Patent Abstract:
The present invention is a pawl latch which is adapted to be mounted to a first member, such as a closure panel of drawer face plate for releasably retaining the closure panel against an enclosure. Such drawer is suitable for implementing an electronic module which plugs into the backplane of the enclosure. The latch has spring-assisted engagement and disengagement of its pawl with the edge of an enclosure opening against which the pawl operates. This results in spring-assisted inject and eject functions for connecting and disconnecting any associate backplane connection. The latch is low profile with a narrow footprint and has an EMI and ESD event preventive coating on the surface of the housing and appropriate components thereof. A pull handle is substantially flush with the outside face of the latch housing and cooperates with a button spring activator member, when the handle is in the closed position.

Full Description:
RELATED APPLICATIONS  
       [0001]    The subject matter of this application relates to the invention disclosed in, and claims benefit of, U.S. Provisional Application No. 60/290,462, titled, Pawl Inject/Eject Latch, filed Jun. 1, 2001, and U.S. Provisional Application No. 60/371,527, titled, Sliding Panel Latch, filed Apr. 9, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention relates generally to a latch for releasably securing a first member relative to a second member. The first member moves at least partially relative to the second member resulting in a secured position.  
           [0003]    Latches are used to releasably secure panels, covers, doors, drawers, electronic modules, glove boxes, and the like to other generally larger structures, such as housings, compartments, doorframes, panel fronts, frames, racks and other structures. These latches are mounted by various means, including screws, rivets, blade fasteners, spring clips, stake fasteners and other structures. Each latch generally includes a housing portion; and includes another portion, such as a lever, pull, button, stud, catch plate or other such structural member. The housing portion performs the function of the second, non-moving member, while the other portion performs the function of the first, moving member. Each latch is mounted so that the housing portion is fixed to the generally larger structure, i.e., the doorframe, panel front, frame, rack, and other structure.  
           [0004]    When latches are used hold electronic and power modules and circuit breakers in power and distribution panels, or in communications panels, the operation of the latch and its ability to be installed and/or removed without tools or with unsophisticated tools becomes important. Moreover, it becomes desirable that the latch has a flush outer appearance or is nearly flush with the panel face when closed. These features are also desirable when latches are used to secure and to pull-out electronic module drawers, or power module drawers, in respective communications panels or power distribution panels, such as those found in communications and power distribution centers and/or substations and transmission nodes.  
           [0005]    Often the conventional method for mounting electronics and /or opto-electronic modules in enclosures, i.e., housings and panels includes a printed circuit board mounted to a metal face plate (panel), or a metal drawer or tray which carries modules. In the past, these modules commonly were slid into an enclosure guided by card guides, ball slides, or some other form of linear guide. In each situation, there is an electrical connector on the back of the printed circuit board or tray which engages a mating (complementary) connector mounted inside the enclosure (the enclosure back plane).  
           [0006]    There have been various designs for latches and connectors which either include spring biasing or deformable members for quick mounting. Atkinson, U.S. Pat. No. 2,720,772, shows a bag or suitcase latch with a pop-up movement. Aylott, U.S. Pat. No. 3,896,698, shows a quick release fastener, which has button activation and spring biasing. Vogel, U.S. Pat. No. 3,957,225, shows a tape cartridge latching mechanism with a spring biased release. Mahan, et al., U.S. Pat. No. 4,379,579, show a locking and ejecting hook assembly in which a releasable latch includes a spring and cam operated ejection. Nardella, et al., U.S. Pat. No. 4,618,118, show a molded latch housing with a flanged surface installed in a rectangular cutout. A spring connected the hook at the forward end of the latch keeps the latch normally in the locked position. Shimamura, et al., U.S. Pat. No. 4,724,310, shows a spring biased integrated circuit card drawer and carrier. Rudoy, U.S. Pat. No. 4,973,255, shows torque-type locking and ejecting mechanism for a PC cable connector. Rogers, et al., U.S. Pat. No. 5,048,877, show an automobile pop-up hood latch with a cable release and a spring biased open position. Kameyama, U.S. Pat. No. 5,279,509, shows a cable connector with deformable side stakes which act as a quick engagement mount. Once in the mounted position the stakes return to their original position to lock the mounting. Kohl et al., U.S. Pat. No. 5,575,163, show a removable attachment structure for a car radio, including a deformable spring lock member. Ellis, U.S. Pat. No. 5,620,213, shows a low profile pull-type latch used as a window lock. Wytcherley, et al., U.S. Pat. No. 6,203,076, show a fold down handle for a panel with controlled pushing and pulling action. Kuroda et al., U.S. Pat. No. 6,280,206, show a high voltage cable connector with deformable socket contacts which act as a locking mechanism once the two members of the connector are joined.  
           [0007]    Previous latches have presented problems that make them difficult or impractical to use to mount and hold removable electronic modules or communications/ power distribution drawers. Specifically, these latches do not provide an adequate user (operator) finger grasping surface to pull open. The force necessary to open these latches and thereby disengage an electrical connector is substantial enough to cause discomfort to the fingers, when a user attempted to release the latch, i.e., to open the pull member. Furthermore, the prior electronic module latches do not consider electromagnetic interference, nor do they consider shielding against such interference, nor did they provide sufficient restraint during a physical shock.  
           [0008]    It is desirable to provide a latch, which is capable of injecting an attached structure and ejecting that attached structure with user ease, and in retaining the structure secured from jarring loose during a shock or a seismic event.  
           [0009]    It is also desirable to provide a latch, which can be used to secure a circuit board drawer in a communications center panel or a power distribution center panel face of an enclosure within the close tolerances found.  
           [0010]    It is further desirable to provide a latch with a flush or nearly flush face.  
           [0011]    It is even further desirable to provide a latch with a narrow footprint and low profile, with a quick mount and quick remove features without the need for specific tools.  
           [0012]    It is additionally desirable to provide a latch with electromagnetic interference (EMI) shielding, and grounding to prevent electrostatic discharge (ESD) through the latch.  
           [0013]    It is additionally desirable to provide a latch with an easy open feature.  
         SUMMARY OF THE INVENTION  
         [0014]    The objectives of the present invention are realized in a pawl-type, inject-eject latch having a rotatable, deformable wire bail mounting (without tools). This pawl inject-eject latch provides a low profile and narrow footprint configuration, and is essentially capable of being installed and removed without tools. The latch includes an elongate housing member which is installed into a cutout in the face of a panel or face of a drawer. Operating within the housing so as to be accessible from the face is an elongate pull handle which is connected to operate a pawl. This pull handle is spring biased to the open position whereof the spring action and rotation of the pull about one end thereof causes a release of the pawl. A button release frees the pull biasing spring to rotate the pull and operate the pawl.  
           [0015]    A wire bail surrounds the housing, is carried thereon, and rotates from the pull pivot end of the housing during housing insertion and removal from a mating panel (face) cutout. This bail interlocks with portions of the housing to hold the latch housing securely in place against the face onto which it is mounted. The cutout in the face includes “bump-out” type cutouts to provide space for the wire bail to pass when the housing is inserted or removed. The bail is pivoted to extend at right angles (orthogonal) to the face during the removal and insertion of the latch thought the face cutout.  
           [0016]    In its application, the inject-eject pawl latch is mounted to a first member, such as a closure panel for releasably retaining the closure panel against an enclosure. More specifically, this panel forms the face of a drawer-type module usually, including an electronic component carrying circuit board. The latch housing can receive a plurality of pins, wherein the handle and pawl members are mounted for rotational movement. The handle is substantially flush with the housing and is in contact with a button member in the closed position. The button releases the pull handle and results in a spring assisted activation of the opening of the pull handle and the disengagement of the pawl from its engagement with the enclosure. The movement of the handle, button member and pawl member are biased by a central torsion spring whose operation is permitted by the rotation of a release plate. This release plate&#39;s rotation is created by depressing the button. The materials are usually constructed of a metal material but some plastic parts can be used. The housing and appropriate components have s surface coating to reduce or eliminate EMI and ESD effects. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS:  
       [0017]    The features, advantages and operation of the present invention will become readily apparent from a reading of the following description in connection with the accompanying drawings, in which like numerals refer to like elements, and in which:  
         [0018]    [0018]FIG. 1 is perspective view of an enclosure illustrating the relationship of the module, latches and linear guide;  
         [0019]    [0019]FIG. 2 is an exploded view of the preferred embodiment of the latch of the present invention;  
         [0020]    [0020]FIG. 3 is a frontal view of panel and housing receiving cutout for the preferred embodiment of this latch;  
         [0021]    [0021]FIG. 4 is a perspective view of the housing of the preferred embodiment of the latch;  
         [0022]    [0022]FIG. 4A is a left side view of the housing of this first embodiment of the latch;  
         [0023]    [0023]FIG. 4B is a top view the housing of the latch of FIG. 4;  
         [0024]    [0024]FIG. 4C is a bottom view the housing of the latch of FIG. 4;  
         [0025]    [0025]FIG. 4D is a rear view the housing of the latch of FIG. 4;  
         [0026]    [0026]FIG. 4E is a front view the housing of the latch of FIG. 4;  
         [0027]    [0027]FIG. 5 is a perspective view of the pawl member of the first embodiment of the latch of the present invention;  
         [0028]    [0028]FIG. 5A is a side view of the pawl member of the latch of FIG. 5;  
         [0029]    [0029]FIG. 5B is a top view of the pawl member of the latch of FIG. 5;  
         [0030]    [0030]FIG. 5C is a bottom view of the pawl member of the latch of FIG. 5;  
         [0031]    [0031]FIG. 5D is a rear view of the pawl member of the latch of FIG. 5;  
         [0032]    [0032]FIG. 5E is a front view of the pawl member of the latch of FIG. 5;  
         [0033]    [0033]FIG. 6 is a perspective view of the button member of the first embodiment of the latch of the present invention;  
         [0034]    [0034]FIG. 6A is a left side view of the button member of FIG. 6;  
         [0035]    [0035]FIG. 6B is a top view of the button member of FIG. 6;  
         [0036]    [0036]FIG. 6C is a bottom view of the button member of FIG. 6;  
         [0037]    [0037]FIG. 6D is a rear view of the button member of FIG. 6;  
         [0038]    [0038]FIG. 6E is a front view of the button member of FIG. 6;  
         [0039]    [0039]FIG. 7 is a perspective view of the handle of the first embodiment of the latch of the present invention;  
         [0040]    [0040]FIG. 7A is a left side view of the handle of FIG. 7;  
         [0041]    [0041]FIG. 7B is a top view of the handle of FIG. 7;  
         [0042]    [0042]FIG. 7C is a bottom view of the handle of FIG. 7;  
         [0043]    [0043]FIG. 7D is a rear view of the handle of FIG. 7;  
         [0044]    [0044]FIG. 7E is a front view of the handle of FIG. 7;  
         [0045]    [0045]FIG. 8 is a perspective view of the torsion spring of the first embodiment of the latch of the present invention;  
         [0046]    [0046]FIG. 8A is a side view of the torsion spring of FIG. 8;  
         [0047]    [0047]FIG. 8B is a top view of the torsion spring of FIG. 8;  
         [0048]    [0048]FIG. 8C is a bottom view of the torsion spring of FIG. 8;  
         [0049]    [0049]FIG. 8D is a rear view of the torsion spring of FIG. 8;  
         [0050]    [0050]FIG. 8E is a front view of the torsion spring of FIG. 8;  
         [0051]    [0051]FIG. 9 is a perspective view of a first embodiment of the clamp of the first embodiment of the latch of the present invention;  
         [0052]    [0052]FIG. 9A is a side view of the first embodiment of the wire bail clamp of FIG. 9;  
         [0053]    [0053]FIG. 9B is a top view of the clamp of FIG. 9;  
         [0054]    [0054]FIG. 9C is a bottom view of the clamp of FIG. 9;  
         [0055]    [0055]FIG. 9D is a rear view of the clamp of FIG. 9;  
         [0056]    [0056]FIG. 9E is a front view of the clamp of FIG. 9;  
         [0057]    [0057]FIG. 10 is a perspective view of the pin members of the first embodiment of the latch of the present invention;  
         [0058]    [0058]FIG. 10A is a side view of the pin members of FIG. 10;  
         [0059]    [0059]FIG. 10B is a top view of the pin members of FIG. 10;  
         [0060]    [0060]FIG. 10C is a bottom view of the pin members of FIG. 10;  
         [0061]    [0061]FIG. 10D is a rear view of the pin members of FIG. 10;  
         [0062]    [0062]FIG. 10E is a front view of the pin members of FIG. 10;  
         [0063]    [0063]FIG. 11 is a perspective view of the fully assembled latch of the first embodiment of the present invention including the first embodiment of the wire bail clamp;  
         [0064]    [0064]FIG. 11A is a side view of the full assembly of FIG. 11;  
         [0065]    [0065]FIG. 11B is a top view of the full assembly of FIG. 11;  
         [0066]    [0066]FIG. 11C is a bottom view of the full assembly of FIG. 11;  
         [0067]    [0067]FIG. 11D is a rear view of the full assembly of FIG. 11;  
         [0068]    [0068]FIG. 11E is a front view of the full assembly of FIG. 11;  
         [0069]    [0069]FIG. 12 is a perspective view of the first embodiment full assembly illustrating the partial insertion into a prepared panel face;  
         [0070]    [0070]FIG. 13 is a right side view of the first embodiment full assembly illustrating the movement into clamping position of the clamp;  
         [0071]    [0071]FIG. 13A is a right side view of the full assembly of FIG. 13 showing the clamp in the installed locking position;  
         [0072]    [0072]FIG. 14 is a perspective assembly view of the latch and a second embodiment of a cradle mounting attachment being an alternative to the first wire bail clamp;  
         [0073]    [0073]FIG. 15 is a perspective view of the second embodiment cradle mounting attachment structure;  
         [0074]    [0074]FIG. 15A is a side view of the cradle mounting of FIG. 15;  
         [0075]    [0075]FIG. 15B is a top view of the cradle mounting of FIG. 15;  
         [0076]    [0076]FIG. 15C is a bottom view of the cradle mounting of FIG. 15;  
         [0077]    [0077]FIG. 15D is a rear view of the cradle mounting of FIG. 15;  
         [0078]    [0078]FIG. 15E is a front view of the cradle mounting of FIG. 15;  
         [0079]    [0079]FIG. 16 is a top view of a panel face prepared cutout opening for the assembly of the latch and cradle mounting attachment;  
         [0080]    [0080]FIG. 17 is a cross-sectional exploded view of the assembly of the first embodiment of the latch and the first embodiment of the wire bail clamp with the latch handle in the closed position;  
         [0081]    [0081]FIG. 18 is a cross-sectional perspective view of the assembly of FIG. 17 with the latch handle in the half-open position and the pawl engaged prior to ejection;  
         [0082]    [0082]FIG. 19 is a cross-sectional perspective view of the assembly of FIG. 17 with the latch handle in the fully-opened position and the pawl disengaged after ejection;  
         [0083]    [0083]FIG. 20 is a perspective view of a second embodiment of the latch of the present invention fully assembled in the closed position;  
         [0084]    [0084]FIG. 20A is a right side view of the second embodiment of the latch of FIG. 20;  
         [0085]    [0085]FIG. 20B is a top view of the second embodiment of the latch of FIG. 20;  
         [0086]    [0086]FIG. 20C is a bottom view of the second embodiment of the latch of FIG. 20;  
         [0087]    [0087]FIG. 20D is a rear view of the second embodiment of the latch of FIG. 20;  
         [0088]    [0088]FIG. 20E is a front view the second embodiment of the latch of FIG. 20;  
         [0089]    [0089]FIG. 21 is a perspective view of the second embodiment of the latch in the open position;  
         [0090]    [0090]FIG. 21A is a right side view of the second embodiment of the latch of FIG. 21;  
         [0091]    [0091]FIG. 21B is a top view of the second embodiment of the latch of FIG. 21;  
         [0092]    [0092]FIG. 21C is a bottom view of the second embodiment of the latch of FIG. 21;  
         [0093]    [0093]FIG. 21D is a rear view of the second embodiment of the latch of FIG. 21;  
         [0094]    [0094]FIG. 21E is a front view the second embodiment of the latch of FIG. 21;  
         [0095]    [0095]FIG. 22 is an exploded view of the elements of the second embodiment of the latch;  
         [0096]    [0096]FIG. 23 is a perspective view of the housing of the second embodiment of the latch of FIGS.  21 - 22 ;  
         [0097]    [0097]FIG. 23A is a right side view of the housing of FIG. 23;  
         [0098]    [0098]FIG. 24 is a perspective view of the button member of the second embodiment of the latch;  
         [0099]    [0099]FIG. 24A is a right side view of the button member of FIG. 24;  
         [0100]    [0100]FIG. 25 is a perspective view of the mounting clip of the second embodiment of the latch;  
         [0101]    [0101]FIG. 25A is a right side view of the mounting clip of FIG. 25;  
         [0102]    [0102]FIG. 26 is a perspective view of the handle of the second embodiment of the latch;  
         [0103]    [0103]FIG. 26A is a right side view of the handle of FIG. 26;  
         [0104]    [0104]FIG. 26B is a top view of the handle of the second embodiment of the latch;  
         [0105]    [0105]FIG. 26C is a bottom view of the handle of FIG. 26;  
         [0106]    [0106]FIG. 26D is a rear view of the handle of FIG. 26;  
         [0107]    [0107]FIG. 26E is a front view of the handle of FIG. 26;  
         [0108]    [0108]FIG. 27 is a perspective view of the flat spring of the second embodiment of the latch;  
         [0109]    [0109]FIG. 27A is a right side view of the flat spring of FIG. 27;  
         [0110]    [0110]FIG. 28 is a perspective view of the torsion spring of the second embodiment of the latch;  
         [0111]    [0111]FIG. 28A is a right side view of the torsion spring of FIG. 28;  
         [0112]    [0112]FIG. 29A is a left side assembly view of the second embodiment of the latch and flat spring when being installed into a panel face;  
         [0113]    [0113]FIG. 29B is a left side view of the assembly of FIG. 29A installed into a panel face but prior to the insertion of the mounting clip;  
         [0114]    [0114]FIG. 29C is a left side view of the assembly of FIG. 29B with the mounting clip inserted;  
         [0115]    [0115]FIG. 30 is a left side view of the assembly of the second embodiment of the latch and flat spring with the pawl member engaging the edge of the enclosure frame;  
         [0116]    [0116]FIG. 31 is a perspective cross-sectional exploded view of the elements of the second embodiment of the latch;  
         [0117]    [0117]FIG. 32 is a perspective cross-sectional view of the second embodiment of the latch assembled and in the closed position;  
         [0118]    [0118]FIG. 33 is a perspective cross-sectional view of the second embodiment of the latch assembled and in the open position;  
         [0119]    [0119]FIG. 34 is a cross-section of the torsion spring of the second embodiment during activation of the latch with a portion of the torsion spring in the groove of the handle and the button member removed;  
         [0120]    [0120]FIG. 35 is a perspective view of a third embodiment of the latch of the present invention in the closed position;  
         [0121]    [0121]FIG. 35A is a right side view of the third embodiment of the latch of FIG. 35;  
         [0122]    [0122]FIG. 35B is a top view of the third embodiment of the latch of FIG. 35;  
         [0123]    [0123]FIG. 35C is a bottom view of the third embodiment of the latch of FIG. 35;  
         [0124]    [0124]FIG. 35D is a rear view of the third embodiment of the latch of FIG. 35;  
         [0125]    [0125]FIG. 35E is a front view the third embodiment of the latch of FIG. 35;  
         [0126]    [0126]FIG. 36 is a perspective exploded view of the elements of the third embodiment of the latch;  
         [0127]    [0127]FIG. 37 is a perspective cross-sectional view of the assembled third embodiment of the latch of FIG. 36 in the closed engagement position;  
         [0128]    [0128]FIG. 38 is a perspective cross-sectional view of the third embodiment of the latch of FIG. 36 in the partially open first position prior to ejection;  
         [0129]    [0129]FIG. 39 is a perspective cross-sectional view of the third embodiment of the latch of FIG. 36 in more open second position beginning ejection;  
         [0130]    [0130]FIG. 40 is a perspective cross-sectional view of the third embodiment of the latch of FIG. 36 in a even more open third position further during ejection;  
         [0131]    [0131]FIG. 41 is a perspective cross-sectional view of the third embodiment of the latch of FIG. 36 in the fully open position after ejection;  
         [0132]    [0132]FIG. 42 is a cross-sectional assembly view of a fourth embodiment of the latch of the present invention in the closed position;  
         [0133]    FIGS.  43 - 46  are perspective, side, end and top views, respectively, of a third retainer being a second embodiment of the wire bail clamp for the latch;  
         [0134]    FIGS.  47 - 50  are perspective, side, end and top views, respectively, of the mating housing carrying receiving openings for use with the second embodiment wire bail clamp of FIGS.  43 - 46 ;  
         [0135]    FIGS.  51 - 54  are perspective, side, end and top views, respectively, of the assembled mating housing and second embodiment wire bail clamp of FIGS.  43 - 50 ;  
         [0136]    [0136]FIG. 55 is a perspective partial view assembly of the housing of the first embodiment latch with the first embodiment wire bail clamp partially inserted into the panel cutout;  
         [0137]    [0137]FIG. 56 shows the assembly of FIG. 55 with the first latch housing and first wire bail fully inserted into the panel cutout;  
         [0138]    [0138]FIG. 57 shows the inserted assembly of FIG. 56 with the wire bail rotated into the clamping position;  
         [0139]    [0139]FIG. 58 is a perspective partial view assembly of the second embodiment of the wire bail clamp with its mating housing partially inserted into the panel cutout;  
         [0140]    [0140]FIG. 59 shows the assembly of FIG. 58 with the mating housing and second embodiment wire bail fully inserted into the panel cutout; and  
         [0141]    [0141]FIG. 60 shows the inserted assembly of FIG. 59 with the second embodiment wire bail rotated into the clamping position with its mating housing. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0142]    This present invention provides a pawl inject-eject latch assembly with a quick release mounting clamp. The latch pawl movement is spring assisted to perform panel or drawer inject and eject operation which in turn performs associated electrical connector inject and eject movement. The latch assembly has a low profile flush mounting and is intended for use for retaining electronics and/or opto-electronics modules in larger enclosures. These modules typically take the form of printed circuit boards mounted to a metal face plate or panel member or may take the form of a metal drawer or tray which carries electronics, power transmission components, switch gear, routing circuitry, or other electrical and electronic units. The modules each commonly slide into the larger enclosure guided by card guides, ball slides, or some other form of linear guide. In all cases there is an electrical or electronic signal connector on the back of the printed circuit board or tray, which engages a complementary (mating) connector mounted inside the larger enclosure (usually the backplane). The present latch may be used in pairs for each drawer or panel plate, with each latch aligning with the linear guides on each side of a module.  
         [0143]    The latch mounts to the panel (face plate of a drawer) with its pawl capable of engaging the exposed edge of the larger enclosure opening for the drawer. The user (operator) would operate a pair of latches simultaneously to open a drawer and minimize any possible damage to the rear mounted connector.  
         [0144]    The pawl inject-eject latch of the present invention thereby has the ability of injecting the module, of ejecting the module, and of retaining the module even through a severe jarring, as in a seismic event. The latch is coated for EMI (electromagnetic interference) shielding and for grounding to prevent ESD (electrostatic discharge) through the latch.  
         [0145]    [0145]FIG. 1 shows an enclosure  10  wherein a plurality of modules  20  are stored. These modules  20  are each a printed circuit board mounted to a face plate or panel  30 . The modules  20  slide into the enclosure  10  by means of a linear guide  40 . The latch  100  is installed, usually in pairs, within the panel  30  and are aligned inside of the linear guides  40 .  
         [0146]    In FIGS. 2 and 3 the preferred embodiment of the latch is shown prior to installation having individual elements including a housing  102 , a pawl member  104 , a button member  106 , a handle  108 , a torsion spring  110 , a clamp  112  and pin members  114 ,  116  and  118 . The prepared panel  30  is shown having a top side  32 A and bottom side  32 B.  
         [0147]    [0147]FIGS. 4 through 4E show the housing  102  having a front side  120 , back side  122 , right side  124 , left side  126 , top portion  128 , bottom portion  130  and a flange  132 . A ledge  132 A is located under the flange  132  so as to provide conductivity between the housing  102  and the panel  30  to prevent EMI and ESD. The housing  102  has a recessed area  130 A on the bottom side  130  for storage of the handle  108 . The front side  120  has an aperture  134  which allows for the positioning of the pawl member  104  when the latch  100  is assembled. The right side  124  and left side  126  of the housing  102  have corresponding aperture pairs forward  136 A, 136 B, central  138 A, 138 B and longitudinal  140 A, 140 B which allow for the movement of the clamp  112 , pawl member  104 , button member  106  and handle  102 , as discussed further below. The exterior of the housing  102 A has corresponding ramped elements  142 A, 142 B on the right side  124  and left side  126 , respectively, which lock the clamp  112  to secure the latch  100  to the panel  30 . The interior of the housing  102 B has button member mounts  144 A, 144 B having a rounded central area  146 A, 146 B between a substantially horizontal forward stop  148 A, 148 B and rear stop 150 A, 150 B. Undercuts  151 A,  151 B are located on the front side  120  below the flange  132  for securing the housing  102  to the panel  30 .  
         [0148]    Referring to FIGS. 5 through 5E, the pawl member  104  is shown having a double pawl front portion comprising a primary  152 A and secondary  152 B finger. The central aperture  154  and longitudinal aperture  156  align with the forward aperture  136 A,  136 B and longitudinal aperture  140 A,  140 B of the housing  102 . The top portion  158  has an indented section  159  which permits the handle  108  to lay flush when in the closed position and to avoid contact during activation. The top portion  158  and bottom portion  160  are parallel to each other and substantially perpendicular to a rear portion  162 .  
         [0149]    In FIGS. 6 through 6E, the button member  106  is shown having a body portion  164 . A raised central activation portion  168  with a lip member  166  extending forward and a rearward cam member  170  extend radial from the body portion  164 . A forward cam member  171  extends from the central body portion  164 . Rotational movement of the button member  106  is limited by the contact of the forward cam member  171  with the forward stop member  148 A,  148 B of the housing  102 . The rear cam member fills any gap made between the handle  108  and button member  106  to negate the possibility of any foreign matter falling into the housing  102 . An aperture  172  extending through the body portion  164  aligns with the central aperture  138 A and  138 B of the housing  102 .  
         [0150]    [0150]FIGS. 7 through 7E show the handle member  108  comprises a central body portion 174  having a flush top surface  174 A and a ramped bottom surface  174 B which contours the shape of the torsion spring  110 . The most posterior section  176  of the central body portion is tapered to be flush with the housing  102 . In addition, the posterior section  176  acts as a tab member for further ease of use by the user (operator 0 . The central body portion  174  is continuous with forward body section  178  which is forked at its internal midsection wherein the pawl member  104  aligns. The exterior portions of the forward body portion form a pair of surfaces  178 A, 178 B. Each surface of the exterior portion  178 A, 178 B of the forward body portion  178  have a top aperture  180 A,  181 A and bottom aperture  180 B,  181 B vertically arranged therein. The top apertures  180 A,  181 A are aligned with the forward housing apertures  136 A and  136 B and the pawl aperture  154  and the bottom aperture  180 B,  181 B is aligned with the longitudinal apertures  140 A,  140 B, 156  of the housing  102  and of the pawl member  104 . A rear body section  182  extends from the top portion  174  and is tapered for grasping by the operator finger during activation (discussed below). The central body portion  174  is interrupted midway by an aperture  184  which allows the access to the button member  106 . The bottom surface  174 A of the body portion  174  extends into the aperture  184  so as to form a lip portion  186 .  
         [0151]    In FIGS. 8 through 8E, the torsion spring  110  is shown having a closed curved end  188  and an open end  190  with contact points  190 A,  190 B. The coiled section  191  is traversed by the forward pin member  114 , so as to avoid movement and reduce contact with other elements of the latch  100 .  
         [0152]    Referring to FIGS. 9 through 9E, the clamp  112  is shown having attachment rotation ends  12 A, 112 B. Contact points  192 A,  192 AA,  192 B,  192 BB are evenly distributed on each side of the wire bail clamp  112 .  
         [0153]    In FIGS. 10 through 10E, a pin member  114  is illustrated which is identical to the other pin members  116 , 118  used in the invention. The pin members are distributed in the forward  114 , lower  116  and centrally  118 . The forward pin member  114  is used for rotation of the pawl member  104  and handle  108  and traverses the forward aperture  136 A, 136 B. The lower pin member is used for “horizontal” movement of the pawl member  104  and handle  108  and traverses the longitudinal aperture  140 A, 140 B of the housing  102 . The central pin member  118  is used for rotational movement of the button member  106  and traverses the central aperture  138 A,  138 B of the housing  102 .  
         [0154]    Referring now to FIGS. 11 through 11E, the fully assembled latch  100  is substantially flush on the top wherein only the button member  106  is slightly raised.  
         [0155]    In FIGS. 12, 13, and  13 A, installation of the preferred embodiment of the latch  100  to the panel  30  is illustrated using the multiple point clamp  112 . The ends  112 A,  112 B of the clamp  112  fit loosely inside the ends of the forward pin  114  which acts as a fulcrum for the handle  108  and pawl member  104 . This allows the clamp  112  to rotate about the forward pin  114 .  
         [0156]    Mounting of the latch  100  in the panel  30  is accomplished by guiding the latch  100  through the cutout  34  in the panel  30 . The cutout  34  is notched in five places to provide clearance for the clamp  112 , ramps  142 A, 142 B and pawl  104 . These notches are bump-outs of the opening created by the cutout  34 .  
         [0157]    As the latch  100  passes through the panel  30 , the wire bail-type clamp  112  is rotated so as to straddle the latch housing  102 . The forward most two contact points of the clamp  192 A,  192 B will bear against the bottom side of the panel  32 B pulling the latch housing  102  tight against the panel  30 . Rotating the bail clamp  112  still further rides the clamp  112  up and over the tapered projecting shoulders or projecting ramps  142 A, 142 B, one on each side of the housing  102 , thus slightly expanding or spreading the side legs of the bail clamp  112  to ride over the ramps  142 A,  142 B, and then rest on the flat abutment portion  143 A,  143 B of each respective ramp  142 A, 142 B. The bail  112  is therefore trapped and the housing  102  is fixed into locked position against the panel bottom side  32 B.  
         [0158]    Simultaneously, the remainder of the contact points  192 AA,  192 BB are secured against the bottom of the panel  32 B. The multiple contact points of the clamp  192 A,  192 AA,  192 B,  192 BB are used to distribute tension load. In FIGS. 14, 15,  15 A through  15 E, and  16 , a second embodiment of the mounting is illustrated, wherein a cradle-type bracket  212  is attached to the housing  102  by any of a variety of attachment means, including self-tapping screws. The attachment screw extends through an aperture  214  in the cradle bracket  212  and a receiving hole in the housing  131 . A prepared panel  230  is shown in FIG. 16 to accommodate the bracket  212 . The bracket ends  216 A, 216 B contact the bottom side of the panel  232 B, wherein the panel  230  is held in place by the bracket  212 , ramps  142 A, 142 B and the undercuts  151 A, 151 B. The cutout  234  has 3 notches  234 A,  234 B and  234 C, with the first to on opposite sides and the third at one end.  
         [0159]    In FIGS. 17 through 19, the activation of the latch  100  and ejection of the module  20  is accomplished by pushing the button member  106  rearward wherein it rotates downwardly around the central pin member  118  which traverses the button aperture  172  and central housing apertures  138 A,  138 B. As the button  106  is moved rearward its pivotal connection also forces it downward. Specifically, the button member  106  rotates on the rounded central portion  146 A,  146 B of the button mounts  144 A,  144 B, which disengages the lip portion  106 A of the button  106  from the lip portion  186  of the pull handle  108 . Rotation is limited by contact of the forward cam member  171  of the button member  106  with the forward stop  148 A, 148 B of the housing  102 . This action is biased by the torsion spring  110 , which contacts the forward cam member  171  with ends  190 A, 190 B of the open side  190 .  
         [0160]    In FIG. 18, the pull handle  108  moves to a first position driven by contact on its bottom surface  174 A with closed end the torsion spring  188 . The movement to the first position is limited to the distance the lower pin member  116  which traverses the longitudinal pawl member aperture  156 , bottom handle aperture  180 B,  181 B and longitudinal housing aperture  140 A, 140 B is permitted to move horizontally. The handle  108  in the first position allows the user (operator) finger to grasp rear body portion  182  of the pull handle  108 .  
         [0161]    Further rotation of the handle  108  beyond that of the first position, requires the operator to forcibly move the handle  108  through its intended range of motion. This rotational movement of the handle  108  around the forward pin member  114  drives the pawl member  104  rearward disengaging the enclosure  10 . As this motion retracts the pawl member  104  rearward, the secondary finger  152 B of the pawl member  104  bears against the enclosure face  12  to force the latch  100  and module  20  out of the enclosure  10  enough to disengage the electrical components at the back of the module  20 . The rear handle area  182  of the pull handle  108  can be used to pull the module  20  out of the enclosure  10 .  
         [0162]    To insert a module  20  into the enclosure  10 , the operator pushes the panel  30  sliding the module  20  into the enclosure  10  until the secondary finger  152 B of the pawl  104  on each latch comes to rest against the from face of the enclosure  12 . This movement does not affect the pawl member  104  because the lower pin member  116  in the longitudinal apertures  140 A, 140 B, 156  of the pawl  104  and housing  102  are free to move within the longitudinal aperture. The operator then pushes the handle  108  of the latch  100  back into their housing  102  until the lip of the button member  166  snaps over the lip of the handle  186  locking the handle  108 . The movement of the handle  108  moves the pawl member in unison thus driving the primary finger  152 A of the pawl member  104  around to then bear against the back of the edge of the enclosure  14  face opening, thus pulling the latch  100  and module  20  into the enclosure  10 .  
         [0163]    Another embodiment of the latch in accordance with the present invention is illustrated in FIGS. 20 through 33. The latch  500  in this second embodiment of the invention is similar in both structure and function to many of the features already described in detail with respect to the latch  100 , and for this reason, only the differences in the latch  500  from the latch  100  will be described herein.  
         [0164]    In FIGS. 20, 20A through  20 E,  21 ,  21 A through  21 E, and  22 , the second embodiment of the latch  500  is illustrated in the open and closed positions. The latch  500  is designed to be used where a single “finger” pawl member is needed to engage a slot edge of a segmented frame. The latch  500  includes a housing  502 , a pawl member  504 , a button member  506 , a handle  508 , a torsion spring  510 , a flat spring  511 , a mounting clip  513  and pin members  514 , and  518 .  
         [0165]    In FIGS. 23 and 23A, the latch  500  is shown having a housing  502  with a flange  532  and a rear attachment spring mount  530 A. A ledge  532 A is located under the flange  532  so as to provide conductivity between the housing  502  and the panel  630  so as to prevent EMI and ESD. The spring mount  530 A on the backside  522  for attachment of the flat spring  511 . On the interior of the housing  502 A are ribs  544 A,  544 B which stop the rotation of the button means  506 . A mounting clip aperture  555  traverses the flange  532  above the front side  520  of the housing  502 .  
         [0166]    Referring to FIGS. 24 and 24A, a button member  506  is similar to the button member  106  except for the design of the body portion  564 . The body portion  564  comprises a mounting bar  565  for attachment of the torsion spring  510  so as to bias the activation motion of the button member  506 .  
         [0167]    Shown in FIGS. 25 and 25A, a mounting clip  513  has a flat top surface  513 A integral with a body portion  513 B which has ribbed U-shaped segments  513 C,  513 D. The ribbed U-shaped segments  513 C, 513 D are deformed during installation of the mounting clip  513  through the flange  532 . This deformation is a spreading of the U shape. The mounting clip  513  operates as a lock device to secure the housing  502  to the panel  530 .  
         [0168]    As shown in FIGS. 26 and 26A through  26 E, the handle  508  has a body portion  574  with a flat top surface  574 A and a contoured bottom surface  574 B which converge forward to form a pawl  504 . The bottom surface of the handle  574 B has a groove  575  wherein the torsion spring  510  is aligned to retard movement when the latch  500  is assembled. As in the first embodiment, the body portion  574  is interrupted midway by a top aperture  584  which allows access to the button member  506 . The bottom surface  574 A of the body portion  574  extends into the aperture  584  so as to form a lip portion  586 .  
         [0169]    As shown in FIGS. 27 and 27A, the continuous flat spring  511  has a hairpin coil  511 A and a obtuse coil  511 B. The function of the hairpin coil  511 A is for mounting on the spring mount  530 A wherein the function of the obtuse coil  511 B is biasing the movement of the housing  502  when in the panel as will be discussed further below.  
         [0170]    [0170]FIGS. 28 and 28A show the torsion spring has a closed end  588  which forms a camming portion  588 A and an open end  590  wherein each end  590 A,  590 B forms a hook for attachment to the mount bar  565  of the button member  506 .  
         [0171]    Referring to FIGS. 29A through 29C and  30 , the latch  500  installs into a rectangular cutout in a panel  630 . As shown in FIG. 29A, the latch  500  is installed by nosing it (direction shown by the arrow) into the rectangular cutout to engage the undercuts  551 A, 551 B at the pawl end of the latch  500 . In FIG. 29B, the latch  500  is then pushed further through a cutout (direction shown) until the flange  532  of the housing  502  comes to rest against the panel  630 . The latch  500  is then slid in the cutout compressing the flat spring  511 . As illustrated in FIG. 29C, while being maintained in the compressed position the mounting clip  513  is pressed (direction shown) into the mounting clip aperture  555 , thereby trapping the latch  500  within the panel  630  upon release. Once fully installed, the latch  500  has the ability to move small distances based on the biasing on the flat spring  511 . Referring to FIG. 30, this ability is of particular importance because it allows adjustment after the panel  630  has engaged electronics within an enclosure but has not moved the pawl member  504  into the closed position. Compression of the flat spring  511  allows the pawl  504  to “clear” the lower frame member  410 B.  
         [0172]    A shown in FIGS. 31 through 34, activation of the latch  500  is similar to the preferred embodiment wherein the button member  506  is rotated so as to disengage the lip of the button  566  and the lip of the handle  586 . However, this movement is biased by the torsion spring  510  attached to the mounting bar of the button member  506 . Rotation of the button member  506  is limited by the ribs  544 A,  544 B within the housing  502  which act as a stop means for the button member body  564 . This allows the pawl member  506  to escape from within the upper  410 A and lower parts  410 B of an enclosure  510  thereby allowing removal of the module  520 . The handle  508  is driven by the camming portion  588 A of the torsion spring  510  held with the groove  575  of the handle  508 . Engagement closure occurs when the lip of the bottom member  566  is snapped over the lip of the handle  586 . This movement of the handle  502  to the closed position is biased by the torsion spring  510 .  
         [0173]    A third embodiment of a latch in accordance with the present invention is illustrated in FIGS. 35 through 41. The latch  700  of the third embodiment is similar in both structure and function to many of the features already described in detail with respect to the latch  100 . Therefore, only the alternate features embodied in the latch  700  will be described.  
         [0174]    Referring to FIGS. 35, 35A through  35 E, and  36 , the third embodiment latch  700  in the closed position. This latch  700  includes a housing  702 , a pawl member  704 , a button member  706 , a handle  708 , a torsion spring  710 , and pin members  714 ,  716 ,  718  and  719 . The pawl member has a longitudinal aperture  756  and an rear aperture  754  which are shaped so as to limit the rotation of the handle  708  after disengagement from the button member  706 .  
         [0175]    Shown in FIGS.  37  to  41 , latch  700  activation is accomplished as in the preferred embodiment  100  and the second embodiment  500  wherein the button member  706  disengages the handle member  708 . The latch  700  is driven by the torsion spring  710  to a first position as guided by the shape of the longitudinal pawl member  756 . The forward pin member  716  is stopped at the first curved portion  756 A. Further rotation by the operator will bring the forward pin member  716  to the second curved portion  756 B wherein it will stop until further rotation by the operator moves the forward pin member  716  to a third position  756 C at the extreme rear end of the aperture  756 . Further rotation of the handle  708  moves the middle pin member  719  in the central aperture  754  from a first position  754 A to a second position  754 B wherein the pawl  704  is forced against the bottom of the housing  730  at full rotation. At full rotation, the handle  708  is at an arc of approximately 115 degrees from the flush position.  
         [0176]    A fourth embodiment of a latch  900  in accordance with the present invention is shown in FIG. 42. This latch  900  is similar in both structure and function to many of the features already described in detail with respect to the latch  100 , and for this reason, only the differences between the latch  900  and the latch  100  will be discussed.  
         [0177]    Referring to FIG. 42, latch  900  is shown in cross-section, mounted in a panel and in the closed position. The latch  900  includes a housing  902 , a pawl member  904 , a handle  908 , a torsion spring  910 , and a pin member  914 . The handle  908  has a central portion  908 A which is flush with the housing between a first end  908 B and a second end  908 C. The first end  908 B has a hook portion  982  at one end substantially perpendicular to the central portion  908 A extending into the housing  902 . The central portion  908 A terminates at the second end  908 B wherein an aperture  980  is located having a pin member  914  there through for rotation of the handle  908 . A camming portion  994  substantially perpendicular extends into the housing  902  from the second end  908 C.  
         [0178]    The pawl member  904  has an elongated tail  905  section which has a perpendicular camming  907  surface aligned with the camming portion  994  of the handle  908 . The pawl member  904  slides along the bottom of the housing  930  wherein a space is formed between the pawl member  904  and central portion of the handle  908 A wherein a torsion spring  910  is located. The torsion spring  910  is impaled at its forward end  910 A on a spring post  997  extending substantially perpendicular to the pawl camming portion  907 . The rear end of the torsion spring  910 B is impaled on the housing spring post  999  extending from the recessed section of the housing  930 A.  
         [0179]    Activation of the latch  900  is accomplished by lifting the handle  908  (direction shown) out of the housing  902  by a hook portion of the handle  982  wherein the handle camming portion  994  drives the pawl camming portion  907  rearward thereby disengaging the pawl  904  from the frame  810 .  
         [0180]    The retainer clamp, FIGS.  9 - 9 E, which is implemented as a wire bail  112 , can also be provided as a second embodiment within the present invention, being bail  1148 , FIGS.  43 - 46 . This bail  1148 , like the first bail  112 , is essentially a rectangular-shaped wire loop. This loop has a partially open end  1149  formed by two juxtaposed inwardly extending ends  1150 A and  1150 B of the wire loop  1148 . These wire ends  1150 A,  1150 B, as with the first embodiment, are inserted into the housing portion of the latch, below its flange, to pivot on the wire ends. This housing mounting an pivoting is identical for both the first and second embodiments, bails  112  and  1148 .  
         [0181]    The retainer  1148  wire structure includes bends therein at various locations along its length. These bends add to the strength, and resiliency of the bail  1148  after bending. The retainer, bail  1148 , carries these bends with at least one projecting portion  1158  extending towards the panel or drawer face plate and extending a sufficient distance to come in abutted contact when the latch is clamped into place after being inserted though the prepared cutout in the panel or drawer face plate.  
         [0182]    The bail  1148  has four projecting portions  1158  , with two each spaced along each side (side leg) of the loop. The projecting portions  1158  provide the spring force to strongly hold the flange latch housing against the panel (drawer face plate) prevent any play (movement) of the latch when clamped in place, even as the thickness of the panel (drawer face plate) varies within predetermined limits.  
         [0183]    The projecting portions  1158  are formed by approximately V-shaped bends in the bail  1148  wire. Alternatively, the projecting portions  158  may be formed by approximately U-shaped bends.  
         [0184]    Positioned at approximately mid-length along each side of the bail  1158  is a respective inwardly projecting bend  1152 A and  1152 B. These mid-length bends  1152 A,  1152 B face each other and engage slots in the mating housing described below. These housing slot engagement bends  1152 A,  1152 B engage their respective cooperating housing slots act, as locks to hold the housing and clamp  1148  in the fully clamped position with respect to each other.  
         [0185]    The closed end of the wire loop carries a further inwardly facing bend  1156 , which extends towards the open end  1149  of the bail  1148 . This end bend  1156  engages a cooperating slot in an outwardly extending plate in the panel or drawer face plate when the latch housing is in the fully clamped position, i.e. when the engagement bends  1152 A,  1152 B engage the housing slots. This engagement locks the bail  1148 , and therefore the housing to the abutted back face of the panel or drawer face plate. The engagement of all three bends  1152 A,  1152 B,  1156 , with their respective slots, provides a three point interlocking. These bends  1152 A,  1152 B,  1156 , like the others in the wire loop bail  1148 , can be V-shaped or U-shaped.  
         [0186]    The second embodiment bail  1148  mating latch housing  1108 , FIGS.  47 - 50 , includes a respective receiving elongate slot  1150 A,  1150 B, one on each side thereof. These receiving slots run parallel to the abutment plane of the mounting panel (drawer face plate) which is also parallel to the housing  1108  flange  1124 . On each side wall of the housing  1108 . at the end where the pull latch pivots is a receiving pivot hole  1162 A,  1162 B for receiving a respective one of the wire ends  1150 A,  1150 B. This permits the bail  1108  to pivot. i.e., rotate relative to the position of the housing  1108  during insertion and removal through the panel (drawer face plate) cutout with notches (bump-outs).  
         [0187]    The second embodiment of the bail FIGS.  43 - 46  and of the mating housing  47 - 50  are shown as an assembly in FIGS.  51 - 54 . As seem the bail is closed and abuts the flange  1124 . When the latch is installed on a panel plate through a cutout, the flange  1124  rides on the outside face of the panel plate and the bail  1148  bends  1158  press against the inside face of the panel plate.  
         [0188]    Detailed insertion assembly and bail clamping of the two embodiments of the latch are shown in partial  
         [0189]    perspective close-up views in FIGS.  55 - 60 , with the first housing and bail embodiments shown in FIGS.  55 - 57  and the second bail embodiment and matching housing shown in FIGS.  58 - 60 .  
         [0190]    Referring to FIGS.  55 - 57 , with the bail  112  rotated at a right angle to the panel plate  30 , the bail  112  will pass through the notches  2011 ,  2013 , which are bump-outs in the opposing side edges at a first end of the cutout  34 . A pair of notches  2015 ,  2017  which are bump-outs in the opposing side edges at the second end of the cutout  34  provide space for passage of the ramp projections  142 A,  142 B which hold and lock the bail  112  in clamped position. The flange  132  seats against the outside face of the panel plate  30 , while the bail  112  engages the ramps  142 A,  142 B. The location of the ramps is such in relation to the thickness of the plate  30 , so that the abutment bends  192 A,  192 AA exert a spring force against the inside face of the plate  30 , when rotated to ride over the ramps and be held thereby.  
         [0191]    Referring to FIGS.  58 - 60 , with the bail  1148  rotated at a right angle to the panel plate  1030 , the bail  1148  will pass through the notch, bump-outs  2031 ,  2033  in the rectangular cutout  2034  in the plate  1030 . The bump-outs  2031  and  2033  are formed by the outward standing plate sections  2032  and  2034 , respectively. These plate sections  2032 ,  2034  act as guides for sliding the bail  1148  through the cutout opening  2034 . After the latch housing  1108  is fully inserted, FIG. 59, the bail  1148  is rotated, FIG. 60 so that the engagement bends  1152 A,  1152 B engage their mating housing receiving slots  1050 A,  1050 B, and the projecting bends  1158  each come into spring contact with the inside face of the panel plate  1030 .  
         [0192]    The housing and appropriate components of each latch embodiment are coated with a suitable commercial conductive layer to reduce or eliminate EMI and ESD events.  
         [0193]    Many changes can be made in the above-described invention without departing from the intent and scope thereo. It is therefore intended that the above description be read in the illustrative sense and not in the limiting sense. Substitutions and modifications can be made while remaining within the scope and intent this invention including that recited in the appended claims.

Technology Classification (CPC): 7