Method and Device for Monitoring Roller Drilling Tools

The invention relates to a method for monitoring the cutting or wart rollers, in particular of roadheading machines in mining and tunnel construction, by determining the loads occurring at the individual rollers. The invention also relates to a device for carrying out the method with measuring points which are equipped with strain gauges and an evaluating unit.

Part-face and full-face heading machines which are used in underground mining and tunnel construction and equipped with roller drilling tools comprise a drill head which works the entire face in the heading and detaches the solid mineral. This extraction work is done with the aid of cutting or wart rollers which are arranged at the rotating front disc of the drill head or the hood-shaped drill head. The cutting and wart rollers fragmentate the rock by high pressure and for this purpose the roadheading machine is braced against the sidewalls with prop claws or supported correspondingly on the floor. To determine the load distribution across the drill head region of these heading machines the loads occurring at the individual roller drilling tools are measured by means of strain gauges. These measurements at the bearing pedestals however do not provide full information because they do not permit any assessment of the rotational running condition of the roller drilling tools. The monitoring of the proper rotational condition of the roller drilling tools, which permits conclusions to be drawn on the wear behavior and on sparking possibly caused by stationary rollers, must therefore be carried out in parallel. For this purpose an additional measuring point is employed which by means of a so-called cam pulse indicates each revolution of the cutting roller. A disadvantage in the known method and also of the known device for carrying out the known method is that separate measurements must be made, that separate measuring points are necessary, and that roller rotation stoppage is possibly measured and reported only after a delay.

The problem underlying the invention is to make it possible to measure in combination and accurately the loading and the rotational behavior of the roller drilling tools of a heading machine or the like and to provide a device suitable for this purpose.

The problem underlying the invention is solved in that tangential expansions are measured at the races of rolling bearings supporting the roller drilling tools.

By the method according to the invention it is surprisingly possible for each roller drilling tool to simultaneously reliably monitor, by means of a single signal, both the load applied to and the rotational behavior of, the roller drilling tool. The appearance of the signal itself indicates that no stoppage of the rotation of the associated tool has occurred, while the absolute magnitude of the signal is an indication of the magnitude of the load applied to its tool. The values determined in this manner are substantially more accurate and simpler to transfer than those in the already known methods. As a result, a quicker and more reliable reaction to the operational behavior is possible. In regard to the device, the problem is solved in that the measuring point is arranged in one of the races of the measuring bearing and is formed as a strain gauge. This solution is advantageous because the arrangement is then of simple construction since only one measuring point need be provided and observed for each tool. It permits the monitoring of all the necessary functions and obtains the corresponding information.

The aimed for strain gauge measuring point introduced to a bearing makes it possible to determine reliably and simply, during a cutting operation, simultaneously, the necessary exact information on the magnitude of the loading of and on the rotational movement or standstill of the associated roller drilling tool. The characteristics of the measuring signal depend on the change of voltages due to the rolling of the bearing elements over the measuring point. Thus, an oscillatory measuring signal is produced from which it is possible to clearly read or conclude the rotational behavior of the roller drilling tool. It is particularly advantageous that the rotational behavior of the roller drilling tool is determined via a plurality of pulses per revolution. Standstill of a roller drilling tool can thus be detected within a short time and corresponding action taken.

An advantageously protected arrangement of the measuring point and at the same time a measuring signal providing an exact representation of the magnitude of the loading of the roller drilling tool and its rotational behavior is obtained or possible in that according to the invention the measuring point is associated with the edge of the outer and/or inner race opposite the bearing elements.

In a further advantageous embodiment the measuring point is located in a recess associated with the bearing element path. This provides reliable and exact detection of the loading of the roller drilling tools and of their rotational behavior.

It is particularly advantageous with the present invention that a substantial simplification of the measuring method is achieved and that a constructionally simple device which is easy to attach is provided in which, with the same measuring point, at the same time the magnitude of the loading of a roller drilling tool can be exactly determined as well as its rotational behavior. An essential advantage is further that during a cutting operation a plurality of pulses can be received and evaluated, thus providing a high information density.

Further details of the subject of the application will be explained in the follwing description of the Figures, wherein:

FIG. 1 is a front head view of a drill head of a full-face heading machine,

FIG. 2 is a cross-section through an antifriction or rolling bearing of a roller drilling tool with the measuring point in the outer race,

FIG. 3 is a longitudinal section corresponding to FIG. 2,

FIG. 4 is a cross-section of a rolling bearing with the measuring point in the inner race,

FIG. 5 is a longitudinal section corresponding to FIG. 4 and

FIG. 6 is a graphical representation of a measuring signal produced during rotation.

The drill head 1 illustrated in FIG. 1 is shown schematically and indicates substantially the arrangement of the various rollers 2, 3, 4, 5 via which the rock is cut and fragmentated by appropriate application pressure.

Each of the individual cutting rollers 2, 3, 4, 5 is equipped with a rolling bearing 6 as apparent from the fragment in FIGS. 2 to 5. Between the outer race 7 and inner race 9 a plurality of rolling bearing elements 8 is disposed which are intended to permit a uniform rotation of the cutting rollers 2 to 5. The outer race 7 may be the sleeve of the cutting roller and the inner race 9 the bearing axis of the cutting roller.

According to FIGS. 2 and 3, disposed in the outer race or ring 7 is a recess 10 which defines the measuring point 11, the measuring pickup of the measuring point 11 being a strain gauge 12 which is preferably adhered in the recess 10. According to FIGS. 4 and 5 this strain gauge 12 of the measuring point 11 is accommodated by a recess 10 of the inner race 9.

Both the construction according to FIGS. 2 and 3 and the construction according to FIGS. 4 and 5 have the recess 10 and the measuring point 11 associated with circumferential surface 15 of a bearing race while the rolling bearing elements 8 act directly on the other circumferential surface 14 of the same race. In each case the strain gauge 12 is connected to an evaluation unit 16.

FIG. 6 shows graphically the measuring signal produced during rotation of a cutting roller. It is distinguished by changes between extension regions 17 and stress regions 18, with the reference numeral 19 denoting the period between two successive maximum force introductions arising from a loading of the measuring point by the rolling bearing elements.