JP6586858B2 - Boom deflection prevention device - Google Patents

Description

  The present invention relates to an apparatus for preventing the bending of a boom mounted on a crane or other work vehicle, and more specifically, to a mechanism for canceling the bending of a boom during a suspended load operation.

  For example, a crane truck generally includes a boom and a load wire. The suspended wire is hung around a sheave provided at the tip of the boom and hangs down, and a hook is connected to the tip. The suspended load is transported as required by operating the boom and the suspended wire while being hung on the hook. At this time, an axial force and a bending moment act on the boom, and the boom is bent. Even if the boom is bent, there is no problem with the boom, but it is difficult to accurately control the boom posture. For this reason, a device for suppressing the bending of the boom has been conventionally provided (see, for example, Patent Document 1 and Patent Document 2).

JP 2011-121753 A JP 2010-202361 A

  FIG. 5 schematically shows the boom deflection preventing device disclosed in Patent Document 1. As shown in FIG. As shown in FIG. 1, the boom deflection preventing device 10 includes a post 13 erected at an intermediate portion of the boom 12, a winch 14 provided on the post 13, a tension wire 15, and a tension link 16. ing. The tension wire 15 is wound around the winch 14 so as to be freely drawn out, and is connected to the distal end portion of the boom 12 via a sheave 17 provided at the distal end portion of the post 13. The tension link 16 connects the post 13 and the swivel base 18. During the lifting work, the boom 12 is bent in the direction of gravity acting on the hanging load (the direction in which the boom 12 is raised and lowered). However, the deformation of the boom 12 is suppressed by the tension wire 15 connecting the post 13 and the boom 12, and the bending of the boom 12 is cancelled. When the boom 12 is expanded and contracted during the lifting operation, the winch 14 is operated and the length of the tension wire 15 is adjusted.

  In the boom bending prevention device 10, a tension wire 15 having a length sufficient to cope with expansion and contraction of the boom 12 must be wound around the winch 14 in advance. For this reason, the mechanism of the post 13 is complicated and the weight is large. Further, in order for the tension wire 15 to respond to the expansion and contraction of the boom 12, the operation of the winch 14 must be controlled while maintaining the tension generated in the tension wire 15, but this control is complicated and generally not easy. .

  FIG. 6 schematically shows a boom bending prevention device 20 disclosed in Patent Document 2. As shown in FIG. As shown in the figure, the deflection preventing device 20 does not include the post 13, the winch 14, the tension wire 15, and the tension link 16 (see FIG. 5). In this boom bending prevention device 20, the suspended wire 22 fed from the suspended load winch 21 is hung around a sheave 26 provided at the tip of the boom 12 and a sheave 23 provided on the swivel base 18 side. The suspension sheaves 24 and 25 provided at the tip of the boom 12 are wound around. That is, the hanging wire 22 is disposed on the back side of the boom 12, and the tension generated in the hanging wire 22 suppresses the bending of the boom 12.

  However, in this bend prevention device 20, a very long suspended load wire 22 is necessary, and the capacity and mechanism of the suspended load winch 21 are increased in size and weight. Moreover, since the hanging wire 22 is laid out along the back surface of the boom 12 as described above, there is also a problem that the effect of suppressing the bending of the boom 12 is low.

  The present invention has been made based on such a background, and an object of the present invention is to provide a boom deflection prevention device having a light weight and a simple structure that effectively suppresses the deflection of the boom during a lifting operation. .

  (1) In order to achieve the above object, a boom deflection preventing device according to one invention includes a swivel base, an extendable boom connected to the swivel base so as to be raised and lowered, a suspended load winch, and the suspended load winch. And is applied to a work vehicle having a suspended wire wound around a suspended sheave of a telescopic boom. The boom bending prevention device is provided on a back side of the telescopic boom, and has a post provided with a first tension sheave at a front end portion thereof; a second tension sheave disposed at a rear end side of the telescopic boom; A third tension sheave disposed opposite to the second tension sheave on the back side of the telescopic boom, and one end and the other end of the telescopic boom are respectively connected to the swivel base or the predetermined portion of the telescopic boom and the third sheave; And an intermediate portion including a back tension wire wound around the first tension sheave. The said load wire is previously wound around the said 2nd tension sheave and the 3rd tension sheave before being wound around the said load sheave.

  When crane work is performed by such a work vehicle, the telescopic boom is generally raised at a required angle and extended to a required length. The suspended wire drawn from the suspended load winch is wound around the suspended sheave and hangs down, and the load is suspended through the hook. In this state, an axial force and a bending moment act on the telescopic boom, and the telescopic boom bends so that its back side is convex. That is, a tensile stress is generated on the back surface of the telescopic boom.

  According to this invention, the suspended wire drawn out from the suspended load winch is wound around the second tension sheave and the third tension sheave in advance before being wound around the suspended load sheave. These second and third tension sheaves are disposed on the rear side of the tip of the telescopic boom. A back tension wire is disposed on the back side of the telescopic boom, and the back tension wire connects the third tension sheave and a predetermined position of the swivel base or the telescopic boom. An intermediate portion of the back tension wire is supported by the first tension sheave. Since the first tension sheave is provided at the tip of the post erected on the back side of the telescopic boom, there is a certain distance between the first tension sheave and the back surface. That is, the tip of the telescopic boom, the first tension sheave, and the predetermined position of the swivel base or the telescopic boom form a geometry that forms a virtual triangle by the back tension wire. By the way, since the load wire is wound around the second and third tension sheaves as described above, the tension of the load wire generated by the load operation becomes the tension of the back tension wire. Accordingly, the telescopic boom is bent by the suspended load operation (bending that the back side is convex), and at the same time, the back boom is bent by the tension of the back tension wire. These are offset and the bending of the telescopic boom is suppressed.

  Since the back tension wire has a triangular shape as described above, the bending moment acting on the telescopic boom (the bending moment in the direction in which the back side of the telescopic boom is concave) increases. Therefore, the effect which suppresses the bending which arises in an expansion-contraction boom by suspended load work becomes high. Further, by employing the back tension wire, the length of the suspended wire wound around the back side of the telescopic boom can be suppressed to be short. In addition, since the first tension sheave constituting the geometry is simply supported by the post, the structure of the post is also simplified.

  In order to achieve the above object, a boom deflection preventing device according to another invention includes a swivel base, a telescopic boom connected to the swivel base so as to be raised and lowered, a suspended load winch, and the suspended load winch. The present invention is applied to a work vehicle having a suspended wire that is unrolled and wound around a suspended sheave of an extendable boom. The boom deflection preventing device is provided on the back side of the telescopic boom, and has a post provided with a first tension sheave at the tip, a second tension sheave disposed at a predetermined portion of the swivel, and the telescopic A third tension sheave disposed opposite to the second tension sheave on the rear side of the boom, one end and the other end are connected to the third tension sheave and the rear end of the telescopic boom, respectively, and an intermediate portion A back tension wire wound around the first tension sheave. The said load wire is previously wound around the said 2nd tension sheave and the 3rd tension sheave before being wound around the said load sheave.

  Similar to the first aspect of the invention, when crane work is performed by such a work vehicle, the telescopic boom is generally raised at a required angle and extended to a required length. The suspended wire drawn from the suspended load winch is wound around the suspended sheave and hangs down, and the load is suspended through the hook. In this state, an axial force and a bending moment act on the telescopic boom, and the telescopic boom bends so that its back side is convex. That is, a tensile stress is generated on the back surface of the telescopic boom.

  According to this invention, the suspended wire drawn out from the suspended load winch is wound around the second tension sheave and the third tension sheave in advance before being wound around the suspended load sheave. By arranging the second tension sheave and the third tension sheave as described above, the second and third tension sheaves are arranged on the base end side and the back side of the telescopic boom. A back tension wire is disposed on the back side of the telescopic boom, and the back tension wire connects the third tension sheave and the back end of the telescopic boom. An intermediate portion of the back tension wire is supported by the first tension sheave. Since the first tension sheave is provided at the tip of the post erected on the back side of the telescopic boom, there is a certain distance between the first tension sheave and the back of the telescopic boom. That is, the tip of the telescopic boom, the first tension sheave, and the second tension sheave form a geometry that forms a virtual triangle by the back tension wire. By the way, since the load wire is wound around the second and third tension sheaves as described above, the tension of the load wire generated by the load operation becomes the tension of the back tension wire. Accordingly, the telescopic boom is bent by the suspended load operation (bending that the back side is convex), and at the same time, the back boom is bent by the tension of the back tension wire. These are offset and the bending of the telescopic boom is suppressed.

  Since the back tension wire has a triangular shape as described above, the bending moment acting on the telescopic boom (the bending moment in the direction in which the back side of the telescopic boom is concave) increases. Therefore, the effect which suppresses the bending which arises in an expansion-contraction boom by suspended load work becomes high. Further, by employing the back tension wire, the length of the suspended wire wound around the back side of the telescopic boom can be suppressed to be short. In addition, since the first tension sheave constituting the geometry is simply supported by the post, the structure of the post is also simplified.

  (2) A hydraulic cylinder that changes the distance between the first tension sheave and the back surface by changing the standing angle of the post may be provided. Alternatively, a hydraulic cylinder that changes the length of the post in the longitudinal direction to change the distance between the first tension sheave and the back surface may be provided.

  In this configuration, the distance between the first tension sheave and the back surface is changed by operating the hydraulic cylinder. That is, the angle of the back tension wire with respect to the back surface of the telescopic boom changes. Thereby, the bending moment in the direction in which the back side of the telescopic boom is concave is adjusted, and the deflection of the telescopic boom is suppressed according to the standing angle of the telescopic boom.

  (3) Deflection of the telescopic boom on the basis of the number of the suspension wire hanging on the second tension sheave and the third tension sheave, the number of the suspension wire hanging on the suspension sheave and the standing angle of the telescopic boom. It is preferable that a control device for driving the hydraulic cylinder is provided so that the pressure is minimized.

  In order to minimize the deflection of the telescopic boom, if the angles formed by the back tension wire and the suspended wire with respect to the longitudinal direction of the telescopic boom are θ1 and θ2, respectively, θ1 = θ2. Therefore, it is only necessary to control the hydraulic cylinder so that this relationship is established.

  If the standing angle of the telescopic boom is θ3, there is a relationship of θ2 = π / 2−θ3. Further, when the number of the hanging wire to the hanging sheave is X and the number of the hanging wire to the second and third tension sheaves is Y, sin θ1 / sin θ2 = Y / X. There is. Further, if the height of the post is L1, and the distance from the second tension sheave to the post (the distance along the longitudinal direction of the telescopic boom) is L2, there is a relationship of tan θ2 = L2 / L1. Accordingly, the control device controls the hydraulic cylinder so that θ1 = θ2 from these relationships, and the height L1 of the post is adjusted.

  (4) The telescopic boom includes a base boom coupled to the swivel base, a top boom, and one or a plurality of intermediate booms arranged therebetween, which are assembled in a nested manner. A base sheave may be provided, a tip sheave and a base end sheave may be provided at the tip and base ends of the intermediate boom, respectively, and an adjustment sheave may be provided at a predetermined portion of the swivel base. In this case, the back tension wire having the other end connected to the third tension sheave is hung around the first tension sheave, the adjustment sheave and the base sheave, and the base boom of the intermediate boom adjacent to the base boom is used. Preferably, the end sheave and the front sheave are repeatedly looped around in order, and the one end is connected to the base end fixing portion of the top boom.

  According to this configuration, the back tension wire is wound around the tip sheave of the first intermediate boom adjacent to the top boom in a state where one end of the back tension wire is fixed to the base end fixing portion of the top boom. It is wound around the base end sheave of the intermediate boom. Here, when the telescopic boom has a single intermediate boom, the back tension wire wound around the base end sheave of the intermediate boom is attached to the tip sheave, the adjustment sheave and the post of the base boom. It is wound around the first tension sheave provided, and one end of the back tension wire is fixed to the third tension sheave. On the other hand, when the crane boom includes a plurality of intermediate booms, the back tension wire wound around the proximal end sheave of the first intermediate boom is a second intermediate adjacent to the first intermediate boom. After being wound around the tip sheave of the boom, it is wound around the base end sheave of the intermediate boom. Similarly, the back tension wire is wound around the tip sheave and the base sheave of the adjacent intermediate boom, and finally the back tension wire is wound around the tip sheave, the adjustment sheave and the tension sheave of the base boom. After that, the other end of the back tension wire is fixed to the third tension sheave.

  By the way, when the weight of the suspended load increases in the suspended load operation, the tension of the back tension wire also increases in order to offset the bending of the telescopic boom. In other words, the axial force acting on the telescopic boom increases in the state where the bending of the telescopic boom is cancelled. Therefore, the mechanical strength (particularly buckling strength) of the telescopic boom and the mechanical strength (particularly buckling strength) of the telescopic cylinder for extending and contracting the telescopic boom must be ensured. As a result, the boom device including the telescopic cylinder is included. Tend to increase in weight.

  In this invention, since the single back tension wire is wound around the tip sheave and the base end sheave provided on the telescopic boom, even if the telescopic boom is telescopic during work, this is the cause. Thus, the back tension wire is not pulled or loosened. That is, the back tension wire can follow the expansion and contraction of the boom while maintaining a constant tension. In addition, since the back tension wire is laid out as described above, the tension generated in the back tension wire acts in the direction of extending the telescopic boom. In general, in a suspended load state, a force for contracting the boom is applied to the telescopic cylinder and the wire disposed inside the boom, but the tension of the tension wire acts in the direction to extend the crane boom, so that the telescopic cylinder and the wire are stretched. The applied force is suppressed.

  According to the present invention, a single tension wire is disposed on the back side of the telescopic boom in order to suppress bending of the telescopic boom, and the suspended load wire is connected to the tension wire via the second tension sheave and the third tension sheave. The tension of is loaded. Thereby, even if the length of a hanging wire is not so long, the tension | tensile_strength of a hanging wire is loaded by the back side of an expansion-contraction boom. In addition, the structure of the post and the first tension sheave that support the intermediate portion of the tension wire is simplified. Therefore, the mechanism for suppressing the bending of the telescopic boom can be simplified and reduced in weight. In addition, since the tension wire is laid out in a triangular shape on the back side of the telescopic boom, the effect of suppressing the bending of the telescopic boom is high.

FIG. 1 is a side view of a work vehicle in which a boom deflection preventing apparatus according to a first embodiment of the present invention is employed. FIG. 2 is a block diagram showing the configuration of the control device of the boom deflection preventing apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram schematically showing a boom deflection preventing apparatus according to a modification of the first embodiment of the present invention. FIG. 4 is a side view of a work vehicle in which the boom deflection preventing apparatus according to the second embodiment of the present invention is employed. FIG. 5 is a diagram schematically showing a conventional boom deflection preventing apparatus. FIG. 6 is a diagram schematically showing a conventional boom deflection preventing apparatus.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this Embodiment is only one aspect | mode of the boom bending prevention apparatus which concerns on this invention, and it cannot be overemphasized that an embodiment may be changed in the range which does not change the summary of this invention.

<First Embodiment>

  FIG. 1 is a side view of a work vehicle 31 in which a boom deflection preventing device 30 according to a first embodiment of the present invention is employed. The figure schematically shows the work vehicle 31 and the boom deflection preventing device 30.

1. Outline of work vehicle

  This work vehicle 31 is typically a crane vehicle. In the present embodiment, the work vehicle 31 includes a lower traveling body 32, a swivel base 33, and a boom device 34 (corresponding to an “expandable boom” described in the claims). The lower traveling body 32 includes a self-propelled device including a traveling engine and a steering mechanism, an actuator driving device including a hydraulic pump, a grounding safety device including an outrigger device 69, and a control device that comprehensively controls these devices. It has. The swivel base 33 is mounted on the lower traveling body 32 and can be swung with respect to the lower traveling body 32 via a turning actuator (not shown).

  The boom device 34 is extendable in the longitudinal direction as will be described later, and is connected to the swivel base 33 via the hoisting cylinder 35 in a hoistable state. A suspended load winch 36 is provided on the swivel base 33. The suspended load winch 36 includes a drum (not shown) and a suspended wire 37 having a required length, and the suspended wire 37 is wound around the drum and held. The hanging wire 37 drawn out from the drum is wound around a hanging wire sheave 38 provided in the boom device 34 and hangs down. In the present embodiment, the multiplying factor of the suspended wire sheave 38 is X (X is an integer). A hook 54 is provided at the tip of the hanging wire 37. When the suspended winch 36 is operated with the suspended load 70 suspended from the hook 54, the drum is driven and the suspended wire 37 is fed out or taken up from the drum, so-called suspended work is performed. Is called.

  A feature of the present embodiment is that a boom deflection preventing device 30 that suppresses the deflection generated in the boom device 34 during the hanging work is provided. Specifically, a post 39 is erected on the boom device 34, and a tension wire 40 (corresponding to a “back tension wire” recited in the claims) supported by the post 39 has a layout (hanging) described later. The control unit 41 (see FIG. 2) that changes the layout of the tension wire 40 so that the tension generated in the load wire 37 is loaded) and the bending generated in the boom device 34 is minimized. The feature is that it is built into the device. Thereby, the boom bending prevention apparatus 30 becomes a simple and lightweight structure.

2. Boom device

  The boom device 34 includes a boom main body 42 and a telescopic cylinder (not shown) that expands and contracts the boom main body 42. The boom body 42 includes a top boom 43, a first intermediate boom 44, a second intermediate boom 45, and a base boom 46. These consist of cylindrical members having a so-called closed cross section, and are assembled in a so-called nested manner as shown in the figure. A second intermediate boom 45 is inserted into the base boom 46, a first intermediate boom 44 is inserted into the second intermediate boom 45, and a top boom 43 is inserted into the first intermediate boom 44. . The second intermediate boom 45 is slidable in the longitudinal direction with respect to the base boom 46, and this relationship is between the second intermediate boom 45 and the first intermediate boom 44, and between the first intermediate boom 44 and the top boom. The same holds true for 43. The boom device 34 incorporates a telescopic cylinder (not shown). When the telescopic cylinder operates, adjacent booms slide relative to each other, and as a result, the length of the boom body 42 changes.

  A base end portion of the base boom 46 is connected to the swivel base 33. The base end portion of the base boom 46 is rotatably supported by the swivel base 33 via a undulation center pin (not shown). The hoisting cylinder 35 is interposed between the swivel base 33 and the base boom 46 as shown in FIG. When the hoisting cylinder 35 expands and contracts, the base boom 46 and, consequently, the boom main body 42 moves up and down.

3. Swivel

  The swivel base 33 is connected to the lower traveling body 32 via the turning actuator (typically a turntable and a hydraulic motor). Although not shown in the drawings, the actuator 33 such as a hydraulic control valve is arranged on the swivel base 33, and a counterweight or the like can be mounted. The control device including the control unit 41 may be installed on the swivel base 33.

4). Boom deflection prevention device

  The boom deflection prevention device 30 is wound around the post 39 and a tension sheave 47 (corresponding to a “first tension sheave” described in claims) provided on the post 39 and the suspension wire 37. A pair of tension sheaves 48 and 49 (corresponding to “second tension sheave” and “third tension sheave” recited in the claims), a tension wire 40, and the control unit 41 are provided.

  The post 39 is erected at a predetermined position on the back surface 50 of the boom main body 42 (in this embodiment, the back surface 50 of the base boom 46). Here, the back surface 50 of the base boom 46 is a surface on which tensile stress is generated during the lifting operation, and is a surface opposite to the side to which the hoisting cylinder 35 is connected. The post 39 includes a post body 51, a tension sheave 47, and a drive actuator 52.

  The post body 51 is made of a straight cylindrical member, and the base end portion of the post body 51 is connected to the base boom 46. The post body 51 may be formed of a cylindrical member having a so-called closed cross section, or may be a structure having a so-called open cross section. An anchor 53 is fixed to a predetermined position on the back surface 50 (in the present embodiment, near the tip of the base boom 46), and the base end of the post body 51 is connected to the anchor 53 via a pin. Therefore, the post body 51 can be rotated in the direction of the arrow 71. The tension sheave 47 is provided at the tip of the post body 51, and the tension wire 40 is hung as will be described later.

  The drive actuator 52 is a hydraulic linear motion cylinder in this embodiment. The drive actuator 52 is interposed between the post body 51 and the anchor 53, and can adjust the standing angle of the post body 51 by expanding and contracting. That is, the distance L1 (the distance in the direction orthogonal to the upper surface 50) from the back surface 50 of the base boom 46 to the tension sheave 47 is adjusted. However, the drive actuator 52 may be omitted, and the distance L1 may be constant. In that case, the post 39 is erected and fixed to the back surface 50 of the base boom 46.

  In the present embodiment, the distance L1 from the back surface 50 of the base boom 46 to the tension sheave 47 is indirectly adjusted by changing the standing angle of the post body 51 as described above. A structure in which the length of the post body 51 is changed may be used. Specifically, the post body 51 may be composed of a plurality of tubular members, and these may be assembled in a nested manner in the same manner as the boom body 42. That is, the post main body 51 can be expanded and contracted in the longitudinal direction, and the drive actuator 52 may be incorporated in the post main body 51. Then, when the drive actuator 52 operates, the post body 51 expands and contracts, and the distance L1 is directly adjusted.

  The tension sheave 48 is the tip of the top boom 43 and is disposed on the back surface 50 side of the boom main body 42. The position of the tension sheave 48 is not particularly limited, but may be a position on the opposite side of the suspended wire sheave 38 with the top boom 43 interposed therebetween. Further, the tension sheave 49 faces the tension sheave 48. The tension sheave 49 is paired with the tension sheave 48 on the back surface 50 side of the boom main body 42, and is disposed so as to face the longitudinal direction of the top boom 43. A tension wire 40 is connected to the tension sheave 49 as described later. In this embodiment, the multiplication of the tension sheaves 48 and 49 is Y (Y is an integer).

  The suspended load wire 37 fed out from the suspended load winch 36 is wound around the tension sheave 48 and the tension sheave 49 as shown in FIG. Thus, the suspended wire 37 is previously wound around the tension sheaves 48 and 49, and then suspended around the suspended wire sheave 38 and wound around the hook 54. Although not shown, an idle sheave may be disposed at a position facing the suspended wire sheave 38 with the top boom 43 interposed therebetween. In this case, the load wire 37 wound around the tension sheave 48 and the tension sheave 49 is hung on the load wire sheave 38 via the idle sheave.

  The tension wire 40 is disposed on the back surface 50 side of the boom body 42. Although one end portion 55 and the other end portion 56 of the tension wire 40 are not shown in the drawing, a required end treatment (typically, alloying) is performed. One end 55 of the tension wire 40 is connected and fixed to a predetermined position of the swivel base 33 as shown in FIG. Specifically, the one end portion 55 secured with the alloy is engaged with an anchor (not shown) provided on the swivel base 33. The position of the anchor is not particularly limited, but in the present embodiment, the anchor is disposed on the central axis of the undulation center pin. However, the position of the anchor may be behind the swivel base 33 and behind the undulation center pin that supports the base end of the base boom 46. Note that, since the base boom 46 is connected to the swivel base 33, in this specification, even when the anchor is actually fixed to the base boom 46, it is interpreted as “fixed to the swivel base 33”. Shall. Moreover, if the said conditions are satisfy | filled, the one end part 55 of the tension wire 40 may be fixed to the base boom 46 via the bracket etc.

  The tension wire 40 with the one end 55 fixed in this way is wound around the tension sheave 47. The other end 56 of the tension wire 40 is connected to the tension sheave 49 as described above. Since this figure is a schematic diagram, a connection structure between the tension wire 40 and the tension sheave 49 is not shown, but a known structure is adopted as the connection structure between the two. For example, the other end 56 of the tension wire 40 is coupled to the support frame in a state where the tension sheave 39 is supported by a required support frame.

  FIG. 2 is a block diagram illustrating a configuration of the control unit 41.

  As shown in the figure, the control unit 41 includes a main calculation unit 61, angle sensors 64 and 65, and a boom length sensor 66. However, as described above, the control device comprehensively controls the self-propelled device, the actuator driving device, and the grounding safety device. Therefore, the control device has other sensors and actuators for controlling them. Although a drive circuit and the like are provided, they are not shown in the figure.

  The main calculation unit 61 is configured as a microcomputer mainly including a CPU (Central Processing Unit) 57, a ROM (Read Only Memory) 58, a RAM (Random Access Memory) 59, and an EEPROM (Electrically Erasable and Programmable ROM) 60. . The main arithmetic unit 61 is connected to an ASIC (Application Specific Integrated Circuit) 63 via a bus 62. A program or the like for controlling the operation of the boom deflection prevention device 30 is stored in the ROM 58. The RAM 59 is used as a storage area or a work area for temporarily recording various data used when the CPU 57 executes the program. In addition, settings, flags, and the like that should be retained after the work vehicle 31 is powered off are stored in the EEPROM 60.

  The angle sensor 64 detects the standing angle of the boom main body 42 and outputs a boom angle signal. In this case, the standing angle θ3 (see FIG. 1) is detected with reference to the horizontal direction. The angle sensor 65 detects the standing angle of the post body 51 and outputs a post angle signal. In this case, the angle θ4 at which the post main body 51 is inclined with respect to the same direction is detected with the direction orthogonal to the back surface 50 of the base boom 46 as a reference. That is, the inclination angle θ4 is detected with reference to the state in which the post body 51 stands upright on the base boom 46. The boom length sensor 66 detects the extension length of the boom main body 42 and outputs a boom extension signal. In this case, a distance L2 (a distance along the longitudinal direction of the boom main body 42) from the position where the post main body 51 is provided to the tip of the top boom 43 is detected.

  The ASIC 63 generates a phase excitation signal and the like for energizing the electromagnetic switching valve 67 in accordance with a command from the CPU 57. This signal is given to the drive circuit 68 of the electromagnetic switching valve 67, and the electromagnetic switching valve 67 is actuated via this drive circuit 68. The electromagnetic switching valve 67 is a switching valve for supplying pressure oil to the drive actuator 52 (the aforementioned hydraulic cylinder). When this electromagnetic switching valve 67 is actuated, the drive actuator 52 expands and contracts, whereby the post body 51 rises and falls from the upright state. That is, the inclination angle θ4 changes.

5. Effect

  When crane work is performed by the work vehicle 31, the boom device 34 is raised at a required angle and extended to a required length. The suspended load wire 37 fed out from the suspended load winch 36 is wound around the tension sheaves 48 and 49 and the suspended load wire sheave 38 and hangs down. A suspended load 70 is suspended from a hook 54 provided at the tip of the suspended load wire sheave 38. In this state, tension is generated in the hanging wire 37, and the axial force and the bending moment act on the boom main body 42 by this tension, and the boom main body 42 bends so that the back surface 50 side is convex. That is, a tensile stress is generated on the back surface 50 of the boom body 42.

  The suspended wire 37 is wound around the tension sheaves 48 and 49 in advance before being hung around the suspended wire sheave 38. These tension sheaves 48 and 49 are disposed at the tip of the top boom 43 and on the back surface 50 side. On the other hand, the tension wire 40 is disposed on the back surface 50 side of the boom body 42. The other end portion 56 of the tension wire 40 is connected to a tension sheave 49, and the one end portion 55 is fixed to the swivel base 33 as described above. The intermediate portion of the tension wire 40 is supported by a tension sheave 47.

  Since the tension sheave 47 is provided at the tip of the post body 51, there is a certain distance L1 between the tension sheave 47 and the back surface 50 of the boom body 42. That is, the tension sheave 48 provided at the tip of the top boom 43, the tension sheave 47, and the predetermined position of the swivel base 33 (one end portion 55 of the tension wire 40) form a geometry that forms a virtual triangle by the tension wire 40. By the way, since the load wire 37 is wound around the tension sheaves 48 and 49 as described above, the tension of the load wire 37 generated by the load work causes the tension wire 40 to have the same magnitude. . Therefore, the boom main body 42 is bent by the suspended load operation, and at the same time, the boom main body 42 is bent in the opposite direction by the tension of the tension wire 40. That is, the boom body 42 is bent so that the back surface 50 side is convex due to the tension of the lifting wire 37, but the boom body 42 is bent so that the back surface 50 side is concave due to the tension of the tension wire 40. Arise. These bends are offset and the bend of the boom body 42 is suppressed.

  Since the tension wire 40 has a triangular shape as described above, the bending moment acting on the boom main body 42 due to the tension of the tension wire 40 (the bending moment in the direction in which the back side 50 is concave) increases. Therefore, the bending which arises in the boom main body 42 by the tension | tensile_strength of the hanging load wire 37 is canceled effectively. Moreover, in the present embodiment, since the tension wire 40 is employed, the length of the suspended wire 37 disposed on the back surface 50 side of the boom body 42 can be suppressed to be short. In addition, since the tension sheave 47 constituting the geometry is simply supported by the post body 51, the structure of the post 39 is also simplified.

  As described above, the boom bending prevention device 30 according to the present embodiment can effectively suppress the bending of the boom main body 42 caused by the lifting work, while having a simple and lightweight structure.

  In the present embodiment, the control unit 41 grasps the angle θ3 of the boom body 42 by the angle sensor 64, grasps the distance L2 by the boom length sensor 66, and the inclination angle θ4 of the post body 51 by the angle sensor 65. To figure out. And the control part 41 adjusts the distance L1 as mentioned later, and the bending of the boom main body 42 is suppressed to the minimum.

When the drive actuator 52 is operated, the inclination angle θ4 is changed, and the height of the tension sheave 47, that is, the distance L1 is changed. If the distance from the upper surface 50 of the base boom 46 to the tension sheave 47 (distance in a direction perpendicular to the upper surface 50) is L0 when the post body 51 is upright, the distance L1
L1 = L0 × cos θ4 (1).

By changing the distance L1, the angle θ1 formed by the tension wire 40 with respect to the longitudinal direction of the boom body 42 changes.
Here, there is a relationship of tan θ1 = L1 / L2 (2).

  If this angle θ1 increases, generally, the bending moment acting on the boom main body 42 based on the tension of the tension wire 40 (the bending moment in the direction in which the rear surface 50 side of the boom main body 42 becomes concave) increases. On the other hand, as the rising angle θ3 of the boom body 42 is smaller, generally, the bending moment acting on the boom body 42 (the bending moment in the direction in which the rear surface 50 side of the boom body 42 protrudes) increases. Since the angle θ1 is adjusted by adjusting the distance L1 (that is, by adjusting the tilt angle θ4), the angle θ1 can be adjusted according to the standing angle θ3 of the boom body 42. Become.

  When the post body 51 itself is configured to expand and contract as described above, the distance L1 is easily adjusted and detected by providing the post body 51 with a post length sensor.

Further, if the standing angle of the boom body 42 is θ3, the angle θ3 and the angle θ2 formed by the hanging wire 37 with respect to the longitudinal direction of the boom body 42,
θ2 = π / 2−θ3 (3)

  As described above, the multiplication factor of the suspension wire 37 to the tension sheaves 48 and 49 is Y, and the multiplication factor of the suspension wire 37 to the suspension wire sheave 38 is X. If X = Y is satisfied, θ1 = θ2 may be satisfied in order to minimize the bending of the boom main body 42. Since the control unit 41 grasps the distance L2 and the angles θ3 and θ4 by the various sensors 64 to 66, the control unit 41 calculates the distance L1 at which θ1 = θ2 by the above formulas (1) to (3). Based on this, the drive actuator 52 is operated to adjust the tilt angle θ4. When X ≠ Y, there is a relationship of sin θ1 / sin θ2 = Y / X. The control unit 41 calculates the distance L1 under such a condition and operates the drive actuator 52 based on this to adjust the tilt angle θ4.

  When L1 ≦ L0, the bending of the boom body 42 is completely canceled, and the boom body 42 receives only the bending moment. It is also expected that L1> L0. In this case, the bending of the boom main body 42 is not completely cancelled, but the bending is minimized.

  Thus, even if the drive actuator 52 is connected to the post body 51 and the distance L1 can be adjusted, the post body 51 is simply rotated or expanded / contracted. Compared to the case where a winch for adjusting the length of the back tension wire is adopted, a simpler and lighter structure is realized.

  But the said control apparatus may be abbreviate | omitted.

6). Modified example

  FIG. 3 is a side view of the work vehicle 31 in which the boom deflection preventing device 75 according to the modification of the above embodiment is employed. This figure schematically shows the work vehicle 31 and the boom deflection preventing device 75.

  The feature of this modification is that the boom main body 42 includes a plurality of sheaves 76 to 80, and the tension wires 40 are laid out as described later. Thereby, the axial force which acts on the boom main body 42 during the suspended load operation, that is, the force applied to the telescopic cylinder or the like is suppressed.

  The boom deflection preventing device 75 according to this modification includes a first tip sheave 76 and a second tip sheave 78, a first base end sheave 77 and a second base end sheave 79, a base sheave 80, and adjustment sheaves 81 and 82. And. The first intermediate boom 44 is provided with a first tip sheave 76 and a first base end sheave 76, the second intermediate boom 45 is provided with a second tip sheave 78 and a second base end sheave 79, and the base boom 46 is provided with a base sheave. 80 is provided. The adjustment sheaves 81 and 82 are provided at predetermined positions on the swivel base 33. One end portion 55 of the tension wire 40 is fixed to the base end fixing portion 83 of the top boom 43, and the other end portion 56 of the tension wire 40 is connected to the tension sheave 49. The structure of the base end fixing portion 83 is not particularly limited, but it is only necessary to exhibit a function as an anchor to which the other end portion 55 of the tension wire 40 subjected to the above-described terminal treatment can be connected.

  The first intermediate boom 44 is formed in a cylindrical shape as described above, and the first tip sheave 76 is disposed inside the first intermediate boom 44. The first tip sheave 76 is rotatably supported by the first intermediate boom 44 via a support pin (not shown), and the axial direction of the support pin intersects the longitudinal direction of the first intermediate boom 44. (In this embodiment, the direction is perpendicular to the paper surface in the figure).

  The second intermediate boom 45 and the base boom 46 are also formed in a cylindrical shape as described above. The second tip sheave 78 is arranged inside the tip of the second intermediate boom 45, and the base sheave 80 is arranged inside the tip of the base boom 46. The second tip sheave 78 and the base sheave 80 are rotatably supported by the second intermediate boom 45 and the base boom 46 via support pins (not shown). The axial directions of these support pins are the same as the axial directions of the support pins that support the first tip sheave 76.

  The first base end sheave 77 is provided inside the base end portion of the first intermediate boom 44, and the second base end sheave 79 is provided inside the base end portion of the second intermediate boom 45. These are rotatably supported by the first intermediate boom 44 and the second intermediate boom 45 through support pins (not shown). The axial direction of each support pin is along the direction intersecting with the longitudinal direction of the first intermediate boom 44 and the second intermediate boom 45, and is parallel to the axial direction of the support pin that supports the first tip sheave 76.

  The adjustment sheaves 81 and 82 are arranged at predetermined positions on the swivel base 33. Although these positions are not particularly limited, in this modification, it is desirable that they are located behind the swivel base 33 and in the vicinity of the undulation center pin that supports the base end portion of the base boom 46. In this modification, two adjustment sheaves 81 and 82 are provided, but the number of adjustment sheaves is not particularly limited, and a single adjustment sheave may be provided, or three or more adjustment sheaves may be provided. A sheave may be provided.

  The tension wire 40 is wound around each of the sheaves 76 to 82 described above. One end portion 55 of the tension wire 40 is fixed to the proximal end fixing portion 83, and the tension wire 40 includes a first distal end sheave 76, a first proximal end sheave 77, a second distal end sheave 78, a second proximal end sheave 79, It is hung around the base sheave 80 in order, and is further hung around the tension sheave 47 via the adjustment sheaves 81 and 82. The other end 56 of the tension wire 40 is connected to the tension sheave 49 as described above.

7). Effect

  According to the boom bending prevention device 75 according to this modification, the bending of the boom main body 42 is suppressed in the same manner as the boom deflection prevention device 30 according to the above embodiment. Furthermore, since the tension wire 40 is laid out as described above and wound around the sheaves 76 to 82, even if the boom main body 42 is expanded and contracted during the lifting operation, the relative sheaves 76 to 82 are relative to each other. A tensile force does not act on the tension wire 40 or the tension wire 40 is not loosened only by changing the positional relationship. That is, the tension wire 40 can follow the expansion and contraction of the boom body 42 while maintaining a constant tension.

  In addition, since the tension wire 40 is laid out as described above, the tension generated in the tension wire 40 acts in a direction in which the boom body 42 is extended. Therefore, there is an advantage that an excessive compressive force does not act on the telescopic cylinder or the like while suppressing the bending. Further, when the tilt angle θ4 of the post body 51 is adjusted by the control unit 41 so that θ1 = θ2 when X = Y is satisfied, the axial force acting on the boom body 42 by the suspended load 70 Is completely cancelled. Even when X ≠ Y, the axial force is completely canceled by correcting the tilt angle θ4 on the condition. As a result, the boom body 42 can be designed to be light and compact.

  In the above embodiment and the modification, the tension wire 40 is single, but a pair of tension wires 40 may be laid out as shown in FIG. In this case, it is preferable that the pair of tension wires 40 be arranged at a predetermined interval in a direction perpendicular to the paper surface. Naturally, the sheaves 76 to 82 on which the pair of tension wires 40 are hung are also arranged at predetermined intervals in the same direction.

  Moreover, although the boom main body 42 is provided with the two intermediate booms 44 and 45, a single intermediate boom may be sufficient and three or more may be sufficient. When the boom body 42 includes a single intermediate boom, the second tip sheave 78 and the second base sheave 79 can be omitted. Moreover, when the boom main body 42 is provided with three or more intermediate booms, the distal sheave and the proximal sheave are provided in the same manner on the intermediate booms 44 and 45.

  The actual boom device 34 is provided with hydraulic piping and various sensors and brackets. In the embodiment and the modification, the tension wire 40 is disposed inside the boom device 34. At this time, the tension wire 40 is laid out in a state where interference with the hydraulic piping or the like is avoided. Needless to say.

<Second Embodiment>

  FIG. 4 is a side view of the work vehicle 31 in which the boom deflection preventing device 85 according to the second embodiment of the present invention is employed. The figure schematically shows the work vehicle 31 and the boom deflection preventing device 85.

  The difference between the boom deflection preventing device 85 according to the present embodiment and the boom deflection preventing device 30 according to the first embodiment is a tension sheave 48 (corresponding to “second tension sheave” recited in the claims). And the position of the tension sheave 49 (corresponding to the “third tension sheave” recited in the claims). That is, in the first embodiment, the tension sheave 48 is fixed to the distal end portion of the top boom 43, and the tension sheave 49 is disposed opposite to the tension sheave 48 (see FIG. 1). The tension sheave 48 is disposed at a predetermined portion of the swivel base 33, and the tension sheave 49 is disposed opposite to the tension sheave 48 on the back surface 50 side of the boom body 42.

  The tension sheave 48 is fixed to the swivel base 33. However, the tension sheave 48 may be fixed to the base boom 46. In this specification, since the base boom 46 is connected to the swivel base 33, the tension sheave 48 is fixed to the base boom 46, and it is interpreted as “fixed to the swivel base 33”. . Specifically, the tension sheave 48 is fixed to the swivel base 33 via a support pin (not shown). The center axis of the support pin preferably coincides with the center axis of the undulation center pin that supports the base boom 46. However, the center axis of the support pin may not coincide with the center axis of the undulation center pin. Further, the tension sheave 49 faces the tension sheave 48. The tension sheave 49 is paired with the tension sheave 48 on the back surface 50 side of the boom main body 42, and is disposed so as to face the longitudinal direction of the top boom 43. The tension wire 40 is connected to the tension sheave 49 as described later. In this embodiment as well, the multiplication factor of the tension sheaves 48 and 49 is Y (Y is an integer).

  As shown in FIG. 4, the suspended wire 37 fed out from the suspended load winch 36 is wound around the tension sheave 48 and the tension sheave 49 before being wound around the suspended wire sheave 38. After the suspension wire 37 is wound around the tension sheaves 48 and 49 in advance as described above, it is hung on the suspension wire sheave 38 via an idle sheave (not shown) provided on the swivel base 33. In the present embodiment, an idle sheave 86 is provided at the tip of the top boom 21. The suspended load wire 37 is wound around the idle sheave provided on the swivel base 33, then the idle load sheave 86, and the suspended load wire 37 is wound around the hook 54.

  Similar to the first embodiment, the tension wire 40 is disposed on the back surface 50 side of the boom body 42. One end 55 of the tension wire 40 is connected to a tension sheave 49 as shown in FIG. Since this figure is a schematic diagram, the connection structure between the tension wire 40 and the tension sheave 49 is not shown, but a known structure is adopted for the connection structure between them as in the first embodiment. For example, one end 55 of the tension wire 40 is connected to the support frame in a state where the tension sheave 39 is supported by a required support frame. The tension wire 40 with the one end 55 fixed in this way is wound around the tension sheave 47. The other end 56 of the tension wire 40 is connected to the top boom 43 as shown in FIG. Specifically, it is fixed to an anchor portion 87 provided at the tip of the top boom 43 and provided on the back surface 50 side.

  The tension wire 40 with the one end 55 fixed in this way is wound around the tension sheave 47. The other end 56 of the tension wire 40 is connected to the tension sheave 49 as described above. Since this figure is a schematic diagram, a connection structure between the tension wire 40 and the tension sheave 49 is not shown, but a known structure is adopted as the connection structure between the two. For example, the other end portion 56 of the tension wire 40 is coupled to the support frame in a state where the tension sheave 40 is supported by a required support frame.

  In the present embodiment, it is obvious that the same operational effects as those in the first embodiment can be obtained. Of course, the modification of the first embodiment is also valid in this embodiment.

DESCRIPTION OF SYMBOLS 30 ... Boom bend prevention apparatus 31 ... Work vehicle 33 ... Swing stand 34 ... Boom apparatus 35 ... Hoisting cylinder 36 ... Winch for hanging load 37 ... Hanging wire 38 ...・ Hanging wire 39 ... Post 40 ... Tension wire 41 ... Control unit 42 ... Boom body 43 ... Top boom 44 ... First intermediate boom 45 ... Second intermediate boom 46 ... Base boom 47 ... Tension sheave 48 ... Tension sheave 49 ... Tension sheave 50 ... Back 51 ... Post body 52 ... Drive actuator 53 ... Anchor 54 ... Hook 55 ... One end 56 ... Other end 64 ... Angle sensor 65 ... Angle sensor 66 ... Boom length sensor 70 ... Suspended load 75 ... Boom deflection prevention device 76 ...・ First Tip sheave 77 ... first base sheave 78 ... second tip sheave 79 ... second base sheave 80 ... base sheave 81 ... adjustment sheave 82 ... adjustment sheave 83 ... Base end fixing part 85 ... Boom deflection preventing device 86 ... Idle sheave 87 ... Anchor part

Claims (6)

Work having a swivel base, a telescopic boom connected to the swivel base so as to be raised and lowered, and a suspended load winch and a suspended load wire fed out from the suspended load winch and hung around a suspended sheave of the telescopic boom. Applied to the car,
A post erected on the back side of the telescopic boom and provided with a first tension sheave at the tip;
A second tension sheave disposed at the rear end of the telescopic boom;
A third tension sheave disposed opposite to the second tension sheave on the back side of the telescopic boom;
A back tension wire having one end and the other end connected to a predetermined portion of the swivel base or the telescopic boom and the third tension sheave, respectively, and an intermediate portion wound around the first tension sheave;
The boom deflection preventing device, wherein the suspended wire is wound around the second tension sheave and the third tension sheave before being wound around the suspended sheave.   The boom deflection preventing apparatus according to claim 1, further comprising a hydraulic cylinder that changes a standing angle of the post to change a distance between the first tension sheave and the back surface.   The boom deflection preventing apparatus according to claim 1, further comprising a hydraulic cylinder that changes a longitudinal length of the post to change a distance between the first tension sheave and the back surface.   Based on the number of the hanging wire to the second tension sheave and the third tension sheave, the number of the hanging wire to the hanging sheave, and the standing angle of the telescopic boom, the bending of the telescopic boom is minimized. The boom bending prevention apparatus according to claim 2 or 3, wherein a control device for driving the hydraulic cylinder is provided. The telescopic boom has a base boom coupled to the swivel base, a top boom, and one or a plurality of intermediate booms arranged therebetween, which are assembled in a nested manner.
A base sheave is provided at the tip of the base boom,
A tip sheave and a base end sheave are provided at the tip end and the base end of the intermediate boom,
An adjustment sheave is provided in a predetermined part of the swivel,
The back tension wire having the other end connected to the third tension sheave is routed around the first tension sheave, the adjustment sheave and the base sheave, and the base sheave of the intermediate boom adjacent to the base boom and The boom bending prevention apparatus according to any one of claims 1 to 4, wherein the one end is connected to a base end fixing portion of the top boom by being repeatedly wound around a tip sheave in order. Work having a swivel base, a telescopic boom connected to the swivel base so as to be raised and lowered, and a suspended load winch and a suspended load wire fed out from the suspended load winch and hung around a suspended sheave of the telescopic boom. Applied to the car,
A post erected on the back side of the telescopic boom and provided with a first tension sheave at the tip;
A second tension sheave disposed at a predetermined portion of the swivel;
A third tension sheave disposed opposite to the second tension sheave on the back side of the telescopic boom;
A back tension wire having one end and the other end connected to the third tension sheave and the rear end of the telescopic boom, respectively, and an intermediate portion wound around the first tension sheave;
The boom deflection preventing device, wherein the suspended wire is wound around the second tension sheave and the third tension sheave before being wound around the suspended sheave.

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