Patent US3670647A successfully refreshed from Google Patents.
US3670647A
Expired / Lapsed
US
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Method of damping rebound of print hammer
Assignee: Unisys Corp
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Filing: 1969-11-20
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Granted: 1972-06-20
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Expires: 1989-11-20
Abstract
Abstract A method of oscillation-free print hammer and return is provided in an apparatus having an inertial hammer, a relay and a resilient backstop. In this method the armature of the relay is pivotably mounted and imparts motion to the hammer. The solenoid of the relay physically restrains the motion of the armature and then holds the armature by residual magnetism. The hammer continues in inertial flight until it reaches the printing area. On rebound the hammer strikes the armature and part of the kinetic energy of the hammer is absorbed as the hammer drives the armature free from the residual magnetic field. The armature and hammer continue to the backstop which absorbs or dissipates the remainder of the kinetic energy. The absorption of kinetic energy is for damping hammer oscillations and permits higher frequency of operation.
Inventors
- 👤 John W Funk
- 👤 Kishor M Lakhani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:26
CPC Classifications
B; B41; B41J; B41J9/00; B41J9/26; B41J9/38; B41J9/42
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
160 words
A method of damping the rebound of an inertial print hammer to prevent secondary rebound, in a print hammer apparatus having an inertial hammer mounted for actuation from an inoperative position to a print position and rebound to the inoperative position, and a magnetic core electromagnetic relay having an armature, said armature being the actuator for said hammer and being biased to an inoperative position, comprising: supplying current to said relay for attracting said armature and actuating said hammer; eliminating current from said relay before the rebound of said hammer; passively holding said armature in the path of rebound of said hammer by the residual magnetism of said relay; impacting said rebounding hammer against said magnetically held armature and breaking said armature from the residual magnetic bonds to absorb a portion of the kinetic energy of the rebounding hammer; and resiliently damping the balance of the kinetic energy of the rebounding hammer upon said hammer''s return to the inoperative position.
Claim 2
Independent Claim
160 words
A method of damping the rebound of an inertial print hammer to prevent secondary rebound, in a print hammer apparatus having an inertial hammer mounted for actuation from an inoperative position to a print position and rebound to the inoperative position, and a magnetic core electromagnetic relay having an armature, said armature being the actuator for said hammer and being biased to an inoperative position, comprising: supplying current to said relay for attracting said armature and actuating said hammer; eliminating current from said relay before the rebound of said hammer; passively holding said armature in the path of rebound of said hammer by the residual magnetism of said relay; impacting said rebounding hammer against said magnetically held armature and breaking said armature from the residual magnetic bonds to absorb a portion of the kinetic energy of the rebounding hammer; and resiliently damping the balance of the kinetic energy of the rebounding hammer upon said hammer''s return to the inoperative position.
Claim 3
Dependent Claim
55 words
The method of claim 1 additionally including the stop of resiliently biasing said hammer against said armature when each is in its inoperative position; and wherein the step of resiliently damping the balance of the kinetic energy of the rebounding hammer includes the step of distorting a butyl rubber member in both shear and compression.
Claim 4
Dependent Claim
36 words
The method of claim 2 also including after the step of energizing the step of spacing the energized position of said armature away from said core for preventing said armature from magnetically locking with said 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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |