SYSTEMS AND METHODS FOR PRINTED CIRCUIT BOARD SUPPORT

TECHNICAL FIELD OF THE INVENTION

An adjustable support and conveyance mechanism is configured for use with comparatively large and/or wide printed circuit boards.

BACKGROUND OF THE INVENTION Today, printed circuit boards (PCBs) are used in most electronics devices. PCBs include many electrical or electronic components such as integrated circuit chips, resistors, transistors, capacitors, etcetera. As part of their manufacturing process, PCBs are heated while being conveyed through a furnace or oven generally known as a reflow oven. As PCBs travel through a reflow oven for processing, the PCBs are supported on and conveyed by one or more supporting and conveying chains. Typically, a PCB is supported along each of its lateral ends by a support chain. However, relatively large PCBS, such as PCBs with comparatively wide widths, are subject to the risk of warping and/or sagging as a result of being processed, e.g., heated, while being conveyed through a reflow oven. Depending on the size of a PCB, one or more support chains can therefore be employed to help to support the PCB along locations of the PCB in addition to its lateral edges such as, for instance, along a center point of the PCB in order to provide support to the PCB and to help to reduce the risk of warping and/or sagging. Larger or wider PCBS that may benefit from additional support are typically designed for such support by including along a surface of a PCB one or more "keep-out" zones that are areas along the PCB that lack or are at least generally free of electrical or electronic components in order a support chain may contact the PCB without damage to such components. Many PCB designs however do not include "keep-out" zones and therefore are more difficult to support during processing through a reflow oven. SUMMARY OF THE INVENTION

In an aspect, the invention provides a reflow oven for processing printed circuit boards comprises a housing configured to define within its interior a chamber, the chamber extending along at least a portion of the interior of the reflow oven. The reflow oven further comprises at least one lateral end support chain disposed within the chamber and configured to support a printed circuit board along one of its lateral ends and further configured to help to convey the

printed circuit board along at least a portion of the length of the chamber, and a board support chain disposed within the chamber and configured to support the printed circuit board and further configured to help to convey the printed circuit board along at least the portion of the length of the chamber. The board support chain includes a multiple of board support positions, each board support position being defined by a stopper finger and one or more support fingers. Each of the stopper and support fingers are disposed along each board support position in relation to one another and at locations such that, where the board support chain receives the printed circuit board, the stopper finger is disposed against or is proximate to an edge of the printed circuit board and the one or more support fingers contact the printed circuit board at one or more discrete areas of a surface of the printed circuit board.

Implementations of the invention may include one or more of the following features. Each distance between adjacent board support positions of the multiple of board support positions is substantially the same. One or more distances between adjacent board support positions of the multiple of board support positions are not the same. A location of the stopper finger relative to a position of at least one of the support fingers of a given board support position helps to facilitate alignment of the printed circuit board along the board support position and contact of at least one of the support fingers to a discrete area of the surface of the printed circuit board. The distance between each of the one or more support fingers within a given board support position is substantially the same. The distances between each of the one or more support fingers within a given board support position are not the same.

Implementations of the invention may include one or more of the following features. The locations of the one or more support fingers within a given board support position correlate with the locations of the one or more discrete areas of the surface of the printed circuit board. The one or more discrete areas of the printed circuit board surface lack or are at least generally free of electrical or electronic components. The one or more support fingers are removably connected to the board support chain. The one or more support fingers are spring loaded to the board support chain. At least one of the one or more support fingers defines a configuration or shape to facilitate contact with one of the one or more discrete areas of the surface of the printed circuit board. The board support chain is disposed within the chamber along a central axis of the chamber. The board support chain is disposed within the chamber at a position offset from a central axis of the chamber.

Implementations of the invention may further include one or more of the following features. The reflow oven is further configured to determine by a timing calculation the position of a given board support position along the board support chain. The timing calculation employs at least a speed at which the board support chain travels through the chamber. The timing calculation employs a location of the stopper finger of a given board support position in the chamber. The location of the stopper finger is detected via a sensor. The reflow oven further includes a buffer conveyor operatively associated with the reflow oven and disposed to singulate individual printed circuit boards to the board support chain and the at least one lateral end support chain. The reflow oven is further configured to produce one or more signals to indicate to the buffer conveyor when the buffer conveyor is to singulate a printed circuit board to the board support chain and the at least one lateral end support chain. The reflow oven produces the one or more signals in response to the detection of the position of the stopper finger of a given board support position within the chamber. The board support chain is at least partially conveyed through the chamber at an ascending incline to enable each of the one or more support fingers of a given board support position to sequentially engage with the one or more discrete areas of the printed circuit board surface. The board support chain is at least partially conveyed through the chamber at a descending incline to enable each of the one or more support fingers of a given board support position to sequentially disengage from the one or more discrete areas of the printed circuit board. The board support chain is disposed within the chamber such that the board support chain supports a substantially central area of the printed circuit board.

In another aspect, the invention provides a conveyance system for conveying articles of manufacture through a processing system, the conveyance system comprises at least one support conveyor disposed with the processing system and configured to support one or more articles and further configured to help to convey the one or more articles by at least a portion of the processing system, and a multiple of support positions defined along the at least one support conveyor. Each support position is defined by a stopper finger and one or more support fingers. Each of the stopper and support fingers is disposed along each support position in relation to one another and at locations such that, where the support conveyor receives an article, the stopper finger is disposed against or proximate to a leading portion of the article and the one or more support fingers contact the article at one or more discrete locations. A location of the stopper finger relative to a position of at least one of the support fingers of a given support position helps

to facilitate alignment of the article along the given support position and contact of at least one of the supports fingers to at least one of the discrete locations of the article.

Implementations of the invention may include one or more of the following features. The locations of the one or more support fingers within a given support position correlate with the positions of the one or more discrete locations of the article. The one or more support fingers are removably connected to the support conveyor. At least one of the one or more support fingers defines a configuration or shape to facilitate contact with one of the one or more discrete locations of the article. The conveyance system is further configured to determine by a timing calculation the position of a given support position along the support conveyor. The timing calculation employs at least a speed at which the support conveyor travels. The timing calculation employs a location of the stopper finger of a given support position by the processing system. The location of the stopper finger is detected via a sensor. The conveyance system is further configured to produce a signal to indicate to an article supply means, which is associated with the processing system, to singulate an article to the support conveyor. The conveyance system produces the signal in response to the detection of the position of a stopper finger of a given support position relative to the processing system.

Implementations of the invention may further include one or more of the following features. The support conveyor is at least partially conveyed by the processing system at an ascending incline to enable each of the one or more support fingers of a given support position to sequentially engage the one or more discrete locations of the article. The support conveyor is at least partially conveyed by the processing system at a descending incline to enable each of the one or more support fingers of a given support position to sequentially disengage from the one or more discrete locations of the article.

In a further aspect, the invention provides a method of conveying a printed circuit board through a processing system, and the method comprises providing a board support chain, the board support chain including a multiple of board support positions, each board support position being defined by a stopper finger and one or more support fingers; adjusting at least one of the support fingers to correspond with a design or a layout of one or more components along a surface of the printed circuit board; delivering the printed circuit board to the board support chain; receiving the printed circuit board along a given board support position such that the stopper finger is disposed against or proximate to an edge of the printed circuit board and the one

or more support fingers contact the printed circuit board at one or more discrete areas of a surface of the printed circuit board, and conveying the printed circuit board through the processing system.

Implementation of the invention includes one or more of the following. The method further comprises conveying the board support chain at least partially through the processing system at an ascending incline to enable each of the one or more support fingers of a given board support position to sequentially engage with the one or more discrete areas of the printed circuit board surface. The method further comprises conveying the board support chain at least partially through the processing system at a descending incline to enable each of the one or more support fingers of a given board support position to sequentially disengage from the one or more discrete areas of the printed circuit board surface. The method further comprises determining a location of the stopper finger relative to a position of at least one of the support fingers of a given board support position to help to facilitate alignment of the printed circuit board along the given board support position and contact of at least one of the support fingers to at least one of the discrete areas of the printed circuit board surface. The method also comprises determining a location of a given board support position along the board support chain by a timing calculation. The timing calculation employs at least a speed at which the board support chain travels. The timing calculation employs a location of the stopper finger of a given board support position in the processing system. The method further comprises providing one or more signals to indicate when a printed circuit board delivery means is to singulate a printed circuit board to the board support chain. Provide the one or more signals includes producing the one or more signals in response to the detection of the position of the stopper finger of a given board support position in the processing system.

Various aspects of the invention may provide one or more of the following capabilities and advantages. A printed circuit board (PCB) can be supported and conveyed through processing equipment using a support and conveyance belt or chain that is configured to match a PCB design, or, in other words, the general configuration and layout of electrical/electronic components along one or more surfaces of the PCB. Reliance on "keep-out" zones on PCBs to facilitate support and conveyance of PCBs through processing equipment can be reduced in comparison to prior techniques. Reducing "keep-out" zones along surfaces of PCBS to accommodate PCB support mechanisms can help to increase surface areas of PCBs available for

receiving and mounting electrical and electronic components. Taller and/or larger electrical/electronic components can be mounted to one or more surfaces of a PCB in comparison to prior techniques. Warping and/or sagging of a PCB due to processing conditions, e.g. heating, can be minimized or reduced in comparison to prior techniques. A PCB can be supported in multiple discrete locations along one or more its surfaces. More than one PCB design, or layout of electrical or electronic components along one or more surfaces of a PCB, can be accommodated with a single PCB support mechanism to thereby enable processing of multiple PCB designs simultaneously or during one processing run. Singulation of PCBs from a supply conveyor can be accomplished, for instance, to help to provide individual PCBs at particular locations along a support and conveyance belt or chain of processing equipment.

These and other capabilities of the invention, along with the invention itself, will be more fully understood after a review of the following figures and detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. l is a diagram of a reflow oven including support and conveyance belts or chains according to the invention;

FIG. 2 is a diagram of a printed circuit board and a possible position of a board support belt or chain relative to the printed circuit board according the invention;

FIGS. 3 A and 3B are diagrams of a board support position along a board support belt or chain including a stopper finger and support fingers according to the invention; FIG. 4 is a diagram of a link of a stopper finger;

FIG. 5 A is a diagram of an adjustable link and a removable portion of a support finger; FIG. 5B is a diagram of an adjustable link and a removable portion of the support finger shown in FIG. 5A;

FIG. 5C is a plan view of a portion of a board support belt or chain including an adjustable link;

FIG. 6 is a diagram of a removable portion of a stopper finger; FIG. 7 is diagram of removable support fingers and a board support belt or chain;

FIG. 8 is a plan view of a reflow oven such as that shown in FIG. 1 ;

FIG. 9 is a diagram of a board support belt or chain and a sprocket;

FIGS. 10A- 1OM include illustrations depicting a progression of a printed circuit board engaging with a board support position along a board support belt or chain;

FIGS. 1 IA-I IK include illustrations depicting a progression of the printed circuit board of FIGS. 10A- 1OM disengaging with the board support position along the board support belt or chain; and

FIG. 12 is a block flow diagram of a method of processing a printed circuit board through a refiow oven such as that shown in FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention provides systems and techniques for providing processing equipment, such as, for example, a refiow oven with an adjustable board support mechanism for use in supporting and conveying printed circuit boards (PCBs). Specifically, processing equipment or a refiow oven includes a board support mechanism configured with at least one support belt or chain to support and to convey PCBs into and within the processing equipment or refiow oven. The board support belt or chain is configured to support and to convey PCBs and has a series of board support positions. Each of the series of support positions includes multiple adjustable and/or removable board support fingers including at least one stopper finger and a number of support fingers. The support fingers are configured to contact one or more discrete areas along one or more surfaces of each PCB to support the PCB along the support belt or chain. In addition, the support fingers are removably disposed at locations along the board support belt or chain. The removable support fingers may conform board support positions to at least generally correlate to the positions and/or the layout of electrical or electronic components along one or more surfaces of PCBs to help to reduce the reliance upon "keep-out" zones along PCB surfaces for placement of PCBs on a support belt or chain. The processing equipment or refiow oven employs the stopper finger to help to control a speed at which PCBs are delivered to the processing equipment or refiow oven and to help to provide a reference point that the processing equipment or refiow oven uses to help to align a supported PCB on one or more support fingers, such as the support fingers of a given board support position. The support fingers are constructed and arranged as adjustable and/or removable fingers that can be removed and repositioned along the board support chain, e.g., upstream from the stopper finger, to help to

accommodate the specific positions of "keep-out" zones of a certain PCB design and configuration. Alternatively, or additionally, the processing equipment or reflow oven can be operatively coupled with a local or remote processor that, along with the stopper finger, helps to control a speed at which PCBs are delivered to and conveyed within the processing equipment or reflow oven and to help to facilitate alignment of a supported PCB on the support fingers. The board support mechanism may be configured with a board support belt or a board support chain, depending upon the processing conditions, the configuration of the PCBs and any other factors that may affect the processing, placement and conveyance of PCBS through processing equipment or a reflow oven. Other embodiments are within the scope of the invention.

For purposes of disclosing the invention, the systems and methods of providing PCB support are described below with reference to at least one board support chain. However, the invention is not limited in this respect and envisions that other configurations of the board support mechanism according to the invention are possible and may include, but are not limited to, at least one board support belt, conveyor, transport and other mechanical apparatus for supporting and for moving articles, including PCBs.

Referring to FIG. 1, in an aspect, the invention provides a reflow oven 5 including a housing 11, end support chains 10 and 15, at least one board support chain 20, and a chamber 25 extending along at least a portion of the length of the housing 11. The end support chains 10 and 15 and the board support chain 20 typically extend through at least a portion of the length of the chamber 25 of the reflow oven 5 to convey PCBS from one end of the reflow oven 5 and the chamber 25, e.g., an entrance point into the chamber 25, to a second opposite end of the reflow oven 5 and the chamber 25, e.g., an exit point from the chamber 25. Preferably, the support chains 10, 15, and 20 are configured to operate at substantially the same speed, although other configurations of the board support mechanism according to the invention are possible.

Alternatively, or additionally, the reflow oven 5 is operatively coupled with a local or remote processor 12 that is configured to facilitate the operation of the reflow oven 5, e.g., to control a speed at which one or more of the chains 10, 15, and 20 moves through the reflow oven 5. The reflow oven 5 is configured to facilitate reflow soldering of components 35 to a PCB 40, although it can be used for other purposes. The reflow oven 5 can include at least one heating

zone to heat PCBs 40 conveyed therethrough to help to achieve, for instance, reflow soldering of electrical or electronic components to one or more surfaces of the PCBs.

The end support chains 10 and 15 and the board support chain 20 are each configured to convey a PCB 40 through the reflow oven 5, e.g., through at least a portion of the chamber 25, for processing of the PCB 40. The end support chains 10 and 15 are configured to support a PCB 40 along an area that is proximate or substantially adjacent or aligned with each lateral end 4OA and 40B of the PCB 40, as shown in FIG. 1. In one configuration, the board support chain 20 is disposed within the chamber 25 and is configured to support a PCB 40 along the PCB 's approximate center 41, as shown in FIG. 1, although the board support chain 20 may be disposed and configured to support a PCB 40 along any area of the PCB 40 between its lateral ends 4OA and 4OB. The invention is not so limited and envisions that other arrangements, configurations, and positions of the at least one board support chain 20 are possible within the reflow oven 5, including, but not limited to, a board support chain 20 disposed within the chamber 25 and configured at an off-center position relative to a central axis of the chamber 25 within the reflow oven 5 or an off-center position relative to an area defined between the end support chains 10 and 15, and/or one or more board support chains 20 disposed within the chamber 25. The board support chain 20 is configured with one or more adjustable and/or removable support fingers 30. The adjustable fingers 30 are configured to contact a PCB 40, e.g., to support the PCB 40, at one or more areas along one or more surfaces of the PCB 40, e.g., that lack or are at least generally free of the components 35, such as shown in FIG. 1.

Referring to FIG. 2, and with further reference to FIG. 1, the PCB 40 includes a plurality of electrical or electronic components 35 and at least one surface 50 configured to receive and to mount the components 35, e.g., by soldering the components 35 to (or through) the surface 50. The components 35 are arranged on the surface 50 to define, for instance, "keep-out" zones 55 and 60 that lack or are at least generally free of components 35. The "keep-out" zones 55 and 60 may be configured to receive the lateral end chains 10 and 15.

The board support chain 20 may be disposed within the chamber 25 and configured to receive and to support a PCB 40 along an area 65 of the PCB 40 that substantially overlaps with the board support chain 20, e.g., an area 70. In one configuration of the invention, the board support chain 20 is centrally disposed within the chamber 25, e.g., in substantial alignment with a central axis of the chamber 25 or at a position substantially equidistant from the end support

chains 10 and 15. The area 70 of the board support chain 20 may thereby be disposed in relation to a PCB 40 to enable the PCB area 65 to overlap the board area 70 to facilitate support of the PCB 40 along a substantially central or mid-portion of the PCB 40. In another configuration of the invention, the board support chain 20 is disposed within the chamber 25 at an offset position or orientation, e.g., relative to the central axis of the chamber 25 or relative to the end support chains 10 and 15. In this manner, the position of the board support chain 20 helps to accommodate various PCB designs and further helps to reduce reliance upon "keep-out" zones along surfaces of PCBs. Preferably, the board support chain 20 does not support a PCB 40 at one or more locations along the surface 50 of the PCB 40 at which electrical or electronic component(s) 35 is/are positioned.

Referring to FIG. 3 A and 3B, and with further reference to FIGS. 1 and 2, the board support chain 20 includes a multiple of board support positions 100. In addition, the board support chain 20 is disposed and is configured to be used along with a sprocket 75, as described below with reference to FIG. 9. The sprocket 75 is disposed and is configured to help to convey the board support chain 20 through the chamber 25. Each board support position 100 preferably includes at least one stopper finger 110 and at least one support finger 105. The support fingers 105 are disposed along the board support chain 20 and are configured to support a PCB 40 and to removably connect to the board support chain 20, e.g., via a fastener or fastening device. The stopper finger 110 is configured and is disposed along the board support chain 20 to extend upwardly and beyond an edge of the PCB 40, e.g., as shown in FIG. 3A. The stopper finger 110 is configured and is disposed along the board support chain 20 such that, when a PCB 40 is conveyed to and/or placed on the chain 20, the stopper finger 100 is positioned against or is proximate to a leading edge of the PCB 40 and the support fingers 105 of the board support position 100 are substantially aligned with a support pattern, e.g., comprised of one or more "keep-out" zones, along the surface 50 of the PCB 40, wherein the support pattern includes a configuration, an arrangement and/or a layout of one or more electrical and/or electronic components 35. Each of the support fingers 105 may thereby contact a discrete area of the support pattern, e.g., lacking or at least generally free of components 35, to provide support to a PCB 40 at desired or required areas along its surface 50. In this manner, each board support position 100 along the board support chain 20 may be configured with an arrangement and/or a layout of the stopper finger 110 and the one or more support fingers 105 that substantially

corresponds to and/or accommodates a specific support pattern, or configuration, arrangement and/or layout of components 35, along one or more surfaces 50 of a PCB 40.

While the configuration or layout that the support fingers 105 help to define along the board support chain 20 includes each finger 105 disposed at a similar position relative to another finger 105, e.g., substantially the same area exists between each finger 105, as shown in FIG. 3A, the positions of the support fingers 105 can vary relative to one another within the board support position 100. The configuration or layout of the support fingers 105 from one board support position 100 to another is preferably and typically the same. In addition, the pitch of the chain 20, e.g., the minimum spacing between a pair of adjacent support fingers 105, is preferably three- eighths of an inch (3/8"), although the invention is not limited in this respect and other pitch sizes are possible and envisioned, as well as one or more different board support positions 100 with different spacing between adjacent support fingers 105.

While the support fingers 105 are shown in FIGS. 3 A and 3B as being substantially vertically straight, other configurations of the support fingers 105 are possible. For example, one or more support fingers 105 may be bent and/or shaped such that each of the one or more fingers 105 contacts the surface 50 of the PCB 40 at a desired or required location. In addition, the stopper finger 110 is disposed and is configured to help to facilitate alignment of a PCB 40 within a board support position 100.

Referring to FIG. 4, the stopper finger 110 may be configured to define any of a variety of different shapes and/or sizes to help to align the PCB 40 at one or more desired or required locations within the board support position 100. The stopper finger 110 may be configured to be removable, as described below, or may be configured to be permanently secured along the board support chain 20 and/or within the chamber 25. The stopper finger 110, as shown in FIG. 4, typically includes a link 325 with a stopper portion 330. The support fingers 105 are disposed along the board support chain 20 such that where a

PCB 40 is being processed through the reflow oven 5, each support finger 105 contacts and/or supports the PCB 40 in one or more desired or required locations, or discrete areas, along the PCB surface 50 that lack or are at least generally unoccupied or free of one or more components 35. For instance, with reference to FIG. 2, the support fingers 105 may be configured to contact a PCB 40 along the area 65 that include one or more discrete areas preferable for contact with the support fingers 105. The configuration and layout of the support fingers 105 within a board

support position 100 may vary depending on the design of a PCB 40 and/or the layout or arrangement, or support pattern, of one or more of the components 35 on the PCB surface 50. For instance, locations of the components 35 may vary from one PCB design to another, such that, the desired or required positions or discrete locations for contact by the supports fingers 105 may vary from one PCB 40 to another.

Referring to FIGS. 5A-5C, 6, and 7, the support fingers 105 and the stopper finger 110 may be implemented using any of a variety of configurations and arrangements; and the invention is not limited in this respect and anticipates that other configurations and arrangements other than those described herein are possible and envisioned. As shown in FIGS. 5A-5C, the support finger 105 may include a link 250 and a finger portion 280. The link 250 of a support finger 105 includes one or more protrusions 255 and 260 and defines one or more apertures 265, 270, and 275. The finger portion 280 of a support finger 105 defines apertures 285 and 290. The one or more protrusions 255 and 260 are each configured such that one of the apertures 285 and 290, respectively, receives at least a portion of the protrusion 255 and 260 in order to hold the finger portion 280 in place, e.g., by frictional forces. For instance, the finger portion 280 is configured to be installed on the link 250 by moving the finger portion 280 in the direction of the arrow 292 shown in FIG. 5 A, such that the apertures 285 and 290 receive and engage with at least a portion of the protrusions 255 and 260, respectively. Alternatively, the link 250 may include apertures defined at the positions of the protrusions 255 and 260 with each aperture configured to receive at least a portion of a fastener, e.g., screw, which can be used to attach the finger portion 280 to the link 250.

Referring to FIGS. 5C and 6, the stopper finger 110 includes a stopper portion 295 that may be configured to couple to the link 250 in a manner similar to that described above with respect to the finger portion 280 of the support finger 105. The apertures 265 and 270 may be configured to receive at least a portion of a pin 300 that is configured to couple with multiple links 250.

Referring to FIG. 7, a chain 350, e.g., which may be a portion of the board support chain 20, includes multiple links 355 and protrusions 360. The chain 350 is configured to receive finger portions 365. Each finger portion 365 includes shoulder portions 370 and 371, detents 375 and 386, and ends 380 and 381. Each detent 375 and 386 is configured to receive at least a portion or part of one of the protrusions 360. Each shoulder portion 370 and 371 is configured to

inhibit (and possibly prevent) the finger portion 365 from slipping downward when the finger portion is installed on the chain 350. The finger portions 365 are configured to spring load to the chain 350 such that when the ends 380 and 381 are squeezed in a direction of arrows 385 shown in FIG. 7, the finger portion 365 is biased in the direction of arrow 390. A spacing 395 between a pair of adjacent protrusions 360 is configured such that when a finger portion 365 is installed between the pair of adjacent protrusions 360, the bias of the finger portion 365 couples the finger portion 365 to the protrusions 360. Likewise, the stopper finger 110 may include a stopper portion 205 that is configured similar to that described above with respect to the finger portion 365. Referring to FIG. 8, and with further reference to FIG. 3 A, the reflow oven 5 is configured to receive a PCB 40 from a buffer conveyor 150, e.g., operatively coupled with the reflow oven 5. The reflow oven 5 is configured to provide a control signal to the buffer conveyor 150 that indicates when another PCB 40 may be delivered or conveyed from the buffer conveyor 150 to the reflow oven 5 and to one of the multiple of board support positions 100. The reflow oven 5 is configured to use a timing calculation and/or a sensor to help to determine the location of each board support position 100 along the board support chain 20 and within the chamber 25. For instance, the reflow oven 5 is configured to track a speed of the board support chain 20 to help to determine the positions of the board support positions 100. Furthermore, the reflow oven 5 is also configured to use a sensor 155 to help to track the position of the board support chain 20 or a specific board support position 100. For instance, the sensor 155 may be a retro-reflective sensor that includes a corresponding reflector 160, and is configured to determine the location of the stopper finger 110 of a given board support position 100 by detecting a loss of reflection from the reflector 160. The invention is not limited in this respect and envisions other types of sensors may be employed. The reflow oven 5, with or without control provided by the local or remote processor 12, is configured to cause the buffer conveyor 150 to deliver PCBs 40 to the chamber 25 in a controlled manner using the control signal(s) provided by the reflow oven 5. For instance, the buffer conveyor 150 is configured to start and stop in response to receiving the control signal(s) from the reflow oven 5 thereby providing, preferably, one of multiple PCBs 40 disposed on the buffer conveyor 150 to the chamber 25 when the reflow oven requests delivery of the PCB 40. The buffer conveyor 150 is configured to operate at the same or different speed as the support

chains 10, 15, and 20. Preferably, PCBs 40 are loaded on the buffer conveyor 150 such that adjacent ones of the PCB 40 are touching. Further, the reflow oven 5 is configured to cause the buffer conveyor 150 to singulate PCBs 40, e.g., provide PCBs 40 to the chamber 25 or the reflow oven 5 whereby adjacent ones of the PCBs 40 are spaced from one another by a predetermined amount or distance, such that, such interval corresponds to the interval between adjacent ones of the board support positions 100. The reflow oven 5 is configured to cause the buffer conveyor 150 to load PCBs 40 onto the support chains 10, 15, and 20, such that, the leading edge of a PCB 40 contacts or is proximate to the stopper finger 110, e.g., which can be used to align the PCB 40 with respect to the positions of the support fingers 105 within the board support position 100 that the stopper finger 110 helps to define.

Depending on the design or the configuration and layout of components 35 along surfaces of PCBs 40, the support fingers 105 of the board support chain 20 may collide with one or more components 35, e.g., if one or more components 35 are too tall and/or large, as the support finger 105 rotates about the sprocket 75 that is employed to convey the board support chain 20 through the chamber 25. For instance, referring to FIG. 9, as a support finger 105 rotates around the sprocket 75, it may collide with one or more components 35. As described below with reference to FIGS. 10A- 1OM, a gradual incline and/or decline may be used to preferably avoid collisions between the support fingers 105 of the board support chain 20 and one or more components 35 along one or more surfaces 50 of a PCB 40. Referring to FIGS. 10A- 1OM, the illustrations depict the progression of a support finger

105 and its link 21 of a board support position 100 along the board support chain 20 as it engages with a PCB 40 as the board support chain 20 travels through the chamber 25. The support finger 105 and its link 21 travel through the chamber 25 and engage a PCB 40 as a result of a gradual incline 200 at which the board support chain 20 travels or is conveyed through the chamber 25 of the reflow oven 5. The sprocket 75 is positioned such that the support fingers 105 do not collide with one or more of the components 35 as the support fingers 105 rotate around the sprocket 75. Preferably, the angle Ii of the gradual incline 200 of the board support chain 20 is within a range of about 2 degrees to about 10 degrees, and is preferably about 3.66 degrees. The invention however is not limited in this respect and envisions other angles I ₁ of the incline 200 are possible, e.g., depending on a design of a PCB 40, a configuration or layout of electrical and/or electronic components 35 on one or more surfaces 50 of a PCB 40, the height of one or more

components 35, a proximity of one or more components 35 to one or more "keep-out" zones along one or more surfaces 50 of a PCB 40, the height of one or more support fingers 105, and/or other factors, including any processing or reflow variables and parameters. The gradual incline 200 is configured such that as the link 21 advances, e.g., in the direction of an arrow 205 shown in FIGS. 1OA and 1OB, and the support finger 105 gradually moves closer to a PCB 40 and eventually contacts the PCB 40, e.g., as shown in FIG. 1OL, and thereby gradually engages with one or more discrete areas along one or more surfaces 50 of the PCB 40.

Referring to FIGS. 1 IA-I IK, the illustrations depict the progression of a support finger 105 and its link 21 of a board support position 100 along the board support chain 20 as it disengages from a PCB 40 as the board support chain 20 travels through the chamber 25. The support finger 105 and its link 21 travel through the chamber 25 and disengage from a PCB 40 as a result of a gradual decline 210. Preferably, the angle I ₂ of the gradual decline 210 is within a range of about 2 degrees to about 10 degrees, and is preferably 3.66 degrees. The invention however is not limited in this respect and envisions other angles I ₂ of the decline 210 are possible, e.g., depending on a design of a PCB 40, a configuration or layout of electrical and/or electronic components 35 on one or more surfaces 50 of a PCB 40, the height of one or more components 35, a proximity of one or more components 35 to one or more "keep-out" zones along one or more surfaces 50 of a PCB 40, the height of one or more support fingers 105, and/or other factors, including any processing or reflow variables and parameters. The gradual decline 210 is configured such that as the link 21 advances, e.g., in the direction of an arrow 215, e.g., as shown in FIG. 1 IA, 215, and the support finger 105 gradually is positioned further away from a PCB 40 and eventually disengages the support finger 105 from the PCB 40, e.g., as shown in FIGS 1 ID-I IK, without coming into further contact with one or more components 35.

Referring to FIG. 12, and with further reference to FIGS. 1-1 IK, in another aspect, the invention provides a method 1200 of processing a PCB 40 through processing equipment or a reflow oven 5 including the stages shown. The method 1200, however, is exemplary only and not limiting. The method 1200 may be altered, e.g., by having stages added, removed, altered, or rearranged.

At stage 1205, one or more of a multiple of support fingers 105 disposed along the board support chain 20 are adjusted to define one or more board support positions 100 and to help to match or accommodate a particular PCB design and/or one or more support patterns, wherein a

support pattern includes one or more arrangements or layouts one or more electrical or electronic components 35 disposed along one or more surfaces 50 of one or more PCBs 40. For instance, the support fingers 105 are positioned along the board support chain 20, and may be shaped, to support each of the PCBs 40 in one or more discrete areas of one or more surfaces 50 that are lacking or are at least generally free of one or more components 35, e.g., the area 65. The stopper finger 110 is positioned, and may be shaped, such that the stopper finger 110 provides a registration or reference point that may be used to help to align a PCB 40 on the board support chain 20, e.g., at a given board support position 100. The stopper finger 110 is also positioned and/or configured such that the reflow oven 5 can track the location of the board support positions 100 along the board support chain 20. Preferably, each of the board support positions 100 is substantially identical to other positions 100, although other configurations of the board support positions 100 are possible, e.g., each of the board support positions 100 can be configured to work with and accommodate a different PCB design, arrangement or layout of one or more components 35 and/or support patterns along one or more surfaces 50 of one or more PCBs 40. The board support chain 20 and the board support positions 100, defined by placement of the support fingers 105 and/or the stopper finger 110, thereby help to enable the reflow oven 5 to process one or more specific PCB designs and/or arrangements or layouts of components 35, e.g., simultaneously or during a single process run.

At stage 1210, PCBs 40 are provided to the reflow oven 5 using the buffer conveyor 150. The buffer conveyor 150 provides a single one of multiple of PCBs 40 to the reflow oven 5, e.g., in accordance with control signal(s) the reflow oven 5 provides to the buffer conveyor 150. The multiple of PCBs 40 are thereby delivered to the reflow oven 5 such that the PCBs 40 are singulated to the board support chains 10, 15 and 20.

The reflow oven 5 tracks the locations of the board support positions 100, e.g., by tracking the speed of the support chains 10, 15, and 20 and/or by using the sensor 155. The sensor 155 tracks the locations of the board support positions 100 by determining the locations of the stopper fingers 110. The sensor 155 transmits signal(s), e.g., infrared signal(s), which is/are reflected by the reflector 160 towards the sensor 155. The sensor 155 determines the location of each stopper finger 110 by sensing an interruption in the reflection from the reflector 160, e.g., when the stopper finger 110 breaks the signal path of the signal(s) transmitted by the sensor 155. The buffer conveyor 150 is configured to provide PCBs 40 to the support chains 10, 15, and 20

such that the leading edge of each PCB 40 is registered against or is proximate to the stopper finger 110, e.g., thereby helping to align the PCB 40 within the board support position 100 which the stopper finger 110 helps to define along the board support chain 20.

At stage 1215, a PCB 40 is supported by the chains 10, 15, and 20. The support chains 10 and 15 support the lateral ends 40A and 4OB of the PCB 40, e.g., along "keep-out" zones 55 and 60, and the board support chain 20 supports the PCB 40, e.g., at about a center position or orientation along the PCB 40 or at a location or position along the PCB 40 that is off-set relative to a center portion or orientation along the PCB 40. Alternatively, the board support chain 20 supports the PCB 40 along a location or position along the chain 20 that is off-set relative to a center portion or orientation of an area defined between the two end support chains 10 and 15. The support fingers 105 support the PCB 40 at one or more discrete areas, e.g., the area 65, along one or more surfaces 50 of the PCB 40 such that the PCB 40 is supported at one or more locations that lack or are at least generally free of one or more components 35. Additionally, the support fingers 105 may be positioned relative to the PCB 40 along the board support chain 20 using the gradual incline 200. As the support fingers 105 travel along with conveyance of the board support chain 20, in the direction of the arrow 205 shown in FIG. 1OA, the support fingers 105 are gradually raised toward the PCB 40 to support the PCB 40. The use of the gradual incline 205 is optional, for instance, depending on the PCB design and/or the arrangement and/or layout of the one or more components 35 along one or more surfaces 50 of the PCB 40, and/or other factors described above with reference to FIGS. 10A- 1OM.

At stage 1220, PCBs 40 are conveyed through at least a portion of the chamber 25 of the reflow oven 5 and are thereby processed in whole or in part. The PCBs 40 are conveyed through the reflow oven 5 by the support chains 10, 15, and 20. The support chains 10, 15, and 20 may operate at substantially the same speed. As the support fingers 105 travel along with conveyance of the board support chain 20, in the direction of the arrow 215 shown in FIG. 1 IA, the support fingers 105 are gradually lowered away from the PCB 40. The use of the gradual decline 210 is optional, for instance, depending on the PCB design and/or the arrangement and/or layout of the one or more components 35 along one or more surfaces 50 of the PCB 40, and/or other factors described above with reference to FIGS. 1 IA-I IK. Other embodiments are within the scope and spirit of the invention. For example, due to the nature of software, functions described above can be implemented using software, hardware,

firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Further, while the description above refers to the invention, the description may include more than one invention. Having thus described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications and improvements are intended to be within the scope and spirit of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention's limit is defined only in the following claims and the equivalents thereto.

What is claimed is: