US5154371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Main rotor assembly support truss
Assignee: RTX Corp
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Filing: 1991-04-10
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Granted: 1992-10-13
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Expires: 2011-04-10
Abstract
Abstract A support truss for the main rotor assembly of a helicopter is configured to structurally support the main rotor assembly in integrated combination with the helicopter airframe and to transmit dynamic and static longitudinal, lateral, vertical, and torsional loads of the main rotor assembly into the helicopter airframe at two distinct, spaced-apart load transfer levels. The support truss is an integrally formed structure that includes a generally cylindrical body member configured to provide attachment points for the static rotor mast and the transmission of the main rotor assembly, a pair of forward facing primary support ribs configured to secure the support truss to a primary load transfer level of the helicopter airframe and to transmit dynamic and static longitudinal, lateral, vertical, and all torsional loads to the primary load transfer level, and a pair of aft facing support struts configured to secure the support truss to a secondary load transfer level and to transmit only axial loads to the secondary transfer level. The support truss also includes a forward facing secondary support rib that provides fail-safe redundancy in the event of a loss of one of the primary support ribs. The support truss may also include a cross stringer extending between and integrally interconnecting the primary and secondary support ribs. A plurality of servo lugs may be integrally formed with the body member to provide lower attachment points for rotor servo actuators of the main rotor assembly.
Inventors
- 👤 Peter L. Grant
- 👤 Darryl M. Toni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:51
CPC Classifications
B; B64; B64C; B64C1/00; B64C1/16; B64C27/00; B64C27/001; B64C27/04; B64C27/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
250 words
For a helicopter having a main rotor assembly that develops dynamic and static longitudinal, lateral, vertical, and torsional loads, a transmission, and an airframe that includes a gusset structure and a transmission deck, a main rotor assembly support truss, comprising: body member means configured for supporting the main rotor assembly in integrated combination with the helicopter airframe, said body member means including means for securing the transmission in suspended combination with said main rotor assembly support truss; first and second parallel, spaced apart forward facing support ribs integral with said body member means and including means for securing said first and second forward facing support ribs to the gusset structure, said first and second forward facing support ribs provide a shear attachment for said main rotor assembly support truss and are configured and sized for transmitting the dynamic and static longitudinal, lateral, vertical, and all torsional loads of the main rotor assembly to the gusset structure that functions as a primary load transfer plane of the helicopter airframe; and first and second spaced apart aftwardly extending support struts integral with said body member means and including means for securing said first and second aftwardly extending support struts to the transmission deck, said first and second aftwardly extending support struts provide a tension attachment for said main rotor assembly support truss and are configured and sized for transmitting axial loads of the main rotor assembly to the transmission deck that functions as a secondary load transfer plane of the helicopter airframe.
Claim 2
Dependent Claim
250 words
For a helicopter having a main rotor assembly that develops dynamic and static longitudinal, lateral, vertical, and torsional loads, a transmission, and an airframe that includes a gusset structure and a transmission deck, a main rotor assembly support truss, comprising: body member means configured for supporting the main rotor assembly in integrated combination with the helicopter airframe, said body member means including means for securing the transmission in suspended combination with said main rotor assembly support truss; first and second parallel, spaced apart forward facing support ribs integral with said body member means and including means for securing said first and second forward facing support ribs to the gusset structure, said first and second forward facing support ribs provide a shear attachment for said main rotor assembly support truss and are configured and sized for transmitting the dynamic and static longitudinal, lateral, vertical, and all torsional loads of the main rotor assembly to the gusset structure that functions as a primary load transfer plane of the helicopter airframe; and first and second spaced apart aftwardly extending support struts integral with said body member means and including means for securing said first and second aftwardly extending support struts to the transmission deck, said first and second aftwardly extending support struts provide a tension attachment for said main rotor assembly support truss and are configured and sized for transmitting axial loads of the main rotor assembly to the transmission deck that functions as a secondary load transfer plane of the helicopter airframe.
Claim 3
Dependent Claim
37 words
The main rotor assembly support truss of claim 1 wherein said body member means further includes lug means integral with said body means for providing lower attachment points for rotor servo actuators of the main rotor assembly.
Claim 4
Dependent Claim
42 words
The main rotor assembly support truss of claim 1 wherein said body member means, said first means and said second means are formed from an electrically conductive metallic material and function as an electrical ground bus for electrical subsystems of the helicopter.
Claim 5
Dependent Claim
19 words
The main rotor assembly support truss of claim 3 wherein said electrically conductive metallic material is an aluminum alloy.
Claim 6
Dependent Claim
38 words
The main rotor assembly support truss of claim 1 wherein said securing means of said body member means is a lower flange attachment means for securing the transmission in suspended combination with said main rotor assembly support truss.
Claim 7
Dependent Claim
46 words
The main rotor assembly support truss of claim 1 wherein the main rotor assembly includes a static rotor mast and said body member means further includes an upper flange attachment means for securing the static rotor mast in combination with said main rotor assembly support truss.
Claim 8
Dependent Claim
44 words
The main rotor assembly support truss of claim 1 wherein said securing means of each said first and second parallel, spaced apart primary support ribs is an attachment foot for securing said respective forward facing primary support rib to said primary load transfer plane.
Claim 9
Dependent Claim
93 words
The main rotor assembly support truss of claim 7 further comprising a secondary forward facing support rib integral with said body member means and disposed intermediate said first and second primary support ribs in parallel, spaced apart relation therewith, said secondary forward facing support rib having an attachment foot for securing said secondary forward facing support rib to said primary load transfer plane, and wherein said secondary forward facing support rib is configured and sized to provide fail-safe redundancy if one of said parallel, spaced apart forward facing primary support ribs is lost.
Claim 10
Dependent Claim
38 words
The main rotor assembly support truss of claim 8 further comprising a cross stringer extending transversely between and interconnecting said parallel, spaced apart first and second forward facing primary support ribs and said secondary forward facing support rib.
Claim 11
Dependent Claim
41 words
The main rotor assembly support truss of claim 1 wherein said securing means of each said first and second aftwardly facing support struts is an attachment foot for securing said respective aftwardly facing support struts to said secondary load transfer plane.
Claim 12
Dependent Claim
46 words
The main rotor assembly support truss of claim 10 wherein said first and second aftwardly facing support struts are further operative to buckle in compression in the event of a helicopter crash exceeding worst case design loads to cause the main rotor assembly to rotate aftwardly.
Claim 13
Dependent Claim
18 words
The main rotor assembly support truss of claim 1 wherein said body member means has a cylindrical configuration.
Claim 14
Dependent Claim
38 words
The main rotor assembly support truss of claim 12 wherein said securing means of said cylindrical body member is a lower flange attachment configured for securing the transmission in suspended combination with said main rotor assembly support truss.
Claim 15
Dependent Claim
46 words
The main rotor assembly support truss of claim 12 wherein the main rotor assembly includes a static rotor mast and wherein said cylindrical body member includes an upper flange attachment configured for securing the static rotor mast in combination with said main rotor assembly support truss.
Claim 16
Dependent Claim
34 words
The main rotor assembly support truss of claim 12 wherein said cylindrical body member includes three spaced apart servo lugs operative as lower attachment points for rotor servo actuators of the main rotor assembly.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-13 | 1996-04-13 | 1996-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-13 | 2000-04-13 | 2000-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-13 | 2004-04-13 | 2004-10-13 | $7700.00 | Window Closed / Lapsed |