US4364987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fire door construction
Assignee: BC MILLWORK Ltd A Co OF BRITISH COLUMBIA
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Filing: 1981-08-27
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Granted: 1982-12-21
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Expires: 2001-08-27
Abstract
Abstract This invention discloses a core for a fire-resistant door with wooden stiles and rails forming the peripheral edge and a slab filling the space therebetween comprising a cured mixture of magnesium oxi-chloride with inclusions of fibreglass strands and perlite. Also disclosed is a method of making same in which the wooden stiles and rails form the sides of a mold and the core is formed by pouring a mixture on a flat surface with a non-adhering coating and curing the core in place so that it bonds to the stiles and rails.
Inventors
- 👤 Walter A. Goodwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:55
CPC Classifications
E; E06; E06B; E06B5/00; E06B5/10; E06B5/16; C; C04; C04B; C04B28/00; C04B28/30; C04B28/32; C04B2111/00; C04B2111/20; C04B2111/28; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/91; Y10; Y10T; Y10T428/00; Y10T428/23; Y10T428/233; Y10T428/237; Y10T428/24; Y10T428/24777; Y10T428/249921; Y10T428/249953; Y10T428/249986
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
50 words
A core for a fire-resistant door comprising wooden stiles and rails forming the peripheral edges of said core; a slab filling the space between the surfaces of and surrounded by said stiles and rails; said slab comprising a cured mixture of magnesium oxy-chloride containing inclusions of fibreglass strands, and perlite.
Claim 2
Dependent Claim
50 words
A core for a fire-resistant door comprising wooden stiles and rails forming the peripheral edges of said core; a slab filling the space between the surfaces of and surrounded by said stiles and rails; said slab comprising a cured mixture of magnesium oxy-chloride containing inclusions of fibreglass strands, and perlite.
Claim 3
Dependent Claim
43 words
A core for a fire-resistant door as claimed in claim 1 in which said slab has a border portion adjacent said stiles and rails composed of a cured mixture of magnesium oxy-chloride containing fibreglass strands and approximately 80% by volume of wood chips.
Claim 4
Dependent Claim
42 words
A fire-resistant core as claimed in claim 1 in which said mixture comprises approximately 52 pounds of magnesium chloride flakes, 13 gallons of water, 30 pounds of magnesium chloride, 2.5 cubic feet of granulated perlite, and 624 grams of chopped fibreglass strands.
Claim 5
Dependent Claim
56 words
A fire-resistant core as claimed in claim 3 in which said slab has a border portion adjacent said stiles and rails composed of a cured mixture comprising approximately 52 pounds of magnesium chloride flakes, 13 gallons of water, 30 pounds of magnesium oxide, 624 grams of fibreglass chopped strands and 80% by volume of wood chips.
Claim 6
Independent Claim
85 words
A method of making a fire-resistant door core comprising the steps of forming a rectangular frame of stiles and rails; fastening a sheet of planar material to the underside of said frame to provide a bottom to a mold formed by the cavity surrounded by said frame stiles and rails; pouring a mixture of material curable to form a core slab in the cavity formed by said frame; allowing said material to cure and bond to said stiles and rails to form an inner panel.
Claim 7
Independent Claim
85 words
A method of making a fire-resistant door core comprising the steps of forming a rectangular frame of stiles and rails; fastening a sheet of planar material to the underside of said frame to provide a bottom to a mold formed by the cavity surrounded by said frame stiles and rails; pouring a mixture of material curable to form a core slab in the cavity formed by said frame; allowing said material to cure and bond to said stiles and rails to form an inner panel.
Claim 8
Dependent Claim
20 words
A method as claimed in claim 5 in which said stiff sheet is overlain by a layer of non-adhering material.
Claim 9
Dependent Claim
16 words
A method as claimed in claim 6 in which said stiff planar sheet is perforated pegboard.
Claim 10
Dependent Claim
85 words
A method as claimed in claim 5 including the steps of placing inserts along the inner side of the stiles and rails and removing said inserts after said core material has harden sufficient to resist slumping; filling the space vacated by the inserts with a material curable to form a border of dense material comprising magnesium oxy-chloride with inclusion of wood chips comprising 80% by volume; allowing said core slab material to cure during the exothermic stage at approximately 70° F. at approximately 50% humidity.
Claim 11
Dependent Claim
35 words
The method as claimed in claim 8 including the steps of further curing the core by placing same in an atmosphere of approximately 125° F. and less than 10% humidity for an additional 6 hours.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-12-20 | 1986-06-21 | 1986-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-20 | 1990-06-21 | 1990-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-20 | 1994-06-21 | 1994-12-21 | $7700.00 | Window Closed / Lapsed |