FR2548349A1 - METHOD AND DEVICE FOR INSPECTING A PART WITH A PROBE - Google Patents

Abstract

VARIOUS TECHNIQUES ARE DESCRIBED FOR CONTROLLING A PARTS INSPECTION PROCESS, USING A BATTERY-POWERED PROBE FOR COMING INTO CONTACT WITH THE PART, AND TRANSMITTING INFORMATION TO A CONTROLLER IN A MACHINE TOOL SYSTEM. IN AN EMBODIMENT, THE ENERGY OF THE BATTERIES IS APPLIED TO A PROBE TRANSMISSION CIRCUIT IN RESPONSE TO AN INFRARED RADIATION FLASH. IN ANOTHER EMBODIMENT, THE PROBE IS TURNED ON BY COMING INTO CONTACT WITH A REFERENCE SURFACE. IN BOTH MODES OF EMBODIMENT, A TIMER IS USED TO AUTOMATICALLY DISCONNECT THE BATTERIES AFTER A CERTAIN LAP OF TIME. IN THIS WAY, THE LIFETIME OF THE BATTERIES IS EXTENDED.

Description

1. The present invention relates to parts inspection systems and,

  more particularly the use of probes in automatic machine tools intended to come into contact with the part and provide information relating to it. Automatic machine tool systems require a precise means of positioning the surface of the parts. One of the most common methods consists in making the machine move a probe to bring it into contact with the part and to record its position. when contact occurs Probes of this type are called contact probes They generally include a style intended to come into contact with the part and a circuit which produces an electrical signal when style 15 is in contact with the part The machine controller can calculate information about the shape or location of the part in a coordinate system with three axes, X, Y and Z when the contact of the style produces the

electrical signal.

  One of the problems encountered during 2.

  using one of these types of welding systems is the method by which the signal indicating contact due to the probe is returned to the controller.

  It is often inconvenient to rely on conventional wiring 3 to route the signal because wires can interfere with

normal machining operations.

  The patent literature describes several probe systems which are intended for use in an automatic machining center where the probes are temporarily stored in a tool magazine, then plugged in and removed from the spindle by an automatic change mechanism Tool Representative examples of patents describing these probes include US Pat. Nos. 4,339,714 (on behalf of Ellis); 15 na 4,118,871 (in the name of Kirkham) and United States patent application no. 259,257 entitled: "Apparatus For Detecting The Position Of A Probe Relative

  To A Workpiece "filed April 30, 1981 (on behalf of Juengel).

  Kirkham's solution has the disadvantage that its high frequency signals are susceptible to electromagnetic interference and must be used with relatively short transmission distances between the probe and a receiver. Among the problems raised by the probe system of the Ellis patent, it extreme care must be taken in aligning the probe and a special construction detector mounted on the spindle head so that the reactive coupling obtained functions correctly The solution with infrared transmission, described in the Juengel patent, is by far the most interesting However, it requires that the probe, in the

  in most cases, contains its own power source.

  It has been proposed to use probes in turning centers such as lathes, as well as in machining centers. Turning centers are different from machining or milling centers in that the workpiece rotates. in place of the tool In most turning centers, the tool holders are mounted in spaced locations from each other around a turret which operates so as to selectively advance one of the tools towards the workpiece so that the machining is carried out In general, the tools making it possible to carry out operations concerning the external dimensions of the part are mounted in notches made in the turret whereas the tools machining the internal dimensions, for example in the bore of the bars, are held in a

adapter mounted on the turret.

  Contact probes used in turning centers raise a somewhat different set of problems than those encountered in machining centers, although the method of transmitting the signal from the probe to return it to the controller remains A common concern One of the problems pertaining only to turning centers is that the probes remain fixed to the turret even when they are no longer needed, unlike in the case of machining centers where the probes do not are inserted into the spindle as needed. Therefore, it is not possible to rely on the probe insertion operation to actuate the electronic circuit it contains. A prior art contact probe technique for turning centers uses induction transmission modules to transmit the signal from the probe, via the turret, to the controller. We will see on this subject, for example, the literature concerning the probe system known as LP 2 from the company known as Renischaw Electrical Limited Unfortunately, this technique requires a significant modification of the turret to allow the use of the system Consequently, the use of this solution is not easy in existing machines 35 because it requires costs and some downtime

  for the execution of the adaptation operation.

  4. Also related to the present invention, although less directly, is the prior art relating to the wireless transmission of dimension measurement data, such as

  this is described, for example, in US Patents 3,670,243, 4,130,941 and 4,328,623.

  The subject of the present invention is a device and a method for performing part probing operations so as to extend the life of the energy supply sources, which are used in these types of probe. embodiment of the present invention, the probe comprises a detector which is used to connect the power source to the signal transmission circuit of the probe when the detector receives a given signal Des

  Means are provided which are located at a certain distance from the probe to produce this "on" signal and wirelessly transmit the signal to the detector placed in the probe.

  This signal is produced before the intended use of the probe to inspect the workpiece and can be caused by the controller of an automatic machine tool. Then, the power source is disconnected. Energy is only supplied by the source when this is necessary This solution is particularly advantageous when probes are used in turning centers where they remain fixed to the turret, although they are not always used for inspection operations However the general concepts of the present invention can be applied to a wide range of other survey systems

and machine tools.

  In the preferred embodiment of the invention, the controller of the machine causes a flash of infrared radiation from a head mounted in a convenient location of the machine. As a result, the transmission circuit of the probe is validated. and produces an IR signal at a given frequency to indicate that the son'5 is working properly and is ready for use The controller then proceeds to the inspection operation When 5. the style of the probe is in contact with there is a shift in the frequency of the IR transmission. This frequency shift is detected remotely and used by the controller to obtain useful information on the piece. The probe circuit preferably includes a timer which cuts the supply of circuit components after a predetermined next period of time

  power up or style contact with the room.

  Advantageously, the head can assume the dual function of transmitting the lightning trigger signal and of receiving IR radiation coming from the probe. The head comprises an interior device producing flashes and a photodetector. An external face of the housing of the head. preferably includes a lens 15 with an IR filter The IR filter is used to filter light in the visible spectrum of lightning during the period of operation of the probe The lens is used to focus

  IR radiation from the probe on the photodetector mounted in the head.

  In another embodiment, the power supply to the probe circuit is applied initially when the style is in contact with a reference surface. During operation, the machine moves the probe so that the style comes into play. contact with the reference surface to cause an active cycle The probe is then used to inspect the part, the probe only working to send signals concerning the latter to

  a receiving head located at a distance.

  The present invention will be understood from the following description given in conjunction with the accompanying drawings in which:

  Figure 1 is a view of an environment showing a sounding system according to the techniques of the present invention when used in an automatic machine tool; 6. Figure 2 is a perspective view of a sounding system using the lightning trigger technique according to an embodiment of the present invention; Figure 3 is a perspective view of the use of a sounding system with the contact triggering technique according to a variant of the embodiment of the invention; Figure 4 shows a sectional view; taken 11 l along line 4-4 of Figure 2, of a probe construction according to an embodiment of the present invention; Figure 5 is a sectional view taken along line 5-5 of Figure 4; Figure 6 is an exploded perspective view of the probe shown in Figure 4; Figure 7 is a perspective view of a lightning / receiving head used in an embodiment of the present invention; Figure 8 is a sectional view taken along line 8-8 of Figure 7; Figure 9 is a top plan view of a circuit board used in the head of Figure 7; Figure 10 is a circuit diagram used in the lightning / receiving head; Figure 11 is a circuit diagram used in the probe of an embodiment of the present invention employing the flash trigger technique; and Figure 12 is a circuit diagram used in a probe employing the contact trigger technique. FIG. 1 represents, in simplified form, a typical machine tool machine system using the various aspects of the characteristics of the present invention. A numerically controlled turning center 10 is 7. represented with a controller 12 for the automatic control of the turning operations on a workpiece 14 according to programmed instructions The turning center 10 typically comprises a rotating mandrel 16 with jaws 18 making it possible to hold the workpiece 14 Mounted on a turret 20, a plurality of tools 22 24 execute operations concerning the internal dimensions of the workpiece 14 Typically, tools of this type comprising an elongated shank which is held in place in the turret 20 by means of adapters 26 28 According to the present invention, a workpiece inspection probe 30 is mounted

  on the turret 20 in the same way as the tools 22 24.

  In this embodiment, the probe 30 is mounted on

  the turret 20 by means of an adapter 32 identical to the 15 adapters 26 28.

  As is known in the art, the controller 12, among other functions, causes the turret 20 to rotate and brings the desired tool to the appropriate working position, then moves the turret 20 until 1 'or 20 it comes into contact with the part and executes its machining operation. The probe 30, on the other hand, is used to inspect the part 14. In this specific example, the probe 30 is known in the industry under the name of probe to contact, in the sense that it produces an output signal when its style comes into contact with a surface of the room or other object. Appropriate resolvers, digitizers, or the like serve to supply signals to the controller 12 indicating the position of the probe 30 Consequently, when the signal coming from the probe 30 indicates that there is contact with the part, the controller 12 can draw useful information on the dimensions of the part, on its position inside chuck etc.

  The probe 30 contains its own energy source 35 to supply its signal transmission circuit.

  8. Unfortunately, the energy source, in this case batteries, has a limited lifespan. Thus, there is a real need for a means allowing the prolongation of the lifespan of batteries as much as possible. especially true for small probes that are used in turning centers Small probes can only use small batteries, and therefore it is very important to

move to conserve energy.

  In one of its aspects, the present invention provides for bidirectional optical communication between the probe 30 and a lightning / receiving head 40 The head 40 is connected to the controller 12 via an interface 42 When the controller 12 determines that the probe 30 should be used for a probing operation, it produces a signal on a line 44 connected to the interface 42, which in turn generates a control signal on a line 46 so that the head 40 transmits an optical signal given to the probe 30 In the preferred embodiment, this optical signal is a flash with a high density of infrared radiation This flash is detected by an appropriate sensor 48 mounted in the probe 30 (see FIG. 2) L lightning causes the detector to couple the batteries to the probe transmission circuit Preferably, the probe 30 responds to lightning by transmitting IR radiation at a given frequency to return it to the head 40, via electrolytic diodes uminescent 50 54 This infrared radiation is received by the head 40 which in turn provides a signal to the controller 12 via the interface 42, 30 indicating that the probe 30 is functioning correctly and is

  ready to execute its inspection operation.

  The controller 12 then causes the turret 20 to advance until the style 56 of the probe 30 comes into contact with the part 14. The probe 30 responds to this style contact by creating an offset of the frequency 9. of the IR radiation transmitted by the diodes 50-54 The frequency offset is detected by the interface 42 and communicated to the controller 12 The operation of inspecting the part continues, if necessary, with the probe 30 transmitsD both the radiation IR frequency offset at head 40

  whenever the style makes contact.

  The probe 30 includes a timer means which disconnects the batteries from the transmission circuit after a predetermined period of time. This period of time begins when the battery voltage is initially applied to the circuit and starts again each time the style comes into contact with the part. Thus, at the end of the probing operation, the period of time ends and the batteries are disconnected from the transmission circuit Consequently, the batteries are only used during the periods of expected use of the probe Each time the probe is not in use, the batteries are not used, which

  extends their lifespan.

  FIG. 3 represents another embodiment making it possible to extend the life of the batteries.

  In this example, the batteries are first connected to the probe transmission circuit by bringing style 56 into contact with a known reference surface 60 The surface can be any fixed point of the machine 10, 25 of which location is known to the controller 12 The contact of the probe with the surface 60 has the effect of coupling the batteries to the transmission circuit of the probe and of starting the transmission by light-emitting diodes 50-54 to the head 40 'The head 40' is identical to the head 40 previously described except except that it does not require any means of lightning formation, just as the probe 30 'does not require any photodetector 48 Furthermore, the two embodiments function in a substantially identical After initialization, the probe is brought into position to inspect the part 14, with the probe 30 'transmitting to the head 10.' signals shifted in frequency each time the contact is made in the style After a lap s for a predetermined time after the last contact made by the style, the batteries are disconnected from the probe's transmission circuit. Figures 4-6 show in more detail the construction of the probe 30 The housing of the probe is characterized by a middle part 70 having the general shape of a cone and a tail 72 projecting rearward, or 10 part cylindrical with a reduced cross-sectional diameter In this specific embodiment, the cylindrical part 72 is hollow, measuring approximately 10 cm long, with a diameter

outside about 3.5 cm.

  The external dimensions of the cylindrical part 72 15 are chosen so as to generally correspond to the dimensions of the body or the shank of the tools 22-24 Consequently, the probe 30 can be mounted in place of one of the tools in the turret 20 and hold it in the adapter 32 in the same way As shown more clearly in FIG. 4, this can be carried out by sliding the cylindrical part 72 in the hollow part 74 of the adapter 32 until the wall rear 76 of the part 70 of the casing abuts against the front face 78 of the adapter 32 This operating mode thus makes it possible to place the tip 25 of style 56 at a known distance from the turret 20 Consequently, the controller 12 can rely on style 56 position during probe inspection operation Of course, other conventional means can be used to position style tip 56 at the appropriate distance. For example, some machine tool systems use a screw pressure (not shown) or some other means in

  the rear part of the hollow part 74 to adjust the position of the style.

  The cylindrical part 72 advantageously provides a battery compartment and an easy-to-use mounting element 11. The elongated cylindrical shape of the part 72 makes it possible to use for the supply of the probe transmission circuit the "cylindrical" batteries used in typical flashlights Preferably, two lithium batteries 80, 82 are used. The possibility of using cylindrical batteries instead of small batteries, such as buttons or discs, results in the probe having long running life

Low cost.

  The batteries 80, 82 are slid inside the part 72 A cover 84 subjected to the action of a spring is then screwed on the end of the part 72, the spring 86 urging the positive terminal 88 against a plate with circuits 90 The internal surface of the plate 15 te 90 comprises a circular conductive layer 92 The plate 90 is fixed inside a cavity 94 formed in the internal surface of the wall 76 by means of screws 96 An insulated wire 98 makes the electrical connection with the conductive layer 92 by means of coated through holes 20 which are made in the plate 90 The opposite end of the wire 98 is connected to a circuit board

  containing the probe circuit A description of the

  electrical circuit diagram will be made later.

  The circuit board 100 generally has a cylindrical shape, containing electrical components which are mounted on its two sides. The board 100 is mounted inside the middle part 70 by means of suitable fasteners 102 passing through a barrel 104 La wafer 100 also includes a central opening 106 that traver30 feels various wires to facilitate connection to certain

  appropriate places on this plate.

  The photodetector 48 and its associated sub-assembly are mounted in the inclined outer surface 110 of the central part 70 of the casing. The photodetector 48, in this particular example, is a diode called PIN such

  component n DP 104 from the company known as Telefunken.

  12. The photodetector 48 is mounted in a bore and is held in place by a cover 112 comprising a window Interposed between the cover 112 and the photodetector 48 are a transparent plastic material 114, an infrared filter 116 and an O-ring 118 all in the form of a layer Appropriate fasteners fix all these components in a sub-assembly mounted inside the bore The wires of the photodetector 48

  pass through the opening 106 and are connected to points ap10 of the wafer 100.

  The light-emitting diodes 50-54 are mounted at a location contiguous to the photodetector 48. They are designed so as to emit optical signals in the band of infrared radiation, that is to say a light which is not normally visible for the human eye Diodes 50-54 can be, for example, component no. 0 P 290 from the company known as TRW, Inc. It will be noted at this stage that the arrangement of diodes 50-54 and of photodetector 48 on the inclined surface of the probe has several important advantages For example, by mounting the diodes 5054 on the inclined surface 110 of the probe, the infrared radiation thus emitted is directed at the front of the turret at an angle which allows easy capture of the radiation to the various head locations 40 The construction of the probe allows the user to rotate it to a position where the diodes 50 54

  and the photodetector 48 are directed towards the head 40.

  Thus, it is not necessary to mount the head 40 at an absolute spatial location relative to the probe 30, giving the system great flexibility for its use in different machine tool systems. Reliable optical communication between the probe 30 and the head 40 is therefore obtained, while having a minimization of the number of light-emitting devices mounted inside the probe. Keeping the number of the 13. light-emitting devices at a minimum value,

  the energy consumption of the batteries is made as low as possible, which prolongs their service life.

  At the periphery of the middle part 70, the wall 76 is fixed to the rear portions of this part by means of appropriate fasteners 122 O-rings, such as

  the seal 124, are advantageously used to seal the interior of the probe 30 against somewhat hostile conditions that the probe may encounter during its use in a machine tool system.

  An angular nose 130 comprises a male threaded element 132 which is screwed onto the threads formed in a bore 134 of the front face of the middle part 70 An O-ring 136 is again used there for sealing purposes The nose 130 may have different lengths so as to modify the position of the tip 56 of the style, if necessary thanks to the screwing on the middle part 70

  of the housing, various noses can be used and interchanged to meet different applications.

  A switching assembly 140 is removably attached to the nose 130 The assembly 140 comprises an extreme circular part 142 provided with a groove comprising an O-ring 144 which is mounted according to a tight fit in the internal channel 146 of the nose 130 One or several pressure screws 148 extending perpendicularly to the nose to fix the assembly in place 140 The switching assembly 140 can be of various types making it possible to open or close one or more electrical contacts which it contains when the style 56 leaves its rest position Those skilled in the art know various constructions of this

  type satisfying this general object A suitable construction of a switch is described in detail in United States patent application No. 388,187 filed June 14, 1982. This patent is assumed to be known here.

  In short, this construction employs an oscillating plate 14. comprising three contacts per ball situated at equal distance from each other. The plate is biased by a spring so that the balls are normally pressed against three corresponding added elements which conduct electricity. The three ball-insert pairs act as a switch (hereinafter referred to as switches 51-53) and are connected in series The oscillating plate is connected to style 56 Each time style 56 moves, the plate switches and moves a ball away

  1 C of its corresponding insert, which has the effect of breaking the electrical connection.

  The three switches mounted in the assembly 140 are connected to the circuit of the wafer 100 by means of a cable 150 The other end of the cable 150 comprises a miniature coaxial connector 152, or other suitable connector, which couples with a connector mounted on the end of the assembly 140 Those skilled in the art will note that these types of switching assemblies are very sensitive and that they may have to be replaced The construction of the present invention makes it possible to carry out quickly and easily such a replacement. Various styles shapes and sizes can be used in conjunction with the probe 30 For example, instead of the straight style 56 shown in the figures, a style may be employed in which the tip is offset from the main longitudinal axis of the 30 probe

  various styles are interchangeable in the switch assembly 140 and can be fixed thereto by suitable securing means, for example by pressure screws.

  The mechanical details of the lightning / receiving head 40 are shown more clearly in FIGS. 7 to 9 The head 40 uses a generally rectangular container 160 which has an opening 162 in its front face 164 One or more circuit boards 166 are 15. mounted inside the container 160 The wafer 166 comprises various electrical components which execute

  functions which will be described later in detail.

  Two of the most important components are represented in these figures. It is a xenon flash tube 168 and a photodetector 170 As mentioned previously, the function of tube 168 is to produce a pulse of high intensity light, short-term, intended to initiate the operation of the probe Xenon is preferred 10 because it produces light rich in infrared radiation In the preferred embodiment, the flash tube 168 is the xenon flash tube called BUB 0641 of the so-called Siemens company It can produce a flash or pulse of light lasting approximately 50 microseconds with an intensity of 100 watt / second Other types of light sources

  appropriate can of course be used.

  Although it is not absolutely necessary, the visible light produced by the flash tube 168 is preferably eliminated so as not to attract the attention of the operator or other persons of the workshop or the machine tool. is used For this purpose, an infrared filter 172 covers the opening 162 The filter 172 is used to stop

  visible light but lets pass the infrared radiation produced by the tube 168.

  The function of the photodetector 170 is, on the other hand, to detect the infrared radiation transmitted by the probe 30 In this embodiment, the photodetector is a so-called PIN diode and operates in the same way as the photodetector 48 of the probe 30 A 3 C convex lens 174 is advantageously used in the aperture 162 to concentrate the IR radiation coming from the probe 30 on the photodetector 170 which is located at the focal point of this lens On the head 40 is mounted a transparent face plate 176 The plate 176 covers the opening 35 162 and is suitably fixed to the face 164 by 16.

through a seal 178.

  FIG. 10 represents the circuit used in the lightning / receiving head 40 of the preferred embodiment of the invention. As mentioned previously, the head 40 is coupled to the interface 42 by one or more

  several lines represented by the reference 46.

  A 26 volt AC signal

  is applied to the primary of a step-up transformer T 1.

  The energy of the transformer T 1 is stored in capacitors C 8 and C 9 which are in turn coupled to the positive and negative electrodes of the xenon flash tube 168 In this embodiment, the capacitors C 8 and C 9 have

  a voltage of about 250-300 volts direct current when fully charged.

  To cause a flash through the tube 168, the controller 12, via the interface 42, produces a signal of appropriate level on the lines called "control" to cause a light-emitting diode 171 to be conductive and to emit light The diode 171 is part of an optical isolation assembly, containing a controlled silicon rectifier 173 The rectifier 173 is connected in series with the primary of a transformer T 2 and with a capacitor Cl O The capacitor C 10, like the capacitors C 8 and C 9, is charged by switching on the transformer T 1. 25 When the light-emitting diode 171 is activated, the diode 173 is conductive and causes the discharge of the capacitor Cl O in the primary of the transformer T 2 This charge is carried at around 4000 volts by the transformer T 2, the secondary of which is connected to the triggering electrode 175 of the flash tube-168 The electrode 175 forms a capacitive coupling with the tube 178 and the high voltage is known ffisante to ionize the gas inside the tube The ionized gas is sufficiently conductive to allow the energy of the capacitors C 8 and C 9 to discharge in the positive and negative electrodes and create a flash of very high intensity and short-lived After the production of

  lightning through the tube 168, the capacitors start to recharge until another lightning strike control signal is supplied by the interface 42.

  The probe 30 responds to lightning by transmitting the IR signal which is picked up by the photodetector 170 of the head 40 The photodetector 170 is coupled to a tuned plug circuit, consisting of a variable inductor L1 and a capacitor C 2 A As a specific example, probe 30 will produce pulsed IR radiation at a frequency of about 150 kilohertz until the style of the probe comes into contact with an object, at which time the frequency will drop to about 138 kilohertz. cap mounted in head 40 is tuned to approximately 15 the average of these two frequencies, so the head circuit can detect either of these probe frequencies but will filter out foreign frequencies within outside a selected range or bandwidth. The rest of the circuit of Figure 10 is used to amplify the detected signal, transmitted from the probe 30 which is coupled by the "output" line to the interface 42 In short, the head amplification circuit employs a field effect transistor Q 1 whose high input impedance is matched to that of the tuned circuit so as to avoid load problems The transistor Q 2 in cooperation with the transistor Q 1 amplifies the received signal and applies it to an emitter follower employing a transistor Q 3 The amplified signal is coupled to the inter30 face 42 by the output line via a

  capacitor C 6 and a resistor R 7 of a DC filter coupled to the emitter of transistor Q 3.

  The interface 42 includes a circuit which detects these frequencies of the signal from the probe and produces outputs which are applied to the controller 12 18. in response A first signal is produced to indicate that the probe is working correctly and a second signal when the style of the probe is in contact with an object A suitable circuit allowing the detection of the frequency offset is described in the patent application of the United States of America n 414 734, filed on September 3, 1982 and having for title : "Machine System Using Infrared Telemetering" It will be assumed here that this request is known. In short, such a circuit employs a phase-locked loop circuit 10 to execute a frequency shift operation on the received signals and

  actuates relays upon detection of one or other of the selected frequencies However, various other methods of detecting probe signals will be understood by those skilled in the art.

  FIG. 11 represents an electrical diagram mounted inside the probe 30. A Ql O transistor of the PNP type operates as a switch to selectively connect or disconnect the batteries 80, 82 of the components used so that the light-emitting diodes 50-54 produce the IR radiation The transistor Ql O is normally in the non-conducting state; therefore, batteries 80, 82 effectively see an open circuit so that there is no consumption of the energy of these batteries However, when the head 40 produces its flash of IR radiation, the photodetector 48 conducts the current from the batteries to pass through an inductor L1 for the duration of the flash. The very fast rise time associated with the light pulse from the xenon flash tube provides a unique signal which can be easily discriminated from

  other light sources in the machine tool area.

  The IR filter of the head 40 excludes most of the visible spectrum so that the lightning cannot be seen and disturb the people in the vicinity When the light pulse 19. reaches the photodetector 48, it is transformed into an electric pulse at the inductor terminals L 10 The coil L1 O serves as a high-pass filter and excludes light pulses in the constant state or at low frequency such as fluorescent light as the area

  where the machine tool can be found.

  The current peak passing through the photodetector 48 during the flash creates a "ringing" phenomenon

  in the inductor L 10, as is known in the art. 10 This phenomenon is basically a damped oscillation which lasts for around 500 microseconds in response to the light pulse from lightning of around 50 microseconds.

  The oscillations of the inductor L 1 are amplified and inverted by an inverting amplifier 200 The output of the amplifier 200 is connected to the base of the transistor Q 10 The momentary "ringing" of the inductor LI due to the lightning causes a direct polarization of the base-emitter junction of the transistor Q 10 and makes it conductive The conduction of the transistor Q 10 results in the application 20 of the voltage of the batteries 80, 82 to the power inputs of the components of the circuit having for reference + V in the figures When the voltage is applied to the oscillator 202, it begins to supply pulses to an elapsed time counter 204 The counter 204 is reset to zero to initialize its counting of the elapsed time when the head 40 receives the lightning is executed by means of an inverter 206 which inverts the output of amplifier 200 to give a positive signal which is impulse shaped by the time constant RC of a capacitor C 20 and a resistor R 2 0 This pulse is applied to the reset input of counter 204 via an OR gate 208 As will appear, the elapsed time counter 204 is also reset whenever style 56 of the probe comes into contact with an object, which is reflected by opening 20.

from one of the Sl-53 switches.

  Counter 204 is designed to provide a low logic level signal on its output line 210 when

  counts, that is to say when the time has not expired.

  The low logic level signal from line 210 is inverted by an inverter 212 which in turn is connected via a diode D 20 to the input of amplifier 200 As a result, the output of the amplifier goes to a low level, which has the effect of keeping the transistor Q 10 in the conducting state, supplying energy to the components of the circuit until the counting of the counter ends 204 The counting duration of the counter 204

  is chosen so as to be long enough to allow the controller 12 to start the actual inspection process, with the style of the probe in contact with the part.

  In general, a duration of several minutes is sufficient.

  The counting time can be adjusted by means of a potentiometer P 20 defining the oscillation frequency of the oscillator 202 Higher frequencies of the oscillator 202 cause a faster counting of the counter 204 and therefore, the cessation of its operation in a shorter time and vice versa The generation of delays

  is naturally well known to those skilled in the art.

  A carrier oscillator 220 and a divider 222 25 cooperate to define the frequency at which the light-emitting diodes 50-54 return the IR radiation to the head 40 Conventionally, the oscillator 220 uses a quartz 224 having a resonance frequency known as master watchmaker L oscillator 220 shapes the oscillations of quartz 224 to give them a shape for supplying clock pulses to a conventional digital divider, such as divider 222 divider 222 serves as a convenient means of shifting the frequency transmitted by the diodes 50-54 when the style of the probe is in contact with an object. In this particular example, the divider 222 operates so as to divide the pulses 21. of 1.8 M Hz coming from the oscillator 222 by 12 and therefore provides

  at its output signal frequencies of about 150 K Hz.

  The output of the divider 222 is coupled to a driving transistor Q 12 or other suitable circuit making it possible to atact the diodes 50-54 at the frequency defined by the output of the divider. Thus, in this example, when the head 40 starts the sequence of production of a flash, the probe responds by starting the transmission of IR radiation at a given frequency The transmission of the probe is detected by the photodetector 170 mounted in the head 40 which, in turn, provides an indication to the controller 12 that probe 30 is working properly and is ready to start the probing sequence If probe 30 does not respond

  in this way, precautionary measures can be taken.

  When the style 56 of the probe is in contact with an object, one of the three switches Sl-53 of the set 140 will open The opening of one of the switches 51-53 does two things First of all , the counter 204 20 is reset to the beginning of its elapsed time counting sequence Secondly, it creates an offset of the frequency transmitted by the diodes 50 54 This can be accomplished in various ways However, in the preferred embodiment, the opening of one of the switches S 1 53 causes a comparator 228 to go high. The output of the comparator 228 is coupled to the reset input of the counter 204 via an OR gate 208 and thus resets the counter to zero In addition, the output of the comparator 228 is coupled to an input for manipulating the frequency offset of the divider 222 by a line 229 to cause it to divide the clock pulses coming from the oscillator carrier 220, by a different number in the present case nt by the number 13 The output signals of the divider 222 thus change frequency to have a frequency of approximately 138 K Hz Thus the frequency es 4 22. of the IR radiation transmitted by the diodes 50-54 is offset with respect to the frequency transmitted when the probe was originally started This frequency offset is detected by the photodetector 170 and transmitted to the controller 112 so as to indicate the contact of the style with an object, normally with the surface of a room

  The controller 12 knowing the position of the style 56 when this signal is received can accurately calculate the dimensions of the room or give any other useful information.

  The controller 12 can cause the displacement of

  the probe 30 to bring it into contact with other surfaces of the room, each time the probe responds by an offset in the IR radiation transmitted from the probe.

  The elapsed time counted by the counter 204 is chosen so as to be greater than the time which would elapse between contacts of the style When the sounding operation is finished, the controller 12 can go ahead with other operations machining, if necessary It is not necessary to produce other signals to deactivate the probe, because the batteries will be automatically disconnected as soon as the counter has reached the counting of the expected elapsed time In this case, its line output 210 goes high, which ultimately results in a reverse polarization of the base / emitter junction of the transistor Ql O This has the effect of putting the transistor Q 10 in the nonconductive state In this way the only current extracted from the batteries 80, 82 is the leakage current of the semiconductors and the photocurrent of the photodetector 48 Typically, this current can be very small, often less than 300 microamperes Consequently, the largest components cons Energy monitors are disconnected from the batteries until they are actually needed for the expected use of the probe. Preferably, these components 35 consist of CMOS semiconductors (semiconductor

2,548,349

  23. oxide-metal with complementary symmetry) so as to preserve

  even more battery power.

  By way of nonlimiting example, the carrier oscillator 220 consists of the transistor controlled by quartz known as n 2 N 2222, the divider 222 of the component known as LM 4526 from the company known as National Semiconductor, the oscillator 202 by one half of integrated circuit known as LM 2903 of the company National Semiconducteur, and the counter 204 of

  component LM 4040 from the company National Semiconducteur.

  The contact start-up technique described above in connection with FIG. 3 can be used as a variant of the lightning start-up technique described above. The two techniques have the same general objective, that is to say to increase the lifetime of the batteries To a large extent, the construction of the probe and the circuit of the two techniques are similar. A diagram of the circuit of the probe for the contact start-up technique is represented in FIG.

  circuit is identical to that of circuit 11, the same reference numbers 20 will therefore be used for identical components.

  The comparison of the two figures shows that the important difference is the elimination of the photodetector 48 and its associated inductor L 10 in favor of a resistance R 50 and a capacitor C 50 This circuit is also different in that it includes a line 231 connected between the switches 51 53 of the probe and a node N 1 coupled to the input of the inversion amplifier 200 The transistor Q 10 is kept in the non-conducting state until 30 o one of the switches 51-53 opens following the coming into contact of the style 56 with a reference surface 60 (Figure 3) This is due to the fact that the switches Sl-53 maintain the input of the amplifier 200 substantially at ground level as long as they are closed, that is to say when the style of the probe is not in contact 24. with anything However, when the style 56 is in contact with the reference surface 60, one of the switches 51-53 opens and initiates the charging of a capacitor C 50 Preferably, the value of resistors R 50 and R 18 as well as of capacitor C 50 is chosen so as to obtain a time constant RC which delays the moment when capacitor C 50 is charged at a voltage sufficient to make conductive the transistor Q 10 l after inversion by the amplifier 200 This necessitates the maintenance by the controller 12 of the style 56 against the reference surface 60 for a defined time, for example approximately one second This operating mode will ensure that

  accidental shocks to the probe style or other external factors such as electrical noise will not inadvertently cause the probe to operate.

  As soon as the capacitor C 50 has been sufficiently charged, the transistor Ql O becomes conductive and the voltage of the batteries 80, 82 will be applied to the transmission components of the probe. The counter 204 will be reset to zero and will supply its output signal by the line 210 so as to pass the transistor Q1 O to the conducting state In this embodiment, the divider will cause the generation of the lower of the two output frequencies due to the triggering of the comparator 228, when the style 56 is in contact with the reference surface However, the controller 12 can be suitably programmed to consider this initial signal from the probe as an indication that the probe has been correctly turned on and is ready to proceed with the inspection of the part. 30 The controller 12, knowing that the probe 30 'is functioning correctly, then moves over the part for its inspection with the style 56 in contact with various surfaces of this part As soon as the style 56 has moved away from the reference surface 60 , the switches 51-53 close, causing the divider 222 to attack the light-emitting diodes 25. 50 54 at the other frequency As soon as the style is in contact with a surface of the niece, one of the switches Si 53 s opens again, triggering the comparator 228 This results in the resetting of the counter 204 The triggering of the comparator 28 also provides an output on the line 229 so that the divider 222 changes its frequency and consequently that of the diode outputs 50 54 This process continues until the part 10 inspection process is completed, the batteries being automatically disconnected from the probe circuit as soon as the timer 204

  comes to the end of its counting time.

  The present invention is not limited to the embodiments which have just been described, it is on the contrary subject to modifications and variants.

  which will appear to those skilled in the art.

26.

Claims (18)

  1 Device intended for use in a machine tool system comprising: a first means for detecting information on a workpiece, this first means comprising a circuit means for transmitting information concerning the workpiece to a remote receiver, a source of energy, and a detector means operable to apply energy from the source to the circuit and allow it to operate upon receipt of a given signal and second means located remote from the first means for wireless transmission the signal given by the detector and thus initiating the supply of energy to the cooked circuit; from which it follows that the energy extracted from the source is minimized by selectively using the energy   coming only during the expected periods of use.   2 Device according to claim 1, o the circuit means comprises a timer means for stopping   the supply of energy by the source to the circuit after the expiration of a predetermined period of time.   3 Device according to claim 2, o the predetermined period of time is measured from the time at which the energy from the source is initially supplied to the circuit or from an indication that the first means has effected a detection operation.   4 Device intended to be used in a machine tool system in order to detect the contact with a part comprising: a probe means comprising a style intended to come into contact with the part, a circuit means for transmitting information wirelessly associated with styling contact with a remote receiver, a battery power source 27., and photodetector means operable to apply energy from the batteries to the circuit and allow it to operate upon receipt of a optical signal given; and a first means located at a distance from the probe for transmitting the optical signal given by means of the photodetector of the probe before its expected use, from which it results   that the energy required from the batteries is minimized.   Device according to claim 4, in which the cooked ciro 10 of the probe comprises a timer which stops the supply of energy by the batteries after a predetermined period of time has elapsed since the generation of the given signal or the coming into contact. style with the room.   6 Device according to claim 5, o the given optical signal is a flash with high intensity of infrared radiation.   7 Device according to claim 4, o the probe further comprises: an optical transmission means connected to the means   circuit, capable of operating to transmit infrared signals that indicate style contact with the room.   8 Device according to claim 4, o the first means further comprises: a housing containing a flash tube, a photodetector and an infrared filter covering an opening   practiced in a wall of the casing.   9 Device according to claim 8, o the housing further comprises a lens for focusing the IR ray30 ment from the probe on the photodetector.   Device according to claim 7, where the probe circuit can operate to generate a given frequency in order to attack the optical transmission devices when the battery energy is applied first, and to shift the frequency when the style 28. is in contact with the part.   11 Method of using a battery-powered probe in a machine tool system, characterized in that it comprises: producing an optical signal before the expected use of the probe; detecting the signal to the probe, and using the detected signal to apply battery power to electrical components located inside the probe for a time sufficient to allow the probe to perform the desired operations on a coin.   12 The method according to claim ll, characterized in that it further comprises the following steps: the transmission of an optical signal of a given frequency from the probe when the energy of the batteries is initially applied to the components of the circuit; and   the offset of the frequency of the optical signal 20 transmitted when the probe is in contact with the part.   13 Method according to claim 11, characterized in that it further comprises the step of: -cessation of the supply of energy by the batteries to the components of the circuit after a predetermined period of time has elapsed since detection of the optical signal or of the coming of the probe in contact with the room.   14 Probe for the detection of information on a part, characterized in that it comprises: a circuit means for the wireless transmission of information on the part detected to a receiver located at a distance; a battery power source; a detector means capable of operating to initiate the supply of energy by the batteries, by means of circuit 35 and to allow operation thereof when a 29 is received. signal given, transmitted wirelessly.   A probe according to claim 13, where the means   detector is a photodetector operating to respond to a given optical signal.   16 A probe according to claim 14, o the optical signal given is a flash of high intensity of infrared radiation. 17 A device for use in a sounding system used by a machine tool, comprising: a container comprising a light source and a photodetector, means for exciting the light source before the sounding operation, and means coupled to the photodetector for detecting receiving optical signals containing information about the sounding operation. 15 18 Device according to claim 16, characterized in that the light source is a flash tube; the photodetector responds to infrared radiation; and the   container has an infrared filter to sensibllement filter light from the visible spectrum produced by the flash tube.   19 Device according to claim 16, o the   The container further comprises lens means for focusing the optical signals on the photodetector.   Method for using a battery-powered probe in a machine tool system, characterized in that it comprises: bringing the probe into contact with a reference surface and applying the energy of the batteries to electrical components located inside the probe 30 in response to this contact; the use of the probe to detect information on a part; and the cessation of energy supply for   batteries after the expiration of a predetermined time 35.   30. The method of claim 20, further comprising the step of: wireless transmission to a receiver located at   distance of information on the detected part.   22 Input circuit means in a probe used for the detection of information on a part, the probe comprising at least one optical transmission device for transmitting information to a receiver located at a distance, electrical components for controlling 10 optical device, at least one battery for supplying energy to the components, characterized in that it contains a photodetector and an inductor coupled to the battery, capable of operating to produce an output signal of a given amplitude in response to a lightning bolt produced remotely, and switch means responsive to the output signal for applying battery power to electrical components and allowing optical transmission of information to the receiver located remotely.   23 The circuit means of claim 22, which further comprises: timer means for producing a trigger signal to maintain the switch means in a given state and thereby maintain the connection of the battery for a predetermined period of time ; first means for detecting when the probe is in contact with an object; second means for producing at least two different frequencies for driving the optical transmission means; and the first means being connected by means of   timer and the second means operable to reset the timer and create a frequency offset when the probe is in contact with an object.   24 Probe for detecting information 31. on a part, the probe having at least one optical transmission device for transmitting information to a receiver located at a distance, electrical components to attack the optical device and at least a battery for supplying energy to the components, characterized by: switch means for selectively applying energy from the battery to the components according to their state; and input circuit means responsive to contact of the probe with an object to produce a signal   sufficient to cause a change in the switch means and apply battery power to the components.   Probe according to claim 24, o it comprises at least one normally closed contact which opens when it comes into contact with an object, and o the input circuit comprises a capacitor means coupled to the battery and to the contact, capable of operate to store energy from the battery when the con20 tact is open and generate an output signal of sufficient amplitude after a predetermined amount of time to   change the state of the switch means.   The probe of claim 25, which further comprises: timer means for producing a trigger signal to maintain the switch means in the state of maintaining the connection of the battery with the components for a predetermined period of time ; first means for detecting when the probe is in contact with an object; second means for producing at least two different frequencies to drive the optical transmission device; and the first means being connected by means of 32.   timer and the second means operable to reset the timer and create a frequency offset when the probe is in contact with an object.