FIELD OF THE INVENTION

The present invention relates to an optical connector assembly and a method for assembling a connector part of the optical connector assembly.

BACKGROUND OF THE INVENTION

From the prior art connector assemblies are known to interconnect optical fibers to each other.

US2014334783A was first published in July 201 3 in the name of Hewlett Packard Enterprise Development. It is directed to a connector module, which includes a module optical connector and an engagement member to engage with a device having a device optical connector. The engagement member upon engagement with the device is to cause movement of the module optical connector towards the device optical connector.

US2014219624A was first published in August 201 4 in the name of Xyratex Tech Ltd. The publication is directed to an optical connector for coupling with a comple mentary optical connector and for supporting an optical component. The con nector comprises a cover moveable between a first and second position. The cover may also comprise a moveable shield and biasing components. There is also pro vided an optical connector assembly comprising covers that seguentially open. A PCB comprising waveguides and an optical component sub-mount for integrating with the PCB is also presented. US5708745A was first published in May 1 996 in the name of Fujitsu Ltd. It is di rected to a device for preventing laser beam leakage, which excludes a danger that a laser beam emitted from a laser source directly attacks eyes of an operator when an external connector is connected to or disconnected from an internal connector. When the external connector has been removed from the optical transmission ap- paratus, a pair of movable shield plates are constantly urged in respective directions for closing a receiving opening of the apparatus to bring joining portions of the movable shield plates into close contact with each other. Thereby dust is prevented from entering the inside of the apparatus and the laser beam from being leaked. Furthermore, a limit switch is provided, which stops delivering an ON signal to an E/O laser module when the external connector is pulled out of the optical transmis sion apparatus. The E/O laser beam stops the supply of the laser beam, and thereby brings into effect a perfect measure for protection of the eyes of the operation from the laser beam.

US9207454B was first published in December 201 5 in the name of Cadence De- sign System Ing. It is directed to a system and a method for preventing contamina tion of an array of fiber optic connectors. The system includes a housing for retain ing the array of fiber optic connectors in an adjacent relation and an arrangement for delivering pressurized gas into said housing to prevent external contamination entering said housing and causing debris on a surface of one or more of the con nectors. A control arrangement is provided for deactivating the air flow after all optical connections are covered and protected from contamination. US2003221706 was first published in December 201 3 in the name of Amphenol

Corp. It is directed to a system to clean a set of optical connectors. The system in cludes a fluid source, a vacuum source, a support member, which defines a clean ing device edge, and a set of cleaning devices. Each cleaning device includes a fluid intake member, which connects to the fluid source, a fluid output member, which connects to the vacuum source, and a cleaning head, which connects to the fluid intake member and the fluid output member. A set of cleaning devices is configured to align over a set of optical interfaces of the set of optical connectors, direct fluid from the fluid source toward the set of optical interfaces, and draw the directed fluid away from the set of optical interfaces and toward the vacuum source. US2002102065 was first published in August 2002 in the name of Amphenol

Corp. It is directed to technigues for cleaning an optical interface pneumatically, i.e., using fluid, such as liguid or gas. Fluid can be delivered in an automated manner at a particular time (e.g., connection time) in order alleviate the burden of a technician having to manually clean the optical interface with conventional cleaning material or a stick-on adhesive each time the technician exposes the optical interface. US201 3330957 was first published in December 201 3 in the name of Tyco Elec tronics Crop. It is directed to a connector assembly including an outer housing hav ing a front end, a back end, and a central axis extending there between. The outer housing has a passage that extends there through. The connector assembly also includes a slidable connector that is disposed within the passage. The slidable con nector includes a communication module. The connector assembly also includes a spring frame that is positioned between the slidable connector and the outer hous ing. Prior to mating with a mating connector, the spring frame mechanically cou ples the slidable connector with respect to the outer housing. After the mating con- nector and the communication module are communicatively coupled, the spring frame releases the slidable connector from the outer housing such that the slidable connector is permitted to move relative to the outer housing. The spring frame me chanically couples the slidable connector relative to the mating connector.

From the prior art, optical connector assemblies are known which comprise a first connector part and a second connector part suitable to be mated to each other. In some applications, at least one of the connector parts is placed on a circuit board to further process the optical signal. A ferrule, terminating at least one optical fiber of at least one connector part is mounted displaceable in a spring-loaded manner such that a contact pressure between both ferrules of the respective connector parts is maintained in a mated state. In most applications, the spring is designed as a spiral spring arranged co-axially around the optical fiber(s) and inside a housing of the respective connector part. The spring is therefore usually mounted behind the ferrule around the optical fiber(s) and inside the connector housing. Screws and e.g. a support plate are known means to secure and brace the spring to the housing.

Due to the complicated built-up and the amount of components connector parts known form the prior art are comparatively expensive. Furthermore, the assembly of the individual connector parts (such as fasting the ferrule and the spring to the connector housing) is often difficult and time-consuming. This is especially the case, if the spring needs to be exchanged when compatibility problems between the spring's dimensional tolerances and/or spring's force and the respective connector parts occur. Especially the assembly of individual connector parts where the housing is already fastened on a line card or circuit board is unfavorable due to the restricted available space on such boards, where the connector part is among others surrounded by multiple components.

SUMMARY OF THE INVENTION It is an object of the invention to provide an optical connector assembly having con nector parts that are easier to assemble and to operate.

An optical connector assembly according to the invention comprises a first con nector part and a second connector part suitable to be interconnected to the first connector part in a mating direction. The first connector part comprises a housing having an opening extending in the mating direction through the housing from a front end to a rear end of the first connector part. The front end is the end of the connector part, which is in the mated state directed towards the second connector part. The rear end is usually the end of the first connector part from where the fer- rule is inserted. The first connector part further comprises a ferrule assembly ar ranged in a mounted position of the first connector part in the opening, displacea ble in the mating direction with respect to the housing. The ferrule assembly com prises a ferrule terminating at least one optical fibre. During mating with the second connector part, the ferrule assembly is displaced with respect to the housing to- wards the rear end of the first connector part against the force of a spring of a spring assembly interconnecting the housing and the ferrule assembly. In a braced state of the spring assembly, the ferrule assembly arranged in the opening of the housing is pressed by the at least one spring against the housing. Thus, the move ment of the ferrule assembly is on one hand restricted in the mating direction to- wards the front end of the first connector part and, on the other hand, the ferrule assembly is mounted spring-loaded in the mating direction towards the rear end of the connector part. The housing and the ferrule assembly may comprise connecting means to attach or to secure the spring assembly with respect to the housing or another element. In comparison to connector parts known from the prior art, the spring assembly according to the invention is easily accessible from the outside of the first connector part, i.e. without complicated disassembly. Preferably, the spring assembly is ar ranged on the outside of and adjacent to the housing e.g. extending at least partly along an outer face of the housing. The spring assembly comprises at least one spring. The spring assembly may further comprise other parts to transmit the force of the spring and/or to support the same. The at least one spring may be a spiral spring and/or a leg-spring and/or a leaf spring. In a variation the spring assembly is arranged laterally offset with respect to the ferrule assembly respectively the gen eral extension of the optical cable interconnected to the ferrule assembly to avoid certain problems known from the prior art.

Good results can be achieved, if the spring assembly is based on one or more leg- springs that provides good clearance and easy accessibility from the outside as fur- ther described herein after. The leg-spring comprises a first leg, a second leg and a there between arranged coiled section interconnecting the first leg and the second leg. The leg spring is foreseen to exert a restoring force between the ferrule assem bly and the housing, when the ferrule assembly is displaced with respect to the housing in the rearward direction. The first leg is normally used to interconnect to the housing and the second leg is normally used to interconnect to the ferrule as sembly or vice versa. For an even force balance on the ferrule, the spring assembly may comprise two leg-springs interconnected to each other via a bracket. The two legs of the different leg-springs may also merge continuously into each other form- ing said bracket. End sections of the first and/or second legs may point towards each other. In case that the spring assembly comprises more than one coiled section, the coiled sections are preferably arranged coaxially but spaced a distance apart with respect to each other. Depending on the application, the ferrule assembly may comprise a ferrule plunger guided in the opening of the housing, displaceable in the mating direction. The fer rule plunger serves to transmit the force of the spring on the ferrule. Advanta geously, the ferrule plunger is arranged with respect to the mating direction behind the ferrule (in mating direction at the rear end of the first connector part) and com prises connecting means to interconnect to the spring assembly. The connecting means of the ferrule plunger may e.g. be at least one recess in which a section of the spring, such as the end sections of the first and second legs or, if present, the bracket, may be inserted and secured. If appropriate, the ferrule assembly may comprise a pin holder to hold and align guiding pins of the ferrule. The guiding pins may extend in the mounted position through and out of a front end of the ferrule to interconnect the same to a corresponding ferrule of the second connector part. If a ferrule plunger is present, the pin holder is arranged between the ferrule plunger and the ferrule. Alternatively, the guiding pins may also be located in the ferrule of the second connector part, meanwhile the ferrule of the first connector part features corresponding guiding holes. The pin holder and the ferrule plunger may further be formed as a single integral part, incorporating the different func tions of both parts.

For assembly of a preferred variation of a first connector part, the following method steps are usually performed: Providing a housing comprising an opening extending in a mating direction through the housing from the front end to the rear end of the housing. Providing a ferrule assembly comprising a ferrule terminating at least one optical fibre. Providing a spring assembly comprising at least one spring. These steps are followed by inserting the ferrule assembly into the opening of the housing and subseguently interconnecting the spring assembly to the housing and to the ferrule assembly from the outside such that the ferrule assembly is displaceable against the force of the spring.

5 For a fast and easy interconnection of the spring assembly to the housing, the first connector part, as described above, may comprise a tension member to mount and tension the spring of the spring assembly between the ferrule assembly and the housing during mounting of the spring assembly. Therefore, the tension member comprises a retaining means to engage a section of the spring assembly during as-o sembly. In a preferred variation, the retaining means is a recess or a hook or the like in which the respective spring section may initially be linked in a less or non-ten- sioned state of the spring. For the mounting of the spring, the tension member, respectively the retaining means with the thereto-liked spring may then be dis placed or pivoted about an axis with respect to the housing respectively the ferrule5 assembly such that the spring is braced during the displacement in a controlled manner. In a preferred variation, the housing comprises a recess to accommodate and secure the tension member in the braced state of the spring. Preferably, the recess is arranged symmetrically to the ferrule assembly on an outer face of the housing such as e.g. the top face. Depending on the application, the first connector0 part may be suitable to be interconnected to a circuit board, in particular a line card.

Therefore, the first connector part may comprise fastening means for interconnect- ing the first connector part to said board or card. Furthermore, the second con nector part may be suitable to be interconnected to a circuit board, such as e.g. a backplane.

It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an over view or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illus trate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The herein described invention will be more fully understood from the detailed de scription given herein below and the accompanying drawings, which should not be considered limiting to the invention described in the appended claims. The draw- ings are showing:

Fig. 1 A first variation of a first connector part according to the invention in a perspective and partly sectionized view from a front end;

Fig. 2 the first connector part according to Figure 1 in a perspective and partly sectionized view from a rear end; Fig. 3 a second variation of the first connector part according to the invention during assembly in a perspective view from the rear end;

Fig. 4 the first connector part according to Figure 3 during assembly in a per spective view from the rear end; Fig. 5 the first connector part according to Figure 3 in an assembled state in a perspective view from the rear end after assembly;

Fig. 6 the first connector part according to Figure 3 to 5 in an exploded view from the front end;

Fig. 7 the first connector part according to Figure 5 in a view on the top face; Fig. 8 the first connector part in a sectionized view (A-A) according to Figure

7;

Fig. 9 an optical connector assembly according to the invention in a perspec tive view.

DESCRIPTION OF THE EMBODIMENTS Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many dif ferent forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

Figure 1 and Figure 2 illustrate a first variation of a first connector part 2 according to the invention in a perspective and partly sectionized view, meanwhile Figure 4 to Figure 8 show a second variation of the first connector part 1 according to the invention. The second variation differs from the first variation in the presence of a tension member 21 , as explained in more detail below. Figure 9 shows an optical connector assembly 1 according to the invention in a perspective view having a first connector part 2 and a second connector part 3.

Figure 1 illustrates a first variation of a first connector part 2 in a perspective and partly sectionized view from a front end 24 and Figure 2 from a rear end 25. The front end 24 is the end of the first connector part 2 suitable to be interconnected to a second connector part 3 to form a connector assembly 1 (compare Figure 9). The shown first connector part 2 is fastened by fastening means 20 (not shown) to a line card or /circuit board 4 and comprises a housing 5 with an opening 6 ex tending in the mating direction (x) through the housing 5 from the front end 24 to the rear end 25 (compare Figure 6). A ferrule assembly 7 is arranged in the open- ing 6 in the shown assembled state of the first connector part 2. The ferrule assem bly 7, which can only partly be seen in Figure 1 and Figure 2, comprises a ferrule 8 terminating at least one optical fiber 9. The ferrule 8 is arranged in the mating directing (x) in the opening 6 at the front end 24 of the first connector part 2. A pin holder 1 7 and a ferrule plunger 1 9 are arranged in the opening 6 behind the ferrule 8 in direction of the rear end 25. The pin holder 1 7 is hereby located be tween the ferrule 8 and the ferrule plunger 1 9. The pin holder 1 7 holds and aligns the guiding pins 1 8 of the ferrule 8. If no guiding pins 1 8 are present on the first connector part 2, the pin holder 1 7 may be left out such that the ferule plunger 1 9 abuts directly to the ferrule 8. The set-up of the ferrule assembly 7 according to the first variation is identical to the ferrule assembly 7 according to the second variation of the first connector part 2 and can be seen in more detail in Figure 6, described hereinafter in more detail. As seen in Figure 1 and Figure 2, the first connector part 1 further comprises a spring assembly 1 0 comprising at least one spring 1 1 . The spring assembly 1 0 is arranged accessible from the outside of the first con nector part 2, respectively the housing 5 and is further arranged with a lateral offset with respect to the ferrule assembly 7. In the shown first and second variation of the first connector part 2, the spring assembly 1 0 comprises two leg-springs 1 1 . One leg-spring 1 1 comprises a coiled sections 1 6 and two therefrom extending legs (first and second legs) 1 3, 1 4. The first leg 1 3 is suitable to be interconnected to the housing 5 and a second leg 1 4 is suitable to be interconnected to the ferrule assembly 7. In the shown case, the first legs 1 3 are interconnected by a bracket section 1 5 wherein end sections 35 of the second legs 1 4 are pointing towards each other. It can be seen that the two coiled sections 1 6 of the respective inter connected leg-springs 1 1 are arranged coaxially with respect to each other and are both arranged at the rear end 25 of the first connector part 2.

The spring assembly 1 0 interconnects the housing 5 and the ferrule assembly 7. During mating with the second connector part 3 (not shown here, compare Figure 9) the ferrule assembly 7 may thus be displaced with respect to the housing 5 against the force of a spring 1 1 of the spring assembly 1 0. For the attachment of the spring assembly 1 0 to the housing 5 and the ferrule assembly 7, the housing 5 and the ferrule assembly 7 comprise connecting means 1 2, 33. In the shown vari- ation, the connecting means 33 are arranged on the ferrule plunger 1 9, which serves to transfer the spring force on the ferrule 8 in mating direction towards the front end 24 of the first connector part 2.

Figure 3 to Figure 8 illustrate the second variation of the first connector part 2. The shown first connector part 2 only differs from the first connector part 2 of the first variation in that the shown first connector part 2 additionally features a tension member 21 arranged on a top face 26 of the housing 5. The tension member 21 serves to tension the spring(s) 1 1 of the spring assembly 1 0 between the ferrule assembly 7 and the housing 5, during mounting of the spring assembly 1 0. Figure 3 to Figure 5 illustrate the mounting process of the spring assembly 1 0. From a completely disassembled state as illustrated in the exploded view of Figure 6, the ferrule 8 is interconnected to the guiding pins 1 8 and the pin holder 1 7. The guiding pins 1 8 extend in the assembled state through the ferrule 8. Circumferential grooves 32 are arranged at each rear end of the guiding pins 1 8 to interconnect the guiding pins to the pin holder 1 7. The guiding pins 1 8, respectively the grooves 32 are inserted in designated cutouts 3 1 of the pin-holder 1 7. The guiding pins 1 8 may further be glued or attached by other means to the ferrule 8. The assembled pin holder 1 7, the ferrule 8 and the guiding pins 1 8 are then inserted together with the ferrule plunger 1 8 into the opening 6 of the housing 5 from a rear end 25. The spring assembly 1 0 can be interconnected to the ferrule plunger 1 8 before or after inserting the ferrule assembly 7 into the housing 5. In the shown case, the inter- connection is realized by inserting the second legs 1 4 - which point toward each other - into the connection means 33 (respectively the recesses 33 arranged on opposite sides of the ferrule plunger 1 8). When the ferrule assembly 7 is at least partly inserted in the opening 6 of the housing 5, the spring assembly 1 0 can then be liked into a retaining means 23 of the tension member 21 being in an open po- sition to engage the at least one spring 1 1 (compare Figure 3). By displacing the tension member 21 , respectively the retaining means 23 with the interconnected spring assembly 1 0, the ferrule assembly 7 is further inserted in the opening 6 and the at least one spring is braced (compare Figure 4) . Preferably, the tension mem ber 21 is pivoted in order to displace the retaining means 23 with the thereto-linked spring assembly 1 0. In the shown variation this is realized by a pivot pin 22 of the tension member 21 arranged pivotable in the housing 5. The retaining means 23 thus guides the interconnected section 1 5 of the spring assembly 1 0 to the con nection means 1 2 arranged in the housing 5. The connection means 1 2 of the housing 5 is in the shown case a shoulder 1 2, respectively a recess, behind which, or in which, the section 1 5 of the spring assembly 1 0 is fixated in the assembled state of the first connector part 2. Figure 5 and Figure 8 illustrate said assembled state. Figure 8 shows a sectionized view (according to Figure 7) of the first con- nector part 2, illustrating the inner built-up of the same. In the assembled state, the tension member 21 is at least partially accommodated in a respective recess 34 of the housing on a top face 26 of the housing 5. However, in other embodiments the recess 34 may also be placed on a side face 27 of the first connector part 2. Fur thermore, the ferrule 8 comprises a shoulder 28, which is pressed by the springs 1 1 , 1 1 against a corresponding shoulder 29 arranged in the opening 6 of the hous ing 5, when the first connector part 2 is not mated to the second connector part 3. In a mated state, the interconnection force 36 by the second connector part 3 (not shown) presses the ferrule assembly 7 rearwards against the force of the spring (as it can be seen in Figure 8) and by doing so, a sufficient contact pressure is provided during mating. The spring force is thus transferred from the spring assembly 1 0 to the ferrule plunger 1 9, to the pin holder 1 7 and further to the ferrule 8.

Figure 9 illustrates an optical connector assembly 1 comprising a first connector part 2 (according to the second variation) and a second connector part 3. For the mating of the two connector parts 2, 3, the first and second connector part 2, 3 comprise alignment means 30 to align both parts during a first phase of the mating. In the shown variation, the second connector part 3 therefore features two align- ment pins 30, which during interconnection are inserted in alignment means, re spectively alignment openings 30 of the first connector part 2 for the alignment pins. Furthermore, it can be seen that the ferrule 8 of the second connector part 3 features guiding openings for the guiding pins 1 8 of the ferrule 8 of the first con- 5 nector part 2. It is clear, that the guiding pins 1 8 and the respective openings as well as the alignment pins and/or the respective openings 30 can be placed either on the first or on the second connector part 2, 3. Furthermore, the housings 5 of the first and second connector parts 2, 3 may be formed such that in a mated state both housings 5 at least partially engage with each other. The illustrated secondo connector part 3 may equally be used to interconnect the first connector part 2 according to the first variation, as shown in Figure 1 and Figure 2.

Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without depart ing from the spirit and scope of the invention. 5

LIST OF DESIGNATIONS

1 Optical connector assem 20 Fastening means

bly 21 Tension member

2 First connector part 22 Pivot pin(tension member)

3 Second connector part 23 Retaining means (tension

4 Line card / board member)

5 Housing 24 Front end

6 Opening 25 Rear end

7 Ferrule assembly 26 Top face

8 Ferrule 27 Side face

9 Optical fiber 28 Shoulder (ferrule)

1 0 Spring Assembly 29 Shoulder (housing)

1 1 Leg-spring 30 Alignment means (hous

1 2 connecting means ing)

1 3 First leg 3 1 Cutouts (pin holder)

1 4 Second leg 32 Groove (pin)

1 5 Bracket 33 Connecting means (ferrule

1 6 Coiled section plunger)

1 7 Pin holder 34 Recess (housing)

1 8 Guiding pins 35 End section (spring)

1 9 Ferrule plunger 36 Interconnection force