US4034841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Print wire actuating device for a dot matrix printer
Assignee: NEC Corp
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Filing: 1975-10-21
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Granted: 1977-07-12
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Expires: 1995-10-21
Abstract
Abstract A print wire solenoid device including a disc type plunger-restoring spring which consists of a continuous annular peripheral portion and spoke portions extending radially inwardly therefrom jointly to define a central opening for fitting engagement with the plunger. The plunger and the stationary core or stem members defining a solenoid gap, therebetween are both conically formed to minimize leakage of magnetic flux, thereby substantially increasing the effective flux density and hence the force of attraction. The disc spring, which is neither fixedly secured at any point to the plunger nor to the other adjacent components, is free from any stress concentration in operation and thus not only enables high speed printing operation with an increased length of stroke but facilitates fabrication of the device in combination with the conical formation of the plunger and stem members, which facilitates reduction in size and weight of the devices as well as in power consumption.
Inventors
- 👤 Sigeru Ohyama
- 👤 Aisuke Sekikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:43
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/22; B41J2/23; B41J2/27; B41J2/285
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
165 words
In a print wire actuating device for a dot matrix type printer, of the type which includes a solenoid assembly comprising a plunger type solenoid armature having a print wire fixed to the front end thereof in aligned relation therewith and a disc-like spring member supporting said solenoid armature and normally biasing said solenoid armature rearwardly into abutting engagement with stop means formed in the rear portion of said solenoid assembly, the improvement comprising: a rearwardly facing annular shoulder formed in said solenoid assembly and a radially outwardly extending annular flange formed on the periphery of said solenoid armature, said disc-like spring member comprising single circular disc having a continuous annular peripheral portion bearing against said rearwardly facing annular shoulder and having a plurality of mutually independent spoke portions extending radially inwardly from the annular peripheral portion, said spoke portions having inner end edges aligned to cooperatively define a central opening for fitting engagement with the flange of said solenoid armature but not fixed thereto.
Claim 2
Dependent Claim
165 words
In a print wire actuating device for a dot matrix type printer, of the type which includes a solenoid assembly comprising a plunger type solenoid armature having a print wire fixed to the front end thereof in aligned relation therewith and a disc-like spring member supporting said solenoid armature and normally biasing said solenoid armature rearwardly into abutting engagement with stop means formed in the rear portion of said solenoid assembly, the improvement comprising: a rearwardly facing annular shoulder formed in said solenoid assembly and a radially outwardly extending annular flange formed on the periphery of said solenoid armature, said disc-like spring member comprising single circular disc having a continuous annular peripheral portion bearing against said rearwardly facing annular shoulder and having a plurality of mutually independent spoke portions extending radially inwardly from the annular peripheral portion, said spoke portions having inner end edges aligned to cooperatively define a central opening for fitting engagement with the flange of said solenoid armature but not fixed thereto.
Claim 3
Dependent Claim
78 words
A print wire actuating device as set forth in claim 1, in which said solenoid armature has a forwardly tapered truncated conical front end portion and said solenoid assembly further comprises a stationary stem member formed with an axially aligned opening for passage of the print wire therethrough and having a rearwardly tapered truncated conical projection formed on the rear side thereof and positioned in aligned opposing relation to said conical front end portion of said solenoid armature.
Claim 4
Dependent Claim
202 words
In a print wire actuating device for a dot matrix type printer, of the type which includes a solenoid assembly comprising a plunger type solenoid armature having a print wire fixed to the front end thereof in aligned relation therewith and a disc-like spring member supporting said solenoid armature and normally biasing said solenoid armature rearwardly into abutting engagement with stop means formed in the rear portion of said solenoid assembly, the improvement comprising: a rearwardly facing annular shoulder formed in said solenoid assembly; a radially outwardly extending annular flange formed on the periphery of said solenoid armature, said disc-like spring member comprising a single circular disc having a continuous annular peripheral outer portion bearing against said rearwardly facing annular shoulder and having an inner portion engaging the flange of said solenoid armature but not fixed thereto; said solenoid armature having a forwardly tapered truncated conical front end portion and said solenoid assembly further comprising a stationary stem member formed with an axially aligned opening for passage of the print wire therethrough and having a rearwardly tapered truncated conical projection formed on the rear side thereof and positioned in aligned opposing relation to said conical front end portion of said solenoid armature.
Claim 5
Dependent Claim
202 words
In a print wire actuating device for a dot matrix type printer, of the type which includes a solenoid assembly comprising a plunger type solenoid armature having a print wire fixed to the front end thereof in aligned relation therewith and a disc-like spring member supporting said solenoid armature and normally biasing said solenoid armature rearwardly into abutting engagement with stop means formed in the rear portion of said solenoid assembly, the improvement comprising: a rearwardly facing annular shoulder formed in said solenoid assembly; a radially outwardly extending annular flange formed on the periphery of said solenoid armature, said disc-like spring member comprising a single circular disc having a continuous annular peripheral outer portion bearing against said rearwardly facing annular shoulder and having an inner portion engaging the flange of said solenoid armature but not fixed thereto; said solenoid armature having a forwardly tapered truncated conical front end portion and said solenoid assembly further comprising a stationary stem member formed with an axially aligned opening for passage of the print wire therethrough and having a rearwardly tapered truncated conical projection formed on the rear side thereof and positioned in aligned opposing relation to said conical front end portion of said solenoid armature.
Claim 6
Dependent Claim
54 words
The device of claim 3 including a space between the adjacent opposed tapered ends said space being a distance greater than the throw of said print wire whereby the print wire impacts a paper document and returns towards the rest position under control of the spring without the adjacent tapered ends coming into engagement.
Claim 7
Dependent Claim
55 words
The device of claim 4 further comprising a solenoid having a hollow interior axially aligned with the print wire, at least the rear portion of the hollow interior having a taper conforming to that of the armature to permit unimpeded movement of the armature extending into the opening in the rear portion of said solenoid.
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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) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |