Abstract:
An apparatus for locking a printed circuit board inside a card cage is disclosed. For one embodiment of the locking assembly, the locking assembly is mounted on a printed circuit board. The locking assembly is movable from a unlocked position to a locked position to lock the printed circuit board into the card cage. The locking assembly is unmovable to return to the unlocked position without the aid of a separate unlocking mechanism.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a locking tool. More specifically, the present invention relates to an improved apparatus for locking a printed circuit board into a card cage. 
     BACKGROUND OF THE INVENTION 
     Modern computer systems often are assembled by interconnecting various electronic modules on printed circuit boards. The printed circuit boards are commonly loaded into racks or “card cages,” which facilitate the mounting and connection of the electronic modules. Card cages are a form of housing for supporting printed circuit boards in compact or dense configurations. Card cages typically comprise an open framework with a top, bottom, back, and sides. Front support rails define an open front through which the printed circuit boards are inserted into the card cage. The back typically supports a backplane with backplane connectors for receiving mating connectors on a rear edge of each printed circuit board. Rails attached to the top and bottom or to the sides or intermediate locations engage parallel edges of the printed circuit board to guide the printed circuit board into the card cage in either a vertical or horizontal orientation, to align the printed board connector with a corresponding backplane connector, and to support the printed circuit board after it is seated in the card cage. 
     It is often desirable to lock the printed circuit board in place. For example, commercial underwriters impose requirements on manufacturers of systems that have printed circuit boards operating at voltages above a certain level. The manufactures must provide safety mechanisms that prevent individuals from accidentally accessing the printed circuit boards. 
     In the past, manufacturers used machine screws that lead through lead holes in the front panel. These screws thread into a front support rail to provide the locking function required by the commercial underwriters. This approach, however, required that an individual take additional time to thread and unthread the screws through the front support rail whenever a printed circuit board was put in or taken out of the card cage. It was also possible for individuals to bypass the locking function by simply not threading the screws at all. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     One object of the present invention is to provide a locking mechanism that is easy to use. 
     Another object of the present invention is to provide a locking mechanism that may not be bypassed. 
     Another object of the present invention is to provide a locking mechanism that inserts the printed circuit board into a connector in the card cage when the locking mechanism is moved from an unlocked position to a locked position. 
     A further object of the present invention is to provide a locking mechanism that extracts the printed circuit board from a connector in the card cage when the locking mechanism is moved from a locked to a unlocked position. 
     An apparatus is described that includes a printed circuit board, a card cage, and a locking and latching assembly mounted on the printed circuit board. The locking and and latching assembly is movable from an unlocked position to a locked position to lock the printed circuit board into the card cage. The locking and latching assembly is unmovable to return to the unlocked position without an aid of a separate unlocking mechanism. 
     Other objects, and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements and in which: 
     FIG. 1 illustrates an embodiment of the latching and locking assembly as used for locking a printed circuit board in a card cage. 
     FIG. 2 a  illustrates an embodiment of the latching and locking assembly with the extractor in a position approximately 90 degrees with respect to the face plate. 
     FIG. 2 b  illustrates an embodiment of the latching and locking assembly with the extractor in a position approximately 45 degrees with respect to the face plate. 
     FIG. 2 c  illustrates an embodiment of the latching and locking assembly with the latch partially engaged with an opening in the face plate. 
     FIG. 2 d  illustrates an embodiment of the latching and locking assembly in the locked position with the latch engaged with an opening in the face plate. 
     FIG. 3 is an exploded view of an embodiment of the latching and locking assembly of the present invention. 
     FIG. 4 illustrates a backside view of an embodiment of the latching and locking assembly. 
     FIG. 5 a  illustrates a printed circuit board with a locking and latching assembly in an unlocked position. 
     FIG. 5 b  illustrates a printed circuit board with a locking and latching assembly in a locked position. 
     FIG. 6 illustrates how the latch is disengaged from an opening in the face plate through the use of an unlocking mechanism. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates an embodiment of the latching and locking assembly  150  used for locking a printed circuit board  130  in a card cage  110 . Card cage  110  houses a plurality of printed circuit boards. Card cage  110  is a rectangular prism shaped frame having a closed back and an open front. Card cage  110  comprises a top panel  111 , a bottom panel  112 , two side panels  113  and a back panel  114 . Card cage  110  is adapted to mount a plurality of printed circuit boards  130  and  131 . The top panel  111  of card cage  110  comprises a channel  116  that runs along the edge of the top panel facing the front of the card cage  110 . Channel  116  comprises an inner wall that faces the front of card cage  110  and an outer wall that faces the back of card cage  110 . 
     A plurality of rails  120  are provided to slidably receive the printed circuit board  130 . The rails  120  are provided on at least one of the panels that define each printed circuit board mounting area. The back panel  114  of card cage  110  has electrical connectors  125  adapted to engage the electrical connectors  135  of the printed circuit boards  130 . Interconnection of the printed circuit board  130  into a system is facilitated thereby. 
     Locking and latching assembly  150  is attached to printed circuit board  130 . Locking and latching mechanism  150  is shown to be in an unlocked position. Printed circuit board  130  is allowed to slide freely in and out of card cage  110  along rails  120 . When locking and latching mechanism  150  is moved from an unlocked position to a locked position, an extractor element in the locking and latching mechanism  150  catches the channel  116  on the top panel  111  of the card cage  110  to lock the printed circuit board in the card cage  110 . 
     FIG. 2 a  illustrates a cross-section view of card cage  110  and side view of locking and latching mechanism  150 . Locking and latching mechanism  150  comprises face plate  230 . Face plate  230  is attached printed circuit board  130 . A lever  210  is rotatably mounted on face plate  230  by pin  240 . An extractor element  220  is also rotatably mounted on face plate  230  by pin  240 . Extractor element  220  is attached to lever  210  by pin  241  such that extractor element  220  rotates with lever  210 . Extractor element  220  has a tab portion  221  that resides inside a channel  225  in face plate  230  when extractor element  220  is in a position that is approximately 90 degrees with respect to face plate  230 . Latch  215  is rotatably mounted on lever  210  by pin  241 . Latch  215  comprises a back portion  216  and a hook portion  217 . A spring element  245  is mounted on face plate  230  by pin  240 . Spring element  245  is in contact with face plate  230  and lever  210  and operates to exert pressure on latch  215  such that latch  215  rotates counter-clockwise around pin  241  and back portion  216  of latch  215  pushes firmly against lever  210 . 
     FIG. 2 b  illustrates an embodiment of the latching and locking assembly  150  with the extractor element  220  in a position that is approximately 45 degrees with respect to the face plate  230 . As illustrated in FIG. 2 b,  extractor element  220  is attached to lever  210  such that the extractor element  220  rotates counter-clockwise around pin  240  with lever  210  when lever  210  is pushed downward to rotate counter-clockwise around pin  240 . As extractor element  220  and lever  210  rotates counter-clockwise, tab portion  221  moves out of channel  225  and into channel  116 . Tab portion  221  hooks against the outer wall  251  of channel  116  such that the counter-clockwise rotation of lever  210  and extractor element  220  around pin  240  pushes printed circuit board  130  further in the card cage  110  and pushes connectors  135  on the printed circuit board into connectors  125  in the card cage  110 . 
     FIG. 2 c  illustrates an embodiment of the latching and locking assembly  150  with the extractor element  220  in a position which is approximately 20 degrees with the face plate  230 . In this position, as lever  210  continues to rotate counter-clockwise around pin  240 , the hook portion  217  of latch  215  pushes against the edge of opening  231  in face plate  230 . As the force used to rotate lever  210  counter-clockwise around pin  240  exceeds the pressure of spring  245 , latch  215  rotates clockwise around pin  241 . The back portion  216  of latch  215  is pushed away from lever  210  as the hook portion  217  of latch  215  becomes partially engaged with opening  231  in the face plate. The back portion  216  of latch  215  is positioned between lever  210  and extractor element  220 . Extractor element  220  supports the back portion  216  of latch  215  and prevents latch  215  from rotating counter-clockwise more than approximately 30 degrees regardless of how much pressure is exerted on lever  210  to rotate lever  210  counter-clockwise around pin  240 . As tab portion  221  of extractor element  220  continues to rotate counter-clockwise around pin  240  with lever  210 , connectors  135  of printed circuit board  130  are pushed farther into connectors  125  in card cage  110 . 
     FIG. 2 d  illustrates an embodiment of the latching and locking assembly  150  with the extractor element  220  in a position that is approximately 0 degrees with respect to face plate  230 . As illustrated in FIG. 2 d,  lever  210  is rotated such that the hook portion  217  of latch  215  is inside opening  231  of face plate  230 . When hook portion  217  is inside opening  231 , hook portion  217  no longer pushes against the edge of opening  231 . This allows spring element  245  to push the back portion  216  of latch  215  firmly against lever  210 . This causes latch  215  to rotate counter-clockwise around pin  241  and engage opening  231  such that hooked portion  217  is locked inside opening  231 . Lever  210  and extractor element  220  are locked in this position, which causes tab portion  221  to be unmovable. As a result, tab portion  221  locks printed circuit board  130  inside card cage  110 . 
     The most effective way for connecting connectors  135  of printed circuit board  130  with electrical connector  125  is to use tab portion  221  to exert a force for inserting printed circuit board  130  inside card cage  110 . Tab portion  221  pushes against outer wall  221 , which causes circuit board  130  to be pushed completely into card cage  110 . Locking and latching assembly  150  automatically locks printed circuit board  130  into card cage  110  as tab portion  221  is rotated to a position where connectors  135  of printed circuit board  130  are in contact with electrical connector  125 . Thus, the locking feature of locking and latching assembly  150  may not be bypassed when using tab portion  221  to insert connectors  135  into connectors  125 . 
     FIG. 3 illustrates an exploded view of locking and latching assembly  150 . Lever  210  has a front side  301  and a back side  302 . The front side  301  of lever  210  has a flat surface. The front side  301  of lever  210  faces the front side of card cage  110  when lever  210  is in a locked position. The back side  302  of lever  210  has pin supporter  305  for holding pin  240 . Pin  240  operates to rotatably mount lever  210 , extractor element  220 , and spring element  245  onto face plate  230 . The back side  302  of lever  210  has pin supporter  306  for holding pin  241 . Pin  241  operates to rotatably mount latch  215  onto lever  210  and to attach extractor element  220  to lever  210 . 
     Extractor element  220  has a back portion  310  and a tab portion  221 . Extractor element  220  has a first hole  311  and a second hole  312 . The first hole  311  in extractor element  220  is used for threading pin  240  into extractor element  220 . Pin  240  operates to rotatably couple extractor element  220  onto face plate  230 . The second hole  312  in extractor element  220  is used for threading pin  241  into extractor element  220 . Pin  241  is used for attaching extractor element  220  to lever  210 . When extractor element  220  is attached to lever  210 , the back portion  310  of extractor element  220  presses firmly against lever  210  such that pressure applied to the front side  301  of lever  210  causes extractor element  220  to rotate with lever  210  around pin  240 . Extractor element  220  is made of a material that is strong enough to withstand pressure and successfully lock printed circuit board  130  in cage  110  by catching channel  116  on top panel  111 . For one embodiment of the present invention, extractor element  220  is made of metal. 
     Spring element  245  comprises a first end  316 , a second end  315 , a base portion  317 , and coils  318 . Pin  240  is threaded through coils  318  to mount spring element  245  on face plate  230 . Base portion  317  of spring element  245  is in contact with face plate  230  and pushes against face plate  230 . First end  316  of spring element  245  is in contact with lever  210  and pushes against lever  210 . Second end  315  of spring element  245  is in contact with latch  215  and applies a force on latch  215  such that latch  215  rotates counter-clockwise around pin  241 , which causes the back portion  216  of latch  215  to be pushed firmly against the back side  302  of lever  210 . In one embodiment of the present invention, spring element  245  is a tension spring. In another embodiment of the present invention, spring element  245  is made from music wire. 
     Latch  215  comprises a back portion  216  and a hook portion  217 . Latch  215  has threaded holes  320 . Pin  241  threads through holes  320  to rotatably mount latch  215  on to lever  210 . 
     Face plate  230  comprises channel  225 , pin supporters  325 , and opening  231 . Pin supporter  325  operates to hold pin  240 . Pin  240  mounts lever  210 , extractor element  220 , and spring element  245  onto face plate  230 . Channel  225  is a recess that houses tab portion  221  of extractor element  220  when extractor element is approximately 90 degrees with respect to face plate  230 . When tab portion  221  is housed within channel  225 , printed circuit board  130  is free to slide in and out of card cage  110 . The hooked portion  217  of latch  215  enters into opening  231  when lever  210  is in the locked position. Hooked portion  217  engages opening  231  to lock lever  210  in the locked position. 
     Light panel  340  is mounted on face plate  230 . Light panel  340  has windows  345  for displaying light emitting diodes (LEDs) from printed circuit board  130 . Light pipes may be used for transmitting lights from the printed circuit board to windows  345  of light panel  340 . 
     Ground plate  350  is attached to face plate  230 . Ground plate  350  operates to block radiation from the printed circuit board  130  from radiating outwards towards face plate  230 . Ground plate  350  also operates to provide structural strength for face plate  230  to prevent it from bowing. Ground plate  350  comprises a plurality of holes  351  for screws for attaching printed circuit board  130 . 
     FIG. 4 illustrates the backside of a locking and latching assembly of one embodiment of the present invention. As illustrated in FIG. 4, the backside  302  of lever  210  has pin supporter  306  for holding pin  241  and pin supporter  305  for holding pin  240 . Pin  241  threads through latch  215  and extractor  220 . Pin  240  threads through extractor  220 , face plate pin supporter  325 , and the coils  318  of spring element  245 . The backside  302  of lever  210  also comprises inlet  411 . Inlet  411  operates to support the first end  316  of spring element  245 . 
     Latch  215  comprises hook portion  217  and channel  410 . Channel  410  operates to support the second end  315  of spring element  245 . The second end  315  of spring element  245  applies a force on latch  215  on channel  410 . 
     FIG. 5 a  shows a printed circuit board  130  with a locking and latching assembly  150  in an unlocked position. FIG. 5 b  shows a printed circuit board  130  with a locking and latching assembly  150  in a locked position. To lock the locking and latching assembly  150 , lever  210  must be depressed so that the lever  210  rotates counter-clockwise around pin  240 . Tab portion  221  of extractor element  220  rotates out of canal  225  and into channel  116 . As extractor element  220  rotates counter-clockwise with lever  210 , tab portion  221  pushes against the outer wall  251  of channel  116  and pushes printed circuit board  130  farther into card cage  110 . This results in the insertion of connectors  135  of printed circuit board  130  into connector  125  of the card cage  110 . 
     As illustrated in FIG. 5 b,  when locking and latching assembly  150  is in a locked position, spring element  245  operates to rotate latch  215  counter-clockwise along pin  241  until back portion  216  presses firmly against lever  210  and latch  215  is engaged with opening  231 . When latch  215  is engaged with opening  231 , lever  210  and extractor element  220  may not rotate in any direction. This causes tab portion  221  to be fixed in channel  116 , locking printed circuit board  130  in card cage  110 . 
     FIG. 6 illustrates how the latch  215  is disengaged from an opening  231  in the face plate  230  through the use of an unlocking mechanism  610 . Lever  210  comprises an opening  620  which extends from the front side  301  of lever  210  to the back side  302  of lever  210 . The opening  620  in lever  210  is adjacent to the back portion  216  of latch  215 . Unlocking mechanism  610  comprises a pointed edge  615  that may be used to slide through opening  620  on lever  210 . The pointed edge  615  of unlocking mechanism  610  may be used to exert force on the back portion  216  of latch  215  that exceeds the force of spring element  245 . When this force is exerted on the back portion  216  of latch  215 , latch  215  will rotate clockwise around pin  241  and disengage hook portion  217  of latch  215  from opening  231  in face plate  230 . When hook portion  217  is disengaged from opening  231 , lever  210  and extractor element  220  are free to rotate clockwise around pin  240  to an unlocked position. 
     To extract printed circuit board  130  out of card cage  110 , one may pull lever  210  upwards. By rotating lever  210  clockwise around pin  240 , tab portion  221  of extractor element  220  also rotates clockwise around pin  240 . Tab portion  221  pushes against the inner wall  252  of channel  116  and causes connectors  135  of printed circuit board  130  to be extracted from connector  125  of card cage  110 . 
     If unlocking mechanism  610  was used to unlock locking and latching assembly  150 , but printed circuit board  130  was still in card cage  110  such that connectors  135  of printed circuit board  130  were still connected with electrical connector  125 , one would be able to determine the locking status of latching and locking assembly by observing the position of lever  210 . When the latching and locking assembly  150  is unlocked, spring element  245  exerts pressure on lever  210  and rotates lever  210  clockwise around pin  240  such that lever  210  is at approximately 6 degrees with respect to face plate  230 . This is illustrated in FIG. 2 c  and with locking and latching assembly  151  in FIG.  1 . When latching and locking assembly  150  is in a locked position, lever  210  is at approximately 0 degrees with face plate  230 . This is illustrated in FIG. 2 d  and with locking and latching assembly  150  in FIG.  1 . Thus, the position of lever  210  gives an indication of the locking status of latching and locking assembly  150 . 
     In the foregoing description, the invention is described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specifications and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.