Patent Publication Number: US-9407029-B2

Title: Electrical connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(a) to GB 1300845.3, which is entitled “Electrical Connector” and was filed Jan. 17, 2013 in UK Intellectual Property Office. The entirety of the aforementioned application is incorporated by reference herein. 
     TECHNICAL FIELD 
     This invention relates to an electrical connector for terminating an electrical cable, such as a shielded cable. In particular, the invention relates to a so-called “breakaway” connector, which can be firmly engaged with a mating connector but can be quickly and easily disengaged when required. 
     BACKGROUND 
     U.S. Pat. No. 2,761,111 discloses a known breakaway electrical connector for terminating an electrical cable. The electrical connector is arranged to be mechanically engagable with a mating electrical connector to provide an electrically conductive path from the electrical cable to the mating connector. The connectors can be firmly engaged but quickly and easily disengaged when required. 
     The mating electrical connector described in the US patent is a female connector having a receptacle within which is formed an annular groove. An endless coil spring is retained within the annular groove and partially protrudes therefrom. A plurality of elongate contacts is also arranged within the receptacle and maintained in a parallel longitudinal configuration by a dielectric spacing element. 
     The cable-terminating connector described in the US patent is a male connector in the form of a plug. A rearward end of the plug is provided with an opening for routing the cable away from the connector in a longitudinal direction. A forward end portion of the plug is provided with an annular groove which is shaped and dimensioned to receive the protruding part of the endless coil spring when the plug and the receptacle of the mating connector are engaged. A plurality of elongate sprung contacts is also arranged within the plug and maintained in a parallel longitudinal configuration by a dielectric spacing element. 
     The forward tip of the plug is tapered to exert a cam action, whereby an inward thrust of the plug into the receptacle of the mating connector will expand the coil spring to enable the spring to snap into the annular groove formed in the plug, and thus maintain the engagement of the connectors. In this way the sprung contacts of the plug may be held in firm pressure engagement with the fixed contacts of the receptacle to provide the electrically conductive path. The connectors are disengaged by exerting a longitudinal or transverse force on the plug or the cable to thereby expand the coil spring to enable the spring to snap out of the annular groove formed in the plug. 
     A problem associated with the known breakaway connector arrangement disclosed in U.S. Pat. No. 2,761,111 is that tension on the electrical cable can lead to accidental disengagement of the connectors. Furthermore, tension applied on the cable for deliberately disengaging the connectors may cause excessive stress on the connections and lead to damage. 
     GB 2 477 987 discloses an angled electrical connector for terminating an electrical cable and for engaging with a mating electrical connector. The angled connector comprises a body having an engagement portion including a sleeve which extends in a longitudinal first direction for engaging with the mating electrical connector, the body further having an opening for routing conductors of the cable away from the connector. At least one resilient member is arranged on the sleeve of the engagement portion, the resilient member being capable of deforming in a transverse direction perpendicular to the first direction and providing a reaction force for maintaining the engagement of the connector with the mating connector. 
     The opening of the body for routing the conductors of the cable away from the connector is arranged to route the cable in a second direction substantially perpendicular to the first direction. The resilient member comprises a coil spring extending about the sleeve of the engagement portion, the coils of the coil spring having a canted arrangement. 
     In this design, tension on the cable is less likely to lead to accidental disengagement with a mating electrical connector. In particular, the tension on the cable is in a direction which is substantially perpendicular to the direction of a force required for disengaging the connectors. Furthermore, when the mating connector is mounted in a panel, the connectors may be conveniently disengaged by inserting a user&#39;s hand between the panel and the cable to pivoting the cable away from the panel. 
     This invention relates in particular to the use of this type of connector for connections to fabric, i.e. items of clothing. For example, items of clothing may include built in sensors for monitoring physiological parameters of the wearer, and an electrical interface is required to provide those sensor signals to processing apparatus. 
     In this context, there is a need for a design which maintains the advantage that accidental disengagement is prevented by pulling on the cable, but which avoids disengagement by a pivoting action. For example, if one of the connectors is mounted in a flexible panel such as an item of clothing, a force resulting in the pivoting release can arise by accident. 
     BRIEF SUMMARY 
     According to the invention, there are provided connectors as defined in the claims. 
     In one aspect, the invention provides an angled electrical connector for terminating an electrical cable and for engaging with a mating electrical connector, the angled connector comprising: a body having an engagement portion including a sleeve which extends in a longitudinal first direction for engaging with the mating electrical connector, the body further having an opening for routing conductors of the cable away from the connector in a second direction substantially perpendicular to the first direction; and at least one resilient member arranged on the sleeve of the engagement portion, the resilient member being capable of deforming in a transverse direction perpendicular to the first direction and providing a reaction force for maintaining the engagement of the connector with the mating connector, wherein the sleeve comprises a cylindrical inner portion at the base of the sleeve and a tapered portion, such that the opening of the sleeve is larger than the base. 
     This design makes use of a sleeve having a cylindrical part at or near its deepest point, so that release of the electrical connector by pivoting is avoided. Instead, the release needs to be provided by a force along the direction of the sleeve. This is of particular interest for connection to moving objects such as clothing, where lateral forces are likely to be applied to the connector as a result of snagging or contact with objects. The cylindrical portion has a sufficient length to resist pivoting movement of the mated other connector part, but sufficiently short to limit the overall increase in length of the connection. The cylindrical portion may for example extend between 1 mm and 2 mm. 
     The sleeve can comprise a second cylindrical inner portion at the opening of the sleeve. This also resists pivoting, and may have a length of between 0.5 mm and 2 mm. 
     A set of projecting connection pins can be provided in a base of the sleeve. The at least one resilient member can comprise a coil spring extending about the sleeve of the engagement portion, and this coil spring can be arranged in and retained by a groove or channel formed in the sleeve of the engagement portion such that a portion of the coil spring protrudes out of the groove or channel. 
     An alignment notch is preferably provided at a location around the outside of the sleeve. 
     In another aspect, the invention provides an electrical connector for receiving an angled electrical connector, comprising: a projecting connection port, having electrical contacts within an end face of the port; and a protecting collar circumferentially around the connection port, with an alignment opening interrupting the collar, wherein the connection port comprises a cylindrical outer portion at or near the end and a tapered portion set back from the end, such that the size of the connection port is smaller at the end than at the base. 
     This aspect provides the connector with which the angled connector can mate. The projecting port has a design such as to avoid angular movement and thereby resist decoupling by a pivoting action. The collar also resists pivoting and thereby ensures a more secure connection, and the opening provides an alignment feature for the connection operation. 
     As for the other connector part, the cylindrical outer portion has a sufficient length to resist pivoting movement of the mated other connector part, but sufficiently short to limit the overall increase in length of the connection. The cylindrical portion may for example extend between 1 mm and 2 mm. 
     The electrical contacts can comprise recesses in the end face or pads flush with the end face. An alignment projection can be provided within the alignment opening, for example with a tapered end face. 
     The invention also comprises a connector arrangement, comprising the angled electrical connector of the invention and the connector of the invention for mating with it. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the invention will now be described in detail with reference to the accompanying drawings, which are incorporated herein by reference, in which: 
         FIG. 1 a    is a perspective view of a known angled electrical connector according to the invention; 
         FIG. 1 b    is a perspective view of a known electrical connector for mating with the angled connector shown in  FIG. 1 ; 
         FIG. 2  is a perspective view of the connectors shown in  FIGS. 1 a  and 1 b    in the mated configuration; 
         FIG. 3  is a cut-away perspective view showing the connector of  FIG. 1 a    in more detail; 
         FIG. 4  is a cut-away perspective view showing the connector of  FIG. 1 b    in more detail; 
         FIG. 5  shows one part of the connector arrangement of the invention; 
         FIG. 6  shows the connector part of  FIG. 5  with an outer collar; 
         FIG. 7  shows the other part of the connector arrangement of the invention; 
         FIG. 8  shows both parts of the connector arrangement of the invention; 
         FIG. 9  shows how the two connector parts mate in cross section; and 
         FIG. 10  shows in more detail the design of the projecting connector part. 
     
    
    
     DETAILED DESCRIPTION 
     The subject matter of the present invention is described with specificity herein to meet statutory requirements. However, this description is not intended to limit the scope of this patent. Rather, it is contemplated that the claimed subject matter might also be embodied in other ways, to include different elements or combinations of elements similar to the ones described in this document, in conjunction with other present or future technologies 
     The invention provides an angled electrical connector for terminating an electrical cable and for engaging with a mating electrical connector. 
     The invention provides various modifications to the applicant&#39;s previous design of GB 2 477 987 to make the design suitable for use when connecting to a fabric article having one connector part provided at its surface. The particular problem of connections to fabric articles (such as a vest) is that the amount of movement in use, and the likelihood of knocking the connection against other objects, means that accidental disconnection is more likely than in static situations. 
     The design of GB 2 477 987 will first be described, using  FIGS. 1 to 4  from GB 2 477 987. Further details can be found in GB 2 477 987. 
       FIG. 1 a    shows the underside of the known angled electrical connector  1 . The angled connector  1  is a female connector having a receptacle  3  for receiving a male connector (not shown in  FIG. 1 a   ). A plurality of elongate electrical contacts is arranged within the receptacle  3 . 
     The angled connector  1  comprises a metallic outer body  5  and has an engagement portion including a circular sleeve  7  for engaging the male connector. The sleeve  7  has a generally cylindrical outer shape and extends (axially) in a longitudinal first direction. An outer surface of the sleeve  7  is provided with notches  9  which align with corresponding features of the male connector to ensure correct circumferential alignment when the connectors are brought into engagement. An inner surface of the sleeve  7  has a circular cross section and is provided with engagement means for mechanically coupling the connectors, as will be described in more detail hereinbelow. 
     The connector body  5  also has a collar portion  13  extending in a second direction which is perpendicular to the first direction. The collar portion defines an elongate opening for routing the inner conductors of a terminated cable  11  away from the connector  1 . 
       FIG. 1 b    shows an electrical connector  51  intended for mating with the angled connector  1  shown in  FIG. 1 a   . The mating connector  51  is a male connector comprising an outer body  53  formed, for example, of nickel-plated stainless steel. The body  53  of the mating connector  51  has an engagement portion including a longitudinally-extending sleeve  55  for engaging the angled connector  1 . A plurality of elongate electrical contacts is arranged within the sleeve  55  for connection to the tracks of a printed circuit board  57 . An outer surface of the sleeve  55  is provided with engagement means for mechanically coupling the connectors  1 ,  51 . 
     The mating connector body  55  also has an annular mounting flange  59 , a threaded section (not shown in  FIG. 1 b   ) adjacent to the mounting flange  59 , and a lock nut  61  for mounting the connector  51  to an equipment panel  63 . The mounting flange  59  is provided with longitudinally-extending posts  65  which align with the notches  9  formed in the angled connector  1  to ensure correct circumferential alignment when the connectors  1 ,  51  are brought into engagement. 
       FIG. 2  is a perspective view of the connectors  1 ,  51  shown in  FIGS. 1 a  and 1 b    in the mated configuration. As will be seen, in the mated configuration, the angled connector  1  entirely covers the portion of the mating connector  51  which is exposed above the equipment panel  63  in which it is mounted. 
       FIG. 3  shows the angled connector  1  shown in  FIG. 1 a    in greater detail. The Figure shows the connector body  5  and the protective rubber boot  13  described above, together with other features of the connector  1 . Thus, the connector  1  further comprises a resilient member in the form of an endless coil spring  15 . The coil spring  15  is arranged in and retained by an annular groove  17  formed in the inner surface of the sleeve  7  of the outer body  5 . A portion of each coil of the coil spring  15  protrudes from the annular groove, as illustrated. The coil spring  15  has a canted arrangement whereby the coils of the spring are canted with respect to a centerline of the coil spring  15 . Thus, entire coils of the coil spring  15  each define an acute angle with a respective plane normal to the centreline of the spring  15 . A radial cross section of the canted coil spring  15  has an elliptical shape. The protruding portion of the spring  15  is displaceable in a radially outward direction, thereby compressing the spring and causing increased canting, in response to which a reaction force acts in a radially inward direction. 
     The groove  17  in which the canted coil spring  15  is arranged is defined by a pair of spaced apart first and second flanges  19 ,  21  which extend inwardly from the sleeve  7 . The first flange  19  is arranged at a forward end of the sleeve  7  and has a distal end which defines an annular abutment surface  23 . The abutment surface  23  is parallel to the longitudinal (first) direction and is intended for abutting a corresponding surface of the mating connector  51  for preventing transverse displacement of the connectors  1 ,  51  with respect to each other when they are in the fully engaged configuration. 
     The second flange  21  has a distal end which defines a frustro-conical surface. The frustro-conical surface is intended for longitudinally and transversely locating the connector  1  with respect to the mating connector  51  as the connectors  1 ,  51  are brought into engagement. 
     The connector  1  further comprises an electrical contact assembly which is housed within the sleeve  7  of the connector body  5 , behind the second flange  21 . The electrical contact assembly comprises an annular seal  25 , a dielectric spacing element  27  provided with a plurality of through holes extending in the first direction, and a plurality of fixed elongate conductive solder contacts  29  arranged in respective through holes of the spacing element  27  for providing electrical connections. The annular seal  25  of the contact assembly is maintained in pressure contact with the second flange  21  by a resilient retaining ring  31  which is received in a second groove  33  formed in the inner surface of the sleeve  7  and bears against the spacing element  27 . 
     A rearward end of the sleeve  7  is provided with a disc-shaped shielding cap  35  which covers the electrical contact assembly and is attached to the body  5  after the inner conductors of the terminated cable have been soldered to the solder contacts  29 . A space between the electrical connection assembly and the shielding cap  35  may be potted with a sealant material for additional protection against ingress of moisture and other contaminants. 
     The collar portion  37  of the connector body  5  is clearly visible in  FIG. 3 . As described above the collar portion  37  provides an elongate opening extending in the second direction for routing the inner conductors of the cable. An outer surface of the collar portion  37  defines a crimp barrel for receiving the outer conductor, or braid, of the cable and over which a ferrule  39  is crimped in a conventional manner which will be well understood by the skilled person. The collar portion  37  is provided with the protective boot  13 , as illustrated in the Figure, which is maintained in position by engagement with a circumferential flange  41  formed on the outer surface of the collar portion  27 . 
       FIG. 4  shows the mating connector  51  shown in  FIG. 1 b    in greater detail. The Figure shows the connector body  53  and lock nut  61  described above, together with other features of the connector  51 . Thus, the connector further comprises an electrical contact assembly which is housed within the sleeve  55  of the connector body  53 . The electrical contact assembly comprises a resilient seal  67 , a dielectric spacing element  69  provided with a plurality of through holes, and a plurality of elongate conductive solder contacts  71  arranged in respective through holes of the spacing element  69  for providing electrical connections. The solder contacts  71  may, for example, be soldered directly to the conductive tracks of a printed circuit board  57 , as illustrated. The solder contacts  71  are so-called pogo contacts in that they are provided as two parts which can be pressed together against the action of a compression coil spring (not shown) arranged inside the contacts  71 . The use of such sprung contacts ensures a firm pressure engagement between the contacts  29 ,  71  of the two connectors  1 ,  51  when the connectors  1 ,  51  are in the mated configuration. 
     The mounting flange  59  of the mating connector  51  is provided with a groove in its surface which faces the mounting panel  63 . A resilient sealing member, such as a rubber “O” ring is received in the groove for preventing ingress of moisture and other contaminants between the connector  51  and the panel  63 . 
     An outer surface of the sleeve  55  of the connector body  53  is profiled to define a cam surface for bearing against the canted coil spring  15  of the angled connector  1  when the connectors  1 ,  51  are brought into engagement with each other. In particular, a forward end of the outer surface of the sleeve  55  is provided with a substantially frustro-conical (tapered) surface  75  having a diameter which gradually increases away from a leading edge of the sleeve  55 . The frustro-conical surface  75  leads into a circumferential groove  77  which is arranged for receiving the canted coil spring  15  when the connectors  1 ,  51  are in the mated configuration. The frustro-conical surface  75  serves two purposes: firstly, it progressively bears against and displaces the canted coil spring  15  when the connectors  1 ,  51  are brought into engagement, as mentioned above, so that the coil spring  15  is able to compress and then snap into the groove  77 . Secondly, it may cooperate with the corresponding frustro-conical surface of the angled connector  1  to longitudinally and transversely locate the connectors  1 ,  51  with respect to each other as they are brought into engagement. 
     A portion of the outer surface of the sleeve  55  of the connector body  53  adjacent to the mounting flange  59  is provided with an annular abutment surface  79 . The abutment surface  79  is parallel to the connector axis and is intended for abutting the corresponding surface of the angled connector  1  for preventing transverse displacement of the connectors  1 ,  51  with respect to each other when they are in the fully engaged configuration. 
     This invention provides various design changes to make the connector more suitable for use in fabric/textile articles, i.e. where the “equipment panel”  63  in  FIG. 1 b    is a flexible substrate. The connection mechanism remains essentially the same, with the same use of a circumferential spring which is a snap fit into a channel. 
     In one embodiment, the modifications comprise: reversing the gender, so that the fixed pins are part of the removable connector part, and the pin recesses or contact pads are on the receptacle part on the fabric side; improvement of the mating arrangement for easier alignment; a wipe clean design for the receptacle part of the connector on the fabric side; and layout change to avoid pivoting disconnection. 
       FIG. 5  shows the receptacle part  80  of the connector, which is to be applied to the fabric substrate. The plug in part will be termed the “connector part”, in contrast to the “receptacle part”. 
     The receptacle part has a projecting connector port  82 , at the end of which are provided the pin recesses  81 , has a different design to eliminate the possibility of a pivoting release of the connector. 
     The projecting connector port  82  has a cylindrical portion  83  at or near its end, instead of a tapered portion. The cooperation of this cylindrical portion with a corresponding cylindrical part of the connector part resists pivoting movement. The addition of a cylindrical section increases the overall projection length (i.e. the height of the connector), but it is preferably still as small as possible while preventing the rip away of the connector. 
     The projecting connector port still has a tapered part  84  so that the end face is smaller than the base. This relaxes the alignment of the two connector parts. 
     The projecting connector port also has a cylindrical part  85  at its base. A recess  86  is between the base and the tapered section  84  for receiving the spring, as in the designs of  FIGS. 1 to 4 . 
     In the connected state, there is an area of interface between the two connector parts which is parallel to the projection axis. This prevents pivoting release of the connection. 
     The projecting connector port is on the outside of a garment. Connecting pins  87  project through the receptacle for connection to a PCB inside the garment, which in turn connects to body sensors, for example. 
     By providing the pin recesses or pads at the end of the projecting connector port  82  instead of the connection pins, the surface is a wipe clean surface. Furthermore, the pin contacts  81  can be openings or else they can be contact surfaces (for example spring loaded) for making surface contact with the connection pins of the plug (described below) instead of an interference pin-and-socket connection. 
     If contact surfaces are used, they can be flush with the end surface of the connector or just under the surface to prevent wear and accidental shorting. 
     To improve the self-alignment, an orientation key  88  has a large taper. The width of the orientation key  88  at its distal end is for example less than 70% of its width at the widest point. 
     This means that the range of the initial angle of alignment which leads to correct coupling can be increased. The taper angle is in the range 30 to 60 degrees to the plane parallel to the end face of the projecting connector port  82 , for example 40 degrees. 
       FIG. 6  shows the receptacle part  80  fitted within a surrounding collar  90 . 
     The projecting connector port  82  projects within the collar  90  which is integrated into the fabric garment. The collar  90  has a horse shoe shape with an opening  92  at the location where the cable extends from the cable plug part. The opening  92  has a width which enables the cable plug part to be fitted with the permitted range of misalignment which is tolerated by the tapered orientation key design. 
     The collar  90  protects the connector from lateral forces and provides additional protection from snagging of the interface. The collar  90  can project to approximately the same height as the projecting connector port  82 . The top part of the collar has a cylindrical surface  94  which is to engage with the outside of the projecting connector port, and this also functions to prevent pivoting. In this way, the connector part comprises an annulus having an end part which is sandwiched between the projecting connector port  82  and the collar  90 . 
       FIG. 7  shows the connector part  100  of the connector, which is to be provided at the end of a cable  102 . 
     The connection pins  104  are provided at the base of a recess, and they project a shorter distance than the depth of the recess so that the connecting part can also be wiped clean. 
     An orientation key recess  106  is provided for receiving the orientation key  88 , with a tapered surface at its deep end to match the taper of the key  88 . 
     As mentioned above, the receptacle part  80  is for example fitted to a fabric garment and the connector part  100  enables sensor data to be received from the garment or enables control signals to be provided to the garment. 
       FIG. 8  shows the two connector parts being brought into engagement.  FIG. 8  also shows that the connector part (the plug) can be fully overmoulded to give additional protection and grips to assist with the required straight mating and un-mating operation. 
     The receptacle part  80  can be moulded into a garment section, or glued, instead of being mounted using a nut and threaded shaft as in the example above. A thin (low profile) PCB can be used with low termination height, to reduce the bulk inside a garment. 
       FIG. 9  shows in cross section the connection between the receptacle part  80  and connector part  100 . The two cylindrical receptacle parts  83 , 85  are shown engaged with corresponding parts of the connector part. The connector part has a sleeve  110  for engaging over the projecting connector port  82  of the receptacle. One of the corresponding cylindrical connector parts  112  is at the base of the sleeve  110 , and the other  114  is at the sleeve opening. The sleeve  110  also has a tapered part  116 . The two cylindrical parts thus function as mating surfaces which resist pivoting movement. 
       FIG. 10  shows in more detail the change in the shape of the receptacle part compared to the previous design. It shows the previous design to the left (although without the pins shown) and the modified design to the right. In the example shown, the end cylindrical part  83  has a length of 1.32 mm and the base cylindrical part  85  has a length of 0.96 mm. The overall projecting length is 1.7 mm longer than the previous design. 
     The cylindrical part is described as at the end of the projection connecting port  82 . The may be a small taper at the very end, and this is shown in the drawings. The term “end” should be understood accordingly. The provision of the parallel connection between the connecting part at receptacle as far out from the base of the receptacle provides greatest prevention of pivoting, since the pivot axis is in the plane of the base of the receptacle part. Thus, the further out the cylindrical portion, the greater the distance from the pivot axis and therefore the greater the resistance to pivoting. 
     The invention can be used for connecting to sensors in body armour, for example. 
     A specific embodiment of the invention has been described above. Various changes and modifications may be made to the specific embodiment without departing from the invention. 
     For example, the canted coil spring may be arranged on the mating connector and the cam surface arranged on the angled connector. The canted coil spring could be replaced by a plurality of discrete spring elements spaced about the circumference of either connector.