OVERWRAP TAPE END-EFFECTOR FOR FIBER PLACEMENT/WINDING MACHINES

Abstract: A tape delivery end-effector apparatus (10) is, in an exemplary embodiment, a multiple-channel system for applying materials in tape form to a tooling mandrel. The end-effector apparatus is mounted on a multi-axis fiber placement machine and uses the machine's computer controlled guidance system. A preset constant tension is independently applied to each tape (30) unspooled from spool holders (34) by a separate servo motor (50), servo amplifier and feedback transducer (120) for each spool holder. The transducer continuously measures the tape spool diameter. Two sets of rollers (44) guide the tapes to the mandrel.

Description: OVERWRAP TAPE END-EFFECTOR FOR FIBER PLACEMENT/WINDING MACHINES TECHNICAL FIELD This invention relates generally to the fabrication of composite structures. More particularly, the invention pertains to apparatus for applying shrink wrap and/or other tape or tape-like materials to a composite structure formed on a tooling mandrel or the like. BACKGROUND ART Composite reinforced structures are typically useful where light weight and strength are required, and include such items as shrouds, casings, shafts, tanks, airfoils and fuselage panels in the aerospace technology. It is recognized that composite structures would be useful in many other applications, were it not for the relatively high cost. One item of significant expense in producing composite structures is found in the step of applying an overwrap release material to the uncured composite structure and/or the tooling. In the manufacture of composite structures by winding of fiber tows on a mandrel or other tool, a layer of release material may be first placed on the tooling, fiber placement/winding is performed, and the fiber-wound tool is cured to harden the component before removing it from the tooling. Use of an overwrap material which easily releases off component surfaces, or if so used the tool, permits ready consolidation of the uncured composite structure, or if so used easy separation of the component from the tool, following curing. A shrink-wrap overwrap material is used to facilitate the consolidation of the composite structure during the curing process by the shrink-wrap material exerting a force on the composite structure due to the heating and attendant shrinkage of the shrink-wrap material, typically the composite structure being cured in an autoclave. In the case of the tool, it is very important that none of the resin of the composite component touch the mandrel surface and adhere thereto because removal of the product from the mandrel is made difficult. Typically, shrink-wrap materials, such as a suitable shrink-wrap plastic material, or release materials such as paper or a non-adhering film of plastic, such as polyethylene, have been or are applied, in sheet form or other suitable forms, to the tool by hand The shrink-wrap materials and release materials have also been produced and applied in the form of a tape In a typical process of overwrapping, an operator holds a spool of tape in a gloved hand, and with the other hand guides the tape onto the composite structure or a rotating mandrel, letting it wrap itself around the composite structure or mandrel while attempting to manually maintain constant tape tension and tape advance Several deficiencies in this method are obvious First, the operator must simultaneously control the continuously changing advancing placement of the tape on the composite structure or mandrel and the continuously attempt to keep as constant tension as possible on the tape Even if the mandrel is rotated at a slow speed, tape application will not be uniform m each instance, nor uniform from composite structure or mandrel to the next The manual application requires a high degree of mental concentration of the operator and a high degree of manual dexterity of the operator, and a brief lapse of either may require rework of an overwrap, which may be difficult Even highly qualified personnel may produce defective overwrapping of composite structures, mandrels, or tools, leading to irregularities in the finished surface of the finished product Such defects include irregular overlapping of layers, varying thicknesses, voids, etc and are particularly prevalent in products of complex geometric shapes Each unit of composite structure product fabricated by fiber placement or winding process on a mandrel or other suitable tooling can have a shrink-wrap material applied thereover at the end of the placement or winding process to help consolidate the uncured fiber forming the composite structure during the curing thereof in an autoclave The shrmk-wrap material being wound over the uncured composite structure is a relatively lengthy time consuming process The length of time for the winding of the shrmk-wrap material over the uncured composite structure increases with the geometric shape and size of the composite structure Large and complex shaped geometric structures require greater winding time than small simple geometric structures Similarly, each unit of composite product fabricated by fiber placement/winding on a mandrel requires an initial overwrapping of the tooling e g mandrel with a release material, prior to fiber placement/winding The time for overwrapping is relatively lengthy, particularly for tooling of complex geometric shape A great deal of effort has been expended in the development of fiber placement/winding machines, as characterized in United States Patents 4,872,619, 4,877, 193, and 4,907,754 of Vaniglia, United States Patent 4,943,338 of Wisbey, United States Patent 5,045,147 of Benson et al., United States Patent 5,290,389 of Shupe et al., and United States Patent 5,472,553 of Roberts. However, the wrapping of uncured composite structures and/or the overwrapping of tooling with shrink-wrap materials or release materials, respectively, has generally remained as a manual process, particularly for uncured composite structures and/or tooling for composite structures of complex geometric shape. In United States Patent 4,938,824 of Youngkeit, a method for forming and applying composite tape to a mandrel is described. The composite tape is formed by fiber winding on a mandrel covered with "a suitable backing film or paper (not shown) such as, for example, polyethylene, nylon, or another suitable plastic film on the mandrel...." There is no mention of how the backing material is placed on the mandrel. In this reference, the composite material on the mandrel is subsequently cut into strips for subsequent application in tape form to a product mandrel, and the backing material is retained on the backside of the composite tape during intermediate storage on reels. There is a need in the art for an apparatus capable of automated placement of one or more tapes of overwrap material on tooling, such as a rotatable mandrel. There is a need for such an apparatus which may be readily adapted to control by existing automated machines at a composite manufacturing site, thereby avoiding the high cost of additional computer manipulable multi-axis machines, computer programming, and the high cost of hand placement of wrapped materials. Particularly, there is a need for such an apparatus for the wrapping or winding of shrink-wrap materials over an uncured composite structure to replace the hand application thereof presently occurring. Furthermore, installation of a separate machine for the wrapping of shrink-wrap material over an uncured composite structure or the overwrapping of a mandrel or other tooling, will include a carriage of a size which may require a separate station for overwrapping. Thus, it would be necessary to physically transfer the uncured composite structure to another station where the machine is located for the wrapping of the shrink-wrap material after the wrapping of the shrink-wrap material or the transfer of the mandrel from an overwrap station to a fiber placement station after an overwrapping step Such use of a separate machine for such wrapping being undesirable from a process standpoint, a facilities standpoint, and a cost standpoint Therefore, it is very desirable to have an apparatus which may be attached to an existing multi-axis fiber placement/winding machine after the completion of the fiber placement/winding to form the uncured composite structure or prior to the formation of the uncured composited structure on an mandrel or other suitable tooling, the apparatus being used for the wrapping of shrink-wrap material over the uncured composite structure or the overwrapping of the mandrel or other suitable tooling before the formation of the uncured composite structure thereon DISCLOSURE OF INVENTION The invention comprises a multi-spool overwrap tape material end-effector apparatus which is attachable on multi-axis fiber placement machines The end-effector apparatus is useful for placing shrink wrap material on uncured composite structures having a complex geometric shape of any size and other overwrap materials, such as release agents, for example, on mandrels or suitable tooling of complex geometry of any size, or the interior thereof The end-effector apparatus is lightweight, l e may be manually lifted, and is readily attached to and detached from a multi-axis fiber placement/winding machine of the type disclosed in United States Patent 4,867,834, I e a 6- or 7-axιs, or any desired number axis, multi-axis fiber placement/winding machine In the end-effector apparatus of the invention, shrink-wrap materials, overwrapping tapes, and/or any other desired materials are dispensed from at least one, but preferably three or more spools under tension, to a guide roller or redirect roller and then to an application roller for application of the tape(s) to un uncured composite structure, a mandrel, or any other suitable tooling Each channel of tape application is independently controlled with respect to unspoolmg tension, and the unspoolmg speed is dependent upon the mandrel shape and turning speed (RPM) Control of the fiber placement/winding machine permits delivery of the tape or tapes either upon the uncured composite structure, the mandrel surface, the surface of the other suitable tooling, or at a standoff distance from any of such A sensor arm serves several purposes First, the arm senses the diameter of the tape spool for controlling the tension placed on the unspooling tape. Second, the arm also prevents the tape from excessive unwinding; e.g., when the apparatus is inverted. The end-effector apparatus of the invention provides a short, simple, direct, non- convoluted tape delivery path from each tape spool to the delivery roller, promoting reliable operation and precise control of tape placement onto the tooling, as well as facilitating precise termination and re-start of tape placement. The end-effector apparatus of the invention provides for very consistent and controlled wrapping of uncured composite structures with shrink-wrap material or overwrapping of mandrels or other suitable tooling with a suitable release material. Composite structures are produced using the end-effector apparatus of the present invention which have consistently smoother, more even surfaces. Voids are generally eliminated and ply compactions and consolidations of the fiber materials are more consistent and repeatable than in hand applied overwraps. Processing time of the formation and curing of the composite structure is also reduced because of the automated operation of the end-effector apparatus and because of the simultaneous multiple tape application in a preferred embodiment of the apparatus. BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated in the following exemplary figures. FIG. 1 is an isometric view of an overwrap tape end-effector apparatus of the invention attached to a multi-axis fiber placement/winding machine and applying three parallel tapes of a shrink-wrap material to an uncured composite structure having a complex geometric shape or overwrap material to a mandrel or other suitable tooling having a complex geometric shape; FIG. 2 is a side view of an overwrap tape end-effector apparatus of the invention; FIG. 3 is a frontal view of an overwrap tape end-effector apparatus of the invention, in which belt guards are partially deleted to expose the drive assemblies; FIG. 4 is an enlarged side view of a spool holder drive of an overwrap tape end- effector apparatus of the invention; FIG. 5 is a cross-sectional bottom view of a spool holder drive of an overwrap tape end-effector apparatus of the invention, as taken along line 5-5 of FIG. 4 but without a tape spool; and FIG. 6 is a cross-sectional longitudinal view of a final roller assembly of an overwrap tape end-effector apparatus of the invention, as taken along line 6-6 of FIG. 5. The drawings of the end-effector apparatus of the present invention will be better understood when taken in conjunction with the description of the invention hereafter. BEST MODE FOR CARRYING OUT THE INVENTION Referring to drawing FIGS. 1 through 6, the structure and operation of a preferred embodiment of a multi-spool overwrap tape end-effector 10 apparatus of the present invention will be described. As shown, the overwrap tape end-effector apparatus 10 of the invention has a frame 12 which is configured for attachment to a member 20 of an multi-axis fiber placement machine for delivering a wrapping material 30, such as a shrink wrap plastic film 30 or other desired material, as tapes 3 ON 30B and 30C to an uncured composite structure 40, a tooling mandrel 40, or other suitable tooling 40, or the interior of other suitable tooling 40. Uncured composite structure 40, or mandrel 40, or other suitable tooling 40, or the interior thereof, is shown as being rotatable in direction 24 about its central axis 26, desired rotational axis 26, or any desired axis 26. The frame 12 is shown in drawing FIGS. 1 through 3 as including parallel side plates 14A and 14B which are joined by backplate 16, cross plate 18 and base 22. The various plates 14N 14B, 16, 18 and base 22 are connected by fasteners 38, typically screws. The frame 12 is shown with a latch plate 52 on base 22 and a quick-release clamp 54 with a handle 56 mounted on each side plate 14 A, 14B. The frame 12 may be quickly attached and removed from a multi-axis fiber placement machine 20. The major non-motor components of end-effector apparatus 10 may be made of lightweight materials, e.g. aluminum, titanium, magnesium, a composite material structure, etc., enabling it to be manually lifted for installation and removal. In addition, portions of the planar portions, i,e. frame members 14A, 14B, 16, 18 and 22, as well as the flanges 66, 70 may be cut out to further lighten the end-effector apparatus. At least one tape-feeding assembly 28, as depicted in drawing FIGS 4 and 5, is mounted to the backplate 16 of frame 12 The embodiment of the end-effector apparatus 10 shown in drawing FIGS 1 through 3 has three tape-feeding assemblies 28N 28B, 28C for applying three tapes 30 A, 30B, and 30C which are controllably spaced from each other The parts of each particular tape-feeding assembly 28A, 28B, and 28C will be identified herein by the corresponding suffix A, B, or C following the identification numeral In particular, the numerals 28, 30, 32, 34, 36, 46, 48, 50, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 94, 96, 98, 106, and 108, without the suffix N B, or C, denoting the part in general As depicted in drawing FIGS 2-5, the tape-feeding assembly 28 includes a stanchion bar 32 which is mounted on the backplate 16 for supporting a rotatable spool holder 34, a torque servo motor 50 and a belt drive assembly 36 between the motor and the spool holder The stanchion bar 32 is shown with a center line 136 A spool 60 of overwrap tape is insertable in the spool holder 34 for unspoolmg under tension to a guide roller 42 (also known as a redirect roller) and then to an application roller 44 from which the tape is applied to the tooling mandrel 40 As configured, spool holder 34 comprises an inner hub 64 and an outer hub 68 which are together mounted on a rotatable spool holder shaft 72 passing through journal 74 on the stanchion bar 32 Preferably, journal 74 is fitted with bearings 76 The spool holder 34 rotates in direction 58 as the tape 30 is unspooled toward the tooling mandrel 40 The torque servo motor 50 applies movement to take up slack in the tape as the tape is being applied to the uncured composite structure or the mandrel or tooling, or drag to the unspoolmg of the tape, or resistance to rotation of the spool holder 34 through a toothed, e g timing belt 78 rotating on a motor connected pulley 82 and a pulley 80 fixed to spool holder shaft 72 Each spool holder shaft 72 with attached pulley 80 and spool holder 34 rotates about an axis 84 In the instance where the distance between the end-effector apparatus 10 and the work surface of the uncured composite structure, mandrel, or other suitable tooling is large, the ability to control the slack in the tape 30 as it is being applied to the work surface through the use of the servo motor 50 is desirable Each guide roller 42A, 42B, and 42C is independently rotatable on shaft 86 about axis 88 Each application roller 44 A, 44B and 44C is independently rotatable on shaft 90 about axis 92 In the embodiment shown in the drawing figures, axes 84N 84B, 84C, 88 and 92 are parallel An inner flange 66 is affixed to the inner hub 64, which is affixed to the spool holder shaft 72 An outer flange 70 is affixed to outer hub 68 Outer hub 68 with attached outer flange 70 are configured to slidingly fit on shaft 72 for quick removal to permit installation of a spool 60 of tape, or removal thereof Optionally, any type of quickly openable retaining device, not shown, may be used if desired to lock the outer hub 68 and flange 70 to the inner hub 64 and inner flange In each tape-feeding assembly 28, a sensor arm 46 with a sensor roller 48 at an outer end 114 is pivotably mounted on a sensor bracket 106 extending from the stanchion bar 32 for simultaneously sensing the diameter of the circumferential surface 62 of the spool 60 of tape in the spool holder 34, and inwardly compressing the tape on spool 60 to prevent inadvertent unwinding The sensor roller 48 is shown as having a shaft 132 rotatable about axis 134 The sensor arm 46 is biased by a spring, shown here as a coil spring 108 extending between pin 110 and pin 112. A transducer 120 sensitive to rotational position is mounted at the sensor arm 46-bracket 106 interface to exert an electrical potential as a function of rotational angle 1 18 The transducer 120 may, for example, comprise a variable resistance potentiometer type instrument A first portion 122 of the potentiometer 120 is firmly held in a slot 126 in the sensor arm 46 by a tightening screw 128 Another portion, not visible, is held by the bracket 106, so that rotation of the sensor arm 46 in direction 130 changes the resistance and thus the potential of a current passed through the potentiometer 120 The potential signal from the transducer 120 is routed to a control unit (not shown) which, in turn, controls the servo motor 50 thereby controlling the tension in the tape by controlling the motor output. By way of example, a typical potentiometer 120 useful for this purpose is an Allen-Bradley Type J of 50K ohms maximum resistance Any instrument which generates an electrical potential relative to an angular position may be used, however As shown in drawing FIGS 3 and 5, each tape feeding assembly 28 A, 28B and 28C is driven by a corresponding servo motor 50N 50B, 50C with rotating shaft 94 The toothed belt 78 transmitting tension force from the motor 50 through pulleys 82 and 80 to the spool holder 34 has a protective shield 98 held in place by standoffs 100 from the stanchion bar 32. The DC servo motor 50 is shown mounted on the stanchion bar 32 with screws 102 passing through slots 104 in the stanchion bar 32, for belt adjustment. Turning now to drawing FIG. 6, a detailed view of an application roller assembly 140 is pictured. Three application rollers 44N 44B and 44C are spacedly mounted on roller shaft 90 with bearings 142 A, 142B, 142C, respectively, to be independently rotatable about axis 92. Like the guide rollers 42A, 42B and 42C, the application rollers 44 A, 44B and 44C are free-wheeling, i.e. freely rotatable. The application rollers 44 are mounted on the shaft 90 to accommodate a given tape width 144 and provide a desired spacing. Adjustments in tape spacing may be made without making changes to the axial spacing of the spool holders 34A, 34B and 34C. By varying the placement of clamps 54 and/or other connecting devices, the end-effector apparatus 10 may be easily adapted for mounting on and use with a wide variety of fiber placement machines 20. For example, the embodiment shown in the drawing figures herein is mountable on a multi-axis fiber placement machine 20 of the type shown in United States Patent 4,867,834. In this example, a fiber winding assembly used as part of the multi-axis fiber placement machine 20 may be simply loosened, turned 90 degrees and the end-effector 10 attached to the machine. The transformation from a fiber winding machine to an wrapping device 10 may be accomplished easily and quickly. The continuous changes in orientation required for accurate placement of the overwrap material are programmable in the existing computer of the fiber placement machine 20. Preferably, a fiber placement/winding machine 20 capable of motion typically in at least 6 degrees of freedom, although a machine having any desired number of degrees of freedom may be used, is combined with the tape winding end-effector apparatus 10 described herein. The overwrap end-effector as described herein increases the tape laydown rate, provides a desired spacing between tapes where the spacing may be programmed to be constant or varying over the mandrel surface. Because of the computer control, the program may be readily changed at will to avoid defects and provide products of high quality and repeatability. The consistent tape tension and computer controlled laydown pattern results in uniformity and manufacturing repeatability of the composite structure product. The present invention has been described in terms of an illustrated, preferred embodiment. Additional modifications will readily be recognized by those of ordinary skill in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative device, shown and described herein. Accordingly, various modifications including additions and deletions may be made without departing from the spirit and scope of the general inventive concept and embodiments as defined by the appended claims and their equivalents.

Claims: CLAIMS What is claimed is' 1. An apparatus for applying a tape to a work surface, comprising: a frame removably securable to a support structure for supporting the apparatus; a tape feeding assembly fixed to said frame, said tape feeding assembly comprising: a stanchion bar attached to said frame; a spool holder rotatably attached to said stanchion bar for holding a spool of tape for dispensing said tape; a guide roller assembly with a first rotatable guide roller for guiding a tape from a spool, said guide roller assembly fixed to said frame; an application roller assembly with a first rotatable application roller for accepting said tape from said first guide roller and applying said tape to a work surface, said application roller assembly fixed to said frame; and apparatus for controlling said tape while applying said tape to said work surface. 2. The apparatus of claim 1, further comprising a spool mounted on said spool holder, said spool for holding and dispensing a tape, said tape wound on said spool and having an outer peripheral surface. 3. The apparatus of claim 1, wherein said support structure comprises: a continuously attitude-controllable component of a multi-axis machine by which the attitude of said apparatus is controlled. 4. The apparatus of claim 3, further comprising a computer for controlling the attitude of said apparatus. 5 The apparatus of claim 2, wherein said tension apparatus for maintaining a constant tension on said tape comprises a servo motor, measuring apparatus for continuously measuring the diameter of spooled tape on said spool, a servo amplifier and feedback apparatus used for controlling said servo motor based on the spooled tape diameter to control said tape during unspoolmg thereof 6 The apparatus of claim 5, wherein said measuring apparatus for continuously measuring the diameter of spooled tape comprises a sensor arm swivelable about an axis at a first end thereof and having a sensor roller at the opposite end thereof, said sensor roller biased to ride on the outer periphery of said spooled tape, and a feedback transducer configured to provide an electrical signal as a function of the angular position of said sensor arm and transmitting said electrical signal to said servo amplifier 7 The apparatus of claim 6, wherein said sensor roller is biased to ride on said spooled tape by a resilient member, the resilient member including a spring 8 The apparatus of claim 1 , wherein said apparatus for controlling said tape is programmable 9 The apparatus of claim 1, wherein said apparatus for controlling said tape is programmable to provide a variable control of said tape 10 The apparatus of claim 1 , wherein said tape comprises a polymeric shrink-wrap film which conformably shrinks to the shape of the work surface when heated 11 The apparatus of claim 1, wherein said tape comprises a release layer for separating a composite structure from a work surface 12 The apparatus of claim 1, further comprising clamp apparatus for detachably attaching said apparatus to a fiber machine having a computer connection for the continuous attitude control thereof 13 The apparatus of claim 12, wherein said computer is programmable to continuously control the attitude of the application roller of said apparatus for applying said tape on the work surface 14 The apparatus of claim 12, wherein said computer is programmable to continuously control the attitude of the application roller of said apparatus to dispense said tape at a controllable distance from said work surface 15 The apparatus of claim 12, wherein said computer is programmable to continuously control the servo motor to control the dispensing of said tape at a controllable distance from said work surface 16 The apparatus of claim 1, wherein said work surface comprises an exterior surface of an uncured composite structure 17 The apparatus of claim 1, wherein said work surface comprises an interior surface of an uncured composite structure 18 The apparatus of claim 1, wherein said work surface comprises an exterior surface of a rotatable mandrel for forming a composite structure 19 The apparatus of claim 1, wherein said work surface comprises an interior surface of a mandrel for forming a composite structure 20 The apparatus of claim 1, wherein said work surface comprises an exterior surface of a stationary mandrel for forming a composite structure 21 The apparatus of claim 1. wherein said work surface comprises an exterior surface of rotatable tooling for forming a composite structure 22 The apparatus of claim 1, wherein said work surface comprises an exterior surface of stationary tooling for forming a composite structure 23 The apparatus of claim 1 , wherein said work surface comprises an interior surface of rotatable tooling for forming a composite structure 24 The apparatus of claim 1, wherein said work surface comprises an interior surface of stationary tooling for forming a composite structure 25 An apparatus for applying a plurality of laterally- spaced tapes to a work surface, comprising a multi-axis fiber machine having a computer for controlling the attitude of a head mount thereon, an overwrap tape end-effector apparatus mountable on said head mount for attitude control by said computer, said end-effector apparatus comprising a frame mountable on said head mount; a plurality of tape feeding assemblies attached to said frame, each said tape feeding assembly configured for independent control of the tension and speed of said tape, each said tape feeding assembly comprising' a rotatable spool holder for holding a spool of overwrap tape, a servo motor for applying tension to said spool holder as tape is dispensed therefrom; control apparatus for determining the diameter of said tape spool and controlling said servo motor as a function thereof, and roller apparatus for redirecting and applying said dispensed tape to said work surface 26 The apparatus of claim 25, wherein said fiber machine is configured for attitude control of the head mount 27 The apparatus of claim 25, wherein said plurality of tape feeding assemblies comprises at least two or more tape feeding assemblies 28 The apparatus of claim 25, wherein said roller apparatus comprises a plurality of independently rotatable redirect rollers and a plurality of independently rotatable application rollers 29 The apparatus of claim 25, wherein said application rollers are mounted on a common shaft to rotate coaxially 30 The apparatus of claim 25, wherein the lateral spacing of said tapes is preset to provide for overlapping a portion of at least one tape of said tapes applied to said work surface 31 The apparatus of claim 25, wherein the control apparatus for determining the spool diameter comprises a sensor arm having a first end with a pivot axis and a rotation dependent transducer, and a second end having a sensor roller rotatable on the circumferential surface of said spool of tape, whereby a potential signal dependent on said roller position is generated by said transducer for control of said tension produced by said servo motor 32 The apparatus of claim 31, wherein said sensor roller is spring mounted for compression against said circumferential surface 33 The apparatus of claim 25, wherein said work surface comprises an uncured composite structure 34 The apparatus of claim 25, wherein said work surface comprises a rotatable mandrel 35 The apparatus of claim 25, wherein said work surface comprises a stationary mandrel 36 The apparatus of claim 25, wherein said work surface comprises rotatable tooling 37 The apparatus of claim 25, wherein said work surface comprises stationary tooling 38 The apparatus of claim 25, wherein said tension is controllable by said servo motor to be constant 39 The apparatus of claim 25, wherein said tension is controllable by said servo motor to follow a variable pattern of the amount of tension. 40 A tape end-effector apparatus for attachment to a fiber placement machine, comprising a frame removably securable to an attitude controllable structure of a fiber placement machine, a plurality of tape feeding assemblies fixed to said frame, each said tape feeding assembly configured for independent control of the control of the tension and the speed of the tape, each said tape feeding assembly comprising- a rotatable spool holder for holding a spool of overwrap tape, a servo motor for applying tension to said spool holder as tape is dispensed therefrom and directed to a work surface, control apparatus for determining the diameter of said tape spool and controlling said servo motor as a function thereof; and roller apparatus for redirecting and applying said dispensed tape to said work surface 41 The apparatus of claim 40, wherein said fiber placement machine is configured for attitude control 42 The apparatus of claim 40, wherein said plurality of tape feeding assemblies comprises at least two ar more assemblies 43 The apparatus of claim 40, wherein said roller apparatus comprises a plurality of independently rotatable redirect rollers and a plurality of independently rotatable application rollers 44 The apparatus of claim 40, wherein said application rollers are mounted on a common shaft to rotate coaxially 45 The apparatus of claim 40, wherein the lateral spacing of said tapes is preset to provide for overlapping of at least one tape of said tapes in sequential rotations of said work surface 46 The apparatus of claim 40, wherein control apparatus for determining the spool diameter comprises a sensor arm having a first end with a pivot axis and a rotation dependent transducer, and a second end having a sensor roller rotatable on the circumferential surface of said spool of tape, whereby a potential signal dependent on said roller position is generated by said transducer for control of said tension produced by said servo motor 47 The apparatus of claim 46, wherein said sensor roller is spring mounted for compression against said circumferential surface 48 The apparatus of claim 40, wherein said work surface comprises an uncured composite structure 49 The apparatus of claim 40, wherein said work surface comprises a rotatable mandrel 50 The apparatus of claim 40, wherein said work surface comprises a stationary mandrel 51. The apparatus of claim 40, wherein said work surface comprises rotatable tooling. 52. The apparatus of claim 40, wherein said work surface comprises stationary tooling. 53. The apparatus of claim 40, wherein said tension is controllable by said servo motor to be constant. 54. The apparatus of claim 40, wherein said tension is controllable by said servo motor to follow a variable pattern. 55. A tape end-effector apparatus for attachment to a fiber winding machine, comprising: a frame removably securable to an attitude controllable structure of a fiber placement machine; a plurality of tape feeding assemblies fixed to said frame, each said tape feeding assembly configured for independent control of the control of the tension and the speed of the tape, each said tape feeding assembly comprising: a rotatable spool holder for holding a spool of overwrap tape; a servo motor for applying tension to said spool holder as tape is dispensed therefrom and directed to a work surface; control apparatus for determining the diameter of said tape spool and controlling said servo motor as a function thereof; and roller apparatus for redirecting and applying said dispensed tape to said work surface. 56. The apparatus of claim 55, wherein said fiber placement machine is configured for attitude control. 57. The apparatus of claim 55, wherein said plurality of tape feeding assemblies comprises at least two ar more assemblies. 58 The apparatus of claim 55, wherein said roller apparatus comprises a plurality of independently rotatable redirect rollers and a plurality of independently rotatable application rollers 59 The apparatus of claim 55, wherein said application rollers are mounted on a common shaft to rotate coaxially 60 The apparatus of claim 55, wherein the lateral spacing of said tapes is preset to provide for overlapping of at least one tape of said tapes in sequential rotations of said work surface 61 The apparatus of claim 55 wherein control apparatus for determining the spool diameter comprises a sensor arm having a first end with a pivot axis and a rotation dependent transducer, and a second end having a sensor roller rotatable on the circumferential surface of said spool of tape, whereby a potential signal dependent on said roller position is generated by said transducer for control of said tension produced by said servo motor 62 The apparatus of claim 61, wherein said sensor roller is spring mounted tor compression against said circumferential surface 63 The apparatus of claim 55, wherein said work surface comprises an uncured composite structure 64 The apparatus of claim 55, wherein said work surface comprises a rotatable mandrel 65 The apparatus of claim 55, wherein said work surface comprises a stationary mandrel 66 The apparatus of claim 55, wherein said work surface comprises rotatable tooling 67 The apparatus of claim 55, wherein said work surface comprises stationary tooling 68 The apparatus of claim 55, wherein said tension is controllable by said servo motor to be constant 69 The apparatus of claim 55, wherein said tension is controllable by said servo motor to follow a variable pattern 70 A method for applying tape to a work surface, comprising providing an apparatus for dispensing tape to a work surface, providing a multi-axis fiber placement machine having an arm having a support structure thereon, mounting said apparatus on the arm of said multi-axis machine, providing a spool of said tape, mounting said tape on the tape feeding assembly, dispensing said tape from said apparatus to said work surface, and controlling the tension of said tape while applying said tape to said work surface 71 The method of claim 70, wherein said apparatus for wrapping a tape comprises a frame removably securable to a support structure for supporting the apparatus, a tape feeding assembly fixed to said frame, said tape feeding assembly comprising a stanchion bar attached to said frame, a spool holder rotatably attached to said stanchion bar for holding a spool of tape for dispensing said tape, a guide roller assembly with a first rotatable guide roller for guiding a tape from a spool, said guide roller assembly fixed to said frame, an application roller assembly with a first rotatable application roller for accepting said tape from said first guide roller and applying said tape to a work surface, said application roller assembly fixed to said frame, tension apparatus for controlling the tension on said tape while applying said tape to said work surface, and a spool mounted on said spool holder for holding and dispensing a tape of overwrap material, said tape wound on said spool and having an outer peripheral surface 72 The method of claim 70, further comprising controlling said apparatus, said support structure comprises a continuously attitude- controllable component of a multi-axis fiber placement machine by which the attitude of said apparatus is controlled 73 The method of claim 70, further comprising controlling said apparatus said support structure comprises a continuously attitude- controllable component of a multi-axis fiber winding machine by which the attitude of said apparatus is controlled 74 The apparatus of claim 72, wherein said fiber placement machine includes a computer 75 The apparatus of claim 73, wherein said fiber winding machine includes a computer 76 The method of claim 71, wherein said tension apparatus for maintaining a constant tension on said tape comprises a servo motor, measuring apparatus for continuously measuring the diameter of spooled tape on said spool, a servo amplifier and feedback apparatus for controlling said servo motor based on the spooled tape diameter to provide a preset tension on said tape during unspoolmg thereof 77 The method of claim 70, wherein said measuring apparatus for continuously measuring the diameter of spooled tape comprises: a sensor arm swivelable about an axis at a first end thereof and having a sensor roller at the opposite end thereof, said sensor roller biased to ride on the outer periphery of said spooled tape; and a feedback transducer configured to provide an electrical signal as a function of the angular position of said sensor arm and transmitting said electrical signal to said servo amplifier 78 The method of claim 77, further comprising' biasing said sensor roller to ride on a portion of said spooled tape, said sensor roller biased to ride on said spooled tape by a resilient member. 79 The method of claim 70, further comprising: programming said tension apparatus to provide a constant tension, said tension apparatus for controlling the tension includes a tension apparatus programmable to provide a constant tension. 80. The method of claim 70, further comprising: programming said tension apparatus to provide a variable tension, said tension apparatus for controlling the tension includes a tension apparatus programmable to provide a variable tension. 81 The method of claim 70, further comprising: said tape comprising a release layer for separating a composite structure from a work surface. 82. The method of claim 70, further comprising: said tape comprising a polymeric shrink-wrap film which conformably shrinks to the shape of the work surface when heated. 83 The method of claim 70, further comprising providing clamp assemblies for detachably attaching said apparatus to said fiber placement machine having a computer for continuous attitude control thereof, and releasing said apparatus from said fiber placement machine 84 The method of claim 83, further comprising continuously controlling the attitude of the application roller of said apparatus including the use of a computer for control of the attitude of the application roller, said computer including a programmable computer to continuously control the attitude of the application roller of said apparatus for applying said tape on the work surface 85 The method of claim 83, further comprising controlling the distance of said application roller of said apparatus from said work surface, said computer including a programmable computer to continuously control the attitude of the application roller of said apparatus to dispense said tape at a controllable distance from said work surface 86 The method of claim 70, wherein said work surface comprises an exterior surface of a rotatable mandrel for forming a composite structure 87 The method of claim 70, wherein said work surface comprises an interior surface of a rotatable mandrel for forming a composite structure 88 The method of claim 70, wherein said work surface comprises an exterior surface of a stationary mandrel for forming a composite structure 89 The method of claim 70, wherein said work surface comprises an interior surface of a stationary mandrel for forming a composite structure

Inventors: FUJIMOTO KAZUTOSHI DI, MILLER LLOYD G, FUJIMOTO, KAZUTOSHI DI, MILLER, LLOYD, G.
Applicants: ALLIANT TECHSYSTEMS INC, ALLIANT TECHSYSTEMS INC.
Application year: 2000
Main classification: B65H35
IPC codes: B65H19, B65H35