# US 12,179,439 B2 · Apparatus and method for applying an elongate fiber tow

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- Number: US 12,179,439 B2
- Document ID: US12179439B2
- Status: Granted
- Kind: B2
- Application number: 17/789,419
- Filed: 2021-01-04
- Published: 2023-02-16
- Granted: 2024-12-31
- Earliest claimed: 2020-01-02
- Assignees: 9T Labs AG
- Applicants: 9T Labs AG
- Inventors: Leo Baumann; Lucien Segessemann; Chester Houwink; Martin Eichenhofer; Giovanni Cavolina
- Web page: https://patentgrep.com/patent/US12179439B2

## CPC

- B29C 64/236: for motion in a direction within the plane of a layer
- B29C 70/34: and shaping or impregnating by compression {, i.e. combined with compressing after the lay-up operation}
- B29C 64/118: using filamentary material being melted, e.g. fused deposition modelling [FDM]
- B29C 64/209: Heads; Nozzles
- B29C 70/384: {Fiber placement heads, e.g. component parts, details or accessories}
- B29C 70/388: {Tape placement heads, e.g. component parts, details or accessories}
- B29C 70/545: {Perforating, cutting or machining during or after moulding}
- B29C 70/38: Automated lay-up, e.g. using robots, laying filaments according to predetermined patterns {(application heads for tyres B29D30/28)}
- B29C 70/386: {Automated tape laying [ATL]}
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)

## Abstract

A pressure foot device and system comprising a pressure foot device for forming and applying an elongate fiber tow, wherein the pressure foot device comprises a foot surface comprising a straight foot segment, a groove comprising a flared end and defining a groove midplane, and a foot shaft housing characterized by a foot shaft's axis of rotation that is orthogonal to the straight foot segment and comprised in the groove midplane.

## Claims

### Claim 1

A pressure foot device for applying an elongate fiber tow onto an object surface, the device comprising:
a foot surface including a straight foot segment configured to press the fiber tow onto the object surface, the straight foot segment including a rear end and a front end that define a frontal direction from the rear end to the front end;
a groove including a left lip and a right lip configured to guide the fiber tow to the foot surface, the groove defining a groove midplane as a planar portion along a mid-line of the groove and extending between the left lip and the right lip of the groove, the groove joining onto the front end of the straight foot segment and oriented at an elevation angle with respect to the straight foot segment,
the groove including a flared end that joins the groove to the front end of the straight foot segment on the foot surface.

### Claim 2 (depends on 1)

The device of claim 1, wherein the foot surface includes:
a first toe surface at a first side of the groove midplane and oriented at a first elevation angle and a first azimuthal angle offset from the frontal direction; and
a second toe surface at a second side of the groove midplane and oriented at a second elevation angle and a second azimuthal angle offset from the frontal direction;
wherein the first azimuthal angle and the second azimuthal angle are included in a range from 30° to 90° with respect to the frontal direction.

### Claim 3 (depends on 1)

The device of claim 1, wherein the flared end includes a chamfer with an elevation angle in a range from 30° to 70° with respect to the frontal direction.

### Claim 4 (depends on 1)

The device of claim 1, wherein the device includes a hollow foot shaft to translate the fiber tow to the groove, an axis of which is located on the groove midplane.

### Claim 5 (depends on 1)

The device of claim 1, wherein the device includes a foot pinion, the axis of which is located on the groove midplane.

### Claim 6 (depends on 1)

The device of claim 1, wherein the foot surface includes, with respect to the front end, a first material within a first sector that is proximal to the front end and a second material within a second sector that is distal from the front end, wherein a thermal conductivity of the second material is at most half of a thermal conductivity of the first material.

### Claim 7 (depends on 1)

The device of claim 1, wherein the foot surface includes a heat sink.

### Claim 8 (depends on 1)

The pressure foot device of claim 1, the groove midplane extending between the left lip and the right lip of the groove until even with the left lip and the right lip in the frontal direction.

### Claim 9

A system for applying an elongate fiber tow onto an object surface, the system comprising:
a pressure foot device including:
a foot surface configured to press the fiber tow onto the object surface, the foot surface including a straight foot segment for pressing the fiber tow onto the object surface, the straight foot segment including a rear end and a front end that define a frontal direction from rear end to front end; and
a groove including a left lip and a right lip configured for guiding the fiber tow to the foot surface, the groove defining a groove midplane as a planar portion along a mid-line of the groove between the left lip and the right lip of the groove, the groove joining onto the front end of the straight foot segment and being oriented at an elevation angle with respect to the straight foot segment, the groove including a flared end that joins with the foot surface, wherein the pressure foot device includes a hollow foot shaft to translate the fiber tow to the groove, an axis of the hollow foot shaft located on the groove midplane; and
a foot shaft housing, characterized by the axis of rotation of the hollow foot shaft, defining a Z-axis, wherein the axis of rotation of the hollow foot shaft is orthogonal to the straight foot segment and is located in the groove midplane.

### Claim 10 (depends on 9)

The system of claim 9, wherein the axis of rotation of the hollow foot shaft is collinear with an axis of rotation of the foot shaft housing and wherein a portion of the hollow foot shaft forms a sliding fit within the foot shaft housing.

### Claim 11 (depends on 9)

The system of claim 9, wherein the foot shaft housing includes one or more sources of heat.

### Claim 12 (depends on 9)

The system of claim 9, further including one or more pinch roller assemblies and wherein one or more of the pinch roller assemblies includes a first roller and a second roller, wherein a tangent that is common to the first roller and to the second roller is collinear with the axis of rotation of the foot shaft.

### Claim 13

A method for applying an elongate fiber tow onto an object surface, the method comprising:
translating an elongate fiber tow through a hollow foot shaft into a groove of a pressure foot device unto a foot surface of the pressure foot device, the groove including a left lip, a right lip, and defining a groove midplane along a mid-line of the groove and extending between the left lip and the right lip of the groove, wherein an axis of the hollow foot is located on the groove midplane;
guiding the fiber tow within the groove to a flared end of the groove;
curving the fiber tow around the flared end of the groove to a straight foot segment included in the foot surface of the pressure foot device;
wherein the straight foot segment includes a rear end and a front end that define a frontal direction from the rear end to the front end, and
the groove joining onto the front end of the straight foot segment and being oriented at an elevation angle with respect to the straight foot segment; and
pressing the fiber tow between the straight foot segment and the object surface.

### Claim 14 (depends on 13)

The method of claim 13, wherein one or more of the steps of translating, guiding, curving, and pressing includes heating the fiber tow.

### Claim 15 (depends on 13)

The method of claim 13, wherein the step of pressing includes cooling the fiber tow.

### Claim 16 (depends on 13)

The method of claim 13, further including rotating the pressure foot device around an axis of rotation that is orthogonal to the straight foot segment and located within the groove midplane.

### Claim 17 (depends on 13)

The method of claim 13, further including one or more of translating and rotating the pressure foot device along a path from a path start to a path end;
wherein the straight foot segment is collinear with a tangent to the path of the pressure foot device and a point of tangency to the path is included within the groove midplane.

### Claim 18 (depends on 17)

The method of claim 17, wherein the fiber tow is translated within the groove at a speed equal to the speed at which the point of tangency to the path translates along the path.

### Claim 19 (depends on 17)

The method of claim 17, further including actuating a tow cutter assembly at a location along the path that is ahead of the path end by a path length equal to a length of fiber tow from a blade of the tow cutter assembly to the front end of the straight foot segment.

### Claim 20 (depends on 17)

The method of claim 17, further including unwinding the fiber tow wherein the step of unwinding includes rotating the pressure foot device.

### Claim 21 (depends on 13)

The method of claim 13, further comprising measuring a distance between the straight foot segment and the object surface.