JP2006336291A - Boom structure for loader working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boom structure for a loader working machine attaining improvement in an operator's front visibility and eliminating the strength shortage of a connection part between a boom member and a hollow cylinder body while reducing the diameter of the hollow cylinder body. <P>SOLUTION: The boom structure for the loader working machine comprises right and left boom members 1, 1 with working tools 12 connected to the tips while the rear ends are detachably pivoted to a main frame 14 of a cargo handling vehicle 5 such as a tractor through side frames 15; and the hollow cylinder body 2 inserted and stuck into insertion holes 1f, 1f formed in the boom members 1, 1 to connect the right and left boom members 1, 1. Stress supporting members 3, 3 are provided in the hollow cylinder body 2 in the connected positions of the right and left boom members 1, 1 and hollow cylinder body 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cargo handling vehicle used for agricultural and civil engineering work such as a tractor-mounted loader and a self-propelled loader (wheel loader, self-propelled backhoe, power shovel, etc.) equipped with a front loader and / or a backhoe. The present invention relates to a boom structure for a loader work machine that is employed.

Conventionally, as a boom adopted for a tractor-mounted loader, left and right boom members that have a working tool connected to the front end and a rear end that is pivotally supported detachably on a main frame of a cargo handling vehicle such as a tractor via a side frame; In addition, there is a structure including a hollow cylinder body that is inserted and fixed in an insertion hole formed in the boom member in order to connect the left and right boom members (see, for example, Patent Document 1). The reason for using the hollow cylinder is for weight reduction and the like.
Japanese Utility Model Publication No. 6-53648

Conventionally, the outer diameter of the hollow cylinder connecting the left and right boom members has been configured to be larger than the side wall width of the left and right boom members, which hinders the driver's front view, The remaining dimension of the side wall width of the boom member at the connecting portion between the left and right boom members and the hollow cylindrical body is reduced, the strength is lowered, and cracks are easily generated.
In order to solve this problem, if the outer diameter of the hollow cylinder is reduced, there is a new problem that the strength is insufficient.
Conventionally, both ends of the hollow cylindrical body are kept open, and the above-mentioned Patent Document 1 describes a configuration in which the left and right ends of the hollow cylindrical body are closed with lids. The lid was intended to prevent rainwater and dust from entering the hollow cylindrical body.

The attachment positions of the lid body in Patent Document 1 above are both ends of the hollow cylinder, and this position is shifted outward from the connection part between the left and right boom members and the hollow cylinder, so the upper side of the connection part. Or the stress which acts on the lower side wall cannot be carried on the lid.
The present invention has been proposed in view of the above-described problems, and its object is to solve the shortage of the strength of the connecting portion between the boom member and the hollow cylinder while reducing the outer diameter of the hollow cylinder. Another object is to provide a boom structure for a loader working machine that can improve the forward visibility of the driver.

In order to achieve the above-mentioned object, the present invention includes a left and right boom member having a work tool connected to a front end and a rear end pivotally supported by a main frame of a cargo handling vehicle such as a tractor via a side frame, In a boom structure for a loader working machine, including a hollow cylinder body that is inserted and fixed in an insertion hole formed in the boom member in order to connect the left and right boom members, the connection between the left and right boom members and the hollow cylinder body A stress carrying member is provided in the hollow cylinder at the position.
The left and right boom members have a box-shaped cross section, and the hollow cylindrical body is inserted and fixed in the insertion hole through the insertion hole formed in the box-shaped cross section in the left-right direction, and the stress carrying member Is preferably provided at a position in the hollow cylinder substantially coinciding with the outer surface of the box-shaped cross section of the left and right boom members.

  The left and right boom members may include annular flanges around the insertion hole.

According to the present invention, the sidewalls of the left and right boom members are inserted into the insertion holes by forming the continuous stress carrying surfaces by filling the gaps of the insertion holes with the stress carrying members provided in the hollow cylinders even at the positions of the insertion holes. The strength of the hollow cylinder itself at the position can be improved, whereby the strength of the connecting portion between the boom member and the hollow cylinder can be increased.
As a result, the outer diameter of the hollow cylinder is reduced, the driver's forward visibility is improved, the remaining dimension of the side wall width of the boom member is increased, and the connecting portion between the boom member and the hollow cylinder is increased. Insufficient strength can be resolved.

  In addition, when an annular flange is provided around the insertion hole, the strength of the connecting portion between the left and right boom members and the hollow cylinder can be further increased.

Embodiments according to the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment of a tractor-mounted loader to which the present invention is applied. Reference numeral 4 denotes a front loader 6 mounted on the front portion of a tractor 5 exemplified as a cargo handling vehicle having a boom. A tractor-mounted loader.
The tractor 5 has a pair of left and right front and rear wheels 7 and 8, and a bonnet 9 that covers an engine, a radiator, and the like is provided at a front portion.

The front loader 6 mainly includes an attachment frame 10, a boom member 1, and a work tool 12 such as a bucket.
The mounting frame 10 is provided on a lower portion of the front portion of the tractor 5 (lower side of the rear end side of the bonnet 9), and a support base 13 provided in a laterally outward projecting manner from the tractor 5, A main frame 14 includes a main frame 14 projecting upward from the support base 13 and a side frame 15 detachably attached to the main frame 14.
A pair of left and right boom members 1 are provided and arranged on both left and right sides of the bonnet 9. The left and right boom members 1 are connected to each other by a cylindrical hollow cylinder 2 on the front side thereof.

Each of the left and right boom members 1 has a base end side (rear end side) pivotally connected to an upper portion of the side frame 15 by a pin 17 so as to be pivotable about an axis in the left-right direction so as to be swingable up and down. Yes.
Further, a boom cylinder 18 composed of a double-acting hydraulic cylinder is interposed between the middle part in the longitudinal direction of the left and right boom members 1 and the middle part in the vertical direction of the left and right side frames 15. The boom member 1 can swing up and down.

In addition, the front end side (front end side) of each of the left and right boom members 1 is pivotally connected to the lower rear portion of the work tool 12 by a pin 19, and between the rear surface of the work tool 12 and the vicinity of the front ends of the left and right boom members 1. Both ends of the bi-folded and stretched link 20 are connected by pins 21 and 22, and double-acting between the upper surface in the longitudinal direction of each of the left and right boom members 1 and the intermediate connection point of the double-folded and stretched link 20. A bucket cylinder 24 composed of a hydraulic cylinder is interposed, and the work tool 12 can be swung (squeezed and dumped) by expansion and contraction of the bucket cylinder 24.
2A and 3 are a side view and a plan view showing the main part of the boom structure for a loader working machine according to the present invention, in which left and right boom members 1, 1 and a hollow cylindrical body 2 connecting them are shown. It has. The left and right booms 1 and 1 are symmetrical to each other, and the detailed structure of one of them will be described.

The boom member 1 includes a front boom structural body 1A and a rear boom structural body 1B formed by bending one plate material (steel plate or the like) so as to have an open U-shaped cross section on the lower side. These are connected and configured to weld a pair of left and right side plates 1C, 1C and an upper surface central connecting plate 1D to form a mountain shape as a whole, and the bottom plates 1E, 1E are welded over the entire length in the longitudinal direction. It has a box-shaped cross section.
The front boom structure 1A has a top plate portion 1a at a central portion in the width direction, which is a plate material (steel plate or the like) that has been gradually widened from the front end side to the rear end side in the longitudinal direction. The side edges in the width direction from 1a are bent at a right angle to the lower side to form a U-shaped cross section having left and right side walls 1b and 1b. The rear boom structural body 1B is also configured in the same manner as the front boom structural body 1A, and those having the same shape are used, but separate bodies may be used.

In the front boom constituting body 1A, through holes 1f and 1f are formed through the left and right side walls 1b and 1b at a position corresponding to the mounting position of the hollow cylindrical body 2 in a penetrating state. In the present embodiment, the case where the annular flanges 1g and 1g are formed around the insertion holes 1f and 1f so as to protrude outward in the cross section of the front boom structure 1A by burring or the like is illustrated.
The pivot boss members 1h and 1i having the same shape are attached to the front end of the front boom structure 1A and the rear end of the rear boom structure 1B. A stand pivot support bracket 1j is attached to the lower surface on the front end side of the front boom structure 1A. Note that the stand (not shown) is for holding the front loader 6 removed from the cargo handling vehicle 5 such as a tractor independently from the ground.

A pair of left and right side plates 1C and 1C are respectively provided with a pivot supporting boss member 1k for attaching a bucket cylinder on the upper tip side and a supporting boss member 1n for attaching a boom cylinder on the lower rear end side.
As best shown in FIGS. 2B and 2C, a hollow cylinder 2 made of a steel round pipe or the like is inserted through the insertion holes 1f and 1f of the front boom structure 1A in a penetrating manner. It is welded at the annular flanges 1g and 1g around 1f. In the hollow cylinder 2, stress carrying members 3 and 3 are integrally welded. As shown in FIGS. 2 (B) and 2 (C), the mounting positions of the stress carrying members 3 and 3 are within the hollow cylindrical body 2 that substantially coincides with the outer surfaces of the left and right side walls 1b and 1b of the left and right boom members 1 and 1, respectively. It is provided in the position. The stress carrying members 3 and 3 use the waste material or the like of the front boom structural body 1A. In the present embodiment, the stress carrying members 3 and 3 are exemplified by the disk shape, but are limited to the disk shape. Alternatively, it may be a polygon, a star, an ellipse, or the like.

  By providing the stress carrying members 3 and 3 at the above-described positions, the gaps between the insertion holes 1f and 1f are filled at the positions of the insertion holes 1f and 1f of the left and right boom members 1 and 1, respectively. The side walls 1b and 1b form a continuous stress carrying surface. Thereby, the strength of the hollow cylinder 2 itself at the positions of the insertion holes 1f and 1f can be improved. As a result, the outer diameter of the hollow cylinder 2 can be reduced to improve the forward visibility of the driver. it can. Along with this, the remaining dimensions of the side walls 1b, 1b of the left and right boom members 1, 1 can be increased, and the strength at the connecting portion between the left and right boom members 1, 1 and the hollow cylindrical body 2 can be increased. And the occurrence of cracks can be prevented.

4 and 5 show another embodiment of the present invention. Reference numeral 4 denotes a tractor-mounted loader in which a front loader 6 is mounted on the front portion of the tractor 5.
The tractor 5 has a pair of left and right front and rear wheels 7 and 8, and a bonnet 9 that covers an engine, a radiator, and the like is provided at a front portion.
The front loader 6 is mainly composed of an attachment frame 10, a boom member 11, and a work tool 12 such as a bucket.

The mounting frame 10 is provided on a lower portion of the front portion of the tractor 5 (lower side of the rear end side of the bonnet 9), and a support base 13 provided in a laterally outward projecting manner from the tractor 5, A main frame 14 includes a main frame 14 projecting upward from the support base 13 and a side frame 15 detachably attached to the main frame 14.
A pair of left and right boom members 11 are disposed on the left and right sides of the bonnet 9, and the left and right boom members 11 are connected to each other by a cylindrical hollow cylinder 16 on the front side thereof.

Each of the left and right boom members 11 has a base end side (rear end side) pivotally connected to an upper portion of the side frame 15 by a pin 17 so as to be pivotable about an axis in the left-right direction so as to be swingable up and down. Yes.
Further, a boom cylinder 18 composed of a double-acting hydraulic cylinder is interposed between a longitudinal middle portion of each of the left and right boom members 11 and a vertical middle portion of each of the left and right side frames 15. The boom member 11 can swing up and down.

  Further, the front end side (front end side) of each of the left and right boom members 11 is pivotally connected to the lower rear portion of the work tool 12 by a pin 19, and between the rear surface of the work tool 12 and the vicinity of the front ends of the left and right boom members 11. Both ends of the bi-folded link 20 are connected by pins 21 and 22, and a substantially triangular link plate 23 is swingably attached to the upper surface of the middle part in the longitudinal direction of each of the left and right boom members 11. A bucket cylinder 24 composed of a double-acting hydraulic cylinder is interposed between the intermediate link 23 and the intermediate connection point of the double-folded link 19, and the working tool 12 can be swung by the expansion and contraction of the bucket cylinder 24 (squeeze dump It can be operated).

The link plate 23 is connected to the upper portion of the side frame 15 via a link rod 25 via a pin 26. The pins 19 and 21 on the work tool 12 side and the pins 17 and 26 on the side frame 15 side are configured to have a parallelogram arrangement (a parallelogram link mechanism is configured).
Thus, when the boom cylinder 18 is expanded and contracted to swing the boom member 11 up and down, the work tool 12 is configured to move parallel to the ground. In this case, of course, when the bucket cylinder 24 is expanded and contracted, the work tool 12 can be independently swung up and down (dump / squeeze operation).

As shown in FIGS. 4 and 5, each of the left and right boom members 11 described above is a chevron-shaped curve whose center in the longitudinal direction is convex upward so as to match the design of the curved shape of the upper surface of the bonnet 9. In addition, the vertical width is gradually increased from the front and rear ends to the center in the longitudinal direction.
In addition, the boom member 11 includes a front boom constituent body 11A from the center in the longitudinal direction to the front rear boom constituent body 11B from the center in the longitudinal direction, and the boom constituent bodies 11A and 11B before and after the boom member 11. Is mainly composed of a pair of left and right side plates 11C, 11C disposed on the left and right sides of the center in the longitudinal direction, and an upper surface center coupling plate 11D that is coupled on the boom member 11 on the upper surface side in the longitudinal direction.

The front and rear boom constituent bodies 11A and 11B are symmetrical to each other, and each of the plate members (steel plates, etc.) obtained by taking a plate with the width gradually increased from one end to the other end in the longitudinal direction. The center part is a top plate part, both side edges in the width direction are bent at right angles to the lower side from the top plate part, and left and right side walls are formed in a U-shaped cross section that is open on the lower side. 11E is welded over the entire length in the longitudinal direction to form a box-shaped cross section.
An insertion hole 11 f is formed in the front boom constituting body 11 </ b> A at a position corresponding to the attachment position of the hollow cylindrical body 16. An annular flange may be formed around the insertion hole 11f so as to protrude outward in the cross section of the front boom constituting body 11A by burring or the like, or may be omitted.

The pivot boss members 11h and 11i having the same shape are attached to the front end of the front boom structure 11A and the rear end of the rear boom structure 11B.
A hollow cylinder 16 made of a steel round pipe or the like is inserted through the insertion hole 11f of the front boom structure 11A in a penetrating state, and is welded around the insertion hole 11f. The stress carrying member 3 is integrally welded into the hollow cylinder 16. The mounting position of the stress carrying member 3 is provided at a position in the hollow cylinder 16 that substantially coincides with the outer surfaces of the left and right side walls of the left and right boom members 11 and 11. In addition, the stress carrying member 3 uses the waste material etc. of the front boom structure 11A, The shape may be any of disk shape, polygon, star shape, ellipse shape, etc.

  By providing the stress carrying member 3 at the above position, stress carrying is performed in which the side walls of the left and right boom members 11 and 11 are continuously filled at the positions of the through holes 11f of the left and right boom members 11 and 11 by filling the gaps of the through holes 11f. Surfaces can be formed to distribute stress. As a result, the strength of the hollow cylinder 16 itself at the position of the insertion hole 11f can be improved. As a result, the outer diameter of the hollow cylinder 16 can be reduced, and the forward visibility of the driver is improved. Can be planned. Moreover, the upper or lower remaining dimension of the left and right boom members 11, 11 can be increased, and the strength of this portion can be increased to prevent the occurrence of cracks.

  The embodiment shown in FIGS. 4 and 5 is configured as described above. According to this configuration, the front boom structure 11A and the rear boom structure 11B are symmetrically formed of the same parts, thereby improving productivity and unifying parts. Cost reduction can be achieved by making it easier. Further, each of the left and right boom members 11 is formed in a mountain-shaped curved shape with the center portion in the longitudinal direction protruding upward, so that the driver's forward visibility is improved and the curved shape of the upper surface of the bonnet 9 is designed. The design is improved because of the matching shape. Furthermore, when the left and right boom members 11 are moved up and down, the link rod 25 of the parallelogram link mechanism for translating the work tool 12 has a curved shape similar to the curved shape of the rear boom component 11B. The driver's forward visibility and design are improved.

It is a side view of the tractor mounting type loader concerning a 1st embodiment of the present invention. (A) is an enlarged side view of the boom in FIG. 1, (B) is a sectional view taken along line BB of (A), and (C) is a partially enlarged view of (B). It is a top view of the boom of FIG. It is a side view of the tractor mounting type loader concerning a 2nd embodiment of the present invention. FIG. 5 is an enlarged side view of the boom in FIG. 4 in an exploded state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Boom member 2 Hollow cylinder 3 Stress carrying member 4 Tractor-mounted loader 5 Cargo handling vehicle (tractor)
6 Front loader 7 Front wheel 8 Rear wheel 9 Bonnet 10 Mounting frame 12 Work tool (bucket)
13 Support Base 14 Main Frame 15 Side Frame 18 Boom Cylinder 24 Bucket Cylinder

Claims (3)

  Left and right boom members (1) having a work tool (12) connected to the front end and a rear end pivotally supported in a detachable manner on a main frame (14) of a cargo handling vehicle (5) such as a tractor via a side frame (15). ) (1) and a hollow cylinder (2) inserted and fixed in an insertion hole (1f) formed in the boom members (1) (1) in order to connect the left and right boom members (1) (1). ) Provided with a stress carrying member (3) in the hollow cylinder (2) at a position where the left and right boom members (1) (1) and the hollow cylinder (2) are connected. ) A boom structure for a loader working machine provided with (3).   The left and right boom members (1) and (1) have a box-shaped cross section, and the hollow cylindrical body (2) passes through an insertion hole (1f) formed in the box-shaped cross section in the left-right direction. The stress carrying member (3) is inserted into and fixed to the hole (1f), and the stress carrying member (3) in the hollow cylinder (2) substantially coincides with the outer side surface of the box-shaped cross section of the left and right boom members (1) (1). The boom structure for a loader working machine according to claim 1, wherein the boom structure is provided at a position.   The boom structure for a loader working machine according to claim 1 or 2, wherein the left and right boom members (1) (1) include an annular flange (1g) around an insertion hole (1f).

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