US4145068A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing bicycle frame by die casting and bicycle frame manufactured thereby
Assignee: Bridgestone Cycle Co Ltd
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Filing: 1977-06-08
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Granted: 1979-03-20
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Expires: 1997-06-08
Abstract
Abstract A bicycle frame comprises tubes closed at their ends and lugs for connecting the tubes to form the frame, which lugs are formed by die casting in dies in which the tubes are arranged so as to integrally surround the closed ends of the tubes by the die-cast lugs. The tubes are previously formed at their ends with tapered portions each extending from that corresponding to an extreme end of a boss of the lug surrounding the end of the tube toward an extreme end of the tube. The outer surfaces of the bosses of the die-cast lugs are in substantially constant outer diameter or slightly tapered, thereby, in conjunction with the tapered portions of the tube, eliminating stress concentrations at the extreme ends of the bosses of the lugs, and saving the amount of the die-cast metal resulting in light weight bicycles which can save driving power and cost of manufacture.
Inventors
- 👤 Takeshi Toyomasu
- 👤 Michito Furusawa
- 👤 Sadao Mabuchi
- 👤 Mitsuo Gushima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:51
CPC Classifications
B; B62; B62K; B62K19/00; B62K19/18; B22; B22D; B22D19/00; B22D19/04; B22D19/045; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4998; Y10T29/49988
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
197 words
A method of manufacturing a bicycle frame consisting of tubes previously closed at their ends and die-cast lugs for connecting said tubes, including steps of arranging said tubes in position in a final frame in dies and forcing molten metal into cavities of said dies corresponding in configuration to said lugs to form said lugs by said molten metal integrally including said closed ends of said tubes, the improvement comprising steps of forming tapered portions at said closed ends of the tubes before die casting said lugs, said tapered portion extending from that corresponding to an extreme end of a boss of said lug surrounding the end of the tube toward an extreme end of the tube, closing each said end of said tube by a closure member oblique to a longitudinal axis of the tube and in parallel with an outer surface of a tube to be buttingly connected to said tube, and forming outer surfaces of said bosses of the die-cast lugs in substantially constant outer diameter, thereby progressively reducing thicknesses of walls of the bosses at their extreme ends along said tapered portions of said tubes, maintaining necessary and sufficient thickness of said lugs.
Claim 2
Independent Claim
197 words
A method of manufacturing a bicycle frame consisting of tubes previously closed at their ends and die-cast lugs for connecting said tubes, including steps of arranging said tubes in position in a final frame in dies and forcing molten metal into cavities of said dies corresponding in configuration to said lugs to form said lugs by said molten metal integrally including said closed ends of said tubes, the improvement comprising steps of forming tapered portions at said closed ends of the tubes before die casting said lugs, said tapered portion extending from that corresponding to an extreme end of a boss of said lug surrounding the end of the tube toward an extreme end of the tube, closing each said end of said tube by a closure member oblique to a longitudinal axis of the tube and in parallel with an outer surface of a tube to be buttingly connected to said tube, and forming outer surfaces of said bosses of the die-cast lugs in substantially constant outer diameter, thereby progressively reducing thicknesses of walls of the bosses at their extreme ends along said tapered portions of said tubes, maintaining necessary and sufficient thickness of said lugs.
Claim 3
Dependent Claim
155 words
A bicycle frame consisting of tubes closed at their ends and lugs for connecting said tubes said lugs being formed by die casting integrally with said closed ends of said tubes, the improvement comprising said tubes being formed at their closed ends with tapered portions each extending from that corresponding to an extreme end of a boss of said lug surrounding the end of the tube toward an extreme end of the tube, each said closed end of said tube being closed by a closure member oblique to a longitudinal axis of the tube and in parallel with an outer surface of a tube to be buttingly connected to said tube, and outer surfaces of said bosses of the die-cast lugs being in substantially constant outer diameter, thereby progressively reducing thicknesses of walls of the bosses at their extreme ends along said tapered portions of said tubes, maintaining necessary and sufficient thickness of said lugs.
Claim 4
Dependent Claim
155 words
A bicycle frame consisting of tubes closed at their ends and lugs for connecting said tubes said lugs being formed by die casting integrally with said closed ends of said tubes, the improvement comprising said tubes being formed at their closed ends with tapered portions each extending from that corresponding to an extreme end of a boss of said lug surrounding the end of the tube toward an extreme end of the tube, each said closed end of said tube being closed by a closure member oblique to a longitudinal axis of the tube and in parallel with an outer surface of a tube to be buttingly connected to said tube, and outer surfaces of said bosses of the die-cast lugs being in substantially constant outer diameter, thereby progressively reducing thicknesses of walls of the bosses at their extreme ends along said tapered portions of said tubes, maintaining necessary and sufficient thickness of said lugs.
References Cited (Backward Citations)
US3456330A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-19 | 1982-09-18 | 1983-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-19 | 1986-09-18 | 1987-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-19 | 1990-09-18 | 1991-03-20 | $7700.00 | Window Closed / Lapsed |