Patent Document

BACKGROUND OF THE INVENTION  
       [0001]     (1) Technical Field  
         [0002]     The present invention relates to an eyeglass lens processing apparatus for processing the eyeglass lenses.  
         [0003]     (2) Related Art  
         [0004]     In an eyeglass lens processing apparatus, each of the eyeglass lenses is held (chucked) between two lens chucking shafts and rotated, and a periphery of the lens is processed by a processing tool such as a grindstone so as to substantially fit a target lens shape. In the processing apparatus, a pair of lenses for right and left eyes are continuously processed in many cases. However, because the chucking shafts can hold only one lens, after one of the lenses has been processed, the lens must be removed from the chucking shafts, and the other lens must be held by the chucking shafts. This is annoying.  
       SUMMARY OF THE INVENTION  
       [0005]     A technical problem of the invention is to provide an eyeglass lens processing apparatus which can process the lenses efficiently with a simple structure.  
         [0006]     In order to solve the above described problem, the invention it characterized by comprising the following structures.  
         [0007]     (1) An eyeglass lens processing apparatus comprising:  
         [0008]     a processing tool that processes a periphery of an eyeglass lens;  
         [0009]     a lens chucking shaft that holds the eyeglass lens;  
         [0010]     a rotating unit that rotates the chucking shaft;  
         [0011]     a first moving unit that relatively moves the chucking shafts with respect to the processing tool;  
         [0012]     a lens holding arm that is provided with first and second lens holders for holding the lenses;  
         [0013]     a second moving unit that moves the lens holding arm; and  
         [0014]     a controller that controls the first and second moving units so that the first lens holder and the chucking shaft are moved to a first transfer position before and after the lens which is held by the first lens holder is processed, to transfer the lens therebetween, and, following the processing of the lens which is held by the first lens holder, the second lens holder and the chucking shaft are moved to a second transfer position, before and after the lens which is held by the second lens holder is processed, to transfer the lens therebetween.  
         [0015]     (2) The eyeglass lens processing apparatus according to (1), wherein the lens holding arm is an arm which is provided with the first lens holder and the second lens holder at respectively different positions.  
         [0016]     (3) The eyeglass lens processing apparatus according to (1), wherein the lens holding arm includes a first arm which is provided with the first lens holder, and a second arm which is provided with the second lens holder.  
         [0017]     (4) The eyeglass lens processing apparatus according to (1), wherein each of the first and second lens holders includes a resilient member for holding a cup which is attached to the lens by resilient force thereof, the resilient member having an engaging portion to be engaged with an aligning portion which is formed in the cup.  
         [0018]     (5) The eyeglass lens processing apparatus according to (4), wherein the controller controls the rotating unit to rotate the chucking shafts when the lenses held by the first and second lens holders are transferred.  
         [0019]     (6) The eyeglass lens processing apparatus according to (1) further comprising a mode selecting unit that selects a mode in which the lenses held by the first and second lens holders are continuously processed.  
         [0020]     (7) The eyeglass lens processing apparatus according to (1) further comprising:  
         [0021]     a processing chamber in which the chucking shafts and the processing tool are arranged; and  
         [0022]     an opening and closing cover for covering the processing chamber,  
         [0023]     wherein the second moving unit moves the lens holding arms so as to position the first and the second lens holders inside and outside the processing chamber, respectively, and  
         [0024]     the cover is opened and closed in association with the movement of the arm.  
         [0025]     (8) An eyeglass lens processing apparatus comprising:  
         [0026]     a processing tool that processes a periphery of an eyeglass lens;  
         [0027]     a lens chucking shaft that holds the lens;  
         [0028]     a rotating unit that rotates the chucking shaft;  
         [0029]     a first moving unit that relatively moves the chucking shaft with respect to the processing tool;  
         [0030]     a lens holding arm provided with first and second lens holders which hold the lenses;  
         [0031]     a second moving unit that moves the lens holding arm; and  
         [0032]     a controller that controls the second moving unit so that the first lens holder are moved to a first transfer position before and after the lens which is held by the first lens holder has been processed, to transfer the lens therebetween, and, following the processing of the lens which is held by the first lens holder, the second lens holder and the chucking shaft are moved to a second transfer position before and after the lens which is held by the second lens holder has been processed, to transfer the lens therebetween,  
         [0033]     wherein each of the first and second lens holders includes an elastic member for holding a cup which is attached to the lens by elastic force thereof, the elastic member having an engaging portion to be engaged with an aligning portion which is formed in the cup.  
         [0034]     (9) An eyeglass lens processing apparatus according to (8), wherein the controller controls the rotating unit to rotate the chucking shafts, when the lenses held by the first and second lens holders are transferred. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]      FIG. 1  is a schematic view showing an outer appearance of an eyeglass lens processing apparatus according to an embodiment of the invention.  
         [0036]      FIG. 2  is a schematic view showing a structure of a lens processing portion.  
         [0037]      FIG. 3  is a view showing an example of holding a lens by lens chucking shafts.  
         [0038]      FIG. 4  is a schematic view showing a structure of a cup to be attached to the lens.  
         [0039]      FIG. 5  is a schematic view showing a structure of a lens exchanging portion.  
         [0040]      FIG. 6  is a schematic view showing the structure of the lens exchanging portion.  
         [0041]      FIG. 7  is a schematic block diagram of a control system in the apparatus.  
         [0042]      FIG. 8  is a schematic view showing a modified structure of the lens exchanging portion.  
         [0043]      FIG. 9  is a view showing a modified example of holding the lens by the lens chucking shafts.  
         [0044]      FIG. 10  is a view showing a modified example of a lens holder. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0045]     Now, embodiments of the invention will be described referring to the drawings.  FIG. 1  is a schematic view showing an outer appearance of an eyeglass lens processing apparatus  1  in an embodiment of the invention. An eyeglass frame measuring device  2  is connected to the processing apparatus  1 . As the eyeglass frame measuring device  2 , those measuring devices as described in U.S. Pat. No. 5,333,412 (Japanese Patent Publication No JP-A-4-93164), U.S. Re. 35898 (Japanese Patent Publication No. JP-A-5-212661), for example, can be used. A display portion  415  for displaying processing data and so on, and a switch portion  420  having switches for inputting processing conditions or so and for giving processing instructions or so are provided at an upper part of the processing apparatus  1 . Lens to be processed is processed in a processing chamber  401  inside an opening and closing cover  402 . It is to be noted that the processing apparatus  1  may be integrally formed with the measuring device  2 .  
         [0046]      FIG. 2  is a schematic view showing a structure of a lens processing portion  200  which is arranged in a casing of the processing apparatus  1 . A lens LE to be processed is held (chucked) between lens chucking shafts  211 L and  211 R which are rotatably held by a carriage  210 , and is rotated so as to be ground by a grindstone  251 . The grindstone  251  in this embodiment includes a roughing grindstone  251   a  for glass, a roughing grindstone  251   b  for plastic, and a grindstone  251   c  for bevel-finishing and flat-finishing. A grindstone rotating shaft  250  to which the grindstone  251  is mounted is rotated by a grindstone rotating motor  253  through a rotation transmitting mechanism  252  which includes a pulley attached to a rotation shaft of the motor  253 , a belt and a pulley attached to the shaft  250 .  
         [0047]     The lens chucking shafts  211 L and  211 R are held by the carriage  210  in such a manner that their center axis (a rotation center axis of the lens LE) may be in parallel with a center axis of the shaft  250  (a rotation center axis of the grindstone  251 ). The carriage  210  can move in a direction of the center axis of the shaft  250  (a direction of the center axis of the chucking shafts  211 L and  211 R) (a direction of X), and also in a direction where an axis-to-axis distance between the center axis of the chucking shafts  211 L and  211 R and the center axis of the shaft  250  is varied (a direction of Y).  
         [0000]     &lt;Lens Holding (Chucking) Mechanism&gt; 
         [0048]     The chucking shaft  211 L is held on a left arm  210   a  of the carriage  210 , and the chucking shaft  211 R is held on a right arm  210   b  of the carriage  210 , rotatably and coaxially. A cup receiver  240  to which a cup  50  attached to the lens LE is mounted is fixed to a distal end of the chucking shaft  211 L, and a lens chucker  245  is fixed to a distal end of the chucking shaft  211 R (See  FIG. 3 ). A lens chucking motor  212  is fixed to the right arm  210   b . Rotation of the motor  212  is transmitted to the chucking shaft  211 R through a rotation transmitting mechanism (not shown) which includes a pulley attached to a rotation shaft of the motor  212 , a belt, and so on, and a rotation-rectilinear movement converting mechanism (not shown) which includes a ball screw, a nut, and so on, whereby the chucking shaft  211 R is moved in its axial direction. Along with this movement, the chucking shaft  211 R is moved in a direction of approaching the chucking shaft  211 L, and the lens LE is held (chucked) between the chucking shafts  211 L and  211 R.  
         [0000]     &lt;Lens Rotating Mechanism&gt; 
         [0049]     A lens rotating motor  215  is fixed to the left arm  210   a . Rotation of the motor  215  is transmitted to the chucking shaft  211 L through a rotation transmitting mechanism  214  which includes a gear attached to a rotation shaft of the motor  215 , a gear attached to the chucking shaft  211 L and so on, whereby the chucking shaft  211 L is rotated. The rotation of the motor  215  is also transmitted to the chucking shaft  211 R through a rotation transmitting mechanism (not shown) which includes a rotation shaft connected to the rotation shaft of the motor  215  and provided with a gear, a gear attached to the chucking shaft  211 R, and so on, whereby the chucking shaft  211 R is rotated. In this manner, both the chucking shafts  211 L and  211 R is synchronously rotated, and the lens LE which is held (chucked) between them is rotated.  
         [0000]     &lt;Moving Mechanism for the Carriage  210  in the X Direction&gt; 
         [0050]     Guide shafts  220   a  and  220   b  are fixed to a base  201  in parallel with each other, extending in the X direction, and a moving support base  221  is movably supported by the guide shafts  220   a  and  220   b . Moreover, the carriage  210  which is connected to the support base  221  is movably supported by the guide shaft  220   a . A motor  222  for movement in the X direction is fixed to the base  201 , and rotation of the motor  222  is transmitted to the support base  221  through a rotation-rectilinear movement converting mechanism  223  which includes a pinion gear attached to a rotation shaft of the motor  222 , a rack gear fixed to a rear part of the support base  221 , and so on, whereby the support base  221  is moved in the X direction. In this manner, the carriage  210  connected to the support base  221  is moved in the X direction.  
         [0000]     &lt;Moving Mechanism for the Carriage  210  in the Y Direction&gt; 
         [0051]     The carriage  210  is rotatably supported by the guide shaft  220   a . Moreover, a rotating support base  230  is rotatably mounted to the support base  221  so as to rotate around an axis consistent with the center axis of the shaft  250 . A motor  231  for movement in the Y direction is fixed to the support base  230 , and rotation of the motor  231  is transmitted to a ball screw  232  which is rotatably held on the support base  230 , through a rotation transmitting mechanism (not shown) which includes a pulley attached to a rotation shaft of the motor  231 , a belt and so on. Along with the rotation of the ball screw  232 , a moving support base  233  which is rotatably fitted to the left arm  210   a , and to which the ball screw  232  is screwed is moved along two guide shafts  235  which are fixed to the support base  230  in parallel with each other and extend in a direction perpendicular to the X direction. Accordingly, the carriage  210  which is connected to the support base  233  is moved (rotated) in the Y direction around the guide shaft  220   a . Further, a spring, which is not shown, is provided between the carriage  210  and the support base  221 , and the carriage  210  is always urged downwardly by the spring.  
         [0052]      FIG. 3  is a view showing how the lens LE is held between the chucking shafts  211 L and  211 R. In order to hold the lens LE between the chucking shafts  211 L and  211 R, the cup  50  is previously attached to a front refractive face of the lens LE by means of a double faced adhesive tape. The cup  50  has a base portion  51  to be inserted into an insertion hole  241  of the cup receiver  240 , and a flange portion  52  (See  FIG. 4 ). Moreover, a key groove  51   a  is formed in the base portion  51 . When this key groove  51   a  is engaged with a key  241   a  which is formed in the insertion hole  241 , the cup  50  which has been attached to the lens LE in a state where an astigmatic axis of the lens LE has been aligned in position (in direction) is mounted on the chucking shaft  211 L. Then, the chucking shaft  211 R is moved in the direction of approaching the chucking shaft  211 L, and the lens chucker  245  is butted against a rear refractive face of the lens LE, whereby the lens LE is held (chucked) between the chucking shafts  211 L and  211 R.  
         [0053]     The flange portion  52  of the cup  50  has an oval shape, and two projections  53  acting as alignment members are formed on an upper face of the flange portion  52 . The projections  53  are formed in a determined direction with respect to a direction of the key groove  51   a  (in a direction consistent with the direction of the key groove  51   a , in this embodiment), and in a determined positional relation (symmetrically with respect to a center axis of the cup  50 , in this embodiment). The projections  53  are provided for the purpose of being engaged with a cup detaching tool when the cup  50  is detached from the lens LE. However, the projections  53  also serve to hold the lens LE, when the lens LE is aligned in position and mounted on lens holders  530  and  540  in a lens exchanging portion  500 , which will be described below.  
         [0054]     A lens shape measuring portion  300  is arranged in a backward area of the carriage  210 .  
         [0055]      FIGS. 5 and 6  are schematic views showing a structure of the lens exchanging portion  500 .  FIG. 5  is a view in a state where the cover  402  is opened, as seen from a left side, and  FIG. 6  is a view in a state where the cover  402  is closed, as seen from the left side.  
         [0056]     A lens holding arm  510  is provided with the lens holder  530  which holds the lens LE for a left eye (hereinafter, referred to as a lens LE 1 ) and the lens holder  540  which holds the lens LE for a right eye (hereinafter, referred to as a lens LE 2 ). The holding arm  510  is fixed to a rotation shaft  511  which is rotatably held by the casing of the processing apparatus  1 . Moreover, an arm moving motor  501  is fixed to the casing of the processing apparatus  1 , and rotation of the motor  501  is transmitted to the rotation shaft  511  through a pulley  503  attached to a rotation shaft of the motor  501 , a belt  505 , and a pulley  513  attached to the rotation shaft  511 , whereby the rotation shaft  511  is rotated. Accordingly, the lens holding arm  510  is rotated.  
         [0057]     The holder  530  has a support member  531  fixed to the arm  510 , and two elastic members  533  in a form of springs or the like which are fixed to the support member  531 . The elastic members  533  are respectively formed with two recesses  533   a  opposed to each other, which are engaging portions to be engaged with the projections  53  of the cup  50 . When the lens LE 1  is mounted on the holder  530 , the projections  53  of the cup  50  attached to the lens LE are engaged with the recesses  533   a , and the cup  50  is held by elastic forces of the elastic members  533 , whereby the lens LE 1  is aligned in position and mounted on the holder  530 . A structure of the holder  540  is essentially the same as that of the holder  530 . The holder  540  has a support member  541  and two elastic members  543 , and the elastic members  543  are respectively formed with two recesses  543   a  opposed to each other.  
         [0058]     Installing positions of the holders  530  and  540  provided on the arm  510  are determined so that the center axes of the cups  50  attached to the lenses LE 1  and LE 2  may be positioned at positions YP 1  and YP 2  on a moving locus YP of the center axis of the chucking shafts  211 L and  211 R by the rotary movement of the carriage  210  (the chucking shafts  211 L and  211 R) in the Y direction, as shown in  FIG. 6 .  
         [0059]     Operation of the apparatus having the structure as described above will be explained, referring to the schematic block diagram of the control system in  FIG. 7 . As a first step, the cups  50  are respectively attached to a pair of the left and right lenses LE 1  and LE 2  using a known blocking device (cup attaching device). In case where the lens LE 1  and/or the lens LE 2  have an astigmatic axis, the cup  50  is attached so that the key groove  51   a  of the cup  50  may be consistent with a direction of the astigmatic axis. In this manner, a direction of the two projections  53  is also aligned with the direction of the astigmatic axis of the lens LE 1  and/or the lens LE 2 . An operator mounts and holds the lens LE 1  equipped with the cup  50 , on the holder  530 . On this occasion, the base portion  51  and the projections  53  of the cup  50  are entered between the elastic members  533 , as shown in  FIG. 5 , and the lens LE 1  is rotated thereby to allow the projections  53  to be engaged with the recesses  533   a . In this manner, the lens LE 1  is held by the elastic forces of the elastic members  533 . Moreover, by engaging the projections  53  with the recesses  533   a , the center axis of the cup  50  and the astigmatic axis of the lens LE 1  are aligned in position with respect to the holder  530  in a determined positional relation, and held. The other lens LE 2  is also mounted on the holder  540 , and held in the same manner.  
         [0060]     Before or after the above described operation, shapes of left and right rims of an eyeglass frame are measured by the measuring device  2 , and data of their target lens shapes is obtained. In case of a rimless frame or the like, a shape of a template and a shape of a dummy lens is measured, and data of its target lens shape is obtained. The data of the target lens shape obtained from the measuring device  2  is inputted into the processing apparatus  1  by switching a transfer switch in the switch portion  420 , and is stored in a memory  152 . When the data of the target lens shape has been inputted (stored), a figure of the target lens shape based on the target lens shape data is displayed on the display portion  415 . Then, the operator operates the switch portion  420  and inputs layout data such as an FPD (a distance between geometric centers of the left and right rims), a PD (a distance between pupils) of a wearer, a height of an optical center with respect to a geometric center of the target lens shape. In addition, the operator operates the switch portion  420 , and sets (input) material for the lens LE, a type of the eyeglass frame, processing mode, etc. By setting these processing conditions, processing steps is determined by the controller  150  based on a program which has been previously stored in the memory  153 .  
         [0061]     In case of continuously processing lenses by exchanging the lenses in the lens exchanging portion  500 , the operator operates a mode switch in the switch portion  420  to select a continuous processing mode. On the other hand, in case where the operator exchanges the lenses in a conventional manner, the operator operates the mode switch in the switch portion  420  to select a sole processing mode. A case where the continuous processing mode has been selected will be described below.  
         [0062]     When a processing starting switch in the switch portion  420  is pressed, the controller  150  controls the rotation of the motor  501  thereby to rotate the arm  510  in a direction of an arrow mark  502  (downward movement). In association with the downward movement of the arm  510 , the cover  402  is also rotated in the direction of the arrow mark  502  so as to be closed (downward movement) by urging force of a spring  403  (See  FIG. 1 ). The downward movement of the cover  402  is stopped at a position for keeping tight sealing, when a distal end of the cover  402  comes into contact with a restricting portion  101  (See  FIG. 6 ) which is formed in the casing of the processing apparatus  1 . The arm  510  is further rotated downwardly, and is stopped, when the center axis of the cup  50  attached to the lens LE 1  which is held by the holder  530  has arrived at the transfer position YP 1  of the lens LE 1 .  
         [0063]     Sequentially, the controller  150  controls the rotation of the motor  231  thereby to rotate the carriage  210  (the chucking shafts  211 L and  211 R) in the Y direction (downward movement), thereby allowing the center axes of the chucking shafts  211 L and  211 R to be positioned at the transfer position YP 1 . In order to position the chucking shafts  211 L and  211 R at the position YP 1 , the controller  150  keeps the chucking shafts  211 L and  211 R in an open position (an initial position). The controller  150  also controls the rotation of the motor  222  thereby to move the carriage  210  (the chucking shafts  211 L and  211 R) in the X direction, so that the lens LE 1  may be positioned between the cup receiver  240  and the lens chucker  245 . Moreover, the controller  150  controls the rotation of the motor  215  thereby to rotate the chucking shafts  211 L and  211 R, whereby the direction of the key  241   a  of the cup receiver  240  is made consistent with the direction of the key groove  51   a  of the cup  50  which is held by the holder  530 . In this state, the controller  150  controls the rotation of the motor  222  thereby to move the carriage  210  (the chucking shafts  211 L and  211 R) in the X direction, and stops the carriage  210  at a position where the base portion  51  of the cup  50  is inserted into the cup receiver  240 . At the same time, the controller  150  controls the rotation of the motor  212  thereby to move the chucking shafts  211 R in the direction of approaching the chucking shaft  211 L, thereby allowing the lens LE 1  to be held (chucked) between the chucking shafts  211 L and  211 R.  
         [0064]     Then, the controller  150  controls the rotation of the motor  215  thereby to rotate the chucking shafts  211 L and  211 R by a determined angle (for example, 90 degree) in a state where the lens LE 1  is held (chucked) between them. Along with this operation, the projections  53  of the cup  50  are disengaged from the recesses  533   a  of the holder  530 . Specifically, the projections  53  of the cup  50  are rotated against elastic forces of the elastic members  533 , and the lens LE 1  (the cup  50 ) is removed from the holder  530 , whereby transfer of the lens LE 1  to the chucking shafts  211 L and  211 R is completed.  
         [0065]     After the transfer of the lens LE 1  to the chucking shafts  211 L and  211 R has been completed, the controller  150  controls the rotation of the motor  501  thereby to rotate (upward movement) the arm  510  up to a retreat position in the processing chamber  401  which is shown by a dotted line in  FIGS. 5 and 6 . Moreover, the controller  150  calls up the target lens shape data and the layout data corresponding to the lens LE 1  which is held by the holder  530 , from the memory  152 , and actuates the shape measuring portion  300  according to these data, thereby to obtain the shapes (edge positions) of the front and back refractive faces of the lens LE 1 . Then, on the basis of the shapes of the lens and the target lens shape data which have been thus obtained, processing data is obtained. On the basis of the obtained processing data, the rotation of the chucking shafts  211 L and  211 R, and the movement of the carriage  210  (the chucking shafts  211 L and  211 R) are controlled, whereby the roughing is performed by the grindstones  251   a  or  251   b , and then, the finishing is performed by the grindstone  251   c.    
         [0066]     After the processing of the lens LE 1  has been finished, the controller  150  transfers the lens LE 1  which is held between the chucking shafts  211 L and  211 R to the holder  530 , in a reverse operation to the above described. Specifically, the controller  150  controls the rotation of the motor  231  to rotate the carriage  210  (the chucking shafts  211 L and  211 R) in the Y direction (upward movement), thereby allowing the center axes of the chuck shaft  211 L and  211 R to be positioned at the position YP 1 , and also controls the rotation of the motor  215  to rotate the chucking shafts  211 L and  211 R so that the base portion  51  and the projections  53  of the cup  50  may enter between the elastic members  533 . Then, the controller  150  controls the rotation of the motor  501  to move the arm  510  downwardly from the retreat position, thereby allowing the holder  530  to be positioned at the position YP 1 . When the rotation of the motor  215  is controlled to rotate the chucking shafts  211 L and  211 R by a determined angle (for example, 90 degree), the elastic members  533  are pressed with the rotation of the projections  53 , and the projections  53  are engaged with the recesses  533   a . Consequently, the lens LE 1  is again mounted on the holder  530  and held. Thereafter, the controller  150  controls the rotation of the motor  212  to move the chucking shafts  211 R in a direction of moving away from the chucking shaft  211 L, and controls the rotation of the motor  222  to move the carriage  210  (the chucking shafts  211 L and  211 R) in the X direction so as to move the chucking shaft  211 L in a direction of moving away from the cup  50 . In this manner, the lens LE 1  is released from the chucking shafts  211 L and  211 R, and the transfer of the lens LE 1  to the holder  530  is completed.  
         [0067]     Sequentially, the controller  150  moves the arm  510  downwardly, and stops the arm  510  when the center axis of the cup  50  attached to the lens LE 2  which is held by the holder  540  is positioned at the transfer position YP 2  of the lens LE 2 . The controller  150  moves the carriage  210  downwardly in the Y direction thereby to position the center axis of the chucking shafts  211 L and  211 R at the position YP 2 . Thereafter, in the same manner as the lens LE 1 , the lens LE 2  is transferred to the chucking shafts  211 L and  211 R.  
         [0068]     After the transfer of the lens LE 2  to the chucking shafts  211 L and  211 R has been completed, the controller  150  moves the arm  510  upwardly up to the retreat position, and calls up the target lens shape data and the layout data corresponding to the lens LE 2  which is held by the holder  540 , from the memory  152 . Then, the controller  150  actuates the measuring portion  300  according to these data, thereby to obtain the shapes (edge positions) of the front and back refractive faces of the lens LE 2 . Then, on the basis of the shapes of the lens and the target lens shape data which have been thus obtained, processing data is obtained. On the basis of the obtained processing data, the roughing and the finishing are conducted.  
         [0069]     After the processing of the lens LE 2  has been finished, transfer of the lens LE 2  to the holder  540  is conducted in the same manner as the lens LE 1 . After the transfer of the lens LE 2  to the holder  540  has been completed, the controller  150  controls the rotation of the motor  501  to move the arm  510  upwardly. When the arm  510  has moved upwardly beyond the retreat position in the processing chamber  401  to an outside of the processing chamber  401 , the cover  402  is moved so as to be opened, in association with the upward movement of the arm  510 . Finally, the arm  510  is opened to reach the position as shown in  FIG. 5 .  
         [0070]     As described above, the operator need not have the left and right lenses LE 1  and LE 2  respectively held by the chucking shafts  211 L and  211 R one by one, and therefore, processing efficiency of the operator is enhanced. For example, while the two lenses are being processed, other operations can be conducted. In the above described embodiment, as the mechanism for transferring the lens LE between the chucking shafts  211 L and  211 R and the holders  530  and  540 , the mechanism for moving the carriage  210  having the chucking shafts  211 L and  211 R in the X direction and Y direction is commonly used, and therefore, it is possible to move the arm  510  with the mechanism for moving in one direction. Moreover, as the mechanism for holding the lens LE by mounting it to the holder  530  or  540 , the elastic members ( 533  or the like) which hold the cup  50  attached to the lens LE are employed, and therefore, a driving mechanism for holding the lens LE can be omitted.  
         [0071]     As the lens processing portion (lens processing mechanism) in the processing apparatus  1 , it is possible to move the shaft  250  of the grindstone  251  in the X direction, instead of moving the carriage  210  (the chucking shafts  211 L and  211 R) in the X direction. In such a case too, it would be sufficient to provide a mechanism for moving the arm  510  or the holders  530  and  540  in the X direction, in addition to the rotary movement of the arm  510 . As for the movement of the chucking shafts  211 L and  211 R to the transfer positions YP 1  and YP 2 , the mechanism for moving the carriage  210  (the chucking shafts  211 L and  211 R) in the Y direction can be commonly used.  
         [0072]      FIG. 8  is a schematic view showing a modified structure of the lens exchanging portion. A lens exchanging portion  550  in this embodiment is different from the embodiment in  FIG. 5  in that a first lens holding arm provided with a lens holder and a second lens holding arm provided with a lens holder are provided so that two lenses can be moved independently.  
         [0073]     A first lens holding arm  560 L provided with a lens holder  570 L which holds the lens LE 1  is fixed to a rotation shaft  561 L which is rotatably held by the casing of the processing apparatus  1 . The rotation shaft  561 L is rotated by a motor  551 L through a rotation transmitting mechanism which is not shown. A structure of the lens holder  570 L is essentially the same as that of the holder  530 . The holder  570 L has a support member  571 L which is fixed to the arm  560 L, and two elastic members  573 L formed of springs or the like which are fixed to the support member  571 L. The elastic members  573 L are formed with two recesses  573 La opposed to each other, as the engaging portions to be engaged with the projections  53  of the cup  50 . On the other hand, a second lens holding arm  560 R provided with a lens holder  570 R which holds the lens LE 2  is fixed to a rotation shaft  561 R which is rotatably held by the casing of the processing apparatus  1 . The rotation shaft  561 R is rotated by a motor  551 R through a rotation transmitting mechanism which is not shown. A structure of the holder  570 R is essentially the same as that of the holder  570 L, and description of the same will be omitted.  
         [0074]     Installing position of the holder  570 L provided on the arm  560 L is set, as shown in  FIG. 8 , in such a manner that the center axis of the cup  50  attached to the lens LE 1  which is held may be positioned at a position XP 1  on a moving locus (the center axis) XP of the chucking shafts  211 L and  211 R, while the carriage  210  (the chucking shafts  211 L and  211 R) moves in the X direction. On the other hand, installing position of the holder  570 R provided on the arm  560 R is set in such a manner that the center axis of the cup  50  attached to the lens LE 2  which is held may be positioned at a position XP 2  on the moving locus XP.  
         [0075]     In the structure as described above, its operation will be described. The operator mounts the lenses LE 1  and LE 2  provided with the cups  50  respectively on the holders  570 L and  570 R to be held. On this occasion, in the same manner as described above, the projections  53  of the cups  50  are allowed to be engaged with the recesses  573 La and  573 Ra.  
         [0076]     When the processing starting switch has been pressed, the controller  150  controls the rotations of the respective motors to transfer the lens LE 1 . As a first step, the rotations of the motors  551 L and  551 R are controlled, whereby the first arm  560 L and the second arm  560 R are rotated to move (downward movements) up to the retreat position in the processing chamber  401 . In association with the downward movements of the first arm  560 L and the second arm  560 R, the cover  402  is also rotated so as to be closed (downward movement). The first arm  560 L is further rotated downwardly, and is stopped, when the center axis of the cup  50  attached to the lens LE 1  which is held by the holder  570 L has arrived at the transfer position XP 1  of the lens LE 1 . The controller  150  controls the rotation of the motor  215  thereby to rotate the chucking shafts  211 L and  211 R, so that the direction of the key  241   a  of the cup receiver  240  may be consistent with the direction of the key groove  51   a  of the cup  50 . In this state, the controller  150  controls the rotation of the motor  222  to move the carriage  210  (the chucking shafts  211 L and  211 R) in the X direction, and to stop the carriage  210  at a position where the base portion  51  of the cup  50  is to be inserted into the cup receiver  240 . At the same time, the controller  150  controls the rotation of the motor  212  to move the chucking shafts  211 R in the direction of approaching the chucking shaft  211 L, thereby allowing the lens LE 1  to be held (chucked) between the chucking shafts  211 L and  211 R. Thereafter, the lens LE 1  (the cup  50 ) is removed from the holder  570 L, by rotating the chucking shafts  211 L and  211 R by a determined angle, and the transfer of the lens LE 1  to the chucking shafts  211 L and  211 R is completed.  
         [0077]     After the processing for the lens LE 1  has been completed, the lens LE 1  which is held between the chucking shafts  211 L and  211 R is transferred to the holder  570 L. Then, the second arm  560 R is moved downwardly, and is stopped when the center axis of the cup  50  attached to the lens LE 2  which is held by the holder  570 R has arrived at the transfer position XP 2  of the lens LE 2 . On this occasion, because the position XP 2  is displaced from the position XP 1  by a determined amount in the X direction, when the lens LE 2  is transferred to the chucking shafts  211 L and  211 R, the movement of the carriage  210  (the chucking shafts  211 L and  211 R) in the X direction is controlled so that the transfer position may be changed by the amount of displacement. The transfer of the lens LE 2  is conducted essentially in the same manner as that of the lens LE 1 , and description of the same will be omitted.  
         [0078]     In this embodiment, as the mechanism for transferring the lens LE between the chucking shafts  211 L and  211 R and the holders  570 L and  570 R, the mechanism for moving the carriage  210  having the chucking shafts  211 L and  211 R in the X direction is commonly used. Therefore, it is needless to commonly use the mechanism for moving the carriage  210  in the Y direction. Moreover, the lens exchanging portion  550  in this embodiment can be also applied to such a structure that the grindstone  251  (the shaft  250 ) is adapted to move with respect to the lens LE (the chucking shafts  211 L and  211 R), instead of moving the lens LE (the chucking shafts  211 L and  211 R) with respect to the grindstone  251  (the shaft  250 ).  
         [0079]     Additionally, in the lens exchanging portion  550  in  FIG. 8 , it is possible to process a number of lenses continuously with a simple structure, because two lenses can be moved using separate lens holding arms. Specifically, after the lens LE 1  on the holder  570 L has been processed, another lens LE 1  is mounted and held on the holder  570 L, while the lens LE 2  on the holder  570 R is processed. Then, after the lens LE 2  on the holder  570 R has been processed, another lens LE 2  is mounted and held on the holder  570 R, while the other lens LE 1  on the holder  570 L is processed. By repeating this operation, it is possible to enhance processing efficiency of the apparatus, and a number of lenses can be efficiently processed. In this case, the cover  402  may be so constructed as not to be mechanically moved in association with the rotary movements of the arms  560 L and  560 R. For example, left and right covers may be separately opened and closed, or alternatively, the arms  560 L and  560 R may be moved outward from the processing chamber  401  in a state where the cover  402  is closed.  
         [0080]     Further, the lens exchanging portion  500  and the lens exchanging portion  550  may be combined. Specifically, two each of the holders  570 L and  570 R may be mounted on the first arm  560 L and the second arm  560 R in the lens exchanging portion  550 . Moreover, the number of the arms may be increased. By employing such structures, processing efficiency is further enhanced.  
         [0081]     Although, in the above described embodiment, the cup  50  is provided with the projections  53  which are the aligning portions when the lens LE is mounted on the holder  530  and so on, the invention is not limited to this embodiment. For example, as shown in  FIGS. 9 and 10 , it is possible to use a cup  60  having a key groove  61   a  which is formed up to nearly a root of a base portion  61 , as the aligning portion. In this case, a cup receiver  243  at the distal end of the chucking shaft  211 L may be provided with an insertion hole  243   a  into which the base portion  61  is inserted, a pin  243   b  to be engaged with the key groove  61   a , and springs  243   c  arranged in a bottom of the insertion hole  243   a . On the other hand, the elastic members  533  of the holder  530  may be formed with two convex portions  533   b  opposed to each other, as the engaging portions to be engaged with the key groove  61   a.    
         [0082]     When the cup  60  fixed to the lens LE is inserted into the cup receiver  243 , the carriage  210  (the chucking shafts  211 L and  211 R) is moved in the X direction until the key groove  61   a  is engaged with the pin  243   b , and the chucking shaft  211 R to which the lens chucker  245  is fixed is be moved in the direction of approaching the chucking shaft  211 L. On this occasion, the carriage  210  (the chucking shafts  211 L and  211 R) is moved in the X direction up to a position where the key groove  61   a  can be disengaged from the convex portions  533   b . Then, the chucking shafts  211 L and  211 R are rotated when the lens LE is held to a certain extent. In this manner, the key groove  61   a  of the cup  60  is disengaged from the convex portions  533   b . In short, the lens LE (the cup  60 ) is removed from the holder  530 . After the processing for the lens LE has been finished, the lens LE is transferred to the holder  530  in the reverse operations. On this occasion, as the chucking shaft  211 R is moved a little in the direction away from the chucking shaft  211 L, the cup  60  is also moved by spring force of the springs  243   c  in the cup receiver  243 , and a gap is formed so that the convex portions  533   b  can be engaged with the key groove  61   a . Thereafter, the holder  530  is moved to the determined transfer position, whereby the convex portions  533   b  are engaged with the key groove  61   a , thus enabling the lens LE to be transferred.  
         [0083]     As described above, various modifications can be added to the aligning portions, the engaging portions of the holders to be engaged with the aligning portions, and so on.  
         [0084]     Although the grindstone is employed as the processing tool in this embodiment, it is possible to employ known lens periphery processing tools such as a cutter, and an end mill.

Technology Category: b