US4218148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Matrix printing cell and head assembly
Assignee: PRINTER ASSOC
•
Filing: 1977-11-18
•
Granted: 1980-08-19
•
Expires: 1997-11-18
Abstract
Abstract An improved printing cell and head for dot matrix impact printers, including an armature of exceptionally low mass mounted on a pair of straight, cylindrical spring elements, and driven by a pair of coils wired in parallel. By careful selection of the ramp angle of respective pole faces, and a resilient preset and energy-absorbing device, printing speeds of 2,500 Hz can be achieved with remarkably quiet operation.
Inventors
- 👤 Arthur L. Matschke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:06
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/22; B41J2/23; B41J2/27
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
251 words
An electromagnet assembly for a dot matrix print head comprising: a magnetizable armature; front and rear columnar wire springs secured near the ends of said armature and supporting same for movement from a rest position to a printing position and back without angular change during movement; a generally W-shaped magnetizable core member having a base; a pair of legs extending from said base toward said armature, the ends of said legs forming a first pair of pole faces; a third leg at the rear of said base and forming a tower; said front spring being secured in said base at the front end thereof, and said rear spring being secured between said tower and the nearest of said pair of legs; said first pair of pole faces being adjacent said armature and each forming an identical acute angle in the range of 16° to 20° with the axis thereof; a second pair of pole faces on said armature at the same angle to said axis as said first pair and defining therebetween a pair of air gaps tending to close when said armature moves from a rest position to a printing position; coil means on said pair of legs; slightly resilient preset means secured on said tower and including a vertical surface pressing against the rear end of said armature in the rest position; a vertical slot closely surrounding but not touching said rear spring in the rest position; and a print wire secured in the forward end of said armature.
Claim 2
Dependent Claim
251 words
An electromagnet assembly for a dot matrix print head comprising: a magnetizable armature; front and rear columnar wire springs secured near the ends of said armature and supporting same for movement from a rest position to a printing position and back without angular change during movement; a generally W-shaped magnetizable core member having a base; a pair of legs extending from said base toward said armature, the ends of said legs forming a first pair of pole faces; a third leg at the rear of said base and forming a tower; said front spring being secured in said base at the front end thereof, and said rear spring being secured between said tower and the nearest of said pair of legs; said first pair of pole faces being adjacent said armature and each forming an identical acute angle in the range of 16° to 20° with the axis thereof; a second pair of pole faces on said armature at the same angle to said axis as said first pair and defining therebetween a pair of air gaps tending to close when said armature moves from a rest position to a printing position; coil means on said pair of legs; slightly resilient preset means secured on said tower and including a vertical surface pressing against the rear end of said armature in the rest position; a vertical slot closely surrounding but not touching said rear spring in the rest position; and a print wire secured in the forward end of said armature.
Claim 3
Dependent Claim
21 words
The electromagnet assembly as claimed in claim 1, wherein the forward edges of said first pair of pole faces are flattened.
Claim 4
Dependent Claim
22 words
The electromagnet assembly as claimed in claim 1, wherein said springs are secured in said armature and base by welding or sintering.
Claim 5
Dependent Claim
23 words
The electromagnet assembly as claimed in claim 1, and additionally comprising means in said base for securing said assembly in a print head.
Claim 6
Dependent Claim
28 words
The electromagnet assembly as claimed in claim 1, and additionally comprising set screw means in said tower, whereby said preset may be adjusted with respect to said armature.
Claim 7
Dependent Claim
32 words
The electromagnet assembly as claimed in claim 1, wherein said coil means are wound on bobbins having a slight resiliency, said bobbins fitting over said pair of legs with a clearance fit.
Claim 8
Dependent Claim
29 words
The electromagnet assembly as claimed in claim 1, wherein said preset means has a vertical cavity fitting loosely over said tower and is secured thereto with a resilient cement.
Claim 9
Dependent Claim
16 words
The electromagnet assembly as claimed in claim 1, wherein said coil means are connected in parallel.
Claim 10
Dependent Claim
147 words
An electromagnet assembly for a dot matrix print head comprising: a generally W-shaped, magnetizable core member including a base portion and three upwardly extending legs, the forward pair of legs terminating in a pair of rear-sloping pole faces, and the rear leg forming a tower; a pair of columnar wire springs secured in said base portion on either side of said pair of legs; a magnetizable armature secured over said pole faces on said springs and including a pair of forward-sloping pole faces forming an air gap with said rear-sloping pole faces, the slope angle of each pair being identical; coils on each of said pair of legs; slightly resilient preset means mounted on said tower and including a surface pressing against the rear end of said armature and a slot surrounding the adjacent spring; and a print wire secured in the front end of said armature.
Claim 11
Dependent Claim
147 words
An electromagnet assembly for a dot matrix print head comprising: a generally W-shaped, magnetizable core member including a base portion and three upwardly extending legs, the forward pair of legs terminating in a pair of rear-sloping pole faces, and the rear leg forming a tower; a pair of columnar wire springs secured in said base portion on either side of said pair of legs; a magnetizable armature secured over said pole faces on said springs and including a pair of forward-sloping pole faces forming an air gap with said rear-sloping pole faces, the slope angle of each pair being identical; coils on each of said pair of legs; slightly resilient preset means mounted on said tower and including a surface pressing against the rear end of said armature and a slot surrounding the adjacent spring; and a print wire secured in the front end of said armature.
Claim 12
Dependent Claim
22 words
The electromagnet assembly as claimed in claim 9, wherein said slope angle is 16° to 20° to the axis of said armature.
Claim 13
Dependent Claim
19 words
The electromagnet assembly as claimed in claim 9, wherein the forward edges of said rear-sloping pole faces are flattened.
Claim 14
Dependent Claim
23 words
The electromagnet assembly as claimed in claim 9, wherein said springs are secured in said armature and base portion by welding or sintering.
Claim 15
Dependent Claim
23 words
The electromagnet assembly as claimed in claim 9, and additionally comprising means in said base for securing said assembly in a print head.
Claim 16
Dependent Claim
29 words
The electromagnet assembly as claimed in claim 9, and additionally comprising set screw means in said tower, whereby said preset means may be adjusted with respect to said armature.
Claim 17
Dependent Claim
31 words
The electromagnet assembly as claimed in claim 9, wherein said coils are wound on bobbins having a slight resiliency, said bobbins fitting over said pair of legs with a clearance fit.
Claim 18
Dependent Claim
29 words
The electromagnet assembly as claimed in claim 9, wherein said preset means has a vertical cavity fitting loosely over said tower and is secured thereto with a resilient cement.
Claim 19
Dependent Claim
15 words
The electromagnet assembly as claimed in claim 9, wherein said coils are connected in parallel.
Claim 20
Dependent Claim
153 words
In an electromagnet assembly for driving a print wire in a dot matrix print head, the improvements comprising: magnetizable armature means secured to said print wire and driving said print wire upon energization of said electromagnet assembly; two pole faces on said armature means at an angle of 16° to 20° to the axis thereof; magnetizable core means including a pair of coils and a pair of core pole faces sloped similarly to said armature pole faces and defining therebetween two closeable air gaps; columnar spring means securing said armature means to said core means near the ends of said armature means; and slightly resilient preset means secured to said core means and adapted to engage the rear end of said armature means in the rest position and including a slot surrounding but not touching the adjacent one of said spring means in all but the operational direction, when in the rest position.
Claim 21
Dependent Claim
153 words
In an electromagnet assembly for driving a print wire in a dot matrix print head, the improvements comprising: magnetizable armature means secured to said print wire and driving said print wire upon energization of said electromagnet assembly; two pole faces on said armature means at an angle of 16° to 20° to the axis thereof; magnetizable core means including a pair of coils and a pair of core pole faces sloped similarly to said armature pole faces and defining therebetween two closeable air gaps; columnar spring means securing said armature means to said core means near the ends of said armature means; and slightly resilient preset means secured to said core means and adapted to engage the rear end of said armature means in the rest position and including a slot surrounding but not touching the adjacent one of said spring means in all but the operational direction, when in the rest position.
Claim 22
Dependent Claim
29 words
The electromagnet assembly as claimed in claim 18, and additionally comprising adjustment means adapted to press said preset means against said armature means and thereby tension said spring means.
Claim 23
Dependent Claim
36 words
The electromagnet assembly as claimed in claim 19, and additionally comprising tower means integral with said core means and supporting said preset means, said preset means being secured to said tower means with a resilient cement.
Claim 24
Dependent Claim
20 words
The electromagnet assembly as claimed in claim 20, wherein said adjustment means comprises a set screw in said tower means.
Claim 25
Dependent Claim
17 words
The electromagnet assembly as claimed in claim 21, wherein said set screw includes a slightly resilient tip.
References Cited (Backward Citations)
US3187668A
Cited
US3335659A
Cited
US3467232A
Cited
US3842955A
Cited
US3842737A
Cited
US3994381A
Cited
US3897865A
Cited
US3893220A
Cited
US4004671A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-19 | 1984-02-18 | 1984-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-19 | 1988-02-18 | 1988-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-19 | 1992-02-18 | 1992-08-19 | $7700.00 | Window Closed / Lapsed |