Patent US3925842A successfully refreshed from Google Patents.
US3925842A
Expired / Lapsed
US
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Power eraser
Assignee: Semo Inc
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Filing: 1975-02-21
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Granted: 1975-12-16
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Expires: 1995-02-21
Abstract
Abstract An electrical eraser having a linearly reciprocating drive for oscillating an elongated erasing element along its longitudinal axis. This motion of the element provides fast erasing action with minimum abrasion or fraying of paper.
Inventors
- 👤 Bjorn P Selinder
- 👤 Bo Eric Selinder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:43
CPC Classifications
H; H02; H02K; H02K33/00; H02K33/02; B; B43; B43L; B43L19/00; B43L19/0006
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
89 words
A power eraser comprising: a housing; a chuck means adapted to hold an elongated rod-shaped eraser element; an elongated eraser element secured in and extending from the chuck means, the eraser element being of a type specifically adapted for removing marks from paper and the like; and linearly reciprocating drive means secured to the housing and to the chuck means for oscillating the chuck means and eraser element along the longitudinal axis of the eraser element, the chuck means being substantially free of movement lateral to the eraser-element axis.
Claim 2
Dependent Claim
89 words
A power eraser comprising: a housing; a chuck means adapted to hold an elongated rod-shaped eraser element; an elongated eraser element secured in and extending from the chuck means, the eraser element being of a type specifically adapted for removing marks from paper and the like; and linearly reciprocating drive means secured to the housing and to the chuck means for oscillating the chuck means and eraser element along the longitudinal axis of the eraser element, the chuck means being substantially free of movement lateral to the eraser-element axis.
Claim 3
Dependent Claim
57 words
The power eraser defined in claim 1 wherein the drive means includes a hollow coil supported in the housing, connection means coupled to the coil for electrically energizing the coil, and a magnetic core positioned within the coil to be driven by and movable with respect to the coil, the core being secured to the chuck means.
Claim 4
Dependent Claim
20 words
The power eraser defined in claim 2 wherein the connection means includes a rectifier connected in series with the coil.
Claim 5
Dependent Claim
29 words
The power eraser defined in claim 2 wherein the drive means further includes a pair of springs bearing on opposite ends of the core and supported within the housing.
Claim 6
Dependent Claim
32 words
The power eraser defined in claim 4 wherein the springs are coil springs of unequal spring rate, the spring of lower spring rate being positioned between the chuck means and magnetic core.
Claim 7
Dependent Claim
76 words
The power eraser defined in claim 2 and further comprising a hollow bobbin supporting the coil and surrounding the core, a pair of split ferrous rings secured in opposite ends of the bobbin, a pair of split ferrous disks secured to the rings and extending over end faces of the bobbin, and a split ferrous sleeve extending between the split disks around the coil, the rings, disks and sleeve having split portions which are radially aligned.
Claim 8
Dependent Claim
78 words
The power eraser defined in claim 2 wherein the housing comprises a hollow casing extending around the coil, and an end cap secured to the casing, the casing and end cap each supporting a respective bearing, and further comprising a pair of non-ferrous tubes secured to opposite ends of the core and extending through and supported for linear reciprocating movement by the respective bearings, the chuck means being disposed at the outer end of one of the tubes.
Claim 9
Dependent Claim
72 words
The power eraser defined in claim 7 and further comprising a field-concentrating ferrous shell extending around outer surfaces of the coil, a diode, and a switch in series connection with the diode and coil, and wherein the drive means further includes a pair of springs of unequal spring rate positioned within the housing at opposite ends of the core for resiliently supporting the core for longitudinal movement with respect to the coil.
Claim 10
Dependent Claim
32 words
The power eraser defined in claim 2 wherein the core and chuck means are coaxially aligned hollow tubes whereby the elongated eraser element can extend through the chuck means into the core.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-15 | 1979-06-16 | 1979-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-15 | 1983-06-16 | 1983-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-15 | 1987-06-16 | 1987-12-16 | $7700.00 | Window Closed / Lapsed |