Attitude control device for front loader

[Detailed Description of the Invention]

(Field of the Invention) The present invention relates to the attitude control device of a front loader. (PRIOR ART) The front loader which is provided with the boom attached to vehicles enabling free rise and fall and the work tool attached to this boom enabling free rotation and with which a boom and a work tool are operated respectively independently or simultaneous by a single rocking lever is formerly common knowledge. A work tool is made to dump with this kind of front loader, and after emitting earth and sand etc., it is To (if a work tool can be grounded at a level with the ground when it is, since it moves forward immediately and earth and sand can be scooped up after grounding, it is convenient.) about earth and sand etc. to a work tool again. However, skill and time and effort are required for carrying out level grounding of the work tool by an operator's eye measurement. Then, it is while controlling a boom and a work tool by operation of a rocking lever via an electromagnetic valve, The thing which makes the electromagnetic valve N-OFF zero times, and makes a work tool hold horizontally with the electric signal from the level perception sensor of a work tool is proposed (Object of the Invention). (JP,61-221422,A) In the conventional thing, the electromagnetic valve needed to be used for control with a boom and a work tool, and there was a problem that cost increased. In order to make a work tool dump, and to carry out level grounding of the work tool after emitting earth and sand etc., in being a lowering operation position of a boom, and a work tool's having to save a rocking lever, having to hold it in an operation position and retreating vehicles simultaneously, operation operation takes skill. An object of the present invention is to solve the above-mentioned subject. (Means for solving problem) The place by which it is characterized [ of the present invention ] is provided with boom 8 attached to vehicles enabling free rise and fall, and work tool 11 attached to this boom 8 enabling free rotation, and is by single rocking lever 14, In that by which boom 8 and work tool 11 are the front loaders operated respectively independently or simultaneous, and return energization of the rocking lever 14 is carried out in the neutral position, It is lowering operation of boom 8, and work tool 11 saves, and it is to rocking lever 14 of the position of operation, Hanging object 81 engaged so that a return in the neutral position of rocking lever 14 may be regulated is established, Boom position detecting means 66 which detects whether boom 8 is in a conveyance position is established, Work tool position detecting means 51 which detects whether work tool 11 is in the relative rotating position in which level grounding is possible to boom 8 is established, and hanging object 81 and boom position detecting means 66 are, When it is detected that boom 8 is in a conveyance position, they are rocking lever 14 and hanging object 81, When it is detected by carrying out an interlocking linkage so that Conservation which regulates a return in the neutral position about boom operation of rocking lever 14 may be canceled that hanging object 81 and work tool position detecting means 51 have work tool 11 in the relative rotating position in which level grounding is possible to boom 8, they are rocking lever 14 and hanging object 81, It is on the point by which the interlocking linkage is carried out so that the engaging of clutch which regulates a return in the neutral position about work tool operation of rocking lever 14 may be canceled. (OPERATION) The earth and sand etc. which were scooped up with work tool 11 by making work tool 11 dump in the position which raised boom 8 are emitted, it is lowering operation of boom 8, and work tool 11 saves rocking lever 14 into after an appropriate time, and it carries out move operation in the position of operation. Then, rocking lever 14 engages with hanging object 81, and a return in a neutral position is regulated. Thereby, even if it lifts an operator's hand from rocking lever 14, boom 8 descends, and work tool 11 is saved and it rotates it in a direction. And if it is detected by boom position detecting means 66 that boom 8 descended to the conveyance position, the engaging of clutch which regulates a return in the neutral position about boom operation of rocking lever 14 with rocking lever 14 and hanging object 81 will be canceled. In this, boom 8 stops in a conveyance position. If it is detected by work tool position detecting means 51 that work tool 11 rotated to boom 8 to the relative position in which level grounding is possible, Conservation which regulates a return in the neutral position about work tool operation of rocking lever 14 with rocking lever 14 and hanging object 81 will be canceled. Thereby, the rotation angle to boom 8 stops work tool 11 in the state in which level grounding is possible. That is, even if which precedes by that boom 8 descends to a conveyance position, and work tool 11 rotating to boom 8 to the relative position in which level grounding is possible, boom 8 stops in a conveyance position and work tool 11 stops to boom 8 in the relative position in which level grounding is possible. A stop in the prescribed position of the above-mentioned boom 8 and work tool 11 can be performed, without an operator operating rocking lever 14, and the operator can concentrate on operation of vehicles etc. between them. If rocking lever 14 is made into the lowering operation position of A boom 8 and A boom 8 is dropped after an appropriate time, level grounding of the work tool 11 will be carried out. (EXAMPLE) Hereinafter, the example of the present invention is described based on a drawing. Drawing 4 illustrates the packet type front loader used equipping a tractor. In Drawing 4, l is the tractor body and 2 is a driver's seat. 3 is a mount and is provided in the right-and-left both sides of tractor body 1. Support 5 which 4 is a front loader and was attached to mount 3 enabling free attachment and detachment, Place 6 which it projected ahead from support 5, and was attached to the front end part of tractor body 1 enabling free attachment and detachment, A boom 8 supported pivotably by the upper end part of support 5 by axis 7 enabling free up-and-down motion, be alike at A boom cylinder 9 for moving A boom 8 up and down, and the tip of A boom 8 axis 10 -- a squirrel (it has packet (work tool) 11 which was and was supported pivotably in the direction and the dumping direction enabling free up-and-down rocking, and packet cylinder (work tool cylinder) 12 for making packet 11 rock.) Support 5, place 6, A boom 8, boom cylinder 9, and one pair of packet cylinder 12 are provided in right and left. 13 is the controls, and it is constituted, as it is attached to right-hand side support 5, and these controls 13 have one rocking lever 14 for operation and it is shown in Drawings 1 thru/or 3. In Drawings 1 thru/or 3, the A boom control valve by which 15 controls boom cylinder 9, and 16 are packet control valves which control packet cylinder 12. These control valves 15.16 are 3 position change-over valves of a spool type, and they are being fixed to tie-down plate 19 so that spool 17.18 may move in the up-and-down direction. And each spool 17*18 is energized so that it may return to a neutral position with a spring (illustration abbreviation). Tie-down plate 19 is being fixed to support 5. 20 is a control box and is being fixed to attachment vi19 in the upper part of control valve 15.16. In this control box 20, clutch style 21 for making control valve 15+16 simultaneously operational respectively independently by one rocking lever 14 is provided. clutch style 21 intersects perpendicularly -- it has 23 [ axis / 1st / axis / 2nd ] with 22. And it has the 1st rocking child 24 who can rock the 1st axis freely to the circumference of the axial center of 22, and the 2nd rocking child 25 who can rock the 2nd axis freely to the circumference of the axial center of 23, and rocking lever 14 is being fixed to the 2nd rocking child 25. Rocking lever 14 is projected from opening 27 formed in the top plate of control box 20 in the upper part. The 1st rocking child 24 is a plane view U shape, and the 1st axis of the axial center is attached [ above-mentioned ] to 22 as a horizontal direction on right-hand side. 22 [ axis / 1st ] is inserted in boss section 29 which adhered to bracket 28 of tie-down plate 19, enabling free rotation. the 1st rocking child 24 projects ahead -- an arm part 30 Wo owner is carried out, and the arm part 30 is connected with spool 17 of boom control valve 15 via pin 31, rod 32, and pin 33. The 2nd rocking child 25 is surrounded by the 1st rocking children 24, and he is supported, enabling the above-mentioned free rotation that made the axial center the direction of order according to 23 the 2nd axis. This 2nd axis 23 is supported by the 1st rocking child 24. On the left-hand side of the 2nd rocking child 25, it has the 1st axis of projection part 34 of the same axial center as 22. Projection part 34 is connected with spool 18 of packet control valve 16 via Ball bearing object 35, rod 36, and pin 37. By the above-mentioned composition, the order rocking operation to the circumference of 1st axis 22 is free for rocking lever 14, spool 17 of control valve 15 is interlocked with order [ this ] rocking, A boom 8 descends by front rocking, and A boom 8 goes up by back rocking. The right-and-left rocking operation to the circumference of 2nd axis 23 is free for rocking lever 14, spool 18 of control valve 16 is interlocked with this right-and-left rocking, packet 11 operates by left rocking in the Squeeze direction (the direction of 4th [ The ] figure Nakaya seal X), and packet 11 operates by right direction rocking in the dumping direction (the direction of 4th [ The ] figure Nakaya seal X). moreover -- rocking lever 14 is rocking to the direction of middle between the direction of order, and a horizontal direction by the 1st rocking child 24 rotating to the circumference of 1st axis 22, and the 2nd rocking child 25 rotating to the circumference of 2nd axis 23 -- it is operational. Spool 17.18 of both control valves 15.16 can be interlocked with rocking of this direction of middle, and boom 8 and packet 11 can be moved simultaneously. And with the spring for a neutral return of the above-mentioned spool 17.18, rocking lever 14 is energized so that it may return to a neutral position. Next, engaging-of-clutch implement 80 is formed in rocking lever 14 within control box 20. This engaging-of-clutch implement 80 is projected toward the method of the forward left from rocking lever 14, and that projection end is made into the hook shape which carries out downward projection. And hanging object 81 which engages with rocking lever 14 removablely via the Conservation implement 80 is established in control box 20. This hanging object 81 has the 1st hanging nail 82 for stop regulation of boom 8, the 2nd hanging nail 83 for stop regulation of packet 11, and auxiliary nail 84 located between hedge stopper claws 82.83. It is supposed that up-and-down rocking at the axis 85 center is free for wax gourd 82.83.84 respectively, and the axis 85 is supported by the top plate undersurface of control box 20 via bracket 86. the tip of auxiliary nail 84 is made into the shape of plane view Co type as shown in Drawing 3 and Drawing 5 -- this portion -- the -- it is shown also inO [ 1 ] figure thru/or Drawing 12 -- as Notch 87 of the upper part opening inserted enabling free insertion and detachment of the tip of the 1st hanging nail 82 and notch 88 of the upper part opening insertion support of the insertion and detachment of L form tip of the 2nd hanging nail 83 of is enabled are formed. Upper part energization is carried out with the spring outside a figure, and wax gourd 82.83.84 is in contact with the top plate undersurface of control box 20 via piece 89.90.91 of hanging, respectively. And as shown in Drawing 5, the tip of the 1st hanging nail 82 and the tip of the 2nd hanging nail 83 shall make an abbreviated right angle, and shall counter. Rocking lever 14 is a lowering operation position of boom 8, and engaging of clutch is carried out to the side of both nails 82.83 that make the abbreviated right angle via engaging-of-clutch implement 80 by packet 11 saving and rocking operation being carried out in an operation position. At this time, rocking lever 14 d Is in the boom lowering operation position side to neutral position N, and only d2 is turning at least side on the packet Scooping operation side. Rocking lever ■4 resists the neutral return spring of the above-mentioned spool 17.18, and it is held by engaging of clutch with this hanging object 80 in that engaging-of-clutch position. Auxiliary nail 83 makes position gap prevention with the 1st hanging nail 82 and the 2nd hanging nail 83. As shown in Drawing 2, inner 48 of push pull wire 47 is connected with the 2nd hanging nail 83. Outer Acceptance by which the end of outer 49 of push pull wire 47 was provided in control box 20 is supported by ingredient 50. Thereby, it is Argument (the 2nd hanging nail 83 carries out downward rocking at the circumference of axis 85, and release of engaging of clutch with Conservation implement 80 of it is enabled by things.) about inner 48. And the interlocking linkage of the other end of push pull wire 47 is carried out to work tool position detecting means 51. Work tool position detecting means 51 is provided with loft 53 which was supported by bracket 52 of packet 11, enabling free rocking to the circumference of bottle 53a, and was installed in accordance with boom 8 as shown in Drawing 8. It has guide cylinder 54 which holds the free end side of loft 53 slidably, cam 55 provided in loft 53, and L character-like detection arm 56. The guide cylinder 54 and detection arm 56 are supported by boom 8, enabling the free rotation to the circumference of pin 57. The end of detection arm 56 is contacted by cam 55, and packet 11 will rotate it by cam 55, if bottom 11a of packet 11 rotates on the ground relatively to boom 8 to the rotating position in which level grounding is possible. And the other end on inner the 4th of the above-mentioned push pull wire 47 is connected with the other end of detection arm 56. Outer Acceptance to which guide cylinder 54 was fixed as for the other end of outer 49 of this push pull wire 47 is attached to ingredient 58. Thereby, if packet 11 becomes a relative rotating position in which level grounding is possible to boom 8, inner 48 of push pull wire 47 will be pulled, the 2nd hanging nail 83 will for [ the bottoms ] rock with auxiliary nail 84, and engaging of clutch with engaging-of-clutch implement 80 will be canceled. If doing it so, as shown in Drawing 7, rocking lever 14 will carry out a neutral return with the neutral return spring of the above-mentioned spool 18 for packet control, and will stop rotation of packet 11. Even if engaging-of-clutch implement 80 slides to the side of the 1st hanging nail 82 and it carries out a neutral return about packet operation in the case of the neutral return about this packet operation, unless boom 8 descends to conveyance position A like the after-mentioned, maintenance of the engaging of clutch of engaging-of-clutch implement 80 and the 1st hanging nail 82 is enabled, and boom 8 continues descent. On the other hand, as shown in Drawing 2, inner 63 of push pull wire 62 is connected with the 1st hanging nail 82. As for outer Acceptance of control box 20, outer 64 of this push pull wire 62 is attached to ingredient 65. And as shown in Drawing 9, the interlocking linkage of the other end of push pull wire 64 is carried out to boom position detecting means 66. Cam 67 by which boom position detecting means 66 was attached to the back end side of boom 8, It has detection arm 68 of the shape of a bell crank supported by support 5 by axis 70 enabling free rocking, cam roller 69 provided at the tip of this detection arm 68, and a spring (illustration abbreviation) which energizes detection arm 68 so that this cam roller 69 may Contact for cam 67. Inner 63 of the above-mentioned push pull wire 62 is connected with detection arm 68, and outer Acceptance by which outer 64 of this push pull wire 62 was fixed to support 2 is attached to ingredient 71. When a level difference is provided in a contact side with cam roller 69 of cam 67 and there is boom 8 below from conveyance position A of Drawing 4, detection arm 68 rocks to the circumference of an anti-clock, and pulls inner 68. Conveyance position A is provided in a suitable position in consideration of vehicles balance, a field of view, etc. in the case of performing a tractor run. If arm 8 descends and it becomes a conveyance position by this, inner 63 of push pull wire 62 will be pulled, the 1st hanging nail 82 will for [ the bottoms ] rock with auxiliary nail 84, and engaging of clutch with engaging-of-clutch implement 80 will be canceled. If doing it so, as shown in Drawing 6, rocking lever 14 will carry out a neutral return with the neutral return spring of the above-mentioned spool 17 for boom control, and will stop descent of boom 8. Even if Conservation implement 8 * slides to the side of the 2nd hanging nail 83 and it carries out a neutral return about boom operation in the case of the neutral return about this boom operation, Unless packet 11 serves as a relative position in which level grounding is possible to boom 8 as mentioned above, maintenance of the engaging of clutch of engaging-of-clutch implement 80 and the 2nd hanging nail 83 is enabled, and packet 11 saves and continues rotation to a direction. Next, operation is explained. Since the 2nd rocking child 25 will rock to the circumference of 2nd axis 23 and will pull up spool 18 of packet control valve 16 up via projection part 34 and loft 36, if rocking lever 14 is made into a dumping operation position in the ascending position of boom 8, Packet cylinder 12 develops, and packet 11 operates in the dumping direction and emits earth and sand to the circumference of axis 10. Rocking lever 14 is made into neutral position N from the dumping state of Bucket l-11, and, subsequently to the direction side of lowering from neutral position N, it is size d and excelling, operating it and operating only size d2 in the Squeeze direction about rocking lever 14, It is a lowering operation position of boom 8, and let rocking lever 14 be a Squeeze operation position of packet 11. Then, engaging-of-clutch implement 80 is engaged from the upper part to the 1st and 2nd hanging nail 82.83, and locks rocking lever 14 in the operation position. it needs to operation of this rocking lever 14 -- since the 1st rocking child 24 of The rocks to the circumference of 1st axis 22 and depresses spool 17 of boom control valve 15 below via arm part 30 and loft 32, boom cylinder 9 contracts and boom 8 descends to the circumference of axis 7. Since the 2nd rocking child 25 rocks to the circumference of 2nd axis 23 and depresses spool 18 of packet control valve 16 below via loft 36 simultaneously, packet cylinder 12 contracts, and packet 11 saves into the circumference of axis 10, and operates to a direction. That is, packet 11 saves with downward operation of boom 8, and operation is performed simultaneously. Next, the engaging of clutch of rocking lever 14 and the 2nd hanging nail 83 with which it passes Conservation implement 80 as mentioned above when it is detected by boom position detecting means 51 that packet 11 became a relative movable position in which level grounding is possible to boom 8 is canceled, and bucket 110 rotation stops. The engaging of clutch of rocking lever 14 and the 1st hanging nail 82 with which it passes engaging-of-clutch implement 80 as mentioned above when it is detected by boom position detecting means 66 that boom 8 descended to the conveyance position is canceled, and boom 8 stops in a conveyance position. That is, if it is a position of lowering operation of boom 8, and bucket 11 saves rocking lever 14 and it is made into the position of operation, even if an operator lifts a hand from rocking lever 14, it will stop in a conveyance position and packet 11 will stop boom 8 to boom 8 in the relative rotating position in which level grounding is possible. Therefore, the operator can concentrate on operation of tractor order Advance etc. between them. Under the present circumstances, since it is made simultaneously and either precedes and stops, the stop of boom 8 and the stop of packet 11 change with an early boom ascending position, change of a hydraulic pump flow, etc. Next, since the 1st rocking child 24 will rock to the circumference of 1st axis 22 and spool 17 of boom control valve 15 will be depressed below via arm part 30 and rod 32 if rocking lever 14 is operated in the lower 4 De direction, boom cylinder 9 contracts and boom 8 descends. And since Bucket H1 has bottom 11a in a halt condition at the angle in which the ground and level grounding are possible, if packet 11 is grounded and it goes, bottom 11a will certainly ground by a horizontal state. When saving earth and sand into packet 11, rocking lever 14 is saved from neutral position N, it is operated in an operation position, packet cylinder 12 is shrunk to near the end, packet 11 is saved into the circumference of axis 10, and a direction is operated. Next, at least raising operation of boom 8 operates rocking lever 14 from neutral position N to ifU. Then, in order that the 1st rocking child 24 may rock to the circumference of 1st axis 22 and may pull up spool 17 of boom control valve 15 via arm part 30 and rod 32, boom cylinder 9 develops, and boom 8 goes up and goes. Drawings 13 thru/or 20 are applied to a different example, the same numerals show the same portion as the above-mentioned example, it omits explanation, and only a difference explains it. Hanging object 81 is tabular [ single ] and is supported by operation box 20 via guide 100, enabling free transverse direction movement. Between hanging object 81 and guide 100, ball 101 is provided via spring 102, and crevice 103 which the ball 101 inserts detachably is provided in the undersurface of hanging object 81. Blade spring 104 which presses down hanging object 81 downward is provided in operation box 20. And the opening of the hanging hole 105 to which insertion engaging of clutch of the engaging-of-clutch implement 80 of rocking lever 14 is carried out is carried out to hanging object 81. With the spring outside a figure, hanging object 81 is energized so that it may always be located in a neutral position (the [ Drawing 19 and ] about that of 20 figure WL), and the above-mentioned ball 101 and crevice 103 are engaged, and it is positioned in this neutral position. When this hanging object 81 is in a neutral position, engaging-of-clutch implement 80 is above hanging hole 105, and has become a Conservation released state. And in hanging object 81, it is with inner 63 of boom position detecting means 66, the interlocking linkage of the inner 48 of packet position detecting means 51 is carried out -- boom 8 -- hanging object 81 is pulled in the direction of boom lowering rather than a neutral position by inner 63 from conveyance position A in the upper part When there is no packet 11 in the relative rotating position in which level grounding is possible to boom 8, it is being pulled in the packet Scooping direction by inner 48. And when hanging object 81 is not located in a neutral position, If rocking lever 14 is made into the lowering operation position of boom 8, and packet 11 saves in the state of Drawing 13 and Drawing 14 and it is an operation position since hanging object 81 has run aground on ball 101, as shown in Drawing 15 and Drawing 16, engaging-of-clutch implement 80 will engage with hanging hole 105. And if it is detected by packet position detecting means 51 that packet 11 became a relative rotating position in which level grounding is possible to boom 8, inner 48 will loosen and rocking lever 14 will return to a neutral position about packet operation like the 17th illustration. If boom 8 having descended and having become conveyance position A is detected by boom position detecting means 66, inner 63 will loosen and rocking lever 14 will return to a neutral position about boom operation like the 18th illustration. And if both inners 48.63 of both loosen, it will return to the neutral state of Drawing 19 and Drawing 20, and both boom 8 and packet 11 will stop. Cam 55.67 shape is made into specified shape so that inner 48.63 may loosen in a prescribed position. Other composition and an operation are the same as that of the above-mentioned example. Drawing 21 is applied to a comparative example and the point of making hanging object 81 engaging and releasing spool 17*18 instead of rocking lever 14 has the difference with the above-mentioned example. That is, the piece 111 of the 1st engaging of clutch is provided in the tip perimeter of spool 17 for boom control, and the piece 112 of the 2nd engaging of clutch is provided in the tip perimeter of spool 18 for packet control. Hanging object 81 is formed by the piece 113 of the 1st hanging, and the piece 114 of the 2nd hanging, and rocking of each piece 113,114 of hanging is enabled at the circumference of axis 115*116. And if rocking lever 14 is made into the lowering operation position of boom 8 and spool 17 is depressed below, the piece 113 of the 1st hanging will engage with the piece 111 of the 1st Conservation, and will regulate the neutral return of spool 17. Therefore, the piece 113 of the 1st hanging is regulated [ rocking in the engaging-of-clutch release direction (the direction of the circumference of the left in the figure) with the piece 111 of the 1st engaging of clutch, and ] with the spring outside a figure from the state of illustration. If Bucket l-11 saves, rocking lever 14 is made into an operation position and spool 18 is depressed, the piece 114 of the 2nd hanging will engage with the 2nd Conservation implement 112, and will regulate the neutral return of spool 18. Therefore, the piece 114 of the 2nd hanging is regulated [ rocking in the Conservation release direction (the direction of the circumference of figure Nakamigi) with the piece of the 2nd engaging of clutch, and ] with the spring outside a figure from the state of illustration. And the interlocking linkage of the piece 113 of the 1st hanging is carried out to boom position detecting means 66 via push pull wire 62, If boom 8 serves as conveyance position A, inner 63 will be pulled, the piece 114 of the 1st hanging is rocked in the engaging-of-clutch release direction with the piece 111 of the 1st engaging of clutch, a neutral return is carried out and spool 17 stops boom 8. The interlocking linkage of the piece 114 of the 2nd hanging is carried out to packet position detecting means 51 via push pull wire 47, If bucket eye 1 becomes a relative rotating position in which level grounding is possible to boom 8, inner 48 will be pulled, the piece 114 of the 2nd hanging is rocked in the engaging-of-clutch release direction with the piece 112 of the 2nd engaging of clutch, a neutral return is carried out and packet 11 suspends spool 18. In order to make spool 17.18 engage and release hanging object 81 in the case of this comparative example, processing of providing piece 111.112 of engaging of clutch is required, but it is not preferred to give such processing to the parts of that of which processing accuracy is required like control valve 15.16. It is if it is going to make it engage with hanging object 81 only when in the case of this comparative example rocking lever 14 is boom lowering operation and it becomes a position of packet Scooping operation, The composition of applying rocking regulation power to rocking lever 14 is required so that an additional stroke region may be provided in the direction of boom lowering, and the packet Scooping direction and usually bigger control force than operation may need for the operation stroke region of usual rocking lever 14 in this additional stroke region, and composition becomes complicated. (EFFECT OF THE INVENTION) According to the present invention, it is not necessary to use an electromagnetic valve for control with a boom and a work tool, and cost can be reduced on the occasion of level grounding control of a work tool, and a hand can be lifted from a rocking lever, vehicles operation can also be performed, and skill is not needed for operation operation.

[Brief Description of the Drawings]

It is a sectional side elevation in which Drawings 1 thru/or 12 are applied to the 1st example of the present invention, and Drawing 1 shows the inside of a control box, In the flat section and Drawing 4, the back sectional view and Drawing 3 are [ Drawing 2 ] side views of a tractor with a front loader, The top view of the hanging object in the state where Drawings 5 thru/or 7 differed, respectively, and Drawing 8 are side views of a packet position detecting means, Drawing 9 is a side view of a boom position detecting means, and Drawing 10 is I Arrow view figure of Drawing 5, Drawing 11 is ■ Arrow view figure of Drawing 5, and Drawing 12 is ■ Arrow view part sectional view of Drawing 5, Drawings 13 thru/or 20 are applied to the 2nd example of the present invention, and Drawing 13 is a top view of a hanging object, It is a sectional side elevation showing the inside of the control box which the top view in the state where Drawing 14 differed in the sectional side elevation, and Drawing 15 differed in the hanging object, the top view in the state where, as for the sectional side elevation and Drawings 17 or 19, Drawing 16 further differed in the hanging object, respectively, and Drawing 20 are applied to the sectional side elevation of Drawing 19, and requires Drawing 21 for a comparative example. 8-boom, 11 .. - work tool, 14-rocking lever, 51 and - work tool position detecting means, 66, - and a boom position detecting means. Applicant for a patent Kubota, Ltd. The 5th Figure The Drawing 6 The 78th Figure