NASA CASE NO.

PRINT FIG. 1

NOTICE

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LAR 14047-1

The invention disclosed in this document resulted from research in aeronautical and

space activities performed under programs of the National Aeronautics and Space

Administration. The invention is owned by NASA and is, therefore, available for

licensing in accordance with the NASA Patent Licensing Regulation (14 Code of

Federal Regulations 1245.2).

To encourage commercial utilization of NASA-owned inventions, it is NASA policy to

grant licenses to commercial concerns. Although NASA encourages nonexclusive

licensing to promote competition and achieve the widest possible utilization, NASA

will provide the necessary incentive to the licensee to achieve early practical

application of the invention.

Address inquiries and all applications for license for this invention to NASA Patent

Counsel, Langley Research Center, Code 143, Hampton, Virginia 23681-0001.

Serial No.: 07/953,562

09-29/92 LaRC /

(NASA-Case-LAR-14047-I) METHOD ANO N93-19038

APPARATUS FOR THREE DIMENSIONAL

ERAIO[NG Patent Application (NASA)

18 p Uncles

G3/31 0149921
METHOD AND APPARATUS FOR THREE DIMENSIONAL BRAIDER 

NASA Case No. LAR 14047-1 

Braiding apparatus generally consist of a braiding surface 

upon which travel a number of yarn carrier members which dispense 

the braiding fibers. Use of a curved braiding surface rather than 

a flat surface reduces the surface area needed to accomodate a 

moderate range of braiding angles. Various braiding patterns are 

possible by manipulation of the carrier member positions on the 

braiding surface. Many devices use a push/pull mechanism to change 

the positions or entire rows and columns of carrier members. Other 

devices use self-propelled carriers traveling in a fixed pattern 

determined by a preset track arrangement. The designs of these 

braiding apparatus do not permit fabrication of complex, threedimensional braided articles because the apparatus provide only a 

limited range of braid angles the motions of the yarn carriers is 

generally restricted. 

The present invention consists of yarn carrier members which 

are individually self-propelled in four directions between pivot 

discs which are located on a curved, segmented and movable braiding 

surface. The curved, segmented surface effectively allows a much 

wider range of braiding angles than could be achieved with prior 

flat or curved braiding surfaces. In addition, the independent 

motion of the carrier members permits complex motion that is 

monitored and controlled by computer. The novelty of the present 

invention encompasses its ability to produce complex threedimensional braided articles that require a wide range of braid 

angles and independent yarn carrier movement. 

Inventor : 

Addrress : 

Gary L. Farley 

705 Dandv Loop Rd. 

Employer: 

initial Evaluator: Bland Stein 

Serial No.: 071953,562 

Filed: 09-29-92 
s_

LAR 14047-1 -1- PATENT APPLICATION

METHOD AND APPARATUS FOR THREE DIMENSIONAL BRAIDING

Ori.qin of the Invention

5 The invention described herein was made by an employee of the United

States Government and may be used by or for the Government for

governmental purposes without the payment of any royalties thereon or

therefor.

10 Back.qround of the Invention

1. Field of the Invention

15

This invention relates generally to methods and apparatuses for braiding

articles and more specifically to three-dimensional braiding of fibers useful inter

alia as fiber reinforced structural preforms.

2. Description of the Related Art

20 Braiding apparatuses generally consist of a braiding surface upon which

travel a plurality of yarn carrier members which dispense the braiding fibers.

The braiding fibers generally intersect in an area near the article being braided,

hereafter referred to as the braiding zone.

Various braiding surfaces have been developed, with the majority being

25 a simple flat plane, as disclosed in U.S. Pat. No. 4,881,444. Flat surfaces have

the disadvantage that extremely large surface areas may be needed to

accommodate a moderate range of braiding angles. In addition, flat braiding

surfaces cause difficulties in maintaining yarn tension, since carrier members

at different braid angles require different length yarns. To address this difficulty,

30 some braiding machines have curved braiding surfaces that attempt to maintain
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LAR 14047-1 -2-

constant yarn tension by maintaining the

distance from the braiding zone.

Various braiding patterns are possible by manipulation of carrier member

positions on the braiding surface. Many devices use a push/pull mechanism

to change the carrier positions of entire rows or columns of carrier members,

as disclosed in U.S. Pat. No. 4,885,973. Other devices use self-propelled

carriers traveling in a fixed pattern determined by a preset track arrangement,

as disclosed in U.S.Pat. No. 4,972,756.

Most braiding machines incorporate some features to maintain yarn

tension and to rewind yarn. A common means to accomplish these goals is a

coil spring or an electric motor with a friction coupling.

PATENT APPLICATION

carrier members at a constant

Summary of the Invention

15 It is accordingly an object of this invention to provide a braiding machine

capable of achieving a wide range of arbitrary weave angles in order to

fabricate three-dimensional braided articles.

More specifically, this invention is directed to a braiding machine

comprising a curved, segmented and movable braiding surface whereby the

20 curved surface effectively allows a wider range of braiding angles than can be

obtained with a flat braiding surface of comparable area. A plurality of

individually self-propelled carrier members move across the braiding surface by

movement from pivot disc to pivot disc. The motion of the carrier members is

electronically monitored and controlled by computer. The yarn carriers have

25 dedicated motors which control yarn tension and allow unlimited yarn rewind.

Brief Description of the Drawin,qs

FIG. 1 is a front view of a curved, multi-segmented braiding surface;
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LAR 14047-1 -3- PATENT APPLICATION

FIG. 2 is an end view of the curved braiding surface demonstrating

movement of several braiding segments;

FIG. 3 is a perspective of several pivot discs which lie on the braiding

surface;

FIG. 4 is a detailed drawing of a typical pivot discs;

FIG. 5 is a drawing of a carrier member assembly; and

FIG. 6 is a cutaway drawing of a typical carrier member assembly.

10

Description of the Preferred Embodiments

Braided articles of this invention are preferably made on an apparatus

that consists of a concave inner braiding surface 11) such as that shown in FIG.

1. The braiding surface consists of movable segments 20 which are capable

of rotation about an axis 30 through a desired arc of rotation. The concave

15 surface 10 can be any partial or full surface of rotation. The concave inner

surface 10 can of course consist of curved and flat portions. The segments 20

are supported and guided in their revolution by stationary guide rails 40.

Rotation of the individual segments 20 may be accomplished by hydraulic or

pneumatic actuators, electric motors or other conventional mechanisms which

20 may be located at any convenient location such as between the guide rail 40

and the convex surface of the braiding segment 20. Pivot discs 50 are situated

on the concave surfaces of the braiding segments 20. The shape of the

braiding surface 10, the mobility of the braiding segments 20 and the individual

control of carrier members 150 facilitates the unique placement of fibers that

25 heretofore has been unattainable except by manual manipulation of yarns, as

discussed below.

The end view of the braiding apparatus shown in FIG. 2 illustrates

various positions of the segments 20 on the guide rail 40 in relation to the

braiding zone 60 formed by the fiber strands of the article 80 being braided.

30 Guide rings 45 secure the segments 20 on the guide rails 40. Guide
LAR 14047-1 -4- PATENT APPLICATION

mechanisms 25 such as a grooved wheel are powered by a motor 28, fixedly

connected to movable segments 20, and travel along guide rails 40. The motor

is powered by a power supply 216 controlled by a computer 215 in the same

manner as shown in FIG. 1.

5 FIG. 3 illustrates the layout of evenly spaced, non-translating pivot discs

50 on the concave surface of the braiding segments 20. The braiding surface

20 consists of an assemblage of pivot discs 50. Along the flat or singularly

curved regions of the braiding segments 20 the pivot discs 50 are evenly

spaced. However, on the region of the braiding surface 10 with double

10 curvature some of the rows of pivot discs 50 are omitted. Deleting rows along

the doubly curved region of the braiding surface 10 limits the amount of

movement between rows that is capable in this region. Each pivot discs 50 is

capable of rotation through ±180 ° about its center point, i.e., about an axis

perpendicular to the concave side of the braiding surface 21} as discussed

15 below. Situated on the pivot discs 50 are linear shafts 90 which can be

longitudinally aligned with similar shafts 90 on adjacent pivot discs 50 by

rotation of the discs 50. Non-braiding yarn tubes 75 extend through the

braiding segments 20 between the pivot discs 50 to guide unidirectional nonbraiding fibers 77 for the braided article 80. By extending these yarns through

20 the braiding surface, the need for separate tractor/yarn carriers for these yarns

is eliminated, thereby further reducing the required braiding area.

FIG. 4 shows additional details of a pivot disc 50. The surface of the disc

50 has electrical power and sensor contact strips 110. The linear shaft 90 is

flanked by shaft gears 120 which are used to facilitate movement of carrier

25 members 150 discussed below. Below the pivot disc 50 is a stationary support

disk 130 which houses a conventional stepper motor or rotary solenoid 135

which turns the pivot disc 50.

FIG. 5 illustrates a carrier member 150 which travels on the concave

side of the braiding surface 10 from pivot disc 50 to pivot disc 50. The carrier

30 member 150 consists of a yarn carrier 160, which dispenses a fiber strand 70,
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LAR 14047-1 -5- PATENT APPLICATION

and a tractor assembly 170. The tractor assembly 170 has a linear motion

bearing 190 which guides the carrier member 150 on linear shafts 90.

Independent propulsion of each carder member 150 is accomplished by an

electric motor 180 which operates a drive gear 200 which intermeshes with

shaft gears 120. The motor 180 is powered through integral electrical power

and sensor contacts 210 and is controlled by a computer 215 through a power

supply 216. The computer 215 is programmed to activate power at the carder

members 150, yarn carders 160 and braid segments 20 in a sequence

determined by the braiding pattern required to construct a given article. When

power is turned on at a pivot point electrical current goes from the pivot point

through the electrical contacts 110 and 210 and to the motor 180 on the carder

member 150. The shaft of the motor turns the gears in the gear head

assembly and the drive gears 200. The drive gears 200 mesh with the rack

gears 120 on the pivot disc 50. When the drive gears 200 turn the carder

member 150 moves.

Referring to FIG. 3, three different carrier member 150 movements are

possible; a carrier member 150 (not shown in FIG. 3) located on pivot disc 50A

may advance forward to pivot disc 50B, turn to the left or right and advance to

pivot disc 50D or 50E, and turn "1800 and advance to the pivot disc 50C behind

the original location. To advance forward to the next pivot disc 50B the

computer 215 must turn on the electrical power at the first pivot disc 50A. The

carder member 150 moves forward onto the next pivot disc 50B until the

electrical contacts 210 of the carder member 150 no longer make contact with

the contacts 110 on the first pivot disc 50A. The computer 215, through

monitoring the current levels on the first pivot disc 50A, turns the power off at

the first pivot disc 50A and turns on the power at the second pivot disc 50B.

Once the carrier member 150 is completely on the second pivot disc 50B the

computer 215 turns off the power at the second pivot disc 50B.

To move the carder member 150 to the pivot discs 50D or 50E to the

right or left of the original pivot disc 50A, it is first necessary to rotate both pivot
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LAR 14047-1 -6- PATENT APPLICATION

discs 50A and 50D or 50A and 50E 90° so that the longitudinal axes of

horizontal shafts 90 mounted on the pivot discs 50A and 50D or 50A and 50E

line up with each other. It is important to insure that the pivot discs 50 are

rotated in phase so that the carrier member 150 will not be facing the wrong

direction after the transfer is complete. The computer 215 turns the electrical

power on at the first pivot disc 50A and the carrier member 150 advances to

the designated second pivot disc 50D or 50E. When electrical contact no longer

exists between the first pivot disc 50A and the carrier member 150, the

computer 215 turns the electrical power off at the first pivot disc 50A and on at

the second designated pivot disc 50D or 50E. Once the carrier member 150

is positioned correctly on the second pivot disc 50D or 50E, the computer 215

reorients both pivot discs 50A and 50D or 50E.

In the third case the computer 215 rotates the first pivot disc 50A 180 °

and the carrier member 150 advances to the second pivot disc 50C in a similar

manner as is done in the other cases. After the carrier member 150 is correctly

positioned onto the second pivot disc 50C, the computer 215 reorients the first

pivot disc 50A.

FIG. 6 illustrates a yarn carrier 160 which is mounted on the top of a

carrier member 150 and dispenses a braiding fiber strand 70. The fiber 70 is

wound on a spool 220 prior to the mounting of the yarn carrier 160 onto the

carrier member 150. Yarn 70 is pulled from the yarn carrier 160 as the carrier

member 150 is moved around the braiding surface 10. Tension is maintained

in the yarn 70 to eliminate the beat up process by incorporating a friction

coupling 230 and a rewind mechanism 240. An electric motor or coil spring

240 may be used to rewind the fiber 70. As the yarn 70 is being pulled out of

the carrier 160 the coil spring 240 has already been contracted to its limit.

Therefore, tension increases in the yarn 70 until the torque on the spool 220

exceeds the resisting torque supplied by the friction coupling 230. The yarn 70

is then pulled out of the carrier 160 when the tension in the yarn 70 exceeds

the resisting force supplied by the friction coupling 230. During the braiding
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LAR 14047-1 -7- PATENT APPLICATION

operation there are times when a movement of the carrier member 150 does

not result in the extraction of yarn 70 from the carrier 160. Therefore, to

maintain tension in the yarn 70 a rewind mechanism must exist and hence the

coiled spring 240. The coiled spring 240 rewinds the yarn 70 when the tension

in the yarn 70 diminishes.

In order to maintain a constant distance between the braiding zone 60

and the braiding surface 10 and to maintain tension of the braiding yarns 70,

a material takeup system 85 is required. Maintaining a constant distance

between the braiding zone 60 and the braiding surface 10 permits accurate

control of yarn braid angles. Differing preform geometries require different

customized takeup systems. Referring to Fig. 7, if a flat preform 81) is being

braided a clamp 260 secures the top of the preform 80 and a simple set of

tension rollers 270 advances the preform 80. As the preform 80 is braided the

tension rollers 270 periodically rotate, in accordance with the braid length, and

advance the material. However, if a curved I-beam is braided then the takeup

system (not shown) would consist of a series of small movable tension rollers

that advance the outer surface of the I-beam at a faster rate than the inner

surface of the I-beam.

The programming required to achieve the desired movements of the

segments 20, pivot discs 50 and the carrier members 150 is specifically tailored

to the particular braiding pattern. The functions described above define the

range of motion for each element and specific operating parameters are

implemented straightforwardly.

The computer 215 also controls the position of the movable braiding

segments 20. Certain yarns may be used as "fill" (90 degree) yarns 77 and it

may be necessary for the braiding segments 20 to be rotated to facilitate the

insertion of the fill yarn 77. There are other potential examples where the

braiding segments 20 must be moved. It is possible that the braiding segments

20 may be rotated such that the carrier members 150 are inverted.
LAR 14047-1 -8- PATENT APPLICATION

In the braiding process a fault condition could occur with one of the

carrier members 150 or yarn carriers 160. For example, one of the yarn

carriers 160 could have a yarn 70 breakage. A fault sensor (not shown) in the

yarn carrier 160 signals the computer 215 that a problem existed and the

5 computer 215 could stop the braiding process and signal the operator that a

fault condition existed. The computer 215 could, by a graphical means, show

which carder member 150 or yarn carrier 160 signaled the problem. The

operator would instruct the computer 215 to move the carrier member 150 to

a position where the problem could be corrected or the computer 215 could

10 rotate a braiding segment 21} and the operator manually correct the problem.

Even with the most sophisticated computers and state-of-the-art

electronics, the braiding of complex structural preforms will be a slow process.

The necessary fabrication efficiency will only be achievable when the entire

process of braiding is automated from the original design of the preform to the

15 final braiding of the preform. A designer from a Computer Aided Design (CAD)

station preferably designs the structural preform 80. Prior to braiding the

preform 80 the design undergoes computer braiding simulation to validate the

design. After the design has been validated, the appropriate number of yarn

carriers 160 are wound with yarn 70. Each yarn carder 160 contains a specific

20 amount of yarn 70 that is a function of the path the yarn travels in the braided

preform 80. Each yarn carrier 160 is bar coded and stored until the setup of

the braider commences. Each yarn carrier 160 is mounted to a carder member

150, sensors tested, yarn tension set and then moved onto the braider 20. The

computer 215 directs the movement of the carrier member 150 (as discussed

25 above) to the correct starting pivot disc 50 on the braider surface 20. A robotic

arm (not shown) extracts the end of the yarn 70 from the cap of the yarn carder

160 and mounts it onto the material takeup system 85. The process of

positioning carrier members 150 and mounting the yarn ends 70 onto the

material takeup system 85 is repeated until all the carder 150 members are

30 correctly positioned onto the braider 20. When nonbraiding yarns 77 are used
LAR 14047-1 -9- PATENT APPLICATION

in a preform design the operator inserts these yarns 77 through the appropriate

yarn tubes 75 on the braiding surface 20 and the robotic arm attaches the yarn

ends 77 to the material takeup system 85.

Once the braider has been strung the braiding begins. While a preform

5 80 is being braided additional yarn carriers 160 are being wound with yarn 70,

bar coded and stored for the next preform.

Many improvements, modifications and substitutions will be apparent to

the skilled artisan without departing from the spirit and scope of the present

invention as described herein and defined in the following claims.
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LAR 14047-1 PATENT APPLICATION

METHOD AND APPARATUS FOR THREE DIMENSIONAL BRAIDING

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Abstract of the Disclosure

A machine for three-dimensional braiding of fibers is provided in which

carrier members travel on a curved, segmented and movable braiding surface.

The carrier members are capable of independent, self-propelled motion along

the braiding surface. Carrier member position on the braiding surface is

controlled and monitored by computer. Also disclosed is a yarn take-up device

capable of maintaining tension in the braiding fiber.
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