Tape Laying Head

Abstract

A tape laying head configured to lay tow material into a mold for building a composite structure is provided, the tape laying head including a shear mechanism configured to receive tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material during steering of the tow material; and a tension control system configured to control the lateral component of the driving force acting on the tow material to be equal to or less than a maximum lateral friction force associated with the shear mechanism by varying the tension applied to the tow material by the tension control system and monitoring the driving force.

Description

[Technical field]

[0001] Embodiments of the present invention relate to a tape laying head configured to lay tow material onto a mold in building a composite structure, a controller for use in a tension control system of a tape laying system, related control methods, and related computer readable media. [Background technology]

[0002] Composite materials, having a matrix material (e.g., a thermoset resin) that forms a matrix that holds elongated reinforcing elements (e.g., carbon fibers), are commonly used to provide strong, lightweight structures. Such materials are now used in a wide range of different applications, from exercise equipment to the aerospace industry.

[0003] The composite structure may be formed using tapes or tows of substantially parallel carbon fibers (though a tape may include multiple tows, the terms "tape" and "tow" are used interchangeably herein). The tows may be pre-impregnated with a matrix material or the matrix material may be added at a later time in the manufacturing process. The tows are laid down in layers onto a mold structure. The laid down mold structure is then heated under pressure, for example in an autoclave, to polymerize the matrix material and form the composite structure (which is then removed from the mold).

[0004] Laying a tow onto a mold structure may require the tow to be routed through one or more bends or curves. This may affect the parallel arrangement of the carbon fibers in the tow because the fiber path lengths differ depending on the location of the tow relative to the width of the tow (e.g., on the inside or outside of the bend or curve). The results may include structural defects such as, for example, carbon fibers buckling or moving into a non-parallel arrangement or not aligning with the intended tow lay path. These problems may adversely affect the properties of the resulting composite structure.

[0005] There is also a general desire to improve acceleration and deceleration times for the tow laying process, as this can have a significant impact on the overall speed of the tow laying operation, which typically involves multiple stop-start steps that require deceleration and acceleration.

[0006] US Patent No. 5,399,633 discloses an apparatus used to form a wavy pre-impregnated tow material. However, the document does not provide any teaching regarding the laying of the resulting tow into a mold structure, and therefore the teaching is unrelated to the apparatus and technique for laying the resulting tow, and the disclosed apparatus is not suitable for such purpose. In addition, a complex apparatus is required to alleviate the problem of loosening of the reinforcing elements as a result of changing the rotation speed requirements of the rollers. Furthermore, the fixed width of the combination rollers and pinch rollers limits the degree of waviness that can be achieved in the pre-impregnated material produced using this apparatus. In addition, there is no disclosed means to allow each tow path in the structure to have a different angular change relative to a reference axis.

[0007] US Pat. No. 5,399,633 relates to a machine for coating a surface with a fiber / resin composite material in strip form. According to this document, the head for laying the strip on the surface is pivotally mounted on its support, the central vertical plane of which always remains perpendicular to the contact line of the strip with the surface, regardless of the unevenness of the surface. This machine is said to be used for manufacturing various structures in the aeronautical construction field.

[0008] US Patent No. 5,399,633 discloses an automated tape head assembly for a multi-axis tape laying machine, including a tape supply reel and a tape compression roller. The tape from the supply reel passes through the space between two independent structures of the supply reel and the compression roller, which define a tape path that substantially maintains the zero Gaussian curvature of the tape. The tape path is a curved path, referred to as a compliant loop, which is said to result in a substantially or partially unconstrained curved path between the supply reel and the compression roller. This structure allows the compression roller to shift laterally and vertically relative to the supply reel, while the supply reel is generally said to be in a fixed position relative to the tape head assembly. This structure also reportedly allows the compression roller to roll, steer and follow the natural path of the fiber tape quite independently of the supply reel.

[0009] US Patent No. 5,399,633 teaches a method that involves using a processing element to compress the strip and limit the twisted portion at the end. The strip is eccentrically twisted in the twisted portion so that the strip acquires a lateral curvature at the processing element. The direction and degree of twist are said to be selected so that longitudinal differences in the twisted portion are compensated.

[0010] US Patent No. 5,399,633 teaches a reinforcing strip that is laid down on a rotating receiving surface during the manufacture of a tire. The strip passes through a guide that is moved in alternating transverse directions relative to the travel path of the strip, so that the strip is laid down in a wave-like manner on the receiving surface. The amplitude of the alternating transverse movements is varied as a function of the ratio of (a) the speed of the portion of the strip approaching the guide and (b) the speed of the receiving surface. Between the guide and the receiving surface, the strip is rotated 90 degrees about its longitudinal axis so that it is laid down tangentially on the receiving surface.

[0011] Patent document 6 discloses a tow placement head member for laying a tow tape containing reinforcing fibers and a matrix or binder material, the tow placement head member being used to form a variable angle tow composite structure, a pinch device configured to receive the tow tape and allow the tow tape to pass therethrough, the pinch device including a tow feed roller and a tow feed shoe configured to guide the tow tape toward a compression shoe, and a compression shoe configured to receive the tow tape from the pinch device and press the tow tape against a surface on which the tow tape is to be laid, the pinch device being configured to apply a shear deformation to a portion of the tow tape between the compression shoe and the pinch device.

[0012] US 2007 / 0133963 A1 discloses a fiber application device including a fiber application head with an application roller for manufacturing parts made of composite material. The fiber application head further includes a guide system for guiding the fibers onto the application roller and / or means for applying resin to each fiber as it leaves the guide system. The fiber application device may also include a fiber storage system and conveying means for conveying the fibers from the fiber storage system to the application head. The conveying means may comprise flexible tubes, each tube being capable of receiving a fiber in its internal channel. The conveying means may further include a tension limiting system, arranged between the application head and the storage system. The fiber application device may further include a system for moving the application head.

[0013] US Patent No. 5,399,633 teaches a method of removing a backing film from a roll of tape used for tape laying or fiber placement, the method comprising unwinding the tape from the spool while the backing film is still attached to the tape, extending a portion of the tape with the backing film still attached around a take-up roller, partially removing the backing film from the tape and attaching the backing film to the take-up roller, extending the portion of the tape with the backing film removed from the take-up roller to a dancer roller, and continuously winding the backing film around the take-up roller as the take-up roller is driven by the movement of the tape around the take-up roller as the tape is moved from the spool to the dancer roller, the take-up roller comprising a rotatable take-up roller driven solely by the movement of the tape around the take-up roller.

[0014] US Patent No. 5,399,633 discloses a fiber tensioning device for use with a spool of fiber from which the fiber is drawn, the device including a support, a hub rotatably mounted on the support, the hub adapted to have a fiber spool mounted on the hub for rotation with the hub, the hub rotatably mounted for rotation about an axis that is stationary relative to rotation of the hub about the axis, and means for applying a drag force to the fiber as it is drawn from the spool, the drag force applying means being disposed on the hub and including a biasing means, a portion of the biasing means being fixed to the axis. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] U.S. Patent No. 6,453,962 [Patent Document 2] French Patent No. 2539122 [Patent Document 3] US Patent Application Publication No. 2009 / 032195 [Patent Document 4] European Patent No. 2508327 [Patent Document 5] US Patent Application Publication No. 2005 / 139324 [Patent Document 6] British Patent No. 2492594 [Patent Document 7] US Patent Application Publication No. 2009 / 0229760 [Patent Document 8] U.S. Patent No. 8,012,291 [Patent Document 9] U.S. Patent No. 8,308,101 Summary of the Invention [Problem to be solved by the invention]

[0016] In a system that may use a shear mechanism, there is a need to achieve a high shear angle with low risk of breaking the tow material and to allow easy adjustment for different installation operations.

[0017] The higher the shear stiffness of the tow material, the more difficult it is to implement an effective shear mechanism and the higher the risk of failure.

[0018] SUMMARY OF THE EMBODIMENTS Embodiments seek to alleviate one or more problems associated with the prior art. [Means for solving the problem]

[0019] Accordingly, one aspect of the invention provides a tape laying head configured to lay a tow material into a mold in building a composite structure, the tape laying head comprising a shear mechanism configured to receive tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material during steering of the tow material; and a tension control system configured to control the lateral component of the driving force acting on the tow material to be equal to or less than a maximum lateral friction force associated with the shear mechanism by varying and monitoring the tension applied to the tow material by the tension control system.

[0020] The tension control system may further include a first load sensor between the tow supply and the shear mechanism configured to generate a first load sensor signal representative of the tension in the tow material, the first load sensor signal may be used to monitor the drive force.

[0021] The tow material may include a backing material, and the shear mechanism may be configured to separate the tow material from the backing material, and the tension control system may further include a second load sensor configured to generate a second load sensor signal representative of the tension in the backing material between the shear mechanism and the backing material recovery section, and the second load sensor signal may be used to monitor the drive force.

[0022] The shearing mechanism may further include a tow guide roller and a gripping shoe or roller, and the tension control system may further include a first motor configured to drive rotation of the tow guide roller, and the tension may be applied at least in part by the first motor.

[0023] The tension control system may further include a second motor configured to drive operation of the backing material retriever, and the tension may be applied, at least in part, by the second motor.

[0024] The tension control system may further include a brake associated with the tape supply and configured to brake feeding of the tow material from the tape supply to the shear mechanism, and the tension may be applied at least in part by the brake.

[0025] The tension control system may be further configured to maintain the drive force above a minimum threshold by varying the tension.

[0026] The tow material may be a pre-impregnated tow material.

[0027] The shear mechanism may include a compression roller and a gripping shoe or roller, where a first shear boundary of the pair of shear boundaries is defined by a contact point between the compression roller and the mold in normal operation, and a second shear boundary of the pair of shear boundaries is defined by a contact point between the compression roller and the gripping shoe or roller.

[0028] The tape laying head may further include a web mechanism, the tow material comprising the web prior to shear deformation of the tow material, and the web mechanism may be configured to remove the web from the tow material after the tow material is laid down in the mold.

[0029] The web mechanism may be further configured to apply the web to the tow material prior to shear deformation of the tow material.

[0030] The web mechanism may include a supply of web material and a web material return associated with a motor, the motor configured to actuate the web material return to pull the web from the supply of web material.

[0031] The tape laying head may further include a tow material supply section and / or a backing material recovery section, and a slip compensation mechanism configured to move the shear mechanism laterally relative to the tow material supply section and / or the backing material recovery section so that lateral slippage of the tow material is compensated for.

[0032] The slip compensation mechanism may include one or more rails configured to enable movement of the shear mechanism or one or more of the tow guide roller and gripping shoe relative to a portion of the head, and a drive for driving movement of the shear mechanism or the tow guide roller and gripping shoe.

[0033] The slip compensation mechanism may further include a sensor configured to sense lateral slippage of the tow material.

[0034] Another aspect provides a tape laying system including a plurality of tape laying heads as described above.

[0035] Another aspect provides a controller for use in a tension control system of a tape laying system, the tape laying system including a shear mechanism configured to receive a tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material while steering the tow material, and the controller configured to control a lateral component of the driving force acting on the tow material to be equal to or less than a maximum lateral friction force associated with the shear mechanism by effecting a change in tension applied to the tow material and monitoring the driving force.

[0036] The controller may further be configured to receive a first load sensor signal representative of tension in the tow material between the tow supply and the shear mechanism, the first load sensor signal may be used by the controller to monitor the drive force.

[0037] The tow material may include a backing material, and the shear mechanism may be configured to separate the tow material from the backing material, and the controller may be further configured to receive a second load sensor signal representative of the tension in the backing material between the shear mechanism and the backing material recovery portion, and the second load sensor signal may be used by the controller to monitor the drive force.

[0038] The controller may be further configured to output a first motor signal, the shearing mechanism may further include a tow guide roller and a gripping shoe or roller, the first motor may drive rotation of the tow guide roller, the first motor signal may control operation of the first motor, and the tension may be applied at least in part by the first motor.

[0039] The controller may further be configured to output a second motor signal, the second motor may drive operation of the backing material recovery portion, the second motor signal may control operation of the second motor, and the tension may be applied, at least in part, by the second motor.

[0040] A brake may be associated with the tape supply and configured to brake the feeding of the tow material from the tape supply to the shear mechanism, the controller may be configured to generate a brake signal to control the brake, and the tension may be applied, at least in part, by the brake.

[0041] The controller may further be configured to maintain the drive force above a minimum threshold by varying the tension.

[0042] The tape laying system may further include a web mechanism, wherein the tow material comprises a web prior to shear deformation of the tow material, and the controller may further be configured to actuate the web mechanism and remove the web from the tow material after the tow material is laid down in the mold.

[0043] The controller may be further configured to actuate the webbing mechanism to apply the webbing to the tow material prior to shearing the tow material.

[0044] The web mechanism may include a supply of web material and a web material return associated with a motor, the controller being further configured to operate the motor to pull the web from the supply of web material.

[0045] The tape laying system may further include a tow material supply section and / or a backing material recovery section and a slippage compensation mechanism, and the controller may further be configured to operate the slippage compensation mechanism to move the shear mechanism laterally relative to the tow material supply section and / or the backing material recovery section, thereby compensating for lateral slippage of the tow material.

[0046] The slip compensation mechanism includes one or more rails configured to enable movement of one or more of the shear mechanism or the tow guide roller and the gripping shoe relative to a portion of the system, and a drive device, and the controller is configured to operate the drive device to drive movement of the shear mechanism or the tow guide roller and the gripping shoe.

[0047] The controller may be further configured to receive a signal from the sensor indicative of lateral slippage of the tow material.

[0048] Another aspect provides a control method for use in a tension control system of a tape laying system, the tape laying system including a shear mechanism configured to receive a tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, during steering of the tow material, the driving force having a longitudinal component and a lateral component with respect to the tow material, the method controlling a lateral component of the driving force acting on the tow material to be equal to or less than a maximum lateral friction force associated with the shear mechanism by effecting a variation in tension applied to the tow material and monitoring the driving force.

[0049] The control method may further include receiving a first load sensor signal representative of tension in the tow material between the tow supply and the shear mechanism, and using the first load sensor signal to monitor the drive force.

[0050] The tow material may include a backing material, and the shear mechanism may be configured to separate the tow material from the backing material, and the control method may further include receiving a second load sensor signal representative of tension in the backing material between the shear mechanism and the backing material recovery section, and using the second load sensor signal to monitor the drive force.

[0051] The control method may further include outputting a first motor signal, the shear mechanism may further include a tow guide roller and a gripping shoe or roller, the first motor may drive rotation of the tow guide roller, the first motor signal may control operation of the first motor, and the tension may be applied at least in part by the first motor.

[0052] The control method further includes outputting a second motor signal, the second motor may drive operation of the backing material recovery portion, the second motor signal may control operation of the second motor, and the tension may be applied at least in part by the second motor.

[0053] A brake may be associated with the tape supply and configured to brake the feeding of the tow material from the tape supply to the shear mechanism, the control method further including generating a brake signal for controlling the brake, and the tension may be applied at least in part by the brake.

[0054] The control method may further include maintaining the drive force above a minimum threshold by varying the tension.

[0055] The tape laying system further includes a web mechanism, and the tow material comprises a web prior to shear deformation of the tow material, and the method further includes actuating the web mechanism to remove the web from the tow material after the tow material is laid into the mold.

[0056] The method may further include actuating a web mechanism to apply a web to the tow material prior to shearing the tow material.

[0057] The web mechanism may include a supply of web material and a web material return associated with a motor, the method further including actuating the motor to pull the web from the supply of web material.

[0058] The tape laying system may further include a tow material supply section and / or a backing material recovery section and a slippage compensation mechanism, and the method may further include activating the slippage compensation mechanism to move the shear mechanism laterally relative to the tow material supply section and / or the backing material recovery section, thereby compensating for lateral slippage of the tow material.

[0059] The slip compensation mechanism may include one or more rails and a drive device configured to enable movement of one or more of the shear mechanism or the tow guide roller and the gripping shoe relative to a portion of the system, and the method further includes actuating the drive device to drive movement of the shear mechanism or the tow guide roller and the gripping shoe.

[0060] The method may further include receiving a signal from the sensor indicative of lateral slippage of the tow material.

[0061] Another aspect provides a computer readable medium having instructions stored thereon that, when executed, cause operation of the above-described control method.

[0062] Another aspect provides a tape laying head configured to lay a tow material into a mold in building a composite structure, the tape laying head including a shearing mechanism configured to receive a tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shearing mechanism, the shearing mechanism further configured to apply a driving force to the tow material, the driving force having longitudinal and lateral components to the tow material during steering of the tow material, the shearing mechanism including a compression roller and a gripping shoe or roller, a first shear boundary of the pair of shear boundaries being defined by a contact point of the compression roller and the mold in normal operation, and a second shear boundary of the pair of shear boundaries being defined by a contact point of the compression roller and the gripping shoe or roller.

[0063] Another aspect provides a tape laying head configured to lay a tow material into a mold in building a composite structure, the tape laying head including a shear mechanism configured to receive a tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a transverse component relative to the tow material during steering of the tow material; and a web mechanism, the tow material comprising a web prior to shear deformation of the tow material, the web mechanism configured to remove the web from the tow material after the tow material is laid into the mold.

[0064] The web mechanism may be further configured to apply the web to the tow material prior to shear deformation of the tow material.

[0065] The web mechanism includes a supply of web material and a web material return associated with a motor, the motor configured to actuate the web material return to pull the web from the supply of web material.

[0066] Another aspect provides a tape laying head configured to lay a tow material into a mold in constructing a composite structure, the tape laying head including a shear mechanism configured to receive tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material during steering of the tow material, a tow material supply and / or a backing material collector, and a slippage compensation mechanism configured to move the shear mechanism laterally relative to the tow material supply and / or the backing material collector, thereby compensating for lateral slippage of the tow material.

[0067] The slip compensation mechanism may include one or more rails configured to enable movement of one or more of the shear mechanism or the tow guide roller and the gripping shoe relative to a portion of the head, and a drive for driving the movement of the shear mechanism or the tow guide roller and the gripping shoe.

[0068] The slip compensation mechanism may further include a sensor configured to sense lateral slippage of the tow material.

[0069] Another aspect provides a tape laying system including a plurality of tape laying heads as described above.

[0070] Another aspect provides a controller for use in a tension control system of a tape laying system, the tape laying system including a shear mechanism configured to receive tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having longitudinal and transverse components relative to the tow material during steering of the tow material; and a web mechanism, the tow material comprising a web prior to shear deformation of the tow material; and a controller configured to actuate the web mechanism to remove the web from the tow material after the tow material is laid into the mold.

[0071] The controller may be further configured to actuate the webbing mechanism to apply the webbing to the tow material prior to shearing the tow material.

[0072] The web mechanism may include a supply of web material and a web material return associated with a motor, the controller being further configured to operate the motor to pull the web from the supply of web material.

[0073] Another aspect provides a controller for use in a tension control system of a tape laying system, the tape laying system including a shear mechanism configured to receive tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material during steering of the tow material, a tow material supply and / or a backing material recovery portion, and a slippage compensation mechanism, the controller configured to operate the slippage compensation mechanism to move the shear mechanism laterally relative to the tow material supply and / or the backing material recovery portion such that lateral slippage of the tow material is compensated for.

[0074] The slip compensation mechanism includes one or more rails configured to enable movement of one or more of the shear mechanism or the tow guide roller and the gripper shoe relative to a portion of the tape laying system, and a drive device, and the controller is configured to operate the drive device to drive movement of the shear mechanism or the tow guide roller and the gripper shoe.

[0075] The controller may be further configured to receive a signal from the sensor representative of lateral slippage of the tow material.

[0076] Another aspect provides a control method for use in a tension control system of a tape laying system, the tape laying system including a shear mechanism configured to receive tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a transverse component relative to the tow material during steering of the tow material, the tape laying system further including a web mechanism, the tow material comprising a web prior to shear deformation of the tow material, and the method including actuating the web mechanism to remove the web from the tow material after the tow material is laid into the mold.

[0077] The method may further include actuating a web mechanism to apply a web to the tow material prior to shearing the tow material.

[0078] The web mechanism may include a supply of web material and a web material return associated with a motor, the method further including actuating the motor to pull the web from the supply of web material.

[0079] Another aspect provides a control method for use in a tension control system of a tape laying system, the tape laying system including a shear mechanism configured to receive tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material during steering of the tow material, the tape laying system further including a web mechanism, a tow material supply and / or a backing material return, and a slippage compensation mechanism, the method including actuating the slippage compensation mechanism to move the shear mechanism laterally relative to the tow material supply and / or the backing material return such that lateral slippage of the tow material is compensated for.

[0080] The slip compensation mechanism may include one or more rails and a drive configured to enable movement of one or more of the shear mechanism or the tow guide roller and the gripper shoe relative to a portion of the tape laying system, and the method further includes actuating the drive to drive movement of the shear mechanism or the tow guide roller and the gripper shoe.

[0081] The method may further include receiving a signal from the sensor representative of a lateral slippage of the tow material.

[0082] Another aspect provides a computer readable medium having instructions stored thereon that, when executed, cause operation of the above-described control method.

[0083] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0084] [Figure 1] FIG. 1 is a schematic diagram of a tension control system of some embodiments. [Diagram 2] FIG. 1 is a schematic diagram of a tape laying system of some embodiments. [Diagram 3]FIG. 2 is a schematic diagram of a tape laying head of some embodiments. [Figure 4] FIG. 1 is a schematic illustration of shear between and within a tow material. [Diagram 5] FIG. 1 is a schematic diagram of the participation of the shear mechanism, with force vectors. [Figure 6] FIG. 1 is a schematic diagram of the participation of the shear mechanism, with force vectors. [Figure 7] FIG. 1 is a schematic diagram of the participation of the shear mechanism, with force vectors. [Figure 8] FIG. 1 is a schematic diagram of the participation of the shear mechanism, with force vectors. [Figure 9] FIG. 1 illustrates a control configuration that may be used by some embodiment tension control systems. [Figure 10] FIG. 2 is a schematic diagram of a tape supply of some embodiments. [Figure 11] FIG. 2 is a schematic diagram of a backing material recovery section of some embodiments. [Figure 12] FIG. 2 is a schematic diagram of a tape laying head of some embodiments. [Figure 13] FIG. 2 illustrates a compression roller and gripper shoe of some embodiments. [Figure 14] FIG. 2 illustrates a compression roller and gripper shoe of some embodiments. [Figure 15] FIG. 2 illustrates a compression roller and gripper shoe of some embodiments. [Figure 16] FIG. 2 is a schematic diagram of a tape laying head of some embodiments. [Figure 17] FIG. 2 is a schematic diagram of a tape laying head of some embodiments with a testing fixture. [Figure 18] FIG. 2 is a schematic diagram of a tape laying head of some embodiments in which the creel unit is identified. [Figure 19] FIG. 2 is a schematic diagram of a tape laying head of some embodiments with a slip compensation mechanism. [Figure 20] FIG. 2 is a schematic diagram of a tape laying head of some embodiments with a slip compensation mechanism. [Figure 21]FIG. 2 is a schematic diagram of a tape laying head of some embodiments with a slip compensation mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0085] The embodiment includes a tape laying head 1 (see, e.g., FIGS. 2 and 3 ). The tape laying head 1 is configured to lay a tape 2 onto a mold 3. The tape laying head 1 may be part of a tape laying system 100, and some embodiments include a tape laying system 100, which may include multiple tape laying heads 1, for example, as described herein.

[0086] The tape laying head 1 may be configured to lay down a tape 2 onto a mould 3, for example as part of building a composite structure.

[0087] The tape laying system 100 is configured to move the, or each, tape laying head 1 across the mold 3, for example using a robotic arm or gantry. The, or each, tape laying head 1 is configured to lay the tape 2 onto the mold 3 as the mold 3 is traversed by the, or each, tape laying head 1. In some embodiments, the tape laying system 100 is configured to move the, or each, tape laying head 1 across a substantially stationary mold 3, but equally the tape laying system 100 may be configured to move the mold 3 (or to move both the mold 3 and the, or each, tape laying head 1) relative to the substantially stationary tape laying head 1 or 1. In any case, however the tape laying system 100 may be configured to move the, or each, tape laying head 1 relative to the mold 3, this may be accomplished.

[0088] The tape laying head 1 is configured to receive tape 2 from a tape supply 4 for laying onto a mold 3. The tape supply 4 may, for example, form part of the tape laying head 1 and may also be part of a wider tape laying system 100.

[0089] The tape 2 from the tape supply 4 is configured to be delivered by the tape laying head 1 to the shearing mechanism 5. The shearing mechanism 5 is configured to receive the tape 2 from the tape supply 4 and lay the tape 2 onto the mold 3.

[0090] In some embodiments, the tape 2 provided by the tape supply may have a backing 21 and a tow material 22, with the backing 21 supporting the tow material 22 (e.g., as the tape 2 is fed from the tape supply 4 to or toward the shearing mechanism 5). For example, the tow material 22 may be laid down in the mold 3 and the backing 21 may be for disposal. The tow material 22 may include one or more reinforcing fibers, as described in more detail herein. In some embodiments, the backing 21 provides a binder or resin material that may be bonded with the one or more reinforcing fibers to form the tow material 22. The binder or resin material may be provided, for example, as a layer on the backing 21.

[0091] At or in the area of ​​the shearing mechanism 5, the backing material 21 may be removed from the tow material 22. This may occur before the tow material is laid down on the mold 3 or as the tow material is laid down on the mold 3. A heater (not shown) may be provided to heat the tow material 22, and in particular the binder material or resin material. The heater may be provided, for example, in the path of the tow material 22 upstream of the shearing mechanism 5.

[0092] The tow laying head 1 may be configured to deliver the backing material 21, once separated from the tow material 22, to a backing material recovery section 6. The backing material recovery section 6 may be configured to recover the backing material 21 for later disposal (which may include, for example, recycling). The backing material recovery section 6 may, for example, form part of the tape laying head 1 or may be part of the wider tape laying system 100.

[0093] Thus, in operation, the tape 2 may pass from the tape supply 4 to the shear mechanism 5 (see solid arrows in FIG. 1 , which represent the direction of travel of the tape 2 and / or the backing 21). At or within the area of ​​the shear mechanism 5, the backing 21 of the tape 2 may be separated from the tow material 22. The shear mechanism 5 may convey the tow material 22 to the mold 3 (the dashed arrows in FIG. 3 indicate the direction of travel of the shear mechanism 5 relative to the mold 3), and the backing 21 may be fed to the backing recovery section 6 for recovery. All or some of these operations may be performed as part of the operation of the tape laying head 1, but as will be explained, some parts (such as the tape supply 4 and / or the backing recovery section 6) may be part of the wide tape laying system 100, and thus the feeding and / or recovery operations may be performed by the wide tape laying system 100, as the case may be.

[0094] The embodiment includes a tension control system 7 (see, e.g., FIGS. 1 and 3 ). The tension control system 7 is configured to control the tension of the tow material 22 at a stage immediately prior to the laying of the tow material into the mold 3. In other words, the tension control system 7 may be configured to control the tension of the tow material 22 in the shear mechanism 5.

[0095] tape The tape 2 as described includes a backing 21 and a tow material 22. The backing 21 can be, for example, a paper-based backing 21. The backing 21 can be configured to support the tow material 22, for example, prior to laying the tow material 22 onto the mold 3. The backing 21 can also be configured to aid in storage of the tape 2, such that the tape 2 can be wound onto a bobbin 41 (e.g., tape supply 4, see FIG. 10 ).

[0096] The tow material 22 includes one or more reinforcing fibers 22a (see, e.g., FIG. 4), which could be, for example, carbon fiber or glass fiber, although this could take many different forms. The reinforcing fibers 22a can be elongated fibers and can be in a woven or non-woven configuration within the tow material 22. The reinforcing fibers 22a, if multiple, can be arranged in one or more bundles, known as tows 22b.

[0097] The tow material 22 may include a binder material. The binder material may be configured, for example, to help maintain the relative arrangement of the reinforcing fibers 22a relative to one another and / or to help attach the tow material 22 to the mold 3 (or to other layers of the tow material 22 already laid down in the mold 3). The binder material may be insufficient as a resin material for use in forming a composite structure from the tow material 22. Thus, the tow material 22 may be impregnated and / or intended to be impregnated with a thermosetting resin material, for example, after the tow material 22 is laid down in the mold 3. Such a tow material 22 may be described as a dry tow material 22 due to the absence of a suitable resin material in its supplied form.

[0098] The tow material 22 may be a pre-impregnated tow material 22. The pre-impregnated tow material 22, in its supplied form, includes a suitable resin material (i.e., a thermosetting resin material) to form a composite structure from the tow material 22. Thus, for example, no additional thermosetting resin material needs to be applied. Thus, the pre-impregnated tow material 22 includes one or more reinforcing fibers 22a and a resin material. The resin material may also be referred to as a matrix material and could take other forms.

[0099] Pre-impregnated tow material 22 tends to have a higher shear stiffness than dry tow material 22 .

[0100] In some embodiments, the tow material 22 is provided in two parts: one or more reinforcing fibers and a binder or resin material. The two parts may be combined, for example, in the tape laying head 1 or in the wide tape laying system 100. The binder or resin material may be provided, for example, on a backing material 21.

[0101] In some embodiments, an endless backing 21 may be provided (as part of the tape laying head 1) that serves a similar purpose as the backing 21 described herein with respect to supporting the tow material 22 (but not related to storing the tow material 22 or providing a binder or resin material). Thus, in such embodiments, the tow material 22 may be provided to the endless backing 21 from a tape supply 4 within the tape laying head 1. In these embodiments, references to tape 2 with respect to the tape supply 4 are references to the tow material 22 (e.g., the tow material 22 may be provided on a bobbin 41, etc.).

[0102] Although the embodiment is described with respect to the tape 2 including a backing 21 in its supplied form, it should be understood that the same applies to embodiments in which the backing 21 is in the form of an endless backing 21 provided in the tape laying head 1, or in which the tow material 22 is added to the resin material in the tape laying head 1 or in the wider tape laying system 100.

[0103] Generally, as used herein, a reference to tape 2 may be interpreted as a reference to one or more tows, each of which may include one or more reinforcing fibers 22a. Thus, a reference to tape 2 may be a reference to a tow, and the term is not used in any particular sense herein unless otherwise explained.

[0104] Tape Supply The tape supply 4 may include a bobbin 41 on which the tape 2 is wound. The tape supply 4 may include a creel 42 (see, e.g., FIG. 10 ), which may be configured to receive and support the bobbin 41. In some embodiments, there are multiple bobbins 41, with each bobbin 41 being received and supported by a creel 42.

[0105] As will be described, the tape supply 4 may form part of the tape laying head 1 or part of the wider tape laying system 100.

[0106] The tape supply 4 may be configured to supply the tape 2 to the shearing mechanism 5, and as such, a tape path may be defined between the tape supply and the shearing mechanism 5. This tape path may be formed, at least in part, by the tape laying head 1. One or more portions of this tape path may be defined, for example, by a tube through which the tape 2 may pass.

[0107] In some embodiments, the tape supply 4 is configured to supply tape 2 to multiple tape laying heads 1 of the tape laying system 100 (e.g., in embodiments where there are multiple tape laying heads 1 as part of the tape laying system 100). Thus, the tape supply 4 may include at least one bobbin 41 for each tape laying head 1, such that a separate tape (or tow) 2 may be supplied to each tape laying head 1. In some embodiments, one or more tapes (or tows) 2 are supplied in parallel to a single (i.e., one and only one) tape laying head 1 (and there may be multiple such tape laying heads 1, each receiving multiple tapes 2 in parallel from the tape supply 4).

[0108] The or each bobbin 41 may be removable, and the tape supply 4 may include a creel 42 configured to receive one or more bobbins 41. The tape supply 4 may at least partially define one or more tape paths configured to pass the tape 2 toward the shearing mechanism 5 (or, in some cases, multiple mechanisms 5).

[0109] The tape 2 supplied by the tape supply 4 can be any tape 2 described herein. Thus, in some embodiments, the tape 2 can include a tow material 22 and a backing material 21. In some embodiments, the tape 2 supplied by the tape supply 4 includes a tow material 22, but the backing material 21 is provided separately, for example, as an endless loop. The tow supply 4 can be configured to pass the tow material 22 to the backing material 21 (e.g., an endless loop), in some such embodiments. In some embodiments, the endless loop can be considered to be part of the tape supply 4. In some embodiments, the endless loop can be part of the tape laying head 1, for example.

[0110] shear mechanism The shearing mechanism 5 may generally be a mechanism as described in US Pat. No. 5,399,633.

[0111] The shearing mechanism 5 may include a compression shoe 51 configured to press the tow material 22 onto the mold 3 (it will be understood that in this specification references to laying material, such as the tow material 22, onto the mold 3 include indirect laying of material onto the mold 3 (e.g., laying of material onto a layer of material already laid onto the mold 3).

[0112] The compression shoe 51 may have a first side 51a opposite a second side 51b across the width of the compression shoe 51. The first side 51a may have a generally flat or planar surface as shown, or may have a surface of a different configuration. At the base of the first side 51a (which may also be the base of the compression shoe 51) there may be a substantially straight trailing edge of the compression shoe 51. The trailing edge bounds the first side 51a of the compression shoe 51 and a compression side 51c of the compression shoe 51. The compression side 51c includes a compression surface 51c, the terms being used interchangeably herein.

[0113] The compression surface 51c is configured to press the tow material 22 against the mold 3. The compression surface 51c may be configured to allow the tow material 22 to pass between the compression shoe 51 and the mold 3 as the compression shoe 51 (and, for example, the tape laying head 1) moves across the mold 3 to lay down the tow material 22. The compression surface 51c may be a substantially smooth surface and may have a relatively low coefficient of friction to allow the compression shoe 51 to slide over the laid down tow material 22.

[0114] The trailing edge of the compression shoe 51 represents the final portion of the compression shoe 51 that presses the tow material 22 against the mold 3 as the compression shoe 51 moves relative to the mold 3 during normal laying operations. It will therefore also be referred to as the trailing edge of the compression shoe 51, or more specifically, the trailing edge of the compression surface 51c (rear (and front) being defined by the direction of movement of the compression shoe 51 relative to the mold 3).

[0115] The compression shoe 51 may also include a leading edge. The leading edge may be opposite the trailing edge across the width of the compression shoe 51 (and the width may be at the base of the compression shoe 51). The leading edge may define a boundary between the second side 51b of the compression shoe 51 and the compression side 51c of the compression shoe 51.

[0116] The leading edge of the compression shoe 51 represents the first portion of the compression shoe 51 that presses the tow material 22 against the mold 3 as the compression shoe 51 moves relative to the mold 3 during normal laying operations (this may be the shear boundary described herein). Accordingly, this will be referred to as the leading edge of the compression shoe 51, or more specifically, the leading edge of the compression surface 51c (again, front (and rear) is defined by the direction of movement of the compression shoe 51 relative to the mold 3).

[0117] In some embodiments, the trailing edge may be a relatively sharp edge in that the first side 51a may meet the compression side 51c along a thinned edge (i.e., with a relatively small radius.) In some embodiments, the leading edge may be a relatively rounded edge in that the second side 51b may meet the compression side 51c along a curved edge (in cross section) having a relatively large radius (compared to the thinned portion above).

[0118] The trailing edge and the leading edge may both be substantially straight edges. In other words, the two edges may each extend along a substantially straight axis. The leading edge and the trailing edge may be substantially parallel to each other (i.e. the substantially straight axes may be substantially parallel to each other).

[0119] The second side 51b could have a curved surface, for example as shown, or could have a surface of a different configuration, in some embodiments, the second side 51b could have both generally flat and generally curved portions, for example as shown.

[0120] The second side 51b may be configured (e.g., shaped and sized) to at least partially receive the tow guide roller 52. Thus, the tow guide roller 52 may be part of the shearing mechanism 51 and may be disposed adjacent to the compression shoe 51. In particular, the tow guide roller 52 may be disposed adjacent to the second side 51b of the compression shoe 51.

[0121] The tow guide rollers 52 may be positioned such that the tow material 22 may pass through a portion of the tow guide rollers 52 adjacent the compression shoe 51 before the tow material 22 reaches the compression shoe 51. In other words, the tow guide rollers 52 may be positioned upstream of the compression shoe 51 with respect to the path of the tow material 22 through the shear mechanism 5.

[0122] It should be understood that the tow material 22 has a path of movement from the tape supply 4 to the shear mechanism 5, which path is formed from various portions through the tape laying head 1. The tow material path may in places be the same as the tape path, and the terms may be synonymous. Typically, however, the tape path is a reference to the path of the tape 2 (i.e., the path of the tow material 22 and, if provided, the backing 21), while the tow material path may or may not be the path for the backing. The path (tow material or tape), as the case may be, has an upstream and downstream direction, defined by the normal direction of travel of the tow material 22 or tape 2 during the laying operation, i.e., generally from the tape supply 4 towards the shear mechanism 5 (particularly towards the compression shoe 51).

[0123] The tow guide roller 52 may be configured to rotate about an axis that is generally parallel to the leading edge of the compression shoe 51. The tow guide roller 52, in some embodiments, may have an outer surface made from silicone.

[0124] The shearing mechanism 5 may include a gripper shoe 53 (which may also be referred to, for example, as a tow feed shoe). The gripper shoe 53 may be disposed adjacent to the tow guide roller 52, and the tow material may pass between the gripper shoe 53 and the tow guide roller 52. In other words, at least a portion of the tow material path (and, in some cases, the tape path) may be defined between the tow guide roller 52 and the gripper shoe 53.

[0125] The gripping shoe 53 may be formed from a generally elongated member pivotally mounted to the tow guide roller 52, and the distance between at least a portion of the gripping shoe 53 and at least a portion of the tow guide roller 52 may be varied by rotation of the gripping shoe 53 about its pivotable mount 53a (which may form part of the shear mechanism 5). As shown, for example, the gripping shoe 53 may have a distal end adjacent the tow guide roller 52 and a proximal end (opposite the distal end). The pivotable mount 53a may be disposed between the proximal and distal ends of the gripping shoe 53.

[0126] The distal end of the gripping shoe 53 may be shaped to increase the surface area over which the tow material 22 (or tape 2) may be sandwiched between the tow guide roller 52 and the gripping shoe 53. Thus, the distal end of the gripping shoe 53 may be curved, and the degree of curvature may generally correspond to the circumferential shape of at least a portion of the tow guide roller 52.

[0127] Rotational movement of the gripping shoe 53 about the pivotable mount 53a can vary the distance between at least a portion of the gripping shoe 53 (e.g., a portion of its distal end) and the tow guide roller 52. Rotational movement of the gripping shoe 53 about the pivotable mount 53a can vary the force applied to the tow material 22 or tape 2 between at least a portion of the gripping shoe 53 (e.g., a portion of its distal end) and the tow guide roller 52 (this force can be a compressive force, or in other words, a gripping or clamping force).

[0128] The gripping shoe 53 may include a resilient biasing device 54, such as a spring, which may be a spiral wound spring, configured to bias the distal end of the gripping shoe 53 toward the guide roller 52. In some embodiments, the resilient biasing device 54 includes a pneumatic or hydraulic ram.

[0129] Thus, the tow material 22 may follow a tow material path (in the gripping area) between the tow guide roller 52 and the gripping shoe 53 before passing to the compression shoe 51, which may press the tow material 22 onto the mold 3 (i.e., lay the tow material 22 onto the mold 3) in the compression area.

[0130] In some embodiments, the tow material 22 may carry the backing 21 through the path between the tow guide roller 52 and the gripping shoe 53 (i.e., in the gripping area). As such, this portion of the path may similarly be described as a tape path. As the tape 2 leaves the path defined between the tow guide roller 52 and the gripping shoe 53, the backing 21 may be removed from the tow material 22. In other words, as the tape 2 leaves the gripping area, the backing 21 may be separated from the tow material 22. In some embodiments (such as those shown), the backing 21 may pass around the distal-most end of the gripping shoe 53.

[0131] The distal most end of the gripping shoe 53 may be the very end portion of its distal end. The distal most end of the gripping shoe 53 may be sized and / or shaped (e.g., may have an appropriate radius) to aid in the separation of the backing material 21 from the tow material 22.

[0132] The backing 21 may therefore follow a backing path from the gripper shoe 53. This path may extend up to or towards a backing recovery station 6, which may be downstream of the shear mechanism 5 (with respect to the path and normal direction of travel of the backing 21).

[0133] The last portion of the gripping shoe 53 that the tow material 22 contacts (on its way towards the compression shoe 51) may in some embodiments be a straight portion of the gripping shoe 53 that may be referred to as the gripping edge and extend parallel to the leading edge of the compression shoe 51, which edge may be a shear boundary as described herein.

[0134] As can be appreciated, the shear mechanism 5 can be configured to move in a first direction relative to the mold 3. The first direction can be, for example, a laying direction, which in the illustrated example of FIG.

[0135] The shearing mechanism 5 may further be configured to move in a second direction relative to the mold 3, the second direction being generally perpendicular to the first direction (e.g., into or out of the page in the illustrated example of FIG. 3). This second direction may be a shear direction, intended to subject the tow material 22 to a shear deformation. As will be appreciated, this second direction may be a direction parallel to the trailing edge, leading edge, and / or the axis of rotation of the tow guide roller 52.

[0136] The movement of the shear mechanism 5 in the first direction may be driven by the tape laying head 1 moving in the first direction relative to the mold 3. The movement of the tape laying head 1 in the first direction relative to the mold 3 may be driven by the movement (relative to the mold 3) of a part of the tape laying system 100 to which the tape laying head 1 is attached. The tape laying system 100 may for this purpose include a gantry to which the tape laying head 1 is attached (the same gantry may have multiple tape laying heads 1 attached to it).

[0137] The movement of the shearing mechanism 5 in the second direction may be driven by the tape laying head 1 moving in the second direction relative to the mold 3. The movement of the tape laying head 1 in the second direction relative to the mold 3 may be driven by the movement (relative to the mold 3) of a part of the tape laying system 100 (such as a gantry) to which the tape laying head 1 is attached. In some embodiments, the movement of the shearing mechanism 5 in the second direction may be a driven movement of the shearing mechanism 5 relative to the tape laying head 1 in the second direction.

[0138] Thus, the shear mechanism 5 may be configured to provide shear deformation of the tow material 22, which may be referred to as, for example, tow steering, or shear tow steering. In some embodiments, the shear mechanism 5 may take different forms. For example, the compression shoe 51 may be in the form of a roller. Similarly, the gripper shoe 53 may also be in the form of a roller, for example. In either case, the shear mechanism 5 may provide a pair of shear boundaries.

[0139] Backing material recovery section The backing material recovery section 6 may, for example, with reference to Fig. 11, include a bobbin 61 (to distinguish this bobbin 61 from the bobbin 41, the bobbin 61 may be referred to as a recovery bobbin 61, and the other bobbin 41 may be referred to as, for example, a supply bobbin 41). The recovery bobbin 61 may be configured to receive and recover the backing material 21 following separation from the tow material 22. In other words, during operation of the tape laying head 1 and / or the system 100, used backing material 21 may be wound onto the recovery bobbin 61.

[0140] The backing material collector 6 may include a creel 62, which may be configured to receive and support a collector bobbin 61. In some embodiments, there are multiple collector bobbins 61, with each collector bobbin 61 being received and supported by a creel 62. The creel 62 may be a separate creel 62 from that of the tape supply 4, and thus may be referred to as the collector creel 62 (the other creel 42 being referred to as the supply creel 42). However, in some embodiments, a creel is shared such that the supply creel 42 and the collector creel 62 are the same creel (i.e., the same creel construction).

[0141] As will be explained, the backing material collector 6 may form part of the tape laying head 1 or part of the wide tape laying system 100.

[0142] The backing material collector 6 may be configured to receive the backing material 21 from the shearing mechanism 5, and as such, a backing material path may be defined between the shearing mechanism 5 and the backing material collector 6. This backing material path may be formed, at least in part, by the tape laying head. One or more portions of this backing material path may be defined, for example, by a tube through which the backing material 21 may pass.

[0143] In some embodiments, the backing material collector 6 is configured to receive the backing material 21 from multiple tape laying heads 1 of the tape laying system 100 (e.g., in some embodiments where there are multiple tape laying heads 1 as part of the tape laying system 100). Thus, the backing material collector 6 may include at least one bobbin 61 for each tape laying head 1, and a separate backing material 21 may be received from each tape laying head 1. In some embodiments, one or more strips of backing material 21 are received in parallel from a single (i.e., one and only one) tape laying head 1 (and there may be multiple such tape laying heads 1, each providing multiple strips of backing material 21 in parallel to the backing material collector 6).

[0144] The or each bobbin 61 may be removable, and the backing material collector 6 may include a creel 62 configured to receive one or more bobbins 61. The backing material collector 6 may at least partially define one or more backing material paths along which the backing material 21 is configured to pass towards the backing material collector 6 (or, as the case may be, multiple collectors 6).

[0145] In embodiments in which the backing material 21 is an endless loop, the path of the backing material may pass from the shearing mechanism 5 to the backing material recovery section 6 and then back to the shearing mechanism 5 (where it may pass between the tow guide roller 52 and the gripping shoe 53, as described with respect to the embodiments in which the backing material 21 is part of the tape 2 and is not an endless loop).

[0146] Tension Control System It has been found that controlling the tension of the tow material 22 in the shear mechanism 5 is important to promote more ideal shear deformation of the tow material 22. In particular, controlling the tension of the tow material 22 between the gripping area and the pressing area (which may be between the gripping edge of the gripping shoe 53 and the leading edge of the compression shoe 51, i.e., between the shear boundary) is important.

[0147] As will be explained, the tow material 22 can include one or more reinforcing fibers 22a. For purposes of explanation, an embodiment will be considered in which the tow material 22 includes a plurality of reinforcing fibers 22a, at least some of which are arranged in parallel, for example, along the length of the tow material 22 (which length generally follows the path of the tow material).

[0148] Ideally, the shear deformation applied by use of the shear mechanism 5 results in shear deformation in all of the reinforcing fibers 22a across the width of the tow material 22--intra-tow shear deformation (see FIG. 4). This shear deformation would ideally be substantially uniform. This requires sliding of the reinforcing fibers 22a within the tow material 22 relative to one another.

[0149] In practice, however, such slippage does not readily occur uniformly between the reinforcing fibers of the tow material 22, resulting in inter-tow shear (see FIG. 4). This results in localized buckling or wrinkling (or other defects) that will typically occur adjacent to the boundaries of shear deformation (which are defined by the gripped and pressed regions, i.e., shear boundaries, as described herein).

[0150] Additionally, slippage can result in the laid tow material 22 becoming misaligned with the intended laid tow material path on the mold 3 .

[0151] It has been discovered that controlling the tension of the tow material 22 between the compression and gripping regions (i.e., between the shear boundaries) can reduce the risk of such defects occurring. In particular, applying tension while shearing the tow material 22 forces the tow material 22 to deform in intra-tow shear, which is the preferred mode of shear deformation (the mode for providing optimal quality).

[0152] Accordingly, the embodiment includes a tension control system 7 configured to control this tension during operation of the tape laying head 1 .

[0153] The tension control system 7 may include a first load sensor 71 and a second load sensor 72 (see FIGS. 1 and 3). The first and second load sensors 71, 72 are communicatively connected to a controller 73 of the tension control system 7.

[0154] The controller 73 may include one or more processors 73 a, memory 73 b, computer-readable media 73 c, and input / output interfaces 73 d, all of which may be communicatively coupled together to form the controller 73.

[0155] The first and second load sensors 71 may be communicatively connected to an input / output interface 73d of the controller 73. Thus, the controller 73 may be configured to receive a first load sensor signal from the first load sensor 71 and a second load sensor signal from the second load sensor 72. These signals may be received, for example, at the input / output interface 73d.

[0156] The first load sensor signal may be a signal indicative of a load detected by the first load sensor 71. The second load sensor signal may be a signal indicative of a load detected by the second load sensor 72.

[0157] The first load sensor 71 may be configured to sense the tension in the tow material 22 upstream of the shear mechanism 5 in the tow material path. Thus, the first load sensor signal may be a signal indicative of the tension in the tow material 22 between the tape supply 4 and the shear mechanism 5. As will be understood from the description herein, this tension in the tow material 22 may be the tension in the tape 2 (e.g., including the tow material 22 and the backing material 21).

[0158] The second load sensor 72 may be configured to sense the tension in the backing material 71 in the backing material path downstream of the shear mechanism 5. Thus, the second load sensor signal may be a signal indicative of the tension in the backing material 21 between the shear mechanism 5 and the backing material collector 6.

[0159] In other words, the first and second load sensor signals indicate tensions in the tow material 22 and backing material 21, respectively, with respect to the path of those materials, on either side of the shear mechanism 51. These may similarly be considered as an input tension (relative to the tension indicated by the first load sensor signal) and an output tension (relative to the tension indicated by the second load sensor signal).

[0160] The first and second load sensors 71, 72 can take many different forms. In some embodiments, each of the first and second load sensors 71, 72 includes a pair of follower rollers 71a, 72a, respectively. Thus, there may be a first pair of follower rollers 71a for the first load sensor 71. There may be a second pair of follower rollers 72a for the second load sensor 72.

[0161] Each follower roller of the first pair of follower rollers 71 a may be configured to rotate about a respective axis that may be generally parallel to one another and perpendicular to the direction of travel of the tow material 22 .

[0162] Each follower roller of the second pair of follower rollers 72a may be configured to rotate about a respective axis that may be generally parallel to one another and perpendicular to the direction of travel of the backing material 21.

[0163] The first follower roller pair 71a may be disposed on one side of the tow material 22 (which may be tape 2). The first load sensor 71 may include a first load cell 71b, which may be offset from the first follower roller pair 71a and disposed on the other side of the tow material 22 relative to the first follower roller pair 71a. The tow material path may pass at least partially around one of the rollers of the first follower roller pair 71a, around the first load cell 71b, and then at least partially around the other of the rollers of the first follower roller pair 71a.

[0164] The first load cell 71b may be in the form of a roller attached to an axle, with a load cell member associated with the axle, for example, to measure the force on the axle.

[0165] The second follower roller pair 72a may be located on one side of the backing 21. The second load sensor 72 may include a second load cell 72b which may be offset from the second follower roller pair 72a and located on the other side of the backing 21 relative to the second follower roller pair 72a. The backing path may pass at least partially around one of the rollers of the second follower roller pair 72a, around the second load cell 72b, and then at least partially around the other of the rollers of the second follower roller pair 72a.

[0166] The second load cell 72b may be in the form of a roller mounted on an axle, with a load cell member associated with the axle, for example, to measure the force on the axle.

[0167] The tension control system 7 may include a first motor 74 associated with the backing material recovery section 6 , a second motor 75 associated with the shear mechanism 5 , and a brake 76 associated with the tape supply section 4 .

[0168] The first motor 74 may be configured to drive the rotation of the collection bobbin 61. This may be achieved, for example, by driving (directly or indirectly) the rotation of at least a portion of the creel 62 to which the collection bobbin 61 may be or is attached. An indirect drive may include, for example, one or more gears.

[0169] The first motor 74 may be communicatively connected to the controller 73, and thus to the input / output interface 73d. The first motor 74 may be configured to receive a first motor control signal from the controller 73 via the communicative connection. The first motor control signal may control the operation of the first motor 74.

[0170] The second motor 75 may be configured to drive the rotation of the tow guide roller 52. This may be accomplished, for example, by driving (directly or indirectly) the rotation of a spindle to which the tow guide roller 52 is attached (a spindle that is part of the shear mechanism 5). An indirect drive may include, for example, one or more gears.

[0171] The second motor 75 may be communicatively connected to the controller 73, and thus to the input / output interface 73d. The second motor 75 may be configured to receive a second motor control signal from the controller 73 via the communicative connection. The second motor control signal may control the operation of the second motor 75.

[0172] In some embodiments, there is no motor associated with the tape supply 4 (or there is no motor configured to drive rotation of the tape supply 4 in feeding the tow material 22 or tape 2). The tape supply 4 may be considered to be passively actuated in such embodiments, since the tape 2 or tow material 22 may be drawn from the tape supply 4 by other parts of the tape laying head 1 (e.g., such as via actuation of the first and / or second motors 74, 75, etc.).

[0173] The brake 76 may be configured to apply a braking force, such as a braking torque, to the tape supply 4, i.e., to brake or otherwise slow the supply of tow material 22 or tape 2 from the tape supply 4. For example, the brake 76 may be configured to apply a braking force to the supply bobbin 41 to vary the rotational speed of the supply bobbin 41. To accomplish this, the brake 76 may be associated with the supply bobbin 41 and / or the creel 42 to which the supply bobbin 41 is attached and / or can be attached.

[0174] Brake 76 could take a number of different forms. Brake 76 may be electronically actuated and therefore may be communicatively coupled to controller 73 and configured to receive a brake signal from controller 73. Brake 76 may therefore be communicatively coupled to input / output interface 73d.

[0175] Brake 76 may be configured to apply a varying braking force under control of a brake signal, such that the braking torque applied to tape supply 4 (e.g., creel 42 and / or bobbin 41) may vary in response to the brake signal.

[0176] In some embodiments, the brake 76 is in the form of a magnetic brake. Thus, a portion of the tape supply 4 (e.g., a portion of the bobbin 41 or the creel 42) that rotates as the tape 2 is fed therefrom may carry at least one first magnet, which may be a permanent magnet. The first magnet may form part of the brake 76. The brake 76 may include a second magnet, which may be an electromagnet. The second magnet may be disposed within and associated with the magnetic field of the first magnet. The second magnet may be fixed against movement with the first magnet. In other words, the second magnet may be a substantially fixed magnet. The brake signal may be configured to vary the magnetic field generated by the second magnet relative to the first magnet to apply or release a braking force. The brake 76 may be, for example, a motor (which may be configured to only provide a braking force, but not drive the supply of tow material 22 from the tape supply 4). As will be appreciated, different configurations of magnetic brakes are possible, including embodiments in which the second magnet and the first magnet physically move relative to one another depending on a brake signal to vary the braking force. Other forms of brakes are possible, including, for example, mechanical brakes in which a brake disc coupled for rotation with the bobbin 41 or creel 42 is selectively gripped between brake pads to apply a braking force (a gripping force that is varied depending on a brake signal). Other forms of friction brakes are also envisioned for the brake 76.

[0177] Thus, the controller 73 may be configured to receive the first and second load sensor signals. The controller 73 may be configured to output first and second motor control signals and a brake signal.

[0178] The or each processor 73a may be configured to execute instructions, which may be stored on a computer-readable medium 73c. ​​Execution of these instructions may result in the performance of one or more tension control operations in relation to the tape laying head, as described herein. These tension control operations may include controlling the operation of the first motor 74, the second motor 75, and / or the brake 76.

[0179] The or each processor 73a may be communicatively connected to a memory 73b, and the or each processor 73a may use the memory 73b in executing instructions. The memory 73b may be, for example, a volatile memory.

[0180] The controller 73 may also be a shared controller configured to control the tape laying head 1 and / or one or more other operations of the wide tape laying system 100. This may include, for example, movement of the shear mechanism 5 relative to the mold 3 (which may include, for example, movement of the tape laying head 1 relative to the mold 3).

[0181] The controller 73 may be configured to receive one or more operating parameters. The or each operating parameter may be received from other parts of the tape laying head 1 and / or from the tape laying system 100.

[0182] The one or more operating parameters may include, for example, a set point for the tension of the tow material 22 (i.e., the desired tow material tension 22 in the shear mechanism 51 (e.g., between the compression shoe 51 and the gripping shoe 53)), and / or a shear angle for the tow material 22 (i.e., the shear angle for the tow material 22 laid on the mold 3 as described herein), which are parameters that characterize the operation of the tape laying head 1, and / or a movement speed of the tape laying head 1 relative to the mold 3.

[0183] One or more operating parameters may be received via input / output interface 73d and provided to the processor or each processor 73a and / or stored in memory 73b and / or stored in computer-readable medium 73c.

[0184] The controller 73 may be configured to use the or each received operating parameter in performing the or each tension control operation.

[0185] Tension Control If the tow material 22 is laid down on the mold 3 in a straight line using a conventional tape laying apparatus, the apparatus resistance force T is the sum of all forces (e.g., friction forces) acting on the tow material as it passes through a conventional tape laying head. l These forces may include, for example, friction associated with the bobbins in the tow material feed mechanism, friction associated with any rollers that the tow material passes over, friction associated with any surfaces within the head that the tow material passes over, for example.

[0186] During the laying down of the tow material 22 in a conventional apparatus, the head is moved relative to the mould 3, which provides the driving force P.

[0187] Referring to FIG. 5, the device resistance T l and driving force P are opposed to each other and parallel to each other (i.e., they are aligned). Driving force P also represents the tension in the tow material being laid.

[0188] Device resistance T l If is equal to the driving force P, then a constant laying speed (laying speed of the tow material 22 on the mould 3 ) is achieved, which is also the feed speed of the tow material 22 .

[0189] In other words, a constant laying speed is achieved in linear laying of the tow material 22 if the following formula 1 is satisfied (see also FIG. 5, where the dashed arrow indicates the moving direction of the tow material 22):

[0190]

number

[0191] In a tape laying apparatus in which a shear mechanism (e.g., a shear mechanism similar to shear mechanism 5 described herein) is provided and used, the driving force P is no longer the device resistance force T l In particular, the driving force P is not aligned with the device resistance force T l The driving force P is angled against the device resistance force T l The angle at which the head acts on the mold 3 is determined by the shear angle, which is the angle of the tow material 22 laid down relative to the primary direction of travel (i.e., longitudinal direction) of the head relative to the mold 3. As will be appreciated, the shear mechanism operates by moving the head laterally (perpendicular to the longitudinal direction) relative to the mold 3.

[0192] Therefore, in such a case, the driving force P has a longitudinal component P l and the lateral component P t Typically, regardless of the shear angle, the device resistance T l remains substantially constant.

[0193] As such, at a constant laying speed, Equation 2 holds:

[0194]

number

[0195] Thus, as the shear angle increases, the magnitude of the driving force P increases and therefore the lateral component of this force also increases as shown in Equation 3 below, where θ is the shear angle (see, e.g., FIG. 6, where the dashed arrows indicate the direction of movement of the tow material 22):

[0196]

number

[0197] In a shear mechanism with a gripping shoe and tow guide rollers (such as the shear mechanism 5 described herein with its gripping shoe 53 and tow guide rollers 52), the action of the gripping shoe and tow guide rollers on the tow material 22 serves to resist lateral movement of the tow material across the gripping shoe. In other words, as the shear angle increases, the action serves to inhibit slippage of the tow material 22 across the gripping shoe. Thus, the gripping shoe and tow guide rollers act to provide a lateral friction force T t to provide.

[0198] Lateral component P of driving force P t is the maximum lateral friction force T t,max If it remains less than 0.5 mm, then there is no lateral slippage of the tow material 22 across the gripper shoe.

[0199] Thus, if Equation 4 is as follows, then there is no lateral slippage of the tow material 22 across the gripper shoe.

[0200]

number

[0201] If slippage occurs, then the tow material 22 will not follow the desired tow path as determined by the movement of the head relative to the mold 3, and would take it for granted that slippage would not occur. In fact, the tow material 22 will eventually reach the edges of the gripping shoes 53 and / or tow guide rollers 52, where it will be crushed and / or interfere with the operation of the head.

[0202] Thus, in conventional devices with shear mechanisms, there is a limit to the shear angle that can be achieved, which is the maximum lateral friction force T t,max The maximum lateral friction force can be affected by parameters such as the coefficient of friction of the surface of the tow guide roller 52 and the pressure applied by the gripper shoe 53.

[0203] In many conventional devices, there is a design focus on minimizing the tension in the tow material 22 at the time the tow material 22 is laid down (i.e., at the time of deposition). In conventional devices, this may be sought by actively driving the supply of tow material 22 (e.g., by overfeeding the tow material 22 into the shearing mechanism, if one is included). Additionally or alternatively, in conventional devices, this may be sought by minimizing the total frictional forces on the tow material 22 passing through the device, and in particular the device drag force T l It can be found by minimizing

[0204] In a device having a shear mechanism similar to that described herein (i.e., shear mechanism 5) or that of US Pat. No. 5,999,563, the device resistance force T l is the result of the action of the gripping shoes 53 and the tow guide rollers 52 on the tow material 22. This is due to the lateral friction force T t is required to provide.

[0205] In the device of US Pat. No. 5,999,133, for example, the feed rate of the tow material 22 is synchronized (e.g., mechanically) to the withdrawal rate of the backing material 21. This synchronization tends to minimize tension in the tow material 22. When the bobbin runs out of tow material 22 or accumulates backing material 21, electronic synchronization can be implemented to vary the length of the material 21, the feed and withdrawal of the material 22. However, such electronic synchronization can in some cases prove difficult to implement reliably, which can lead to poor laying, head stoppages, and defects in the laid tow material 22. These problems can be exacerbated, for example, with increased speed of the laying operation and increased frequency of stop-start cycles in the laying operation. Such a system also does not provide any mechanism by which the tension of the tow material 22 can be changed during the laying operation, particularly laying operations that involve shearing of the tow material 22.

[0206] Therefore, the tension control system 7 of some embodiments may include an additional force P m(This additional force can also be called a pulling force or an additional pulling force). This additional force P m may be a force that acts to pull on the tow material 22 and / or the backing material 21 , thus assisting in the feeding of the tow material 22 .

[0207] Thus, during straight laying of tow material, the force responsive to actuation of tension control system 7 can be expressed (for a constant laying speed) as follows:

[0208]

number

[0209] In other words, the device resistance T l Referring to FIG. 7, the driving force P and the combined (i.e., added) additional force P m (In FIG. 7, the dashed arrow indicates the direction of movement of the tow material 22).

[0210] During a shearing operation (ie, steering the tow material 22 by a shearing action using the shearing mechanism 5), the force can be expressed as follows:

[0211]

number

[0212] In other words, the device resistance T l Referring to FIG. 8, the longitudinal component P of the driving force l and the combined (i.e., added) load P m (In FIG. 8, the dashed arrows indicate the direction of movement of the tow material 22).

[0213] The tension control system 7, through active control as described herein, applies an additional force P m Therefore, the tension control system 7 may want to control this additional force P mcan be adjusted to seek to increase the maximum shear angle that can be achieved without substantial lateral slippage of the tow material 22 across the gripper shoe 53.

[0214]

number

[0215] The tension control system 7 also actively controls the device resistance force T as described herein. l (hence, the device resistance T l is the additional force P m , which may be considered to be a tension that can be varied by the controller 73).

[0216] In other words, the lateral component of the driving force P t can be controlled to maintain a no-slip condition defined by the following equation (8):

[0217]

number

[0218] Additional force P m By adjusting the tension control system 7, the tension control system 7 can also adjust the tension of the tow material 22 in the shear mechanism 5 (e.g., the tension between the compression shoe 51 and the gripper shoe 53).

[0219] Therefore, the tension control system 7 determines the lateral component of the driving force P t is the maximum lateral friction force T t,max In order to avoid exceeding the applied force P m may be configured to adjust

[0220] The tension control system 7 additionally controls the applied force P to maintain a predetermined minimum tension in the tow material 22 in the shear mechanism 5 (e.g., the tension between the compression shoe 51 and the gripper shoe 53). mThis predetermined minimum value may be, for example, one of the one or more operating parameters (i.e., the tension set point of the tow material 22).

[0221] A minimum tension of the tow material 22 in the shear mechanism 5 may be required to reduce imperfections in the laid tow material 22. This may include, for example, seeking to ensure that the reinforcing fibers 22a of the tow material 22 slide relative to one another.

[0222] As will be appreciated, the minimum tension of the tow material 22 in the shear mechanism 5 may depend on factors such as the shear stiffness of the tow material 22, the resistance of the reinforcing fibers 22a to slip relative to one another (which may be a property of the fibers 22a and / or the binder material or resin material), the width of the tow material 22 (i.e., the depth across the shear mechanism 5 perpendicular to the longitudinal axis of the tow material 22), the distance between the compression shoe 51 and the gripping shoe 53, and / or similar factors.

[0223] Additional force P m may be adjusted by tension control system 7 in some embodiments to provide a predetermined tension profile in tow material 22. This tension profile may depend on parameters such as the tow material 22, the speed of travel of the head relative to mold 3, the shear angle, or other characteristics of the tow material 22 or the laying process.

[0224] Referring to FIG. 9, the tension control system 7 can be configured to use a predetermined tension (i.e., a desired tension) of the tow material 22 in the shear mechanism 5 and a shear angle, both of which can be examples of operating parameters discussed herein.

[0225] The predetermined tension of the tow material 22 in the shear mechanism 5 may range from a minimum tension discussed herein to a maximum tension, which may be less than or equal to the tension required to maintain a no-slip condition. While no slippage of the tow material 22 across the gripper shoe 53 is ideal, it will be appreciated that in certain applications (e.g., applications where the resulting defects may be acceptable) it may be acceptable to allow some slippage. In some applications, no slippage is important, and as such the maximum tension may be less than the theoretical tension required to maintain a no-slip condition with a safety margin (which may be 1% or more of the theoretical tension, 5% or more of the theoretical tension, 10% or more of the theoretical tension, or 20% or more of the theoretical tension).

[0226] In order to determine the maximum tension (whether the predetermined tension itself or used to set the predetermined tension (which may be a range)), it may be necessary to determine one or more characteristics of the operation of the tow laying head 1 and / or the tow laying system 100.

[0227] For example, the maximum lateral friction force T t,max , and / or the device resistance T l It may be necessary to determine one or more components of.

[0228] For example, the or each characteristic may be determined through experimentation, e.g., by laying down the tow material 22 using the tow laying head 1 and / or system 100 and then inspecting the laid tow material 22 for defects. In some embodiments, the maximum lateral friction force T t,max may be determined through the provision of one or more tape end detectors.

[0229] The or each tape end detector (there may be two tape end detectors) may be positioned relative to the gripping shoe 53 (and / or the compression shoe 51 and / or the tow guide roller 52) to detect, for example, a collision between the detector(s) and the tow material 22 at the point where the tow material 22 enters or exits the gripping area, or alternatively may detect the backing material 21 (e.g. after the backing material 21 has been removed from the tape material 22).

[0230] Thus, the tape end detector is disposed at or toward one end of the gripper shoe 53 (or other component) and configured to detect slippage of the tow material 22 such that the tow material 22 impacts the detector. The tape end detectors arranged in pairs may be disposed, for example, at or toward opposite ends of the gripper shoe 53 (or other component).

[0231] At the or each characteristic (and thus maximum tension) of some embodiments, some embodiments may include a test apparatus including an anchor 501 and a load cell 502 (see FIG. 17). The tow material 22 may be coupled to the anchor 501 and passed through the load cell 502 between the anchor 501 and the compression mechanism 5. This may be used to determine the tape tension (i.e., tension in the tow material 22) for a variety of different operating conditions (e.g., different speeds of movement of the compression mechanism 5 relative to the anchor 501). In other embodiments, the test apparatus may include a motor-driven creel instead of the anchor 501, in which case movement of the compression mechanism 5 relative to the creel is not required as the creel may be rotated to apply tension to the tow material 22.

[0232] Thus, during use of the system 100 and / or the head 1, slippage can be detected, which is determined by the lateral friction force at which slippage occurs, and thus the maximum lateral friction force T t,max This can be used, for example, to ascertain the maximum lateral friction force T t,max may be modeled in terms of operating parameters of the system 100 and / or head 1 (such as the velocity of the head relative to the mold 3).

[0233] These one or more characteristics may be received as input to tension control system 7 (e.g., to controller 73 (e.g., to the processor or processors 73a, which may be via input / output interface 73d)), or may be manually entered from a user interface device 8 (e.g., via a wired or wireless communication link), which may be communicatively connected to tension control system 7.

[0234] The or each characteristic may be stored on computer readable medium 73c, for example, for later retrieval and use by processor(s) 73a.

[0235] Similarly, to determine the predetermined tension (e.g., a range of minimum tensions or the predetermined tension itself), tension control system 7 (e.g., controller 73 (e.g., processor or processors 73a via input / output interface 73d)) may need to receive one or more characteristics of tow material 22-, such as its shear stiffness. These one or more characteristics may enable control system 7 (e.g., controller 73 using processor or processors 73a) to determine the predetermined tension, or may be the predetermined tension itself (which may be, for example, a range of minimum tensions).

[0236] Again, these one or more characteristics may be manually entered via user interface device 8 and may be stored in computer readable medium 73c, for example, for later retrieval and use by processor 73a.

[0237] For example, these properties, or each of these properties, may be determined through experimentation, such as by laying tow material 22 using tow laying head 1 and / or system 100 and then inspecting the laid tow material 22 for defects. Other options include the use of test rigs and / or models generated from experimental results.

[0238] Additionally, some versions of system 100 or tension control system 7 may include a backing material retriever 6 that is driven with a fixed torque, or that is coupled to creel 62 via a clutch mechanism (not shown), which may be a friction clutch. The resistance and drive forces of the backing material retriever 6 in such cases may be measured experimentally to calibrate system 100.

[0239] These and other such systems 100, 7 may include one or more sensors (e.g., ultrasonic and / or contact sensors) that can detect changes in the creel diameter (as material is released or withdrawn) and adjust the operation of the system 100, 7 thus achieving the required tension in the tow material 22.

[0240] The shear angle used as an input to tension control system 7 may be a constant shear angle for a particular operation of tow laying head 1, or may be varied during operation of tow laying head 1. Thus, this shear angle may be the maximum shear angle required for a particular operation of tow laying head 1, or may be varied substantially in real time during operation of tow laying head 1.

[0241] These inputs may be received by controller 73 of tension control system 7 and passed to processor(s) 73a. Accordingly, operation of controller 73 will be understood to result from operation of processor(s) 73a, which may be the result of execution of instructions stored in computer readable medium 73c.

[0242] The controller 73 may also be configured to receive first and second load sensor signals, as will be described, which may be used, for example, as feedback for the controller 73.

[0243] Using one or more of these inputs, the controller 73 can be configured to generate first and second motor control signals and brake signals to control the tension of the tow material 22 in the shear mechanism 5, as described.

[0244] The actual tension in the tow material 22 in the shear mechanism 5 cannot be measured directly because doing so would interfere with the shear operation, but the tension can be estimated or determined using the following equation:

[0245]

number

[0246] In particular, the device resistance T l may be known (e.g., as an experimentally determined characteristic of the tape laying head 1 and as a result of the tension in the tow material 22 upstream of the shear mechanism 5 (e.g., determined using the first load sensor 71). The device resistance force may be stored in a look-up table, and different resistance forces may exist for different respective operating parameters of the system 100 and / or head 1 (e.g., for different speeds of movement of the head relative to the mold). In lieu of a look-up table, the device resistance force may be determined using a model of the resistance forces under different operating parameters. Similarly, the shear angle (θ) may be a parameter provided to the controller 73, as described. The applied force P m is the force provided by operation of the tension control system 7 and may be represented by the tension in the backing material downstream of the shear mechanism 5.

[0247] The tension in the tow material 22 between the shear boundaries can be represented by the driving force P Thus, the controller 73 may be configured to control the first and / or second motor control signals and / or the brake signal to adjust (i.e., vary) the tension in the tow material 22 between the shear boundaries. The controller 73 may monitor this tension in the tow material 22 (i.e., by monitoring the drive force P). Control of the first and / or second motor control signals and / or the brake signal may be configured to adjust (i.e., vary) the tension in the tow material 22 between the shear boundaries. l , and / or additional force P mcan be adjusted (i.e., varied) to adjust the tension of the tow material 22 between the shear boundaries. This adjustment can be an active adjustment during operation of the tape laying head 1.

[0248] The effect of the adjustment can be determined by use of the first and second load sensor signals, which are related to the device resistance force T l , and / or additional force P m , provides feedback that can be used as an indirect measure of the tension in the tow material 22 between the shear boundaries (represented by the driving force P), so that it can be monitored.

[0249] This feedback may result in further variations in the first and / or second motor control signals and / or the brake signal by the controller 73. In some embodiments, the controller 73 may be configured to make such variations in the first and / or second motor control signals based on the second load sensor signal.

[0250] In some embodiments, the controller 73 may be configured to make such variations on the brake signal based on the first load sensor signal, hi some embodiments, the controller 73 is configured to make such variations based, at least in part, on the diameter of the backing material collector 6 and / or tape supply 4 (and / or associated creel 42 / 62).

[0251] As previously discussed, the tension control system 7 may, in some embodiments, be used with a tape 2 that does not include a backing material 21 (in other words, the tape laying system 100 may not include a backing material recovery portion 6). In such embodiments, the tow material 22 may be attached to a surface of the mold, for example, by using a binder material.

[0252] Isolation of areas of tension According to some embodiments, the tension in the tow material 22 and the backing material 21 can be isolated and substantially independently controlled in different regions within the tow laying head 1 .

[0253] In particular, these regions may include a first region from the tape supply 4 to the shear mechanism 5 (particularly to the gripping region), a second region within the shear mechanism 5 (particularly between the shear boundaries), and a third region between the shear mechanism 5 and the backing material recovery 6 (particularly from the compression shoe 51). This may be achieved, for example, by applying a suitable force to the tow material 22 by the tow guide rollers 52 and the gripping shoe 53 in relation to the first region to effect separation.

[0254] Thus, in some embodiments, the tension in the tow material 22 and the tension in the backing material 21 may be controlled substantially independently of the tension in the tow material 22 between the shear boundaries. In other words, the tension in the tow material 22 in the second region may be controlled substantially independently of the tension in the tow material 22 or the backing material 21 in the first and third regions.

[0255] This may allow, for example, higher acceleration and deceleration of the movement of the compression shoe 51 relative to the mould 3 without substantially affecting the laying operation (ie no undue tension in the second region).

[0256] Thus, some embodiments may include forcing the gripper shoe 53 against the tow guide roller 52 with sufficient force to separate the tension in the second region from the tension in the first region and / or third region. Thus, the tension in the first and / or third region may be increased and higher accelerations and / or decelerations may be achieved without substantially affecting the shear actuation.

[0257] Web Mechanism As described herein, the tow material 22 may include a binder or resin material that makes the tow material sticky and therefore prone to sticking to the compression shoe 51. This in turn may mean that the material of the compression shoe 51 construction needs to be such that the risk of this unintended sticking is reduced. Furthermore, during the laying down of the tow material 22 and shearing of the tow material 22, the thickness of the material 22 increases and its width decreases, which imposes a lateral compressive stress on the tow material 22 (due to the shear deformation of the tow material 22). This may cause buckling and other such defects (e.g., wrinkles).

[0258] Accordingly, some embodiments may include a web mechanism 200 configured to apply a web of material 201 to one side of the tow material 22 that contacts the compression shoe 51. This application may be performed by the web mechanism 200 before the tow material reaches the compression shoe 51 and / or the tow guide rollers 52 and / or the gripper shoe 53.

[0259] The web 201 may increase the lateral buckling resistance of the tow material 22 and / or may provide a surface in contact with the compression shoe 51 that is less likely to adhere to the compression shoe 51 (the web 201 may not include an adhesive material).

[0260] A web mechanism 200 is shown, for example, in Figure 12. As can be appreciated, Figure 12 is a variation of the embodiment described with reference to Figure 3 and, for the sake of brevity, will not be described again (and, for the sake of brevity, many of the reference numbers have been omitted from Figure 12). Accordingly, reference should be made to Figure 3 and the relevant parts of the description.

[0261] The web mechanism 200 may include a web material supply 202 and a web material return 203. The web material supply 202 may be associated with a brake 202a configured to brake the release of the web 201 from the supply 202. The web material supply 202 may be in the form of a creel, for example, around which a supply of the web 201 is wound. The web material supply 202 may be generally located upstream (with respect to the movement of the tow material 22) of the shear mechanism 5. The web material supply 202 may be generally located aft of the shear mechanism 5 with respect to the direction of travel of the web material relative to the mold 3.

[0262] The web material recovery portion 203 may be associated with a motor 203a configured to pull the web 201 from the supply portion 202. The web material recovery portion 203 may be in the form of a creel, for example, around which the used web 201 is wound. The web material recovery portion 203 may be generally positioned forward of the shear mechanism 5 with respect to the direction of advancement of the web material relative to the mold 3.

[0263] The web 201 may travel (along an associated path) from the web material supply 202 and contact the tow material 22 prior to the tow material 22 entering the gripping area (e.g., the path between the tow guide rollers 52 and the gripping shoe 53). The web 201 may be pressed against the tow material 22 by the action of the tow guide rollers 52 and the gripping shoe 53. The web 201 may be positioned such that it is between the tow material 22 and the tow guide rollers 52.

[0264] The path of the web 201 may follow the path of the tow material 22 through the compression shoe 51. After the tow material 22 has been laid down into the mold 3 by the compression shoe 51, the web 201 may be removed from the tow material 22 and advanced to a web material recovery section 203. This may be accomplished by positioning the web material recovery section 203 relative to the compression shoe 51 such that the web 201 is lifted from the tow material 22 as the tow material 22 (and web 201) leaves the compression shoe 51. As such, the web material recovery section 203 may be positioned further away from the mold 3 than the compression shoe 51 leaves the mold 3.

[0265] Operation of the brake 202a and motor 203a of the web mechanism 200 may be controlled by the controller 73 (or a separate controller may be provided).

[0266] As will be appreciated, the web 201 is positioned between the tow material 22 and the compression shoe 51. As such, there is a reduced risk of unintended adhesion of the tow material 22 to the compression shoe 51. Additionally, the web 201 provides structural support to the tow material 22. This can be particularly useful in connection with delicate (e.g., thin) tow materials 22.

[0267] The ideal characteristics of Web 201 are: exhibiting low shear stiffness and good shear quality (i.e., little or no wrinkles or other defects during shearing); - exhibiting high lateral compressive buckling resistance (e.g., by having fibers or reinforcing members perpendicular to the path of the tow material 22) (e.g., the lateral compressive buckling resistance can be the same or higher than that of the tow material 22); - adheres to the tow material 22 and can be debonded as required; - having an upper surface with a low coefficient of friction; and exhibiting a higher shear locking limit or maximum shear angle of the path (whichever is highest) than the tow material 22.

[0268] The shear locking limit can be defined as the shear angle at which the fibers can no longer rearrange during deformation (i.e., the fibers are locked). Thus, further shear deformation (further increasing the shear angle) would lead to the formation of defects such as wrinkles. Intra-tow shear is not possible beyond the locking limit (i.e., the fibers cannot slide / rearrange).

[0269] The web 201 may be a peel ply tape. The web 201 may be a woven material and may be formed from low friction fibers. The web 201 may be formed from, for example, polytetrafluoroethylene (PTFE) (such as Teflon). The web 201 may have longitudinal and transverse fibers that may be substantially perpendicular to one another.

[0270] The web 201 may include an adhesive on one side thereof, which may be the side that contacts the tow material 22 in use.

[0271] Compression Roller The embodiments herein are generally described with reference to the compression shoe 51. However, in some embodiments, reference is made to the compression roller 300. In this regard, see FIGS. 13-15. In some embodiments, the compression roller 300 replaces the compression shoe 51 and the tow guide roller 52 may not be present. Instead, the gripper shoe 53 may engage the compression roller 300, in other words the compression roller 300 may perform the role of both the compression shoe 51 and the tow guide roller 52. Such an embodiment may be implemented with other embodiments described herein, for example to control tension in the tow material 22 and / or to isolate tension zones as described.

[0272] 13 and 14, in particular, the radius of a cross section through the compression roller 300 can be greater than the distance between the contact point of the gripper shoe 53 (e.g., at its distal most end) and the compression roller 300. This contact point can be below the midpoint of the compression roller 300 (the midpoint can be a central axis therethrough, which can be the axis of rotation of the compression roller 300). The compression roller 300 is configured to rotate about an axis generally perpendicular to the path of the tow material 22. The compression roller 300 can be configured to contact the mold 3 and press the tow material 22 against the mold 3.

[0273] As will be appreciated, in such embodiments, shearing of the tow material 22 may occur between the contact point between the gripper shoe 53 and the compression roller 300 and the contact point between the compression roller 300 and the mold 3 (which, of course, is a line in some embodiments).

[0274] According to some embodiments, the radius of the cross section through the compression roller 300 may be reduced to provide a minimum shear gap (i.e., the distance between two shear boundaries), which in turn promotes intra-tow shear since the effective length of contact between adjacent fibers (referring to the portion of the tow material 22 that is sheared) is minimized, thus reducing the associated friction and allowing fiber slippage or rearrangement.

[0275] As described herein, the compression roller 300 may be configured to rotate relative to the gripper shoe 53 and mold 3. This rotation may be driven by movement of the compression roller 300 over the mold 3 and / or may be driven directly by a motor. However, in some embodiments, the compression roller 300 is fixed from rotation with respect to the gripper shoe 53 and mold 3, in which case the compression roller 300 may slide over the mold 3.

[0276] The compression roller 300 may be formed (or coated) with, for example, PTFE. The compression roller 300 may be formed from a relatively low friction material. The compression roller 300 may have a substantially rigid outer surface or may have a relatively soft outer surface. In some embodiments, the compression roller 300 may be formed from a silicone roller with a PTFE sleeve. In some embodiments, the compression roller 300 is sufficiently soft to allow the compression roller 300 to conform to non-flat and uneven surfaces by deforming to match surface variations of the mold 3.

[0277] Advantages of such an embodiment may include applying a membrane stress to the portion of the tow material 22 being sheared, which balances the lateral compressive stress that the tow material may experience due to shearing of the tow material (as the tow material is pulled around the surface of the compression roller 300 during shearing). The stress depends on the radius of the compression roller 300 (smaller radii lead to higher stresses), the shear gap (i.e., the distance between the shear boundaries), and the tow material tension.

[0278] The absence or reduction of out-of-plane shear stresses (e.g., stresses imposed on the tow material 22 due to the minimization of the sliding motion of the compression roller 300 compared to the compression shoe 51 embodiment) may reduce the risk of defects due to fiber separation (especially in sticky tow materials). The compression roller 300 may only be required to slide (i.e., motion parallel to the axis of rotation of the compression roller 300) to generate the lateral movement required to enable shearing. The compression roller 300 may rotate about its axis of rotation in some embodiments (i.e., unlike the compression shoe 51 embodiment).

[0279] In some embodiments (see FIG. 15), the compression roller 300 may be flexible along its length such that the compression roller 300 may form a curve. The gripping shoe 53 may be correspondingly flexible such that the gripping shoe 53 may likewise form a curve along its length (in which case resilient biasing members may be provided along the length of the flexible gripping shoe 53 to maintain contact with the compression roller 300, each resilient biasing member may include a spring-loaded piston). This may allow, for example, to lay down tow material in a single or double curved mold 3. In other words, such an embodiment may allow use in connection with more complex molds 3.

[0280] These embodiments may be used with or without the web mechanism 200.

[0281] Additionally, although a gripping shoe 53 is described, these embodiments may use gripping rollers.

[0282] Slip compensation mechanism Some embodiments may include a slip compensation mechanism 400 (see FIG. 16). The slip compensation mechanism 400 may be configured to provide some compensation for lateral slippage of the tow material 22 relative to the gripper shoe 53, and may be used in embodiments having either the compression shoe 51 or the compression roller 300 (with or without the web mechanism 200), and may be implemented in combination with other described embodiments, such as tension control and / or tension zone isolation techniques. Indeed, in some embodiments, the slip compensation mechanism 400 may be applied to other tow material laying apparatus, including those taught in U.S. Pat. No. 6,399,323.

[0283] The slippage compensation mechanism 400 may be configured to receive a signal indicative of slippage of the tow material 22 relative to the gripping shoe 53, and in particular, may receive a signal indicative of slippage greater than a threshold distance, which, as will be appreciated, may be lateral slippage along the gripping shoe 53.

[0284] In some embodiments, the slippage compensation mechanism 400 includes a sensor 401 that senses slippage of the tow material 22 and generates a signal. However, in some embodiments, the sensor 401 is provided remotely. Two possible sensor locations are shown diagrammatically in FIG.

[0285] The sensor 401 may be a tape or web edge sensor.

[0286] The sensor 401 may include an optical sensor. The optical sensor may be configured, for example, to sense the blocking of light (e.g., infrared light) from a light source (which may be part of the sensor) by the tow material 22. Thus, the sensor 401 may be located upstream of the gripper shoe 53 with respect to the direction of travel of the tow material 22 and offset to one side of the normal path of the tow material 22. If the tow material 22 triggers the sensor 401, this may indicate slippage of the tow material 22, depending on the location of the sensor 401. Similarly, the sensor 401 may be configured to sense lateral movement of the backing material 21 instead of the tow material 22, but in a similar manner, downstream of the gripper shoe 53. Of course, when sensing lateral movement of the tow material 22, this may be the tow material 22 and backing material 21 combined in some embodiments.

[0287] The sensor 401 may include sub-sensors for detecting lateral slippage in a first and second direction (each sub-sensor configured to detect slippage in one of two directions).

[0288] The sensor 401 could take a number of different forms, and another type of possible optical sensor is a camera that can capture and analyze images of the tow material 22. Non-optical sensors can be used, and these can include, for example, ultrasonic sensors.

[0289] The slip compensation mechanism 400 may be configured to move the shear mechanism 5 (and in particular the shear boundary) laterally relative to the tape supply 4 and / or the backing material collector 6 to compensate for the detected slippage (detected using the signal from the sensor 401). The slip compensation mechanism 400 may thus be configured to move the shear mechanism 5 (and in particular the shear boundary) relative to the mould 3 in a direction that is perpendicular to the direction of travel of the compression shoe 51 (or the compression roller 300). The tape supply 4 and / or the backing material collector 6 may, for example, be referred to as a creel unit 600 (see FIG. 18). The creel unit 600 may include first and second load sensors 71, 72. The slip compensation mechanism 400 may thus be configured to move the shear mechanism 5 relative to the creel unit 600.

[0290] The shear boundary created by the pressing of the compression shoe 51 or the compression roller 300 (as the case may be) may be referred to as the first shear boundary. The first shear boundary may slide laterally on the surface of the laid tow material 22. The tow material 22 may be considered to be fixed (relative to the mold) at this position once the tow material 22 is attached to the surface of the mold 3. Thus, by displacing the shear mechanism 51, the tow material 22 may be moved at the second shear boundary (i.e., the boundary created by the pressing of the gripper shoe 53 and the tow guide roller 52 or the pressing of the gripper shoe 53 against the compression roller 300 (as the case may be)). However, in some embodiments, only the second shear boundary is moved.

[0291] The shear boundary generated by the compression shoe or compression roller (depending on which shear mechanism is used) (first shear boundary) can slide laterally on the surface of the tape material, which is also considered to be fixed in this position when the tape is applied to the surface of the mold. Thus, by displacing the shear mechanism, in effect, the tape is displaced at the shear boundary (second shear boundary) generated by the gripper shoe pressing against the tow guide roller or the gripper shoe pressing against the compression roller (depending on which shear mechanism is used) and which is the origin of the misalignment.

[0292] In another example of the mechanism, only the second shear boundary may be actuated, however this creates some complications in terms of packaging all of the necessary components within the tape laying system.

[0293] The slip compensation mechanism 400 may include one or more rails 402, to which the shear mechanism 5 is mounted for movement thereon. The or each rail 402 may be carried by a mounting arrangement (e.g., one or more members, not shown, that receive the or each rail 402) on another part of the head 1 or system 100, and the or each rail 402 may be movable relative to the mounting arrangement during its lateral movement, as described above. Thus, the shear mechanism 5 may be movable relative to the mounting arrangement (i.e., relative to the head 1 or other part of the system 100). The movement of the shear mechanism 5 relative to the mounting arrangement may be driven in a number of different ways. For example, the slip compensation mechanism 400 may include a belt or chain drive, a pneumatic or hydraulic ram, or a rack and pinion drive to drive the lateral movement of the shear mechanism 5. In some embodiments, the or each rail 402 is part of the head 1 or system 100, and the mounting arrangement is attached to the shear mechanism 5.

[0294] In some embodiments, slippage occurs in the gripping area, and thus movement of the shear mechanism 5 relative to the tape supply 4 and / or backing material return 6 can be used to correct this slippage. In some embodiments, the tow material does not contact any other portion of the shear mechanism 5 before reaching the gripping area.

[0295] This is shown, for example, in Figures 19-21. In Figure 19, the shear mechanism 5 is in a home position (e.g., the tow material 22 is substantially centered along the compression shoe 51; Figure 20 shows the same apparatus, but with slippage occurring and the original tow material shown in dashed lines for reference). Figure 21 shows the shear mechanism 5 at one extreme of its position relative to, for example, the creel unit 600.

[0296] The lateral movement thus possible may be limited (e.g. by the length of the or each rail 402 or drive). Thus, during operation, the position of the shearing mechanism 5 relative to the tape supply 4 and / or backing material recovery 6 needs to be reset (or "homed") (in a reset operation). This can be achieved, for example, by releasing the gripping areas (i.e. by releasing the tow guide rollers 52 and / or the gripping shoes 53 from each other) while the compression shoe 51 (or compression roller 300) is not in contact with the mold 3. The shearing mechanism 5 can then be moved before the gripping areas are reengaged. The tension in the backing 21 can be increased again after this is completed, but before the laying of the tow material 22 is started (or resumed).

[0297] In some embodiments, the slip compensation mechanism 400 includes one or more boundary members (not shown). The or each boundary member is configured to inhibit or substantially prevent lateral movement of the tow material during a reset operation. The or each boundary member may be positioned such that the tow material 22 will abut against the boundary member and prevent lateral (or further) movement of the tow material 22. The or each boundary member may be part of a guide member through or over which the tow material 22 passes (e.g., before reaching the gripping area). The guide member may include a pair of upstanding boundary members arranged such that one of the pair is on either side of the tow material 22. The guide member may include a plate over which the tow material 22 may pass and from which the boundary member extends.

[0298] In some embodiments, the slip compensation mechanism 400 may be configured to identify the operations that caused the slip. These may be, for example, parameters of the operation of the system 100 and / or head 1 (such as the speed of movement of the compression shoe 51 or compression roller 300 relative to the mold 3). The slip compensation mechanism 400 may be configured to feed these back to the controller 73, which may adjust the operation of the system 100 and / or head 1 to reduce the risk of slippage, for example, by avoiding one or more of those operations or compensating for them. This may include slowing down the movement of the release of the tow material 22 from the tape supply 4 or adjusting the tension of the tow material 22.

[0299] Although the embodiments have been described with reference to the shear mechanism 5 as being generally mounted to the rail or rails 402 and moved by the slippage compensation mechanism 400, in some embodiments, only the gripper shoe 53 and the tow guide roller 54 are mounted to the rail or rails 402 and moved by the slippage compensation mechanism 400 (such movement being relative to the compression shoe 51, for example). In some embodiments, the gripper shoe 53 and the two guide rollers 54 in combination (without the compression shoe 51) may be referred to as a pinch assembly.

[0300] Installation work As will be appreciated, embodiments include a method of laying down tow material 22 in a mold 3 in which the shear of the tow material 22 is used to steer the laid down tow material 22. During the laying down operation, a tension control system 7 acts to adjust the tension of the tow material 22 in the shear mechanism 5 as will be described.

[0301] others Operation of tension control system 7 and / or web mechanism 200 and / or slippage compensation mechanism 400 may be controlled by controller 73, which may execute instructions using processor or processors 73a, instructions stored on computer readable medium 73c. ​​Thus, embodiments may include instructions that may form a computer program. Embodiments also include computer readable media having these instructions stored thereon.

[0302] References to tension in the tow material 22 in the shear mechanism 5 are references to tension in the tow material 22 between the shear boundaries. In the illustrated embodiment, these are defined by a compression shoe 51 (e.g., at its leading edge) and a gripping shoe 53 (e.g., at its distal most end), however, other forms of shear mechanism 5 are possible which may result in shear boundaries being defined by different physical characteristics of the tow laying head 1. It should be understood that the same control techniques described herein may be applied to a wide variety of tow laying heads 1 having different forms of steering mechanisms (of which the shear mechanism 5 is just one example).

[0303] As used in this specification and claims, the terms "comprise" and "comprising" and variations thereof mean that the specified features, steps or whole entities are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0304] The features disclosed in the above description, or in the following claims, or the accompanying drawings, expressed in specific forms thereof, or in terms of means for performing the disclosed functions, or methods or steps for suitably achieving the disclosed effects, may be utilized to realise the invention in its diverse forms, either individually or in any combination of such features.

[0305] Although several exemplary embodiments of the present invention have been described, the scope of the appended claims is not intended to be limited to only these embodiments. The claims should be construed literally, intentionally, and / or to encompass equivalents.

Claims

1. 1. A tape laying head configured to lay a tow material into a mold in building a composite structure, the tape laying head comprising: a shear mechanism configured to receive the tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material during steering of the tow material; a tension control system configured to control the lateral component of the driving force acting on the tow material to be equal to or less than a maximum lateral friction force associated with the shear mechanism by varying the tension applied to the tow material by the tension control system and monitoring the driving force.

2. 2. The tape laying head of claim 1, wherein the tension control system further includes a first load sensor configured to generate a first load sensor signal representative of a tension in the tow material between the tow supply and the shear mechanism, the first load sensor signal being used to monitor the drive force.

3. 3. The tape laying head of claim 1, wherein the tow material comprises a backing material, the shear mechanism is configured to separate the tow material from the backing material, and the tension control system further includes a second load sensor configured to generate a second load sensor signal representative of the tension in the backing material between the shear mechanism and a backing material recovery section, the second load sensor signal being used to monitor the drive force.

4. 4. The tape laying head of claim 3, wherein the shear mechanism further comprises a tow guide roller and a gripper shoe or roller, and the tension control system further comprises a first motor configured to drive rotation of the tow guide roller, and tension is applied at least in part by the first motor.

5. 5. The tape laying head of claim 4, wherein the tension control system further includes a second motor configured to drive operation of the backing material recovery section, and wherein the tension is applied at least in part by the second motor.

6. 6. The tape laying head of claim 3, wherein the tension control system further comprises a brake associated with the tape supply and configured to brake the feeding of the tow material from the tape supply to the shear mechanism, and wherein the tension is applied at least in part by the brake.

7. 4. A tape laying head as claimed in any one of claims 1 to 3, wherein the shear mechanism includes a compression roller and a gripper shoe or roller, a first shear boundary of the pair of shear boundaries being defined by a contact point between the compression roller and the mould in normal operation, and a second shear boundary of the pair of shear boundaries being defined by a contact point between the compression roller and the gripper shoe or roller.

8. 8. A tape laying head as claimed in any one of claims 1 to 7, further comprising a web mechanism, the tow material comprising a web prior to shear deformation of the tow material, the web mechanism configured to remove the web from the tow material after the tow material has been laid into the mould.

9. 9. The tape laying head of claim 8, wherein the web mechanism is further configured to apply the web to the tow material prior to shearing the tow material.

10. 10. The tape laying head of claim 9, wherein the web mechanism includes a supply of web material and a web material return associated with a motor, the motor configured to actuate the web material return to pull the web from the supply of web material.

11. 11. A tape laying head as claimed in any one of claims 1 to 10, further comprising a tow material supply section and / or a backing material recovery section, and a slippage compensation mechanism configured to move the shear mechanism laterally relative to the tow material supply section and / or the backing material recovery section such that lateral slippage of the tow material is compensated, thereby compensating for lateral slippage of the tow material.

12. 12. The tape laying head of claim 11, wherein the slip compensation mechanism includes one or more rails configured to allow movement of the shear mechanism or one or more of the tow guide roller and gripper shoe relative to a portion of the head, and a drive for driving movement of the shear mechanism or the tow guide roller and gripper shoe.

13. 13. The tape laying head of claim 11 or 12, wherein the slip compensation mechanism further comprises a sensor configured to sense lateral slippage of the tow material.

14. 14. A tape laying head as claimed in any one of claims 1 to 13, wherein the tension control system is further configured to maintain the drive force above a minimum threshold by varying the tension.

15. A tape laying head as claimed in any one of claims 1 to 14, wherein the tow material is a pre-impregnated tow material.

16. A tape laying system comprising a tape laying head according to any one of claims 1 to 15.

17. 1. A controller for use in a tension control system of a tape laying system, comprising: The tape laying system includes a shear mechanism configured to receive a tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by the shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a lateral component relative to the tow material while steering the tow material; the controller is configured to control the lateral component of the driving force acting on the tow material to be equal to or less than a maximum lateral friction force associated with the shear mechanism by varying a tension applied to the tow material and by monitoring the driving force.

18. 18. The controller of claim 17, further configured to receive a first load sensor signal representative of a tension in the tow material between the tow supply and the shear mechanism, the first load sensor signal being used by the controller to monitor the drive force.

19. 19. A controller as described in claim 17 or 18, wherein the tow material comprises a backing material, the shear mechanism is configured to separate the tow material from the backing material, and the controller is further configured to receive a second load sensor signal representative of a tension in the backing material between the shear mechanism and a backing material recovery section, the second load sensor signal being used by the controller to monitor the drive force.

20. 20. The controller of claim 19, further configured to output a first motor signal, the shear mechanism further including a tow guide roller and a gripping shoe or roller, a first motor driving rotation of the tow guide roller, the first motor signal controlling operation of the first motor, and the tension being applied at least in part by the first motor.

21. 21. The controller of claim 20, further configured to output a second motor signal, a second motor driving operation of the backing material recovery portion, the second motor signal controlling operation of the second motor, and the tension being applied, at least in part, by the second motor.

22. 22. The controller of claim 19, wherein a brake is associated with a tape supply and configured to brake the feeding of the tow material from the tape supply to the shear mechanism, the controller configured to generate a brake signal to control the brake, and the tension is applied at least in part by the brake.

23. A controller according to any one of claims 17 to 22, further configured to maintain the drive force above a minimum threshold by varying the tension.

24. 24. The controller of any one of claims 17-23, wherein the tape laying system may further include a web mechanism, the tow material comprising a web prior to shear deformation of the tow material, and the controller is further configured to actuate the web mechanism to remove the web from the tow material after the tow material is laid into a mold.

25. 25. The controller of claim 24, further configured to actuate the web mechanism to apply the web to the tow material prior to shearing the tow material.

26. 26. The controller of claim 25, wherein the web mechanism may include a supply of web material and a web material return associated with a motor, the controller further configured to operate the motor to pull the web from the supply of web material.

27. 27. A controller according to any one of claims 17 to 26, wherein the tape laying system further comprises: a tow material supply and / or backing material recovery section; a slip compensation mechanism, The controller is further configured to actuate the slip compensation mechanism to move the shear mechanism laterally relative to the tow material supply section and / or the backing material recovery section, thereby compensating for lateral slippage of the tow material.

28. 28. The controller of claim 27, wherein the slip compensation mechanism comprises: one or more rails configured to permit movement of one or more of the shear mechanism, or the tow guide rollers and gripper shoes, relative to a portion of the system; a drive unit; The controller is configured to operate the drive to drive movement of the shear mechanism or the tow guide roller and the gripper shoe.

29. 29. The controller of claim 27 or 28, further configured to receive a signal from a sensor indicative of lateral slippage of the tow material.

30. 1. A control method for use in a tension control system of a tape laying system, comprising: The tape laying system includes a shear mechanism configured to receive a tow material from a tow supply and steer the tow material by applying a shear deformation to the tow material between a pair of shear boundaries defined by a shear mechanism, the shear mechanism further configured to apply a driving force to the tow material, the driving force having a longitudinal component and a transverse component relative to the tow material during steering of the tow material; The method includes controlling a lateral component of the driving force acting on the tow material to be equal to or less than a maximum lateral friction force associated with the shear mechanism by varying a tension applied to the tow material and monitoring the driving force.

31. 31. The control method of claim 30, further comprising: receiving a first load sensor signal representative of a tension in the tow material between the tow supply and the shear mechanism; using the first load sensor signal to monitor the driving force; A control method comprising:

32. 32. The method of claim 30 or 31, wherein the tow material comprises a backing material, and the shear mechanism is configured to separate the tow material from the backing material, the method further comprising: receiving a second load sensor signal representative of tension in the backing material between the shear mechanism and the backing material recovery portion; using the second load sensor signal to monitor the driving force; A control method comprising:

33. 33. The method of claim 32, further comprising outputting a first motor signal, wherein the shear mechanism may further comprise a tow guide roller and a gripping shoe or roller, a first motor may drive rotation of the tow guide roller, and the first motor signal may control operation of the first motor, and the tension is applied at least in part by the first motor.

34. 34. The control method of claim 33, further comprising outputting a second motor signal, the second motor driving operation of the backing material recovery portion, the second motor signal controlling operation of the second motor, and the tension being applied at least in part by the second motor.

35. 35. The method of claim 32, wherein a brake is associated with a tape supply and configured to brake feeding of the tow material from the tape supply to the shear mechanism, the method further comprising: generating a brake signal to control the brake, wherein the tension is applied at least in part by the brake.

36. 36. A method according to any one of claims 30 to 35, further comprising maintaining the drive force above a minimum threshold by varying the tension.

37. 37. The method of claim 30, wherein the tape laying system further comprises a web mechanism, the tow material comprising a web prior to shear deformation of the tow material, the method further comprising: and actuating the web mechanism to remove the web from the tow material after the tow material has been laid down in a mold.

38. 38. The method of claim 37, further comprising actuating the web mechanism to apply the web to the tow material prior to shearing the tow material.

39. 40. The method of claim 38, wherein the web mechanism includes a supply of web material and a web material return associated with a motor, the method further including operating the motor to pull the web from the supply of web material.

40. 40. A method of control according to any one of claims 30-39, wherein the tape laying system further comprises a tow material supply section and / or a backing material recovery section and a slippage compensation mechanism, the method further comprising activating the slippage compensation mechanism to move the shear mechanism laterally relative to the tow material supply section and / or the backing material recovery section, thereby compensating for lateral slippage of the tow material.

41. 41. The method of claim 40, wherein the slip compensation mechanism may include one or more rails and a drive configured to enable movement of one or more of the shear mechanism or the tow guide roller and the gripper shoe relative to the portion of the system, the method further comprising actuating the drive to drive movement of the shear mechanism or the tow guide roller and the gripper shoe.

42. 42. A method as recited in claim 40 or 41, further comprising receiving a signal from a sensor indicative of lateral slippage of the tow material.

43. A computer readable medium having instructions stored thereon which, when executed, cause operation of a control method according to any one of claims 30-42.

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