US4224727A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making the body of a hydraulic master cylinder
Assignee: Astemo Ltd
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Filing: 1978-05-25
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Granted: 1980-09-30
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Expires: 1998-05-25
Abstract
Abstract A master cylinder body including a cylindrical-shaped inner section of uniform wall thickness formed as by die-casting and an outer section cast on the inner section around the periphery thereof. The extreme simplicity in configuration of the inner section enables it to be formed with no casting defects such as shrinkage cavities which may result in oil leakage therethrough. The inner section and the outer one cast thereon become solidly fused together at the cylindrical interface therebetween as long as the materials used are of the same metallurgical type. Formation of a multitude of annular or helical ridges on the outer periphery of the inner body section further ensures the solid interconnection between the two body sections.
Inventors
- 👤 Yukikazu Miyashita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:09
CPC Classifications
B; B23; B23P; B23P15/00; B23P15/001; B60; B60T; B60T11/00; B60T11/10; B60T11/16; B60T11/165; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/4927; Y10T29/49272; Y10T29/4998; Y10T29/49988
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
119 words
A method of making the body of a hydraulic master cylinder comprising the steps of: forming a cylindrically shaped inner body section of substantially uniform wall thickness at all parts thereof, having a cylinder bore therein; casting an outer body section on said inner body section around the outer periphery thereof said outer body section having an oil reservoir intergrally formed therein, from a material substantially the same as that of said inner body section, whereby, said inner and outer body sections fuse to one another at the cylindrical interface therebetween and forming port means through said outer and inner body sections for communication between the interior of said reservoir and the cylinder bore of said inner body section.
Claim 2
Independent Claim
119 words
A method of making the body of a hydraulic master cylinder comprising the steps of: forming a cylindrically shaped inner body section of substantially uniform wall thickness at all parts thereof, having a cylinder bore therein; casting an outer body section on said inner body section around the outer periphery thereof said outer body section having an oil reservoir intergrally formed therein, from a material substantially the same as that of said inner body section, whereby, said inner and outer body sections fuse to one another at the cylindrical interface therebetween and forming port means through said outer and inner body sections for communication between the interior of said reservoir and the cylinder bore of said inner body section.
Claim 3
Dependent Claim
41 words
A method as set forth in claim 1, further comprising the steps of: forming a multitude of integral ridges on said inner body section around the outer periphery thereof, before said outer body section is cast on said inner body section.
Claim 4
Dependent Claim
20 words
A method as set forth in claim 2, wherein: said ridges are annular, extending circumferentially around said inner body section.
Claim 5
Dependent Claim
19 words
A method as set forth in claim 2, wherein: said ridges are in the form of double helical knurls.
References Cited (Backward Citations)
US731748A
Cited
US1682590A
Cited
US2903763A
Cited
US3073290A
Cited
US3276082A
Cited
US4122596A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-30 | 1984-03-31 | 1984-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-30 | 1988-03-31 | 1988-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-30 | 1992-03-31 | 1992-09-30 | $7700.00 | Window Closed / Lapsed |