JP4626746B2 - Combine and harvesting method with combine - Google Patents

Description

  The present invention relates to a combine and a mowing method for moving a weeding device and a pulling device with respect to a cutting blade (conveying device) to enable harvesting of a cocoon at the time of cutting.

Conventionally, a plurality of lug-type pulling devices that cause grain husks are arranged in parallel behind a plurality of weeding tools arranged side by side at the foremost position, and a cutting blade is provided on the rear side of the pulling device. Has been disclosed which raises the rotation center provided above the cutting blade so that the cereals close to the cocoon can be cut (see Patent Document 1).
JP 2004-24112 A

In the known example, since the weeding tool and the pulling device are simply raised with respect to the kite, there is a problem that the position of the center of gravity of the body moves extremely forward.
In particular, when the machine body, such as over a heel, is in a forward-tilt posture with a forward-lowering position, there is a problem that the cutting blade thrusts into the field.
The present application is devised so as to realize the harvesting of the cocoon on the heel with a stable body posture.

The present invention includes a plurality of weeding devices 8 arranged side by side at the foremost position, a pulling device 9 for causing a plurality of wheat straws arranged in the rear of the weeding device 8, and a rice cake on the rear side of the pulling device 9 A cutting part 4 having a cutting blade 10 for cutting the cutting blade 10 and a conveying device 11 provided behind the cutting blade 10 is provided in the front part of the body frame 1, and the cutting part 4 is connected to the cutting frame 18 of the cutting part 4. left right intermediate position of the lower frame 19 reaper of, attaching a leading end of Tate支 lifting frame 20 mounted for vertical rotation support base 21 provided on the body frame 1 side in a fixed state, reaper lower The lower parts of the left and right side frames 27 are fixedly attached to both the left and right sides of the frame 19, and the bases of the lower front and rear frames 28 arranged in parallel on the left and right sides so as to protrude forward are fixedly attached to the lower cutting frame 19 , leading ends of the lower longitudinal frame 28 the cutting blade 10 Linking fixed by cutting blade frame 29 mounted sliding freely, constitutes a fixed frame 24 the reaper and the lower frame 19 by the left and right side frames 27 and the lower longitudinal frame 28 and the cutting blade frame over arm 29, the cause lower ink case 31 of the device 9 is mounted in a fixed state to a separatory grass rod 30 before Symbol min grasses device 8, the rear portion of each minute grass rod 30 is connected by a movable-side lateral frame 36 in the lateral direction, each of the inking device the vertical transfer movement cylinder 37 provided above the cause case 31 9, only attached to the fixed state the top of each transmission cylinder 37 in the lateral direction of the upper transmission case 38, partial grass rod 30 and the upper transmission case 38 a and cause case 31 for connecting the two and moving side lateral frame 36 for connecting the respective partial grass rods 3 0 constitute a movable frame 25, provided with the cutting frame over arm 18 in the vertical support frame 20 side Said fixed frame For the 4 and the stationary frame 24 divided form into the moving frame 25 moves, constitutes a cause unit 26 is provided at least partial grasses device 8 and causes device 9 to the mobile frame 25 side, the movable frame 25 is the about the rotational center S provided on the upper any fixed part of the fixed frame 24 as the axis of the upper transmission case 38 by upward pivoting, on a minute grasses device 8 and causes device 9 on the body traveling direction together to open the front side of the cutting blade 10 is rectangular rotates, a structure in which the center of gravity G of the moving frame 25 is positioned above the rear side than the rotation center S, the upper transmission case 38 and the left and right side frames 27 the mounting portion or the vicinity thereof, the cause unit position detecting means 40 for detecting the position of the moving frame 25 is provided, the cited electromotive unit position detecting means 40, the upper transmission case 38 circularly The rotary member 41 of the shape provided, the switch 42 to either one of the fixed portion of the rotary member 41 and the left and right side frames 27 provided, before SL switch to the other of the fixed part of the rotating body 41 horizontally side frames 27 a plurality of the abutting member 43 abuts configuration and then provided to the 42, to the causing unit 26 lowers the obstacle detection hand stage 44 of the ultrasonic sensor type for detecting the position of the obstacle in front of the the cited electromotive unit 26 The combine is configured to automatically rotate the pulling unit 26 upward when the obstacle detecting means 44 detects that the pulling unit 26 has approached the obstacle for a certain distance or more. In a place away from the cocoon, the combine is moved forward, and the weeding device 8 is used for weeding, and the pulling device 9 is used to raise the harvester. Then, the root side of the cereal is cut, and the cut cereal is transported by the cereal transporting device 11 to harvest the cereal.
At the time of cutting, the weeding device 8 and the pulling device 9 are lifted so that their center of gravity G is located closer to the center of the machine body than the rotation center S, and the cutting blade 10 is faced to the root side of the cereal and cut. Then, the cut cereals are transported by the cereal transporting device 11 to harvest the cereals.

  According to the first aspect of the present invention, the harvesting operation can be performed with the stable body posture of the cocoon at the end of the cocoon, and the operation of over the culm can be performed stably.

An example of a combine that can carry out the method of the present invention will be described with reference to the drawings. Reference numeral 1 denotes an airframe (FIG. 2), 2 a traveling device provided at a position below the airframe 1, and 3 at an position above the airframe 1. The provided threshing device, 4 is a cutting part provided on the front side of the threshing device 3, 5 is a glen tank, 6 is a discharge auger for discharging the grains in the glen tank 5, and 7 is a control unit.
The mowing unit 4 has a weeding device 8 arranged side by side at the most advanced position, and a pulling device 9 that raises the cereals weeded by the weeding device 8 on the rear side of each weeding device 8. A cutting blade 10 is provided on the rear side of the device 9, and a culm transporting device 11 that transports the culm cut by the cutting blade 10 from above the cutting blade 10 is provided.

Although the configuration of the cereal conveying device 11 is arbitrary, for example, a lag-type front conveying device 12 that conveys the harvested corn flour is provided on the rear side of the cutting blade 10, and below the end portion of the front conveying device 12. Is provided with a star-foil-shaped scraping device 13 suspended from the front transport device 12, and the cereals transported by the front transport device 12 and the scraping device 13 are transported to the rear side of the front transport device 12 and the scraping device 13. The rear transfer device 14 and the tip transfer device 15 provided above the rear transfer device 14 are provided.
In addition, the rear transport device 14 is configured to be movable up and down at its starting end so that it can also be used as a handling depth adjusting transport device. The rear end of the rear transport device 14 is used as the starting end of the cereal supply and transport device 16. However, it is also possible to provide a handling device for adjusting the working depth or a take-up transport device.
Further, the cereal conveying device 11 may include a handling depth adjusting conveying device or a take-up conveying device, and the scraping device 13 may be excluded from the cereal conveying device 11, depending on the name or the like. It is not limited.

Thus, the cutting unit 4 attaches the cutting lower frame 19 of the cutting frame 18 to the distal end of the vertical support frame 20, and the base of the vertical support frame 20 is freely rotatable on a support base 21 provided on the body frame 1 side. And attach to the body frame 1 side. The tip of the cutting upper and lower cylinders is attached to the vertical support frame 20, the base of the cutting upper and lower cylinders is attached to the body frame 1, and the cutting upper and lower cylinders are extended and lowered to move the cutting part 4 up and down.
In this case, the cutting frame 18 is divided and formed into a fixed frame 24 provided on the vertical support frame 20 side and a moving frame 25 that moves relative to the fixed frame 24, and at least the weeding device 8 and the lifting mechanism are formed on the moving frame 25 side. The pulling unit 26 is configured by providing the apparatus 9, and the pulling unit 26 (moving frame 25) is rotated upward in the forward direction about the rotation center S provided at the upper arbitrary fixed portion of the fixed frame 24, and the moving frame 25 (pulling) The center of gravity G of the unit 26) is configured to be located on the rear side above the rotation center S (from the center of the machine body) (for example, FIGS. 7 and 10).

That is, the vehicle body after the entrance to the field or over the ridge is in a forward tilted posture or the gravity center position of the vehicle body is extremely forward, but the gravity center G of the moving frame 25 (the pulling unit 26) is above the rotation center S. In a state of being stabilized by being positioned on the rear side, the cutting unit 4 moves the front side portion (the pulling unit 26) of the cutting unit 4 positioned in front of the cutting blade 10 with respect to the cutting blade 10, and the edge (pillow) Ground) The cutting blade 10 can approach the cedar of M directly and cut it.
Further, since the pulling unit 26 on the front side of the cutting blade 10 is moving upward, the lower portions of the weeding device 8 and the pulling device 9 are prevented from being pushed into the field.

  Thus, an example of opening the front side of the cutting blade 10 is shown. The front end of the vertical support frame 20 is fixedly attached to the middle position of the cutting lower frame 19 of the cutting frame 18 and the cutting lower frame is fixed. The lower parts of the left and right side frames 27 are fixedly attached to both the left and right sides of the frame 19, and the lower front and rear frames 28 are fixedly attached to the lower cut frame 19 so as to protrude forward. Are arranged in parallel on the left and right sides, and the front end side of the lower front and rear frame 28 is connected and fixed by a cutting blade frame 29, and the cutting blade 10 is slidably attached to the cutting blade frame 29 (attachment of the cutting blade 10) The configuration that slides left and right is well known, and details are omitted).

As described above, the cutting lower frame 19, the left and right side frames 27, the lower front and rear frames 28, and the cutting blade frame 29 constitute a fixed frame 24.
Each weeding device 8 is provided at the front end of a weed rod 30 formed in the shape of a shaft rod in the front-rear direction, and each weeding device 8 is a known one and has an inclined surface that becomes higher as it goes rearward in a side view. Formed.
The pulling device 9 may have a known configuration. For example, the driving gear 33 is provided on the upper portion of the pulling case 31 of the pulling device 9 by a horizontal shaft 32 in the front-rear direction, and the driving gear 33 and a roller (not shown). A chain (not shown) in which a plurality of pulling lugs 35 are undulated is hung between the pulling lug 35 and the pulling lug 35 is raised at a lower position of the pulling case 31 to raise the cereal and a predetermined upper position of the pulling case 31 Stored in the pulling case 31 and descending, and this may be repeated to cause the cereals, but separately in the front-rear direction crossing the pulling lug 35 around the horizontal axis in the left-right direction. A rotating lug (spreading) lug may be provided as long as it can cause weeding following the weeding device 8.

The pulling case 31 of the pulling device 9 is fixedly attached to the front and rear intermediate portions of the lower weed basket 30 among the plurality of split weed baskets 30, and the rear part of each weed basket 30 is in the horizontal direction. It is connected by the moving side horizontal frame 36, and the rear part of the weed ridge 30 is made to face above the cutting blade 10.
A transmission cylinder 37 protruding upward is provided on the upper part of the pulling case 31 of each pulling device 9, and the upper part of each transmission cylinder 37 is fixedly attached to an upper transmission case 38 constituted by a horizontal cylinder member.
Accordingly, the moving frame 25 includes at least a weed ranch 30, an upper transmission case 38, a pulling case 31 that couples both of them, and a moving side frame 36 that connects each weed ranching 30. Both the left and right sides of the case 38 are rotatably attached to a suspension base 39 that supports the rotation of the upper part of the left and right side frame 27 (FIG. 4), and the weeding device uses the axis of the upper transmission case 38 in the left and right direction as the rotation center S. 8 and the pulling device 9 are configured to rotate upward in the airframe traveling direction to open the front side of the cutting blade 10.

In this way, the moving frame 25 rotates the weeding device 8 and the pulling device 9 upward in the direction of travel of the body with the shaft center of the upper transmission case 38 in the left-right direction as the rotation center S. By changing the height of the lower part of 9 variously, the pulling-up action of the fallen corn straw is made effective, and it is suitable.
In this case, as shown in FIGS. 11 and 12, the rear portion of each weed ridge 30 is raised on the back side of the pulling case 31 and fixed to the transmission cylinder 37, and the connection by the moving side lateral frame 36 is omitted. It is possible to prevent the cereal grains from interfering with the moving side lateral frame 36, which is preferable.

  Thus, at the attachment portion of the upper transmission case 38 and the left and right side frames 27 or in the vicinity thereof, the pulling unit position detecting means 40 for detecting the position of the moving frame 25 (the pulling unit 26) is provided (FIGS. 13 and 14). . The pulling unit position detection means 40 of the embodiment is provided with a disk-shaped rotating body 41 in the upper transmission case 38, a switch 42 is provided in one of the fixed portions of the rotating body 41 and the left and right side frames 27, and the other A contact member 43 that contacts the switch 42 is provided. When a plurality of contact bodies 43 are provided, a plurality of heights of the weeding device 8 can be selected.

Thus, the pulling unit 26 is provided with obstacle detecting means 44 for detecting the position of the obstacle in front of the pulling unit 26, and the obstacle detecting means 44 makes the pulling unit 26 become an obstacle (畦) over a certain distance. When approached, the pulling unit 26 is configured to automatically rotate upward (FIG. 15).
In this case, a changeover switch for switching on and off the automatic ascent control by the obstacle detection means 44 is provided, and only when it is turned on by the changeover switch, it is automatically raised.
If the change-over switch is turned on at the time of pillow trimming, the pulling unit 26 is automatically rotated upward when approaching the bag more than a certain distance, improving operability and workability.
Moreover, it transfers in the state which followed the normal trimming work from the pillow trimming work, and this improves the operativity and workability | operativity.
In the embodiment, an ultrasonic sensor is provided in the weeding device 8 to constitute the obstacle detecting means 44.

Further, a plurality of obstacle detection means 44 are arranged in the vertical direction (FIG. 16), and the pull-up unit 26 is rotated upward according to the height of the obstacle (hook). Therefore, operability and workability are improved.
That is, if the setting of the raising height of the pulling unit 26 is fixed to a predetermined height, a loss occurs because the pulling unit 26 is raised to the predetermined height even when the height is low, but this loss is generated. Therefore, operability and workability are improved.

Therefore, the pulling device 9 is provided with a stand 47, and the stand 47 is configured to be switchable between a support position for supporting the pulling unit 26 raised to a predetermined height and a retracted position (FIG. 17). In the embodiment, the stand 47 is formed in the shape of a vertical shaft, the lower portion of the stand 47 is rotatably attached to the reinforcing frame 48 of the pulling case 31, and the upper portion of the stand 47 is attached to the holder 49 provided on the upper portion of the pulling case 31. Engage and store.
Since the stand 47 is provided on the back surface of the pulling case 31, there is no hindrance to the cutting operation, and the stand 47 supports the pulling unit 26 raised to a predetermined height, so that the pulling unit 26 is securely held and does not descend. Work safely.

20 and 21 show another embodiment of the stand 47. The upper portion of the stand 47 is rotatably attached to an arbitrary position between the upper and lower sides of the right side frame 27. The stand 47 is a side portion. Engage with a holder 49 provided on the frame 27 for storage. An engagement hole 50 is provided at the tip of the stand 47, and the engagement hole 50 is configured to engage with a hook 51 provided on the back surface of the pulling case 31 or the transmission cylinder 37.
The stand 47 supports the pulling unit 26 by raising the pulling unit 26 to a predetermined height and engaging the engaging hole 50 of the stand 47 removed from the holder 49 with the hook 51 provided in the pulling device 9. If the pulling unit 26 is simply raised, the pulling unit 26 may slowly drop due to its own weight, but the stand 47 supports the pulling unit 26 and can be easily maintained. Further, the stand 47 supports the pull-up unit 26 by the engagement of the engagement hole 50 and the hook 51, so that the support is surely supported.

Accordingly, a moving mechanism 53 for moving (turning) the moving frame 25 is provided at the attachment portion of the upper transmission case 38 and the left and right side frames 27. The moving mechanism 53 is configured by providing a moving drive means 54 at the upper part of the left and right side frames 27 and meshing a gear 55 of the moving drive means 54 with a passive gear 56 provided on the outer periphery of the upper transmission case 38.
In this case, the movement drive means 54 of the movement mechanism 53 is constituted by a motor with a brake mechanism, and the rotation (rotation) of the upper transmission case 38 is locked by the movement mechanism 53 when the movement drive means 54 is not energized. This is preferable because the operation of the stand 47 is facilitated.
A passive pulley 58 is provided on a transmission shaft 57 provided in the upper transmission case 38, and the belt 60 is wound around the passive pulley 58 and the output pulley 59 provided on the side frame 27.
However, a lock device may be separately provided between the fixed frame 24 and the moving frame 25.

(Operation of Example)
When the traveling device 2 travels through the field, the weeding device 8 of the cutting unit 4 weeds the cereals in the field, and the sown cereals are caused by the pulling device 9, and the induced cereals become the cutting blade 10. The cereals are transported to the cereal supply / transport device 16 by the cereal transporting device 11, and the cereals are supplied to the threshing room by the cereal supply / transport device 16 and threshed.
The cutting unit 4 is configured by providing a weeding device 8, a pulling device 9, a cutting blade 10, and a culm transporting device 11 on a cutting frame 18, and the cutting frame 18 is attached to the tip of a vertical support frame 20. Since the base of 20 is rotatably attached to a support base 21 provided on the body frame 1 side, when the cutting upper and lower cylinders are expanded and contracted, the cutting unit 4 can be moved up and down, thereby moving the entire cutting unit 4 up and down. And adjust the cutting height to move forward.

  Thus, the cutting frame 18 of the cutting unit 4 is provided with at least the weeding device 8, the pulling device 9, the cutting blade 10, and the culm transporting device 11, and the entire cutting frame 18 moves up and down with respect to the body frame 1. The cutting frame 18 is divided into a fixed frame 24 provided on the vertical support frame 20 side and a moving frame 25 that moves relative to the fixed frame 24. At least the weeding device 8 and the pulling device 9 are provided on the moving frame 25 side. And the moving frame 25 (the pulling unit 26) has a center of gravity G of the moving frame 25 (the pulling unit 26) around the rotation center S provided at the upper arbitrary fixed portion of the cutting unit 4. Since it is configured to rotate upward in the front direction until it is positioned in the rear side above the rotation center S, the front portion (the pulling unit) of the cutting portion 4 positioned in front of the cutting blade 10 is configured. The cutting blade 10 can be moved forward to the initial position by moving the tool 26) upward with respect to the cutting blade 10, and the cutting blade 10 is moved as close as possible to the cocoon of the cutting heel, and the knives are not subjected to manual work. (Headland) M cereals can be machined and the moving frame 25 (the pulling unit 26) can be used even when the forward tilting posture after entry to the field or over the straw and the center of gravity of the machine body are extremely forward. And the work can be done in a state where the center of gravity of the aircraft is stabilized.

Further, since the pulling unit 26 on the front side of the cutting blade 10 is moving upward, the lower portions of the weeding device 8 and the pulling device 9 are prevented from being pushed into the field.
In this case, since the weeding device 8 and the pulling device 9 arranged in parallel are integrally formed in the pulling unit 26, when the pulling unit 26 is moved, the entire front of the cutting blade 10 is opened at one time and opened. Make work easier.
Further, since the weeding device 8 and the pulling device 9 are moved together with the moving frame 25 (the pulling unit 26), the worker at the control unit 7 performs the cutting operation of cutting the cutting blade by approaching directly to the culm at the shore. 10 and its front upper upper periphery, which is preferable because it improves workability and operability.
In this case, the culm conveying device 11 exists from the upper side to the rear side of the cutting blade 10, and the culm conveying device 11 is not only provided in a fixed position on the fixed frame 24 together with the cutting blade 10, but also moved the pulling unit 26. Since it can be driven later, the cereals harvested by the cutting blade 10 are transported to the cereal supply transport device 16 by the cereal transport device 11 and supplied to the threshing chamber by the cereal supply transport device 16.

  Thus, when the moving drive means 54 is energized to rotate the gear 55, the passive gear 56 is rotated by the rotation of the gear 55, the passive pulley 56 rotates the upper transmission case 38, and the upper transmission case 38 is moved to the moving frame. 25 (the pulling unit 26) as a whole is rotated upward about the rotation center S provided between the upper transmission case 38 and the left and right side frames 27, and the front side of the cutting blade 10 is opened.

The side view of a combine. The side view of a cutting part. FIG. The perspective view which raised the raising unit to predetermined height. Side view of the pulling unit (the weed body is omitted). Front view (omitted from weeds). The side view which raised the pulling unit so that the gravity center G may turn closer to the center of the body from the rotation center S. The front view. The side view which moved up the raising unit to predetermined height. A side view of getting over the kite. Explanatory drawing of the state which sets a raising unit to various height, and performs a cutting work. The perspective view of the state which raised the raising unit to the predetermined height in the Example of FIG. The side view which provided the position detection means of the raising unit. The side view of a raising unit position detection means. The perspective view which provided the obstruction detection means. The perspective view of the other Example of an obstruction detection means. The perspective view of the Example which provided the stand which supports a raising unit. The front view. The perspective view of the holder. The front view of the other Example of a stand and the perspective view of a stand and a holder. FIG. Explanatory drawing which shows the thrust of a cutting part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Airframe frame, 2 ... Traveling device, 3 ... Threshing device, 4 ... Cutting part 4, 5 ... Glen tank, 6 ... Discharge auger, 7 ... Steering unit, 8 ... Weeding device, Pulling device 9 ... Pulling device, 10 DESCRIPTION OF SYMBOLS ... Cutting blade, 11 ... Grain conveying device, 12 ... Front conveying device, 13 ... Scratching device, 14 ... Rear conveying device, 15 ... Ear tip conveying device, 16 ... Grain supply / conveying device, 18 ... Cutting frame, 19 ... lower cutting frame, 20 ... vertical support frame, 21 ... support base, 24 ... fixed frame, 25 ... moving frame, 26 ... pulling unit, 27 ... left / right side frame, 28 ... lower front / rear frame, 29 ... cutting blade Frame, 30 ... Weeding fence, 31 ... Pulling case, 32 ... Horizontal shaft, 33 ... Driving gear, 35 ... Pulling lug, 36 ... Moving side horizontal frame, 37 ... Transmission cylinder, 38 ... Upper transmission case, 40 ... Pulling unit Position detecting means, 41 ... rotating body, 4 DESCRIPTION OF SYMBOLS ... Switch, 43 ... Contact body, 44 ... Obstacle detection means, 47 ... Stand, 48 ... Reinforcement frame, 49 ... Holder, 50 ... Engagement hole, 51 ... Hook, 53 ... Moving mechanism, 54 ... Motor for movement, G: Center of gravity, S: Center of rotation.

Claims (1)

A plurality of weeding devices (8) arranged side by side at the forefront position, a pulling device (9) for causing a plurality of juxtaposed grains behind the weeding device (8), and a rear of the pulling device (9) A cutting portion (4) having a cutting blade (10) for cutting the side grain and a conveying device (11) provided at the rear of the cutting blade (10) is provided at the front portion of the body frame (1) ; The reaping part (4) is provided at a left and right intermediate position of the reaping lower frame (19) in the reaping frame (18) of the reaping part (4). the tip of the vertical support frame mounted for vertical pivots 21) (20) attached to the fixed state, reaper mounted lower in a fixed state of the left and right side frames (27) on the left and right sides of the lower frame (19) lower front and rear frame to the lower frame (19) cutting a plurality of juxtaposed in the lateral side so as to protrude forward (2 8) is attached in a fixed state, and the tip side of each lower front and rear frame (28 ) is connected and fixed by a cutting blade frame (29) to which a cutting blade (10) is slidably attached , and the cutting lower frame (19), the left and right side frame (27), the lower front and rear frame (28 ) and the cutting blade frame (29) constitute a fixed frame (24), and the lower part of the pulling case (31) of the pulling device (9) It is attached to the fixed state to a separatory grass rod (30) of the partial grass device (8), the rear is connected by movable lateral frame in the lateral direction (36) of each partial grass rods (30), each pull force device A vertical transmission cylinder (37) is provided at the upper part of the pulling case (31) of (9), and the upper part of each transmission cylinder (37) is fixedly attached to the upper transmission case (38) in the left-right direction. rod (30) and the upper transmission case (38) causes connecting the two Over scan (31) and the moving-side lateral frame (36) for connecting the respective partial grass rods (30) and a have constituted a movable frame (25), said cutting vertical support frame frame (18) (20) the fixed frame provided on the side (24) divided form to the mobile frame (25) to move relative to the stationary frame (24), said moving frame (25) at least partial grass apparatus side (8) and causing device (9) is provided constitutes a cause units (26), said moving frame (25) is provided in the upper any fixed part of the fixed frame as a shaft center of the upper transmission case (38) (24) pivoting about the (S) by the upper pivoted around, as well as opening the front side of the minute grasses device (8) and causing device (9) is rotated upward in the vehicle body traveling direction cutting blade (10) , the center of gravity of the movable frame (25) (G) is the pivot Is configured to be located above the rear side than the heart (S), the mounting portion or its vicinity of the upper transmission case (38) and left and right side frame over arm (27), detecting the position of said moving frame (25) the cause unit position detecting means (40) provided, the cited electromotive unit position detecting means (40), the front Symbol provided an upper transmission case rotator disc shaped (38) (41), the rotating body (41) the switch (42) to either one of the fixed portions of the left and right side portions the frame (27) is provided, to the switch to any other fixed part of the left and right side frames rotating body (41) (27) (42) This contacting a plurality of the abutting member (43) and structure provided with, wherein the cause unit (26), the cited electromotive unit (26) ultrasonic sensors type obstacle detection means for detecting the position of the obstacle in front of the a plurality (44) up and down, the disorder When caused units by the detection means (44) (26) is detected to have approached the predetermined distance obstacle, Combine, characterized in that the arrangement for automatically upwardly pivoted causes unit (26).

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