JP2625256B2 - Optical fiber connector having a contacting tip - Google Patents

Description

BACKGROUND OF THE INVENTION A common method of connecting a pair of optical fibers is to hold their ends in substantial contact and precise alignment. Precise alignment is achieved with one slidable movement along the sleeve until the fiber tips are substantially mated.
This is accomplished by providing a sleeve with a precision internal cylindrical surface that securely receives the ferrules attached to the ends of the two fibers to guide one ferrule. U.S. Pat. No. 4,140,367 to Makuch describes a connector system of this type.
The alignment sleeve must be precisely formed by machining and is not conductive because it is manufactured by injection molding of plastic. U.S. Patent No. 4,964,6 by Lappohn
Another method disclosed in U.S. Pat. No. 90 describes one configuration in which an alignment sleeve slidably receiving a ferrule attached to the ends of two fibers to be coupled includes an intermediate sleeve portion having a slit. And the area between the slits is compressed inward against the two ferrules to align them. The slitted sleeve portion is of a length that can be substantially lengthened to allow the inner surface between the slits to remain substantially cylindrical despite being bent inward to squeeze the ferrule. There must be. The ferrules are biased against each other by a spring, which requires the optical fiber to be able to slide in and out of the rear end of the ferrule,
The ferrule prevents securing the rear end of the ferrule with respect to the connector housing.

Conventional optical fibers that use a glass core have a diameter of 0.
Very thin at 003 inches. A more recent approach is to use plastic fibers having a 1 millimeter (about 0.039 inch) diameter optical transmission core. Such a plastic fiber allows the use of low-cost connectors due to the important parts formed by plastic injection molding. However, plastic injection molding generally produces less accurate parts than those obtained by metal machining. It is relatively small and ensures accurate alignment of the optical fibers that are substantially mated despite substantial errors in the manufacture of the connector portion;
A fiber optic connector system that avoids the need for the rear end of the fiber optic to slide with respect to the connector is of considerable value.

SUMMARY OF THE INVENTION In accordance with one embodiment of the present invention, a fiber optic connector system allows for accurate alignment of actual mating optical fibers in a connector at a reasonable cost, with a fiber optic section extending behind the connector. Can be fixedly arranged with respect to the connector housing. Each connector includes a fiber optic device that includes a ferrule that is held around the front end of the fiber by shrinking. The first connector housing has an alignment sleeve having a slot dividing the front portion of the sleeve into a pawl having a free front end. The second connector housing deflects the free ends of the claws radially inward with respect to the outside of both ferrules;
This forms a deflector detent to accurately align the ferrule. The inner surfaces of the pawls preferably initially extend with a slight taper, and each pawl preferably has an elongated projection that joins the ferrules with substantially straight contact.

One fiber optic device of the connector includes a rear ferrule secured to the optical fiber at a distance behind the front ferrule to leave a noticeable length of bend in the optical fiber between the connectors. . The rear ferrule is held against rearward movement, but the front ferrule can slide backward when the optical fibers are joined together, and the reduction in the distance between the ferrules is achieved by bending the optical fiber. A coil spring surrounds the portion of the optical fiber that is placed between the ferrules to bias the ferrules apart.

The novel features of the invention are set forth with particularity in the appended claims. The present invention will be better understood from the following description, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fiber optic connector system constructed in accordance with the present invention showing the plug and receptacle connectors shown separately.

FIG. 2 is a longitudinal sectional view of the connector system of FIG. 1 with the connectors fully mated.

FIG. 3 is a longitudinal sectional view of the receptacle connector of the system of FIG.

 FIG. 4 is a longitudinal sectional view of the plug connector of FIG.

FIG. 5 is a front end view of the receptacle connector of FIG.

 FIG. 6 is a front end view of the plug connector of FIG.

FIG. 7 is an enlarged view of the connector system of FIG. 2 shown at the beginning of a pawl deflection.

 FIG. 8 is a cross-sectional view of one of the claws of FIG.

FIG. 9 is an isometric view of a tool used to mount and remove the fiber optic device from the housing of the system of FIGS.

FIG. 1 shows a fiber optic connector system 10 having plug and receptacle connectors 12, 14 having front ends 16, 18, respectively, and which can be coupled by moving each connector in a forward direction Fp, Fr. Each connector includes a housing 20,22 and a fiber optic device 24,26 mounted to the housing. When the connector is mated, the front end 30 of the optical fiber 32 of the plug fiber optic device substantially contacts the front end 34 of the optical fiber 36 of the receptacle fiber optic device. The tips should be in substantial contact by placing them very close (eg, within 0.1 mm) for good coupling, but the tips of large diameter (eg, 1 mm) optical fibers will touch each other No need.

As shown in FIG. 2, the plug fiber optic device 24 surrounds the optical fiber 32 and connects the fiber to the rear portion 42
Includes a front ferrule 40 which is securely supported and attached by compressing (crimping) its ends. The receptacle fiber optic device 26 includes a front ferrule 44 that is supported and attached to the fiber by compressing the end of the rear portion 46 of the ferrule into the fiber. In addition, the fiber arrangement 26 includes a rear ferrule 50 that is compressed at the end to a fiber at a distance A behind the front ferrule, leaving a long section 36A of optical fiber therebetween. The device includes a coil spring 52 having opposite ends compressing shoulders 54, 56 formed by flanges 60, 62 formed on the front and rear ferrules, respectively.

The rear ferrule 50 of the receptacle optical fiber device is
The holder, which is a part of the receptacle housing 22, is prevented from moving backward in the direction Rr. The front ferrule 44 of the receptacle fiber device can slide back and forth in directions Rr and Fr within a guideway 64 formed in the receptacle housing. The front facing shoulder 64 on the ferrule has the rear facing shoulder on the housing
Until it touches 64, the spring 52 and the elasticity of the optical fiber push the front ferrule in the forward direction. The front ferrule 44 has a front end portion 34 of a receptacle fiber 36 and a plug fiber 32.
Can move backward when it comes into contact with the front end 30 of the vehicle.

The connector is mated by inserting the front portion of plug housing 20 into the front portion of receptacle housing 22. During such insertion, the tips 30, 34 of the two fibers come into contact with each other and the tip 30 of the receptacle fiber moves slightly in the direction Rr. The front ends 32B, 36B of the two fibers must be very precisely aligned to effectively couple the two fibers such that a very high percentage of the light in one of them will propagate to the other fiber. . Such alignment is achieved by the alignment sleeve portion or sleeve 70 of the plug housing.
As shown in FIG. 4, the alignment sleeve 70 is
, But with a slight gap between them allowing a slight tilting of the ferrule. The front portion 74 of the sleeve may include three pawls 80-84, or a free end 92.
It has three slits or slots 76 that divide it into elongated sleeve portions shown to have. The inner surface 86 of the sleeve forward portion has a taper in the molded non-deflected direction, the taper being formed such that the inner surface of the pawl gradually increases in diameter at the forward portion. this is,
An inner surface of each pawl extending at an angle B from the axis 88 of the plug results. FIG. 7 shows portions of the plug and receptacle approaching each other during bonding. Initially, a radially outer portion 90 of the pawl tip mates with a pawl coupling surface 94 of a receptacle deflector 96 of the receptacle housing.
Further, the forward movement of the plug in the direction Fp is such that the pawl inner surface 86 accurately aligns the forward portions of the two ferrules,
The pawls are deflected radially inward until they press against the outside of the front ferrule portions 97, 99 to accurately align the tips 30, 32 of the two optical fibers.

The exact alignment of the front parts 97,99 of the two ferrules
This is achieved because the inner surface 86 of each pawl extends at least substantially at the portion joining the front portion of the ferrule. Forming a substantially straight line on a precision injection molded plastic part or other part is relatively simple.
As a result, the straight inner surface of the pawl is the front part of both ferrules in three places spaced around the ferrule
The 97,98 are pressed radially, and the alignment of the two ferrules, each at three locations spaced around their circumference, is performed accurately. At least the receptacle front ferrule 44
It can be shifted slightly radially in the sliding guideway 64 to be in the front ferrule position with precise alignment. Pawls are formed in the non-deflected position, and their inner surfaces are at an angle B as small as 3 ° from parallel to the axis 88 of the plug (see FIG. 4).
Extending. The fact that the pawls have to undergo only small deflections will result in the correct deflection of the pawls.

Preferably, a pawl deflector 96 is formed having a substantially cylindrical rear portion 100 that securely receives the deflected pawl. Because the outer portion 90 of one pawl tip is slightly rounder than the other pawl tip, the tapered pawl coupling surface 94 does not simultaneously deflect all pawls radially inward by the same amount. The surface of the cylindrical rear portion 10 of the pawl deflector is formed as a precise cylindrical shape like the outer surface 102 of the front end 103 of the pawl. This is so that all three pawls surround the front part of the two ferrules very closely when the pawls are sufficiently deflected and their front ends are located within the cylindrical rear part 100 of the deflector. To be substantially equally deflected.

It is possible for the ferrules to form their inner surface as being cylindrical. However, as shown in FIG. 8, it is preferred to form a protrusion 104 on the inner surface 86 of each pawl. The projection 104 is at least a front part of the nail,
And preferably a constant cross section along the entire length of the alignment sleeve. Protrusion 104 provides a narrow innermost portion 106 that mates with a ferrule that is substantially in line contact therewith. Forming the pawls so that the innermost portion 106 extends along the line is such that they are positioned exactly inside the cylinder of the same diameter as the outside of the ferrule, without distortion, inside the entire pawl. It is simpler than forming a surface. It should be noted that the pawls are relatively short in length, approximately equal to three times the diameter of each ferrule front section. The resilience of the pawls with free front ends allows such relatively short pawls to be used, and when they are deflected they are located very close around the front ends of the two ferrules Guarantee.

As shown in FIG. 3, the front ferrule of the receptacle
Flange 60 on 44 first contacts shoulder 66 on the receptacle housing. When the optical fiber tip 34 contacts the plug fiber tip, the front ferrule 44
Moves slightly backwards. Such rearward movement is effected by a fiber section 3 extending between the front and rear ferrules 44,50.
Bend 6A away from the axis 98 of the receptacle connector to match the shortened distance between the ferrules. It is preferred to provide a coil spring 52 to ensure that the front ferrule is pressed forward firmly, but it is also possible to rely on the elasticity of the optical fiber itself.

The plug and receptacle housing do not produce as precise a part as is achieved by metal machining, but are formed by very low cost injection molding. The receptacle housing 22 (FIG. 3) has two parts: a main housing part 110 and a pin part 11 whose front end is fixed to hold the deflector of the pawl.
Preferably, a second deflector 96 is formed which is held in the main part by the two. The pawl deflector 96 is preferably formed of a low friction material such as polypropylene or Teflon to facilitate sliding movement of the pawl of the alignment sleeve. Also plug housing 20
(FIG. 4) is preferably formed with a main portion 114 and a separation sleeve portion 116. The ferrule is preferably formed by machining a metal, such as brass, and care is taken that the front portion of the entire front ferrule has equal diameter and concentric inner and outer surfaces.

The connector system facilitates securing each connector to the optical fiber in the field in a manner that minimizes the need for special tools. To assemble the plug connector (FIG. 4), the operator first cuts the end of the optical fiber and inserts the end of the fiber into the ferrule 40 until the fiber tip projects slightly therefrom. This is preferably accomplished by bending the end of the rear portion 42 of the ferrule at 120 to hold the ferrule in place. It should be noted that the plastic optical fiber includes a transparent plastic core 122 usually surrounded by an opaque plastic jacket 124. The cutting marks are erased with sandpaper and the fiber tips are polished with sandpaper to form a substantially flat fiber tip. The tip of the fiber polished with sandpaper is preferably located flush with the front end of the ferrule, so the ferrule should be sandpaper polished with the fiber tip substantially flat and perpendicular to the fiber axis. To ensure. Fine sandpaper (eg, over 600 grids)
Is used to sand the fiber end with sandpaper last. Fibers with ferrules
The retaining finger 62 is inserted behind the plug housing 20 until it contacts the rear of the ferrule flange 126. The plug connector is fully assembled.

The receptacle connector 14 (FIG. 3) is assembled by sliding the ferrules 50,44 over a fiber having a spring 52 therebetween. Forward ferrule 44, crimp 13
At 0, the end of the rear portion 46 of the ferrule is held on the fiber by shrinking and bending it. The rear ferrule is slid forward to a position where the fiber 36A is slightly bent and the end is crimped onto the fiber. Although it is possible to crimp the end of the rear ferrule in a position where the optical fiber is not initially bent, a slight deflection at the beginning is preferred as it facilitates additional deflection when the connectors are mated. The receptacle end of the fiber is sanded with sandpaper to be substantially flat and smooth.

To assemble the connector, the plug connector is inserted into the receptacle connector until a pair of latches 140 on the plug connector are fully engaged with the projections 144 on the receptacle connector, and the holes 146 in the latch receive the projections and the projections 144 Combines with upper rear shoulder 148. The connectors are fully mated. As discussed above, during mating, the pawl of the plug connector is deflected inward, so that the inner surface of the pawl is located very close to the forward portions of the two ferrules for accurate alignment. During such a connection, the front ferrule of the receptacle connector is moved slightly backward.

The tools required for installation or removal of each connector include crimping tools commonly used by workers installing and repairing wires and cables, conventional sandpaper, and a very low profile shown at 140 in FIG. Equipped with special tools at cost. The tool 140 is a very precision part of a flexible plastic injection molded, having a slot 142 to allow it to slide over the optical fiber. The tool 140 is used to remove the ferrule by squeezing the tool and its front end 14
4 the retainer pawls 62 to deflect the pawls outside the passage
(FIG. 4), thereby removing the ferrule. Tools and retainers of this type are well known in the prior art.

Thus, the present invention provides a fiber optic connector system that is small, low cost, and easily mountable in the field. One of the connectors has an alignment sleeve that extends forward of the ferrule and has a forward end having a slot that divides into a pawl having a free forward end.
The inner surface of the pawl sleeve is preferably tapered to have progressively larger diameters at a forward location along it. The other connectors have pawl deflectors that mate with the pawl tips when the connectors are mated so that they deflect the claws radially inward until they firmly mate the front ferrules of both connectors. The free forward ends of the pawls facilitate their deflection using relatively short length pawls so that small connector structures are easily obtained. One fiber optic device of the connector preferably includes two ferrules attached to the fiber, the rear ferrule being held against rearward movement by the connector housing, and the front ferrule being slidable rearward. Backward sliding of the front ferrule is accommodated by flexing of the fiber optic section extending between the ferrules.

While particular embodiments of the present invention have been described and illustrated herein, it will be recognized that modifications and changes will readily occur to those skilled in the art, and the claims will cover such modifications and equivalents. Is intended.

Claims (12)

(57) [Claims] An optical fiber device (24, 26) in each of the housings (20, 22), each fiber optic device including a ferrule having a front and a rear portion, wherein the plug and receptacle ferrule are formed of an optical fiber. Includes mating plugs and receptacle connectors (12, 14) attached to and surrounding the ends (32B, 36B), respectively, which improve the mechanism for precisely aligning the ferrule to accurately align the optical fiber. In the fiber optic connector system, the plug housing (20) has a plastic molded alignment sleeve (70) closely surrounding the front portion (97) of the plug ferrule, the alignment sleeve having a free front end (92). A plurality of pawls (80, 82, 84) having a plurality of slots (76) dividing the forward portion of the sleeve; The receptacle is coupled to the free forward end of the pawl and deflects the plug and receptacle housing radially inwardly so that the pawl is at least coupled to the front portion (9) of the receptacle ferrule.
A fiber optic connector system comprising a deflector (96) having a pawl coupling surface (94) configured to deflect the pawl inward until closely mating about 9). 2. The sleeve inner surface (86) includes a plurality of radially inwardly extending projections (106), one of the projections joining the front portions of both the plug and the receptacle ferrule. Extending along each said pawl,
The connector of claim 1 wherein the radially innermost edge of each projection is narrower than the remainder of the pawl. 3. The deflector (96) for said pawls has a forward portion tapered inwardly so as to progressively decrease in diameter toward a rearward position, and in a fully inwardly deflected position. The connector of claim 1 having a substantially cylindrical rear portion for receiving a front end of said pawl for retaining. 4. An optical fiber device comprising: a first ferrule fixed to one end of the optical fiber; and a first ferrule fixed to one end of the optical fiber and spaced apart from the first ferrule by a same distance. A second ferrule fixed to the optical fiber, the one of the fiber optic devices further including a spring biasing the first and second remote ferrules; A portion of the optical fiber extending between the second ferrules is bendable, and one of the connector housings holding the one of the optical fiber devices is moved forward and rearward of the ferrule. Having first and second shoulders respectively in contact with the first and second ferrules to limit each other, wherein the first ferrule is rearward during mating of the connector. The first ferrule is slidable in the housing with respect to the second ferrule so as to be deflected, and the fiber optic portion is configured to deflect such a first ferrule.
2. The connector of claim 1, wherein the connector is bent to accommodate the rearward deflection of the ferrule. 5. A connector having a plug connector (12) and a receptacle connector (14), wherein each connector has a housing (20, 22) and an optical fiber (32, 36) having a front end (32B, 36B). , Each having an optical fiber device (24, 26) having a front ferrule (40, 44) surrounding and holding the front end of the optical fiber, wherein the first housing (20) of the housings is a free front end. An alignment sleeve (70) having a slot (76) forming a plurality of claws (80, 82, 84) having a (92), said sleeve comprising a front ferrule (40) of the first connector (12). Closely received, the free front end of the pawl is connected to the front ferrule (4
0) extending forwardly of the front end of said second housing (22), said pawl (80, 82, 84)
And both front parts (97, 99) of said ferrule
A fiber optic connector system having a deflector (96) for a pawl positioned to closely enclose and press against. 6. The system of claim 5, wherein said sleeve is a molded portion having an axis and molded to have an interior surface of said pawl diverging in a forward radially outward direction. 7. The sleeve of claim 5, wherein the sleeve includes an inner projection having a narrow radially inner surface for substantially linear contact with both the shaft and the ferrule. system. 8. A deflector (96) for said pawls having a substantially cylindrical rear surface positioned to surround said pawls after their forward ends have been sufficiently deflected radially inward. The system of claim 5, comprising: 9. A mating plug and receptacle connector (12) connecting the front ends (30, 34) of a pair of optical fibers and having a housing (20, 22) and an optical fiber device (24, 26) respectively in the housing. , 14), each fiber optic device includes a ferrule (40, 44) having a forward portion (97, 99), and a plug and receptacle ferrule surrounds the optical fiber and around its ends (32B, 36B) respectively. A fiber optic connector system mounted and including an improved mechanism for precisely aligning the ferrule for accurate alignment of the optical fiber, wherein the plug housing includes an alignment sleeve (70) closely surrounding a forward portion of the plug ferrule. The alignment sleeve has a forward portion (74) of the sleeve with a free forward end (92) and a straight ferrule-coupled inner surface (86). A plurality of slots (76) for dividing into a plurality of claws (80, 82, 84), wherein the receptacles have inner pawls until the pawls closely surround at least the front portion of the plug ferrule. A pawl coupling surface (94) coupled to the free forward end of the pawl to cause deflection and configured to deflect the plug and receptacle housing radially inward when coupled; An inner surface (86) of the sleeve includes a plurality of radially inwardly extending projections (106), one of the projections being both a plug and a receptacle ferrule. A fiber optic connector extending along each of said pawls for mating the front portions of the pawls, wherein the radially innermost end of each projection is narrower than most of the rest of the pawls. system. 10. A front end of a pair of optical fibers (30, 34).
And a mating plug and receptacle connector (12, 14) having a housing (20, 22) and a fiber optic device (24, 26) respectively in the housing, each fiber optic device having a front portion (97, 99). A plug and receptacle ferrule surrounding the optical fiber and each having a ferrule (40, 44) attached thereto around its end (32B, 36B) for accurately aligning the ferrule to precisely align the optical fiber The plug housing includes an alignment sleeve (70) that closely surrounds a front portion of the plug ferrule, the alignment sleeve defining a free front end of the sleeve front portion (74). A plurality of slots dividing into a plurality of claws (80, 82, 84) having a section (92) and a straight ferrule coupling inner surface (86). (76) wherein the receptacle is coupled with a free forward end of the pawl such that the pawl produces an inward pawl deflection until the pawl at least closely surrounds and couples a forward portion of the plug ferrule; A deflector (96) having a pawl coupling surface (94) configured to deflect the plug and receptacle housing radially inward when coupled; the deflector of the pawl progressively Substantially having a forward surface (94) tapered inwardly to decrease in diameter toward a rearward position and receiving the forward end of the pawl to hold them in a fully inwardly deflected position. An optical fiber connector system having a cylindrical rear portion (100). 11. The front ends (30, 34) of a pair of optical fibers.
And a mating plug and receptacle connector (12, 14) having a housing (20, 22) and a fiber optic device (24, 26) respectively in the housing, each fiber optic device having a front portion (97, 99). A plug and receptacle ferrule surrounding the optical fiber and each having a ferrule (40, 44) attached thereto around its end (32B, 36B) for accurately aligning the ferrule to precisely align the optical fiber The plug housing includes an alignment sleeve (70) that closely surrounds a front portion of the plug ferrule, the alignment sleeve defining a free front end of the sleeve front portion (74). A plurality of slots (80, 82, 84) having a portion (92) and a direct ferrule-bonded inner surface (86); (76) wherein the receptacle is coupled with a free forward end of the pawl such that the pawl produces an inward pawl deflection until the pawl at least closely surrounds and couples a forward portion of the plug ferrule; A deflector (96) having a pawl coupling surface (94) configured to deflect the plug and receptacle housing radially inward when the plug and receptacle housing are coupled, wherein the pawl is initially at an angle ( B) is formed to have a straight internal surface (86) that branches off at B) and is deflected to extend parallel to each other when deflected inward to join at least the forward portion of the plug ferrule. An optical fiber connector system comprising: 12. A front end of a pair of optical fibers (30, 34).
And a plug and receptacle connector (12, 22) having an optical fiber respectively including a housing (20, 22) and a front ferrule (40, 44) held around the corresponding optical fiber front end. 14), wherein the first housing (20) includes an alignment sleeve (70) having a slot forming a plurality of elongated sleeve portions (80, 82, 84), wherein the sleeve comprises the first housing (20). A front ferrule of the connector is received proximately, the elongate sleeve portion extends forward of the front ferrule in the first connector, and the second housing mates with the elongate sleeve portion to forward both ferrules. A fiber optic connector system having a deflector (96) positioned to closely surround and press a portion, wherein the sleeve comprises a shaft (88). And the optical fiber connector system which comprises said elongated sleeve projections including the protruding portion of the inwardly (106) respectively having both the substantially linear contact is to narrow the radially inner surface of the ferrule.