IMPROVEMENTS IN LAWN MOWERS
Year: 1880

page_text: LETTERS PATENT to John Post Lawrence, of Worship Street, Finsbury, in
the County of Middlesex, for an Invention of "IMPROVEMENTS IN LAWN
MOWERS." A communication from abroad by Coates Walton, of Philadelphia,
in the State of Pennsylvania, United States of America.
"
PROVISIONAL SPECIFICATION left by tho said John Post Lawrence at the
Office of the Commissioners of Patents on the 30th April 1880.
JOHN POST LAWRENCE, of Worship Street, Finsbury, in the County of Middlesex.
IMPROVEMENTS IN LAWN MOWERS." [A communication from abroad by Coates
Walton, of Philadelphia, in the State of Pennsylvania, United States of America.]
The Invention communicated to me consists of improvements in lawn mowers,
and relates to the adjustability of the knives, means for imparting power of the
driving wheels to the rotary cutter in the forward direction, the rotary cutter having
its wipers cast solid with the discs or heads, and with or without the shaft, and
peculiarly constructed ratchet mechanism.
In carrying out the Invention the rotary cutter has its shaft journaled to the
frame, provided with the bed knife or cutter.
To each journal of the shaft is fitted a pinion, which meshes with a spur and
ratchet wheel mounted on the frame, the said wheel being rotated in one direction
by means of a pawl-carrying pinion having an axis on a stud common to the said
wheel. Master wheels which gear with the pawl-carrying wheels are keyed or
otherwise secured to the shafts or axes of the driving wheels, the said shafts or
axes being mounted on caps or boxes secured at one end to the frame by bolts or
screws, and at the other end by the studs which pass through the caps or boxes
and are held by nuts or other means.
The spur and ratchet wheel is constructed with teeth or shoulders at its periphery
and teeth or shoulders at its centre or hub, and in the space between the two series
of shoulders the pawl of the spur wheel or pinion has its play; the said pawl
consisting of a sliding tooth or pieco fitted between guides projecting from the inner
face of an arm or plate formed with or secured to the pinion.
When the mower is pushed or drawn forward the power of the wheels is imparted

page_text: to the master wheels and pinions, and each pawl engages with one of the shoulders
of either series, so that rotation is imparted to the pinions and consequently to the
cutter.
When a pawl is above or uppermost it drops and engages with one of the central
or inner series of shoulders, and when it is below it drops and engages with the
peripheral series of shoulders, so that the engagement of the pawls with the
shoulders is reliablo at all times, and owing to the number of shoulders the pawls
quickly engage with either of them and always with those first within reach.
When the mower is run back the pawls ride freely over the shoulders, whereby
the rotary cutter is at rest or remains stationary.
The rotary cutter consists of spiral or other shaped blades bolted, riveted, or
otherwise connected to the wipers which are integral or cast with heads or discs.
The shaft is passed centrally through the said heads or discs, which may be cast
around the shaft or otherwise secured to it, and it will be seen that by the provision
of casting or forming the wipers and heads or discs in one piece, the cutter may
be made light and strong, produced with greater facility, and reduced in expense.
The forward ends of the side pieces of the frame are provided with a series of
openings arranged in circular order from the studs as centres. The caps or boxes
are fitted on the said studs, as herein before described, and the bolts or screws may
be passed through either of the openings. By this provision the frame may be
raised and lowered, and the cutters or knives accordingly adjusted to the ground or
extent of cut.
The ratchet mechanism consists of a laterally shifting or moveablo whoel fitted
loosely on the cutter shaft of the mower, and having ratchet teeth alternating on
opposite sides. A pin or pawl fixed to the said shaft circumscribes each side of the
wheel, and is so disposed that on the forward motion of the mower either pin or
pawl is engaged by the teeth which are nearest to or come first in contact with
one of the pins or pawls, consequently the shaft is rotated and the cutter quickly
set in motion. When the mower is run back the teeth ride freely over the pins
or pawls, and consequently loosely on the shaft, thus rendering the rotary cutter
inactive.
A wheel moves freely on the shaft, but one side being provided with ratchet
teeth; a pawl is fitted in a slot in the shaft so that its ends project, and the centro
of the pawl is pivotted to the shaft, whereby as the pawl rocks or swings one of
its ends rises or advances as it rides over a tooth, and the opposite end lowers or
returns against the untoothed or flat portion of the wheel.
It is evident that when the wheel is rotated in one direction one of the ratchet
teeth engages with the end of the pawl that is nearest to the said tooth, whereby
the shaft is rotated and the rotary cutter operated. The rotation of the wheel in the
opposite direction causes the ratchet teeth to ride freely over both ends of the pawl
alternately without rotating the shaft and cutter.
By the improvements in ratchet mechanisni, owing to the multiplicity of ratchet
teeth, the engagement of the pawl with a tooth is immediately occasioned.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Post Lawrence in the Great Seal Patent Office on the
26th October 1880.
JOHN POST LAWRENCE, of Worship Street, Finsbury, in the County of Middlesex.
"IMPROVEMENTS IN LAWN MOWERS." A communication from abroad by Coates
Walton, of Philadelphia, in the State of Pennsylvania, United States of America.
The Invention communicated to me consists of improvements in lawn mowers.
First. The adjustability of the knives.
Second. Means for imparting the power of the driving wheels to the rotary
cutter in the forward direction.
Third. The rotary cutter having its wipers cast solid with the discs or heads,
and with or without the shaft.
Fourth. Peculiarly constructed ratchet mechanism.
But to make the Invention communicated to me better understood I will
proceed to describe the same by reference to the accompanying Drawing, in which
Figure 1 shews a plan of the mower; Figure 2, an end view of same; and Figure 3,
a section on line x, x, of Figure 2; Figures 4, 5, 6, and 7, detached detail views of
some of the parts. Similar letters in all the Figures represent similar parts.
A represents the frame of the mower; B, the rotary cutter having its shaft B'
journalled to the said frame; C is the bed knife or cutter.
To cach journal of the shaft B' is fitted a pinion D which meshes with a spur
and ratchet wheel E mounted on the frame A, the said wheel E being rotated in
one direction by means of a pawl carrying pinion F, having an axis on the stud a
common to the wheel E; G represents master wheels which gear with the pawl
carrying wheels F, and are keyed or otherwise secured to the shafts or axes of the
driving wheels H, the said shafts or axes being mounted on caps or boxes J secured
at one end to the frame A by bolts or screws J', and at the other end by the
studs a, which pass through the caps or boxes and are held by nuts or other
suitable means.
The spur and ratchet wheel E is constructed with teeth or shoulders b at its
periphery, and teeth or shoulders 6¹ at its centre or hub, and in the space between
the two series of shoulders the pawl F' of the spur wheel or pinion F has its play,
the said pawl consisting of a sliding tooth or piece fitted between guides projecting
from the inner face of an arm or plate c formed with or secured to the pinion F.
When the mower is pushed or drawn forward the power of the wheels is
imparted to the master wheels G and pinions F, and each pawl F1 engages with one
of the shoulders of either series b, b', so that rotation is imparted to the pinions D,
and consequently to the cutter B.
It will be seen that when a pawl is above or uppermost it drops and engages
with one of the central or inner series b¹ of shoulders, and when it is below it
drops and engages with the peripheral series b of shoulders, so that the engagement
of the pawls with the shoulders is reliable at all times, and owing to the number
of shoulders the pawls quickly engage with either of them, and always with those
first within reach.
When the mower is run back the pawls ride freely over the shoulders, whereby
the rotary cutter is at rest or remains stationary.
The rotary cutter consists of spiral or other shaped blades bolted, rivetted, or
otherwise connected to the wipers K, which are integral or cast with heads or
discs K. The shaft B' is passed centrally through the said heads or discs, which
nay be cast around the shaft or otherwise secured to it, and it will be seen that
by the provision of casting or forming the wipers and heads or discs in one piece
he cutter may be made light and strong, produced with greater facility, and reduced
n expense.
The forward ends of tho side pieces of the frame A are provided with a series of

page_text: The caps or
openings & arranged in circular order from the studs a as centres.
boxes J are fitted on the said studs a, as herein before described, and the bolts or
By this provision
screws J¹ may be passed through either of the openings d.
the frame A may be raised and lowered, and the cutters or knives accordingly
adjusted to the ground or extent of cut.
The ratchet mechanism shown in Figures 4 and 5 consists of a laterally shifting
or movable wheel L fitted loosely on the cutter shaft of the mower, and having
ratchet teeth e, el, alternating on opposite sides. A pin or pawl L' fixed to the
said shaft circumscribes each side of the wheel L, and is so disposed that on the
forward motion of the mower either pin or pawl L' is engaged by the teeth e or e¹
which are nearest to or come first in contact with one of the pins or pawls, conse-
When the
quently the shaft is rotated and the cutter quickly set in motion.
mower is run back the teeth e, c', ride freely over the pins or pawls, and consequently
loosely on the shaft, thus rendering the rotary cutter inactive.
In Figures 6 and 7 the wheel L" moves freely on the shaft, but one sido being
provided with ratchet teeth cl The pawl L is fitted in a slot in the shaft so
that its ends project, and the centre of the pawl is pivotted to the shaft, whereby,
as the pawl rocks or swings, one of its ends rises or advances as it rides over a
tooth e, and the opposite end lowers or returns against the untoothed or flat
portion of the wheel.
It is evident that when the wheel L" is rotated in one direction one of the
ratchet teeth engages with the end of the pawl L that is nearest to the said
The rotation
tooth, whereby the shaft is rotated and the rotary cutter operated.
of the wheel L" in the opposite direction causes the ratchet teeth to ride freely
over both ends of the pawl alternately without rotating the shaft and cutter.
By the improvements in ratchet mechanism, owing to the multiplicity of ratchot
teeth, the engagement of the pawl with a tooth is immediately occasioned.
Having thus described the nature of the Invention communicated to me and the
best means with which I am acquainted for carrying the same into effect, I wish it
to be understood that what is claimed and intended to be protected by the herein-
before in part recited Letters Patent is,―
Firstly. The adjustment of the knives by means of the openings d in the
frame A which receive bolts or screws passed through the caps or boxes J, sub-
stantially as and for the purpose set forth.
Secondly. The adjusting openings & in the frame A radially arranged from the
studs a as centres, the disconnectible or movable caps or boxes J being fitted on
said studs.
Thirdly. The ratchet wheel having a series of both peripheral and central ratchet
teeth or shoulders, and operating in connection with a suitable pawl adapted to
engage with the teeth of either series.
Fourthly. The rotary cutter having its wipers and beads or discs integral, solid
or cast in one.
Fifthly. A shaft having a loosely fitted laterally shiftable ratchet wheel, and
fixed pins or pawls circumscribing the sides of the wheel, forming an improved
ratchet mechanism.
Sixthly. A shaft having a loosely fitted ratchet wheel and a rocking or swinging
pawl operating therewith as an improved ratchet mechanism.
In witness whereof, I, the said John Post Lawrence, have hereto set my
hand and seal, this Second day of September, in the year, of our Lord
One thousand eight hundred and eighty.
JOHN P LAWRENCE