OPTICAL CONNECTOR

Abstract: An optical connector which is attached to the forward end of an optical fiber cord that includes an optical fiber (1) and a sheath (3) between which high-tensile material (2) is provided. The connector comprises a ferrule (9) to be attached to the forward end of the optical fiber, and a strip ring (7) whose tip position is restricted by the ferrule (9). The said optical connector is provided with a molded resin boot (11) on the rear half of the stop ring (7) to integrally join the high-tensile strength material (2) and the forward end of the sheath (3).

Description: The present invention relates to an optical connector for optically connecting jacketed optical fibers. As shown in Fig. 3, an optical fiber cord includes a jacketed optical fiber 1 formed of an optical fiber 1a covered by a coating 1b of nylon or the like, a tension member 2 of aramid fibers or the like arranged around the jacketed optical fiber 1, and a sheath 3 of polyvinyl chloride (PVC) covering these elements. An optical connector for optically connecting optical fiber cords is attached to an end portion of the jacketed optical fiber 1. This optical connector is assembled from a plurality of components. As shown in Fig. 4, for example, a rubber boot 4, ring 5, caulking ring 6, stop ring 7, and spring 8 are previously mounted, in the order named, on the optical fiber cord to which the optical connector is attached. The sheath 3 at the distal end portion of the optical fiber cord is removed, and a ferrule 9 is attached to the distal end of the exposed jacketed optical fiber 1. Then, the components 4 to 8 are successively pushed out toward the ferrule 9 in front, as indicated by the arrows, and are fixed to one another, and thereafter, a plug frame 10 is fitted on them, whereupon the optical connector is assembled. Conventionally, these operations are performed manually. In performing this assembling operation, the caulking ring 6 is staked so that the tension member 2 is caught and held between the caulking ring 6 and the stop ring 7, and the distal end of the sheath 3 is held between the ring 5 and the caulking ring 6, as shown in Fig. 5, whereby the tensile strength of a mounting portion of the optical fiber cord for the optical connector is secured. When the caulking ring 6 and the stop ring 7 are pushed out forward, in assembling this optical connector, the tension member 2 and the sheath 3 are inevitably caught between the jacketed optical fiber 1 and the stop ring 7 and between the jacketed optical fiber 1 and the caulking ring 6, respectively, as shown in Fig. 6. In the assembling operation for the optical connector, therefore, the tension member 2 and the sheath 3 must be drawn out of the stop ring 7 and the caulking ring 6, respectively, before staking the caulking ring 6. Having a wall thickness greater than that of the tension member 2, however, the sheath 3 cannot be easily drawn out of the caulking ring 6, so that the removal work is very troublesome. Thus, the assembling operation for the optical connector takes trouble, so that the productivity is low, and moreover, the assembling operation for the optical connector cannot be mechanized. The present invention has been contrived in consideration of these circumstances, and its object is to provide a high-productivity optical connector which attached to an end portion of an optical fiber cord, and whose assembling operation is easy and can be mechanized. Viewed from one aspect the present invention provides an optical connector as defined in claim 1. The resin boot, which preferably integrally fixes the respective distal ends of the tension member and the sheath by the insert molding method, functions as a rubber boot in a conventional optical connector. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figs. 1 and 2 show one embodiment of an optical connector according to the present invention, in which Fig. 1 is a sectional front view of the principal part of the optical connector, and Fig. 2 is a perspective view showing the way of molding a resin boot provided on the respective distal ends of a tension member and a sheath and integrally fixing them; and Figs. 3 to 6 illustrate the construction of a conventional optical connector, in which Fig. 3 is a front view showing the construction of an optical fiber cord, Fig. 4 is an exploded view for illustrating the assembly of the optical connector, Fig. 5 is a sectional view of the principal part showing the way a tension member is held by means of a stop ring and a caulking ring, and Fig. 6 is a sectional view of the principal part showing the positional relationships between the stop ring, caulking ring, and tension member. Referring now to Figs. 1 and 2, one embodiment of the present invention will be described in detail. In the description to follow, like reference numerals are used to designate the same components as those of the conventional optical connector described before. In an optical connector of the present invention, as shown in Fig. 1, a spring 8 is interposed between a ferrule 9, which is attached to the distal end of a jacketed optical fiber 1, and a stop ring 7 arranged adjacent to the ferrule 9, and a resin boot 11 is provided on the rear half of the stop ring 7. This resin boot 11, which is molded by the insert molding method, serves to integrally fix the respective distal ends of a tension member 2 and a sheath 3, and to protect the rear half of the optical connector. A resin plug frame (not shown) is fitted on the front half the stop ring 7, which has the resin boot 11 molded thereon. The optical connector with this construction is assembled in the following manner. First, the stop ring 7 and the spring 8 are previously mounted on an optical fiber cord. Subsequently, the sheath 3 at the distal end portion of the optical fiber cord is removed for a predetermined length, and the ferrule 9 is attached to the distal end of the exposed jacketed optical fiber 1. Thereafter, the stop ring 7, along with the spring 8, is pushed out toward the ferrule 9 in front so that the distal end of the stop ring 7 abuts against the rear end of the ferrule 9. Then, the respective distal ends of the tension member 2 and the sheath 3, caught between the jacketed optical fiber 1 and the stop ring 7 as the stop ring 7 is pushed out, are drawn out of the stop ring 7. Subsequently, the ferrule 9, engaged with the distal end of the stop ring 7, is mounted, along with the jacketed optical fiber 1, on a lower mold 12 which has a recess 12a, corresponding in shape to the resin boot 11, and an injection groove 12b, as shown in Fig. 2. Then, an upper mold 13, which has a recess (not shown) and an injection groove 13b similar to those of the lower mold 12, is placed on the lower mold 12 in the manner indicated by dashed lines. Thereafter, a resin is poured into both molds 12 and 13 through a passage defined by the injection grooves 12b and 13b as a runner, whereupon the resin boot 11 is molded on the rear half of the stop ring 7. In this manner, the respective distal ends of the tension member 2 and the sheath 3 of the optical fiber cord are integrally fixed by means of the resin boot 11. Subsequently, the plug frame (not shown) is fitted on the front half the stop ring 7, whereupon assembling the optical connector is completed. Thus, in the optical connector of the present invention, the respective distal ends of the tension member 2 and the sheath 3 are buried in the resin of the molded resin boot 11 and fixed integrally with the resin boot 11. Unlike the conventional optical connector, therefore, the optical connector of the invention does not require use of the ring 5 and the caulking ring 6. In the optical connector of the present invention, as is evident from the above description, the resin boot, which integrally fixes the respective distal ends of the tension member and the sheath, is provided on the rear half of the stop ring by molding, so that the resin boot can be molded by only drawing out the tension member and the sheath, caught between the stop ring and the jacketed optical fiber, from the stop ring, and therefore, assembling the optical connector is easy. Further, the caulking ring or ring for holding the tension member and the sheath need not be used, so that the components used can be reduced in number. As compared with the case of the conventional optical connector, therefore, the productivity is much improved, and assembling the optical connector can be mechanized and automated. Since the tension member and the sheath are buried in the resin boot, moreover, the optical connector of the invention can enjoy various industrial applications, taking advantage of, for example, its tensile strength higher than that of the conventional optical connector in which the tension member and the sheath are fixed by caulking.

Claims: An optical connector provided on an optical fiber cable having a jacketed optical fiber (1) covered by a sheath (3) with a tension member layer (2) therebetween, the optical connector comprising a ferrule (9) provided on a distal end of the jacketed optical fiber (1) and a stop ring (7) whose distal end position is delimited by said ferrule (9), characterised by a resin boot (11) molded on to the rear half of said stop ring (7) thereby to fix integrally the respective distal ends of said tension member layer (2) and said sheath (3) about said stop ring (7) so that they remain on the stop ring even when subjected to tension. An optical connector according to claim 1, wherein said molded resin boot (11) has been provided on the distal end of said optical fiber cable by insert molding.

Inventors: SHIBATA NOBUYUKI, SHUZUKI KENJI, YUGUCHI REN-ICHI, SHIBATA, NOBUYUKI, SHUZUKI, KENJI, YUGUCHI, REN-ICHI, SHIBATA, NOBUYUKI, THE FURUKAWA ELEC. CO., LTD., SHUZUKI, KENJI, THE FURUKAWA ELEC. CO., LTD., YUGUCHI, REN-ICHI, THE FURUKAWA ELEC. CO., LTD.
Applicants: FURUKAWA ELECTRIC CO LTD, THE FURUKAWA ELECTRIC CO., LTD.
Application year: 1991
Main classification: G02B6
IPC codes: G02B6