Patent US4133155A successfully refreshed from Google Patents.
US4133155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Joist structure
Assignee: Individual
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Filing: 1977-06-29
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Granted: 1979-01-09
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Expires: 1997-06-29
Abstract
Abstract A joist structure having a configuration useful for constructing concrete-forming structures. The joist is comprised of an upwardly opening channel and an oppositely facing downwardly opening keyhole-shaped channel. The joist is an extruded elongate member having the respective channel end walls abutting each other. The upwardly facing channel has a generally rectangular form with the side walls being considerably wider than the end walls to accommodate standard wooden beam sizes, such as a 2 × 4. The downwardly facing channel, somewhat narrower and shorter than the upwardly facing channel, has a keyhole shape which considerably increases the compressive and torsion strength of the overall joist. The keyhole shape also accommodates keyhole-shaped inserts for strengthening the joist at high stress points, such as bearing surfaces and the mid-point between spans. The keyhole-shaped inserts can be provided in varying lengths according to the need and can incorporate mounting holes for the joist.
Inventors
- 👤 Lee D. Oelrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:47
CPC Classifications
E; E04; E04C; E04C3/00; E04C3/02; E04C3/29; E04C3/292; E04G; E04G11/00; E04G11/36; E04G11/48; E04G11/50; E04G17/00; E04G17/04; E04G17/042; E04G17/14; E04G2011/505
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
100 words
Joist for concrete forms and the like comprising: an elongate beam comprising a pair of outward facing, opposite channels having a common end wall; one of said channels having a cross-section in the form of a keyhole having a substantially circular upper portion ending in a pair of inwardly extending curved ridges and then extending downward to terminate in a pair of opposite inwardly extending shoulders; the other of said channels being of rectangular cross-section whereby an elongate wooden nailer may be located in said other channel thereby to provide a mounting surface for nailing a concrete form sheet thereto.
Claim 2
Dependent Claim
100 words
Joist for concrete forms and the like comprising: an elongate beam comprising a pair of outward facing, opposite channels having a common end wall; one of said channels having a cross-section in the form of a keyhole having a substantially circular upper portion ending in a pair of inwardly extending curved ridges and then extending downward to terminate in a pair of opposite inwardly extending shoulders; the other of said channels being of rectangular cross-section whereby an elongate wooden nailer may be located in said other channel thereby to provide a mounting surface for nailing a concrete form sheet thereto.
Claim 3
Dependent Claim
39 words
Joist according to claim 1 including: outwardly extending flanges along each side of said outward facing opposite channels; said flanges having a rolled lip along their outermost edge for engaging clips to clamp said joist securely to a structure.
Claim 4
Dependent Claim
41 words
Joist in accordance with claim 1 including at least one elongate strengthening insert having a cross-section the same as that of said one channel, positioned in said one channel, and having a length substantially less than the length of said beam.
Claim 5
Dependent Claim
27 words
The joist structure according to claim 3 wherein said keyhole-shaped strengthening inserts have threaded holes for securing said beam to a truss for constructing a concrete form.
Claim 6
Dependent Claim
26 words
The joist structure according to claim 3 wherein said keyhole-shaped strengthening inserts have one or more slotted, projecting tongues for securing said beams with a wedge.
Claim 7
Dependent Claim
23 words
The joist structure according to claim 1 wherein the rectangular-shaped channel has a side wall to end wall width ratio of approximately 2.
Claim 8
Dependent Claim
26 words
The joist structure according to claim 6 wherein the rectangular-shaped channel has side wall and end wall dimensions approximately equal to a standard 2 × 4.
Claim 9
Dependent Claim
64 words
A concrete construction form comprising: a plurality of joists according to claim 1 arranged parallel at a predetermined spacing; wooden filler means filling said rectangular-shaped channel; wooden forming means supported on said joists and secured by nailing to said filler; a pair of trusses transversely supporting opposite ends of said joists; fastening means fastening said joists to said trusses thereby forming a concrete-forming structure.
Claim 10
Dependent Claim
46 words
The concrete construction form according to claim 8 including: elongate strengthening inserts having a cross-section the same as that of said one channel, positioned in said one channel at the truss contact bearing points and having a length substantially less than the length of said beam.
Claim 11
Dependent Claim
48 words
The concrete construction form according to claim 9 wherein said fastening means comprises: threaded bolt holes in said keyhole-shaped means spanning said truss; clamping means clamped around said truss and bolted to said threaded holes in said keyhole-shaped means to secure each of said joists to said truss.
Claim 12
Dependent Claim
107 words
The concrete construction form according to claim 9 wherein said trusses comprise inverted joists having an elongate beam comprising a pair of outward facing, opposite channels having a common end wall; one of said channels having a cross-section in the form of a keyhole having a substantially circular upper portion ending in a pair of inwardly extending curved ridges and then extending downward to terminate in a pair of opposite inwardly extending shoulders; the other of said channels being of rectangular cross-section whereby an elongate wooden nailer may be located in said other channel thereby to provide a mounting surface for nailing a concrete form sheet thereto.
Claim 13
Dependent Claim
51 words
The concrete construction form according to claim 11 including: elongate strengthening inserts having a cross-section the same as that of said one channel positioned in said one channel of said trusses at the contact bearing point of said joists and having a length substantially less than the length of said beam.
Claim 14
Dependent Claim
37 words
The concrete construction form according to claim 9 wherein said fastening means comprises: threaded bolt holes in said keyhole-shaped means on either side of said joist; clamping means bolted to said trusses for clamping said joist securely.
References Cited (Backward Citations)
US2182015A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-08 | 1982-07-10 | 1983-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-08 | 1986-07-10 | 1987-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-08 | 1990-07-10 | 1991-01-09 | $7700.00 | Window Closed / Lapsed |