EP0078551A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Blank tube and main frame for a by bicycle
Assignee: Bridgestone Cycle Co Ltd
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Filing: 1982-11-04
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Granted: —
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Expires: 2002-11-04
Abstract
Abstract A blank tube constituting a main frame for a two-wheeled vehicle, comprises a main tubular portion having thicker walls in the proximity of its ends subjected to the largest forces and tubular expanded portions extending from the ends of the tube for receiving a head tube and a seat tube without using separate parts such as lugs. The blank tube further comprises a gradually enlarged diameter portion adjacent to the tubular expanded portions to more improve the strength of the tube. The thicker walls, tubular expanded portions and gradually enlarged diameter portion are formed simultaneously in dies by bulging Moreover, the dies are formed with recesses, so that the blank tube is formed with protrusions. The protrusions are formed with apertures for passing brake wires or electric wires through the tube. The main tubular portion of the blank tube is formed in a particular cross-section effectively increasing its strength by pressing by means of the dies including corresponding sectional cavities.
Inventors
- 👤 Kikuzo Takamiya
- 👤 Hiroshi Todoroki
- 👤 Shuichi Taniguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 08:21
CPC Classifications
B; B21; B21D; B21D26/00; B21D26/02; B21D26/033; B21D26/037; B21D35/00; B21D35/002; B21D35/005; B21D35/006; B21D53/00; B21D53/86; B62; B62K; B62K19/00; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49805
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
72 words
A blank tube for a two-wheeled vehicle, comprising a main tubular portion having thicker walls at required portions and tubular expanded portions extending from at least one end of the thicker wall of said main tubular portion, said thicker walls and said tubular expanded portions being formed in dies by applying high hydraulic pressure to an inside of said tube and simultaneously applying compressive force to said tube in its axial direction.
Claim 2
Dependent Claim
72 words
A blank tube for a two-wheeled vehicle, comprising a main tubular portion having thicker walls at required portions and tubular expanded portions extending from at least one end of the thicker wall of said main tubular portion, said thicker walls and said tubular expanded portions being formed in dies by applying high hydraulic pressure to an inside of said tube and simultaneously applying compressive force to said tube in its axial direction.
Claim 3
Dependent Claim
34 words
A blank tube as set forth in claim 1, wherein said main tubular portion comprises a gradually enlarged diameter portion adjacent to said tubular expanded portions at at least one end of the tube.
Claim 4
Dependent Claim
40 words
A blank tube as set forth in claim 1, wherein said main tubular portion comprises protrusions formed thereon simultaneously with the forming of said thicker walls and said tubular expanded portions with the aid of recesses formed in said dies.
Claim 5
Dependent Claim
38 words
A blank tube as set forth in claim 3, wherein said protrusions are hemiconical which is of a shape obtained by dividing a cone substantially along its generators passing through its apex and their bottom surfaces with apertures.
Claim 6
Dependent Claim
39 words
A blank tube as set forth in claim 1, wherein said main tubular portion has a particular cross-section formed by said dies having corresponding cross-sectional cavity simultaneously with the forming of said thicker walls and said tubular expanded portions.
Claim 7
Dependent Claim
43 words
A blank tube as set forth in claim 5, wherein said particular cross-section of the main tubular portion is one selected from substantially vertically elongated elliptical, substantially vertically elongated rectangular and substantially inverted triangular sections and substantially rectangular section including a concaved portion.
Claim 8
Dependent Claim
123 words
A main frame for a two-wheeled vehicle, comprising a blank tube including a main tubular portion having thicker walls at required portions and tubular expanded portions extending from at least one end of the thicker wall of said main tubular portion, said thicker walls and said tubular expanded portions being formed in dies by applying high hydraulic pressure to an inside of said tube and simultaneously applying compressive force to said tube in its axial direction, distal ends of said tubular expanded portions being cut off to form through-holes and at least one compressed end of said main tubular portion being cut off to form an opening; and a head tube and a seat tube inserted into and fixed to said through-holes, respectively.
Claim 9
Dependent Claim
123 words
A main frame for a two-wheeled vehicle, comprising a blank tube including a main tubular portion having thicker walls at required portions and tubular expanded portions extending from at least one end of the thicker wall of said main tubular portion, said thicker walls and said tubular expanded portions being formed in dies by applying high hydraulic pressure to an inside of said tube and simultaneously applying compressive force to said tube in its axial direction, distal ends of said tubular expanded portions being cut off to form through-holes and at least one compressed end of said main tubular portion being cut off to form an opening; and a head tube and a seat tube inserted into and fixed to said through-holes, respectively.
Claim 10
Dependent Claim
33 words
A main frame as set forth in claim 7, wherein said main frame comprises an inner tube press fitted in one of said through-holes before said head tube is inserted into the through-hole.
Claim 11
Dependent Claim
49 words
A main frame as set forth in claim 8, wherein said inner tube includes a top bearing cup and a bottom bearing cup press fitted in an upper and a lower end of said inner tube to form a top and a bottom bearing support for the head tube.
Claim 12
Dependent Claim
34 words
A main frame as set forth in claim 7, wherein said main tubular portion comprises a gradually enlarged diameter portion adjacent to said tubular expanded portions at at least one end of the tube.
Claim 13
Dependent Claim
40 words
A main frame as set forth in claim 7, wherein said main tubular portion comprises protrusions formed thereon simultaneously with the forming of said thicker walls and said tubular expanded portions with the aid of recesses formed in said dies.
Claim 14
Dependent Claim
38 words
A main frame as set forth in claim 11, wherein said protrusions are hemiconical which is of a shape obtained by dividing a cone substantially along its generators passing through its apex and their bottom surfaces with apertures.
Claim 15
Dependent Claim
39 words
A main frame as set forth in claim 7, wherein said main tubular portion has a particular cross-section formed by said dies having corresponding cross-sectional cavity simultaneously with the forming of said thicker walls and said tubular expanded portions.
Claim 16
Dependent Claim
43 words
A main frame as set forth in claim 13, wherein said particular cross-section of the main tubular portion is one selected from substantially vertically elongated elliptical, substantially vertically elongated rectangular and substantially inverted triangular sections and substantially rectangular section including a concaved portion.
References Cited (Backward Citations)
No citation records indexed.
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