Abstract:
An end face polishing apparatus has a jig plate for supporting at least one workpiece having an end face and a polishing member for polishing the end face of the workpiece. A support mechanism supports the jig plate to undergo movement in a direction toward the polishing member to bring the end face of the workpiece into pressure contact with the polishing member solely under the weight of the jig plate.

Description:
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 this eccentric plate is 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 the end faces of the ferrules are polished. 
     SUMMARY OF THE INVENTION 
     As described above, the conventional optical fiber end face polishing apparatus conducts polishing by pressing with spring and the like the end faces of a plurality of ferrules held by the jig plate to the polishing member fixed to the self-rotating and revolving polishing plate. There is no problem if the number of ferrules mounted on the jig plate are always the same. However, if a jig plate which may normally hold a plurality of ferrules (6 to 12) instead holds a few number of ferrules (3 to 4), the variation in the load added to one ferrule becomes large, thereby increasing the variation of the size of the end face shape R. Further, in a case that the load is controlled by adjusting the force of the spring, it is required to decrease the adjustment error of the spring force by mechanical control which may be difficult to accomplish. 
     The object of the present invention, in view of the above, is to provide an end face polishing apparatus which may polish while adding a certain load on the ferrule when polishing the end face of the ferrule. 
     To solve the above object, according to a first aspect of the present invention, an end face polishing apparatus has 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. The jig plate is supported in a state where rotation is regulated, and is provided with at least the mounting portion of the rod-shaped member movable in the vertical direction and is supported to the jig plate by the tip end of the rod-shaped member. 
     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 jig plate is supported movably in the vertical direction by the support mechanism, and the mounting portion of the rod-shaped member is provided integrally with the peripheral portion of the jig plate. 
     According to a third aspect of the present invention, in the second aspect of the invention, an end face polishing apparatus is characterized in that the jig plate is formed with a through hole or a recessed groove in the center, whereas the support mechanism has a support shaft that may be inserted or fitted to the through hole or the recessed groove, and both are engaged movably in the vertical direction. 
     According to a fourth aspect of the present invention, in the third aspect of the invention, an end face polishing apparatus is characterized in that the through hole or the recessed groove and the support shaft are engaged to restrict the rotation of the jig plate with the support shaft as the center. 
     According to a fifth aspect of the present invention, in the third or fourth aspect of the invention, an end face polishing apparatus is characterized in that the engaging portion formed with the through holes and recessed grooves of the jig plate is exchangeable, in which by exchanging with a pressurizing engaging portion having a recess portion at the apex portion for receiving the tip end of the support shaft, the jig plate is pressurized by the support shaft downwards with a predetermined pressure. 
     According to a sixth aspect of the present invention, in the first aspect of the invention, an end face polishing apparatus is characterized in that the jig plate is supported by the support mechanism, and the mounting portion of the rod-shaped member is supported to the jig plate movably in the vertical direction. 
     In the end face polishing apparatus of the present invention, by the weight of the jig plate, a certain load may always be applied to the rod-shaped member. Further, since the load is applied by the weight of the jig plate, the structure of the apparatus can be simplified. Further, since polishing can be conducted by applying a certain load to the rod-shaped member, the accuracy of the shape of the polishing surface can be improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
     FIG. 1 is a part of across sectional view of an end face polishing apparatus according to Embodiment 1 of this invention; 
     FIG. 2 is a top view of an end face polishing apparatus according to Embodiment 1 of this invention; 
     FIG. 3 is a perspective view of a jig plate according to Embodiment 1 of this invention; 
     FIGS. 4A and 4B are, respectively, a front view and a cross sectional view of a jig plate according to Embodiment 1 of this invention; 
     FIG. 5 is a schematic perspective view of a jig plate and a polishing plate according to Embodiment 2 of this invention; and 
     FIG. 6 is a schematic perspective view of a jig plate and a polishing plate according to other embodiments of this invention. 
     FIG. 7 is a partial cross-sectional view of a jig plate according to another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments of the present invention are explained below referring to the figures. 
     Embodiment 1 
     FIG. 1 is a part of a cross sectional view of an end face polishing apparatus of an embodiment of this invention. FIG. 2 is a top view of an end face polishing apparatus, FIG. 3 is a perspective view of a jig plate, and FIGS. 4A and 4B are a top view and a cross section view of a jig plate, respectively. 
     As shown in FIGS. 1 and 2, the rotating shaft of a motor  11  for self-rotation is firmly fixed to the center portion of a first self-rotation transmitting plate  12 , and on the first self-rotation transmitting plate  12  a plurality of first coupling pins  13  are fixed on the concentric circle with the rotation center as a 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 self-rotation transmitting plate  16 . 
     On the other hand, the rotating shaft of a motor  17  for revolution is firmly fixed with a center potion of a driving gear  18 , and the driving gear  18  engages with a following gear  19 . The follower gear  19  is firmly fixed to a periphery of the lower portion of a revolution transmitting shaft  20 , and around the periphery of the upper portion of the revolution transmitting shaft  20  is fitted a bearing cylinder portion  22  of the apparatus body  21 . Then, the revolution transmitting shaft  20  is rotatably fitted 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 self-rotation transmitting plate  16 . 
     Further, the upper end portion of the rotating shaft  23  for self-rotation is connected to a polishing plate  25  with the coupling member  24 , and further a polishing member  25   a  is provided on the upper surface portion of the polishing plate  25 . 
     On the other hand, on the apparatus body is supported a jig plate  30  fixed with a plurality of workpieces or rod-shaped members W, such as ferrules, by a support mechanism  26 . 
     Next, the support mechanism  26  and the jig plate  30  will be explained in detail. 
     As shown in FIGS. 1 and 2, the support mechanism  26  comprises a support arm portion  27 , the cross section of which is rectangular in shape, extending horizontally from the apparatus body too the center of the polishing plate  25 , and a support shaft  28  provided towards the polishing plate from the tip end of the support arm portion  27 . 
     On the other hand, the jig plate  30  is hexagonal in a plan view, and is provided with mounting pieces  32  opposite a plurality of V grooves  31  formed in the peripheral portion. In between the mounting pieces  32  and the V grooves  31 , the rod-shaped member W is sandwiched to fix the mounting pieces  32  with the fixing screws  33 , thereby detachably fixing the rod-shaped member W to the jig plate  30 . 
     Further, as shown in FIGS. 3 and 4, in the upper surface center portion of the jig plate  30  is provided a boss portion  35 , at the center of which an insertion hole  36  penetrated in the direction of the thickness of the boss portion  35  is provided so the support shaft  28  is insertable. The boss portion  35  is fixed detachably to restrict the movement of the rotation direction. 
     The jig plate  30  is provided with through holes  34  in the thickness direction of the boss portion  35  through the insertion hole  36 . By inserting the support shaft into the through hole  34  and insertion hole  36  of the boss portion  35  of the jig plate, the jig plate  30  is held movably in the axial direction of the support shaft  28  in a state opposing the polishing member  25   a,  and is supported on the polishing plate  25  by the tip end portion of the rod-shaped member W fixed by the mounting pieces  32 . For reference, the insertion hole  36  is not always penetrated, and it may be formed in the shape of convex groove coupling to the tip end portion of the support shaft  28 . 
     Further, the movement in the rotation direction of the jig plate  30  is restricted. The structure that restricts the rotation direction is not particularly limited. For example, the support shaft  28  may be a shape where the cross section is rectangular, to restrict the movement of the rotation direction by having the through holes  34  of the jig plate  30  to be rectangular, or an engaging arm which engages to the periphery of the jig plate  30  may be extendedly provided from the support arm  27 . 
     In such a jig plate  30 , the tip end face of the rod-shaped member W fixed by mounting pieces  32  is press-contacted to the polishing member  25   a  by the own weight of the jig plate  30 . 
     In such a structure, since polishing can be carried out with a constant pressure by the weight of the jig plate  30  itself, regardless of the progress of the polishing of the rod-shaped member W, the R shape accuracy of the tip end face of the rod-shaped member W may be improved. Further, since the polishing amount is proportional to the polishing time, management of the accuracy and management of the polishing time may be easily conducted. Further, since the jig plate  30  is utilized to press using its own weight, there is no need to adjust pressure unlike when pressure added mechanically by a spring or the like. 
     Note that, even if a conventional mechanical pressing means such as a spring is provided in the end face polishing apparatus, by just replacing the boss portion  35 , it may become a pressure type end face polishing apparatus. 
     FIG. 7 shows another embodiment which differs from the embodiment shown in FIG. 4B in that the boss portion  35  comprises an engaging portion having a recessed groove  35   a.  The support shaft  28  has an end extending into the recessed groove  35   a.    
     Next, the operation of the end face polishing apparatus in the embodiment above will be explained. 
     As shown in FIGS. 1 and 2, 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 the same phase as the revolution transmitting shaft  20  around the first coupling pins  13 . Accordingly, even if the first self-rotation transmitting plate  12  is stopped, or is rotating, the rotation of the revolution transmitting shaft  20  will not be restricted. 
     On the other hand, as to the self-rotation motion, by driving the self-rotation motor  11 , the first self-rotation transmitting plate  12  is rotated. Since the first coupling pin  13  is on a concentric circle of the first self-rotation transmitting plate  12 , it traces the same locus mentioned above. Although the rotating shaft  23  for self-rotation is rotated by a predetermined eccentric amount, since it is coupled by the rotation transmitting plate  14 , a rotation of the same rotation number as that of the first self-rotation transmitting plate  12  is transmitted to the rotating shaft  23  for self-rotation. 
     In this way, the polishing plate  25  revolves while self-rotating by the rotation movement of the revolution transmitting shaft  20  and the rotating shaft  23  for self-rotation. On the other hand, since the jig plate  30  is held movable in the axial direction to the support shaft  28 , the respective rod-shaped members W is pressed at the end face to the polishing member  25   a  by the own weight of the jig plate  30 . 
     In this case, the rod-shaped member W is pressed to the polishing member  25   a  by the constant pressure regardless of the progress of polishing so that the end face of the rod-shaped member W is processed to be an ideal convex spherical surface. 
     Embodiment 2 
     FIG. 5 is a perspective view of a jig plate and a support mechanism according to Embodiment 2 of this invention. 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 jig plate  30 A of this embodiment is rectangular in shape, and on one of the opposing surfaces, are V grooves  31  for holding the rod-shaped members W and mounting pieces  32 . On both ends of the jig plate  30 A in the longitudinal direction are extendedly provided narrow width portions  37  with narrow widths. 
     In a support mechanism  26  which supports such a jig plate  30 A, is comprised of a pair of base stands  40  provided sandwiching the polishing plate  25 , and on the upper portion of this base block  40  is provided an engaging groove  41  to engage with the narrow width portion  37 . By engaging a narrow width portion  37  with this engaging groove  41 , the jig plate  30 A is held movably in a vertical and horizontal direction in a state where the rotation direction movement of the jig plate  30 A is restricted, and is supported on the polishing plate  25  through the tip end portion of the rod-shaped member W fixed by the mounting pieces  32 . 
     With such a structure, the jig plate  30 A can polish the rod-shaped member W always with a uniform load. Therefore, the polishing accuracy of the rod-shaped member W may be improved. 
     Other Embodiments 
     The embodiments of this invention have been described above, but the fundamental structure of the end face polishing apparatus is not limited to that described above. 
     For example, the jig plates  30  and  30 A are held movable in the vertical direction in the above described Embodiments 1 and 2, but it is not limited to this, and as a different structure of the holding mechanism for holding the rod-shaped member W of the jig plate, the jig plate may be held movable in the vertical direction with just the rotation direction movement of the holding mechanism restricted. 
     Such an example is shown in FIG.  6 . Further, FIG. 6 shows a perspective view of a jig plate and a support mechanism according to another embodiment of this invention. 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. 6, a jig plate  30 B of this embodiment is rectangular in shape, and on the side surfaces of the opposing surfaces are provided a pair of sliding portions  38  held movably in the vertical direction, and mounting pieces  32  are fixed to the sliding portions  38 . In more detail, by inserting the slide portions  38  into through holes  39  penetrated in the thickness direction, which are provided on the jig plate  30 B and shaped similar to the slide portions  38 , the slide portions  38  are held movable in the vertical direction in a state that the rotation direction movement of the slide portions  38  is restricted. Further, on one side of the slide portion  38  is formed V grooves  31  for sandwiching and holding the rod-shaped member W, and the rod-shaped member W may be fixed between the slide portion  38  and the mounting piece  32 . 
     Further, similar to the above Embodiment 2, the support mechanism  26  of this embodiment is a pair of base stands  40 , and by engaging the narrow width portions  37  provided on both ends in the longitudinal direction of the jig plate with the engaging grooves  41  provided on the base stand  40 , the movement in the rotation direction of the jig plate  30 B may be restricted. 
     With such a structure, the rod-shaped member W is held movable in the vertical direction by the holding mechanism comprised of the fixed slide portions  38  and the mounting pieces  32 , and is held on the polishing plate  25  by the tip face of the rod-shaped member W, so that the own weight of the slide portions  38  and the mounting pieces  32  are on the rod-shaped member W. By polishing in this state, polishing can be carried out similarly to the above Embodiments 1 and 2. Further, with this structure, since the slide portions and the mounting pieces for fixing each of the rod-shaped members W are provided independently, even in a case where there is only one rod-shaped member W, polishing may be carried out without deteriorating the polishing accuracy. 
     The jig plate  30 B may be fixed to the support mechanism  26 , and further, may be a structure similar to Embodiment 1, such that it is fixed to the support shaft  28 . 
     As described in detail in the embodiments, in the end face polishing apparatus of this invention, the jig plate is supported movably in the vertical direction in a state that the movement of the rotation direction is restricted, therefore the polishing of the rod-shaped member fixed to the jig plate is carried out by the own weight of the jig plate. Accordingly, the rod-shaped member may be polished always with a constant load without interfering with the progress of the polishing of the rod-shaped member by conducting mechanical adjustments, thereby improving the polishing accuracy of the end face of the rod-shaped member. Further, since the polishing amount is proportional to the polishing time, the polishing accuracy and the polishing time may be easily managed.