Improvements in Machines for Grinding Mower Knives.
Year: 1886

page_text: Improvements in Machines for Grinding Mower Knives.
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I, RUFUS DUTTON, of Yonkers, in the county of Westchester, and State of
New York, United States of America, Manufacturer, do hereby declare the nature
of my invention for "IMPROVEMENTS IN MACHINES FOR GRINDING MOWER
KNIVES," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
Very many machines in this line have been heretofore devised and 'patented,
and for the better understanding of the character of my invention, I will first
state that said prior machines may be fairly divided into Four general classes,
namely―
First those which embody longitudinally reciprocating hones of various kinds
and form.
Second-those which embody wheels having angular or beveled grinding surfaces
at their peripheries, and are either adapted to operate simultaneously upon the
coincident edges of the two adjoining knife sections, as when the wheels are wide;
and have a double bevel, or upon one edge at a time, as when said doubled
beveled wheels are narrow, or when they are wide and are beveled from one
edge only.
Third those which embody grinding wheels having peripheries which are not
used for this service, but have either flat or beveled sides, which afford the grinding
surface for contact with a mower knife; and
Fourth such as embody grinding wheels having flat or rectangular faced
peripheries which afford the requisite grinding surface.
These four classes of machines include only such as have been specially organized.
for grinding mower, knives, and do not include another large variety of patented.
devices which are in fact special attachments for use with ordinary grindstones,
and upon their regular frames, but as such grindstones have usually flat faced
peripheries, they with said attachments, approximate more or less closely to. the
last named variety of mower knife grinding machines, and it is to this particular
class, that my machines belong, when embodying my complete invention.

page_text: Nearly all of the prior machines thus generally referred to, have means of some
kind for holding a mower knife during the grinding operation, and said grindstone
attachments are solely for the purpose of facilitating the holding and handling of
the knife by the grinder.
It is well known that the grinding of mower knives upon the peripheries of
ordinary grindstones, as a rule, soou unfits the latter for other service; also that
the variable movement of such grindstones, as well as their liability to have nicked
edges or soft spots, renders special machines for this service very desirable. It is
also well-known that a grinding wheel having a beveled periphery of special
angular dimensions for working simultaneously on two adjacent knife edges, soon
looses its special form, and operates irregularly, because the angular centre is-soon-
worn away to a rounded rib, and the same is partly true of such grinding wheels
as have a beveled periphery adapted to operate only on one edge of a knife section
at a time, and necessitating the successive working of all the parallel knife edges,
and then reversing the position of the knife both lengthwise and widthwise, for
successively working the alternate remaining edges. The importance of uniformity
in grinding mower knives is not only apparent with reference to satisfactory field
service, but also in the matter of economy in the knives themselves, and I have
proceeded in the development of my machines upon the theory that a grinding
wheel with a constantly varying face-contour, cannot be relied upon to operate
with uniformity upon a mower knife, and one object of my invention is to provide
for a substantially uniform rectangular grinding face, regardless of the inevitable
gradual reduction of the diameter of the grinding wheel. To this end I have,
as I believe, for the first time specially proportioned the width of the periphery
of a flat rectangular faced grinding wheel to the width of a mower knife section,
so that in grinding one edge of a knife section the point of its contact with the
grinding surface will traverse from one edge of the face of the stone, nearly to the
opposite edge thereof, and then in grinding the next adjacent edge of the next
knife section, (and from the bottom of the V to the tip, in both cases) the grinding
surface will be oppositely traversed, thus not only subjecting the entire face to
uniformn abrasion, but also maintaining sufficiently full grinding edges on the
wheel for working well into the V-junction of any two knife sections. In other
words, for obtaining the best results, I employ a grinding wheel having a flat
rectangular face at its periphery, a little wider than one-half the width of a knife
section, and therefor I am enabled to always grind each portion of a knife edge,
upon a corresponding portion of the grinding surface, and to alternately subject
the grinding wheel to abrasive action, first from one edge inward, and then from
the opposite edge inward, and each time, to subject the intervening portions' of the
periphery to uniform service, even when one knife edge chances to be nicked inore
than another, because such nicks are as liable to occur in one knife edge as another,
and therefore the extra abrasive effect on the face of the grinding wheel in working
out such nicks, will be substantially equalized.
1
Flat rectangular faced wheels or stones in mower knife grinding machines, as
heretofore organized, have been combined with knife. holding devices so that the
grinding surface of the wheels either operated at right angles to the edge of each'
knife. section, and crosswise of its beveled edge, or substantially parallel with said
edge, and its bevel. I desire that my wheel shall have its grinding surface operate
angularly to the knife edge so that the abrasive lines on the latter will be diagonal
to the edge. This desirable arrangement of the abrasive lines is, however, a result
of the use of some machines having beveled or!angular faced grinding/wheels, and
also the result of skillful grinding by hand on a specially selected grindstone, and
also the result of skillful manipulation of the knife, while partially.theld by soine
one of the hereinbefore mentioned grindstone attachments, buti Ibelieve I am the
first to devise a machine embodying a grinding wheel having a flat rectangular
periphery for its grinding surface; and means for holding the knife, so that the
latter will require no manipulation whatever during the grinding operation; and

page_text: which will develop abrasive lines angularly to each knife edge, and which will
always progressively grind each portion of each edge upon a corresponding portion.
of the grinding surface, and thus secure uniform wear of the wheel, and enable
a person of ordinary intelligence to grind a mower knife as evenly and more
economically, than if ground by the most skillful grinder, with a perfect grindstone,
whether used with or without any of the before mentioned attachments by which
the grinding operation may be more conveniently performed than when the knife
is held solely in the hands of the operator.. In such prior machines as embody
what are known as flat faced grinding wheels (in that they have grinding faces
rectangular to the sides of the wheel or stone,) the wheels have been so mounted
that they could be operated in various inclined positions, for grinding the bevels
of knife sections, and so as to be moved along each edge from its base or junction,
to its tip, and, in all specially organized machines of this particular class, the
pressure between the knife and wheel is applied directly by the operator in forcing
the wheel toward the knife held in a non yielding clamp. Grindstone attachments
have heretofore embodied yielding or spring backed clamps, which in all instances
have been so constructed as to not only require the manipulation obviously
necessary for adjusting a mower knife in the clamp, but also actual manipulation
of said knife and clamp during the grinding operation, and although I employ
a spring backed clamp in machines embodying my complete invention, said clamp
not only rigidly holds a knife, but presents it with proper pressure at either edge
of the grinding wheel face, and in such exactly proper position, as to require no
manipulation of the knife or the clamp during the grinding operation; and unlike
any other contrivance known to me for grinding mower knives said clamp is
enabled to consecutively present the two coincident edges of any two successive
knife sections, to the opposite edges of the flat grinding face without readjustment
of the knife in said clamp.
In many of said prior machines, and attachments, the clamps have been mounted
upon frames, and coupled to the grinding wheel frame so as to provide for certain
swiveling movements, of one of said frames with relation to the other, and in
every case the swinging movement of the clamp frame and of the clamp thereon,
has been around certain axial points or centres, which are wholly outside of, and
more or less remote from the grinding wheel. Otherwise stated, said prior machines
and attachments have embodied pivotal centres for their clamps and clamp frames,
which in each case, have been located somewhere at the rear of the clamp, and in
no case has the clamp frame and wheel frame, been coupled by pivots, or swiveled
with reference to centres, located in front of the clamp and coincident with the
grinding face. Machines embodying the main features of my invention, have
a knife clamp hinged on top of a clamp frame and substantially rectangular
thereto, and this clamp frame is mounted on the grinding wheel frame in front
of the face of the clamp, and one or the other of said frames is swiveled with
reference to the other, or both are swiveled, so that said clamp or said wheel,
can swing or be moved in the arc of a circle centreing somewhere within the body
of the grinding wheel, and this peculiar construction is a characteristic feature of
my machines. While I prefer, and in most cases employ, an actual guiding bolt
or pivot for thus swiveling or coupling the clamp frame and knife frame together;
that form of guide need not necessarily be relied upon for confining the movement
of either frame as described, because a segmental guide as the equivalent of the
actual pivot, will also serve as a swiveling pivot, as will hereinafter be made fully
apparent.
When the bolt pivot is employed, it obviously cannot be placed within the body.
of the stone or wheel, but its centre of motion can be thus located by hinging
said two frames so as to limit them to the same plane, while either is swinging,
by means of a hinge pivot outside of the grinding wheel, opposite the centre of its
face, and rectangular to its axis, and for the best results a small wheel is used;
and the knife seats are located on the clamp, so as to present a knife against the

page_text: face of the wheel at or about 90 degrees from the line of said bolt or pivot, so that
said clamp in swinging around the face of the wheel from one angular position
to the reverse angle, will surely move in the arc of a circle, centreing within the
body of the wheel. Whether the pivot, or the segmental guide be used, as the
swiveling coupling, the knife clamp can be relied upon for the first time in a
mower knife grinding contrivance, of the class embodying wheels or stones having
flat or rectangular grinding faces, for consecutively presenting the coincident edges
of any two knife sections in precisely the same manner, and with precisely the
same relations to the grinding-surface, at the two edges of the face of the grinding
wheel.
My
It has heretofore been proposed to grind the knife sections while the knife is in
position on the finger bar of a mowing machine, and machines for this purpose
have been heretofore devised and patented. These machines have been provided
with a clamp, by which they can be mounted upon the finger bar with and without
the latter being clamped with the grinding machine firmly upon the ground.
machines cannot be used upon a knife unless it is detached from the mowing
machine, but I have specially provided for convenient service in the field by
mounting my machine upon a base clamp so that it can be clamped to the traction
wheel of a mowing machine when at rest, or to any other portion of the machine
presenting similar surfaces. I have also devised a novel method of and means
for applying water to porous grinding wheels, as well as a variety of novel features
in construction, all of which will be duly specified in the several clauses of claim
hereunto annexed.
Referring to the Drawings.
Figure 1 in side view illustrates a complex form of machine embodying my
complete invention, with the several parts of the machine so constructed and
organized, as to afford a great variety of, adjustments, and enable corresponding
variations in the mode of working it.
Figures 2, 3 & 4 illustrate in opposite side and plan views, a simpler form of
machine, with my complete invention embodied therein, but with the parts
constructed and organized with reference to simplicity, economy, and convenient
operation.
Figures 5 & 6 are respectively enlarged front and rear views of the knife
clamp and its frame, and the base clamp of the machine shown in Figure 2,
the grinding wheel being removed, and a portion of its frame shown in cross
section.
Figure 7 is a vertical central section of the parts shown in Figures 5 and 6,
with a mower knife, clamped in position preparatory to grinding.
Figure 8 is an enlarged sectional view of the grinding wheel and its frame on
line x, Fig. 3.
Figure 9 is a similar view of the grinding wheel frame on line y, Fig. 3.
Figure 10 in side view and section illustrates a form of machine embodying my
invention, and in which the grinding wheel frame is integral with portions of the
base clamp, and having a separate lever for reciprocating the wheel.
Figures 11 & 12 in side and end views illustrate a machine having no base clamp,
a grinding wheel frame correspondingly modified in its construction, and with a
knife clamp frame adapted to use therewith in accordance with my invention.
Figures 13 & 14 in side and top view, illustrate a simple form of machine
embodying certain features of my invention, and in which the clamp frame and
wheel frame are coupled by a segmental guide instead of by means of
pivot bolt as in each of the other forms.
a guiding
Figure 15 is a diagram illustrating the grinding wheel in top view, the arc of
the circular path, to which either the grinding surface, or the knife is limited,
while shifting from one angular position of adjustment to the other, and also the
centre of said circle located within the body of the wheel or stone, this figure being
applicable to either of the forms of machine illustrated..

page_text: Figures 16, 17 & 18 are diagrams similar to Fig. 15 applicable to all of the forms
of machine shown, and in each case illustrate a portion of a grinding wheel in top
view, and a mower knife in contact therewith, and said figures respectively.
indicate the relative positions of knife and wheel, while griuding one edge at
the bottom of a V-between two knife sections; next while grinding the middle
of the edge; and finally while grinding at the tip. Dotted lines in each figure
indicate the relative positions of the knife and wheel during corresponding
operations at the opposite or coincident edge of the adjoining knife section.
For explaining that portion of my improvement which relates to the peculiar
relations of the knife clamp and grinding wheel I will, generally refer to and
describe the parts of the machine necessarily involved, and at this time describe
specifically only such features in construction as essentially relate to this branch of
my invention, and in doing this I deem it best to refer to one of the simple forms
of my machine, as, for instance, that shown in Figures 2, 3 & 4.
The rectangular faced grinding wheel A is mounted in its frame B, and provided
with means for rotating it.
The knife clamp C is rectangularly mounted upon its frame D, and is essentially
capable of vibration toward and from the face of the grinding wheel, and of rigidly
holding, and wholly supporting a mower kuife therein.
Either the knife clamp frame, or the grinding wheel frame, may serve as a bed
plate for the machine, in which case, it is or may be provided with a base clamp,
but these particular features are immaterial in this connection.
1
It is essential that the grinding wheel frame B, and the knife clamp frame D, be
hinged together in some way, in order to admit of varying the angular relations of
the knife clamp and grinding wheel, and this feature broadly considered, is present
in very many prior machines, but in all of said prior machines, the axial pivotal
connections for uniting said frames, have been located on the knife clamp side of
the machine, more or less remote from the wheel, and as herein before stated, an
important novel feature in construction by me, consists in hinging said two frames
together, by or upon a pivot E, which is located within the plane occupied by the
centre of the grinding wheel, and in its best form substantially radial to the centre
of the axis of said wheel. As a result of this novel feature in the construction of
a mower knife grinder the relations of the rectangular face of the grinding wheel,
and the knife, are uniformly maintained, regardless of their angular variations in
adjustment, because the wheel or the knife clamp frame, as the case may be,
vibrates around the centre of the wheel, and in the plane of its axis, in swinging
from one extreme angular position to the other. The grinding wheel frame and the
kuife clamp frame, thus hinged together, in the plane of the centre of the grinding
wheel, in order to be highly effective, must be employed with a knife clamp, which
is mounted substantially at right angles to its frame, and substantially parallel
with the pivot which couples said frames so that said clamp can swing on a hinge
joint at its foot, toward and from the face of the wheel, for presenting the knife,
while rigidly held in said clamp, to the grinding surface, at a point thereon, which
is about 90 degrees from the radial line occupied by the pivot on which the two
frames are hinged together, as clearly shown in the drawings.
In addition to the rotation of the grinding wheel and the capacity of the knife
clamp to move outward and from said wheel, either the knife clamp or the wheel,
must also be capable of a reciprocating movement, in a plane substantially parallel
with the frame pivot E.
So far as relates to this portion of my invention, it is immaterial whether the
grinding wheel be thus reciprocated, while revolving, or the knife clamp be
correspondingly reciprocated, while the wheel be revolved, without reciprocation,
as will hereinafter be more fully described.
The grinding wheel A has a rectagular flat face or periphery a, which
constitutes the grinding surface. The width of this face, for obtaining the best
results, should be but little wider than one half the width of the widest knife

page_text: section; as, for instance, I find that a wheel one inch and three quarters wide at
its face, will operate to the best advantage regardless of the well known slight
variations in the width of mower knife sections.
The diameter of the grinding wheel may be widely varied, but its dimensions in
this respect, should of course correspond with the dimension of the framing of the
machine, but when convenient portability and economy are in view, I avoid heavy
framing, and consequently use a grinding wheel about six inches in diameter, the
machine being adapted to work with substantial uniformity, until the wheel by
abrasion, has been-reduced-to_say_five inches in diameter, at which time a new
wheel should be applied. The material of the wheel-may-be-indefinitely varied
without departure from certain portions of my invention, but certain other portions
thereof depend upon a porous abrasive material, such as the well known free grit
natural sandstone, or certain well known varieties of artificial grinding wheels,
which are free absorbents of water.
I have discovered in this connection, that a grinding wheel composed of proper
material, and proper size, can be relied upon, not only to carry water within it, but
also to automatically deliver it to its grinding surface when revolved at such speed,
as is desirable for grinding, and in doing so to maintain a cleaner and cooler
grinding surface, than when water is applied in the usual manner.
Referring to Figure 8, it will be seen that the grinding wheel A is chambered
at a¹, and mounted upon a hollow-hub a², having an integral flange a³, near one
end, and a movable flange a at its opposite end, and that the wheel is firmly
clamped between said flanges, by the nut a³ (which in this case is also a gear) so
that said flanges serve as the side walls of a reservoir for water within the stone,
which is rendered accessible for filling, by way of the screw plug a, in one of the
flanges. Centrifugal force, induced by the rotation.of the wheel at desirable speed,>
causes the water to pass radially through the stone, and out at its grinding face.
The quantity of water capable of being thus delivered, is ample to secure good
results in grinding, and one charge of water will serve for many hours of actual
service. The wheel, with its hub, is loosely mounted upon a non rotative shaft a',
and the interior of said hub, is centrally chambered to afford at each end of the
hub, a limited but ample contact with the shaft, and also an oil space a³.
The manner of mounting the grinding wheel upon its frame B, may be widely
varied without departure from certain portions of my invention. It is, however,
essentially mounted with its shaft located at the end of an arm B¹, constituting a
part of the wheel frame whether these last named parts be pivoted together or
rigidly united, although in its best form said parts are hinged as at b, on a pivot
which is parallel with the axis of the wheel, and in this case said pivot may also
serve as a stud on which a hand crank b¹ is mounted. The wheel arm B is slotted
longitudinally in front of the crank stud, and embraces the grinding wheel, which
is so mounted that its non-rotative shaft is supported at each of its ends by the
frame arin.
The crank and the gear nut a³ on the grinding wheel are rotatively
coupled by a chain of gearing which is mounted on the side of the wheel arm,
but said gearing may be largely varied in character and arrangement, without
departure from my invention. I find, however, that gearing so organized as to
impart to the grinding wheel eight revolutions to one of the crank is well suited
for my purposes. A curved guard plate or shield be overlies the wheel. When a
solid wheel is employed, the usual dripping water cup may be relied upon. The
non-rotative wheel shaft, or rod a', has a head at one end, and a transverse locking
pin at the other, so that it firmly braces the two sides of 'the wheel arm and locks
them together and serves in fact as a detachable part thereof, by means of which
the wheel can be readily removed and replaced.
With the wheel arm pivoted at b, a provision is requisite for reciprocating the
wheel vertically, while revolving, and this is conveniently accomplished by
extending the rear end of said arm so as to form a lever, and providing it at its
outer end with a handle c. For preventing the contact of the face of the wheel

page_text: svith its frame, adjacent to the pivot E, as when said wheel is at rest, I provide the
wheel arm at its underside, with a stop stud c¹, which by contact with the top of
the frame B, limits the downward movement of the wheel.
The knife clamp frame D in this form of machine, is a skeletonized casting,
substantially rectangular at its front and sides but is extended centrally at the
rear. At the front side there is a tubular sleeve or bearing for the reception of
the pivot E by which the frames B and D are hinged together, and it will be seen
that this pivot occupies substantially the same plane as the centre of the wheel,
and that it is substantially radial to the axis of said wheel, when in working
position as herein before referred to.
At each end of the frame D, as well shown in Figures 5, 6 and 7, it is extended
upwardly for affording short lugs or ears d, which serve as standards for the
reception of a rod or bar d', which is higher than the pivot E, but at the rear
thereof, and at right angles thereto, and on this rod or bar d¹, the knife clamp C is
hinged so as to stand substantially perpendicular to the upper side of the clamp
frame D, and be free to swing toward and from the face of the grinding wheel.
Whatever the character of the knife clamp, it must gripe a mower knife F, firmly,
and with the knife bar f, toward the base or clamp frame D, and be adapted to
present the knife sections, with their beveled edges toward the grinding whool,
and with the junction of any two knife sections opposite the centre of the clamp
and also opposite the centre of the grinding wheel face when the latter and. the
knife are parallel with each other, as indicated in Figure 3, wherein the wheel and
knife are shown in position preparatory to the angular adjustment essential for the
grinding operation. It will now be readily understood that by swinging the
grinding wheel toward the right hand, the junction of the two knife sections
opposite the face of the wheel will be placed at the left hand edge of said wheel,
and the edge of the right hand section located in position for grinding; and also
that when the wheel is swung toward the left hand, said junction of the two knife
sections will be placed at the right hand edge of the wheel, and the edge of the
left hand section, located in position for grinding. This capacity for successively
presenting the two consecutive edges of any two knife sections, to a flat faced
grinding wheel, by a mere change in the angular relations of a knife clamp frame,
and a grinding wheel frame, and without readjustment of the knife in its clamp or
varying its position therein, I believe to be novel. It is obvious that the movement
of the two frames by which the angular adjustment is effected, must be precisely
limited in both directions, and this I accomplish by providing a stop e, clearly
shown in Figure 7, which may be located on that one of the two frames which has
the free swinging movement on the pivot E. As here shown, said stop is a
projecting finger integral with or attached to the wheel frame B, and projecting
from near the pivot E, toward the clamp frame D, so that by its contact with the
clamp frame at or near the inner sides of either of the lugs & thereon, the wheel
frame is restricted to the proper range of movement, for securing the desired
precise angular adjustment of the knife and wheel.
While the construction of the knife clamp C may be largely varied, without
departure from certain features of my invention, the one illustrated has been
devised by me and contains certain minor features of invention.
This clamp is composed of two main parts, which I will term the platen g and
the clamping jaw h, and both are skeletonized for rendering them as light as
possible. The platen g is or may be a single casting, having legs hinged at their
bases upon the bar & mounted on the lugs d on the frame D. It has a ledge or
knife. seat g on which a mower knife F is supported edgewise, and with its bar f
on said seat; and it has also two narrow knife seats g, g, at right angles to the
first, and these are so separated, and located, as to afford bearings for the rear or
back side of the knife, and at or near the centre of any two successive knife
sections. At its top or free end the platen g is curved rearwardly from the knife
Beats, and is provided with a spiral cam face g³, having a central hole therein, At
'

page_text: right angles through the knife seat g₁ at its centre, there is a hole occupied by a
threaded bolt or screw g* having at its top a rectangular non rotative head g³
parallel with said knife seat, and below said seat said bolt has a nut go by which
when a knife F is in position on its seat, its bar f can be firmly clamped between
said head go and the seat g¹. This clamping bolt g* need not always be used for
actually clamping the knife. bar, but can generally be relied upon when between
its head and the knife seat g', a mere recess is provided for the proper reception of
-knife bars of various widths.
On top of the bolt-head.g, and at its centre it has a gage point go, by which the
longitudinal adjustment of a knife in the clamp is accurately gaged by locating
the junction of any two knife sections exactly in line with said gage point.-
The clamping jaw his also skeletonized and is preferably in one casting, and has
two legs which are hinged upon the bar d alongside of the legs of the platen g.
At its outer or free end these legs are united by a rearwardly curved cross bar h¹,
which has at its ends, two rigid clamping fingers h³ extending toward the bed plate
and also toward each other so as to overlie the two knife seats g², g³, of the platen g
and afford ample intervening space for the reception of knife sections.
At the
centre of the curved cross bar h there is a transverse hole occupied by a headed
bolt, having its threaded shank passed through the hole in the centre of the cam
face g, at the free end of the platen g, and tapped to the outer end of said bolt
there is a cam faced nut h, by turning which, on the cam face g³, the seats g², g²,
and the coincident faces of the clamping fingers h², h², are promptly forced toward
each other, and enabled to heavily grasp and rigidly clamp one or two interposed
knife sections. The bolt ³ is non rotative, having a square, shank and occupying
a square hole, so that by taking it out, partially rotating it, and reinserting it, the
cam nut can be made to occupy different longitudinal positions on the bolt, and
thus provide for rigidly clamping knife sections regardless of variations in thickness.
For enabling a prompt release of the knife by the separation of said seats and
fingers, an expansive spiral spring 5, is introduced between the platen g, and jaw h,
and it is conveniently mounted upon the bolt h³. The knife when thus held in the
clamp is substantially horizontal, and although during the grinding operation it is
inclined slightly from its bar to the tips of its sections, it is yet substantially
horizontal. So long as the clamp can engage with two knife sections, it will firmly.
hold the knife, but in grinding the outer edge of the last or outer knife section, the
clamp can only engage with that one section, and for maintaining the knife firmly
in position, the clamp button i is used. This button i, is pivoted upon the outer
side of the knife seat g¹, and at one end thereof, so that by swinging it upward it
will forcibly engage with a knife and co-operate with the adjacent knife seat g³,
and clamp finger ³, for firmly holding the knife in position.
As thus far described, the machine can be used to good advantage even if two
persons be required to operate it, one for turning the grinding wheel, and the other
for moving the clamped knife toward and against the wheel, because neither of
said persons need to be skilled grinders, inasmuch as the holding of the knife is
wholly automatic, and the adjustment of knife and wheel involve no manipulation
of the knife whatever during the grinding operation. All that is required for
enabling one person to do the work, as well as two could do it, is to provide the
knife clamp with a spring, which will move the clamp toward, and force the knife
against the grinding wheel, and hold it there under proper pressure. Knife clamps
for use with flat faced grinding wheels have heretofore embodied springs, but in
all prior contrivances known to me, for grinding mower knives on flat faced wheels,
the knife must be manipulated during the grinding operation, either so as to
provide for keeping a knife section next to the one which is being ground, away
from the edge or side of the stone or wheel, or for determining the bevel on the
knife section, or for sweeping the beveled edge to and fro on the grinding surface,
or for controlling the knife in some way. I apply an expansive spiral spring k,
which is seated at one end upon the clamp frame D, which has a spur k¹ at its rear
'
'

page_text: edge, and at its other end, said spring abuts upon a nut 3, on the bolt g', of the
platen g, so that said bolt occupies the interior of the spring, and confines it in
place, said nut serving as an adjustable spring seat whereby the power of the
spring may be variably applied.
the
It is obvious that changes in the angular adjustment of the clamp and wheel,
while the knife is in contact with the wheel, would be liable to injure the knife
edge, and therefore the clamp should be moved rearward preparatory to making
these changes, and this can be conveniently done by hand, although I have devised
automatic devices for this purpose. At a short distance above its hinge rod
clamp, has an outwardly projecting cam faced cross bar d', with a central notch
therein. The frame B has a rigid finger d³, projecting beyond and above the
pivot E, and has its outer end in the same plane occupied by the cam face d², so
that when the wheel frame is swung around, said finger at its end sweeps the cam
face, and at once forces the clamp rearwardly from the stone, and when said finger
reaches and enters the central notch, the clamp frame is held in the position
indicated in Figure 2, and a release from said notch may be effected by a continued
swinging movement of the wheel; or by pressing the clamp rearward by hand.
The finger d³, and the stop e, before described, have in some cases a shank common
to both, and they are both integral with the frame B; but these are mere incidents
in construction.
This general form of machine as thus far described may be variously mounted
upon any suitable support, without departure from the main features of my
invention, but I have provided it with a base clamp G by which it may be mounted
on a bench or table provided with a suitable surface, or so that when used in the
field it may be firmly mounted on the traction wheel of a mowing machine. The
knife clamp frame D in Figures 2, 3 and 4, has in front, serving as portions of said
base clamp G, two pendant integral fixed jaws 1, and also with two lateral cars
near its rear side, and each pair of these has a hole for receiving a non rotative
threaded bolt m. Two movable jaws n of the base clamp are cast in one piece,
and each jaw n has a rectangular integral guiding finger n', which extends toward
the coincident fixed jaw, and at its outer end bears with a concave face, upon the
top of its clamp bolt m at a non threaded portion thereof. Each bolt has a thumb
screw o. The two movable jaws are mounted on the bolts and are guided truly '
thereon by the fingers n³, thus enabling the machine to be rigidly mounted on any
firm foundation presenting substantially parallel and rectangular surfaces of various
widths. As herein before indicated it is not new to provide a grinding wheel frame
with a clamp by which it may be attached to a finger bar for field service, but
I am the first to provide a machine embodying a wheel frame and a knife clamp
and its frame with a base clamp, whereby the whole may be mounted upon a
mowing machine, so that the latter may be used as a work bench, while grinding
knives detached from the finger bar.
While I prefer the simple form of machine shown in Figs. 2, 3 and 4, it is to be
distinctly understood as herein before indicated, that it will be within certain
portions of my invention if the grinding wheel have no laterally swinging capacity
provided the knife clamp frame, and the wheel frame can be guided in the arc of a
circle, as when hinged on a pivot arranged as before described, as for instance as
illustrated in Figure 10, the grinding wheel frame B is integral with a portion of
the base clamp, or other suitable base plate, so that it has no lateral swinging
capacity. In this case the clamp frame D, as before described, except that it is
disconnected from the base clamp and is hinged to the wheel frame B, upon the
pivot E, which as before described, is in a line substantially radial to the centre of
the axis of the grinding wheel, and at right angles to its shaft, and therefore when
the clamp frame is swung to the right hand or the left, it will present a knife
to the two edges of the grinding wheel, precisely in the same manner, as when
said wheel is capable of swinging. When thus organized the stop e, as before
described, projects from the frame B, near the pivot E, but in this case it is

page_text: stationary, and it is abutted by either of the two hinge lugs & on the knife clamp
frame D, when the latter is swung into either of its two angular positions of
adjustment.
In this form of machine the cam faced bar d³, and the finger d³, on the frame B
operate as before described, for automatically throwing the knife clamp rearward
during the changes in its angular adjustment. When the wheel frame is thus non
pivoted, the wheel arm need not have an extension to serve as a lever but the
wheel may be reciprocated by means of a separate lever pivoted on the frame B,
and having at its inner end a pin occupying one or more-guide-slots-on-the-under-
side of the wheel arm, and at its outer end, a handle c.
Although my machine in its best form has a grinding wheel which while
revolving is vertically reciprocated, it is to be understood that without departure
from certain portions of iny invention, said grinding wheel: may be limited to a
rotative movement, and the knife clamp frame be reciprocated in lieu of thus
moving the wheel. The extent of this reciprocating movement of the wheel at its
grinding face, need seldom be more than two or two and one-half inches, and a
vertical reciprocation of the knife clamp to that extent, can be readily provided
for, and easily controlled. As, for instance, I will now refer to Figure 1, wherein
1 show a complex.machine embodying all of the features of my invention.
In this case the base clamp G is separately constructed to serve as a base, and
the pivot E is integral therewith, or rigidly mounted thereon, and preferably larger
and heavier than would be required in either of the other two forms of machine.
The wheel frame B as before described, is hinged upon said pivot E, but is
provided with set screws p, by which it may be rigidly secured to said pivot. The
wheel arm B¹ is hinged as before described upon the frame B, but at its pivot bit
is provided with one or two pendant cheeks b³, having holes therein for the
reception of the locking pin 6 by which said arm may be rendered immovable on
its pivot b.
7
The knife clamp C is as before described, but its frame D is composed of two
parts, one having lugs. d on which the knife clamp is mounted on the rod d¹,
precisely as before described, and the other a bed frame g, which is directly hinged
to the pivot E, and has a set screw q', by which said frame may either be immovably
fixed thereon, or permitted to swing. In the two forms of machine previously
described, the wheel is normally depressed, and must be raised for traversing the
edge of a knife section, and therefore the clamp must be normally elevated, and
then depressed for obtaining this traversing action. This is accomplished by
providing the clamp. bed frame q with a pair of parallel vertically curved tail
pieces q, and hinging the knife clamp to them, by means of similar tail pieces, the
pivot being at such a point from the face of the stone or wheel, as will enable the
clamp to move in the same circular arc in which the grinding surface of the wheel
is moved in one of the other forms of machine.
In both of said other forms, the wheel drops to its lowest or normal position by
gravity, but in this machine the clamp is elevated to its normal position by the
expansive spring r, which is interposed between the two parts of the clamp frame;
and for reciprocating said clamp, a hand lever s pivoted to the frame B is coupled
to the base of the clamp above the bed frame q by means of a flexible link 8'.
A hooks on the frame B, for engaging with the lever s will firmly hold the clamp
frame in a depressed position when desired.
In this form of machine, the stop e is as before described, but instead of abutting
against the hinge rod ears d, other pendant ears d, are provided for that purpose
on the bed frame q.
The cam faced cross bar d' is also here used as well as the finger d³, but as this
latter can only be used when this machine is adjusted to operate like the other two
forms of machine described, said finger is movable on a locking pivot so that it
can be swung out of the way, except when desired for service.

page_text: It will be readily obvious, if the knife clamp frame D, be locked by its set
screw q, to the pivot E, the frame B, unlocked therefrom, the knife clamp depressed
and held by the hook 83, and the finger d³ swung around to the front and locked in
position, and the wheel arm B₁ released by removing the locking pin 64, and the
latter then placed in the hole 65 in the tail pieces of the clamp frame, that the
machine will then be capable of operation precisely the same as with the form
illustrated in Figure 2. If now the frame B, be locked to the pivot E, by its set
screw p, and the clamp frame unlocked therefrom the machine will be capable of
being operated as with the form shown in Figure 10.
It is to be understood that the proportion of the grinding wheel face to the
width of the knife section may be considerably varied without rendering the
machine useless, so long as the flat grinding face is traversed to and fro evenly.
The hinge pivot E may also not be arranged so as to be exactly radial to the centre
of the axis of the grinding wheel, so long as it is rectangular to the shaft of said
wheel, and the knife clamp stands substantially parallel with said pivot, and the
latter is located below said clamp beneath the wheel and opposite the centre of its
grinding face, so that said wheel will be partially interposed between the knife
held in the clamp, and said pivot, thus making some point within the wheel, the
centre of motion by which the angular adjustments are effected.
It is further to be understood that the main features of my invention do not
depend upon any particular mechanism for driving the grinding wheel, and that
accelerating gearing is only required with a wheel of small diameter, so as to afford
a desirable speed at its grinding surface, as, for instance, when a larger stone is
operated by means of a treadle, like an ordinary grindstone, and for further illus-
trating what wide variations can be made in the form of machine without departure
from the main features of my invention, I will refer to Figures 11 and 12.
In this machine the grinding wheel or stone A is or may be like an ordinary
grindstone of suitable character, and it is mounted in its frame B in the usual
manner, so as to stand upon the floor or the ground, and is provided with a water
trough, crank, pitman and treadle, all in a manner well known, except that the
frame B is so constructed as to leave the front portion of the stone accessible for
properly mounting the clamp frame D upon its pivot E, as before described,
beneath the stone and coincident with the centre of its face. The knife clamp C
is precisely as before described, and is also arranged to reciprocate vertically, but
instead of being pivoted for that purpose, it has projecting from its base at each
side two vertical flat wings or bladest which occupy and snugly slide in vertical
slots in the clamp frame, as clearly shown, and the clamp is supported on a
spring, so that the latter will maintain the clamp and its knife in its normal
elevated position, and said clamp is provided with a handle so that it can be con-
veniently reciprocated vertically by hand, while the wheel is revolved by the foot
of the operator.
It is to be further understood, as herein before indicated, that. the form of the
swiveling connection, between the clamp frame and the wheel frame, may be
widely varied without departure from the main features of my invention, and as
an illustration of one such obvious variation, I will refer to Figures 13 and 14 for
indicating how readily the centre of motion by the clamp frame is located within
the body of the grinding wheel without the use of a pivot in the form of a rod or
bolt hinging said frame to the wheel frame. In this form of machine the wheel A,
its frame B, and the knife clamp C, are in no essentials different from those in the
forms of machine before described.
The knife clamp frame D is different in form, but the clamp is hinged thereto
as before described., In this case the clamp frame is provided on its underside,
with a dovetailed or T. shaped block segmental in form, which occupies a seg-
mental guiding groove on a bed plate integral with the wheel frame, and said slot
snugly receives said block, but permits the latter to slide horizontally therein. This

page_text: groove E¹ is an arc of a circle sweeping across the face of the wheel, and having its
centre within the body of the wheel, as clearly indicated in dotted lines.
}
It will be obvious that the pivot E in all the other forms of my machine, is a
convenient and desirable form of guide for limiting the movement of the clamp, or
the wheel, as the case may be, to the arc of a circle centreing within the body of
the wheel, and that the segmental grooved guide E¹, is in substance a portion
of the periphery of a large pivot, which like the pivotE, has its axis located sub-
stantially in a line radial to the axis of the wheel, and at right angles thereto. In
this form of machine the grinding wheel arm B¹ is pivoted on the frame B, but this
latter as in Figure 10 is immovable, and the wheel-is-reciprocated-as-shown_in..
Figures 1 and 2, although a separate lever may be employed for that purpose, as
shown in Figure 10. The stop e operates as before described in connection with
the ears on the clamp frame, and so also does the finger d³ co-operate with the
cam faced bar d for throwing the clamp rearward as before described.
Machines constructed in either of these forms will rigidly hold a knife against
any movement, independently of the movement, of its clamp and the clamp frame.
The knife in each is wholly controlled during the grinding operation by the
spring at the base of the clamp, no manipulation of the knife being required,
except after two coincident edges have been ground, and then only for moving the
knife longitudinally. The clamp in each machine is guided in the same circular
path for presenting a.knife, in precisely the same manner, at both edges of the
grinding wheel, as illustrated in Figure 15, and while grinding, the contact points
between the knife and grinding, wheel, traverse alternately to and fro, evenly
across the face of the wheel, and each portion of each knife section edge is ground
upon a corresponding portion of the wheel face, as illustrated in Figures 16, 17
and 18, and hence the grinding surface is always worn evenly, the edges of the
wheel preserved, and the grinding performed with the greatest practicable
uniformity. With either of these machines the coincident edges of any two knife
sections can be consecutively ground by merely changing the angular adjustment,
and so far as my knowledge extends.this.cannot be done with any prior grinding
machine or grindstone attachment without also changing the longitudinal adjust-
ment of the knife in its clamp.
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
First In a mower knife grinding machine, the combination substantially as
herein before described, of a rectangular faced grinding wheel, and a knife clamp
respectively mounted on separate frames which are swivelled together and movable
in the arc of a circle centreing within the grinding wheel in front of the clamp
and its frame, and with said centre substantially coincident with the centre of the
peripheral face of the grinding wheel, whereby in changing the angular relations
of the grinding face and a knife held in said clamp, either said face or said knife
will be moved in the arc of a circle centreing in front of the clamp and within the
body of said wheel and enabling the two coincident edges of any two knife
sections to be consecutively ground at opposite edges of the wheel without handling
the knife.
Second: In a mower knife grinding machine the combination substantially as
hereinbefore described of a grinding wheel having a rectangular grinding face at
its periphery, a mower knife clamp and frames for said clamp and wheel, which
are hinged together by a guiding pivot which is substantially radial to the centre
of said wheel and rectangular to its axis.
Third In a mower knife grinding machine, the combination substantially as
herein before described, of a knife clamp frame, a knife clamp for rigidly holding
a mower knife bar and its attached knife sections, and hinged on top of said frame
substantially at right angles thereto, a grinding wheel frame, a pivot rectangular

page_text: to the knife clamp hinge, for. hinging said two frames together and a grinding
wheel having a flat faced grinding periphery mounted in its frame, and having a
portion of its periphery interposed between said pivot and the knife seats of tho
clamp, and on an axis rectangular to said pivot.
Fourth In a mower knife grinding machine the combination substantially as
hereinbefore described of a spring backed knife clamp, a grinding wheel, having
a flat peripheral grinding faco and separate frames for said clamp and wheol which
are essentially hinged together upon a pivot substantially parallel with the knife
clamp and rectangular to the axis of the grinding wheel and substantially radial
thereto.
Fifth In a mower knife grinding machine, the combination substantially as
herein before described, of the knife clamp, the grinding wheel having a flat
peripheral grinding face, and means for reciprocating either of them the frames on
which both are mounted, and a pivot substantially opposite the centre of said
wheel, and rectangular to its axis for hinging said frames together.
Sixth-In a mower knife grinding machine, the combination substantially as
herein before described, of a spring backed knife clamp, a knife clamp frame on
which said clamp is hinged at its base, a grinding wheel frame, a pivot for hinging
the latter to said clamp frame, and a rectangular faced grinding wheel on an arın
hinged to its frame, and mounted on a shaft which is parallel with its arm hinge
axis, and at right angles to the pivot by which said two frames are hinged.
Seventh-In a mower knife grinding machine, the combination of a knife
clamp, a knife clamp frame, a grinding wheel frame, a pivot hinging said frames
together, and a grinding wheel having a rectangular grinding face or periphery
slightly wider than one half the width of a knife section and mounted on a shaft
which is substantially in line with said pivot and rectangular thereto.
Eighth In a mower knife grinding machine the combination with a knife
clamp of the rectangular faced grinding wheel, its shaft, its arm having bearings
for both ends of said shaft, the gearing on said arm, the crank, the lever or handle
at the outer end of said arm and the frame on which said arm is hinged,
substantially as described.
and
Ninth In a mower knife grinding machine, the combination of a grinding
wheel, and its hub, a slotted wheel arm mounted upon a supporting frame, a non-
rotative detachable shaft for said wheel supported at both ends by said arm,
the gearing and crank mounted on said arm for driving said wheel substantially
as described.
Tenth The combination with the grinding wheel of the mower knife-clamp,
having the platen g, the clamping jaw h, having rigid fingers, a ledge or seat for a
knife bar, the knife section seats opposite said fingers, the cam faced clamping nut,
and the bolt connecting it with the jaw h, substantially as described.
Eleventh The combination substantially as described of the rectangular faced
grinding wheel, the knife clamp the wheel frame, and knife clamp frame, hinged
together by a pivot, substantially radial to the axis of the wheel and a stop by
which the hinging movement on said pivot is equally limited in both directions.
Twelfth The combination substantially as herein before described, of the knife
clamp frame, the knife clamp hinged thereto, the grinding wheel, the grinding
wheel frame hinged to a clamp frame on a pivot substantially radial to the wheel,
a cam faced bar on said clamp, and a finger on the wheel frame coincident with
Baid cam faced bar for engaging therewith and forcing the clamp away from the
wheel during changes in their angular relations.
Thirteenth In a mower knife grinding machine, the combination with the
grinding wheel of the knife clamp provided with rigid fingers for engaging with
the knife sections, and the ledge or seat for the knife bar, extended laterally from
below said fingers, and a clamp button on said seat near its end for engaging with
the front of a knife at its rear edge, and thereby co-operating with one of said

page_text: clamp fingers for firmly holding the knife in position whilst its end section is
presented to the wheel for grinding.
Fourteenth-In a mower knife grinding machine, the combination substantially
as herein before described, of a grinding wheel containing a central water chamber
and a pair of flanges which serve as the side walls of said chamber and by which
said wheel is clamped and supported concentrically with relation to its axis.
Fifteenth In a mower knife grinding machine, the combination substantially
as hereinbefore described, of a grinding wheel provided with a central water
chamber, a tubular hub provided with flanges for centreing and clamping said
wheel, whereby said wheel may be mounted upon a stationary shaft.
Sixteenth-In a mower knife grinding machine, the combination of a grinding.
wheel and its frame and a knife clamp and its frame, couplings by which said
frames are swivelled together, and a base clamp, substantially as described whereby
the machine may be mounted for service upon and clamped to a mowing machine
wheel or other suitable foundation.