Patent US3731471A successfully refreshed from Google Patents.
US3731471A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safe starting system for lawn and garden equipment
Assignee: Deere and Co
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Filing: 1972-03-22
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Granted: 1973-05-08
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Expires: 1992-03-22
Abstract
Abstract A riding mower has an internal combustion engine with a magneto type ignition system and a recoil starter. A mower is suspended from the tractor and driven from the engine through a belt drive, which includes a clutch, while the traction wheels are driven through a different drive system, which also includes a clutch. A pair of parallel connected switches are respectively connected to the clutches so that they close when the clutches are engaged, and the switches are connected to the magneto primary coil and a normally closed centrifugal switch, which is disposed between the engine flywheel and the recoil starting mechanism and opens only when the engine reaches a predetermined speed. When the centrifugal switch is closed and either of the clutch switches are closed, the magneto primary is shorted to ground, preventing the starting of the engine when either of the clutches is engaged. When the engine reaches the predetermined speed, the centrifugal switch opens, so that either clutch can be engaged without shorting out the magneto primary coil.
Inventors
- 👤 C Bening
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:33
CPC Classifications
A; A01; A01D; A01D34/00; A01D34/01; A01D34/412; A01D34/63; A01D34/82; A01D34/828; A01D34/67; A01D34/68; A01D34/6806; A01D34/6818; Y; Y10; Y10S; Y10S56/00; Y10S56/15
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
159 words
In a lawn and garden machine having a mobile main frame, an internal combustion engine having an ignition system, a working tool and means for drivingly connecting the engine to the working tool and including a clutch means selectively engageable and disengageable to respectively establish or disestablish the driving connection, the improvement compriSing: a first switch means operatively connected to and responsive to the condition of the clutch means so that it is open when the clutch means is disengaged and closed when the clutch means is engaged; a normally closed centrifugal switch means operatively mounted on the engine and shiftable into an open condition when the engine speed exceeds a predetermined value; and electrical conductor means operatively connecting the first switch means and centrifugal switch means in series between the ignition and ground to short the ignition system when both switch means are closed and thereby prevent the engine from being started when the clutch means is engaged.
Claim 2
Dependent Claim
159 words
In a lawn and garden machine having a mobile main frame, an internal combustion engine having an ignition system, a working tool and means for drivingly connecting the engine to the working tool and including a clutch means selectively engageable and disengageable to respectively establish or disestablish the driving connection, the improvement compriSing: a first switch means operatively connected to and responsive to the condition of the clutch means so that it is open when the clutch means is disengaged and closed when the clutch means is engaged; a normally closed centrifugal switch means operatively mounted on the engine and shiftable into an open condition when the engine speed exceeds a predetermined value; and electrical conductor means operatively connecting the first switch means and centrifugal switch means in series between the ignition and ground to short the ignition system when both switch means are closed and thereby prevent the engine from being started when the clutch means is engaged.
Claim 3
Dependent Claim
42 words
The invention defined in claim 1 wherein the ignition system is of the magneto type and includes a primary coil, the conductor means being connected to the primary coil to short the primary coil to ground when both switch means are closed.
Claim 4
Dependent Claim
104 words
The invention defined in claim 1 wherein the machine includes drive wheel means and means for drivingly connecting the engine to the drive wheel means and including a second clutch means selectively engageable and disengageable to respectively establish and disestablish the driving connection, and including a second switch means connected in parallel with the first switch means and responsive to the condition of the second clutch means so that it respectively opens and closes in response to disengagement and engagement of the clutch means, to short the ignition system when either clutch means is engaged and the engine is rotated below said predetermined speed.
Claim 5
Dependent Claim
38 words
The invention defined in claim 3 wherein the working tool is a mower unit and the first clutch means is disposed in the mower drive to prevent the engine from being started when the mower drive is engaged.
Claim 6
Dependent Claim
69 words
The invention defined in claim 1 wherein the engine includes a recoil starter and a flywheel and the centrifugal switch means includes a shiftable arm connected to and rotatable with the flywheel and biased toward engagement with the recoil starter, the arm being swingable out of engagement with the recoil starter in response to centrifugal force when the flywheel speed exceeds said predetermined value to open said switch means.
Claim 7
Dependent Claim
166 words
In a machine having a mobile main frame, an internal combustion engine mounted on the frame and having a magneto ignition system with a primary coil, a driven element, and means drivingly connecting the engine to the driven element and including a clutch means selectively engageable and disengageable to respectively establish or disestablish the driving connection, the improvement comprising: a first switch means mounted on the frame and operatively connected to the clutch means to respectively open and close in response to disengagement and engagement of the clutch means; a normally closed centrifugal switch means operatively mounted on a rotating engine element for shifting to an open condition in response to centrifugal force when the rotating element reaches a predetermined speed; and a grounded electrical conductor means operatively connecting the centrifugal switch means and the first switch means in series to the magneto primary coil so that the primary coil is shorted to ground when the first switch means and the centrifugal switch means are closed.
Claim 8
Dependent Claim
166 words
In a machine having a mobile main frame, an internal combustion engine mounted on the frame and having a magneto ignition system with a primary coil, a driven element, and means drivingly connecting the engine to the driven element and including a clutch means selectively engageable and disengageable to respectively establish or disestablish the driving connection, the improvement comprising: a first switch means mounted on the frame and operatively connected to the clutch means to respectively open and close in response to disengagement and engagement of the clutch means; a normally closed centrifugal switch means operatively mounted on a rotating engine element for shifting to an open condition in response to centrifugal force when the rotating element reaches a predetermined speed; and a grounded electrical conductor means operatively connecting the centrifugal switch means and the first switch means in series to the magneto primary coil so that the primary coil is shorted to ground when the first switch means and the centrifugal switch means are closed.
Claim 9
Dependent Claim
22 words
The invention defined in claim 6 wherein the engine includes a flywheel, and the centrifugal switch means is mounted on the flywheel.
Claim 10
Dependent Claim
69 words
The invention defined in claim 6 wherein the engine includes a recoil starter and a flywheel and the centrifugal switch means includes a shiftable arm connected to and rotatable with the flywheel and biased toward engagement with the recoil starter, the arm being swingable out of engagement with the recoil starter in response to centrifugal force when the flywheel speed exceeds said predetermined value to open said switch means.
Claim 11
Dependent Claim
38 words
The invention defined in claim 6 wherein the driven element comprises a mower unit and the first clutch means is disposed in the mower unit drive to preveNt the engine from starting when the mower drive is engaged.
Claim 12
Dependent Claim
104 words
The invention defined in claim 9 wherein the machine includes drive wheel means and means for drivingly connecting the engine to the drive wheel means and including a second clutch means selectively engageable and disengageable to respectively establish and disestablish the driving connection, and including a second switch means connected in parallel with the first switch means and responsive to the condition of the second clutch means so that it respectively opens and closes in response to disengagement and engagement of the clutch means, to short the ignition system when either clutch meanS is engaged and the engine is rotated below said predetermined speed.
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) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |