EP0990088B1 - Nozzling device for chisel bits and a method for nozzling round shank chisel bits of a holing machine - Google Patents

Description

The invention relates to a spraying device for Chisel of a cutting device in which the chisel is used as a round shank chisel formed with a hard material or hard metal insert and the nozzles are oriented in the direction of the cutting track are, the water supply via a sector control over part of the revolution of the cutting heads or cutting rollers takes place, as well as on a method for spraying the picks a cutting device.

Chisel holders equipped with a spray device are, for example can be found in AT-B 375 149. Bedüsungseinrichtungen primarily serve for chisels of cutting heads the purpose of dust control and to avoid the risk of ignition of an emerging methane gas-air mixture. By cooling the chisel should naturally also reduce wear become. The previous training courses have primarily the safety aspects in the pit as the primary goal of the Striving for improvements. The one described in AT-B 375 149 Chisel holder is an axially displaceable in its receiving bore Shank of the chisel provided, the chisel one Valve arranged in the chisel holder for the supply of water actuated to the chisel or to the working face during the cut. Such from the chisel immediately when engaging in the Rock spraying leads to a substantial reduction of water consumption, with the problems of premature Chisel wear, especially with round shank chisels with a Hard material or carbide tip is not sufficient will be carried.

AT-B 389 738 is designed to reduce water requirements a chisel jetting and thus to reduce the risk of An intermittent softening of the sole in the area of the working face Loading the chisels of a cutting head with Coolant provided. The intermittent supply of pressurized water is here through a spool with slits perforations formed, which in the rotating Cutter head running channels are connected. Such one intermittent application of pressurized water to the nozzles in addition to reducing water consumption with a Sector control, such as in the DE 28 10 982 A1 is described. With such sector controls is over a predetermined center angle of rotation a cutting head the respective one in engagement Chisels fed pressurized water, the pressurized water in turn is applied via spray nozzles. The control element is included one connected to the pressurized water supply, only over a partial circumference extending control channel, which only over part of the rotation of a cutting roller the corresponding openings and thus the associated nozzles in Connection came. Such sector controls are common formed so that they over the central angular range Effect through which the chisels of the cutting roller or a cutting head is in engagement with the rock, this Central angle range is generally chosen to be less than 180 °, to reduce water consumption accordingly. For activation cooling was either the engagement of the chisel in the rock, or a control disc, which so was designed so that it only over a central angle of rotation of the cutting head or the cutting roller to effect through which the chisel engages with the rock stand.

The invention now aims at a cooling device or To create spraying device of the type mentioned with which not only ensures that the cutting track is sufficient is cooled to cause inflammation during methane outgassing avoid, but also the wear of picks with hard material or hard metal inserts essential can be reduced. To solve this problem there is Training according to the invention based on the above Spraying device essentially in that the axes of the Nozzles inclined to the chisel tip and in the cutting track and that the sector control is set to the nozzles over an angular range of at least 45 °, preferably 65 ° - 85 ° of the rotation of the cutting head or the cutting roller after the chisel emerges from the rock with pressurized water applied. The fact that now deviates from the known Facilities sector control is set so that the nozzles over an angular range of at least 45 ° Rotation of the cutting head or the cutting roller after the exit pressurized water from the rock, effective cooling of the chisel itself is now ensured, which can still be improved by the fact that Axes of the nozzles inclined to the chisel tip and into the cutting track are arranged. When using such round shank chisels with a hard material or hard metal insert has been shown that critical temperatures should not be exceeded because if this temperature is exceeded a particularly quick one Loss of strength especially in the case of hard metal inserts from tungsten carbides occurs. Such a critical temperature is usually not when a chisel emerges reached from a first cutting track. Through a kind of rocking the temperature at the entry of the chisel with higher Temperature in the subsequent cutting track can be the critical Temperature can easily be exceeded, causing it premature and rapid wear occurs. Now if the cooling is maintained over a partial area in which the chisel tips are at their highest temperature, succeeds with pressurized water due to the prevailing high Temperature difference a faster cooling to a lower Ensure temperature level, which when new entry of the chisel into the rock at the subsequent cutting track same chisel ensures that the critical temperature is not reached. While thus preventing the Risk of inflammation is definitely a smaller central angle Sector control can be described as sufficient, since yes the risk of ignition after the chisel emerges from the Cutting track is no longer available, it succeeds through the enlargement of the angular range by at least 45 ° after the exit the chisel, the critical temperature limits for wear of hard metal inserts or hard material inserts safe to avoid. Is essential in this context the combination of the orientation of the water jet at an angle Chisel tip back and forth in the cutting track with the measure that Continue cooling even outside of the tool, to watch.

The nozzles are advantageously used within the scope of the invention Spraying device designed as swirl nozzles. such Swirl nozzles increase the certainty that cooling water actually is brought up to the chisel tip and at the same time with Security also captures the hottest part of the cutting track.

The preferred angular range of approximately 65 ° -85 ° according to the invention outside the material intervention leads to a wake of the Cooling outside the procedure, with a significant reduction of water consumption through an intermittent spray can be achieved. The invention is advantageous The method is therefore carried out so that the nozzles are under one acute angle inclined to the axis of rotation of the picks and pressurized water with a pressure> 50 bar until the chisels are above a central angle of moved at least 45 °, preferably 65 ° - 85 ° out of the rock were, with preferably the water supply intermittent or pulsating. With such an intermittent Water consumption can be sprayed without significant Reduction of the cooling effect can be significantly reduced, whereby in that the cutting tool at the time of reaching its maximum temperature is cooled due to higher temperature difference to the temperature of the cooling medium maximum cooling effect is achieved. Cooling of the cutting tool is in the lower temperature range due to the lower Temperature differences are much less favorable and only significantly to achieve lower efficiency.

In principle, it is sufficient to align the cooling jet in this way make it at an acute angle to the chisel tip. A direct penetration of a cooling jet into the contact area the chisel tip to the rock is due to the high Contact pressure to the rock is not guaranteed. When exiting the chisel from the rock can be due to fluidic Effects the cooling water efficiently to the chisel tip and to continue to the hottest point.

Surprisingly, it has now been shown that the cooling effect and thus the influence on the wear of the hard metal or Hard material also to a large extent from the choice of Spraying water pressure is dependent. When falling below one Pressure of 60 bar and especially at pressures below 50 bar a significantly lower cooling effect was observed, with the Wear increased disproportionately. According to a preferred Further development of the method according to the invention is therefore so proceeded that the water pressure was chosen between 60 and 120 bar becomes. Comparative experiments have shown that an enlargement pressure above 120 bar no increase in cooling effect has resulted.

The wear of the hard metal or hard material inserts can be significantly reduced by keeping the peak temperature of the hard metal or hard material inserts of the round shank chisels below a critical temperature. The selected cutting speed also has a significant influence on the temperature level of the chisel tip. According to the invention, the procedure is therefore advantageously such that the cutting speed is reduced when the peak temperature approaches critical temperatures. The pronounced relationship between the tip temperature of the chisel and the cutting speed makes it seem particularly advantageous to lower the cutting speed compared to the conventional mode of operation. It is advantageously carried out in such a way that the cutting speed of the chisel is selected between 0.8 and 1.6 ms ^-1 .

Overall, the process of the invention minimizes Water use at the same time ensures that the desired one Cutting track nozzle eliminates the risk of ignition that a substantial dust precipitation is enabled, and cooling The chisel is made in such a way that critical temperatures cannot be achieved. If the chisels just outside of the procedure would be cooled quickly, wear and tear can be reduced. Because, however, none Cutting track spraying would be guaranteed, the use would be in methane outgassing rock not safe.

The invention is described schematically below with reference to the drawing explained in more detail. 1 shows a schematic Side view and Fig. 2 is an enlarged view of a Chisel holder for a round chisel for training after Fig. 1.

1 shows a partial cutting machine 1, which is movable on a crawler track 2 on the brine 3. The cutting machine has a 4 indicated schematically Loading device and a cutter arm 5, which around an essentially vertical axis 6 in the sense of the double arrow 7 is pivotable in the horizontal direction, and by one essentially horizontal axis 8 in the direction of the double arrow 9 is pivoted in the vertical direction. The Swivel drive in the vertical direction is shown schematically by a hydraulic cylinder piston unit 10 indicated. At the rear end the machine is indicated a discharge device.

The cutter arm 5 carries the cutter heads 11, which in the direction of Arrow 12 are driven in rotation. The schematically with 13 indicated chisel, which is designed as a round shank chisel and wear hard material inserts, dive into it Rock and exit at the end of their respective cutting track the rock. A sector control is now arranged and designed that the spraying of the chisel, as shown in Fig. 2 is explained in more detail, also about the central angle α of at least 45 ° and preferably 65 ° - 85 ° after the chisel emerges the face 14 is guaranteed. Overall, the Spraying, for example, extends over the central angle β, the spraying only after a first partial path of the chisel 13 in the face 14 is turned on. The area of intervention the chisel 13 in the face 14 is through the central angle γ illustrates which is usually a maximum of 180 ° is.

2, a round shank chisel 13 can be seen, which in a bit holder 15 about its axis 16 is rotatably fixed. The chisel shaft 17 is in one Bush 18 added to replace defective chisels facilitate.

In the chisel holder 15 nozzles 19 are arranged, which pressurized water is supplied via channels 20 from a sector controller. The Nozzles 19 have filter cartridges 21 in order to block the Prevent nozzles and are designed as swirl nozzles. The Nozzle axes 22 are at an acute angle to the axis of rotation 16 of the Picks 13 inclined towards the face 14, so that it is ensured that spray water, which the swirl nozzles leaves, actually in the cutting track and up to the top of the Chisel 23, which is designed as a hard material insert, arrives.

The chisels 13 in the training according to Figure 2 are in the sense of Arrow 12 moves into the working face, the angular ranges, via which the sector control ensure active spraying, are shown in Fig. 1.

The wear of the chisel tips 23 can be selected accordingly Cutting speeds in the range between 0.8 and Lower 1.6 m / s as much as by choosing an appropriate one Cooling water pressure between 60 and 120 bar.

Claims (9)

1. A nozzling device for the chisels (13) of a cutting machine in which the chisels are designed as round shank chisels (13) each including a hard-material or hard-metal insert and the nozzles (19) are oriented in the direction of the cutting trace, wherein the water supply is effected via a sector control over a portion of the revolution of the cutting heads (11) or cutting rolls, characterized in that the axes (22) of the nozzles (19) are arranged to be inclined towards the chisel tips (23) and into the cutting trace, and that the sector control is adjusted to feed the nozzles (19) with water under pressure over an angular portion of at least 45°, preferably 65° to 85°, of the revolution of the cutting head (11) or cutting roll, respectively, upon emergence of the chisels (13) from the rock.
2. A nozzling device according to claim 1; characterized in that the nozzles (19) are designed as swirl nozzles.
3. A method for nozzling the round shank chisels. (13) of a cutting machine according to claim 1, characterized by arranging the nozzles (19) in a manner inclined at an acute angle relative to the axes of rotation (16) of the round shank chisels (13) and feeding water under pressure to said nozzles at a pressure of more than 50 bar until the chisels (13) have been moved out of the rock over a central angle of at least 45°, preferably 65° to 85°.
4. A method according to claim 3, characterized in that said feeding of water is effected in an intermittent or pulsed manner.
5. A method according to claim 3 or 4, characterized in that the water pressure is selected between 60 and 120 bar.
6. A method according to any one of claims 3 to 5, characterized in that the top temperature of the hard-metal or hard-material insert of the round shank chisel (13) is kept lower than a critical temperature being a function of the hard metal.
7. A method according to claim 6, characterized in that the cutting speed is reduced as the top temperature approaches said critical temperature.
8. A method according to any one of claims 3 to 7, characterized in that the cutting speed of the chisels (13) is selected between 0.8 and 1.6 ms^-1.
9. A method according to any one of claims 3 to 8, characterized in that nozzling is started upon entry of the chisel (13) into the rock.

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