Abstract:
A pressing machine ( 10 ) for combining metal members ( 16 ) and plastic members ( 14 ) of shield assembles ( 12 ) includes a workbench ( 60 ), a cylinder ( 54 ), a guide device ( 100 ), and a pressing device ( 200 ). The workbench defines channels ( 70 ) for receiving the corresponding plastic members thereon. The pressing device includes two pressing blocks ( 220 ) defining cross indentions ( 228 ) for receiving protrusions formed in the plastic members to allow the metal members to be downwardly pressed thereby causing the cross cuts defined in the metal member to engage with the cross protrusions of the plastic member, and a pressing bar ( 222 ) forming pressing feet ( 232 ) for downwardly pressing inclined plates ( 40 ) formed in the metal members to allow apertures ( 42 ) defined in the inclined plates to engage with projections ( 24 ) formed in the tabs ( 22 ) of the plastic members.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a shield assembly for a computer enclosure and a pressing machine for making the shield assembly, and particularly to a shield assembly for ready attaching to a computer enclosure and a pressing machine for pressing the shield assembly together. 
     2. Related Art 
     A support bracket in a computer enclosure often defines a number of cavities for accommodating data storage devices therein. A front panel of the computer enclosure accordingly defines a number of openings for insertion of the data storage devices. A number of metal shields is attached in the openings of the front panel, to prevent electromagnetic radiation generated by the computer from coming out of the computer. Such metal shields are commonly integral with the front panel. When a data storage device is required to be installed, a metal shield is removed from the front panel using a tool. 
     However, removing this kind of metal shield from the front panel with a tool is unduly inconvenient. Furthermore, the metal shield cannot be reused. Thus when a data storage device is removed from the support bracket, the opening of the front panel cannot be covered back over again with the shield. This allows electromagnetic radiation to come out of the computer, or necessitates use of a replacement shield. 
     It is strongly desired to provide a shield assembly for a computer enclosure which overcomes the above problems encountered in the related art. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a shield assembly for covering an opening defined in a computer enclosure, to prevent electromagnetic radiation from coming out of the computer. 
     Another object of the present invention is to provide a pressing machine which can readily make the shield assembly. 
     To achieve the above-mentioned objects, a shield assembly of the present invention comprises a plastic member and a metal member attached on the plastic member. The plastic member forms a tab with a projection and a plurality of cross protrusions. The metal member has a gap for extension of the tab therethrough, an inclined plate defining an aperture for engaging with the projection to prevent the metal member from moving relative to the plastic member in a vertical direction, and a plurality of cross cuts for engaging with the cross protrusions to prevent the metal member from moving relative to the plastic member in a horizontal direction. 
     The pressing machine for combining the metal member and the plastic member of the shield assembly together comprises a workbench, a cylinder, a guide device, a pressing device and a coupling bar connected between the cylinder and the pressing device. The workbench comprises a position board defining a plurality of channels for receiving the corresponding plastic members thereon. The pressing device comprises a pair of pressing blocks and a pressing bar between the pressing blocks. Each pressing block defines a plurality of cross indentions for receiving the protrusions of the plastic members. This allows the metal member to be downwardly pressed, thereby causing the cross cuts of the metal member to engage with the cross protrusions of the plastic member. The pressing bar comprises a plurality of pressing feet for downwardly pressing the inclined plates of the metal members, to allow the inclined plates to engage with the projections of the plastic member in the apertures thereof. 
     Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an assembled view of a shield assembly in accordance with the present invention; 
     FIG. 2 is an enlarged view of the circled portion II of FIG. 1; 
     FIG. 3 is a perspective view of a pressing machine for combining the shield assembly of FIG. 1; 
     FIG. 4 is a perspective view of a base of a guide device of the pressing machine of FIG. 3; 
     FIG. 5 is a perspective view of a pressing block of FIG. 3; 
     FIG. 6 is a bottom planar view of FIG. 5; and 
     FIG. 7 is a perspective view of a pressing bar of FIG.  3 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, a shield assembly  12  in accordance with the present invention comprises a plastic member  14  and a metal member  16  attached on an inner side of the plastic member  14 . 
     The plastic member  14  is rectangular. A tab  22  extends upwardly from a central portion of the inner side of the plastic member  14 . A projection  24  is formed on one side wall of the tab  22 . Four cross protrusions  20  respectively extend upwardly from the inner side of the plastic member  14 , two on each side of the tab  22 . A pair of spaced fasteners  26  extends upwardly from one end of the inner side of the plastic member  14 . A pair of hooks  28  extends upwardly from the other end of the inner side of the plastic member  14 , opposite to the fasteners  26 . Four cross cuts  34  are defined in the metal member  16  for receiving the four cross protrusions  20  of the plastic member  14 , to prevent the metal member  16  from moving relative to the plastic member  14  in a horizontal direction. A gap  38  is defined in a central portion of the metal member  16 , for extension of the tab  22  of the plastic member  14  therethrough. An inclined plate  40  extends from an edge of the metal member  16 , adjacent the gap  38 . An aperture  42  is defined in a free end of the inclined plate  40  for receiving the projection  24  of the plastic member  14 , to prevent the metal member  16  from moving relative to the plastic member  14  in a vertical direction. A pair of first arms  48  extends from one end of the metal member  16 . A first cutout  46  is defined between the pair of first arms  48 . Each first arm  48  defines a cutaway  50  in a free end thereof, for extension of the corresponding fastener  26  of the plastic member  14  therethrough. A pair of second arms  58  extends from the other end of the metal member  16 . A second cutout  56  is defined between the pair of second arms  58 . Each second arm  58  defines a hole  59  therein, for extension of the corresponding hook  28  of the plastic member  14  therethrough. 
     In use, the shield assembly  12  is embedded in an opening defined in a front panel of a computer enclosure (not shown). The fasteners  26  and the hooks  28  of the shield assembly  12  are respectively engaged with the computer enclosure. The first and second arms  48 ,  58  are resiliently retained against the enclosure such that the metal member  16  covers the opening. Thus electromagnetic radiation is prevented from coming out of the opening. 
     Referring to FIG. 3, a pressing machine  10  combines corresponding metal members  16  and plastic members  14  together to form shield assemblies  12  of the present invention. The pressing machine  10  comprises a cylinder  54 , a workbench  60 , a guide device  100 , a pressing device  200 , and a coupling bar  205  connected between the cylinder  54  and the pressing device  200 . 
     The workbench  60  comprises four side walls  62  and a top wall  64  disposed on the four side walls  62 . A mounting board  66  is secured on the top wall  64 . A position board  68  is mounted on the mounted board  66 . A plurality of channels  70  is defined in a top surface of the position board  68 , for receiving the plastic members  14  of the shield assemblies  12 . Three through holes  72  are defined in a front portion of the top wall  64  of the workbench  60 , for mounting three buttons  74  therein. A pair of support plates  76  is secured on a rear portion of the top wall  64 , opposite to the buttons  74 . A vertical plate  78  is connected between side walls of the pair of the support plates  76 , forming a space (not labeled) for receiving a control circuit (not shown) therein. 
     Referring also to FIG. 4, the guide device  100  comprises a base  110 , a pair of guide bushings  112 , and a pair of guide posts  114 . A recess  116  is defined in a central portion of a top surface of the base  110 , forming a pair of shoulders  124  on opposite sides of the recess  116 . A passageway  118  is defined in the base  110 , below the recess  116 . Four first shoulder holes  120  are defined in the base  110 , below the recess  116  and around the passageway  118 . Each shoulder  124  forms a connecting portion  126  extending upwardly from one end thereof. A second shoulder hole  130  is defined in each shoulder  124 . Each connecting portion  126  defines a screw hole  128 , for extension of a bolt (not shown) therethrough to engage with the vertical plate  78  and thereby secure the base  110  on the workbench  60 . 
     The cylinder  54  is secured on the base  110  with a chassis (not labeled) thereof received in the recess  116 . Four screws  122  are extended through the shoulder holes  120  of the base  110  to engage with threaded holes (not labeled) defined in the cylinder  54 . The guide bushings  112  interferentially engage with the base  110  in the second shoulder holes  130 . The guide posts  114  respectively extend through the corresponding guide bushings  112 . 
     Referring also to FIGS. 5-7, the pressing device  200  comprises a connecting plate  210 , a bottom plate  212 , a pair of pressing blocks  220 , and a pressing bar  222 . The connecting plate  210  is secured on a top surface of the bottom plate  212 . The guide posts  114  of the guide device  100  are secured on opposite sides of the connecting plate  210 . The pressing bar  222  is secured under a central portion of a bottom surface of the bottom plate  212 . The pair of pressing blocks  220  is respectively secured under the bottom surface of the bottom plate  212 , on opposite sides of the pressing bar  222 . Each pressing block  220  defines a longitudinal groove  224  in a center of a bottom surface thereof. A plurality of spaced slots  226  is defined in the bottom surface of the pressing block  220 , perpendicular to the longitudinal groove  224 , thereby forming a plurality of cross indentions  228 . A pair of stanchions  230  is formed on opposite sides of the bottom surface of the pressing block  220 . The pressing bar  222  forms a plurality of press feet  232 , corresponding to the channels  70  of the position board  68 . 
     In operation, the plastic members  14  of the shield assembly  12  are respectively placed on the channels  70  of the position board  68 . The corresponding metal members  16  are placed on the plastic members  14 , with the cross cuts  34  of the metal members  16  above the corresponding cross protrusions  20  of the plastic member  14 . The fasteners  26  of the plastic members  14  respectively extend through the corresponding cutaways  50  of the metal members  16 , and the hooks  28  of the plastic members  14  extend through the corresponding holes  60  of the metal members  16 . The power supply button of the buttons  74  is then turned on. The coupling bar  205  is pushed downwardly by air pressure of the cylinder  54 . The pressing device  200  is accordingly downwardly moved. The cross indentions  228  of the pressing block  220  respectively receive the corresponding cross protrusions  20  of the plastic member  14  therein, and the bottom surface of the pressing block  220  downwardly presses the metal members  16  near the cross openings  340  of the metal members  16 . The press feet  232  of the pressing bar  222  respectively downwardly press the inclined plates  40  of the metal members  16 , thereby causing the inclined plates  40  to downwardly snap on the corresponding projections  24 . The coupling bar  205  continues to move downwardly until the stanchions  230  of the pressing block  220  abut the position board  68  of the workbench  60 . At this time, the cross protrusions  20  of the plastic members  14  are completely received in the cross cuts  34  of the metal members  16 , and the apertures  42  of the metal member  16  engage with the projections  24  of the plastic member  16 . 
     It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.