BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an eyeglass lens processing apparatus for processing a periphery of an eyeglass lens.  
           [0002]    An eyeglass lens processing apparatus is known, which processes a periphery of an eyeglass lens using a grinding tool (such as a grinding stone and a machining cutter) so that the eyeglass lens is formed into a target lens shape (an eyeglass frame configuration or the like). In a case of a so-called two point frame (rimless glasses), a piercing is performed on the lens having been processed on the periphery. Conventionally, the piercing was manually practiced by an expert by use of a drilling machine. In this case, a hole direction is usually a normal direction at a hole position in a lens front surface.  
           [0003]    Further, there is also proposed an eyeglass lens processing apparatus equipped with a piercing mechanism, which sets a hole direction in a direction perpendicular with respect to a lens rotation axis.  
           [0004]    However, it is not easy to manually pierce the lens using the drilling machine or the like, and therefore a good piercing is difficult to an inexperienced operator.  
           [0005]    In case of the existing eyeglass lens processing apparatus equipped with the piercing mechanism, the piercing is done to a lens edge surface, and therefore an applicable two point frame is limited.  
           [0006]    An experienced expert sometimes adjusts a hole direction, taking a counteraction of the lens at forming a frame into consideration. This tendency is remarkable particularly in a case of a half-eye lens. This is because the hole direction gives large influences to finishing of the frame. However, since the conventional lens processing apparatus cannot change the hole direction, the frame cannot be finished into a desired configuration.  
         SUMMARY OF THE INVENTION  
         [0007]    In view of the above mentioned conventional technique, an object of the present invention is to provide an eyeglass lens processing apparatus, which can easily carry out a favorably piercing, and which has a great freedom in setting a hole direction.  
           [0008]    To achieve the object, the invention is characterized by providing the following structures.  
           [0009]    (1) An eyeglass lens processing apparatus for processing a periphery of an eyeglass lens, comprising:  
           [0010]    a lens rotation shaft which holds and rotates the lens, the shaft being rotatable about a first axis;  
           [0011]    a piercing tool which pierces a hole in the lens;  
           [0012]    a holder which rotatably holds the piercing tool; and  
           [0013]    inclination means for relatively inclining the holder with respect to the lens rotation shaft to change inclination of a rotation axis of the piercing tool with respect to the first axis.  
           [0014]    (2) The apparatus of (1), further comprising:  
           [0015]    control means for controlling rotation of the lens rotation shaft and inclination by the inclination means, based on piercing data including hole direction data.  
           [0016]    (3) The apparatus of (2), further comprising:  
           [0017]    first moving means for relatively moving the lens rotation shaft linearly in a direction of the first axis with respect to the piercing tool; and  
           [0018]    second moving means for relatively moving the lens rotation shaft linearly in a direction of a second axis perpendicular to the first axis or swingably to direct the first axis to the same direction, with respect to the piercing tool;  
           [0019]    wherein the control means controls movement by each of the first and second moving means, based on the piercing data including hole position data.  
           [0020]    (4) The apparatus of (3), wherein the inclination means includes rotation means for rotating the holder about a third axis perpendicular to the first axis, the rotation axis of the piercing tool being perpendicular to the third axis.  
           [0021]    (5) The apparatus of (3), further comprising:  
           [0022]    third moving means for moving the piercing tool between a piercing position and a retreat position,  
           [0023]    wherein the control means controls movement by the third moving means, based on the piercing data.  
           [0024]    (6) The apparatus of (5), wherein the third moving means moves the piercing tool linearly in a direction of the third axis.  
           [0025]    (7) The apparatus of (5), further comprising:  
           [0026]    protection means for protecting the piercing tool moved to the retreat position.  
           [0027]    (8) The apparatus of (3), further comprising:  
           [0028]    a grinding tool rotation shaft which holds and rotates a grinding tool for grinding the periphery of the lens, the grinding tool rotation shaft being rotatable about a fourth axis parallel to the first axis,  
           [0029]    wherein the first moving means relatively moves the lens rotation shaft linearly with respect to the grinding tool,  
           [0030]    wherein the second moving means relatively moves the lens rotation shaft linearly or swingably with respect to the grinding tool,  
           [0031]    wherein the control means control rotation of the lens rotation shaft and movement by the second moving means, based on periphery grinding data.  
           [0032]    (9) The apparatus of (2), further comprising:  
           [0033]    lens configuration measurement means for measuring a front surface configuration of the lens; and  
           [0034]    calculation means for obtaining a normal direction at a hole position in the lens front surface, based on the obtained configuration,  
           [0035]    wherein the hole direction data includes data on the obtained normal direction.  
           [0036]    (10) The apparatus of (1), wherein the holder holds at least one of a grooving grinding stone for forming a groove in an edge surface of the lens and a chamfering grinding stone for chamfering an edge corner of the lens to be rotatable coaxially with respect to the piercing tool.  
           [0037]    (11) The apparatus of (1), wherein the inclination means includes rotation means for rotating the holder about an axis perpendicular to the rotation axis of the piercing tool.  
           [0038]    (12) The apparatus of (1), further comprising:  
           [0039]    moving means for moving the piercing tool between a piercing position and a retreat position.  
           [0040]    (13) An eyeglass lens processing apparatus for processing a periphery of an eyeglass lens, comprising:  
           [0041]    a lens rotation shaft which holds and rotates the lens, the shaft being rotatable about a first axis;  
           [0042]    a piercing tool which pierces a hole in the lens; and  
           [0043]    a holder which rotatably holds the piercing tool,  
           [0044]    wherein the holder holds at least one of a grooving grinding stone for forming a groove in an edge surface of the lens and a chamfering grinding stone for chamfering an edge corner of the lens to be rotatable coaxially with respect to the piercing tool.  
           [0045]    The present disclosure relates to the subject matter contained in Japanese patent application No. P2001-343726 (filed on Nov. 18, 2001), which is expressly incorporated herein by reference in its entirety. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0046]    [0046]FIG. 1 is a schematic view showing an exterior structure of an eyeglass lens processing apparatus according to the present invention;  
         [0047]    [0047]FIG. 2 is a perspective view showing the schematic structure of a lens processing part disposed within a casing of a main body of the apparatus;  
         [0048]    [0048]FIG. 3 is a front view showing the schematic structure of a lens configuration measurement part;  
         [0049]    [0049]FIG. 4 is a perspective view showing the schematic structure of a piercing-chamfering-grooving mechanism part;  
         [0050]    [0050]FIGS. 5A and 5B are a front view and a left side view showing the schematic structure of the piercing-chamfering-grooving mechanism part;  
         [0051]    [0051]FIG. 6 is a cross sectional view showing the schematic structure of the piercing-chamfering-grooving mechanism part;  
         [0052]    [0052]FIG. 7 is a block diagram of a control system of the present apparatus;  
         [0053]    [0053]FIGS. 8A and 8B are views for explaining piercing.  
         [0054]    [0054]FIGS. 9A, 9B and  9 C are views for explaining the piercing;  
         [0055]    [0055]FIG. 10 is a view for explaining hole position data;  
         [0056]    [0056]FIGS. 11A and 11B are views for explaining the piercing in a normal direction in a lens front surface;  
         [0057]    [0057]FIG. 12 is a view for explaining grooving;  
         [0058]    [0058]FIG. 13 is a view for explaining that a spherical surface supposed from a curve of a grooving locus is obtained, and a rotation shaft of a grooving grinding stone is inclined in a normal direction at each processing point;  
         [0059]    [0059]FIG. 14 is a view showing a state in which a rotation part for piercing, chamfering and grooving is housed; and  
         [0060]    [0060]FIG. 15 is a view for explaining a plural-staged chamfering by changing a chamfering angle in plural stages. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0061]    Reference will be made to an embodiment of the invention with the attached drawings.  
         [0062]    (1) Overall Structure  
         [0063]    [0063]FIG. 1 is a schematic view showing an exterior structure of an eyeglass lens processing apparatus according to the invention. Numeral  1  designates a main body of the eyeglass lens processing apparatus, to which an eyeglass frame configuration measurement device  2  is connected. The eyeglass frame configuration measurement device  2  used in this apparatus is described, for example, in Patent Laid Open 5-212661 and Re. 35,898 (U.S. Pat. No. 5,347,762) assigned to the present assignee. The main body  1  has, in an upper part thereof, a display  415  for displaying processing data, etc., a switch panel  410  having various switches for inputting processing conditions, etc., and a switch panel  420  having various switches for instructions for processing. Numeral  402  designates an openable window for a processing chamber.  
         [0064]    [0064]FIG. 2 is a perspective view showing the schematic structure of a lens processing part to be installed within a casing of the main body  1 . A carriage part  700  is mounted on a base  10 , and a lens LE to be processed is held between lens rotation shafts (lens chuck shafts  702 L and  702 R) of a carriage  701 , and subjected to a grinding process by being pressure-contacted with grinding stone group  602  attached to a grinding stone-rotation shaft  601   a . The shafts  702 L and  702 R and the shaft  601   a  are arranged so that their rotation axes are in parallel to each other. Numeral  601  designates a grinding stone-rotation motor. The grinding stone group  602  comprises a rough grinding stone  602   a  for glasses, a rough grinding stone  602   b  for plastic and a finish grinding stone  602   c  for beveling and flat processing. Above the carriage  701 , lens configuration measurement parts  500  and  520  are disposed. At a rear side of the carriage part  700 , a piercing-chamfering-grooving mechanism part  800  is disposed.  
         [0065]    ( 2 ) Structure of Each of Parts  
         [0066]    (A) Carriage Part  
         [0067]    The structure of the carriage part  700  will be explained on the basis of FIG. 2. The shafts  702 L and  702 R can clamp the lens LE therebetween to rotate the lens LE. The carriage  701  is movable along carriage shafts  703  and  704  that are secured to the base  10  and that extend in parallel to the shaft  601   a.    
         [0068]    The carriage  701  is also movable to change an axis-to-axis distance between a rotation axis of the shafts  702 L and  702 R and a rotation axis of the shaft  601   a . In the following description, it is assumed that a direction in which the carriage  701  is linearly moved in parallel to the shaft  601   a  is an X axis direction (a rotation axis direction of the shafts  702 L and  702 R), while a direction in which the carriage  701  is linearly moved to change the axis-to-axis distance between the shafts  702 L and  702 R and the shaft  601   a  is an Y axis direction (an axis direction perpendicular to the X axis), and explanation will be made to the lens chuck mechanism, the lens rotation mechanism, and the X axis direction moving mechanism and the Y axis direction moving mechanism of the carriage  701 .  
         [0069]    &lt;Lens Chuck Mechanism and Lens Rotation Mechanism&gt; 
         [0070]    The shaft  702 L and the shaft  702 R is rotatably held, respectively, on a left arm  701 L of the carriage  701  and a right arm  701 R thereof to be coaxial with respect to each other. A chucking motor  710  is secured on a front portion of the right arm  701 R, and rotation of a pulley  711  mounted on the rotation shaft of the motor  710  is transmitted to a pulley  713  via a belt  712 , and the rotation thus transmitted is further transmitted to a feed screw and a feed nut (both not shown) rotatably held within the right arm  701 R. This causes the shaft  702 R to be moved in the rotation axis direction (the X axis direction), so that the lens LE is clamped by the shafts  702 L and  702 R.  
         [0071]    A lens rotating motor  720  is fixed on a left side end portion of the left arm  710 L. A gear  721  mounted on the rotation shaft of the motor  720  is in mesh with a gear  722 , a gear  723  coaxial with the gear  722  is in mesh with a gear  724 , and the gear  724  is in mesh with a gear  725  attached to the shaft  702 L. By this arrangement, the rotation of the motor  720  is transmitted to the shaft  702 L.  
         [0072]    The rotation of the motor  720  is transmitted to the right arm  701 R side via a rotation shaft  728  rotatably supported at the rear of the carriage  701 . The right arm  701 R is furnished at its right side end portion with similar gears as those of the left side end portion of the left arm  701 L (being the same as the gears  721  to  725  at the left side end portion of the left arm  701 L, detailed explanation will be omitted). By this arrangement, the shaft  702 L and the shaft  702 R are rotated in synchronization with each other.  
         [0073]    &lt;X Axis Direction Moving Mechanisms and Y Axis Direction Moving Mechanism of Carriage&gt; 
         [0074]    A moving support base  740  is attached to the shafts  703  and  704  so as to be movable in the axis direction thereof (in the X axis direction). The support base  740  is provided at its rear with a ball screw (not shown) attached thereto, which extends in parallel to the shaft  703 , and this ball screw is attached to the rotation shaft of an X axis moving motor  745  fixed to a base  10 . The rotation of the motor  745  is transmitted to the ball screw. By the rotation of the ball screw, the carriage  701  is linearly moved in the X axis direction together with the support base  740 .  
         [0075]    Shafts  756  and  757  extending in the Y axis direction are fixed to the support base  740 . The carriage  701  is attached to the shafts  756  and  757  so as to be movable in the Y axis direction. A Y axis moving motor  750  is fixed to the support base  740  by an attaching plate  751 . The rotation of themotor  750  is transmitted to a ball screw  755 , rotatably held by the attaching plate  751 , via a pulley  752  and a belt  753 . By the rotation of the ball screw  755 , the carriage  701  is linearly moved in the Y axis direction (to change the axis-to-axis distance between the shafts  702 L and  702 R and the shaft  601   a ).  
         [0076]    (B) Lens Configuration Measurement Part  
         [0077]    [0077]FIG. 3 is a view for explaining the schematic structure of a lens configuration measurement part  500  for a lens rear surface (lens rear side refractive surface). A support base  501  is fixed to a support base block  100  fixedly provided on the base  10  (see FIG. 2), and a slider  503  is slidably attached onto a rail  502  fixed to the support base  501 . A slide base  510  is fixed to the slider  503 , and a feeler arm  504  is fixed to the slide base  510 . A ball bush  508  is fitted to the side surface of the support base  501  so as to eliminate rattling of the feeler arm  504 . An L-shaped feeler hand  505  is fixed to the leading end portion of the arm  504 , and a feeler  506  in the form of a circular plate is attached to the leading end portion of the hand  505 . For measuring the lens configuration, the feeler  506  is brought into contact with the rear surface of the lens LE.  
         [0078]    A rack  511  is fixed to the lower end portion of the slide base  510 . The rack  511  is in mesh with a pinion  512  of an encoder  513  fixed to the support base  501 . The rotation of the motor  516  is transmitted to the rack  511  via a gear  515  attached to the rotation shaft of the motor  516 , an idle gear  514  and the pinion  512  so that the slide base  510  is moved in the X axis direction. During measurement of the lens configuration, the motor  516  pushes the feeler  506  against the lens LE at constant force. The encoder  513  detects a moving amount of the slide base  510  (i.e. a moving amount of the feeler  506 ) in the X axis direction. By the information of this moving amount and the rotation angle of the shafts  702 L and  702 R, the rear surface configuration of the lens LE is measured.  
         [0079]    As a lens configuration measurement part  520  for a lens front surface (a lens front side refractive surface) is symmetrical with respect to the lens configuration measurement part  500 , explanation for the structure is omitted.  
         [0080]    (C) Piercing-Chamfering-Grooving Mechanism Part  
         [0081]    Explanation will be made to a schematic structure of the piercing-chamfering-grooving mechanism part  800  on the basis of FIGS.  4  to  6 . FIG. 4 is a three-dimensional view of the mechanism part  800 , FIG. 5A is a left side view, FIG. 5B is a front view, and FIG. 6 is an A-A cross sectional view of FIG. 5B.  
         [0082]    A fixing plate  801  serving as a base of the mechanism part  800  is fixed to the block  100 . A rail  802  extending in a Z axis direction (which is an axis direction perpendicular to at least the X axis, and in this embodiment, an axis direction perpendicular with respect to an X-Y axes plane) is fixed to the fixing plate  801 , and a slider  803  is slidably mounted on the rail  802 . A moving support base  804  is fixed to the slider  803 . The support base  804  is linearly moved in the Z axis direction by a motor  805  rotating a ball screw  806 .  
         [0083]    A rotating support base  810  is rotatably supported by bearings  811  onto the support base  804 . The two bearings  811  are used, and a spacer  812  is disposed to keep a distance therebetween. At one side of the bearing  811 , a gear  813  is fixed to the support base  810 . The gear  813  is in mesh with an idle gear  614 , which is, in turn, in mesh with a gear  815  fixed to the rotation shaft of the motor  816  fixed to the support base  804  via an idle gear  814 . By this arrangement, the support base  810  is rotated about an axis of the bearings  811  when the motor  816  is rotated.  
         [0084]    A rotation part  830  holding a piercing drill  835  and a grinding stone portion  836  is attached to the leading end portion of the support base  810 . A pulley  832  is attached to a center portion of a rotation shaft  831  of the rotation part  830 , and the shaft  831  is rotatably supported by two bearings  834 . The drill  835  is attached to one end of the shaft  831  by a chuck mechanism  837 , and a spacer  838  and the grinding stone portion  836  is attached to the other end of the shaft  831  by a nut  839 . The grinding stone portion  836  is constructed by a chamfering grinding stone  836   a  and a grooving grinding stone  836   b  formed integrally with each other. The diameter of the grooving grinding stone  836   b  is about 15 mm, and the chamfering grinding stone  836   a  has an oblique processing surface in conical shape reducing in diameter from the grooving grinding stone  836   a  toward the leading end side. The chamfering grinding stone  836   a  may be cylindrical.  
         [0085]    A motor  840  for rotating the shaft  831  is fixed to an attaching plate  841  attached to the support base  810 . A pulley  843  is attached to the rotation shaft of the motor  840 . A belt  833  is suspended between the pulley  832  and the pulley  843  within the support base  810 , for transmitting the rotation of the motor  840  to the shaft  831 .  
         [0086]    Next, the operation of the apparatus having the above mentioned structure will be explained by use of a control system block diagram of FIG. 7. Here, the piercing and the grooving will be mainly discussed.  
         [0087]    First of all, a target lens shape (an eyeglass frame configuration) is measured by the eyeglass frame measurement device  2 . In a case of the rimless frame, the target lens shape is obtained from a template or a dummy lens. The obtained target lens shape data are input into a data memory  161  by pushing a switch  421 . The display  415  displays a figure based on the target lens shape, and the apparatus is ready for inputting the processing conditions, etc. An operator operates the respective switches on the switch panel  410  to input necessary layout data such as a PD of a wearer or a height of an optical center, and to input material of the lens LE to be processed and a processing mode. In case that the piercing is to be executed, a piercing mode is selected by a switch  422 . In case that the grooving is to be executed, a grooving mode is selected by a switch  423 . In case that the chamfering is to be executed, a switch  424  is operated to select a chamfering mode.  
         [0088]    When a necessary input is complete, the lens LE is clamped by and between the shafts  702 L and  702 R, and thereafter a start switch  425  is pushed to operate the apparatus. A main control part  160  obtains a radius vector data about a processing center on the basis of the input target lens shape data and layout data, thereafter obtains processing data (periphery grinding data) from positional data of a contact point where each radius vector contacts the grinding stone, and stores those data in a memory  161 .  
         [0089]    Subsequently, in accordance with a process sequence program, the main control part  160  measures the lens configuration using the lens configuration measurement parts  500  and  520 . The main control part  160  drives the motor  516  to move the feeler arm  504  in the X axis direction from a retreat position to a measuring position. The main control part  160  moves the carriage  701  in the Y axis direction by driving the motor  750  on the basis of the radius vector data. The main control part  160  drives the motor  516  to move the arm  504  (to push the arm  504  at a slight force) in the X axis direction so that the feeler  506  constantly contacts the rear surface of the lens LE.  
         [0090]    Under the condition where the feeler  506  contacts the rear surface of the lens LE, the main control part  160  drives the motor  720  to rotate the shafts  702 L and  702 R (the lens LE). Concurrently, the main control part  160  drives the motor  750  on the basis of the radius vector data so as to move the carriage  701  in the Y axis direction (vertically). The feeler  506  is moved in the X axis direction (laterally) along the rear surface configuration of the lens LE in conjunction with the rotation of the lens LE and the movement of the carriage  701 . The moving amount is detected by the encoder  513 , so that the rear surface configuration of the lens LE is measured. After the measurement of the lens rear surface configuration is complete, the main control part  160  drives the motor  516  to move the arm  504  in the X axis direction and position the arm  504  at the retreat position.  
         [0091]    Similarly, the front surface configuration of the lens LE is measured by the lens configuration measurement part  520 . When the front and rear surface configurations of the lens LE are obtained, lens edge thickness data can be obtained from both of the configurations.  
         [0092]    After the measurement of the lens configuration is complete, the main control part  160  processes the lens LE based on the processing data. The main control part  160  drives the motor  745  to move the carriage  701  in the X axis direction so as to position the lens LE above the rough grinding stone  602   b  (or the rough grinding stone  602   a ), and thereafter drives the motor  750  to move the carriage  701  in the Y axis direction (vertically), thereby carrying out the rough processing. Subsequently, the carriage  701  is moved in the X axis direction so that the lens LE is moved to a flat part of the finish grinding stone  602   c , and similarly the carriage  701  is moved in the Y axis direction to carry out the finish processing.  
         [0093]    In case that the piercing is to be carried out, the piercing-chamfering-grooving mechanism part  800  is used after the finish processing.  
         [0094]    The piercing will be explained. FIG. 8A is an example in which the piercing is executed in a direction parallel to the shafts  702 L and  702 R (in the X axis direction). In this case, the main control part  160  drives the motor  816  to rotate the support base  810  so that the shaft  831  of the drill  835  is positioned in parallel to the shafts  702 L and  702 R. The leading end of the drill  835  is positioned to a hole position P 1  of the lens LE by movement of the carriage  701  in the X axis direction by the motor  745 , movement of the carriage  701  in the Y axis direction by the motor  750 , movement of the drill  835  (the rotation part  830 ) in the Z axis direction by the motor  805  and rotation of the shafts  702 L and  702 R by the motor  720 . Subsequently, the drill  835  (the shaft  831 ) is rotated by the motor  840 , and the motor  745  is driven to move the carriage  701  in the X axis direction to thereby move the lens LE toward the drill  835 . The piercing is carried out in this manner.  
         [0095]    The data on the hole position P 1  is in advance input by operating the switches on the switch panel  420 , and stored in the memory  161 . The data on the hole position P 1  is, for example as shown in FIG. 10, measured as a polar coordinate (Δθ, Δd) with respect to a geometrical center O of the target lens shape (or the optical center of the lens LE). A reference for Δθ is defined as a horizontal direction H under a condition in which the lens LE is mounted to the eyeglass frame. The positional data may be a rectangular coordinate system. The main control part  160  converts the data on the hole position P 1  into the respectively directional data of the X, Y, and Z axes, and positions the leading end of the drill  835  at the hole position PI based on the obtained data.  
         [0096]    The piercing can be performed in an arbitrary direction in the lens LE in a manner as follows. In this case, the arranging angle of the lens LE is changed by rotating the shafts  702 L and  702 R in accordance with the hole direction. For example, FIG. 9A shows a case where the lens LE is rotated such that the horizontal direction H of the lens LE is coincident with the Y axis direction. Under this condition, if the shaft  831  of the drill  835  is, as shown in FIG. 8B, inclined by an angle al with respect to the X axis direction using the motor  816 , it is possible to obtain (form) a hole inclined by the angle al in the same direction as the horizontal direction H of the lens LE.  
         [0097]    [0097]FIG. 9B shows a case where the lens LE is rotated such that the horizontal direction H of the lens LE is coincident with the Z axis direction. Under this condition, if the shaft  831  of the drill  835  is inclined by an angle α1 with respect to the X axis direction, it is possible to obtain (form) a hole inclined by the angle α1 in the direction perpendicular to the horizontal direction H of the lens LE.  
         [0098]    [0098]FIG. 9C shows a case where the lens LE shown in FIG. 9A &#39;s rotated counterclockwise by an angle θ1. Under this condition, if the shaft  831  of the drill  835  is inclined by an angle al with respect to the X axis direction, it is possible to obtain (form) a hole inclined by the angle α1 in the rotation angle θ 1  direction of the lens LE. In addition, the case of FIG. 9B corresponds to a situation in which the lens LE shown in FIG. 9A is rotated counterclockwise by θ1=90°.  
         [0099]    That is, the hole direction can be managed by the inclined angle α1 of the shaft  831  of the drill  835  and by the rotation angle θ1 of the lens LE. The data on the hole direction are also preliminarily input by operating the switches on the switch panel  420 , and stored in the memory  161 . In addition, as the piercing data (the hole position data and the hole direction data), it is possible to use designing data of a two point frame, which may be obtained and input to the apparatus using a communications system such as a personal computer.  
         [0100]    When piercing, the main control part  160  controls, on the basis of the hole direction data, the rotation angle θ1 of the lens LE (the shafts  702 L and  702 R) by the motor  720  and the inclined angle α1 of the shaft  831  of the drill  835  by the motor  816 . The main control part  160  positions the leading end of the drill  835  at the hole position P 1  of the lens LE on the basis of the hole position P 1  data by the movement of the carriage  701  in the X axis direction by the motor  745 , the movement of the carriage  701  in the Y axis direction by the motor  750 , and the movement of the drill  835  (the rotation part  830 ) in the Z axis direction by the motor  805 . Subsequently, the drill  835  (the shaft  831 ) is rotated by the motor  840 , and the carriage  701  is moved in the X axis direction by the motor  745  and in the Y axis direction by the motor  750 , so that the piercing is carried out. That is, the piercing is carried out by moving the lens LE in the rotation axis direction of the shaft  831  (the direction of the inclination angle α1) by the movement of the carriage  701  in the X axis and Y axis directions.  
         [0101]    Since the present embodiment employs a mechanism in which the carriage  701  is linearly moved in the Y axis direction, the control of the piercing is easier than a mechanism in which the carriage  701  is swingably moved so that the shafts  702 L and  702 R are always in parallel to the shaft  601   a  (see, for example, Japanese patent laid open 5-212661, and Re. 35,898 (U.S. Pat. No. 5,347,762)). Of course, the present invention can be applied to the mechanism in which the carriage  701  is swingably moved.  
         [0102]    Next, the piercing in the normal direction of the Lens front surface will be explained. In this case, as shown in FIG. 11, point Q 1 , Q 2 , Q 3 , and Q 4  (at least three points) around the hole position P 1  are measured by the lens configuration measurement part  520 . From the measured results, a tangential plane S at the hole position P 1  is approximately derived, and the normal direction is calculated as a vertical direction of the tangential plane S at the hole position P 1  (see FIG. 11B). The data on the calculated normal direction are stored in the memory  161 .  
         [0103]    If the lens front surface configuration is preliminarily known, the data are input via a communications system, and the normal direction can be calculated based on the input data and the hole position P 1  data. When piercing, the inclined angle α1 of the shaft  831  of the drill  835  and the rotation angle θ1 of the lens LE are controlled on the basis of the normal direction data. The leading end of the drill  835  is positioned at the hole position P 1  of the lens LE, and then the lens LE is moved by the movement of the carriage  701  in the X axis and Y axis directions, whereby the piercing is carried out at the hole position P 1  of the lens LE in the normal direction.  
         [0104]    Using the piercing method as mentioned above, if the drill  835  is changed to an end mill, it is possible to apply a milling process, a process of forming an elongated hole or the like to the lens LE. For example, in the case of forming the elongated hole, the carriage  701  is moved in the X axis and Y axis directions or the rotation part  830  of the end mill is moved in the Z axis direction, in conformity with an elongating axis direction of the elongated hole during processing the lens LE, thereby forming the elongated hole.  
         [0105]    During grinding the lens LE with the grinding stone group  602 , since glass broken pieces are scattered in the processing chamber, the drill  835  (the rotation part  830 ) is desirably protected. To this end, as shown in FIG. 14, a recess like housing part  900  is provided in a wall of the processing chamber for storing the rotation part  300  moved in the Z axis direction to the retreat position.  
         [0106]    Next, the grooving will be explained. The main control part  160  positions the lens LE above the grooving grinding stone  836   b  as shown in FIG. 12 by the movement the carriage  701  in the X axis direction by the motor  745 , the movement of the carriage  701  in the Y axis direction by the motor  750 , the movement of the grooving grinding stone  836   b  (the rotation part  830 ) in the Z axis direction by the motor  805 , and the rotation of the grooving grinding stone  836   b  (the rotation part  830 ) by the motor  816 .  
         [0107]    The main control part  160  controls, based on grooving data, the movement of the carriage  701 , the rotation of the lens LE, and the inclination angle β of the shaft  831  of the grooving grinding stone  836   b.    
         [0108]    The grooving data are in advance obtained by the main control part  160  from the radius vector data of the lens LE and the measured result of the lens configuration. The control of the movement of the carriage in the X axis direction and in the Y axis direction is executed on the basis of grooving locus data. The grooving locus data is indicative of a locus of a groove formed in the edge surface of the lens LE, and is expressed by radius vector data (angle and length of the radius vector) obtained from the target lens shape by taking the groove depth into consideration, and positional data in the X axis direction. Since the lens edge thickness is obtained from the measurement data of the lens configuration, the positional data in the X axis direction can be determined based on the edge thickness in the same manner as the method of determining the bevel position. For example, various methods can be used, which include, but not limited to, a method of setting a groove position at a position obtained by dividing the lens edge thickness at a certain ratio, and a method of setting the groove position at a position shifted from the edge position on the lens front surface toward the lens rear surface by a constant amount so that the groove extends along the lens front surface curve.  
         [0109]    Herein, if the grooving is performed on the entire periphery of the lens LE-with the inclination angle β of the shaft  831  of the grooving grinding stone  836   b  being fixed, the groove width will be partially widened. Therefore, a countermeasure is prepared as follows. As shown in FIG. 13, a spherical surface supposed from a curve of the grooving locus is obtained, and a normal direction at each processing point of the grooving locus is obtained. N 1  and N 2  of FIG. 13 respectively show normal directions of processing points K 1  and K 2 . By inclining the shaft  831  of the grooving grinding stone  836   b  in the normal direction, the data on the inclination angle β of the shaft  831  of the grooving grinding stone  836   b  can be obtained correspondingly to the radius vector angle of each processing point. Under a condition where an outer circumference of the grinding stone contacts the spherical surface supposed from the curve of the grooving locus entirely, each processing point is obtained by effecting a grinding stone diameter correction (see, for example, Japanese patent laid open 5-212661 and Re. 35,898 (U.S. Pat. No. 5,347,762)) three-dimensionally. This makes it possible to suppress the widening of the groove width.  
         [0110]    The movement position of the grooving grinding stone  836   b  in the Z axis direction in FIG. 13 represents a case in which the shaft  831  of the grooving grinding store  836   b  is positioned on the X and Y axes plane where the shaft  702 L and  702 R are moved on the assumption that a center of the spherical surface supposed from the curve of the grooving locus is positioned on the shafts  702 L and  702 R. In a case in which the center of the spherical surface supposed from the curve of the grooving locus is offset from the shafts  702 L and  702 R, the motor  805  is driven under such a control that the movement position of the grooving grinding stone  836   b  in the Z axis direction is changed in response to the offset amount. This makes it possible to suppress the widening of the groove width  
         [0111]    Further, if the outer diameter of the grooving grinding stone is too large, the groove is likely to be widened in comparison to the width of the grooving grinding stone. In the present apparatus, the outer diameter of the grooving grinding stone  836   b  is around 15 mm, so that it is possible to prevent the groove from being widened in comparison to the width of the grooving grinding stone.  
         [0112]    The grooving is carried out by changing the inclination angle β of the grooving grinding stone  836   b  at each processing point, while pressure-contacting the rotated lens LE with the rotated grooving grinding stone  836   b  by the linear movement of the carriage  701  in the X axis and Y axis directions. Similarly to the piercing, the mechanism in which the carriage  701  is swingably moved may be employed.  
         [0113]    In a case where the chamfering mode is set, the main control part  160  moves and controls, after the completion of the piercing or the grooving, the carriage  701  and the piercing-chamfering-grooving mechanism part  800  on the basis of the chamfering data to execute the chamfering. During the chamfering, the chamfering grinding stone  836   a  of the grinding stone  836  is contacted with the corner of the edge of the lens LE to grind the edge corner. Also in this chamfering, the inclination angle β of the shaft  831  of the chamfering grinding stone  836   a  can be changed, and therefore it is possible to set a chamfering angle to be processed to the edge corner of the lens LE in an arbitrarily manner. Further, as shown in FIG. 15, the processing surface of the chamfering grinding stone  836   a  can be inclined at angles M 1 , M 2 , and M 3  to change the chamfering angle in plural steps, thereby forming a chamfered surface made up of plural staged slope parts at the edge corner of the same radius vector angle.  
         [0114]    During the chamfering, the chamfering grinding stone  836   a  is arranged at the same processing position as the grooving, and the inclination angle β of the shaft  831  is controlled in accordance with the set chamfering angle. The position of the edge corner of the lens LE can be obtained from the measurement of the lens configuration based on the target lens shape. The respective processing data are calculated correspondingly to the angles M 1 , M 2  and M 3  at which the processing surface of the chamfering grinding stone  836   a  is inclined, and in accordance with the processing data, the movement of the carriage  701  in the X axis direction or the Y axis direction is controlled. In a case where the plural staged slope parts are to be formed, the lens LE is rotated at each of the set angles. Using the formation of such plural staged slope parts, the lens edge corners can be finished to provide a design.  
         [0115]    The embodiment as mentioned above have been made to the apparatus of a type in which the carriage  701  having the shafts  702 L and  702 R for clamping and rotating the lens LE is moved in the X axis and Y axis directions, but the present invention can be applied to an apparatus of such a type as disclosed in Patent Laid Open 9-253999 and U.S. Pat. No. 5,716,256, in which the grinding stone side for processing the periphery is moved in the X axis and Y axis directions. In such an apparatus, since the lens LE is not moved in the X axis and Y axis directions, the apparatus is arranged to have a moving mechanism for relatively moving the piercing-chamfering-grooving mechanism part  800  side in the X axis and Y axis directions.  
         [0116]    Further, it is not essential to perform the movement of the rotation part  830  in the Z axis direction as the linear movement.  
         [0117]    That is, similarly to the carriage  701 , the movement of the rotation part  830  may be a swingable movement (Note that the linear movement is preferably in view of ease of control). Moreover, if the shafts  702 L and  702 R, the shaft  601   a  and the shaft  831  are disposed in parallel to the same plane, the moving mechanism for the rotation part  830  in the Z axis direction can be dispensed with.  
         [0118]    As mentioned above, according to the invention, it is possible to easily carry out the good piercing, irrespective of a worker&#39;s skillfulness. As the hole direction can be determined freely, it is possible to take into consideration a counteraction of the lens when making the frame.
An eyeglass lens processing apparatus for processing a periphery of an eyeglass lens, includes: a lens rotation shaft which holds and rotates the lens, the shaft being rotatable about a first axis; a piercing tool which pierces a hole in the lens; a holder which rotatably holds the piercing tool; and inclination means for relatively inclining the holder with respect to the lens rotation shaft to change inclination of a rotation axis of the piercing tool with respect to the first axis.