JPH0432010Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for attaching tilling claws used in a rotary tiller capable of forward and reverse rotation.

If the rotary tiller's claws collide with stones or drive into hard soil during tilling, a large load may be applied to the claw drive system, claw attachment parts, etc. For this reason, conventional unidirectional rotary tillers have a slip clutch or torque limiter built into their gear case or at the universal joint for connection to the tractor PTO shaft. Since incorporating such a slip clutch or torque limiter would complicate the structure and make it expensive, some claw shafts have a shock absorber such as rubber built into the end. However, even with this configuration, it is still expensive and can only cope with overload of the tilling section as a whole, and it is difficult to prevent damage to the individual tilling claws and their attachment parts.

Therefore, it is conceivable to pivotally support the tilling claws to the brackets of the claw shafts with bolts and passing through the shear pins, so that the overload transmission can be eliminated by each tilling claw. However, this method can be applied when the tilling claw is fixed to the claw shaft, and the working posture of one tilling claw is changed between up-cutting work and down-cutting work with respect to the claw shaft to achieve the best result. This is difficult to apply when swinging to match the driving angle.

In view of these various problems, the present invention pivots the tilling claw to the mounting body of the claw shaft, and
A claw attachment structure for a forward/reverse rotary tiller that prevents damage to the tiller claws, claw mounting parts, and drive system due to overload by using a shear pin as the member that holds the tiller claws in each forward and reverse working position. The purpose is to provide

The feature of the present invention for achieving this purpose is that the claw shaft 20, which can be freely switched between forward and reverse directions, is provided with a claw mounting body 21 perpendicular to the shaft center.
A tilling claw 2 having blade parts 25a and 25b for forward and reverse rotation.
2 is swingably supported around an axis parallel to the claw shaft 20, and in order to receive the reaction force of each forward and reverse tillage of the tilling claw 22, the tilling claw 22 is rotated in forward and reverse directions away from the position where it contacts the claw shaft 20. A claw attachment structure for a forward/reverse rotary tiller in which members for holding the tilling claws 22 in the respective postures A and B are provided on the claw mounting body 21, and the members for holding the tilling claws 22 in the respective postures A and B are attached to the claw shaft 20. It is located at a point formed by a shear pin 35 located radially outwardly from the center.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of a forward/reverse rotary tiller 1. This rotary tiller 1 is mainly composed of a machine frame 2, a tiller section 3, a tiller cover device 4, and the like. It is mounted so that it can be raised and lowered via a point linkage mechanism.

The machine frame 2 includes support arms 6 protruding from the left and right sides of a gear case 5 incorporating a forward/reverse gear transmission mechanism, and a transmission case 7 and a side frame 18 fixed to the outer end of each support arm 6. ing. 8 is an input shaft protruding forward from the gear case 5; 9 is a transmission shaft that transmits power from the input shaft 8 to the transmission case 7; 10 is a support frame extending rearward from the machine frame 2; It supports a gauge wheel 11, and its angle can be freely adjusted by a height adjustment mechanism 12.

The tillage cover device 4 includes a main cover 13 fixed to the machine frame 2, a rear cover 14 pivoted to the rear end of the main cover 13, and a pair of left and right side covers 15. Equal pressure adjustment mechanism 1
It is suspended by 6. Also, main cover 1
A reiki 17 is attached to the rear end of the tiller 3 so as to be able to adjust its angle, and is positioned between the rear cover 14 and the tilling section 3 to prepare the tilled soil into a fine surface layer and a sub-layer soil clod shape.

The tilling section 3 has a pawl shaft 20 supported by the transmission case 7 and the side frame 18 so as to be rotatable around a horizontal axis, and a pawl mounting body 21 fixed to the pawl shaft 20 at right angles to the axis. It has a large number of tilling claws 22 attached thereto, and the claw shaft 20 can be freely switched between forward and reverse directions by power from the gear case 5.

The tilling claw 22 has an arc-shaped forward rotation blade portion 25a and a reverse rotation blade portion 25b on the front and rear edges in the rotation direction, and a swing hole 26a is formed in the mounting base 26, so that the tip of the nail can be seen from the front. It is bent into a letter shape.

In Figs. 1 to 4, the claw attachment body 21 is constructed by fitting mounting plates 23 and 24, which are approximately elliptical in side view, onto the claw shaft 20 and welding them at intervals. A mounting base 26 of the claw 22 is inserted, and is supported by a fixture 27 so as to be swingable about an axis parallel to the claw shaft 20.

The fitting 27 includes a bolt 28 and a nut 2.
9, a cylindrical shaft 30 fitted to the bolt 28, and a pair of disc springs 31. The flange portion 30a of the cylinder shaft 30 faces the mounting plate 23, and the large diameter portion 30
b fits into the large diameter hole 23a of the mounting plate 23, and the cylindrical part 30c passes through the swing hole 26a of the tilling claw 22 and engages with the notch 24a of the mounting plate 24, and the bolt 28 that passes through it. By screwing together the nut 29, the cylinder shaft 30 is fixed to the mounting plates 23, 24.

A pair of disc springs 31 have a large diameter portion 30b and a tilling claw 22.
and between the large-diameter hole 23a and the cylindrical portion 30c, and by fixing the cylindrical shaft 30 to the mounting plate 24, it provides the tilling claws 22 with the required frictional resistance. 32 is a friction plate.

Further, the pawl attachment body 21 is provided with two shear pins 35 located apart from the pawl shaft 20 in the radial direction. Each shear pin 35a, 35b regulates the swing range of the tilling claw 22.
A recess 36 formed at the front and rear of the mounting base 26 of
two mounting plates 23, 24 and reinforcing tubes 37, 38 welded to their outer surfaces.
It penetrates through.

The shear pin 35 has a cut portion 39 at approximately the center facing the tilling claw 22, and this cut portion 39
has a smaller diameter than other parts and is longer than the thickness of the tilling claw 22,
The shape is such that it can be pulled out from the claw attachment body 21 even if it curls during cutting. Further, an annular groove 40 is formed on the outer peripheral surface of the reinforcing cylinder 37 of the shear pin 35.

An annular recess 41 is formed on the outer circumferential surface of the reinforcing cylinder 32 at a position corresponding to the annular groove 40 of the shear pin 35. A part of this annular recess 41 becomes a deep groove 41a that reaches the annular groove 40, and is reinforced from the annular recess 41. An introduction groove 41b is formed to be inclined toward the outer end surface of the cylinder 37.

Reference numeral 42 denotes a retaining member formed from a single spring steel wire, which includes a straight portion 42 a that enters the deep groove portion 41 a and engages with the annular groove 40 , a circular arc portion 42 b that engages with the annular recess 41 , and an annular recess 41 . Introductory groove 41b
The reinforcing cylinder 37, the retaining member 42, and the annular groove 40 constitute a retaining mechanism 43 for the shear pin 35, which prevents the shear pin 35 from being withdrawn. When the stopper member 42 engages with the annular groove 40, the shear pin 35 is prevented from coming out, and by pushing the straight part 42a with a finger and separating it from the annular groove 40, the shear pin 35 is removed.
can be removed from the claw attachment body 21, and the shear pin 35 can be inserted and removed without using tools.

The tilling claws 22 are configured to be able to freely change their posture between a forward tilted posture A shown in solid lines in FIGS. 1 and 2 and a reverse tilted posture B shown in phantom lines in FIGS.

That is, when the claw shaft 20 is rotated in the normal direction for down-cutting tillage, the tilling claws 22 receive resistance during the first driving and swing around the fixture 27, causing the recess 36 to rotate.
A comes into contact with the shear pin 35a, thereby creating a normal rotation tilted posture A with a driving angle suitable for downcut tilling, and the tilling reaction force is received by the shear pin 35a. Furthermore, when the direction of rotation of the pawl shaft 20 is changed and reversed, the tilling pawl 22 swings during the first driving, and the recess 36b comes into contact with the shear pin 35b, thereby reversing the driving angle suitable for hard plowing. The tilted position is set to B, and the shear pin 35b
The tillage reaction force can be received by. That is, the shear pins 35a and 35b are members that hold the tilling claws 22 in forward and reverse positions A and B away from the position where they contact the claw shaft 20 in order to receive the respective forward and reverse tilling reaction forces of the tilling claws 22. When the shear pins 35a, 35b are cut, the tilling claws 22 only come into contact with the claw shafts 20 and do not rotate around the axis of the fixture 27.

In both forward and reverse positions, the tilling claws 22 tend to assume an intermediate position due to centrifugal force, that is, a position along the radial direction of the claw shaft 20, but the resistance force by the fixture 27 is large enough to prevent this. Furthermore, the frictional resistance force due to the disc spring 31 is set to be smaller than the driving reaction force.

Figure 5 shows the shear pin 35' and the retaining mechanism 4.
3' shows another example, in which the reinforcing cylinder 37' welded to the mounting plate 23 has a female thread 45 or a nut is used, and the shear pin 35' is made thin by cutting the tip of the bolt. things are used,
The male screw 46 is screwed into the female screw 45 to attach the shear pin 35' to the mounting body 21,
The female and male screws 45 and 46 serve as a retaining mechanism 43', and although a tool such as a spanner is required to insert and remove the shear pin 35', it is simple and inexpensive to manufacture. still,
In this case, the female thread 45 may be formed on the mounting plate 23 without providing the reinforcing tubes 37' and 38.

Figures 6 and 7 show the claw attachment body 21' and the tilling claw 2.
2' are shown, and the first one shown in FIG.
In this example, a circular plate is used for the claw attachment body 21', and the front and rear edges of the attachment base 26 of the tilling claw 22' have no recesses, and the straight portions abut the shear pins 35. In the second example shown in FIG. 7, the claw attachment body 21'' uses a substantially rectangular plate, and the recess 36 of the tilling claw 22'' is formed deeply.

Note that the claw attachment body 21 of the embodiment and the first example,
21' is designed to allow attachment of two tilling claws 22, but it is also possible to attach only one plowing claw, and since the driving angle can be changed by changing the depth of the recess 36 of the tilling claw 22, the size of the claw attachment body 21 can be changed. , shear pin 35
Determine the depth by taking into account the location, etc.

According to the present invention described in detail above, the member for holding the respective postures A and B of the tilling claws 22 is formed by the shear pin 35 located radially outward from the claw shaft 20, so that the tilling claws 22 are prevented from being overloaded. By cutting the shear pin 35, it is possible to prevent the tilling claw 22, the claw attachment body 21, the attachment 27, and the drive system from the tractor to the claw shaft 20 from being damaged. Since the shear pin 35 is supported by a pawl mounting body 21 provided on the pawl shaft 20 at right angles to the pawl shaft 20 so as to be able to swing around an axis parallel to the pawl shaft 20, when the shear pin 35 is cut, it hits the pawl shaft 20. Even if the shear pin is used without realizing that the shear pin has broken, it will only reduce tillage performance and prevent the swing shaft (attachment 27) from rotating around its center, causing damage to the swing shaft. Accidents such as scattering of tilling nails due to this can be prevented.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a cross-sectional side view of a forward and reverse rotary tiller, and FIG.
The figure is a side view of the main parts, Figure 3 is a sectional view taken along the line - - in Figure 2, Figure 4 is an exploded perspective view of the shear pin retaining structure, Figure 5 is a sectional view showing another example of the shear pin, Figure 6 is FIG. 7 is a side view showing another example of the mounting body and the tilling claw. 1... Rotary tiller, 20... Claw shaft, 21...
... Claw attachment body, 22 ... Cultivating claw, 25a ... Forward rotation blade section, 25b ... Reverse rotation blade section, 27 ... Attachment tool, 35 ... Shear pin, 43 ... Removal prevention mechanism,
A...Forward rotation working posture, B...Reverse rotation working posture.

Claims (1)

[Claims for Utility Model Registration] A claw attachment body 21 is provided on a claw shaft 20 that can be freely switched between forward and reverse directions at right angles to the shaft center, and a tilling claw 22 having blade parts 25a and 25b for forward and reverse rotation is attached to this claw attachment body 21. The tilling claws 22 are supported so as to be swingable about an axis parallel to the shaft 20, and in order to receive the reaction forces of the tilling claws 22 in the forward and reverse directions, the tilling claws 22 are moved in each forward and reverse direction away from the position where they contact the claw shaft 20. , B is a claw mounting structure for a forward/reverse rotary tiller in which members for holding the tilling claws 22 in the respective postures A and B are provided on the claw mounting body 21, and the members for holding the respective postures A and B of the tilling claws 22 are arranged radially outward from the claw shaft 20. A claw attachment structure for a forward/reverse rotary tiller, characterized in that it is formed of shear pins 35 located apart in the direction.