Measuring device

Abstract

Measuring device (1) for a machine tool comprising a measuring probe (2) and a detection device (3), wherein the measuring probe (2) and the detection device (3) are designed for wireless signal transmission at least from the measuring probe (2) to the detection device (3), characterized in that a measuring unit (23) is provided with which a signal level of a received signal can be measured, and that the detection device (3) is designed to transmit information to the measuring probe (2) on the basis of which a change in a signal level with which the measuring probe (2) transmits takes place, and that the measuring probe (2) and the detection unit (3) are designed for wireless signal transmission using infrared light.

Description

[0001] The invention relates to a measuring device according to the preamble of claim 1.

[0002] In the field of mechanical engineering, measuring devices for machine tools are known in a wide variety of designs. Such measuring devices in machine tools eliminate the need for separate devices for checking dimensional accuracy on workpieces and machining tools, and allow corresponding tests to be performed more quickly and efficiently during production. In many cases, the measuring device comprises a detection device and a measuring probe, which are designed as separate components. The aim is for the measuring probe to be movable and compact, allowing it to be guided even along difficult surfaces, especially in the cavities of a body.

[0003] To allow the probe to move along a body's surface as unhindered as possible, it is also known to transmit signals from the probe to the detection device wirelessly, e.g., using radio waves. However, wireless signal transmission is comparatively more susceptible to interference. To avoid interruptions in signal transmission, the probe is set to a comparatively high transmission power, which can result in increased maintenance effort.

[0004] DE 10 2012 211 612 A1 and US 2012 / 0004886 A1 are mentioned as state of the art.

[0005] The object of the present invention is to provide a measuring device which is improved, in particular with regard to maintainability.

[0006] The problem is solved by a measuring device having the features of claim 1.

[0007] Preferred and advantageous embodiments of the invention are specified in the subclaims.

[0008] The invention is based on a measuring device for a machine tool, comprising a measuring probe and a detection device. The measuring probe and the detection device are designed for wireless signal transmission, at least from the measuring probe to the detection device. The core of the invention is that a measuring unit is provided with which a signal level of a received signal can be measured, and that the detection device is designed to transmit information to the measuring probe, on the basis of which a change in the signal level at which the measuring probe transmits takes place.

[0009] The invention is based on the consideration that the measuring probe consumes a significant portion of the energy, possibly even the majority, by transmitting signals. The invention offers the advantage that the measuring unit can be used to determine whether the measuring probe is using a higher transmission power than required for reception. The measuring probe is advantageously designed, in particular, to automatically change the signal level at which the measuring probe transmits, thereby advantageously enabling the measuring probe to adapt its energy consumption to a level required for reliable communication. The detection device is advantageously integrated into such an adaptation.

[0010] A preferred embodiment of the invention provides for the measuring unit to be integrated into the detection device. This means that the measuring unit does not place a load on the power supply of the measuring probe.

[0011] A further embodiment of the invention involves integrating the measuring unit into the probe. This allows a probe to independently monitor a signal level, e.g., based on reflected signals emitted by the probe.

[0012] According to the invention, the measuring probe and the detection unit are designed for wireless signal transmission using infrared light. Furthermore, the measuring probe and the detection unit can be designed for wireless signal transmission using radio waves.

[0013] Radio waves offer the advantage of a lower dependence of reception quality on distance and can also be received over a transmission path that is not connected by a straight, clear path between transmitter and receiver.

[0014] In contrast, infrared light offers the advantage of being less susceptible to interference and a simpler transmitter and receiver design using semiconductor diodes and, if necessary, transistors. Preferably, the detection device and the measuring probe are designed for bidirectional communication. This offers the advantage that signal transmission is symmetrical in both directions, for example, between the measuring probe and the detection device, allowing the reception quality of signals to be checked at both ends of the transmission path.

[0015] Furthermore, it is preferred that the detection device is designed to transmit information to the probe, with which a signal level can be set on the probe for subsequent signal transmission. The detection device can transmit information, for example, a measured value, as digital data. Optionally, the detection device can also directly transmit a value for changing the transmission power of the probe.

[0016] Furthermore, it is preferred that the detection device is designed to transmit the measured signal level to the measuring probe.

[0017] In order to monitor the quality of a signal transmission using a measuring unit in the measuring probe, the detection device is preferably designed to regularly transmit a reference signal with a predetermined signal level. The detection device can transmit the reference signal with a transmission power that can be received reliably and without failure by the measuring probe. Furthermore, this embodiment of the invention enables rapid adjustment of the transmission power of the measuring probe, as the measuring unit is preferably integrated into the measuring probe.

[0018] Preferably, a control function is designed to determine a changed signal level, by means of which a distance between the measuring probe and the detection device is calculated into a changed signal level of the measuring probe for transmitting signals. In particular, it is preferred that a control function for adjusting the signal level of the measuring probe is designed such that a position of the next measuring position is evaluated in order to change the signal level of the measuring probe before the next measuring position is reached. In this way, a receivable and adjusted signal level can be achieved, even in cases in which the measuring probe is moved over a greater distance, possibly without continuously transmitting signals. In particular, situations can be taken into account in which the measuring probe penetrates areas of a workpiece that make signal transmission difficult.Furthermore, it is preferred that a control function be implemented for determining a changed signal level, by which an attenuation coefficient reflecting environmental influences on the transmission path between the measuring probe and the detection device is calculated into the changed signal level of the measuring probe for transmitting signals. This also ensures a comparatively more reliable and energy-saving signal transmission.

[0019] A preferred embodiment of the invention provides that the measuring probe is designed for attachment to a tool holder of the machine tool. This advantageously avoids additional effort required for the use of the measuring probe.

[0020] Preferably, an energy storage device, e.g., an electrochemical energy storage device such as a battery or accumulator, is housed in the measuring probe. This offers the advantage that not only signal transmission but also power supply is advantageously wireless.

[0021] The detection device preferably has a communication interface for connection to a machine control system of the machine tool. This allows information, such as position data, to be made available to the detection device for adjusting the transmission power.

[0022] Two exemplary embodiments of the invention are explained in more detail below with reference to the drawings, highlighting further advantages. They show: Fig. 1 schematic perspective view of a measuring device according to the invention, Fig. 2 schematic block diagram of the measuring device according to the invention, Fig. 3 schematic block diagram of a second embodiment.

[0023] The Fig. 1 shows a measuring device 1 according to the invention with a measuring probe 2 and a detection device 3.

[0024] A stylus 5 with a stylus tip 6 is attached to a housing 4 of the measuring probe 2. The stylus 5 is mounted on the housing 4 in such a way that the measuring pin 5 triggers a measurement and its transmission to the detection device 3 when the measuring tip 6 touches a surface (not shown) of a workpiece (not shown) or a tool (not shown) on a machine tool (not shown).

[0025] The housing 4 of the measuring probe 2 has a mounting section 7, which is adapted, for example, to a tool holder (not shown) of a machine tool. This allows the measuring probe 2 to be guided along a workpiece by a machine tool with the same precision as, for example, a tool of the machine tool.

[0026] Preferably, the measuring probe 2 is designed for operation with an electrical energy storage device (not shown), such as a battery or an accumulator, which is accommodated in the housing 4.

[0027] For wireless signal transmission to the detection device 3, several transmitting elements 8 and receiving elements 9 are mounted on the housing 4. These elements are protected from environmental influences, such as dirt, by a transparent cover 10. The transmitting elements 8 and receiving elements 9 are preferably designed for bidirectional signal transmission using infrared light to the detection device 3. The transmitting and receiving elements 8 and 9 are arranged at several different locations on the housing 4 to ensure signal transmission in different positions.

[0028] The detection device 3 is intended for attachment to the machine tool (not shown), in particular at a fixed location. For example, a housing 11 of the detection device 3 can be fastened to the machine tool with two screws 12. The housing 11 has a preferably transparently covered window 11a. A receiving element 15 and a transmitting element 14 are arranged in the window 11a. Using a cable 13, the detection device 3 can be connected to, for example, the machine tool (not shown) for power supply and for exchanging signals and data.

[0029] A signal sent from the measuring probe 2 to the detection device 3 is exposed to influences along a transmission path S that reduce the signal level upon reception compared to that upon transmission. The signal level receivable at the receiving element 15 is influenced, for example, by a variable distance of the transmission path S between the measuring probe 2 and the detection device 3 or, for example, by obstacles that block the shortest, straightest transmission path.

[0030] In Fig. Figure 2 shows a measuring device 1 according to the invention in block diagram form. An electronics unit 16 of the measuring probe 2 comprises a transmitting unit 17 and a receiving unit 18. The transmitting elements 8 are connected to the transmitting unit 17 and can be controlled by it for signal transmission. The receiving elements 9 are connected to the receiving unit 18, with which signals from the detection device 3 can be received at the measuring probe 2. All parts of the electronics unit 16, including the transmitting and receiving elements 8 and 9, can be supplied with electrical energy by a battery or accumulator.

[0031] The detection device 3 has its own electronic unit 20, which includes a receiving module 21 and a transmitting module 22. The receiving element 15 of the detection device 3 is connected to the receiving module 21, and the transmitting element 14 is connected to the transmitting module 22. The detection device additionally has a measuring unit 23. The measuring unit 23 is connected to the receiving module 21 in such a way that the signal levels of signals received at the receiving element 15 can be determined with the measuring unit 23.

[0032] The measuring unit 23 can be designed to compare a signal level of a received signal level with a predetermined lower limit value of the signal level. In particular, the measuring unit 23 can determine a correction value, e.g., a change value or e.g., a target value, by calculating the difference between the lower limit value and a measured signal level, which can be transmitted to the measuring probe 2 via the transmitting module 22. The correction value can be received at the measuring probe 2 by the receiving element 9 and the receiving unit 18. The electronics unit 16, in particular the transmitting unit 17, is designed to adapt the transmission power according to the received correction value and, in particular, to increase it, thereby ensuring the transmission of subsequent measurement signals.

[0033] Furthermore, the measuring unit 23 can be configured to determine when an upper limit value for received signals has been exceeded and to determine a corresponding correction value for reducing the transmission power at the measuring probe 2. By transmitting a correction value for reducing the transmission power, the energy consumption in the measuring probe 2 can be reduced, whereby replacing or recharging an energy storage device (not shown) of the measuring probe is required comparatively less frequently.

[0034] The measuring device 1 according to the embodiment just described is designed primarily for continuous monitoring and adjustment of the transmission power of the measuring probe 2 in the detection unit. Increased energy consumption, which may arise from additional electronic components, can be relatively easily compensated for in the detection device 3. A further advantage is that the signal level of the signal transmission is limited, at least temporarily, whereby the operating environment of the measuring device 1 is less affected by signal transmission.

[0035] A second embodiment of a measuring device 1 according to the invention is shown in Fig. 3. The measuring device 1 can be mechanically as shown in Fig. 1 shown.

[0036] The measuring probe 2 is equipped with an electronics unit 16 comprising a transmitting unit 17 and a receiving unit 18. The transmitting unit 17 is intended to control transmitting elements 8, in particular for transmitting measurement signals. One or more receiving elements 9 are connected to the receiving unit 18.

[0037] The electronics unit 16 of the measuring probe 2 also comprises a measuring unit 23 which is designed to measure the signal level of signals received by the receiving unit 18.

[0038] The electronics unit 20 of the detection device 3 has a receiving module 21, in particular for receiving measurement signals or measurement data, and a transmitting module 22. The transmitting module 22 can be used to regularly transmit a reference signal with a constant signal level. Preferably, the signal level of the reference signal on the electronics unit 20 can be adjusted such that the reference signal can be received on the measuring probe 2 in all intended measuring positions that can be provided during the testing of a workpiece (not shown) or a tool (not shown). The transmitting unit 22 and the transmitting element 14 can be supplied with the electrical power required for transmission, for example by the machine tool, without being subject to restrictions such as the limited storage capacity of a battery.

[0039] The measuring unit 23 can be used to determine a signal level or a change in the signal level of the reference signals on the measuring probe 2, which the detection device 3 can transmit. The electronics unit 16 is designed to regularly evaluate the measured signal level of received reference signals during a measuring process. For this purpose, the electronics unit 16 can be designed to compare a measured signal level, for example, with a predeterminable target value. In addition, the electronics unit 16 can be used to check whether a measured signal level of a received reference signal lies within predefined limit values ​​of the signal power. By means of a corresponding comparison or a corresponding check, change values ​​for a transmission power with, for example,of the electronics unit 16 in order to make any necessary adjustments to the signal level of the transmitting unit 17 for reliable and energy-saving transmission of measurement signals to the detection unit 3. In particular, the electronics unit 16 can comprise a circuit (not shown) for regulation or control, which regularly, in particular continuously, adjusts the transmission power, e.g. of the transmitting unit 17, to a signal level measured by the measuring unit. An adjustment of the transmission power of the measuring probe 2 is therefore advantageously no longer dependent on the reception of signals at the detection device 3. Therefore, for example, an excess power reserve for securing signal transmissions of the measuring probe 2 can be reduced or completely avoided. List of reference symbols: 1 measuring device 2 measuring probes 3 Recording device 4 housings 5 stylus 6 Probe tip 7 Assembly section 8 transmitting element 9 Receiving element 10 Transparent cover 11 housings 11a Window 12 screw 13 cables 14 transmitting element 15 Receiving element 16 Electronic unit 17 Transmitter unit 18 Receiving unit 20 Electronic unit 21 Transmitter module 22 Receiver module 23 measuring unit

Claims

[1] Measuring device (1) for a machine tool, comprising a measuring probe (2) and a detection device (3), wherein the measuring probe (2) and the detection device (3) are designed for wireless signal transmission at least from the measuring probe (2) to the detection device (3), characterized by that a measuring unit (23) is provided with which a signal level of a received signal can be measured, and that the detection device (3) is designed to transmit information to the measuring probe (2), on the basis of which information a change in a signal level with which the measuring probe (2) transmits takes place, and that the measuring probe (2) and the detection unit (3) are designed for wireless signal transmission with infrared light. [2] Measuring device (1) according to claim 1, characterized by that the measuring unit (23) is integrated into the detection device (3). [3] Measuring device (1) according to one of the preceding claims, characterized bythat the measuring unit (23) is integrated into the measuring probe (2). [4] Measuring device (1) according to one of the preceding claims, characterized by that the measuring probe (2) and the detection unit (3) are designed for wireless signal transmission using radio waves. [5] Measuring device (1) according to one of the preceding claims, characterized by that the detection device (3) and the measuring probe (2) are designed for bidirectional communication. [6] Measuring device (1) according to one of the preceding claims, characterized by that the detection device (3) is designed to transmit information to the measuring probe (2), with which a signal level can be set on the measuring probe (2) for subsequent signal transmission. [7] Measuring device (1) according to one of the preceding claims, characterized by that the detection device (3) is designed to transmit the measured signal level to the measuring probe (2). [8] Measuring device (1) according to one of the preceding claims, characterized by that the detection device (3) is designed to regularly emit a reference signal with a predetermined signal level. [9] Measuring device (1) according to one of the preceding claims, characterized by that a control function is designed to determine a changed signal level, by means of which a distance between the measuring probe (2) and the detection device (3) is included in a changed signal level of the measuring probe (2) for sending signals. [10] Measuring device (1) according to one of the preceding claims, characterized bythat a control function is designed to determine a changed signal level, by means of which an attenuation coefficient, which reflects environmental influences on the transmission path S between the measuring probe (2) and the detection device (3), is included in a changed signal level of the measuring probe (2) for sending signals. [11] Measuring device (1) according to one of the preceding claims, characterized by that the measuring probe (2) is designed to be attached to a tool holder of the machine tool. [12] Measuring device (1) according to one of the preceding claims, characterized by that an energy storage device is housed in the measuring probe (2). [13] Measuring device (1) according to one of the preceding claims, characterized by that the detection device (3) has a communication interface for connection (13) to a machine control of the machine tool. [14] Measuring device (1) according to one of the preceding claims, characterized by that a control function for adjusting the transmission signal level of the measuring probe (2) is designed such that a position of a next measuring position is evaluated in order to change the transmission signal level of the measuring probe (2) before the next measuring position is reached.

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