Abstract:
An optical fiber cutting device including: a rotatable blade including positioning holes; a first fastening member that is engageable with said positioning holes; and a second fastening member that is engageable with said positioning holes. When said first fastening member is engaged with a first one of said positioning holes, said second fastening member is not engaged with any of said positioning holes. Thus, the blade is fixed in a non-rotating state after being rotated by a predetermined angle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority under 35 U.S.C. §119(a) from Japanese Patent Application No. 2005-063953, filed on Mar. 8, 2005, in the Japanese Patent Office, the disclosure of which is incorporated herein in its entirety by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     Devices, systems, and methods consistent with the invention relate to optical fiber cutting.  
         [0004]     2. Description of the Related Art  
         [0005]     In the related art, an optical fiber cutting device has been proposed wherein a disk-like blade having a cutting edge at a circumference thereof is rotatably mounted so as to utilize an unused portion of the cutting edge by rotating over a used portion of the cutting edge, when the used portion of the cutting edge has been worn down. This results in a longer lifetime of the cutting edge. In this device, the optical fibers are cut off while keeping the cutting edge fixed in a non-rotating state.  
         [0006]      FIG. 1  is a front view showing an example of an optical fiber cutting device of related art,  FIG. 2A  is a plan view and  FIG. 2B  is a side view thereof.  
         [0007]     A cutting procedure using an optical fiber cutting device  110  is performed such that an optical fiber  101  is held at a top portion and bottom portion thereof by two clamps  121  ( 121   a ,  121   b ),  122  ( 122   a ,  122   b ), the cutting edge of the blade  150  is moved toward an intermediate portion of the optical fiber between the held positions in a direction perpendicular to the longitudinal direction of the optical fiber to make a cut in a surface of the optical fiber  101 , and a pillow (a pressing member)  123  is pressed against the optical fiber  102  from the rear side opposite to the cut.  
         [0008]     It is important for obtaining a good section that the cut made in the optical fiber  101  has a proper size and depth. Therefore, the relative height of the cutting edge to the optical fiber  101  requires proper adjustment. The blade  150  is supported free to rotate on a blade holder  135  with a rotary shaft  137 .  
         [0009]     The height of the edge moves up and down through swinging of the blade holder  135  on the axis of a support shaft  134  parallel to the axial direction of the rotary shaft  137 . By rotating an adjustment screw  136 , the blade  150  moves up and down on the axis of the support shaft  134 .  
         [0010]     After repeatedly cutting optical fibers  101 , a portion of the cutting edge is worn down gradually, resulting in poor cutting. Then, good cutting can be again performed using an unused portion of the cutting edge by rotating the blade  150  on the axis of the rotary shaft  137  only by an angle corresponding to the rotary pitch between two adjacent holes of the positioning holes.  
         [0011]     In order to set each of rotated positions of the cutting edge, there are several positioning holes  151  in the blade  150  along the circumference thereof, and the rotated position of the cutting edge is set using a setscrew  141  in one of these holes. Thus, when the cutting edge is rotated to come full circle, there remain no unused portions of the cutting edge and the blade  150  should be replaced with a new one.  
         [0012]     There is also a type of optical fiber cutting device where the blade  150  has no positioning holes and may be set by just holding both sides of the edge. Namely, there are only indicative divisions or numbers  154  printed on the side of the blade  150 , and when a portion of the cutting edge is worn down, the edge is rotated by one division and the both sides of the blade  150  is held using a setscrew  141  to set the rotated position of the cutting edge, and thus an unused portion of the cutting edge will be utilized.  
       SUMMARY OF THE INVENTION  
       [0013]     However, there have been the following problems in the related art optical fiber cutting device  110  discussed above.  
         [0014]     As shown in  FIG. 3 , whenever a portion of the cutting edge is worn down, another portion thereof is positioned according to the rotational movement of the cutting edge from one hole to the next of the positioning holes. Thus, unused portions  153  undesirably remain between the used portions  152 .  
         [0015]     In order to use up all of the portions of the cutting edge, as shown in  FIG. 4 , the number of the positioning holes  151  could be increased. However, if the number of the positioning holes  151  is increased, the intervals between the holes become narrower, the strength decreases, and manufacturing thereof comes more difficult, resulting in the higher production cost of the blade  150 .  
         [0016]     Further, as shown in  FIG. 5 , when the positioning holes  151  are formed farther from the center of blade  150 , the number of the positioning hole  151  can be increased keeping the intervals between the holes at a reasonable level. In this case, however, as the number of the holes increases, the production cost becomes higher. Additionally, since the positioning holes  151  are near the cutting edge, internal defects are liable to occur resulting in nicks of the cutting edge especially in such a case where the blade  150  may be made by molding or sintering.  
         [0017]     On the other hand, in such an optical fiber cutting device that a blade  150  has no positioning holes  151  and the edge is directly clamped on its side, the blade  150  may be used by intermittent rotation at a short segment so as to use full portions of the cutting edge because an angle of rotation of the blade  150  is not limited by the rotary pitch of the positioning holes  151 . However, since accurate positioning cannot be achieved, there are such disadvantages that a part (near a boundary between the used and the unused portions) of the used portion  152  already worn down is undesirably reused and that the portion to be used next  152  is set up after skipping a large unused portion  153 .  
         [0018]     The invention has been made in view of the above problems. According to the invention, an optical fiber cutting device is provided where the number of positioning sites of the cutting edge can be greatly increased with respect to the number of positioning holes formed in the blade, and where the cutting edge can be accurately positioned at all the positioning sites.  
         [0019]     According to an aspect of the invention, an optical fiber cutting device is provided, including: a rotatable blade including positioning holes; a first fastening member that is engageable with said positioning holes; and a second fastening member that is engageable with said positioning holes. When said first fastening member is engaged with a first one of said positioning holes, said second fastening member is not engaged with any of said positioning holes, where the blade is fixed in a non-rotating state after being rotated by a predetermined angle.  
         [0020]     According to another aspect of the invention, an optical fiber cutting device is provided, including: a rotatable blade, comprising engagement elements disposed along a circumference thereof at a first pitch; a first fastening member that is engageable with said engaging elements; and a second fastening member that is engageable with said engagement elements, where said first fastening member and said second fastening member are separated in a direction along said circumference of said rotatable blade at a second pitch different from the first pitch.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The above and/or other aspects of the invention will be more apparent by describing in detail exemplary embodiments of the invention with reference to the accompanying drawings, in which:  
         [0022]      FIG. 1  is a front view showing an example of a related art optical fiber cutting device;  
         [0023]      FIG. 2A  is a plan view of the optical fiber cutting device shown in  FIG. 1 , and  FIG. 2B  is a side view thereof;  
         [0024]      FIG. 3  is a front view showing an example of a related art blade;  
         [0025]      FIG. 4  is a front view showing another example of a related art blade;  
         [0026]      FIG. 5  is a front view showing still another example of a related art blade;  
         [0027]      FIG. 6  is a front view showing an exemplary embodiment of an optical fiber cutting device according to the invention;  
         [0028]      FIG. 7A  is a plan view of the optical fiber cutting device shown in  FIG. 6 , and  FIG. 7B  is a side view thereof;  
         [0029]      FIGS. 8A and 8B  are a plan view and a side view, respectively, showing a state where the used portion of the cutting edge has been switched around to an unused portion;  
         [0030]      FIG. 9  is a front view of a cutting edge used for the optical fiber cutting device shown in  FIG. 6 ;  
         [0031]      FIG. 10A  is a front view showing another exemplary embodiment of an optical fiber cutting device according to the invention, and  FIG. 10B  is a side view thereof; and  
         [0032]      FIGS. 11A and 11B  are a plan view and a side view, respectively, showing a state where the used portion of the cutting edge has been switched around to an unused portion. 
     
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0033]     Exemplary embodiments of the invention will now be described below by reference to the attached Figures. The described exemplary embodiments are intended to assist the understanding of the invention, and are not intended to limit the scope of the invention in any way. Like reference numerals refer to like elements throughout.  
         [0034]      FIG. 6  is a front view showing an exemplary embodiment of an optical fiber cutting device according to the invention, and  FIG. 7A  is a plan view and  FIG. 7B  is a side view thereof.  
         [0035]     The optical fiber cutting device  10  holds horizontally an optical fiber  1  with a pair of upper and lower clamps  21  ( 21   a ,  21   b ),  22  ( 22   a ,  22   b ) disposed on the left side and the right side of a base  20 . A blade  50  is disposed between the clamps  21 ,  22 , and is moved substantially perpendicularly to the principal axis of the optical fiber  1  to make a cut in a surface of the optical fiber  1  by a cutting edge  70 . The optical fiber is cut off by applying stress to the cut through a push member  23  being pressed against the optical fiber  1  from the rear side opposite to the cut.  
         [0036]     It is important for obtaining a good section in the optical fiber  1  that the cut made in the optical fiber  1  has a proper size. Therefore, the device is configured so as to adjust properly the height of the blade  50  relative to the optical fiber  1 .  
         [0037]     Namely, in the optical fiber cutting device  10 , a sliding-guide shaft  32  is inserted through a slide bearing  31  disposed in the base  20  and a sliding block  33  moves linearly substantially in the horizontal direction.  
         [0038]     A blade holder  35  is attached via a support shaft  34  to the sliding block  33  pivotably around the horizontal support shaft  34  perpendicular to the sliding-guide shaft  32 , and by rotating an adjustment screw  36 , the blade holder  35  can pivot like a cantilever up and down on the axis of the support shaft  34 .  
         [0039]     The blade  50  is attached to the blade holder  35  rotatably around a rotary shaft  37  parallel to the support shaft  34 . Therefore, the height of the cutting edge  70  relative to the optical fiber  1  can be adjusted up and down by rotating an adjustment screw  36 .  
         [0040]     After repeatedly cutting the optical fibers  1 , a used portion of the cutting edge of the blade  50  is worn down gradually resulting in poor cutting. Then, good cutting can be again achieved using an unused portion of the cutting edge through rotating the blade  50  by a predetermined angle around the rotary shaft  37 .  
         [0041]     In order to position the blade at the given position and to fasten it up to the blade holder, a plurality of positioning holes  51  as an engagement element are formed in the side  50   a  of the blade  50  at substantially even intervals along a circumference with an appropriate radius.  
         [0042]     In the optical fiber cutting device  10 , two fastening members  41 ,  42  are provided for engaging with any particular ones of the positioning holes  51  arranged along the circumference in order to fasten up the cutting edge  70  in a non-rotating state to the blade holder. The two fastening members are positioned so that they should alternatively engage with the positioning holes as the blade is rotated. Namely, when the first fastening member  41  ( 42 ) is engaged with one of the positioning holes  51 , the second fastening member  42  ( 41 ) is engaged with none of the positioning holes. As the blade  50  is then rotated clockwise or counterclockwise, the second fastening member will be engaged with the other one of the positioning holes, but the first fastening member will be engaged with none of the positioning holes. A positioning mechanism shown in  FIGS. 7A, 7B  has an odd number of the positioning holes  51 , and the fastening member  41 ,  42  are disposed at the locations opposite to each other in respect of the rotary shaft  37 . Namely, in the positioning mechanism, the positioning holes  51  as an engagement element are arranged at substantially even intervals along the circumference around the rotary shaft  37  in the side  50   a  of the blade  50  and the two fastening members engaging with any ones of the positioning holes  51  have different rotary pitches in such a way that they cannot engage simultaneously with two of the positioning holes. As a result, the two fastening members can be alternately engaged with one of the positioning holes when the cutting edge  70  is rotated clockwise or counterclockwise. In a case where the number of the positioning holes is an even number, the two fastening members are disposed offset from the mutually right opposite location.  
         [0043]     The fastening members  41 ,  42  are, for example, setscrews, and are engaged with the positioning holes  51  or released from the positioning holes  51  through operations of being tightened or loosened.  
         [0044]     As shown in  FIGS. 7A and 7B , while the fastening member  41  is engaged with the positioning hole  51   a  of the blade  50 , the fastening member  42  is disposed so as to be located substantially at the center between the two positioning holes  51   c ,  51   d  adjacent to each other.  
         [0045]     As shown in  FIGS. 8A and 8B , while the fastening member  42  is engaged with the positioning hole  51   d  of the blade  50 , the fastening member  41  is disposed so as to be located at the middle point (center) between the two positioning holes  51   a ,  51   b  adjacent to each other.  
         [0046]     In other words, the number of the positioning holes  51  disposed in the blade  50  is half of the number of the positioning sites of the blade  50 , which are able to be positioned using the positioning holes  51  and the two fastening member  41 ,  42 . In a backward expression, the number of the positioning sites of the blade  50 , which are able to be positioned using the positioning holes  51  and the two fastening member  41 ,  42 , is twice as many as the number of the positioning holes  51  disposed in the blade  50 .  
         [0047]     In the blade  50  shown in  FIGS. 7A and 7B , and  FIGS. 8A and 8B , the number of positioning holes  51  is eleven and the positioning can be done at twenty-two sites. In other words, the positioning can be done at twice as many sites as the number of the positioning holes  51 , and it is only necessary to form half the number of the positioning holes  51  in the blade  50  with respect to the number of positioning sites. Since the second fastening member is disposed at the middle point (center) between two positioning holes  51  adjacent to each other while the first fastening member is engaged with one of the positioning holes of the blade, the cutting edge  70  can be positioned by rotating the blade  50  at even intervals.  
         [0048]     Additionally, it is possible to configure such a construction further using a third fastening member that while a first fastening member is engaged with one of the positioning holes, a second positioning holes and the third fastening member are arranged at two locations, respectively, which divide the rotary pitch of the positioning holes into three equal parts. In the case, since the first fastening member, the second fastening member, and the third fastening member, in this order for example, can be engaged one after the other with any of the positioning holes to be positioned during clockwise or counterclockwise rotation of the cutting edge, the rotary pitch of the rotation of the cutting edge comes to be substantially ⅓ of the pitch of the positioning holes.  
         [0049]     The following will describe the method of rotating the blade  50  by the predetermined angle when a portion of the cutting edge of the blade  50  is worn down.  
         [0050]     At the start, as shown in  FIGS. 7A and 7B , one ( 51   a ) of the positioning holes  51  of the blade  50  is beforehand fastened up with a setscrew  41  as a fastening member. Setscrew  42  is at a portion where no positioning holes  51  exist (at the center between  51   c  and  51   d ), it is optional if the setscrew is fastened up or not.  
         [0051]     In short, the blade  50  is positioned with one ( 51   a ) of the positioning holes  51  and the setscrew  41 , and a first portion of the cutting edge is to be used.  
         [0052]     Once the first portion of the cutting edge of the blade  50  is worn down, in order to use a second portion of the cutting edge, as shown in  FIGS. 8A and 8B , the setscrew  41  is loosened, and the blade  50  is rotated by half of the rotary pitch of the holes in the direction of the arrow to fasten up one ( 51   d ) of the positioning holes  51  with the setscrew  42 .  
         [0053]     Since the location of the setscrew  41  is then just at the portion where no positioning holes  51  exist (at the center between  51   a  and  51   b ), it is optional if the setscrew is fastened up or not. In short, the blade  50  is positioned with one ( 51   d ) of the positioning holes  51  and the setscrew  42 , and the second portion of the cutting edge is to be used.  
         [0054]     And so forth, by fastening the positioning holes  51  using the setscrews  41 ,  42  alternately, the blade  50  is rotated by the angle corresponding to ½ of the pitch between the positioning holes  51 ,  51  adjacent to each other and then good cutting can be performed using an unused portion of the cutting edge every time.  
         [0055]      FIG. 9  shows the blade  50  used in the above exemplary embodiment. The blade  50  has eleven positioning holes  51  and twenty-two positioning sites (i.e., twice as much as the number of the holes).  
         [0056]     As mentioned above, since the number of positioning sites of the blade  50  can be increased without increasing the number of positioning holes  51 , the used portions  52  of the cutting edge are continuous with no waste areas therebetween (i.e., there remains no intervening unused portions between the used portion  52  and the used portion  52 ). Further, since the number of the positioning holes  51  is half of that of the positioning sites, the production cost of blade  50  can be spared.  
         [0057]     Moreover, as the positioning can be always ensured with either of two fastening members (setscrews)  41 ,  42 , the rotated position of the cutting edge is accurately determined.  
         [0058]     Consequently, since the optical fiber cutting device  10  according to the invention can increase the number of positioning sites of a blade  50  relative to the number of positioning holes  51 , the lifetime of the edge is lengthened. As the number of the positioning holes  51  can be decreased with respect to the positioning sites of the blade  50 , the production cost of the cutting edges  50  can be reduced. Further, since the outer diameter of the blade  50  can be made smaller without reduction in the number of the positioning sites of the blade  50 , the device can also be made smaller. Additionally, the blade  50  can be accurately positioned even when the number of the positioning sites thereof may be increased.  
         [0059]      FIG. 10A  is a front view showing another exemplary embodiment of an optical fiber cutting device according to the invention, and  FIG. 10B  is a side view thereof.  
         [0060]     The optical fiber cutting device  11  employs a different type of fastening members  61 ,  62  in place of the fastening members  41 ,  42  such as, for example, a setscrew. The other components are similar to those in the optical fiber cutting device  10  as shown in  FIGS. 6-8 , and therefore repeated description will be omitted giving the like numerals to the corresponding components.  
         [0061]     The fastening members  61 ,  62  are composed of plungers having pressing members  61   b ,  62   b  (e.g., a spring) which press engagement portions  61   a ,  62   a  (e.g., a ball) at the tip against positioning holes  51  of a blade  50 .  
         [0062]     Thus, the optical fiber cutting device  11  does not need any operation to tighten or loosen the fastening members  61 ,  62  (which are used for the fastening members  41 ,  42  shown in  FIG. 7A ), and the blade  50  can be easily positioned only through rotating it by the necessary angle.  
         [0063]     The following will described the method of rotating the blade  50  by a predetermined angle when a portion of the cutting edge of the blade  50  is worn down.  
         [0064]     At the beginning, as shown in  FIGS. 10A, 10B , one ( 51   a ) of the positioning holes  51  of the blade  50  is beforehand fastened up with a fastening member (plunger)  61 . As the location of a fastening member (plunger)  62  is just at the portion where no positioning holes exist (at the center between  51   c  and  51   d ), the tip of the fastening member (plunger)  62  gets dented.  
         [0065]     In short, the blade  50  is positioned with one ( 51   a ) of the positioning holes  51  and the fastening member (plunger)  61 , and a first portion of the cutting edge is to be used.  
         [0066]     Next, once the first portion of the cutting edge of the blade  50  is worn down, in order to use a second portion of the cutting edge, as shown in  FIGS. 1A, 1B , the blade  50  is rotated by half of the rotary pitch of the holes in the direction of the arrow and thus the fastening member (plunger)  61  is released from one ( 51   a ) of the positioning holes  51  and one ( 51   d ) of the positioning holes  51  is fastened automatically with the fastening member (plunger)  62 .  
         [0067]     Since the location of the fastening member  61  is then just at the portion where no positioning holes  51  exist (at the center between  51   a  and  51   b ), the tip of the fastening member (plunger)  61  gets dented. In short, the blade  50  is positioned with one ( 51   d ) of the positioning holes  51  and the fastening member (plunger)  62 , and the second portion of the cutting edge is to be used.  
         [0068]     And so forth, when an unused portion of the cutting edge is required to use, only through rotating the blade  50  by the angle corresponding to ½ of the rotary pitch between the positioning holes  51 ,  51  adjacent to each other, the alternate fastening member (plunger)  61  or  62  is engaged automatically with one of the positioning holes  51  leading to automatic positioning of the blade  50 . And then good cutting can be performed using every time an unused portion of the cutting edge.  
         [0069]     In the above exemplary embodiment, since the number of the positioning sites can be increased twice as much as the number of the holes  51  formed in the blade  50 , there remains, as shown in  FIG. 9 , no intervening unused portions between the used portions  52 . Since the number of the positioning holes  51  will do only by half of that of the positioning sites, the production cost of cutting edges  50  can be spared. Moreover, as the positioning can be always ensured with either of two fastening members (plungers)  61 ,  62 , the rotated position of the cutting edge is accurately determined.  
         [0070]     Consequently, since the optical fiber cutting device  11  according to the invention can increase the number of positioning sites of a blade  50  than that of positioning holes  51 , the lifetime of the edge is elongated. As the number of the positioning holes  51  can be decreased than that of the positioning sites of the blade  50 , the production cost of the cutting edges  50  can be reduced. Since the outer diameter of the blade  50  can be made smaller without reduction in the number of the positioning sites of the blade  50 , the device can also be made compact. The blade  50  can be accurately positioned even when the number of the positioning sites thereof may be increased.  
         [0071]     Further, through fastening the blade  50  with fastening members (plunger)  61 ,  62 , it can be easily positioned only by simple rotation thereof.  
         [0072]     As discussed above, the exemplary embodiments provide a blade where the number of positioning sites of a cutting edge is greater than a number of positioning holes, so that the cutting edge can be accurately positioned at each of the positioning sites.  
         [0073]     While the invention has been particularly shown and described with reference to exemplary embodiments thereof, the invention is not limited to these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims.