Abstract:
A latch assembly includes a body member defining a cavity and including at least two spaced apart, opposed, relatively displaceable arms. A latch structure is located on at least one of the arms. A deformable elastomeric core is disposed in the cavity to resist convergent displacement of the arms. The elastomeric core is responsive to convergent displacement of the arms to provide a spring force biasing the arms apart.

Description:
FIELD OF THE INVENTION 
     The present invention relates to locking devices and, more particularly, to latches for securing connectors in engagement. 
     BACKGROUND OF THE INVENTION 
     Personal electronic devices such as radiotelephones and the like are becoming smaller and smaller. The reduction in the sizes of many components of these devices often results in a loss of strength and durability. Additionally, smaller devices tend to encourage portability and handling and, as a result, increased exposure to impacts and other stresses. Further, these smaller components may require greater dexterity to operate without damage. 
     Electrical connectors for personal electronic devices in particular have been steadily miniaturized to accommodate smaller housings, larger numbers of connector parts and aesthetic design demands. It is often very important that connectors such as electrical accessory connectors maintain a complete and reliable connection when in use. Unfortunately, such connectors are often subjected to repetitive, heavy-handed and, in some instances, damaging use by operators. 
     Latch mechanisms for securing connectors to personal electronic devices in particular are often subjected to abuse and repetitive use. The latch mechanisms should provide sufficient mechanical strength to keep the connector coupled to the device. For many applications, it is highly desirable that the latch mechanisms be of a passive locking design, i.e., allowing the user to disengage the connector by simply pulling it from an associated receptacle. However, passive locking latch mechanisms may be more prone to failure. 
     SUMMARY OF THE INVENTION 
     According to embodiments of the present invention, a latch assembly includes a body member defining a cavity and including at least two spaced apart, opposed, relatively displaceable arms. A latch structure is located on at least one of the arms. A deformable elastomeric core is disposed in the cavity to resist convergent displacement of the arms. The elastomeric core is responsive to convergent displacement of the arms to provide a spring force biasing the arms apart. 
     The latch structure may include a retention barb extending outwardly from at least one of the arms. Preferably, the elastomeric core is directly secured to the body member. The elastomeric core may be interposed between the arms. 
     According to embodiments of the present invention, a latch assembly includes a body member including first and second opposed arms. The arms are relatively movable from a first, spaced apart position to a second, more closely adjacent position. An elastomeric core is interposed between the arms such that, when the arms are moved from the first position to the second position, the elastomeric core is elastically deformed and exerts an expansive spring force biasing the arms to the first position. Preferably, the elastomeric core is directly secured to each of the arms. A latch structure may be located on at least one of the arms. 
     According to further embodiments of the present invention, an electrical connector assembly includes a connector body and an electrical contact mounted on the connector body. A latch assembly is mounted on the connector body. The latch assembly includes a body member defining a cavity and including at least two spaced apart, opposed, relatively displaceable arms. A latch structure is located on at least one of the arms. A deformable elastomeric core is disposed in the cavity to resist convergent displacement of the arms. The elastomeric core is responsive to convergent displacement of the arms to provide a spring force biasing the arms apart. 
     According to further embodiments of the present invention, an electrical connection assembly includes a receptacle and an electrical connector assembly. The receptacle includes a hole and a first electrical contact. The electrical connector assembly includes a connector body and a second electrical contact mounted on the connector body and adapted to engage the first electrical contact. A latch assembly is mounted on the connector body and is adapted to engage the receptacle. The latch assembly includes a body member defining a cavity and including at least two spaced apart, opposed, relatively displaceable arms. The arms are adapted for insertion into the hole of the receptacle. A latch structure is located on at least one of the arms. The latch structure is adapted to removably secure the latch assembly to the receptacle. A deformable elastomeric core is disposed in the cavity to resist convergent displacement of the arms. The elastomeric core is responsive to convergent displacement of the arms to provide a spring force biasing the arms apart. 
     According to further aspects of the present invention, a method of securing a latch assembly to a receptacle is provided. The latch assembly includes a body member defining a cavity and including at least two spaced apart, opposed, relatively displaceable arms, and further includes a deformable elastomeric core disposed in the cavity. The method includes inserting the arms into a hole in the receptacle such that the arms are compressed and the elastomeric core is thereby elastically deformed such that the elastomeric core exerts an expansion spring force on the arms. The method may include positioning the arms such that at least portions of the arms are disposed in the hole and a latch structure on at least one of the arms interlocks with a portion of the receptacle to resist removal of the latch assembly from the receptacle. 
     Objects of the present invention will be appreciated by those of ordinary skill in the art from a reading of the Figures and the detailed description of the preferred embodiments which follow, such description being merely illustrative of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a latch assembly according to the present invention; 
     FIG. 2 is a perspective view of a connector assembly incorporating the latch assembly of FIG. 1; 
     FIG. 3 is a top view of the latch assembly of FIG. 1; 
     FIG. 4 is a side view of the latch assembly of FIG. 1; 
     FIG. 5 is a front end view of the latch assembly of FIG. 1; 
     FIG. 6 is a rear end view of the latch assembly of FIG. 1; 
     FIG. 7 is a fragmentary, side view of the connector assembly of FIG.  2  and an associated receptacle, wherein the connector assembly and the receptacle are shown prior to insertion of the connector assembly into the receptacle; 
     FIG. 8 is a fragmentary, side view of the connector assembly and the receptacle of FIG. 7, wherein the latch assembly is partially inserted into the receptacle; 
     FIG. 9 is a fragmentary, side view of the connector assembly and the receptacle of FIG. 7, wherein the latch assembly is fully inserted into the receptacle and disposed in a latched position; 
     FIG. 10 is a perspective view of a latch assembly according to a further embodiment of the present invention; and 
     FIG. 11 is a perspective view of a latch assembly according to a further embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. 
     With reference to FIGS. 1-9, a latch assembly according to the present invention is shown therein and generally designated  100 . The latch assembly  100  may be incorporated into a connector assembly  10  as shown in FIGS.  2  and  7 - 9 . The latch assembly  100  may be used to removably secure the connector assembly  10  to an associated article such as an electronic device (e.g., a handheld radiotelephone). As will be appreciated by those of ordinary skill in the art upon reading the description herein, the latch assembly  100  may be substituted for latch mechanisms or locking devices such as those described in U.S. Pat. No. 5,848,456 to Sjöqvist and co-pending U. S. patent application Ser. No. 09/528,642, filed Mar. 20, 2000 (the disclosures of which are hereby incorporated herein by reference in their entireties), as well as other latching mechanisms that interconnect two components. 
     As best seen in FIG. 1, the latch assembly  100  extends along an insertion axis A—A (FIG. 3) between a base end  102  and a leading end  104 . For the purposes of explanation, the latch assembly  100  further defines a first transverse axis T—T (FIG. 3) and a second, perpendicular transverse axis D—D (FIG.  5 ). Generally, the latch assembly  100  has a base portion  120  on the base end  102  and a latch head  140  on the leading end  104 . 
     The latch assembly  100  includes a body member  110 . The body member  110  is generally U-shaped and defines a cavity or channel  137  and an end opening  136  communicating with the cavity  137 . As discussed in more detail below, an elastomeric core  150  is disposed in the cavity  137  and is secured to the body member  110 . The elastomeric core  150  provides increased spring force to the latch assembly  100 . 
     The body member  110  includes a pair of opposed side walls  124  and an end wall  122  extending between the side walls  124 . A pair of opposed cantilever arms  130  extend from the side walls  124 . The arms  130  and the side walls  124  form shoulders  126 . Preferably, the arms  130  have a substantially uniform thickness N (see FIG.  3 ). Preferably, if the body member is formed of a thermoplastic, the nominal width E between the arms  130  is at least 1 millimeter, and, more preferably, is between about 1.2 and 1.6 millimeters. 
     Latch structures, more particularly outwardly extending barbs  132 , are formed on the ends of the arms  130  adjacent the leading end  104 . The barbs  132  include retention edges  132 A. Preferably, the retention edges  132 A each define an angle M with respect to the axis A—A of at least about 100 degrees, and more preferably of between about 100 and 130 degrees. The arms  130  further include inwardly tapered leading edges  133 . The arms  130  terminate at respective ends  134  which define the opening l 36 . 
     At least a portion, and preferably all, of the body member  110  is formed of a deformable material to allow the arms  130  to be displaced or bent inwardly and outwardly (i.e., in a direction generally parallel to the axis T—T) between a relaxed position as shown in FIGS. 1-6 and a compressed position as shown in FIG. 8 without breaking. The body member  110  is preferably formed of a rigid or semi-rigid material which is able to sustain relatively large deflections without yielding. More preferably, the body member material has a Young&#39;s modulus of between about 778 and 3100 MPa. Preferably, the body member  110  is integrally formed. More preferably, the body member  110  is unitarily injection molded. However, the body member  110  may be formed from multiple pieces which are adhered, bonded or mechanically secured together. Preferably, the body member  110  is formed of a polymeric material, more preferably a thermoplastic. More preferably, the body member  110  is formed of nylon 6/6 (e.g., Stanyl TW341™ from DSM Engineering Plastics), polycarbonate (e.g., Lexan 101™ from General Electric), or a polycarbonate/copolymer blend (e.g., Ultem 1110F™ from General Electric). Alternatively, the body member  110  may be formed of metal. 
     Illustratively and as shown, the elastomeric core  150  extends continuously from the end wall  122  to a terminal end  154  of the elastomeric core  150  adjacent the opening  136 . Preferably and as shown, the terminal end  154  is disposed forwardly beyond the body member  110 . The elastomeric core  150  is bonded to the interior surfaces  120 A of the walls  122 ,  124  and to the interior surfaces  130 A of the arms  130 . 
     The elastomeric core  150  is formed of a suitable elastomer. Preferably, the elastomeric core  150  is formed of a thermoplastic elastomer, and more preferably of a thermoplastic molding grade elastomer. Preferably, the elastomer has a durometer of at least Shore A of 20, more preferably of between about Shore A of 20 and Shore A of 65. Suitable and preferred materials include Santoprene™, a thermoplastic elastomer available from Advanced Elastomer Systems, and Hercuprene™ S2954-BX2, a thermoplastic elastomer available from Jvon/Hercuprene Thermoplastic Elastomers Products. 
     Preferably, the latch assembly  100  is formed using an injection molding process. More preferably, the latch assembly  100  is formed using a two-shot molding process whereby the body member  110  is first formed by injection molding, and the elastomeric core  150  is thereafter formed within the body member  110  by a second injection molding step. Preferably, the materials of the body member  110  and the elastomeric core  150  are selected such that the materials will sufficiently bond to one another. Additionally, additionally or alternatively, an adhesive may be employed to secure the elastomeric core  150  to the body member  110 . 
     As best seen in FIGS. 1 and 5, in the illustrated preferred embodiment, the elastomeric core  150  does not entirely fill the cavity  137 . With reference to FIG. 5, the thickness S of the body member  110  is greater than the corresponding thickness R of the elastomeric core  150 . As a result, opposed expansion recesses G are defined between the outer surfaces  150 A and  150 B of the elastomeric core  150  and the adjacent outer surfaces  110 A and  110 B of the body member  110 , respectively. Preferably, the thickness S is at least about 10 percent greater than the thickness R. 
     With reference to FIG. 2, the connector assembly  10  is exemplary of the types of connector assemblies with which the latch assembly  100  may be employed. The connector assembly  10  includes a connector body  12 . A passage  14  is formed in the connector body  12 . The latch assembly  100  is secured in the connector body  12  such that the base portion  120  is mechanically keyed, adhered and/or bonded within the connector body  12  and the arms  130  extend through the passage  14  such that parts thereof, including the head  140 , are exposed. An electrical lead  16  extends from the connector body  12  adjacent the latch assembly  100  and is preferably movable and outwardly spring biased such that the lead  16  may be pushed into the connector body  12 . 
     With reference to FIGS. 7-9, the connector assembly  10  and the latch assembly  100  may be used in the following manner and in cooperation with a receptacle  17  defining a hole  17 A and having an electrical contact  18 . The receptacle  17  may be, for example, a handheld radiotelephone or other personal electronic device. 
     FIGS. 7-9 illustrate the process for removably securing the connector assembly  10  to the receptacle  17  and, more particularly, the process for inserting the latch assembly  100  into the receptacle  17 . In FIG. 7, the latch assembly  100  is shown being aligned with the receptacle opening  17 A such that the leading edges  133  are positioned adjacent the edges of the opening  17 A. The latch assembly  100  normally assumes the relaxed orientation as shown in FIG. 3 when no external forces are applied. The width H of the opening is less than the maximum width W (see FIG. 3) of the arms  130  in the relaxed position such that an insertion force in the direction F and along the axis A—A must be applied. 
     The semi-rigid body member  110  and, more particularly, the leading edges  133  provide bearing surfaces for guiding the latch assembly  100  into the hole  17 A. As the latch assembly  100  is forced into the hole  17 A, the sloped leading edges  133  engage the edges of the hole  17 A. Upon applying the necessary insertion force and as the leading edges  133  enter the hole  17 A, the arms  130  are compressed inwardly toward one another. The barbs  132  continue to contact and apply a spring force against the receptacle edges as the latch assembly  100  slides through the opening  17 A. 
     Notably, in order to compress the arms  130  sufficiently to allow the barbs  132  to pass through the hole  17 A, it is necessary to deflect one or both of the arms  130  and also to elastically deform the elastomeric core  150 . Accordingly, the latch assembly  100  presents outward (i.e., expansion) spring forces in the directions as indicated by the arrows B (FIG. 8) which urge the arms  130  outwardly. The spring forces include the spring force resulting from the deflection of the arms  130  and also the spring force resulting from the deformation of the elastomeric core  150 . Preferably, the elastomeric core  150  bulges outwardly parallel to the axis D—D and also outwardly along the axis A—A through the opening  136 . The opposed cavities G (see FIG. 5) may be sized and configured to allow the elastomeric core  150  to bulge as necessary for insertion without the elastomeric core  150  significantly extending beyond the surfaces  110 A,  110 B so that the elastomeric core  150  does not significantly engage the surfaces surrounding the hole  17 A. 
     Once the latch assembly  100  is fully inserted into the receptacle  17 , the head  140  clears the hole  17 A, thereby allowing the arms  130  to expand apart. The retention edges  132 A of the barbs  132  engage and interlock with the interior surfaces of the receptacle  17  on either side of the hole  17 A. The engagement surfaces of the receptacle  17  may be specially configured cooperative structures. The lead  16  is thereby maintained in contact with the contact  18  (see FIG.  7 ). Preferably, the components of the connector  10  and the receptacle  17  are relatively dimensioned such that the adjacent face of the connector body  12  contacts the receptacle  17 . The body member  110  maintains the torsional rigidity of the latch assembly  100 . 
     In order to remove the latch assembly  100  from the receptacle  17 , the user must apply sufficient force to recompress the arms  130  so that the barbs  132  will clear the hole  17 A. In order to do so, the user must apply sufficient pulling force to overcome the spring force of both the arms  130  and the elastomeric core  150 . The required pulling force will also depend on the selected angle M of the retention edges  132 A. 
     As will be appreciated from the foregoing, the latch assembly  100  may provide increased retention force as compared to a similar type latch assembly not incorporating an elastomeric core. Because the elastomeric core  150  may be relied upon to provide or supplement the physical spring force required to secure the latch assembly  100  to the receptacle  17 , the configuration, construction and materials of the body member  110  may be selected to enhance other properties and functionality. For example, the body member  110  may be formed of a material of relatively low cost and/or exhibiting improved lubricity, wear resistance, stiffness, toughness, abrasion resistance, temperature resistance, dimensional stability, creep resistance, fatigue resistance and/or other desired mechanical properties. The body member  110  may be formed with less material. 
     The amount, configuration and properties of the elastomeric core  150  may be selected to provide the desired amount of spring force. For different applications, it may be desirable to modify the properties of the elastomeric core material to provide more or less retaining spring force while maintaining the same construction for the remainder of the latch assembly  100 . Preferably, the elastomeric core  150  provides at least 20 percent of the total spring force to the latch assembly when the latch assembly is in the intended fully compressed position as shown in FIG. 8, and, more preferably, between about 30 and 80 percent. Preferably, the elastomeric core  150  provides at least 15 Newtons of this spring force, and more preferably between about 15 and 40 Newtons. The total spring force (from both the body member  110  and the elastomeric core  150 ) is preferably between about 50 and 70 Newtons. 
     With reference to FIG. 10, a latch assembly  200  according to a further embodiment of the present invention is shown therein. The latch assembly  200  is identical to the latch assembly  100  except that the base portion  220  and the elastomeric core  150  are differently formed. An end wall  222 , opposed side walls  224 , and arms  230  define a base cavity portion  237 A having corners  227 A and  227 B. A base portion  252  of the elastomeric core  250  is disposed within the cavity portion  237 A and is bonded to the interior surface  220 A. The latch assembly  200  may be preferred over the latch assembly  100  in applications where additional securement between the elastomeric core and the body member is desired. 
     With reference to FIG. 11, a latch assembly  300  according to a further embodiment of the present invention is shown therein. The latch assembly  300  includes a generally U-shaped body member  310  generally corresponding to the body member  110  and having a leading end  304  and a base end  302 . However, the arms  330  of the body member  310  are connected by a connecting portion  131  at the head  340  and have respective free ends  339  at the base portion  320  of the latch assembly  300 . The body member  310  defines a cavity  337  within which an elastomeric core  350  is bonded. The elastomeric core  350  extends from the head  340  to a terminal end  354  adjacent the base portion  320  as shown. 
     The preferred materials and methods for forming the body member  310 , the elastomeric core  350  and the latch assembly  300  are preferably as described above with regard to the latch assembly  100 . The latch assembly  300  may be incorporated into a connector assembly and removably secured to a receptacle in the manner described above with regard to the latch assembly  100 . 
     It will be appreciated from the foregoing descriptions that the latch assemblies  100 ,  200 ,  300  may be modified in various ways. For example, the shapes and dimensions of the body members and the elastomeric cores may be modified. Latch structures other than or in addition to the outwardly extending retention barbs may be provided on one or both of the arms. Moreover, embodiments of the present invention may include various other configurations or features. For example, in accordance with the present invention, each of the embodiments as disclosed in U.S. Pat. No. 5,848,456 and co-pending U.S. patent application Ser. No. 09/528,642 may be provided with an elastomeric core corresponding to the elastomeric core  100 . 
     The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.