1950 – Fairbanks-Morse “Grass Finder” Rotary Power Lawn Mower – (American)

The gasoline-powered Fairbanks-Morse Grass Finder has no cord. Run it around the outside of your lawn once to give it the feel of things and from then on it runs itself, feeling for the high uncut grass with its left hand, as it were, and following along the edge of the previous cut until it has spiraled into the center. At this point it runs in circles until someone comes.


Source: Wilwaukee Sentinel, 3 May 1953.

Grass Grows, Mower Mows –Which Lets You Doze

Save time and energy used in cutting the lawn, week after week after week, and you can keep those flower beds weeded, the car polished, the thousand and one around-the-house chores under control or you can just relax, play bridge, doze.
 It can now he done with the new "Grass Finder" lawn mower that cuts grass by itself with out so much as a finger of guidance. Powered by a gasoline engine, this automatic mower has feelers at the front that keep the machine operating through the uncut grass until the last blade has been cut and mulched.
Fairbanks, Morse & Co. has added this automatic model to its broad line of electric and gasoline-powered mowers to sell for under $300.00.
Any shape or size of lawn can be cut with this sensational new mower. The operator cuts a single strip around the area to be mowed, then sets the mower in automatic operation by pushing up the handle to a vertical position and lets it go to work. From then on the machine needs no touch from human hands.
Mechanical feelers guide the "Grass Finder" along the long grass line, around curves and corners, as it works in a clockwise direction toward the center of the plot.
The automatic "nose" of this new mower is a mechanical feeler device on the left front side which contacts the tall grass. This contact releases a brake and causes the mower to straighten out until the feeler reaches cut grass whereupon the mower again weaves to the right.
The machine is simple in design, wholly mechanical and sturdy. An extra dividend is that as grass is cut it is thrown to the right and the snips mulched and remulched so that no raking is necessary.
The mower cuts an 18-in. swath and can he used on grass 2 1/2 to 7 inches high. Cutting height can he adjusted from 1 1/23 to 2 2/3 inches. The machine can cut square corners, avoid flower beds, function automatically on grades up to 20 per cent. It makes lawn tending a pleasure.


Source: Kiplinger's Personal Finance, Apr 1954

The gasoline-powered Fairbanks-Morse Grass Finder has no cord. Run it around the outside of your lawn once to give it the feel of things and from then on it runs itself, feeling for the high uncut grass with its left hand, as it were, and following along the edge of the previous cut until it has spiraled into the center. At this point it runs in circles until someone comes.


See other early remote-controlled and robotic lawn mowers here.