JP5873840B2 - Multi-arm hydraulic system and deep excavator - Google Patents

Description

  The present invention relates to a multi-arm hydraulic device and a deep excavator.

  Generally, when excavating a vertical shaft deep in the ground in civil engineering work, a deep excavator is preferably used. The deep digging machine includes a self-propelled vehicle body, a boom provided on the vehicle body so as to be able to move up and down, an outer cylinder provided on the tip side of the boom so as to extend upward and downward, and the outer cylinder A telescopic arm having a plurality of inner cylinders that are accommodated inside and outside, and a telescopic stationary sheave fixed to the outer cylinder, and an expansion cylinder arranged along the length of the outer cylinder; A sheave attachment that is attached to the telescopic cylinder and moves in the length direction of the outer cylinder, a movable sheave for expansion and contraction provided on the sheave attachment, one end of the sheave being locked to the outer cylinder, and the other end to the inner cylinder An intermediate portion is provided with a telescopic rope wound around a telescopic fixed sheave and a telescopic movable sheave.

  This deep digging machine according to this prior art reduces the telescopic cylinder in a state where the telescopic arm provided on the tip side of the boom is held perpendicular to the ground, thereby lowering the inner cylinder of the telescopic arm downward from the outer cylinder. Elongate. A clamshell bucket is attached to the tip (lower end) of the inner cylinder, and the earth and sand can be excavated by this clamshell bucket.

  After gripping the excavated earth and sand with the clamshell bucket, open the clamshell bucket with the telescopic cylinder extended and the inner cylinder pulled up into the outer cylinder by the telescopic rope. (See Patent Document 1).

JP-A-62-82131

  By the way, in the above-described deep excavator according to the prior art, the tube of the telescopic cylinder is attached to the outer cylinder of the telescopic arm, and the sheave fixture (hanger) that supports the movable sheave for expansion and contraction to the rod protruding downward from the tube. Is installed.

  For this reason, the deep excavator according to the prior art is fixed to the movable movable sheave and the outer cylinder supported by the sheave fitting by extending the rod of the expansion cylinder downward and moving the sheave fitting downward. The telescopic rope is wound between the telescopic fixed sheave, and the inner cylinder to which the telescopic rope is locked can be pulled up into the outer cylinder.

  However, in the deep excavator according to the prior art, since the tube of the expansion cylinder is attached to the outer cylinder, the sheave fixture is moved downward by the expansion cylinder, and the movable sheave between the expansion and contraction is fixed between the expansion sheave and the expansion sheave. When the telescopic rope is wound, the weight of the sheave fitting acts on the telescopic rope, but the weight of the tube of the telescopic cylinder does not act. Thus, when the inner cylinder is pulled into the outer cylinder together with the earth and sand excavated by the clamshell bucket, the weight of the expansion cylinder itself cannot be used as the lifting force, and the inner cylinder is lifted by the expansion cylinder. May not be performed efficiently.

(1) A hydraulic device for a multi-stage arm according to the invention of claim 1 is configured such that the multi-stage arm is contracted by extending the hydraulic cylinder, the multi-stage arm is extended by contracting the hydraulic cylinder, and the hydraulic cylinder is extended and contracted. The hydraulic cylinder has a rod end connected to the outer cylinder of the multistage arm, and a sheave fixture that supports the movable sheave for expansion and contraction is attached to the tube that has become a free end. Prohibit the extension position to extend the hydraulic cylinder to control the flow of pressure oil to the cylinder, the contraction position to contract the hydraulic cylinder, and the supply of pressure oil to the hydraulic cylinder and the return of pressure oil from the hydraulic cylinder A control valve that switches to a neutral position, a first oil passage between the bottom side oil chamber and the control valve of the hydraulic cylinder, a rod side oil chamber and the control valve of the hydraulic cylinder A first oil passage, a counter balance valve provided in the first oil passage , the pilot port of which is connected to the second oil passage, and the bottom oil chamber of the first oil passage A relief valve having a primary side connected to the oil passage between the valve and the counter balance valve, and a secondary side connected to the second oil passage, and the pressure oil in the second oil passage to the low pressure side when the hydraulic cylinder is extended Operates to retract the hydraulic cylinder with a permit position permitting escape and a switching valve that switches to a prohibition position prohibiting the escape of pressure oil in the second oil passage to the low pressure side when the hydraulic cylinder contracts When the member is operated, the switching valve is switched to the prohibited position, and the counter balance valve is opened by the pressure oil corresponding to the operation amount of the operation member acting on the counter balance valve via the pilot port. Cylinder bottom oil chamber pressure Flows out to the low pressure side of the hydraulic circuit via the counter balance valve and the operating member is operated to extend the hydraulic cylinder, the switching valve is switched to the permitted position, and the pressure oil in the rod side oil chamber of the hydraulic cylinder is It flows out to the low voltage | pressure side of a hydraulic circuit through a control valve and a switching valve, It is characterized by the above-mentioned.
(2) The invention according to claim 2 is the multistage arm hydraulic device according to claim 1, wherein the hydraulic circuit has a counterbalance in an oil path between the counterbalance valve and the control valve in the first oil path. A slow return valve with a variable throttle provided in series with the valve and the control valve is further provided .
(3 ) A deep excavator according to the invention of claim 3 is provided so as to extend in the upward and downward directions to the vehicle body capable of self-propelling, a boom provided to the vehicle body so as to be able to be lifted and lowered, A multistage arm having an outer cylinder and a plurality of inner cylinders accommodated inside the outer cylinder so as to be expandable and contractable in the lengthwise direction, and a hydraulic pressure disposed along the lengthwise direction of the outer cylinder constituting the multistage arm A cylinder, a telescopic fixed sheave fixed to the outer cylinder, and a sheave attachment that is attached to the hydraulic cylinder and moves in the length direction of the outer cylinder so as to approach or separate from the telescopic stationary sheave; The movable sheave for expansion and contraction provided in the sheave fixture, one end side is locked to the outer cylinder and the other end side is locked to the inner cylinder that is the innermost of the inner cylinders, and the middle part is a fixed sheave for expansion and contraction. Equipped with a telescopic rope wound around a telescopic movable sheave In the deep excavation machine, the hydraulic cylinder has a tube, and a rod having one side fixed to the piston in the tube and the other side protruding to the outside from the tube. The front end of the multistage arm is attached to the outer cylinder of the multistage arm, the tube of the hydraulic cylinder is used as a free end, and the sheave attachment is attached to the tube of the hydraulic cylinder, and the hydraulic apparatus for the multistage arm according to claim 1 or 2 is further provided. It is characterized by providing.
( 4 ) The invention of claim 4 is the deep excavation machine according to claim 3 , wherein the tip of the rod of the hydraulic cylinder is attached to the upper side of the outer cylinder.

  According to the present invention, the hydraulic cylinder can be operated efficiently.

It is a side view which shows the deep excavation machine by embodiment of this invention in the state which the expansion-contraction arm reduced most. It is a side view which shows a deep excavation machine in the state which the expansion-contraction arm extended most. It is a side view which shows the expansion-contraction arm in FIG. 1 alone. It is the front view which looked at the expansion-contraction arm from the arrow IV-IV direction in FIG. It is a perspective view which shows a telescopic arm alone. FIG. 6 is an enlarged perspective view of main parts showing the outer cylinder, the telescopic cylinder, the telescopic fixed sheave, the sheave mounting tool, the telescopic movable sheave, the sheave mounting guide rail, and the like in FIG. 5. It is a perspective view of the principal part expansion which shows a sheave attaching tool, a movable sheave for expansion and contraction, a movable sheave for pushing, a sheave attaching tool guide rail, and the like. It is a front view of the principal part expansion which expands and shows the fixed sheave for expansion-contraction in FIG. It is a schematic diagram which shows the expansion-contraction mechanism of an expansion-contraction arm in the state which the expansion-contraction arm contracted. It is a schematic diagram which shows the expansion-contraction mechanism of an expansion-contraction arm in the state which the expansion-contraction arm extended. It is sectional drawing which looked at the expansion-contraction arm, the boom bracket, etc. from the arrow XI-XI direction in FIG. FIG. 4 is a cross-sectional view of the telescopic arm, the telescopic cylinder, the sheave mounting tool, the telescopic movable sheave, etc., as viewed from the direction of arrows XII-XII in FIG. FIG. 4 is a cross-sectional view of the telescopic arm, the telescopic cylinder, the sheave mounting tool, the pushable movable sheave, and the like when viewed from the direction of arrows XIII-XIII in FIG. 3. It is sectional drawing which looked at the expansion-contraction arm, sheave attachment opening, the fixed sheave for pushing, etc. from the arrow XIV-XIV direction in FIG. It is a side view which shows the state which put the expansion-contraction arm on the ground with the deep excavator as a transport posture. It is a front view which shows the modification which has arrange | positioned the expansion-contraction cylinder, the expansion and contraction fixed sheave, the sheave attachment, the expansion and contraction movable sheave, the sheave attachment guide rail and the like on the front side of the outer cylinder. It is a figure which shows the whole structure of a hydraulic apparatus.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a hydraulic device for a multistage arm and a deep excavator according to the present invention will be described in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 1 denotes a deep excavator according to the present embodiment. The deep excavator 1 is mounted on a crawler type lower traveling body 2 capable of self-propelling and capable of turning on the lower traveling body 2. And a vehicle body made up of the upper revolving body 3.

  The upper swing body 3 includes a swing frame 3A as a base, a cab 3B disposed on the front left side of the swing frame 3A, a counterweight 3C provided on the rear end side of the swing frame 3A, and an engine inside. And a building cover 3D that accommodates a mounting device such as a hydraulic pump (both not shown in FIG. 1).

  Reference numeral 4 denotes a boom provided on the front side of the upper swing body 3 so as to be able to move up and down. The base end side of the boom 4 is attached to the front side of the revolving frame 3 </ b> A, and the excavator 11 described later is attached to the distal end side of the boom 4. A boom cylinder 4A is provided between the boom 4 and the swing frame 3A, and the boom 4 moves up and down with respect to the upper swing body 3 by expanding and contracting the boom cylinder 4A. The bottom side of the excavator swing cylinder 4B is attached to the upper surface side of the boom 4, and the rod side of the excavator swing cylinder 4B is attached to the excavator 11.

  Next, the excavator 11 that is attached to the tip end side of the boom 4 and excavates a vertical shaft deeply in the ground will be described.

  Reference numeral 11 denotes an excavator attached to the tip side of the boom 4, and the excavator 11 includes a multistage arm (extensible arm) 12, an extendable cylinder 25, a sheave attachment 29, and a telescopic fixed sheave 31. The movable sheave 33 for expansion and contraction and the rope 34 for expansion and contraction are provided. Reference numeral 111 denotes a multi-stage arm drive mechanism, which includes the telescopic cylinder 25, the sheave attachment 29, the telescopic fixed sheave 31, the telescopic movable sheave 33, the telescopic rope 34, and the like. .

  Reference numeral 12 denotes a telescopic multi-stage arm (expandable arm) attached to the front end side of the boom 4 so as to extend upward and downward. As shown in FIG. 9 and the like, the telescopic arm 12 includes an outer cylinder 13 positioned on the outermost side and a later-described first stage accommodated in the lengthwise direction on the inner peripheral side of the outer cylinder 13 (movable). An inner cylinder 21 of the eye and a second-stage inner cylinder 23 (described later) housed on the inner peripheral side of the first-stage inner cylinder 21 so as to be extendable in the length direction.

  Here, as shown in FIGS. 11 to 14, the outer cylinder 13 includes a rear surface 13A attached to the front end side of the boom 4, a front surface 13B facing the rear surface 13A with a distance in the front and rear directions, the rear surface 13A and the front surface. A left side surface 13C and a right side surface 13D facing in the left and right directions across 13B, a left inclined surface 13E disposed obliquely between the rear surface 13A and the left side surface 13C, a rear surface 13A and a right side surface 13D; It is formed as a rectangular tube having a hexagonal cross-sectional shape surrounded by a right inclined surface 13F disposed obliquely between the two.

  Thus, while providing the left inclined surface 13E between the rear surface 13A and the left side surface 13C attached to the front end side of the boom 4, and providing the right inclined surface 13F between the rear surface 13A and the right side surface 13D, the outer cylinder 13 is provided. It is the structure which can raise the buckling strength with respect to the load which acts on. On the other hand, the upper end portion 13G and the lower end portion 13H of the outer cylinder 13 are open ends.

  Reference numeral 14 denotes an upper flange plate that is located at an intermediate portion in the length direction of the outer cylinder 13 and is integrally provided on the outer peripheral side of the outer cylinder 13. One end side 42 </ b> A of a pushing rope 42 described later is locked to the upper flange plate 14. Reference numeral 15 denotes a lower flange plate integrally provided at the lower end portion of the outer cylinder 13. One end side 37 </ b> A of a support rope 37 to be described later is locked to the lower flange plate 15.

  Reference numeral 16 denotes a sheave mounting opening provided on the lower side of the outer cylinder 13. As shown in FIG. 14, the sheave attachment opening 16 is formed at a portion where the left side surface 13C and the left inclined surface 13E constituting the outer cylinder 13 intersect, and a portion where the right side surface 13D and the right inclined surface 13F intersect, An opening is formed inside the tube 13. A part of a pressing sheave 39 for pushing, which will be described later, is inserted into the sheave mounting opening 16.

  Reference numeral 17 denotes a pair of left and right boom brackets provided outside the outer cylinder 13 and below the sheave fixture 29 described later. The pair of boom brackets 17 are attached to the tip side of the boom 4. It is what Here, as shown in FIGS. 5 and 11, the pair of boom brackets 17 are formed of plates facing each other in the left and right directions, and each bracket 17 has a left and a right side of the cylindrical boom connecting portion 17A. Both sides in the right direction are fixed. The pair of boom brackets 17 are integrally fixed to the rear surface 13A of the outer cylinder 13 by means of welding or the like, and the boom connecting portion 17A of the boom bracket 17 is attached to the boom 4 using a pin 18 (see FIG. 1). Pin connected to the tip side. Further, a gap 17B is formed between the pair of boom brackets 17, and a telescopic cylinder 25 described later is arranged in the gap 17B.

  Reference numeral 19 denotes a pair of left and right cylinder brackets positioned on the upper side of the boom bracket 17 and provided outside the outer cylinder 13. The pair of cylinder brackets 19 are attached to the rod side of the excavator swing cylinder 4B. It is what Here, the pair of cylinder brackets 19 are made of plates facing each other in the left and right directions, and the rod tip of the excavator rocking cylinder 4B has a cylinder connecting portion formed by a pin hole to which the pin 20 is connected. And is integrally fixed to the rear surface 13A of the outer cylinder 13 at a position near the upper side of the boom bracket 17 by means of welding or the like. The pair of cylinder brackets 19 are pin-coupled so that the rod tip of the excavator swing cylinder 4B can be rotated using a pin 20 (see FIG. 1).

  Therefore, by extending and retracting the excavator swing cylinder 4B, the outer cylinder 13 of the extendable arm 12 swings forward, backward, upward, and downward about the pin 18 on the tip side of the boom 4. ing. The cylinder bracket 19 may be provided below the boom bracket 17 depending on the mounting position of the excavator swing cylinder 4B.

  Reference numeral 21 denotes a first-stage inner cylinder as an outermost inner cylinder accommodated inside the outer cylinder 13 so as to be movable with a suitable gap. As shown in FIGS. 11 to 14, the inner cylinder 21 is formed as a rectangular cylinder having a quadrangular cross-sectional shape surrounded by a rear surface 21A, a front surface 21B, a left side surface 21C, and a right side surface 21D. Both ends are open ends. The inner cylinder 21 is housed inside the outer cylinder 13 from the lower end portion 13H of the outer cylinder 13, and is movable in the length direction (upward and downward) with respect to the outer cylinder 13.

  Here, a slide plate (not shown) for smoothly sliding the inner cylinder 21 along the outer cylinder 13 is provided between the inner surface of the outer cylinder 13 and the outer surface of the inner cylinder 21. Yes. On the other hand, a lower flange plate 22 is provided at the lower end portion of the inner cylinder 21, and a supporting fixed sheave 35 to be described later is attached to the lower flange plate 22.

  Reference numeral 23 denotes the innermost second-stage inner cylinder accommodated inside the first-stage inner cylinder 21 so as to be movable with an appropriate gap. The inner cylinder 23 is surrounded by a rear surface 23A, a front surface 23B, a left side surface 23C, and a right side surface 23D, and is formed as a rectangular cylinder having a square cross-sectional shape that is slightly smaller than the inner cylinder 21. The inner cylinder 23 is housed inside the inner cylinder 21 from the lower end side of the inner cylinder 21 and is movable in the length direction (upward and downward) with respect to the inner cylinder 21.

  Here, a slide plate (not shown) for smoothly sliding the inner cylinder 23 along the inner cylinder 21 is provided between the inner surface of the inner cylinder 21 and the outer surface of the inner cylinder 23. Yes. On the other hand, a mounting eye 24 is provided at the lower end portion of the inner cylinder 23, and a clamshell bucket 43 described later is mounted on the mounting eye 24.

  Next, the telescopic cylinder 25 according to the present embodiment, the tube guide 26 attached to the telescopic cylinder 25, the sheave mounting guide rail 27, the sheave mounting 29, and the like will be described.

  Reference numeral 25 denotes a telescopic cylinder disposed along the length direction of the outer cylinder 13 constituting the telescopic arm 12. The telescopic cylinder 25 includes a tube 25A, a piston 25E (see FIG. 17) slidably provided in the tube 25A, one side fixed to the piston in the tube 25A, and the other side protruding outside from the tube 25A. The hydraulic cylinder includes a rod 25B.

  Here, the telescopic cylinder 25 is disposed on the rear surface 13A side of the outer cylinder 13 provided with the boom bracket 17 and at the center position in the left and right directions of the outer cylinder 13 with the rod 25B facing upward. . As shown in FIG. 8, the tip 25C of the rod 25B of the telescopic cylinder 25 is pin-coupled via a pin 25D to a bracket 13J provided in the vicinity of the upper end 13G of the outer cylinder 13.

  On the other hand, the tube 25A of the telescopic cylinder 25 extends downward as a free end and is disposed in a gap 17B formed between the boom brackets 17 paired in the left and right directions. Further, a sheave attachment 29 described later is attached to the upper side of the tube 25A. Accordingly, the tube 25A is moved along the outer cylinder 13 together with the sheave fitting 29 by expanding and contracting the telescopic cylinder 25 between the most extended state shown in FIG. 1 and the most contracted state shown in FIG. , It is configured to move downward.

  Here, when the telescopic cylinder 25 is in the most contracted state shown in FIG. 2, the length dimension (the position of the telescopic cylinder 25 in the most contracted state) from the bottom of the tube 25A to the tip 25C of the rod 25B (the position of the pin 25D). Length dimension) is L1, and the length dimension from the vicinity 13G1 of the outer cylinder 13 (position of the pin 25D where the rod 25B is connected to the outer cylinder 13) to the lower end 13H (length dimension of the outer cylinder 13) Is set to L2, the length dimension L1 of the telescopic cylinder 25 in the most contracted state is set to be approximately ½ the length dimension L2 of the outer cylinder 13.

  That is, the length dimension L1 of the telescopic cylinder 25 in the most contracted state and the length dimension L2 of the outer cylinder 13 are set in the following relationship.

  More preferably, the length dimension L1 of the telescopic cylinder 25 in the most contracted state and the length dimension L2 of the outer cylinder 13 are set to have the following relationship.

  Thus, by setting the length dimension L1 of the telescopic cylinder 25 in the most contracted state to a length dimension that is substantially ½ of the length dimension L2 of the outer cylinder 13, a large stroke of the telescopic cylinder 25 is ensured. be able to. As a result, the telescopic arm 12 can be extended to the most contracted state shown in FIG. 1 and the most extended state shown in FIG. 2 by simply hanging the telescopic rope 34 four times between the telescopic fixed sheave 31 and the telescopic movable sheave 33. It can be expanded and contracted between states.

  Reference numeral 26 denotes a tube guide provided outside the rear surface 13A of the outer cylinder 13. The tube guide 26 accommodates the tube 25A of the telescopic cylinder 25 in a movable manner. As shown in FIGS. 12 and 13, the tube guide 26 is formed by a rectangular tube having a substantially square cross-sectional shape, and is disposed in a gap 17 </ b> B formed between the pair of boom brackets 17. 13 is fixed to the rear surface 13A along the length direction. Accordingly, the tube 25 </ b> A of the telescopic cylinder 25 that has become a free end can move in the length direction of the outer cylinder 13 while being guided by the tube guide 26.

  Reference numeral 27 denotes two sheave attachment guide rails provided on the outer side of the outer cylinder 13, and each sheave attachment guide rail 27 guides a sheave attachment 29 described later. These two sheave fixture guide rails 27 are arranged one by one on the left and right sides of the rear surface 13A of the outer cylinder 13 with the telescopic cylinder 25 interposed therebetween.

  Here, the sheave fixture guide rail 27 is formed of a rectangular tube having a rectangular cross-sectional shape. The upper end portion of the sheave fixture guide rail 27 is fixed to the vicinity of the upper end portion 13G of the outer cylinder 13 via a bracket 27A, and the lower end portion of the sheave fixture guide rail 27 is adjacent to the upper flange plate 14 of the outer cylinder 13. It is fixed to the bracket via a bracket 27A. As a result, the sheave fixture guide rail 27 extends in the length direction in parallel with the rear surface 13A in a state where a fixed interval is formed between the sheave fixture guide rail 27 and the rear surface 13A of the outer cylinder 13. In this case, the strength of the outer cylinder 13 can be increased by fixing the two sheave attachment guide rails 27 made of a rectangular cylinder to the outer cylinder 13.

  Reference numeral 28 denotes a sheave mounting board fixedly provided on the upper end portion 13G of the outer cylinder 13, and the sheave mounting board 28 is attached with a telescopic fixing sheave 31 and the like to be described later. Here, the sheave mounting board 28 includes a sheave mounting portion 28A that projects from the rear surface 13A of the outer cylinder 13 to the rear side (the boom 4 side), and a rope locking portion 28B that is positioned on the front side of the sheave mounting portion 28A. Have. A fixed sheave 31 for expansion and contraction is rotatably supported by the sheave mounting portion 28A of the sheave mounting substrate 28, and one end side 34A of an expansion and contraction rope 34 described later is locked by the rope locking portion 28B.

  Reference numeral 29 denotes a sheave attaching tool attached to the tube 25A of the telescopic cylinder 25. The sheave attaching tool 29 is provided with a telescopic movable sheave 33 described later. Here, as shown in FIGS. 7, 12, and 13, the sheave attaching tool 29 is located on the upper side of the main body 29 </ b> A, the main body 29 </ b> A fixed to the upper side of the tube 25 </ b> A of the telescopic cylinder 25 An upper sheave support portion 29B that rotatably supports the telescopic movable sheave 33 and a lower sheave support portion 29C that is positioned below the main body portion 29A and rotatably supports a push-in movable sheave 41 that will be described later. Has been.

  In this case, as shown in FIG. 12, the left and right guide insertion portions of the rectangular tube shape into which the left and right sheave attachment guide rails 27 are slidably inserted into the main body portion 29A of the sheave attachment 29. 29D is provided, and the sheave fixture 29 is movable in the length direction (upward and downward) of the outer cylinder 13 while being guided by the left and right sheave fixture guide rails 27.

  A slide plate 30 is provided on the inner side surface of the tube guide 26 shown in FIGS. 11 to 13, and the tube 25 </ b> A of the telescopic cylinder 25 that has become a free end is brought into sliding contact with the slide plate 30. It is the structure which can move to the length direction of the outer cylinder 13 smoothly along.

  Next, a telescopic fixed sheave 31 and a telescopic movable sheave 33 for connecting the outer cylinder 13 constituting the telescopic arm 12, the first-stage inner cylinder 21, and the second-stage inner cylinder 23 in a telescopic manner. The telescopic rope 34, the supporting fixed sheave 35, and the supporting rope 37 will be described.

  Here, the telescopic fixed sheave 31, the telescopic movable sheave 33, the telescopic rope 34, the supporting fixed sheave 35, and the supporting rope 37 are left-right symmetrical with respect to the outer cylinder 13 with the telescopic cylinder 25 interposed therebetween. Are provided in two sets, and have the same structure. Therefore, hereinafter, the telescopic fixed sheave 31, the telescopic movable sheave 33, the telescopic rope 34, the supporting fixed sheave 35, and the supporting rope 37 disposed on the left side of the outer cylinder 13 will be described and disposed on the right side. For the components, “′” is added to the reference numerals for the corresponding components, and the description thereof is omitted.

  Reference numeral 31 denotes a telescopic fixed sheave fixed to the upper end side of the outer cylinder 13 via a sheave mounting substrate 28. The telescopic fixed sheave 31 is composed of two fixed sheaves 31A and 31B having the same diameter. Yes. One fixed sheave 31A is rotatably supported by the sheave mounting portion 28A of the sheave mounting substrate 28 via a bracket 32A, and the other fixed sheave 31B is rotatably supported by another bracket 32B. In this case, the support shafts (not shown) of the fixed sheaves 31A and 31B are arranged so as to be non-parallel to the rear surface 13A of the outer cylinder 13, respectively.

  Reference numeral 33 denotes a telescopic movable sheave that is rotatably supported by the sheave fixture 29. The telescopic movable sheave 33 is constituted by two movable sheaves 33A and 33B having the same diameter. Here, as shown in FIG. 12, one movable sheave 33A and the other movable sheave 33B are rotatable adjacent to one support shaft 33C attached to the upper sheave support portion 29B of the sheave fixture 29. It is supported by. In this case, the support shafts 33C of the movable sheaves 33A and 33B are arranged in parallel to the rear surface 13A of the outer cylinder 13. The telescopic movable sheave 33 approaches or separates from the telescopic fixed sheave 31 as the sheave mounting tool 29 moves upward and downward in accordance with the expansion and contraction of the telescopic cylinder 25.

  In this case, the telescopic movable sheave 33 supported by the sheave fixture 29 is disposed outside the left side surface 13C of the outer cylinder 13, and faces the left side surface 13C in the left and right directions with a slight gap. . Thereby, the telescopic movable sheave 33 can be prevented from projecting greatly toward the rear surface 13A of the outer cylinder 13, and the periphery of the telescopic movable sheave 33 can be reduced in size.

  Reference numeral 34 denotes an expansion / contraction rope connecting the outer cylinder 13 and the innermost inner cylinder 23, and the expansion / contraction rope 34 is constituted by a wire rope. Here, as shown in FIGS. 9 and 10, one end side 34 </ b> A of the telescopic rope 34 is locked to the rope locking portion 28 </ b> B of the sheave mounting substrate 28 provided on the upper end portion 13 </ b> G of the outer cylinder 13. The other end 34 </ b> B of the rope 34 is locked to the upper side of the inner cylinder 23 inserted inside the outer cylinder 13 and the inner cylinder 21. The middle part of the telescopic rope 34 is 4 between the two fixed sheaves 31A and 31B constituting the telescopic fixed sheave 31 and the two movable sheaves 33A and 33B constituting the telescopic movable sheave 33. It has been spun around.

  That is, the telescopic rope 34 whose one end side 34A is locked to the sheave mounting substrate 28 is one movable sheave 33A of the telescopic movable sheave 33, one fixed sheave 31A of the telescopic stationary sheave 31, and the telescopic movable sheave 33. The other movable sheave 33B and the other fixed sheave 31B of the telescopic fixed sheave 31 are wound around one by one. The other end side 34 </ b> B of the telescopic rope 34 is inserted into the outer cylinder 13 and the inner cylinder 21 from the other fixed sheave 31 </ b> B of the telescopic fixed sheave 31, and is locked to the upper side of the inner cylinder 23. .

  In this way, the telescopic fixed sheave 31 is composed of the two fixed sheaves 31A and 31B, the telescopic movable sheave 33 is composed of the two movable sheaves 33A and 33B, and the telescopic rope 34 is By hanging the fixed sheaves 31A, 31B and the two movable sheaves 33A, 33B four times, for example, as in the prior art, the telescopic rope has four telescopic fixed sheaves and four telescopic movable sheaves. Compared to a configuration in which the rope is extended eight times, the number of times that the telescopic rope 34 contacts the sheave can be halved.

  Reference numeral 35 denotes one supporting fixed sheave provided on the lower flange plate 22 of the first stage inner cylinder 21. The supporting fixed sheave 35 is rotatably supported by a bracket 36 fixed to the lower flange plate 22 of the inner cylinder 21.

  Reference numeral 37 denotes a support rope for supporting the inner cylinder 21 between the outer cylinder 13 and the inner cylinder 23, and the support rope 37 is constituted by a wire rope. Here, as shown in FIGS. 9 and 10, one end side 37 </ b> A of the support rope 37 is locked to the lower flange plate 15 of the outer cylinder 13, and a midway portion of the support rope 37 is a support fixed sheave 35. It is wound around. The other end 37 </ b> B of the support rope 37 is inserted into the inner cylinder 21 from the support fixed sheave 35 and is locked to the upper side of the inner cylinder 23 inside the inner cylinder 21.

  Next, a pushing mechanism 38 that pushes the inner cylinder 21 in the extending direction when the inner cylinder 21 is extended from the outer cylinder 13 by the telescopic cylinder 25 will be described.

  That is, reference numeral 38 denotes a pushing mechanism provided between the outer cylinder 13 and the first-stage inner cylinder 21. The pushing mechanism 38 is formed when the inner cylinder 21 is extended from the outer cylinder 13 by the telescopic cylinder 25. The inner cylinder 21 is held in an extended state.

  Here, the push-in mechanism 38 is composed of a push-in fixed sheave 39, a push-in movable sheave 41, and a push-in rope 42. The push-in mechanism 38 is symmetrical with respect to the outer cylinder 13 with the telescopic cylinder 25 interposed therebetween. Two sets are provided and have the same structure. For this reason, hereinafter, the pushing mechanism 38 disposed on the left side of the outer cylinder 13 will be described, and those disposed on the right side will be denoted by the reference sign “′”, and the description thereof will be omitted.

  Reference numeral 39 denotes a single pressing fixed sheave provided on the lower side of the outer cylinder 13. As shown in FIG. 14, the pressing fixed sheave 39 is rotatably supported by a bracket 40 fixed to the outer cylinder 13 across the sheave mounting opening 16 formed in the outer cylinder 13 via a support shaft 39A. ing. In this case, the support shaft 39 </ b> A of the push-in fixed sheave 39 is arranged with an inclination angle of the angle θ with respect to the left side surface 13 </ b> C of the outer cylinder 13. That is, the support shaft 39A of the pushing fixed sheave 39 is arranged non-parallel to the rear surface 13A of the outer cylinder 13, and a part of the pushing fixed sheave 39 supported by the support shaft 39A is part of the outer cylinder 13. It is housed inside.

  Reference numeral 41 denotes one pushable movable sheave provided on the sheave fixture 29 at a position below the movable movable sheave 33. As shown in FIG. 13, the movable movable sheave 41 for pushing is rotatably supported by the lower sheave support portion 29C of the sheave fixture 29 via a support shaft 41A. In this case, the support shaft 41 </ b> A of the pushing movable sheave 41 is disposed in parallel to the rear surface 13 </ b> A of the outer cylinder 13. The movable sheave 41 for pushing approaches or moves away from the stationary sheave 39 for pushing as the sheave mounting tool 29 moves upward and downward according to the expansion and contraction of the telescopic cylinder 25.

  Reference numeral 42 denotes a pushing rope that connects the outer cylinder 13 and the inner cylinder 21, and the pushing rope 42 is constituted by a wire rope. Here, as shown in FIGS. 9 and 10, one end side 42 </ b> A of the pushing rope 42 is locked to the upper flange plate 14 of the outer cylinder 13, and a midway portion of the pushing rope 42 is a pushing movable sheave 41. And a fixed sheave 39 for pushing. The other end side 42 </ b> B of the pushing rope 42 is inserted into the outer cylinder 13 from the pushing fixed sheave 39 and is locked to the upper side of the inner cylinder 21 inside the outer cylinder 13.

  Accordingly, when the telescopic cylinder 25 is contracted from the most extended state shown in FIGS. 1 and 9, the tube 25A of the telescopic cylinder 25 moves upward together with the sheave attachment 29, and the telescopic movable sheave 33 expands and contracts. The fixed sheave 31 is approached. Thereby, the telescopic rope 34 wound around the telescopic movable sheave 33 and the telescopic stationary sheave 31 is fed out, and the inner cylinder 23 extends downward from the outer cylinder 13 by its own weight. At this time, since the other end side 37B of the support rope 37 locked to the upper side of the inner cylinder 23 moves downward together with the inner cylinder 23, the inner cylinder 21 supported by the support rope 37 is also caused by its own weight. 13 extends downward. Thus, as shown in FIGS. 2 and 10, when the tube 25A moves to the upper limit position and the telescopic cylinder 25 reaches the minimum contracted state, the telescopic arm 12 is in the maximum extended state.

  Here, when the sheave attachment 29 approaches the telescopic fixed sheave 31, the pushing rope 42 is wound between the pushing movable sheave 41 and the pushing fixed sheave 39, and the other end side 42 </ b> B of the pushing rope 42. Moves downward along with the inner cylinder 21. Thereby, the pushing rope 42 always maintains a constant tension. Further, since the inner cylinder 21 extends while being supported by the support rope 37, the support rope 37 always maintains a constant tension.

  Therefore, when an upward excavation reaction force acts on the inner cylinders 21 and 23 by performing excavation work using the clamshell bucket 43 described later in a state where the inner cylinders 21 and 23 extend from the outer cylinder 13. However, it is possible to prevent the inner cylinders 21 and 23 from moving to the reduction side due to the tension of the pushing rope 42 and the supporting rope 37.

  Next, when the telescopic cylinder 25 is extended from the most contracted state shown in FIGS. 2 and 10, the tube 25 </ b> A of the telescopic cylinder 25 moves downward together with the sheave attachment 29, and the telescopic movable sheave 33. Is spaced from the telescopic fixed sheave 31. As a result, the telescopic rope 34 is wound between the telescopic movable sheave 33 and the telescopic fixed sheave 31, and the inner cylinder 23 moves upward and is accommodated in the inner cylinder 21. At this time, since the other end side 37B of the support rope 37 locked to the upper side of the inner cylinder 23 moves upward together with the inner cylinder 23, the inner cylinder 21 supported by the support rope 37 also moves upward. Are accommodated in the outer cylinder 13. Thus, as shown in FIGS. 1 and 9, when the tube 25A moves to the lower limit position and the telescopic cylinder 25 reaches the maximum extended state, the telescopic arm 12 is in the minimum contracted state.

  On the other hand, when the telescopic arm 12 expands and contracts between the most contracted state and the most extended state, the telescopic fixed sheave 31 ′, the telescopic movable sheave 33 ′, and the telescopic rope 34 arranged on the right side with the telescopic cylinder 25 interposed therebetween. ', The supporting fixed sheave 35', the supporting rope 37 ', the pressing fixed sheave 39', the pressing movable sheave 41 'constituting the pressing mechanism 38', and the pressing rope 42 'operate in the same manner as described above. It is.

  Here, as shown in FIGS. 13 and 14, the outer cylinder 13 has a hexagonal cross section surrounded by a rear surface 13A, a front surface 13B, left and right side surfaces 13C and 13D, and left and right inclined surfaces 13E and 13F. The movable sheave 41 for pushing has a shape and is disposed at a position facing the left inclined surface 13E in the left and right directions. For this reason, as shown by an arrow X in FIG. 13, the pushable movable sheave 41 can be disposed close to the left inclined surface 13E, and preferably the same position as the left and right side surfaces 13C and 13D, or more inward. It is good to provide in the position. In this case, the angle θ formed by the support shaft 39A of the pressing fixed sheave 39 around which the pressing rope 42 is wound between the pressing movable sheave 41 and the left side surface 13C of the outer cylinder 13 is increased. 14, as indicated by an arrow Y in FIG. 14, a part of the pushing fixed sheave 39 accommodated in the outer cylinder 13 can be sufficiently separated from the inner cylinder 21, and the pushing fixed sheave 39, the amount of protrusion from the left and right side surfaces 13C and 13D of the outer cylinder 13 at the portion exposed to the outside from the outer cylinder 13 can be reduced. As a result, it is possible to ensure a sufficient space between the pressing fixed sheave 39 and the inner cylinder 21 so as not to interfere with each other without increasing the dimension between the left and right side surfaces 13C and 13D of the outer cylinder 13. The entire telescopic arm 12 can be configured compactly. The same applies to the pressing movable sheave 41 ′ and the pressing rope 42 ′ arranged on the right side with the telescopic cylinder 25 interposed therebetween.

  Reference numeral 43 denotes a clamshell bucket that is swingably attached to an attachment eye 24 provided on the front end side (lower end side) of the inner cylinder 23. The clamshell bucket 43 is opened and closed by expanding and contracting the bucket cylinder 44 to excavate earth and sand.

  The deep excavator 1 according to the present embodiment has the above-described configuration. Hereinafter, an operation of excavating the vertical shaft 101 using the deep excavator 1 on the ground 100 to be deep excavated will be described. . The hydraulic circuit for extending and contracting the telescopic cylinder 25 will be described in detail later.

  First, as shown in FIG. 1, the deep excavator 1 extends the telescopic cylinder 25 to the maximum extent so that the telescopic arm 12 is in the minimum contracted state, and the telescopic arm 12 is perpendicular to the ground 100 on which the vertical shaft 101 is to be excavated. Hold in a proper posture.

  In this state, by contracting the telescopic cylinder 25, the tube 25A of the telescopic cylinder 25 is moved upward together with the sheave attachment 29, and the telescopic movable sheave 33 is moved closer to the telescopic fixed sheave 31. Thereby, the telescopic rope 34 wound around the telescopic movable sheave 33 and the telescopic fixed sheave 31 is fed out, and the inner cylinder 23 extends downward from the outer cylinder 13 by its own weight and is supported by the support rope 37. The formed inner cylinder 21 also extends downward from the outer cylinder 13 by its own weight.

  At this time, the pushing rope 42 is wound between the pushing movable sheave 41 supported by the sheave fitting 29 and the pushing fixed sheave 39, so that the pushing rope 42 always maintains a constant tension. Further, the support rope 37 that supports the inner cylinder 21 between the outer cylinder 13 and the inner cylinder 23 always maintains a constant tension.

  As a result, the state in which the inner cylinders 21 and 23 are extended from the outer cylinder 13 can be maintained by the tension of the pushing rope 42 and the supporting rope 37, and the clamshell bucket 43 is pushed into the bottom surface of the shaft 101. Can do. In this state, by opening and closing the clamshell bucket 43 by the bucket cylinder 44, the shaft 101 can be deeply excavated by using the clamshell bucket 43, and a large amount of earth and sand is scooped up by the clamshell bucket 43. Can do.

  After scooping up the earth and sand with the clamshell bucket 43, the telescopic cylinder 25 is extended to move the tube 25A of the telescopic cylinder 25 downward together with the sheave attachment 29, and the movable movable sheave 33 for expansion and contraction is fixed for expansion and contraction. Separate from the sheave 31.

  As a result, the telescopic rope 34 is wound between the telescopic movable sheave 33 and the telescopic fixed sheave 31, and the inner cylinder 23 moves upward and is accommodated in the inner cylinder 21. At this time, the other end side 37B of the support rope 37 that connects the outer cylinder 13 and the inner cylinder 23 moves upward together with the inner cylinder 23, so that the inner cylinder 21 supported by the support rope 37 is also It moves upward and is accommodated in the outer cylinder 13.

  As shown in FIG. 1, after the telescopic cylinder 25 reaches the most extended state and the telescopic arm 12 reaches the minimum contracted state, the distal end side of the boom 4 is lifted and the clamshell bucket 43 is pulled out from the shaft 101. And after self-propelled to the desired earth removal place by the lower traveling body 2, the earth and sand grasped by the clamshell bucket 43 are discharged to this earth removal place.

  Here, the deep excavator 1 according to the present embodiment pins the tip 25C of the rod 25B of the telescopic cylinder 25 to the bracket 13J provided on the outer cylinder 13 of the telescopic arm 12 using the pin 25D, The sheave attachment 29 for supporting the movable sheave 33 for expansion and contraction is attached to the tube 25A that has become a free end. For this reason, in order to lift the earth and sand excavated by the clamshell bucket 43 onto the ground, when the telescopic cylinder 25 is extended and the telescopic arm 12 is contracted, the heavy tube 25A and the sheave attachment 29 are brought together. Move down. Accordingly, a downward load due to the weight of the tube 25 </ b> A and the sheave attachment 29 is applied to the telescopic rope 34 wound around the telescopic movable sheave 33 and the telescopic fixed sheave 31. As a result, it is possible to increase the pulling force of the inner cylinders 21 and 23 using the weight of the tube 25A and the sheave attachment 29, and to efficiently perform the pulling operation of the inner cylinders 21 and 23 by the telescopic cylinder 25. .

  Further, in the deep excavator 1 according to the present embodiment, the telescopic fixed sheave 31 is constituted by two fixed sheaves 31A and 31B, and the telescopic movable sheave 33 is constituted by two movable sheaves 33A and 33B. The telescopic rope 34 is hung around the two fixed sheaves 31A and 31B and the two movable sheaves 33A and 33B four times. As a result, for example, as in the prior art, the life of the telescopic rope is extended compared to a configuration in which the telescopic rope is hung eight times between the four telescopic fixed sheaves and the four telescopic movable sheaves. be able to.

  Moreover, the telescopic rope 34 is hung four times between the two fixed sheaves 31A and 31B constituting the telescopic fixed sheave 31 and the two movable sheaves 33A and 33B constituting the telescopic movable sheave 33. Thus, the pulling amount when pulling up the inner cylinders 21, 23 using the telescopic rope 34 can be made four times the stroke of the telescopic cylinder 25, and the inner cylinders 21, 23 can be pulled up efficiently.

  Further, in the present embodiment, the rod 25 </ b> B of the telescopic cylinder 25 is fixed on the upper side of the outer cylinder 13 and below the telescopic fixed sheave 31. As a result, the tube 25A of the telescopic cylinder 25 to which the sheave attachment 29 is attached can be moved upward and downward within a substantially upper half range of the outer cylinder 13 extending upward and downward. For this reason, for example, as shown in FIG. 1, even when the lower half of the outer cylinder 13 goes underground when excavating the vertical shaft 101, the operator in the cab 3 </ b> B of the upper swing body 3 can extend and retract the extension cylinder 25. Therefore, the workability and safety of excavation work can be improved.

  Further, in the present embodiment, two sheave attachment guide rails 27 extending in the length direction in parallel with the outer cylinder 13 are fixedly provided on the outside of the outer cylinder 13, and the sheave attachment 29 is formed of an expansion cylinder. In accordance with the expansion / contraction of 25, it is configured to move in the length direction of the outer cylinder 13 along the sheave attachment guide rail 27.

  Accordingly, the sheave fixture 29 can be always moved on a fixed track by being guided by the sheave fixture guide rail 27. As a result, the expansion / contraction rope 34 wound around the expansion / contraction fixed sheave 31 and the expansion / contraction movable sheave 33 can smoothly follow the movement of the expansion / contraction movable sheave 33. , 23 can increase the stability of the expansion and contraction operation. Moreover, since the strength of the outer cylinder 13 can be increased by the two sheave attachment guide rails 27 fixed to the outer cylinder 13, the reliability of the entire telescopic arm 12 can be increased.

  On the other hand, the tube 25 </ b> A of the telescopic cylinder 25 to which the sheave fixture 29 is attached can also move along a certain track along the sheave fixture guide rail 27. As a result, the strength of the telescopic cylinder 25 against buckling and lateral load can be increased, and the reliability of the telescopic cylinder 25 can be increased.

  In the present embodiment, a pair of boom brackets 17 is provided on the rear surface 13A of the outer cylinder 13 on the cab 3B side of the upper swing body 3, and the pair of boom brackets 17 are attached to the distal end side of the boom 4. In addition, the telescopic cylinder 25 is disposed in a gap 17B formed between the boom brackets 17.

  Thus, the sheave attachment 29 attached to the tube 25A of the expansion cylinder 25, the expansion / contraction movable sheave 33 supported by the sheave attachment 29, the expansion / contraction fixed sheave 31 and the expansion / contraction wound around the expansion / contraction movable sheave 33. The rope 34 or the like can be directly viewed from the cab 3B side of the upper swing body 3. Thereby, the operator in the cab 3B can expand and contract the inner cylinders 21 and 23 with respect to the outer cylinder 13 while visually observing the expansion cylinder 25 and the like, and can accurately perform this expansion and contraction operation.

  The outer cylinder 13 includes a telescopic cylinder 25, a telescopic fixed sheave 31, a sheave attachment 29, a telescopic movable sheave 33, and the like on the front surface 13B opposite to the rear surface 13A on which the boom bracket 17 is provided. There is no need. For this reason, when the vertical shaft 101 is excavated, the telescopic cylinders 25 and the like do not come into contact with an obstacle and are damaged, and the workability of excavation work can be improved.

  On the other hand, as shown in FIG. 15, in order to place the deep excavator 1 in the transport posture, when the front surface 13B opposite to the rear surface 13A attached to the boom 4 of the outer cylinder 13 is placed on the ground, Without using a special table or the like, the telescopic cylinder 25, the sheave fitting 29, the telescopic fixed sheave 31, the telescopic movable sheave 33, etc. can be held in an upward posture where the weight of the telescopic arm does not act. it can.

  Therefore, when the deep excavator 1 is in the transport posture, maintenance work for the telescopic cylinder 25, the telescopic fixed sheave 31, the sheave mounting tool 29, the telescopic movable sheave 33, etc. attached to the outer cylinder 13 is performed on the ground. Since it can be performed at a close position, the workability of this maintenance work can be improved.

  In the present embodiment, a rectangular tube-shaped tube guide 26 is provided on the rear surface 13A of the outer cylinder 13, and the tube 25A of the telescopic cylinder 25 is accommodated in the tube guide 26 so as to be movable (slidable). Thereby, the tube 25A of the telescopic cylinder 25 which has become a free end can be guided in the length direction of the outer cylinder 13 by the tube guide 26, and the tube 25A to which the sheave attachment 29 is attached is smoothly moved. Can do.

  In addition, since the tube 25A of the telescopic cylinder 25 can move along a certain track along the tube guide 26, the strength of the telescopic cylinder 25 against buckling and lateral load can be increased. Moreover, by accommodating the tube 25A in the tube guide 26, the tube 25A can be protected from falling rocks or the like due to excavation work of the vertical shaft 101.

  Further, in the present embodiment, the outer cylinder 13 is formed in a cylindrical shape having a hexagonal cross-sectional shape, and the left and right sides between the rear surface 13A and the left and right side surfaces 13C and 13D attached to the distal end side of the boom 4 The right inclined surfaces 13E and 13F are provided. Thereby, the buckling strength can be increased with respect to the load acting on the outer cylinder 13 and the life of the outer cylinder 13 can be extended, so that the reliability of the entire telescopic arm 12 can be increased.

  Moreover, by disposing the movable sheave 33 for expansion / contraction outside the left side surface 13C of the outer cylinder 13, the movable sheave 33 for expansion / contraction faces the left side surface 13C of the outer cylinder 13 in the left and right directions with a slight gap. It is configured. Thus, the telescopic movable sheave 33 can be prevented from projecting greatly toward the rear surface 13A of the outer cylinder 13, and even when the telescopic movable sheave 33 having a large diameter is used, Can be miniaturized. As a result, the life of the telescopic rope 34 can be extended by using the telescopic movable sheave 33 having a large diameter.

  Thus, since the deep excavator 1 according to the present embodiment has a structure that can extend the life of the telescopic rope 34, the load acting on the telescopic rope 34 can be set large. As a result, the capacity of the clamshell bucket 43 attached to the distal end side of the inner cylinder 23 to which the telescopic rope 34 is connected can be increased, and excavation efficiency can be increased by excavating a large amount of earth and sand.

  Further, in the deep excavator 1 according to the present embodiment, the sheave mounting opening 16 is provided on the lower side of the outer cylinder 13, and a part of the pushing fixed sheave 39 is disposed inside the outer cylinder 13 through the sheave mounting opening 16. It is configured. Thereby, even when the diameter of the fixed sheave 39 for pushing is set large, the fixed sheave 39 for pushing can be compactly attached to the outer cylinder 13. As a result, the life of the pushing rope 42 can be extended by using the pushing sheave 39 having a large diameter.

  In addition, by disposing the pressing fixing sheave 39 at the position of the sheave mounting opening 16 provided on the lower side of the outer cylinder 13, it is not necessary to dispose the pressing fixing sheave at the lower end of the outer cylinder as in the prior art. . Thereby, when the inner cylinder 21 is accommodated in the outer cylinder 13, the lower flange plate 22 provided at the lower end portion of the inner cylinder 21 does not interfere with the pressing fixed sheave 39, and the lower flange plate of the inner cylinder 21. 22 can be brought close to the vicinity of the lower end portion 13H of the outer cylinder 13. As a result, the total length when the telescopic arm 12 is reduced to the minimum can be shortened, and for example, when the deep excavator 1 is transported, a compact transport posture can be achieved.

  In the above-described embodiment, of the outer cylinder 13 constituting the telescopic arm 12, the telescopic cylinder 25, the sheave mounting guide rail 27, the sheave mounting 29, the telescopic mounting on the rear surface 13A side to which the boom bracket 17 is mounted. The structure which arrange | positions the fixed sheave 31, the movable sheave 33 for expansion / contraction, etc. is illustrated. However, the present invention is not limited to this. For example, as in the modification shown in FIG. 16, the telescopic cylinder is provided on the front surface 13 </ b> B side of the outer tube 13, which is opposite to the rear surface 13 </ b> A to which the boom bracket 17 is attached. 25, a sheave mounting guide rail 27, a sheave mounting 29, a telescopic fixed sheave 31, a telescopic movable sheave 33, and the like may be arranged. Thereby, for an operator who is used to the existing telescopic arm, there is no sense of incongruity when operating the deep excavator, and the operability can be improved.

  In the above-described embodiment, the telescopic fixed sheaves 31 and 31 ′, the telescopic movable sheaves 33 and 33 ′, the telescopic ropes 34 and 34 ′, the supporting fixed sheaves 35 and 35 ′, and the supporting ropes 37 and 37. ′, The pressing fixed sheaves 39 and 39 ′, the pressing movable sheaves 41 and 41 ′, the pressing ropes 42 and 42 ′, and the like are symmetric with respect to the outer cylinder 13 with the telescopic cylinder 25 interposed therebetween. The case where two sets are provided is illustrated. However, the present invention is not limited to this, but the telescopic fixed sheave 31, the telescopic movable sheave 33, the telescopic rope 34, the supporting fixed sheave 35, the supporting rope 37, the pushing fixed sheave 39, the pushing movable sheave 41, A set of each member such as the pushing rope 42 may be provided at the center of the outer cylinder 13 in the left and right directions.

--- About hydraulic circuit ---
A hydraulic circuit for extending and contracting the telescopic cylinder 25 will be described below. FIG. 17 is a diagram illustrating an overall configuration of a hydraulic apparatus 300 including a hydraulic circuit 200 according to the present embodiment and a schematic configuration of a multistage arm drive mechanism 111 whose expansion and contraction is controlled by the hydraulic circuit 200. In FIG. 17, for convenience of explanation, the above-described multi-stage arm drive mechanism, that is, the telescopic cylinder 25, the sheave mounting tool 29, the telescopic fixed sheave 31, the telescopic movable sheave 33, and the telescopic rope 34 are provided. Simplified and partially omitted.

  The hydraulic circuit 200 includes a hydraulic pump 201, a control valve 210, a first oil passage 241, a second oil passage 242, a counter balance valve 221, a relief valve 222, a switching valve 232, and a slow return with a variable throttle. And a valve 231.

  The control valve 210 is a control valve that controls the flow of pressure oil from the hydraulic pump 201 to the telescopic cylinder 25, and the position and movement amount of the spool are changed based on the operation of an operation member (not shown) by the operator. In the present embodiment, the control valve 210 is a hydraulic pilot operated control valve, and the position of the spool and the pressure based on the pressure of the pilot pressure oil supplied by the pilot pipe lines 261 and 262 according to the operation of the operation member. The amount of movement is changed. Examples of the operation member include an operation lever and an operation pedal. The control valve 210 is switched to a contracted position (position a) for contracting the telescopic cylinder 25 based on the pressure of the pilot pressure oil supplied through the pilot pipe line 261, and the pilot pressure oil supplied through the pilot pipe line 262. Is switched to an extension position (b position) for extending the telescopic cylinder 25 and the supply of pilot pressure oil to the pilot conduits 261 and 262 is stopped by It is switched to a neutral position (c position) that prohibits the supply and return of pressure oil from the telescopic cylinder 25.

  The telescopic cylinder 25 and the control valve 210 are connected via a first oil passage 241 and a second oil passage 242. The first oil passage 241 is a first oil passage between the expansion cylinder 25 and the control valve 210 and is connected to the bottom side oil chamber 251 of the expansion cylinder 25. The second oil passage 242 is a second oil passage between the expansion cylinder 25 and the control valve 210, and is connected to the rod side oil chamber 252 of the expansion cylinder 25. Further, the control valve 210 and the hydraulic oil tank 202 are connected by an oil passage 245. In addition, oil passages 243 and 244 for guiding the pressure oil in the second oil passage 242 to the hydraulic oil tank 202 without passing through the control valve 210 are connected to the second oil passage 242. In the present embodiment, a conduit that leads to the hydraulic oil tank 202, that is, a hydraulic circuit that serves as tank pressure is referred to as a low pressure side of the hydraulic circuit 200.

  The counter balance valve 221 is provided in the first oil passage 241. The counter balance valve 221 has a built-in check valve 221 a and permits the flow of pressure oil toward the bottom side oil chamber 251 of the expansion cylinder 25. The pilot port of the counter balance valve 221 is connected to the second oil passage 242 by a pilot oil passage 221p, and the counter balance valve 221 is opened by supply of pressure oil to the second oil passage 242 (pressure increase). I speak. In the relief valve 222, the primary port 222a is connected to the oil passage between the bottom oil chamber 251 and the counter balance valve 221 in the first oil passage 241, and the secondary port 222b is connected to the second oil passage 242. Is connected. The counter balance valve 221 and the relief valve 222 are integrally provided as a valve block 220, for example, and are directly connected to the bottom side oil chamber 251 and the rod side oil chamber 252 of the expansion cylinder 25.

  The switching valve 232 is provided between the oil passage 243 and the oil passage 244, and the position is switched by the pilot pressure oil supplied to the pilot pipe 261, so that the oil passage 243 and the oil passage 244 are connected / This is a hydraulic pilot operated switching valve that shuts off. The switching valve 232 permits the pressure oil in the second oil passage 242 to escape to the low pressure side of the hydraulic circuit 200 and the pressure oil in the second oil passage 242 to the low pressure side of the hydraulic circuit 200. It is switched to a prohibition position (b position) that prohibits escape. The oil path 243 is an oil path that connects the second oil path 242 and the switching valve 232, and the oil path 244 is an oil path that connects the switching valve 232 and the hydraulic oil tank 202, and the hydraulic circuit 200 It is an oil passage which connects with the low voltage side.

  The slow return valve 231 with a variable throttle is provided in an oil path between the counter balance valve 221 and the control valve 210 in the first oil path 241. That is, the slow return valve 231 with a variable throttle is provided in series with the counter balance valve 221 and the control valve 210. Since the slow return valve 231 with a variable throttle has a built-in check valve 223a, the flow rate of the pressure oil going to the bottom oil chamber 251 of the expansion cylinder 25 is not controlled.

--- Extension stop of telescopic arm 12 ---
Next, the operation of the hydraulic circuit 200 will be described. When the operation member (not shown) is not operated by the operator, the pilot pressure oil is not supplied to the pilot pipes 261 and 262. As a result, the control valve 210 is switched to the c position. Therefore, the control valve 210 shuts off the pressure oil from the hydraulic pump 201 so that the pressure oil from the hydraulic pump 201 is not supplied to the bottom-side oil chamber 251 and the rod-side oil chamber 252, and the bottom-side oil chamber 251 and the rod Oil that returns from the side oil chamber 252 to the tank 202 via the oil passage 245 is shut off.

  The pressure oil in the bottom oil chamber 251 is blocked by the counter balance valve 221 and the control valve 210 so as not to flow out to an oil passage connected to a low pressure side such as the oil passage 244 and the oil passage 245, for example.

  Since the pilot pressure oil is not supplied to the pilot pipe 261, the switching valve 232 is switched to the position a by the biasing force of the built-in spring. Therefore, the second oil passage 242 is disconnected from the oil passage 245 by the control valve 210, but is connected to the tank 202 on the low pressure side via the oil passage 243, the switching valve 232 and the oil passage 244.

  Note that a load that contracts the rod 25 </ b> B is applied to the telescopic cylinder 25 by its own weight such as the inner cylinders 21 and 23 of the telescopic arm 12 and the clamshell bucket 43 attached to the lower end side of the inner cylinder 23. Therefore, the pressure oil in the bottom side oil chamber 251 is compressed via the piston 25E. However, as described above, the bottom oil chamber 251 is blocked from the low pressure oil passage by the counter balance valve 221. Therefore, when the operation member (not shown) by the operator is not operated, the inner cylinders 21 and 23 and the clamshell bucket 43 of the telescopic arm 12 are stopped against the gravity.

  When the boom cylinder 4A or the excavator swinging cylinder 4B described above is driven to raise the excavator 11, for example, when the telescopic arm 12 is stopped expanding and contracting, the extendable arm is used when the clamshell bucket 43 is grounded. A large load in the extending direction (downward direction) acts on 12. Therefore, a large pressure acts on the bottom side oil chamber 251 when the clamshell bucket 43 is ground. However, in the present embodiment, as described above, the primary side 222a port of the relief valve 222 is connected to the oil path between the bottom side oil chamber 251 and the counter balance valve 221, and the second oil path 242 has 2 The secondary port 222b is connected. Thereby, even if the pressure in the bottom side oil chamber 251 increases, the high pressure oil escapes to the second oil passage 242 by the relief valve 222. The pressure oil that has escaped from the bottom oil chamber 251 to the second oil passage 242 via the relief valve 222 flows out to the low pressure side of the hydraulic circuit 200 via the oil passage 243, the switching valve 232, and the oil passage 244.

--Extension of telescopic arm 12 ---
When an operating member (not shown) is operated by the operator so that the telescopic arm 12 is extended, that is, the telescopic cylinder 25 is contracted, pilot pressure oil having a pressure corresponding to the operation amount of the operating member is supplied to the pilot pipe 261. Supplied. As a result, the control valve 210 is switched to the a position, and the switching valve 232 is switched to the b position. Accordingly, the pressure oil from the hydraulic pump 201 is supplied to the rod side oil chamber 252 via the second oil passage 242 without flowing to the low pressure side of the hydraulic circuit 200 via the switching valve 232.

  When the pressure oil from the hydraulic pump 201 flows into the second oil path 242, the pressure oil from the hydraulic pump 201 acts as a pilot pressure on the counter balance valve 221 via the oil path 221 p connected to the second oil path 242. To do. As a result, the counter balance valve 221 opens while a predetermined holding pressure is applied to the bottom side oil chamber 251, and the pressure oil in the bottom side oil chamber 251 passes through the counter balance valve 221 and the slow return valve 231 with a variable throttle. Allowed to flow into. As a result, the telescopic cylinder 25 can be smoothly activated without being affected by its own weight such as the inner cylinders 21 and 23 of the telescopic arm 12 and the clamshell bucket 43.

  Since the control valve 210 is switched to the position “a”, the first oil passage 241 is connected to the oil passage 245 through the control valve 210. Accordingly, the flow rate of the pressure oil in the bottom side oil chamber 251 flows out to the low pressure side of the hydraulic circuit 200 through the counter balance valve 221 with the flow rate controlled by the slow return valve 231 with a variable throttle.

  In this embodiment, a moving pulley is used as the multistage telescopic arm drive mechanism 111, and the speed at the time of extension is increased. Therefore, the operator can select the desired arm extension speed by adjusting the variable throttle amount of the slow return valve 231 with variable throttle.

  Therefore, when an operating member (not shown) is operated by the operator so that the telescopic arm 12 is extended, that is, the telescopic cylinder 25 is contracted, the telescopic cylinder 25 is moved by the pressure oil supplied to the rod side oil chamber 252. The telescopic arm 12 is contracted and extended.

--- Contraction of telescopic arm 12 ---
When the operating member (not shown) is operated by the operator so that the telescopic arm 12 contracts, that is, the telescopic cylinder 25 is extended, pilot pressure oil having a pressure corresponding to the operation amount of the operating member is applied to the pilot pipe 262. Supplied. Thereby, the control valve 210 is switched to the b position. Therefore, the pressure oil from the hydraulic pump 201 passes through the check valve 231 a built in the slow return valve 231 with variable throttle of the first oil passage 241 and the check valve 221 a built in the counter balance valve 221. It is supplied to the bottom side oil chamber 251.

  Since the pilot pressure oil is not supplied to the pilot pipe 261, the switching valve 232 is switched to the position a by the biasing force of the built-in spring. Further, as described above, the control valve 210 is switched to the b position. Therefore, the second oil passage 242 is connected to the tank 202 via the control valve 210 and the oil passage 245, and is connected to the tank 202 via the oil passage 243, the switching valve 232 and the oil passage 244. Thereby, the pressure oil in the rod side oil chamber 252 is allowed to flow to the low pressure side of the hydraulic circuit 200 via the control valve 210 and the switching valve 232. Therefore, when the telescopic cylinder 25 is extended, the pressure oil in the rod side oil chamber 252 flows to the low pressure side of the hydraulic circuit 200 via the switching valve 232 without being affected by the back pressure by the control valve 210.

  Therefore, when an operating member (not shown) is operated by the operator so that the telescopic arm 12 contracts, that is, the telescopic cylinder 25 is extended, the telescopic cylinder 25 is moved by the pressure oil supplied to the bottom side oil chamber 251. It expands and the telescopic arm 12 is contracted.

  When the clamshell bucket 43 is raised in the ground by contracting the telescopic arm 12, even if the pressure in the bottom side oil chamber 251 rises more than necessary, the pressure oil is supplied from the relief valve 222 to the second oil. It is configured to escape to the path 242.

The hydraulic circuit 200 and the hydraulic apparatus 300 according to the present embodiment have the following operational effects.
(1) The counter balance valve 221 is provided in the first oil passage 241 connected to the bottom side oil chamber 251 of the expansion cylinder 25. The primary side port 222a of the relief valve 222 is connected to the oil path between the bottom side oil chamber 251 and the counter balance valve 221 in the first oil path 241, and the secondary side of the relief valve 222 is connected to the second oil path 242. The side port 222b is configured to be connected. In addition, the switching valve 232 is provided in the oil passage 243 branched from the second oil passage 242.

  That is, the pressure oil in the bottom side oil chamber 251 is configured to be shut off by the counter balance valve 221 and the control valve 210 that is in the neutral position (c position). Therefore, for example, even if a failure occurs in the first oil passage 241 between the counter balance valve 221 and the control valve 210, the pressure oil in the bottom side oil chamber 251 can be held by the counter balance valve 221. Even if a problem occurs in the counter balance valve 221, the pressure oil in the bottom side oil chamber 251 can be held by the control valve 210 in the neutral position (c position). Thereby, since the clamshell bucket 43 attached to the lower end side of the telescopic arm 12 and the telescopic arm 12 can be held against gravity, the reliability of the deep excavator 1 can be improved.

  When the telescopic arm 12 is extended, that is, when the telescopic cylinder 25 is contracted, the switching valve 232 is switched to the b position. As a result, when the telescopic arm 12 is extended, that is, when the telescopic cylinder 25 is contracted, the pressure oil from the hydraulic pump 201 does not flow to the low pressure side of the hydraulic circuit 200 via the switching valve 232 but passes through the second oil path 242. To the rod-side oil chamber 252. Further, the switching valve 232 is configured to be switched to the position a when the telescopic arm 12 is contracted, that is, when the telescopic cylinder 25 is expanded. Thereby, when the telescopic arm 12 is extended, that is, when the telescopic cylinder 25 is contracted, the pressure oil in the rod-side oil chamber 252 is not affected by the back pressure by the control valve 210 and the low pressure of the hydraulic circuit 200 via the switching valve 232. Flows to the side. Therefore, the back pressure acting on the pressure oil in the rod-side oil chamber 252 can be reduced and the efficiency of the hydraulic circuit 200 can be improved when the telescopic arm 12 is extended without adversely affecting the telescopic arm 12 when the telescopic arm 12 is extended. The energy efficiency of the excavator 1 can be improved.

  Even if the pressure in the bottom side oil chamber 251 increases, the pressure oil escapes from the relief valve 222 to the second oil passage 242. Thereby, for example, when the clamshell bucket 43 is raised in the ground by raising the excavator 11 by a boom raising operation or contracting the telescopic arm 12, the pressure in the bottom side oil chamber 251 is increased. Can be suppressed. Therefore, since the durability of the telescopic cylinder 25 and the counter balance valve 221 can be improved, the durability and reliability of the deep excavator 1 can be improved.

(2) A slow return valve 231 with a variable throttle is provided in the oil passage between the counter balance valve 221 and the control valve 210 in the first oil passage 241. Thereby, since the extension speed of the telescopic arm 12, that is, the contraction speed of the telescopic cylinder 25 can be set arbitrarily, the operability and work efficiency of the deep excavator 1 can be improved by setting the speed desired by the operator, for example. . Further, even if a problem occurs in the counter balance valve 221, the flow rate of the pressure oil is reduced by the slow return valve 231 with a variable throttle, and the extension speed of the extendable arm 12 is suppressed, so that the operator can easily cope with it. The reliability of the deep excavator 1 can be improved.

(3) Since the configuration of the hydraulic circuit 200 is simple and each function described above can be efficiently performed, the manufacturing cost of the hydraulic circuit 200 can be suppressed, and the reliability of the hydraulic circuit 200 can be improved. Further, the maintenance cost of the hydraulic circuit 200 can be suppressed. Therefore, the manufacturing cost and running cost of the deep excavator 1 can be suppressed, and the reliability can be improved.

  In the above description, the pressure oil from the hydraulic pump 201 acts as the pilot pressure on the counter balance valve 221 via the oil passage 221p branched from the second oil passage 242, but the present invention is not limited to this. It is not limited. For example, the pilot pressure oil supplied to the pilot pipe 261 is operated as a pilot pressure to the counter balance valve 221 by operating an operation member (not shown) so that the telescopic arm 12 extends, that is, the telescopic cylinder 25 contracts. You may comprise so that it may act.

  In the above description, the control valve 210 and the switching valve 232 are hydraulic pilot operated valves, but the present invention is not limited to this. For example, the control valve 210 and the switching valve 232 may be electromagnetically operated valves. In this case, an operation signal may be input to the switching valve 232 so that the switching valve 232 is switched to the b position by an operation signal for switching the control valve 210 to the a position.

  In the above description, the setting operation of the slow return valve 231 with the variable throttle is not particularly mentioned. For example, the slow return valve 231 with the variable throttle may be configured so that the setting operation can be performed from the cab 3B. You may comprise so that setting operation can be performed in this arrangement position.

  In the present invention, it is not essential to provide the slow return valve 231 with a variable throttle, and a slow return valve with a fixed throttle may be used. Further, the slow return valve 231 with a variable throttle need not be provided. In addition, you may combine each embodiment and modification which were mentioned above, respectively.

  Note that the present invention is not limited to the embodiment described above, and the multistage arm driving mechanism that contracts the multistage arm by extending the hydraulic cylinder and extends the multistage arm by contracting the hydraulic cylinder, and extends the hydraulic cylinder. The invention includes a multi-arm hydraulic device having various structures including the following hydraulic circuit to be contracted, and a deep excavator having various structures having the multi-arm hydraulic device. The hydraulic circuit includes an extended position for extending the hydraulic cylinder to control the flow of pressure oil to the hydraulic cylinder, a contracted position for contracting the hydraulic cylinder, and supply of pressure oil to the hydraulic cylinder and pressure from the hydraulic cylinder. A control valve that switches to a neutral position that prohibits the return of oil, a first oil passage between the bottom side oil chamber of the hydraulic cylinder and the control valve, and a rod side oil chamber of the hydraulic cylinder and the control valve. The primary side is connected to the oil path between the bottom side oil chamber and the counter balance valve in the second oil path, the counter balance valve provided in the first oil path, and the first oil path. A relief valve whose secondary side is connected to the second oil passage, a permission position that allows the pressure oil in the second oil passage to escape to the low pressure side when the hydraulic cylinder extends, and a second position when the hydraulic cylinder contracts Prohibit escape of pressure oil in the oil passage to the low pressure side And a switching valve switched to inhibition position.

2 Lower traveling body (car body)
3 Upper swing body (car body)
4 Boom 12 Multi-stage arm (Extensible arm)
13 outer cylinder 13A rear surface 13B front surface 13C left side surface 13D right side surface 13E left inclined surface 13F right inclined surface 13G upper end portion 13H lower end portion 16 sheave mounting opening 17 boom bracket 21 inner cylinder (outermost inner cylinder)
23 inner cylinder 25 telescopic cylinder 25A tube 25B rod 26 tube guide 27 sheave mounting guide rail 29 sheave mounting 31, 31 'telescopic fixed sheave 33, 33' telescopic movable sheave 34, 34 'telescopic rope 35, 35' Fixed sheave 38, 38 'Pushing mechanism 39, 39' Pushing fixed sheave 41, 41 'Pushing movable sheave 42, 42' Pushing rope 111 Multi-stage arm drive mechanism 200 Hydraulic circuit 210 Control valve 221 Counter balance valve 222 Relief Valve 231 Slow return valve with variable throttle 232 Switching valve 241 First oil passage 242 Second oil passage 300 Hydraulic device

Claims (4)

A multi-stage arm drive mechanism that contracts a multi-stage arm by extension of a hydraulic cylinder, and extends the multi-stage arm by contraction of the hydraulic cylinder;
A hydraulic circuit for extending and contracting the hydraulic cylinder,
The hydraulic cylinder has a rod end coupled to the outer cylinder of the multi-stage arm, and a sheave fitting that supports the movable sheave for expansion and contraction is attached to a tube that is a free end,
The hydraulic circuit is
An extension position for extending the hydraulic cylinder to control the flow of pressure oil to the hydraulic cylinder, a contraction position for contracting the hydraulic cylinder, and supply of pressure oil to the hydraulic cylinder and pressure from the hydraulic cylinder A control valve that switches to a neutral position that prohibits the return of oil;
A first oil passage between a bottom oil chamber of the hydraulic cylinder and the control valve;
A second oil passage between the rod side oil chamber of the hydraulic cylinder and the control valve;
A counter balance valve provided in the first oil passage , the pilot port of which is connected to the second oil passage ;
A relief valve in which a primary side is connected to an oil path between the bottom side oil chamber and the counter balance valve in the first oil path, and a secondary side is connected to the second oil path;
A permission position that permits the pressure oil in the second oil passage to escape to the low pressure side when the hydraulic cylinder extends, and the pressure oil in the second oil passage to the low pressure side when the hydraulic cylinder contracts. and a switching valve that switches the inhibition position to prohibit,
When the operation member is operated so as to contract the hydraulic cylinder, the switching valve is switched to the prohibit position, and pressure oil having a pressure corresponding to the operation amount of the operation member is supplied to the counter balance valve via the pilot port. The counter balance valve is opened by acting on the pressure oil, the pressure oil in the bottom oil chamber of the hydraulic cylinder flows out to the low pressure side of the hydraulic circuit through the counter balance valve,
When the operation member is operated so as to extend the hydraulic cylinder, the switching valve is switched to the permission position, and the pressure oil in the rod-side oil chamber of the hydraulic cylinder passes through the control valve and the switching valve. A hydraulic device for a multi-stage arm, which flows out to a low pressure side of a hydraulic circuit . The hydraulic device for a multi-stage arm according to claim 1,
The hydraulic circuit further includes a slow return valve with a variable throttle provided in series with the counter balance valve and the control valve in an oil path between the counter balance valve and the control valve in the first oil path. A hydraulic device for a multi-stage arm. A self-propelled vehicle body, a boom provided on the vehicle body so as to be able to move up and down, an outer cylinder provided to extend upward and downward on the tip side of the boom, and extendable in the longitudinal direction inside the outer cylinder A multistage arm having a plurality of inner cylinders accommodated therein, a hydraulic cylinder disposed along the length direction of the outer cylinder constituting the multistage arm, and an expansion / contraction fixed to the outer cylinder Fixed sheave for use, a sheave fitting that is attached to the hydraulic cylinder and moves in the length direction of the outer cylinder so as to approach or separate from the fixed sheave for expansion and contraction, and a movable movable for extension provided on the sheave fitting The sheave and one end side are locked to the outer cylinder and the other end side is locked to the innermost inner cylinder of the inner cylinder, and a midway portion is wound around the telescopic fixed sheave and the telescopic movable sheave Deep digging with an extended telescopic rope In the machine,
The hydraulic cylinder has a tube and a rod having one side fixed to the piston in the tube and the other side protruding outward from the tube,
With the rod of the hydraulic cylinder facing upward, the tip of the rod is attached to the outer cylinder of the multistage arm and the tube of the hydraulic cylinder is a free end,
The sheave fixture is attached to a tube of the hydraulic cylinder,
A deep excavator, further comprising the multistage arm hydraulic device according to claim 1 . The deep excavator according to claim 3 ,
The deep excavation machine characterized by attaching the front-end | tip part of the said rod of the said hydraulic cylinder to the upper part side of the said outer cylinder.

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