Abstract:
A module latching system and method provides a removable engagement between a module and a main body of an instrument, wherein removal is accomplished by depressing at least two spaced apart actuation points to disengage biased latch members between the module and main body. The module release actuation points are positioned and spaced so as to substantially simultaneously urge the module to move in a release direction as the latch members are disengaged.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to test instruments, and more particularly to a latch system and method for ensuring reliable but removable engagement of a removably installable test instrument module.  
         [0002]     Often, a test instrument may provide for optional modules to be installed in order to provide different functionality to the instrument. This raises the need for a manner to allow the modules to be easily installed or removed. However, it may be important or desirable to ensure that the module is not inadvertently removed, for example, during a testing operation. It is desired that some manner be provided to allow relatively easy insertion or removal of the module, while ensuring that the module is not too easily removed so as to result in accidental or unintentional removal.  
       SUMMARY OF THE INVENTION  
       [0003]     In accordance with the invention, a module latch system is provided with at least two independently activated latch release actuator positions in spaced relation, whereby the likelihood is low of both actuator positions being inadvertently activated in substantially simultaneous fashion.  
         [0004]     Accordingly, it is an object of the present invention to provide an improved system for removably latching a module to a test instrument.  
         [0005]     It is a further object of the present invention to provide an improved method of releasably engaging a removable module in a test instrument.  
         [0006]     It is yet another object of the present invention to provide an improved test instrument that includes a removable module latching system that enables a module to be inserted and removed to the instrument, while reducing the likelihood that the module will be inadvertently removed or released.  
         [0007]     The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view of a test instrument with a removable module, employing the latch system and method according to the invention;  
         [0009]      FIG. 2  is a perspective view of the test instrument and module of  FIG. 1 , with the module removed from the test instrument;  
         [0010]      FIG. 3  is an exploded perspective view of the module;  
         [0011]      FIG. 4  is a partial cross-sectional view of one of instrument/module with the latch engaged; and  
         [0012]      FIG. 5  is a partial cross sectional view of the instrument/module showing the latch as being disengaged. 
     
    
     DETAILED DESCRIPTION  
       [0013]     The system according to a preferred embodiment of the present invention comprises a latch system and method to allow a module to be removably but securely engaged by a test instrument. The configuration of the latch system and release mechanism is such as to reduce the likelihood of the module being inadvertently or accidentally removed from the instrument, which may be detrimental or inadvisable while the instrument is in operation or use.  
         [0014]     Referring now to  FIG. 1 , a perspective view of a test instrument with a removable module installed therein, the instrument  10 , which comprises a network test instrument in a particular embodiment, includes a main body portion  12  and a removable module portion  14  which is received by the main body portion and can provide additional or optional test capabilities for the instrument. The view in  FIG. 1  is of the bottom of the instrument. The module  14  has a pair of latch actuator buttons  16  in space relation to one another near left and right edges of the module body, positioned toward the rear most portion of the module (that is, the portion of the module that extends most deeply into the mail body portion). Various openings  18 ,  18 ′,  18 ″ and  18 ′″ for receiving connectors or the like are positioned at the outermost face of the module, suitable to receive network cable jacks or other connectors therein to enable interface to a network or system under test. These connectors can comprise, for example, RJ45 type connections, fiber optic connections, or other connections dependent on the type of system or network test or test functionality that the module is providing.  
         [0015]     Referring to  FIG. 2 , which is a perspective view of the test instrument and module of  FIG. 1 , with the module removed from the test instrument, the main body  12  includes a defined space  20  sized and adapted to receive the module  14  therewith, and includes a pair of module engaging posts  22  at left and right side walls thereof, which are suitably engaged by corresponding slots  24  on each corresponding sides of the module  14 , to secure the outer end of the module relative to the main body.  
         [0016]     Toward the innermost end of the space  20 , are a pair of latch members  26 ,  26 ′, which have a raised portion  28  which extends above the plane of the face  30  of the space  20 . The latch members are flexible and biased such that the end of the latch member with raised portion  28  is capable of being depressed downwardly relative to the plane of face  30  but will return upwardly when released or when not otherwise depressed. Suitably, the latch members are defined as a portion of the same material as forming face  30 , by providing cut out portions  32  along 3 sides of the latch member, leaving the 4 th  side still attached as part of face  30 . A preferred material is plastic.  
         [0017]     Referring now to  FIG. 3 , an exploded perspective view of the module as viewed from the opposite face thereof as in  FIGS. 1 and 2 , it may be observed that the module is suitably formed as box-like structure, being somewhat curved on the back face portion  14 A thereof (relative to the view of  FIG. 3 ). A second face portion  14 B fits together with portion  14 B, to form the module and may be held together with screws, for example, to enable disassembly thereof. In a test instrument configuration, the interior space of the module will hold circuitry and interface connectors to provide the functionality that the module provides to the test instrument. An opening  34  is defined by cut out portions of the module, and suitably enables a connector or jack to be accessed for engaging a corresponding jack or connector that is positioned at a correspondent opening  36  in the main body  12  (see  FIG.2 ).  
         [0018]     The pair of actuator buttons  16  are formed as the distal ends of latch actuators  38 , comprising buttons  16 , radial flange portions  40  of slightly wider diameter than the buttons  16 , elongate extension portions  42  and front and rear slots  44  at the ends of portions  42  most distal from the buttons  16 .  
         [0019]     The distal ends of the portions  42  are, when the module face portions  14 A and  14 B are assembled, received into openings  46  in face portion  14 B, the openings having corresponding members  48  that correspond with slots  44  as discussed in conjunction with  FIG. 4  and  FIG. 5  hereinbelow.  
         [0020]     The buttons  16  are received through openings  52  in fact portion  14 A, the openings being of a lesser diameter than the diameter of radial flanges  40 , but of larger diameter than buttons  16 .  
         [0021]     Now, referring to  FIG. 4 , a partial cross-sectional view of one of instrument/module with the latch engaged, and to  FIG. 5 , the partial cross sectional view as in  FIG. 4 , but showing the operation of the latch being disengaged, the outer surface of the button  16  is somewhat curved, as are the faces of the module  14 B and the main body  12 . The wider diameter of radial flange  40  cooperates with the intermediate diameter of opening  52  to keep the latch actuator  38  from falling out of the module body via the opening  52 , while the narrower diameter of the button portion  16  relative to the opening allows movement upwardly and downwardly. At the lower end (relative to the orientation of  FIG. 4 , of actuator  38 , members  48  as defined in face  14 A of the module fit within slots  44 , enabling up and down movement of the actuator relative to the face  14 A, but the cooperation of the members and slots result in a downward endpoint of movement being defined by the end of the slot at shoulder portion  50 .  
         [0022]     The main body  12  includes an overhanging portion  12 A, while the module includes a corresponding extended portion  14 C that is somewhat indented so that when the module is fully inserted into the main body, the portions  12 A and  14 C cooperate as is visible in  FIG. 4  to provide a good fit between the module and main body. When the module is fully inserted into the main body, the raised portion  28  of the latch  26 , is received by opening  46  and the upward bias (relative to the view of  FIG. 4 ) of the latch results in the latching of the module into the main body.  
         [0023]     In  FIG. 5 , the operation of releasing the latch to remove the module is shown. If the user of the instrument wishes to remove the module, the user depresses both buttons  16  in the direction of arrow  54 , which causes the downward movement of the latch actuators  38  and the bottom most ends thereof pushes against the raised portions  28  of the latches to move them out of engagement with openings  46 , so the module is no longer latched and can be slid out of engagement with the main body in the direction of arrow  56 .  
         [0024]     By employing two such latches in spaced relation as show in the illustrated embodiment, the user is unlikely to inadvertently remove the module from the main body, as both latch buttons  16  must be depressed at the same time in order for the module to release. Further, the somewhat curved configuration of the module and the main body in the region where they interface and the curved profile of the button faces (observable in  FIGS. 4 and 5 ) result in the natural movement of the module in the direction of arrow  56  when the buttons are being depressed. A preferred manner of actuation the buttons is by grasping the instrument with both hands such that the bottom face thereof is facing the user, and depressing the buttons with the left and right thumbs. This enables a rather natural and ergonomic motion of pushing the module out of engagement with the main body with the same depressing motion of the thumbs.  
         [0025]     Accordingly, an improved latch system and method is provided for enabling a removable module to be engaged by a main body of a test instrument, with features to reduce the likelihood that the module will be accidentally released from the main body. The configuration and shape gives a natural manner of releasing the latch system and removing the module from engagement.  
         [0026]     While a preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.