Abstract:
An ejector assembly for securing a modular assembly in a chassis is disclosed. The ejector assembly comprises a cam rotatably mounted to the modular assembly such that the cam may be rotated about a first axis, the cam having a control member configured to extend into a recess in the chassis when the cam is rotated into a locked position and be retracted from the recess when the cam is rotated into a retracted position; and a lever rotatably mounted to the modular assembly such that the lever may be rotated about a second axis substantially parallel to the first axis, the lever being configured to cause the cam to be rotated about the first axis when a force is applied to the lever to rotate the lever about the second axis, whereby the cam may be rotated into either the locked position or the retracted position by operating the lever.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 60/475,218 (Attorney Docket No. TIMEP023+) entitled Cam and Lever Ejector Assembly filed May 30, 2003, which is incorporated herein by reference for all purposes. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to modular assemblies. More specifically, a cam and lever ejector assembly is disclosed.  
         BACKGROUND OF THE INVENTION  
         [0003]    Modular systems are used in many applications to provide flexibility and facilitate repair, maintenance, and upgrades. In the telecommunications industry, it is common to provide a system chassis or back plane into which one or more modular components, such as printed circuit boards, may be inserted.  
           [0004]    To facilitate the insertion and removal of such modular components, and to enable such components to be locked into place once installed, a variety of locking and ejection devices have been provided. In one approach, an “ejector” lever is provided. In a locked position, a cam portion of the lever arm extends into a detent in the chassis, locking the modular component securely into place. In an unlocked position, the cam portion does not extend into the detent, thereby making it possible to slide the modular component into or out of a position in the chassis.  
           [0005]    [0005]FIG. 1A shows a frontal view of a chassis  100  configured to receive a modular component (not shown). The chassis  100  comprises a frame  102 , the front of which is shown in FIG. 1A. The frame  102  is formed in such a way as to leave an opening  104  into which a modular component may be inserted. FIG. 1B shows a top sectional view of the chassis  100  in the plane indicated by the arrows “A” in FIG. 1A. FIG. 1B shows the frame  102  comprising a left detent  106  and a right detent  108 , such as may be provided to receive the cam portion of the ejector lever described above.  
           [0006]    [0006]FIG. 2A shows a typical prior art modular device  200 . The modular device  200  comprises a modular component  202  having a face plate  230 , a left ejector lever  204  attached to a left lever support  206  in a manner that permits the lever  204  to be rotated as indicated by the arrow  208  about an attachment point  210 . The modular device  200  further comprises a right ejector lever  212  attached to a right lever support  214  in a manner that permits the lever  212  to be rotated as indicated by the arrow  216  about an attachment point  218 . In the position shown in FIG. 2A, the ejector levers  204  and  212  are in an unlocked position and would not impede the insertion or extraction of the modular device  200  from a chassis, such as the chassis  100  of FIGS. 1A and 1B. FIG. 2B shows the levers  204  and  212  after they have been rotated into a locked position. In this locked position, the lever  204  can be seen to comprise a cam portion  220  and the lever  212  to comprise a cam portion  222 . In one typical configuration, the cam portion  220  and cam portion  222  would in the position shown in FIG. 2B extend into a detent in the chassis frame, such as the detents  106  and  108  of FIG. 1B. The arrows in FIG.  2 B show the direction in which the lever arms  204  and  212  would be rotated to return them to the unlocked position shown in FIG. 2A.  
           [0007]    A problem that may arise with the above-described approach to locking a modular component into a chassis or other frame is that the non-cam portion of the ejector lever arm may block access to a portion of the face plate of the modular component when the component has been installed and the lever arm(s) is(are) in the locked position. In FIG. 2B, for example, in the locked position shown the lever arms  204  and  222  block viewing of and access to portions of the face plate  230  of the modular component  202 . As such, in the locked position the lever arms may interfere with the viewing of indicator lights or other displays, and may interfere with the removal or insertion of cables or modular subcomponents that the modular component  202  may be configured to receive, such as the swapping of media daughter access (MDA) modules in a network switch input/output (I/O) module installed in a network switch chassis.  
           [0008]    Therefore, there is a need for a way to provide for the locking and ejection of modular components from a chassis that does not result in a lever arm or other structure being in a position that would block viewing of and/or access to the face plate of the modular component.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    Various embodiments of the invention are disclosed in the following detailed description and the accompanying drawings.  
         [0010]    [0010]FIG. 1A shows a frontal view of a chassis  100  configured to receive a modular component (not shown).  
         [0011]    [0011]FIG. 1B shows a top sectional view of the chassis  100  in the plane indicated by the arrows “A” in FIG. 1A.  
         [0012]    [0012]FIG. 2A shows a typical prior art modular device  200 .  
         [0013]    [0013]FIG. 2B shows the levers  204  and  212  after they have been rotated into a locked position.  
         [0014]    [0014]FIG. 3A shows a cam and lever ejector assembly comprising a cam  302  and a lever  304 .  
         [0015]    [0015]FIG. 3B shows the cam and lever ejector assembly  300  in the locked position.  
         [0016]    [0016]FIG. 4A shows a cam and lever ejector assembly  400  comprising a cam  402 , a lever  404 , and an idler gear  406  interposed between the two.  
         [0017]    [0017]FIG. 4B shows the lock portion of the cam  402  extending into the corresponding detent in the chassis  420 .  
         [0018]    [0018]FIG. 4C shows an alternative configuration for the cam  402 , lever  404 , and idler gear  406 , which results in a more compact configuration.  
         [0019]    [0019]FIG. 5 shows the cam and lever ejector assembly  300  of FIGS. 3A and 3B as employed in one embodiment.  
     
    
     DETAILED DESCRIPTION  
       [0020]    The invention can be implemented in numerous ways, including as a process, an apparatus, a system, a composition of matter, a computer readable medium such as a computer readable storage medium or a computer network wherein program instructions are sent over optical or electronic communication links. In this specification, these implementations, or any other form that the invention may take, may be referred to as techniques. In general, the order of the steps of disclosed processes may be altered within the scope of the invention.  
         [0021]    A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.  
         [0022]    A cam and lever ejector assembly is disclosed. In one embodiment, the lever portion of the ejector assembly has been decoupled from the cam portion of the assembly. In one embodiment, a gear mechanism is used to transmit force from the lever to the cam, in such a way that the lever portion does not block access to the front of the modular component when the ejector assembly is in the installed and locked position.  
         [0023]    [0023]FIG. 3A shows a cam and lever ejector assembly comprising a cam  302  and a lever  304 . The cam  302  comprises a toothed portion  306  that includes a plurality of gear teeth and a control member  308 . The lever  304  comprises a toothed portion  310  configured and positioned to engage the toothed portion  306  of the cam  302  as shown. In the position shown, the cam and lever ejector assembly is in the unlocked position, in which the control member  308  of the cam  302  is retracted, thereby ensuring that the cam  302  does not interfere with the insertion or extraction of the component  314  from a chassis or other frame. In this unlocked position, the lever  304  is in a position that may block access to a portion of the faceplate  312  of the component  314 , but that condition typically would be acceptable for periods during which the component  314  is being inserted into or extracted from a chassis.  
         [0024]    [0024]FIG. 3B shows the cam and lever ejector assembly  300  in the locked position. The lever  304  has been rotated about its pivot point  307 , to the position shown, which has resulted in the cam  302  being rotated into a locked position by interaction of the toothed portion  310  of lever  304  with the toothed portion  306  of cam  302 . The pivot point  307  is fixed in relation to the component  314  and the lever  304  is rotatably mounted to the component  314  (or some structure, such as a tab or extension, affixed to the component  314 ) at that point. Rotation of lever  304  into the position shown has caused the cam  302  to be rotated about its pivot point  309  into the position shown. Like pivot point  307 , pivot point  309  is fixed in relation to the component  314  and is the point at which the cam  302  is rotatably mounted to the component  314  (or some structure, such as a tab or extension, affixed to the component  314 ). In this locked position, the control member  308  of the cam  302  extends into a detent in the chassis  340 , thereby preventing the modular component  314  from being extracted. In the locked position shown, the lever  304  is in a position that does not block access to the faceplate  312  of the modular component  314  (compare FIG. 3A), which would permit the viewing of indicators and displays and the swapping of cables or modular subcomponents, as applicable, during times when the modular component  314  is in the installed and locked position. In one embodiment, the respective toothed portions of the cam  302  and the lever  304  are configured to provide a mechanical advantage, thereby enabling the lever  304  to be shorter than otherwise would be necessary, with the result that the lever  304  does not extend too far out from the faceplate of the modular component when the modular component is in the installed and locked position, as shown in FIG. 3B.  
         [0025]    While in certain of the embodiments shown and described in detail herein a gear mechanism is used to cause the cam to rotate in response to movement of the lever, other mechanisms for transmitting force generated by rotating the lever  304  about its pivot to cause the cam  302  to rotate about its pivot into the locked or retracted position, as applicable, may be used.  
         [0026]    [0026]FIGS. 4A and 4B show a variation on the cam and lever ejector assembly shown in FIGS. 3A and 3B in order to reverse the position of the lever in the locked and unlocked positions. FIG. 4A shows a cam and lever ejector assembly  400  comprising a cam  402 , a lever  404 , and an idler gear  406  interposed between the two. The toothed portion of the lever  404  engages the idler gear  406  at one point, and the toothed portion of the cam  402  engages the idler gear  406  at a second point, such that rotation of the lever  404  in the direction of arrow  408  causes the idler gear  406  to rotate in the clockwise direction, which in turn causes the cam  402  to rotate in the counterclockwise direction. In one embodiment, the position shown in FIG. 4A corresponds to the unlocked position, in which the lock portion of the cam  402  does not extend into the corresponding detent in the chassis (compare FIG. 3A). In one embodiment, moving the lever  402  in the direction of arrow  408  until the lever arm  402  is aligned with the faceplate of the modular component causes the cam  402  to be rotated into the locked position, as shown in FIG. 4B. FIG. 4B shows the lock portion of the cam  402  extending into the corresponding detent in the chassis  420 . While the configuration shown in FIGS. 4A and 4B results in the lever  404  blocking at least a portion of the faceplate of the associated modular component when the component is in the installed and locked position, in one embodiment the mechanical advantage provided by the gear mechanism makes it possible to use a shorter lever  404 , such that less of the face plate is blocked than would have been blocked by using a typical prior art ejector assembly, such as those shown in FIGS. 2A and 2B.  
         [0027]    [0027]FIG. 4C shows an alternative configuration for the cam  402 , lever  404 , and idler gear  406 , which results in a more compact configuration. The cam and lever assembly  400  is shown in FIG. 4C in the unlocked position. Rotating lever  404  in the direction of arrow  422  would cause the cam  402  to be rotated counterclockwise into the locked position, similar to that shown in FIG. 4B.  
         [0028]    [0028]FIG. 5 shows the cam and lever ejector assembly  300  of FIGS. 3A and 3B as employed in one embodiment. A modular assembly  500  comprises a planar horizontal body portion  504  and a vertically oriented faceplate  502 . The faceplate  502  includes a display  506 , a variety of cable receptacles  508 , and a plurality of modular subcomponents  510 . The left side cam and lever ejector assembly  300  of the modular assembly  500 , labeled  300 L in FIG. 5 for clarity, is shown in the locked position (compare FIG. 3B), whereas the right side cam and lever ejector assembly  300  of the modular assembly  500 , labeled  300 R, is shown in the unlocked (cam retracted) position (compare FIG. 3A). As FIG. 5 shows, in the locked position left side ejector assembly  300 L does not obscure the faceplate  502  of modular assembly  500  and, as a result, does not obscure the display  506 . By contrast, if the right side cam and lever ejector assembly  300 R were in the locked position in the position as shown in FIG. 5, instead of the unlocked position, the lever would obscure the rightmost modular subassembly  510 , possibly preventing, e.g., that modular subassembly from being inserted, extracted, or otherwise serviced or accessed (e.g., by connecting or disconnecting a cable, reading an indicator, etc.) while the modular assembly  500  is locked in place.  
         [0029]    In one embodiment, use of a cam and lever ejector assembly such as described herein has the further advantage of reducing the risk of harm to the modular component or adjacent structures or individuals due to potentially harmful emissions by reducing the size of the cut out needed in the faceplate of the modular component to accommodate the ejector assembly. In addition, in one embodiment use of a cam and lever ejector assembly such as described herein avoids the need to extend the chassis forward beyond the faceplate of the modular component to allow the cam portion of the assembly to extend into the detent in the chassis without having a large cut out in the faceplate, such as shown in FIGS. 2A and 2B. Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention. The disclosed embodiments are illustrative and not restrictive.