Abstract:
A module for automatic scrap wire isolating and removal is used in systems such as wire insulation lines for extricating scrap wires while minimally interfering with the mechanized wire insulation process. One such module includes a knife assembly with a knife, a scrap tray with a tilt plate for catching the scrap wire below the knife assembly, an accumulator with curved hooks oriented for catching and accumulating, one at a time, the wire and the scrap wire and rotatable for letting go, one at a time, of the wire and scrap wire, so as to allow the knife to completely separate the scrap wire from the wire. A lifting linkage in this module is operatively engaged with the tilt plate tilting it at an angle sufficient for the isolated scrap wire to slide off, whereby the scrap wire is removed.

Description:
REFERENCE TO EARLIER APPLICATION  
       [0001]     This application claims benefit from and incorporates by reference U.S. Provisional Application Ser. No. 60/516,066, filed Oct. 30, 2003, titled “Automated Scrap Wire Removal Method and Apparatus.” 
     
    
     BACKGROUND  
       [0002]     It is a common practice, in the automotive electric parts field and in the networking infrastructure field, to optimize cable quality by tandem wire drawing and extrusion. For example, local area network (LAN) cables are drawn to size and extruded in tandem with insulation. Then, in the automotive parts field, it is also common to package insulated wire in cardboard barrels or drums for subsequent payout into automotive wire harness assembly equipment.  
         [0003]     The amount of wire that can be packaged in the barrel depends on the outside diameter of the wire and the dimensions of the barrel. Typical amounts range from a minimum length of 30,000 ft to a maximum of 120,000 ft. Since a common harness length is anywhere from 3 ft to 20 ft, many harnesses can be made from a single barrel of wire.  
         [0004]     Typically, wire insulation material such a plastic is extruded to form the outer layer of the insulated wire. During this process, application of the insulation material to the surface of the wire can fail and defects in the insulation can occur. With such defects, an improperly insulated wire is likely to fail diameter, spark, and other tests for defects. Hence, it is important to isolate these defects by, among other things, removing the damaged sections of the insulated wire. It is most advantageous to remove these damaged wire sections prior to feeding the insulated wire into the harness assembly equipment.  
         [0005]     The present practice of removing the defective insulated wire sections involves intervention by the machine operator. Human intervention in the fast speed, mechanized wire insulation process for the purpose of removing defective sections is difficult and not completely effective. Clearly, manual operation cannot address all the various situations that may occur during routine operation of the insulating and coiling process. One such difficult situation is the occurrence of multiple faults in quick succession.  
         [0006]     In view of the foregoing, automation of the removal process promises to be a more effective approach to extricating the defective wire sections. Accordingly, there is a need to more fully automate the wire insulation process, particularly as it relates to the scrap wire removal process.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention addresses these and related needs. In particular, the present invention offers a new approach to scrap wire removal. In essence, the new approach provides automatic scrap wire removal method and system.  
         [0008]     Various aspects of the present invention contribute to the automation of the removal process and its improved results. Among others, these include: a knife assembly operative as a bi-directional wire cutting means; a scrap tray operative to snag the defective wire and extricate it from the insulating line; a scrap tray lifting mechanism operative to lift the scrap tray for dumping the scrap wire into a scrap container; and a wire accumulator with a pallet and curved hooks operative to collect the wire without a defect (good wire) as it accumulates on the pallet while the scrap wire is being extricated.  
         [0009]     In one implementation, a module for automatic scrap wire isolation and removal that includes a knife assembly with a knife and a scrap tray with plates for catching the scrap wire below the knife assembly. The tray is configured with a tilt plate. This module also includes an accumulator with hook-shaped arms (pallets) that are curved for lassoing and accumulating the scrap wire and keeping it from falling off the accumulator until it is cut by the knife from the wire bellow. The curved hooks are rotatable momentarily in one direction for letting go of the scrap wire. The curved hooks are rotatable also in the other direction for lassoing and accumulating the good wire above the scrap wire until the scrap wire engages the knife and is isolated from the good wire above. The module further includes a lifting linkage operatively engaged with the tilt plate, the lifting linkage being extendable to tilt the tilting plate at an angle sufficient for the isolated scrap wire to slide off the tilt plate, whereby the scrap wire is removed.  
         [0010]     Another aspect of the invention is the method contemplated for implementing the scrap wire isolation and removal. In this method, after guiding a wire to an accumulator via a tester, the accumulator is commanded to close when the tester indicates a defect in the wire. Upon closing, the accumulator snags the scrap wire so that it hangs from the accumulator and starts accumulating more of the scrap wire above that includes the defect. A command is sued to the reciprocating scrap tray to move to an active position and snag the wire hanging from the accumulator. While the accumulator is closed, a reciprocating knife is commanded to move in one direction and cut below the defect the scrap wire hanging from the accumulator to separate it from the good wire below. After the good wire is separated from the scrap wire above, it is free to fall but its end is urged to fall outside a container for collecting the good wire. This makes it possible to grasp the end of the falling wire and secure it to an outside surface of the container, whereby the end of the good wire is easily located.  
         [0011]     Next, the accumulator is commanded to open momentarily and release the accumulated scrap wire. The accumulator is open for a sufficient time to allow the entire scrap wire to fall bellow the reciprocating knife. When the accumulator closes again it snags the good wire above the scrap wire from the good wire above so that the scrap wire hangs down from the accumulator. While the accumulator is again closed, the reciprocating knife is commanded to move in an opposite direction and cut the scrap wire above the defect, thereby isolating the scrap wire and allowing it to fall onto the reciprocating scrap tray. Finally, the reciprocating scrap tray is commanded to move to a resting position, away from the coiling area, and tilt to dispose of the scrap wire.  
         [0012]     As can be appreciated, this approach has the advantage of more effectively extricating scrap wires while minimally interfering, if at all, with the mechanized wire insulation process. This and other features, aspects and advantages of the present invention will become better understood from the description herein and accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The accompanying drawings which, are incorporated in and constitute a part of this specification illustrate various aspects of the invention and together with the description, serve to explain its principles. The drawings include  FIGS. 1, 2  and three sets of diagrams, namely, the set of  FIGS. 3A-3D , the set of  FIGS. 4A-4J  and the set of  FIGS. 5A-5H .  
         [0014]     Typically, an item shown in different diagrams will have the same call out number in all the diagrams in which it is shown, and this applies to the drawings here. However, because the three sets of diagrams,  FIGS. 3A-3D ,  4 A- 4 J and  5 A- 5 H, respectively, represent engineering drawings of an actual embodiment, the call-out numbering scheme in these drawings follows an engineering convention different than that in  FIGS. 1 and 2 . Specifically, each set of the diagrams is treated individually with its own alpha numeric item-referencing sequence where in each set the items are numbered sequentially 1, 2, 3, . . . and A-Z. For example, a particular item # (e.g., ‘1’) references the same item (item  1 ) in all the diagrams within one set, but in different sets the particular item # references different items. Items referenced by letters include fastening means such as bolts, nuts, washers and screws. Moreover, in order to avoid duplication of an item in the parts list of the system (overall bill of materials), once a first instance of an item is called out, subsequent instances of that item, at other diagrams in the set, are referenced with the same call-out number along with a ‘REF’ indication. This indication clarifies that the item has been references originally at another diagram in the set.  
         [0015]     The drawings are briefly described as follows:  
         [0016]      FIG. 1  illustrate a wire insulation system;  
         [0017]      FIG. 2  illustrates in some detail the automatic scrap wire removal module of the wire insulation system;  
         [0018]      FIGS. 3A-3D  is a set of diagrams of an accumulator with the hook arms (pallets) in the open and closed positions, respectively;  
         [0019]     FIGS.  4 A-D is a set of diagrams of a scrap tray and lifting mechanism from various view points; and  
         [0020]      FIGS. 5A-5H  is a set of diagrams of a knife assembly from various view points. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     In view of the need to automate the wire insulation line more fully, the present invention provides an automated scrap wire removal system and method. In order to better understand the principles of the invention, the system and method are described using the illustration of a wire insulation line.  FIG. 1  is a diagram of the wire insulation line (the so called “wire insulation system”).  
         [0022]     In general, a typical wire insulating line consists of a bare wire payoff device  102 , the insulation equipment  104 , and a coiler  120 . As shown in more detail in  FIG. 1 , a wire insulation system preferably includes: a bare wire payoff mechanism  102 , an extruder  110 , a cooling means  112 , a pull-out capstan  114 , a spark tester  116 , a dancer  118 , a wire scrap removal module  124 , and an insulated wire take-up mechanism also referred to here as the coiler  120 . In addition, there are one or more wire reels (e.g.,  130 ), wire baskets or barrels  122 , and scrap wire containers (not shown). The scrap wire module will be described in more detail below.  
         [0023]     The wire payoff mechanism  102  is constructed for paying off wire from a reel (or spool)  130 , preferably in a controlled manner. For example, after the reel is placed into a payoff position, a wire tensioner is engaged to maintain wire tension and ensure continuous payoff. Optionally, one or more guide bars are engaged with the wire so as to keep it from jumping off the rollers as it is moved through toward the extruder.  
         [0024]     On the way out from the extruder, the insulated wire is cooled in a cooling area  112  and tensioned in the pull-out capstan (or simply capstan)  114 . The axis of the capstan  114  is preferably in a horizontal plane.  
         [0025]     In this system configuration, the spark tester  116  is positioned, after the capstan  114 , to receive the insulated wire output from the extruder  110 . Alternatively, the spark tester is integrated with the extrusion and rewind lines for detecting defects in the wire insulation. The spark tester  116  checks for faults in wire insulation and detects bare patches and pinholes. To that end, the spark tester includes high-voltage and ground electrodes. In particular, when the wire passes by the spark tester&#39;s high-voltage electrode, if the wire insulation is defective it allows a spark to jump to the ground electrode via the cable core. This type of phenomena results in increased current which when detected is indicative of the insulation defect. The insulation defect indication can be registered and presented down stream to other parts of the system and to the operator. The defective wire is then isolated from the good wire and discarded as a scrap wire, and the good wire is introduced to the coiler  120 . In the system of  FIG. 1  the coiler  120  and scrap wire removal module  124  are shown as separate components, making the scrap wire removal system  124  an option for the purchaser of a coiler  120 .  
         [0026]     The coiler  120  is a mechanism for packaging the wires into barrels  122 . While the payoff  102  feeds the bare wire  131  to the insulating line equipment, the coiler  120  “takes-up” the insulated wire  132  in barrels  122 . In the coiling process, the insulated wire  132  is continuously presented to the coiler at process speeds. This speed can, in one instance, range from 1,000 feet per minute to 4,000 feet per minute.  
         [0027]     At the coiler  120 , a rotating flyer assembly wraps the wire around a stationary capstan  126  while the dancer  118  provides the static or variable tension in the wire  132  as it is presented to the coiler. The convolutions (loops) of insulated wire are wrapped radially along the surface of the capstan by a deflector roller that rotates together with the flyer Assembly. When the convolutions are displaced beyond the cylindrical surface of the capstan, because capstan axis is preferably in a vertical plane, they fall under by the action of gravity toward a barrel  122  located directly below the capstan  126 A.  
         [0028]      FIG. 2  is a diagram of a coiler module  106  in which the coiler scrap removal system  124  is an integral part of the module. In this configuration, the coiler is located above a barrel  122  built as a cardboard wire basket. To facilitate the circular accumulation of the insulated wire, the barrel is placed on a rotating turntable  142 . The coiler is running at a high speed dropping insulated wire  132  in a helix pattern from the capstan toward the cardboard wire barrel  122 . While rotating, the barrel receives the insulated wire  132   a  which collects circularly around the barrel&#39;s vertical axis.  
         [0029]     In order to make a barrel change, when the barrel  122  becomes full, a device called an accumulator  134 , is located between the capstan and the barrel. The accumulator is employed to intercept and collect the falling loops of wire  132   a , allowing time to replace the full barrel with an empty one. The accumulator  134  is instrumental in also allowing the automatic scrap wire removal. Importantly, the accumulator works in tandem with the scrap tray  138  and scrap tray lifting mechanism  140  to facilitate removal of the scrap wire  132   c  (more detailed diagrams of an accumulator are provided in the set of  FIGS. 3A-3D ).  
         [0030]     For the purpose of this discussion we assume that during operation a spark fault is detected in the wire  132  upstream of the coiler. The indication of this defect is registered and distributed downstream and to the operator. As a result, the accumulator  134  closes and starts collecting the defective wire in a lasso fashion on its pallets  146  (hook-shaped arms). Indeed, once the defect (spark fault) is detected minimal but sufficient length of the (defective) wire is collected on the pallets of the accumulator (hook-shaped arms). As shown in  FIGS. 2 and 3 A, the hook-shaped arms  146  capture the wire loops preventing them from falling below the accumulator. Thus, the helical wire loops  132  that continue falling from the capstan collect at the accumulator  134 . The good wire portion  132   b  that passes the accumulator just as it closes remains hanging vertically from the accumulator and extending toward the barrel below.  
         [0031]     Additionally, in response to receiving an indication of the defective wire, the scrap wire tray  138  slides into place beneath the accumulator. As it moves, the scrap wire tray aligns itself with the vertical axis  148  of the coiler, above the barrel and below the accumulator so as to properly engage the vertically hanging wire  132 B. The scrap wire tray moves on bearings  150  mounted on slide rods  152  and is shifted to this position by a pneumatic band cylinder located below it (more detailed diagrams of a scrap tray and lifting mechanism are provided in the set of  FIGS. 4A-4J ).  
         [0032]     Once the scrap wire tray  138  is in position above the barrel  122 , the leading edge of the tray table snags the vertically hanging wire  132   b . Below the accumulator  134 , the vertically hanging wire  132   a  passes through a knife assembly  136  (diagrams of a knife assembly are provided in the set of  FIGS. 5A-5H ). The knife assembly is used to cut the defective wire from the good wire by making two passes. The first pass cuts the insulated wire below the defective wire area separating it from the good wire downstream (below). The second pass cuts above the defective wire area separating it from the good wire that follows from above.  
         [0033]     Specifically, the reciprocating knife can cut both ways with the bi-directional movement of the knife assembly. On command, the system energizes the knife assembly  136  for movement in one direction. As the knife makes the first pass in this direction it cuts the hanging wire below the defective wire area to detach the good wire  132   b  downstream (below) from the defective wire  132 . The free end of the good wire drops down with gravity and it leaves behind the bad wire  132  hanging vertically from the accumulator (at or above the level of the knife). Because of the way the scrap wire tray  138  engages the good wire  132   b , the end of the good wire falls to the outside of the barrel.  
         [0034]     The machine operator can grab the falling end of the good wire, bend it over the top edge of the barrel and secure it to the side of the barrel (using tape or other means). All the while, the accumulator  134  collects the defective insulated wire  132  and, as a result, the insulation line upstream is not interrupted.  
         [0035]     Preferably, the accumulator  134  reopens shortly after the wire is cut so as not to accumulate too much good wire  132   a  beyond the defect. The loops, or “donut,” of accumulated defective wire drop from the accumulator onto the scrap wire tray  138 . Shortly thereafter, the wire accumulator  134  closes again for capturing good wire  132   a  as it continues to drop from the capstan above.  
         [0036]     The scrap wire segment with the entire defective area has now dropped below the knife assembly onto the scrap removal tray  138  and is cut isolating the scrap wire segment from the wire hanging from the accumulator. While the scrap wire segment is being removed, the good wire  132   a  starts accumulating on the closed pallets (hooked shaped arms)  146  of the accumulator as the good wire continues to fall from the coiler capstan.  
         [0037]     After the knife has completed its second pass, and the accumulator  134  closes, the scrap wire tray  138  carrying the scrap wire segment is pneumatically moved to its resting position outside the coiler  106 . When the scrap wire tray is at the end of its stroke (e.g., 40″ stroke), a pin  154  on the scrap wire tray is automatically engaged with the scrap tray lifting mechanism  140 .  
         [0038]     As the scrap tray lifting mechanism  140  is energized, it tilts the scrap wire tray  138 . The tilting angle  158  is sufficiently high to allow the scrap wire segment to slide off the scrap wire and fall with gravity into a scrap wire container  156  below.  
         [0039]     It can be appreciated that since this process can complete in as little as 6 seconds the removal is sufficiently fast to avoid detriment to the wire insulation process upstream. The automatic scrap wire removal system just described is implemented with details such as those shown in the sets of diagrams in  FIGS. 3A-3D ,  4 A- 4 J and  5 A- 5 H.  
         [0040]     Starting with the set of diagrams that describe the accumulator  134 ,  FIGS. 3A-3D , we note in  FIG. 3A  the two pallet positions, open and closed, on the left and right sides of the diagram, respectively.  FIG. 3B  is a table containing the bill of materials for the accumulator that would normally accompany the engineering diagrams from the manufacturer. There is a correlation between the table and the engineering diagrams where the various items referenced in the diagrams are identified in the table. Based on this table, and the top view as shown in  FIG. 3C , the accumulator plate (item  1 ) is designed to support the pallets (item  2 ) that collect the wire loops when the pallets are in the closed position. The linkage assemblies (items  3 ) connect the pallets along a circle on the plate and their (clockwise-counterclockwise) movement switches the pallets&#39; position back and forth between its open and closed positions. In this configuration, the linkage-pallet connection points form a smaller inside circle, e.g., 27½″ dia., of the accumulator plate. In  FIG. 3D , the side view of the accumulator shows the plate with four pallet connections passing through and the fastening means (items A and B) to keep them in place. In this accumulator design, seven linkage assemblies, fastened to the pallets using fasteners and spacers (items  7  and E and F), connect the pallets and operate to move them as described before. Because the bars in the linkage assembly are stiff, their movement follows a straight line but proximate to the aforementioned circle in the clockwise-counterclockwise direction. When the linkage assemblies move clockwise, the pallets switch to the closed position and start collecting the wire on the pallets in a lasso fashion.  
         [0041]     The next set of diagrams,  FIGS. 4A-4J , illustrates the scrap tray and lifting mechanism assembly (e.g., items  138  and  140 ,  150 , etc. in  FIG. 2 ).  FIG. 4A  is a small scale diagram of the various components that, collectively, make up a scrap tray and lifting mechanism for a right handed coiler. The table in  FIG. 4B  is the bill of materials for the scrap tray and lifting mechanism assembly with reference numbers and letters that match and help identify the components in the diagrams. Various components in this assembly are shown in a separate diagrams of a larger scale.  
         [0042]      FIG. 4C  shows the reciprocating plate (item  2 ) of the movable scrap tray in active scrap removal position under the accumulator (left) and in resting position away from the coiling area (lighter, dotted lines on the right). The movable scrap tray is supported by a rail assembly on each side (items  8  and  9 ). A scrap catcher (item  3 ) is fitted on the tilting plate (item  1 ) to hold the scrap wire(s) in place on the tilting plate while being transported toward the scrap wire disposal location at the resting position. A lift linkage assembly (item  5 ) is activated by a lifting pin bracket (item  22 ) that engages with it when the scrap tray approaches the resting position. The lifting pin bracket is located at the far side of the tilting plate so that it is proximate to the lift linkage when the scrap tray assembly moves to its resting position and engages the lift arm of the lifting mechanism. The lift linkage is activated to tilt the tilt plate (not shown here) at an angle that allows the scrap wire to slide down with gravity into the scrap wire container (item  156  in  FIG. 2 ).  
         [0043]      FIG. 4D  shows a front view of the scrap tray, in both positions, with the reciprocating plate (item  2 ), tilt plate (item  1 ) and scrap catcher (item  3 ). The plate stop with the shock absorber (item  21 ) acts to mechanically stop the scrap tray when it reaches the active scrap removal position, (see also  FIG. 4E ). In the active scrap removal position, as shown in  FIG. 4E , the reciprocating plate (item  2 ) engages the wire between it and the squeezer plate (item  12 ). The wire is squeezed between the two plates (items  2  and  12 ).  FIGS. 4F-4H  show the various brackets and support structures for the reciprocating plate.  FIGS. 4I and 4J  show the lift linkage and scrap wire discarding mechanism in operation.  
         [0044]     In order to isolate the defective wire segment the knife assembly is built to perform two cuts as described above. The next set of diagrams,  FIGS. 5A-5H , show the wire cutter assembly for use with the spark fault scrap removal system. Again, this set includes an overall diagram in  FIG. 5A  and a parts list table in  FIG. 5B . More specific diagrams for the various components start with  FIG. 5C  which shows the knife assembly from the bottom looking up. The main plate (item  15 ) is the structure supporting the knife assembly. The knife ring (item  14 ) defines the circular space in the main plate through which the wire passes as it hangs down from the accumulator. The knife block (item  5 ) is reciprocating and shown as being movable both ways, as represented in the diagram by the arrows (in one side, the knife block is shown in dotted line). As the reciprocating knife block completes a stroke in either direction, its proximity is sensed by a proximity switch (items  38 ) located at each of the sides. The knife block travels along a linear motion system (item  27 ) supported at each end by that motion system. The knife block is driven by a drive assembly that includes a motor-belt configuration (items such as  29 ,  30 ,  33 ,  34 , etc.) and the torque is transferred to the knife block via a shaft (item  16 ). Finally,  FIGS. 5D-5H  provide a closer and more detailed view of the drive assembly, proximity switch connections, and other support and fastening structures.  
         [0045]     The foregoing description in conjunction with the aforementioned three sets of drawings applies to a particular implementations of the scrap wire removal module. However, although the various aspects of the present invention have been shown and described in considerable detail with reference to particular implementations thereof, other implementations are possible. Therefore, the spirit and scope of the present invention should not be limited to the illustration and description of the preferred versions contained herein.