JP5119220B2 - Swivel frame - Google Patents

Description

  The present invention relates to a turning frame of a traveling crane having a lattice boom.

  In a traveling crane that supports the lattice boom on the front side, the vehicle width may be restricted. And in the conventional traveling crane, in order to keep a vehicle width in the range of a regulation value, the following measures are taken, for example.

  First, the cab and the power unit, which are arranged separately on the left and right deck frames (see the left frame 12a and the right frame 12b in FIG. 2) of the swivel body, Are arranged side by side. Furthermore, in order to maintain the left and right weight balance of the revolving structure, the center position of the lattice boom is offset (shifted) in the vehicle width direction (left-right direction) with respect to the turning center position. Patent Document 1 discloses an example of a crawler crane in which a boom position is offset.

JP 2009-161278 A

  Usually, in a traveling crane, two boom feet are supported by a support body including a front wall and two side walls of a revolving frame. The load applied to the swing frame by the boom foot is supported by the swing bearing portion.

Further, when the boom position is offset in the vehicle width direction, the position of one boom foot is far away from the swing bearing compared to the position of the other boom foot. Here, of the pair of side plates that support the two boom feet, a side wall far from the turning center of the turning bearing is referred to as a “far wall”.
In this case, among the corner regions between the support and the slewing bearing of the bottom plate, the far wall region (see the corner region H with dot hatching in FIGS. 2, 3 and 6) is the opposite side. It bends greatly compared to the area. As a result, the lateral deflection applied to the boom is increased.

  In order to suppress such bending of the bottom plate, conventionally, (i) increasing the thickness of the entire corner region (region H in the figure) on the far wall side, (ii) box-like on the far wall and the front wall The rigidity of the swivel frame is increased by attaching a support. However, when such a method is adopted, the weight of the vehicle is significantly increased. Since the traveling crane is strictly regulated in terms of weight, it is desirable that the swing frame can be reinforced without significantly increasing the weight.

(Task)
Therefore, the problem to be solved by the present invention is to effectively reinforce the turning frame without significantly increasing the weight and reduce the lateral deflection of the lattice boom when the boom position of the traveling crane is offset. is there.

(1) In order to solve the above-described problems, a turning frame according to the present invention is installed on a lower traveling body of a traveling crane via a turning bearing, and supports a boom foot of a lattice boom on the front side.
The swivel frame includes a bottom plate and a support body that is installed on the bottom plate and supports the lattice boom, and the support bodies are disposed so as to sandwich the lattice boom and are arranged in a pair of left and right parallel to the front-rear direction. And a front wall disposed on the front side of the bottom plate and parallel to the vertical direction and perpendicular to the pair of side walls.
Each of the side walls supports the boom foot of the lattice boom in a state where the lattice boom can be raised and lowered, and the center position of the lattice boom is offset in the vehicle width direction with respect to the position of the swing center of the swing bearing.
Of the pair of side walls, the far wall, which is the side wall farther from the turning center, is closest to (i) the support position of the boom foot on the far wall and (ii) the outer peripheral line of the turning bearing. It is reinforced along a straight line connecting the position.

In this configuration, in the traveling crane in which the boom center position is offset in the vehicle width direction with respect to the turning center, the support position of the boom foot and the turning bearing of the far wall (the side wall far from the turning center) The vicinity of the outer peripheral line is reinforced linearly. Therefore, it is possible to efficiently suppress the bending of the bottom plate on the far wall side with the minimum reinforcement of the far wall without reinforcing the entire far wall.
Therefore, according to this configuration, it is possible to effectively reinforce the turning frame without significantly increasing the weight and to reduce the lateral deflection of the lattice boom.

  The “traveling crane” includes both a wheel crane and a crawler crane (an endless track vehicle). The subject of the present invention is a traveling crane that supports a boom on the front side of the vehicle.

The boom foot support system may be a system in which a shaft attached to the boom foot is inserted into a through hole provided in the side wall, and conversely, a shaft formed on the side wall is a boom foot. It may be a method of being inserted into the through-hole formed in the. Moreover, the system which a through-hole is formed in both a boom foot and a side wall, and a rotating shaft is inserted in these through-holes may be sufficient.
The “boom center position” is the center position of the boom in the width direction.

  The above-mentioned “peripheral line of the slewing bearing” means the outermost peripheral line of the part attached to the slewing frame in the slewing bearing device. Therefore, when the outer race (outer ring) is attached to the revolving frame, the outer race's outer circumference corresponds to the “outer circumference of the revolving bearing” and the inner race (inner ring) is attached to the revolving frame. In the case of the outer race, the outer circumference of the inner race corresponds to the “outer circumference of the swing bearing”.

The above-mentioned “reinforcement” includes an increase in plate thickness (of the target portion), attachment of reinforcing bone members (ribs) to the target portion, and the like.
“Reinforcing along a straight line” means that the vicinity of the straight line is reinforced.
Moreover, either side may be reinforced about each of a side wall and a front wall, and both surfaces may be reinforced.

  (2) In the turning frame of (1) according to the present invention, the front wall is (i) a position closest to a support position of the boom foot on the far wall, and (ii) an outer peripheral line of the turning bearing. It may be reinforced along a straight line connecting the nearest position.

In this configuration, the position of the front wall closest to the far foot boom foot support position and the vicinity of the outer peripheral line of the swivel bearing are reinforced linearly. Therefore, it is possible to efficiently suppress the bending of the bottom plate on the far wall side with the minimum reinforcement of the front wall without reinforcing the entire front wall.
Therefore, according to this configuration, it is possible to effectively reinforce the turning frame without significantly increasing the weight and to reduce the lateral deflection of the lattice boom.

  (3) The turning frame of (2) according to the present invention may further include a reinforcing plate fixed to the reinforcing portion of the far wall, the reinforcing portion of the front wall, and the bottom plate. Good.

  In this configuration, the reinforcing plate is fixed to three locations of the far wall reinforcing portion, the front wall reinforcing portion, and the bottom plate. Therefore, the turning frame is further reinforced by the reinforcing plate, the far wall, and the front wall, and the bending of the corner region (region H in FIG. 2) of the far plate on the far wall side is further suppressed. Further, since only one plate is added, the weight does not increase significantly.

  In addition, the above-mentioned “fixing” method includes, for example, a method of inserting one convex portion into the other concave portion, a method of integrally forming an object to be fixed and a reinforcing plate, in addition to welding, adhesion, and the like. It is.

(4) In order to solve the above-described problems, the turning frame according to the present invention is installed on the lower traveling body of the traveling crane via the turning bearing, and supports the boom foot of the lattice boom on the front side.
The swivel frame includes a bottom plate and a support body that is installed on the bottom plate and supports the lattice boom, and the support bodies are disposed so as to sandwich the lattice boom and are arranged in a pair of left and right parallel to the front-rear direction. And a front wall disposed on the front side of the bottom plate and parallel to the vertical direction and perpendicular to the pair of side walls.
Each of the side walls supports the boom foot of the lattice boom in a state where the lattice boom can be raised and lowered, and the center position of the lattice boom is offset in the vehicle width direction with respect to the position of the swing center of the swing bearing.
And when the side wall far from the turning center is the far wall of the pair of side walls, the front wall is (i) a position closest to the support position of the boom foot on the far wall; ii) It is reinforced along a straight line connecting the position closest to the outer peripheral line of the slewing bearing.

In this configuration, in a traveling crane in which the boom center position is offset in the vehicle width direction with respect to the turning center, the position closest to the boom foot support position on the far wall and the vicinity of the outer periphery of the turning bearing in the front wall Are reinforced linearly. Therefore, it is possible to efficiently suppress the bending of the bottom plate on the far wall side with the minimum reinforcement of the front wall without reinforcing the entire front wall.
Therefore, according to this configuration, it is possible to effectively reinforce the turning frame without significantly increasing the weight and to reduce the lateral deflection of the lattice boom.

  The “traveling crane”, “lattice boom”, “boom foot support method”, “slewing bearing outer circumference”, “boom center position”, and “reinforcement” in this configuration are the same as in (1) above. Therefore, the description is omitted.

It is a side view of the crawler crane concerning a 1st embodiment of the present invention. It is a top view which shows a turning frame etc. It is an upper surface enlarged view of an outer race and a turning frame. It is a perspective view of a turning frame. FIG. 4 is an A-A ′ perspective sectional view of FIGS. 2 and 3. FIG. 6 is a perspective cross-sectional view for explaining a reinforcing portion in FIG. 5. It is a side view of the crawler crane which concerns on 2nd Embodiment of this invention. (A) is a perspective view of the reinforcement board of FIG. 7, (b) is a perspective view of the reinforcement board which concerns on a modification.

(First embodiment)
The first embodiment of the present invention will be described below. In the following description and drawings, the vehicle front-rear direction is referred to as the front-rear direction K (see the arrow K direction in the figure). Further, with respect to the front-rear direction K, the front side is K1 and the rear side is K2 (see symbols K1 and K2 in the figure). Further, the left-right direction of the vehicle is referred to as a vehicle width direction W (see the arrow W direction in the figure). Further, unless otherwise specified, in the figure, a broken line is a hidden line indicating the shape of a hidden portion, and a two-dot chain line is an imaginary line.

  As shown in FIG. 1, the crawler crane 1 is a traveling crane having a lower traveling body 10, a swing bearing 20, and an upper swing body 11. The lower traveling body 10 is an endless track vehicle. The upper swing body 11 is installed on the lower traveling body 10 via a swing bearing 20, and swings about a vertically extending axis as a rotation axis.

(Slewing bearing)
The slewing bearing 20 includes an outer race (outer ring) 21 and an inner race (inner ring) 22. The swing bearing 20 is sandwiched between the lower traveling body 10 and the upper swing body 11.

  The inner race 22 is fixed to the upper surface of the lower traveling body 10 using bolts. The outer race 21 is fixed to the lower surface of the turning frame 40 of the upper turning body 11 using bolts. Then, the inner race 22 is accommodated inside the outer race 21. Further, a gear of an output shaft of a motor (not shown) fixed to the upper swing body 11 meshes with a gear formed inside the inner race 22. As the motor rotates, the outer race 21 rotates around the inner race 22. As a result, the upper turning body 11 turns on the lower traveling body 10.

(Upper turning body)
The upper swing body 11 includes a swing frame 40, two deck frames (left frame 12a and right frame 12b), a lattice boom 30, a cab 51, a winding winch (not shown), a hook 59h, and a gantry 54 (see FIG. 1 and FIG. 2). The revolving frame 40 includes a bottom plate 41 and a support body 42.

  The swivel frame 40 and the two deck frames support a later-described device mounted on the upper swivel body 11. Further, the left frame 12a and the right frame 12b are respectively fixed to the bottom plate 41 of the turning frame 40 with bolts. Therefore, the two deck frames rotate with the rotation of the turning frame 40.

  On the right frame 12b, a cab 51, a power unit, and the like are arranged in the front-rear direction K. The cab 51 functions as a cockpit during crane work. The power unit includes an engine, a hydraulic pump, and the like. Further, a pump, a tank, and the like are arranged in the front-rear direction K on the left frame 12a. In FIG. 2, the installation on the deck frame is omitted.

Among the objects installed on the deck frame, the cab 51 and the power unit having a relatively wide width are arranged on the right frame 12b. Accordingly, the width of the right frame 12b is wider than the width of the left frame 12a. As a result, the width of the crawler crane 1 is narrower than when the cab 51 and the power unit are separately installed on the left and right deck frames.
In order to maintain the right and left weight balance, the turning center G of the slewing bearing 20 (see the point G in the figure) is closer to the right frame 12b than the center of the slewing frame 40 (see FIG. 2).

  The lattice boom 30 is attached to the revolving frame 40 in a state where it can be raised and lowered. At the lower end of the lattice boom 30, two boom feet 30f are arranged side by side in the vehicle width direction W. Each boom foot 30f is composed of two plates sandwiching a side wall (described later) of the support 42. The lattice boom 30 is raised and lowered with two boom foot pins 30p (see FIG. 2) as the central axis. Each boom foot may be a single plate.

  A boom point sheave 52s is attached to the tip of the lattice boom 30, and a hook 59h is suspended from the boom point sheave 52s. A hook sheave 59s is attached to the hook 59h.

  The winding winch is installed in the main body of the upper swing body 11. A tip of a winding wire rope 52r is attached to the winding winch. The hoisting wire rope 52r extends from the hoisting winch and is wound around both the boom point sheave 52s and the hook sheave 59s. Then, the hook 59h is moved up and down by controlling the hoisting winch.

  The gantry 54 is installed behind the main body of the upper swing body 11. The top of the gantry 54 and the tip of the lattice boom 30 are connected via a boom hoisting rope 56 and a boom guy line 58. A lower spreader 55 is attached to the top of the gantry 54, and an upper spreader 57 is connected to the end of the boom guy line 58. The boom hoisting rope 56 extends from a boom hoisting winch (not shown) provided in the main body of the upper swing body 11, and is wound around both the upper spreader 57 and the lower spreader 55. And the raising / lowering operation | movement of the lattice boom 30 is performed by controlling the boom raising / lowering winch.

  As described above, the cab 51 and the power unit having a large vehicle width are installed on the right frame 12b. In the crawler crane 1, the center position of the lattice boom 30 is offset in the vehicle width direction W with respect to the position of the turning center G of the slewing bearing 20 (see point G in the figure). Thus, the left and right weight balance of the crawler crane 1 is maintained by offsetting the boom center position from the turning center position.

The offset of the boom position will be described with reference to FIGS. A line passing through the turning center G of the slewing bearing 20 and extending in the front-rear direction K is defined as a center line RC (swivel center line; refer to a one-dot chain line RC in the figure). Further, the center line (center line in the width direction) of the lattice boom 30 is defined as a center line BC (boom center line; see the dashed line BC in the figure). In this case, in the top view, the center line BC is shifted from the center line RC by δ (δ: offset amount) in the vehicle width direction W (see FIG. 2). Therefore, of the corner regions located outside the slewing bearing 20 and located inside the support 42, the region near the far wall 43b (the corner region H with dot hatching in the figure) is the other corner region. Bigger than. In the present embodiment, the area of the other corner region (side wall 43a side) is zero.
The corner region H is surrounded by the far wall 43b, the front wall 44, and the outer race 21 in a top view (FIGS. 2 and 3).

  FIG. 2 shows only the turning frame 40, the two deck frames, and the outer race 21. Further, FIG. 4 does not show the swivel bearing.

(Swivel frame)
Next, details of the turning frame 40 will be described. The revolving frame 40 is made of metal, and the revolving frame 40 includes a bottom plate 41 and a support body 42. The bottom plate 41 is a horizontal plate extending in the front-rear direction K, and the support 42 is attached on the bottom plate 41.

  The turning frame 40 is installed on the lower traveling body 10 via the turning bearing 20. Moreover, the turning frame 40 supports the two boom feet 30f of the lattice boom 30 on the vehicle front side (see FIG. 1).

(Support)
The support 42 supports the lattice boom 30 and includes a pair of left and right side walls (side walls 43a and 43b) and a front wall 44 (see FIGS. 2 to 6). The support body 42 is fixed on the bottom plate 41. In addition, regarding the fixing method of the support body 42 and the baseplate 41, you may integrally mold the support body 42 and the baseplate 41 other than welding or adhesion | attachment.

  A pair of side walls have the same shape, and these are arrange | positioned so that the lattice boom 30 may be pinched | interposed. Each side wall supports two boom feet 30f of the lattice boom 30 in a state in which the lattice boom 30 can be raised and lowered. Each side wall is parallel to the front-rear direction K and parallel to the vertical direction (see FIGS. 2 to 4).

  Each side wall is formed with a protruding portion 43t that protrudes forward and obliquely upward (see FIGS. 4 to 6). Further, a through hole 43h is formed in the protrusion 43t. The through hole 43h penetrates the side wall along the vehicle width direction W.

  In addition, each boom foot 30f is formed with a through hole, and the boom foot pin 30p, which is a rotating shaft, penetrates both the boom foot 30f and the side wall 43b. Inserted into the hole. Thereby, the two boom feet 30f are supported by the support body 42 in a state in which the lattice boom 30 can be raised and lowered (see FIG. 2).

  In the pair of side walls, the side wall 43 a is closer to the turning center G of the turning bearing 20 than the side wall 43 b. That is, the shortest distance between the side wall 43a and the turning center G is shorter than the shortest distance between the side wall 43b and the turning center G (see FIGS. 2 and 3). In the following description, of the pair of side walls, the side wall 43b far from the turning center is referred to as a “far wall”.

  The front wall 44 is disposed on the front side of the bottom plate 41, is parallel to the vertical direction, and is disposed perpendicular to the pair of side walls. The front wall 44 is a rectangular plate member and is fixed to the two side walls and the bottom plate 41.

(About reinforcement)
Next, reinforcement of the side wall (far wall) 43b and the front wall 44 will be described. 5 is a cross-sectional view taken along the line AA ′ of FIGS. 2 and 3, and the range shown in FIG. 5 corresponds to a range B surrounded by a broken-line square in FIGS.

  A reinforcing bar 46 is attached to the inner surface of the far wall 43b (the surface facing the side wall 43a) as a reinforcing bone member (see FIGS. 4 and 5). The reinforcing bar 46 is made of metal and is formed in a substantially semi-cylindrical shape and linearly. The reinforcing bar 46 is attached along a straight line 46L that connects the position C and the position D in the drawing (see FIGS. 2, 5, and 6). FIG. 6 is an explanatory diagram, and the reinforcing bar 46 is omitted in FIG. 6. Also in FIGS. 2 and 3, the reinforcing bar 46 is omitted.

The position C in FIGS. 2, 3 and 6 corresponds to the support position of the boom foot 30f on the far wall 43b, that is, the position of the through hole 43h.
2, 3, and 6 corresponds to the position closest to the outer peripheral line of the slewing bearing 20 (that is, the outer peripheral line of the outer race 21) on the far wall 43 b.

  The reinforcing bar 46 is provided to reinforce the straight line connecting the position C and the position D of the far wall 43b. By this reinforcement, the bending of the corner region H of the bottom plate 41 is suppressed.

  Further, a reinforcing bar 47 is attached to the front surface of the front wall 44 as a reinforcing bone member (see FIGS. 4 and 5). The reinforcing bar 47 is made of metal and is formed in a substantially semi-cylindrical shape and linearly. The reinforcing bar 47 is attached along a straight line 47L that connects the position E and the position F in the figure (see FIGS. 2, 5, and 6). FIG. 6 is an explanatory diagram, and the reinforcing bar 47 is omitted in FIG. 6. Also in FIG. 2 and FIG. 3, the reinforcing bar 47 is omitted.

2, 3, and 6 corresponds to a position on the front wall 44 that is closest to the through hole 43 h (the support position C of the boom foot 30 f on the far wall 43 b).
2, 3, and 6 corresponds to a position on the front wall 44 that is closest to the outer peripheral line of the slewing bearing 20 (that is, the outer peripheral line of the outer race 21).

  The reinforcing bar 47 is provided to reinforce the straight line connecting the position E and the position F of the front wall 44. Also by this reinforcement, the bending of the corner region H of the bottom plate 41 is suppressed.

  In addition, the broken-line circle drawn at the position C, the position D, the position E, and the position F in the drawing indicates a range (extended) corresponding to each position. Also, the points inside the broken-line circle at positions C, D, E, and F in the figure indicate the center points of the respective positions.

  Thus, in the revolving frame 40, each of the far wall 43b and the front wall 44 provided facing the corner region H is reinforced along the transmission direction of the load from the lattice boom 30. Therefore, when the load of the lattice boom 30 acts on the support body 42, the bending of the far wall 43b and the front wall 44 is suppressed. As a result, since the bending of the corner region H of the bottom plate 41 is suppressed, the lateral deflection of the lattice boom 30 is reduced.

(effect)
Next, effects obtained by the turning frame 40 according to the present embodiment will be described. The turning frame 40 is installed on the lower traveling body 10 of the traveling crane via the turning bearing 20, and supports the two boom feet 30f of the lattice boom 30 on the front side.
The swivel frame 40 includes a bottom plate 41 and a support 42 that is installed on the bottom plate 41 and supports the lattice boom 30. The support 42 is disposed so as to sandwich the lattice boom 30. A pair of left and right side walls (side wall 43a, side wall 43b) parallel to each other, and a front wall 44 disposed on the front side of the bottom plate 41 and parallel to the vertical direction and perpendicular to the pair of side walls.
Each side wall supports the boom foot 30f of the lattice boom 30 in a state in which the lattice boom 30 can be raised and lowered, and the center position of the lattice boom 30 is offset in the vehicle width direction W with respect to the position of the turning center G of the turning bearing 20. Yes.
Of the pair of side walls, the far wall 43b, which is the side wall farther from the turning center G, is (i) a support position C (through hole 43h) of the boom foot 30f on the far wall 43b, and (ii) a turning bearing. It is reinforced along a straight line 46 </ b> L that connects the position D closest to the outer peripheral line of 20.

In this configuration, in the traveling crane in which the boom center position is offset in the vehicle width direction W with respect to the turning center G, the support position of the boom foot 30f in the far wall 43b (side wall far from the turning center G). And the vicinity of the outer peripheral line of the slewing bearing 20 are reinforced linearly. Therefore, the bending of the bottom plate 41 on the far wall 43b side (the bending of the corner region H) can be efficiently suppressed by the minimum reinforcement of the far wall 43b without reinforcing the entire far wall 43b.
Therefore, according to this configuration, the revolving frame 40 can be effectively reinforced and the lateral deflection of the lattice boom 30 can be reduced without significantly increasing the weight.

  Further, in the revolving frame 40, in addition to the reinforcement of the far wall 43b, the front wall 44 is (i) a position E closest to the boom foot support position C (through hole 43h) on the far wall 43b. (Ii) It is reinforced along a straight line 47L connecting the position F closest to the outer peripheral line of the slewing bearing 20.

In this configuration, the position of the front wall 44 closest to the boom foot support position of the far wall 43b and the vicinity of the outer peripheral line of the slewing bearing 20 are reinforced linearly. Therefore, the bending of the bottom plate 41 on the far wall 43b side can be efficiently suppressed by the minimum reinforcement of the front wall 44 without reinforcing the entire front wall 44.
Therefore, according to this configuration, the revolving frame 40 can be effectively reinforced and the lateral deflection of the lattice boom 30 can be reduced without significantly increasing the weight.

The turning frame 40 is installed on the lower traveling body 10 of the traveling crane via the turning bearing 20, and supports the two boom feet 30f of the lattice boom 30 on the front side.
The swivel frame 40 includes a bottom plate 41 and a support 42 that is installed on the bottom plate 41 and supports the lattice boom 30. The support 42 is disposed so as to sandwich the lattice boom 30. A pair of left and right side walls (side wall 43a, side wall 43b) parallel to each other, and a front wall 44 disposed on the front side of the bottom plate 41 and parallel to the vertical direction and perpendicular to the pair of side walls.
Each side wall supports the boom foot 30f of the lattice boom 30 in a state in which the lattice boom 30 can be raised and lowered, and the center position of the lattice boom 30 is offset in the vehicle width direction W with respect to the position of the turning center G of the turning bearing 20. Yes.
The front wall 44 is reinforced along a straight line 47L connecting (i) the position closest to the support position C of the boom foot 30f on the far wall 43b and (ii) the position closest to the outer circumferential line of the slewing bearing 20. Has been.

In this configuration, in the traveling crane in which the boom center position is offset in the vehicle width direction W with respect to the turning center G, the position closest to the boom foot support position of the far wall 43b in the front wall 44, and the turning bearing The vicinity of the outer peripheral line of 20 is reinforced linearly. Therefore, the bending of the bottom plate 41 on the far wall 43b side can be efficiently suppressed by the minimum reinforcement of the front wall 44 without reinforcing the entire front wall 44.
Therefore, according to this configuration, the revolving frame 40 can be effectively reinforced and the lateral deflection of the lattice boom 30 can be reduced without significantly increasing the weight.

(About differences in crane types)
In a crane described in Japanese Patent Laid-Open No. 2000-72384 (a crane that supports a telescopic boom on the rear side of the vehicle), the support position of the boom foot is greatly overhanging rearward from the swing bearing. In the technique of this publication, the overhang amount α is considerably larger than the offset amount δ of the boom center with respect to the turning center (α> 1.5δ). Therefore, in this crane, it is important to efficiently transmit the load acting on the swing frame to the swing bearing to improve the swing stability, and the lateral deflection generated in the boom is not a big problem.
On the other hand, in the crawler crane 1 (the crane that supports the lattice boom in the front of the vehicle), the overhang amount α (the portion of the portion that protrudes outside the swing bearing 20) of the through hole 43h (the support position of the boom foot 30f on the far wall 43b). (Length) is equal to the offset amount δ (see FIG. 2). And in such a crawler crane 1, compared with the crane of Unexamined-Japanese-Patent No. 2000-72384, when the boom position is offset to the vehicle width direction, the side deflection of a boom becomes a remarkable problem. That is, the present invention is preferably applied to a crane in which the overhang amount α is equal to or less than the offset amount δ (0.8δ <α <1.2δ).

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, about the part similar to said embodiment, the same code | symbol is attached | subjected to a figure and the description is abbreviate | omitted.
Hereinafter, a description will be given centering on differences from the first embodiment. In FIG. 7, the portions denoted by reference numerals 140 and 142 correspond to the portions denoted by reference numerals 40 and 42, respectively, in the first embodiment.

  The revolving frame 140 according to the present embodiment includes a reinforcing plate 45 in addition to the bottom plate 41 and the support body 142. The reinforcing plate 45 is made of metal. The reinforcing plate 45 is fixed to the reinforcing bar 46, the reinforcing bar 47, and the bottom plate 41 by welding. The reinforcing plate 45 is attached to the bottom plate 41 in an inclined state, and the angle formed by the bottom plate 41 and the reinforcing plate 45 is about 45 degrees.

  As shown in FIG. 8A, the reinforcing plate 45 is a quadrangular plate. The shape of the reinforcing plate may be a triangular plate as in the reinforcing plate 45m in FIG. The reinforcing plate may have other shapes.

(effect)
The effect obtained by this embodiment will be described. The swivel frame 140 includes a reinforcing bar 45 (a reinforcing part in the far wall 43 b), a reinforcing bar 47 (a reinforcing part in the front wall 44), and a reinforcing plate 45 fixed to the bottom plate 41.

  In this configuration, the reinforcing plate 45 is fixed to three locations of the reinforcing portion of the far wall 43b, the reinforcing portion of the front wall 44, and the bottom plate 41. Therefore, the turning frame is further reinforced by the reinforcing plate 45, the far wall 43b, and the front wall 44, and the bending of the corner region H of the bottom plate 41 is further suppressed. Further, since only one plate is added, the weight does not increase significantly.

(About other embodiments)
The embodiment of the present invention is not limited to the above embodiment. For example, in the above embodiment, both the side wall 43b and the front wall 44 are reinforced, but only the side wall (far wall) 43b may be reinforced. Further, only the front wall 44 may be reinforced.

  In the above embodiment, the side walls and the front wall are reinforced by attaching the reinforcing ribs (the reinforcing bar 46 and the reinforcing bar 47). However, these wall portions may be reinforced by increasing the plate thickness. . That is, such a rib may be formed integrally with the side wall (or front wall).

  In the above embodiment, the inner surface (the surface facing the other side wall 43a) is reinforced for the side wall (far wall) 43b, and the front surface is reinforced for the front wall 44. The opposite surface may be reinforced, or both surfaces may be reinforced.

  In the above embodiment, the boom center line BC is shifted to the left with respect to the turning center line RC. However, the boom center line BC may be shifted to the right with respect to the turning center line RC. That is, the width of the left frame may be wider than that of the right frame, and the cab 51 and the power unit may be arranged on the front and rear of the left frame.

  Moreover, the material of the reinforcement bar 46, the reinforcement bar 47, and the reinforcement board 45 is not restricted to a metal.

  The present invention can be used as a turning frame of a traveling crane having a lattice boom.

1 Crawler crane (traveling crane)
DESCRIPTION OF SYMBOLS 10 Lower traveling body 20 Slewing bearing 30 Lattice boom 30f Boom foot 40 Swivel frame 41 Bottom plate 42 Support body 43a Side wall 43b Side wall (far wall)
44 Front wall 45 Reinforcement plate

Claims (4)

A swing frame (40) installed on a lower traveling body (10) of a traveling crane via a swing bearing (20) and supporting a boom foot (30f) of a lattice boom (30) on the front side;
A bottom plate (41), and a support (42) installed on the bottom plate and supporting the lattice boom,
The support body is disposed so as to sandwich the lattice boom, and is provided on a pair of left and right side walls (43a, 43b) parallel to the front-rear direction and on the front side of the bottom plate, and is parallel to the vertical direction and perpendicular to the pair of side walls. A front wall (44),
Each of the side walls supports a boom foot of the lattice boom in a state where the lattice boom can be raised and lowered,
The center position of the lattice boom is offset in the vehicle width direction with respect to the position of the turning center of the turning bearing,
Of the pair of side walls, the far wall (43b), which is the side wall farther from the turning center, is (i) the position where the boom foot is supported on the far wall, and (ii) the outer peripheral line of the turning bearing. A swivel frame characterized by being reinforced along a straight line connecting the close position.   The front wall is reinforced along a straight line connecting (i) a position closest to the support position of the boom foot on the far wall and (ii) a position closest to the outer peripheral line of the slewing bearing. The revolving frame according to claim 1, wherein   The swivel frame according to claim 2, further comprising a reinforcing plate (45) fixed to the reinforcing portion on the far wall, the reinforcing portion on the front wall, and the bottom plate. A swing frame (40) installed on a lower traveling body (10) of a traveling crane via a swing bearing (20) and supporting a boom foot (30f) of a lattice boom (30) on the front side;
A bottom plate (41), and a support (42) installed on the bottom plate and supporting the lattice boom,
The support body is disposed so as to sandwich the lattice boom, and is provided on a pair of left and right side walls (43a, 43b) parallel to the front-rear direction and on the front side of the bottom plate, and is parallel to the vertical direction and perpendicular to the pair of side walls. A front wall (44),
Each of the side walls supports a boom foot of the lattice boom in a state where the lattice boom can be raised and lowered,
The center position of the lattice boom is offset in the vehicle width direction with respect to the position of the turning center of the turning bearing,
Of the pair of side walls, when the side wall far from the turning center is a far wall (43b),
The front wall is reinforced along a straight line connecting (i) a position closest to the support position of the boom foot on the far wall and (ii) a position closest to the outer peripheral line of the slewing bearing. A swivel frame characterized by

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