Abstract:
There is provided a feeder device for a pick-and-place machine used to surface mount connectors on printed circuit boards. The feeder is designed for use with matrixes of connectors, such as pin headers. The feeders, with the proper conversion kits, can be configured to feed any type and/or size of the connector. Individual connectors are separated from the matrix by the feeder using a rotating clamping device. Preferably, the feeders are microprocessor controlled, use an edge conveyor to transport the strips to the pick point, and pneumatic cylinders to break each pin header from the strip.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention generally relates to devices and methods for mounting components on printed circuit boards. For specifically, this invention relates to feeder devices for surface mount technology placement machines and methods of using same.  
           [0003]    2. Description of the Prior Art  
           [0004]    Surface mounting technology (“SMT”) is used for creating printed circuits having components that are soldered to the board without using holes. The result is higher component density, allowing for smaller printed circuit boards.  
           [0005]    In general, a feeder will supply a component, such as a surface mountable connector, to the pick-up head of a placement machine, which places the component on a printed circuit board (PCB). The components to be feed and placed may be prepackaged in a variety of formats, including reels and trays. Feeders are typically designed to feed one format of pre-packaged components.  
           [0006]    The purpose of the feeders is to handle the pin header strips as an input, and present individual connectors to the placement machine as an output. It is envisioned that the individual pin headers at the output will be picked by nozzles that come down over one or more pins of the header and lift the individual pin headers from the feeder by vacuum.  
           [0007]    In general, feeders should be designed to feed the pin headers reliably, quickly, and accurately. The feeders should be as compact as possible, particularly in width, so as not to use any more feeder slots than necessary. They should be able to feed down to the last pin header in the feeder. They should be easy for the operator to load with pin header strips and easy to operate.  
           [0008]    Moreover, feeders should be able to be adapted to many placement machines, using as many common parts as possible. The difference from placement machine to placement machine would be the mounting design, the pick point location, and any clearance requirements. The goal would be to make a design that would be able to be adapted as a minimum, to several widely used placement machines, such as Celtronix, Fuji IP/QP, Panasonic MPAV2/MPAG3, Philips Eclipse/GEM, Quad standard mount, Robodyne, Sanyo TIM-1100/1000, Sanyo TCM-V550/V503, Siemens Siplace, and Universal GSM/OFA  
           [0009]    In addition, feeders should be low maintenance, and be convertible for different length pin headers (2 pin length to 12 pin length) and for either a single or a double row of pins. The conversion process should be able to be performed by a line set up operator, and not require a machine maintenance technician.  
         SUMMARY OF THE INVENTION  
         [0010]    It is an object of the present invention to provide a feeder device for handling matrixes of connectors as an input, and present individual connectors to the placement machine as an output.  
           [0011]    It is also an object of the present invention to provide such a feeder device that is reliable, quick, and accurate, as well as compact, easy to load, and easy to operate.  
           [0012]    It is a further object of the present invention to provide a feeder device that is adaptable to many placement machines, using as many common parts as possible.  
           [0013]    It is yet another object of the present invention to provide a feeder device that is easily and quickly convertible for different length pin headers and for either a single or a double row of pins.  
           [0014]    These and other objects of the present invention are accomplished by a feeder device as described herein. A feeder device according to the present invention is designed for use with matrixes of connectors, such as pin headers. The feeders, with the proper conversion kits, can be configured to feed any type and/or size of the connector. Individual connectors are separated from the matrix by the feeder using a rotating clamping device. Preferably, the feeders are microprocessor controlled, use an edge conveyor to transport the strips to the pick point, and pneumatic cylinders to break each pin header from the strip. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a right side plan view of a feeder device according to the present invention;  
         [0016]    [0016]FIG. 2 is a top side plan view of the feeder device of FIG. 1;  
         [0017]    [0017]FIG. 3 is a bottom side plan view of the feeder device of FIG. 1;  
         [0018]    [0018]FIG. 4 is a left side plan view of the feeder device of FIG. 1;  
         [0019]    [0019]FIG. 5 a  is a left side detail plan view of a clamp for use in the feeder device of FIG. 1;  
         [0020]    [0020]FIG. 5 b  is a rear view of the clamp of FIG. 4 a;    
         [0021]    [0021]FIG. 6 is a left side plan view of the clamp of FIGS. 4 a  and  4   b  during operation thereof;  
         [0022]    [0022]FIG. 7 is a detail plan view of the transport section of the feeder device of FIG. 1 showing a matrix of pin headers being guided thereon;  
         [0023]    [0023]FIG. 8 is a top side plan view of a matrix of pin headers that is preferably fed and separated by the feeder of FIG. 1;  
         [0024]    [0024]FIG. 9 is a left side plan view of the matrix of FIG. 6 showing the scribe lines therein;  
         [0025]    [0025]FIG. 10 is a wiring diagram for a feeder device according to the present invention; and  
         [0026]    [0026]FIG. 11 is a plumbing diagram for a feeder device according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]    Referring to the drawings and, in particular, FIG. 1, there is illustrated a feeder device according to the present invention, generally indicated as reference number  1 . The feeder is composed of four major sections, the chassis section  12 , the breaker section  14 , the transport section  10 , and the control section  16 . In addition, feeder  1  may also be provided with any suitable equipment and accessories, for example, T-slots for mounting accessory hardware. Please note, when referring to the feeder, the left and right sides are as viewed from control section  16 . Also, control section  16  is also considered the “rear” of the feeder; the breaker section  14  is at the “front” of feeder device  1 .  
         [0028]    Referring to FIG. 2, chassis section  12  has left sidewall  22 , right sidewall  23 , and movable rail  24 . The distance between right sidewall  23  and movable rail  24  defines header width space  25 . In addition, chassis section  12  may have a magnetic bar  28  (see FIG. 1) adapted for attachment to a placement machine, as discussed below.  
         [0029]    Referring to FIGS. 1 through 4 b , breaker section  14  has clamp  35 , breaker linkage  36 , breaker cylinder  37 , clamp cylinder  38 , clamp force cylinder  39 , header row spacer  40 , left breaker support  41 , right breaker support  42 , movable rail header support  43 , clamp pusher bar  44 , clamp torsion springs  45 , breaker cylinder extend flow control valve  54 , breaker cylinder retract flow control valve  55 , clamp cylinder retract flow control valve  56 , link/breaker connection pin  57 , at least one breaker pivot bearing  58 , and clamp pressure bar mount  59 . Optionally, breaker section  14  may have vacuum cleaning ports  60  adapted to remove dust and other debris from break section  14 .  
         [0030]    Referring in particular to FIG. 3, transport section  10  has drive motor/pulley  61 , drive belt  62 , conveyor belt drive shaft  63 , at least one conveyor belt  64 , at least one conveyor belt idler bearing  65 , and drive shaft bearing holder  66 . Alternatively, transport section  10  may have any suitable means for transporting matrix  80  to break section  14 , such as slip-driven rollers. Transport section  10  is preferably relatively quiet, durable, energy efficient, and designed with sealed gears and bearings to resist contamination.  
         [0031]    Transport section  10  also preferably has a header-in-place sensor  72  (e.g. a fiber optic), and a placement machine nozzle sensor  74 . Sensors  72  and  74  can be compact size photo-electric sensor type, with a sensitivity adjuster, long sensing distance, compatibility with 12-24 V DC operation, NPN and/or PNP outputs, and through beam. Moreover, such sensors can be diffuse reflective, convergent reflective, or narrow view reflective with or without IP 67  IEC protection rating.  
         [0032]    Preferably, for ease of use, sensors  72  and  74  have two positions, towards the front or towards the rear of feeder  1 . The proper position for sensors  72  and  74  for double row headers is towards the front of the feeder. For single row headers, sensors  72  and  74  should be towards the rear. Also for ease of use, sensors  72  and  74  may be protected by appropriate sensor housings. LED indicators can be used to tell whether sensor  72  and  74  are operating correctly. LED indicators can also be used to tell whether sensor  72  and  74  are operating incorrectly, for example, due to soiled fibers, misalignment, damaged fiber, and/or fiber not plugged into amplifier.  
         [0033]    Sensors, such as sensors  72  and  74  may be located at any suitable location on or adjacent to the feeder of the present invention. For example, sensors  72  and  74  may be disposed on breaker section  14  or controller section  16 .  
         [0034]    Control section  16  has control board (not shown). The control board may include any suitable feature, such as an amplifier with automatic response time setting, auto gain setting, sixteen-memory settings, and/or analog output hold. Control section  16  may optionally have an ISAN master bus controller, an eight-channel analog to digital converter, a real-time clock, a keypad, an LCD interface, an infrared remote receiver, an RS232 serial interface, and/or EEPROM program/data storage. Moreover, the control board is preferably programmable to provide simple repetitive sequence signals or complex interactions between the motor and the sensors. Therefore, the preferred control board has a plurality of configurable and/or expandable input and/or outputs, programmable logic controllers, silicon carbide insertion panels, a memory size of seven hundred words CMOS, high speed counting of two kilohertz (kHz) per second, and/or switches and indicators enabling the simulation of input and output events. Also present in control section  16  may be power line protected, fold-back power supplies that are switchable 115/230 V, 50/60 hertz (Hz) operation. A five-digit LED  76  can be employed by control section  16  to display the measurement values or settings of sensors  72  and  74 .  
         [0035]    Preferably, most of the components in feeder  1  are made from high-performance, static-dissipating materials as defined by MIL B 81705c. In addition, metal surfaces are preferably are provided with at least one nickel plated path to ground.  
         [0036]    Feeder device  1  may be converted to feed matrixes of different widths and lengths, as well as pin height.  
         [0037]    The width of header row spacer bar  40  depends on whether the header has a single row or a double row. For a single row header, header row spacer  40  is about 0.250″ wide, and for a double row header, header row spacer  40  is about 0.180″ wide. Header row spacer bar  20  is held to the top of breaker section  14  by two button head screws, located on each side of clamp  35 . If the width (i.e., the number of pins) is being changed, header row spacer  40  is changed. In addition, the positions of sensors  72  and  74  are specific for the header row spacer bar  40 .  
         [0038]    Pin length can range from {fraction (1/4)}″ to 1″. If the pin length is different, then the placement of sensors  72  and  74  are changed.  
         [0039]    As stated above, feeder  1  may be adapted to feed and break any suitable matrix of connectors. Preferably, feeder  1  is adapted to feed and break a matrix of pin headers for surface mounting on a PCB. Such a preferred matrix of pin headers is described in co-pending U.S. patent application Ser. No. 09/166,632, which is incorporated herein by reference in its entirety. In brief, referring to FIGS. 6 and 7, the preferred matrix of pin headers has a PCB base with square pins. The preferred matrix is provided in a strip form, with individual pin headers having either a single or a double row of pins. Scribe lines in the matrix define the size of the individual pin headers. Preferably, the matrix is scribed on both the top and bottom surfaces thereof. The individual headers are broken from the matrix one at a time and presented to the nozzle of the placement machine to which feeder  1  is associated.  
         [0040]    Referring again to FIG. 1, feeder device  1  may be installed on a placement machine using any suitable mounting structure. As stated above, feeder device  1  may have magnetic bar  28 . In addition, feeder device  1  may use a latch. Preferably, the mechanical interface with the host machine varies by host machine model. For example, the feeder device may have slots and/or bushings to engage rows of dowel pins, such as those used in placement machines manufactured by Siemens and sold under the trademarks Siplace F4 and F5. As another example, feeder device  1  may have ribs and/or similar structures to engage grooves, such as those used in placement machines manufactured by Fuji and sold under the trademark IP.  
         [0041]    To use feeder  1 , a matrix  80  is placed on conveyor belt  64  at the rear of feeder  1 . Preferably, as long as there is room on conveyor belt  64 , a matrix  80  can be loaded thereon at any time during the operation of feeder  1 . Once matrix  80  is loaded, conveyor belt  64  transports matrix  80  until the leading edge of matrix  80  contacts header row spacer  40 . At that point, the leading row of pins on matrix  80  blocks header-in-place sensor  72 . A signal from header-in-place sensor  72  stops conveyor belt  64 . Conveyor belt  64  briefly reverses direction to relieve any pushing pressure on matrix  80 .  
         [0042]    As soon as the leading row of pins on matrix  80  blocks header-in-place sensor  72 , clamp cylinder  38  retracts, causing clamp  35  to close on the top of the first pin header. Clamp  35  is closed by torsion springs  45 . The amount of pressure exerted on the first pin header is preferably adjustable by a clamp force cylinder  39 .  
         [0043]    Referring to FIG. 5, once clamp  35  is closed on the first pin header, clamp  35  and breaker cylinder  37  retract. Since clamp  35  is connected to breaker cylinder  37  by a breaker linkage  36 , the resulting action is that clamp  35  rotates around breaker pivot bearing  58 . The lead pin header also rotates, since it is closed within clamp  35 , and breaks free from the rest of matrix  80 . The “snap” action of breaker section  16  needs to be fairly fast, but the impact at the end of stroke should not be violent. Alternatively, once the lead pin header is broken from matrix  80 , the freed pin header can be dropped and/or raised relative to matrix  80 , for example, about 0.1 inch, in order to ensure that the freed pin header is completely separated from matrix  80 . Preferably, feeder device  1  has an appropriate flow controller or controllers to adjust the speed of the operation of breaker section  16 . As soon as retraction of breaker cylinder  37  is detected by breaker cylinder retract sensor  51 , clamp cylinder  38  extends, which returns the freed pin header to a substantially level position. The freed pin header is held in place by the force of clamp torsion springs  25  and/or by vacuum clamping ports (not shown). Clamp force cylinder  39  retracts and feeder  1  waits for the placement machine to come and pick the freed pin header. At any time during this operation, optionally provided vacuum cleaning ports may be employed to remove dust and other debris from break section  14 .  
         [0044]    The nozzle of the placement machine blocks the placement machine nozzle sensor  74  when it approaches the top if the freed pin header. When this happens, clamp cylinder  38  extends, unclamping the pin header, so that the freed pin header can be removed by the nozzle. Optionally, when vacuum clamping ports are used to hold the freed pin header, the vacuum ports are pressurized to agitate the pin header from its -close proximity to the matrix  80  and also to move the freed pin header into the nozzle of the placement machine.  
         [0045]    As soon as both placement machine nozzle sensor  74  and header-in-place sensor  72  are unblocked, conveyor belt  64  is driven and the next pin header in matrix  80  is stopped against header row spacer  40 .  
         [0046]    The feeder&#39;s ease of loading, along with its large capacity, decreases the amount of time spent on refills and results in smoother operation interactions with the machines. The feeder&#39;s narrow design provides high feeder density to the host machine.  
         [0047]    The foregoing represents a description of a preferred embodiment of the present invention. Variations and modifications of the embodiments described and shown herein will be apparent to persons skilled in the art, without departing from the inventive concepts disclosed herein.