JPH0454725Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a claw holder that protrudes from the tilling shaft of a tiller in order to attach the claw to the tilling shaft of a tiller, and in particular, a claw holder that is provided with a fitting hole as a fitting part. Related to improvement of claw holder.

[Technical Background and Problems of the Invention] Conventionally, a claw holder having the above-mentioned insertion hole is
In order to form an insertion hole with a substantially uniform rectangular cross section in the longitudinal direction of the claw, two steel plates bent into a U-shape are combined and welded together as shown in Fig.
There is also one that is integrally molded as shown in the figure. The claw holder is radially fixed to the tilling shaft by welding, and the mounting portion on the claw side is fitted into the insertion hole of the claw holder and fixed with a set bolt to attach the claw to the tilling shaft and perform tilling work.

However, since the inner surface of the insertion hole is not finished, the effective contact area with the claw side is very small, resulting in extreme stress concentration. As a result, the slight contact portion on the inner surface of the insertion hole is partially deformed due to the severe repeated bending stress applied to the claw, causing play.
Even if an attempt is made to finish the inner surface of the insertion hole in order to improve this condition, it is extremely difficult to finish the inner surface of the insertion hole because of the narrow and elongated shape. Further, the welded claw holder is particularly susceptible to cracking under the concentrated load under load conditions such that tensile stress acts perpendicularly to the rolling direction of the material steel plate. Of the corners of the rectangular fitting hole formed by bending before welding, strong residual stress in the tensile direction due to welding often occurs in the corners near the welding part. If the bending process is performed easily, the curvature of the corner portion becomes extremely small, which further tends to cause stress concentration. A combination of these adverse conditions often led to cracking. On the other hand, the integrally molded product is often made of extremely soft steel or a steel similar to it in order to facilitate the molding process, so it is inherently quite soft. Therefore, the stress caused by the strong repeated torque of the claws is concentrated on the small area of contact, causing wear of the insertion hole and
It was easy to deform, and there were many problems such as the attached nail becoming loose and breaking.

[Purpose of the invention] This invention was devised in view of the above-mentioned problems. By improving the internal form of the claw holder, deformation and wear caused by the claw load can be suppressed, and the claw can be stably held for a long period of time. The purpose is to provide a holder.

[Structure of the invention] In order to achieve the above-mentioned object, this invention is provided with a nearly uniform section that protrudes from the outer periphery of the tilling shaft and supports a claw-side attachment part that has a substantially uniform cross section and has a predetermined width in the rotation direction. In the claw holder, the claw-side attachment part is fitted into the fitting part having a uniform closed cross-section form from the tip opening, and is attached to the claw by passing the fastener through a through-hole provided near the center of the side surface. Protrusions that abut and support the attachment parts on the front and rear claw sides are provided facing each other on at least the surface of the opening at the tip of the front and back sides of the rotation of the tilling shaft, and the dimensions between these protrusions are determined by the mounting state using the fastening tool. It is formed so as to closely match the width of the above-mentioned dimensions of the attachment part on the claw side.

[Example of idea] Examples of this invention will be described below.

The claw holder 3, which is welded and fixed to the outer periphery of the tilling shaft 1 so as to protrude in the radial direction, is an integrally molded product. A steel plate is deep drawn into a cylindrical shape with a bottom by cold forging, etc., a hole is made in the bottom, and this part is used as the tip 9 of the fitting part 7 that fits and supports the fitting part 5 shown by the chain line on the claw side. side.
The other end of the cylindrical body is welded to the outer periphery of the tilling shaft 1 as described above to form the claw holder 3. On the tip 9 side of the claw holder 3, a protrusion 11 is provided along the entire circumference on the outer circumferential side as shown in the figure. Then, protrusions 17a and 17b are provided on the inner periphery of the tip 9 side, that is, on the short sides 15a and 15b facing the front and rear sides in the rotational direction of the tilling shaft 1 among the four sides of the rectangle that is the flat closed cross section of the opening 13, It is raised one step higher than the other parts.
The surfaces of the protrusions 17a and 17b are precisely finished so as to closely match the contact surfaces of the attachment portion 5 on the claw side. Therefore, the dimension between the two protrusions 17a, 17b closely matches the width dimension of the mounting portion 5, and this state is achieved even when the claw is attached using a set bolt, which will be described later. As shown in the figure, the short sides 15a and 15b in a range other than the protrusions 17a and 17b are slightly enlarged to approximately uniform dimensions in the longitudinal direction of the claw, and are retracted rearward from the surfaces of the protrusions 17a and 17b. A through hole 19 for attaching a set bolt is provided near the center of the side surface of the claw holder 3.

Next, the operation of the above embodiment will be described.

Attach the attachment part 5 on the claw side to the claw holder 3 through the tip opening 13
Then, insert the set bolt into the through hole 19 and attach it with your nails. With the claw attached, the claw holder 3 has protrusions 17a and 17b finished in the fitting part 7 so as to accurately contact the mounting part 5 on the claw side.
By providing this, the claw can be held extremely strongly. In other words, as mentioned above, the insertion holes of conventional claw holders were difficult to finish, causing deformation and play due to stress concentration, but with the claw holder of this invention, the bending stress of the claws can be suppressed to the maximum. Finishing can be easily carried out because the area near the entrance of the fitting part, which is one of the receiving parts, has small-area protrusions 17a and 17b. As a result, the effective contact area with the claw side is significantly expanded, stress is dispersed, and local deformation is prevented. In other words, in the present invention, by finishing only the fitting portion protrusion of the claw holder, almost the entire surface of the protrusion becomes an effective contact surface.

The protrusion is located at the tip of the fitting part 7, and since it has a small area compared to the total internal area of the fitting part 7, it can be finished easily and with high precision in a short time. The tip of this fitting part 7 is of course an opening, and is originally the part with the most disadvantageous conditions in terms of strength, but the projections 17a, 1
It can be said that the fact that the wall thickness is increased by 7b to increase the rigidity, and that the stress is further dispersed by the finishing process is a very efficient measure for location. Further, in this embodiment, a protrusion 11 is also provided on the outer circumferential side of the fitting part 7, and the tip part of the fitting part 7 is made thicker to improve the rigidity, which is useful for preventing the deformation. .

It goes without saying that another location where the bending stress of the claws on the claw holder 3 acts maximum is at the inner part of the fitting portion 7. However, since this part is welded and fixed to the tilling shaft 1, the surrounding area has very high rigidity, which is much more advantageous than the tip 9 of the fitting part 7, and no special measures are usually required.

The projections 17a, 17b or the protrusion 11
The vicinity of the fitting part 7, that is, the vicinity of the tip of the fitting part 7, is usually formed by punching a hole in the bottom of a cylindrical body with a bottom formed by deep drawing with a press. Therefore, these protrusions or ridges undergo work hardening, albeit slightly.

Furthermore, since it is press-formed as described above, the tip 9
As shown in FIG.
a, 17b, and the vicinity of the protrusion 11 form a raised continuous flow. Both of these work hardening and continuous flow lines of the crystal structure work effectively to prevent wear and deformation of the claw holder 3.

As mentioned above, there is a protrusion 1 near the tip 9 of the claw holder 3.
7a, 17b, or even on the outer periphery of these parts to bring them into close contact with the attachment part 5 on the claw side.
17b and the vicinity of the bottom, that is, the vicinity of both ends, effectively and reliably hold the claw side, and the thickness of the intermediate portion can be made considerably thinner as long as the rigidity is not impaired. Therefore, each claw holder 3 can be made lighter, and the weight of the entire tilling shaft to which a large number of claw holders are attached can be significantly reduced. Furthermore, the claws that have been fitted into and attached to the claw holder 3 are affected by the above-mentioned strong torque, especially the claw holder 3.
The tip 9 is bent slightly. In response to this bending deformation of the claw, the tip 9 of the claw holder 3 is
If the corner portion 21 of is pre-processed into a small slope as shown in Fig. 6, when the claw is bent, the curved surfaces of both will match and the contact state of this portion will be changed from the conventional line contact to surface contact. This greatly reduces stress concentration. In addition, since the load from the claw attachment portion 5 is received by the protrusions 17a and 17b, the claw holder 3
The force acting on the tip 9 moves away from the tip 9, and stress concentration at the tip 9 is alleviated from this point as well, thereby preventing the occurrence of cracks at the tip 9. In this case, the stress concentration at the front end 9 can be alleviated by simply shifting the protrusions 17a and 17b to the inside of the fitting portion 7, in other words, to the lower side in FIG. can.

This can reduce the generation of linear traces that conventionally occurred on the claw side of this portion and the occurrence of R-shaped deformation (so-called sagging) of the tip 9 of the fitting portion 7 on the claw holder 3 side.

The claw holder of the present invention is not limited to the above embodiments, but can be modified in various ways. For example, the protrusion 17
The areas a and 17b are carburized to increase hardness. Or protrusions 17a, 17 in the length direction of the claw holder 3.
The contact area is expanded by increasing the width of b within a range that does not make finishing difficult. Furthermore, the tip 9 of the claw holder 3
Protrusions are provided along the entire circumference of the flat rectangular inner circumference to increase rigidity. By these measures, the period until the abutting portions on the claw holder 3 side and the claw side are deformed can be further extended than in the case of the previous embodiment.

[Effects of the invention] As is clear from the above, according to the structure of this invention, by providing a protrusion near the tip of the pawl fitting part of the pawl holder, finishing can be performed extremely easily and effective contact with the pawl side can be achieved. The area is increased and stress is greatly dispersed, which extremely effectively suppresses deformation and wear of the claw and claw holder due to the claw load, allowing the claw to be held stably for a very long period of time. Furthermore, the necessary range of finishing for the pawl fitting portion can be minimized, and the weight of the pawl holder can be greatly reduced. In the embodiment in which a protrusion is provided on the outer periphery of the tip of the claw holder, the strength of the tip of the claw holder is further improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a claw holder according to an embodiment of this invention, FIG. 2 is a plan view of FIG. 1, and FIG.
Fig. 4 is an enlarged configuration diagram showing the flow lines of a part of the internal tissue in Fig. 1, and Fig. 5 is an enlarged cross-sectional view of a part of Fig. 1, showing the claw and claw holder. 6 is a plan view showing the structure of a conventional claw holder, and FIG. 7 is a plan view showing another structure of the conventional claw holder. Explanation of main drawing symbols, 1... Cultivation axis, 3...
Claw holder, 5...attachment part (on the claw side), 7...fitting part, 9...tip, 11...projection, 13...opening, 17a, 17b...protrusion.

Claims (1)

[Claims for Utility Model Registration] (1) A substantially uniform closed cross-sectional form that protrudes from the outer periphery of the tiller shaft and supports a claw-side attachment portion that has a substantially uniform cross-section and has a predetermined width in the direction of rotation. In the claw holder, the claw side attachment part is fitted into the fitting part from the tip opening, and the claw is attached by passing the fixing tool through a through hole provided near the center of the side surface. Protrusions that abut and support the attachment part on the claw side are provided facing each other on at least the front and back sides of the rotation of the tilling shaft, and the dimensions between these protrusions are set so that the attachment part on the claw side remains attached with the fastening tool. A claw holder characterized in that the claw holder is formed to closely match the width of the mounting portion. (2) The claw holder according to claim 1, which is a registered utility model, characterized in that a protrusion is provided on the outer periphery of the distal end side of the claw holder.