Apparatus for cutting an optical fiber

Abstract: An optical fiber cutting apparatus is provided which comprises a plurality of clamps (10, 20, 62) for clamping an optical fiber (40). A scoring blade (52) is provided between two adjacent clamps (10, 62) for making a score on the optical fiber by moving within a plane substantially perpendicular to the optical fiber. A pushing member (54) is also provided for pushing the optical fiber from an opposite side of the score to cut the optical fiber. The pushing member is retracted after the optical fiber cut by the pushing member is rendered movable by releasing the two adjacent clamps while the optical fiber is still being bent by the pushing member.

Description: The present invention relates to an apparatus for cutting an optical fiber according to the preamble of claim 1, which is based upon EP-A-0 129 135. In order to properly join a pair of optical fibers, it is necessary that the surface of the connecting end of each fiber be flat and perpendicular to the fiber's axis. To provide such an end face, the distal end of each optical fiber needs to be properly cut prior to splicing the fibers. Conventionally, this fiber cutting has been done using a fiber cutting apparatus as shown in Figs. 1A to 1C. Fig. 1A illustrates an example of a conventional optical fiber cutting apparatus applicable to singlecore fibers. Reference numeral 10 denotes a first clamp, which comprises a clamp table 12 and a pincher 14. Pincher 14 is freely openable and closable to clamp table 12, and, when closed, it clamps a sheathed portion 42 of an optical fiber 40. Reference numeral 16 denotes a rubber member used to absorb the stress applied on sheathed portion 42 by pincher 14. In Figs. 1A-1C, pincher 14 is illustrated to move vertically with respect to clamp table 12. Actually, however, pincher 14 is often attached to clamp table 12 by means of a hinge 18 so as to be rockable to the clamp table, as shown in Fig. 2. The former design of first clamp 10 (see Figs. 1A-1C) is the same as the latter design (Fig. 2) in principle and is easier to see its operation. In this respect, therefore, a second clamp 20 is also illustrated in the same manner so that its pincher 24 is shown to move vertically with respect to a clamp table 22. Second clamp 20 comprises clamp table 22 and pincher 24. Pincher 24 is freely openable and closable to clamp table 22, and, when closed, it clamps an unsheathed or bare portion 44 (i.e., glass portion) of an optical fiber 40. Reference numeral 26 denotes a rubber member used to absorb the stress applied on glass portion 44 by pincher 24. Reference numeral 50 is a base for supporting clamp tables 12 and 22. Reference numeral 52 is a scoring blade provided between first clamp 10 and second clamp 20, which moves within a plane perpendicular to the axis of optical fiber 40 in the horizontal or arched direction and scores the optical fiber at the desired portion. Reference numeral 54 is a pushing member which applies bending stress on the scored optical fiber 40 from the opposite side of the score to cut the fiber. To clamp optical fiber 40, first, optical fiber 40 is placed on clamp tables 12 and 22, as shown in Fig. 1A, then first clamp 10 is closed (Fig. 1B), and finally, second clamp 20 is closed (Fig. 1C). Thereafter, scoring blade 52 is moved within a plane perpendicular to the axis of optical fiber 40 in the horizontal direction or the arched direction, to score the optical fiber at the desired portion. Then, pushing member 54 applies bending stress on the scored optical fiber 40 from the opposite side of the score to cut the fiber. As the pinchers of the individual clamps are sequentially closed, thus increasing the number of the clamping procedures, (1) the overall clamping operation is troublesome. And this operation would become more troublesome as the number of the clamps in use increases. (2) If wrong procedures are taken to close the clamps, it may twist or deform optical fiber 40. The conventional cutting apparatus further has the following shortcoming. Fig. 3 illustrates the cutting apparatus, applied to a single core fiber, in a different aspect. In Fig. 3, the same reference numerals as are used in Figs. 1A-1C are also used to specify the corresponding sections, thus omitting their otherwise redundant explanation. Reference numeral 62 is a third clamp. Scoring blade 52 is provided between second clamp 20 and third clamp 62 and is movable in the horizontal direction or in the arched direction, to score bare fiber 44 at the desired portion. To prepare an end face perpendicular to the axis of optical fiber 40, the score on the optical fiber should also be perpendicular to the fiber axis 88. To achieve this, optical fiber 40 needs to be clamped perpendicular to the moving direction 90 of scoring blade 52. However, sheathed portion 42 of optical fiber 40 is normally rolled and naturally curvy, so that the optical fiber even clamped may not be held straight as shown in Fig. 3. Therefore, the moving direction of scoring blade 52 is not perpendicular to the axis 88 of optical fiber 40 and the score would not be perpendicular to the fiber axis accordingly. The conventional cutting apparatus further has the following shortcoming. Fig. 4 illustrates the cutting apparatus, applied to a single core fiber, in another aspect. In Figs. 4, 5A and 5B, the same reference numerals as are used in the previously-described diagrams are also used to specify the corresponding sections, thus omitting their otherwise redundant explanation. Third clamp 62 comprises a clamp table 64 and pincher 66. Pincher 66 is freely openable and closable to clamp table 64, and, when closed, it clamps bare portion (i.e., glass portion) 44 of an optical fiber 40. Reference numeral 36 is a rubber member used to absorb the stress applied on glass portion 44 by pincher 66. Scoring blade 52 is moved in the horizontal direction or in the arched direction, to score bare fiber 44 at the desired portion, and then pushing member 54 is pressed against bare fiber 44, the fiber is cut (Fig. 5A). Pushing member 54 is then retracted (Fig. 5B), releasing the stress on the cut portions of bare fiber 44, so that the cut end of the fiber 44 and the end of a waste bare fiber 44A are likely to hit against each other. This may chip off or make a crack on the end face of bare fiber 44. The conventional cutting apparatus further has the following shortcoming. Figs. 6 and 7 illustrate the cutting apparatus, applied to a single core fiber, in a still different aspect. In Figs. 6 and 7, the same reference numerals as are used in the previously described diagrams are also used to specify the corresponding sections, thus omitting their otherwise redundant explanation. Reference numeral 92 is a base of the overall cutting apparatus, and numeral 94 is a set table. In the case where the diameter of the sheathed portion of the optical fiber is relatively large, and the optical fiber has a single core and needs a constant cutting length L, as shown in Figs. 6 and 7, sheathed portion 42 is stopped at the boundary between groove 82 and slit 84 of guide 80 so that the cutting length L becomes constant. On the other hand, if the diameter of the sheathed portion is relatively small (about 0.2S mm) and the cutting length L varies (see Fig. 8), sheathed portion 42 does not have a tendency to be curvy so that groove 82 is sufficient and it is unnecessary to form slit 84 in second guide 80. Sheathed portion 42 can freely be moved within grooves 76 and 82. Reference numeral 96 is a scale on which the end face of the fiber to be cut is aligned so as to determine the cutting length L. When this cutting apparatus is applied to cutting a multicore fiber, a stationary jig is mounted to optical fiber 40. As should be apparent from the above explanation given with reference to Figs. 6-9, different types of cutting apparatus should be conventionally provided depending on the types and uses of optical fibers to be cut and variation in the cutting length. An object of the present invention is to provide an optical fiber cutting apparatus, in which the cut ends of the fiber are prevented from being hit after the cutting of the fiber. A still further object of the present invention is to provide an optical fiber cutting apparatus which can be applied to different types of the optical fibers. According to the present invention, there is provided an optical fiber cutting apparatus as defined in claim 1. Embodiments of the invention are defined in claims 2 to 5. This invention can be more fully understood from the following detailed description of embodiments when taken in conjunction with the accompanying drawings, in which: Figs. 1A to 1C respectively show schematic side views of a conventional optical fiber cutting apparatus; Fig. 2 shows a schematic side view of a clamp in the conventional cutting apparatus of Figs. 1A to 1C; Fig. 3 shows a schematic plan view of the conventional cutting apparatus to which a curvy optical fiber is applied; Fig. 4 shows a schematic plan view of the conventional cutting apparatus in which the cutting blade scores a fiber; Figs. 5A and 5B respectively show schematic plan views of the conventional cutting apparatus in which the fiber is pushed by the pushing member; Fig. 6 shows a plan view of the conventional cutting apparatus, somewhat in detail; Fig. 7 shows a schematic cross sectional view of the conventional cutting apparatus of Fig. 6, taken along the axis thereof; Figs. 8 and 9 respectively show schematic plan views of other conventional cutting apparatus; Figs. 10A and 10B are schematic side views of an optical fiber cutting apparatus according to an embodiment of this invention; Figs. 11A to 11C are schematic side views of an optical fiber cutting apparatus according to another embodiment of this invention; Figs. 12A to 12D are schematic diagrams illustrating the states of the clamps and the fiber in the individual steps of an optical fiber cutting method according to another embodiment of this invention; Fig. 13 is a schematic plan view of a cutting apparatus for executing the cutting method comprising the steps as shown in Figs. 12A to 12D; Figs. 14A and 14B are cross sectional views of the cutting apparatus shown in Fig. 13 with its plate closed, as taken along lines A-A and B-B of Fig. 13, respectively; Figs. 15A and 15B are cross sectional views of the cutting apparatus shown in Fig. 13 with its plate slightly opened, as taken along lines A-A and B-B of Fig. 13, respectively; Embodiments of this invention will be explained below with reference to the accompanying drawings. In the following description, the same reference numerals are used to specify corresponding portions of the conventional cutting apparatus and the cutting apparatus according to the embodiments for the ease of understanding. Figs. 10A and 10B schematically illustrate an optical fiber cutting apparatus. Reference numeral 10 denotes a first clamp, which comprises a clamp table 12 and a pincher 14. Pincher 14 is freely openable and closable to clamp table 12, and, when closed, it clamps a sheathed portion 42 of an optical fiber 40. Reference numeral 16 denotes a rubber member used to absorb the stress applied on sheathed portion 42 by pincher 14. In Figs. 10A and 10B, pincher 14 is illustrated to move vertically with respect to clamp table 12. Actually, however, pincher 14 is attached to clamp table 12 by means of a hinge (not shown) so as to be rockable to the clamp table. The former design of first clamp 10 (see Figs. 10A and 10B) is the same as the latter design in principle and is easier to see its operation. In this respect, therefore, a second clamp 24 is also illustrated in the same manner so that its pincher 24 is shown to move vertically with respect to a clamp table 22. Second clamp 20 comprises clamp table 22 and pincher 24. Pincher 24 is freely openable and closable to clamp table 22, and, when closed, it clamps an unsheathed or bare portion 44 (i.e., glass portion) of an optical fiber 40. Reference numeral 26 denotes a rubber member used to absorb the stress applied on glass portion 44 by pincher 24. Reference numeral 50 is a base for supporting clamp tables 12 and 22. Reference numeral 52 is a scoring blade provided between first clamp 10 and second clamp 20, which moves within a plane perpendicular to the axis of optical fiber 40 in the horizontal direction or the arched direction and scores the optical fiber at the desired portion. Reference numeral 54 is a pushing member which applies bending stress on the scored optical fiber 40 from the opposite side of the score to cut the fiber. Pincher 14 of clamp 10 is attached to a plate 212 by means of a spring 15, while pincher 24 of clamp 20 is directly mounted on plate 212. Pinchers 14 and 24 move integrally. That is, the cutting apparatus of this arrangement is designed such that pinchers 14 and 24 of clamps 10 and 20 provided on the respective sides of the fiber cutting section are made integral by plate 212. This is the difference between the present cutting apparatus and the conventional cutting apparatus as shown in Figs. 1A-1C. Operation: In the first step of cutting optical fiber 40, first clamp 10 and second clamp 20 are released and optical fiber 40 is placed on clamp tables 12 and 22, as shown in Fig. 10A. Then, as shown in Fig. 10B, pinchers 14 and 24 made integral by plate 212 are simultaneously closed to clamp optical fiber 40 at the same time. Thereafter, scoring blade 52 is moved within a plane perpendicular to the axis of optical fiber 40 in the horizontal direction or the arched direction, to score the optical fiber at the desired portion. Then, pushing member 54 applies bending stress on the scored optical fiber 40 from the opposite side of the score to cut the fiber. Figs. 11A to 11C illustrate another arrangement which further has a third clamp 62 in addition to first and second clamps 10 and 20, and first fiber guide 72 and second fiber guide 80. Third clamp 62 comprises a clamp table 64 and pincher 66. Pincher 66 is freely openable and closable to clamp table 64, and, when closed, it clamps bare portion 44 of an optical fiber 40. Reference numeral 36 is a rubber member used to absorb the stress applied on glass portion 44 by pincher 66. In Figs. 11A to 11C, all clamps 10, 20 and 62 are integrally formed. However, clamp 10 may be separate from clamps 20 and 62 which sandwich the fiber portion to be cut. Reference numeral 72 is a first guide, which is provided on the rear side (on the side of sheathed portion 42) of first clamp 10 (see the arrow 74 in Fig. 11A for the rear and front side) and has a groove 76 provided to receive sheathed portion 42, as shown in the lower left cross section in Fig. 11A. Reference numeral 80 is a second guide provided on the front side (on the side of bare fiber 44) of first clamp 10, and the second guide 80 has a groove 82 provided to receive sheathed portion 42 and a slit 84 to receive bare fiber 44, as shown in the lower left and right cross sections in Fig. 11A. The groove 82 and slit 84 are formed to be continuous to each other. The cutting apparatus of Figs. 11A to 11C may be applied to cutting a taped multicore fiber. In this case, a stationary jig is attached to optical fiber 40 and is clamped by first clamp 10, and scoring blade 52 is moved horizontally in a plane perpendicular to the axis of the fiber, to score the bare fiber portion. Operation: Optical fiber 40 is set such that its sheathed portion 42 is fit in groove 76 of guide 72 and groove 82 of guide 80 and its glass portion 44 is fit in slit 84 of guide 80. Then, plate 212 is moved downward, thus causing pincher 14 of first clamp 10 to contact sheathed portion 42 of optical fiber 40 to thereby clamp the fiber in the direction perpendicular to the moving direction of scoring blade 52. Plate 212 is moved further down, causing second and third clamps 20 and 66 to simultaneously clamp optical fiber 40. Consequently, optical fiber 40 can be properly scored by scoring blade 52. Each of the first and second arrangements can be applied to both of single core and multicore optical fibers. Effects of the afore-mentioned arrangements: Since the pinchers of at least the clamps located on the respective sides of the optical fiber cutting section are formed integrally, the following effects are obtained. (1) The optical fiber can be clamped by a single operation, thus improving the operability. (2) A single opening/closing mechanism (such as a hinge) is sufficient for those two or three clamps, thus ensuring that the clamp structure can be simplified and can be made more durable and more compact. Figs. 12A to 12D illustrate the optical fiber and the clamps in the individual steps of an optical fiber cutting method. This method can easily prevent a score or crack from being made on the end face as a result that the cut ends of the optical fiber contact or hit against each other when these ends revert to the initial positions at which they are cut. Scoring blade 52 is moved in the direction perpendicular to the axis of bare fiber 44 to the optical fiber score at the desired portion (Fig. 12A). Then, pushing member 54 is moved to push the scored portion of the fiber from the opposite side of scoring blade 52 to cut the fiber (Fig. 12B). While bare fiber 44 cut by the pressure of pushing member 54 is in the pushed state (Fig. 12C), clamps 62 and 20 on the respective sides of pushing member 54 are slightly released so as to permit the optical fiber to move. Thereafter, pushing member 54 is retracted (Fig. 12D) to remove the optical fiber. While the cut optical fiber is still pushed by the pushing member, the clamps on respective sides of the pushing member are slightly released so as to permit movement of the optical fiber, and the pushing member is then retracted to remove the optical fiber. Therefore, the following effects are attained. (1) The end faces of the cut optical fiber do not strongly hit against each other, thus prevent a damage of the end face of the fiber to be used. (2) This method can be easily executed irrespective of the location of the pushing member, i.e., irrespective of whether the pushing member is positioned above the optical fiber or at the side thereof. The following explains an embodiment of a cutting apparatus for performing the above method. In Fig. 13 which is a plan view of the cutting apparatus with its lid fully open, reference numeral 252 is a main body of the cutting apparatus, and numeral 254 is a lid made openable and closable by means of a hinge 256 . Figs. 14A and 14B respectively illustrate the cross sections of the cutting apparatus with its lid 254 closed, taken along lines A-A and B-B of Fig. 13, while Figs. 15A and 15B respectively illustrate the cross sections of the cutting apparatus with its lid 254 slightly open, taken along lines A-A and B-B of Fig. 13. Tables 64 and 22 of clamps 62 and 20 are mounted on apparatus body 252 and pinchers 66 and 24 are attached to lid 254. Table 12 of clamp 10 is mounted on apparatus body 252 and pincher 14 is attached to the apparatus body by means of a hinge 258 (Fig. 13). Reference numeral 260 is a magnet, numeral 262 is a magnet-contact metal and numeral 264 is a compression spring. When lid 254 is closed, clamping force is given to clamps 62 and 20 by the attraction between magnet 260 and contact metal 262. The clamping force of first clamp 10 is given by the force of spring 15 in addition to the attraction between magnet 260 and contact metal 262. Pushing member 54 is mounted as follows. An arm 266 is swingably mounted on one side of apparatus body 252 by means of a support shaft 268 provided at the proximity of one end of the arm. Another arm 270 extending in the direction perpendicular to the axis of arm 266 is liftably mounted at the proximity of the other end of arm 266, and pushing member 54 is mounted on the bottom of the distal end of arm 270. Scoring blade 52 is horizontally movable under arm 270. Reference numeral 274 is a lever, which is swingably mounted on apparatus body 252 by means of a pin 276 and has one end section 278 contacting the bottom of lid 254 and the other end section 280 facing arm 266 with a slight gap 268 between end section 280 and the bottom of arm 266. Operation: After arm 270 is lifted up, lid 254 is opened and pincher 14 of clamp 10 is released, optical fiber 40 is set at a given position. Pincher 14 is closed, lid 254 is closed and optical fiber 40 is clamped by clamps 10, 62 and 20. Scoring blade 52 is moved in the direction perpendicular to the axis of fiber 40 to score bare fiber 44. Arm 270 is lowered to push down pushing member 54, thereby cutting bare fiber 44 at the score. At the time pushing member 54 is pushed down, arms 270 and 266 are simultaneously lowered. When arm 266 is lowered (Fig. 15A), its bottom contacts end section 280 of lever 274 to thereby lower the end section 280. As a result, the other end section 278 of lever 274 is moved up to lift up lid 254 against the attracting force of magnet 260, thereby slightly releasing clamps 62 and 20. Accordingly, bare fiber 44 and waste fiber 44A are permitted to be freely moved. When lid 254 is slightly lifted up to separate magnet 260 from contact metal 262 a little, the magnetic force is reduced. Therefore, even the pushing of pushing member 54 is stopped, lid 254 is kept slightly open by the force of spring 15 (Fig. 15B) to thereby keep clamps 62 and 20 slightly open. When pushing member 54 is retracted, bare fiber 44 and waste fiber 44A become straight due to their resilient force. Since clamps 62 and 20 are released at this time, bare fiber 44 does not hit against waste fiber 44A, thus preventing an undesirable score or crack from being made on the end face of the fiber. Even if bare fiber 44 and waste fiber 44A hit against each other, the collision is not strong enough (as bare fiber 44 and waste fiber 44A are not clamped at that time) to make any crucial damage. Then, arm 270 is lifted up, lid 254 and pincher 14 are opened, and optical fiber 40 is removed. The above cutting apparatus is also applicable to the following case. (1) Sheathed portion 42 is clamped by both of clamps 66 and 20 in the case shown in Figs. 12A-12C, a score is made by scoring blade 52 to the sheathed portion, and the sheathed fiber is then cut at the score by pushing member 54. (2) With sheathed portion 42 clamped by clamp 62 and bare fiber 44 clamped by clamp 20, the fiber is cut. According to the cutting apparatus of this embodiment, while the cut optical fiber is still pushed by the pushing member, the clamps on respective sides of the pushing member are slightly released so as to permit movement of the optical fiber, and the pushing member is then retracted to remove the optical fiber. Therefore, the following.effects are attained. (1) The end faces of the cut optical fiber do not strongly hit against each other, thus prevent a damage of the end face of the fiber to be used. (2) This method can be easily executed irrespective of the location of the pushing member, i.e., irrespective of whether the pushing member is positioned above the optical fiber or at the side thereof.

Claims: An optical fiber cutting apparatus comprising a plurality of clamps (10, 20, 62) for clamping an optical fiber (40) set straight, each of said clamps comprising a pincher (24, 66) and a table (22, 64), a plate member (254), a scoring blade (52) provided between two adjacent clamps (10, 62) of said plurality of clamps for making a score on said optical fiber (40) by moving within a plane substantially perpendicular to said optical fiber, and a pushing member (54) for pushing said optical fiber (40) from the opposite side of said score to cut said optical fiber, characterized in that said pushing member (54) is adapted to maintain a cutting position, after having cut the optical fiber, in which the cut ends (44, 44A) of the fiber are bent by the pushing member (54), and said two adjacent clamps (20, 62) are releasable to render the cut ends (44, 44A) of the optical fiber movable when the pushing member (54) is in said cutting position, wherein the pushing member (54) is movable to a retracted position after said two adjacent clamps (20, 62) are released. The cutting apparatus according to Claim 1, wherein one (10) of said two adjacent clamps is arranged to clamp a sheathed fiber portion (42) of said optical fiber (40) and the other clamp (62) clamps a bare portion (44) of said optical fiber. The cutting apparatus according to Claim 1, wherein two adjacent clamps (20, 62) clamp a bare fiber portion (44) of said optical fiber (40). The cutting apparatus according to Claim 1, 2 or 3, wherein said scoring blade (52) is mounted to move horizontally within said plane substantially perpendicular to said optical fiber (40) so as to score said optical fiber. The cutting apparatus according to Claim 1, 2 or 3, wherein said scoring blade (52) is mounted to move within said plane substantially perpendicular to said optical fiber (40) in a circumferential direction so as to score said optical fiber.

Inventors: OSATO YASUKUNI, SASAKI KATSUMI, SUDA HIROHISA, OSATO, YASUKUNI, SASAKI, KATSUMI, SUDA, HIROHISA, SASAKI, KATSUMI, FUJIKURADENSEN KABUSHIKIKAISHA, SUDA, HIROHISA, FUJIKURADENSEN KABUSHIKIKAISHA
Applicants: FUJIKURA LTD, FUJIKURA LTD.
Application year: 1988
Main classification: G02B6
IPC codes: G02B6