Patent US3790291A successfully refreshed from Google Patents.
US3790291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Useful writing instrument
Assignee: Individual
•
Filing: 1972-07-17
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Granted: 1974-02-05
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Expires: 1992-07-17
Abstract
Abstract A writing instrument comprises a tubular casing with a writing unit which is frictionally interfitted with the front end of the casing, and an ejector means for ejecting the writing unit from the casing as its writing point becomes blunt for replacement by a sharpened unit. Each writing unit carries a sharpened lead pencil element or the like at its front portion and includes a suddenly enlarging and gradually reducing portion at its middle portion, while its rear portion has substantially the same shape as the front section. The ejector means further comprises a tubular casing in which the remaining writing units of a plurality of writing units are stored, with an ejector at its closed end and a plurality of annular flexible projections at its opened end to prevent the stored writing units therein from slipping out from behind the ejector tube.
Inventors
- 👤 Y Liu
- 👤 Y Hung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:44
CPC Classifications
B; B43; B43K; B43K21/00; B43K21/003
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
202 words
A writing instrument comprising: a tubular casing member adapted at the front end thereof for securely receiving a writing unit therein; a writing unit operatively projecting a writing portion thereof from said casing member, said writing unit comprising said writing portion and a writing body, said writing body including a front portion for securing said writing portion, a middle portion for providing a secure interfitting engagement with the front end of said casing member, and a rear portion capable of being grasped and extracted from a storage means, wherein the middle portion of said writing Unit and the front end of the casing member are structurally interfitted to prevent vibration upon the application of pressure to said writing unit during use, and wherein the interior of the casing member at the front end thereof defines an inwardly directed, rearwardly contracting, conical taper for receiving a corresponding conical taper on the expanded middle portion of said writing unit in an interfitting relationship; and means for ejecting said writing member, said ejecting means further defining means for storing a plurality of said writing members therein in a manner which is operatively isolated from said writing member projecting a writing portion from said casing member.
Claim 2
Dependent Claim
202 words
A writing instrument comprising: a tubular casing member adapted at the front end thereof for securely receiving a writing unit therein; a writing unit operatively projecting a writing portion thereof from said casing member, said writing unit comprising said writing portion and a writing body, said writing body including a front portion for securing said writing portion, a middle portion for providing a secure interfitting engagement with the front end of said casing member, and a rear portion capable of being grasped and extracted from a storage means, wherein the middle portion of said writing Unit and the front end of the casing member are structurally interfitted to prevent vibration upon the application of pressure to said writing unit during use, and wherein the interior of the casing member at the front end thereof defines an inwardly directed, rearwardly contracting, conical taper for receiving a corresponding conical taper on the expanded middle portion of said writing unit in an interfitting relationship; and means for ejecting said writing member, said ejecting means further defining means for storing a plurality of said writing members therein in a manner which is operatively isolated from said writing member projecting a writing portion from said casing member.
Claim 3
Dependent Claim
53 words
The writing instrument as set forth in claim 1 wherein the interior of said tubular casing member adjacent said inwardly directed, rearwardly contracting conical taper defines a cylindrical section for receiving and securing the rear portion of said writing unit when said writing unit is positioned in the front end of said casing.
Claim 4
Dependent Claim
55 words
The writing instrument as set forth in claim 1 wherein said ejecting and storage means is a tubular member slideably engaged within said tubular casing, said tubular member defining a closed end for engaging the rear portion of said writing unit when said tubular member is depressed to expel said writing unit from said casing.
Claim 5
Dependent Claim
43 words
The writing instrument as set forth in claim 3 wherein the closed end of said tubular member is sized to pass through said cylindrical section of said casing member for a predetermined length to eject a used writing unit from said casing member.
Claim 6
Dependent Claim
30 words
The writing instrument as set forth in claim 3 wherein said tubular member further includes an enlarged portion for slideably and frictionally engaging the interior of said tubular casing member.
Claim 7
Dependent Claim
35 words
The writing instrument as set forth in claim 5 wherein the tubular member is free from frictional engagement with the interior of said tubular casing member except at said enlarged portion of said tubular member.
Claim 8
Dependent Claim
63 words
The writing instrument as set forth in claim 3 wherein said tubular member includes a second enlarged portion at an open end thereof opposite said closed end, said second enlarged portion including a plurality of flexible, radially inwardly extending projections for retaining said writing units within said tubular member and being capable of permitting withdrawal of said writing units from said tubular member.
Claim 9
Dependent Claim
51 words
The writing instrument as set forth in claim 5 wherein said flexible projections extend inwardly to an extent to define a free space capable of permitting the rear portion of said writing member to extend therefrom to be grasped for removal from said tubular member when said writing instrument is inverted.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |