IP Library Granted Patent US 12,442,245
Granted Patent B2
US 12,442,245 · App. 17/547,883 · Granted Oct 14, 2025

Laminated door core for use in fire rated doors and associated methods

Inventors: Lance Wasniewski (Ironton, MN); Andre Fortin (Hatley Township, CA)
Assignee: Lexington Manufacturing, LLC
E06B5/16B32B7/12B32B19/042B32B21/02B32B21/10B32B2250/05B32B2250/40B32B2262/101B32B2264/067B32B2307/3065B32B2419/00
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Quick Facts
Patent No.
US 12,442,245
App. No.
17/547,883
Granted
Oct 14, 2025
Kind
B2
Abstract

A laminated door core for use in fire rated doors includes a center layer having a first side and an opposing second side, where the center layer comprises fire rated particleboard. The laminated door core also includes a first layer comprising calcium silicate adhered to the first side of the center layer, a second layer comprising calcium silicate adhered to the second side of the center layer, a first layer of high-density fiberboard adhered over the first layer of calcium silicate, and a second layer of high-density fiberboard adhered over the second layer of calcium silicate. A vertical stile may be positioned along each opposing longitudinal edge of the laminated door core, and a horizontal rail may be positioned along each of a top end and a bottom end of the laminated door core.

Claims (27)

1. A fire rated door comprising:

a laminated door core, the laminated door core comprising,

a center layer having a first side and an opposing second side, the center layer comprising fire rated wood,

a first layer comprising a mineral material adhered to the first side of the center layer,

a second layer comprising the mineral material adhered to the second side of the center layer,

a first layer of high-density fiberboard adhered over the first layer of the mineral material, and

a second layer of high-density fiberboard adhered over the second layer of the mineral material;

wherein the center layer, the first layer of mineral material, and the second layer of mineral material each have approximately the same thickness.

2. The fire rated door of claim 1 , further comprising a vertical stile positioned along opposing longitudinal edges of the laminated door core.

3. The fire rated door of claim 2 , further comprising a horizontal rail positioned along opposing top and bottom ends of the laminated door core.

4. The fire rated door of claim 1 , wherein the mineral material comprises calcium silicate.

5. The fire rated door of claim 1 , wherein the mineral material comprises fiberglass.

6. The fire rated door of claim 1 , wherein the mineral material comprises gypsum.

7. The fire rated door of claim 3 , further comprising a first door skin adhered over the first layer of high-density fiberboard, and a second door skin adhered over the second layer of high-density fiberboard.

8. The fire rated door of claim 1 , wherein the fire rated wood comprises fire rated particleboard.

9. The fire rated door of claim 7 , further comprising a door jamb.

10. A laminated door core for a fire rated door, the laminated door core comprising:

a center layer having a first side and an opposing second side, the center layer comprising fire rated wood,

a first layer comprising a mineral material adhered to the first side of the center layer,

a second layer comprising the mineral material adhered to the second side of the center layer,

a first layer of high-density fiberboard adhered over the first layer of the mineral material, and

a second layer of high-density fiberboard adhered over the second layer of the mineral material;

wherein the center layer, the first layer of mineral material, and the second layer of mineral material each have approximately the same thickness.

11. The laminated door core of claim 10 , wherein the mineral material comprises calcium silicate.

12. The laminated door core of claim 10 , wherein the mineral material comprises fiberglass.

13. The laminated door core of claim 10 , wherein the mineral material comprises gypsum.

14. The laminated door core of claim 10 , wherein the fire rated wood comprises fire rated particleboard.

Assignments (2)
PATENT SECURITY AGREEMENT Recorded Nov 30, 2022
From: LEXINGTON MANUFACTURING, LLC
To: BANK OF AMERICA, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 062019/0479 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 13, 2021
From: WASNIEWSKI, LANCE; FORTIN, ANDRE
To: LEXINGTON MANUFACTURING LLC
Reel/Frame 058367/0886 →
Continuity (2)
Provisional Application 63124473 · Dec 11, 2020
Related Publication 20220186553A1 · Jun 16, 2022
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