IMPROVEMENTS IN APPARATUS FOR GRINDING LAWN MOWER CUTTERS AND BOTTOM BLADES
Year: 1881

page_text: LETTERS PATENT to Henry Gibbons, of Kennet Iron Works, Hungerford,
in the County of Berks, for an Invention of "IMPROVEMENTS IN APPARATUS
FOR GRINDING LAWN MOWER CUTTERS AND BOTTOM BLADES."
PROVISIONAL SPECIFICATION left by the said Henry Gibbons at the:
Office of the Commissioners of Patents on the 31st May 1881.
HENRY GIBBONS, of Kennet Iron Works, Hungerford, in the County of Berks,"
IMPROVEMENTS IN APPARATUS FOR GRINDING LAWN MOWER CUTTERS AND
BOTTOM BLADES."
This Invention has for its object the production of a cheap and simple machine
for grinding the circular cutters of lawn mowers and also the bottom blades, so that
this operation can be performed by any unskilled person.
The apparatus for grinding the circular cutters consists of a trough or tank, to
each end of which are bolted brackets having bearings in which a shaft works
that carries a grindstone. In the two brackets are guides in which work the
ends of a cross bar that can be moved nearer to or farther from the grindstone
parallel with the axis thereof by screws and handwheels, the said screws passing
through the ends of the cross bar and working in the guides. To the cross bar
are attached two plummer blocks or bearings, one of which is fixed and the other
adjustable, working in a slot in the cross bar so as to increase or diminish the
distance between them. In these bearings are placed the turned ends of the cutter
to be ground. At one end of the cross bar is a bearing in which works a spindle
formed on the inner end to engage with a carrier fixed at one end of the axis of
the cutter. Motion is given to this spindle and from thence to the cutter by means
of two sprocket wheels, one on the spindle and the other on the grindstone shaft,
geared together by an endless chain. The grindstone shaft is screwed the whole
length on one side of the grindstone, and works in a screwed bush in one of the
side bearings on the trough.

page_text: The
In operating with this apparatus for grinding circular cutters the bearings on the
cross bar are first adjusted to a suitable distance to receive the ends of the cutter
to be ground, and the cutter is placed in them. A carrier is then fixed on that end
of the cutter next the spindle in the cross bar. The cross bar with the bearings
and cutter are next set up to the grindstone by the hand wheels and screws.
grindstone shaft is then rotated by a handle, whereby the grindstone is caused
both to revolve and to traverse the length of the cutter owing to the screwed
portion of the shaft being made to work through the screwed bearing as it revolves.
At the same time the chain on the sprocket wheels causes the peripheries of the
cutter and the stone to revolve in opposite directions. Thus both grindstone and
cutter are kept perfectly true. To bring back the grindstone it is necessary to
reverse the motion of the handle.
The apparatus for grinding the bottom blades consists of a bracket bolted to one
corner of the before mentioned trough or tank, and carrying a V guide and slipper.
To the side of the slipper is bolted a slotted angle bracket to which the bottom
blade is fixed by means of covers and bolts. The aforesaid angle bracket can be
raised and lowered on the side of the slipper so as to increase or diminish the angle
of the bottom blade, and so give its cutting edge the required bevil. The grinding
is performed by means of a small emery wheel fixed on a spindle which works in
bearings in a forked lever. Motion is given to the emery wheel from the shaft of
the before mentioned grindstones by means of another pair of sprocket wheels and
endless chain. The lever which carries the emery wheel is hinged at one end,
and at the other is carried on a screwed stud on which it can be raised and
lowered and fixed in position by means of two screwed hand wheels so as to
regulate the position of the emery wheel relatively to the bottom blade, on which
it acts.
For operating with this apparatus for grinding the bottom blades the blade is
fixed to the slotted angle bracket by the covers and bolts as aforesaid, and adjusted
to the proper angle by raising or lowering the angle bracket. The emery wheel
is brought down to the blade and revolved by turning the main shaft. At the
same time the blade is moved backwards and forwards under the emery wheel by
means of the guide and slipper to which it is fastened.
Although I have described the apparatus for grinding the circular cutters and
that for grinding the bottom blades in combination as one machine, yet it will be
evident that each apparatus may be used separately from the other.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Gibbons in the Great Seal Patent Office on the 25th
November 1881.
HENRY GIBBONS, of Kennet Iron Works, Hungerford, in the County of Berks.
"IMPROVEMENTS IN APPARATUS FOR GRINDING LAWN MOWER CUTTERS AND
BOTTOM BLADES."
This Invention has for its object the production of a cheap and simple machine
for grinding the circular cutters of lawn mowers, and also the bottom blades, so
that this operation can be performed by any unskilled person.
The apparatus for grinding the circular cutters consists of a trough or tank, to
each end of which are bolted brackets having bearings in which a shaft works that
carries a grindstone. In the two brackets are guides in which work the ends of a
crossbar that can be moved nearer to or farther from the grindstone parallel with
the axis thereof by screws and hand wheels, the said screws passing through the
ends of the crossbar and working in the guides. To the crossbar are attached two
plummer blocks or bearings, one of which is fixed and the other adjustable,
working in a slot in the crossbar so as to increase or diminish the distance between
them. In these bearings are placed the turned ends of the cutter to be ground.
At one end of the crossbar is a bearing in which works a spindle formed on the
inner end to engage with a carrier fixed at one end of the axis of the cutter.
Motion is given to this spindle and from thence to the cutter by means of two
sprocket wheels, one on the spindle and the other on the grindstone shaft, geared
together by an endless chain. The grindstone shaft is screwed the whole length
on one side of the grindstone, and works in a screwed bush in one of the side
bearings on the trough.
The apparatus for grinding the bottom blades consists of a bracket bolted to one
corner of the before mentioned trough or tank, and carrying a V guide and slipper.
To the side of the slipper is bolted a slotted angle bracket, to which the bottom
blade is fixed by means of covers and bolts. The aforesaid angle bracket can be
raised and lowered on the side of the slipper so as to increase or diminish the
angle of the bottom blade, and so give its cutting edge the required bevil. The
grinding is performed by means of a small emery wheel fixed on a spindle which
works in bearings in a forked lever. Motion is given to the emery wheel from the
shaft of the beforementioned grindstone by means of another pair of sprocket
wheels and endless chain. The lever which carries the emery wheel is hinged at
one end, and at the other is carried on a screwed stud, on which it can be raised
and lowered and fixed in position by means of two screwed hand wheels so as to
regulate the position of the emery wheel relatively to the bottom blade, on which
it acts.
Although I have described the apparatus for grinding the circular cutters and
that for grinding the bottom blades in combination as one machine, yet it will be
evident that each apparatus may be used separately from the other.
In the accompanying Drawings, Fig. 1 is a side elevation of the apparatus
above described; Fig. 2 is a cross section, and Figs. 3 and 4 an end elevation and
plan.
A is a trough or tank, to each end of which are bolted brackets a, a': In
bearings in these brackets works a shaft B, on which is hung a grindstone C. On
the brackets a, a³, are cast guides a², a, in which works a crossbar D. The cross-
bar is moved nearer to or farther from the grindstone by means of the small
screws and hand wheels d, d, passing through the ends of the crossbar D and
working in the guides a², a². To the crossbar D are attached two plummer blocks

page_text: or bearings E, E, one of which is fixed and the other adjustable, working in a slot
in the crossbar D so as to increase or diminish the distance between them. In
these bearings are placed the turned ends of the cutter to be ground. At one end
of the crossbar D is a bearing in which works a spindle F formed on the inner end
to engage with a carrier fixed on one end of the spindle of the lawn mower cutter.
Motion is given to the spindle F, and from thence to the cutter from the main
shaft B by means of the two sprocket wheels G and H, on which works an endless
chain. This chain can be tightened or slackened by means of the small auxiliary
sprocket wheel h, round which it also passes, and which can be raised or lowered
in a slot in the bracket a, and fixed in position where required. The shaft B is
screwed the whole length on one side of the grindstone, and works in a screwed
bush in the bracket al. The sprocket wheel G works on the shaft B by means of
a sliding key, and is prevented from moving from its place by the small angle
piece g working in a groove turned in the boss. The bearings E, E, are fitted on
the outer side with brasses e, e, which are easily removeable, and are held in place
by set screws working through the covers e¹, el. On the inner side the bearings
have V's cut in them. There are several pairs of brasses to suit different sizes of
cutter spindles.
The apparatus for grinding the bottom blades consists of a bracket I bolted to
the side of the tank A. On this bracket is a V guide J in which works a slipper j.
To the side of this slipper is bolted a slotted angle bracket K, to which the bottom
blade is fixed by means of the covers and bolts, as shewn. The aforesaid bracket K
can be raised or lowered on the slipper j so as to increase or diminish the angle of
the bottom blade and so give the cut the required bevil. The grinding is per-
formed by means of a small emery wheel L working on a spindle in bearings in
the forked lever M. Motion is given to the emery wheel from the main shaft by
the two sprocket wheels N and Ō, and by an endless chain, as in the former case.
The lever M is hinged at one end, and at the other works on the screwed stud m.
It can be raised or lowered and fixed in position by means of the two hand
wheels m¹, m³, so as to regulate the depth of cut.
The method of using this apparatus is as follows:-
For grinding a circular cutter the bearings E, E, are first adjusted to a suitable
distance to receive the turned ends of the spindle of the cutter to be ground.
The bearing covers are now removed and the cutter placed with its ends in the V's
at the back of the bearings. Suitable brasses are then placed in the bearings, the
covers replaced, and the set screws tightened up.
A carrier is now screwed on the
end of the cutter spindle next to the spindle F.
The crossbar D with the bearings
and cutter are next set up to the grindstone by the bandwheels and screws d, d.
The shaft B with the grindstone is turned by the handle P and the screwed portion
thereof in working in the bush of the bracket a¹, causes the stone to traverse the
length of the cutter. At the same time the chain on the sprocket wheels G, H,
causes the peripheries of the grindstone and cutter to revolve in opposite directions.
Thus both grindstone and cutter are kept perfectly true. To bring back the
grindstone it is necessary to reverse the motion of the handle P.
For grinding a bottom blade the blade is fixed to the slotted bracket K by the
covers and bolts, and adjusted, to the proper angle by raising or lowering the
bracket K on the slipper j. The emery wheel is brought down to the blade by
adjustment of the lever M, and is caused to revolve by turning the shaft B by the
handle P. At the same time the blade is. moved backwards and forwards under
the emery wheel by means of the guide and slipper to which it is fastened.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,-
First. In apparatus for grinding lawn mower cutters, mounting a grindstone on
shaft having a screw thread, and so arranged that as it is rotated it causes the
grindstone while rotating to traverse along the cutter carried in an adjustable frame
or crossbar in front thereof, substantially as herein described.
Second. The combination with the traversing grindstone referred to in the

page_text: preceding claim, of a shaft or spindle carried by the adjustable frame or transverse
bar, receiving motion from the grindstone shaft by sprocket wheels and pitch
chains, and imparting such motion to the spindle of the cutter by a carrier so as
to cause the surfaces of the grindstone and cutter to revolve in contact in opposite
directions.
Third. The arrangement of the adjustable frame or crossbar with bearings for
the axis of the cutter, and working in guides having adjusting screws, whereby
the crossbar can be set nearer to or farther from the grindstone, substantially as
herein described.
Fourth. The construction of apparatus for grinding lawn mower cutters, com-
bined and operating as herein described with reference to the accompanying
Drawings.
Fifth. In apparatus for grinding bottom blades of lawn mowers, the combi-
nation of an emery wheel mounted on an adjustable lever and rotated by sprocket
wheels and chains with a bracket carrying the bottom blade, and mounted
adjustably on a slipper or slide so as to present the bottom blade at any required
angle to the emery wheel, substantially as herein described.
Sixth. The combined apparatus for grinding the cutters and bottom blades of
lawn mowers arranged and operating as herein described with reference to the
accompanying Drawings.
In witness whereof, I, the said Henry Gibbons, have hereunto set my hand
and seal, this 12th day of November, in the year of our Lord One
thousand eight hundred and eighty one.
11. ĜIDBUND. (LS.)