Abstract:
The locking fastening device for two-part electrical connectors with axial coupling includes two male mistake-proofing mechanisms and two female mistake-proofing mechanisms included in the parts. The mistake-proofing mechanisms are positioned on both sides of the contacts of the two parts of the male and female electrical connector and respectively includes at least a protuberance and a bore axially cooperative to produce the fastening of the parts, during coupling.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    See Application Data Sheet. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not applicable. 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB) 
       [0004]    Not applicable. 
       STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR 
       [0005]    Not applicable. 
       BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
       [0006]    The present invention relates to a locking fastening device for two-part electrical connectors with axial coupling. The technical field to which the invention relates therefore pertains first to connector technology, and more particularly pertains to the field of secure connections related to aeronautic and military applications. 
       2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98 
       [0007]    In these fields, the quality and sustainability of the connection implemented, in particular a primarily electrical connection, are crucial, and they first involve mechanical coupling characteristics. It is imperative for the fastening of the two parts of the connectors to be guaranteed, and for any untimely breaking to be prohibited and made practically impossible by the system. It should be noted that the connectors in question also perform a mistake-proofing function, which occurs upstream from the sustainability and securing function of the connection, and may appear less decisive, even though it also contributes to security: in any case, it prevents an electrical connection from being established between two incompatible male and female connectors, respectively, which could result in a poor signal transfer that could potentially be disastrous and in fine equally detrimental to security. 
         [0008]    The connectors affected by the present invention are in particular those that obey the strict normative characteristics inherent to the aeronautics industry and military applications, the technical constraints of which are listed in standard EN3545 inter alia. 
         [0009]    They involve, inter alia, the implementation of mechanical locking of the two parts of the connector when they are coupled and when the electrical connection is in place and functional. The aim is to eliminate any possibility of accidental disconnection, i.e., unexpected, unplanned and not done by human intervention. 
         [0010]    It is consequently also the primary aim of the locking fastening device according to the present invention, the latter nevertheless greatly exceeding this aim inasmuch as it proposes innovations resulting certain drawbacks of the commercially available connectors and making the device very attractive from an industrial perspective. 
         [0011]    Thus, in the known connectors, mistake-proofing is commonly associated with fastening of the parts of the connector by screwing, the applicable standards then requiring a monitoring measurement of the tightening torque. This is done by a dynamometric tool providing a precise indication of the measured torque, this tool continuously monopolizing one of the operator&#39;s hands. The performance time of the measurement obviously affects the assembly rhythms, imposing non-negligible installation and maintenance times, in particular in light of the number of connectors to be fastened or verified. 
         [0012]    The appropriate tools for performing the tightening, such as dynamometric keys, use bushes suitable for the mechanical connection to be monitored, which are often lost when they accidentally detach from the rest of the tool. Yet in the aeronautic construction field in particular, it is absolutely essential to look for and find a bush that has become detached, since any risk of damage to the aircraft during flight due to this unruly mechanical part is unacceptable. The search, according to the configuration of the establishment site of the connection, may take time, which is also detrimental to assembly rhythms. 
         [0013]    Furthermore, the quick analysis of the connections and their locking is in no way obvious with traditional screwed or clipped connectors, since the state of the connection is generally not immediately visible and the tightening torques are only rarely able to be viewed and, in the scenario of quarter-turn systems, the locking may have been done only partially without this being apparent. The monitoring of the exact condition of the connections therefore also requires a lengthy intervention time, and the time-related economic impact of which is unfavorable. 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    The invention provides an effective technical solution to the raised questions, which is also particularly astute inasmuch as it is fully possible to carry it out in the housings of existing connectors, simply by substituting certain components, which in passing procures a substantial economic advantage. 
         [0015]    As a reminder, the invention applies to two-part electrical connectors with axial coupling known in itself, i.e., including two male mistake-proofing mechanisms and two female mistake-proofing mechanisms included in said parts, these mistake-proofing mechanisms being positioned on both sides of the contacts of these connectors. 
         [0016]    Traditionally, these male and female mistake-proofing mechanisms respectively comprise at least one protuberance and a bore able to cooperate axially to fasten the parts during coupling. 
         [0017]    According to the design specific to the invention:
       the protuberance of the male mistake-proofing mechanism includes at least one flexible element protruding from its surface abutting with the female mistake-proofing mechanism, able to be axially inserted into the bore of said female mistake-proofing mechanism and including at least one axial blocking member by radial expansion of the flexible element in said bore;   the bore of the female mistake-proofing mechanism includes an expansion space for the flexible element of the male mistake-proofing mechanism, provided with axial blocking means for the blocking member(s) of the male mistake-proofing mechanism;   a push-piece is associated with the female mistake-proofing mechanism, movable within the latter and including guide means between an inactive position without axial blocking and an active position with axial blocking of the two mistake-proofing mechanisms by insertion of the push-piece into the flexible element of the male mistake-proofing mechanism to push it back radially, guide means actuating locking means of the axial blocking.       
 
         [0021]    This original design allowing guiding and locking resulting from the guiding eliminates the need to use a tool, of any kind, and allows the operator to perform the assembly/disassembly with one hand. Time savings and work comfort are thus greatly improved. 
         [0022]    According to one possible configuration, the locking means of the push-piece include return means inserted between the female mistake-proofing mechanism and the push-piece stressing the push-piece in rotation, the guide means initiating the rotation actuating the locking of the push-piece in the female mistake-proofing mechanism. 
         [0023]    This involves a system that can be qualified as self-locking inasmuch as the return means constantly tend to stress the push-piece in the locked position, and inasmuch as the handling of said push-piece in the direction of axial blocking of the mistake-proofing mechanisms automatically actuates said blocking due to the action of the guide means. 
         [0024]    According to one possibility, said guide means of the push-piece in the female mistake-proofing mechanism can consist of radial studs, one cooperating with L-shaped housings of the other, performing a bayonet-type connection. This type of connection indeed involves a combination of a rectilinear movement and a rotating movement, in line with the logic set out above. 
         [0025]    According to one configuration of the invention, the flexible element of the axial protuberance of the male mistake-proofing mechanism can consist of at least one axial flexible wall of the protuberance, said wall being provided at its free end with a rim protruding toward the outside of the protuberance. Said rim then forms the axial blocking member of the male mistake-proofing mechanism. 
         [0026]    According to one possible configuration, the protuberance includes two flexible elements that consist of the wall of a hollow cylindrical barrel divided in two by axial slits formed up to the vicinity of the abutment surface of the male mistake-proofing mechanism at the female mistake-proofing mechanism. The barrel is then for example provided with an end collar, oriented radially toward the outside of the barrel and the outer diameter of which does not exceed that of the bore, the collar portions of the half-barrels making up the flexible elements forming the axial blocking members of the male mistake-proofing mechanism. 
         [0027]    It will be noted that this does not involve the traditional clipping system, since the flexible element(s) are not stressed in flexion during the insertion of the protuberance in the bore, since, for example, the outer diameter of the collar is smaller than or equal to the inner diameter of the bore. The axial blocking comes from the expansion of said elements, caused in case of activation of the system by the axial movement of the push-piece, which moves the collar into the space provided to that end in the female mistake-proofing mechanism. 
         [0028]    A solution consists of having at least one elastic element, in the case at hand the wall(s), that deforms with assembly is also possible and procures an additional function in that it allows pre-maintenance of the connector before locking. 
         [0029]    In practice, the bore of the female mistake-proofing mechanism can for example include, to allow this expansion, a radial space widening its inner diameter and able to house the blocking member of each flexible element. This space can then have a projection situated at a distance from its abutment surface with the male mistake-proofing mechanism substantially equal to the distance separating the blocking members from the abutment surface of the male mistake-proofing mechanism. Once this distance is traveled during the insertion of the axial protuberance of the male mistake-proofing mechanism into the bore of the female mistake-proofing mechanism, the conditions for a potential expansion are met: this is done only during activation of the push-piece. 
         [0030]    When the push-piece is actuated, i.e., when it is inserted inside the female mistake-proofing mechanism, the aforementioned bayonet guiding system is used. According to one possible configuration, a torsion spring is inserted between the female mistake-proofing mechanism and the push-piece, continuously stressing the push-piece in rotation. Studs protruding radially from the push-piece are further guided each in a notch formed in the inner wall of the female mistake-proofing mechanism. According to the invention, this notch for example has a locking flank provided with a first rectilinear portion emerging after a hard spot in a rounded portion that loops over a rounded unlocking flank ending with a second rectilinear portion across from the first. 
         [0031]    The combined movement targeting the locking is ensured by the locking flank of the notch, the locking becoming effective after the passage past the threshold made up of the hard spot and the slight subsequent withdrawal of the push-piece into the rounded flank due to traditional axial return means of this type of connection, of the lock washer type. It should be noted that the elastic properties of seals inserted between the parts of the connectors also play a role in this respect. 
         [0032]    Additionally, according to the invention, a device retaining the push-piece in the female mistake-proofing mechanism such as a ring equips the perimeter of the push-piece. This ring is movable for example in a cylindrical peripheral recess of the female mistake-proofing mechanism defined on one side by a rim in which the notches emerge, and on the other side by a shoulder situated at a distance from the rim adjacent to the axial length of said notches. The axial travel is therefore provided so that the assembly can be found on the one hand in the inactive disconnection position without the push-piece being free to detach from the female mistake-proofing mechanism, and on the other hand in the active axial and locked blocking position of the mistake-proofing mechanisms, and consequently of the two parts of the connector equipped with a device according to the invention. 
         [0033]    According to one possible design, non-limiting with respect to the invention, the torsion spring can be positioned in an annular housing of the body of the push-piece, between a central cylindrical core whereof the free end is provided to push the flexible elements back and a low cylindrical peripheral wall. The branches of said spring are then for example housed one in an axial orifice of the female mistake-proofing mechanism and the other in an axial slit formed in the periphery of a low wall, as well as in the retaining ring housed in a peripheral recess of the body of the push-piece adjacent to the low wall, and lastly in the portion of said body adjacent to the other side of said recess and from which the studs protrude. 
         [0034]    The torsion spring consequently indeed bears simultaneously on the female mistake-proofing mechanism, one of the walls of the axial orifice that receives one of the branches, and the push-piece, on a wall opposite—relative to the rotation—the slit described above. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0035]    The invention will now be described in more detail, in reference to the appended figures. 
           [0036]      FIG. 1  is a partial axial sectional view of a connection device according to the invention. 
           [0037]      FIGS. 2 to 5  show perspective views of the different components of said connection device, namely, respectively, the male mistake-proofing mechanism ( FIG. 2 ), the female mistake-proofing mechanism ( FIG. 3 ), the push-piece ( FIG. 4 ) and the torsion spring ( FIG. 5 ). 
           [0038]      FIG. 6  is an enlarged sectional view of the interaction between the mistake-proofing mechanisms in the non-blocked and unlocked position. 
           [0039]      FIG. 7  shows another enlarged sectional view equivalent to  FIG. 6 , showing the interaction between the mistake-proofing mechanisms in the blocked and locked position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0040]    In reference to  FIGS. 1 to 5 , the device according to the invention applies to secure electrical connectors including a female part  1  provided with female mistake-proofing mechanisms  3  (only one of which is visible in the partial view) and a male part  2  provided with male mistake-proofing mechanisms  4  (only one of which is visible for the same reason). The male mistake-proofing mechanism  4  includes a cylindrical main body  40  from which a protuberance  41  made up of two flexible elements  42 ,  43  axially protrudes. In practice, the protuberance  41  is made up of a divided hollow barrel in said flexible elements  42 ,  43  by the removal of two portions of the peripheral wall of the barrel  41  up to the base of the latter, at the abutment surface  44  of the male mistake-proofing mechanism  4 . At the free end of the flexible elements  42 ,  43 , portions  45 ,  46  of an outer collar of the barrel extend toward the outside of the latter, in a substantially radial direction. The mistake-proofing mechanism  4  also includes a hexagonal head  47  housed in a recess  21  with a corresponding shape of the male part  2  of the connector, preventing any relative rotation. 
         [0041]    A ring  22  is positioned in a peripheral recess  48  of the mistake-proofing mechanism  4 , for the axial retention of the latter in the part  2 . Axial blocking also results from a nut  23  and a blocking washer  24 . 
         [0042]    The female mistake-proofing mechanism  3  includes a first hexagonal portion  31  that blocks its rotation in a housing  11  of the part  1  making up the female connector. The hollow barrel  32  includes an inner bore  33  and an annular recess  34  intended to receive an axial retaining ring  12  clipped on a shoulder  13  of the part  1 . The hexagonal portion  31  of the mistake-proofing mechanism  3  also has L-shaped notches  35  for the bayonet-type connection, positioned opposite one another and only one of which is visible in  FIG. 3 . 
         [0043]    The push-piece  5  includes a cylindrical core  51 , defining, with a low peripheral wall  52 , a housing  50  for the spiral body  61  of the spring  6 . The push-piece  5  also includes a peripheral annular recess  53  for the retaining ring  54 . Only one stud  55  from among the two situated opposite one another is visible in  FIG. 4 , said studs  55  being provided to cooperate with the notches  35  of the female mistake-proofing mechanism  3 , in the bayonet guiding connection. A gripping handle  56  allows manipulation by the operator, which therefore does not require any tools. An axial slit  57  is used to house one of the branches  62 ,  63  of the torsion spring  6 . 
         [0044]    In the state of  FIG. 1 , the connection is not finalized, it is not axially blocked or locked, it is in the same state as in  FIG. 6 , i.e., with the hub  51  of the push-piece located near the flexible elements  42 ,  43  of the male mistake-proofing mechanism  4 . In  FIGS. 6 and 7 , the small circle corresponds to the axial blocking zone, and the large circle corresponds to the locking zone in the blocked position. The state of the connection is intermediate, one is in the presence of an activated state that has begun, an axial thrust of the push-piece  5  already having been initiated. 
         [0045]    First examining the zone shown by the small circle in  FIG. 6 , the outer collar  45 ,  46  of the flexible elements  42 ,  43  is not yet pushed radially into the expansion space  36  provided in the female mistake-proofing mechanism  3 . As shown, in this inactivated state, because the outer diameter of these collars  45 ,  46  is not larger than the inner diameter d of the bore  33 , no axial blocking is yet possible. 
         [0046]    In the lower part “covered” by the large circle, the studs  55  are already engaged in a rectilinear portion of the notches  35 , below the hard spots  37  marking the directional change of the push-piece  5 . The latter is indeed stressed in rotation as of the beginning of the movement by the torsion spring  6 , which is compressed between the slit  57  of the push-piece  5  and an orifice (not shown) inside the female mistake-proofing mechanism  3 , but it cannot rotate when it is upstream from the hard spots  37 . The ring  54  does not oppose the movement, it is movable in a cylindrical peripheral recess  38  of the female mistake-proofing mechanism  3  closed by a rim  39   a  in which the slots  35  emerge, and limited in the upper part by a shoulder  39   b.  The distance between them is close to the axial length of the slots  35 , which guarantees that when the device is deactivated, the push-piece  5  is retained such that the studs  55  are ready to be activated, and are situated at the inlet of the notches  35 , thereby allowing the accumulation of energy in the spring.  6 . In the unlocking phase, which involves the excursion of the push-piece  5  furthest from the inside of the female mistake-proofing mechanism  3 , the stop formed by the shoulder  39   b  does not oppose the upward movement of the ring  54 . 
         [0047]    In reference to  FIG. 7 , the connection is activated, i.e., the parts  1  and  2  of the connector are axially blocked and locked. The movement in the axial direction of the push-piece  5  in the female mistake-proofing mechanism  3  triggers the self-locking in the manner explained below. In reference to the zone covered by the small circle, more particularly related to the axial blocking function, the latter results from the fact that the core  51  of the push-piece  5  has moved axially enough to separate the flexible elements  42 ,  43  such that the collar portions  45 ,  46  are now in the space  36 , with a facing surface of a projection  136  of the expansion space  36  that prevents any axial withdrawal of one of the parts  1 ,  2  relative to the other  2 ,  1 . 
         [0048]    At the same time, the studs  55  having arrived at the hard spots  37 , the push-piece  5  is rotated by the spring  6 , which releases its energy at the entry for the studs  55  in the non-rectilinear portions of the slots  35 . Past the hard spots  37 , said studs descend again slightly into the rounded part of the openings, locking the connection by releasing axial energy, for example, by an elastic seal inserted between the two parts  1 ,  2  of the connector according to the invention. The unlocking is done very simply by reverse rotation and pulling of the push-piece is (to block the latter in the non-locking zone) by the operator. 
         [0049]    The configuration described in reference to the figures is of course not exhaustive with respect to the invention, which on the contrary encompasses the shape and structure alternatives that relate to the various components and organize the same functions, inasmuch as they fall within the definition of the claims.