JP4157191B2 - Roughing jib back tension device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a back tension device for a luffing jib mounted on the tip of a telescopic boom of a crane having a telescopic boom, and more particularly to a structure of an air sheave block in the back tension device.
[0002]
[Prior art]
The luffing jib is mainly used when crane work is required at a high place and with a relatively large working radius. Usually, the luffing jib is attached to the tip of the telescopic boom so that it can be raised and lowered, and by a back tension device. The undulation angle is adjusted, and the posture is held at the required undulation angle. A hanging wire rope extending from the winch arranged on the swivel side supporting the telescopic boom is suspended from the top sheave provided at the tip of the luffing jib, and the required crane work is performed using this hanging wire rope. .
[0003]
In addition, the back tension device generally has an aerial sheave block connected to a jib support member that is pulled out from the distal end portion of the luffing jib to the telescopic boom side through a mast erected at the base end portion of the luffing jib. Yes. A back tension wire rope fed from a winch arranged on the swivel side is hung on the aerial sheave block, and then hung on a fixed sheave block that is swingably connected to the base end side of the base boom. A back tension wire is wound around the aerial sheave block and the fixed sheave block so as to have a predetermined multiplication number, and is connected to the fixed sheave block.
Then, by adjusting the undulation angle of the luffing jib and holding the posture at a predetermined undulation angle through the jib support member by winding and unwinding the back tension wire rope by the winch arranged on the swivel base side. It has become.
[0004]
By the way, as described above, the back tension wire rope is used in a multi-stage state in order to reduce the rope tension. As a method for multi-stepping such a back tension wire rope, a method shown in FIG.
FIG. 5 is a view of the base boom 3b and the swivel base 2 from the back, and is connected to a winch 13 disposed on the swivel base 2 and a jib support member 6 pulled out to the telescopic boom 3 side via a mast. The arrangement of a movable aerial sheave block 14 and a fixed sheave block 16 that is swingably connected to the base end side of the base boom 3b is shown. The back tension wire 15 fed out from the winch 13 is hung on an air sheave block 14 having a plurality of sheaves, is hung on a fixed sheave block 16 having a plurality of sheaves, and further, the air sheave block has a predetermined multiplication number. 14 and the fixed sheave block 16 are wound around, and the tip is connected to the connecting portion 19 of the fixed sheave block.
FIG. 6 is a wire rope hanging view in the state shown in FIG.
[0005]
As shown in FIG. 5, the drum 18 of the winch 13 is disposed so that the center in the width direction coincides with the center of the boom. This is because when the crane performs a boom operation or a jib operation other than the luffing jib operation, the wire rope fed out from the winch 13 is hung on the sheave at the substantially central portion in the boom width direction at the tip of the boom. This is because the above arrangement is necessary because of the relationship. As is well known, in order to wind up the wire wound around the drum 18 of the winch 13 in an orderly manner, it is necessary to make the fleet angle below a specified value. If the fleet angle exceeds the limit, the wire rope will wrap around the winch drum. Since the wire wound around the drum 18 is wound while moving left and right over the full width of the drum, it is convenient for the fleet angle to arrange the drum 18 so that the center in the width direction coincides with the center of the boom. is there. The jib support member 6 has been pulled out along the boom center, and the aerial sheave block 14 also moves along the boom center.
[0006]
However, when such a conventional method is adopted, there is a problem that the position where the back tension wire 15a fed out from the winch 13 hangs around the sheave groove of the aerial sheave block 14 deviates from the boom center by the sheave radius. there were. For this reason, as shown in FIG. 5, when the back tension wire rope 15a is first hooked on the right groove of the sheave of the aerial sheave block 14, it is drawn out from the left end of the drum 18 as a fleet angle. Will be in the worst state.
Therefore, it is necessary to determine the minimum distance between the air sheave block 14 and the fixed sheave block 16 during the luffing jib work on the basis of the worst state of the fleet angle. This led to the problem that the luffing jib work range was reduced. That is, when the luffing jib tilt angle is small when the telescopic boom is short, the distance between the aerial sheave block 14 and the fixed sheave block 16 is small, so the working range of the luffing jib is determined by the above-mentioned possible distance. is there. Further, if it is attempted to secure only the required range of the luffing jib work range, there is a problem that the width dimension of the winding portion of the drum 18 is limited.
The above problem does not become a big problem when the luffing jib is small and the winch drum width is narrow, but it becomes a significant problem when the mobile crane becomes very large and the winch drum width becomes wide.
[0007]
[Problems to be solved by the invention]
Therefore, the present invention proposes a luffing jib back tension device that can widen the luffing jib work range and can widen the winch drum width.
[0008]
[Means for Solving the Problems]
In the present invention, the following configuration is adopted as a specific means for solving such a problem.
[0009]
In the first invention of the present application, a luffing jib is mounted at the distal end of a telescopic boom attached to the base boom of the swivel base so that the base boom can be raised and lowered in a direction along the hoisting surface of the telescopic boom. The jib support member having one end connected to the leading end of the luffing jib is pulled out to the telescopic boom side through the mast erected at the base end of the luffing jib or the distal end of the telescopic boom, and the jib A support member is connected to an aerial sheave block made up of a plurality of sheaves, and a back tension wire rope fed out from a winch arranged on the swivel side is hung around the aerial sheave block, and swings toward the base end side of the base boom. The above-mentioned aerial sheave is hung around a fixed sheave block made up of a plurality of sheaves that are movably connected to each other so that a predetermined multiplication factor is obtained. The back tension wire is routed between the hook and the fixed sheave block, and then connected to an appropriate position near the fixed sheave block or an air sheave block, and the back tension wire rope is wound and unwound by the winch to In the luffing jib back tension device, the aerial sheave block has two sheaves that are substantially orthogonal to and parallel to the boom axis that is symmetrical to the boom axis. constituted by a plurality of sheaves having a central axis, to the back tension wire rope is unwound from the winch disposed on the swivel base side Kai hung from the groove located on the boom center side of the sheave of the aerial sheave block, the aerial sheave block Multiple sheaves of alternating It is characterized by being arranged overlapping.
[0011]
In the back tension device luffing jib according to the second invention in the first aspect of the present invention, the wire rope centers of the boom center side of the groove of the sheave of the aerial sheave block is arranged to be substantially in contact with the same plane It is characterized by being.
[0012]
In the present invention, the following effects can be obtained by adopting such a configuration. In the first invention of the present application, the aerial sheave block is configured by a plurality of sheaves having two sheave central axes that are positioned symmetrically with respect to the boom axis, substantially orthogonal to the boom axis, and parallel to the boom axis. Since the back tension wire rope drawn out from the winch placed on the base side is hung from the groove located on the boom center side of the sheave of the above-mentioned aerial sheave block, it touches the sheave of the aerial sheave block of the back tension wire drawn out from the winch Almost coincides with the boom axis. As a result, the left and right angles can be made substantially the same at the drum width end portion that is the maximum fleet angle for the fleet angle of the back tension wire that is fed out over the entire left and right of the winch drum width .
[0013]
Here, when a plurality of sheaves of the above-mentioned aerial sheave block are alternately overlapped, the back tension wires that are drawn out from the winch and run between the aerial sheave block and the fixed sheave block are spaced apart in the vertical direction. Can be secured.
[0014]
Further, as in the second invention of the present application, when the wire rope centers of the grooves on the boom center side of the plurality of sheaves of the aerial sheave block are arranged so as to be substantially in contact with the same plane, the back tension fed out from the winch to the aerial sheave block The fleet angle of the wire can be minimized.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on preferred embodiments. FIG. 1 shows a mobile crane with a luffing jib equipped with a back tension device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a vehicle as a traveling base, and 2 can turn on the vehicle 1. The base 3 (base boom 3b) is connected to the base 2 so that the base end (base boom 3b) can be raised and lowered in the vertical direction, and the telescopic boom 3 is provided with the telescopic boom 3. Is driven up and down by a hydraulic cylinder 10 for ups and downs.
[0016]
Further, reference numeral 5 denotes a luffing jib that is mounted on the distal end portion 3a of the telescopic boom so as to be raised and lowered.
As shown in FIG. 1, the luffing jib 5 has a base jib whose base end portion is connected to the front side of the boom tip end portion 3 a via a jib support 4 so as to be raised and lowered, and forms a base end portion of the luffing jib 5; The middle jib is connected to the tip of the base jib, and the top jib is connected to the tip of the middle jib to form the tip of the luffing jib 5 and has a top sheave for crane work at the tip. .
[0017]
In this embodiment, the luffing jib 5 is composed of the base jib, middle jib, and top jib as described above. However, the structure of the luffing jib 5 is not limited to this, and at least the base jib and top jib After that, one or more middle jibs are connected between the base jib and the top jib depending on conditions such as work radius or work lift required for work. Good.
[0018]
As shown in FIG. 1, the luffing jib 5 having such a configuration is attached to the distal end portion 3 a of the telescopic boom 3 via a jib support 4 so as to be raised and lowered. A jib support member 6 having one end connected to the distal end 5 a of the luffing jib 5 is connected to the telescopic boom 3 via a first mast 8 and a second mast 9 that are arranged upright at the base end of the luffing jib 5. Is pulled out to the upper surface side. The jib support member 6 includes a bending tension rod 11 that connects the tip of the first mast 8 and the tip of the second mast 9, and a tension rod 17 that is connected to the tip of the second mast. The tension rope 20 connected to the tension rod 17, the tension rope 21 connected to the tip of the first mast 8, and the tension rod 7 connected to the tension rope 21 provided corresponding to the middle jib. And a tension rod provided corresponding to the top jib and connecting the tip end portion of the top jib and the tension rod 7. Note that a pair of the jib support members 6 are arranged at a predetermined interval in the jib width direction.
[0019]
Further, an air sheave block 24 is connected to the tip ends of the tension ropes 20, 20 of the pair of jib support members 6, 6. Between the aerial sheave block 24 and the fixed sheave block 26 fixed to the base end portion of the base boom 3b, a main winding winch 13 ("winch" in the claims) disposed on the swivel base 2 side is provided. The main winding wire rope (corresponding to “back tension wire rope” in the claims) is extended in multiple stages. The back tension device is configured as described above, and the luffing jib 5 is appropriately driven up and down by winding and rewinding the main winding winch 13 and the main winding winch 13 is stopped and held so that the luffing jib 5 is required. The posture is maintained at the undulation angle position. The connection structure of the main winding wire rope 15 constituting a part of the back tension device is the gist of the present invention. Therefore, the connection structure and various components attached thereto will be described in detail later.
[0020]
Further, mast sheaves are provided at the tips of the first mast 8 and the second mast 9, respectively, and during the crane work using the luffing jib 5, the auxiliary winding winch 12 disposed on the swivel base 2 side. A supplementary wire rope 25 extending from the top sheave at the tip of the luffing jib 5 is suspended through the respective mast sheaves, and a required crane is used by using a hanging hook provided at the tip of the supplementary wire rope 25 Do work.
[0021]
FIG. 2 is a view taken in the direction of arrow A in FIG. 1 and shows a connection structure of the main wire rope 15 and various constituent members attached thereto.
Reference numeral 24 denotes an aerial sheave block, which is composed of a plurality of sheaves 29 and 30 having two sheave center shafts 27 and 28 that are positioned symmetrically with respect to the boom axis and that are substantially orthogonal to and parallel to the boom axis. . FIG. 3 is a BB arrow view of the air sheave 24. The left sheaves 29a and 29b and the right sheaves 30a and 30b are alternately overlapped with the boom axis of the aerial sheave block 24. In addition, the wire rope centers of the grooves on the boom center side of the plurality of sheaves of the aerial sheave block 24 are arranged so as to be substantially in contact with the same plane. Reference numeral 31 denotes a support for indicating the sheave center axes 27 and 28.
[0022]
The main winding wire rope 15 fed out from the drum 18 of the main winding winch 13 disposed on the swivel base 2 in FIG. 2 is wound around the right groove of the upper sheave 29a on the left side of the boom axis of the aerial sheave block 24. The folded sheave is looped around the uppermost sheave 33a of the fixed sheave block 26. Next, the air sheave block 24 is hung around the upper sheave 30a on the right side of the boom axis. Thus, the main winding wire rope wound so as to hang between the aerial sheave block 24 and the fixed sheave block 26 is finally connected to the connecting portion 39 of the fixed sheave block 26 via the rope end 38 and the load cell 37. Connected. FIG. 4 shows a wire rope hanging diagram of the back tension device.
A tension rope 20, which is a jib support member pulled out to the telescopic boom side, is connected to the connecting portion 36 at the tip of the air sheave block 24.
[0023]
As described above, the main winding wire rope 15 a drawn out from the drum 18 of the main winding winch 13 is wound around the central portion of the air sheave block 24. In other words, since it is hung around a portion that coincides with the boom axis, the maximum value of the fleet angle of the main winding wire rope that is fed out while being swung left and right over the full width of the drum can be made the same angle on the left and right. For this reason, the distance between the air sheave block and the fixed sheave block can be shortened with respect to the specified value of the same fleet angle.
[0024]
The above embodiment has been described by taking an example in which the sheave central axis of the aerial sheave block is composed of two, but it can also be implemented even if it is composed of three or more axes.
Moreover, since the width dimension orthogonal to the boom axis of the aerial sheave block is widened, the attachment width of the back tension wire can be widened. As a result, the rotation of the wire rope can be reduced, so that the air sheave block can be prevented from being inclined obliquely.
[0025]
【The invention's effect】
Since the luffing jib back tension device of the present invention can be made shorter in the distance between the aerial sheave block and the fixed sheave block than the conventional one, the working range of the luffing jib work can be reduced. Can be spread. Further, if the minimum distance between the conventional sheave block, the aerial sheave block, and the fixed sheave block is the same, the width of the winding portion of the drum can be increased.
[Brief description of the drawings]
FIG. 1 is an overall view showing a preferred embodiment of a luffing jib back tension device according to the present invention.
FIG. 2 is a view taken in the direction of arrow A in FIG.
FIG. 3 is a view taken in the direction of arrow B in FIG. 2;
FIG. 4 is a view showing the wire tension of the back tension device according to the present invention.
FIG. 5 is a view showing a conventional luffing jib back tension device.
FIG. 6 is a drawing showing a wire rope of a conventional back tension device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle 2 Turntable 3 Telescopic boom 3b Base boom 4 Jib support 5 Roughing jib 6 Jib support members 7, 11, 17 Tension rod 8 First mast 9 Second mast 20, 21 Tension rope 12 Supplementary winding winch 13 Main winding winch 14, 24 Air sheave block 15, 15a Main winding wire rope 16, 26 Fixed sheave block 18 Drum 25 Supplement winding wire rope 27, 28, 32 Sheave central shafts 29, 30, 33 Sheave 29a, 29b, 30a, 30b Sheave 31, 34 Support

Claims (2)

A luffing jib is mounted on the tip of a telescopic boom whose base end is attached to the base boom so that the base boom can be raised and lowered with respect to the swivel base. The jib support member having one end connected to the telescopic boom is pulled out to the telescopic boom side through a mast erected at the base end portion of the luffing jib or the distal end portion of the telescopic boom, and the jib support member is removed from a plurality of sheaves. After the back tension wire rope fed from the winch arranged on the swivel base side is hung around the aerial sheave block, it is connected to the base end side of the base boom so as to be swingable. It is hung around a fixed sheave block consisting of a plurality of sheaves. The back tension wire is hung between the blocks, connected to an appropriate position in the vicinity of the fixed sheave block or an aerial sheave block, and the luffing jib is raised and lowered by winding and unwinding the back tension wire rope with the winch. In the back tension device of the luffing jib designed to hold the posture in the undulating position,
The aerial sheave block is formed of a plurality of sheaves having two sheave central axes that are positioned symmetrically with respect to the boom axis, substantially orthogonal to the boom axis, and fed out from the winch disposed on the swivel base side. back tension wire rope to Kai over the groove located on the boom center side of the sheave of the aerial sheave blocks, back luffing jib, wherein a plurality of sheaves of the aerial sheave blocks are disposed overlapping alternately Tension device. 2. The luffing jib back tension device according to claim 1, wherein the wire rope centers of the grooves on the boom center side of the plurality of sheaves of the aerial sheave block are arranged so as to be substantially in contact with the same plane. Tension device.

Images