US3857293A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Timer
Assignee: Emerson Electric Co
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Filing: 1974-02-07
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Granted: 1974-12-31
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Expires: 1994-02-07
Abstract
Abstract There is provided a timing device of the type suitable for controlling the cycling of appliances and the like. The timing device employs a known type of switching cam and switch elements. A drive is provided for the switching cam which provides for slow or normal advance of the cam. More specifically, the drive system employs two pawls each of which is advanced independently by means of drive cams. The pawls are provided with short and normal strokes. Each pawl engages separate ratchet teeth in the switching cam. At the time it is desired to have the shorter stroke pawl assume the function of advancing the switching cam, the ratchet teeth for the large advance parl are omitted from the switching cam and this longer stroke pawl then merely moves on the surface of the cam until ratchet teeth are again provided for it to function.
Inventors
- 👤 G Godwin
- 👤 W Wagle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:14
CPC Classifications
H; H01; H01H; H01H43/00; H01H43/10; H01H43/101; H01H43/102; F; F16; F16H; F16H31/00; F16H31/003; F16H31/004; Y; Y10; Y10T; Y10T74/00; Y10T74/15; Y10T74/1503; Y10T74/1508; Y10T74/1511; Y10T74/1518; Y10T74/1523; Y10T74/21; Y10T74/2101; Y10T74/2102; Y10T74/2106; Y10T74/2133; Y10T74/2141
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
128 words
A multispeed drive mechanism for a timing device and the like comprising: a control cam for connection to a timer shaft; a first ratchet track in the periphery of said control cam having ratchet teeth for slow speed roation of said control cam; a second ratchet track in the periphery of said control cam being segmented to provide ratchet teeth and smooth areas and having a pitch of a multiple of the pitch of the first set of ratchet teeth; first and second pawls operatively associated respectively with said first and second sets of ratchet teeth;and pawl drive means operatively associated with the first and second pawls to advance and retract said pawls synchronously, each through a stroke a distance equal the pitch of its associated ratchet teeth.
Claim 2
Dependent Claim
128 words
A multispeed drive mechanism for a timing device and the like comprising: a control cam for connection to a timer shaft; a first ratchet track in the periphery of said control cam having ratchet teeth for slow speed roation of said control cam; a second ratchet track in the periphery of said control cam being segmented to provide ratchet teeth and smooth areas and having a pitch of a multiple of the pitch of the first set of ratchet teeth; first and second pawls operatively associated respectively with said first and second sets of ratchet teeth;and pawl drive means operatively associated with the first and second pawls to advance and retract said pawls synchronously, each through a stroke a distance equal the pitch of its associated ratchet teeth.
Claim 3
Dependent Claim
52 words
A drive mechanism as set forth in claim 1 wherein each of said pawls is provided with a yoke follower and said pawl drive means includes a continuously driven combination cam and gear including a short stroke cam and a long stroke cam received respectively within the yoke followers of said pawls.
Claim 4
Dependent Claim
44 words
A drive mechanism as set forth in claim 1 wherein said control cam is additionally provided with gear teeth in its periphery, and further including an additional drive means having a final drive gear operatively associated with the gear teeth of said control cam.
Claim 5
Dependent Claim
35 words
A drive mechanism as set forth in claim 1 wherein each of said pawls if formed of resilient material and includes an integrally formed spring biasing the pawl into engagement with its respective ratchet teeth.
References Cited (Backward Citations)
US3310989A
Cited
US3738185A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |