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CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims benefit of German Patent Application No. DE 10 2017 130 800.8, which was filed Dec. 20, 2017, and which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to a tool for installing a bit on and/or deinstalling a bit from a bit holder system of a milling machine, in particular a road milling machine, having at least one initiator with which installation and/or deinstallation of a bit is initiated.

The invention also relates to a bit holder system for a milling machine, in particular a road milling machine, having at least one bit receptacle for detachable fastening of at least one bit on a milling drum of the milling machine.

The invention also relates to a method for monitoring the wear of bits and/or of replaceable bit holders on bit holder systems of a milling drum of a milling machine, in particular a road milling machine, for replacement of the bits the bits being deinstalled from the bit holder systems with the aid of a tool, and/or the bits being installed on the bit holder systems with the aid of the tool, and the wear behavior of the bits and/or of the replaceable bit holders being determined on the basis of the number of bits replaced and/or the number of replaceable bit holders replaced.

BACKGROUND

Earth working machines that mill away the ground are used to remove earth material, for example for road repair or for surface mining. The earth working machines each have for that purpose a rotating milling drum on whose surface bits are arranged. The bits, constituting consumable parts, are replaceably connected to a milling drum tube of the milling drum. It is known for this purpose to fasten bit holder systems, by which the bits are detachably held, on the milling drum tube. The bit holder systems each comprise a bit holder for reception of the bits. Said holders can be directly connected to the milling drum tube, for example welded thereonto. It is also known to fasten a respective base mount onto the milling tube and to hold the bit holders detachably thereon. In a bit holder system of this kind comprising a base mount and a bit holder, a worn-out bit can be taken out of the bit holder and a worn-out bit holder can be removed from the base mount and substituted.

Separate tools for taking the bits out of the bit holders are known. One such tool is described in DE 10 2008 025 071 A1. A positioning member of the tool which carries a drift punch at its free end is held displaceably on a base part of the tool. The positioning member is coupled indirectly or directly to a piston-cylinder system or to an electric-motor unit which, after actuation of an initiator, pushes the terminal end of the drift punch against a support surface that constitutes the end-located termination of a bit shank held in the bit receptacle of the bit holder. The bit can be embodied as a round-shank bit, the bit shank being held in the bit receptacle, by means of a clamping sleeve, rotatably around its longitudinal axis but in axially immobilized fashion. The bit is pushed out of the bit holder by the pressure of the drift punch on the end of the bit shank. For that purpose, the tool is buttressed with its base part against the bit holder or against a wear protection washer arranged between a bit head and a projection of the bit holder.

DE 10 2007 030 640 B3 discloses a tool for installing and deinstalling a bit on a bit holder. The tool comprises a positioning member that can be displaced in two opposite directions by means of a positioning unit that is bidirectionally power-actuatable. A push-off portion, and a pull-in portion spaced away therefrom, are associated with the positioning member. The positioning member can be placed in an indentation on a base part of a bit holder by which a bit holder is held. It is also possible for the base part and the bit holder to be combined in one piece as a physical unit. In a pushing-out direction, the positioning member abuts with the push-off portion against a cylindrical supporting part that forms the termination, facing away from the bit head, of a bit shank of a round-shank bit. The pull-in portion encompasses the cylindrical supporting part and engages into a groove constituted between the cylindrical supporting part and the bit shank. A force in an ejection direction can thus be transferred to the bit by means of the push-off portion, while a force in a drawing-in direction of the bit can be introduced by engagement of the pulling-in portion into the groove. The positioning unit is hydraulically driven, and is coupled for that purpose to a battery-driven hydraulic unit. The positioning unit and the positioning member connected to it can be displaced by corresponding application of control, and a bit can thereby be ejected or drawn into the bit receptacle of the bit holder.

The document US 2015/0300165 A1 discloses a milling drum whose detachably fastened milling tools (bits) are each fitted with a transponder (RFID). The transponders contain data that enable unique identification of the respective milling tools. Associated with the milling machine is a reading device that reads out the information stored in the transponders and forwards it to a computer, which compares the received data with data stored in a memory. If the data are discrepant, it is assumed that a respective milling tool has been lost. A milling machine can thus determine, at any time, the number of milling tools present.

US 2017/0011564 A1 describes a monitoring system for bits of a milling drum. At least one transmitter, for example in the form of an RFID transmitter, is associated with each bit. The transmitter is in radio communication with a receiver arranged on the milling machine, and via that receiver with an evaluation system. If a signal of a transmitter is absent, the evaluation system recognizes the loss of, or impermissible wear on, a bit. For wear recognition, the at least one transmitter is arranged inside the bit or bit head. As wear on the bit advances, the transmitter becomes exposed and is destroyed.

DE 10 2016 113 251 A1 discloses a milling machine, a milling drum for such a milling machine, and a method for operating the milling machine. A means for determining a characteristic feature of the milling drum is associated with the milling machine. A value to be set, and/or a setting range, for at least one machine parameter of the milling machine is predefined on the basis of that characteristic feature. For example, the type of milling drum and thus the milling task can be determined on the basis of the characteristic feature. A characteristic feature can be defined, for example, by an identifier of the milling machine. Such an identifier can be stored in an active or passive transponder. The identifier or the transponder can be arranged in or on a milling drum tube, a tool holder, or a milling tool.

BRIEF SUMMARY

The object of the invention is to create a tool, for installing and/or deinstalling a bit on a bit holder of a bit holder system of a milling drum, which provides a user with improved information for ascertaining wear.

A further object of the invention is to furnish a corresponding bit holder system.

Another object of the invention is to furnish a method with which the wear behavior of bits and bit holders of a milling machine can be easily and reliably ascertained.

That object of the invention which relates to the tool is achieved by the fact that the tool comprises a detection device having at least one counting device; and that the detection device is designed to detect a number of bits deinstalled using the tool and/or a number of bits installed using the tool. The machine operator and/or the persons maintaining the milling machine thus know directly how many bits on a milling drum have been changed. Errors in determining the number of bits replaced, which can occur with simple counting by maintenance personnel, are thereby reliably avoided. Based on the number of bits deinstalled and/or installed, the machine operator can draw conclusions as to the wear behavior of the bits in the context of the milling task that has been carried out. This makes possible a prognosis regarding future wear behavior as the milling task is continued. From that prognosis it is possible to infer, for example, the bits required until the milling task is completed, or a suitable duration for the maintenance intervals. The numbers regarding replaced bits can be used to manage the spare parts inventory and the bits supplied to a construction site and kept in stock at the site. Based on the bit changes required, conclusions can be drawn as to the material properties of the substrate being milled. The machine parameters can then, for example, be adapted in such a way that the greatest possible milling output, simultaneously with minimum wear, is achieved. This allows the milling machine to be operated economically. In consideration of the detected number of exchanged bits, the machine utilization efficiency, and costs for machine utilization for a completed milling job, can be determined. Advantageously, the detection device is arranged on the tool with which the bits are inserted and removed. This is advantageous as compared with known detection devices arranged on the milling machine in the immediate vicinity of the milling drum, since the detection device is not exposed to the large mechanical stresses that occur during the milling process. The bits are held by bit holder systems that are mounted on a milling drum tube of the milling machine. A respective bit holder system comprises for that purpose a corresponding bit holder that encompasses, for example, a bit receptacle for receiving and detachably securing a bit shank. The tool is embodied to introduce the bit with its bit shank into the bit receptacle of the bit holder and/or to drive it out thereof. The bit holder can be secured directly on the milling drum tube. It then constitutes the bit holder system. Provision can also be made that a replaceable bit holder is held detachably by a base carrier, the base carrier being connected fixedly to the milling drum tube, for example via a welded join. The bit holder system is then constituted by the replaceable bit holder and the base carrier.

Simple and reliable detection of the inserted and/or removed bit can be accomplished by the fact that the detection device is configured, upon actuation of the at least one initiator, to increment by one a count status of the counting device for the number of deinstalled bits or for the number of installed bits. Actuation of the initiator represents a unique signal that is easy to detect and can be uniquely associated with an inserted and/or removed bit.

In accordance with a preferred variant embodiment of the invention, provision can be made that the detection device is embodied, upon actuation of the at least one initiator, to read out at least one identifier arranged on the bit holder system onto which the tool is placed; and/or that the detection device is embodied, upon actuation of the at least one initiator, to read out at least one identifier that is arranged on the bit held by the bit holder system onto which the tool is placed. The identifier makes possible unique identification of a respective bit holder system or bit. The identifier can contain further data, for example a bit type, an item number of the bit or bit holder system, and/or an installation date or installation time of the bit or bit holder system.

Alternatively to incrementing of the counter upon actuation of the initiator, an incrementing of the counter can also occur upon detection of an identifier. These alternatives are also intended to apply to all exemplifying embodiments hereinafter.

According to a possible inventive variant, provision can be made that the detection device is embodied to read out a data medium, in particular an electronic data medium, arranged as an identifier on the bit holder system. An electronic data medium allows almost any data to be stored. Those data can contain information that enables unique identification of a respective bit holder system and thus of a bit. Instead of the electronic data medium it is also conceivable to provide another form of identifier, for example in the form of an optically readable data medium. An optically readable data medium can be, for example, a barcode. A barcode of this kind can be arranged inexpensively on the bit holder system. Any form of machine-readable identification is suitable in principle as an identifier for the bit holder system.

If provision is made that the detection device is embodied to read out the identifier in noncontact fashion, no mechanical or electrical connection between the tool and the identifier is then necessary for the transfer of data from the identifier to the detection device. The tool can thus be embodied in accordance with known tools, and can merely have the detection device added to it. Retrofitting of existing tools with a detection device according to the present invention is also conceivable.

In accordance with a particularly preferred variant embodiment of the invention, provision can be made that the detection device is embodied, upon actuation of the at least one initiator, to detect a position on a milling drum of the bit holder system onto which the tool is placed. The position of the bit holder system can be stored, for example, in the identifier and correspondingly read out. The position of the bit holder system can contain a coordinate proceeding in an axial direction of the milling drum and/or a coordinate proceeding in a circumferential direction of the milling drum, for example in the form of an angle indication. The coordinate proceeding in a circumferential direction can be referred, for example, to a previously specified zero line. The zero line then corresponds, for example, to a line proceeding on the circumference of the milling drum tube in the direction of its rotation axis. It is also conceivable to associate with each possible installation position of the bit holder system a unique position number that enables unique identification of the position of a respective bit holder system on the milling drum.

Provision can advantageously be made that the detection device comprises an RFID reading device. An RFID transponder is then associated as an identifier with each of the bit holder systems. RFID transponders are available inexpensively in large quantities, and data that make possible unique identification of a bit holder system can be stored in them. Data that characterize the position of the respective bit holder system on the milling drum can also be stored in them. The RFID transponders can be embodied as active or passive RFID transponders. Passive RFID transponders have the advantage that they do not require their own energy supply. The RFID reading device allows the data of the RFID transponder to be read out in noncontact fashion, i.e. without establishing an electrical or mechanical contact. The result is a simple and inexpensive design for the tool.

Rapid and simple deinstallation and/or installation of the bits can be achieved by the fact that the tool comprises a base part on which a positioning member having a push-off portion and/or having a pull-on portion is movably mounted; and that the positioning member is indirectly or directly coupled onto an actuator. The actuator can be constituted, for example, by a piston-cylinder system or by an electric-motor unit. The push-off portion can be embodied in the form of a drift punch. The push-off portion allows a bit to be driven out of a bit holder. With the aid of the pull-in portion, a bit can be pulled with its bit shank into a bit receptacle of the bit holder. The base part allows the tool to be secured on the bit holder system. The actuator is initiated by actuating the at least one initiator. At the same time, the count status of the counting device for deinstalled and/or installed bits is incremented as a result of the actuation of the at least one initiator. If the tool is designed, for example, for both installation and deinstallation of bits, two initiators can correspondingly be provided, one initiating an installation motion and the second a deinstallation motion of the positioning member. The count status of the counting device for an installed or for a deinstalled bit is then incremented, depending on which of the initiators was actuated. It is conceivable to provide two counting devices, one of which counts the installed bits and one the deinstalled bits. It is thereby possible, for example, to recognize whether all the driven-out bits have been substituted with new ones in the context of a bit change. It is also conceivable to use only one initiator, the functionality of which is switchable between initiating an installation and a deinstallation, or which alternatively initiates installation and deinstallation. Upon actuation of the initiator the count status for deinstalled bits or for installed bits is then incremented, depending on the functionality selected.

Particularly advantageously, provision can be made that at least a part of the detection device, in particular the RFID reading device, is arranged on or in the positioning member or on or in the base part of the tool. That portion of the detection device which is responsible for detecting the identifier, for example the RFID reading device, can thereby be brought into the immediate vicinity of an identifier arranged on the bit holder system, in particular of an RFID transponder arranged on the bit holder, upon installation or deinstallation of a bit. This makes possible unimpeded data exchange between the RFID transponder and the RFID reading device. The data read out from the RFID transponder make possible, for example, the above-described determination of the position of the bit holder system on the milling drum. A bit change can thus be associated with a specific bit holder system and with a position on the milling drum.

To prevent an erroneous actuation of the at least one initiator, during which deinstallation and/or installation of a bit does not occur, from resulting in a change in the determined number of deinstalled and/or installed bits, provision can be made that the detection device is embodied to recognize an actuation of the at least one initiator without occurrence in that context of installation or deinstallation of a bit, and then not to modify the number of detected installed and/or installed bits; and/or that the detection device is embodied not to modify the number of detected installed and/or deinstalled bits upon a repeated actuation of the at least one initiator within a predefined time period; and/or that the detection device is embodied not to modify the number of detected installed and/or deinstalled bits upon a readout of the same identifier repeated within a predefined second time period; and/or that the detection device is embodied not to modify the number of detected installed and/or deinstalled bits upon an actuation of the at least one initiator and in the absence of readout of an identifier. For example, if two successive initiating operations occur within a predefined time period that is selected to be sufficiently short that deinstallation and/or installation of two bits is not possible within the time period, the count status is correspondingly not modified. If an initiating operation is repeatedly carried out successively on the same bit holder system, this can then be recognized based on the fact that the same identifier is read out successively. In this case as well, the count status of the deinstalled and/or installed bit is correspondingly not modified. If no identifier is read out upon initiation of the tool, it can be assumed that the tool is not placed onto a bit holder system and thus that a bit was not deinstalled or installed. In that case as well, no modification of the count status of the counting unit occurs. It is also conceivable for the tool to be embodied to detect the force applied by the tool. The detection device can then be embodied to infer, based on the information regarding the applied force, whether installation or deinstallation of a bit has occurred.

The bit holder system can be embodied in two parts, namely from a base part connected to the milling drum and a replaceable bit holder held therein. Provision is made that the detection device is designed to read out an identifier arranged on a base carrier of the bit holder system and/or an identifier arranged on a replaceable bit holder associated with the base carrier, so that an association of a replaceable bit holder with a base carrier can be detected and checked by the detection device or by a control unit to which the detection device transfers the data. If what is ascertained for a base carrier upon detection of an identifier of a bit holder and a base carrier is, for example, a bit holder different from the one stored for it in the detection device or in the control unit, it can be inferred that the bit holder has been changed. The tool thus also makes possible recognition and detection of changed bit holders.

To allow recognition of a replaced bit holder, provision can also be made that the detection device is embodied, upon actuation of the at least one initiator, to read out the at least one identifier arranged on a bit holder system and to detect the position of the bit holder system on the milling drum; and that the detection device is embodied to detect, by comparing the data read out from the identifier with data stored in the detection device for the position on the milling drum, that a replaceable bit holder at that position has been changed. The identifier is preferably arranged on the replaceable bit holder of the bit holder system.

Advantageously, provision can be made that the detection device comprises a memory and that the data read out from the identifiers, and/or the points in time at which the respective identifiers were read out, are storable in the memory; and/or that the stored data and/or points in time are associated with a count status of the counting device. The data, together with the count status, can thus be stored and transferred to a higher-order control unit. The transfer can be accomplished, for example, once all the worn-out bits of a milling drum have been replaced.

A preferred variant embodiment of the invention provides that the tool comprises a wire-based interface or a radio interface for electronic transfer of data. The interface is connected to the detection device or is part of the detection device. Data can be transferred from the detection device to a control unit, and conversely from a control unit to the detection device, via the interface. It is thereby possible to transfer to the control unit the number of deinstalled and/or installed bits detected by the tool. Said unit can be arranged, for example, in the milling machine. The control unit can then indicate to the machine operator, via an indicator, the number of deinstalled or installed bits. The tool therefore does not need to have its own indicator for displaying the number of exchanged bits. Further data transferred from the identifiers to the tool, for example position data, or data derived therefrom, can also be transferred via the interface to the control unit and evaluated or displayed by it.

In order also to allow data to be transferred to the identifiers arranged on the bit holder systems, provision can be made that the tool and/or the detection device comprises a data interface; and that the data interface is embodied to transfer data to the data medium arranged as an identifier on the bit holder system. It is thereby possible, for example, to transfer a point in time at which a bit was installed on the bit holder system. That can then be read out again upon deinstallation of the bit, and used to determine the service life of the bit. In addition, the data necessary for identification of the respectively associated bit holder system can be transferred from the tool to the identifiers prior to a first use of the identifiers. There is thus no need for further devices that allow writing to the identifiers.

That object of the invention which relates to the bit holder system is achieved in that at least one electronic data medium that can be read out in noncontact fashion is arranged as an identifier on or in the bit holder system; and that the data medium contains information for identification of the bit holder system and/or regarding the position of the bit holder system on the milling drum. Reading out the data media of the bit holder systems arranged on a milling drum allows each of said systems to be uniquely identified, and/or it is possible to determine the position of a particular bit holder system on the milling drum. It is thereby possible, in the context of a bit change, to associate the changed bit with a specific bit holder system and/or with a position on the milling drum. It is thereby possible, for example, to ascertain how often a bit on a specific bit holder system has been changed. When referred to a milling operation carried out by the milling drum, conclusions can then be drawn, from the data thereby obtained, as to the wear behavior of the bits at their respective installation locations on the milling drum. From the wear behavior, prognoses can be created for the future demand for bits as the milling task is continued. Conclusions can be drawn as to the material properties of the milled substrate. Based on this information it becomes possible, for example, to adjust the machine parameters of the milling machine in optimized fashion in such a way that maximum possible milling performance is achieved with minimum wear on the bits. Machine utilization efficiency can thereby be increased, and costs for machine utilization thereby reduced. Advantageously, the data media are arranged not in or on the bits, but in or on the bit holder systems. A data medium is thus not also replaced when a bit change is required, but can instead be used in accordance with the service life of the bit holder system. The number of data media required for monitoring the replacement of and wear on bits can thereby be significantly reduced as compared with known systems in which the data media are arranged in or on the bits.

A long life expectancy for the data media can be achieved by the fact that the data medium is arranged in a region of the bit holder system which is protected from abrasion.

In accordance with a particularly preferred variant embodiment of the invention, provision can be made that the data medium is an active or passive RFID transponder. RFID transponders are offered inexpensively in large quantities, and data that make possible unique identification of a bit holder system, or of its position on a milling drum, can be stored in them. It is also possible to provide RFID transponders that make it possible to modify the stored data later. Passive RFID transponders furthermore have the advantage that they do not require a separate power supply.

Provision can advantageously be made that the data medium contains information regarding the point in time at which a bit held in the bit holder system was installed. Upon removal of a bit that has reached the wear limit, the service life of the bit under the past operating conditions of the milling drum and milling machine can thus be identified.

Provision can be made that the bit holder system comprises a bit holder connected fixedly to the milling drum, and that the at least one data medium is arranged on or in the bit holder; or that the bit holder system comprises a base carrier connected fixedly to the milling drum and a replaceable bit holder detachably connected to the base carrier, and that at least one data medium is arranged on or in the base carrier and/or on or in the replaceable bit holder. In the case of a bit holder connected fixedly to the milling drum, for example by way of a welded join, the position data of the bit holder system can be uniquely associated with the bit holder and stored in the data medium arranged on or in the bit holder. In the case of a two-part bit holder system with which a base carrier and a bit holder, connected replaceably thereto, are associated, the position data on the milling drum can be uniquely associated with the base carrier fixedly connected to the milling drum, and thus stored in a data medium arranged on the base carrier. A replaceable bit holder can firstly be installed on any base carrier. If both the replaceable bit holder and the base carrier in which the bit holder is held comprise a data medium, a unique association between a base carrier and a replaceable bit holder installed thereon can then be established based on the stored data. The position of the replaceable bit holder on the milling drum can thus also be uniquely determined by way of that association. Upon replacement of the bit holder, for example because of advanced wear, a new bit holder having a new identifier is associated with the base carrier, this being recognized when the data media arranged on the base carrier and on the replaceable bit holder are read out. Replacement of a bit holder can thereby be verified and detected. Based on the number of replaced bit holders thereby ascertained, it is possible to infer their service life under the past operating conditions of the milling drum and the milling machine. This allows a prognosis as to the future demand for bit holders in order to continue the milling task.

That object of the invention which relates to the method is achieved in that the number of bits installed and/or deinstalled using the tool is detected by a detection device arranged on the tool; and/or that the position of a bit installed and/or deinstalled using the tool is detected by the detection device arranged on the tool; and/or that the position and a unique identification of a bit holder system on which a bit is deinstalled or installed is detected by the detection device. The number of bits replaced, and thus their wear behavior, can be inferred directly from the number of bit installed and/or deinstalled. Further parameters, for example a utilization duration of the bits, can also be considered. It is also possible to take into consideration the machine parameters that are provided in the context of the milling jobs carried out and which the milling machine was operated, or to consider the material being milled. If the position of the bits or bit holders on the milling drum is also detected, spatially resolved wear monitoring can then be accomplished. It is thereby possible, for example, to evaluate whether elevated wear exists in certain regions of the milling drum. A change of a replaceable bit holder can be inferred if, in a context of successive bit changes at one position of the milling drum, a bit holder system having a different identification is detected.

Simple and reliable determination of the position of a replaced bit or of a replaced replaceable bit holder on the milling drum can be accomplished by the fact that the position of a deinstalled and/or installed bit, and/or the position of a replaceable bit holder on which a bit is deinstalled and/or installed, is detected by reading out an identifier arranged on the bit holder system. The detection unit arranged on the tool preferably comprises means with which the identifier can be read out automatically.

