JP7595503B2 - Work Machine - Google Patents

Description

The present invention relates to a work machine.

In a conventional crane, a vehicle frame is provided with an axle that extends in the width direction of the vehicle frame, and a side frame is supported by an extension beam provided at the tip of the axle.
The side frames have holes into which the axles can be inserted, and when the crane is not in operation (such as during transportation), the side frames can be moved widthwise inward of the vehicle frame, making the vehicle frame smaller in width.
In this case, the extension beam provided at the tip of the axle could be rotated and folded by a vertical support shaft (see, for example, Patent Document 1).

JP 2016-221994 A

In the above crane, the vertical support shaft of the extension beam may rise, which may interfere with the side frame and hinder the expansion and contraction of the side frame.

The present invention aims to provide a work machine that allows the side frames to move smoothly relative to the body frame.

The present invention relates to
The vehicle frame,
side frames arranged on both sides of the vehicle body frame in a width direction;
an axle beam extending in the width direction from the vehicle body frame and inserted into the side frame;
an extension beam that can be rotated about a pivot pin between two positions, an extended position and a folded position, relative to the axle beam;
A work machine having
The rotation pin has a support axis extending in the front-rear direction.

The present invention makes it possible to provide a work machine that allows the side frame to move smoothly relative to the body frame.

1 is a perspective view of a lower traveling body of a work machine according to an embodiment of the present invention. FIG. FIG. 2 is a perspective view showing a part of the tip of the axle beam cut away. 1 is an enlarged perspective view of a connection portion between a side frame of the left traveling device and an axle beam. FIG. 13 is a cross-sectional view of the connection between the side frame and the axle beam when the extension beam of the left traveling gear is in an extended state. FIG. 13 is a cross-sectional view of the connection between the side frame and the axle beam when the extension beam of the left traveling gear is in a folded state. FIG. 13 is a perspective view of storage sections for a convex member, a contact member, and a fixing pin provided on a side frame. FIG. FIG. 13 is a side view showing a case where a linkage mechanism is provided on the traveling device. 11 is a cross-sectional view of the extension beam and its surroundings, showing the interlocking mechanism when the extension beam is in the extended position. FIG. 11 is a cross-sectional view of the extension beam and its surroundings, showing the interlocking mechanism when the extension beam is in the folded position. FIG. FIG. 11 is a side view showing a case where a side weight is provided on the traveling device.

[Overview of the embodiment]
Hereinafter, an embodiment of a work machine according to the present invention will be described with reference to the drawings.
A crawler crane is shown as an example of the work machine of this embodiment.
The crawler crane has a lower traveling body 1, an upper rotating body rotatably mounted on the lower traveling body 1 via a slewing ring, and a boom journaled on the upper rotating body so as to be rotatable up and down.
In this embodiment, since the components other than the lower traveling body 1 are well known, illustrations and detailed descriptions thereof will be omitted.

FIG. 1 is a perspective view of a lower carrier 1 of a crawler crane.
In the following description, the forward direction of the crawler crane (work machine) is referred to as the front, the backward direction as the rear, the horizontal direction perpendicular to the front-to-rear direction as the left-right direction, one vertical direction as the top and the other as the bottom. The left-right direction may also be referred to as the width direction.

The lower running body 1 has a body frame 11 with a slewing wheel at the top, a total of four axle beams 12 extending left and right at the front and rear of the body frame 11, a pair of running devices 13 provided on the left and right of the body frame 11, and weights 14 provided on the front and rear of the body frame 11. The body frame 11 may also be provided with a jack-up device for raising and lowering the body frame 11 for moving the running devices 13, which will be described later.

[Axle beam]
2 is a cutaway perspective view of the tip of the axle beam 12 in a vertical and horizontal cross section. Each axle beam 12 includes an upper plate 121, a lower plate 122, a pair of vertical plates 123 (only one of which is shown in FIG. 5), and a bulkhead 124.
The upper plate 121, the lower plate 122 and the pair of vertical plates 123 are joined together to form a hollow frame with a rectangular cross section when viewed from the left-right direction. The tip of the axle beam 12 is wide open, and a partition wall 124 is provided to close the deep part. The space from the tip opening of the axle beam 12 to the partition wall 124 becomes a storage area H for the extension beam 20 described later.

Support brackets 125 extending in the direction of extension of the axle beam 12 are provided at the lower ends of the left and right vertical plates 123 (only one is shown in FIG. 5). These support brackets 125 rotatably support the extension beam 20 described below. The pair of support brackets 125 have through holes 126 penetrating in the front-rear direction, and support the pivot pin 21 that serves as the pivot axis of the extension beam 20 in parallel in the front-rear direction. The extension beam 20 described below is rotatably supported by the pivot pin 21 between the pair of support brackets 125.

[Running device: schematic configuration]
The left and right traveling devices 13 are each supported by two axle beams 12 at the front and rear of the body frame 11 .
The left-side traveling device 13 and the right-side traveling device 13 have a structure that is plane-symmetrical with respect to a vertical plane along the front-rear direction. In other words, by switching the left-side traveling device 13 left and right, it has the same structure as the right-side traveling device 13. For this reason, in the following explanation, the configuration of the left-side traveling device 13 will be explained, and the configuration of the right-side traveling device 13 will be denoted by the same reference numerals as the left-side traveling device 13 and explanations thereof will be omitted.

FIG. 3 is an enlarged perspective view of a connection portion between the side frame 131 of the left traveling device 13 and the axle beam 12, and FIGS. 4 and 5 are cross-sectional views taken along a vertical plane extending in the left-right direction of the same connection portion.
The traveling device 13 includes a side frame 131 , a traveling drive device 132 , and a crawler belt (track) 133 .
The traveling drive device 132 includes a driving wheel rotatably supported near the rear end of each side frame 131 and a traveling hydraulic motor (both not shown) that drives the driving wheel.
An upper roller (not shown), a lower roller 134, and an idler (not shown) are provided on the upper, lower, and rear portions of the side frame 131. The crawler belt 133 is attached to the upper roller, the lower roller 134, the idler, and the drive wheel so as to be stretched across them.

[Traveling device: fitting part]
The side frame 131 is provided with two fitting portions 135, one at the front and one at the rear, into which the front and rear axle beams 12 are individually fitted. As shown in Figures 4 and 5, each fitting portion 135 has a rectangular frame shape in a side view, and the axle beam 12 is inserted and connected inside the fitting portion 135.

In addition, the traveling device 13 can move in the left-right direction along the axle beam 12 with the axle beam 12 inserted into the fitting portion 135. The traveling device 13 shown with a solid line in Fig. 1 indicates a state in which the vehicle body width is contracted when moved to the left (inside in the left-right direction) with respect to the vehicle body frame 11, and the traveling device 13 shown with a two-dot chain line in Fig. 1 indicates a state in which the vehicle body width is expanded when moved to the right (outside in the left-right direction) with respect to the vehicle body frame 11.
In addition, between each side frame 131 and the body frame 11, for example, a hydraulically driven telescopic cylinder (not shown) is provided, and the traveling device 13 can be switched between a contracted state and an extended state.

[Extended beam: schematic configuration]
As shown in FIGS. 3 to 5, an extension beam 20 is supported at the tip of the axle beam 12 by a pivot pin 21 so as to be rotatable (foldable).
As described above, the pivot pin 21 is held parallel in the fore-and-aft direction by the axle beam 12 .
Therefore, by rotating the extension beam 20, it can be switched between an extended position (where the rotating end is extended to the left (in the extension direction of the axle beam 12)) and a folded position (where the rotating end is facing upward).

The extension beam 20 has an extension beam main body 22 rotatably supported by a pivot pin 21, an extension beam connecting portion 23 extending from the extension beam main body 22 toward the pivot end side and connecting to an inlay portion 135 of the side frame 131, a contact surface member 24 detachably attached to the extension beam main body 22, and a fixing pin 25 connecting the extension beam connecting portion 23 and the inlay portion 135.

[Extension beam: Extension beam main body]
The extension beam body 22 has a pair of vertical plates 221 aligned in the front-rear direction. The pair of vertical plates 221 are integrally connected at positions corresponding to the right end and the lower end of the extension beam 20 when the extension beam 20 is in the extended position.

Each vertical plate 221 is a flat plate parallel to a vertical plane along the left-right direction. When the extension beam 20 is in the extended position, a first insertion hole 222 through which the pivot pin 21 is inserted is provided at a position that is the lower right of each vertical plate 221. In addition, from the upper end to the left end of each vertical plate 221, an arc shape is formed with the pivot pin 21 as the center. This is to avoid interference with the axle beam 12 when the extension beam 20 rotates.
When the extension beam main body 22 is rotated from the extended position to the folded position with the contact surface member 24 removed, it can be stored in a storage area H provided at the tip of the axle beam 12, as shown in Figure 5.
The extension beam main body 22 rotates together with the extension beam connecting portion 23, and as shown in Figure 5, in the folded position, the extension beam connecting portion 23 is positioned so as to be contained inside the crawler belt 133 in the left-right direction.

When the extension beam 20 is in the extended position, a second insertion hole 224 is formed above the first insertion hole 222 of each vertical plate 221. A removable stopper pin 26 is inserted into the second insertion hole 224 of each vertical plate 221. The stopper pin 26 fits into a recess 127 formed in the upper part of a pair of support brackets 125 of the axle beam 12 to restrict the rotation of the extension beam 20 so that the extension beam 20 does not move downward from the extended position. In other words, the stopper pin 26 may be any rotation restriction part that can restrict the rotation of the extension beam 20 so that the extension beam 20 does not move downward from the extended position. For example, a rotation restriction part that contacts the lower plate 122 of the axle beam may be provided below the vertical plate 221. Even with this configuration, the rotation of the extension beam 20 can be restricted so that the extension beam 20 does not move downward from the extended position.

Further, two mounting holes 223 for mounting the contact surface member 24 are formed near the arcuate outer edge of each vertical plate 221 .
The contact surface member 24 has a convex member 241 and an abutment member 242, and the convex member 241 is attached between the two vertical plates 221. Two insertion holes 241d are formed in the convex member 241, and the attachment pins 27 are inserted into the insertion holes 241d by aligning them with the two attachment holes 223 of the vertical plates 221 on both sides. In this way, the convex member 241 of the contact surface member 24 is fixed to the extension beam main body 22.
A spring-loaded lock pin 271 is attached to the insertion end of each mounting pin 27 to prevent accidental removal.

[Extension beam: extension beam connection part and fixing pin]
The extension beam connecting part 23 is a flat plate that is horizontally fixed to the lower part of the extension beam main body 22 when the extension beam 20 is in the extended position. The extension beam connecting part 23 extends toward the rotation end side (leftward) from the extension beam main body 22. An insertion hole 231 for the fixing pin 25 that penetrates vertically is formed at the extended end of the extension beam connecting part 23.

When the fixing pin 25 is inserted from above into the insertion hole 231 of the extension beam connecting portion 23 , the lower end portion protrudes downward from the lower surface of the extension beam connecting portion 23 .
A connecting hole 135b into which the lower end of the fixing pin 25 is inserted is formed in the lower plate 135a of the fitting portion 135 of the side frame 131.
When the lower end of the fixing pin 25 protruding downward from the underside of the extension beam connecting portion 23 is inserted into the connecting hole 135b of the fitting portion 135, the running device 13 can be fixed in a position where the vehicle width is expanded as described above.

A stop pin 251 can be attached near the attachment position of the fixing pin 25 on the upper surface of the extension beam connecting part 23. The stop pin 251 is arranged to cross the head of the fixing pin 25 inserted into the insertion hole 231, and prevents the fixing pin 25 from coming out.

[Extension beam: contact surface component]
As described above, the contact surface member 24 has the convex member 241 and the contact member 242 .
As shown in Figs. 3 and 4, the protruding member 241 is made of two overlapping thick plates, and has an elbow shape extending in two directions when viewed from the front-rear direction.
The two insertion holes 241d described above are formed in one of the extending portions 241b of the convex member 241, and the extending portion 241b is held by the extension beam main body 22.
The other extension portion 241a of the convex member 241 extends in the extension direction of the axle beam 12 (the direction of insertion into the fitting portion 135) when the extension beam 20 is in the extended position.
The extending portion 241a is adjacent to the lower surface of the upper plate 135c of the fitting portion 135 over almost the entire length in the extending direction.
Normally, the extension portion 241a of the convex member 241 is slightly separated from the upper plate 135c of the fitting portion 135 and does not come into contact with it, but in the event that a large load is applied to the lower running body 1, the extension portion 241a abuts against the upper plate 135c of the fitting portion 135, thereby maintaining the posture of the lower running body 1.

The convex member 241 has an opposing surface 241c at the end opposite to the extension direction of the extension portion 241a, which faces the tip surface (left end surface) of the upper plate 121 of the axle beam 12.
3 and 4, when the extension beam 20 is in the extended position, a predetermined gap is formed between the opposing surface 241c of the convex member 241 and the tip surface of the upper plate 121. The abutment member 242 of the abutment surface member 24 is attached to the upper part of the extension beam main body 22 while being inserted into this gap.

The abutment member 242 is a thick plate, and a recess 242a is formed at the lower end, the width of which is the same as or slightly wider than the front-rear width of the extension beam main body 22. The abutment member 242 can fit the upper part of the extension beam main body 22 into the recess 242a.

The contact member 242 has a width in the front-rear direction set to be sufficiently wider than the width of the protruding member 241 in the front-rear direction.
The abutting member 242 is inserted into the gap between the opposing surface 241c of the convex member 241 and the tip surface of the upper plate 121. In this arrangement, when a load is applied to the vehicle body frame 11, a force is applied to the extension beam 20 so as to rotate it toward the folded position. At this time, since the abutting member 242 is inserted into the gap between the opposing surface 241c of the convex member 241 and the tip surface of the upper plate 121, a large pressing force is applied to the abutting member 242 from the opposing surface 241c of the convex member 241. The abutting member 242 is sufficiently wider in the front-rear direction than the opposing surface 241c, and abuts against the tip surface of the upper plate 121 over a wide range in the front-rear direction, so that the pressing force from the convex member 241 can be dispersed.
Therefore, deformation of the convex member 241, the abutment member 242 or the upper plate 121 can be suppressed, and the posture of the lower running body 1 can be stably maintained for a long period of time.

In addition, since the abutment member 242 is designed to abut against the upper plate 121 located at the top of the axle beam 12, the distance to the pivot pin 21, which serves as the rotation axis, is longer, and the pressing force applied to the extension beam 12 can be reduced.
In addition, the abutting member 242 does not have to abut against the upper plate 12 as long as it can press the axle beam 12. For example, it may abut against the vertical plate 123 of the axle beam 12. Furthermore, if the abutting member 242 is structured to abut against the vertical plate 123 at a position lower than the upper plate 121, an opposing surface facing the vertical plate 123 of the axle beam 12 may be formed at the upper end of the pair of vertical plates 221 (the upper end at the extended position of the extension beam 20), and the abutting member 242 may be disposed between the opposing surface and the vertical plate 123. This allows the extension position and the folding position to be switched simply by removing the abutting member 242. In this case, the convex member 241 is no longer essential, and can be omitted.

Also, the convex member 241 may not be omitted, and may be stored between the pair of vertical plates 221. For example, the convex member 241 may be composed of two link members connected at one end to form a V-shape, and both ends of the fork of the V-shape are connected between the pair of vertical plates 221 so as to be rotatable around an axis along the front-rear direction with respect to the vertical plates 221. As a result, the connecting portion (bottom of the V-shape) of the two link members is in a position extended obliquely upward, and the extended connecting portion of the link member replaces the above-mentioned extension portion 241a and functions to abut against the upper plate 135c of the fitting portion 135 to maintain the position of the lower running body 1 when a large load is applied to the lower running body 1, for example.
Furthermore, by making the connecting portions of the two link members separable from each other, or by making one of the link members splittable in the middle in the longitudinal direction, it is possible to rotate and store it inside the pair of vertical plates 221. In this case, there is no need for space in the side frame 131 to provide a storage portion 136 for the protruding member 241, which will be described later, and the space on the side surface of the side frame 131 can be saved or used for other purposes.

[Storage section]
FIG. 6 is a perspective view of the protruding member 241, the contact member 242, and the storage portions 136, 137, and 138 for the fixing pin 25 provided on the side frame 131. As shown in FIG.
When the extension beam 20 is in the folded position, the convex member 241 and the abutment member 242 of the contact surface member 24 are removed from the extension beam main body portion 22 , and the fixing pin 25 is removed from the extension beam connecting portion 23 .
Therefore, when the extension beam 20 is in the folded position, the convex member 241, the abutting member 242, and the fixing pin 25 are stored in the respective storage portions 136, 137, and 138.

The storage section 136 of the convex member 241 is a round bar-shaped protrusion that protrudes leftward from the left surface of the side frame 131. The convex member 241 is locked when the two protrusions of the storage section 136 are individually inserted into the two insertion holes 241d of the convex member 241. The tips of the two protrusions of the storage section 136 are provided with locking claws facing upward, which can prevent the convex member 241 from falling off the two protrusions.

The storage section 137 of the abutment member 242 is a bracket that supports the left, front, and rear surfaces of the abutment member 242 from the inner bottom surface of the recess 242a of the abutment member 242. The storage section 137 holds the periphery of the portion that protrudes downward relative to the recess 242a on both sides of the recess 242a, so that the abutment member 242 can be stably held even if a force is applied in any direction, whether front, back, left, or right.

The storage section 138 for the fixing pin 25 is a bracket with a recess into which the fixing pin 25 is inserted from above. A stop pin 251 can also be attached to this storage section 138 so that it crosses the head of the fixing pin 25, allowing the fixing pin 25 to be stably held in the storage section 138.

In addition, each side frame 131 is provided with two fitting sections 135, into which the extension beams 20 are individually inserted. Therefore, two sets of the storage sections 136, 137, and 138 are provided corresponding to each extension beam 20.

[Travel gear position changeover work]
Next, the position switching operation of the traveling device 13 in the lower traveling body 1 of the crawler crane will be described with reference to Figs.
First, a case will be described in which the traveling device 13 is switched from a contracted state in which the vehicle body width is contracted, in which the traveling device 13 is located on the inner side in the left-right direction, to an expanded state in which the vehicle body width is expanded.

5 and 6, the extension beam main body 22 and the extension beam connecting portion 23 of the extension beam 20 in the folded position are rotated toward the extended position. Then, in the extended position, the stopper pin 26 is inserted into the second insertion hole 224 of the extension beam main body 22, and the stopper pin 26 is fitted into the recess 127 of the axle beam 12. As a result, the extension beam main body 22 and the extension beam connecting portion 23 are positioned at the extended position without rotating downward from the extended position.
Furthermore, the convex member 241 is removed from the storage portion 136 and attached to the extension beam main body 22 by the mounting pin 27. Then, the abutment member 242 is removed from the storage portion 137 and inserted between the opposing surface 241c of the convex member 241 and the tip surface of the upper plate 121 of the axle beam 12.
In this state, the telescopic cylinder provided between the side frame 131 and the body frame 11 is operated to move the traveling device 13 to a position where the body width is expanded.
Then, the fixing pin 25 is removed from the storage portion 138 and inserted into the insertion hole 231 of the extension beam connecting portion 23 and the connecting hole 135b of the lower plate 135a of the fitting portion 135 as shown in FIG.
As a result, the extension beam 20 is connected to the side frame 131, and the switching from the contracted state of the vehicle body width to the expanded state of the vehicle body width is completed.

Next, a case will be described where the traveling device 13 is switched from a state in which the vehicle body width is expanded, in which the traveling device 13 is positioned on the outer side in the left-right direction, to a state in which the vehicle body width is contracted.
As shown in FIG. 4 , the stop pin 251 and the fixing pin 25 are pulled out from the extension beam connecting portion 23 of the extension beam 20 in the extended position, and are stored in the storage portion 138 .
In this state, the telescopic cylinder provided between the side frame 131 and the body frame 11 is operated to move the traveling device 13 to a position where the body width is contracted.
Then, the abutment member 242 is removed from between the opposing surface 241 c of the convex member 241 and the tip surface of the upper plate 121 of the axle beam 12 , and stored in the storage section 137 .
In addition, the lock pin 271 a and the mounting pin 27 are pulled out from the extension beam main body 22 , and the convex member 241 is removed and stored in the storage section 136 .
Furthermore, the stopper pin 26 is pulled out from the extension beam main body 22, and the extension beam main body 22 and the extension beam connecting portion 23 are rotated from the extended position to the folded position.
As a result, the extension beam main body 22 is stored in the storage area at the tip of the axle beam 12, and the switching from the expanded vehicle width state to the contracted vehicle width state is completed.

Technical Effects of the Invention Embodiments
The lower running body 1 of the crawler crane has a support axis extending in the fore-and-aft direction, in which the pivot pin 21 of the extension beam 20, which can rotate between two positions, an extended position and a folded position, relative to the axle beam 12, is perpendicular to the vertical direction.
Therefore, unlike when the pivot pin 21 faces vertically, interference with the side frame 131 due to the pivot pin 21 rising up is suppressed, making it possible to smoothly expand and contract the traveling device 13 having the side frame 131.

In addition, the axle beam 12 allows a portion of the extension beam 20 in the folded position to be stored in the storage area H, so that when the vehicle body width is contracted, the extension beam 20 can be stored inward, making it possible to contract the lower running body 1 into a smaller size.
In particular, since the extension beam main body 22 is stored in the storage area H, the main portion of the extension beam 20 is stored, making it possible to more effectively shrink the lower traveling body 1 into a compact size.

In addition, when the extension beam 20 is in the extended position, it has a contact surface member 24 that can abut from below in a vertical direction against the side frame 131. As a result, the contact surface member 24 is able to support the upper plate 135c of the fitting portion 135 from below, making it possible to maintain the stability of the lower running body 1 even when a load is applied to the vehicle frame 11.
In addition, since the contact surface member 24 is detachable from the extension beam 20, the extension beam 20 can be easily stored, and the lower running body 1 can be easily contracted to a smaller size.

Furthermore, the contact surface member 24 has a convex member 241 and an abutment member 242, and the abutment member 242 has a greater width in the front-rear direction than the convex member 241. Therefore, even if a large pressing force is applied from the convex member 241 toward the axle beam 12 due to a load being applied to the body frame 11, the abutment member 242 can distribute this force, thereby reducing the burden on the members.
In addition, since the convex member 241 and the abutment member 242 are separate bodies, it is possible to increase the degree of freedom in designing the abutment surface member 24. For example, it is possible to realize a structure that is easy to store while increasing strength, such as by forming both members into a plate shape.

In addition, the storage sections 136, 137 for the convex member 241 and the abutment member 242 of the contact surface member 24 removed from the extension beam 20 and the storage section 138 for the fixing pin 25 are provided on the side of the side frame 131, so that the free space around the side frame 131 can be effectively utilized. Furthermore, when expanding the width of the vehicle body, the convex member 241, the abutment member 242, and the fixing pin 25 can be prepared near the fitting section 135, which improves workability.

[Addition of interlocking mechanism]
Figure 7 is a side view when the interlocking mechanism 15 is provided on the traveling device 13, Figure 8 is a cross-sectional view of the area around the extension beam 20 showing the interlocking mechanism 15 when the extension beam 20 is in the extended position, and Figure 9 is a cross-sectional view of the area around the extension beam 20 showing the interlocking mechanism 15 when the extension beam 20 is in the folded position.
As shown in these figures, the running device 13 of the lower running body 1 may be provided with an interlocking mechanism 15 that rotates the extension beam 20 toward the folded position as the side frame 131 moves inward in the width direction relative to the body frame 11 (moving toward a contracted state of the body width).

The interlocking mechanism 15 includes a link member 151 that interlocks the extension beam main body 22 and the extension beam connecting portion 23 of the extension beam 20 with the movement of the side frame 131, a first connecting portion 152 that connects one end of the link member 151 to the fitting portion 135, and a second connecting portion 153 that connects the other end of the link member 151 to the extension beam connecting portion 23.
As shown in FIG. 7 , the interlocking mechanism 15 is provided inside the fitting portion 135 of the side frame 131 .

The first connecting portion 152 is a bracket provided on the lower surface of the upper plate 135c of the fitting portion 135, and is rotatably connected to one end of the link member 151 via a support shaft 154 along the front-rear direction.
The second connecting portion 153 is a bracket provided on the surface that becomes the upper surface of the tip of the extension beam connecting portion 23 when the extension beam 20 is in the extended position, and is rotatably connected to the other end of the link member 151 via a support shaft 155 that runs along the fore-and-aft direction.
The other end of the link member 151 is connected to a support shaft 155 of the second connecting portion 153 via a long hole 151 a along the longitudinal direction of the link member 151 .

In the above configuration, when the side frame 131 of the traveling device 13 moves relative to the body frame 11 to a state where the vehicle width is contracted, the state in FIG. 8 transitions to the state in FIG. 9. That is, as the side frame 131 moves, the extension beam main body 22 and the extension beam connecting portion 23 of the extension beam 20 are pulled by the link member 151 and rotate to the folded position.

Furthermore, when the side frames 131 of the traveling device 13 move relative to the body frame 11 to the expanded state of the vehicle body width, the state transitions from that shown in Fig. 9 to that shown in Fig. 8. That is, as the side frames 131 move, the extension beam main body 22 and the extension beam connecting portion 23 of the extension beam 20 are pushed by the link members 151 and rotate to the extended positions.
The interlocking mechanism 15 makes it possible to reduce the workload during the expansion and contraction operation of the traveling device 13.

The long hole 151a of the link member 151 is for absorbing the surplus movement amount when the movement amount of the side frame 131 is excessive with respect to the movement amount between the folded position and the extended position of the extension beam 20. Therefore, when no surplus movement amount occurs, the other end of the link member 151 and the support shaft 155 of the second connecting portion 153 may be connected by a round hole.
Moreover, for greater flexibility, the first connecting portion 152 and the second connecting portion 153 may be connected by a spring.

The configuration of the interlocking mechanism 15 shown is merely an example, and any configuration capable of interlocking the movement of the side frame 131 and the rotational movement of the extension beam 20 can be used.
For example, the interlocking mechanism may be a mechanism that uses a rack and pinion or other gears to convert the linear movement of the side frame 131 into a rotational movement and transmit the rotational movement to the extension beam 20 .
In addition, a hydraulic mechanism, a motor, or another actuator serving as a driving source may be used to impart a rotational motion to the extension beam 20 in conjunction with the movement of the side frame 131.

[Adding side weights]
FIG. 10 is a side view of the traveling device 13 when a side weight 16 is provided as a weight member.
The weight member is a weight that is heavier than the side frame. For example, the weight member may be made of a metal with high density, such as lead. It may also be a member similar to the weight 14 or a box-shaped member in which a separate member (not limited to a solid, but may also be a liquid) is enclosed.
As shown in the figure, the lower traveling body 1 may be equipped with a side weight 16 instead of or in addition to the weight 14. Although only the left side weight 16 is illustrated in Fig. 10, a side weight 16 is also provided on the right side of the lower traveling body 1.

The side weight 16 has a weight body 161 and a locking hook 162 for attaching the weight body 161 to the outer surface of the side frame 131 of the undercarriage 1 in the vehicle width direction.
The two locking hooks 162 are provided side by side in the front-rear direction on the side surface of the weight body 161 facing the side frame 131. Each locking hook 162 has a lockable portion that is recessed upward.
Meanwhile, a support shaft 139b supported along the front-rear direction by a bracket 139a is provided on the outer surface of the side frame 131, and a locked portion of a locking hook 162 is locked to the support shaft 139b.
Furthermore, the weight body 161 is provided with a connecting screw shaft 163 extending towards the side frame 131, and a fixing nut 139c into which the connecting screw shaft 163 can be screwed is attached at a corresponding position on the side frame 131. The connection between the connecting screw shaft 163 and the fixing nut 139c makes it possible to maintain the locking state between the locking hook 162 and the support shaft 139b.

The connection structure of the side weight 16 to the side frame 131 is merely one example, and any well-known connection structure may be used.
In this way, by making it possible to equip the lower running body 1 with the side weights 16, the weight of the lower running body 1 can be increased, and the stability of operation during work can be improved.
Furthermore, since the side weights 16 are provided on the side portions of the side frames 131, it is possible to effectively utilize the empty space around the side frames 131. In particular, by providing the side weights 16 in the central portion of the two axle beams 12, this empty space can be utilized more effectively.
In addition, if the extension beam 20 is not an assembly part, the storage sections 136, 137, and 138 for the side weights 16 will not be necessary, and it will be possible to mount the side weights 16 so that they are stored extra inward.
Further, although the side weights 16 are exemplified as being removable, they may not be removable and may remain installed at all times.

[others]
The details shown in the above embodiment of the invention can be modified as appropriate without departing from the spirit of the invention.
For example, in the above embodiment, an example was given of the case where the pivot pin 21 of the extension beam 20 is parallel to the fore-and-aft direction, but as long as the extension beam 20 in the extended position extends generally in the extension direction of the axle beam 12, it does not have to be strictly parallel to the fore-and-aft direction.
For example, the pivot pin 21 may be inclined within a certain range with respect to the strict longitudinal direction of the vehicle body. If the pivot pin 21 is inclined too much in the width direction or vertical direction with respect to the longitudinal direction, the extension beam 20 cannot be inserted into the side frame 131 because it interferes with the inner wall of the fitting portion 135 of the side frame 131. Therefore, the inclination to the extent that the extension beam 20 can be inserted is included in the longitudinal direction mentioned for the extension beam 20 in the embodiment of the invention.
For example, in the direction in which the extension beam 20 and the side frame 131 are connected (vertical direction: the direction in which the connecting pin 25 is inserted), the gap between the extension beam 20 and the side frame 135 is small to prevent the connection from rattling. Therefore, an inclination of 5 degrees or less in the vertical direction relative to the front-rear direction is allowed without affecting the connection. In other words, an inclination of 5 degrees or less in the vertical direction relative to the front-rear direction is included in the front-rear direction described above. However, it is preferably 2 degrees or less, and more preferably 1 degree or less. On the other hand, in the width direction, which is not the direction in which the extension beam and the side frame are connected, there is a gap between the inner wall of the fitting portion 135 of the side frame 131 and the extension beam to facilitate insertion, so an inclination of up to 15 degrees is allowed without affecting the connection. In other words, an inclination of 15 degrees or less in the width direction relative to the front-rear direction is included in the front-rear direction. However, it is preferably 10 degrees or less, and more preferably 2 degrees or less.

In addition, in the above embodiment, a crawler crane is used as an example of a work machine, but the present invention is not limited to this and can be applied to hydraulic excavators and various other work machines in which the side frames expand and contract relative to the vehicle frame.

1 Lower traveling body 11 Vehicle body frame 12 Axle beam 124 Partition wall 13 Traveling device 131 Side frame 135 Fitting portion 135a Lower plate 135b Connection hole 135c Upper plate 136, 137, 138 Storage portion 14 Weight 15 Interlocking mechanism 151 Link member 151a Long hole 152 First connecting portion 153 Second connecting portion 16 Side weight 161 Weight body 162 Locking hook 163 Connection screw shaft 20 Extension beam 21 Rotation pin 22 Extension beam body portion 23 Extension beam connection portion 231 Insertion hole 24 Contact surface member 241 Convex member 241a Extension portion 241b Extension portion 241c Opposing surface 242 Contact member 242a Recess 25 Fixing pin 26 Stopper pin H Storage area

Claims (7)

The vehicle frame,
side frames arranged on both sides of the vehicle body frame in a width direction;
an axle beam extending in the width direction from the vehicle body frame and inserted into the side frame;
an extension beam that can be rotated about a pivot pin between two positions, an extended position and a folded position, relative to the axle beam;
A work machine having
The pivot pin has a support axis extending in the front-rear direction. The work machine of claim 1 , wherein the axle beam is capable of storing at least a portion of the extension beam in the folded position. The work machine according to claim 1 or 2, wherein the extension beam has a contact surface member that is capable of contacting the side frame from below when the extension beam is in the extended position. The work machine according to claim 3 , wherein the contact surface member is removable from the extension beam. The work machine according to claim 4 , wherein the contact surface member detached from the extension beam is attachable to the side frame. The work machine according to claim 1 , further comprising an interlocking mechanism that rotates the extension beam toward the folded position in accordance with inward movement of the side frames relative to the vehicle body frame in the width direction. The work machine according to any one of claims 1 to 6, wherein a weight member can be attached to the side frame when the extension beam is in the folded position.

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