Abstract:
A circuit board pallet with an improved securement pin and component positioning arms is disclosed. The improved pin of the present invention is cylindrical pin with an enlarged head. A countersunk hole is drilled in the bottom of the pallet to accommodate the pin. The pin is inserted into the countersunk hole and secured with a high-temperature epoxy resin. The epoxy holds the pin securely in place and keeps the pin from moving up or down. 
     The present invention also comprises at least one arm affixed at one end to a swivel joint. The swivel joint allows the arm to rotate about a vertical axis. The upper portion of the swivel joint is hinged such that the arm can rotate about a horizontal axis. The combination of movement about the horizontal and vertical axis allows the arm to be positioned at any point over the pallet.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is related to the subject matter of U.S. patent application Ser. No. 10/382,700, incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to the field of improvements in pallets for securing electronic circuit boards during the manufacturing process. 
     BACKGROUND OF THE INVENTION 
     Circuit board manufacturing is well known in the art. Electrical components (i.e. processors, memory, capacitors, diodes, resistors, and the like) are generally added to a blank circuit board to create a board which is later installed in an electrical device such as a computer. The blank circuit board must be held in place during the manufacturing process. This is usually accomplished through the use of a circuit board pallet. 
     There are many different patents directed towards methods of securing the circuit board to the pallet. The most common method is to use a plurality of pins extending upwardly from the pallet which fit into holes on the circuit board. The pallet typically has adjustment arms that create either a tensile or compressive force between these pins to hold the circuit board in place. The most common method of attaching the pins to the pallet is to drill a hole either partially through the pallet from the top or completely through the pallet and wedge a portion of the pin into the hole. These two pin attachment methods are illustrated in FIG. 1A and 1B. This configuration leaves a portion of the pin methods are illustrated in FIG. 1A and 1B. This configuration leaves a portion of the pin protruding from the top surface of the pallet so that the circuit board can be attached to the pallet. If the pin is too high, it will interfere with the various component positioning and soldering devices which pass over the circuit board during the manufacturing process. If the pin is too low, it will not sufficiently hold the circuit board in place. Therefore, the distance the pin protrudes from the pallet is an important consideration in the manufacturing process and as a result, the tolerances for pin height are very tight. Furthermore, this pin height must remain within these tight tolerances throughout thousands of cycles of heating and cooling. If the pin height falls out of the tolerance range, then the pallet must be discarded and replaced with a new pallet. 
     Once the circuit board has been affixed to the pallet, the components may be added to the circuit board, typically by soldering. In order for the components to be soldered in place, they must be properly positioned over the circuit board using a component support structure. The components must be held in place sufficiently long for the solder process to be completed and for the solder to cool and harden. Once the solder has cooled and hardened, it securely affixes the component to the circuit board and the component support structure may be removed from the components. 
     The frequent and repetitious soldering and other manufacturing processes subject the pallet to intense heat, often in excess of 550° F. Because the pallet is made from a non-conductive material (i.e. fiberglass) and the pins are metal, the pallet and the pin expand and contract at different rates. The differing rates of contraction and expansion eventually cause the pin to move out of the tolerance range. Therefore, a need exists for a method of installing a pin into a pallet such that it will not fall out of tolerance range after repeated heating and cooling. 
     Moreover, although there have been a myriad of different devices proposed to position the components in place, the previous solutions to this problem have been bulky, complicated, and/or cumbersome to operate. Virtually all of the previous solutions are specific to a certain type of component and/or a certain configuration of components on the board. The prior art does not contain a device that is adaptable to a plurality of different component types and configurations on the circuit board. Consequently, a need also exists for an apparatus and method for efficiently positioning components over a circuit board during the soldering process that is adaptable to a variety of different components. Furthermore, a need exists for a component positioning apparatus that is robust enough to be adaptable to a plurality of different component sizes, shapes, and configurations on the circuit board. 
     SUMMARY OF THE INVENTION 
     The present invention, which meets the needs stated above, is a circuit board pallet with an improved circuit board retention pin and component positioning arms. The improved pin of the present invention is cylindrical in shape with an enlarged head. A countersunk hole is drilled in the bottom of the pallet to accommodate the pin. The pin is inserted into the countersunk hole and secured with a high-temperature epoxy resin. The epoxy holds the pin securely in place and keeps the pin from moving up or down. 
     The present invention also comprises at least one arm. The arm is affixed at one end to a swivel joint. The swivel joint allows the arm to rotate about a vertical axis. The upper portion of the swivel joint is hinged such that the arm can rotate about a horizontal axis. The combination of movement about the horizontal and vertical axis allows the arm to be positioned at any point over the pallet, and consequently, the circuit board. 
     In the manufacturing process, the blank circuit board is secured to the pallet using the securement pins. Next, the arm is positioned away from the circuit board and the components are secured to the arm. The arm is then positioned over the circuit board and secured to the anchor. Finally, the components may be soldered to the circuit board. Additional components may be secured to the arm and installed on the circuit board as needed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1A and 1B are cross-sectional elevation views of prior art circuit board retention pins; 
     FIG. 2A is a perspective view of the present invention with the arm in the lowered position; 
     FIG. 2B is a perspective view of the present invention with the arm in the raised position; 
     FIG. 3A and 3B are cross-sectional elevation views of the pin of the present invention; 
     FIG. 4 is a cross-sectional elevation view of the rail and swivel joint of the present invention taken along line  4 — 4  in FIG. 2B; 
     FIG. 5 is a cross-sectional elevation view of the anchor assembly of the present invention taken along line  5 — 5  in FIG. 2A; 
     FIG. 6 is a plan view of the anchor assembly of the present invention; and 
     FIG. 7 is a perspective view of a circuit board and the present invention with components attached to the arm. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 2A is a perspective view of pallet  100 . The bottom of pallet  100  consists of a flat, rectangular base  102 . A circuit board depression  120  in base  102  is sized to accept the circuit board (not shown). Base  102  contains a plurality of pins  112 , which are used to secure a circuit board to base  102 . Two of the pins  112  in FIG. 2A are attached to adjustable arms  114 . The circuit board has holes that accommodate pins  112 . The circuit board holes are slightly closer together than the pins  112  in base  102 . Thus, when the circuit board is placed in the circuit board depression  120 , an operator (not shown) moves adjustment arms  114  inward so that pins  112  will mate up with the holes in the circuit board. The operator can move adjustment arms  114  by pushing tabs  118 , which are easily accessed through tab access depression  116 . Adjustment arms  114  are spring loaded such that they will create a tensile force on the circuit board when released. After the circuit board has been installed, the operator releases tabs  118  and the tensile force between pins  112  will hold the circuit board in place. Aperture  122  is cut out of base  102  so that the soldering equipment (not shown) can access the bottom of the circuit board. 
     Four rails  104  are attached to the perimeter of base  102 . Rails  104  are “T” shaped when viewed in cross-section. Rails  104  are secured to base  102  with screws inserted up through the bottom of base  102  into rails  104 . Swivel joint  108  slides along one of rails  104  and is rotatably attached to arm  100 . Swivel joint  108  is located at the proximate end of arm  110 . If desired, a plurality of swivel joints  108  and arms  110  can be employed on pallet  100 . The distal end of arm  110  extends across pallet  100  to another rail  104 . Arm  110  is secured to rail  104  by anchor  106 . Anchor  106  slides along rail  104  similarly to swivel joint  108 . If desired, swivel joint  108  and/or anchor  106  may be secured to base  102  using a screw so that they remain in a fixed position with respect to rail  104 . Additionally, a plurality of anchors  106  may be utilized for any of the swivel joint  108  and arm  110  combinations. 
     FIG. 2B is a perspective view of the present invention with arm  110  detached from anchor  106  and positioned away from base  102 . Swivel joint  108  allows arm  110  to be positioned away from base  102  with rotational freedom both parallel and perpendicular to base  102 . In other words, arm  110  has at least a hemisphere of movement. Positioning arm  110  away from base  102  allows an operator (not shown) to attach circuit board components (not shown) to arm  110 . 
     FIG. 3A is a cross-sectional elevation view of pin  112  and base  102 . A high temperature epoxy is used to secure pin  112  inside base  102 . The use of a high temperature epoxy to secure pin  112  inside base  102  is much more reliable than the wedging method used in the prior art. Moreover, when pallet  100  is repeatedly heated and cooled in the manufacturing process, the high temperature epoxy will keep pin  112  affixed in place and ensures that pin  112  does not fall outside the narrow tolerance range. 
     FIG. 3B is an alternative embodiment of pin  112  and base  102 . Although FIG. 3A and 3B illustrate two geometrical embodiments of the present invention, they are not meant to be limiting in any way. Persons skilled in the art will be aware of a myriad of different geometrical configurations of pin  112  and base  102 . For example, the shank of pin  112  that is unexposed may be threaded to engage opposing threads in base  102 . In other words, pin  112  could partially screw into base  102  in addition to being held in place with the high temperature epoxy. Furthermore, if a more secure connection between pin  112  and base  102  is desired, the bottom of pin  112  can be recessed with respect to the bottom surface of base  102 . In this configuration, the high temperature epoxy can be added over the bottom surface of pin  112  creating an even more secure connection between pin  112  and base  102 . 
     FIG. 4 is a detailed illustration of the connection between swivel joint  108 , rail  104 , and base  102 . Rail  104  is affixed to base  102  by a plurality of screws  130 . Screws  130  are inserted from underneath base  102  and are threaded into rail  104 . Threaded screws  130  are not the only method for affixing rail  104  to base  102  and other methods of attachment are known by persons skilled in the art. 
     Swivel joint  108  comprises upper member  109  and lower member  107 . Lower member  107  comprises two sections: one that is “C” shaped to accommodate “T” shaped rail  104 , and another that is “L” shaped, the lower part of which is flush with base  102 . The “C” shaped portion of lower member  107  freely slides laterally along rail  104 . The “L” shaped portion of lower member  107  has a hole to accommodate a screw  130  which may be screwed into base  102 . Screw  130  inserted through lower member  107  into base  102  secures lower member  107  in place and prevents swivel joint  108  from traveling laterally along rail  104 . 
     Swivel joint pin  128  connects lower member  107  to upper member  109 . Washer  124  is disposed between lower member  107  and upper member  109  to reduce the friction associated with rotation of upper member  109  with respect to lower member  107 . Alternatively, washer  124  could be a bearing or any other friction reducing item as determined by persons skilled in the art. 
     Upper member  109  is “C” shaped in cross-section. Upper member  109  freely rotates about swivel joint pin  128  and has 360° of movement in a plane parallel to base  102 . Arm pin  126  runs through arm  110  and the two prongs of upper member  109 . In FIG. 4, arm  110  is positioned away from the viewer (going into the page), parallel to rail  104 . Arm  110  freely rotates about arm pin  126  and has at least 180° of movement in a plane perpendicular to base  102 . In other words, arm  110  in FIG. 4 is hinged about arm pin  126  such that arm  110  can be repositioned to come out of the page instead of going into the page. 
     Swivel joint  108  is novel in that it allows arm  110  to be positioned away from pallet  100  to receive components, and then positioned over pallet  100  to attach the components to the circuit board. When a plurality of arms  110  are utilized, some of arms  110  can be positioned away from the circuit board so that they may receive the components. Simultaneously, other arms  110  can be positioned over the circuit board so that the components can be soldered to the circuit board. 
     FIG. 5 is a detailed illustration of the connection between anchor  106  and arm  110 . Connector  138  is disposed at the distal end of arm  110  in relation to swivel joint  108 . Connector  138  comprises a cylindrical center shaft and a shorter cylindrical member perpendicularly attached to each end of the center shaft of connector  138 . Connector  138  freely rotates 360° within arm  110 . Spring  140  is disposed between arm  110  and connector  138  such that the spring force is always attempting to bring the lower portion of connector  138  in contact with the lower face of arm  110 . 
     Similarly to lower member  107  in FIG. 4, anchor  106  has a “C” shaped portion and an “L” shaped portion. The “L” shaped portion of anchor  106  can be secured to base  102  with screw  130 , similar to lower member  107 . The “C” shaped portion of anchor  106  slides along rail  104  similar to lower member  107 . However, the inside surface of the “C” shaped portion of anchor  106  does not contact the upper surface of rail  104 . Instead, an anchor aperture  139  is created. Anchor aperture  139  is defined as the cavity between anchor  106  and rail  104 . As seen in FIG. 6, anchor aperture  139  has an elongated opening on the upper portion of anchor  106 . When arm  110  is positioned over anchor  106 , connector  138  can be vertically displaced downward and the lower portion of connector  138  will pass through the elongated slot of anchor aperture  139 . If connector  138  is then rotated 90° and released, spring  140  will cause the lower portion of connector  138  to come into contact with the inside face of anchor  106  and the lower face of arm  110  will come into contact with the upper face of anchor  106 . In this manner, arm  110  can be secured to anchor  106 . 
     FIG. 7 is an illustration of circuit board  132  installed in pallet  100 . Components  134  have been attached to arm  110  via component holders  136 . Arm  110  holds components  134  in place over circuit board  132  while a soldering machine (not shown) solders component  134  into place on circuit board  132 . In alternative embodiments, arm  110  is connected to anchor  106  at both the proximate and the distal end. This embodiment yields an arm  110  that is fully detachable from the pallet  100 . In further alternative embodiments, a plurality of arm  110  and swivel joint  108  combinations are used to attach components  134  to circuit board  132 . 
     With respect to the above description, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. The novel spirit of the present invention is still embodied by reordering or deleting some of the steps contained in this disclosure. The spirit of the invention is not meant to be limited in any way except by proper construction of the following claims.