JPH051212Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention is an improvement of a pawl holder that protrudes from the tilling shaft of a tiller in order to attach the pawl to the tilling shaft of a tiller, especially a pawl holder that is provided with an insertion hole. It is related to.

[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 rectangular cross section, two steel plates bent into a U-shape are welded together as shown in Fig. 5, and one is integrally formed as shown in Fig. 6. be. This pawl holder is radially welded and fixed to the tilling shaft, and the pawl-side attachment part is fitted into the insertion hole of the pawl holder and fixed with a set bolt to attach the pawl to the tilling shaft and perform tilling work.

However, when the pawl's extremely strong and highly fluctuating torque is repeatedly applied to the pawl holder with the insertion hole formed as described above, the actual contact surface between the pawl and the pawl holder is originally small, and stress is generated. In a state where it is easy to concentrate, the above-mentioned weld-formed products tend to crack under loads where tensile stress acts perpendicular to the rolling direction of the material steel plate, especially under the above-mentioned concentrated loads. The corners of a rectangular insertion hole that are close to the welding area often generate strong residual stress in the tensile direction due to welding.
In addition, if the bending process is performed easily, the corner surface curvature becomes extremely small, which tends to cause stress concentration, and these factors often overlap to cause cracks.

On the other hand, in the case of the integrally molded product, very mild steel or a steel similar to it is often used to facilitate the forming process, so it is inherently too soft and the high cyclic torque of the claw is Stress concentrates on a small area of contact, causing wear of the insertion hole,
It was easy to deform, and there were many problems in which the attached nail would become loose, leading to nail breakage.

[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. It provides a holder.

[Structure of the invention] In order to achieve the above object, this invention has the above-mentioned fitting part protruding from the outer periphery of the tilling shaft and supporting the claw-side attachment part having a predetermined width in the rotation direction. In a claw holder in which the claw-side mounting portion is fitted and attached with a fastening tool for claw mounting, the claw-side mounting portion is brought into contact with the claw-side mounting portion at a plurality of locations in the depth direction at least at both ends of the claw holder in the width direction. Supporting protrusions are provided to face each other, and the dimension between these protrusions is formed to match the width of the dimension of the attachment part on the claw side.

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

FIG. 1 is a longitudinal sectional view of the claw holder of this invention attached to a tiller shaft, and FIG. 2 is a plan view thereof.

The claw holder 3 fixed to the outer periphery of the tilling shaft 1 by welding in the radial direction is an integrally molded product, and includes a fitting part 7 with a rectangular cross section that surrounds a mounting part 5 of the claw shown by a chain line (not shown). ing. Near both ends of the fitting part 7 in the depth direction, that is, near the entrance and near the bottom, protrusions 9a and 9b annularly protrude further toward the center of the fitting part 7 than other parts and have a rectangular cross section.
is provided. These protrusions 9a and 9b are accurately finished in shape and size so as to surround the claw-side attachment portion 5 and contact its outer periphery. Therefore, the area other than these protrusions 9a, 9b is slightly enlarged to have a rectangular cross section as shown in the figure, and forms a hole 11 recessed rearward from the inner peripheral surface of the protrusions 9a, 9b.
A set bolt insertion hole 13 is provided near the center of the side surface of the claw holder 3.

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

This claw holder 3 is provided with protrusions 9a and 9b in the fitting part 7, which are finished so as to accurately contact the mounting part 5 on the claw side, so that the claw can be held extremely strongly. In other words, in the conventional claw holder 3, the dimensional accuracy of the insertion hole is extremely poor due to the fact that it is manufactured using the above-mentioned molding method and the difficulty of accurately finishing the entire surface of the flat rectangular insertion hole. As such, stress tends to be concentrated due to local contact with the nail.

On the other hand, with the claw holder 3 of the present invention, it is only necessary to accurately finish the protrusions 9a and 9b at both ends of the fitting part 7, so the finishing position is good, and the machining area is small, so accuracy can be achieved in a short time. Can be processed well, with protrusions 9
Almost the entire area of a and 9b becomes an effective contact surface. This makes it possible to avoid the phenomenon of stress concentration caused by claw torque, and prevents damage, wear, and deformation that would occur in the past. In addition, the protrusions 9a and 9b are usually formed by
This is done by pressing the material, which is once formed into a straight cylindrical body, in the length direction using a core and a press die. As a result, the inner diameter side surfaces of the protrusions 9a and 9b undergo work hardening, albeit slightly. Furthermore, since it is press-formed as described above, the protrusions 9a and 9b are
The flow lines of the crystal structure inside the claw holder 3 form a raised continuous flow along the length direction of the claw holder 3 at the protrusions 9a and 9b, both of which work effectively to prevent wear and deformation of the claw holder 3. do.

In addition, the configuration in which the protrusions 9a and 9b are provided and brought into contact with the claw-side mounting portion 5 has the effect of extremely effectively increasing the rigidity of the claw holder without increasing the overall weight of the claw holder 3. .

Next, as shown in FIG. 3 as a longitudinal cross-sectional view similar to FIG. An annular protrusion 15 is also provided on the outer peripheral tip of this claw holder 3.
By providing this, the claw supporting rigidity of the claw holder 3 can be further improved.

Further, as shown in a plan view in FIG. 4 as another embodiment, the present invention can also be applied to a claw holder 3 having a U-shaped cross section so as to abut and support the mounting portion 5 on the claw side from three directions. By applying the projections 9 near both ends in the depth direction of the fitting part 7 of the claw holder 3, the same function as described above can be exerted, and stable and strong claw retention can be continued for a long period of time.

[Effects of the invention] As is clear from the above, according to the configuration of this invention, by providing the protrusions near both ends of the pawl fitting portion of the pawl holder, deformation and wear of the pawl holder due to the pawl load are extremely effectively reduced. The nail can be held stably for a very long time. However, the weight of the claw holder is rather reduced.

In an embodiment in which a protrusion is provided on the outer periphery of the distal end of the claw holder, the strength of the distal end of the claw holder is further improved.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a claw holder according to an embodiment of this invention, Fig. 2 is a plan view thereof, Fig. 3 is a longitudinal sectional view of a claw holder of another embodiment, and Fig. 4 is a further embodiment. FIG. 5 is a plan view of a conventional welded pawl holder, and FIG. 6 is a plan view of a conventional integrally molded pawl holder. Explanation of main drawing symbols, 1... Cultivation axis, 3...
Claw holder, 5... (claw side) attachment part, 7... Fitting part, 9... Protrusion part, 15... Outer peripheral protrusion part.

Claims (1)

[Claims for Utility Model Registration] (1) A fitting part on the claw side that is protruding from the outer periphery of the tilling shaft and has a width of a predetermined dimension in the direction of rotation, and that supports the fitting part on the claw side. In a claw holder that is fitted with a fastener and attached with a fastening tool, the claw holder is provided at least at both ends in the width direction at a plurality of locations in the depth direction, protrusions that abut and support the mounting portion on the claw side. A claw holder characterized in that the two projecting stripes are provided facing each other, and the dimension between these protrusions is formed to match the width of the dimension of the attachment portion on the claw side. (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.