, it is preferable that the pin receiving groove further includes an insertion / removal position that allows the connection pin to be inserted / removed from the arm bracket. Specifically, the insertion / removal position can be obtained by partially widening the pin receiving groove. In this case, the connecting pin is mounted in the pin receiving groove at the insertion / removal position, and is moved to the desired first or second end position and positioned at the end position.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a hydraulic excavator 2 at the time of transportation, and the hydraulic excavator 2 is placed on a loading platform 4 such as a dedicated or general trailer and transported. At this time, the excavator 2 is in the transporting posture of the work machine 6, and the ground height H of the excavator 2 on the loading platform 4 (height of the work machine 6 from the ground) is within the legal height limit. .
[0013]
The work machine 6 includes a boom 8, and the lower end of the boom 8 is pivotally supported by a boom bracket (not shown) of the swivel base 10 of the excavator 2, and the swivel base 10 is expanded and contracted by a pair of boom cylinders 12 provided on the left and right. On the other hand, it can be rotated, that is, undulated.
An arm 16 is rotatably attached to the tip end side of the boom 8 via a pivot pin 14. The arm 16 and the boom 8 are connected to each other by an arm cylinder 18, and the arm cylinder 18 can rotate the arm 16 around the pivot pin 14 by expansion and contraction thereof.
[0014]
A bucket 24 as a working tool is attached to the distal end side of the arm 16 via a rotation pin 20 and a link mechanism 22, and the link mechanism 22 and the arm 16 are connected to each other by a bucket cylinder 26. Yes. The bucket cylinder 26 can rotate the bucket 24 around the rotation pin 20 via the link mechanism 22 by expansion and contraction thereof.
[0015]
2 and 3 are enlarged views of a connecting portion between the piston rod 28 of the arm cylinder 18 and the arm 16. A pair of left and right arm brackets 30 project from the rear end side of the arm 16, and a bent pin receiving groove 32 is formed in each arm bracket 30. For example, the pin receiving groove 32 has a U-shape, and has two end positions 34 and 36 that are spaced apart in the expansion / contraction direction of the piston rod 28 (see the arrow in FIG. 2).
[0016]
A distal end portion 38 of the piston rod 28 is provided between the left and right arm brackets 30 and is connected to the arm bracket 30 via a connecting pin 40. More specifically, the connecting pin 40 is inserted into the distal end portion 38 of the piston rod 28 via a slide bearing, and both end portions of the connecting pin 40 are fitted and supported in the pin receiving grooves 32 of the arm bracket 30. Yes.
[0017]
As shown in FIG. 4, both end portions 42 of the connecting pin 40 have a rectangular shape. When the both ends 42 of the rectangle are fitted in the pin receiving groove 32, the rotation of the connecting pin 40 is prevented in cooperation with the groove wall of the pin receiving groove 32, but in the groove direction of the pin receiving groove 32. It is relatively easy to move. Therefore, the connecting pin 40 can move along the pin receiving groove 32 between the end positions 34 and 36 described above, as indicated by a one-dot chain line in FIG.
[0018]
Further, the cylindrical portion of the connecting pin 40 between both end portions 42 has an outer diameter larger than the groove width of the pin receiving groove 32, and the connecting pin 40 is only at the insertion / removal position 44 defined in the pin receiving groove 32. The insertion and removal is allowed. As shown in FIG. 5, the insertion / removal position 44 is provided between the end positions 34, 36 and is formed by cutting both groove wall portions of the pin receiving groove 32 in an arc shape.
[0019]
In the state shown in FIG. 2, the connecting pin 40 is positioned at one end position 34 of the pin receiving groove 32, and both end portions 42 are a pair of left and right stopper plates 46 and the end wall of the pin receiving groove 32 defining the end position 34. Held by. The stopper plate 46 is fixed to the arm bracket 30 by a pair of connecting bolts 48. A pair of screw holes 50 are formed in the arm bracket 30 for the connection bolts 48, and the screw holes 50 are arranged with the pin receiving groove 32 interposed therebetween. Similarly, a pair of screw holes 50 is formed on the other end position 36 side with the pin receiving groove 32 interposed therebetween.
[0020]
When the excavator 2 is transported, the connecting pin 40 is positioned at the end position 34 (see FIG. 2) closer to the arm cylinder 18 side. However, when the excavator 2 is operated, the connecting pin 40 is positioned at the other end position 36. Positioned on.
Here, the change operation of the pin position from the end position 34 to the end position 36 can be performed by the following procedure, for example.
[0021]
First, prior to changing the pin position, the arm 16 of the excavator 2 is wound at the lower side of the boom 8 with a predetermined winding angle, and the arm 16 is held in a grounded state. At this time, as shown in FIG. 6, the pin receiving groove 32 of the arm bracket 30 is inclined such that the bent groove portion 32 a having the end position 34 at the terminal end is along the expansion / contraction direction of the arm cylinder 18 (piston rod 28). In this state, the left and right stopper plates 46 are removed. Even if the stopper plate 46 is removed in this way, both end portions 42 of the connecting pin 40 are sandwiched from both sides by the groove wall portion of the pin receiving groove 32 at the end position 34, and the arm cylinder 18 and the arm 16 are It does not move carelessly.
[0022]
In this state, when the boom 8 is gradually raised while the arm cylinder 18 (piston rod 28) is extended, the arm 16 is rotated, and the connecting pin 40 has both end portions 42 as shown in FIG. It moves from the end position 34 to the starting end in the bent groove 32a. At this time, the connection groove portion 32 c that connects the bent groove portions 32 a and 32 b of the pin receiving groove 32 is aligned with the expansion and contraction direction of the arm cylinder 18. Therefore, when the extension of the arm cylinder 18 is continued, the connecting pin 40 moves to the start end of the bent groove 32b as shown by a two-dot chain line in FIG.
[0023]
Thereafter, when the boom 8 is gradually lowered while the arm cylinder 18 is contracted, the connecting pin 40 moves in the bending groove 32b as shown in FIG. It is positioned at its end position 36. In this state, the left and right stopper plates 46 are attached to complete the changing operation.
The operation of changing the pin position from the end position 36 to the end position 34 can also be performed in the same manner by combining the expansion / contraction operation of the arm cylinder 18 and the hoisting operation of the boom 8.
[0024]
As described above, by changing the pin position of the connecting pin 40 from the end position 36 at the time of work to the end position 34 at the time of transportation closer to the arm cylinder 18 side, the maximum wrap-up angle of the arm 16 can be ensured to be larger. As shown in FIG. 9, the angle θ formed by the boom 8 and the arm 16 can be reduced. As a result, horizontal position the height H1 of the boom 8, namely, the height of the hydraulic excavator 2 during transportation Ru lower kuna. A two-dot chain line in FIG. 9 shows a state where the arm 16 is wound up to its maximum winding angle when the pin position of the connecting pin 40 is at the end position 36, and the height of the lying posture of the boom 8 in this state is shown. H2 is higher than H1.
[0025]
The above-described change operation of the pin position does not require insertion / removal of the connecting pin 40, and the change operation can be performed safely and smoothly by combining the expansion / contraction operation of the arm cylinder 18 and the hoisting operation of the boom 8.
Regardless of the pin position of the end position 34 or the end position 36, the load from the connection pin 40 is received by the groove wall portion of the pin receiving groove 32. Therefore, it is not necessary to separately provide a receiving member on the arm bracket 30 and to support the pin load with this receiving member. Further, since the load applied from the connecting pin 40 to the left and right stopper plates 46 is small, the surface pressure of the stopper plate 46 is low. Therefore, the strength required for the stopper plate 46 is low, and its wear is also suppressed.
[0026]
Only when the connecting pin 40 is held at the insertion / removal position of the pin receiving groove 32, the connecting pin 40 can be pulled out from the pin receiving groove 32, and the connecting pin 40 does not come out undesirably during the pin position changing operation. It can be done safely.
The present invention is not limited to the above-described embodiment, and various modifications can be made.
[0027]
For example, both end portions 42 of the connecting pin 40 are not limited to a rectangular shape, but may be circular end portions 42a having a smaller diameter than the cylindrical portion as shown in FIGS. In this case, end positions 34 and 36 of the pin receiving groove 32 have arcuate end walls. Thus, if both end portions 42a of the connecting pin 40 are circular, the connecting pin 40 is rotatable within the pin receiving groove 32. To prevent this rotation, the insertion groove 52 is formed on the outer periphery of the both end portions 42a. Then, the stopper plate 46 may be fixed by inserting a part of the stopper plate 46 into the insertion groove 52.
[0028]
The shape of the pin receiving groove 32 is not limited to the U-shape, and various shapes can be adopted. The pin receiving groove 32 has a larger maximum winding angle of the arm 16 in addition to the end position that defines the pin position during operation. It is sufficient to have a bent shape so that the end positions are separately provided and the end positions communicate with each other.
[0029]
【The invention's effect】
As described above, according to the hydraulic excavator of the present invention (Claim 1), the connecting pin between the arm cylinder and the arm bracket can be selectively positioned at one of both end positions in the pin receiving groove. During the transportation, the wrap angle of the arm can be made larger and the height of the hydraulic excavator can be made lower. Even if the connecting pin is in any end position, the pin load applied by the expansion and contraction of the arm cylinder is received by the groove wall portion of the bent groove , so there is no need to provide a receiving member for that purpose, and the stopper plate The bent groove portion at the selected end position cooperates with the end wall of the bent groove portion defining the end position and the groove wall portion, and holds the end portion of the connecting pin.
[0030]
The outer diameter of the connecting pin is Rimodai by the groove width of the pin receiving groove, and, both end portions of the connecting pin has a rectangular shape (aspect 2), and the retaining and detent of the coupling pin Achieved at the same time.
If the connecting pin can be inserted / removed only at the insertion / removal position in the pin receiving groove, when changing the pin position of the connecting pin, the connecting pin does not come out accidentally and the change work can be performed safely. it can.
[Brief description of the drawings]
FIG. 1 is a side view of a hydraulic excavator mounted on a trailer bed during transportation.
FIG. 2 is an enlarged side view showing a connecting portion between an arm cylinder and an arm of a hydraulic excavator.
FIG. 3 is a plan view of a connecting portion in FIG. 2;
FIG. 4 is a perspective view of a connecting pin.
FIG. 5 is a diagram showing a shape of a pin receiving groove.
FIG. 6 is a diagram for explaining a change operation of a pin position.
7 is a view showing a state in which a connecting pin moves from one end position from the state of FIG. 6;
8 is a diagram showing a state in which the connecting pin is positioned at the other end position from the state of FIG. 7;
FIG. 9 is a diagram showing the difference in the maximum wrap-up angle of the arm when the connecting pin is at the end position during work and the end position during transport.
FIG. 10 is a diagram illustrating a relationship between a connection pin and a stopper plate according to a modified example.
11 is a perspective view showing a part of the connecting pin of FIG. 10;
[Explanation of symbols]
8 Boom 16 Arm 18 Arm cylinder 30 Arm bracket 32 Pin receiving groove
32a, 32b Bent groove (groove wall part)
34, 36 End position 40 Connecting pin 42, 42a Both ends 46 Stopper plate

Claims (3)

Between the boom and the arm bracket, a boom that can be raised and lowered, an arm that is rotatably connected to the tip of the boom, has an arm bracket on one end thereof, and is attached with a work tool on the other end. In a hydraulic excavator provided with an arm cylinder for rotating the arm,
A bent pin receiving groove formed on the arm bracket and movably receiving a connecting pin provided at a tip of the arm cylinder ;
A stopper plate detachably provided on the arm bracket;
With
The pin receiving groove includes two bent groove portions that are provided apart from each other in the expansion / contraction direction of the arm cylinder, and the connection pin is selectively positioned, and a connection groove portion that connects between the bent groove portions,
Each bending groove is formed from the end wall defining two groove walls portions for clamping the ends of the connecting pins as viewed in expansion and contraction direction of the arm cylinder, a first end position or the second end position,
The groove wall portions, said first end position or the second end position said first end position or end wall and the stopper plate you define a second end position said ends of the connecting pins in the pin receiving groove It has a structure to hold in the bent groove ,
The hydraulic excavator, wherein the second end position is provided at a position where the maximum winding angle is larger than a maximum winding angle of the arm when the connecting pin is at the first end position. The groove width of the pin receiving groove is narrower than the outer diameter of the connecting pin, and both end portions of the connecting pin that fit into the pin receiving groove have a rectangular shape. Hydraulic excavator. The hydraulic excavator according to claim 1, wherein the pin receiving groove further includes an insertion / removal position that allows the connection pin to be inserted / removed from the arm bracket.

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