Improvements in Lawn Mowers
Year: 1889

page_text: [Communicated from abroad by HENRY GREGORY DUNLOP CARR, of Brooklyn, in
the State of New York, United States of America, Merchant.]
Improvements in Lawn Mowers,
1 PHILIP ARTHUR NEWTON of the Office for Patents, 6 Bream's Buildings, Chancery
Lane, in the County of Middlesex, Patent Agent, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
This invention relates generally to improvements in the construction and mode of
adjustment of difforent parts of lawn mowers of that class in which are employed
rotary heads carrying spiral cutter blades acting in conjunction with a fixed cutter
blade, said rotary heads and blades deriving their rotary motion through suitable
connections from the ground wheels of the mower.
The improvements constituting the present invention consist; first, of a main
framework consisting of a single casting in which are included the side portions of
the frame, and also the tie-bars or cross portions used for giving strength and rigidity
to the mower; second, of rotary cutter heads having projections to which are
detachably secured the spiral cutting blades with which they are provided; which
blades may be removed, when desired, for the purpose of renewal or repair; third, of
improved operating connections between the rotary cutter heads and the ground
wheels, whereby the operation of said rotary heads and their blades is secured, with
less liability of breakage or derangement of parts than in former constructions ;
fourth, of a fixed cutter blade of curved form secured to a correspondingly shaped
portion of the frame, and capable of easy and ready adjustment relatively to the spiral
blades; and fifth, of vertically arranged rack bars in which the ground roller is
journalled, and upon which tho frame of the machine may be raised and lowered to the
required extent, to produce any desired height of cut, or for any desired character of
field work.
The various improvements thus briofly outlined will be most readily understood

page_text: from a detailed description and an illustration of an organization in which they are
embodied. Further preliminary description will, therefore, be dispensed with, and a
somewhat detailed description given of such an organization, reference being had, in
such description, to the accompanying drawings, in which
Fig. 1 is a plan view of a lawn mower constructed according to the invention.
Fig. 2 is a longitudinal sectional elevation, taken on the line 2, 2 of Fig. 1.
Fig. 3 is a vertical section on the line 3 of Fig. 2.
Fig. 4 is a longitudinal section on the line 4 of Figs. 1 and 5; and
Fig. 5 is a horizontal section on the line 5 of Fig. 4.
Referring to said Drawings, it will be seen that A A represent the ground wheels
of the mower; B B the rotary cutter heads; C the ground roller; D the handle,
and E E curved rods by which said handle is connected to the framework of the
mower.
The frame proper of the machine is (as will be seen by reference to Figs. 1 and 2)
made in a single casting, which includes the sides H of the frame, and also front and
rear tie-bars 5, 4.
Before entering upon a detailed description of the different parts of the mower, it
will first bo remarked that as the parts upon each side of the mower are exact
duplicates as to construction and mode of operation of those upon the other side, a
description of those upon one side only will suffice for a ready understanding of the
invention.
Referring now particularly to Figs. 1 and 2, the construction of the frame therein
illustrated will be described. As-shown, each side H of the frame forms at its front
a plate 2, which is of semi circular shape, and fits within the flange 6 of the ground
wheel A, so as to form a casing for the lower half of said wheel upon its inner
side. The plate 2 is also provided with a flanged upper edge 7, in which is formed
the lower halves of the boxes for the journals 8, 9 of the ground wheel A and the
cutter head B. The rear portion 3 of each sido H is of the form shown, and is
supported in position by the rack bar in which the ground roller C is journalled,
as hereinafter described. The rearwardly extending portions 3 of the sides of
the frame are connected by a transverse bar 4, which forms a rear tie bar, and carries
the fixed cutter of the mower. The plates 2 of the sides are connected by a front tio-
bar 5, which is an extension of the flanges 7, and extends transversely across the
machine, as shown in Fig. 1.
The construction and mode of operation of the ground wheel A and the rotary
cutter head B, and their operating connections, will now be described. As before
remarked, the ground wheel A has formed upon its periphery an inwardly extending
flange 6, upon a shoulder in which is seated the plate 2 forming a casing for the
lower half of said wheel. The upper half of said wheel also receives a similarly
shaped plate 10, seated within its Hange, and completing the casing of said wheel,
which plate is secured to the sides of the frame, and forms the upper halves of the
boxes for the journals 8. 9. The flange 6 has cut upon its inner periphery gear
teeth 11 engaging with a pinion 12. The shaft 13 of the pinion 12 extends through,
and turns freely in a longitudinal opening in the journal 9 of the head B (as shown
in Figures 2 and 5). The rotary cutter head Cis provided, upon its inner side, with
a circular flange 15, upon which are cast, in the manner shown, a series of spiral
projections 16, to which are detachably secured (as best shown in Fig. 1) spiral cutter
blades 17. The shaft 13 of the pinion 12 has connected to its inner end, by means of
a key 18, a circular plate 19, seated loosely on a shoulder formed upon the inner
surface of the flange 15 of the cutter head, and resting against a circular projection 20
formed on the cutter head, and enclosed within said flange, as shown in Fig. 5. When
the wheel A has been put in motion, movement will be imparted by it to the pinion 12,
and through the shaft 13, to the plate 19. For the purpose of having this movement
of the plate 19 communicated to the rotary cutter head B and its blades 17, the
internal periphery of the flange 15, and the periphery of the circular projection 20 of
said rotary head, are each provided with a series of ratchet teeth 21 (see Fig. 4),
which, when the ground wheel A and pinion 12 are revolved in a forward direction,

page_text: will be engaged by a pawl 22 pivotted to the plate 19, as shown in Fig. 5. said pawl,
during the backward rotation of said ground wheel and pinion, passing idly over the
teeth 21, and during their forward rotation engaging with a tooth 21 upon tho
flange 15, or projection 20 (whichever tooth is nearest at the time of movement),
and causing the rotary cutter head and its blades to rotate also in a forward direction.
The construction which has been described provides an exceedingly simple and
économical form of rotary cutter, the two heads B being exact duplicates, and
being cast entirely independent of each other. The spiral blades 17, when fastened
to the arms 16, so as to connect the heads, make an exceedingly rigid and light
cutter. The blades 17 being removable, it is impossible to renew any one blade
which may become worn without renewing the entire cutter.
In the constructions heretoforo common, the pinion 12, which engaged with the
internal gear of the ground wheel, has been loosely mounted upon its shaft, and the
pawl and ratchet mechanisin for communicating the motion of the pinion to the rotary
cutter upon the forward movement of the mower, has been located in a recess formed
in said pinion. As it is necessary, in order to give the required speed to the rotary
cutter, that the pinion 12 should be quite small, it followed that the pawl and ratchet
mechanism for connecting the pinion to its shaft was correspondingly reduced in size,
50 as to be of minimum strength, and being located close to the axis of the pinion,
was subjected to such strain that it sometimes became broken. By the present con-
struction, however, the pawl and ratchet mechanism being located in the heads of the
cutter, can readily be made of much greater size and strength, and can be located at
a greater distance from the axis of the cutter, thereby subjecting it to less strain.
The construction and arrangement of the fixed blade, and its method of adjustment
upon the transverse bar 4, will now be described. The bar 4, as before remarked,
extends transversely across the machine between the rear portions 3, 3 of the
frame (see Fig. 1). The cutter blade is of curved form in cross section (see Figs. 2
and 4), and is secured to the underside of the transverse bar 4, which is convex in
form, to accommodate itself to the shape of the cutter blade, by means of screw
studs 23 passing through transverse slots 24 in the cutter blade F. When it is
desired to adjust the cutter blade Fat any desired distance from the rotary spiral
blades 17, the screw studs 23 will be loosened, and the cutter blade moved forward or
backward to the proper extent, and then secured again in its adjusted. position by
tightening said screw studs. It will be noticed that the advance of the cutter blade
upon the bar 4, causes it also to rise, and its retraction upon said bar causes it to fall,
this being due to the curvilinear form of said cutter blade and transverse bar 4. By
thus constructing the cutter blade, I am enabled to secure, by one adjustment, that
which has only beon accomplished, in prior constructions, by the employment of two
or more adjustments, viz., the advance and retraction of said cutter blado, and its
proper degree of elevation relatively to the spiral cutter blades.
The rear portions 3, 3, of the frame, are supported in proper position above the
ground upon vertical rack bars G G, one upon each side of the mower, in the lower
ends of which are journalled the ends of the ground roller C (see Figs. 2 and 3).
These bars are formed, upon their inner surfaces, with teeth 25, into which mosh
teeth 26 upon the respective adjacent surfaces of the rear portions 3, 3 of the frame.
The vertical plates G are each also provided with a central slot 27, in which moves a
screw stud 28, secured to the rear portion 3. When it is desired to adjust the mower
for the production of any particular height of cut, or for any particular piece of field
work, the screw stud 28 will be loosened, and the rear portion 3 of the frame raised
or lowered, as the case may be, to the required position, and its tooth 26 brought
into engagement with the teeth 25 of the bar G, and be locked in its adjusted
position by tightening the screw stud 28.
It is obvious that many of the parts above described may be used independently of
the others, or in combination with the whole, or less than the whole, of said parts. I
do not therefore limit myself to their use in combination, as shown and described, but
claim broadly the use of many of them separately or together in machines differing in
construction from that shown and described.

page_text: Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, as communicated to me
by my Foreign Correspondent, I declare that what I claim is :-
1. In a lawn mower, a frame consisting of a single casting comprising sides H
forming plates 2,2, for partly enclosing the driving gearing, and forming one member
of the boxes for the journals of the ground wheels and rotary cutter, and also rear-
ward extensions 3, 3 for supporting the ground roll, the tie-bar 5 connecting the
plates 2, 2, and the tie-bar + connecting the extensions 3, and supporting the stationary
cutter, substantially as described.
2. The construction and organization of the rotary and fixed cutters of a lawn
mower, substantially as herein shown and described.
3. The combination with the ground wheels and rotary cutter heads, of the
pinions 12, engaging with internal gears upon the ground wheels, and fixed upon
the shafts 13, which pass through the journals of the cutter beads, and terminate
upon the inside thereof; plates 19 fixed upon the said shafts 13, pawls pivotted
upon said plates 19, and internal and external ratchot teeth 21, formed upon the
cutter heads, to engage with said pawls, substantially as described.
4. The fixed cutter blade F, adjustable to and from the rotary cutter in a curved
path, substantially as described.
5. The means for adjusting the height of the fixed cutter substantially as herein
described.
Dated this 19th day of March 1889.