US3871159A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safety device for lawnmowers
Assignee: Individual
•
Filing: 1973-08-17
•
Granted: 1975-03-18
•
Expires: 1993-08-17
Abstract
Abstract In a rotary lawnmower, a clutch operable when engaged to connect the prime mover to the blade to drive it, a brake operable when engaged to resist rotation of the blade, springs normally maintaining the clutch disengaged and the brake engaged, manually operable mechanism operable by a normal grip of the human operator on the handlebar to disengage the brake and engage the clutch, and automatic mechanism operable by raising of the handlebar to render said manually operable mechanism ineffective.
Inventors
- 👤 Charles R Shriver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:53
CPC Classifications
A; A01; A01D; A01D34/00; A01D34/01; A01D34/412; A01D34/63; A01D34/67; A01D34/68; A01D34/6806; A01D34/6812; F; F16; F16D; F16D67/00; F16D67/02; A01D2101/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
308 words
In a lawnmower including a base housing, a prime mover mounted on said housing and including a rotatably driven drive shaft, a blade operable to be driven by said prime mover, said blade being carried by a blade shaft mounted rotatably in said housing, coaxially with and below said drive shaft, and propelling means including a handlebar connected to said housing and having a hand grip adapted to be grasped by the operator, safety means comprising: a. a first clutch disc fixed on said drive shaft concentrically therewith, b. a first brake disc fixed in said housing concentrically with said shafts and spaced below said first clutch disc, c. a spool member mounted on said blade shaft between said first clutch and brake discs, said spool member being axially slidable on said blade shaft but restrained against rotation relative thereto, and including at its upper end a second clutch disc engageable with said first clutch disc, and at its lower end a second brake disc engageable with said first brake disc, the spacing between the operative faces of said second clutch and brake discs being less than the spacing between the operative faces of said first clutch and brake discs, d. resilient biasing means operable to urge said spool member downwardly whereby said brake discs are engaged and said clutch discs are disengaged, and e. manually operable means operable to elevate said spool member against said resilient means whereby said brake discs are disengaged and said clutch discs are engaged, said manually operable means including a grip lever pivotally mounted on said handlebar adjacent said hand grip, said lever being adapted to be engaged and pivoted by the operator with the hand he uses to grasp said hand grip, whereby the lever is released, and the spool member is moved downwardly, whenever the operator releases said hand grip.
Claim 2
Dependent Claim
308 words
In a lawnmower including a base housing, a prime mover mounted on said housing and including a rotatably driven drive shaft, a blade operable to be driven by said prime mover, said blade being carried by a blade shaft mounted rotatably in said housing, coaxially with and below said drive shaft, and propelling means including a handlebar connected to said housing and having a hand grip adapted to be grasped by the operator, safety means comprising: a. a first clutch disc fixed on said drive shaft concentrically therewith, b. a first brake disc fixed in said housing concentrically with said shafts and spaced below said first clutch disc, c. a spool member mounted on said blade shaft between said first clutch and brake discs, said spool member being axially slidable on said blade shaft but restrained against rotation relative thereto, and including at its upper end a second clutch disc engageable with said first clutch disc, and at its lower end a second brake disc engageable with said first brake disc, the spacing between the operative faces of said second clutch and brake discs being less than the spacing between the operative faces of said first clutch and brake discs, d. resilient biasing means operable to urge said spool member downwardly whereby said brake discs are engaged and said clutch discs are disengaged, and e. manually operable means operable to elevate said spool member against said resilient means whereby said brake discs are disengaged and said clutch discs are engaged, said manually operable means including a grip lever pivotally mounted on said handlebar adjacent said hand grip, said lever being adapted to be engaged and pivoted by the operator with the hand he uses to grasp said hand grip, whereby the lever is released, and the spool member is moved downwardly, whenever the operator releases said hand grip.
Claim 3
Dependent Claim
92 words
The structure as recited in claim 1 wherein said resilient biasing means includes a control lever pivoted in said housing and having at one end a connection to said spool member permitting rotation of said spool member, said lever being operable by pivotal movement in a first direction to lower said spool member, and by movement in a second direction to elevate said spool member, and a spring operable to bias said lever in said first direction, said manually operable means being operable to pivot said control lever in said second direction.
Claim 4
Dependent Claim
51 words
The structure as recited in claim 2 wherein said handlebar is pivotally connected to said housing for vertical movement, and wherein said manually operable means includes a flexible strand interconnecting said control lever to said hand grip lever, said strand having sufficient slack therein to permit vertical movement of said handlebar.
Claim 5
Dependent Claim
109 words
The structure as recited in claim 3 with the addition of a second control lever pivoted to said housing and having one end thereof connected to the end of said flexible strand connected to said first control lever, and operable when pivoted in one direction to apply a tension to said strand opposite to the tension applied thereto by said hand grip lever, and a second flexible strand interconnecting the opposite end of said second control lever to said handlebar, whereby whenever said handlebar is pivoted upwardly to a pre-determined degree, said second flexible strand applies a force tending to pivot said second control lever in said one direction.
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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |