JP2008211998A - Rotary power tiller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the force of lifting a rear cover by a rod member of a cover bouncing-down device for urging the rear cover of a rotary power tiller in the grounding direction, and to facilitate the recognition of the amount of expansion/contraction of the rod member when tilling is carried out in such a state that the rear cover is slightly lifted from a ground surface. <P>SOLUTION: In this rotary power tiller, a lift is screwed into a screw shaft so that the lift can be moved in the longitudinal direction of a supporting rod by the rotation of the screw shaft around the axial center. The one side of a machine frame and the rear cover is connected to a holder so that the rear cover can be lifted or lowered by movement of the holder in the longitudinal direction of the supporting rod. In order to fluctuate a position to regulate the movement of the rear cover in the grounding direction, depending on the position of the movement of the lift in the longitudinal direction of the supporting rod, the movement of the holder to the other side of the machine frame or the rear cover is regulated by the lift. A spring for pressing the holder toward the other side of the machine frame or the rear cover is installed so as to urge the rear cover in the grounding direction. An assist spring for urging the lift to the one side of the machine frame or the rear cover is installed so as to assist the movement of the lift in the direction of lifting the rear cover. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary cultivator.

Conventionally, to cultivate a farm field, there is a rotary cultivator that is detachably mounted on a rear part of a tractor via a three-point link mechanism or the like and cultivated while moving the farm field (see Patent Document 1).
The rotary tiller includes a machine frame connected to a three-point link mechanism, a rotary tiller provided at a lower portion of the machine frame, and a rotary cover that covers the rotary tiller.
The rotary cover includes an upper cover that covers the top of the rotary tiller and a rear cover that covers the rear of the rotary tiller. The upper cover is fixed to the machine frame side, and the front cover has a front end that is the upper cover. An inclination that is supported so as to be pivotable around the left and right axis via a support shaft disposed in the left and right direction on the rear end side, and that can swing up and down, and that moves downward as it moves backward. The rear end side touches the field and levels the field.

In the rotary tiller, a pair of left and right cover lowering devices that urge the rear cover in the grounding direction are provided across the machine frame and the rear surface of the rear cover.
This cover lowering device includes a rod member that is not extendable in the length direction, a coil spring that is fitted to the rod member, and a holder through which the rod member is inserted and that is relatively movable in the axial direction with respect to the rod member. And a spring receiving member for positioning the end of the coil spring.
The front end side of the rod member is pivotally connected to a front mounting portion fixed on the machine frame side so as to be rotatable about the left and right axis, and the holder is rotated about the left and right axis to a rear mounting portion provided on the back side of the rear cover. The coil spring is disposed between the holder and the front mounting portion, and the spring receiving member is disposed between the coil spring and the front mounting portion.

On the rear end side of the rod member, a retaining portion is provided to prevent the rod member from coming out of the holder to the front side, and the spring receiving member is detachably engaged with an engagement groove provided on the rod member. And a key member for restricting movement of the spring receiving member in the rod axial direction (rod length direction).
A plurality of engaging grooves with which the key member of the spring receiving member engages are formed at intervals in the axial direction of the rod member. The key receiving member is separated from the engaging groove and the spring receiving member is moved in the axial direction of the rod member. By sliding the key member into another engagement groove, the position of the spring receiving member can be changed in the axial direction with respect to the rod member.

In the cover lowering device having the above configuration, the rear end side of the rear cover is grounded and the coil spring is compressed between the spring receiving member and the holder during tilling, and the rear cover swings up and down. It is possible and is biased in the grounding direction by the biasing force of the coil spring.
In the cover lowering device, the holder is provided with a lock pin, and the lock pin engages with a lock hole formed in the rod member to thereby move the holder in the axial direction of the rod axis of the holder. The relative movement is restricted and the downward swing of the rear cover is restricted.

The lock pin can be held in an unlock position where the lock pin is removed from the lock hole, and by holding the lock pin in the lock release position, relative movement of the holder relative to the rod member in the axial direction of the rod member is allowed. .
Further, the holder is provided with a spring member that urges the lock pin in a direction to engage the lock hole when the lock pin is brought into an engageable state with the lock hole.
In the rotary cultivator described above, at the time of tilling, the lock pin is held at the unlocking position so as to allow relative movement of the holder in the axial direction of the rod member with respect to the rod member.

Also, when performing maintenance or the like on the rotary tiller or the rotary cover, the key member of the spring receiving member is positioned so as to be disengaged from the engaging groove so that the spring receiving member can slide in the axial direction of the rod member. When the rear cover is lifted and swung upward with the lock pin engageable with the lock hole, the lock pin is automatically engaged with the lock hole by the biasing force of the spring member, and the rear cover is moved to the ground. It is configured so that it can be locked at a position that is greatly elevated.
Further, during the work, the rear cover may be held in a state where the grounding portion of the rear cover is slightly lifted from the ground by the lock pin, and the tilling work may be performed in this state.
JP 2005-143390 A

In the conventional rotary cultivator, when performing maintenance on the rotary cultivator or the rotary cover, the rear cover must be lifted up considerably, but if mud is attached to the front side of the rear cover, Lifting the rear cover requires a significant lifting force, which is hard work and may not be lifted by one worker depending on the amount of mud.
Also, when plowing work with the rear cover slightly lifted from the ground, the rear cover rises due to the rising of the soil, the lock pin engages with the front lock hole, and the rear cover is locked at the raised position. It may be said that.

In addition, the vertical position adjustment of the rear cover is a stepped adjustment, and there is a problem that fine adjustment cannot be performed.
In view of the above problems, the present invention is intended to reduce labor when lifting the rear cover and to adjust the vertical position of the rear cover steplessly and accurately.

The technical means of the present invention for solving this technical problem is provided in the machine frame with a rotary cultivating part for cultivating a field and an upper cover covering the upper part of the rotary cultivating part, on the rear end side of the upper cover. A rotary tiller provided with a cover lowering device that includes a rear cover that is pivotally connected to be pivotable about a horizontal axis, and that urges the rear cover in the grounding direction across the rear cover side and the machine frame side. In the machine
The cover lowering device is provided with a support rod projecting from one side of the machine frame or the rear cover toward the other, and is disposed along the longitudinal direction of the support rod, and is restricted in movement in the longitudinal direction of the support rod and around the axis. A screw shaft that is rotatably supported, a lift that is movable in the longitudinal direction of the support rod and non-rotatably supported on the other side of the machine frame or the rear cover of the support rod, and is movable in the longitudinal direction of the support rod. And a holder held in the
The holder is screwed into the screw shaft so that the lift moves in the longitudinal direction of the support rod by rotation around the axis of the screw shaft, and the rear cover moves up and down by movement of the holder in the longitudinal direction of the support rod. The other side of the machine frame or the rear cover is connected to the support frame, and the lift restricts the position of the machine frame or the rear cover of the holder by the lift so that the movement restriction position of the rear cover in the grounding direction varies depending on the movement position of the lift support rod in the longitudinal direction. A spring is provided to press the holder toward the other side of the machine frame or the rear cover so that the rear cover is biased in the grounding direction, and the lift lifts the rear cover. An assist spring for urging the lift to one side of the machine frame or the rear cover is provided to assist the movement in the direction of movement.

According to another technical means of the present invention, the holder is held on one side of the machine frame or the rear cover rather than the lift of the support rod, and the holder is pressed against the lift by the bias of the spring. Thus, the lift restricts the movement of the holder to the other side of the machine frame or the rear cover so that the movement restriction position of the rear cover in the grounding direction varies according to the movement position of the lift in the longitudinal direction of the support rod. It is in the point which is comprised.
According to another technical means of the present invention, a front mounting portion is provided on the machine frame side, a rear mounting portion is provided on the rear cover side, the support rod is formed in a cylindrical shape, and the periphery of the support rod is provided. An opening window that opens partly in the direction is formed in the longitudinal direction of the support rod, and the front or rear end of the support rod can swing around the rotation axis in the left-right direction at one of the front mounting portion or the rear mounting portion. The screw shaft is inserted and held in a support rod so as to be rotatable about its axis, and the lift includes an internal fitting portion fitted into the support rod, an external fitting portion fitted into the support rod, and an internal fit. And a connecting portion for connecting the outer fitting portion and the outer fitting portion through an opening window of the supporting rod, and the lift is moved in the longitudinal direction of the supporting rod by fitting the inner fitting portion and the outer fitting portion of the lift to the supporting rod. The lift is held movably, and the lift is held non-rotatable around the shaft center by the fitting of the connecting portion to the opening window of the support rod. There is provided screwed screw hole, the holder is that is freely fitted moved in the longitudinal direction of the support rod.

According to another technical means of the present invention, a spring receiving member is fitted and held on one side of the machine frame or the rear cover of the support rod so as to be movable and adjustable in the longitudinal direction of the support rod. The other side of the machine frame or the rear cover is externally fitted so as to be movable in the longitudinal direction of the support rod, and the spring is constituted by a coil spring, and is fitted between the spring receiving member of the support rod and the holder in a compressed state. It is in a held point.
According to another technical means of the present invention, the assist spring is constituted by a tension coil spring and is fitted in a support rod in a state of being externally fitted to the screw shaft, and the lift is attached to one of the machine frame and the rear cover. It is in the point comprised so that it may pull toward the side.

According to the rotary cultivator of the present invention, when maintaining the rotary cultivator and the like, the rear cover can be greatly lifted by rotating the screw shaft around the axis to move the lift in the longitudinal direction of the support rod. Thus, it is not necessary to lift the rear cover directly by hand, and the work labor can be reduced.
In addition, when plowing with the grounding part of the rear cover slightly lifted from the ground during plowing, the rear cover is swung upward by moving the lift in the opposite direction to the above. The grounding part can be securely held in a state of being slightly lifted from the ground, and the vertical position adjustment of the rear cover can be adjusted steplessly, and the lower limit position of the rear cover can be set with high accuracy.

  In addition, an assist spring is provided to urge the lift to one side of the machine frame or the rear cover to assist the lift in moving in the direction of raising the rear cover. When the lift is moved in the direction that raises the rear cover with respect to the support rod, mud adheres to the back surface of the rear cover or mud accumulates on the upper surface of the rear cover, increasing the weight of the entire rear cover. However, the rear cover can be lifted smoothly by rotating the screw shaft with a light force.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 2, reference numeral 1 denotes a rotary cultivator that is attached to a rear portion of a vehicle such as a tractor so as to be detachable and movable up and down via a three-point link mechanism or the like and cultivates while moving in a field.
The rotary tiller 1 includes a machine frame 2 connected to a three-point link mechanism, a rotary tiller 3 provided at a lower portion of the machine frame 2, and a rotary cover 4 that covers the rotary tiller 3. Yes.
As shown in FIGS. 2 and 3, the machine frame 2 has support arms 6 projecting from the left and right sides of the gear case 5 at the center in the left-right direction, and a plate material on the outer end side of the left and right support arms 6. The side frames 7L and 7R, which are arranged so that the plate thickness direction coincides with the left-right direction, are provided in a downward projecting shape, and the power is transmitted to the rotary tiller 3 on the left-right outer surface of the left side frame 7L. The transmission case 8 which accommodates is attached.

The rotary tiller 3 includes a claw shaft 9 that is rotatably supported about the left and right axial centers between the lower portions of the left and right side frames 7L and 7R, and a plurality of tilling claws attached to the claw shaft 9 in the left and right directions. 10.
The gear case 5 of the machine frame 2 is provided with an input shaft for inputting power from the PTO shaft of the tractor to the transmission mechanism in the gear case 5 through a universal joint or the like. The power input through this input shaft is It is transmitted from the transmission mechanism in the gear case 5 to the transmission mechanism in the transmission case 8 via the transmission shaft in the left support arm 6, and is transmitted from the transmission mechanism in the transmission case 8 to the claw shaft 9, The claw shaft 9 is configured to be rotationally driven in the direction of arrow A around the axis.

The rotary cover 4 includes an upper cover 11 that covers the top of the rotary tiller 3, a rear cover 12 that covers the rear of the rotary tiller 3, and a pair of left and right side covers 13 that covers both the left and right sides of the rotary tiller 3. And comprising.
The upper cover 11 has an end portion in the left-right direction fixed to a side plate 14 fixed inside the left and right side frames 7L and 7R.
When plowing, the rear cover 12 is disposed in an inclined shape that moves downward as it goes rearward, and its upper end side (front end side) is the rear end side between the left and right side plates 14 (rear end side of the upper cover 11). The rear cover 12 is supported from the rotary tiller 3 to the rear by being pivotally supported by a pivot 16 disposed in the left-right direction. While receiving the cultivated soil, the lower end side (rear end side) comes into contact with the field to level the field.

In addition, as the rear cover 12, a type in which a leveling member is detachably attached to the lower end side may be employed.
The left and right side covers 13 are fixed to the side frames 7L and 7R on the same side in the left-right direction.
Further, in the rotary cultivator 1, a pair of left and right cover lowering devices 19A, 19B that urge the rear cover 12 downward (bias in the grounding direction) are provided on the machine frame 2 side. The mounting portion 17 is provided over the rear mounting portion 18 provided on the back surface of the rear cover 12.

The front mounting portions 17 are disposed on both the left and right sides of the gear case 5 and are respectively fixed to the support arms 6. In the present embodiment, the front mounting portions 17 are composed of a pair of left and right plate members 17a disposed at intervals in the left-right direction. ing.
In addition, the front attachment part 17 should just be provided in the machine frame 2 side, for example, may be provided in the upper surface side of the upper cover 11. FIG.
Reinforcing members 20 are respectively provided on the rear sides of the left and right front mounting portions 17, and each of the left and right reinforcing members 20 is formed of a plate material and is fixed to the back surface of the rear cover 12, and is spaced apart in the left-right direction. The left and right side walls 21 are arranged, and a connecting wall 22 that connects the left and right side walls 21 is provided.

The upper side (front side) of the left and right side walls 21 of the reinforcing member 20 is formed so as to protrude from the rear cover 12 toward the back side, and the upper side of the left and right side walls 21 of the reinforcing member 20 is the rear mounting portion 18. It is said that.
As shown in FIGS. 1, 2, and 4 to 7, the left and right cover lowering devices 19 </ b> A and 19 </ b> B are provided across the front mounting portion 17 and the rear mounting portion 18 on the same side in the left-right direction. .
As shown in FIGS. 1 and 4 to 7, one cover lowering device 19 </ b> A includes a support rod 25 </ b> A projecting from the machine frame 2 toward the rear cover 12, and a longitudinal direction of the support rod 25 </ b> A. A screw shaft 26 that is arranged and rotatably held around the shaft center, a lift 27 that is movable in the longitudinal direction of the support rod 25A and non-rotatably supported on the rear cover 12 side of the support rod 25A, and a support rod A holder 28A that is movably held in the longitudinal direction of the support rod 25A is provided on the front side (machine frame 2 side) of the lift 27 of 25A.

The support rod 25A is formed in a cylindrical shape, and an opening window 31 in the longitudinal direction of the support rod 25A formed by opening a part of the circumferential direction of the support rod 25A is provided on the rear side of the support rod 25A. The front end side of the support rod 25A is connected to the front mounting portion 17 through the mounting body 33 and the support shaft 34 so as to be swingable about the rotation axis S2 in the left-right direction.
The mounting body 33 is formed in a cylindrical shape, and has a front small tube portion 37 and a rear large tube portion 38, and the small tube portion 37 has a front large diameter hole 39, an intermediate small diameter hole, and a rear large diameter hole in the axial direction. 41, and the fitting hole 42 is formed in the left-right direction so as to be orthogonal to the intermediate small-diameter hole. A small cylindrical portion 37 of the mounting body 33 is disposed between the left and right plate members 17 a constituting one front mounting portion 17.

The support shaft 34 is arranged over the left and right plate members 17 a constituting one front mounting portion 17, and an axial insertion hole 45 is provided at the center of the inner end portion of the support shaft 34. The left and right end portions of the support shaft 34 are inserted into support holes 35 formed in the left and right plate members 17 a of the one front mounting portion 17, and the center portion in the left and right direction of the support shaft 34 has a fitting hole 42 in the mounting body 33. Accordingly, the attachment body 33 is supported by the front attachment portion 17 via the support shaft 34 so as to be rotatable around the rotation axis S2.
The front end side of the support rod 25A is fitted into the large tube portion 38 of the mounting body 33 and is prevented from being detached by a spring pin or the like, and is fixed to the rear portion of the mounting body 33.

With this configuration, the front end side of the support rod 25A is supported by the front mounting portion 17 so as to be swingable about the rotation axis S2 and immovable in the axial direction of the support rod 25A.
The front side of the screw shaft 26 in the axial direction is formed to have a smooth outer surface, and a male screw portion 48 is formed on the outer peripheral surface from the midway portion of the screw shaft 26 in the axial direction to the rear end portion. The screw shaft 26 is inserted and held in the support rod 25A so as to be rotatable about its axis. The front side of the screw shaft 26 is inserted through the attachment body 33 in the axial direction through the front large-diameter hole 39, the intermediate small-diameter hole, and the rear large-diameter hole 41, and the shaft is inserted into the support shaft 34 through the insertion hole 45. The front end of the screw shaft 26 protrudes to the front side of the mounting body 33. The bearing 40 and the boss 44 of the handle 43 are sequentially fitted on the front end portion of the screw shaft 26, and the bearing 40 is fitted and held in the front large-diameter hole 39 of the mounting body 33. By fixing the boss 44 of the handle 43 to the screw shaft 26 with a pin, the screw shaft 26 is prevented from being pulled out from the mounting body 33 to the rear side, and the screw shaft 26 has a rear large-diameter hole 41 in the mounting body 33. A spring pin 49 that is in contact with the front opening edge is inserted, and the screw shaft 26 is prevented from coming off to the front side with respect to the mounting body 33.

As a result, the screw shaft 26 is restrained from moving in the longitudinal direction of the support rod 25A with respect to the support rod 25A and is rotatably held around the axis, and the screw shaft 26 is rotatable around the axis. In addition, it is supported so as to be swingable integrally around the support rod 25A and the rotation axis S2, but not movable in the axial direction.
As shown in FIG. 8, the lift 27 supports an inner fitting portion 51 that fits inside the support rod 25 </ b> A, an outer fitting portion 52 that fits outside the support rod 25 </ b> A, and the inner fitting portion 51 and the outer fitting portion 52. It has the connection part 53 connected via the opening window 31 of the collar 25A. The lift 27 is held movably in the longitudinal direction of the support rod 25A by fitting the inner fitting portion 51 and the outer fitting portion 52 of the lift 27 to the support rod 25A, and to the opening window 31 of the support rod 25A of the connecting portion 53. The lift 27 is held so as to be unrotatable around the shaft center by the fitting, and a screw hole 54 into which the screw shaft 26 is screwed is provided in the inner fitting portion 51 of the lift 27. The lift 27 is screwed to the screw shaft 26, and the lift 27 is moved in the longitudinal direction of the support rod 25A by the rotation of the screw shaft 26 around the axis. A spring pin 55 is inserted and held behind the lift 27 at the rear end of the screw shaft 26, and the spring pin 55 prevents the lift 27 from coming off from the support rod 25A and the rear end of the screw shaft 26. .

The holder 28A is externally fitted to the rear cover 12 side of the support rod 25A so as to be movable in the longitudinal direction of the support rod 25A. The holder 28A is supported by the rear mounting portion 18 via a pair of left and right cylindrical support shafts 56 projecting outward in the left-right direction so as to be rotatable about the rotation axis S1 in the left-right direction. The rear cover 12 is connected to the holder 28A so that the rear cover 12 moves up and down by movement in the longitudinal direction of the support rod 25A.
A spring 29A is provided to press the holder 28A toward the rear cover 12 (lift 27) to urge the rear cover 12 in the grounding direction. The spring 29A is constituted by a coil spring, and is externally held in a compressed state between a holder 28A of the support rod 25A and a spring receiving member 57A described later.

The holder 28A is held closer to the machine frame 2 than the lift 27 of the support rod 25A. When the holder 28A is pressed against the lift 27 by the bias of the spring 29A, the lift 27 causes the rear of the holder 28A ( The movement of the rear cover 12 to the grounding direction is changed in accordance with the movement position of the lift 27 in the longitudinal direction of the support rod 25A. It has become.
On the machine casing 2 side (front side) of the support rod 25A, a spring receiving member 57A for regulating the position of the front end of the spring 29A is externally held so as to be movable and adjustable in the longitudinal direction of the support rod 25A. The spring receiving member 57A is disposed on the front side of the spring 29A and, as shown in FIG. 12, is formed on the main body 61 that is externally fitted to the support rod 25A so as to be movable in the axial direction, and on the upper surface side of the support rod 25A. A key member 63 that engages with the engagement groove 62 to restrict the longitudinal movement of the support rod 25A of the main body 61 and a spring 64 that biases the key member 63 in a direction to engage with the engagement groove 62 are provided. . A plurality of engaging grooves 62 are formed at intervals in the axial direction of the support rod 25A.

The main body 61 is formed with an insertion hole 65 for inserting the support rod 25 </ b> A, a key accommodating portion 66 for accommodating the key member 63, and a spring accommodating portion 67 for accommodating the spring 64.
The key accommodating part 66 and the spring accommodating part 67 are formed in an open shape at the lower end so that the key member 63 and the spring 64 can be inserted from below.
In the spring receiving member 57A configured as described above, the key member 63 rotates integrally with the main body 61 by rotating the main body 61 about the axis of the support rod 25A, and supports the spring 64 against the urging force of the spring 64. The collar 25A moves outward in the radial direction and rides on the portion where the engagement groove 62 is not formed, so that it can be detached from the engagement groove 62, and the spring bearing member 57A can be moved in the longitudinal direction of the support collar 25A. It is configured.

1 and 4 to 6, an assist spring 81 is provided in the support rod 25 </ b> A for assisting the lift 27 to move in the direction in which the rear cover 12 is raised. As shown in FIG. 10, the assist spring 81 is constituted by a tension coil spring and is fitted into the support rod 25 </ b> A in a state of being fitted on the screw shaft 26. A hook portion 82 that protrudes backward in an L shape is provided at the rear end portion of the assist spring 81, and the front end side of the assist spring 81 is linearly extended forward and bent into an arc shape at the front end portion. 83 is provided.
A stay 85 is provided on the lift 27 so as to project forward corresponding to the opening window 31. The stay 85 is formed in a cylindrical shape having a locking hole 86 and is fixed to the outer fitting portion 52 to the connecting portion 53 of the lift 27 by welding or the like. A notch recess 88 corresponding to the stay 85 is provided in the rear part of the holder 28A, and when the holder 28A comes into contact with the lift 27 from the front side, the holder 28A can be fitted into and removed from the stay 85 via the notch recess 88 from the rear side. It is designed to fit.

  The rear end of the assist spring 81 is connected to the lift 27 by hooking the hook portion 82 of the assist spring 81 to the stay 85. The hook portion 83 of the assist spring 81 is hooked detachably from the front side on a locking pin 89 projecting inwardly at the front portion of the support rod 25A, and the rear end of the assist spring 81 is connected to the front portion of the support rod 25A. ing. As a result, when the lift 27 is located at the rear end position P2 of the support rod 25A from the midway position P1 in the front-rear direction of the support rod 25A shown in FIG. 1, the assist spring 81 extends back and forth. Pulls the lift 27 toward the machine frame 2 and biases the lift 27 toward the machine frame 2 (holder 28A), whereby the assist spring 81 moves in a direction in which the lift 27 raises the rear cover 12. Is to assist. When the lift 27 moves forward from the midway position P1 as shown in FIG. 1, the hook portion 83 of the assist spring 81 is disengaged from the locking pin 89 and moves further forward than the locking pin 89. Returns to the free length and the spring assist force becomes zero. The locking pin 89 is protruded inward from the front portion of the support rod 25A by being fitted and fixed in a mounting hole 90 provided at the front portion of the support rod 25A.

  In addition, when assembling the cover lowering device 19A, the screw shaft 26 and the assist spring 81 can be incorporated into the support rod 25A, for example, as follows. With the assist spring 81 fitted on the screw shaft 26, the screw shaft 26 is inserted from the rear end side of the support rod 25A together with the assist spring 81, and the front end portion of the screw shaft 26 is inserted from the rear end of the support rod 25A. Project forward. Thereafter, the holder 28 </ b> A and the lift 27 are externally fitted to the support rod 25 </ b> A from the rear end, the screw shaft 26 is rotated, and the lift 27 is screwed to the rear end side of the screw shaft 26. The hook portion 82 of the assist spring 81 is engaged. Then, the screw shaft 26 is rotated to move the lift 27 and the assist spring 81 together with the holder 28 to the front side of the support rod 25A, and then the hook portion 83 of the assist spring 81 is attached to the locking pin 89. The locking pin 89 is fitted and inserted into the mounting hole 90 of the support rod 25A by moving forward from the hole 90, and the locking pin 89 is protruded inward into the support rod 25A. As a result, when the screw shaft 26 is rotated to move the lift 27 backward, the hook portion 83 engages with the locking pin 89 and the assist spring 81 is pulled rearward to extend the lift 27 to the front side. Will be energized.

As shown in FIG. 11, the other cover lowering device 19B is fixedly fitted to the support cover 25B projecting from the machine frame 2 toward the rear cover 12, and to the end of the support cover 25B on the rear cover 12 side. And a holder 28B held movably in the longitudinal direction of the support rod 25B on the machine frame 2 side from the stop ring 71 of the support rod 25B.
The holder 28B is supported by the rear mounting portion 18 via the support shaft 56 so as to be rotatable around the rotation axis S1 in the left-right direction. As a result, the holder 28B is moved in the longitudinal direction of the support rod 25B by the up-and-down movement of the rear cover 12. The holder 28B and the rear cover 12 are connected so as to move. A spring 29B is provided to press the holder 28B toward the stop ring 71 in order to urge the rear cover 12 in the grounding direction.

The support rod 25B is formed in a cylindrical shape, and a plurality of engagement grooves 62 are formed at intervals in the axial direction of the support rod 25B. The front end side of the support rod 25B is connected to the front mounting portion 17 by a mounting pin 72 so as to be swingable about the rotation axis S2 in the left-right direction.
The mounting pin 72 is inserted into the left and right plate members 17a of the front mounting portion 17 and the front end portion of the support rod 25B, and is prevented from coming off by a snap pin 73. A retaining ring 75 is fitted and fixed to the rear side of the front mounting portion 17 of the support rod 25B.
The holder 28B is externally fitted on the rear cover 12 side of the support rod 25B so as to be movable in the longitudinal direction of the support rod 25B, and a spring 29B is constituted by a coil spring, between the holder 28B of the support rod 25B and the spring receiving member 57B. The outer fit is held in a compressed state.

  On the machine casing 2 side (front side) of the support rod 25B, a spring receiving member 57B for regulating the position of the front end of the spring 29B is externally held so as to be movable and adjustable in the longitudinal direction of the support rod 25B. The spring receiving member 57B is disposed on the front side of the spring 29B, is configured in the same manner as the spring receiving member 57A of the one cover lowering device 19A, and includes a main body 61, a key member 63, and a spring 64. By rotating 61 around the axis of the support rod 25B, the key member 63 rotates integrally with the main body 61 and moves outward in the radial direction of the support rod 25B against the biasing force of the spring 64. By climbing over a portion where 62 is not formed, the engagement groove 62 is disengaged and the spring receiving member 57B can be moved in the longitudinal direction of the support rod 25B (see FIG. 12).

According to the above-described embodiment, the screw shaft 26 is rotated around the axis by the handle 43 of the one cover lowering device 19A, and the lift 27 is moved to the rear of the support rod 25A. As shown in FIG. 2, the holder 28A is pushed forward by the lift 27, and as a result, the rear cover 12 swings upward around the support shaft 16 from the state where it hangs downward.
In this case, as shown in FIG. 2, if the lift 27 is in the rear end position P2 from the midway position P1 shown in FIG. 1 with the rear cover 12 hanging downward, the assist spring 81 is extended back and forth. Then, the lift 27 is urged toward the machine frame 2 and the assist spring 81 assists the lift 27 to move in the direction of raising the rear cover 12, so that the screw shaft 26 is rotated by operating the handle 43. When the lift 27 is moved in the direction of raising the rear cover 12 with respect to the support rod, mud adheres to the back surface of the rear cover 12, or mud accumulates on the upper surface of the rear cover 12, and the rear cover Even if the weight of the entire body 12 increases, the rear cover 12 can be lifted smoothly by rotating the screw shaft 26 with a light force.

  Further, when the rear cover 12 exceeds the horizontal state shown in FIG. 2 and the lift 27 moves forward from the midway position P1 as shown in FIG. 1, the hook portion 83 of the assist spring 81 is disengaged from the locking pin 89. Since the assist spring 81 returns to a free length and the spring assist force becomes zero because it moves forward from the locking pin 89, the rear cover is raised rearward beyond the horizontal state at this time. Since the weight of the cover 12 is supported by the upper cover 11 and the like, and the load of the rear cover 12 is not greatly applied to the lift 27 side, the screw shaft 26 is rotated with a light force to keep the rear cover 12 smoothly. Can be lifted.

On the other hand, when the screw shaft 26 is rotated around the shaft center by the handle 43 and the lift 27 is moved to the rear of the support rod 25A, the rear cover 12 swings downward by its own weight.
In the case of normal tilling, the lift 27 of one cover lowering device 19A is moved to the rear end of the support rod 25A.
At the time of this normal tillage, the rear cover 12 has a forward inclined posture in which the rear cover 12 is moved downward as the ground contact portion on the lower end side comes into contact with the ground, and the springs 29A and 29B are springs. It is compressed between the receiving members 57A and 57B and the holders 28A and 28B to urge the rear cover 12 in the grounding direction.

At this time, the urging force with respect to the rear cover 12 can be changed by moving the spring receiving members 57A, 57B in the longitudinal direction of the support rods 25A, 25B and engaging the key member 63 with the other engaging groove 62. .
In the normal tillage state, the holders 28A and 28B can move in the longitudinal direction with respect to the support rod 25A of the one cover lowering device 19A, so that the rear cover 12 can swing up and down according to the tilling depth. It is.
Further, when plowing with the grounding portion of the rear cover 12 floating from the ground, the lift 27 of one cover lowering device 19A is moved forward until the grounding portion of the rear cover 12 floats from the ground. The lower limit position of the vertical swing range of the rear cover 12 is set to a desired position.

In addition, since the cover lowering device 19A has a structure in which the rear cover 12 is adjusted up and down by screwing the screw shaft 26 and the lift 27, the vertical swing position of the rear cover 12 is adjusted steplessly. The rear cover 12 can be held at an arbitrary position, and the vertical swing position of the rear cover 12 can be adjusted with high accuracy according to the working conditions.
Further, during maintenance, the lift 27 of one cover lowering device 19A is moved to the front side.
In the above-described embodiment, the adjustment of the vertical swing position of the rear cover 12 at the time of plowing and maintenance while the grounding portion of the rear cover 12 is slightly lifted from the ground is all made to rotate the screw shaft 26. Therefore, it is easy to operate and can be used without instructions, and it is not necessary for the operator to manually lift the rear cover 12 as in the prior art, so that the work labor can be reduced.

Further, in the conventional cover de-balling device, since the lock pin and the spring member are incorporated in the holder, the structure is complicated, and the lock hole must be formed in the rod member. In this case, there is no such problem, and the structure can be simplified as compared with the conventional cover bouncing device.
Further, according to the above embodiment, as disclosed in Japanese Patent Application No. 2006-006218 and Japanese Patent Application No. 2006-138194, a support rod (outer cylinder) and an inner cylinder that moves in and out of the support rod. And a screw shaft that is rotatably inserted into and held by the support rod and is screwed into a lift (nut body) fixed to the inner cylinder, and the screw shaft is rotated by a handle so that the support rod On the other hand, the cover retracting device of the present invention has the supporting rods 19A and 19B and the supporting rod 25A as the main members as compared with the screw type expansion and contraction structure in which the inner cylinder is moved back and forth to expand and contract. , 25B, a lift shaft 27 which is held in a movable manner in the longitudinal direction of the support rods 19A, 19B, and the like. Shaft 26 and support rod 19A, 1 Only by moving in the longitudinal direction with respect to B, the entire length of the cover lowering device 19A, 19B does not expand and contract as in the past, and the cover lowering device 19A, 19B can be installed easily and compactly.

In the rotary cultivator 1 described above, the main parts such as members and mechanisms that are normally equipped on the rotary cultivator 1 are disclosed, and other members that are normally equipped that are not related to the present invention, The mechanism and the like are omitted.
13 and 14 show another embodiment, and the front mounting portion 17 and the rear mounting portion are arranged so that the cover lowering devices 19A and 19B are reversed in the front-rear direction with respect to the embodiment of FIGS. 18 are provided.
That is, as shown in FIG. 13, the support rod 25A of the cover lowering device 19A is projected from the rear cover 12 toward the machine frame 2, and the lift 27 is located on the side of the machine frame 2 of the support rod 25A. 25A is movable in the longitudinal direction and is held non-rotatable. The holder 28A is held movably in the longitudinal direction of the support rod 25A on the rear side (rear cover 12 side) of the lift 27 of the support rod 25A.

  The rear end side of the support rod 25A is connected to the rear attachment portion 18 via the attachment body 33 and the support shaft 34 so as to be swingable about the rotation axis S2 in the left-right direction. The rear cover 12 is connected to the mounting body 33 so that the rear cover 12 moves up and down by the movement in the direction, and the holder 28A is pressed to the front side (lift 27 side) by the spring 29A to bring the rear cover 12 into the grounding direction. It is trying to be energized. The handle 43 is provided at the rear end portion of the screw shaft 26 (the cover lowering device 19A) via the boss portion 44, and the screw shaft 26 is pivoted by rotating the handle 43 from the rear side of the rotary cultivator 1. The screw shaft 26 and the support rod 25A are moved in the longitudinal direction with respect to the lift 27 by rotating around the center, whereby the rear cover 12 is moved up and down. Therefore, the handle 43 is disposed on the rear side of the support rod 25A and above the rear cover 12. In addition, an assist spring 81 that assists the lift 27 moving in the direction of raising the rear cover 12 is provided in the support rod 25A, and the front end of the cyst spring 81 is connected to the lift 27, and the hook portion 83 of the assist spring 81 is provided. Is hooked detachably from the rear side to a locking pin 89 projecting inwardly at the rear portion of the support rod 25A, and the front end of the assist spring 81 is connected to the rear portion of the support rod 25A. As a result, when the lift 27 is on the front side of the support rod 25A, the lift 27 is urged toward the rear cover 12, so that the assist spring 81 moves in a direction in which the lift 27 raises the rear cover 12. It comes to assist. When the lift 27 moves to the rear side of the support rod 25A, the hook portion 83 of the assist spring 81 is disengaged from the latch pin 89 and moves rearward from the latch pin 89, so that the assist spring 81 has a free length. The return spring assist force is configured to be zero.

Further, as shown in FIG. 14, the support rod 25B of the other cover lowering device 19B protrudes from the rear cover 12 toward the machine frame 2, and the retaining ring 71 is the end of the support rod 25B on the machine frame 2 side. The holder 28B is held on the front side (rear cover 12 side) of the support collar 25B so as to be movable in the longitudinal direction of the support collar 25B.
The holder 28B is externally fitted on the side of the frame 2 of the support rod 25B so as to be movable in the longitudinal direction of the support rod 25B. The holder 28B is attached to the front mounting portion 17 via the support shaft 56 around the rotation axis S1 in the left-right direction. The holder 28B and the machine casing 2 are connected so that the support rod 25B is moved in the longitudinal direction with respect to the holder 28B by the up-and-down movement of the rear cover 12.

On the rear cover 12 side (rear side) of the support rod 25B, the spring receiving member 57B is fitted and held so as to be movable and adjustable in the longitudinal direction of the support rod 25B, and the holder 28B is moved to the front side to urge the rear cover 12 in the grounding direction. A spring 29B that presses toward the retaining ring 71 is provided between the holder 28B and the spring receiving member 57B.
The rear end side of the support rod 25B is connected to the rear mounting portion 18 by a mounting pin 72 so as to be swingable about the rotation axis S2 in the left-right direction. The attachment pin 72 is inserted into the left and right plate members 18 a of the rear attachment portion 18 and the rear end portion of the support rod 25 </ b> B, and is prevented from being detached by a snap pin 73. A retaining ring 75 is fitted and fixed to the rear side of the rear mounting portion 18 of the support rod 25B.

The other points are the same as those in the above embodiment.
According to the above embodiment, as in the case of the embodiment of FIGS. 1 to 12, when the rotary tiller 3 and the like are maintained, the screw 27 is rotated around the axis to thereby lift the lift 27. The rear cover 12 can be lifted greatly by moving it in the longitudinal direction of the support rod 25A, so that the rear cover 12 does not have to be lifted directly by hand, and work labor can be reduced.
In this case, the assist spring 81 assists the lift 27 to move in the direction of raising the rear cover 12 with the rear cover 12 hanging downward, so that the screw shaft 26 is rotated by operating the handle 43. When the lift 27 is moved in the direction in which the rear cover 12 is raised with respect to the support rod, mud adheres to the back surface of the rear cover 12 or mud accumulates on the upper surface of the rear cover 12, and the rear cover 12 as a whole. Even if the weight of the rear cover 12 increases, the rear cover 12 can be lifted smoothly by rotating the screw shaft 26 with a light force.

When the rear cover 12 exceeds the horizontal state, the hook portion 83 of the assist spring 81 is disengaged from the latch pin 89 and moves rearward from the latch pin 89, so that the assist spring 81 returns to a free length and assists the spring. Although the force is 0, at this time, since the rear cover is raised rearward beyond the horizontal state, the weight of the rear cover 12 is supported by the upper cover 11 and the like, and the load of the rear cover 12 is increased to the lift 27 side. Therefore, the rear cover 12 can be lifted smoothly by rotating the screw shaft 26 with a light force.
In addition, when plowing with the grounding portion of the rear cover 12 slightly lifted from the ground during plowing, the rear cover 12 swings upward by moving the lift 27 rearward with respect to the support rod 25A. Thus, the grounding portion of the rear cover 12 can be securely held in a state where it is slightly lifted from the ground, and the vertical position adjustment of the rear cover 12 can be adjusted continuously, and the lower limit position of the rear cover 12 can be adjusted. It can be set with high accuracy. Moreover, when the rear cover 12 is moved up and down, the lift 27 only moves in the longitudinal direction with respect to the screw shaft 26 and the support rod 25, and the entire length of the cover lowering devices 19A and 19B expands and contracts as in the conventional case. Therefore, the cover lowering devices 19A and 19B can be easily and compactly installed on the rotary tiller body.

Further, in the case of this embodiment, a handle 43 for rotating the screw shaft 26 is provided at the rear end portion of the screw shaft 26, and the handle 43 is behind the support rod 25 </ b> A and above the rear cover 12. If the handle 43 is on the front side of the screw shaft 26 or the support rod 25A, there is a risk of interference with the tractor tire or lower link, but the handle 43 is arranged above the wide rear cover 12. Therefore, there is no possibility of interference with an external member when the handle 43 is operated, and the handle 43 can be easily operated.
In the above-described embodiment, the support rod 25A is formed in a cylindrical shape, and the screw shaft 26 is inserted and held in the support rod 25A so as to be rotatable about the axis. However, the screw shaft 26 is in the longitudinal direction of the support rod 25A. The support rod 25A is not limited to a cylindrical shape, as long as the support rod 25A is moved along the longitudinal direction of the support rod 25A and restricted to move in the longitudinal direction of the support rod 25A. For example, the support rod 25A is formed in a rod shape, the screw shaft 26 is formed in a cylindrical shape, and the screw shaft 26 is externally fitted to the support rod 25A, whereby the screw shaft 26 is fitted in the longitudinal direction of the support rod 25A. And the movement of the support rod 25A in the longitudinal direction may be restricted and the shaft may be held so as to be rotatable about the axis.

  In the above embodiment, the holder 28A is held on one side of the machine frame 2 or the rear cover 12 with respect to the lift 27 of the support rod 25A, and the holder 28A is pressed against the lift 27 by the bias of the spring 29A. By doing so, the movement restriction position of the rear cover 12 in the grounding direction varies according to the movement position of the lift 27 in the longitudinal direction of the support rod 25A, so that the other side of the machine frame 2 or the rear cover 12 of the holder 28A is moved by the lift 27. However, instead of this, as disclosed in Japanese Patent Application No. 2006-006218 and Japanese Patent Application No. 2006-138194, the inner cylinder is moved into and out of the support rod 25A. An inner cylinder body that is freely fitted and held is provided, and a lift 27 is fixed to the inner cylinder body so that the inner cylinder body moves forward and backward in the longitudinal direction of the support rod 25A together with the lift 27. The rear cover 12 is constructed according to a screw-type telescopic structure, and the holder 28A is elastically supported on the inner cylinder body via the spring 29A and the like, so that the lift 27 has a longitudinal position of the support rod 25A. The movement restriction position of the holder 28 </ b> A in the ground contact direction may be changed by the lift 27 to restrict the movement of the holder 28 </ b> A to the other side of the machine casing 2 or the rear cover 12.

  In the above-described embodiment, when the lift 27 is rearward or forward from the midway position P1 in the front-rear direction of the support rod 25A, the assist spring 81 moves in a direction in which the lift 27 raises the rear cover 12. When assisting and the lift 27 moves forward or backward from the midway position P1, the assist spring 81 returns to a free length and the spring assist force becomes zero. Instead, the lift 27 is supported by the lift 27. The assist spring 81 is extended in the front-rear direction at any position in the front-rear direction of the collar 25A, and the assist spring 81 is configured to assist the movement of the lift 27 in the direction in which the rear cover 12 is raised. May be. Further, the assist spring 81 can be constituted by a compression coil spring instead of the tension coil spring.

It is side surface sectional drawing of one cover bouncing apparatus which shows one Embodiment. It is a side view of the rotary tiller. It is a top view of the rotary tiller. It is side surface sectional drawing of the front part of the same one cover lowering apparatus. It is side surface sectional drawing of the middle part of the front-back direction of the same one cover lowering apparatus. It is side surface sectional drawing of the rear part of the same cover lowering apparatus. It is a plane sectional view of the front part of the same cover lowering device. It is the sectional view on the AA line of the same FIG. It is the BB sectional view taken on the line of FIG. It is a side view of the assist spring. The front end portion of the other cover lowering device is a cross-sectional configuration diagram in which the front end portion is a plan cross-sectional view and the rear side is a side cross-sectional view. It is side surface sectional drawing of the same spring receiving member part. It is side surface sectional drawing of one cover lowering apparatus which shows other embodiment. In the other cover lowering device, the rear end portion is a cross-sectional plan view and the front side thereof is a side cross-sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary cultivator 2 Machine frame 3 Rotary cultivating part 11 Upper cover 12 Rear cover 17 Front attachment part 18 Rear attachment part 19A One cover retracting device 25A Support rod 26 Screw shaft 27 Lift 28A Holder 29A Spring 31 Opening window 51 Internal fitting Part 52 outer fitting part 53 connecting part 54 screw hole 57 spring receiving member 81 assist spring S1 rotation axis

Claims (5)

The machine frame (2) is provided with a rotary tiller (3) for tilling the field, and an upper cover (11) covering the upper side of the rotary tiller (3), on the rear end side of the upper cover (11). A rear cover (12) pivotally connected to be pivotable about a horizontal axis is provided, and the rear cover (12) is attached to the grounding direction across the rear cover (12) side and the machine frame (2) side. In a rotary cultivator provided with a cover lowering device (19A)
The cover lowering device (19A) is arranged along the longitudinal direction of the support rod (25A) projecting from one of the machine frame (2) or the rear cover (12) toward the other and the support rod (25A). The screw shaft (26) whose movement is restricted in the longitudinal direction of the support rod (25A) and rotatably held around the axis, and the machine frame (2) or the rear cover (12) of the support rod (25A). On the other side, a lift (27) that is movable in the longitudinal direction of the support rod (25A) and is held non-rotatable, and a holder (28A) that is held so as to be movable in the longitudinal direction of the support rod (25A) are provided. ,
The lift (27) is screwed onto the screw shaft (26) so that the lift (27) moves in the longitudinal direction of the support rod (25A) by rotation around the axis of the screw shaft (26), and the holder (28A) The other of the machine frame (2) or the rear cover (12) is connected to the holder (28A) so that the rear cover (12) moves up and down by the movement in the longitudinal direction of the support rod (25A), and the lift (27) The machine frame (2) or the rear cover of the holder (28A) is lifted by a lift (27) so that the movement restriction position of the rear cover (12) in the grounding direction varies according to the movement position of the support rod (25A) in the longitudinal direction. (12) is configured to restrict movement of the rear cover (12) to the other side, and the holder (28A) is placed on the other side of the machine frame (2) or the rear cover (12) to urge the rear cover (12) in the grounding direction. Spring (29A) pressing toward An assist provided to bias the lift (27) toward one side of the machine frame (2) or the rear cover (12) to assist the lift (27) to move in the direction of raising the rear cover (12). A rotary tiller characterized in that a spring (81) is provided.   The holder (28A) is held on one side of the machine frame (2) or the rear cover (12) with respect to the lift (27) of the support rod (25A), and the holder ( 28A) is pressed against the lift (27) so that the movement restriction position of the rear cover (12) in the grounding direction varies depending on the movement position of the support rod (25A) in the longitudinal direction of the lift (27). The rotary according to claim 1, wherein the lift (27) is configured to restrict movement of the holder (28A) to the other side of the machine casing (2) or the rear cover (12). Cultivator.   A front mounting portion (17) is provided on the machine frame (2) side, a rear mounting portion (18) is provided on the rear cover (12) side, and the support rod (25A) is formed in a cylindrical shape and supported. An opening window (31) formed by opening a part in the circumferential direction of the flange (25A) is formed in the longitudinal direction of the support flange (25A), and is supported on one of the front mounting portion (17) or the rear mounting portion (18). The front end side or the rear end side of (25A) is swingably connected around the rotation axis (S2) in the left-right direction, and the screw shaft (26) is inserted and held in the support rod (25A) so as to be rotatable about the axis. The lift (27) includes an inner fitting portion (51) fitted into the support rod (25A), an outer fitting portion (52) fitted outside the support rod (25A), and an inner fitting portion (51). A connecting portion (53) for connecting the outer fitting portion (52) to the supporting rod (25A) via the opening window (31), and a lift (27 The lift (27) is held movably in the longitudinal direction of the support rod (25A) by fitting the inner fitting portion (51) and the outer fitting portion (52) to the support rod (25A), and the connecting portion (53 ) Is held in the opening window (31) of the support rod (25A) so that the lift (27) cannot be rotated around the shaft center, and the screw shaft (26) is fitted to the internal fitting portion (51) of the lift (27). A screw hole (54) for screwing is provided, and the holder (28A) is externally fitted so as to be movable in the longitudinal direction of the support rod (25A). Rotary tiller.   A spring receiving member (57A) is fitted and held on one side of the machine casing (2) or the rear cover (12) of the support rod (25A) so as to be movable and adjustable in the longitudinal direction of the support rod (25A). 28A) is externally fitted to the machine frame (2) of the support rod (25A) or the other side of the rear cover (12) so as to be movable in the longitudinal direction of the support rod (25A), and the spring (29A) is constituted by a coil spring. The outer fitting is held in a compressed state between the spring receiving member (57A) of the support rod (25A) and the holder (28A). The described rotary cultivator.   The assist spring (81) is constituted by a tension coil spring, and is fitted into the support rod (25A) in a state of being fitted around the screw shaft (26), and the lift (27) is attached to the machine frame (2) or the rear part. The rotary cultivator according to any one of claims 1 to 4, wherein the rotary cultivator is configured to be pulled toward one side of the cover (12).

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