Abstract:
A latch assembly includes a closing panel having an end with a closing panel tab extending therefrom. A clasp lever is pivotally attached to the end of closing panel and forms a space into which the closing panel tab extends. Inner peripheral sidewalls of the clasp lever forming the space allow the clasp lever to rotate around outer peripheral sidewalls of the closing panel tab when the clasp lever pivots around the end of the closing panel. An incessant force component is disposed within the space between the closing panel tab and a rear inner sidewall of the clasp lever and biases the clasp lever to a neutral position with respect to the closing panel. A force applied to an outer surface of the clasp lever against the bias causes the clasp lever to pivot around the end of the closing panel from the neutral position.

Description:
FIELD OF INVENTION 
     The present invention relates in general to transportation containers, and in particular to latch assemblies suitable for use with transportation containers. 
     BACKGROUND OF INVENTION 
     Latch assemblies, including those used with transportation containers, are ubiquitous. Nevertheless, new latch assembly designs are always necessary to meet the challenges presented when new types of transportation containers are developed, new operating environments are faced, or both. Among other things, a properly designed and constructed latch assembly must provide for a firm engagement between container components (e.g., the container lid and the base), withstand the stresses of the intended operating environment, and allow for the use of efficient manufacturing processes. 
     SUMMARY OF INVENTION 
     One embodiment of the principles of the present invention is a latch assembly that includes a closing panel having an end with a closing panel tab extending therefrom. A clasp lever is pivotally attached to the end of closing panel and forms a space into which the closing panel tab extends. Inner peripheral sidewalls of the clasp lever around the periphery of the space allow the clasp lever to rotate past outer peripheral sidewalls of the closing panel tab when the clasp lever pivots around the end of the closing panel. An incessant force component is disposed within the space between a rear sidewall of the closing panel tab and a rear inner sidewall of the clasp lever and biases the clasp lever to a neutral position with respect to the closing panel. A force applied to an outer surface of the clasp lever against the bias causes the clasp lever to pivot around the end of the closing panel from the neutral position. 
     Latch assemblies according to the inventive principles advantageously require significantly less force to engage and disengage from the associated container, in comparison to traditional one-piece latches, while still providing the required security under a wide range of conditions. Furthermore, the ergonomic design of these latch assemblies allows the user to engage and disengage the latch using natural gestures, which minimizes fatigue and maximizes user comfort. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1A  is a diagram of a portion of a transportation container with a representative latch assembly embodying the principles of the present invention, with the latch assembly shown in the engaged (latched) configuration; 
         FIG. 1B  is another diagram illustrating the representative latch assembly in the disengaged (unlatched) configuration; 
         FIGS. 2A and 2B  are diagrams providing front and rear exploded views of the latch assembly of  FIGS. 1A and 1B ; 
         FIG. 3A  is a diagram providing a cross-sectional view taken along line  3 A- 3 A of  FIG. 1B  showing the latch assembly in the disengaged configuration; 
         FIG. 3B  is a diagram providing a cross-sectional view taken along line  3 B- 3 B of  FIG. 1A  showing the latch assembly just before or just after the engaged configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The principles of the present invention and their advantages are best understood by referring to the illustrated embodiment depicted in  FIGS. 1-3  of the drawings, in which like numbers designate like parts. 
       FIGS. 1A and 1B  illustrate an exemplary transportation container  101  utilizing a spring latch assembly  100  according to a preferred embodiment of the present inventive principles.  FIG. 1A  shows latch assembly  100  in the engaged (latched) configuration and  FIG. 1B  shows latch assembly  100  in the disengaged (unlatched) configuration. 
     As shown in  FIGS. 1A and 1B , transportation container  101  is a molded plastic container suitable for use as luggage or for transporting tools, musical instruments, or other equipment. Transportation container  101  generally includes an upper or lid section  102  that pivots with respect to a lower or base section  103  at axis points (not shown) at the opposing side the container. Alternatively, lid section  102  and base section  103  are completely separable. The construction of transportation container  101  may change as a matter of design choice. For example, transportation container  101  may be constructed of different materials (e.g., metal), or the size, shape, or external appendages may change, depending on the desired aesthetics or intended use. 
     One end of a closing panel  107  of latch assembly  100  is attached to upper container section  102  with a upper fixed pin  104  Upper fixed pin provides a fulcrum (axis) point around which latch assembly  100  pivots. Lower fixed pin  105  provides a fulcrum (axis) point around which a clasp lever  106  pivots with respect to closing panel  107 . 
       FIG. 2A  is an exploded view taken from the front of latch assembly  100 , including closing panel  107  and clasp lever  106 . Closing panel  107 , which in the illustrated embodiment is single body of molded plastic, includes a thumb grip surface on a tab  200 , downward (inward) rotational travel-limiting surfaces  201 , and a pivot lock rib  202 . An aperture  203  receives upper fixed pin  105 . Aligned apertures  204  receive lower fixed pin  105 . 
     Clasp lever  106 , which is also preferably a single, generally V-shaped, body of molded plastic, includes encasement pocket  205  extending into the body of a rear portion of clasp lever  106 , an alignment rod  206  encompassed by encasement pocket  205  and extending outward from the rear wall of the clasp lever body, a clasp upward (outward) rotational travel-limiting surface  207 , clasp downward (inward) rotational travel-limiting surface  208 , and four (4) lateral shifting and travel limiting surfaces  209 . Aligned apertures  210  receive lower fixed pin  105 . 
     An incessant force component  211 , which is preferably a helical spring, is disposed between closing panel  107  and clasp lever  106 , with the spring longitudinal aperture receiving clasp lever alignment rod  206 . 
       FIG. 2B  is an exploded view taken from the back of latch assembly  100 . As shown in  FIG. 2B , closing panel  107  also includes an encasement pocket  212  extending into the body of closing panel  107 , an alignment rod  213  encompassed by encasement pocket  212  and extending outwardly, upward (outward) travel-limiting surface  214 , and four (4) lateral shifting travel-limiting surfaces  215 . Clasp lever  106  further includes latch hook  216  and a ribbed thumb grip surface  217 . 
     As shown in  FIG. 2A , the front portion of the V-shaped by body of clasp lever  106  defines a space that receives tab  200  of closing panel  107  between sidewalls  220  of clasp lever  106  ( FIG. 2B ). Clasp lever extensions  221  are received into closing panel receptacles  222  defined by corresponding pairs of lateral shifting travel-limiting surfaces  215  ( FIG. 2B ). Apertures  204  of closing panel  107  align with apertures  210  on clasp lever  106 . Lateral shifting and travel limiting surfaces  209  on clasp lever  106  are disposed adjacent corresponding lateral shifting travel-limiting surfaces  215  on closing panel  107 . 
     Lower fixed pin  105  extends through aligned apertures  204  and  210 . The narrower section  218  of lower fixed pin  105  allows clasp lever  106  to pivot with respect to closing panel  107  to the extent allowed by rotational travel-limiting surfaces  201  (closing panel  107 ),  207  (clasp lever  106 ),  208  (clasp lever  106 ), and  214  (closing panel  107 ). The larger diameter end section  219  of lower fixed pin  105  is held tightly within the corresponding aperture of closing panel  107 , thereby holding clasp lever  106  and closing panel  107  together. 
     When latch assembly  100  is fully assembled, one open end of incessant force component  211  extends (slides) over alignment rod  206  within encasement pocket  205  of clasp lever  106 . The other open end of incessant force component  211  extends (slides) over alignment rod  213  within encasement pocket  212  of closing panel  107 . Generally, the longitudinal axis through the open center of incessant force component  211  aligns with the longitudinal axis of alignment rods  206  and  214  in the completed assembly. Thus, while incessant force component  211  is encased within the assemblage of closing panel  107  and clasp lever  106 , and held in place by alignment rods  206  and  213 , it is not otherwise attached to either closing panel  107  or clasp lever  106 . 
     In the neutral position, when no force is applied between tab  200  on closing panel  107  and thumb grip surface  217  on clasp lever  106 , incessant force component  211  maintains downward (inward) rotational travel-limiting surfaces  201  of closing panel  107  in contact with downward (inward) rotational travel-limiting surface  208  of clasp lever  106 . The ribbed upper surface of tab  200  of closing panel  200  is generally parallel or slightly above the surrounding surface of the clasp lever  106 . 
     When pressure is applied to thumb grip surface  217  of clasp latch  106 , and the thumb grip of tab  200  of closing panel  107 , as necessary, incessant force component  211  compresses. The force allows clasp lever  106  to pivot around lower fixed pin  105  such that sidewalls  220  travel, at least in part, past the sidewalls and upper surface of tab  200  on closing panel  107 . Hook  216  rotates outward with the remainder of clasp lever  106 . Outward motion of clasp lever  106  stops when travel-limiting surface  214  on closing panel  107  contacts travel-limiting surface  207  of clasp lever  106 . 
       FIG. 3A  is a cross-sectional view taken along line  3 B- 3 B of  FIG. 1A  showing of a portion of transportation container  101  with latch assembly  100  in the disengaged configuration. In the disengaged configuration, latch assembly  100  has pivoted upward around upper fixed pin  104  until travel was halted by pivot lock rib  202 . Incessant force component  211  has biased closing panel  107  and clasp lever  106  to their neutral position. Container lid  102  now freely moves with respect to container base  103  and pressure on gasket  300  is released. 
       FIG. 3B  is a cross-sectional view transportation container  101  taken along line  3 A- 3 A of  FIG. 1B  showing latch assembly  100  just prior to engagement or just after disengagement. As shown in  FIG. 3B , latch hook  216  is in contact with the outer surface of container latch hook  301  and outside of container latch hook depression  302 . Container element barrier  303  is in contact with gasket  300 , although gasket  300  is not being fully compressed. 
     To engage latch assembly  100  with container  101 , inward pressure is applied to thumb grip surface on tab  200  on closing panel  107 . Outward pressure is applied to thumb grip surface  217  on clasp lever  106 , against the bias presented by incessant force component  211 . Latch hook  216  rotates outward and downward around lower fixed pin  105 , such that hook  216  is able to clear container latch hook  301  as inward force on thumb grip surface  200  causes latch assembly  100  as a whole to pivot further downward and inward around upper fixed pin  104 . When the pressure on thumb grip surface  217  is released, incessant force component  211  causes hook  216  to pivot inward and upward into the neutral position and engage container latch hook  301  and container latch depression  302 . 
     To disengage latch assembly  100  from container  101 , outward pressure is applied to thumb grip surface  217  on clasp lever  106 . Latch hook  216  rotates outward and downward against the bias presented by incessant force component  211 , which allows latch hook  216  to clear container latch hook  301  as continued outward pressure applied to thumb grip surface  217  causes latch assembly  100  as a whole to rotate upward and outward around upper fixed pin  104 . 
     Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed might be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
     It is therefore contemplated that the claims will cover any such modifications or embodiments that fall within the true scope of the invention.