Improvements relating to Lawn Mowers.
Year: 1898

page_text: Date of Application, 17th May, 1898-Accepted, 17th Sept., 1898
COMPLETE SPECIFICATION.
Improvements relating to Lawn Mowers.
1, WILLIAM PHELPS LESHURE, of No. 214, North Street, in the City of Spring-
field, County of Hampden, State of Massachusetts, United States of America,
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 relates to devices for sharpening lawn mowers and analogous
machines of the type in which a rotary knife is used; and the object of the in-
vention is to produce an improved sharpening device for the rotary knife of such
machines which can be applied thereto and be used to sharpen the blades of the
rotary knife while the machine is in operation, and which can readily be adjusted
out of contact with the knife, as soon as the sharpening operation is completed.
The invention consists in the construction shown and described in the follow-
ing drawings and specification, and pointed out in the claims.
In the drawings forming part of this specification,―
Figure 1 represents a top plan view of a lawn mower having my improved
sharpening device applied thereto.
Figure is a sectional elevation of a lawn mower taken on line 2-2, Figure 1,
and looking to the right on said line.
Figure 3 is a plan and end elevation of a lawn mower having the knife-sharpen-
ing device applied in front thereof instead of on the top of the knife, and said
figure shows a slightly different arrangement of the parts.
Figure 4 shows a modified construction of the screw-operated fastening device
for supporting the sharpening device on lawn mowers of a different construction
to that shown in the other figures.
Referring to the drawings, A represents the frame of the lawn mower having
the driving-wheels B, and a rotary knife C, supported and driven in the usual
manner. Drepresents the transverse brace-rod of the machine to which may be
secured the sharpening device which is the subject of this invention. Said sharpen-
ing device consists of two supports 2, 2, having dove-tailed transverse grooves 3,
therein, for the reception of a sharpening stone 4, formed with beveled edges to
correspond with the said dove-tailed groove 3, in the said supports 2. Said stone
fits snugly therein and is rigidly supported thereby in a position parallel with the
axis of the rotary knife C.
A screw-operated fastening device is provided on which said supports 2, 2, are
pivotally supported, and said fastening device, of necessity, varies in form some-
what according to the design of the lawn mower, or according to the location of
the sharpening stone 4, relative to the periphery of the rotary knife C.
Figures 1 and 2 show the stone applied to the top of the knife C, and Figures 3
and 4 show the stone applied to the knife in front of it and at right angles to the
position shown in Figures 1 and 2.
In either case, the stone must be spring-held against said knife to insure the
most effective operation thereof and to avoid injury to the knife, and these two

page_text: positions being reversed, the one relative to the other, necessitates the application
of the spring in one case on one side of the pivotal support of said supports 2, 2,
and in the other case on the opposite side of said pivotal support.
Hence, in the construction shown in Figures 1 and 2, (which is the preferred
construction) the screw-operated fastening device consists of a casting E, having
the rigid jaws 5, and through one of said jaws a screw: 6 passes whose inner end
engages the brace-rod D of the lawn-mower, the jaws 5 opposite the end of said
screw being slightly V-shaped, as shown at 7, to insure a firm grip on said brace-
rod of the screw 6.
An arm or extension 8 of said casting E extends over said knife C horizontally
at right angles to the axis thereof and in the extreme end thereof is located the
vertical adjusting-screw 9.
Near said screw and between it and the screw 6 is a boss 10 on the underside of
said arm 8, and an upstanding boss 12 on said support 2 is located near one end
thereof.
- I
A pin 13 passing through said bosses 10 and 12 pivotally unites said support to
said fastening device.
The end 14 of said support is extended outward under said screw 9, whose end
bears thereagainst, and a spring 15 on the opposite side of said pivotal support
and compressed between the support 2 and the arm 8 of the fastening device, serves
to hold said end 14 of the support in contact with the end of the screw 9, whereby
the manipulation of the latter moves said support on its pivot-pin 13, as desired,
to effect the contact of the stone with the knife C, to any degree within the range
of the expansive power of the spring 15.
In Figures 3 and 4, wherein the sharpening stone 4 is shown applied to the front
side of the rotary knife C, the parts constituting the sharpening device have the
same functions as those shown in Figures 1 and 2, and the difference in the two
constructions lies only in certain apparent changes in the shape and location of
the parts necessitated by the reversed position of the stone 4 relative to the knife,
and in using a slightly different construction of a fastening device.
There is no particular advantage in the fastening device shown in Figures 1
and 2 over that shown in Figure 3, and vice versa, but that shown in Figures 1
and 2 is preferred because it is better adapted to be applied to brace-rods of varying
diameters than is the device shown in Figure 3.
In Figure 3, the arm 8 of Figures 1 and 2 is shortened up, the location of the
adjusting screw 9 is different, and the spring 15 is placed on the adjusting screw
instead of directly between the casting E and the support 2.
The spring might just as well be located between said support and said casting
at the point a, where it would have the same action as in the location shown on the
adjusting screw.
In the construction shown in Figure 4, a screw-operated fastening device is
illustrated, adapted to secure the sharpening device to a lawn-mower constructed
without the usual brace-rod D), and this construction consists in casting two
lugs 17, on the frame, the inner parallel faces of said lugs being undercut, as
shown, for the reception of a casting having a V-shaped base 18, a screw passing
through said casting against said frame serving to secure it in any desired position
relative thereto. The said casting is thus seen to be but another form of the cast-
ing E, shown in Figures 1 and 2, and the support 2 in the form shown in Figure 3,
is pivotally secured to said casting, as shown.
:
Said modifications above described thus resolve themselves into mere variations
in form only of the construction shown in Figures 1 and 2, and as such.come
legitimately within the scope of this invention.
It is obvious, also, that should one of the supports 2 be made of such form as to
embrace enough of the stone 4 to afford it sufficiently rigid support, that on the
smaller sizes of lawn-mowers one fastening device and one support could be used

page_text: instead of two, if desired, but the better construction is that shown in said
Figures 1 and 2. Furthermore, it is obvious that by the use of a stone of suffi-
cient weight, together with the weight of the supports 2, 2, that in the construc-
tion shown in Figure 1, the springs 15 might be dispensed with without destroying
the efficiency of the sharpening device, as the weight of said stone and supports
might be made sufficient to produce the desired abrading effect between the stone
and the rotary knife. As much or as little of the weight of the stone could be
allowed to rest upon the stone as might be desirable, by the manipulation of the
adjusting screws 9. Thus the weight of the stone and its supports might be made
to perform the functions of the said springs 15, and while the construction shown
in said Figure 1 is the preferred one, the above described construction would
still be within the scope of this invention.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. In combination with the frame of a lawn-mower, a sharpening device for the
rotary knife thereof consisting of the supports 2, 2, a screw-operated fastening
device for engagement with the frame of the machine, said supports and said
fastening device being pivotally united; adjusting screws engaging said fastening
device and said supports for moving the latter, whereby more or less of the weight
of the sharpening stone and its said supports may be allowed to bear upon said
rotary knife, substantially as described.
2. In combination with the frame of a lawn mower, a sharpening device for
the rotary knife thereof, consisting of the supports 2, 2, a screw-operated fastening
device for engagement with the frame of the machine, said supports and said
fastening device being pivotally united; adjusting screws engaging said fastening
device and said supports for moving the latter, and springs against the tension
of which said supports are moved in one direction by said adjusting screws, sub-
stantially as described.
3. In combination with the frame of a lawn mower, a sharpening device for
the rotary knife thereof consisting of a support 2, a screw-operated fastening device
for engagement with the frame of the machine, said support being pivotally secured
to the said fastening device, an adjusting screw engaging said fastening device and
bearing on said support at one side of the pivotal point thereof, and a spring
bearing on said support at the other side of said pivotal point thereof, whereby
said support is held in contact with said adjusting screw, substantially as set
forth.
DAL:
1
1
1000
WILLARD PHELPS LESHURE.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.