Abstract:
The present invention provides a latch mechanism which is adapted to secure a computer component to a chassis; the mechanism includes a base that is attached to the computer component, a latch handle pivotably mounted on the base, the latch handle being capable of pivoting away from the base. An actuator arm is pivotably mounted to the latch handle so that when the latch is pivoted away from the base, the actuator arm will also move away from the base. A cam plate is also pivotably mounted on the base and is capable of rotating with respect to the base. The cam plate includes at least one notch adapted to cooperate with the chassis so that as the cam plate is rotated, the notch selectively engages and disengages with the chassis.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a latch; more specifically the present invention relates to a latch that can be used to secure a computer component into a chassis.  
           [0002]    Latches have been used extensively for securing, or latching, one thing to another. In every context people are confronted with different latches which are designed to solve particular problems in a variety of situations. For example, latches that open and close a car door have certain latching characteristics which are necessary for the application. The latch must be secure and reliable, it must be able to close and latch using a varied applied force, etc.  
           [0003]    Other latches may be designed for decorative purposes and provide the user with an aesthetically pleasing latch. It is often important that a latch which is used frequently include features which provide an ergonomically comfortable opening and closing mechanism. Typically, the ergonomically designed latch should be easy and comfortable to use.  
           [0004]    In the computer industry there has been an increasing usage of computer chassis systems to which multiple computer housings may be inserted.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention provides a latch mechanism which is adapted to secure a computer component to a chassis; the mechanism includes a base that is attached to the computer component, a latch handle pivotably mounted on the base; and the latch handle is capable of pivoting away from the base. An actuator arm is pivotably mounted to the latch handle so that when the latch is pivoted away from the base into an unlatched position, the actuator arm will also move away with respect to the base. A cam plate is also pivotably mounted on the base and is capable of rotating with respect to the base. The cam plate includes at least one notch adapted to cooperate with the chassis so that as the cam plate is rotated, the notch selectively engages and disengages with the chassis to secure the computer housing to the base.  
           [0006]    The latch of the present invention may further include a locking plate that is adapted to seat against the cam plate when the cam plate is in a secured position and prevent the cam plate from moving. The locking plate may also include a surface which cooperates with the actuator arm to unlock the cam plate and permit the cam plate to rotate. The latch mechanism may also include a spring that is mounted on the locking arm at one end and the base at the other, wherein the spring biases the locking arm toward the cam plate. The actuator arm may include a pin that forces the locking arm to move when the latch handle is pulled.  
           [0007]    The cam plate may include two notches and the chassis has two securement pins which are adapted to fit within the cam plate notches to secure the computer housing to the chassis. The cam plate may include a slot which cooperates with a pin at the distal end of the actuator arm so that when the latch handle is pulled, the pin causes the cam plate to move in the counter clockwise direction.  
           [0008]    In another embodiment, the present invention relates to a latch mechanism for attaching a housing to a chassis featuring a latch handle pivotably mounted to a base, an actuator arm pivotably mounted to the latch at one end, a cam plate pivotably mounted on the base and adapted to selectively latch and unlatch the mechanism, the cam plate including at least one notch to secure the cam plate to the chassis, wherein the other end of the actuator arm cooperates with the cam plate to selectively lock and unlock the latch mechanism.  
           [0009]    The cam plate may further comprise a slot and the distal end of the actuator arm may comprise a pin, wherein the pin cooperates with the slot to move the cam plate. The latch mechanism may include a locking arm that is pivotably mounted to the base, wherein the locking arm cooperates with the cam plate to lock the cam plate against rotation when the latch is in the second position. The locking arm may include a surface against which the actuator arm can move so that when the latch handle is pulled, the actuator arm moves the locking arm so that the cam plate can rotate. The actuator may further include a pin which moves against the actuator surface which moves the locking arm and the locking arm may be biased toward engagement with the cam plate by a spring.  
           [0010]    The cam plate of the latch mechanism may be biased for counter clockwise rotation by a spring. The spring which biases the cam plate may be a rotational spring that is mounted on at the pivot point of the cam plate.  
           [0011]    Accordingly, the present invention provides a latch which automatically latches as the housing is inserted so that all the user need do is push the housing into the chassis to secure the housing in the chassis. The automatic latching feature can provide some significant advantages to a computer processing chassis system. First, an operator need only push the processor into the chassis and does not have to coordinate a latching operation. Moreover, the automatic latch feature provides a quicker, more efficient operation. The processor slides into the locking position by rails which guide and align the processor.  
           [0012]    The invention also provides a latch which can unlock with minimal force required to pull the latch to unlock the computer housing from the chassis. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0013]    [0013]FIG. 1 is a view of a chassis with computer housings attached;  
         [0014]    [0014]FIG. 2A is a partial view of the chassis with detail about the actuator tabs;  
         [0015]    [0015]FIG. 2B is a detail view of the actuator tabs and a cam plate within the latch;  
         [0016]    [0016]FIG. 3 is a top view of the latch of the present invention;  
         [0017]    [0017]FIG. 4 is an exploded view showing the various components of the latch;  
         [0018]    [0018]FIG. 5 shows a partial cut away view of the latch partially inserted into the housing;  
         [0019]    [0019]FIG. 6 shows a partial cut away view of the latch partially inserted into the housing;  
         [0020]    [0020]FIG. 7 shows a partial cut away view of the latch partially inserted into the housing. 
     
    
     DETAILED DESCRIPTION  
       [0021]    [0021]FIG. 1 shows a chassis  2  which houses multiple computer components or housings  4 . The chassis is about 84 inches tall, 24 inches wide and 30 inches deep. The chassis is adapted to contain multiple computer housings which are generally rectangular boxes about 20 inches wide, 2-8 inches high and 20 inches deep. The computer housings contain processors (not shown) and switches (also not shown) sufficient for the operation of the system. Each housing is connected to the chassis via a data and power connection (not shown) which is described in detail in co-pending application (Attorney Docket number 112153-121, entitled “Simplified Power and Data Connector for Use with Chassis Systems that House Multiple Processors”) which is incorporated by reference.  
         [0022]    The latch  6  allows the computer housing to be secured within a corresponding slot in the chassis once the computer housing is inserted into the chassis. FIG. 2A shows a detailed view of the latch as it secures the computer housing to the chassis (shown in phantom). As illustrated, a cam plate (described in detail below) in the latch  6  interacts with two latch posts  8 ,  10  and causes the latch to close and become secured. As the cam plate is rotated it drives the component in or out of the chassis. The operation of the latch posts and the latch will become apparent as the components of the latch are described.  
         [0023]    [0023]FIGS. 3 and 4 are a top view of the latch and an expanded view of the latch components, respectively. The latch components are supported by a generally rectangular base  30 . The latch includes a face portion  32  which is positioned at the right side of the outwardly facing side of the computer housing or chassis  2 . The front part of the base  30  is adapted to mate with a cover  34  by screws  36  and  38 . The base  30  and the cover  34  cooperate to form a recess  40  which is adapted to fit a latch handle  42 . As shown in FIG. 3, when the latch handle  42  is in its secured position, it is positioned entirely within the recess  40 . The latch handle is pivotably mounted to the base  30  and cover  34  by a pin  46  which is secured into an aperture  48 . The pin is positioned in an aperture  54  in the bottom of the cover and another aperture (not shown) in the top cover  34 . The pin is able to pivot within the apertures. Sleeves  56  may be provided to provide a tight tolerance between the pin  46  and the apertures.  
         [0024]    The recess  40  and the latch handle  42  are ergonomically designed and allow several fingers to be inserted into the recess and pull on the latch handle so that the latch handle pivots on the pin to a position about 45°. The inner surface (not shown) of the latch handle has a smooth curved finish to enhance the comfort of the user pulling the latch handle to unlatch the computer housing from the chassis.  
         [0025]    The latch handle  42  includes an aperture  58 , shown in phantom in FIG. 3, which is located off-set from the latch handle approximately 0.5 inches (1.25 cm). An actuator  60  is pivotably mounted to the latch by an actuator pin  62 . The actuator pin is secured in place by a washer  64  and a clip  66 . The actuator arm is pivotable about the pin in a range that allows the latch arm to swing out. The actuator arm extends through a recess  68  in the base toward the other components of the latch. The recess  68  is sufficiently sized to allow for swing movement of the actuator when the latch handle is pulled.  
         [0026]    The latching components are described below. In addition to the actuator arm  60 , a cam plate  70  cooperates with a locking arm  72  to secure the latch in a locked position. When in the locking position, the locking arm  72  prevents the cam plate  70  from rotating and secures the latch in place. When the locking arm is moved away, the actuator arm is free to move the cam plate so that the latch is unsecured.  
         [0027]    In more detail, and with continued reference to FIG. 4, the cam plate  70  is positioned on the right rear-ward location of the base and mounted in such a manner that the cam plate can rotate about a mounting pin  76 . The plate  70  is biased by a coil spring  78  which urges the plate toward the counter clockwise direction.  
         [0028]    The cam plate has several contours in its perimeter profile that are intended to perform various functions. Along the portion of the cam plate that is along the outboard side of the base, are two inward notches  80  and  82  which cooperate with securement arms shown as pins  8  and  10  (shown in FIG. 2) on the chassis. A radially extending projection  84  secures the cam plate against the latch posts so the computer housing does not move from the chassis. A notch  86  forms a recess on the inboard side of the cam plate  70  into which the locking arm  72  can fit when the cam plate is locked in place.  
         [0029]    The cam plate  70  also has an arcuate slot  88  formed in the plate on the side of locking notch  86 . The arcuate slot is adapted to receive a pin  92  which is fixed to the distal end  94  of the actuator  60 . The pin  92  is sized to slide within the groove in response to the motion of the cam plate and the actuator arm.  
         [0030]    The locking arm  72  of the latch mechanism is pivotably mounted on the base  30  by a screw  96 . The locking arm is able to pivot a sufficient range of motion so that the distal end  98  of the locking arm can engage with the cam plate  70  at the locking notch  86 . A portion of the distal end  98  of the locking arm  72  is bent 90° to create an interengagement location. This can be considered a “stop mechanism” since the locking arm engages (stops) the cam plate. In the preferred form, the angled portion extends upward about 0.4 inches.  
         [0031]    Intermediate the pivot attachment point  96  and the distal end  98  is an unlock actuator surface  102  which extends about 1 inch off a centerline created between the pivot pin  62  and the distal end which contains pin  92 . The surface  102  extends 90° from the locking arm and is bent away from the locking arm at bend  104  to form bend angle α. The preferred bend angle a is about 150°. The actuator arm  60  includes a pin  106  which is offset from the centerline which extends to and cooperates with the locking arm to unlock activation surface  102 . The locking arm has one side of a tension spring  108  attached, the other side of the spring is attached to the base. The spring biases the locking arm toward the cam plate. A retention plate  110  is attached to the base and secures the components in place.  
         [0032]    The locking sequence of the latch is described with reference to FIGS.  5 - 7 . FIG. 5 shows the lock as it is being inserted into the chassis as shown by arrow  120 . The notch  82  contacts the chassis-locking pin  8 . The pin  8  forces the cam plate  70  to rotate clockwise as shown by arrow  122  about the cam plate pin  76 . As the cam plate rotates, the activation pin  92  which slides within slot  88  as shown in FIGS.  5 - 7   a  is forced to the end of the slot designated  88   a  and, as the cam plate continues to rotate, the activation arm  60  is forced forward which causes the latch handle to pivot outward away from the base, as shown in FIG. 6. A tension spring  132  biases the actuator arm  60  toward the back of the base so that the cam plate rotates sufficiently to complete the movement of the pin  92  to the other end of slot  88  designated  88   b.    
         [0033]    [0033]FIG. 6 also shows the cam plate notch  80  engaging with pin  10 . The cooperation of the two pins permits the closing of the latch reliably with a minimal amount of space. The latch is secured in place by the locking arm  72  which is biased by a spring  108  to pivot toward the cam plate. As shown in FIG. 7, the distal end  98  of the locking arm  72  engages the notch  86  so that the latch is secured.  
         [0034]    The latch will stay secured until someone pulls on the latching arm. As someone pulls on the locking arm represented in FIG. 7 by arrow  124 , the actuator arm is pulled forward because of pin  62 . The movement of the actuator arm causes the pin  106  to slide against the locking plate  102  on the locking arm  72 . The contact between the plate  102  and the pin  106  causes the actuator arm  72  to pivot in a counter-clockwise direction as shown by arrow  126  so that the locking arm  72  moves away from the notch  86  in the cam plate  70 . The spring  78  causes the cam plate to rotate counter-clockwise and release the latch and allow the computer housing to be removed from the chassis.  
         [0035]    In connection with the automatic locking feature, the handle will project outward slightly during the engagement so that the person inserting the housing into the chassis is aware when the latch is about to lock on the housing. Once the latch is locked and the housing is secured in the chassis then the handle will be flush with the housing as shown.  
         [0036]    While this invention has been described with reference to particular embodiments, other and different devices, including those obvious to those skilled in the art, will embody the invention and are within the scope of the following claims.