Abstract:
An end face polishing apparatus has a jig plate for supporting at least one workpiece having an end face and a polishing plate mounted for undergoing movement. A polishing member is mounted on the polishing plate for undergoing movement therewith to polish the end face of the workpiece. A slidable contact member is disposed on the jig plate for slidable contact with the polishing plate during a polishing operation to thereby regulate a polishing amount of the end face of the workpiece.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application is a divisional of U.S. application Ser. No. 09/783,878 filed on Feb. 15, 2001 now U.S. Pat. No. 6,800,021 and claiming a priority date of Mar. 13, 2000. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an end face polishing apparatus for polishing end faces of rod-shaped members of optical communication fibers and the like. 
   2. Description of the Related Art 
   An optical communication fiber is used after it has been adhered and fixed to a center hole of a ferrule which is a main member of a connector, and then an end face of the ferrule and an end face of a fiber are simultaneously smoothly polished to become a mirror surface. If the polished surfaces of the ferrule and the fiber thus polished are not vertical to a center axis of the ferrule, or the polished surfaces have damages, the optical connector having ferrules oppositely connected with each other is deteriorated in accuracy at the opposite position, resulting in an increase in loss. Therefore, the polished surface of a ferrule including an optical fiber requires finishing of the polished surface with high accuracy. 
   As a conventional optical fiber end face polishing apparatus, for example, there is one disclosed in Japanese Patent Application Laid-open No. Hei 3-26456. The optical fiber end face polishing apparatus disclosed in this publication has an eccentric plate which rotates on a concentric circle of a self-rotation disc, and has a planetary gear which transmits rotation of a motor for revolution to this eccentric plate, and these are combined with a polishing plate to cause the polishing plate to self-rotate and revolve. The plurality of the end-faces of the ferrule held by a jig plate are pressed to the polishing member fixed to the polishing plate and polished. 
   As described above, the conventional optical fiber end-face polishing apparatus conducts polishing by pressing the end faces of a plurality of ferrules with spring and the like held by the jig plate to the polishing member fixed to the rotating and revolving polishing plate. However, polishing of the rod-shaped member is adjusted by time, so that the polishing length of the rod-shaped member cannot be adjusted. Further, there is no problem if the lengths of the ferrules mounted on the jig plate are all the same, but from reasons that adhesives for fixing the ferrule accuracy and optical fiber flow out from the tip end of the ferrule and harden, the lengths of the respective ferrules differ. Therefore, if the ferrules differing in lengths are made to slidably contact the polishing plate, the jig plate tilts to the polishing plate, thereby causing variation in polishing angle, radius of curvature and eccentricity. Further, there is a problem that variation inferrule lengths occur after polishing. 
   The object of the present invention in view of the above, is to provide an end face polishing apparatus improved in polishing accuracy regardless of the length of the ferrule when polishing the end faces of the ferrule. 
   To solve the above objects, according to a first aspect of the present invention, an end face polishing apparatus in which a rod-shaped member mounted on a jig plate by a polishing member mounted on the polishing plate which is rotatably and swingably supported to the apparatus body is pressed to be polished is characterized in that, the jig plate is provided on either the jig plate or the polishing plate, and the other is slidably contacted by a slidable contact member, and is supported in a state where rotation is regulated on the polishing plate. 
   According to a second aspect of the present invention, in a first aspect of the invention, an end face polishing apparatus is characterized in that the length in the axial direction of the rod-shaped member protruding from the lower end face of the jig plate is longer than the height of the slidable contact member. 
   According to a third aspect of the present invention, in the first or second aspect, an end face polishing apparatus is characterized in that the jig plate is held by biasing in the polishing plate direction by the support mechanism where the jig plate is provided on the apparatus body. 
   According to a fourth aspect of the present invention, in any one of the first to third aspects, an end face polishing apparatus is characterized in that the jig plate comprises an adjusting mechanism for adjusting the height of the polishing member. 
   In the end face polishing apparatus of the present invention, by providing a slidable contact portion on either the jig plate or the polishing plate to slidably contact the other with a low friction, the jig plate can be maintained horizontal to the polishing plate, thereby improving the polishing accuracy of the rod-shaped member. Further, the length of the rod-shaped members may be made uniform. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
       FIGS. 1A and 1B  are, respectively, a part of a cross section view and an enlarged view of an end face polishing apparatus according to Embodiment 1 of this invention; 
       FIGS. 2A and 2B  are, respectively, a perspective view and a top view of a jig plate according to Embodiment 1 of this invention; 
       FIGS. 3A and 3B  are, respectively, a plan view and a cross section view of a jig plate according to Embodiment 1 of this invention; 
       FIGS. 4A and 4B  are, respectively, a perspective view and a cross section view of a jig plate and a polishing plate according to Embodiment 2 of this invention; and 
       FIGS. 5A and 5B  are, respectively, a plan view and a cross section view of a jig plate and a polishing plate according to Embodiment 3 of this invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The embodiments of the present invention are explained below referring to the figures. 
   Embodiment 1 
     FIGS. 1A and 1B , respectively, are a part of a perspective view and an enlarged view of an end face polishing apparatus of an embodiment of this invention. 
     FIGS. 2A and 2B , respectively, are a perspective view and a top view of a jig plate, and  FIGS. 3A and 3B , respectively, are a front view and a cross section view of a jig plate. 
   As shown in  FIG. 1 , the rotating shaft of the motor  11  for self-rotation is firmly fixed to the center portion of the first rotation transmitting shaft  12 , and on the first rotation transmitting shaft  12  a plurality of first coupling pins  13  are fixed on the concentric circle with the rotation center as the fulcrum. Then, the respective first coupling pins  13  are coupled rotatably to the eccentric portion of the corresponding respective rotation transmitting plates  14 . The eccentric portion of the respective rotation transmitting plates  14  are fixed with second coupling pins  15 . The respective second coupling pins  15  are coupled to a second rotation transmitting plate  16 . 
   On the other hand, the rotating shaft of the motor  17  for revolution is firmly fixed with a center potion of the driving gear  18 , and this driving gear  18  engages with a following gear  19 . This following gear  19  is firmly fixed to a periphery of the lower portion of the revolution transmitting shaft  20 , and around the periphery of the upper portion of this revolution transmitting shaft  20 , a bearing cylinder portion  22  of the apparatus body  21  is coupled. Then, this revolution transmitting shaft  20  is inserted with a rotating shaft  23  for self-rotation in a position that is eccentric by a predetermined amount from the rotation center, and the lower end portion of the rotating shaft  23  for self-rotation is fixed to the center portion of the second rotation transmitting plate  16 . 
   Further, the upper end portion of the rotating shaft  23  for self-rotation is connected to the polishing plate  25  with the coupling member  24 , and further the polishing member  25   a  is provided on the upper surface portion of the polishing plate  25 . 
   On the other hand, in the apparatus body  21 , a jig plate  30  fixed with a plurality of rod-shaped members W such as a ferrule are supported by a support mechanism  26 . 
   Next, the support mechanism  26  and the jig plate  30  will be explained in detail. 
   As shown in  FIGS. 2A ,  2 B and  FIGS. 3A ,  3 B, the jig plate  30  is rectangular in shape, and is provided with mounting pieces  32  opposite the plurality of recess portions  31  formed on a side surface opposite to each other in a pair. In between the mounting pieces  32  and the recess portions  31  the rod-shaped member W is inserted to fix the mounting pieces  32  with the fixing screw  33 , thereby detachably fixing the rod-shaped member W to the jig plate  30 . 
   Further, in the upper face center portion of the jig plate  30  is provided a boss portion  35 , at the center of which a through hole  36  is provided in the direction of the thickness of the boss portion  35 . The upper portion side of this through hole  36  is a taper portion  37  which increases toward the opening. 
   Further, the region opposite the polishing plate  25  at the lower surface of the jig plate  30  is provided with a slidable contact member  40  slidably contacting the polishing plate  25  with low friction. In this embodiment, the slidable contact member  40  comprises four ball members  41  mounted on the lower surface of the jig plate  30  for rotation relative to the jig plate  30 , holding holes or pockets  42 , and plate members  43 . Specifically, the holding holes or pockets  42  are formed on the lower surface of the jig plate  30 , and each of the ball members  41  which is spherical is inserted in a respective one of the holding holes  42 . Each of the holding holes  42  is covered with one of the plate members  43  having an opening of a diameter slightly smaller than a diameter of the ball members  41 , so that the ball members  41  are rotatably supported on the lower surface of the jig plate  30 . Since the ball members  41  relative to the jig plate  30  the polishing plate  25 , there is low friction between the jig plate and the polishing plate so that the jig and the polishing plate can be maintained in a horizontal state. Further, the jig plate  30  is mounted with rod-shaped members W which protrude from the slidable contact member  40 . 
   On the other hand, the support mechanism  26 , is structured by a pressing shaft  61  for pressing downwards with a predetermined pressure force to the fixed portion  21   a  fixed to the apparatus body  21 , and a rotation stopping pin  62  formed in parallel to the pressing shaft  61 . The tip end of the pressing shaft  61  is a conical portion  61   a , which is inserted to the taper portion  37  provided in the boss portion  35  of the jig plate  30  and thus presses the jig plate  30  downwards. Further, the rotation stopping pin  62  is engaged to the notch portion  38  formed in the boss portion  35  to regulate the movement of the rotation direction of the jig plate  30 . 
   Namely, the jig plate  30  is pressed in the direction of the polishing plate  25  by the pressing shaft  61 , in a state where the movement of the rotation direction is regulated by a rotation stopping pin  62 , is supported on a polishing plate  25  by a tip end portion of the rod-shaped member W fixed by a mounting piece  32 . Then, when the rod-shaped member W is polished for a predetermined amount, the slidable contact member  40  slidably contacts the polishing plate  25  and the jig plate  30  is supported in parallel to the polishing plate  25 , to thereby regulate the polishing amount of the rod-shaped member W. 
   In this way, by providing a slidable contact member  40  slidably contacting the polishing plate  25  with low friction in the lower surface of the jig plate  30 , the rod-shaped member W can be polished with the position of the polishing plate  25  slidably contacting the jig plate  30  as a standard for polishing, therefore the lengths of the rod-shaped member W can be made uniform as well as reducing the shift or variation in radius of curvature, polishing angle and eccentricity. Further, since there is no need to make uniform the lengths of the rod-shaped member w by removing in advance the adhesive attached to the rod-shaped member W or the like, the polishing process can be simplified. 
   Next, the above-described operation of the end face polishing apparatus of this embodiment is described. 
   As shown in  FIG. 1A , first, in a revolving movement, the revolution transmitting shaft  20  is rotated through the gears  18  and  19  by driving the motor  17  for revolution to rotate the polishing plate  25  in a revolving motion by a predetermined eccentric amount. In this case, the rotating shaft  23  for self-rotation is in the revolution transmitting shaft  20 . In between this and the first self-rotation transmitting plate  12  a plurality of rotation transmitting plates  14  are arranged, so that the rotation transmitting plates  14  rotate respectively in a same phase as the revolution transmitting shaft  20  in the direction of the first coupling pins  13 . Accordingly, even if the first self-rotation transmitting plate  12  stops, or is rotating, the rotation of the revolution transmitting shaft  20  will not be regulated. 
   On the other hand, in a self-rotating movement, the first self-rotation transmitting plate  12  is rotated by driving the motor  11  for self-rotation. Since the first coupling pin  13  is on the same concentric circle as the first self-rotation transmitting plate  12 , the same trail as described above is taken, the rotating shaft  23  for self-rotation is eccentric by a predetermined amount, but is coupled though the rotation transmitting plates  14  so that the same number of rotation as the first self-rotation transmitting plate  12  is transmitted to the rotating shaft  23  for self-rotation. 
   In this way, the polishing plate  25  self-rotates to revolve by the rotation movement of the revolution transmitting shaft  20  and the rotating shaft  23  for self-rotation. 
   On the other hand, the jig plate  30  is regulated in the movement of the rotation direction by the rotation stopping pin  62  in respect to the polishing member  25   a  of the polishing plate  25 , and the end face of the rod-shaped member W is pressed to the polishing member  25   a , in a state where the jig plate  30  is biased in the direction of the polishing plate  25  by the pressing shaft  61 . 
   At this time, with the variation in length of the respective rod-shaped members W, the jig plate  30  does not become parallel to the polishing plate  25 , and the end face of the rod-shaped member W is tilted and polished. However, as polishing carries on, the slidable contact member  40  provided on the lower surface of the jig plate  30  slidably contacts the polishing plate  25 , the jig plate  30  is supported parallel to polishing plate  25 , and the polishing plate  25  is polished as the standard for polishing. In this way, the lengths of the rod-shaped member W may be made uniform, as well as reducing the shift and variation of a radius of curvature, a polishing angle and eccentricity. Therefore, the tip end of the rod-shaped member W is processed to be an ideal convex spherical surface. 
   Embodiment 2 
   In the above Embodiment 1, the ball member  41  which is a slidable contact member  40  is held rotatably in the lower surface of the jig plate, but in Embodiment 2, an example of a ball member provided rotatably on the polishing surface is explained. 
     FIGS. 4A and 4B  are a perspective view and a cross section view of a jig plate and a polishing plate according to Embodiment 2. Further, members that have similar functions as those in the embodiment described above have the same reference numerals and explanation is omitted. 
   As shown in  FIGS. 4A and 4B , the slidable contact member  40  in this embodiment has an annular shape, and is structured by a holding portion  45  formed with a groove  46  in the circumferential direction of one end face, and a plurality of spherical shape ball members  41  rotatably held in the groove  46  of the holding portion  45 . The slidable contact member  40  is fixed in the region opposing the jig plate  30  in the peripheral portion of the polishing plate  25 . 
   With this structure, similar to the above described Embodiment 1, since the rod-shaped member W may be polished with the polishing plate  25  as the standard, the length of the rod-shaped member W can be made uniform as well as reducing the shift and variation of the radius of curvature, the polishing angle and the eccentricity. Further, since there is no need to make uniform the length of the rod-shaped member W by removing in advance the adhesive attached to the rod-shaped member W or the like, the polishing process may be simplified. 
   Embodiment 3 
   In the above described Embodiments 1 and 2, the slidable contact member  40  was a ball member  41  so that slidable contact was with low friction, but Embodiment 3 is an example where a metal material is used as a slidable contact member which slidable contacts with low friction. 
     FIGS. 5A and 5B  are a plan view and a cross section view of a jig plate and a polishing plate according to Embodiment 3. Further, members that have similar functions as those in the embodiment described above have the same reference numerals and explanation is omitted. 
   As shown in  FIG. 5 , the slidable contact member  40  of this embodiment is made of a protruding portion  50  which is a peripheral portion of the polishing plate  25  protruding elongated in the direction of the jig plate  30 . The polishing plate  25  provided with an elongated slidable contact member  40  is formed of oil-less metal with low friction resistance at time of slidable contact. 
   In this way, by making the slidable contact member  40  the protruding portion  50  which is the protruding peripheral portion, and forming at least the protruding portion  50  of the polishing plate  25  with oil-less metal, the structure can be simplified as well as preventing the chip made when the rod-shaped member W is polished effecting the slidable contact with low friction. 
   With this structure, similar to the above described Embodiments 1 and 2, since the rod-shaped member W may be polished with the polishing plate  25  as the standard for polishing, the length of the rod-shaped member W can be made uniform, as well as reducing the shift and variation of the radius of curvature, the polishing angle and the eccentricity. Further, since there is no need to make uniform the length of the rod-shaped member W by removing in advance the adhesive attached to the rod-shaped member W or the like, the polishing process may be simplified. 
   Other Embodiments 
   The embodiments of this invention have been described, but the fundamental structure of the end face polishing apparatus is not limited to that described above. 
   For example, the polishing plate  25  in the above described Embodiments 1 to 3 may be provided with an adjustment mechanism for adjusting only the height of the polishing member  25   a  without changing the height of the region that the slidable contact member  40  slidably contacts. By this, the length of the rod-shaped member W can be adjusted. 
   As described in detail in the embodiments, the end face polishing apparatus of this invention is provided with a slidable contact member on either one of the jig plate or the polishing plate to contact the other with a low friction, so that polishing with the polishing plate as the standard for polishing may be conducted, the length of the rod-shaped member W can be made uniform, as well as reducing the shift and variation of the radius of curvature, the polishing angle and the eccentricity. Further, since there is no need to make uniform the length of the rod-shaped member W by removing in advance the adhesive attached to the rod-shaped member W or the like, the polishing process may be simplified.