The invention relates to an apparatus and methods for making a tubular braid comprising a plurality of filaments, particularly small diameter wires.
Braiding machines, have long been used in industry, for example, to braid metallic wire into electrical or electronic cable as a protective armor or into hydraulic hose and cordage as a load bearing structure or into rope, either metallic or non-metallic.
The two main kinds of braiding machines presently used are maypole-type braiding machines and internal cam rotary-type braiding machines, The maypole-type machine uses a plurality of spool carriers to carry filament bobbins in serpentine-like paths about a track plate. The track plate consists of two separate paths: each path 180 degrees out of phase from the other. One path moves clockwise, while the other path moves counter clockwise. Horn gears or notched rotors on the deck create the serpentine path. Half the earners travel in the first path around the braiding point following one serpentine path created by the horn gears while the other half of the carriers travel in the second path, in the opposite direction around the braiding point. As the two sets or carriers travel in opposite directions around the braiding point, each set crosses the path of the other and the strands leaving the filament bobbins are interwoven as they converge to the braiding point. The speed of these machines is limited by the inertia of the carriers and/or changes in tension on the filaments resulting from the continuously changing radial movement towards and away from the point of braid formation.
These types of braiding machines, however, are generally limited to production of braids using lower filament count and/or generally large filaments. Typical braid structures of small filaments are 72, 96 and 144 in a one-over, one-under braid pattern. These same machines, generally of the maypole variety with horn gears and carriers, may also be used to produce 144, 192 or 288 braids of two-over, two-under construction. Very large “Megabraiders” have been, manufactured with up to 800 carriers that will produce high filament count braids. See http://www.braider.com/About/Megabraiders.aspx These Megabraiders, however are generally used for large structures and are not suitable for most medical applications that require construction with fine wires that have low tensile strength.
The internal cam rotary type braiding machine, known as the Wardwell Rapid Braider, uses a high-speed braiding process. This type of machine uses a plurality of lower carrier members and a plurality of upper carrier members, which travel past each other in continuous circular paths centered about the braid axis, going in opposite directions. As the upper and lower carriers travel past each other in opposite directions, strands from bobbins on the lower carriers are intertwined with strands from bobbins on the upper carriers. Deflectors are used to lift strands of the lower carriers up and over strands from the upper carriers, so that only the strands of the lower carriers are alternately passed over and under strands of the upper carriers to create the interwoven pattern. The Wardwell Braider, however, becomes unreliable when trying to braid strands or filaments of material, particularly very fine wire materials, having extremely small diameters. The rotary technique used therein produces so much tension on the very small diameter materials, particularly at one stage of the braiding process, that such extremely fine filaments tend to break, requiring that the machine be stopped.
Thus, it would be desirable to provide a braiding machine and process capable of manufacturing high wire count tubular braids of small diameter filaments without breakage.
The braiding apparatus described herein provides improved means of manufacturing high wire-count (also described as high picks per inch or PPI) tubular braids of small diameter filaments, and is particularly useful for the production of fine wire metallic alloy (e.g. nitinol, cobalt-chrome and platinum-tungsten) for medical applications.
Some embodiments of a braiding machine include a disc defining a plane and a circumferential edge, a mandrel extending from a center of the disc and generally perpendicular to the plane of the disc, a plurality of catch mechanisms positioned circumferentially around the edge of the disc, and a plurality of actuators adapted to move the plurality of catch mechanisms in a substantially radial direction relative to the circumferential edge of the disc. The mandrel is adapted to hold a plurality of filaments extending radially from the mandrel toward the circumferential edge of the disc and each catch mechanism extends toward the circumferential edge of the disc and is adapted to engage a filament. The point at which each filament engages the circumferential edge of the disc is separated by a distance d from the points at which each immediately adjacent filament engages the circumferential edge of the disc. The disc and the plurality of catch mechanisms are configured to move relative to one another to rotate a first subset of the filaments relative to a second subset of filaments to interweave the filaments. The disc may be adapted to rotate around an axis perpendicular to the plane of the disc, for example, in discrete steps of distance 2d. Alternatively, the plurality of catch mechanisms may be adapted to rotate around an axis perpendicular to the plane of the disc, for example, in discrete steps of a distance 2d.
In some embodiments, the braiding machine may be loaded with a plurality of filaments extending radially from the mandrel towards the circumferential edge of the disc. Here, each of the plurality of filaments contacts the circumferential edge of the disc at a point of engagement which is spaced apart a discrete distance from adjacent points of engagement. In some embodiments, the filaments may be wires. For example, the wires may be a plurality of fine wires having a diameter of between about ½ mil to 5 mils.
In some embodiments, the circular disc may have a plurality of notches radially spaced apart around the circumferential edge for holding individual filaments against the circumferential edge. For example, in some embodiments, the circumferential edge of the disc may have between about 100-1500 notches, alternatively between about 100-1000 notches, alternatively between about 100-500 notches, alternatively between about 100-300 notches, alternatively 108, 44, 288, 360, or 800notches. Some embodiments may further include a filament stabilizing elements, such as a cylindrical drum positioned on the second side of the disc and extending generally perpendicular to the plane of the disc. The drum may have a plurality of grooves extending longitudinally around the circumference of the drum in which individual filaments each rest with a different groove. In some embodiments, individual tensioning elements may extend from each of the plurality of filaments. The tensioning elements may each be configured to apply between about 2-20 grams of force to a filament. In some embodiments, the tensioning elements may each be configured to apply a force to a filament that is inversely proportional to the filament diameter. For wire sizes between 0.00075 to 0.0015 inches, the tensioning element may apply a force that is governed by the following equation:
F
T=˜8000 Dw+16
where Dw is the wire diameter in inches and
FT is the force in grams
In some embodiments, the actuator may be coupled to a plurality of catch mechanisms and configured to collectively move the plurality of coupled catch mechanisms. In some embodiments, the catch mechanisms are hooks, such as double headed hooks. In other embodiments, the catch mechanisms, and actuators may be angled relative to the plane of the disc.
Some embodiments of a braiding machine include a disc defining a plane and a circumferential edge, a mandrel extending from a center of the disc and generally perpendicular to the plane of the disc, a plurality of filaments extending from the mandrel toward the circumferential edge of the disc, and a plurality of catch mechanisms positioned circumferentially around the edge of the disc. The mandrel holds the filaments such that each filament contacts the circumferential edge of the disc at a point of engagement which is spaced apart a discrete distance from adjacent points of engagement. Each catch mechanism extends toward the circumferential edge of the disc and is adapted to engage a filament and pull the filament away from the circumferential edge of the disc in a generally radial direction.
In some embodiments, the points of engagements on the circumferential edge of the disc comprise a plurality of notches radially spaced apart around the circumferential edge. The drum may have a plurality of grooves extending longitudinally around the circumference. For example, in some embodiments, the drum may have between about 100-1500 grooves between about 100-1500 grooves, alternatively between about 100-1000 grooves, alternatively between about 100-500 grooves, alternatively between about 100-300 grooves, alternatively 108, 144, 288, 360, or 800 grooves. In some embodiments, each of the plurality of filaments rests within a different notch.
In some embodiments, the pluralities of catch mechanisms are coupled to a plurality of actuators that are actuated to pull the catch mechanisms away from the circumferential edge of the disc in a generally radial direction. Each actuator may be coupled to a single catch mechanism. Alternatively, each actuator may be coupled to a plurality of catch mechanisms and configured to collectively move the plurality of coupled catch mechanisms. In some embodiments, the catch mechanisms each comprise a hook, such as a double headed hook. In other embodiments, the catch mechanisms and actuators may be angled relative to the plane of the disc. In some embodiments, the angulation of the actuators relative to the plane of the disc may be between about 15° and 60°.
In some embodiments, the disc and the plurality of catch mechanisms are configured to move relative to one another to rotate a first subset of the filaments relative to a second subset of filaments to interweave the filaments. The disc may be adapted to rotate around an axis perpendicular to the plane of the disc, for example, in discrete steps of a distance 2d. Alternatively, the plurality of catch mechanisms may be adapted to rotate around an axis perpendicular to the plane of the disc, for example, in discrete steps of a distance 2d.
Some embodiments of a braiding machine include a computer program embodied in a non-transitory computer readable medium, that when executing on one or more computers provides instructions to engage a subset of the plurality of filaments and to move the disc and the plurality of catch mechanisms relative to one another in discrete step.
In some embodiments, a motor configured to rotate the plurality of catch mechanisms around an axis perpendicular to the plane of the disc is provided. Alternatively, a motor configured to rotate the plurality of catch mechanisms around an axis perpendicular to the plane of the disc may be provided.
The plurality of catch mechanism may comprise a plurality of books. Each actuator may be coupled to a plurality of catch mechanisms. Alternatively, each actuator may be coupled to a single catch mechanism. In some embodiments, a first subset of actuators may be individually coupled to a plurality of single catch mechanisms and a second subset of actuators may each be coupled to a plurality of catch mechanisms.
In some embodiments, the computer program may include instructions for moving the disc and plurality of catch mechanisms relative to one another to create a one over, one under braid pattern. Alternatively, the computer program may include instructions for moving the disc and plurality of catch mechanisms relative to one another to create a one over, three under braid pattern. Other computer programs may include instructions for sequentially moving a subset of the plurality of catch mechanisms and rotating the disc and catch mechanisms relative to one another to create a one-over, one-under (diamond) braid pattern.
Some embodiments of a braiding machine include a disc defining a plane and a circumferential edge, a mandrel extending from a center of the disc and generally perpendicular to the plane of the disc which is adapted to hold a plurality of filaments extending radially from the mandrel toward the circumferential edge of the disc. A means for engaging each filament at a point of engagement along the circumferential edge of the disc at a plurality of discrete radial locations a distance d from immediately adjacent points of engagement and a means for capturing a subset of the filaments are also provided. The means for capturing a subset of the filaments is positioned circumferential around the edge of the disc and extends toward the circumferential edge of the disc. A means is further provided for moving the captured subset of filaments away from the circumferential edge of the disc in a generally radial direction. A means for rotating the disc and captured subset of filaments relative to one another is also provided.
In some embodiments, the means for rotating the disc and captured subset of filaments relative to one another comprises a means for rotating the disc a discrete distance. Alternatively, the means for rotating the disc and captured subset of filaments relative to one another may comprise a means for rotating the captured filaments a discrete distance.
In some embodiments the means for capturing a subset of filaments may comprise a plurality of hooks.
Also described are methods for forming a tubular braid. The methods comprise steps of providing a braiding mechanism comprising a disc defining a plane and a circumferential edge, a mandrel extending from a center of the disc and generally perpendicular to the plane of the disc, and a plurality of actuators positioned circumferentially around the edge of the disc. A plurality of filaments are a loaded on the mandrel such that each filament extends radially toward the circumferential edge of the disc and each filament contacts the disc at a point of engagement on the circumferential edge, which is spaced apart a discrete distance from adjacent points of engagement. A first subset of the plurality of filaments is engaged by the actuators and the pluralities of actuators are operated to move the engaged filaments in a generally radial direction to a position beyond the circumferential edge of the disc. The disc is then rotated a first direction by a circumferential distance, thereby rotating a second subset of filaments a discrete distance and crossing the filaments of the first subset over the filaments of the second subset. The actuators are operated again to move the first subset of filaments to a radial position on the circumferential edge of the disc, wherein each filament in the first subset is released to engage the circumferential edge of the disc at a circumferential distance from its previous point of engagement.
In some embodiments, the second subset of filaments is engaged and the pluralities of actuators are operated to move the engaged filaments in a generally radial direction to a position beyond the circumferential edge of the disc. The disc is then rotated in a second, opposite direction by a circumferential distance, thereby rotating the first subset of filaments a discrete distance and crossing the filaments of the second subset over the filaments of the first subset. The actuators are operated a second time to move the second subset of filaments to a radial position on the circumferential edge of the disc, wherein each filament in the second subset engages the circumferential edge of the disc at a circumferential distance from its previous point of engagement.
In some embodiments, these steps may be repeated. Alternatively, a third subset of the plurality of filaments may be engaged and the plurality of actuators is operated to move the engaged filaments in a generally radial direction to a position beyond the circumferential edge of the disc. The disc may then be rotated in a first direction by a circumferential distance, thereby rotating a fourth subset of filaments a discrete distance and crossing the filaments of the third subset over the filaments of the fourth subset. The actuators are operated a second time to move the third subset of filaments to a radial position on the circumferential edge of the disc and the fourth set of filaments is then engaged. The actuators are operated again to move the engaged filaments in a generally radial direction to a position beyond the circumferential edge of the disc and the disc is then rotated in a second, opposite direction by a circumferential distance, thereby rotating the third subset of filaments a discrete distance and crossing the filaments of the fourth subset over the filaments of the third subset. The actuators are operated again to move the fourth subset of filaments to a radial position on the circumferential edge of the disc.
Some embodiments of a method for forming a tubular braid include providing a braiding mechanism comprising a disc defining a plane and a circumferential edge having a plurality of notches, each notch separated from the next adjacent notch by distance d, a mandrel extending from a center of the disc and generally perpendicular to the plane of the disc, and a plurality of catch mechanisms positioned circumferentially around the edge of the disc, each catch mechanism extending toward the circumferential edge of the disc. The mandrel of the braiding mechanism is loaded with a plurality of filaments extending toward the circumferential edge of the disc wherein each filament rests within a different notch on the circumferential edge. To make a one over one under braid, the pluralities of catch mechanisms are operated to engage every other filament and pull the engaged filaments away from the circumferential edge of the disc in a generally radial direction, thereby emptying every other notch. The disc is then rotated in a first direction by a circumferential distance and the plurality of catch mechanisms are operated to release each engaged filament radially toward the circumferential edge of the disc, wherein each filament is placed in an empty notch located a circumferential distance 2d from the notch formerly occupied. To make other braid patterns, such as two over, one under, the plurality of catch mechanisms are operated to engage every third or higher filament, as will be understood by those skilled in the art.
In some embodiments, the disc is rotated by a circumferential distance and the plurality of catch mechanisms are then operated to engage every other filament and pull the engaged filaments in a generally radial direction to a position beyond the circumferential edge of the disc. The disc is then rotated in a second, opposite direction by a circumferential distance; and the plurality of catch mechanisms are operated to release each engaged filament radially toward the circumferential edge of the disc, wherein each filament is placed in an empty notch located a circumferential distance from the notch formerly occupied. In some embodiments, the disc is rotated by a circumferential distance 2d in the first direction. In some embodiment, the disc may further be rotated by a circumferential distance 2d in the second direction.
Some embodiments of a tubular braid include a braid made by a process including temporarily affixing a plurality of filaments on a distal end of a mandrel extending perpendicularly from the center of a disc such that each filament extends radially from the mandrel towards the circumferential edge of the disc and engage the circumferential edge of the disc at independent points of engagement separated by a distance d from adjacent points of engagement. The first subset of filaments is engaged and pluralities of actuators are operated to move the engaged filaments in a generally radial direction to a radial position beyond the circumferential edge of the disc. The disc is rotated in a first direction by a circumferential distance, thereby rotating a second subset of filaments still engaging disc a discrete distance and crossing the filaments of the first subset over the filaments of the second subset. The plurality of actuators is operated to move the first subset of filaments to a radial position on the circumferential edge of the disc, which is a circumferential distance from its previous point of engagement. The second subset of filaments is engaged and the actuators are operated to move the engaged filaments in a generally radial direction to a radial position beyond the circumferential edge of the disc. The disc is rotated disc in a second, opposite direction by a circumferential distance, thereby rotating the first subset of filaments a discrete distance and crossing the filaments of the second subset over the filaments of the first subset. The actuators are then operated to move the second subset of filaments to a radial position on the circumferential edge of the disc, wherein each filament in the second subset engages the circumferential edge of the disc at a circumferential distance from its previous point of engagement.
In some embodiments the braid formed has a one-over, one-under (diamond) braid pattern. Alternatively, the braid formed may have a one-over, three-under braid pattern. Alternatively, the braid formed may have a two-over, two-under braid pattern.
Discussed herein are devices and methods for creating a tubular braid from a plurality of filaments. Because the braiding machine individually engages a subset of the filaments and moves the engaged filaments relative to the unengaged filaments in discrete steps to interweave the filaments, it does not create the large tension spikes common to the continuous motion braiding machines. Thus, the invention is particularly useful for making braided tubes of ultra fine filaments, in the order of ½ mil-5 mil, for example, for use in vascular implants, such as embolization devices, stents, filters, grafts, and diverters for implantation in the human body. It will be appreciated, however, that the invention could also be advantageously be used for making braids for other applications and with other sized filaments.
The ability to individually engage a subset of filaments and move the filaments in discrete steps also allows for both flexibility in the loading of the machine and in the braid pattern created. The machine can be programmed to accept multiple loading configurations and create multiple braid patterns by alternating the subset of filaments engaged and/or the distance moved in each discrete step. For example while a one over-one under diamond braid pattern is shown and discussed, other braid or weave patterns, such as a two over-two under, two over-one under, one over-three under may also be used by varying the filaments engaged and the distances moved in each step. Likewise, by adjusting filaments engaged and the distances moved in each step, the machine call operate when loaded in a variety of configurations, i.e. fully loaded or partially loaded, to create tubular braids with differing numbers of filaments.
It also may be desirable to vary the size of the plurality of filaments. For example, in some uses for implantation in the human body discussed above, the need for stiffness and strength must be balanced with the need to collapse the braid into a small delivery size. Adding several larger diameter filaments to the braid greatly increases the radial strength without much increase in the collapsed diameter of the braid. The braiding machine described herein is able to accommodate different sizes of wires and thereby produce implants that optimize stiffness and strength as well as porosity and collapsed diameter.
As shown in
The filaments may be looped over mandrel 10 such that the loop catches on the notch formed at the junction of tip 12 and mandrel 10. For example, as shown in
In some embodiments, the mandrel may be loaded with about 10 to 1500 filaments, alternatively about 10 to 1000 filaments, alternatively about 10 to 500 filaments, alternatively about 18 to 288 filaments, alternatively 104, 144, 288, 360, or 800 filaments. In the event that a wire is draped over the mandrel, as described above and illustrated in
Circular disc 20 defines a plane and a circumferential edge 22. A motor, such as a stepper motor, is attached to disc 20 to rotate the disc in discrete steps. The motor and control system may be housed in a cylindrical drum 60 connected to the bottom side of the disc. In some embodiments, drum 60 may have a diameter about equal to disc 20 such that the longitudinal side of the of drum 60 can act as a physical mechanism to stabilize the filaments extending over the edge of the disc For example, in some embodiments, the side of the drum may be made of an energy absorbing, slightly textured, grooved surface, or surface having projections such that when the filaments extend over the edge of the disc, they will come to rest against the side of drum 60 such that the filaments are substantially vertical and not tangled.
A plurality of catch mechanisms 30 (see
The number of catch mechanisms determines the maximum number of filaments that can loaded on the braiding machine, and therefore, the maximum number of filaments in a braid made thereon. The number of catch mechanisms will generally be ½ the maximum number of filaments. Each catch mechanism may handle two threads (or more); therefore, for example, a braiding machine having 144 catch mechanisms extending circumferentially around disc 20 can be loaded with a maximum of 288 filaments. Because each of catch mechanism 30 is individually activated, however, the machine can also be operated in a partially loaded configuration loaded with any even number of filaments to create a braid having a range of filaments.
Each catch mechanisms 30 is connected to an actuator 40 that controls the movement of the catch mechanism toward and away from circumferential edge 22 of disc 20 to alternately engage and release filaments 5 one at a time. Actuator 40 may be any type of linear actuator known in the art such as electrical, electromechanical, mechanical, hydraulic, or pneumatic actuators, or arty other actuators known in the art that are capable of moving catch mechanism 30, and an engaged filament 5, a set distance both away from and toward disc 20. Catch mechanism 30 and actuators 40 are positioned around the circumference of the disc such that the motion of the actuators causes the catch mechanisms to be moved in a generally radial direction away from and toward circumferential edge 22 of disc 20. Catch mechanisms 30 are further positioned such that catch mechanisms 30 engage the selected filament 5 as it extends over the circumferential edge of disc 20. For example, in some embodiments, the catch mechanisms are located in a horizontal plane and slightly beneath the plane defined by disc 20. Alternatively, the catch mechanisms may be angled such that when they are moved toward the disc, they will intercept the filament at a point below the plane defined by disc 20. As shown in
In use, as shown in
To engage a first set of filaments 5a,c,e,g, and i, as shown in
As shown in
Next, as shown in
Next, as shown in
As shown in
As shown in
Alternatively, a fixed former ring 75 having a predetermined and non-adjustable bitter diameter that closely matches the outer diameter of mandrel 10 can be used to pull braid 55 tightly against mandrel 10. In some embodiments, as shown in
As illustrated in
The motion of each individual catch mechanism 30a-d will not be precisely radial with respect to disc 20 however, it will have a radial component that is substantially radial. Because the angle with respect to radial that the catch mechanism is pulled increases with increasing circumferential distance from the axis of the linear motion, the number of catch mechanisms that can be carried by rake 32 is limited. Ideally, the upper limit for the angle of motion with respect to radial for each the catch mechanisms is about 45°, alternatively about 40°, alternatively about 35°, alternatively about 30°, alternatively about 25°, alternatively about 20°, alternatively about 15°, alternatively about 10°, alternatively about 5°, in order to maintain consistency in the relative circumferential distances move by the engaged filaments. For example, each rake may cover 90°of the 360° circumference when operating at an angle of 45° with respect to radial. In some embodiments, rake 32 may carry 1-8 catch mechanisms, alternatively 1-5 catch mechanisms, alternatively 1-4 catch mechanisms and still maintain an acceptable deviation from radial motion for all of the catch mechanisms carried thereon.
In addition, as shown in
The filaments may also be tensioned with a plurality of individual tensioning elements 6a-x, such as a weight, or any other tensioning element known in the art for applying between about 2-20 grains of weight to each of the individual filaments. Tensioning elements 6a-x are sized to fit in the plurality of grooves 66 on drum 60. For example, each tensioning element may comprise an elongate cylindrical weight as illustrated in
In another alterative embodiment, as illustrated in
As shown in
Other alternatives for the configuration of the horizontally oriented catch mechanisms discussed above are shown in more detail in
It is further envisioned that a braiding machine according to the present invention could use a combination of the single and multiple catch mechanism embodiments arrayed around the circular disc to achieve the optimum balance between efficiency of the machine and flexibility in loading configurations and braiding patterns possible. As discussed above, the braiding machine can be operated to accept multiple loading configurations and create multiple braid patterns by alternating the subset of filaments engaged and/or the distance moved in each discrete step. Turning to
In
In
Here, at step 900, the actuators are actuated to move all of the hooks toward the circular disc in generally radial direction. At step 902, the disc is rotated in a first direction to engage alternating (even) wires. At step 904, the actuators are actuated to move all books away from the circular disk, thereby removing the engaged filaments from contact with the circular disc. At step 906, the disc is rotated in the first direction by circumferential distance 2d to cross each of the unengaged filaments under an adjacent engaged filament. At step 908 the actuators for the rakes of multiple hooks are actuated to move all of the multiple-hook rakes toward the circular disk until the wires engage the disc and are thus released from the multiple-hook rakes. At step 912, the actuators for the rakes of multiple hooks are actuated to move all multiple-hook rakes away from the circular disk. At step 914, the disc is rotated in the first direction by a circumferential distance xd (x depends on number of wires loaded per section). At step 916, the actuators are actuated to move all hooks toward the circular disc until the wires engage the disc and are thus released. At step 918, the disc is rotated to engage alternating (odd) wires in all of the hooks. At step 920, the actuators are actuated to move all hooks away from the circular disk, thereby removing the engaged (odd) filaments from the circular disc. At step 922, the disc is rotated by circumferential distance 2d in the second, opposite direction to cross each of the unengaged (even) filaments under an adjacent engaged (Odd) filament. At step 924, the actuators for the rakes of multiple hooks are actuated to move all multiple-hook rakes toward the circular disk until the wires engage the disc and are thus released. At step 928, the actuators for the rakes of multiple hooks are actuated to move all multiple-hook rakes away from circular disk. At step 930, the disc is rotated by a circumferential distance xd in the second, opposite direction (x depends on number of wires loaded per section). At step 932, the actuators are actuated to move all hooks toward the circular disc until the wires engage the disc and are thus released. At step 934, the disc is rotated to engage alternating (even) wires in all of the hooks. These instructions are then repeated from step 904 to create a tubular brad on the mandrel.
Although the foregoing invention has, for the purposes of clarity and understanding, been described in some detail by way of illustration and example, it will be obvious that certain changes and modifications may be practiced which will still fall within the scope of the appended claims.
This is a continuation of U.S. application Ser. No. 14/330,990, filed Jul. 14, 2014, which is a continuation of U.S. application Ser. No. 13/871,372, filed Apr. 26, 2013, now issued as U.S. Pat. No. 8,820,207, which is a continuation of U.S. application Ser. No. 13/570,499, filed Aug. 9, 2012, now issued as U.S. Pat. No. 8,430,012, which is a continuation of U.S. application Ser. No. 13/275,264, filed Oct. 17, 2001, now U.S. Pat. No. 8,261,648. The disclosures of all of the above-referenced applications are incorporated herein by reference in their entirety.
Number | Date | Country | |
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Parent | 14330990 | Jul 2014 | US |
Child | 15463866 | US | |
Parent | 13871372 | Apr 2013 | US |
Child | 14330990 | US | |
Parent | 13570499 | Aug 2012 | US |
Child | 13871372 | US | |
Parent | 13275264 | Oct 2011 | US |
Child | 13570499 | US |