JPH0549301A - Change pipe blade - Google Patents

Abstract

PURPOSE:To obtain a change pipe blade, having a blade part formed into a cylindrical shape, increasing the hardness of the inner peripheral surface of the blade part from that of the outer peripheral surface, capable of always maintaining the taper of the well-sharpened tip, stably usable for a long period without clogging the blade part with soil and useful as a tool, etc., for taking care of lawn. CONSTITUTION:In a change pipe blade of a tool, etc., for taking care of lawn, the change pipe blade body 1 is formed into a tapered cylindrical shape and a and carburized and hardened steel material is used as the material for the change pipe blade body 1. The tip of the change pipe blade body 1 is an entrance port 2 for soil and a tapered blade part (1a) is formed at its peripheral surface 5 so as to taper toward the tip. Thereby, the pipe blade body is readily driven into the lawn and its base end is a discharge port 3 for the soil entered from the tip. The tapered shape of the well-sharpened blade part (1a) is always kept by coating the outer peripheral surface 5 of the blade part (1a) with a carburizing preventive agent in producing the change pipe blade body 1, hardening and carburizing the blade part, preventing the carbon from permeating to the peripheral surface 5 of the blade part (1a) and lowering its hardness from that of the inner peripheral surface 4 of the blade part (1a).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a replacement pipe blade for lawn care tools and the like.

[0002]

2. Description of the Related Art In a conventional spare pipe, for example, as a spare pipe blade for a lawn care tool, as shown in FIG. The hardness of 12 was lower than that of the outer peripheral surface 13.
Then, attach a replacement pipe blade to the lawn care tool and drive it into the lawn to perform root cutting, or infiltrate the soil under the lawn from the tip of the replacement pipe blade and discharge it from the base end, and the discharged soil Was being exchanged for new soil.

[0003]

However, the conventional replacement pipe blade for lawn care tools has an inner peripheral surface 1 due to friction with soil.
2 was more worn than the outer peripheral surface 13. That is,
Since the cross section of the tapered blade portion 11 is worn away from the inner peripheral surface side rather than the outer peripheral surface, the tapered portion 11 is worn in the opposite tapered taper shape with respect to the replacement pipe blade main body and the worn portion 11
a is formed. Then, even if the pipe blade is driven into the lawn, the soil underneath will restrict the invasion of the soil by the wear portion 11a of the blade portion 11, and the soil will be less likely to enter the pipe. There was a problem that the soil could not be discharged as expected.

An object of the present invention is to provide a replacement pipe blade which can always maintain the tapered shape of the sharpened cutting edge.

[0005]

DISCLOSURE OF THE INVENTION The gist of the present invention is a replacement pipe blade having a cylindrical blade portion, in which the inner peripheral surface of the blade portion has a higher hardness than the outer peripheral surface. Is.

[0006]

With the above structure, wear is faster on the outer peripheral surface of the blade portion, but the inner peripheral surface of the blade portion wears slower than the outer peripheral surface, so that the tapered shape of the inner peripheral surface of the blade portion can be maintained. The soil does not clog the blade, and a stable use condition can be maintained for a long time.

[0007]

EXAMPLE An example in which the present invention is embodied in a lawn care tool will be described below with reference to FIGS.

As shown in FIG. 1, the spare pipe blade main body 1 is formed in a tapered cylindrical shape, and the material thereof is a JIS standard STKM type- # 11 carburized and quenched. The tip of the spare pipe blade main body 1 is an entrance 2 for dirt, and a tapered blade portion 1a is formed on the outer peripheral surface 5 of the tip so that the tip is tapered, and the pipe blade main body 1 is driven into lawn. Making it easier. The base end serves as a soil discharge port 3 that enters from the tip. This spare pipe blade body 1 is manufactured by coating the outer peripheral surface 5 of the blade portion 1a with an anti-carburizing agent, product name Anticarbon # 700 of Sanmizu Chemical Co., Ltd., and then carburizing and quenching the blade portion. The hardness is made lower than that of the inner peripheral surface 4 of the blade portion 1a so that carbon is less likely to permeate into the outer peripheral surface 5 of 1a.

Next, the operation of the replacement pipe blade for the lawn care implement thus constructed will be described. The replacement pipe blade body 1 is attached to a lawn care tool (not shown), and the replacement pipe blade body 1 is driven into the lawn to perform aged root cutting. or,
When exchanging the soil on the lawn, the replacement pipe blade main body 1 is driven into the lawn in the same manner as described above, the soil is caused to intrude through the intrusion port 2 and discharged from the discharge port 3.

When the above operation is repeated, as shown in FIG. 2, the inner peripheral surface of the blade portion 1a is worn away from the outer peripheral surface 5 having a hardness lower than that of the inner peripheral surface 4 due to the friction of soil, and has a hardness higher than that of the outer peripheral surface 5. No. 4 is hard to wear. Therefore, the soil that has entered through the entrance 2 is promptly discharged through the discharge port 3.

As described above, in the replacement pipe blade for lawn care implements of this embodiment, the hardness of the inner peripheral surface 4 is made higher than the hardness of the outer peripheral surface 5 so that the inner peripheral surface 4 of the blade portion 1a is resistant to abrasion. Since the property is improved, it is possible to quickly discharge the soil from the discharge port 3 without causing difficulty in discharging the soil.

The present invention is not limited to the above embodiment, and may be appropriately modified as shown below without departing from the present invention. (1) In the above embodiment, the material of the replacement pipe blade body 1 is JIS
Standard STKM system- # 11 was used, but JIS standard S15CK system, SPC system or STKM system- # 9 to 15
Any of these materials may be used.

(2) In addition to lawn care tools, the present invention can be applied to, for example, a punch for eyelets of cloth or a punch for punching leather. (3) Although the carburizing inhibitors of Sansui Chemical Co., Ltd. were used in the above examples, carburizing inhibitors of other manufacturers may also be used.

(4) In the above embodiment, the carburizing inhibitor is used as the blade portion 1.
Although carbon is applied to the outer peripheral surface of a to make it difficult for carbon to permeate, copper may be plated instead of the carburizing inhibitor to prevent carbon from permeating.

[0015]

As described in detail above, according to the replacement pipe blade of the present invention, the excellent effect that the tapered shape of the sharpened cutting edge can always be maintained is exhibited.

[Brief description of drawings]

FIG. 1 is a partial front cross-sectional view of a replacement pipe blade body in the present embodiment.

FIG. 2 is a sectional view of the same main part.

FIG. 3 is a sectional view of a main part of a conventional replacement pipe blade body.

[Explanation of symbols]

 1a blade portion, 4 inner peripheral surface, 5 outer peripheral surface

Claims (1)

[Claims] 1. A replacement pipe blade having a cylindrical blade portion, wherein an inner peripheral surface of the blade portion has a hardness higher than that of an outer peripheral surface thereof.