JPH0121290B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides manual tools such as shovels and scoops,
More specifically, it relates to a hand tool consisting of a blade and a tubular handle.

Generally, in a hand tool, a blade is connected to a grip handle, and the tip end of the blade is inserted into a workpiece such as earth and sand, and a grip body provided at the rear of the grip handle is actuated to cover the workpiece with the blade. When working by lifting a workpiece, the heavier the workpiece near where the tip of the blade penetrates, the heavier the workpiece will be.
The distal end portion of the blade is firmly supported by the workpiece, and when the grip body is operated, a large bending stress is concentratedly applied to the connection position of the grip lever with the blade.

Therefore, conventionally, the blade mounting tubes are arranged at the end of the grip lever in abutting manner, and reinforcing bodies are inserted and reinforced on both sides of the butt part in the length direction, or the end of the grip rod is reinforced. The mounting tubes for the blades are arranged inside in a stacked manner, and a reinforcing body is inserted into the mounting tubes for reinforcement.

However, in either case, when the grip body is operated, the proximal portion of the grip lever that is continuous with the connection position with the blade comes into pressure contact with the proximal end of the reinforcing body or the blade mounting tube, causing bending stress. In the end, the above problem could not be fundamentally solved.

On the other hand, when the blade and the grip lever are connected, if the connection is made only by fitting the reinforcing rod, the degree of connection between the blade and the grip rod is weak, and the blade may come off from the grip rod after long-term use. From the fact that
Conventionally, the blade and the gripping rod are fixed by welding the joint between the blade and the gripping rod, or by passing a pin through the joint between the mounting tube, the gripping rod, and the reinforcing rod. However, these joining means require additional joining work such as welding or penetrating the pins in addition to the joining work by fitting the reinforcing rods. However, there was a problem that the joining process was extremely troublesome and time-consuming.

The present invention was invented in view of the above circumstances.
The objective is to enlarge the area near the tip of the tubular grip lever so that even if a small diameter tube is selected, the strength around the blade connection part against the bending moment of the grip rod can be sufficiently increased. At the same time, the weight can be reduced, and the blade and the grip can be easily connected by fitting the connecting piece of the blade into the handle lever and press-fitting a press-fit piece such as a wooden stopper into the connecting piece. The present invention is capable of quickly and easily connecting the gripping rod to the handle rod and reliably and firmly without the connecting piece coming off from the gripping rod.

Accordingly, in the configuration of the present invention, a large portion is provided near the tip of the gripping handle, and a substantially cylindrical connecting piece is provided that projects rearward from the rear end of the blade. Fitting into the tip of the gripping handle,
The blade is coupled to the handle lever, and extends diagonally upward from the rear end of the coupling piece toward the rear side;
Further, an extending portion is provided continuously along the inner surface of the raised portion of the enlarged portion, and a press-fitting piece is press-fitted into the connecting piece.

Embodiments of the manual tool of the present invention will be described below based on the drawings.

What is shown in the figure is a shovel, in which 1 is a hard metal blade that has been hardened, and has an approximately cylindrical connecting piece 10 that projects rearward from its rear end. The piece 10 is formed by bulge processing to provide an enlarged portion 20 near the tip of a soft, tubular metal handle rod 2 that has not been hardened, and the connecting piece 10 of the blade 1 is attached to the tip of the grip rod 2. The blade 1 is fitted into the grip lever 2 to connect the blade 1 to the grip lever 2, and a grip body 21 is fixed to the rear end of the grip lever 2.

Thus, the connecting piece 10 extends rearward and diagonally upward from the rear end, and the enlarged portion 20
An extending portion 20 is continuously provided along the inner surface of the raised portion a, and a press-fitting piece 3 is press-fitted into the connecting piece 10.

The enlarged portion 20 is located near the tip of the gripping rod 21, that is, from a position slightly closer to the blade 1 than the rear portion of the press-fit piece 3 where bending moment is applied during operation, over a certain distance toward the hand side. 20 is formed to have a circular cross-sectional outer shape and an equal diameter.

The metal tube used for the handle rod 2 has a smaller diameter, for example, 32 mm, than the normally used one, for example, 34 mm.
A diameter of 1.2 mm and a thickness of 1.2 mm are used, and the enlarged portion is expanded to a diameter of, for example, 35.2 mm, which has sufficient strength against the bending moment over the certain distance including the bending stress concentration position. It is.

That is, the thickness of the gripping rod 2 before the enlarged portion is t ₁ , the average diameter of the inner and outer diameters is d ₁ , and the enlarged portion 2 is
0 thickness is t ₂ (<t ₁ ), and the average diameter of the inner and outer diameter is d ₂ (>
d ₁ ), and assuming that the cross-sectional area of the gripping rod 2 does not change before and after the large-scale processing, πd ₁ t ₁
= πd ₂ t ₂ , therefore, the relationship d ₁ t ₁ =d ₂ t ₂ holds true.

By the way, the metal tube used for the gripping rod 2 has an outer diameter of 30 mm and a thickness of 1.2 mm, for example, so that the thickness value with respect to the average diameter is extremely smaller than 1. When the handle rod 2 is enlarged and its average diameter is increased by a certain percentage, for example 10%, the thickness will be reduced by approximately the same percentage as the certain percentage, for example 10%.

In addition, the section modulus of a tube with a circular cross section is π/32D (D ⁴ − d ⁴ ), where the outer diameter is D and the inner diameter is d. If the value of t is much smaller than 1, approximately
It becomes 0.8Da ² t.

Therefore, the section modulus of the handle rod 2 before and after the large-scale processing is approximately 0.8d ² ₁ t ₁ and 0.8d ² , respectively, since the value of the thickness with respect to the average diameter of the metal tube used is extremely smaller than 1. ₂ t ₂ , and therefore, the bending stress due to the bending moment M at each bending stress concentration position a for the handle rod 2 that has not been subjected to extensive processing and for the one that has been subjected to extensive processing is M/0.8d ² ₁ t _{1 .} , M/0.8d ² ₂ t ₂ .

Therefore, when the average diameter of the gripping rod 2 is increased by the certain percentage, for example, 10%, as described above, and the thickness is decreased by approximately the same percentage, for example, 10%, the bending stress applied to the bending stress concentration position a will decrease by approximately the same percentage as the above-mentioned constant percentage, for example, by 10%.

The connecting piece 10 is integrally press-molded at the same time as the blade 1 is manufactured, and has a cylindrical shape that tapers toward the rear end, and has an open portion 10a formed at its lower end. An extending portion 11 that faces rearward and extends obliquely upward is extended from approximately the upper half of the rear end, and when the connecting piece 10 and the grip lever 2 are connected, the outer surface of the extending portion 11 is extended. As shown in FIG. 2, it is located along the inner surface of the raised portion a where the stress is most concentrated in the bulged portion 20.

Reference numeral 12 denotes a stepped portion, which serves as a contact point between the blade 1 and the grip lever 2 when the coupling piece 10 is fitted onto the grip lever 2.

Further, as the press-fitting piece 3, a cylindrical wooden plug or a plastic member having a diameter slightly larger than the inner diameter of the coupling piece 10 is used, and a tapered part 31 is provided at the tip of the press-fitting side. Connecting piece 10
This is done to allow smooth press-fitting.

The press-fitting piece 3 may have a cylindrical shape as shown in the drawing, or may have a tapered shape.

The present invention is constructed as described above, and when the blade 1 and the gripping rod 2 are to be connected, the connecting piece 10 of the blade 1 is first fitted to the tip of the gripping rod 2. In this case, the tip of the blade 1 is inclined upward so that the inclined end 11a of the extending portion 11 comes into contact with the inner surface of the gripping handle 2, and in this state, the connecting piece 10 is fitted while being reduced in diameter. When this connecting piece 10 is fitted into the gripping rod 2, the connecting piece 10 expands in diameter within the gripping rod 2, and the outer surface of the extending portion 11 has the highest stress at the enlarged portion 20. The connecting piece 10 is located along the inner surface of the raised portion a where the ridges are concentrated, and prevents the connecting piece 10 from coming off from the gripping handle lever 2.

Next, the press-fitting piece 3 is press-fitted into the coupling piece 10, and the diameter of the coupling piece 10 is expanded by this press-fitting, and at the same time, the outer peripheral surface of the coupling piece 10 is pressed into engagement with the inner surface of the grip handle lever 2. , the extension part 11 is also enlarged in diameter and its outer surface is brought into pressure contact with the inner surface of the enlarged part a, so that the extension part 11 strengthens the raised part a where the stress is most concentrated, and at the same time Part 11
The connecting piece 1 is hooked onto the raised portion a of
This makes it possible to reliably prevent the grip rod 2 from being removed from the grip rod 2.

In the above-mentioned embodiments, the entire coupling piece 10 is approximately cylindrical, but as shown in FIGS. The open end edges 15a, 15a are connected to the connecting piece 10.
The protruding ends 15a, 15a may be made to protrude outward from the outer circumferential surface on the rear end side, interfere with the inner circumferential surface of the tip of the gripping handle 2, and deform outward into a raised shape.

With this configuration, when the coupling piece 10 is fitted to the grip handle lever 2, since the coupling piece 10 is harder than the grip handle lever 2, the rear end portion 15 of the coupling piece 10 is fitted outwardly from the outer peripheral surface of the rear end portion 15. The protruding edges 15a, 15a that protrude from the handle interfere with the inner circumferential surface of the tip of the grip lever 2, pushing the tip of the grip lever 2 outward as shown in FIG. The part b is pressed and deformed so that it becomes substantially straight on the open side of the protruding edges 15a, 15a, and the protruding edges 15a, 15a are bitten into the inner surface of the tip edge b part of the grip lever 2, while being press-fitted. By press-fitting the piece 3 into the connecting piece 10, the protruding edge 15a,
15a is pushed outward, and the substantially linear tip edge b of the handle lever 2 is pressed and deformed outward by the outer peripheral surface of the press-fit piece 3, as shown in FIG. As a result, the protruding edges 15a, 15a are bitten into the tip of the gripping rod 2, and the connecting piece 1
0 and the gripping handle 2, and at the same time, when the press-fitting piece 3 is press-fitted, the tip edge b of the gripping handle 2
As shown in FIG. 8, the connecting piece 10 of the press-fit piece 3 bites into the outer circumferential surface of the press-fit piece 3.
It is also possible to reliably prevent it from coming off.

Further, in the above-described embodiment, the enlarged portion 2
If the cross-sectional shape of the connecting piece 10 of the blade 0 and the blade 1 is made non-circular such as an ellipse, the section modulus becomes larger in the load direction side and the strength can be improved.Furthermore, as shown in FIG. 3 to 6 concave grooves c extending along the length direction on the outer periphery of 20...
By providing this, it is possible to increase the strength of the bulge 20 and at the same time prevent the hand from slipping when gripping the bulge 20. In this case, if the upper surface shape of the extending portion 11 is made to match the bottom surface of the groove c, the engagement between the upper surface of the extending portion 11 and the groove c will cause the connecting piece 10 to be connected to the grip handle. This is preferable because it provides a rotation prevention effect with the rod 2.

Furthermore, although the above embodiments are applied to a shovel, it goes without saying that the invention can also be applied to a shovel, an agricultural hawk, etc., although not shown.

As described above, the present invention provides an enlarged portion near the tip of the gripping handle, and also provides a substantially cylindrical connecting piece projecting rearward from the rear end of the blade. The connecting piece is connected to the gripping handle rod, and is connected to an extending portion extending diagonally upward from the rear end of the connecting piece toward the rear side and along the inner surface of the raised portion in the enlarged portion. Since the press-fit piece is press-fitted, by enlarging the vicinity of the tip of the tubular grip lever, even if a small-diameter grip rod is selected, the rear part of the press-fit piece is subject to bending moment during operation. It is possible to sufficiently increase the strength of the surrounding area and at the same time to reduce the weight.Moreover, as a means for connecting the blade and the handle lever, it is possible to fit the connecting piece of the blade to the handle lever, and to use the connecting piece. The blade and the handle rod can be quickly and easily connected by a simple connection operation by press-fitting the press-fit piece into the handle. The outer surface of the extending portion is located along the inner surface of the protruding portion where stress is most concentrated in the protruding portion, and the extending portion strengthens the protruding portion. It is possible to reliably prevent it from coming off.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and Fig. 1 is a plan view, Fig. 2 is a partially cutaway side view, Fig. 3 is a side view of the blade, Fig. 4 is a bottom view of the same, and Fig. 5 is a blade. 6 is a bottom view of the same blade, FIG. 7 is a sectional view along the same line, FIG. 8 is a partially cutaway side view of another embodiment, and FIG. 9 is a side view of the same blade. Partially cutaway side view showing the state in which the handle is fitted to the grip handle,
FIG. 10 is a sectional view taken along the line shown in FIG. 9, and FIG. 11 is a bottom view showing the state in which the press-fit piece is press-fitted into the joint piece.
FIG. 12 is a sectional view taken along the line XII-XII in FIG. 11. DESCRIPTION OF SYMBOLS 1...Blade, 10...Joining piece, 11...Extension part, 2...Grip handle lever, 20...Ampullament part, a...Protuberant part, 3...Press-fitting piece.

Claims (1)

[Claims] 1. A manual tool such as a shovel or a scoop consisting of a blade and a tubular gripping rod, wherein the gripping rod has an enlarged portion near the tip, and a portion protruding rearward from the rear end of the gripping rod. A cylindrical connecting piece is provided in a protruding manner, and the connecting piece is fitted into the tip of the gripping handle to connect the blade to the gripping handle, and the connecting piece is inserted from the rear end of the connecting piece toward the rear side. 1. A hand tool, characterized in that a press-fitting piece is press-fitted into the coupling piece, while an extension part extending obliquely upward and following the inner surface of the raised part of the enlarged part is provided in succession.