US4070895A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for manufacturing bottom valve seat
Assignee: Tokico Ltd
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Filing: 1976-09-10
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Granted: 1978-01-31
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Expires: 1996-09-10
Abstract
Abstract A method for manufacturing a bottom valve seat for use in a hydraulic damper is provided including the steps of: punching out a circular blank from a flat plate of a given thickness to prepare a circular blank having given dimensions; drawing the blank into a cup-shaped work having a circumferential flange portion; forming a cylindrical wall in the cup-shaped work thus provided, with the wall having a given length; and pressing the central portion of a bottom portion of the cup-shaped work downwards or internally, thereby forming an annular flat portion along the circumferential edge of the bottom portion; cutting the flange portion into given dimensions; and punching a through hole in the flange portion. In this bottom valve seat, the flange portion has a flat surface and at least one oil passage is provided in the portion of the valve seat, which is opposite to the bottom portion.
Inventors
- 👤 Masami Yamada
- 👤 Yuji Soeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:31
CPC Classifications
B; B21; B21D; B21D53/00; B21D53/10; F; F16; F16F; F16F9/00; F16F9/32; F16F9/34; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49298; Y10T29/49306
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
178 words
A method for manufacturing a bottom valve seat for use in a hydraulic damper, in which projections defining fluid passages are provided on a lower end cover thereof, comprising the steps of: punching out a circular blank from a flat plate of a given thickness into a circular blank having given dimensions; drawing said blank into a cup-shape having a circumferential flange portion; forming a cylindrical wall for the cup-shaped work thus provided, said wall having a given length; pressing the central portion of the bottom portion of said cup-shaped work downwards or internally, thereby forming an annular flat portion along the circumferential edge of said bottom portion; cutting said flange portion to desired dimensions; and after said forming and pressing steps, punching a through-hole in the bottom portion of said cup-shaped work; said flange portion being thereby formed to have a flat surface on the side opposite the bottom portion thereof, and said annular flat portion of said bottom portion being thereby formed to have a curvature along its inner circumferential edge for supporting a double-sheet valve.
Claim 2
Independent Claim
178 words
A method for manufacturing a bottom valve seat for use in a hydraulic damper, in which projections defining fluid passages are provided on a lower end cover thereof, comprising the steps of: punching out a circular blank from a flat plate of a given thickness into a circular blank having given dimensions; drawing said blank into a cup-shape having a circumferential flange portion; forming a cylindrical wall for the cup-shaped work thus provided, said wall having a given length; pressing the central portion of the bottom portion of said cup-shaped work downwards or internally, thereby forming an annular flat portion along the circumferential edge of said bottom portion; cutting said flange portion to desired dimensions; and after said forming and pressing steps, punching a through-hole in the bottom portion of said cup-shaped work; said flange portion being thereby formed to have a flat surface on the side opposite the bottom portion thereof, and said annular flat portion of said bottom portion being thereby formed to have a curvature along its inner circumferential edge for supporting a double-sheet valve.
Claim 3
Dependent Claim
45 words
A method for manufacturing a bottom valve seat including the steps as set forth in claim 1, wherein the step of punching a through-hole in the bottom portion of said cup-shaped work is done after the step of cutting said flange portion to desired dimensions.
Claim 4
Dependent Claim
45 words
A method for manufacturing a bottom valve seat including the steps as set forth in claim 1, wherein the step of punching a through-hole in the bottom portion of said cup-shaped work is done before the step of cutting said flange portion to desired dimensions.
Claim 5
Independent Claim
183 words
A method for manufacturing a bottom valve seat for use in a hydraulic damper, in which projections defining fluid passages are not provided on a lower end cover thereof, comprising the steps of: punching out a circular blank from a flat plate having a given thickness; drawing said blank into a cup shape having a circumferential flange portion; forming a cylindrical wall portion of a given length for said cup-shaped work, said wall portion having a given length; pressing the bottom portion of said cup-shaped work internally to thereby form an annular flat portion along the circumferential edge of said bottom portion; cutting at least part of said flange portion; bending said flange portion to provide a leg portion; after said forming and pressing steps, punching a through-hole in the bottom portion of said cup-shaped work; said valve seat being thereby formed to provide at least one fluid passage on the side opposite to the bottom portion of said cup-shaped work, and said annular flat portion being thereby formed to have a curvature along its inner circumferential edge for supporting a double-sheet valve.
Claim 6
Independent Claim
183 words
A method for manufacturing a bottom valve seat for use in a hydraulic damper, in which projections defining fluid passages are not provided on a lower end cover thereof, comprising the steps of: punching out a circular blank from a flat plate having a given thickness; drawing said blank into a cup shape having a circumferential flange portion; forming a cylindrical wall portion of a given length for said cup-shaped work, said wall portion having a given length; pressing the bottom portion of said cup-shaped work internally to thereby form an annular flat portion along the circumferential edge of said bottom portion; cutting at least part of said flange portion; bending said flange portion to provide a leg portion; after said forming and pressing steps, punching a through-hole in the bottom portion of said cup-shaped work; said valve seat being thereby formed to provide at least one fluid passage on the side opposite to the bottom portion of said cup-shaped work, and said annular flat portion being thereby formed to have a curvature along its inner circumferential edge for supporting a double-sheet valve.
Claim 7
Dependent Claim
41 words
A method for manufacturing a bottom valve seat including the steps as set forth in claim 4, wherein the step of punching a through-hole in the bottom portion of said cup-shaped work is done in the last step of this method.
Claim 8
Dependent Claim
53 words
A method for manufacturing a bottom valve seat including the steps as set forth in claim 4, wherein the step of punching a through-hole in the bottom portion of said cup-shaped work is done immediately after the step of pressing the bottom portion to form the annular flat portion of said bottom portion.
Claim 9
Dependent Claim
46 words
A method for manufacturing a bottom valve seat including the steps as set forth in claim 4, wherein the step of punching a through-hole in the bottom portion of said cup-shaped work is done after the step of cutting at least part of said flange portion.
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) | 1981-01-30 | 1981-08-01 | 1982-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-30 | 1985-08-01 | 1986-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-30 | 1989-08-01 | 1990-01-31 | $7700.00 | Window Closed / Lapsed |