US3645373A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Escapement mechanism
Assignee: Singer Co
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Filing: 1969-05-21
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Granted: 1972-02-29
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Expires: 1989-05-21
Abstract
Abstract A rigid unitary escapement pawl is provided which has first and second pawl tines which may be alternately engaged with a tooth of an escapement wheel during an escape operation. The unitary structure includes first and second stops which coact with the sides of an escapement wheel to limit the pivotal motion of the structure during an escape cycle of operation. One of the stops provides added rigidity and strength to the associated pawl tine.
Inventors
- 👤 Richard W Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:38
CPC Classifications
B; B41; B41J; B41J19/00; B41J19/18; B41J19/34; B41J19/40
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
280 words
In a typewriter escapement mechanism: a. a toothed escapement member; b. first bias means biasing said toothed escapement member for rotational motion in a first direction; c. a unitary bifurcated pawl assembly comprising a first pawl having a tooth angle, a second pawl, each of said pawls having an individual engaging area for selectively engaging a tooth of said toothed escapement member for restraining the motion of said toothed escapement member, d. said unitary bifurcated pawl assembly supported for reciprocal pivotal motion for the selective engagement of the engaging area of said first and second pawls with a tooth of said toothed escapement member and with the axis of said pivotal motion parallel to the effective bias force of said toothed escapement member at the point of contact between the engaging area of said first pawl and said toothed escapement member, e. second bias means for urging the pivotal motion of said unitary bifurcated pawl assembly in one direction, f. first pivot limiting means consisting of an extended portion of said first pawl and continuous with said first pawl and cooperating with said toothed escapement member for restricting the extent of pivotal excursion of said unitary bifurcated pawl assembly in said one direction, and for imparting support and strength to the tooth angle of said first pawl, g. second pivot limiting means consisting of an arm of said unitary bifurcated pawl assembly to cooperate with said toothed escapement member for restricting the extent of pivotal excursion of said unitary bifurcated pawl assembly in a direction opposite to said one direction, and h. control means for selectively pivoting said unitary bifurcated pawl assembly in a direction opposite to said one direction.
Claim 2
Dependent Claim
280 words
In a typewriter escapement mechanism: a. a toothed escapement member; b. first bias means biasing said toothed escapement member for rotational motion in a first direction; c. a unitary bifurcated pawl assembly comprising a first pawl having a tooth angle, a second pawl, each of said pawls having an individual engaging area for selectively engaging a tooth of said toothed escapement member for restraining the motion of said toothed escapement member, d. said unitary bifurcated pawl assembly supported for reciprocal pivotal motion for the selective engagement of the engaging area of said first and second pawls with a tooth of said toothed escapement member and with the axis of said pivotal motion parallel to the effective bias force of said toothed escapement member at the point of contact between the engaging area of said first pawl and said toothed escapement member, e. second bias means for urging the pivotal motion of said unitary bifurcated pawl assembly in one direction, f. first pivot limiting means consisting of an extended portion of said first pawl and continuous with said first pawl and cooperating with said toothed escapement member for restricting the extent of pivotal excursion of said unitary bifurcated pawl assembly in said one direction, and for imparting support and strength to the tooth angle of said first pawl, g. second pivot limiting means consisting of an arm of said unitary bifurcated pawl assembly to cooperate with said toothed escapement member for restricting the extent of pivotal excursion of said unitary bifurcated pawl assembly in a direction opposite to said one direction, and h. control means for selectively pivoting said unitary bifurcated pawl assembly in a direction opposite to said one direction.
Claim 3
Dependent Claim
52 words
The combination as set forth in claim 1 wherein said individual engaging area of said first and second pawls are spaced apart in the direction of rotational motion of said toothed escapement member a distance equal to that of approximately half of the pitch between successive teeth on said toothed escapement member.
Claim 4
Dependent Claim
244 words
In a typewriter escapement mechanism: a. a toothed escapement wheel; b. first bias means biasing said toothed escapement wheel for rotation in a first direction about its axis, c. a retaining pawl having a tooth angle, an escapement pawl, each of said pawls having an individual engaging area for alternately engaging a tooth of said toothed escapement wheel during an escape cycle; d. said retaining and escapement pawls joined in cooperative relationship to form a unitary bifurcated pawl assembly for limited pivotal motion about an axis in the plane of said toothed escapement wheel, e. first and second pivot limiting means cooperative with said unitary bifurcated pawl assembly and with said toothed escapement wheel for limiting the pivotal motion of said unitary bifurcated pawl assembly so that at least part of one of said individual engaging areas is always in the plane of said toothed escapement wheel, f. said individual engaging areas displaced from each other in said first direction of rotation of said toothed escapement wheel for permitting said toothed escapement wheel to rotate through an angle equal to approximately one-half the angle between identical points on successive teeth of said toothed escapement wheel when said unitary bifurcated pawl assembly is pivoted from one limit to the other, and wherein g. said first pivot limiting means consists of an extended portion of said retaining pawl which is continuous therewith and which provides support and strength for said tooth angle of said retaining pawl.
Claim 5
Dependent Claim
244 words
In a typewriter escapement mechanism: a. a toothed escapement wheel; b. first bias means biasing said toothed escapement wheel for rotation in a first direction about its axis, c. a retaining pawl having a tooth angle, an escapement pawl, each of said pawls having an individual engaging area for alternately engaging a tooth of said toothed escapement wheel during an escape cycle; d. said retaining and escapement pawls joined in cooperative relationship to form a unitary bifurcated pawl assembly for limited pivotal motion about an axis in the plane of said toothed escapement wheel, e. first and second pivot limiting means cooperative with said unitary bifurcated pawl assembly and with said toothed escapement wheel for limiting the pivotal motion of said unitary bifurcated pawl assembly so that at least part of one of said individual engaging areas is always in the plane of said toothed escapement wheel, f. said individual engaging areas displaced from each other in said first direction of rotation of said toothed escapement wheel for permitting said toothed escapement wheel to rotate through an angle equal to approximately one-half the angle between identical points on successive teeth of said toothed escapement wheel when said unitary bifurcated pawl assembly is pivoted from one limit to the other, and wherein g. said first pivot limiting means consists of an extended portion of said retaining pawl which is continuous therewith and which provides support and strength for said tooth angle of said retaining pawl.
Claim 6
Dependent Claim
31 words
The combination as set forth in claim 3 and including second bias means to bias said unitary bifurcated pawl assembly for pivotal motion until limited by said first pivot limiting means.
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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) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |