Abstract:
A cantilever latch mechanism includes a base and a pair of arms extending from the base. The arms are spaced a distanced apart and selectively positionable between an open orientation wherein an opening is formed between the arms, and a closed orientation where the arms are positioned in a closer relation. Each of the arms may include a jaw extending inwardly into the opening. Preferably, the jaws are positioned on different vertical planes on each arm such that they overlap when the arms are in the closed orientation.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a latch mechanism and, more particularly, to a passive lock latch mechanism having two cantilever arms extending from a common base. 
     BACKGROUND OF THE INVENTION 
     In the telecommunications industry, products continually are getting smaller to meet the demands of consumers. Small product sizes are a valuable attribute because they are easier for the user to handle and more convenient to store when not in use, such as within a briefcase, purse, etc. As a result of the smaller sizes, stronger designs and innovative solutions are necessary for the products to ensure that they do not break or otherwise become damaged in being handled by the consumers. One particularly difficult area is latch mechanisms for securing power and/or communications connectors to wireless communications mobile terminals. Such latching mechanisms should provide sufficient mechanical strength to keep the connector attached while being subject to the physical size restraints of smaller product sizes. 
     Latch designs for connectors typically take either a positive locking approach or a passive locking approach. A positive latching approach requires that the user manually press some portion of the connector mechanism to disengage the latch. In contrast, a passive latching approach allows the user to simply pull on the connector to disengage the latch mechanism. While positive locking approaches tend to be more expensive and consume more space, passive locking schemes are somewhat more prone to failure. While a number of passive locking mechanisms have been proposed, these mechanisms have not proven adequate for all applications, particularly for the small connectors commonly used with wireless communications mobile terminals. 
     Therefore, there is a need for a passive latch mechanism for connectors that provides the mechanical strength required to maintain the mechanism within the corresponding receptacle and still be sized to fit within the physical restraints of the smaller product sizes. 
     SUMMARY OF THE INVENTION 
     The latch mechanism includes two opposing arms that are deformable between an open, spaced-apart orientation and a closed position in which the arms are touching or in proximate relationship to each other. The mechanism returns to the open position when no external forces are applied. When in the open position, the arms provide a spring-like expansion force that opposes deformation into the closed position. Thus, when inserted within a receptacle and deformed towards the closed position, the spring force urges the arms back towards the open position. Upon full insertion, the arms of most embodiments spring outwardly, forcing retention barbs located near the insertion end of the arms outward against a retaining wall in the receptacle, thereby holding the latch mechanism, and thus the connector, in place. Preferably, upon complete insertion into the receptacle, the arms rapidly expand to the open position resulting in an audible “snap” which is heard by the user. 
     In one embodiment of the present invention, the latch mechanism includes an external end having a unitary base, and an insertion end having cantilever arms extending from the base. The arms are selectively positionable between open and closed orientations with an opening extending between the arms in the open orientation. Each of the arms further includes retention barbs extending outward and positioned away from the external end. The arms are preferably positioned such that they are disposed generally parallel to one another so as to form a generally U-shaped body with the base in the open configuration. 
     In some embodiments, the arms may include jaws extending inward from each of the arms. The jaws are positioned on different vertical planes such that they overlap when the arms are in the closed orientation. When the arms are in the open orientation, a channel opening is spaced between the jaws which leads into the opening. The channel opening is closed by the overlapping jaws when the arms are in the closed orientation. 
     The claimed cantilever latch mechanism allows for successful passive latching while providing a robust structure less prone to failure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 perspective view of one embodiment of a latch mechanism constructed in accordance with the present invention; 
     FIG. 2 is a top view of the latch mechanism illustrated in FIG. 1; 
     FIG. 3A is a side view illustrating the latch mechanism in the open orientation prior to insertion into a receptacle; 
     FIG. 3B is a side view illustrating the latch mechanism in the closed orientation during insertion into the receptacle; 
     FIG. 3C is a side view illustrating the latch mechanism in the open orientation after passing through the receptacle; 
     FIG. 4A is a top view of the latch mechanism illustrated in FIG. 3A; 
     FIG. 4B is a top view of the latch mechanism illustrated in FIG. 3B; 
     FIG. 4C is a top view of the latch mechanism illustrated in FIG. 3C; 
     FIG. 5 is a perspective view of an alternative embodiment of a latch mechanism of the present invention; 
     FIG. 6 is a perspective view of an alternative embodiment of a latch mechanism; 
     FIG. 7A is a perspective view of an another alternative embodiment of a latch mechanism; and 
     FIG. 7B is a side view illustrating the latch mechanism of FIG. 7A in the closed position extending around an object. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings in general and FIG. 1 in particular, it will be understood that the illustrations are for the purpose of describing a preferred embodiment of the invention and are not intended to limit the invention thereto. As best illustrated in FIG. 1, the cantilever latch mechanism, generally designated  10 , is shown constructed according to the present invention. The latch mechanism  10  includes a base  20  from which two cantilever arms  30  extend. The latch mechanism  10  mounts within a connector  90  from which the arms  30  extend for mating with a receptacle  100 . The latch mechanism  10  may be a substitute for the device of U.S. Pat. No. 5,848,456, which is incorporated herein by reference. 
     The first end of the latch mechanism  10  includes a base  20  as illustrated in FIG. 2 that extends from a tail  22  to a mediate portion  24  and having a length L 1 . Feet  26  may extend from the base  20  and function as keys to properly orient the mechanism  10  within the connector  90 . The specific configuration of the feet  26  may vary depending upon the specific demands of the latch mechanism  10  and connector  90 . 
     The arms  30  extend from the base  20  and, at least in the open position, are spaced a distance apart forming an opening  28  therebetween. Arms  30  extend between the base  20  and an insertion edge  44  and have a length as illustrated by L 2  in FIG.  2 . Retention barbs  42  extend outward from each arm  30  for contacting the receptacle  100  during insertion and maintaining the latch mechanism  10  in an attached position as will be discussed in more detail below. A retraction angle e is formed between a retention barb edge  46  and the insertion axis I. The retraction angle may vary depending upon the desired amount of force required to remove the mechanism  10  from the receptacle  100 , such as between 100° and 130°. In one embodiment, the retraction angle is approximately 117°. 
     In the embodiment shown in FIG. 1, a jaw  45  extends inward from each arm  30  positioned near the insertion end and opposite the base  20 . The jaws  45  extend inward towards the opening  28 , and help define a channel entry  49  as illustrated in FIG.  2 . Preferably, the channel entry  49  is small to shield the latch mechanism  10  from being incorrectly positioned within the receptacle  100  and from otherwise accidentally catching on objects. The jaws  42  include an angled lead-in edge  43  that extends into an insertion edge  44 . The lead-in angle between the lead-in edge  43  and a line normal to the insertion axis I may vary depending upon the specific circumstances in which the latch mechanism  10  will be used. In one embodiment, the lead-in angle is about 30°. Preferably, the insertion edges  44  of the jaws  45  are also angled, but at a shallower angle, to also aid in deflecting objects and preventing them from inadvertently entering into the opening  28  via the channel entry  49 . 
     As best illustrated in FIG. 1, the jaws  45  are preferably offset and located on different vertical planes to allow for the arms  30  be moved between open and closed orientations. In the closed orientation (e.g., with the arms  30  pressed together) the jaws  45  of the FIG. 1 embodiment overlap, thereby eliminating the channel entry  49 . The range of motion of the arms  30  may vary depending on the desired outcome, and may deflect to a maximum extent such that each of the jaw edges  41  contacts the opposing arm edge  48 . In the open orientation, the jaws  45  may be spaced a distance apart, or the jaws  45  may overlap in the open position such that there is no channel entry  49 . 
     The arms  30  may have an asymmetrical outer shape or so called key shape in order to prevent insertion in the wrong position in the receptacle  100  which is correspondingly asymmetrically profiled. The asymmetrical profiling is achieved by a substantially right-angle keyway  50  positioned on one or both sides of the arms  30  as illustrated in FIG.  1 . Thus, the proper alignment of the latch mechanism  10  within the connector  90  may be aided by the feet  26  and the height h, while the proper alignment of the latch mechanism  10  in the receptacle  100  may be aided by the presence of the keyway  50 . 
     The latch mechanism  10  should be constructed of a rigid or semi-rigid elastic polymer material that is deformable so as to allow for the arms  30  to be selectively positionable between the open and closed orientations. In one embodiment, the mechanism  10  is constructed of materials including Stanyl TW341, and Ultem 1110F. The latch mechanism  10  normally assumes the open orientation when no external forces are applied. The resiliency of the material when the cantilevered arms  30  are deformed from the open orientation creates the spring force illustrated by arrow  9  in FIG.  2 . When the arms  30  are deformed from the open orientation, the spring force urges the arms  30  towards the open position and helps maintain the latch mechanism  10  in attachment with the receptacle  100 . The amount of spring force may be affected by the material of the latch mechanism  10 , or the length of the arms  30 . In one embodiment, the spring force is at least about 35 Newtons. 
     FIGS. 3A-3C, and  4 A- 4 C illustrate the insertion process of the latch mechanism  10  into the receptacle  100 . Within this embodiment, the latch mechanism  10  has already been mounted within the connector  90  such that the arms  30  extend outward from the connector  90 . FIGS. 3A and 4A illustrate the latch mechanism  10  being aligned with a receptacle opening  102  in the receptacle  100  such that the lead-in edge  43  is positioned near a receptacle front edge  106  to guide the mechanism  10  into the opening. The width of the opening W is less than the width of the retention arms in the open position such that an insertion force into the receptacle illustrated by arrow  110  is necessary for inserting the mechanism  10 . As illustrated in FIG. 4A, electrical leads  70  may extend from the connector  90 . 
     FIGS. 3B and 4B illustrate the connector  90  with latch mechanism  10  partially inserted into the receptacle  100 . The retention barbs  42  contact the receptacle edges as the mechanism  100  slides through the opening  102 . The opening  28  is reduced as the arms  30  are pinched together to fit within the receptacle opening  102  and the channel entry  49  is eliminated. While it is typical for both arms  30   a ,  30   b  to flex during insertion, it may be that one of the arms  30  remains stationary as the latch mechanism  10  is moved between the open and closed orientations. FIG. 4B illustrates the edge of the jaws  45  extending partly through the receptacle  100  and through aperture  112  within the receptacle. 
     FIGS. 3C and 4C illustrate the connector  90  with latch mechanism  10  fully inserted into receptacle  100 . The arms  30  extend through the opening  102  such that the retention barbs  42  extend beyond the receptacle edges (retention wall)  106 . The arms  30  expand apart to the open orientation such that the opening  28  is increased, reforming the channel entry  49 . Alternatively, the width W of the opening  102  may be less than the width of the arms  30   a ,  30   b  in the open orientation, therefore the arms  30  are positioned between the open and closed orientations. The spring force of the arms  30  illustrated by arrow  9  in FIG. 2 maintains the mechanism  10  within the opening  102 . Upon full insertion, preferably an audible “snap” as well as a positive seating of the connector  90  into position occurs when the retention barbs  42  extend beyond the receptacle  102  and the arms  30  expand to contact the opening edges. As illustrated in FIG. 4C, the connector neck  90  contacts the receptacle  100  and the electrical leads  70  are firmly connected with their counterparts on the receptacle  100 . 
     Removal of the connector  90  and latch mechanism  10  is obtained in a passive manner by pulling the connector  90 , and therefore the associated latch mechanism  10 , away from the receptacle  100  in the direction illustrated by arrow  120  in FIGS. 3C and 4C. It is not necessary to grasp or otherwise pinch the arms  30  to remove the latch mechanism  10  for removal. 
     FIG. 5 illustrates one alternative design having a base  220  with outwardly extending arms  230  having an opening  228  therebetween. The insertion end includes substantially linear jaws  245  with extension wings  242 . This embodiment does not feature a minimized channel entry  49  or jaws  45  as that disclosed in the embodiment of FIG.  1 . The spacing of the arms  230  provides for positioning between an opening position as illustrated in FIG. 5 with the arms  230  spaced a distance apart with opening  228  between, and a closed position in which the arms  230  contact or are in proximity with a reduced opening. 
     FIG. 6 illustrates a latch mechanism  300  having arms  330   a ,  330   b  extending from the base  320  in offset vertical and horizontal planes. A first arm  330   a  is positioned along a first horizontal base edge and a second arm  330   b  is positioned along a second horizontal base edge. Additionally, the first arm  330   a  is positioned along a first vertical base edge and the second arm  330   b  is positioned along a second vertical base edge. An opening  328  is formed between the arms  330  in the open orientation. Retention barbs  342  extend outward from each of the arms and includes lead-in edges  343  for insertion into the receptacle  100 . 
     FIGS. 7A and 7B illustrate another alternative embodiment in which the latch mechanism  400  attaches about an object  500 , such as a lateral bar disposed in the opening  102  of receptacle  100 , for maintaining proper positioning of the connector  90 . The mechanism  400  includes a base  420  and arms  430  extending therefrom. A jaw  442  with a lead-in angle  443  extends inward from each arm  430 . An opening  428  formed between the arms  430  is sized for containing the object  500 . In a closed orientation as illustrated in FIGS. 7A and 7B, the jaws  442  are positioned proximate to each other. The open orientation is obtained by forcing the lead-in angles  443  against the object  500  such that the arms  430  are forced apart a distance for the object  500  to fit into the opening  428 . Once the object is within the opening  428 , the arms  430  return to the closed position as illustrated in FIG.  7 B. Preferably, the jaws  442  have the same width as the arms  430 . 
     The present invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.