Patent US4486183A successfully refreshed from Google Patents.
Patent US3914969A successfully refreshed from Google Patents.
US3914969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for forming dished ion thruster grids
Assignee: National Aeronautics and Space Administration
•
Filing: 1974-04-22
•
Granted: 1975-10-28
•
Expires: 1994-04-22
Abstract
Abstract An impervious metal sheet is placed on top of a pair of flat grid blanks which are clamped together at their edges. An elastic sheet contacts the bottom grid blank, and a second impervious metal sheet is inserted between the two grid blanks if the grids have high percentage open areas. All of the blanks and sheets are dished simultaneously by forcing fluid to inflate the elastic sheet. The dished grids are also stress relieved simultaneously.
Inventors
- 👤 Bruce A Banks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:50
CPC Classifications
F; F03; F03H; F03H1/00; F03H1/0037; F03H1/0043; B; B21; B21D; B21D26/00; B21D26/02; B21D26/021; B21D26/025; B21D26/053; B21D26/059; H; H01; H01J; H01J19/00; H01J2893/00; H01J2893/0001; H01J2893/0012; H01J2893/0019; H01J2893/0022
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
232 words
Apparatus for forming matched pairs of dished grids having high open areas to substantially hemispheroidal configurations for ion thruster accelerator systems from substantially flat grid blanks comprising a base member for supporting a pair of said grid blanks to substantial alignment, a first substantially flat sheet of impervious metal engaging a surface of one of said grid blanks remote from said base member, a sheet of elastic material covering a surface of said base member, said sheet of elastic material contacting the other of said grid blanks not engaging said impervious metal sheet, a second substantially flat sheet of impervious metal interposed between said grid blanks to prevent portions of one of said pair of grids from being forced into the openings of the other of said pair of grids, a ring contacting said first substantially flat sheet, means for securing said ring to said base member thereby clamping the marginal peripheral portions of said assembled grid blanks and impervious sheets to hold said assembled blanks and sheets in contact with each other to prevent slippage thereof and forming an expansible fluid chamber within said ring between said elastic material and said base member, and means for applying fluid pressure between said elastic material and said base member thereby inflating said elastic material into said ring whereby said assembled blanks and sheets are dished to the curvature of said inflated elastic material.
Claim 2
Dependent Claim
232 words
Apparatus for forming matched pairs of dished grids having high open areas to substantially hemispheroidal configurations for ion thruster accelerator systems from substantially flat grid blanks comprising a base member for supporting a pair of said grid blanks to substantial alignment, a first substantially flat sheet of impervious metal engaging a surface of one of said grid blanks remote from said base member, a sheet of elastic material covering a surface of said base member, said sheet of elastic material contacting the other of said grid blanks not engaging said impervious metal sheet, a second substantially flat sheet of impervious metal interposed between said grid blanks to prevent portions of one of said pair of grids from being forced into the openings of the other of said pair of grids, a ring contacting said first substantially flat sheet, means for securing said ring to said base member thereby clamping the marginal peripheral portions of said assembled grid blanks and impervious sheets to hold said assembled blanks and sheets in contact with each other to prevent slippage thereof and forming an expansible fluid chamber within said ring between said elastic material and said base member, and means for applying fluid pressure between said elastic material and said base member thereby inflating said elastic material into said ring whereby said assembled blanks and sheets are dished to the curvature of said inflated elastic material.
Claim 3
Dependent Claim
61 words
Apparatus for forming matched pairs of dished grids as claimed in claim 1 wherein the base member has at least one passage therethrough terminating at an aperture in the surface of said base member covered by the elastic material, and a supply of hydraulic fluid under pressure selectively connected to said passage for introducing fluid under pressure to said elastic sheet.
Claim 4
Dependent Claim
61 words
Apparatus for forming matched pairs of dished grids as claimed in claim 1 wherein the ring has a protuberance thereon for engaging said first impervious metal sheet and deforming a portion of the assembled grid blanks into a mating depression in said base member thereby clamping the peripheral edges of the grids and metal sheets to prevent random slippage during dishing.
Claim 5
Dependent Claim
35 words
Apparatus for forming matched pairs of dished grids as claimed in claim 3 wherein the base member has a passage therein for placing the expansible chamber in communication with a source of high pressure fluid.
Claim 6
Dependent Claim
19 words
Apparatus for forming matched pairs of dished grids as claimed in claim 4 wherein the source contains hydraulic liquid.
Claim 7
Dependent Claim
30 words
Apparatus for forming matched pairs of dished grids as claimed in claim 5 including an intermediate female die in the ring for dIstributing the elongation of the grids during dishing.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |