JPS6013202A - Method and device for inspecting work by using probe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to workpiece inspection systems, and more particularly to the use of probes in automatic machine tools to contact a workpiece and provide information about the workpiece.

Automated machine tools require sophisticated equipment to position the workpiece surface. One of the most common methods is to have a machine tool contact a probe with the workpiece and record the position of the probe when contact is made. This type of probe is designated as a contact probe. These probes generally include a protrusion that contacts the workpiece and a circuit operative to produce an electrical signal when the protrusion makes contact with a predetermined part. Information about the shape or position of the part can be calculated from the X, Y and Z axis position data of the probe when the contact produces an electrical signal.

One of the problems encountered in many uses of these types of inspection systems lies in the manner in which the signals indicative of contact by the probe are sent to the controller. This method is often impractical to rely on traditional wires to transmit signals because the wires can interfere with normal processing operations.

The patent literature discloses several probe configurations for use in automatic processing centers where the probe is temporarily stored in a tool magazine and loaded and unloaded with respect to the spindle by an automatic tool change mechanism. A typical example of a patent disclosing these probes is E]
, 1is U.S. Pat. No. 4,339,714, Kirk
ham, No. 4,118,871, and J, filed April 30, 1981, assigned to the assignee of this invention.
U. Engel, U.S. Patent Application No. 259,257, ``Apparatus for detecting the position of a probe with respect to a workpiece.''

The Kirkham approach described above is disadvantageous because its radio frequency signals are susceptible to electromagnetic interference and must be used within a relatively short probe-to-receiver distance. A problem with the probe system of the Ellis patent is that the ineffective coupling between them requires extreme care to align the probe with a specially constructed sensing device in the spindle head for proper operation. be. The approach to transmitting infrared light disclosed in the Juengel patent cited above is far more advantageous.

However, this also often requires the probe to have its own power source.

It has also been suggested to use contact probes in turning centers, such as lathes, as well as in machining centers. Turning centers differ from machining or milling centers in that the workpiece is turned instead of the tool.

At most turning centers, the beam tool holder is
The tool is mounted at a circumferentially spaced location on a turret that is operable to selectively advance one of the tools relative to the workpiece for machining the workpiece. Generally, tools for performing dimensional machining operations on the workpiece are housed in slots in the turret, while bore tools, such as boring bars, are held in adapters attached to the turret.

Contact probes used in turning centers have a number of problems to overcome that are somewhat different from probes used in machining centers, although the method of transmitting probe signals back to the control equipment still maintains general interest. has. Problem 1 specific to applications in turning centers
One is that the probe remains fixed relative to the turret even when not in use, unlike the situation in the processing center where the probe is inserted into the spindle only when it needs to be used.

As a result, the probe insertion operation cannot be relied upon to energize internal electronic circuits.

One conventional contact probe technique in turning centers is to use an inductive transmission module to send a probe signal through the turret to a controller. See, for example, Renishaw Electrica's LP 2 probe system literature. Unfortunately, this technique requires substantial modification of the turret in order to use the system. As a result, this approach does not allow for easy use on existing machines without the expense and need to take the machine out of service to perform refurbishment work.

Also, although not directly related to the present invention, F'ougere U.S. Pat. No. 3.670,
There are prior art techniques for wireless transmission of dimensional measurement data, such as those disclosed in U.S. Pat.

The present invention is directed to an apparatus and method for performing workpiece inspection operations in a manner that extends the life of the power supplies used in these types of probes. According to one embodiment of the invention, the probe is provided with a detection device that is operative to connect a power source to the probe signal delivery circuit when the detection device receives a certain signal. The probe 7" is a device that generates this "input" signal and sends it wirelessly to the detection device in the probe.
It is located far away from. This signal is generated prior to the anticipated use of the probe to inspect a workpiece and can be initiated by a controller in an automated machine tool.

This power supply is then cut off. In this way, power flows from the power source only when needed. Such an approach is particularly advantageous when the probe is used in a turning center, where it remains fixed relative to the turret even if it is not constantly used for inspection operations. However, the broad concepts of the invention have applicability in a wide range of other machine tool equipment applications.

In a preferred embodiment, the machine tool control device includes:
A flash of infrared light is emitted from a head mounted at a convenient location on the machine tool. As a result, the probe transmission circuit is energized and produces an infrared signal at a certain frequency to indicate that the probe is properly operating and ready for use. The control device then proceeds to an inspection step. When the protrusion of the probe comes into contact with the workpiece, the frequency of the infrared radiation changes. This frequency change is detected remotely and used by the control system to obtain useful information about the workpiece. Preferably, the probe circuit includes a timer that cuts off power to the components of the circuit after a predetermined period of time has elapsed from the initial application cycle or protrusion contact.

Preferably, the head serves the dual purpose of producing a flash firing signal and receiving infrared radiation from the probe. The head includes a built-in flash device and a light detection device. Preferably, the outer surface of the head housing has a lens with an infrared filter. The infrared filter acts to remove visible light from the open beam during the probe introduction procedure. The lens acts to focus infrared rays from the probe onto a photodetector in the head.

In another embodiment, power is supplied to the probe circuit only when the protrusion contacts the reference surface.

In use, the device moves the probe such that the projection contacts the reference surface and initiates a power-up cycle. The probe is then used to inspect the workpiece and is operative to transmit relevant signals back to the remote receiver head.

These and various other advantages of the present invention will become apparent to those skilled in the art upon reviewing the following description and drawings.

(1. Overview) FIG. 1 shows a convex lathe apparatus in simplified form employing various inventive features described below. A numerically controlled turning center 10 is shown with a control 12 for automatically controlling turning operations on a workpiece 14 according to instructions programmed therein. Turning center 10 generally has a rotary chuck 16 having receptacle jaws 18 thereon for holding a workpiece 14 . A plurality of tools 2 to 24 are attached to the turret 20 for performing operations on the inner diameter (ID) portion of the workpiece 14. As shown in FIG. Typically, this type of internal diameter tool has a long handle portion that is held in place on the turret 200 by adapters 26-28. In accordance with the present invention, workpiece insertion probe 30 is mounted to turret 20 in the same manner as tools 22-24. In this embodiment, the probe 30 is connected to the adapter 26
It is attached to the turret 20 by the same adapter 32 as 28.

As is well known in the art, the controller 12, among other things, rotates the turret 20 to place the required tool in the appropriate working position and then rotates the turret until the tool contacts the workpiece to perform the required machining operation. It acts to move 20. Meanwhile, the probe 30 is used for inspecting the workpiece 14. In this embodiment, probe 30 is well known in the art as a contact probe that produces an output signal when a protrusion of the probe contacts the surface of a workpiece or other object. Appropriate separators, digitizers, etc. are used to provide signals to controller 12 indicative of the position of probe 30. As a result, when the signal from the probe 30 indicates contact with the workpiece, the controller 12 can obtain useful information regarding the size of the workpiece, its proper positioning within the chuck, etc.

(A. Flash-on Method) The probe 30 has its own battery power source to provide energy to its signal transmission circuitry. Unfortunately, batteries have a limited useful life. For this reason,
There is a real need for some means of preserving battery life as long as possible. This is particularly true for small probes used in turning centers.

Small probes are also limited by the battery size they can be used with, making energy conservation very important.

One feature of the invention provides two optical communications between probe 30 and flash/receive head 40. The head 40 is 1. Control unit 12 via interface 42
connected to. When controller 12 determines that it is time to use probe 30 for a sensing operation, it generates a signal on line 44 to interface 42, which in turn generates a control signal on line 46 to cause probe 30 to be used for sensing operations.
An optical signal of 40 k is transmitted to the probe 30. In a preferred embodiment, this light signal is a strong flash of infrared light. This flash is triggered by a suitable detection device 48 (see FIG. 2) in the probe 30.
detected by. This flash is caused by the detection device 48
The battery power is then connected to the probe transmission circuit. The probe 30 is a light emitting diode (LED).
Infrared rays of a certain frequency are transmitted to the head 40 through 50 to 54.
Respond to the flash by transmitting to.

This infrared radiation is received by flash/receive head 40, which in turn provides a signal to controller 12 via interface 42 that probe 30 is operating properly and is ready to perform its test operation.

Next, the control unit 12 advances the probe 30 until the protrusion 56 comes into contact with the workpiece 14. The probe 30 is LE
It responds to contact with the protrusion by producing a change in the frequency of the infrared radiation transmitted by D50-54. This frequency change is detected by the interface 42 and sent to the control unit 12. The workpiece inspection operation continues as necessary, with probe 30 transmitting infrared radiation of varying frequency to flash/receive head 40 each time a protrusion is contacted.

Probe 30 includes a timing device that disconnects battery power from the transmission circuit after a predetermined period of time.

This period begins when battery power is first applied to the circuit and is reset each time the protrusion contacts the workpiece. Thus, after the sensing operation is completed, this period of time has elapsed and battery power is disconnected from the transmission circuit.

Therefore, battery power is used only during the expected period of probe use. Battery power is shut off whenever the probe is not in use, thus conserving energy and extending battery replacement intervals.

(B. Contact Insertion Method) FIG. 3 shows another method for extending battery life. In this embodiment, battery power is first connected to the sive lobe transmission circuit by contacting the protrusion 56ff of the probe against a known reference surface 60. The reference plane 60 can be any fixed point inside the machine 1o whose position is known to the control 12. Contact of the probe with surface 60 connects the battery to the probe transmission circuit and initiates transmission from L E D 50 - 54 to flash/receive head 40 . The flash/receive head 40' is similar to the flash/receive head 40 previously described, except that it does not require an internal flash device or a photodetector device 48 within the probe 30'.

Other than this, the two embodiments operate in substantially the same way. After initial operation, the probe is moved to a position for inspecting the workpiece 14, and the probe 30' sends a frequency-varying signal to the flash/receive head "40" whenever a projection contact is made. After a predetermined period of time from the last protrusion contact, the battery is disconnected from the probe transmission circuit.

(■, Probe Structure) FIGS. 4 to 6 show the structure of the probe 30 in detail. The probe housing is characterized by a generally conical intermediate portion 70 and a rearwardly projecting shank or cylindrical portion 72 of small cross-sectional diameter. In this embodiment, the cylindrical portion 72 is hollow with dimensions of approximately 108 mm (4% inches) in length and an outer diameter of approximately 36 mrn (1.4 inches).

The outer dimensions of the cylindrical portion 72 are selected to approximately correspond to the dimensions of the barrel or handle of the tools 22-24.

As a result, the probe 30 can be used in place of one of the tools inside the turret 20 and is held in the adapter 32 as well. As shown most clearly in FIG. 4, this means that the rear wall 76 of the housing portion 70
This can be done by sliding the cylindrical portion 72 into the pocket 74 of the adapter until it abuts the front surface 78 of the adapter. This procedure thereby ensures that the tip of projection 56 is spaced at a known position relative to turret 20.

As a result, during the Zorob inspection operation the control unit 12
It can be placed accurately at position 6. Other means known in the art may also be used to properly space the tips 56 of the thermal protrusions.
using fixation screws (not shown) or other means within the rear of the.

The cylindrical portion 72 desirably serves the dual purpose of providing a battery area and an easily handled support member. The long cylindrical shape of portion 72 allows the use of a long-life "cylindrical" battery, similar in shape to a typical flashlight, to power the probe delivery circuit. Two “C” type lithium batteries 80.82ff
It is desirable to use i. Cylindrical batteries can be used instead of relatively small batteries such as button or disc batteries, providing the probe with a very long useful life at low cost.

Batches 'J80, 82 are slid inside portion 72. A spring loaded cap 84 is then threaded onto the end of section 72 and spring 86 forces regular female terminal 88 against plate 90. The lower surface of the plate 90 is a round conductive layer 9
It has 2. Plate 90 is secured within recess 94 in the inner surface of wall 76 by screws 96 . insulated lead wire 98
is electrically connected to the conductive layer 92 through plated through holes in the plate 90. The opposite end of lead wire 98 is connected to a circuit board 100 containing probe circuitry. An electrical overview of this circuit will be given in the text below. Circuit board 100 is generally circular in shape and has electrical components mounted on both sides thereof. Circuit board 100 is mounted inside intermediate section 70 by suitable fasteners 102 passing through standoff legs 104.

Board 100 also has a centrally located opening 106'f therein through which various leads can pass to facilitate connection to appropriate portions of circuit board 100.

A photodetector device 48 and its associated subassemblies are mounted to the outer ramped surface 110 of the intermediate housing portion 70.

In this example, the photodetector 48 is a Telefunke
PI such as part number DP104f7) available from company n.
It is an N-type diode. The detection device 48 fits within the kneading hole and is held in place by a sloped surface 112 having a window. A transparent plastic layer 114, an infrared filter layer 116, and an O-ring 118 are inserted between the slope 112 and the detection device 48.

Suitable fasteners 120 clamp all of these components into a subassembly mounted within the kneading hole. Detection device 48
The leads from the circuit board 100 pass through the opening 106 and connect to the circuit board 100.
Connected to the soil at an appropriate location.

LEDs 5Q to 54 are mounted adjacent to detection device 48. The LEDs 50-54 are configured to emit light signals in the infrared band, ie, not normally visible to the human eye. For example, LED50 to 54
may be part number 0P290 available from TRW.

Here, the LEDs 5Q to 54 and the detection device 48
It should be noted that the configurations of, together with the configuration of the sloped Zorros surface to which they are attached, combine to optimize several important advantages. For example, LED50
By mounting against the slanted surface 110 of the turret 20, the infrared light emitted thereby is directed forward of the turret 20 at an angle where it can be easily detected at various positions of the flash/receive head 40. The structure of this probe allows the user to
50 - 54 and detection device 48 to allow the probe to be rotated into a position where it is oriented generally in the direction of flash/receive head 40 . As such, it is not necessary to mount the flash/receive head 40 in an absolute spatial position relative to the probe 30, providing greater flexibility of the system in use in different machine tool installations. This provides highly reliable optical communication between probe 30 and flash/receive head 40 while minimizing the number of light emitting elements within probe 30. By minimizing the light emitting elements, the energy drain from the battery is kept as small as possible, thereby further extending battery life.

Around the entire circumference of the intermediate section 700 assembly, wall 76 is attached to the rear portion of section 70 by suitable fasteners 122. An O-ring, such as ring 124, is preferably used to seal the interior of probe 30 from any adverse conditions that the probe may encounter during use in machine tool equipment.

The annular nose piece 130 is connected to the intermediate housing portion 70.
It has a male threaded portion 132 that is threadedly engaged with a threaded portion formed in an inner hole 134 on the front surface. O-ring 13 for sealing purposes
6 is used again. The nosepiece 130 can be of various lengths to increase or decrease the spacing between the tips 56 of the projections as desired. Due to the threaded engagement with the intermediate housing part 70, a variety of such nosepieces can be made and interchanged for different applications.

A switch device 140 is removably attached to the nosepiece 130. The switch device 140 has a circular barbed end structure 142 that includes a peripheral O-ring 146 that is an interference fit against the interior passageway 145 of the nosepiece 130 . One or more locking screws 148 extending perpendicularly to the nosepiece 130 tighten the switch device 140 in place. Switch device 140
can be a variety of structures that act to open or break one or more electrical contacts when protrusion 56 is moved from its resting position. If you are a person skilled in the art,
You will learn about the various structures that serve these general purposes. For one suitable switch structure, see R, F, C; usack, assigned to the assignee of this invention.
No. 388, filed June 14, 1982,
187 in detail. This patent application is mentioned in the text for reference only. In summary,
This structure uses a rocker plate with three equally spaced ball contacts. This swing board has 3 balls.
It is biased by a spring so that it is always pressed against its corresponding current-carrying insert. This inserter pair having three balls acts as a switch (hereinafter referred to as switches 81 to S3 in the main text) and is connected to each other in series. The rocker plates are connected by projections 56.

Whenever the protrusion 56 moves, the rocker plate tilts to lift the ball contact from its corresponding inserter, thereby breaking the electrical connection therebetween.

The three switches in device 140 are connected to circuits on board 100 by wires 150. The other end of the wire 150 has a miniature coaxial connector 152 or other suitable connector that mates with the connector on the end of the replaceable switch device 140. Those skilled in the art will appreciate that these types of switching devices can be very sensitive and may require replacement.

The structure of the present invention allows such exchanges to be made quickly and easily.

Protrusions of various shapes and sizes can be used in conjunction with probe 30. For example, instead of the straight protrusion 560 shown in the figures, a protrusion whose distal end is deflected from the main longitudinal axis of the probe 30 may be used. Various protrusions are interchangeable with switch device 140 and may be attached thereto by use of suitable fasteners, such as locking screws.

The details of the mechanical structure of the flash/receiver head 40 are shown most clearly in FIGS. 7 through 9. uses a generally rectangular container 160 with a detected opening in its front surface 164.

One or more circuit boards 166 are mounted within enclosure 160. Circuit board 166 has various electrical components thereon to perform functions described in detail below. The two most important components are shown in these figures. These elements are a xenon flash tube 168 and a light detection device 170. As previously mentioned, the purpose of flash tube 168 is to produce a short, intense pulse of light to initiate probe operation. Xenon is desirable because it produces light that is rich in infrared radiation. In a preferred embodiment,
Flash tube 168 is part number BUB 0641 available from Siemens. This can produce a flash or light pulse lasting 50 microseconds at an intensity of 100 watts/second. Thermal, other types of suitable light sources can also be used.

Although not absolutely necessary, it is desirable that the visible light produced by flash tube 168 be eliminated to avoid confusion for operators and other personnel in the work area where machine tool 1o is being used. For this purpose, an infrared filter 172 covering the aperture 162 is used.

The infrared filter 172 blocks visible light but allows the infrared light generated by the flash tube 168 to pass therethrough.

Meanwhile, the purpose of the photodetector 1700 is to detect infrared rays transmitted by the probe 30. In this embodiment, photodetection device 170 is a PIN type diode and operates similarly to detection device 48 in probe 30. A convex lens 174 is preferably used at the aperture 162 to focus infrared radiation from the probe 30 onto a photodetector 170 located at the focal point of this lens 174. Tightening the structure of the flash/receiving head 40<
<Secondly, a transparent face plate 176 is provided. The face plate 176 completely covers the opening 162, and there is a gasket (gasket) 171 in between.
It is appropriately attached to the front part 164 by being clamped.

B. Flash/Receive Head Circuit FIG. 10 shows the circuitry used in the flash/receive head 40 of the preferred embodiment.

As previously mentioned, the head 40 is connected to an interface 42 on one or more electrical wires, indicated generally by the 11 reference numeral 46.

A 26 volt alternating current (AC) signal is applied to the primary side of step-up transformer T1. Energy from transformer T1 is further stored in capacitors C8 and C9 connected across the positive and negative electrodes of xenon flash tube 168. In this embodiment, capacitors C8 and C9 store approximately 250-300 volts DC when fully charged.

To flash tube 168, controller 12 generates an appropriate signal level on the line labeled "Control" via interface 42 to cause LED 171 to conduct and emit light. LED171 is a silicon controlled rectifier (
SCR) 173'f: Part of the light-shielding package that includes the light-shielding package. 5CR173 is the primary side of transformer T2 and capacitor 0
10 to form a series circuit. Capacitor CIO, like capacitors C8 and C9, is charged due to the action of transformer T1. When LED171 becomes energized, 5CR173 becomes conductive,
The charge of capacitor CIO is discharged to the primary side of transformer T2. This charge is stepped up to approximately 4,000 volts by transformer T2, the secondary of which is connected to trigger electrode 175 of flash tube 168. This trigger electrode 175 is capacitively coupled to tube 168, and its high voltage is sufficient to ignore gas within the tube. The ionized gas becomes sufficiently conductive to allow the energy from capacitors C8 and 09 to discharge between the positive and negative electrodes producing a short period of very strong flashing sound.

After tube 168 is flashed, the capacitor begins charging again until another flash is applied from interface 42 that initiates the control signal.

Probe 30 responds to the flash by transmitting an infrared signal that is picked up by light detection device 170 in flash/receive head 40 .

Photodetector 170 is connected to a tuned tank circuit consisting of variable inductor L1 and capacitor C2.

In a particular case, the probe 30 will produce infrared radiation that pulses at a frequency of approximately 15 QKHz until the probe contacts contact the object, at which time the frequency changes to approximately 135KHz. The tank circuit in the flash/receive head 40 is tuned to approximately the average of these two frequencies, so that the head circuit can detect either of these probe frequencies, but not at some preselected frequency. This will remove irrelevant frequencies that are out of the band.

The remaining circuitry in FIG. 10 is used to amplify the detected signal transmitted from probe 30, which is connected to interface 42 on the "output" line.

In summary, the head amplifier circuit uses a field effect transistor Q1 whose high input impedance matches that of the tuned circuit to avoid loading problems. Transistor Q2 cooperates with transistor Q1 to amplify the received signal and connects it to an emitter follower circuit used by transistor Q3'. The amplified signal is connected to interface C on the output line via a DC filter capacitor C6 and resistor R7 connected to the emitter of transistor Q3.

Interface 42 contains circuitry that operates to detect these selected probe signal frequencies and produces an output to controller 12 in response. A first signal is generated indicating that the probe is operating properly and a second signal is generated when the protrusion of the probe contacts an object. Suitable circuits for detecting shifts in frequency are described in U.S. Pat. ” is disclosed. The text of this patent application is included for reference only. In summary, such a circuit uses a phase-locked loop circuit to perform frequency shifting keying on the received signal, with either of the touched frequencies energizing a relay upon detection of the other. However, various other methods of detecting probe signals will be within the skill of one of ordinary skill in the art.

C. Probe circuit FIG. 11 is a wiring diagram of the circuit within the probe 30.

PNP transistor QIO transfers power to battery 80.8
The LEDs 50-54 act as switches to selectively turn on and off power to the components used. Transistor QIO is normally non-conducting, so batteries 80, 82 effectively monitor the open circuit to prevent energy from being drained from the battery. However, while the flash continues, the flash/
When receiver head 40 produces its infrared flash, detection device 48 causes current to flow from the battery to inductor L1.

The very fast rise time associated with the light pulses from the xenon flash tube produces a unique light that is easily distinguishable from other light sources in the machine tool field. An infrared filter in the flash/receive head 40 eliminates most of the visible light so that the flash is not visible and can cause irritation to nearby personnel. Light with fast rise time
When the ξ pulse reaches the detection device 48, this pulse is converted into an electrical signal across the inductor coil LIO.

This coil LIO acts as a high pass filter, rejecting steady state or low frequency light pulses that would cause fluorescence in the region.

The current surge flowing through the flash amount detection device 48 is caused by "ringing" in the inductor LIO, as is well known in the art.
cause a phenomenon. This ringing phenomenon is basically about 5
A damped oscillation lasting approximately 500 μsec in response to a 0 μsec flash pulse. Oscillations from inductor L1 are amplified and inverted by inverting amplifier 200. amplifier 200
The output of is connected to the base of transistor QIO. The instantaneous ringing in inductor L1 caused by the flash of light creates a forward bias on both sides of the base/emitter junction of transistor Q10, causing it to conduct. Depending on the conduction state of transistor QIO, power is transferred to batch IJ
80 and 82 are connected to the input side of the circuit elements indicated by 10 and 2 in the drawing. When power is applied to oscillator 202, this oscillator sends pulses to timeout counter 2.
Supply will start for 04. Counter 204 is reset to begin its timeout period when a flash is received from flatten/receive head 40. this is,
The output of amplifier 202 is connected to capacitor C20 and resistor R2.
This is done by an inverter 206 which inverts the positive signal to be shaped into one pulse with an RC time constant of zero. This pulse is passed through the OR gate device 208 to the counter 2.
Connected to the reset input side of 04. As will become clear below, the protrusion 56 of the probe is connected to the switch S1
Whenever contact is made with an object that is reflected by one of the openings in S3, the timeout counter 204 is also reset.

Time-out counter 204 is configured to provide a theoretically low signal on its output line 210 as long as it is not counting or time-out.

This logic low signal on line 210 is connected to inverter 21
2, and this inverter is further inverted by a diode
"Connected to the power side of the amplifier 2000A via D20.

As a result, the output of amplifier 200 is latched low, thereby keeping transistor Q10e conductive and powering the circuit components until such time as counter 204 times out. The expiry period in counter 204 is selected to be long enough to allow controller 12 to begin the actual inspection process with the probe in contact with the workpiece. Generally, a length of several minutes is sufficient for such purposes. The expiration period can be adjusted by a button P20 that defines the oscillation frequency for the time delay oscillator 202. The higher frequency oscillation from oscillator 202 is transmitted to counter 2.
04 causes it to count even faster, which causes the time to run out faster, and vice versa.

In theory, generating various time intervals is well within the abilities of those of ordinary skill in the art.

Carrier oscillator 220 and frequency divider 222 cooperate to provide L
Defines the frequency at which E D 50 - 54 transmits its infrared radiation back to flash/receive head 40 . Until now, oscillator 220 uses a crystal 224 with a known resonant frequency as the master clock. Oscillator 220 acts to shape the oscillation state from crystal 224 into a form suitable for providing clock pulses to digital dividers, such as frequency divider 222, which are well known in the art. In this embodiment, the frequency divider 222 is
It acts to divide the 1.8 MHz noise ξ from the carrier wave oscillator 220 by the number 12, thereby making the frequency of its output signal approximately 150 KHz. The output of frequency divider 222 outputs an LED signal at a frequency defined by the output of the frequency divider.
50-54 are connected to drive transistor Q12 or other suitable circuitry for energizing. Thus, in this example, the flash/receive eight l-' 4
0 When initiating a flush sequence, the probe 30 responds by beginning to transmit infrared radiation at a certain frequency. Probe sending status is flash/
Detected by a light detection device 170 in the receiving head 40, this head also provides an indication to the controller 12 that the probe 3o is properly operating and ready to begin the detection sequence. If the probe 30 does not respond in this manner, appropriate reporting means can be used.

When the probe protrusion 56 comes into contact with the object, one of the three switches 81 to S3 of the probe device 1400 opens. An open state of one of the switches 81-S3 produces two sounds. First, this state resets the time-out counter 201 ffi to the beginning of its time-out sequence. Second, this condition causes a shift in the frequency transmitted by LEDs 59-54. This can be done in various ways. However, in the preferred embodiment, an open condition of one of switches 81-S3 causes comparator 228 to go to a high condition. The output of the converter 228 is connected via an OR gate 201- to the reset input of the counter 204, thereby resetting the counter. Furthermore, comparator 228
The output of is connected to the frequency shifting key input of frequency divider 222 on line 229 to divide it into different numbers, in this example 13, of the clock signal from carrier oscillator 220.
The output signal from the divide-by-two divider 222 that divides the pulse is
This shifts approximately 138 KHz Ki in frequency. Therefore, the frequency of the infrared radiation transmitted by the LEDs 5Q-54 is shifted compared to the frequency transmitted when the probe is first deployed. This frequency shift is detected by photodetector 170 and transmitted to control 12, indicating contact of the protrusion with the surface of the object, typically a workpiece. By knowing the position of the protrusion 56 when this signal is received, the control unit 12 can accurately calculate the dimensions of the workpiece or obtain other useful information.

The controller 12 may cause the probe 30 to move into contact with another workpiece surface each time the probe responds to a change in the infrared radiation transmitted therefrom. The expiration period of the timeout counter 204 is selected to be ~ longer than the period that elapses while the protrusions are in contact. When the sensing operation is completed, the control unit 12 can proceed to other machining operations as needed. Since the energy from the battery is automatically shut off once the counter 204 times out, no further signal needs to be generated to shut off the probe. In such a case, its output line 210 will end up in a high state, resulting in reverse biasing of the base/emitter junction of transistor QIO. Therefore, transistor QIO is placed in a non-conductive state. In this way, only the drain in the battery 80,82 becomes the leakage current of the semiconductor and the photocurrent of the photodetector. Generally, this current is very small and can often be less than 300 microamps. As a result, components requiring more current are disconnected from the battery power supply until actually needed for anticipated use of the probe. These elements also reduce C to save drain on the battery during use.
Preferably, it is made using MOS type semiconductor technology.

In a non-limiting example, carrier oscillator 220 is formed by a crystal controlled transistor device 2N2222, while frequency divider 222 is formed by a National Sem1-co
The oscillator 202 is a National Semlcond LM 4526 available from
The time-out counter 204 is formed from one half of an LM2903 integrated circuit available from National Sem 1-conduct, or Inc., and the timeout counter 204 is an LM 4040, also available from National Sem1-conduct, or Inc.

(■, Liquid Contact Dosing Method The contact dosing method previously described in connection with Figure 3 can be used as an alternative to the flash dosing method described in Chapter ■. Both techniques share the same The purpose of this is to extend battery life.The structure and circuitry of the probes for both these approaches are strikingly similar.A schematic diagram of the probe circuit for the contact-loading method is shown in FIG. Similar to the case of FIG. 11, the same reference number is therefore used to match common components.

Comparing the two figures above, the main difference is the absence of the sensing device 48 and the associated induction coil L10t, due to the resistor R50 and capacitor 050.

This circuit also includes probe switches 81-S3.
and a node N1 connected to the power side of the inverting transformer 2000 Å. Transistor TIO remains non-conducting until such time as contact of protrusion 560 with reference surface 60 (FIG. 3) causes one of switches 81-S3 to open. This is because as long as switches 81-S3 are closed, ie, the probe protrusion is not touching anything, these switches maintain the input to amplifier 200 at approximately ground level. However, when the protrusion 56 contacts the reference surface 60, one of the switches 81-S3 opens and the capacitor 0
50 to start charging. The values of resistors R50 and R18 and capacitor C50 are inverted by amplifier 200 before capacitor C50 connects to transistor CIQ.
It is desirable to be contacted in such a way that it provides an RC time constant that delays the time it takes to build up to sufficient voltage to turn it on. For this purpose, the control unit 12
6 is required to be pressed against the reference surface 60 for a certain period of time, for example about 1 second. This procedure will ensure that accidental bumps on the prongs of the probe or other extraneous factors such as electrical noise will not falsely trigger the probe.

Once capacitor 050 has been fully neutralized, transistor QIO is turned on, providing power to the Proso transmission element from battery 80.82. The counter 204 is reset and transistors Q], [a-
Its output signal is provided on line 210 to latch into conduction. In this embodiment, the protrusion 5 of the probe
6 is in contact with the reference surface, the frequency divider will initially produce the lower of the two output frequencies.

However, the controller 12 may be suitably programmed to view this initial probe configuration as an indication that the probe is properly loaded and ready to proceed to inspect the workpiece.

Assuming that the probe 30' is operating properly, the controller J2 will now proceed to the workpiece inspection step, where the protrusion 56 will contact the surface of the workpiece. Once the protrusion 56 moves away from the reference plane 60, the switches $1-S3 are closed and the frequency divider 22
2) and drive LEDs 50 to 54 at other frequencies.

As soon as the projection contacts the surface of the workpiece, switch 8 is activated.
One of S1 to S3 is opened again and the comparator 228 is tripped. This results in a reset state of timeout counter 204. The tripping action of comparator 228 also sends its output on line 229 to frequency divider 222K, which in turn transmits its output to L E D 50-54.
produces a shift in the frequency of the output. This procedure continues until such time as the workpiece inspection process is complete and once the timer 204 expires, battery power is automatically disconnected from the probe's circuitry.

SUMMARY After reading the above description, it will be apparent to those skilled in the art that this text discloses several important improvements in the art of inspecting workpieces. Each embodiment has been described in connection with the best presently contemplated method for carrying out the inventive idea. However, no attempt has been made to list all alternatives or modifications to the general concept of the invention.

Such modifications and improvements will become apparent to those skilled in the art upon consideration of the drawings, text, and appended claims. For example, it will be appreciated that flash or contact methods of injection may be performed using different types of probes than those shown herein.

Therefore, while the invention has been described with respect to specific instances thereof, its true scope should be gauged in light of the following claims and their equivalents.

[Brief explanation of the drawing]

FIG. 1 is a usage environment diagram showing a detection system provided according to the teachings of the present invention for use in an automatic lathe; FIG. 2 is a perspective view showing a detection system using a flush injection method according to an embodiment of the present invention; FIG. 3 is a perspective view illustrating the use of a detection system using a contact injection technique according to another embodiment; FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 4; FIG. 6 is an exploded perspective view of the probe shown in FIG. 4; and FIG. 7 is a cross-sectional view of the probe shown in FIG. , Perspective view of Rad, No. 8
9 is a plan view showing a circuit board used in the flash/receive head of FIG. 7; FIG. 10 is a cross-sectional view taken along line 8-8 in FIG. FIG. 11 is a schematic diagram of a circuit used in a probe of one embodiment of the invention using the flash injection method, and FIG. 12 is a schematic diagram of a circuit used in a probe using a contact injection method. FIG. 2 is a schematic diagram of a circuit.

Claims (1)

[Scope of Claims] (1) A device used in a machine tool apparatus, including a first device for detecting information about the workpiece, the first device detecting information about the workpiece to a remote receiving device. The first device includes a circuit device for transmitting information, a power source, and a detection device that is activated to connect the circuit from the power source to the circuit and is activated upon receipt of a signal. a second device located at a distance from the power source for initiating power supply to the circuit by wirelessly transmitting the certain signal to the detection device, thereby draining power from the power source; is minimized by selectively using energy therefrom only during the expected period of use. (2) The device according to claim 1, wherein the circuit device includes a timer device for cutting off power supply to the circuit from the power source after a predetermined period. (3) The predetermined period of time is measured from the time when power from the power supply is first sent to the circuit, or from an indication that the first device performs a detection operation. The device according to claim 2. (4) In a device used in a machine tool device that detects the state of contact with a workpiece, a protrusion for contacting the workpiece and information related to the contact state of the protrusion to a remote receiving device. a circuit arrangement for wirelessly transmitting an optical signal, a battery power source, and a photodetection device operative to connect power from the battery to the circuit and to enable its operation upon receipt of a given optical signal. a probe device located at a location remote from the Zurog that draws power from the battery by transmitting the certain optical signal to a photodetection device in the probe prior to anticipated use thereof; 1. A first device for minimizing the loss of energy to a minimum. (5) The circuitry of the probe includes a timer that cuts off the supply of power from the battery after a predetermined period of time has elapsed from generation of the certain signal or contact of the protrusion with the workpiece. An apparatus according to claim 4, characterized in that: 6. The apparatus of claim 5, wherein said certain optical signal is a very intense infrared flash. Claim 4, wherein the probe further comprises: a light transmission device connected to the circuit arrangement and operative to emit an infrared signal indicative of contact of the protrusion with the workpiece. (8) The first device further includes a housing having a flash tube, a light detection device, and an infrared filter cover for an opening in a wall of the housing. 4. The device of claim 4. (9) The device of claim 8, wherein the housing further includes a lens that focuses infrared radiation from the probe onto the photodetector. ) the probe circuit generates a frequency that energizes the optical transmission device when power from the battery is first applied and produces a shift in frequency when the protrusion contacts a workpiece; 8. A device according to claim 7, characterized in that it operates as follows. (11) A method of using a battery-powered probe in machine tool equipment, comprising: generating an optical signal prior to anticipated use of the probe; detecting the signal at the probe; and detecting the signal at the probe; connecting power from the battery to electrical components within the probe for a period sufficient to allow the probe to perform the desired operation on the workpiece using the signal obtained by how to. 02) transmitting an optical signal of a certain frequency from the probe when power from the battery is first supplied to a component of the circuit; and transmitting an optical signal of a certain frequency from the probe when the probe contacts the workpiece; 12. The method of claim 11, further comprising the step of shifting the frequency of the optical signal. (13) The method further includes the step of cutting off the supply of power from the battery to the circuit element after a predetermined period of time has elapsed since the detection of the optical signal or the contact of the probe with the workpiece. A method according to claim 11. ■ A probe that detects information about a workpiece includes a circuit device that wirelessly transmits information about the detected workpiece to a receiving device at a remote location, a battery power source, and power from the battery to the circuit device. 1. A probe characterized in that it is provided with a detection device which enables its operation upon receipt of a certain signal transmitted by radio. (15) The probe according to claim 13, wherein the detection device is a photodetection device that operates in response to an optical signal. (16) The probe of claim 14, wherein said certain optical signal is a very intense infrared flash. 07) A device used in a detection device used in a machine tool, comprising a container containing a light source and a light detection device, a device for energizing the light source prior to a detection operation, and a device for the light detection device. and a device for detecting the reception of an optical signal 9 which is connected to the terminal and contains information regarding the detection operation. (18) the light source is a flash tube, the light detection device is responsive to infrared light, and the container includes an infrared filter for substantially removing visible light generated from the flash tube. 17. The device according to claim 16, characterized in that: -α wing The container further includes a lens device for focusing the optical signal onto the photodetecting device.
Apparatus described in section. (20) A method of using a battery-powered probe in a machine tool device, comprising: (7) bringing the probe into contact with a reference surface; and in response, applying power from the battery to electrical components within the probe; 1. Connecting power to the battery using the probe, detecting information about the workpiece using the probe, and disconnecting power from the battery after a predetermined period of time. 21. The method of claim 20, further comprising the step of: (2I) wirelessly transmitting information regarding the detected workpiece to a receiving device at a remote location. (24) a probe for detecting information about a workpiece, comprising at least one optical transmission device for transmitting the information to a receiving device at a remote location, and an electrical component for energizing the optical device; and at least one battery for supplying energy to the component, the probe including a light detection device and an inductor connected to the battery and responsive to a flash of light generated at a remote location. an input circuit device operative to produce an output signal with an amplitude of (23) generating a latch signal to hold the switching device in a certain state, thereby maintaining the connection of the battery for a predetermined period of time; a timer device; a first device for detecting when the probe contacts an object; and a second device for generating at least two different frequencies to energize the light transfer device; A device is connected to the timer device and the second device and is operative to reset the timer and produce a shift in frequency when the probe comes into contact with an object. A probe according to scope 22. (24) A probe for detecting information about a workpiece, the probe comprising at least one optical transmission device for transmitting information to a remote receiving device and energizing the optical device. A probe that includes a reservoir electrical component and at least one battery that supplies energy to the component, wherein energy from the battery is selectively applied to the component depending on its condition. a switch device connected to the component; and in response to contact of the probe with an object, generates a signal sufficient to change the state of the switch device, thereby directing energy from the battery to the component. (25) The probe includes at least one normally open contact that is closed when it comes into contact with an object, and the input circuit connects the battery and the contact. connected to the battery to store energy from the battery when the contact is opened;
25. The probe of claim 24 including a capacitive coupling device operative to produce an output signal of sufficient amplitude after a predetermined period of time to change the state of the switch device. (26) a timer device that generates a latch signal to hold the switch device in a certain state to maintain battery connection with the component for a predetermined period of time, and detects when the probe comes into contact with an object; a first device; and a second device for generating at least two different frequencies to energize the light transmission device, the first device being connected to the timer device and the second device. 26. The probe of claim 25, operative to reset the timer to produce a shift in frequency when the probe contacts an object.