Abstract:
The present invention is an apparatus for inserting yarns into a reinforcement material along their longitudinal path. The apparatus for moving yarn and for constraining yarn movement, such as yarn brakes, are each actuated at the appropriate time. The yarn is prevented from buckling by a hollow member of a diameter only slightly greater than the yarn, when the yarn is pushed on. The reinforcement material may be woven or non-woven fabrics, cellular foams, or combinations that may include fabrics, foams or air gaps. “Yarn” in this case is taken to include any textile yarn, monofilament, coated yarns, and the like.

Description:
This application claims the benefit of Provisional No. 60/108,729 filed Nov. 17, 1998. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to the field of composite materials, and apparatuses which are used to make them. More particularly, the present invention describes an apparatus for inserting yarns in a substantially longitudinal direction. 
     BACKGROUND OF THE INVENTION 
     The use of reinforced composite materials to produce structural components is now widespread, particularly in applications where their desirable properties are sought. Depending on the material, those properties include light weight, strength, toughness, thermal resistance, self-support and adaptability in terms of being formed and shaped. Such components are used, for example, in aeronautical, aerospace, satellite, battery, recreational vehicles (as in racing boats and automobiles), and other applications. 
     Often, the desired property in a material used to make reinforcement preforms is high strength. However, a typical characteristic of materials which exhibit that property is that their highest strength is in the direction of the long axes of the constituent fibers or filaments. For this reason, it is desirable to fabricate such reinforcement preforms to so orient the reinforcement preform constituent materials so that their long axes are substantially in the same direction as will be the forces to which the finished components will be subjected. Since those forces may be multi-directional, in some applications the reinforcement material may be oriented multi-directionally, typically in a lamination of two or more plies, to render the strength properties of the finished component operable in more than one direction, even to the point of being quasi-isotropic. By this means, such forces may be caused to be borne primarily by fibers whose long axes are oriented in the direction those forces, thus enabling the strengthening constituents of the composite structures to present their highest load-bearing capabilities to them. 
     Frequently, it is desired to produce components in configurations that are other than such simple geometric shapes as (per se) plates, sheets, rectangular or square solids, etc. A way to do this is to combine such basic geometric shapes into the desired more complex forms. One such typical combination is made by joining reinforcement preforms made as described above at an angle (typically a right-angle) with respect to each other. Such angular arrangements of joined reinforcement preforms create a desired shape which include one or more end walls or “T” intersections between the preforms. This arrangement may strengthen the resulting combination of reinforcement preforms and the composite structure that is produced against deflection or failure upon being exposed to exterior forces, such as pressure or tension. In any case, a related consideration is to make each juncture between the constituent components as strong as possible so forces cannot pull the composite article apart. Otherwise, given the desired very high strength of the reinforcement preform constituents per se, weakness of the juncture compared to that of each of the combined elements per se becomes the weak link in the structure. 
     An example of this type of intersecting configuration is where one of two constituents is an elongated, flat, planar rib that is oriented substantially at a right angle to and across a mid-span location of the other constituents, which is a planar sheet. In this structural arrangement, it is desirable to inhibit or prevent the planar sheet from deflecting objectionably or failing as pressure is applied in the direction of the width dimension of the reinforcing rib. Also, it is desirable to provide a juncture between intersecting elements (such as planar sheets per se, sheets and strips or other shapes, etc.) which will not fail when forces are applied to one of the intersecting elements in directions away from the other element which it intersects. 
     Various proposals have been made in the past for making such junctures. The forming and curing of a first panel element and a second angled stiffening element has been proposed, with the latter having a single panel contact surface, or otherwise bifurcated at one end to form two divergent, co-planar panel contact surfaces. The two components are then joined by adhesively bonding the panel contact surface(s) of the stiffening element to a contact surface of the other component using thermosetting adhesive or other adhesive material. However, when tension is applied to the cured panel or the skin of the composite structure, loads at unacceptably low values result in peel forces which separate the stiffening element from the panel at their interface since the effective strength of the join is that of the reinforcement material and not of the adhesive. 
     To use metal bolts or rivets at the interface of such components is also unacceptable because such additions at least partially destroy and weaken the composite structures themselves, add weight, and introduce differences in the coefficient of thermal expansion as between such elements and the surrounding material. 
     Other approaches to solving this problem have been based on the concept of introducing high strength fibers across the join area through the use of such methods as stitching one of the components to the other and relying upon the stitching thread to introduce such strengthening fibers into and across the juncture site. One such approach is shown in U.S. Pat. No. 4,331,495 and its divisional counterpart, U.S. Pat. No. 4,256,790. These patents disclose junctures between a first and second composite panels made from adhesively bonded fiber plies. The first panel is bifurcated at one end to form two divergent, co-planar panel contact surfaces, each joined to the second panel by stitches of uncured flexible composite thread through both panels. The panels and thread have then been “co-cured”, i.e., cured simultaneously. This proposal is inadequate as evidenced by subsequent efforts to cope effectively with the problem of join strength. 
     U.S. Pat. No. 5,429,853 proposes ajoin between reinforced composite components that are in the form of a panel and of strengthening rib. One of the components is in the form of an elongated strip which is angled linearly to form a panel contacting bearing flange that is continuous with the rest of the rib which forms a stiffening flange. As disclosed, two such ribs may be joined to each other with their stiffening flanges back to back. The effect of this is effectively to create a bifurcated element having the panel contacting surfaces across the top of the “T” so formed. The bearing flange(s) of the stiffening rib are placed in contacting juxtaposition with a the surface of the panel, and the two elements (i.e., the rib and the panel) are then joined by a fibrous “filament” or thread which is inserted vertically through the panel and into the reinforcing member, with some of the filament extending into and in line with the main body of the “stiffening flange” i.e., the portion of the stiffening rib which is vertical to the plane of the panel element. The asserted effect of this is to have some of the fibers that have been introduced by the filament extend from the panel element into the stiffening flange portion of the stiffening rib. While perhaps efficacious for certain purposes, such prior art constructions still do not exhibit the desired amount of strength against failure of such joins with consequent separation of the constituent reinforced elements from each other. 
     SUMMARY OF THE INVENTION 
     The objective of the present invention is to provide an apparatus for inserting yams into a reinforcement material such as woven or non-woven fabrics, cellular foams or combinations that may include fabrics, foams or air gaps. “Yarn” in this case is taken to include any textile yam, monofilaments, coated yams, and the like. 
     The concept behind the apparatus is to control the motion of the yam by using means for moving yarn and means for constraining yam movement, such as yam brakes, each actuated at the appropriate time, plus a means of preventing the yarn from buckling, such as a hollow member of a diameter only slightly greater than the yarn, when the yarn is pushed on. 
     The present invention is an apparatus for longitudinally inserting yams into a reinforcement material wherein the invention has a housing provided with a first end for receiving yam and a second end for passing yarn, the first and second ends being in communication with means for maintaining yarn in a longitudinal path, means for moving yarn in a longitudinal path, means for actuating yarn movement, means for constraining yarn against movement, and means for boring a longitudinal path in a reinforcement material. The means for maintaining yarn in a longitudinal path may be at least one hollow member, such as a cylinder, extending longitudinally through the housing. Preferably, it is comprised of first and second hollow members in a telescoping arrangement, the first of which is stationary within the housing and the second of which is movable longitudinally. In one embodiment, the means for maintaining yarn in a longitudinal path is movable between an initial position and a second position corresponding to where yarn has been inserted into a reinforcement material, and is provided with means for engaging yarn, the engaging means being in engagement with the yarn during travel between the initial position and the second position. During return of the means for maintaining yarn in a longitudinal path from the second position to the initial position, means for constraining yarn against movement engage the yarn and keep it in the inserted position. The means for moving yarn in a longitudinal path and the means for constraining yarn against movement can be actuated pneumatically, electronically, mechanically, or electro-mechanically. The means for actuating yarn movement could be a piston coupled to the means for maintaining the yarn in a longitudinal path. In a preferred embodiment, the piston, the means for moving yarn in a longitudinal path, and the means for constraining yarn against movement are actuated pneumatically. The means for boring a longitudinal path in a reinforcement material is a hypodermic-type sewing needle provided with an opening for receiving the yarn. The hypodermic needle has a hollowed out interior and an opening at its tip, through which the yarn is fed. Yarn is carried with this needle as it moves into the reinforcement material in the direction of insertion, and remains in place (due to the aforenoted action of the means for constraining yarn against movement) as the needle is retracted after insertion. 
     It should be understood that the present invention permits the skilled artisan to fully realize the benefits of high performance materials which exhibit their properties isotropically. This apparatus could be used for inserting yarns, rovings, pre-impregnated yarns, monofilaments, etc, into such materials as plies of fabrics, non-woven goods such as felts, three dimensional woven preforms, foams, plies of pre-impregnated fabrics such as used in advanced composites. Some of the ways in which the present invention could be used include 
     Inserting yarns into carbon fiber preforms in order to join sections of preforms of yarns prior to injecting a matrix material such as epoxy; 
     Inserting fragile yarns such as NEXTEL® ceramic yarns without overwrapping them with tough yarns such as polyesters. This will save on both pre- and post-processing costs. It will also allow very small needles to be used and not require that a yarn be dragged in beside the needle. This will reduce substantially the damage caused to the fabrics by the insertion process; 
     Inserting sacrificial yarns through carbon fabrics that become carbon/epoxy wing skins; 
     Adding through thickness reinforcement to composite panels in order to improve the processing stresses, the interlaminar properties and the resistance to drainage propagation; 
     Inserting a second kind of yarn into a reinforcement material that is comprised of a material different from the first kind of yarn. For example, the second yarn may exhibit a higher thermal conductivity than the reinforcement material, thereby improving the efficiency at which heat is removed form the reinforcement material; and 
     Sewing of complex shapes without access to the backside of the structure—such as in small tubes or intricate shapes. 
     Prior art apparatuses are more limited in their applications. A system with the above features and the ability to invoke these features as required will cover virtually all applications envisioned for the composite materials field. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the preferred embodiment of the present invention. 
     FIG. 2 is a perspective view of alternative yarn brake arrangement. 
     FIG. 3 is a perspective view of another alternative yarn brake arrangement. 
     FIG. 4 is a perspective view of yet another alternative yarn brake arrangement. 
     FIG. 5 is a perspective view of another embodiment of the present invention. 
     FIG. 6 is a perspective view of an aspect of the FIG. 5 embodiment. 
     FIG. 7 is a top plan view of an aspect of the FIG. 5 embodiment. 
     FIG. 8 is a is a top plan view of an aspect of the FIG. 5 embodiment. 
     FIG. 9 is an exploded view of an aspect of the FIG. 5 embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Yarn insertion mechanism  10  is provided with housing  12  which may be cylindrical in shape. Housing  12  has first end  14  and second end  16 . Yarn Y is fed from a spool, a mandrel or other known means for continuously feeding yarn (not shown) and enters the first end  14  through passageway  18  having the shape of an inverted cone. Yarn Y first passes through the relatively wide portion  18   a  of the passageway and then passes through an aperture in its tip  18   b . Tip  18   b  is in communication with a first hollow member  20  having walls defining a hollow interior. The inside diameter of member  20  should only be slightly greater than the diameter of the yarn Y, but should permit a yarn to move through it. 
     At the second end  16  of the housing  12 , second hollow member  22  extends from within the housing to  12  to beyond the second end  16 . Second hollow member  22  passes through sealing member  24 . The first hollow member  20  is placed inside the second hollow member  22  in a telescoping arrangement. Its inside diameter is greater than the outside diameter of the first hollow member  20 . Yarn Y extends through the second hollow member  22  to the distal end  22   a  thereof. At distal end  22   a , the yarn is threaded through the opening of a needle  26 . The needle resides within the distal end  22   a . A screw or chuck  28  secures the needle within the distal end  22   a.    
     As noted, the lower end of the first hollow member  20  is located within the second hollow member  22  in a telescoping arrangement within the housing  12 . In this embodiment, the first hollow member  20  is fixed in place by fittings  30  and  32 , which form a secure fit between the walls of the housing  12  and first hollow member  20 . On the other hand, second hollow member  22  can slidably move along its longitudinal axis and is mounted over the lower end of first hollow member  20 . Second hollow member  22  slides through sealing member  24 , its distal end  22   a  and needle  26  movable away from the housing  10 . When yarn Y is threaded through the hollow members and through the opening, movement of the second hollow member will move yarn Y away form the housing  10 . The second hollow member  22  is fitted within piston  34 , which is a disk corresponding to the shape of the housing  12  and which is in contact with and slides along the interior housing wall. In essence, the second hollow member  22  is a piston rod that is slidably mounted within the housing  12 , and can drive needle  28  and Yarn Y away from the housing into a reinforcement material. 
     The skilled artisan will appreciate that there are several ways in which to actuate the slidable movement of the second hollow member  22 , such as pneumatically, mechanically, electro-mechanically, and electrically. FIG. 1 shows a yarn insertion mechanism that is pneumatically actuated. In this embodiment, the interior of the housing is subdivided into four zones or compartments A, B, C, and D, each of which is sealed off from the other zones. Zone A is sealed off by fittings  30  and  32 . Zone B is sealed off by fitting  33  and piston  34 , and Zone C is sealed off by piston  34  and sealing member  24  located at second end  16 . Zone D is vented to the atmosphere and is sealed by fittings  32  and  33 . Each zone is respectively provided with nozzles  40 ,  42  and  44  through which a pressurized fluid, such as compressed air, can enter the zone, as well as exit the zone, by way of a hose or line (not shown) which is in communication with a pressurized fluid source (not shown). In this embodiment, the second hollow element  22  and yarn Y traveling within it is actuated away from the housing  10  to effect yarn insertion when pressurized fluid is fed to zone B. The second hollow member  22  is actuated upwardly, or in other words in the direction of retraction of the second hollow member, when the pressure in zone C exceeds that in zone B. Ordinarily, this will be effected by releasing the pressurized fluid from zone B and applying pressurized fluid in zone C. 
     In zone B, there is provided a first yarn brake arrangement  46 . Brake pad  48  is fitted within aperture  50  which is located on the second hollow member. Spring  52  extends over aperture  50  and biased against brake pad  48 . A rubber bladder  54  or the like is fitted over the brake pad arrangement  46 . The first yarn brake arrangement  46  is actuated by the build-up of pressurized fluid in zone B. 
     In Zone A, a second yarn brake arrangement  56  is provided. The second yarn brake arrangement is identical to the first yarn brake arrangement, except that brake pad  58  is fitted within an aperture  60  within the stationary first hollow member  20 . The second yarn brake arrangement  56  is actuated by the build-up of pressurized fluid in zone A. 
     The first and second yarn brakes of this embodiment are actuated pneumatically. When a pressurizing fluid enters zones A and B, elevated pressure engages brake pads  48  or  58  against yarn Y, which effects the restraint necessary to either actuate movement of the yarn out of the housing and into the reinforcement, or to prevent upward actuation of the yarn or buckling of the yarn after insertion. This will be explained below. 
     The operation and use of the yarn insertion mechanism will now be described. Yarn Y enters the housing at first end  14  and is threaded through the telescoping arrangement defined by the first and second hollow members  20 ,  22 . Yarn Y is threaded through needle  26 , which is fixed to the distal end  22  of second hollow member  22 . 
     Initially, the fluid pressure in zones A, B and C is insufficient to actuate the components in these zones. Ordinarily, this means that no fluidizing pressure is being applied, and that the pressure is the atmosphere pressure. In this condition, the tension of the springs  52  holds the brake pads  48 ,  58  out of engagement with the yarn, so that the yarn can be threaded. 
     When air pressure is applied in Zone B, first yarn brake arrangement  46  is actuated. Brake pad  48  is pushed against yarn Y by the pressure build-up in the zone. Also, the pressure build-up moves piston  34  downwardly. In turn, this moves the second hollow member  22  and needle  26  away from the housing, towards the reinforcement material and then into the reinforcement material. Yarn Y travels with the second hollow member since the brake pad  48  of first yarn brake arrangement is engaged against the yarn. By positioning the needle above a reinforcement material and actuating the yarn insertion mechanism as described above, the needle bores through the reinforcement material, creating a substantially longitudinal path for the second hollow member and yarn Y. Yarn Y is inserted along this substantially longitudinal path. 
     After insertion of yarn Y, removal of the needle  26  and second hollow member  22  without displacement or buckling of yarn Y is effected as follows. The fluidizing pressure is released from zone B, disengaging first yarn brake arrangement  46  from yarn Y. Simultaneously, fluidizing pressure is applied to zones A and C. The application of fluidizing pressure in zone A actuates the second yarn brake arrangement  56  located in the stationary first hollow member  20  in the manner described with respect to the first yarn brake arrangement. 
     The application of fluidizing pressure in zone C causes piston  34  to move upwardly, moving the second hollow member  22  and the needle  26  out of the reinforcement material and retracting the second hollow member  22  into the housing  12 . The upward movement of the piston  34  is eventually stopped by a piston stop  62  placed above the piston  34  in zone B. While the second hollow member  22 , piston  34 , and needle  26  are retracting, yarn Y is held stationary, since the second yarn brake arrangement  56  located in the stationary first hollow member  20  is engaged against the yarn by the build-up of pressure in zone A. Furthermore, since the inside diameters of the first and second hollow members are only slightly greater than the yarn diameter, the first and second hollow members maintain the yarn in a longitudinal path, preventing yarn buckling. That is, the yarn is constrained and cannot move, maintaining yarn Y in place within the reinforcement material while the second hollow member  22 , piston  34 , and needle  26  are retracted. This is the case even though the opening of the needle is sliding over the yarn during retraction. 
     In the aforedescribed embodiment, the yarn brake arrangements are pneumatically actuated, but they need not be so. For instance, the yam brake arrangements may be actuated pneumatically, mechanically, electro-mechanically, and electrically. If actuation is not effected by pneumatic means, it may not be necessary to compartmentalize the housing into sealed zones. 
     An alternative arrangement for a yarn brake arrangement is shown in FIG.  3 . Yarn brake arrangement  64  is provided with a fixed stop or pad  66 . Rotating arm or cam  68  is actuated to pivot into yarn Y and fix it in place against pad  66 . This is an example of a mechanical yarn brake arrangement that eliminates the need for the components of a pneumatic system. 
     In FIGS. 2 and 4, two other pneumatically actuated yarn brake arrangement  70  and  80  are depicted. In FIG. 2, when air actuated cylinder  72  is pressurized, brake pad  76  affixed to rod  74  is actuated against yarn Y, braking it against fixed pad  78 . This arrangement is akin to a direct squeeze upon the brake pad. Releasing pressure from air cylinder  72  releases brake pad  76  from yarn Y. 
     In FIG. 4, air cylinder  82  is actuated against cam  84  arranged on pivot  86 . Actuation causes the cam  84  to pivot, thereby displacing brake pad  86  against yarn Y. Yarn Y is fixed in place between brake pad  88  and fixed pad  90 . This is akin to an indirect squeeze. In a variation of this embodiment, the rotating cam  84  can pivot directly into the yarn Y, thereby eliminating the need for a brake pad. 
     Another embodiment of the invention is depicted in FIGS. 5 to  9 . In FIG. 5, a yarn insertion mechanism  100  is shown having a driver component  102  and yarn carrier mechanism  104  fitted within a housing  101 . 
     During operation, driver component  102  is mounted within housing  101 , remaining stationary. Driver component  102  drives the yarn carrier mechanism  104  to effect yarn insertion. The yarn carrier mechanism  104  has a lower portion  106  and upper portion  108  that fit together in a complimentary arrangement. A hypodermic needle  110  is affixed to the distal end of the lower portion  106 . Yarn Y is threaded through driver component  102 , yarn carrier mechanism  104 , and hypodermic needle  110 . This is the general arrangement; the specific arrangement is described with particularity below. 
     Still referring to FIG. 5, driver component  102  is provided on its rear face  112  with a tubular inlet  114  for receiving pressurized fluid from a pressurized fluid source (not shown). Tubular inlet  114  is in communication with the driver component  126  by way of conduit  116  which enters the body  118 . Inside the body, there is provided a tunnel (not shown) that serves as a flow path for the pressurized fluid that enters the body. Driver element  126  extends out of the tunnel for the pressurized fluid, and is actuable in an outward direction in response to the application of pressurized fluid. When actuated, the driver element  126  moves out of the conduit  116  in the direction of the yarn carrier mechanism  104 . When pressure actuated, driver element  126  is attached the upper portion  108  of the yarn carrier mechanism  104  and moves it forward with the driver element  126 . 
     Yarn enters the body  118  of driver component  102  through entranceway  120  provided on the rear face  112 , and passes through the driver component  102  via a tunnel  122 . Entranceway  120  is depicted as a tubular extension off of the driver component  102 . Yarn passes through tunnel  122  and tube  123  on its way through tube yarn carrier mechanism  104 . 
     FIG. 6 shows the front face of the driver component  102 , or in other words, the side which faces the yarn carrier mechanism  104 . The driver element  126  extends out of the tunnel for the pressurized fluid. When pressurized fluid is supplied to the driver component  102 , driver component is actuated, moving out of the driver component in response to pressurization. 
     The front face  124  is further provided with first and second tunnels  128  for receiving guide members  136  that extend from the yarn carrier mechanism  104 . The front face is also provided with yarn tube  130  which is in communication with tunnel  122 . Yarn tube  130  extends from the front face  124 , and the yarn passes through it on its way to the yarn carrier mechanism  104 . 
     Yarn carrier mechanism  104  is constructed of upper portion  108  and lower portion  106 . The lower portion  106  is a solid body construction provided with a slotted or grooved profile on its upper face. The slotted profile complements and receives the shape of the upper portion  108 . This arrangement can be seen in FIG. 7, where it is shown that upper portion  108 , having a longitudinal body portion  132  and wings  134 , is cross-shaped, and lower portion  106  is slotted in a complementary way in order to receive the upper portion  108 . 
     As shown in FIG. 5, driver  126  extends from the driver component  102  and is affixed to the rear side of yarn carrier mechanism  104 . Driver  126  moves outwardly due to pressurization, pushing upper portion  108  of the yarn carrier mechanism  104  in the direction of yarn insertion. As the wings  134  of upper portion  108  engage the inner walls of the profiled lower portion  106 , the lower portion  106  is driven outwardly as well, and at this time, the entire yarn carrier mechanism  104  moves in the direction of yarn insertion. Driver  126  is a means for actuating the means for moving yarn. 
     Lower portion  106  of yarn carrier mechanism  104  is further provided with extending guide members  136  which extend from the rear side of the lower portion  106 . These guide members are located and dimensioned to fit within the tunnels  128  on the front side  124  of the driver component  102 . Lower portion  106  is further provided with a yarn tube  131  which receives, in a telescoping arrangement, the yarn tube  130  extending from the front face of  114  of the stationary driver component  102 . During the movements associated with insertion and retraction, the guide members  136  slide in and out of tunnels  128  while remaining within them. Likewise, the yarn travels through the tunnel in the stationary driver component  102 , through yarn tube  130 , through yarn tubes  131  and tunnel  156  in the lower portion  106  of the yarn carrier mechanism  104  and then through the hypodermic needle  110 . Yarn tube  130  extending from the driver component and yarn tube  131  extending from the yarn carrier mechanism  104  are in a telescoping relationship. It should be readily understood that the tunnels in the stationary driver component  102 , the yarn tube  131  and tunnel  156  in the lower portion  106  of the yarn carrier mechanism  104 , and the yarn tube  130  have a diameter only slightly greater than the diameter of the yarn and constitute a means for maintaining yarn in a longitudinal path. 
     FIG. 8 is a top plan view of the lower portion  106  yarn carrier mechanism  104 , with the upper portion  108  removed, revealing the yarn brake  138 . FIG. 9 shows an exploded view of a yarn carrier mechanism  104 , more clearly showing the interrelationship of the upper portion  108  and lower portions  106 , and yarn brake  138 . Upper portion is provided with a lower surface  140  that is planar for a portion  142  of its length then has a triangular cut-out portion formed by an angled wall portion  145  that is part of groove  144 , which is provided with a hook  146  at the wall opposite the angled wall portion  145  of the triangular cut-out portion. 
     As shown in FIG. 9, yarn brake  138  is constituted of a head  148  and pin  150 . Pin  150  extends through aperture  152  into yarn tube  156 , just above yarn Y. Head  148  has an angled surface  149  that is complementary to the surface of the angled wall portion  145  of the groove  144 . As upper portion  108  of the yarn carrier mechanism  104  slides forward in lower portion  106  in response to being pushed by the driver member  126  of the stationary driver component  102 , the angled wall portion  145  of the groove  144  engages the head  148 , depressing it, moving the pin  150  downwardly through the aperture  152  into physical engagement with the yarn. 
     Also, while the upper portion  108  is sliding forward in lower portion  106  of the yarn carrier mechanism  104 , the wings  134  of upper portion  108  engage the inner walls of the profiled lower portion  106 , driving lower portion  106  outwardly in the direction of yarn insertion. This action occurs simultaneous to, or approximately simultaneous to, the aforedescribed action which effects the depressing of the yarn brake  138  and engagement of yarn Y. The yarn Y moves forward with the yarn carrier mechanism  104 , since in this arrangement the pin  150  is in physical engagement with the yarn, that is impinging the yarn against the interior of yarn tube  156 . Yarn carrier mechanism is a means for moving yarn in a longitudinal path. By positioning the needle  110  above a reinforcement material and actuating the yarn insertion mechanism as described above, the needle bores through the reinforcement material, creating a substantially longitudinal path for the needle  110  and yarn Y. Yarn Y is inserted along this substantially longitudinal path. 
     After insertion of yarn Y, removal of the needle  110  without displacement or buckling of yarn Y is effected as follows. The fluidizing pressure is released from inlet  114 , which deactivates the driver element  126 . A spring located within the body  118  of the driver component  102  biases the driver element  126  towards the retracted position. Thus, when the fluidizing pressure is released, the driver element  126  retracts, pulling the yarn carrier mechanism  104  with it. Specifically, as driver element  126  retracts, it pulls upper portion  108  of yarn carrier mechanism  104  and retracts it. As upper portion  108  retracts, hook  146  on head  148  pulls pin  150  away from the yarn and out of engagement with it in order to insure that the yarn Y is not removed as the mechanism retracts. Further, as upper portion  108  retracts, the wings  134  of upper portion  108  engage the inner walls of the profiled lower portion  106 , driving lower portion  106  in the direction of retraction, effecting the retraction movement of the yarn carrier mechanism  104 . 
     At the yarn entranceway  120  of the stationary driver component  102  a yarn brake mechanism  121  is provided in order to keep the yarn from being removed from its inserted position within the reinforcement material while the device is retracted. The yarn brake mechanism is a constrictor which prevents the yarn from traveling our of the tube during retraction. In other words, it is a means for constraining yarn against movement. The constrictor may be a portion of the interior diameter of the yarn entranceway which has a diameter that is the same as, or slightly less than the yarn diameter. The constrictor applies a drag force to the yarn which prevents it from traveling upward with the mechanism as the yarn carrier mechanism is retracted from the insertion position.