EP1951462B1 - Display device for positioning a tool on a workpiece - Google Patents

Description

The invention is based on a display device for positioning a tool on a workpiece according to the preamble of claim 1, as shown in FIG US 2003/221 306 is known.

When machining a workpiece, such as a wall or floor slab, it may happen that a position specification for, for example, a hole in the ceiling is made from a side of the ceiling, but from which drilling can not be made. The hole is then made from the other side of the ceiling, with the desired position also being marked on this side of the ceiling. For this purpose, display devices are known with a transmitter, which is fixed in the predetermined position on the side of the wall or ceiling from which can not be drilled. The transmitter sends a transmission signal through, for example, the wall. With the aid of a mobile receiver, the corresponding desired position is searched on the processing side of the wall, the position there marked and, for example, the hole drilled at this position.

Advantages of the invention

The invention is based on a display device for positioning a tool on a workpiece with a transmitter for emitting a workpiece penetrating signal and a receiver for receiving the signal.

It is proposed that the receiver comprises an array of sensor elements. It can be dispensed with a lead around a single receiver on the transmitter opposite side of the workpiece, and a desired position or a location to be determined can be easily determined and displayed for example on a digital display or directly by one or more lamps. For this purpose, the arrangement can be fastened to the side of the workpiece opposite the transmitter, for example the wall, and the machining point can be read directly at the desired position.

As an arrangement, a grid arrangement is advantageous, for example a rectangular grid arrangement. The arrangement expediently comprises means for attachment to the workpiece, for example adhesives. The display device serves for the indirect or immediate display of a desired position. The workpiece is advantageously arranged between the transmitter and the receiver. The transmitter can transmit in the kilo, megahertz or gigahertz range for transmission Coupling electromagnetic waves in the form of modulated signals or magnetic fields or electric fields in the workpiece. Frequency ranges are all authorization-free radio bands (ISM bands). Particularly advantageous is a so-called UWB transmitter (Ultra Wide Band), which sends a very broadband signal, for example in the form of one or more pulses, in a frequency range between 500 MHz and 20 GHz. In such an operation, only a very low transmission power is necessary because a disturbance of individual frequencies is harmless. In addition, large amounts of data, for example for evaluating a workpiece thickness or a workpiece material, can be sent and received quickly. In addition, several sensors can be individually addressed quickly by corresponding signal parts. As an alternative to a transmitter provided for a pulsed operation, advantageously a CW radar or a PN radar can be used. In a CW (Continuous Wave) radar, a frequency ramp is emitted and a reflected frequency is compared with a frequency being radiated. With PN (Pseudo Noise) radar, continuous noise is generated and a desired signal is placed over the noise.

As a transmitter, a permanent magnet, an electromagnet, a coil, a capacitor arrangement or an arrangement for generating electrical field peaks can be used for signal generation. When using electromagnetic waves as a transmission signal and antennas in the sensor elements, the evaluation of the transmission signal on the received field strength can be done. When using capacitive surfaces, the evaluation can be made on the strength or change of the electric field. Also possible is the use of Surface Acustic waves, where the evaluation is carried out by the excitation of resonant structures, for example in a semiconductor material, and the conversion into an electrical signal.

In a preferred embodiment, the sensor elements are so-called RFID elements (Radio Frequency Identification), since such elements from mass production can be produced particularly favorably. Such RFID elements are generally known and can react to the transmission signal with an identification signal whose strength and signal content is evaluated by a computer. When using magnetic waves as a transmission signal, the sensor elements may contain coils and the evaluation can be done on the received field strength. When using a static magnetic field magnetic sensors, such as Hall sensors, can be used, combined with the evaluation of the field strength. When using an electric field, electric field sensors, for example capacitor arrangements, can be used in conjunction with the evaluation of the electric field strength or the electrical charge.

An attachment of the arrangement with sensor elements on the workpiece can be particularly easily done when the sensor elements are mounted in a carrier assembly, in particular in predetermined positions to each other. The sensor elements can be fastened in or on the carrier arrangement. Particularly advantageous is the use of a support mat as a carrier arrangement, which in particular can be rolled up and in this way is particularly easy to transport.

A high spatial resolution in the search or display of the transmitter, for example, opposite desired position can be achieved if at least one sensor element is movable during a receiving operation relative to the carrier assembly. In particular, all the sensor elements fastened to the carrier arrangement are movable relative to the carrier arrangement during a receiving operation, expediently on an inner carrier arrangement which is movable relative to the carrier arrangement as a whole.

A particularly simple display of a location to be determined can be achieved if the sensor elements have an optical signal means. In this case, the luminosity of the signal means is expediently substantially continuously variable, as a result of which, for example, a field strength can be visually displayed directly.

In a further embodiment of the invention, the display device has an optical signal means which can be controlled by an evaluation unit and which is arranged at a predetermined distance from the sensor elements. As a result, a location to be determined can be displayed substantially independently of the positions of the sensor elements.

If the signal means comprises a matrix of signal elements, the location to be determined can be displayed particularly simply and accurately.

In particular, when using short transmit pulses, it is advantageous if the location to be determined is determined by an evaluation, stored and displayed. Includes the display device expediently an evaluation unit, which is prepared for outputting a location-indicating signal independently of a current transmission process of the transmitter.

The display device can be made particularly inexpensive and robust when the sensor elements are provided for emitting a signal through the workpiece. An evaluation unit can be connected to the transmitter, so that the sensor arrangement does not require a direct connection to the evaluation unit and can therefore be designed very simply.

Advantageously, the display device comprises an evaluation unit for receiving signals of the sensor elements and at least one coding means for providing a signal from a sensor element with a code associated with the sensor element. As a result, the evaluation unit can distinguish the sensor elements based on their codes and, for example, make a workpiece thickness determination by determining a relative position of the sensor elements to the transmitter or an additional receiver.

Expediently, the display device comprises an evaluation unit which is provided to determine a workpiece thickness from a signal from or to at least one sensor element, for example from a determination of the signal propagation time.

A particularly accurate determination of the workpiece thickness can be made by an evaluation unit, which is provided to determine a workpiece thickness from a comparison of sensor signals. The sensor signals can be transmitted by the sensor elements on command of the evaluation unit or by, for example, excitation of a transmission signal from the transmitter by the sensor elements. drawing

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

eine schematische Darstellung einer Anzeigevorrichtung an einer Wand,

Fig. 2

eine Trägeranordnung der Anzeigevorrichtung mit Sensorelementen,

Fig. 3

einen Ausschnitt einer alternativen Anzeigevorrichtung mit einem Signalelementgitter,

Fig. 4

ein Anzeige- bzw. Auswerteschema zur Bestimmung einer Werkstückdicke,

Fig. 5

eine Trägeranordnung mit einer daran beweglichen Trägerinnenanordnung und

Fig. 6

ein schematisches Sende-, Empfangs- und Auswerteschema.

Show it:

Fig. 1

a schematic representation of a display device on a wall,

Fig. 2

a carrier arrangement of the display device with sensor elements,

Fig. 3

a section of an alternative display device with a signal element grid,

Fig. 4

a display or evaluation scheme for determining a workpiece thickness,

Fig. 5

a carrier assembly with a movable carrier inner assembly and

Fig. 6

a schematic transmission, reception and evaluation scheme.

Description of the embodiments

FIG. 1 shows a display device with a transmitter 2, which is positioned and fixed on one side of a wall running workpiece 4. Opposite the transmitter 2, a carrier assembly 6 with a number of sensor elements 8 is attached to the wall. A signal 10 emitted by the transmitter 2 is detected by a series of sensor elements 8.

FIG. 2 shows the support structure 6 made of solid fabric as a mat, are mounted on the 6 x 12 sensor elements 8 in such a way that they are movable in the direction of arrows 14 respectively to just below the adjacent sensor element 8 relative to the support assembly 6. On the sensor elements 8 each optical signal elements 12 are attached in the form of LEDs. The support assembly 6 itself has four retaining means 16 for attachment to the workpiece 4, which are designed as easily replaceable adhesive.

To determine a desired or to be determined, the transmitter 2 opposite position 18, the transmitter 2 is fixed in a send position on the workpiece 4, in which, for example, a pushed forward from the other side of the workpiece 4 wall breakthrough should exit from the wall. Subsequently, the support assembly 6 is attached to the sensor elements 8 on the other side of the workpiece 4, at a position where one suspects the desired position 18, which is opposite to the transmission position of the transmitter 2. Now, the transmitter 2 is turned on by means of a knob 20 and radiates its conical signal 10 in the workpiece 4, which is detected by the sensor elements 8. The sensor elements 8 detecting the signal 10 then send a signal 10 to the respectively associated signal element 12, when the signal 10 exceeds a preset signal strength. At the in FIG. 2 For example, the four signal elements 12 which are arranged around the desired position 18 are illuminated, for example. The number of luminous signal elements 12 in this case depends essentially on the distance of the carrier arrangement 6 from the transmitter 2. The further the carrier arrangement 6 is remote from the transmitter 2, the more signal elements 12 lie within the conical signal 10 and illuminate accordingly. With a very thin wall, it may happen that the conical signal 10 radiates between the sensor elements 8 and does not hit any of them. By a slight displacement of the sensor elements 8 in the direction of the arrows 14, the signal 10 can still be found and the desired position 18 are located very accurately. At the in FIG. 2 As shown, by moving the signal elements 12, the circular boundary of the signal 10 can also be very accurately detected by an operator and the desired position 18 can be very accurately recognized as the center of this circle.

In order to additionally determine a thickness of the workpiece 4, the display device is equipped with a transmitting device, by which the sensor elements 8 upon actuation of a button 22 each have a signal 32 (FIG. FIG. 5 ). The transmitter 2, which is prepared for receiving and with the aid of an evaluation unit 24 for evaluating these signals 32, evaluates the signals 32 of the sensor elements 8 and determines therefrom the thickness of the workpiece 4, which is displayed on a not shown display means of the transmitter 2. The thickness can be determined by each sensor element 8 emits a corresponding coded signal 32, through which the Evaluation unit 24 can clearly identify the origin of the signal 32. From the difference of the transit times of the signals 32 from the sensor elements 8 to the transmitter 2, the evaluation unit 24, in conjunction with the known by the coding positions of the sensor elements 8 on the support assembly 6, the distance of the next sensor elements 8 calculate. The only prerequisite for this is that the carrier assembly 6 rests as flat as possible on the workpiece 4. A synchronization between the sensor elements 8 and the transmitter 2 is not necessary in a planar alignment of the carrier assembly 6.

FIG. 3 shows a further carrier assembly 6 of a display device with a number of designed as RFID elements sensor elements 8 and signal elements 12. Substantially equal components are basically numbered by the same reference numerals. With respect to the same features and functions can be to the description of the embodiment of FIG. 2 The following description is based essentially on the differences from the exemplary embodiment of FIG FIG. 2 limited. The sensor elements 8 are immovably fixed to the support assembly 6 and each carry a signal element 12. In addition, further signal elements 12 are attached to the support assembly 6 itself. Due to the close arrangement of all signal elements 12, a desired position 18 can be determined very accurately. From the number of luminous signal elements 12, an operator can also estimate the distance of the transmitter 2 from the signal elements 12.

The transmitter 2 transmits its signal 10 in the form of one or more ultrashort, energetically very weak pulses, by which the signal 10 receives an ultra-wide frequency range and is largely insensitive to interference. The desired position 18, which is stored by the evaluation unit 28 and independent of the existence of the signal 10 by the Signal elements 12 is displayed. To output the desired position 18 for the operator, the evaluation unit 28 can now for example illuminate all the signal elements 12 arranged within the signal 10, as in FIG FIG. 3 is shown. From the geometry of the entirety of the illuminated signal elements 12, an operator can estimate the position of the desired position 18 and a wall thickness. Alternatively, the evaluation unit 24 controls only that signal element 12 which is arranged in the immediate vicinity of the desired position 18.

In FIG. 4 is shown schematically, which influence the workpiece thickness has on the number and distribution of the responsive sensor elements 8. From the transmitter 2, the signal 10 is tapered in, for example, a wall. If the wall has a thickness A, then the spatial propagation of the signal 10 is relatively small, so that an arrangement of sensor elements 8 mounted on the side of the wall opposite the transmitter 2 only with this small spatial extent with, for example, seven sensor elements 8, as in FIG FIG. 4 shown, appeals. In the case of a thicker wall with a thickness B, the spatial extent of the signal 10 emerging from the wall is substantially greater and detects more sensor elements 8, for example eight sensor elements 8 and 32 signal elements 12. From the number of signal elements 12 controlled by the evaluation unit 28, an operator, insofar as he is familiar with the expansion cone of the signal 10, can estimate the thickness of the wall. If the determination of the wall thickness takes place electronically, the evaluation unit 24 can calculate the thickness from the number and position of the reacting sensor elements 8 and correspondingly on an output unit 26 (FIG. FIG. 3 ) output.

FIG. 5 schematically shows the display method for displaying the desired position 18 and the determination method for determining the thickness of the workpiece 4. The transmitter 2 couples the signal 10 in the workpiece 4, the signal 10 passes through the workpiece 4 and is registered by sensor elements 8. The sensor elements 8 are connected to the evaluation unit 28, which determines the desired position 8 and optionally the thickness of the workpiece 4 from the signals 30 of the sensor elements 8. Depending on the exemplary embodiment, the evaluation unit 28 can cause the sensor elements 8 to emit further signals 32, which pass through the workpiece 4 and are received by a transmitting antenna of the transmitter 2, which can simultaneously be the receiving antenna of the transmitter 2. From this signal 32, the evaluation unit 24 can determine the workpiece thickness.

Another embodiment is in FIG. 6 shown. The carrier assembly 6 has an inner support assembly 34 to which the sensor elements 8 are fixed immovably. However, the inner support assembly 34 itself is movable in the direction of arrows 36 relative to and within the support assembly 6. To determine the desired position 18 can the carrier assembly 6 positioned on the workpiece 4 and the also positioned transmitter 2 are turned on. A signal cone is registered by a number of sensor elements 8, the signal of which is in turn supplied to the evaluation unit 28. From the number and position of the reacting sensor elements 8 and their different reaction times, which results from the different transit time of the signal 10 from the transmitter 2 to the transmitter 2 differently distant sensor elements 8, the evaluation unit 28 calculates the thickness of the workpiece 4 and outputs them on the output unit 26. In addition, the evaluation unit 28 outputs the desired position 18 in the form of coordinates, in FIG. 6 For example, the evaluation unit 28, the relative position of the inner support assembly 34 relative to the carrier assembly 6 is known. The accuracy with which the desired position 18 can be specified depends on the distance of the sensor elements 8 from each other.

To increase this accuracy, an operator can now move the inner support arrangement 34 back and forth in two dimensions relative to the support arrangement 6, the sensor elements 8 receiving the signal 10 of the transmitter 2 at several intervals or continuously and transmitting corresponding signals 30 to the evaluation unit 28. From these signals 30 and their change in the movement of the inner support assembly 34 - or the change in the responsive sensor elements 8 - the evaluation unit 28 with very high accuracy determine the desired position 18 and output accordingly on the output unit 26.

reference numeral

2

transmitter

4

workpiece

6

carrier assembly

8th

sensor element

10

signal

12

signal element

14

arrow

16

holding means

18

position

20

stud

22

stud

24

evaluation

26

output unit

28

evaluation

30

signal

32

signal

34

Internal substrate assembly

36

arrow

A

thickness

B

thickness

Claims (10)

1. Display device for positioning a tool on a workpiece (4), having a transmitter (2) for emitting a signal (10), which penetrates the workpiece (4), and a receiver for receiving the signal (10), characterized in that the receiver comprises an arrangement of sensor elements (8).
2. Display device according to Claim 1, characterized in that the sensor elements (8) are fastened in a carrier arrangement (6).
3. Display device according to Claim 2, characterized in that at least one sensor element (8) can be moved relative to the carrier arrangement (6) during a receiving operation.
4. Display device according to one of the preceding claims, characterized in that the sensor elements (8) have an optical signalling means.
5. Display device according to one of the preceding claims, characterized by an optical signalling means which can be driven by an evaluation unit (28) and is arranged at a predetermined distance from the sensor elements (8).
6. Display device according to Claim 5, characterized in that the signalling means comprises a matrix of signalling elements (12).
7. Display device according to one of the preceding claims, characterized by an evaluation unit (28) which is prepared to output a signal which indicates the location, irrespective of an instantaneous transmitting operation of the transmitter (2).
8. Display device according to one of the preceding claims, characterized in that the sensor elements (8) are provided for the purpose of emitting a signal (32) through the workpiece (4).
9. Display device according to one of the preceding claims, characterized by an evaluation unit (24, 28) which is provided for the purpose of determining the thickness of a workpiece from a signal (10, 32) from at least one sensor element (8).
10. Display device according to one of the preceding claims, characterized by an evaluation unit (24, 28) which is provided for the purpose of determining the thickness of a workpiece from a comparison of sensor signals.

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