Skin-bonded threaded inserts, sandwich panels including the same, and related methods

Patent metadata

Field	Value
Publication number	US-11850810-B2
Application number	US-202217726972-A
Country	US
Kind code	B2
Filing date	Apr 22, 2022
Priority date	May 18, 2021
Publication date	Dec 26, 2023
Grant date	Dec 26, 2023

Abstract

Skin-bonded threaded inserts may be installed within a sandwich panel by curing the insert in place as the sandwich panel is cured. Skin-bonded threaded inserts may include a collar that is transitioned between a raised position and a compressed position during installation of the skin-bonded threaded insert in the sandwich panel, due to compression of the sandwich panel during curing. Skin-bonded threaded inserts may include one or more flanges that engage one or more skins of the sandwich panel. Such flanges may be positioned between two skins, or between the core and a skin of the sandwich panel to secure the sandwich panel in place within the sandwich panel. Skin-bonded threaded inserts may be positioned within a sandwich panel without the use of potting compound and may engage with the skins of the sandwich panel, rather than relying on adherence to the core for sufficient pull-out and shear strength.

First claim

The invention claimed is:

1. A skin-bonded threaded insert configured to be installed in a bore of a sandwich panel, the sandwich panel comprising a first skin, a second skin opposite the first skin, and a core therebetween; the skin-bonded threaded insert comprising:
a main body configured to extend longitudinally through at least part of the core of the sandwich panel from a first transverse face of the main body to a second transverse face of the main body, wherein an exterior circumferential surface of the main body is configured to engage the core of the sandwich panel when the skin-bonded threaded insert is installed in the sandwich panel wherein the main body is a monolithic main body, and wherein the main body comprises a hole extending longitudinally through at least a portion of the main body, the hole comprising:
a threaded portion that is threaded such that it is configured to engage a fastener, wherein the threaded portion extends longitudinally along at least a portion of a length of the hole in a longitudinal direction, and wherein the threaded portion has a major diameter corresponding to a maximum diameter of the threaded portion;
a first enlarged portion having an enlarged diameter that is greater than the major diameter of the threaded portion; and
a shelf formed at a transition between the first enlarged portion and the threaded portion; and

a collar that is sized with respect to the first enlarged portion of the hole such that an external surface of the collar has a friction fit with the first enlarged portion, wherein the collar is configured to be longitudinally translated with respect to the main body, to transition the collar between a raised position and a compressed position during installation of the skin-bonded threaded insert in the sandwich panel, wherein the collar is configured to be engaged with the first enlarged portion in both the raised position and the compressed position.

2. The skin-bonded threaded insert according to claim 1 , wherein the first transverse face of the main body engages with the first skin.

3. The skin-bonded threaded insert according to claim 1 , wherein in the raised position, a lower surface of the collar is positioned such that it is facing and spaced apart from the shelf of the hole by a collar displacement distance.

4. The skin-bonded threaded insert according to claim 3 , wherein in the compressed position, the collar displacement distance is less than when the collar is in the raised position, such that the lower surface of the collar is closer to the shelf when the collar is in the compressed position than when the collar is in the raised position.

5. The skin-bonded threaded insert according to claim 1 , further comprising a thermoset resin coating on the first transverse face, the second transverse face, and the exterior circumferential surface of the main body, wherein the thermoset resin is configured to flow during curing of the sandwich panel, to bond the skin-bonded threaded insert within the sandwich panel.

6. The skin-bonded threaded insert according to claim 1 , wherein the first transverse face and the second transverse face of the main body are knurled.

7. The skin-bonded threaded insert according to claim 1 , wherein the collar is configured to be transitioned to the compressed position when the sandwich panel is compressed, such that the sandwich panel and the skin-bonded threaded insert are compressed together.

8. The skin-bonded threaded insert according to claim 1 , wherein an upper surface of the collar is at least substantially flush with the second skin when the collar is in the compressed position, wherein the upper surface of the collar is opposite a lower surface of the collar, and wherein the upper surface of the collar sits proud of the second skin when the collar is in the raised position.

9. The skin-bonded threaded insert according to claim 1 , wherein the skin-bonded threaded insert is configured to be bonded to the sandwich panel within the bore of the sandwich panel concurrently with bonding of the first skin, the second skin, and the core of the sandwich panel.

10. The skin-bonded threaded insert according to claim 1 , wherein the hole further comprises a second enlarged portion having a second enlarged diameter that is greater than the major diameter of the threaded portion, wherein the hole comprises a second shelf formed at a second transition between the second enlarged portion and the threaded portion, and wherein the skin-bonded threaded insert further comprises a second collar that is sized with respect to the second enlarged portion of the hole such that a second external surface of the second collar has a friction fit with the second enlarged portion, wherein the second collar is configured to be transitioned between a second raised position and a second compressed position during installation of the skin-bonded threaded insert in the sandwich panel, wherein in the second raised position, a second lower surface of the second collar is positioned such that it is spaced apart from the second shelf of the hole, and wherein in the second compressed position, the second lower surface of the second collar is engaged with the second shelf of the hole.

11. The skin-bonded threaded insert according to claim 1 , further comprising a floating threaded nut positioned within the hole of the skin-bonded threaded insert.

12. The skin-bonded threaded insert according to claim 1 , wherein the main body further comprises an enlarged flange that projects radially outward from the exterior circumferential surface, wherein the enlarged flange defines the first transverse face.

13. The skin-bonded threaded insert according to claim 1 , further comprising a second insert part configured to engage with the main body such that at least part of the main body is positioned within a receiving volume of the second insert part when the main body is engaged with the second insert part, wherein engagement between the main body and the second insert part is selectively adjustable to adjust an overall height of the main body together with the second insert part, wherein the second insert part comprises a second exterior circumferential surface configured to engage the core of the sandwich panel, a panel-engaging transverse surface configured to engage the first skin or the second skin of the sandwich panel, and an insert-facing transverse surface configured to engage the main body.

14. The skin-bonded threaded insert according to claim 13 , wherein the second insert part comprises internal threads to engage the exterior circumferential surface of the main body, wherein the second insert part is configured to engage with the main body such that compression of the sandwich panel and the collar causes longitudinal translation of the main body with respect to the second insert part, thereby reducing the overall height, and wherein the internal threads of the second insert part are configured to engage the main body such that the main body ratchets past the internal threads when the sandwich panel is compressed with sufficient force, thereby longitudinally translating the main body with respect to the second insert part, and thereby reducing the overall height.

15. A method of installing the skin-bonded threaded insert according to claim 1 into the sandwich panel, the method comprising:
preparing the first skin, where in the preparing comprises ultrasonic cutting to shape the first skin of the sandwich panel;
positioning the core of the sandwich panel on the first skin such that a first face of the core faces the first skin;
forming the bore in the core of the s

Assignees

• Boeing Co

Inventors

• Wirrick Jeffrey Thomas Ikaika

Classifications

• B29C70/682 Primary

  Preformed parts characterised by their structure, e.g. form · CPC title

• B29C70/683

  Pretreatment of the preformed part, e.g. insert · CPC title

• B29C70/685

  by laminating inserts between two plastic films or plates · CPC title

• B29C2793/0027

  Cutting off · CPC title

• B29K2101/10

  Thermosetting resins · CPC title