JPH06225604A - Cover device for rotary - Google Patents

Abstract

PURPOSE:To level the whole surface of a field by preventing the track of a chain case on the field during deep tilling by a side drive type rotary with a backward and forward rotatable rotary cover not enlarging an interval between both right and left sides of a rear cover and a rear edge of right and left side covers. CONSTITUTION:A back plate 71 of a rear cover 67 which covers the rear of a rotary tilling part laid at a lower part between a chain case 21 and a side frame 22 and has the back plate for leveling a tilled field is extended to the rear of the chain case 21. The rear parts of right and left side covers 68L and 68R which are equipped with side plates 72 at both right and left sides of the back plates 71, cover both right and left sides of the rotary tilling part and are held on the chain case 21 and the side frame 22 rotatably around the center of a pawl shaft are arranged closely to the inside of the left and right direction of the side plate 72 in such a way that the rear parts of the right and left covers are lapped over the side plates 72 in a side view.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cover device.

[0002]

2. Description of the Related Art There is a side drive type rotary, and in this type, a rotary case is provided between a lower part of a chain case provided on one side of a rotary machine frame and a side frame provided on the other side thereof. The pawl shaft is rotatably supported, and a large number of plowing pawls are provided on the pawl shaft to form a rotary plowing part.
A rotary cover is provided to cover the rotary tillage part.

The rotary cover is pivotally connected to a main cover for covering the upper part of the rotary tillage part and a rear end portion of the main cover so as to be swingable about a left and right axis so as to cover the rear part of the rotary tillage part and to cultivate it. The rear cover having a back plate for arranging the farm field, and the left and right side covers fixed to the left and right sides of the main cover and covering the left and right sides of the rotary tillage section are provided.

The left and right side covers are supported by the chain case and the side frame so as to be rotatable about the claw shaft axis, and the rotary cover is freely rotatable around the claw shaft center according to the working depth. There was something that was done.

[0005]

In the above-mentioned conventional apparatus, when the field is deeply cultivated, the rotary frame is lowered to lower the position of the rotary tiller and the rotary cover is rotated forward. In this case, after plowing, the chain case marks (grooves) remain in the field, and the left and right sides of the rear cover and the rear edges of the left and right side covers are wide open, resulting in a uniform distribution over the entire field. There is a problem that it is difficult to level the ground.

Therefore, the present invention prevents the traces of the chain case from remaining during deep plowing, and takes into consideration that the space between the left and right sides of the rear cover and the rear end edges of the left and right side covers is not greatly opened. , The purpose is to achieve leveling over the entire field.

[0007]

The technical means taken by the present invention to achieve the above-mentioned object is to provide a lower portion between a chain case 21 provided on one left and right side and a side frame 22 provided on the other side. The rotary shaft 27 is rotatably supported, and a large number of plowing pawls 26 are provided on the pawl shaft 25 to form a rotary plowing part 27. A main cover 66 that covers the rotary plowing part 27 from above is provided. The rotary tiller 2 is pivotally connected to the rear end of the cover 66 so as to be swingable about the left and right axes.
Back plate 7 that covers the rear of 7 and level the cultivated field
1, which is fixed to the left and right side portions of the rear cover 67 and the main cover 66, covers the left and right sides of the rotary tiller 27, and allows the chain case 21 and the side frame 22 to rotate about the claw shaft 25 axis. In the rotary equipped with the supported left and right side covers 68L, 68R, the rear plate 71 of the rear cover 67 is extended rearward of the chain case 21, and the side plates 7 are provided on both left and right sides of the rear plate 71.
2, and the rear portions of the side covers 68L, 68R are disposed inwardly of the side plate 72 in the left-right direction so as to wrap around the side plate 72 in a side view.

[0008]

When the field is deeply cultivated, the rotary is lowered to lower the position of the rotary tillage and the side cover is rotated forward together with the main cover and the rear cover around the claw shaft axis. At this time, since the rear plate of the rear cover is extended to the rear of the chain case, the rear plate evenly grounds the rear of the chain case, and the rear part of the side cover has the rear plate on both left and right sides. The inner side of the side plate of the rear cover is closely arranged so as to overlap with the side plate in a side view, so that a large gap is formed between the left and right sides of the rear cover and the rear end edges of the left and right side covers. The field is leveled evenly over the entire surface without being lost.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 3, a rotary 3 as a working machine is mounted on a rear portion of the tractor 1 via a mounting device 2. The mounting device 2 mainly includes a three-point link 6 including a top link 4 and a pair of left and right lower links 5, and a connecting frame 7 connected to the rotary 3. The front end side of the top link 4 is a mounting base 8 fixed to the rear end surface of the tractor 1.
The front end sides of the left and right lower links 5 are pivotally connected to the left and right side portions of the rear portion of the tractor 1. Further, the front and rear midway portions of the left and right lower links 5 are connected via a lift rod 9 to a lift arm 11 of a working machine lifting hydraulic device 10 provided on the rear part of the tractor 1.

As shown in FIGS. 4 and 5, the connecting frame 7 is composed of a main frame 12 having a mountain shape in front view, and a reinforcing frame 13 for connecting the lower left and right side portions of the main frame 12 to each other. A pair of left and right hook plates 1 on the top
4, the upper hitch pin 15 is provided between the left and right hook plates 14, and the rear end side of the top link 4 is pivotally connected between the hook plates 14 of the upper hitch pin 15. Further, the rear ends of the lower links 5 are pivotally connected to the left and right lower ends of the main frame 12. The connecting frame 7 is provided with a connecting body to which the rear end side of the universal joint 17 whose front end side is connected to the PTO shaft 16 of the tractor is connected.

The rotary 3 has the structure shown in FIGS. 1, 2, 3 and 6.
As shown in FIG. 3, the rotary machine frame 18 has a cylindrical support arm 20 protruding left and right from a central gear case 19, and the right support arm 20
A chain case 21 on the left support arm 20
The side frames 22 are attached and fixed to the rear side and are formed in a rear view gate shape. A top mast 23 is provided so as to project upward from the left and right sides of the gear case 19, and a hook plate 14 of the connecting frame 7 is engaged from below with a pin 24 provided on the upper end side of the top mast 23. The left and right lower ends of the main frame 12 are detachably connected to the left and right support arms 20.

To mount the rotary 3 on the tractor 1, the tractor 1 is moved backward to the rotary 3 placed on the ground, and the hook plate 14 of the mounting device 2 is placed below the pin 24 of the top mast 23. Position the lift arm 1
1 is rotated upward to move the connecting frame 7 upward. Then, the rotary 3 is lifted and rotated forward around the pin 24, the left and right support arms 20 are connected to the lower left and right sides of the main frame 12 of the mounting device 2, and the universal joint 17 is interlockingly connected to the input shaft 29. It is supposed to be done.

Chain case 21 and side frame 22
A pawl shaft 25 is rotatably installed between the lower parts of the and, and a large number of plowing pawls 26 are fixed on the pawl shaft 25. The pawl shaft 25 and the plowing pawl 26 serve as a rotary working unit as a rotary working unit. 27 are configured. The rotary machine frame 18 also supports a rotary cover 28 that covers the upper, rear, and left and right sides of the rotary tiller 27.

As shown in FIGS. 4 and 7 (bottom view), the inside of the gear case 19 is in communication with the inside of the left and right support arms 20, and an input shaft 29 is arranged on the front side of the gear case 19 and the input is carried out. The shaft 29 is rotatably supported by a bearing case 30 mounted on the gear case 19 via bearings, and is also interlocked with the rear end side of the universal joint 17. A bevel pinion 31 is integrally formed on the rear portion of the input shaft 29.
A bevel gear 32 is engaged with the bevel gear 32.
As shown in FIG. 8, is attached to the left side of the transmission shaft 33 arranged in the center of the gear case 19 in the left-right direction via a bush so as to be relatively rotatable, and communicates with the left support arm 20 of the gear case 19. It is rotatably supported by a lid 34 that closes the end opening of the opening.

A shaft coupling 35 is provided on the right outer periphery of the transmission shaft 33.
The shaft joint 35 is spline-fitted and fixed by a spring pin 36, and the shaft coupling 35 is supported on the inner surface side of the gear case 19 via a bearing. The intermediate shaft 37 arranged at is spline-fitted. The intermediate shaft 37 is linked to the pawl shaft 25 via a chain transmission mechanism in the chain case 21.

Further, between the shaft coupling 35 and the bevel gear 32, a shifter 38 is fitted on the transmission shaft 33 so as to be slidable in the axial direction, an engaging tooth 39 provided on the shifter 38, and a bevel gear. A clutch 41, which is provided in 32 and includes an occlusal tooth 40 that is engaged with the occlusal tooth 39 so as to engage and disengage freely, is provided. The power between the bevel gear 32 and the transmission shaft 33 is interrupted via the clutch 41, and the power from the PTO shaft 16 is input to the input shaft 29, the bevel pinion 31, the bevel gear 32, the transmission shaft 33, and the shaft coupling 3.
5, transmitted to the claw shaft 25 via the transmission device including the intermediate shaft 37 and the chain transmission mechanism in the chain case 21,
The cultivating part 27 is rotationally driven.

A rear surface of the gear case 19 is opened and a power take-out gear unit for driving the car wash pump is attached. If the gear unit is not attached, the rear opening is closed by a lid. It is supposed to be done. The shifter 38 is urged toward the bevel gear 32 side by a coil spring 43 which is interposed between the shifter 38 and the bearing 42 in a compressed state. A pair of pins 45 of the shift fork 44 are engaged with the circumferential groove 38a of the shifter 38 via rollers. The shift fork 44 has a boss portion 4 on the inner end side of a fork shaft 46 which is inserted and supported on the front side of the gear case 19 above the input shaft 29.
7, fixed via bolts 48.

As shown in FIGS. 4 and 5, the right end of the first link 49 is fixed to the outer end of the fork shaft 46.
The rear end side of the second link 50 is in contact with the lower end side lower surface of the first link 49. A cylinder shaft 51 is fixed to a middle portion of the second link 50 in the front-rear direction, and the cylinder shaft 51 is provided between left and right side walls of a bracket 52, which is fixed to the reinforcing frame 13 of the connecting frame 7 and has a downward U-shape in a front view. It is externally fitted to the support pin 53 so as to be rotatable about the left and right axes. In addition, the cylinder shaft 51
A torsion coil spring 54 is externally fitted to the one end of the second frame 50. One end of the torsion coil spring 54 is in contact with the lower surface of the front portion of the second link 50 and the other end is in contact with the lower surface of the reinforcing frame 13.
The rear end side of the second link 50 is urged downward around the support pin 53, and the upper surface of the front part of the second link 50 is attached to the bracket 5.
The rotation of the second link 50 due to the urging is restricted by coming into contact with the upper wall.

A lower end of a tubular body 55 is pivotally connected to a front portion of the second link 50 via a pin 56, and a lower portion of a rod 57 is inserted into the tubular body 55 so as to be relatively movable in the axial direction. . A plurality of holes are formed in the upper part of the rod 57 at intervals in the axial direction, and the positioning pin 5 is formed in these holes.
8 is selectively inserted, and the positioning pin 58 and the cylindrical body 5 are inserted.
A coil spring 59 is interposed between the upper end surface 5 and the upper end surface 5 in a compressed state.

The upper end of the rod 57 has a third link 60.
Is connected to the front lower part of the third link 60 through a pin 61, and a cylindrical shaft 62 is fixed to the upper rear end side of the third link 60 so as to be externally fitted to the upper hitch pin 15 so as to be rotatable about the left and right axes.
Further, the third link 60 has a front part bent obliquely downward and a lower end side bent rightward, and the bent part 63 is located below the top link 4. It is supposed to face each other.

Further, the lower surface of the rear end of the third link 60 is in contact with the stopper pin 64 provided on the hook plate 14 so that the upward rotation around the upper hitch pin 15 is restricted. Then, the shift fork 44, the fork shaft 46, the first link 49, the second link 50, the tubular body 55, the rod 57, the third link 60, and the like interlock a mechanism that engages and disengages the clutch 41 in conjunction with the elevation of the rotary 3. It constitutes 65.

Then, for example, when the tractor 1 is turned on the ridge at the time of tilling, the rotary 3 is lifted to move the rotary tiller 27 from the working position shown in FIG. 3 to the non-working position (the tiller 27 is removed from the field). Although the top link 4 is rotated to the position shown by the phantom line in FIG. 4, the bent portion 63 of the third link 60 approaches the top link 4 and abuts against it. 4, the third link 60 pivots backward around the upper hitch pin 15 to push down the rod 57.

As a result, the coil spring 59 is compressed, and when the spring force of the coil spring 59 overcomes the spring force of the torsion coil spring 54, the front portion of the second link 50 is pushed down via the tubular body 55, and the second link 50 is pushed down. The rear part pivots upward around the support pin 53 and the left end side of the first link 49 is pulled up. When the first link 49 is pulled up, the fork shaft 46 is rotated, and the shifter 38 engages the occlusal teeth 39 and the occlusal teeth 40 via the shift fork 44 (the right side of FIG. 7 and FIG. 8). (Shown on the lower side of FIG. 7) to the non-released state (shown on the left side of FIG. 7 and the upper side of FIG. 8) against the spring force of the coil spring 43, and the power from the PTO shaft 16 to the pawl shaft 25 is cut off. The rotation of the tiller 27 is stopped.

Next, when the plowing part 27 is lowered to the working position from the above-mentioned state, the interlocking mechanism 65 is returned to the original state by the reverse operation due to the spring force of the coil springs 43 and 59 and the torsion coil spring 54. The clutch 41 is connected. As shown in FIGS. 1, 2, 6, and 9 to 13, the rotary cover 28 covers the upper part of the cultivating part 27 and the rear part of the cultivating part 27 and evens the cultivated field. It is composed of a rear cover 67 that is leveled flat and side covers 68R and 68L that cover the left and right sides of the tilling part 27.

The main cover 66 is mainly composed of an upper plate 69 and left and right side plates 70 fixed to both left and right sides of the upper plate 69. The rear cover 67 is mainly composed of a back plate 71 and left and right side plates 72 whose back sides are fixed to left and right side parts of the back plate 71, and a front upper end portion of the back plate 71 is a left and right side part of the main cover 66. The plate 70 is fixed to a cylinder shaft 73 formed between the rear end portions of the plate 70 and pivotally connected to the left and right side plates 70, and the rear cover 67 is attached to the main cover 66 so as to be rotatable about the left and right axes. ing. The right side of the back plate 71 of the rear cover 67 is extended to the right of the cultivating part 27 to cover the rear of the chain case 21,
Even the back of the chain case 21 can be leveled evenly.

The left and right side covers 68L, 68R are composed of main side plates 74L, 74R and rear side plates 75L, 75R arranged behind the main side plates 74L, 74R. The main cover 6 is provided on the upper ends of the main side plates 74L and 74R.
The lower end side of the side plate 70 of 6 is bolted, and the main side plate 7
The lower ends of the 4L and 74R are supported by the lower portions of the chain case 21 and the side frame 22 so as to be rotatable back and forth around the claw shaft 25 axis. The rotary cover 28 can be rotated back and forth and stopped by a screw type expansion / contraction adjusting mechanism 89 provided between the top mast 23 and the main cover 66, and the pawl shaft of the rotary cover 28 can be adjusted in correspondence with the working depth. Two
The position is adjusted about 5 times (when the plowing depth is deep, the rotary cover 28 is rotated forward, and when the plowing depth is shallow, the rotary cover 28 is rotated backward).

Main side plate 74L of the left side cover 68L
The lower support structure of is as shown in FIG. That is, the drive shaft 76 is attached and fixed to the end portion of the pawl shaft 25, and the drive shaft 76 is supported by the bearing 78 that is fitted and supported in the cylindrical bearing holder 77 that penetrates the inner wall of the chain case 21. A lower sprocket 79 of a chain transmission mechanism is spline-fitted to the drive shaft 76. A flange 80 is provided on the inner end of the bearing holder 77, and the flange 80 is sandwiched and fixed by the outer surface of the inner wall of the chain case 21 and a protective cover 81 which is fixed to the inner wall of the chain case 21 by bolts and nuts. There is. A circumferential groove 82 that is open outward is formed on the outer end side of the protective cover 81 in the left-right direction, and a circular mounting hole 83 is formed under the main side plate 74L of the left side cover 68L. The mounting hole 83 is fitted into the circumferential groove 82 together with the liner 84, and the main side plate 74L is sandwiched between the outer surface of the inner wall of the chain case 21 and the protective cover 81.

Further, as shown in FIG. 11, a mounting hole 85 is also formed in the main side plate 74R of the right side cover 68R, and this mounting hole 85 supports the support shaft 86 at the end of the pawl shaft 25. The right side cover 68R is rotatably fitted to the outer circumference of the bearing case 88 into which the bearing 87 is fitted.
The bearing 87 is fixed to the lower portion of the side frame 22.

Rear side plate 75L of the left side cover 68L
As shown in detail in FIGS. 9 and 10, the front upper part is fixed to the lower rear end of the side plate 69 of the main cover 66, and the middle and lower parts of the front part are the rear edges of the main side plate 74L. Bolt on the side
It is attached and fixed by nuts. Further, the front and rear midway portions of the rear side plate 75L are bent rearward in a laterally outwardly inclined shape, and the rear part is lapped in proximity to the inner surface side of the left side plate 72 of the rear cover 67 in a side view. It is arranged.

Rear side plate 75R of the right side cover 68R
Has a flat plate shape, is fixed to the side plate 69 and the main side plate 74R of the main cover 66 in the same manner as described above, and is closely arranged by being wrapped around the inner surface of the right side plate 72 of the rear cover 67. There is. Therefore, even if the rotary cover 28 is rotated forward, the main side plate 74 of the side covers 68L and 68R is rotated.
The rear edge of the L, 74R and the front edge of the side plate 72 of the rear cover 67 are prevented from opening.

As shown in FIGS. 11, 12 and 13,
On the right side of the rotary cover 28, there is a guard rail 90 for contacting the pillar during the plowing work in the greenhouse.
Are arranged in the front-back direction. A pair of front and rear L-shaped metal fittings 91 are fixed to the guard rail 90, and these L-shaped metal fittings 91 are fixedly attached to the rotary cover 28 so that the rotary cover 28 can be pivoted back and forth even if the working depth is changed. Therefore, it always keeps the same posture.

As shown in FIGS. 6 and 15, an elastic cover 92 is provided on the inner surface side of the rotary cover 28 for the purpose of preventing soil adhesion. The elastic cover 92 is a front cover 92 provided on the inner surface of the upper plate 69 of the main cover 66.
a and a rear cover 92b provided on the inner surface of the rear plate 71 of the rear cover 67. Further, the rotary 3 is provided with an automatic plowing depth adjusting function so as to keep the plowing depth set at a constant level. As shown in FIGS. 1, 2, 15 and 16, the rotary portion 3 is provided with a rear portion. A method of using the cover 67 and the wire 93 is adopted. The wire 93 is composed of an inner wire 94 and an outer wire 95. One end of the inner wire 94 is pivotally connected to a bracket 96 fixed to the right upper rear surface of the rear cover 67, and the other end is pivotally movable back and forth on the right support arm 20. It is pivotally connected to a supported arm 97 and is urged forward by a spring 98. The arm 97 is linked to a control valve of the hydraulic device 10 by an interlocking mechanism. Further, one end of the outer wire 95 is attached to a fixed bracket 99 on the right side of the upper surface of the main cover 66, and the other end is attached to a fixed bracket 100 in the middle of the right support arm 20. The bending between 100 is adapted to correspond to the longitudinal rotation adjustment of the rotary cover 28.

As shown in FIG. 2, on the rear side of the rotary cover 28, a pair of right and left lowering devices 101 that straddle a main cover 66 and a rear cover 67 are provided. The coil spring 1 fitted on the lowering rod 102 of the lowering device 101.
Due to the spring force of 03, the rear cover 67 is lowered downward at the time of plowing. The lower end side of the down rod 102 is pivotally attached to the rear cover 67, and the upper side is axially slidably inserted into the block body 104 as shown in FIG. The bracket 105 is pivotally attached to the protruding bracket 105. The down rod 102 is made of a pipe material, and a plurality of circular holes 106 are formed in the axial direction on the upper side, and the block body 104 has a circular lock pin 107 having a circular cross section and the lock pin 107 is pushed down. A spring 108 for urging the rod 102 side is incorporated, and as shown in FIG. 18, the rear cover 67 is lifted and the lock pin 107 is selectively inserted into the circular hole 106, thereby exchanging the tillage claw 26. In such a case, the rear cover 67 can be held in a lifted state around the cylinder shaft 73.

The lock pin 107 has an operating lever 1
09 is provided and the lock pin 107 can be detached from the circular hole 106 and held in the detached state by the turning operation of the operation lever 109. 19 and 20.
In the figure, 110 is a tightener for applying tension to the chain 111 of the chain transmission mechanism provided in the chain case 21. The upper end of the tightener 110 is pivotally attached to the upper portion of the U-shaped bracket 112 via a pin 113, and the bracket 112 is fixed to the inner surface of the lid plate 115 that closes the tightener mounting hole 114 provided in the chain case 21. Further, an upper portion of a damper 116 that backs up the tightener 110 when the tightener 110 is pressed by the chain 111 and bent, is pivotally attached to a lower portion of the bracket 112 via a pin 117. This Tightna 11
0 is made of an elastic material, and the lower part is in contact with the inner surface of the chain case 21.

[0035]

According to the present invention, the rear plate of the rear cover having the rear plate for covering the rear of the rotary tilling portion provided between the lower portion of the chain case and the side frame and arranging the cultivated field is chained to the rear plate. Along with extending to the rear of the case, side plates are provided on both the left and right sides of the back plate to cover the left and right sides of the rotary tillage part, and the left and right sides supported by the chain case and side frame to be rotatable around the claw shaft axis. By arranging the rear part of the side cover on the inner side in the left-right direction of the side plate so as to overlap with the side plate in a side view, when rearing the field, the rear plate evens the rear of the chain case. The ground can be leveled evenly, and the field can be leveled evenly over the entire surface without wide opening between the left and right sides of the rear cover and the rear end edges of the left and right side covers.

[Brief description of drawings]

FIG. 1 is a rear view of a rotary.

FIG. 2 is a side view of a rotary.

FIG. 3 is an overall side view.

FIG. 4 is a side sectional view of a connecting portion of a rotary.

FIG. 5 is a partial front sectional view of a connecting portion of a rotary.

FIG. 6 is a side sectional view of a rotary.

FIG. 7 is a bottom cross-sectional view of the gear case.

FIG. 8 is a rear cross-sectional view of the gear case.

9 is a cross-sectional view taken along the line AA of FIG.

10 is a cross-sectional view taken along the line BB of FIG.

FIG. 11 is a right side view of the rotary cover.

FIG. 12 is a plan view of the right side of the rotary cover.

13 is a cross-sectional view taken along the line CC of FIG.

FIG. 14 is a cross-sectional view showing a lower support structure of the right side cover.

FIG. 15 is a side sectional view of a rear end side of a main cover of a rotary cover.

FIG. 16 is a side sectional view showing a front attachment structure of the working depth detecting wire.

FIG. 17 is a side sectional view showing an upper structure of the lowering device.

FIG. 18 is an explanatory diagram showing a state in which the lock pin is inserted into the circular hole of the lowering rod.

FIG. 19 is a side sectional view showing a tightener mounting structure.

FIG. 20 is a vertical cross-sectional view of a tightener mounting structure.

[Explanation of symbols]

 21 Chain Case 22 Side Frame 25 Claw Shaft 26 Tilling Claw 27 Rotary Tilling Section 66 Main Cover 67 Rear Cover 68L Side Cover 68R Side Cover 71 Rear Plate 72 Side Plate

Front page continuation (72) Inventor Mitsuyoshi Hirata 64 Ishizukita-machi, Sakai City, Osaka Prefecture Kubota Sakai Factory Co., Ltd. (72) Inventor Takashi Sugawara 64, Ishizukita-machi, Sakai City Osaka Prefecture Kubota Sakai Factory Co., Ltd.

Claims (1)

[Claims] 1. A chain case (2) provided on the left and right sides.
A claw shaft (25) is rotatably supported between the lower part of 1) and the side frame (22) provided on the other side, and a large number of tilling claws (26) are provided on the claw shaft (25). The rotary tillage part (27) is constituted, and this rotary tillage part (27)
A main cover (66) for covering the upper part of the
6) A rear cover (67) having a rear plate (71) pivotally connected to the rear end of the rotary tilling section (27) so as to be swingable about the left and right axes and covering the rear of the rotary tilling section (27) and arranging the cultivated field. And fixed to the left and right sides of the main cover (66) to cover the left and right sides of the rotary tillage part (27) and to rotate the claw shaft (25) around the chain case (21) and side frame (22). In a rotary equipped with left and right side covers (68L) and (68R) rotatably supported, a rear plate (71) of the rear cover (67) is extended rearward of a chain case (21). , This back plate (7
1) The side plates (72) are provided on both the left and right sides, and the rear portions of the side covers (68L) and (68R) are located inside the left and right sides of the side plates (72) in a side view with the side plates (72). A rotary cover device, which is arranged in close proximity so as to be wrapped with.