US3899256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanical pencil
Assignee: Individual
•
Filing: 1974-04-10
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Granted: 1975-08-12
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Expires: 1994-04-10
Abstract
Abstract A mechanical pencil has at the forward tip portion thereof a movable cylinder made up of a lead-protecting tube and an outside tube covering the lead-protecting tube. Lead extends through the lead-protecting tube and further through a chuck provided above the movable cylinder. A ring is provided for applying a load to the movable cylinder to add to its plunging movement for withdrawing into the pencil proper, the pencil proper having the forward tip directed upward at this time. The ring is the outside of the lead-protecting tube leaving a clearance between the ring and the lead-protecting tube. The outside tube is expanded at the bottom thereof so as to retain the ring therewith at the time of withdrawing the lead into the pencil proper.
Inventors
- 👤 Yoshihide Mitsuya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:52
CPC Classifications
B; B43; B43K; B43K24/00; B43K24/10; B43K24/18; B43K21/00; B43K21/02; B43K21/027; B43K21/16; B43K21/22
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
271 words
In a mechanical lead pencil having a forward tip with a cavity therein for containing a movable cylinder portion comprised of a lead-protecting tube extending through and beyond said tip and an outside tube covering within said cavity for surrounding a portion of the end of said lead-protecting tube within said cavity, and a push button controlled chuck located above said movable cylinder when said forward tip is pointed downward for holding and controlling the movement of lead in said pencil through said lead-protecting tube in response to depressing the push button, the improvement comprising: a ring located around said lead-protecting tube immediately below said outside tube covering within said cavity when the forward tip is pointed downward, said ring having an inside radius sufficiently large that the difference between the inside radius of said ring and the radius of said leadprotecting tube is greater than the difference between the outside radius of the ring and the radius of the cavity in which said ring is located, thereby preventing said ring from contacting said lead-protecting tube at any point; and an enlarged portion at the bottom of said outside tube covering immediately above said ring when said forward tip is pointed downward for preventing said ring from sliding over said outside tube covering when said forward tip is pointed upward, whereby pointing the forward tip upward and releasing said chuck surrounding the lead causes the lead and the leadprotecting tube to fall into the tip of the pencil under their own weight and under the force of the weight of the ring exerted against the enlarged portion of the outside tube.
Claim 2
Dependent Claim
271 words
In a mechanical lead pencil having a forward tip with a cavity therein for containing a movable cylinder portion comprised of a lead-protecting tube extending through and beyond said tip and an outside tube covering within said cavity for surrounding a portion of the end of said lead-protecting tube within said cavity, and a push button controlled chuck located above said movable cylinder when said forward tip is pointed downward for holding and controlling the movement of lead in said pencil through said lead-protecting tube in response to depressing the push button, the improvement comprising: a ring located around said lead-protecting tube immediately below said outside tube covering within said cavity when the forward tip is pointed downward, said ring having an inside radius sufficiently large that the difference between the inside radius of said ring and the radius of said leadprotecting tube is greater than the difference between the outside radius of the ring and the radius of the cavity in which said ring is located, thereby preventing said ring from contacting said lead-protecting tube at any point; and an enlarged portion at the bottom of said outside tube covering immediately above said ring when said forward tip is pointed downward for preventing said ring from sliding over said outside tube covering when said forward tip is pointed upward, whereby pointing the forward tip upward and releasing said chuck surrounding the lead causes the lead and the leadprotecting tube to fall into the tip of the pencil under their own weight and under the force of the weight of the ring exerted against the enlarged portion of the outside tube.
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) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |