DE29600480U1 - Expansion head for drilling holes in the ground - Google Patents

Description

PATENT ATTORNEYS '. . : * III *

DiPL-iNG, CONRAD KÖCHLING *" -*- -

DlPL-ING. CONRAD-JOACHIM KÖCHLING Note: AVT Anti-Wear-Techni

P.O.Box2069, D-58020 Hagen GmbH.

FleyerStraße 135, D-58097 Hagen Heckenkamp 16

Call (02331) 811 64 + 85033

Fax (02331) 84840

Telegrams: Pateniköchling Hagen D — 58640 Iserlohn

Accounts: Commerzbank AG, Hagen 3515095 (bank code 45040042)

Sparkasse Hagen 100012043(BLZ45050001)

Postgiro: Dortmund 5989-460 (bank code 44010046) _________________

VNR: l.L..__ 51

Serial No. 1..2Q07/.96

12 January 1996

from the

CJK/HI.

Expansion head for creating holes in the ground

The invention relates to an expansion head for creating bores or channels in the ground, wherein the expansion head is equipped with a plurality of hard metal pins which are preferably arranged in a helical shape on the surface of the expansion head.

Such expansion heads are used to create holes or channels in the ground in which pipes or similar can be laid. To do this, a pilot hole of the appropriate length is first drilled. The pilot hole is then expanded by pulling the expansion head through the pilot hole.

In order to achieve the appropriate removal of soil in the borehole, the expansion head has a multiplicity of hard metal pins which are arranged in a helix shape,

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i.e. in the form of overlapping screw lines arranged on the outside of the expansion head.

To arrange the hard metal pins, it is currently necessary to drill holes in the casing of the expansion head into which the hard metal pins can be inserted. The hard metal pins are then soldered to the expansion head so that they protrude beyond its casing line.

The arrangement of the hard metal pins is extremely time-consuming and therefore associated with high costs.

Based on this prior art, the invention is based on the object of creating an expansion head of the generic type in which the arrangement of the hard metal pins can be carried out simply and quickly.

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To solve this problem, it is proposed that the hard metal pins are each held in a stud bolt made of weldable material, in particular steel, and that the stud bolt is welded directly or indirectly to the outer casing of the expansion head.

Because the hard metal pins are each held in a double stud made of weldable material, it is possible to weld the hard metal pins directly to the outer casing of the expansion head using the stud bolt. It is also possible to form a metal strip corresponding to the screw line of the stud bolts to be arranged, onto which the stud bolts are welded, whereby this metal strip is then welded to the expansion head. It is also possible to first weld the metal strip onto the expansion head and then weld the stud bolts onto this metal strip. The welding is preferably carried out by means of

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Lift ignition process. As a result of the design according to the invention, it is extremely easy and quick to fix corresponding hard metal pins to the expansion head by means of welding. Replacing worn hard metal pins is also easy in this way, since only the remains of the remaining stud bolt are cut off and then a new stud bolt with hard metal pin can be welded on.

It is preferably provided that the stud bolt is a cylindrical pot-like element which has an ignition tip on its base, preferably in the form of a ball, in particular made of aluminum.

Furthermore, it is preferably provided that the hard metal pin is designed as a cylindrical molded part and is pressed into the stud bolt.

Preferably, the hard metal pin is made of tungsten carbide.

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It is also preferred that the stud bolt is made of steel with a hardness of about 50 to 60 HRC.

An embodiment of the invention is shown in the drawing and described in more detail below. It shows:

Fig. 1 shows an expansion head in side view;

Fig. 2 a stud bolt with hard metal pin in side view, partially cut;

Fig. 3 shows a stud bolt with a hard metal pin welded to the expansion head in section.

In the drawing figure 1, an expansion head 1 is shown in a typical form. Such an expansion head is used to create holes or channels in the ground. The expansion head 1 is fitted with a large number of hard metal pins 2, which are arranged in parallel

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mutually extending screw lines are arranged over the length of the expansion head 1.

The carbide pins are, as can be seen in particular from Figure

2 and 3, each held in a stud bolt 3 made of easily weldable material, in particular steel. The stud bolt 3 is welded directly to the outer surface of the expansion head 1 in the embodiment. The stud bolt

3 is a cylindrical pot-like element which has an ignition tip h on its bottom, preferably in the form of a ball, in particular made of aluminum. The hard metal pin 2 is designed as a substantially cylindrical molded part and is inserted and pressed into the stud bolt 3 from its mouth. The hard metal pin 2 is preferably made of tungsten carbide. The

Stud bolt is preferably made of steel with a hardness of 50 to 60 HRC. As can be seen from a comparison of Figures 2 and 3, when the stud bolt 3 is welded to the casing of the

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Expansion head 1 covers a significant part of the base of the stud bolt, so that in the final state the hard metal pin 2 with its end facing the base of the stud bolt 3 almost rests against the outer surface of the expansion head 1. The arrangement according to the invention ensures a quick and secure fixation of the hard metal pins 2 to the outer surface of the expansion head 1.

The invention is not limited to the embodiment, but is variable in many ways within the scope of the disclosure.

All new individual and combination features disclosed in the description and/or drawing are considered essential to the invention.

Claims (5)

AVT 12007/96 Protection claims: 1. Expansion head for producing bores or channels in the ground, wherein the expansion head is provided with a plurality of hard metal pins which are preferably arranged in a helical shape on the surface of the expansion head, characterized in that the hard metal pins (2) are each held in a stud bolt (3) made of weldable material, in particular steel, and the stud bolt (3) is welded directly or indirectly to the outer casing of the expansion head (1). 2. Expansion head according to claim 1, characterized in that the stud bolt (3) is a cylindrical pot-like element which has an ignition tip (4) on its bottom, preferably in the form of a ball, in particular made of aluminum. AVT 12007/96 3. Expansion head according to claim 1 or 2, characterized in that the hard metal pin (2) is designed as a cylindrical molded part and is pressed into the stud bolt (3). 4. Expansion head according to one of claims 1 to 3, characterized in that the hard metal pin (2) consists of tungsten carbide. 5. Expansion head according to one of claims 1 to 4, characterized in that the stud bolt (3) consists of steel with a hardness of approximately 50 to 60 HRC.