GB2055928A

GB2055928A - Cutting tool system

Info

Publication number: GB2055928A
Application number: GB8025209A
Authority: GB
Original assignee: Fried Krupp AG
Current assignee: Fried Krupp AG
Priority date: 1979-08-04
Filing date: 1980-08-01
Publication date: 1981-03-11
Also published as: DE2931785A1; FR2463232A1

Abstract

A tool for cutting rock or minerals includes a chisel 1 rotatably mounted in a holder 2. An annular disc 5 of wear-resistant material is disposed between the chisel and the holder and its external diameter exceeds the maximum diameter of the chisel. The disc rests on the end face of the holder or is accommodated in a recess in the holder. <IMAGE>

Description

SPECIFICATION Cutting tool system The invention relates to a tool system for cutting rock and minerals, such for example as coal, ore or salt, comprising a rotary chisel, a chisel holder and a wear-resistant disc. Cutting tool of this kind, in particular cutting chisels, rotate automatically in use so that there is a selfsharpening effect.

In existing tools the rotary chisel is generally mounted directly in a chisel holder, which results in the rotating chisel imposing severe wear on the holder. Replacement of a chisel holder welded to a roller involves high costs and regular intermission of operation. If the necessary welding cannot be performed on site, for example due to the explosive atmosphere in a coal mine, the complete cutting roller must be taken away for repair in a workshop.

Some improvement is provided by tools having an inserted hard wear-resistant sleeve. It has also been proposed to apply by welding wear-resistant alloys to the surfaces of the chisel holder which are subjected to wear.

While both these types of tool have a higher wear-resistance they have the disadvantage of much high manufacturing cost. Another tool system has been proposed with a view to reducing the wear of the tool holder which consists of a sleeve rotatably mounted in a chisel holder and a chisel which is rotatably mounted in the sleeve.

Tool systems of this kind can only be used up to a certain limited size. In propelled machines, for example, which require large cutting chisels this construction cannot be used because the holder must be made so large that the required cutting line spacing between the cutting chisels cannot be maintained. In addition such tool systems are very expensive.

The object of the invention is to provide a tool system for cutting rock and minerals which exhibit a minimum wear of the chisel holder and does not involve high production costs.

This object is achieved by a tool system as described in claim 1. This tool system includes a wear-resistant disc, the diameter of which exceeds the maximum diameter of the chisel. This tool system is not significantly more expensive to manufacture than those hitherto known but has a substantially greater contact surface between the wear-resistant disc and the chisel holder which results in a considerable reduction in the wear of the chisel holder. The use of the wear-resistant disc yields the advantage that the diameter of the chisel can be small, so avoiding use of a large amount of steel for the chisel and performance by the chisel of much cutting work.The main advantage of the tool system according to the invention is that the major amount of wear no longer occurs as in the past on the chisel holder but on the contact zone between the wearresisting disc and the cutting chisel as it is here that the considerably smaller contact surface is located.

According to a further feature of the invention, the wear-resistant disc is accommodated in a recess in the holder or rests loosely on the holder.

This enables the wear-resistant disc to be easily and rapidly exchanged after use.

Embodiments of the invention are shown in the drawings, in which: Fig. 1 is a side view of a chisel, and Figs. 2 and 3 are longitudinal sections of alternative tool systems.

The chisel 1 shown in Fig. 1 has a collar 3 and an adjoining abutment surface 4.

Fig. 2 shows the chisel of Fig. 1 mounted in a chisel holder 2. Between the collar 3 on the chisel 1 and the holder 2 is a wear-resistant disc 5 of thickness b. The diameter dofthe disc 5, which rests loosely on the holder 2, is related to the diameter D of the collar 3 in the ratio 5 :4. This ensures that the abutment surface against the holder 2 is considerably greater than previously and the larger contact surface between the disc 5 and the holder 2 considerably reduces the wear on the holder 2.

The embodiment of the invention shown in Fig.

3 includes a chisel 1 mounted in a holder 2 which corresponds to that shown in Fig. 2 and a wearresistant disc 5 of diameter d disposed between the chisel and the holder. In contrast to the embodiment of Fig. 2, the disc 5 is accommodated in a recess 6 in the holder 2.

1. A tool system for cutting rock and minerals, such for example as coal, ore or salt, comprising a rotary chisel, a chisel holder and a wear-resistant disc, characterized in that the diameter of the wear-resistant disc exceeds the maximum diameter of the chisel.

2. A tool system according to claim 1, characterized in that the disc rests loosely on the holder.

3. A tool system according to claim 1, characterized in that the disc is accommodated in a recess in the holder.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Cutting tool system The invention relates to a tool system for cutting rock and minerals, such for example as coal, ore or salt, comprising a rotary chisel, a chisel holder and a wear-resistant disc. Cutting tool of this kind, in particular cutting chisels, rotate automatically in use so that there is a selfsharpening effect.

In existing tools the rotary chisel is generally mounted directly in a chisel holder, which results in the rotating chisel imposing severe wear on the holder. Replacement of a chisel holder welded to a roller involves high costs and regular intermission of operation. If the necessary welding cannot be performed on site, for example due to the explosive atmosphere in a coal mine, the complete cutting roller must be taken away for repair in a workshop.

Some improvement is provided by tools having an inserted hard wear-resistant sleeve. It has also been proposed to apply by welding wear-resistant alloys to the surfaces of the chisel holder which are subjected to wear.

While both these types of tool have a higher wear-resistance they have the disadvantage of much high manufacturing cost. Another tool system has been proposed with a view to reducing the wear of the tool holder which consists of a sleeve rotatably mounted in a chisel holder and a chisel which is rotatably mounted in the sleeve.

Tool systems of this kind can only be used up to a certain limited size. In propelled machines, for example, which require large cutting chisels this construction cannot be used because the holder must be made so large that the required cutting line spacing between the cutting chisels cannot be maintained. In addition such tool systems are very expensive.

The object of the invention is to provide a tool system for cutting rock and minerals which exhibit a minimum wear of the chisel holder and does not involve high production costs.

This object is achieved by a tool system as described in claim 1. This tool system includes a wear-resistant disc, the diameter of which exceeds the maximum diameter of the chisel. This tool system is not significantly more expensive to manufacture than those hitherto known but has a substantially greater contact surface between the wear-resistant disc and the chisel holder which results in a considerable reduction in the wear of the chisel holder. The use of the wear-resistant disc yields the advantage that the diameter of the chisel can be small, so avoiding use of a large amount of steel for the chisel and performance by the chisel of much cutting work.The main advantage of the tool system according to the invention is that the major amount of wear no longer occurs as in the past on the chisel holder but on the contact zone between the wearresisting disc and the cutting chisel as it is here that the considerably smaller contact surface is located.

According to a further feature of the invention, the wear-resistant disc is accommodated in a recess in the holder or rests loosely on the holder.

This enables the wear-resistant disc to be easily and rapidly exchanged after use.

Embodiments of the invention are shown in the drawings, in which: Fig. 1 is a side view of a chisel, and Figs.
2 and 3 are longitudinal sections of alternative tool systems.

The chisel 1 shown in Fig. 1 has a collar 3 and an adjoining abutment surface 4.

Fig. 2 shows the chisel of Fig. 1 mounted in a chisel holder 2. Between the collar 3 on the chisel 1 and the holder 2 is a wear-resistant disc 5 of thickness b. The diameter dofthe disc 5, which rests loosely on the holder 2, is related to the diameter D of the collar 3 in the ratio 5 :4. This ensures that the abutment surface against the holder 2 is considerably greater than previously and the larger contact surface between the disc 5 and the holder 2 considerably reduces the wear on the holder 2.

The embodiment of the invention shown in Fig.
3. A tool system according to claim 1, characterized in that the disc is accommodated in a recess in the holder.

3 includes a chisel 1 mounted in a holder 2 which corresponds to that shown in Fig. 2 and a wearresistant disc 5 of diameter d disposed between the chisel and the holder. In contrast to the embodiment of Fig. 2, the disc 5 is accommodated in a recess 6 in the holder 2.

1. A tool system for cutting rock and minerals, such for example as coal, ore or salt, comprising a rotary chisel, a chisel holder and a wear-resistant disc, characterized in that the diameter of the wear-resistant disc exceeds the maximum diameter of the chisel.

2. A tool system according to claim 1, characterized in that the disc rests loosely on the holder.