US3717043A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Timer stepping mechanism having stretched intervals
Assignee: Eaton Corp
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Filing: 1971-10-01
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Granted: 1973-02-20
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Expires: 1991-10-01
Abstract
Abstract The continuously driven drive disc has a crank provided with a drive pawl on one end and a depending finger or feeler on the other end. A retracting lever is also carried by the drive disc and includes a depending cam portion which is adapted to engage a splitter fixed on the end plate of the timer. A single spring acts on the lever to force it against the pawl crank to hold the pawl in retracted position against the bias of the same spring acting on the pawl in the engaging direction. However, when the cam depending from the positioning lever engages the splitter the retracting lever is moved to a position allowing the pawl to move into engagement with the ratchet teeth on the inside of the timing cam drum. Initially, however, the pawl is prevented from moving into contact with the ratchet teeth due to a portion of the crank engaging the splitter. When the sensing portion of the crank drops off of the splitter the spring force drives the pawl towards the ratchet. In one version this causes the pawl to engage the teeth and drive the timing cam drum until the cam depending from the lever clears the splitter, at which time the net spring force returns the pawl to a retracted position as the spring returns the lever to its restraining position. In another version the feeler portion of the pawl crank may engage a mask carried by the drive disc and prevent the pawl from engaging the ratchet teeth, thus prolonging the interval until the mask has been moved out of its blocking position. Selective use of this interval extending concept is achieved by making some of the ratchet teeth longer than others so that even if the mask is in the blocking position the pawl can reach a tooth and index the timing cam. Spacing of the teeth can be varied so long as the longest interval does not exceed any two adjacent small steps. The long tooth, short tooth, and variable step features may be combined in a different ratchet configuration. The mask may be mounted on a plate which can be actuated on each step to disengage the mask from the drive disc and permit a return spring to return the mask to a zero position to insure full availability of the interval stretching feature.
Inventors
- 👤 R Cartier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:59
CPC Classifications
F; F16; F16H; F16H31/00; F16H31/003; F16H31/004; H; H01; H01H; H01H43/00; H01H43/10; H01H43/101; H01H43/102; Y; Y10; Y10T; Y10T74/00; Y10T74/11; Y10T74/114; Y10T74/115; Y10T74/15; Y10T74/1503; Y10T74/21; Y10T74/2101; Y10T74/2102; Y10T74/2106
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
245 words
In a timer a motor, a drive disc continuously driven by said motor, a timing cam provided with ratchet teeth, a pawl pivotally mounted on the disc for movement between a retracted position and an operative position in which it engages said ratchet teeth to transmit motion from the disc to the timing cam, a lever pivotally supported on the disc and having a portion interposed between the pawl and the ratchet whereby the lever may be moved to an operative position in which it moves the pawl to its retracted position, a cam portion on said lever, stationary means engageable by the cam portion and operative to move the lever to its inoperative position as the disc rotates, stop means carried by the pawl, second stationary means operative to engage said stop means and prevent movement of the pawl towards the ratchet so long as the stop means is engaged with the second stationary means, a spring acting on both the pawl and the lever and exerting a greater force on the lever than on the pawl so that absent other controlling factors the lever is biased to its active position in which the pawl is retracted, said spring being operative to exert sufficient bias on the pawl to drive the pawl into operative engagement with the ratchet with a snap action when the pawl is not restrained either by the lever or by engagement of the stop means with saiD second stationary means.
Claim 2
Dependent Claim
245 words
In a timer a motor, a drive disc continuously driven by said motor, a timing cam provided with ratchet teeth, a pawl pivotally mounted on the disc for movement between a retracted position and an operative position in which it engages said ratchet teeth to transmit motion from the disc to the timing cam, a lever pivotally supported on the disc and having a portion interposed between the pawl and the ratchet whereby the lever may be moved to an operative position in which it moves the pawl to its retracted position, a cam portion on said lever, stationary means engageable by the cam portion and operative to move the lever to its inoperative position as the disc rotates, stop means carried by the pawl, second stationary means operative to engage said stop means and prevent movement of the pawl towards the ratchet so long as the stop means is engaged with the second stationary means, a spring acting on both the pawl and the lever and exerting a greater force on the lever than on the pawl so that absent other controlling factors the lever is biased to its active position in which the pawl is retracted, said spring being operative to exert sufficient bias on the pawl to drive the pawl into operative engagement with the ratchet with a snap action when the pawl is not restrained either by the lever or by engagement of the stop means with saiD second stationary means.
Claim 3
Dependent Claim
245 words
In a timer a motor, a drive disc continuously driven by said motor, a timing cam provided with ratchet teeth, a pawl pivotally mounted on the disc for movement between a retracted position and an operative position in which it engages said ratchet teeth to transmit motion from the disc to the timing cam, a lever pivotally supported on the disc and having a portion interposed between the pawl and the ratchet whereby the lever may be moved to an operative position in which it moves the pawl to its retracted position, a cam portion on said lever, stationary means engageable by the cam portion and operative to move the lever to its inoperative position as the disc rotates, stop means carried by the pawl, second stationary means operative to engage said stop means and prevent movement of the pawl towards the ratchet so long as the stop means is engaged with the second stationary means, a spring acting on both the pawl and the lever and exerting a greater force on the lever than on the pawl so that absent other controlling factors the lever is biased to its active position in which the pawl is retracted, said spring being operative to exert sufficient bias on the pawl to drive the pawl into operative engagement with the ratchet with a snap action when the pawl is not restrained either by the lever or by engagement of the stop means with saiD second stationary means.
Claim 4
Dependent Claim
245 words
In a timer a motor, a drive disc continuously driven by said motor, a timing cam provided with ratchet teeth, a pawl pivotally mounted on the disc for movement between a retracted position and an operative position in which it engages said ratchet teeth to transmit motion from the disc to the timing cam, a lever pivotally supported on the disc and having a portion interposed between the pawl and the ratchet whereby the lever may be moved to an operative position in which it moves the pawl to its retracted position, a cam portion on said lever, stationary means engageable by the cam portion and operative to move the lever to its inoperative position as the disc rotates, stop means carried by the pawl, second stationary means operative to engage said stop means and prevent movement of the pawl towards the ratchet so long as the stop means is engaged with the second stationary means, a spring acting on both the pawl and the lever and exerting a greater force on the lever than on the pawl so that absent other controlling factors the lever is biased to its active position in which the pawl is retracted, said spring being operative to exert sufficient bias on the pawl to drive the pawl into operative engagement with the ratchet with a snap action when the pawl is not restrained either by the lever or by engagement of the stop means with saiD second stationary means.
Claim 5
Dependent Claim
111 words
A step-by-step timer comprising a motor, a disc continuously driven by the motor, a timing cam rotatable about the same axis as the disc and including a ratchet, a pawl carried by the disc, means for cyclically actuating the pawl towards said ratchet teeth for a discreet number of degrees of rotation whereby the timing cam is rotated the same number of degrees when the pawl is in engagement with the ratchet, and means for limiting the movement of the pawl towards the ratchet whereby the pawl is prevented from engaging the ratchet for a predetermined number of pawl actuations whereby the interval between advances of the timing cam is increased.
Claim 6
Dependent Claim
111 words
A step-by-step timer comprising a motor, a disc continuously driven by the motor, a timing cam rotatable about the same axis as the disc and including a ratchet, a pawl carried by the disc, means for cyclically actuating the pawl towards said ratchet teeth for a discreet number of degrees of rotation whereby the timing cam is rotated the same number of degrees when the pawl is in engagement with the ratchet, and means for limiting the movement of the pawl towards the ratchet whereby the pawl is prevented from engaging the ratchet for a predetermined number of pawl actuations whereby the interval between advances of the timing cam is increased.
Claim 7
Dependent Claim
46 words
Apparatus according to claim 2 in which the pawl includes a feeler portion and the motion limiting means includes a masking member which obstructs movement of the feeler portion, said mask being movable to an inoperative position after a predetermined number of revolutions of the disc.
Claim 8
Dependent Claim
86 words
Apparatus according to claim 2 in which the ratchet teeth lie on at least two radii whereby the teeth on the longer radius cannot be engaged by the pawl when said mask is operative but can be engaged by the pawl when the mask is inoperative, the teeth on the shorter radius being engageable by said pawl whether or not the mask is operative thus allowing the interval between stepping motion of the timing cam to be increased at selected angular positions of the timing cam.
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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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |