Contact retention arrangement

A contact retention arrangement for a fiber optic connector is disclosed in which the retention element for the ferrule connected to the fiber optic cable is formed or shaped with an integral spring which maintains mating ferrules in positive abutment with each other. The contact retention element may either be a contact retention clip mounted in the wall of the contact passage, or a retention clip carried by the ferrule. In the latter arrangement, the clip is designed so that it may be released from either the front or rear of the connector body. The contact retention arrangement may also be used in an electrical connector.

BACKGROUND OF THE INVENTION 
The present invention relates generally to a connector and, more 
particularly, to a contact retention arrangement for the contact element 
of a connector which is capable of exerting a resilient force on the 
element. 
While the present invention will be primarily described herein as being 
useful for fiber optic connectors, it may also apply to electrical 
connectors. 
U.S. Pat. No. 3,947,182 to McCartney discloses a contact retention 
arrangement for a fiber optic connector in which the ferrule is slidably 
mounted in a sleeve that is removably retained in a contact passage by a 
contact retention clip mounted in the wall of the passage. A resilient 
O-ring trapped between the front of the sleeve and a rearwardly facing 
shoulder on the ferrule is compressed when the ferrule slides rearwardly 
in the sleeve upon engagement of with a mating ferrule in a second 
connector member. Compression of the O-ring exerts a resilient forwardly 
directed force on the ferrule, maintaining the mating ferrules in firm 
abutment so as to maximize light transmission through the connector at the 
interface of the mating ferrules. The O-ring also absorbs mating connector 
tolerances. 
Pending application of L. M. Borsuk, et al. entitled "Fiber Optic Contact", 
Ser. No. 474,755, filed Mar. 14, 1983, now U.S. Pat. No. 4,747,658, 
assigned to the assignee of the present application, discloses a contact 
retention arrangement somewhat similar to that disclosed in the McCartney 
patent in that the ferrule is retained in the connector body by a contact 
retention clip and a resilient means is provided for urging the ferrule in 
the forward direction, except in this case the resilient means is a coil 
spring rather than an O-ring. 
U.S. Pat. No. 4,595,251 to Moulin discloses a fiber optic connector in 
which the contact retention clip is mounted on the ferrule, rather than in 
the contact passage. As seen in FIG. 14 of the Moulin patent, the ferrule 
is slidable in a collar which cooperates with the contact retention clip 
and a shoulder in the contact passage to releasably retain the ferrule in 
the passage. Bellville springs are disposed between the collar and a 
rearwardly facing shoulder on the ferrule which resiliently urge the 
ferrule in the forward direction when the ferrule is pushed rearwardly 
through the collar upon engagement with a mating ferrule. 
U.S. Pat. No. 4,178,068 discloses a fiber optic connector in which the 
ferrule is slidable in a contact retention clip having outwardly extending 
retention fingers that engage a shoulder in the wall of the contact 
passage for releasably retaining the ferrule in the passage. A coil spring 
is disposed between the front of the contact retention clip and a 
rearwardly facing shoulder on the ferrule for exerting a resilient 
fowardly directed force on the ferrule to maintain it in firm abutment 
with an opposed ferrule when two mating halves of the connector are 
interengaged. 
In each of the prior art connectors discussed above, there is provided a 
contact retention clip and a separate spring member which adds to the 
complexity and expense of the connector. Further, in each of such 
connectors the contact retention clip may be released from only one end of 
the connector. 
It is one object of the present invention to provide a contact retention 
arrangement for a contact element which produces a resilient force on the 
element, in a simpler and less expensive manner. 
It is another object of the invention to provide a contact retention 
arrangement for a contact element which may be released from either the 
front or rear of the connector. 
SUMMARY OF THE INVENTION 
According to a principal aspect of the present invention, there is provided 
a contact retention arrangement for a fiber optic connector in which a 
contact retention clip, which is either mounted in the wall of the contact 
passage or on the ferrule of the connector, is formed with an integral 
spring capable of producing significant axial compression upon rearward 
movement of the ferrule in the passage so that the spring maintains mating 
ferrules in the connector in positive abutment with each other. With the 
retention clip being formed or shaped to provide its own spring element, 
it will be appreciated that a separate spring element such as used in 
prior art connectors and disclosed in prior art patents is eliminated, 
thereby reducing the number of parts required in the connector and the 
cost of manufacture thereof. 
According to another aspect of the present invention, there is provided a 
contact retention arrangement for a fiber optic connector in which the 
contact retention clip is mounted on the fiber optic ferrule. The clip 
embodies a radially resilient retention element having a first section 
that extends from the clip body at an angle to an annular rib portion that 
projects into an annular groove in the contact passage, and a second 
section that extends from the rib portion at an angle and direction 
opposite to the first section. By this arrangement, a contact release tool 
may be inserted into either end of the contact passage to engage one of 
the angular sections of the retention element to deflect the element 
radially inwardly thereby withdrawing the rib from the groove. 
According to a further aspect of the invention, the above mentioned contact 
retention arrangements may be used in electrical connectors containing 
slidably mating pin and socket contacts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings in detail, wherein like reference characters 
designate like or corresponding parts in FIGS. 1-11, there is shown in 
FIGS. 1-5 the first embodiment of the invention. As seen in FIG. 2 the 
connector of the present invention, generally designated 20, comprises a 
first connector member 22 and a mating second connector member 24. The 
connector member 22 comprises a body having a front part 26 and a rear 
part 28. A contact passage 30 extends through the two parts 26 and 28. A 
hollow fiber optic ferrule 32 is mounted in the passage 30. Normally the 
connector body will contain a plurality of passages (not shown) each 
connecting a ferrule. The ferrule is shwon as being connected to a fiber 
optic cable 34 which extends from the rear 36 of the passage through the 
ferrule to its forward mating end. 
A forward part 38 of the ferrule has a reduced diameter. An alignment 
sleeve 40 is mounted on the forward part 38 of the ferrule. The sleeve 
projects forwardly from the front 42 of the contact passage for slidably 
receiving therein the forward part of a mating ferrule 32' mounted in the 
second connector 24. 
An annular groove 44 is formed in the wall of the passage 30. The groove 
extends from a forwardly facing shoulder 46 to the front face 48 of the 
rear part 28 of the connector body. The ferrule 32 is formed with an 
outwardly extending annular flange 50 which is normally disposed in the 
groove 44 immediately behind the rear face 52 of the front part 26 of the 
connector body. 
A contact retention clip 54 is mounted in the groove 44 behind the flange 
50 on the ferrule. The cliop has a circular body 55. The rear 56 of the 
clip body bears against the shoulder 46 in the contact passage. Like 
conventional contact retention clips such as disclosed in the 
aforementioned McCartney patent, the clip 54 has a plurality of radially 
resilient contact retention fingers 58, three being shown in FIGS. 3 and 4 
by way of example only. The fingers extend forwardly and inwardly from the 
clip body 55 so that their terminal ends 60 bear against the rear of the 
flange 50 thereby retaining the ferrule in the contact passage 30 in a 
forward position, that is, in a position wherein the flange 50 is 
immediately adjacent to the rear face 52 of the front part 26 of the 
connector body. When the ferrule 32 is initially pushed into the contact 
passage from the rear 36, flange 50 will deflect the fingers 58 outwardly 
until the flange passes the terminal ends 60 of the fingers, whereupon the 
fingers will snap inwardly to the position illustrated in FIG. 1 where 
they firmly retain the ferrule in its forward position. In order to 
release the ferrule so that it may be withdrawn from the contact passage, 
a suitable tubular tool of a type well known in the connector industry 
(not shown) is inserted into the rear of the contact passage to deflect 
the fingers 58 radially outwardly so that the flange 50 can pass freely 
through the clip and out the passage. 
According to the present invention, the contact retention clip 54 is formed 
with an integral spring which is axially compressed when the ferrules 32 
and 32' abut each other upon interengagement of the first and second 
connector members 22 and 24, as seen in FIG. 2. 
The integral spring, designated 62, is formed in the circular body 55 of 
the clip. The spring is in the form of a helix. The helix is formed by 
forming the blank illustrated in FIG. 5 into a cylinder about a vertical 
axis indicated at X. The bottom leg 64 of the blank, when shaped to form 
the cylindrical body 57, forms a rear split ring section providing the 
annular shoulder 56 that bears against the shoulder 46 in the contact 
passage. 
FIG. 2 shows how the integral spring portion 62 of the retention clip is 
axially compressed when the mating ferrules 32 and 32' abut upon 
engagement of the connector members, causing the ferrule 32 to slide 
rearwardly in the contact passage. Compression of the spring of the 
retention clip 54 produces a resilient force urging the ferrule 32 in the 
forward direction so that it will be maintained in firm abutting 
engagement with the mating ferrule 32' thereby providing a zero gap 
between the mating ferrules. 
FIGS. 6 and 8 illustrate alternative forms of a retention clip having an 
integral spring in its cylindrical body similar to that illustrated in 
FIGS. 3 and 4. The clip 154 shown in FIG. 6 is formed from the blank 163 
illustrated in FIG. 7. The clip 254 illustrated in FIG. 8 is formed from 
the blank 263 illustrated in FIG. 9. 
The contact retention clip 354 illustrated in FIG. 10 is somewhat different 
than the clips described previously herein in that the resilient spring 
portion 364 of the clip is embodied in the retention fingers 358, rather 
than in the circular body 355 of the clip. The clip 354 is formed from the 
blank 363 illustrated in FIG. 11. As seen in FIG. 10, the retention 
fingers 358 have a corrugated configuration, so that each finger has 
annular sections 358a, 358b and 358c, with each extending at an angle 
opposite to that of the next adjacent section. The forward ends 360 of the 
retention fingers extend longitudinally, and are adapted to engage behind 
the flange 50 on the ferrule 32. The contact retention fingers are 
released from behind the flange by the use of a conventional contact 
release tool that will engage the sections 358c of the fingers, causing 
the forward ends 360 to deflect outwardly. 
Preferably at least the two sections 358a and 358b of the retention fingers 
extend at an angle greater than 30.degree. relative to center axis of the 
retention clip 354 to assure that there will be significant axial 
compression of the fingers when the ferrule is pushed rearwardly in the 
contact passage in which the clip 354 is mounted. It should be noted here 
that in a typical contact retention clip such as shown in the McCartney 
patent or used in electrical connectors, the retention fingers extend at 
an angle of about 10.degree. to 20.degree. degrees relative to the center 
axis of the clip to assure that the fingers have a high columnar strength 
so that the fingers will not deform axially if a rearward force is applied 
to the contact mounted in the clip. Thus, there is virtually no resilience 
in the fingers in the axial direction nor is it intended. The retention 
fingers in a conventional clip are purposely designed to firmly retain a 
contact in a predetermined axial position, and are deflected only when 
engaged by a contact release tool, and then only in the radial direction 
to remove the fingers away from a rearwardly facing shoulder on the 
contact. 
Referring now to FIGS. 12 to 14 in detail, there is shown a fiber optic 
connector 70 comprising two mating halves 72 and 74 each containing a 
contact assembly 76, which can best be seen in FIG. 12. 
Each contact assembly 76 comprises a ferrule 78, an inner support tube 80 
and a contact retention clip, generally designated 82. The ferrule has a 
reduced diameter forward section 84 on which there is mounted an alignment 
sleeve 86. The open end of the sleeve slidably receives the forward end of 
the ferrule in the mating contact assembly 76 when the connector members 
72 and 74 are interengaged as seen in FIG. 14. 
The support tube 80 is retained in the ferrule 78 by matching inwardly 
extending annular ribs 88 and 90 formed in the walls of the support 80 
tube and ferrule 78, respectively. A second inwardly extending annular rib 
92 is formed at the forward end of the support tube 80. The ribs 88 and 92 
serve to closely support a fiber optic cable 94 extending into the rear of 
the contact assembly 76 so that the forward end of the cable will be held 
substantially on the center axis of the assembly whereby the bare optical 
fiber 96 of the cable 94 will not bend or droop within the ferrule. The 
end of the fiber 96 is centered in the forward end of the ferrule by a 
watch jewel 98. 
The rear of the ferrule 78 is formed with a generally L-shaped flange 100 
which fits over a flange 101 on the forward end of the forward portion of 
the retention clip 82. The flange 100, together with a second outwardly 
extending flange 102 on the rear of the support tube 80, serve to retain 
the retention clip 82 on the ferrule and support tube, but allows the 
support tube to slide rearwardly relative to the clip. 
The retention clip 82 has a forward generally circular body 104 and a rear 
retention element 106. The retention element comprises a first section 108 
which extends outwardly and rearwardly at a angle from the rear of the 
circular body 104 to an annular rib portion 110 that projects into an 
annular groove 112 formed in the wall of the contact passage 115. The 
retention element 106 also includes a second section 114 that extends 
downwardly and rearwardly from the rib portion 110 at an angle opposite to 
the angle of the first section 108. The retention element 106 is radially 
resilient so that when the contact assembly 76 is pushed into the passage 
114 the element 106 will deflect radially inwardly as it slides against 
the wall of the rear of the passage 114 until the rib portion 110 becomes 
aligned with the groove 112, whereupon the rib portion will snap out into 
the groove to retain the contact assembly in the passage. The retention 
element may be released from the groove 112 by inserting a tubular contact 
release tool (not shown) into either the front or rear end of the passage 
114, engaging respectively either the first section 108 or the second 
section 114 of the retention element causing the element to be resiliently 
deflected inwardly to thereby withdraw the rib portion 110 from the 
groove. 
As in the embodiments of the invention disclosed in FIGS. 1-10, the 
retention clip 82 illustrated in FIGS. 12-14 emboides an integral spring, 
which is shown as being in the form of a bellows 116 formed in the 
circular body 104 of the clip. The number of convolutions in the bellows 
is dependent upon the extent of force that is desired to hold the mating 
end faces of the ferrules in FIG. 14 engaged with each other. When the 
connector members 72 and 74 are engaged causing the ferrules to abut, the 
ferrule 78 of the contact assembly 76 in connector body 72 will be forced 
rearwardly, causing the support tube 80 to slide rearwardly relative to 
the retention clip 82 and the bellows to be compressed. This results in a 
positive abutment force being achieved at the mating interface of the 
ferrules. 
While the spring means embodied in the retention clip 82 is shown as being 
a bellows, it could also take the form of one of the spring arrangements 
in the retention clips illustrated in FIGS. 3-8. However, the retention 
clip 82 with integral bellows spring has the advantage that it can be 
manufactured relatively inexpensively by use of an eyeletting process, 
rather than requiring stamping and forming operations as are required for 
forming the retention clips illustrated in FIGS. 3-10. Further, the 
ferrule 78 in support tube 80 may also be formed by eyeletting processes 
so that entire contact assembly 76 may be manufactured at relatively low 
cost. 
The contact retention arrangement of the present invention also has utility 
in electrical connectors. An electrical connector would have essentially 
the same structure as the fiber optic connector illustrated in FIGS. 1 and 
2, except that hollow ferrule 32 would be a solid pin contact and the 
mating contact 32' would be a socket contact having an integral 
cylindrical forward end somewhat similar to the alignment sleeve 40 except 
that it incorporates a spring beam (not shown) assuring a resilient 
engagement between the pin and socket contacts. When the mating halves of 
an electrical connector engage, the pin contacts are supposed to slide 
into the socket contacts a predetermined axial distance to assure that 
there is an optimum electrical engagement between the contacts. However, 
this optimum engagement is not always achieved due to the buildup of axial 
manufacturing tolerances in the connector, which can result in either the 
mating pin or socket contacts, or both, shifting rearwardly in their 
respective contact cavities when the mating halves of the connector are 
engaged. By use of the contact retention clip of the present invention 
embodying an integral spring element, the spring will compress when the 
pin and socket contacts engage thereby accommodating to a significant 
degree the axial tolerance buildup, thus assuring an optimum electrical 
engagement between the mating contacts. Thus, each of the embodiments of 
the invention disclosed herein for a fiber optic connector may also apply 
to electrical connectors. 
Since the present invention is applicable to both fiber optic and 
electrical connectors, in the claims appended hereto, the term "contact 
element" has been used to embrace both a hollow fiber optic ferrule and an 
electrical socket contact or solid electrical pin contact. 
Although several embodiments of the invention have been disclosed herein 
for purposes of illustration, it will be understood that various changes 
can be made in the form, details, arrangement and proportions of the 
various parts in such embodiments without departing from the spirit and 
scope of the invention as defined by the appended claims.