DE29621152U1 - Chisel to expose cables laid under mortar - Google Patents

Description

GRÜNECKER, KINKELDETF, SITOCKMAIR'&'SJSHWANHÄUSSER

LAW FIRM

LAW FIRM 'MAXIMILIANSTRASSE 58 D-80538 MUNICH GERMANY LAWYERS

DR. HERMANN SCHWANHÄUSSER
DR. HELMUT EICHMANN
GERHARD BARTH
DR. ULRICH BLUMENRÖDER, LLM.
CHRISTA NIKLAS-FALTER

PATENT ATTORNEYS

EUROPEAN PATENT ATTORNEYS

AUGUST GRÜNEECKER

DR. HERMANN KINKELDEY

DR. WILFRIED STOCKMAIR. AE. E.

DR. KLAUS SCHUMANN

PETER H. JAKOB

DR. GUNTER BEZOLD

WOLFHARD MEISTER

HANS HILGERS

DR. HENNING MEYER-PIATH

ANNE EHNOLD

THOMAS SCHUSTER

DR. WALTER IANGHOFF

DR. KLARA GOLDBACH

MARTIN AUFENANGER

GOTTFRIED KUTZSCH

DR. HEIKE VOGELSANG-WENKE

REINHARD KNAUER

DIETMAR KUHL

DR. FRANZ-JOSEF ZIMMER

BETTINA K. REICHELT

YOUR REF.

OUR REF.

G 3576-422/er DATE / DATE

05.12.96

Applicant: G + H Montage GmbH

Mayor-Grünzweig-Straße 67059 Ludwigshafen

Chisel for exposing cables laid under mortar

TEL 089/21 23 50 ■ FAX (GR 3) 089 / 22 02 87 · FAX (GR 4) 89 / 21 86 92 93 · E MAIL postmaster@grunecker.de ■ TELEX 529 380 MONA D
MAXIMILIANSTRASSE 58 · D-80538 MUNICH DEUTSCHE BANK MUNICH, NO. 17 51734, BLZ 700 700 10

Chisel for exposing cables laid under mortar

The invention relates to a chisel for exposing cables laid under mortar.

Cable harnesses installed under mortar, such as cable harnesses in wall or ceiling penetrations sealed with mortar, often have to be exposed for repair purposes or for re-laying cables, for which a chisel is used.

The present invention provides a chisel which is particularly suitable for exposing cables laid under mortar, which is characterized in that it has an electrically non-conductive material at least in its handle area.

This inventive solution avoids accidents caused by electric shock, which often occur when using conventional steel chisels. If the cables are damaged during chiseling and the cables have not been disconnected from the power supply, the chisel, which is provided with insulating material at least in the handle area, effectively protects its user from electric shock.

In a particularly advantageous embodiment of the invention, it is provided that essentially the entire chisel, including the cutting part, is made of electrically non-conductive material. This measure can prevent the chisel from creating a short-circuit connection between damaged cables, which can lead to the cable insulation burning or a cable fire due to arcing.

The electrically non-conductive material used is preferably a tough plastic, e.g. hard PVC or a tough

Polyamide. Plastics that can be cured using UV radiation, for example, can also be used advantageously.

In a special embodiment of the invention, the chisel has a material in the cutting and/or head area that is stronger than the material of its other parts. Such a higher material strength in the cutting and head area can be achieved, for example, by the above-mentioned hardening of a corresponding plastic material used to manufacture the chisel. On the other hand, however, a special cutting part, which consists, for example, of a resistant ceramic material or stone material, as well as a particularly resistant head part made of a metal that absorbs the blows on the chisel can also be provided, whereby conductive metal used only in the head area does not pose a particular risk with regard to possible electric shock accidents.

In a further particular embodiment of the invention, the chisel is designed as a plastic injection-molded part, whereby a cutting and/or head part made, for example, from the materials mentioned can be provided as a part embedded in the plastic during the manufacture of the chisel by plastic injection molding.

The invention will now be explained and described in more detail using embodiments and the accompanying drawings relating to these embodiments. They show:

Fig. 1 shows a chisel according to the invention, which is made exclusively from rigid PVC, and

Fig. 2 shows a chisel made of polyamide according to the invention with a cutting part made of ceramic and a metallic head part.

In Figure 1, whose sub-figures a) and b) show a chisel in side views rotated by 90° to each other, the reference number 1 designates a chisel cutting part which is formed by beveling a piece of round material on both sides. Accordingly, the chisel has a round-cylindrical section 2 extending over most of its length with a head face 4 serving as an impact surface.

The reference number 3 in Fig. 1 designates the cutting edge of the cutting part 1.

The chisel shown in Fig. 1, made in one piece from rigid PVC, can be used to expose cables laid under mortar, whereby the non-conductive PVC material protects the user of the chisel from electric shocks if cables are damaged during chiseling and the cables have not been de-energized before starting work.

Although the chisel made of plastic material shown in Fig. 1 is relatively soft compared to steel chisels, its strength is nevertheless sufficient to break open mortar coverings of cables and expose the cables. The cutting edge 3 of the chisel can be sharpened as required, as with any conventional chisel.

In the embodiment shown in Fig. 2, identical or identically functioning parts are designated with the same reference number, but with the letter a.

The chisel shown in Fig. 2 according to the partial figures a) and b) in two side views rotated by 90° to each other differs from the chisel according to Fig. 1 in that a separate cutting part 5 made of a ceramic or stone material and a separate head part 6 made of steel are provided. The cutting part 5 is provided with a widening projection 7 which projects into a round-cylindrical section 2a of the chisel, which consists of plastic. Similarly, the head part 6 has an extension 8 which projects into the plastic material of the round-cylindrical section 2a.

The cutting part 5 and the head part 6 are each embedded with their base or extension in the plastic material of the round-cylindrical part 2a, whereby this embedding was carried out during the injection molding of the round-cylindrical part 2a by arranging the parts 5 and 6 within the injection mold for embedding.

In the embodiment shown, the plastic material of the round-cylindrical section 2a is a tough, partially crystalline, very wear-resistant polyamide material, which is also resistant to many oils, greases, diesel, petrol, cleaners and the like. This material would also be suitable for producing a chisel made exclusively from it, as shown in Fig. 1. Such a polyamide material is commercially available, for example, under the name Tecamid 6.

The chisel shown in Fig. 2 is significantly more wear-resistant than the chisel in Fig. 1, both in the cutting edge and head area.

In contrast to the embodiments shown, chisels could only be supplied with a separate head or only with a

separate cutting part. If only one head part, e.g. made of metal, is used, the chisel would essentially wear down from the cutting part and would slowly wear out like a pencil through repeated regrinding of the cutting edge.

Claims (10)

Protection claims 1. Chisel for exposing cables laid under mortar, characterized in that the chisel has an electrically non-conductive material at least in its handle area (2). 2. Chisel according to claim 1, characterized in that the entire chisel including the cutting part is made essentially and in particular exclusively from an electrically non-conductive material. 3. Chisel according to claim 1 or 2, characterized in that the electrically non-conductive material is a plastic. 4. Chisel according to claim 3, characterized in that the plastic is hard PVC or a tough polyamide. 5. Chisel according to claim 3 or 4, characterized in that the plastic is a hardenable plastic. 6. Chisel according to one of claims 1 to 5, characterized in that the chisel has a harder material in the cutting edge and/or head area compared to the other parts of the chisel. 7. Chisel according to claim 6, characterized in that a cutting part (5) made of a ceramic or stone material is provided. 8. Chisel according to claim 6 or 7, characterized in that a head part (6) made of a metal is provided. 9. Chisel according to one of claims 1 to 9, characterized in that the chisel is manufactured by a plastic injection molding process. 10. Chisel according to claim 9, characterized in that a cutting part (5) and/or head part (6) is provided as a part embedded in plastic during manufacture of the chisel by the injection molding process.