Abstract:
A method and apparatus for controlling removal of a circuit board module from a chassis comprising an actuator and an electrical switch. The actuator having a locked state and an unlocked state, where the circuit board module is removable from the chassis when the actuator is in the unlocked state and the circuit board module is not removable when the actuator is in the locked state. The electrical switch is coupled to the actuator to produce a first signal indicating the locked state and a second signal indicating the unlocked state.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a circuit board module and, more particularly, to a method and apparatus for controlling removal of a circuit board module from a chassis. 
     BACKGROUND 
     Circuit board modules (i.e., line cards) that connect to backplanes typically include ejectors that, when rotated by technicians, enable the technicians to operatively connect the line cards with the backplanes, and disconnect the line cards from the backplanes. In particular, when a technician inserts a line card into a card cage (chassis) and then rotates a handle of the ejectors toward the card cage, the ends of the ejectors grab the card cage and guide the line card into connection with a backplane at the back of the card cage. Furthermore, when the technician rotates the handles of the ejectors away from the card cage, the ends of the ejectors push against the card cage and disconnect the line card from the backplane. 
     Generally, the ejectors are equipped with thumb screws on a faceplate of the circuit board module to provide secure contact between connectors of the backplane and connectors of the circuit board module. If the module is removed without first deactivating the module, signal loss occurs that may adversely affect the signal traffic being processed by the line card. Such an interruption can cause inefficient handling of data throughout a system in which the circuit board module participates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages of the invention will be apparent from the following description of particular embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
         FIG. 1  is a perspective view of an example electronic system having at least one circuit board module. 
         FIG. 2  is a perspective view of the ejector shown in  FIG. 1 . 
         FIG. 3  is an exploded view of the ejector shown in  FIG. 2 . 
         FIG. 4  is a side view of the ejector shown in  FIG. 2  with the handle in a lock state and a closed position. 
         FIG. 5  is a side view of the ejector shown in  FIG. 2  with the handle in an unlock state and a closed position. 
         FIG. 6  is another side view of the ejector shown in  FIG. 2  with the handle in a unlock state and an open position. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Overview 
     Embodiments of the present invention include a method and apparatus for controlling removal of a circuit board module from a chassis comprising an actuator and an electrical switch. The actuator having a locked state and an unlocked state, where the circuit board module is removable from the chassis when the actuator is in the unlocked state and the circuit board module is not removable when the actuator is in the locked state. The electrical switch is coupled to the actuator to produce a first signal indicating the locked state and a second signal indicating the unlocked state. 
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view of an example electronic system that employs an ejector that facilitates safe removal of the circuit board module from a chassis in accordance with embodiments of the present invention. The electronic system  10  includes a chassis  12  and a motherboard  14  disposed within the chassis  12 . The electronic system  10  comprises a circuit board module  100 , which can be inserted in the chassis  12  to connect with the motherboard  14 . The circuit board module  100  comprises a circuit board  110  and a set of circuit devices  120  mounted thereon. The circuit board module  100  comprises a support member  130  fastened to the circuit board  110  and at least one ejector  140  coupled to the support member  130 . In the present embodiment, a pair of the ejectors  140  are applied for facilitating insertion and extraction of the circuit board module  100 . For illustration purpose, only one ejector  140  is shown and described as an example below. 
       FIG. 2  is a perspective view of the ejector  140  shown in  FIG. 1 .  FIG. 3  is an exploded view of the ejector  140  shown in  FIG. 2 .  FIGS. 2 and 3  show only a portion of the support member  130 . The ejector  140  comprises a support member  130 , a handle  142 , a shaft  143   a , an actuator  145  and a biasing spring  143   b . The handle  142  is pivotally attached to the support member  130  via the shaft  143   a  passing through the support member  130  and the handle  142 . The shaft  143   a  is press fit into the support member  130  to form an axle about which the handle rotates. The spring  143   b  is disposed between the support member  130  and the handle  142  in the open position. Although the shaft  143   a  is depicted as being a separate component in this embodiment, in other embodiments, the shaft  143   a  may be an integral element of the handle or an integral element of the support member  130 . 
     The ejector  140  further comprises the actuator  145  for locking and unlocking the handle  142 . The actuator  145  comprises a button  144 , a plunger  146  and an electrical switch  148 . The button  144  is slidably installed in the support member  130 . The plunger  146  is slidably installed in the support member  130 . The button  144  is coupled to the handle  142  via the plunger  146 . The electrical switch  148  is installed in the support member  130  proximate to the plunger  146  such that the movement of the plunger  146  can activate or deactivate the electrical switch  148  i.e., change the state of the switch. 
       FIG. 4  is a side view of the ejector  140  shown in  FIG. 2  with the handle  142  in a locked state and closed position.  FIG. 5  is a side view of the ejector  140  shown in  FIG. 2  with the handle in an unlocked state and closed position.  FIG. 6  is a side view of the ejector  140  shown in  FIG. 2  with the handle in an unlocked state and opened position. As illustrated in  FIGS. 2 ,  4 ,  5  and  6 , the button  144  is coupled to the handle  142  via the plunger  146 . By depressing the button  144 , the handle  142  can be rotated from a locked state as shown in  FIGS. 4 and 5  to an unlocked state as shown in  FIG. 6 . As the handle is rotated, the plunger  146  moves to change the state of the switch  148 . 
     The handle  142  of the ejector  140  is pivotally attached to the support member  130  such that the handle rotates about an axis A. The handle  142  swings between an opened position as shown in  FIG. 5  and a closed position as shown in  FIG. 6 . The handle  142  is configured to grip chassis  12  in a traditional manner to apply insertion force as the handle is closed to reliably mate the circuit board module  100  with the motherboard  14 . In the depicted embodiment, the handle  142  comprises a chassis interface detent  142   b  that interfaces with the chassis  12  to form a fulcrum to move the module  100  into the chassis  12 . 
     In one embodiment, the plunger  146 , which is slidably installed in the support member  130 , is configured to move up and down from an unlocked position to a locked position. The plunger  146  comprises a block  146   a , a latch  146   b  and a flange  146   c . The block  146   a  forms the upper end portion of the plunger  146 , the latch  146   b  forms the lower end portion of the plunger  146 , and the flange  146   c  is located at a middle portion of the plunger  146 . The ejector  140  further comprises a biasing spring  149  which is disposed between the support member  130  and the plunger  146  for biasing the plunger  146  to move downward. In the downward position, the latch  146   b  is inserted into a latch hole  142   a  of the handle  142  when the handle  142  is in the closed position. The insertion of the latch  146   b  locks the handle  142  in the closed position. It should be understood that, because of the interaction of the detent  142   b  with the chassis  12 , the circuit board module  100  can only be removed when the handle  142  is in the opened position. It should be further understood that in order to swing the handle  142  to the opened position, the latch  146   b  of the plunger  146  must be released from the latch hole  142   a  of the handle  142 ; otherwise, the handle  142  cannot be swung to the opened position. 
     In one embodiment, the button  144  operates to either lock the circuit board module  100  or unlock the circuit board module  100 . In the depicted embodiment, the button  144  comprises a ramp  144   a . The ramp  144   a  is positioned corresponding to the block  146   a  such that when the button  144  is depressed into the support member  130 , the ramp  144   a  of the button  144  moves forward. Such movement slidingly moves the block  146   a  of the plunger  146  upward so that the latch  146   b  of the plunger  146  is released from the latch hole  142   a . Consequently, the handle  142  is unlocked. In this unlocked state, the handle  142  can be manually swung to the opened position to facilitate removal of the circuit board module  100  from the chassis  12 . 
     In one embodiment, the electrical switch  148  is installed in the support member  130  proximate to the plunger  146  such that the movement of the plunger  146  can activate or deactivate the electrical switch  148 . In the depicted embodiment, the electrical switch  148  comprises a trigger  148   a  for driving the electrical switch  148  to output a control signal to a processor or other circuitry to deactivate the circuit board module  100 . According to this embodiment, when the button  144  is manually depressed into the support member  130 , the ramp  144   a  of the button  144  moves forward. Such movement slidingly moves the block  146   a  of the plunger  146  upward so that the flange  146   c  of the plunger  146  releases the trigger  148   a  of the electrical switch  148 . The switch  148  is thereby activated to output the control signal to deactivate the circuit board module  100 . Meanwhile, the latch  146   b  of the plunger  146  is released from the latch hole  142   a  of the handle  142  to unlock the handle  142 . In this unlocked state, the handle  142  can be manually swung to the opened position to facilitate the removal of the circuit board module  100  from the chassis  12 . Thus, embodiments of the invention deactivate the circuit board module  100  before being removed out of the chassis  12 . Consequently, signal traffic reliability of the electronic system  10  may be improved and the down time of the electronic system  10  due to traffic interruption/loss may be reduced. 
     Hereinafter, the operation of the ejector  140  is described with reference to  FIGS. 4 ,  5  and  6  as follows. The circuit board module  100  is inserted into the chassis  12 , and the handle  142  is manually swung to the closed position as shown in  FIG. 5 . The latch hole  142   a  will align with the latch  146   b  of the plunger  146  so that the latch  146   b  is forced into the latch hole  142   a  in a direction V 2 . As shown in  FIG. 4 , movement of the latch  146   b  is due to the biasing force of the biasing spring  149  on the plunger  146 . Meanwhile, the ramp  144   a  of the button  144  is pushed in a direction H 2  due to the downward movement of the block  146   a  of the plunger  146 . In the locked state of the handle  142 , the flange  146   c  compresses the trigger  148   a  to deactivate the electrical switch  148 . To remove the circuit board module  100  from the chassis  12 , the button  144  is manually depressed in a direction H 1 . In doing so, the ramp  144   a  of the button  144  moves forward to slidingly move the block  146   a  of the plunger  146  upward in a direction V 1  as shown in  FIG. 5 . In response, the flange  146   c  of the plunger  146  releases the trigger  148   a  of the electrical switch  148  and thereby activates the electrical switch  148  to output the control signal. The control signal causes deactivation of the circuit board module  100 . Meanwhile, the latch  146   b  of the plunger  146  is released from the latch hole  142   a  of the handle  142  to unlock the handle  142  as shown in  FIG. 5 . In this unlocked state, the handle  142  can be manually swung to the opened position as shown in  FIG. 6  to facilitate removal of the circuit board module  100  from the chassis  12 . 
     Therefore, the ejector  140  of the depicted embodiment ensures the deactivation of the circuit board module  100  prior to removal thereof so that the signal traffic reliability of the electronic system  10  may be improved and the down time of the electronic system  10  due to traffic interruption/loss may be reduced. 
     The foregoing ejector embodiment is known as an external ejector wherein the detent  142   b  that interacts with the chassis  12  is located “outside” or “in front of” a front panel of the circuit board module. The use of a circuit module activation/deactivation switch is also applicable to internal ejectors wherein the latch that interacts with the chassis is “inside” or “behind” a front panel of the circuit board module. 
     Additionally, the disclosure above describes deactivating the circuit board module before removing the card from the chassis. Similarly, the method and apparatus of embodiments of the present invention are equally applicable to maintaining the circuit board module in a deactivation state until the module is inserted and locked into the chassis. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.