US3724248A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Timer
Assignee: Eaton Corp
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Filing: 1971-10-07
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Granted: 1973-04-03
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Expires: 1991-10-07
Abstract
Abstract The outer ratchet wheel is a part of the timing cam drum of a step-by-step type of interval timer. The outer ratchet is advanced by means of a pawl which is reciprocated as the slow rise fast drop cam rotates to retract the pawl one tooth and advance the pawl with a snap action until the pawl abuts a stop member, at which time the retaining pawl engages the same tooth to hold the cam in place. At certain intervals or positions on the outer ratchet the teeth are missing thereby allowing the drive pawl (and then the retaining pawl) to ''''reach inside'''' and engage a time delay ratchet which is then advanced inside the outer ratchet a number of steps until the inner ratchet engages the inside of the outer ratchet and starts driving the outer ratchet until the drive pawl and retaining pawl are back onto the outside ratchet, at which time the inside ratchet is released and returned to its original point by the spring bias. This allows what would normally be a short interval on the outer ratchet to be ''''stretched'''' to provide a long interval without consuming too many steps of the timing cam.
Inventors
- 👤 G Obermann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:35
CPC Classifications
H; H01; H01H; H01H43/00; H01H43/10; H01H43/101; H01H43/102; F; F16; F16H; F16H29/00; F16H29/02; Y; Y10; Y10T; Y10T74/00; Y10T74/15; Y10T74/1503; Y10T74/1508; Y10T74/1518; Y10T74/1526; Y10T74/1529; Y10T74/1553; Y10T74/1555; Y10T74/21; Y10T74/2133
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
233 words
A program timer of the type advanced in a step-by-step manner to sequentially actuate switches in accordance with the rotational position of the program cam, comprising, a ratchet wheel having spaced teeth, a stepping mechanism including an advance pawl engageable with the ratchet wheel to advance the ratchet wheel in a step-bystep manner to sequential positions determining the position of the program timing cam, some of the teeth of the ratchet being omitted in at least one position on the periphery of the ratchet so as to leave a gap through which the advancing pawl may project inwardly, a second ratchet wheel positioned inside the first with teeth underlying the gap in the outer ratchet wheel whereby the advancing pawl will operate through the said gap onto the inner ratchet wheel and advance it in a step-by-step manner, said inner ratchet wheel being biased to an initial position and being rotatably relative to the outer ratchet wheel to a second position in which the inner and outer ratchet wheels become engaged and move in unison whereby the timing cam remains stationary during such period as the advancing pawl is advancing the inner ratchet relative to the outer ratchet and upon the two ratchets becoming interengaged the advance pawl returns to the outer ratchet and is disengaged from the inner ratchet which then returns to its initial position under influence of its spring bias.
Claim 2
Dependent Claim
233 words
A program timer of the type advanced in a step-by-step manner to sequentially actuate switches in accordance with the rotational position of the program cam, comprising, a ratchet wheel having spaced teeth, a stepping mechanism including an advance pawl engageable with the ratchet wheel to advance the ratchet wheel in a step-bystep manner to sequential positions determining the position of the program timing cam, some of the teeth of the ratchet being omitted in at least one position on the periphery of the ratchet so as to leave a gap through which the advancing pawl may project inwardly, a second ratchet wheel positioned inside the first with teeth underlying the gap in the outer ratchet wheel whereby the advancing pawl will operate through the said gap onto the inner ratchet wheel and advance it in a step-by-step manner, said inner ratchet wheel being biased to an initial position and being rotatably relative to the outer ratchet wheel to a second position in which the inner and outer ratchet wheels become engaged and move in unison whereby the timing cam remains stationary during such period as the advancing pawl is advancing the inner ratchet relative to the outer ratchet and upon the two ratchets becoming interengaged the advance pawl returns to the outer ratchet and is disengaged from the inner ratchet which then returns to its initial position under influence of its spring bias.
Claim 3
Dependent Claim
74 words
A timer according to claim 1 including holding means operative to engage said outer ratchet during each back step movement of the advancing pawl and thereby prevent movement of the program timing cam in the interval between the advancing steps, second holding means operative on said inner ratchet wheel to retain it in its advanced position relative to the outer ratchet wheel during the interval between advancing steps imparted to the inner ratchet wheel.
Claim 4
Dependent Claim
66 words
Apparatus according to claim 2 in which the holding means for both ratchet wheels are carried by the same member and comprises holding pawls, one of said holding pawls engaging the outer ratchet until it reaches said gap and thereupon engaging the inner ratchet, the other holding pawl being an auxiliary pawl which engages the outer ratchet while the first holding pawl engages the inner ratchet.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |