Patent Publication Number: US-2012032380-A1

Title: PCB holder

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of Invention 
     The present invention relates to the field of the PCB holding devices during the PCB service by operator and machine. 
     2. Description of the Related Arts 
     Well known and widely used the variety of the PCB holders providing the PCB support with the various clamps attached to the PCB. For instance, alligator-type-clamp or groove-type-clamp attached to the PCB require significant amount of PCB surface along the edge to be occupied by the known clamps. 
     Other solutions are using a vacuum clamp for PCB holding—see U.S. Pat. No. 6,635,308. 
     The vise-type PCB holders are capable to hold PCB at the sides, but have rather long screw-driving vises attached to the PCB sides that makes difficult to service the parts soldered close to the edge. Also, vise-type holders require PCB to be tightened by screw each time when PCB goes out/in of the holder. 
     SUMMARY OF THE DISCLOSURE 
     The present invention is offering the solution where: 1) clamp does not occupy the PCB soldering surface; 2) PCB is holding by friction at PCB edge and at least one of next elements has to be a spring-type: holding rod-clamp, rod pad, and/or base plate; 3) holding PCB force is applied perpendicular to the PCB edge, but not to the top/bottom of PCB as in prototypes; 4) all holder parts attached to the PCB can be dielectric for PCB safe service; 5) PCB clamp design does not require the screw-type or similar devices for PCB engaging and release; 6) holder is capable to withstand a large vertical force applied to PCB; 7) offered PCB HOLDER is relatively simple in design and has all above advantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a PCB holder general view. 
         FIG. 2  shows a non-spring rod-clamp when PCB is not engaged. 
         FIG. 3  shows a non-spring rod-clamp when PCB is engaged. 
         FIG. 4  shows a spring rod-clamp. 
         FIG. 5  shows a spring rod-clamp when side force is applied. 
         FIG. 6  shows a holder having a rigid rod-clamp  3  fixed to the base  1  and sliding flexible rod-clamp  18  with attached permanent magnet  5 . 
         FIG. 7  shows a wire-spring-type clamp with a shoulder. 
         FIG. 8 ,  FIG. 9  and  FIG. 10  show the sequence of PCB engagement with a fixed rigid-rod-clamp  2  and a sliding-spring-rod-clamp  3  with magnet  5 . 
         FIG. 11 ,  FIG. 12  and  FIG. 13  show the sequence of PCB engagement with all fixed spring-rod-clamps. 
         FIG. 14  and  FIG. 15  show the sequence of PCB engagement with all sliding rigid-rod-clamps  5  attached to the spring base  1  by magnets  5 . 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
       FIG. 1  shows the PCB holder general assembly which includes: base  1  with attached rod-clamps  2  and  3 . Clamps  2  are rigid and permanently attached to the PCB by screws or welding. Clamp  3  is spring-type in radial direction and is capable to slide along the base  1  with a friction and said rod is attached to the ferromagnetic base  1  by a permanent magnet  5 . 
     Force and friction between the magnet  5  and base  1  must be strong enough to keep the PCB  4  fixed in place for a service, and weak enough to let the operator to slide the magnet  5  along the base  1 . Such friction magnet sliding is required for the rods adjustment to the specific PCB dimensions and shape. 
     PCB HOLDING ROD.  FIG. 2  shows the rod  3  having low-friction-sliding area  6  and high-friction-clamping area  7 . Low-friction area  6  provides easy PCB insertion into the clamping area  7 . High friction clamping area  7  keeps PCB  4  in place during the PCB service—see  FIG. 3 . 
     Initially, PCB sits in position as on  FIG. 2 . Then PCB slides down along the rod-clamp  3  and inclines the rod as on  FIG. 3 . PCB easy slides down along low friction surface  12 , which made, for instance, of nylon or polished steel. Continue sliding down, PCB reaches high friction clamping area  7 —see  FIG. 3 . Clamping area is made, for instance, by applying: high friction coating, thread, notches, grooves or/and rubber insert. 
       FIG. 1  shows two rigid clamps and one spring one. Three clamps is a minimum number for PCB fixity. Any combination of the rigid clamps and spring clamps is allowable depending on specific PCB design and soldering technology. Nevertheless, when all clumps are rigid then base  1  has to be spring-type as on  FIG. 15 . 
       FIGS. 4 and 5  show the PCB clamping area made as a groove. Angle  15  on  FIG. 4  has to be sharp enough to keep PCB in place and to provide auto-clamping of PCBs having various thickness. PCB pullout (disengagement) force can be adjusted by varying the angle opening  15  as well. The larger angle the lower force. Lower supporting shoulder  23  of the groove  11  can be either flat horizontal or have some angle up and down from to meet specific PCB requirements. 
     PCB also can be unclamped by force  19  (see  FIG. 5 ) which can be applied to incline the spring clamp(s) manually or by machine. 
     PCB holding groove can be filled with soft or/and adhesive material, such as a rubber, elastomer and etc. for stronger PCB clamping force. 
       FIG. 7  shows spring-rod holder  17  made either of spring wire or a spring strip and comprising a shoulder  21  for PCB  4  support. 
     ATTACHING RODS TO BASE. PCB rod-clamp  3  (see  FIG. 6 ) can be attached to the base  1  either permanently, for instance by the screw  14  or welding, or with a friction by the magnetic pad  5 . Rod can be attached to the ferromagnetic base directly if made magnetic as well. 
     SPRING ELEMENTS OF THE HOLDER. PCB can be loaded into the PCB HOLDER only if at least rod or/and base made as a spring(s). Spring rod-clamp has to be flexible in the radial direction and rigid in the axial direction. Rod can be circular, rectangular and flat in section. Base  1 , see  FIG. 15 , also can be fabricated as a spring. Rod assembly may include external springs as, for instance pad  8  as on  FIG. 2  and  FIG. 3 , which in this case considered as a part of the rod assembly. Simultaneously applying the spring-base and the spring-rods in the same holder is acceptable. 
     Example 1 
     Spring rod  18  on  FIG. 6  is flexible and made of rubber or elastomer. Rod  3  is rigid. 
     Example 2 
     Spring rod on  FIG. 4  contains several details. Detail  12  made of nylon and attached to the pad  5  by the screw  14 . Standoff  20  is made of plastic or metal and capable to slide along the screw  14 . Spring  13  made of rubber or steel. Operation of such spring rod is: when force  19  (see  FIG. 5 ) is applied to the cone  6 , then pad  5  and standoff  20  compress the spring  13  developing the PCB holding force directed opposite to the force  19  and holding the PCB (PCB is not shown). 
     Example 3 
     Wire-spring rod  17  on  FIG. 7  shows the wire-spring clamp  17  with the PCB holding shoulder  21  attached to the wire. Flat spring can be used instead of circular wire. 
     Example 4 
     Spring pad on  FIG. 3  shows a rod  3  with attached spring pad  8  made of spring material such as a steel, rubber, magnetic rubber etc. Pad  8  can be attached to the base permanently, for instance by screw, glue, welding etc., or with a sliding, if the pad is made of magnetic rubber. 
     Example 5 
       FIG. 14  and  FIG. 15  show as PCB  4  is clamping by the rigid rod-clamps and the spring-base  1  made of spring steel, plastic or elastomer. Spring base  1  bend develops the clamping force  19 . Pads  5  in this example is shown as sliding magnetic pads attached to ferromagnetic base  1 , but may be permanently attached as well. 
     PCB INSERTION INTO HOLDER. There are two examples described for PCB insertion. 2 rods are shown only for clear picture. 
       FIG. 8 ,  FIG. 9  and  FIG. 10  show angle-to-base PCB-insertion. Rod  2  is rigid and fixed to the base  1  and the rod  3  is a spring-type and capable to slide along the base  1 .  FIG. 8  shows initial PCB position, when lower right end of PCB  4  is inserted into clamp  2 .  FIG. 9  shows when PCB edge is sliding along the cone edge  6  of the spring clamp  3 .  FIG. 10  shows when PCB  4  is latched by clamp  11 . Rod  3  on  FIG. 11  has inclination needed to provide a force hold PCB  4  in groove  11 . 
       FIG. 11 ,  FIG. 12  and  FIG. 13  show parallel-to-base PCB insertion. All shown rods are spring-type, attached to the base  1  by magnetic rubber pads  22  working as a spring pads and attaching the rods  3  to the base  1  by magnetic force. Rod(s)  3  is capable to slide along the base  1 .  FIG. 11  shows initial PCB position.  FIG. 12  shows when PCB sliding along the rod(s)  3  with force  9  and inclines the rod(s)  3 .  FIG. 12  shows when PCB is latched in  11 . 
     At least one of above spring details, rod, pad and base, has to operate as a loaded spring providing the force acting either perpendicular or at the angle to the PCB edge. For example,  FIG. 13  shows the force acting perpendicular to the PCB edge and  FIG. 10  shows the angle-acting force to the PCB edge.