Patent Document

FIELD OF THE INVENTION 
     This invention relates to optical connector adapters for use in optical fiber transmission and, more particularly, to an adapter for creating an electrical indication of the condition of the connector and for locking the connection during signal transmission. 
     BACKGROUND OF THE INVENTION 
     Optical fiber transmission systems are becoming widely used in the transmission of signals such as data, voice, and the like, and in many instances, are replacing traditional electrical systems. Many of the arrangements common to electrical systems, such as coupling, interconnection, splicing, and the like have their counterparts in optical systems but, because of the totally different characteristics of the transmission media, i.e., optical fiber versus metallic wire, connectorization, splicing, and the like involve quite a different apparatus. Where, for example, it is necessary to make a great number of connections in one location, both systems may use what is referred to in the art as patch panels, which provide arrays of connector adapters for interconnection, but the interconnections themselves are generally quite different. 
     It is common practice in the optical connector art to terminate a length of optical fiber with a connector, an example of which is the SC type connector that is shown and described in U.S. Pat. No. 5,212,752 of Stephenson et al. There are numerous types of such fiber terminating connectors, and, inasmuch as there has been little effort directed to standardization, each type of connector generally requires a different coupling arrangement to permit interconnection of two fibers, for example. 
     When large numbers of such interconnections are to be made, it is common practice to use patch panels for holding an array of a large number of coupler adapters. Thus, there literally can be hundreds of such adapters, all in close proximity to each other, mounted in the panel. As long as only a single type of connector, such as the SC connector, is involved, simple adapters may be used for plugging in the connectors from each side of the patch panel. In view of the fact that there are several different types of connectors in widespread use today, it has become common practice to replace the simple adapters with buildout blocks or buildout coupling adapters. In U.S. Pat. No. 5,274,729 of King et al., there is shown a buildout coupling adapter system in a patch panel that makes possible interconnections among the several different types of connectors in any combination thereof. As can be seen in that patent, a buildout block at one side (or end) thereof is configured the same as a simple coupler adapter having a keyway for receiving, for example, an SC connector. The other end of the buildout block is formed to receive a buildout which may be configured to receive and hold, for example, an SC, an ST, an LC, or an FCMV connector. Thus, the patch panel may be, on the one side thereof, pre-connectorized with optical fibers all of which are terminated by, for example, SC connectors, and the other side of the panel is ready to receive pre-connectorized fibers terminated by any one of the numerous connectors. Such an arrangement is more versatile and adaptable than those arrangements which are limited to a single type of pre-connectorized fiber. Such an arrangement also functions well in those installations where one side of the panel is not readily accessible. Thus, before being mounted in position, the panel can be pre-connectorized on the side which will be relatively inaccessible, after which it can be mounted in place, ready to receive the numerous connections thereto, regardless of connector type. In order to pre-connectorize the panel, the adapters are usually made of two parts, a base member (buildout block) that attaches to the panel and a cap member (buildout) which receives the connector plug, and which is insertable into the base member. Such a two part adapter is commonly referred to as a split adapter. One particular advantage of a split adapter, in addition to the build-out feature, is that access to the ferrule distal or butting ends for cleaning (or repair) obtains when the cap and base are separated. 
     In any such arrangement there is a potential safety hazard that is often present. Where one or more of the pre-connectorized fibers is carrying optical energy, such energy can be emitted from the end of the fiber connector and pass through the unoccupied buildout block or coupling adapter to the side of the panel where connections are to be made. This optical energy can be harmful for the operator or installer and can be especially harmful to his or her eyes. This hazard is most prevalent when an active connection has to be repaired, cleaned or otherwise altered by removal of an existing connectorized fiber and replacement with another. In such an instance, it might be difficult or otherwise impractical to shut off the signal transmission in that particular fiber circuit, hence, the installer is forced to deal with a light emitting junction or connection. 
     This hazard has long been recognized and there are numerous arrangements in the prior art for blocking any light emanating from a fiber connection through an open adapter. In U.S. Pat. No. 5,678,268 of Stephenson et al., there is shown a pivotable optical shutter arrangement wherein a normally closed pivotable shutter blocks the open exit of an adapter when a connector plug is removed. The shutter advantageously requires only one motion to open it to permit insertion of a plug or connector into the adapter. Such a shutter as shown in the patent is operable by only one hand instead of prior art arrangements which generally require awkward use of two hands by the installer. One of the disadvantages of any shutter arrangement however, is that they are easily “defeatable” in that they can be, during installation of large numbers of connectors and in the interest of expedition, for example, temporarily fixed in the open position, thus contravening their purpose. In addition, the fiber optical transmission art has progressed to the use of higher and higher light energy or power, and has reached a point where shutter arrangements in general have, because of the large light energy, become transparent to much of the energy in the form of infra-red light, which is commonly used. Additionally, when the light intensity is very high, actual damage to the optical connector and the associated fibers can occur. 
     There are many arrangements in the prior art aimed primarily at reducing the possibility of injuring the operator, such as are shown in U.S. patent application Ser. No. 09/748,906, filed Dec. 27, 2000 of Norman R. Lampert et al. and Ser. No. 09/784,574, filed Feb. 15, 2001 of Norman. R. Lampert et al. In the Lampert et al. arrangement, insertion of the connector plug into the adapter creates a signal, such as by activating a switch, which generates an indication that the connection is completed and signals may be transmitted through the connection. Withdrawal of the connector plug from the adapter deactivates the switch or other signal generator, indicating that the adapter is not to be used in transmitting optical signals. 
     With the increasing use of high power signal transmission, it is important that the butting ends of the connector ferrules within the adapter not be separated while high power light is being transmitted therethrough. Such a separation can, in the high power use, cause severe damage to the distal (or butting) ends of the ferrules. This is especially important with split adapters in a build out arrangement, inasmuch as different types of connector plugs may be used, hence generation of a signal for signaling that the signal transmission should be turned off or on should not depend upon especially designed or otherwise modified plugs. Thus any safety arrangement should, preferably, be contained within the split adapter. Further in the interests of safety, it is preferable that an operator or installer should have to take positive action to prepare the connection for signal transmission, or to disconnect the connection. In the prior art, such as in the aforementioned Lampert et al. arrangements, the operation does not require the operator or installer to take any positive action other than inserting the connector plug into the adapter or withdrawing it therefrom. It is, therefore, desirable that the operator be able to cut off the transmission through the connector prior to separation of the butting ends of the connector plug ferrules, and to delay optical transmission until the plug is fully inserted in the adapter. 
     SUMMARY OF THE INVENTION 
     The invention as disclosed herein is directed primarily to its application in a split adapter. However, the principles of the invention are readily adaptable for use in a unitary adapter. 
     The present invention, in a first embodiment thereof, is a split adapter comprising a base member for mounting to a panel, for example, and a cap member insertable therein. The cap member has first and second side latching members and a top latching arm which mate with corresponding latch receivers in the base to lock the cap in place in the base. The cap maybe removed from the base by depressing the latching arm and exerting a pulling force (such as one-half to one pound) on the cap to disengage the side latches. The side latches have enlarged portions at this distal ends, which are angled, as will be disclosed hereinafter, to function as latches but which are defeatable by the pulling force. As will be more clearly apparent hereinafter, when a connector plug is inserted into the cap, it serves to hold the side latches in place so that the cap is firmly attached to the base and separation effectively prevented. 
     In accordance with the invention, the base member has a switch mounted therein and the cap member has a switch actuation lever slidably mounted therein. Many forms of actuation lever can be substituted, such as a rotatable or pivoted actuation lever. The lever has a flexible portion which permits it to be moved out of the way for insertion of the connector plug into the cap. After the plug is inserted, the lever is slid forward by the installer or operator to where it actuates the switch, which is preferably of the plunger type, and, at the same time latches into place in the forward position. In this position, a projection on the lever bears against the underside of the top latching arm, preventing its being depressed, thereby further insuring that the cap and base are firmly locked together. The lever has an enlarged end portion which overlies and masks the latching arms of the connector plug, thereby preventing removal of the plug when the lever is in the forward position. Furthermore, in the forward or switch actuating position of the lever, the enlarged end, which masks the latching arm of the connector plug, cannot be bent out of the way, thereby insuring that the connector plug cannot be disconnected. The net result is that the cap is affixed to the base and the plug is affixed to the cap, thereby insuring against accidental or unintentional separation of the components. The actuated switch can close an electrical circuit which, for example, may directly halt signal transmission through the connector, or which may generate a signal informing an operator or monitor to halt the signal transmission. It is, of course, preferable that the circuit cut off transmission, such as by turning of the power laser, without human intervention. 
     When a disconnect is desired, the actuation lever must be pulled back to provide access to the plug latching arm, thereby halting the signal transmission by opening the switch. It is only after this first step that the enlarged end portion may be bent out of its masking position to give the operator or installer access to the connector plug for removal thereof. 
     It can be seen, and further will be more readily apparent, that when a connector plug is not in the cap, there is no signal transmission. Further, in order for signal transmission to commence, the operator must first insert the connector plug and then slide the actuation lever forward to its latched position wherein the switch is actuated to permit signal transmission and the connection cannot be broken, as by separation of the parts, thereby insuring protection of the ferrules and of any personnel in the vicinity. 
     In a second embodiment of the invention, the top latching arm on the cap may be eliminated in the interest of creating a smaller footprint, and the side latches relied upon to hold the cap and base together. 
     While the principles of the invention are shown and described as embodied in a split adapter comprising a base and a cap, the adapter may be a unitary housing in which the operative feature and components of the invention are included. 
     These and other features of the present invention will be more readily apparent from the following detailed description, read in conjunction with the following drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded isometric view of the adapter of the invention; 
     FIG. 2 a  is a front isometric view of the base member of the adapter; 
     FIG. 2 b  is a rear isometric view of the base member of FIG. 2 a;    
     FIG. 3 a  is a rear isometric view of the cap member of the adapter; 
     FIG. 3 b  is a front isometric view of the cap of FIG. 3 a;    
     FIGS. 3 c - 3   e  are detail views of the latching arrangement for joining the cap member to the base member; 
     FIG. 4 a  is a front isometric view of the actuation lever of the adapter; 
     FIG. 4 b  is a rear isometric view of the actuation lever of FIG. 4 a;    
     FIG. 5 is a side isometric view of the cap member of the adapter of the invention in partial cross section; 
     FIG. 6 is an isometric view of the adapter of the invention in its passive, or Power Off, configuration; 
     FIG. 7 is a side elevation view of the adapter of the invention in its active, or Power On, configuration; and 
     FIG. 8 is a cross sectional isometric view of the adapter of the invention in the configuration of FIG.  6 . 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 is an exploded isometric view of the split adapter assembly  11  of the present invention. Assembly  11  comprises a base member  12  and a cap member  13  which is adapted to be affixed to the base member  12  by means of resilient latching arms  14  (only one of which is shown), the enlarged ends  16  of which engage latching ports  17  in base  12 . Base member  12  is adapted to be affixed to a panel (not shown) for example, by means of latching arms  18  and shoulders  19 . As is common prior art practice, base  12  and cap  13  are made of suitable plastic material. 
     A switch assembly  21  is mounted by suitable means in the rear end  22  of base  12  and held in place by latching arms  20  on base  12 . Assembly  21  comprises, preferably, a plunger type switch  23  having an actuating plunger  24 , which is mounted on a support member  26 . A pair of leads  27  and  28  extend from the assembly  21  for transmitting a signal (open/close) from the switch  23  to control circuitry, not shown, for activating a light source or signal (switch closed) or de-activating it (switch open). The terms front, rear, top, bottom, and sides are used to designate elements as shown in the drawings and are not meant to be restrictive as to orientation of the elements in use. Base  12  further comprises a substantially hollow housing  29  having an opening  31  in the front end  32  thereof for receiving cap member  13 . To this end, a pair of rails  33 ,  34  extend from the front end  32  into the interior of housing  29  for supporting and aligning cap member  13 . 
     Cap member  13  comprises a substantially hollow housing or body member  36  having a sled member  37  extending from the front end  38  thereof which is adapted to ride upon the rails  33  and  34  in base  12  for supporting the cap  13 . A connector ferrule alignment sleeve  39  also extends from front end  38 , for containing the ferrule of a connector plug (not shown) which is introduced into cap  13  through an opening  40 . A latching member or arm  41  projects from the top  42  of cap  13  and extends toward the rear  43  thereof, to a distal end  45 . Arm  41  has a latching lug  44  at its front end which is adapted to mate with a shoulder  46  at the top of opening  31  in base  12 . This latching arrangement is more clearly shown in subsequent figures. 
     Extending from the rear of cap  12 , at the top thereof, toward the front  38  is a slot  47  having overhangs  48  and  49  at the top thereof for receiving an actuation lever  51  which is longitudinally slideable in the slot  47  and prevented from moving vertically by overhangs  48  and  49 . Lever  51  has a front portion  52  and a rear portion  53 , separated by a flexible web  54 . Extending from the front portion  52  is a latching arm  56  and first and second side latching arms  57  and  58 . The functions of these latching arms  56 ,  57 , and  58  will be explained and discussed hereinafter. Extending upward from the top surface of portion  52  is a projection or post  59  which will likewise be discussed hereinafter. The rear portion  53  of lever  51  has an enlarged portion  61  at its end which has a stiffening rib  62  extending therefrom, as shown, and which is shaped in a manner to be discussed hereinafter. 
     FIGS. 2 a  and  2   b  are front and rear views respectively of base member  12  with the switch assembly  21  mounted thereon and with a connecting plug  63  inserted in the opening in rear end  22 . Plug  63  may be, as discussed in the foregoing, an SC type connector plug or any of other types of standard plugs. In a panel arrangement it is common practice to have all of the plugs  63  inserted in the bases  12  to be of the same type. Switch assembly  21  is held in place by anchoring arms  20 , but it is to be understood that any suitable mounting for switch assembly  21  may be used with the switch actuator or plunger  24  facing toward the interior of housing  29 . As discussed before, switch  23  is shown as a plunger type switch, however, any of a number of switch types may be used, such as, for example, a leaf switch or a Hall effect switch. 
     FIGS. 3 a  and  3   b  are rear and front views, respectively, of the cap  13  of the invention, as discussed with regard to FIG.  1 . Opening  40  in the rear end  43  of cap body  36  receives a connector plug which, when inserted latches in the body  36  is a manner known and used in the prior art depending upon the type of connector plug used. As will be apparent hereinafter, the ferrule of the connector plug fits into alignment sleeve  39 , as does the ferrule of connector  63  so that the ferrules are aligned and abut each other unless they are intentionally separated by, for example, an impedance or other device, such as a disk. The front end of slot  47  forms a latching shoulder  68 , the purpose of which is explained hereinafter. 
     FIGS. 3 c  through  3   d  are partial detail views of the operation of the latching arm  14 ,. enlarged portion  16  at the distal end of arm  14 , and different configurations for latching port  17 . In FIG. 3 c  it can be seen that enlarged portion  16  has a triangular shape, having a sloped front face  15  and a sloped rear face  15 ′. When the enlarged portion  16  is within port  17 , cap member  13  is lightly latched to base  12 , but, as pointed out hereinbefore, it can be easily removed with a one-half to one pound pull because of the slope of face  15 ′ and the resilience of arm  14 . However, when a connector plug  77  (see FIG. 7) shown in dashed lines in FIG. 3 c , is inserted into cap  13 , it bears against the inner surface of arm  14  and thereby prevents the portion  16  from being disconnected from port  17 , thereby latching cap  13  firmly to base  12 . The inner surface of arm  14  may have a raised portion  25  to ensure that the plug forces portion  16  into port  17  and prevents its removal. In FIG. 3 d , port  17  is shown with an angled wall  17 ′ engaged by said portion  16  to facilitate removal of cap  13  from base  12 , and FIG. 3 e  shows enlarged portion  16  without rear face  15 ′, but port  17  with the angled wall  17 ′. In all three cases, the angular relationship of the engagement of the enlarged portion  16  and port  17  maintains cap  13  and base  12  lightly latched together to prevent accidental separation, and yet facilitates separation when desired by a one-half to one pound pull on cap  13 . However, when a connector plug is inserted into cap  13 , the angular relationship is defeated and base  12  and cap  13  are firmly latched together. 
     FIGS. 4 a  and  4   b  are, respectively, front and rear isometric views of the actuation lever  51 . As can be seen, lever  51  comprises front portion  52  and rear portion  53  separated and joined by a flexible web  54 . Front portion  52  comprises an elongated latching arm  56  having a latch projection  69  which is adapted to mate with latching shoulder  68  when lever  51  is located in slot  47  in its rearward position. The latching action between shoulder  68  and projection  69  prevents lever  51  from slipping out of slot  47 , yet can be overcome upon the application of sufficient pulling force (1-2 pounds) for removal of the lever. The nose end  71  of arm  56  is the switch actuating end which, as will be apparent hereinafter, actuates the switch  23  by depressing plunger  24  when the lever is advanced to its forward position, which is shown in FIG.  5 . In order that lever  51  be held in the forward or actuating position, front portion  52  thereof has first and second resilient latching arms  57  and  58  having, respectively, latch projections  72  and  73  which mate with latch projections  74  and  76  on either side of the slot  47 , as seen in FIG.  5 . When lever  51  is pushed forward, arms  57  and  58  are cammed inward as projections  72  and  73  pass over projections  74  and  76  and then snap outward as projections  72  and  73  latch to projections  74  and  76 . As is the case with latch  68  and  69 , the latching action is sufficient to prevent lever  51  from being pulled out of its forward position, but can be defeated by a one to two pound pull to the rear on lever  51  when removal thereof is desired. In the forward position as seen in FIG. 5, web  54  is well within slot  47 , and, as a consequence, rear portion  53  cannot be bent upward, as shown in FIGS. 4 a  and  4   b , being prevented therefrom by overhangs  48  and  49 . 
     The assembled adapter  11  in its non-actuating configuration, with a connector plug therein, is shown in FIG. 6, and FIG. 7 depicts the adapter  11  in its operating (actuated) configuration with a connector plug  77  inserted therein. For illustrative purposes, an LC connector plug is shown, however, as pointed out hereinbefore, plug  77  may be any one of a number of different plug types well known in the art. In FIG. 6, actuation lever  51  is in its rearmost position and although not shown, arm  56  thereon is latched to shoulder  68  at the end of slot  47 . The rear portion  53  of lever  51  is shown bent upward so that enlarged portion  61  clears opening  40  for insertion of connector plug  77  therein. Latching arms  14  are latched to ports  17  and latching arm  41  is latched to shoulder  46 , to the interior side thereof, in base member  12 . Upon insertion of plug  77  into opening  40  to where its latching arm  78  is engaged in cap  13 , in the manner well known in the art, the body  79  of plug  77  bears against the inner surfaces of latching arms  14  thereby preventing their disengagement from ports  17  and locking base  12  and cap  13  together, as discussed in connection with FIGS. 3 c - 3   e.    
     After plug  77  has been inserted, rear portion  53  of lever  51  is bent down and pushed forward, as shown in FIG. 7, until latching arms  57  and  58  engage cap  13  as shown in FIG.  5 . In this position, post  59  bears against the bottom surface of latching arm  41 , thereby preventing its disengagement and further locking cap  13  to base  12 . The under surface of enlarged portion  61  is shaped to allow room for the latch  78  and guard  81  of plug  77 . However, as can be seen latch  78  and guard  81  are inaccessible to an operator so that plug  77  can not be unlatched and removed while actuation lever  51  is in the forward, or switch actuating position. Thus, the butting junction of the ferrules of plugs  63  and  77  cannot be broken or the ferrules otherwise disconnected while power passes through the connection. The only way that disconnection can occur is by the operator&#39;s pulling actuation lever to the rear with the necessary force to cause the latching action of latch projections  73  and  74  to be overcome and the latch effectively freed and portion  53  of lever  51  bent upward for access to arm  78  on plug  77 . Such action, therefore, deactivates the switch  23  and the power is turned off before the operator can unlatch connector plug  77 . 
     FIG. 8 is a perspective view in cross section of the adapter assembly  11  in its passive or deactivated state, as shown in FIG. 6, with actuation lever  51  in its rear position. In this position, latching arm  41  of cap  13  is latched to shoulder  46  of base  12  and latch projection  69  of arm  56  of the actuation lever  51  is engaged with shoulder  68  at the end of slot  47  of the cap. 
     In those instances where it is desired that the adapter  11  have the smallest footprint possible, latching arm  41  may be eliminated. The cap  13  will still be latched to base  12  by means of latching arms  14  and projections  16  in ports  17 . Under other circumstances, however, where footprint is not a pressing consideration, it is preferred that arm  41  be included as part of the cap. 
     From the foregoing it can be seen that a connector plug is insertable into the adapter when the power is off, and that the connector plug cannot be removed from the adapter when the power is on. It requires a positive action by the operator or installer to manipulate the actuation switch first, for inserting the connector plug with the power off, then turning the power on after the plug is in place. 
     The principles and features of the present invention in a preferred embodiment of the invention have been set forth in the foregoing. It is to be understood, however, that the various features of the present invention might be incorporated into other types of adapters and that other modifications or adaptations might occur to workers in the art. For example, the adapter may be, instead of split, a one piece adapter which contains the switch and the actuation lever. All such variations and modifications are intended to be included herein as being within the scope of the present invention as set forth. Further, in the claims hereafter, the corresponding structures, materials, acts and equivalents of all means or step-plus-function elements are intended to include any structure, materials, or acts for performing the functions in combination with other elements as specifically claimed.

Technology Category: 3