US4051915A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Neutral start and park brake safety interlock circuitry for a tractor
Assignee: Deere and Co
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Filing: 1976-11-05
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Granted: 1977-10-04
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Expires: 1996-11-05
Abstract
Abstract Electric control circuitry is provided for preventing a tractor engine from being started with the tractor transmission or power take-off engaged and for preventing the tractor from being driven with the park brake engaged. The control circuitry includes normally open power take-off and transmission condition sensing switches connected in series with each other and a starting solenoid and thus defining a portion of a starting circuit. These two switches in the starting circuit are respectively held closed only when a power take-off control lever is in a clutch-disengage position and the transmission shift lever is in a neutral position. The control circuitry also includes a second normally open transmission condition sensing switch connected in parallel with a normally open park brake condition sensing switch, these two switches being in series with the ignition coil and thus defining a portion of an ignition circuit. Also, these two switches are respectively held closed only when the transmission shift lever is in its neutral position and a brake pedal locking pawl is in a pedal-release position.
Inventors
- 👤 Robert Nick Behrens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:56
CPC Classifications
B; B60; B60K; B60K28/00; B60K28/10; B60W; B60W2510/00; B60W2510/02; B60W2510/0208; Y; Y10; Y10T; Y10T74/00; Y10T74/20; Y10T74/20012; Y10T74/20018; Y10T74/20085
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
342 words
In combination with a lawn and garden tractor including an electrically responsive engine starting means and an ignition means, a transmission shift means movable between neutral-effecting and drive-effecting positions, park brake control means movable between park brake release and park brake engage positions, and a power take-off clutch control means movable between clutch-engage and clutch-disengage positions, a safety interlock circuit, comprising: a source of electric energy; an ignition switch means connected to the source; a starting circuit including a first lead means connected between the ignition switch means and the engine starting means; a normally open power take-off clutch condition responsive switch means mounted for actuation to a closed position by the clutch control means only when the latter is moved to its clutch-disengage position; a first normally open transmission condition responsive switch means mounted for actuation to a closed position by the transmission shift means only when the latter is moved to its neutral-effecting position; said clutch condition responsive switch means and first transmission condition responsive switch means being connected between the ignition switch means and the engine starting means in the first lead means in series with each other and with the ignition switch means and the engine starting means; an ignition circuit including a second lead means connected to the ignition switch means and the ignition means; a second normally open transmission condition responsive switch means mounted for actuation to a closed position by the transmission shift means only when the latter is moved to it neutral-effecting position; a normally open park-brake condition responsive switch means mounted for actuation to a closed position by the park brake control means only when the latter is moved to its park brake disengage position; and said second transmission condition responsive switch means and said park brake condition responsive switch means being connected in said second lead means between the ignition switch means and the ignition means in parallel to each other, whereby the tractor cannot be started with the transmission or power take-off clutch engaged or driven with the park brake engaged.
Claim 2
Dependent Claim
342 words
In combination with a lawn and garden tractor including an electrically responsive engine starting means and an ignition means, a transmission shift means movable between neutral-effecting and drive-effecting positions, park brake control means movable between park brake release and park brake engage positions, and a power take-off clutch control means movable between clutch-engage and clutch-disengage positions, a safety interlock circuit, comprising: a source of electric energy; an ignition switch means connected to the source; a starting circuit including a first lead means connected between the ignition switch means and the engine starting means; a normally open power take-off clutch condition responsive switch means mounted for actuation to a closed position by the clutch control means only when the latter is moved to its clutch-disengage position; a first normally open transmission condition responsive switch means mounted for actuation to a closed position by the transmission shift means only when the latter is moved to its neutral-effecting position; said clutch condition responsive switch means and first transmission condition responsive switch means being connected between the ignition switch means and the engine starting means in the first lead means in series with each other and with the ignition switch means and the engine starting means; an ignition circuit including a second lead means connected to the ignition switch means and the ignition means; a second normally open transmission condition responsive switch means mounted for actuation to a closed position by the transmission shift means only when the latter is moved to it neutral-effecting position; a normally open park-brake condition responsive switch means mounted for actuation to a closed position by the park brake control means only when the latter is moved to its park brake disengage position; and said second transmission condition responsive switch means and said park brake condition responsive switch means being connected in said second lead means between the ignition switch means and the ignition means in parallel to each other, whereby the tractor cannot be started with the transmission or power take-off clutch engaged or driven with the park brake engaged.
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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) | 1980-10-03 | 1981-04-04 | 1981-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-03 | 1985-04-04 | 1985-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-03 | 1989-04-04 | 1989-10-04 | $7700.00 | Window Closed / Lapsed |