Improvements in or relating to Lawn Mowers.
Year: 1899

page_text: Date of Application, 12th Aug., 1899
Complete Specification Left, 12th May, 1900-Accepted, 14th July, 1900
Improvements in or relating to Lawn Mowers.
I, THOMAS COLDWELL, of Newburgh, New York, United States of America,
Lawn Mower Manufacturer, do hereby declare the nature of this invention
to be as follows:-
This invention has for object three distinct improvements in or relating to
lawn mowers:-
1. Ball bearing adjustments from one side of the frame only and having a
cushioned resilient bearing to resist end on thrust due to motion of the spirally
arranged cutting blades.
2. Making the fixed knife in one with the knife bar by a casting process, so
that I obtain rigidity of the position without interfering with the springiness or
temper of the knife when in use.
3. Making the grass box of canvas suspended from a top frame, and arranging
a weight or strainer bar to the bottom front end of the box to prevent the cut
grass being shot out of the box when a hillock or obstacle is struck.
According to the first improvement, I prepare both ends of blades carrying axle
with inclined or cone surfaces for the balls or spheres to ride against, one end is
short for the adjustment screw and the other is long and projects sufficiently to
carry the gear wheel. Both cone surfaces are in caps which have corresponding
internal cones or inclines, the backs of both caps being free.
Between the back of one cap and the frame of the machine I arrange a soft
india rubber pad or airtight balls or rings for cushioning to resist the thrust of
the spiral blades while cutting, the other or stump end being within the back of
its cap for centering purposes and to enable the adjustment by a screw from
that side of the machine only. The stump end cap may also be cushioned such
as by a stout rubber washer and an intervening plate for the screw to bear
against. By the use of the rubber cushioning the noise while the machine is at
work is so reduced as to be unnoticeable.
The second improvement is in the manufacture of the stationary knife which
is usually formed of two parts, a very strong cast metal back and a thin sheet
metal blade which is attached to the back by means of screws.
This is open to
serious objection as the blade is clamped tightly only adjacent to the screws,
and the edge of the blade does not have a uniform degree of elasticity which is
necessary to the perfect operation of lawn mower knives.
By this second improvement, I cast a dummy bar beneath the outer edge of the
steel blade connected with the back by a series of webs made by the passages which
conduct the hot metal to the mould for the dummy bar and thus the entire
width of the blade is exposed to the heating action of the molten metal which
causes it to expand uniformly throughout. When, the casting cools the knife will
be straight and it is only necessary to break the webs to detach the dummy bar
leaving the knife with one edge embedded in the solid cast metal back. To
effect this blade to a cast, I place the blade in a suitable mould casting the back

page_text: along and upon one edge of the blade thereby heating this edge and causing
it to expand, simultaneously heating the front or cutting edge throughout its
length to cause it to expand at the same rate as the back edge and allowing all
portions of the blade to cool simultaneously with the cast back.
The third improvement consists in making the front grass box of canvas of any
desired pattern (plain or fancy) and sewing or rivetting to an upper skeleton
frame, the two ends of which are secured to the frame of the machine behind the
drum and blades according to the make of the machine and with the box suspended,
the lower fore end of the box being weighted so that it is kept down and yet
yield when it meets an obstruction and recovers itself without risk of the cut
grass being shot out on to the machine.
13
11.
1
J
1000
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said Thomas Coldwell.
I, THOMAS COLDWELL, of Newburgh, New York, United States of America,
Lawn Mower Manufacturer, 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 has for object three distinct improvements in or relating to
lawn mowers:-
1. Ball bearing adjustments from one side of the frame only and having a
cushioned resilient bearing to resist end on thrust due to motion of the spirally
arranged cutting blades.
2. Making the fixed knife in one with the knife bar by a casting process, so
that I obtain rigidity of the position without interfering with the springiness or
temper of the knife when in use.
3. Making the grass box of canvas suspended from a top frame, and arranging
a weight or strainer bar to the bottom front end of the box to prevent the cut
grass being shot out of the box when a hillock or obstacle is struck.
My invention will be understood from the following description aided by the
accompanying drawings in which Figure 1 is an elevation of cutter blades and
axle, with the bearings in section.
Figure 2 is section of a mould with the dummy bar and webs cast on to the
cutter bar.
Figure 3 is a section of a dummy bar and knife complete.
Figure 4 is a side elevation of a lawn mower, showing the grass box.
According to the first improvement, such as I show at Figure 1 I prepare both
ends of blades carrying axle. A with inclined or cone surfaces B, B', for the
halls or spheres C to ride against, one end A' is short for the adjustment screw D,
and the other A3 is long and projects sufficiently to carry the gear wheel.
Both cone surfaces B are in caps E, E', which with the cone surfaces carry the
balls C, the backs of both caps being free.
Between the back of one cap E and the frame F of the machine, I arrange a
soft india rubber pad G or airtight balls or rings for cushioning to resist the
thrust of the spiral blades H while cutting, the other or stump end A being
within the back of its cap for centering purposes and to enable the adjustment by
a screw D from that side of the machine only. The stump end cap E¹ may also

page_text: be cushioned such as by a stout rubber washer and an intervening plate for the
screw D to bear against.
By the use of the rubber cushioning the noise while the machine is at work is
so reduced as to be unnoticeable.
The second improvement is in the manufacture of the stationary knife which
is usually formed of two parts, a very strong cast metal back, and a thin sheet
metal blade which is attached to the back by means of screws. This is open to
various objection as the blade is clamped tightly only adjacent to the screws, and
the edge of the blade does not have a uniform degree of elasticity which is
necessary to the perfect operation of lawn mower knives.
By this second improvement, as at Figures 2 and 3, I cast a dummy bar I
beneath the outer edge of the steel blade J connected with the back by a series
of webs K made by the passages which conduct the hot metal to the mould for
the dummy bar I and thus the entire width of the blade J is exposed to the heating
action of the molten metal which causes it to expand uniformly throughout.
When the casting cools, the knife J will be straight and it is only necessary
to break the webs K to detach the dummy bar I leaving the knife with one edge
embedded in the solid cast metal back Ľ.
To effect this I place the blade in a suitable mould M casting the back L along
and upon one edge of the blade J thereby heating this edge and causing it to
expand, simultaneously heating the front or cutting edge throughout its length
to cause it to expand at the same rate as the back edge and allowing all portions
of the blade to cool simultaneously with the cast back.
The third improvement, as at Figure 4, consists in making the grass box N of
canvas of any desired pattern (plain or fancy) and sewing or rivetting to an
upper and lower skeleton frame P, the two ends Q of which are jointed to the
frame of the machine behind the drum and blades according to the make of the
machine and with the box N suspended by links R, the lower free end of the
box being weighted, as at S, so that it is kept down and yet yield when it meets
an obstruction and recovers itself without risk of the cut grass being shot out
on to the machine.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
The improvements in or relating to lawn mowers consisting of:-
1. The particular construction of bearings whereby the same may be adjusted
from one side of a machine, and providing such bearings with a cushion or
cushions to resist end on thrust, substantially as set forth.
2. Making the stationary knife with a strong metal back cast upon same in the
manner herein set forth for imparting to the blade a uniform degree of elasticity,
as described.
3. Constructing grass boxes from canvas or like material secured at top and
bottom to a jointed skeleton framing, as set forth.
TUL 10t 1
30
1000
R. CORE GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said T. Coldwell.
R. CORE GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said T. Coldwell.