US3889789A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal fuse mechanical disconnect
Assignee: McDonnell Douglas Corp
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Filing: 1974-04-15
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Granted: 1975-06-17
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Expires: 1994-04-15
Abstract
Abstract A rotary drive shaft disconnect mechanism which mechanically joins two aligned shafts and which disconnects them in response to the overheating of a component element. The mechanism generally comprises two axially aligned, abutting hollow cylindrical elements which are mounted for axial sliding in the driving and driven power shafts. The abutting ends of the cylinders are formed with matching teeth which are maintained in engagement by a preloaded compressive force. Suitable load carrying structure is provided within the cylinders so that a heat responsive fuse transfers the preload compressive force until such time as heat causes the fuse to fail. The fuse is comprised of multiple structural wires which are the elements thereof which transfer the compressive preload. The wires are enclosed in an eutectic matrix. The heat from an overheating component is transmitted to the eutectic which liquefies and removes the side support from the wires which then fail in a columnar bending mode, removing the load path for the compressive preload which allows the disconnection.
Inventors
- 👤 Wilfred E Boehringer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:36
CPC Classifications
F; F16; F16D; F16D9/00; F16D9/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
170 words
Torque disconnect means including: first means for connecting to torque supplying means; second means for connecting to torque receiving means; and third means for connecting and disconnecting said first and second means in torque transmitting relationship, said third means including bias means tending to force said first and second means to disconnect positions and a thermal fuse loaded in compression by said bias means, said thermal fuse including a body having opposite parallel abutment faces to which said bias means apply the compressive load, said thermal fuse body being constructed of fuse material which remains solid up to a predetermined temperature and a plurality of columnar supporting members which extend perpendicular to and between said abutment faces, whereby said fuse material prevents columnar bending of said supporting members until the predetermined temperature is reached, at which time the compressive load fails said supporting members in columnar bending so that said thermal fuse no longer resists said bias means, thereby allowing said bias means to disconnect said first and second means.
Claim 2
Dependent Claim
170 words
Torque disconnect means including: first means for connecting to torque supplying means; second means for connecting to torque receiving means; and third means for connecting and disconnecting said first and second means in torque transmitting relationship, said third means including bias means tending to force said first and second means to disconnect positions and a thermal fuse loaded in compression by said bias means, said thermal fuse including a body having opposite parallel abutment faces to which said bias means apply the compressive load, said thermal fuse body being constructed of fuse material which remains solid up to a predetermined temperature and a plurality of columnar supporting members which extend perpendicular to and between said abutment faces, whereby said fuse material prevents columnar bending of said supporting members until the predetermined temperature is reached, at which time the compressive load fails said supporting members in columnar bending so that said thermal fuse no longer resists said bias means, thereby allowing said bias means to disconnect said first and second means.
Claim 3
Dependent Claim
81 words
The torque disconnect means defined in claim 1 wherein said thermal fuse body includes: an inner cylindrical surface defining a bore therethrough, and said third means include: a shaft having opposite ends, said shaft extending through the bore in said thermal fuse body and connected at an end thereof to said first means; and an abutment member connected on the opposite end of said shaft, said abutment member abutting one of said thermal fuse faces to apply the compressive load thereto.
Claim 4
Dependent Claim
32 words
The torque disconnect means defined in claim 2 wherein said second means include: an abutment surface for abutment with the other of said thermal fuse faces to apply the compressive load thereto.
Claim 5
Dependent Claim
74 words
The torque disconnect means defined in claim 3 wherein said third means include: curvical gear teeth on said first means facing said second means; and curvical gear teeth on said second means facing said first means, said curvical gear teeth having maTing shapes and being maintained in engagement by the compresive load, said curvical gear teeth being shaped to generate additional compressive load when torque is being transmitted between said first and second means.
Claim 6
Dependent Claim
30 words
The torque disconnect means defined in claim 4 wherein said bias means include: a spring compressed between said first and second means tending to force said curvical gear teeth apart.
Claim 7
Dependent Claim
41 words
The torque disconnect means defined in claim 5 wherein said abutment member is in heat transfer relationship with the torque receiving means, whereby the heat in the torque receiving means is transferred to the thermal fuse body material in abutment therewith.
Claim 8
Dependent Claim
46 words
The torque disconnect means defined in claim 6 wherein said first means include: means for sliding engagement with the torque supplying means, said means for sliding engagement allowing said first means curvical gear teeth to move out of engagement with said second means curvical gear teeth.
Claim 9
Dependent Claim
43 words
The torque disconnect means defined in claim 7 wherein said abutment member defines passages therethrough, whereby said body material can flow through the passages of said abutment member to assure said body material allows said bias means to disconnect said curvical gear teeth.
Claim 10
Dependent Claim
66 words
The torque disconnect means defined in claim 8 wherein said shaft includes: a nut threadably connected thereto; and a spring washer, whereby said abutment member is connected to said shaft to apply compressive load by means of said nut and said spring washer which is positioned therebetween, said spring washer assuring a predetermined compressive force is applied across said thermal fuse when said nut is tightened.
Claim 11
Dependent Claim
48 words
The torque disconnect means defined in claim 9 wherein said second means include: a bearing connected to said second means, said bearing supporting a portion of said shaft for rotation and one end of said spring thereby enabling relative rotation between said first and second means when disconnected.
References Cited (Backward Citations)
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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) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |