Abstract:
The present invention provides an adapter table apparatus having sensor function for fixing a work-piece that is used for positioning or centering of compact machine tool, which is attached to an X-Y table, comprises an adapter table including a main body for fixing a work-piece and a member worn to and electrically insulated from the main body directly mountable to the X-Y table, a magnet electrode which electrically contacts a collet chuck at a distal end portion of vertical main spindle of machine tool or an electrode holding member which is fixed to a distal end sleeve of the vertical main spindle and an operating panel that accommodates a circuit for detecting electric contact of first and second contact s, first of which is a conductive surface of the work-piece or a surface of the main body of the adapter table and second of which is a distal end portion of tool or probe for contact detection that is held by the collet chuck by providing a pair of input lines that is in an electrically connected state separately from these first and second contacts.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an adapter table apparatus having sensor function for fixing a work-piece that is used for positioning or centering for compact machine tool with a vertical main spindle.  
           [0003]    2. Description of the Prior Art  
           [0004]    A centering bar in which a measuring terminal eccentrically rotates until contacting a work-piece has been generally provided as a device for precisely performing positioning or centering in a machine tool. An operator visually confirms a moment when convergence of eccentric rotation and slice occur. Such position is determined as a reference. Even a skilled operator cannot easily and instantaneously catch a convergence state of such measuring terminal.  
           [0005]    A touch sensor for automatic fine detection and an light emission alarm type centering bar have been provided as attempts to automate confirmation of the state of the centering bar. In accordance with the touch sensor, the moment when eccentrically rotating centering bar contacts a work-piece is electrically detected. Thus, a structure is highly complicated and extremely expensive device is provided.  
           [0006]    In accordance with the light emission alarm type centering bar, when the centering bar contacts the work-piece, a conducting circuit from a main spindle via a machine main body to a stock vice is closed. Then, an LED is emitted and a buzzer rang. Attention must be paid to detect the moment of contact by such signal. In the electrically conducting circuit of the machine, a contact resistance such as a ball bearing of the main spindle or a stock vice supporting mechanism may be varied depending on a type of machine or a usage state. Further, as a contact detection circuit, a battery, light emission means and sound means are incorporated into the centering bar, the centering bar becomes a large size and cannot be applied to a compact machine.  
           [0007]    Centering of work-piece or positioning of origin especially when one product is manufactured by a compact milling machine or a drilling machine is performed as follows. Namely, the work-piece is marked at any portion thereof and then centering or positioning is performed by using a gauge, a dial gauge, a digital scale or a score by the naked eye. Alternatively, a tool is rotated and the tool contacts a side surface of work-piece. A reference position is determined by a change of sound at this moment. In order to compensate for inaccuracy, trial cutting or milling is performed. Thus, additional labor and cost are required.  
         SUMMARY OF THE INVENTION  
         [0008]    An object of the present invention is to provide a stock vice related device usable in a compact machine tool that a measuring probe instead of a centering bar, a reliable electrical conducting function between the probe or tool and a work fixing tool instead of machine main body and a light emission alarm function are provided or electrically connected.  
           [0009]    In order to accomplish the aforementioned object, the present invention provides an adapter table apparatus having sensor function for fixing a work-piece which is attached to an X-Y table of machine tool, comprising: an adapter table including a main body for fixing the work-piece and a member worn to and electrically insulated from the main body, directly mountable to the X-Y table; a magnet electrode that is used for magnetically attracting electrode means to a collet chuck at a distal end portion of vertical main spindle of the machine tool, or an electrode holding member fixed to a distal end sleeve of the vertical main spindle so as to be electrically contactable; and an operating panel that accommodates a circuit for detecting electric contact of first and second contact means, first of which is a conductive surface of the work-piece or a surface of main body of the adapter table which fixes the work-piece and second of which is a distal end portion of tool or contact detection probe means gripped by the collet chuck by providing paired detection input sections which are connected to the main body of the adapter table which electrically contacts the first contact and the magnet electrode which electrically contacts the second contact means.  
           [0010]    In accordance with the present invention, instead of the magnet electrode in the adapter table having sensor function, a clip electrode which grips a tool or a contact detection probe means gripped by a collet chuck at a distal end portion of vertical main spindle of the machine tool and electrode holding means fixed to a distal end sleeve of the vertical main spindle so as to be electrically contactable may be used. Accordingly, paired input lines of the contact detection circuit are connected to the main body of the adapter table which electrically contacts the first contact means and the clip electrode which electrically contacts the second contact means.  
           [0011]    In accordance with the present invention, the clip electrode comprises a pliers-like metallic unit formed of a stable piece and a movable piece, distal end portions of the stable piece and the movable piece are always urged by a spring loaded at a crossing portion of the stable piece and the movable piece such that paired grip end portions which press-contact with each other are formed, conductive metallic bristles are applied to opposing surfaces each of which is formed between a distal end of grip end portion and the crossing portion so as to mesh with each other, so that a shank portion of the tool or the contact detection probe means or electrode means fixed to and connected to the distal end sleeve of the vertical main spindle is gripped so as to be slidable and electrically contactable.  
           [0012]    In accordance with the present invention, in the probe means, a probe gauge is protruded from a distal end of shank-shaped sleeve, a rear end of the probe gauge within the shank-shaped sleeve abuts against a buffer slider so as to be supported by the same, the buffer slider is spring-supported from a rear end of the shank-shaped sleeve so as to press the probe gauge, a collar portion of the probe gauge is anchored to a distal end opening portion within the shank-shaped sleeve, so that a play including returning retracting and deflection of distal end of the probe gauge is provided.  
           [0013]    In accordance with the present invention, the table according to any the above constitutions, wherein in the probe means, a distal end portion of ball receiving shaft is protruded from a distal end portion of sleeve-shaped probe main body that is extended from a reduced diameter portion of cone formed at the sleeve-shaped main body, a rear end of ball receiving shaft is formed as a slim core shaft, the core shaft is guided to a central hole of guide portion which is fixed to a wide opening side of the cone formed at the probe main body, the ball receiving shaft is pressed by a coil spring which is inserted between the guide portion and an end of the core shaft of the ball receiving shaft, so that the ball receiving shaft is maintained at a position that a distal end of core shaft is anchored to the guide portion, a clamp ring for clamping in a chuck manner a shank of tool inserted into the probe main body is provided at a rear end of probe main body, a probe that is detachable with respect to the tool and in which a ball supported at the distal end is used for a stylus is structured. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view showing an example of machine tool to which the present invention is applied.  
         [0015]    [0015]FIG. 2A is a vertical sectional view of dedicated probe used for an embodiment of the present invention.  
         [0016]    [0016]FIG. 2B is a side view of the dedicated probe used for an embodiment of the present invention.  
         [0017]    [0017]FIG. 3A is a vertical sectional view of detachable probe used for the embodiment of the present invention.  
         [0018]    [0018]FIG. 3B is a side view of the detachable probe used for the embodiment of the present invention.  
         [0019]    [0019]FIG. 4A is a side view of clip for electric contact with a probe according to the embodiment of the present invention.  
         [0020]    [0020]FIG. 4B is a rear view of the clip for electric contact with a probe according to the embodiment of the present invention.  
         [0021]    [0021]FIG. 5A is a schematic side view showing a contact circuit when the probe is mounted to the machine tool to which the present invention is applied.  
         [0022]    [0022]FIG. 5B is a schematic side view showing a contact circuit when the tool is mounted and operated to which the present invention is applied.  
         [0023]    [0023]FIG. 6 is a perspective view showing a basic embodiment of stock vice of the present invention.  
         [0024]    [0024]FIG. 7A is a plan view of the stock vice of FIG. 6.  
         [0025]    [0025]FIG. 7B is a front cross-sectional view of the stock vice, including a partially broken cross-sectional view.  
         [0026]    [0026]FIG. 7C is a cross-sectional view of FIG. 7A taken along a line A-A′.  
         [0027]    [0027]FIG. 8 is a perspective view of T block nut for fixing the adapter table of the present invention to a main machine X-Y table.  
         [0028]    [0028]FIG. 9 is a perspective view showing a state of simply fixing the adapter table of the present invention to the main machine X-Y table using an L-shaped clamp piece.  
         [0029]    [0029]FIG. 10A is a partial plan view of table showing a detailed structure of axial direction positioning frame for the adapter table of the present invention.  
         [0030]    [0030]FIG. 10B is a partial front view of the table described above.  
         [0031]    [0031]FIG. 10C is a partial side view of the table described above.  
         [0032]    [0032]FIG. 10D is a rear view of the table described above.  
         [0033]    [0033]FIG. 11A is a circuit diagram showing an operating panel circuit of the present invention.  
         [0034]    [0034]FIG. 11B is an arrangement view of mounting cable in the circuit of the present invention.  
         [0035]    [0035]FIG. 12A is a plan view of magnetic electrode serving as an electric connection terminal from the probe.  
         [0036]    [0036]FIG. 12B is a side view of the magnetic electrode described above.  
         [0037]    [0037]FIG. 12C is a side sectional view of the magnetic electrode described above.  
         [0038]    [0038]FIG. 13 is a side view of magnetic contact connected to an additional terminal of the operating panel circuit.  
         [0039]    [0039]FIG. 14A shows a waveform of checking terminal of the operating panel circuit.  
         [0040]    [0040]FIG. 14B shows a waveform of lighting directly contacted display LED.  
         [0041]    [0041]FIG. 14C shows a waveform of lighting continuously contacted display LED.  
         [0042]    [0042]FIG. 14D shows a pulse waveform of generated speaker sound.  
         [0043]    [0043]FIG. 15 is a perspective view showing an embodiment that an ordinary stock vice is supported by the adapter table of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0044]    [0044]FIG. 1 shows an exterior of embodiment that a stock vice of the present invention is used for a milling machine. Referring to FIG. 1, a probe  4  serving as a centering or positioning element is held by a collet chuck  3  at an end of main spindle which is protruded downward from a spindle housing  2  of milling machine  1 . In this case, the probe  4  is electrically conductively connected to a magnet electrode  6  which has a display panel and is magnetically attracted to a distal end of metallic arm  5  which is mounted to a main spindle sleeve disposed above the collet chuck  3 . Further, the probe  4  is conducted via an electric cable  6   a  extended from the magnetic electrode  6  to an operating panel  7  which has a function of detecting contact with a work-piece and other functions.  
         [0045]    A specific core wire in the electric cable  6   a  serves as one line of a pair of detection input lines for a contact detection circuit included in the operating panel  7 . An adapter table  10  of the present invention which has a work-piece  8  and a work-piece holder  9  for clamping and fixing the work-piece  8  serves as another input line. The operating panel  7  is fixed to a front side surface of the adapter table  10  by a screw or the like. The screw constitutis a contact detection input terminal for a circuit to be described later. The table  10  is mounted on a main machine X-Y table  11  as described later.  
         [0046]    [0046]FIGS. 2A and 2B show a dedicated probe which serves as gauge for initial setting and sensor among probes serving as input terminals for the contact detection circuit. Referring to FIG. 2A, in a dedicated probe  4   a , a probe gauge  14  is protruded from a distal end of shank-shaped sleeve  13 . A rear end of the probe gauge within the sleeve  13  abuts against a buffer slider  15  and is supported by the same. The buffer slider  15  presses the probe gauge  14  by being supported by a spring  16  from backward (upward in the figure), so that the probe gauge  14  is maintained at a position that a collar portion  14   a  thereof is anchored to a distal end opening of the shank sleeve  13 . A reference numeral  17  indicates a screw for gauge exchange and adjustment which also functions as a spring seat for the spring  16 . A play outliningly shown by broken lines of FIG. 2B is provided for a case that a side surface of the probe gauge  14  abuts an object to be positioned (work-piece or stock vice). An available pin gauge can be effectively utilized for the probe gauge  14 .  
         [0047]    [0047]FIGS. 3A and 3B show a second probe, i.e., a detachable probe  4   b  for centering which is set to operating or mounted end mill or shank of drill. Referring to FIG. 3A, a probe main body  4   b  is formed in a sleeve shape. A distal end of ball receiving shaft  18  serving as a probe shaft is protruded from a distal end portion which is extended from a reduced diameter portion of a cone formed at the main body. A ball  19  at the distal end of the ball receiving shaft is used as a stylus for searching a hole or a punch hole formed at a work-piece. In this way, fine adjustment for centering or positioning is performed.  
         [0048]    A slim core shaft is formed at a rear end of the ball receiving shaft  18 . The core shaft is guided to a central hole of plate-shaped guide portion  20  which is fixed to a broad opening side of the cone formed at the probe main body  4   b . The ball receiving shaft  18  is pressed by a coil spring  21  which is inserted between the plate-shaped guide portion  20  and an end of the core shaft. In this way, the ball receiving shaft  18  is maintained at a position that a head nut  22  placed at the distal end of the core shaft is anchored to the plate-shaped guide portion  20 . The rear end of the probe main body  4   b  is provided with a slit  23  serving as a play at a time of being shrunk in a direction of reducing a diameter when a shank of tool is clamped. A clamp ring  25  which is engaged with a thread  24  formed toward a bottom portion of the slit  23  is placed at an outer periphery of the rear end of the probe main body  4   b.    
         [0049]    [0049]FIGS. 4A and 4B show main portions of clip electrode  12  for nipping the above-described probe  4  instead of the magnet electrode  6  shown in FIG. 1. The clip electrode  12  is formed of a pliers-like metallic unit. A stable piece  12   a  and a movable piece  12   b  are always urged by a spring mounted to their crossing portion  12   c  such that distal end portions (grip end portions) of the stable piece and the movable piece press-contact. Conductive bristles  26  are applied to a portion between the distal end portion of either of the pair of grip end portions and the crossing portion  12   c  so as to mesh with bristles formed at a portion between the distal end portion of another of the grip end portion pair and the crossing portion  12   c . A lead wire  27  which is conductively coupled to the metallic bristles  26  of the stable piece is extended toward the rear end of the stable piece and connected to the cable  6  (FIG. 1).  
         [0050]    [0050]FIG. 5 shows a typical aspect of using the clip electrode  12 . The clip electrode  12  is supported by, e.g., a clip supporting rod  5   a  which is suspended from a distal end of the metallic arm  5  which is protruded from the main spindle sleeve. At this position, the shank portion of the probe  4  can be nipped, as shown in FIG. 5, by the metallic bristles  26  at the grip end portions substantially without contact resistance. Further, a shank of end mill or drill can also be nipped. This aspect can be applied to a case in which such tool is rotating.  
         [0051]    [0051]FIG. 6 shows a perspective view of the adapter table  10  which comprises the operating panel  7  serving as the main portion of the present invention. As a main body portion of the table  10  has functions of stock vice and X-Y table, the main body portion is made of hard steel alloy which is the same as the main machine X-Y table  11 . The table  10  is supported by the X-Y table  11  (FIG. 1) while maintaining electric insulation. For this reason, a high quality insulating plate  28  is adhered to a back surface of the main body portion of the table  10 . The insulating plate  28  is further adhered to a protective plate  29  which is formed of a finished plate with quenched surface and protected by the same. The protective plate  29  is contact-supported by and fixed to the main machine X-Y table  11 .  
         [0052]    A plurality of grooves  30  with inversed T-shaped configuration are formed on the surface of the main body portion of the table  10  along a lengthwise (transverse) direction. Insulating covers  31 ,  31 ′ are attached to a front surface and a rear surface of the main body portion. The operating panel  7  is mounted to the insulating cover  31  at the front surface. The operating panel  7  has, at its upper surface, a contact state display LED  32 , a certain time display LED  33 , an electrode detaching display LED  34  and a power source switch button  35 . An exterior output terminal  36  and a magnet electrode connector jack  37  are provided at a left side surface of the operating panel  7 . A table X axis positioning frame  39  is mounted via an insulating plate  38  to a front end of each of shelf-shaped portions  10   a ,  10   b  disposed at left and right side surfaces of the table  10 .  
         [0053]    Mounting holes  40  for the main machine X-Y table  11  are placed at the front and rear ends of each of the shelf-shaped portions  10   a ,  10   b  at the right and left side surfaces. As shown in FIG. 7, a bolt which is inserted into each of the mounting holes  40  is screwed into a T block nut  42  inserted into an inversed T-shaped groove  41  at the main machine X-Y table  11 . As a result, the adapter table  10  is fixed to the table  11 . A reference numeral  42   a  indicates a lock piece of the T block nut  42 . When the lock piece  42   a  abuts each of the shelf-shaped portions  10   a ,  10   b  at the left and right side surfaces, a screw hole of the nut  42  is aligned with the mounting hole  4 . An outline of the T block nut  42  is shown in FIG. 8. A main body of the nut  42  has an inversed T-shaped cross-section. The lock piece portion  42   a  is fixed to or integrally formed with one end of a top surface. The screw hole  42   b  is formed at another end.  
         [0054]    [0054]FIG. 9 shows a state of temporarily fixing an adapter table  10 ′ which does not have shelf-shaped portions for fine positioning at left and right side surfaces to the main machine X-Y table  11  by an L-shaped clamp piece  43 . The L-shaped clamp piece  43  is formed of an insulator leg  44  which stands upright on the surface of the X-Y table  11 , a clamp piece main body  45  made of quenched steel plate with its one end being fixed to the insulator leg  44  and an insulating plate  46  which coats the surface of the clamp piece main body  45 . A bolt  47  which is inserted via a washer into an elongated hole passing through the main body  45  and the insulating plate  46  is screwed into a T nut (not shown) hidden in the inversed T-shaped groove of the X-Y table  11 . As a result, the adapter table  10 ′ can be fixed.  
         [0055]    The frame  39  for axial direction positioning of the table  10  will be described with reference to FIGS. 6, 9 and  10 . The frame  39  has an adjustment knob  49  which is protruded from a front surface of lateral bent portion  48  at the front end. The reason why fine positional adjustment by the knob  49  is required is as follows. Namely, at a time of mounting the adapter table  10  by screwed into the T block nut  42 , variations in the X axis are generated (the adapter table  10  is not precisely parallel to the main machine X-Y table  11 ) depending on a difference between fastened states of the screws (because the mounting hole  40  has a small room for passing through a screw). The knob  49  is formed as a head for sliding screw  51  which is free revolving bridged and supported between the lateral bent portion  48  and a lateral protrusion  50  at a rear portion of the frame  39 .  
         [0056]    When the knob  49  is rotated and a relative position of slide block  52  which is supported by (screwed into) the slide screw  51  is finely adjusted, the position of the adapter table  10  relative to the main machine X-Y table  11  is finely adjusted by an integrally formed tapered pin  53  inserted into the inversed T-shaped groove  41  formed at the main machine X-Y table  11 . An operator obtains a precise position of the table  10  with respect to left and right side surfaces thereof by the fine adjustment. Then, the operator can strongly fasten the aforementioned screw within the mounting hole  40  which is temporarily fastened until the screw is set. The positioning frame  39  is fixed, by a bolt  54  with insulating bush, via the insulating plate  38  to each of the shelf-shaped portions  10   a ,  10   b  at the left and right side surfaces. The tapered pin  53  is fixed to the slide block  52  by a fixing screw  55  with insulating bush.  
         [0057]    [0057]FIG. 11A shows a structural example of circuit for detecting contact between a probe and a work-piece (adapter table) within the operating panel  7  in which the above-described exterior elements  32  to  36  are disposed. Such elements are indicated by circuit element symbols to which the same reference numerals are attached. Referring to FIG. 11A, the magnet electrode  6  with display panel is magnetically attracted to the collet chuck  3  which holds the probe gauge  4  and conductively connected to the same. Referring to a partial front view of FIG. 11B, the magnet electrode  6  with display panel is, as in FIG. 1, magnetically attracted to the distal end of the metallic arm  5  and conductively connected to the same. Further, the magnet electrode  6  is, as in FIG. 11A, also attracted and fixed to the collet chuck  3  as shown by broken lines. A conductivity between the probe gauge  4  and the magnet electrode  6  in FIG. 11A is not substantially different from that of FIG. 11B. Thus, a difference in a circuit operation is not generated. “An operating panel circuit ( 7 )” refers to as the whole circuit within the operating panel  7 .  
         [0058]    In the operating panel circuit ( 7 ), when the magnet electrode  6  with display panel is magnetically attracted to the collet chuck  3 , a pair of contacts  60   a  and  60   b  with magnetic path within the magnet electrode  6  is short-ciucuited via the surface of the attracted collet chuck  3 . The contact  60   a  is connected via the core wire  61   a  in the electric cable  6   a  to a common line  62  within the operating panel circuit. On the other hand, a plus voltage of power source within the operating panel circuit is connected via a protective circuit  58  with functions of noise filter and over-voltage absorption to a power source side contact of the switch  35  from a built battery  56  or an exterior adapter power source (not shown) connected to an adapter terminal  57 . The circuit side contact of the switch  35  is connected via voltage dividing resistances  63   a ,  63   b , an LED  34   a , the cable core wire  61   c  and an LED  34   b  within the magnet electrode  6  to the shorted contact  60   a  or  60   b  with magnetic path.  
         [0059]    Accordingly, when the power source switch  59  is turned on, a circuit from the switch via the LEDs  34   a ,  34   b  and contacts  60   a ,  60   b  to the common line  62  (minus line for the power source) is connected between ends of direct current power source  56  or  58 . Thus, the LEDs  34   a  and  34   b  are switched on and display an on state of the operating panel circuit ( 7 ). Then, when the probe  4  mounted to the collet chuck  3  contacts the work-piece  8 , the table  10  which supports (electrically contacts) the work-piece  8  and is insulated from the machine tool main body is conducted via the contact  60   a  or  60   b  with magnetic path to the common line  62 . The table  10  serving as a conductor is represented by the connection terminal  65  in the operating panel circuit. Thus, the common line  62  and the connection terminal  65  form an input portion in a contact detection circuit.  
         [0060]    A contact detection circuit  69  is formed of a transistor  66 , a detection resistance  67  and a counter current preventing diode  68  and inserted in series between the power source switch  35  and the connection terminal  65  in the operating panel circuit ( 7 ). In the contact detection circuit  69 , since the transistor  66  has a base connected to nodes of the voltage dividing resistances  63   a  and  63   b , a base current flows. Collector-emitter is perfectly conducted by the contact detection circuit  69  being closed by contact of probe. A node of the detection resistance  67  and the diode  68  that is connected via a collector resistance of the transistor  66  which is open in an ordinary state (in a non-contact state of probe) to the source voltage  8  (e.g., 5V) has the same potential as that of the common line  62  (zero potential) via the diode  68  and the connection terminal  65  by a current flowing through the contact detection circuit  69 . A lighting timer circuit originated from a check terminal  77  is urged.  
         [0061]    The lighting timer circuit is formed of a noise limiter  71  made of CR filter, a schmitt trigger  72  and an one shot timer  73 . When an input of the noise limiter  71  is stabilized at a low level, the schmitt trigger  72  has a predetermined output level. An operating panel side contact state LED  32   a  and a magnet electrode side contact state LED  32   b  are lit via resistances  74  and  75 . Further, the one shot timer  73  which receives a predetermined output of the schmitt trigger  72  generates a delayed output which lasts for 1 to 2 seconds and lights an operating panel side certain time LED  33   a  and a magnet electrode side certain time LED  33   b  via resistances  76  and  77 .  
         [0062]    Functions of aforementioned contact state LEDs  32   a ,  32   b  and certain time LEDs  33   a ,  33   b  will be described. In positioning between a probe and a work-piece, the LEDs  32   a  and  32   b  light only when the probe contacts the work-piece (such display is of course effectively utilized) If the probe contacts the work-piece for only an instant and then the LEDs light for only an instant, such lighting may be missed. Further, if contact of the probe with the work-piece is instable in spite of continuous contact, the LEDs are turned on and off and thus such lightning is hardly seen. Thus, the LEDs  33   a  and  33   b  light for 1 to 2 seconds even in an instantaneous contact such that an operator does not miss lighting.  
         [0063]    An output of the schmitt trigger  72  is connected to a positive input of second one shot timer  78  which forms a sound timer circuit separately from the aforementioned lighting timer circuit. The one shot timer  78  generates a short time output of less than 0.1 to 0.2 second and such output is supplied to an input of sound oscillation circuit  79 . An output of the oscillation circuit  79  is connected to a base of transistor  81  in a sound circuit which is inserted between the power source switch  35  circuit side and the common line  62  and includes a buzzer or a speaker  80 . By the transistor  81  being conducted, instantaneous buzzer or speaker sound is generated.  
         [0064]    It is assumed that the above-described circuit operations are performed when the power source switch  35  is turned on and then a base potential is established at the transistor  66 . Namely, the LED  34   a  of the base circuit must be electrically connected via the collet chuck  3  to the contact  60   a  with magnetic path within the magnetic electrode  6  connected to the common line  62  while passing through the series LED  34   b  and the contact  60   b  with magnetic path. For this reason, as shown in FIGS. 12A through 12C, the contacts  60   a  and  60   b  with magnetic path of the magnet electrode  6  are mounted so as to correspond to a flat distal end portion of the arm  5  shown in FIGS. 1 and 11B and to one outer peripheral surface with narrow side of the polygonal collet chuck  3  shown in FIG. 11A.  
         [0065]    Namely, the contacts  60   a  and  60   b  with magnetic path are always partially exposed from a concave opening edge  6   b  of main body case of the magnet electrode  6 . The contacts  60   a  and  60   b  with magnetic path are attracted to wide metallic flat surfaces by elastic or good conductive metallic plates  82   a  and  82   b  such as phosphor bronze plates while slightly being protruded from the concave opening edge  6   b . Further, the contacts are attracted while being accommodated within the concave opening edge  6   b  and narrow metallic flat surfaces being covered with the opening edge  6   b . When a state of surface of the collet chuck  3  is inferior, substantial electric connection cannot be obtained by reliably attracted contacts  60   a  and  60   b  with magnetic path. Thus, a circuit operation cannot be performed. In order to handle such case, a manual switch  83  is inserted between a cathode of the LED  34   a  of the base circuit and the common line  62 . Thus, the LED  34   a  can be electrically connected to the common line by the manual switch instead of the contacts  60   a  and  60   b  with magnetic path.  
         [0066]    An output of probe contact state from the one shot timer  73  which forms the lighting timer circuit is supplied to an LED of photocoupler  84 . A collector-emitter voltage of photo transistor which is urged by light emission of the LED can be detected at an exterior monitor terminal  85 . An added terminal  65 ′ is connected to the table side terminal  65  of the operating panel circuit ( 7 ). When a normal terminal  65  is in a state that a mounting screw is temporarily fastened in an initial setting for machine tool, the added terminal is effectively used when the adapter table  10  or a metallic work-piece supported by the adapter table  10  is not reliably electrically contacted.  
         [0067]    As shown in FIG. 13, a magnet contact  86  is connected to the added terminal  65 ′. An end surface of contact  86   a  with magnetic path is exposed from an opening surface of main body of the magnet contact  86 . A distal end lug portion  87   a  of lead wire  87  is screwed into the added terminal  65 ′. In this way, by the magnet contact  86  being magnetic attracted to the adapter table  10  or a metallic work-piece supported by the table  10 , the terminal is reliably electrically connected to such contacted object and an operation of operating panel circuit is ensured.  
         [0068]    [0068]FIGS. 14A through 14D show the respective portions and signal waveforms when the probe  4  fixed to the collet chuck  3  is contacted to the adapter table  10  of the present invention or the work-piece  8  supported by the table  10  for positioning, centering or scale correction. FIG. 14A shows a voltage level of signal of the check input terminal  70  from the contact detection circuit  69  to the noise limiter  71 . When the probe  4  does not contact, a collector of the transistor  66  in the circuit  69  is open. Thus, a voltage level of the terminal  70  is high (e.g., 5V) via a collector resistance. The voltage level is slightly linearly decreased for extremely short period of time by the probe  4  slightly contacting. Such slight decrease is ignored as a noise. The voltage level is in a “low” level which is equal to or lower than a threshold level S only when the probe  4  reliably contacts.  
         [0069]    An output of the schmitt trigger  72  which receives a noise limit signal of the noise limiter  71  generates a significant rectangular wave signal only during the aforementioned “low” level period, i.e., only when the probe contacts. Then, the LEDs  32   a  and  32   b  are lit (FIG. 14B) In contrast, the one shot timer  73  receiving an output of the schmitt trigger  72  generates an output which lasts for about 1 to 2 seconds not so as to miss lighting of the LEDs in a case that the probe contacts for a short time of period. Then, the LEDs  33   a  and  33   b  are lit at a recognizable time (FIG. 14C). The another one shot timer  78  which receives an output of the schmitt trigger  72  in parallel generates a sound from a buzzer or a speaker. Such sound is outputted for a short time of period, e.g., for 0.1 to 0.2 seconds or shorter because a notice of contact by the sound of the speaker  80  is easily recognized even for a short time of period and if the sound is heard for a long time of period, the sound is felt noisy (FIG. 14D).  
         [0070]    [0070]FIG. 15 shows an embodiment that the adapter table  10  further supports a stock vice  88 . The stock vice  88  is fixed by a bolt  89  being screwed into a T-shaped nut (not shown) which is engaged with the groove  30  of the table  10 . A work-piece  90  is further fixed to the stork vice and supported by the same. A combination of the adapter table  10  and the holder  9  (FIG. 1 and the like) can be changed and used depending on a work-piece or a purpose of machining.  
       ADVANTAGEOUS EFFECT OF THE INVENTION  
       [0071]    Because of the above-described constitution, the present invention exhibits the following effects.  
         [0072]    (1) As the adapter table of the present invention comprising a contact detection circuit is used, the number of exchanging a tool and a measurement tool such as a pin gauge can be reduced and the time required for preparing a machine tool can be shortened.  
         [0073]    (2) As well as the probe of the present invention, a pin gauge, a tool and a shank portion of the tool can be utilized as an electrode for contact detection. Unlike a conventional probe or gauge functional element, the probe according to be present invention can be immediately exchanged regardless of a shank diameter. Further, the probe of the present invention is not restricted by a size of the machine. A range of application can be extended.  
         [0074]    (3) The moment when the probe or tool serving as a contact detection electrode contacts a work-piece or a stock vice can be reliably recognized by a direct display LED and an extended display LED. Thus, attached matter or variation of center can be checked.  
         [0075]    (4) A voltage can be safely and reliably applied depending on a state at a time of detection, a tool or a material to be worked.  
         [0076]    (5) Extremely fine powder of work-piece attaches to a tool or a probe. Such attached matter becomes an obstacle especially when the probe is inserted into a small hole. The attached matter can be removed by discharge by extending an energizing time at a time of contact detection or increasing an energizing current. Alternatively, the attached matter can be melted or burn-out by using the clip electrode  12  shown in FIG. 4 while being brushed.  
         [0077]    (6) Conventionally, a distal end of tool rotating at high speed cannot be seen and thus the distal end strongly contacts the work-piece and damaged. The moment of contact can be reliably recognized by the direct display LED, the delayed display LED and a sound of buzzer. Thus, such damage can be prevented by controlling a movement of the tool or the table.  
         [0078]    (7) A state of contact of working tool can be similarly monitored. A height of Z axis, parallel, and a depth of engraving can be measured. Further, an abnormal situation can be overcome.