Safety rotary mower

Claim 2

In a rotary mower having a propeller type blade rotating in a horizontal plane in a wheel supported housing open at the bottom, the improvement comprising: a ring-shaped substantially flat shroud substantially co-axial with the blade and forming an annular chamber for the blade with the bottom periphery of the housing, the inner diameter of the shroud being less than the blade length, and the outer diameter of the shroud protruding beyond the housing, said shroud forming with the ground during mowing a tunnel having a radial extend which is substantially longer than the mowing extent whereby the blade tips are made inaccessible to accidental contact by an operator during normal operation of the mower, and whereby grass and the like is more readily aligned and drawn into the blade by passage of air through the tunnel.

Claim 3

In a rotary mower as recited in claim 1, the radial dimension between the inner radius and outer radius of the shroud being nominally greater than the lengths of human digits.

Claim 4

In a rotary mower as recited in claim 1, wherein said mower has an exhaust chute in the housing and a deck on the housing, the additional improvement comprising: a plate extending downwardly from the underside of the housing to a position just clearing the blade, and extending inwardly and diagonally in opposition to the direction of blade rotation for a portion of the radius of the blade, whereby the blade Is adapted to be cleared of load on passing between the plate and the shroud.

Claim 5

In a rotary mower as recited in claim 3, said plate having a portion extending across the exhaust chute in the plane of blade travel, thereby preventing the blade from ejecting foreign objects in the plane of blade travel.

Claim 6

In a rotary mower as recited in claim 1, each side of the shroud having a recess adapted to expose the blade tips, thereby adapting the mower to produce a full width cut; and a flange extending downward from the shroud and fore-and-aft with respect to the mower outboard of each recess, thereby shielding the recesses, retarding airflow radially inward to said recesses, adapting the mower for producing a sharp boundary on the swath mowed.

Claim 7

In a rotary mower as recited in claim 1, the shroud having notch adapted to receive a portion of a said wheel.

Claim 8

In a rotary mower as recited in claim 1, the shroud being detachable.

Claim 9

In a rotary mower as recited in claim 1, the additional improvement comprising a one-point control for adjusting the height of said tunnel, including a pair of bellcrank-linked axles passing through portions of the housing, said axles having trailing-link offset stub axles, and means for actuating the bell-cranks together, thereby maintaining said shroud parallel with the ground at all times during height adjustment and operation.

Claim 10

In a rotary mower as recited in claim 1, a forward portion of the housing and shroud being detachable, exposing the blade for weed cutting and the like, and a vertical shield for attachment to the housing at the front edge of the position from which the forward portion is detachable.

Claim 11

In a rotary mower as recited in claim 9, the detachable portion of the shroud comprising an arc exceeding a right angle subtended at the blade axis, and having a dovetail portion adapted for securance of the detachable portion.

Claim 12

In a rotary mower as recited in claim 9, the portions of the propeller-type blade overlapping the housing being ground flat and parallel behind the cutting edge as viewed in end elevation, and each blade tip being flat bevelled on the end from the cutting edge back with the greatest depth of the bevel being at the trailing edge, as viewed in plan.

Claim 13

In a rotary mower as recited in claim 9, a one-point control for adjusting the height of said tunnel, including a front axle, a back axle, a bellcrank link between the front and back axles, a trailing-link offset stub axle mounting a wheel at each end of the front and back axles, and means for placing the bellcrank link in various settings, thereby maintaining said shroud parallel with the ground at all said height adjustments.

Claim 14

In a rotary mower as recited in claim 1, the portions of the blade overlapping the shroud being closely proximate the shroud, thereby forming a dynamic air-seal therebetween.

Claim 15

In a rotary mower having a propeller type blade rotating in a horizontal plane in a wheel supported housing open at the bottom, the improvement comprising: a ring-shaped substantially flat shroud substantially co-axial with the blade and forming an annular chamber for the blade with the bottom periphery of the housing, the inner diameter of the shroud being less than the blade length, each side of the shroud having a recess adapted to expose the blade tips, thereby adapting the mower to produce a full width cut, and a flange extending downward from the shroud and fore-and-aft with respect to the mower outboard of each recess, thereby shielding the recesses, retarding airflow radially inward to said recesses and adapting the mower for producing a sharp boundry on the swath mowed, said shroud forming with the ground during mowing a tunnel having a radial extent which is substantially longer than the mower height, whereby the blade tips are made inaccessible to accidental contact by an operator during normal operation of the mower, and whereby grass and the like is more readily aligned and drawn into the blades by passage of air througH the tunnel.

Claim 16

In a rotary mower having a propeller type blade rotating in a horizontal plane in a wheel supported housing open at the bottom, the improvement comprising: a ring-shaped substantially flat shroud substantially co-axial with the blade and forming an annular chamber for the blade with the bottom periphery of the housing, the inner diameter of the shroud being less than the blade length, each side of the shroud having a recess adapted to expose the blade tips, thereby adapting the mower to produce a full width cut, and a flange extending downward from the shroud and fore-and-aft with respect to the mower outboard of each recess, thereby shielding the recesses, retarding airflow radially inward to said recesses and adapting the mower for producing a sharp boundry on the swath mowed, said shroud forming with the ground during mowing a tunnel having a radial extent which is substantially longer than the mower height, whereby the blade tips are made inaccessible to accidental contact by an operator during normal operation of the mower, and whereby grass and the like is more readily aligned and drawn into the blades by passage of air througH the tunnel.