US1150931A

US1150931A - Lawn-mower.

Info

Publication number: US1150931A
Application number: US84411114A
Authority: US
Inventors: William Herbert Coldwell
Original assignee: Individual
Current assignee: Individual
Priority date: 1914-06-10
Filing date: 1914-06-10
Publication date: 1915-08-24
Anticipated expiration: 1932-08-24

Description

W. H. COLDWELL.

LAWN MOWER.

APPLICATION man :uuuo. 1914.

Patented Aug. 24, 1915.

2 SHEETS-SHEET I.

W. H. COLDWELL.

LAWN MOWER.

APPLICATION FILED JUNE 10,4914.

1 1 5@,931 n Patented Aug. 24, 1915.

2 SHEETSSHEET 2.

WILLIAM HERBERT COLDWELL, 0F NEWIBURGH, NEW YORK.

LAWN-MOWER.

Specification of Letters Patent.

Application filed June 10, 1914. Serial No. 844,111.

To all whom it may concern Be it known that I, WILLIAM H. ConnwELL, a citizen of the United States, residing at Newburgh, in the county of Orange and State of New York, have invented certain new and useful Improvements in Lawn- Mowers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention consists in the novel features hereinafter described, reference being had to the accompanying drawings which illustrate one embodiment of my invention and several slight modifications thereof, selected by me for the purpose of illustration, and the said invention is fully disclosed in the following description and claims.

Referring to the said drawings, Figure 1 represents a hand lawn mower embodying my present invention, a portion of the machine being shown in section. Fig. 2 is a. vertical transverse sectional view on line 2-2 of Fig. 1. through the stationary knife bar. Fig. 3 is a perspective view partly broken away of a bar from which the stationary knife is made. Fig. 4 is an end view of the knife proper after it has been fitted to engage the demountable supporting end blocks. Fig. 5 represents one form of demountable supporting end block, the relative position of the knife thereto being indicated in dotted lines. Fig. 6 is a detail view of another form of demountable end block in connection with the adjusting mechanism therefor, the position of the knife with respect to the end block being indicated in dotted lines. Fig. 7 is a view of a, still different form of end block which I find it advantageous to use where the sta tionary knife is to be rigidly and permanently mounted in the frame and the rotary cutter is to be adjusted with respect thereto, the position of the knife being indicated in dotted lines. Fig. 8 represents an end view of a slightly modified form of knife provided with two cutting edges. Fig. 9 is a front elevation of a form of stationary knife bar and detachable knife now in use showing in a slightly exaggerated manner the objectionable features thereof in the manufacture of lawn mowers of various kinds.

It is customary to form the so called stationary knife, which is supported in the frame below the rotary cutter or wiper, by

providing a heavy supporting knife bar, which is attached to the side frames or other supports at its ends and is provided with a separate knife or blade having a cutting edge of high grade tempered steel, which is secured to the knife bar usually by means of screws or rivets. It will be understood that as the cutting action of a lawn mower is a shearing action effected by the movement of the cutting edges of the spiral cutting blades of the rotary cutter or wiper across the edge of the stationary cutting knife like the action of a pair of scissor blades, it is absolutely necessary that the cutting edges of the blades of the rotary cutter shall be in exact relation, practically a rubbing relation with the cutting edge of the stationary .knife throughout the entire extent of both. This necessity. constitutes one of the prime difiiculties, and a considerable item of expense in the manufacture of lawn mowers. In my own practical experience as a manufacturer of lawn mowers extending over many years, I have found that in attaching a blade or knife to the supporting bar as before described, a slight buckling of the blade will invariably result. Even though it may be so slight in some cases as to be imperceptible to the eye, the attaching screws or rivets will nevertheless exert such unequal tension upon the knife blade that its projecting cutting edge will have a waving contour as indicated in Fig. 9 of the accompanying drawings. When the lawn mower is assembled and the rotary cutter is placed in operative position with respect to the stationary knife bar, it is always necessary to manually fit the rotary cutter and the knife bar to each other throughout the entire extent of each of the cutting blades to accommodate the inaccuracies in the cutting edge of the stationary knife. This requires skilled labor of a very high degree and in the practical manufacture of lawn mowers, it is usually necessary to accurately file or grind away portions of each of the blades of the rotary cutter in order to give them a shear out throughout their length against the cutting edge of the stationary knife. This adds greatly to the cost of manufacture and is one of the most expensive operations, being the one which requires the greatest amount of skilled labor. Even after the mower has been carefully fitted and adjusted in the manner described the steel cutting blade is under a certain amount of strain due to its Patented Aug. 24, 1915.

attaching devices and changes of temperature, or the blows which the knife bar receives in passing over obstacles, and which have a tendency to slightly spring the knife,

.machine so as to permit the rotary cutter to accurately engage the same without any hand fitting whatever so that this expensive item for hand labor in the manufacture of a mower is absolutely dispensed with, and at the same time a greater degree of accuracy of the cutting mechanism itselfis secured and maintained.

In carrying out my invention I form a heavy bar 1, of a section such as indicated in Fig. 3, which can be rolled or otherwise formed in suitable lengths and serves as the knife and bar combined. It is not necessary that the entire bar be formed of high grade steel as only a small portion adjacent to the cutting edge 2 need be tempered and a portion of steel suitable for a cutting edge can be readily rolled into the bar at the time of making the same in the Well lmown way. To make a knife, I cut off a section of this bar of the required length and provide it at each end with demountable supporting end blocks which are secured to the knife 1. I find it convenient to provide the knife proper at each end with apertures 3-3 to receive guide ins or dowels 4-4 on the inner face of t e end block 5 (see Figs. 4 and 5), and the end block can be conveniently secured to the knife by means of a screw 6 (see Fig. 2), which extends through an aperture 7 1n the block 5 and'engages a threaded aperture 8 in the knife 1. I do not limit myself to this particular means for connecting the and blocks to the knife, but I find these means advantageous and eifective. For example, after cutting off the bar, as shown in Fig. 3, of the required length, the guiding apertures 33 and aperture 8 may e formed accurately in each end by a suitable jig so as to have always the same relation to the edge portion of the knife and using the idmg apertures 3-3 as fixed cutting e ge, the bars can be ground so that the cutting edge 2 will always be in exact relation thereto, as will be clearly understood by any one skilled in the art. When the supportin end blocks 5 have been connected to the 'fe 1, the lmife is inserted in the mower frame and secured therein, for example, by means of screws 99 (see Fig.

2) extending through apertures 10 in the oints by w 'ch to determine the end blocks. The I the shaft of-tlie rotary cutter, throughout at 11 in r -made-in the usu am1 3- the length of the spiral blades. It therefore follows with this construction that the edge 2 of the stationary knife, when the latter 1s placed in the frame in proper position, W111 be absolutely true with respect to the cutting edges of the rotary knife, as the proper relations between the dowel and the supporting aperture 10 of the end" blocks" and the proper relation of thehole in the side frames through which'the screws 9 pass can be obtained with the utmost accuracy by means of suitable 'jigs, so that the parts can be assembled, and it is only necessary to adjust the cutting edges of the stationary knife and the-rotary cutter toward and from each other to secure an absolute shear but from one end to the other, and it is not necessary to resort to any hand labor whatever in fitting the parts. The adjustment of the stationary and rotary cutters with respect to each other may be conveniently accom lished by rocking the demountable end bloc upon their supporting screws 9, as shown in Fi 1, by means of'adjusti-ng screws 12 an 13 passing through lugs 14 and 15 respectively on the sideframes, the adjustment being obtained in either direction by bacln'ng off one of said set screws and screwing up the other one.

Different forms of adjusting mechanism for the cutting mechanism are employed in different kinds of lawn mowers and frequently several different kinds of adjustparticularly advantageousporting blocks which the particular style of adjustment or particular type of lawn mower requires. Thus, for example in Fig. 6, I have showna different style of, .end-

block 5, provided with the dowel pins Y t -4, screw aperture '7, and pivotal aperture 10, the end block being provided with" a short arm 16 adapted to be engaged by adjusting screws 12% and -13*on,opposite sides, for holding thefend block in position and adjustingit. v x

In Fig;,7 have ,s'hown a different style of and lock 5!, whichv is provided with dowel pins 4", screw aperture 5 7 and the i a erture 10 to rece ve-the retaining screw.

is form of end blocks is sirable when the stationary f fe is rigidly pglliticularly do I I secured to the frame,- in which case the r01 tary cutter is adjusted toward and from:

the stationary knife in a'wellknown way,

which I need 'not herein; v trate or describe, t f 1 end, I have ecificallyi illus- 1 1 50,93 1 i it? shown the end block 5 provided with a dowel pin 17 adapted to engage a suitable aperture in the side frame to prevent rotation of the end block upon the retaining screw which passes through the aperture so that with a single screw, the. block can be rigidly clamped to the side frame.

In some instances, I may form the bar 1 with a cutting edge at both sides, and this construction I have shown in Fig. 8 at 1, the cutting edges being indicated at 2*, said bar being provided with apertures 3 to receive the dowel pins in the demountable end blocks, and with a threaded aperture 8 to receive the retaining screws for connecting the end blocks thereto.

' It will be seen that by forming the stationary knife and supporting it in the manner described, the same bar stock can be used for every width mower, and for hand mowers, horse mowers, and motor mowers, as desired, and that the same bar can be used with the required demountable end blocks for any particular style mower or for any particular type of adjustment which may be necessitated in the particular style. My invention therefore greatly facilitates the manufacture and assembling of the stationary knife bars and entirely dispenses with the costly and tedious hand labor of fitting the stationary and rotary cutters, and produces a machine in which the stationary knife and rotary cutter as made and as assembled in the machine, must of necessity be exactly accurate, requiring only the simplest form of hand adjustment to bring them into proper cutting relation. My invention will also obviate the necessity which now frequently occurs of returning mowers to the factory for re-adjustment of the cutting mechanism, as any owner of a lawn mower can make the simple hand adjustment necessary to bring the parts of the cutting mechanism closer together in case of wear, with out danger of throwing the cutting mechanism out of operative relation.

In Fig. 1 of the drawing 20 represents the side frames of the mower in which the rotary cutter 11 and stationary knife 1 are mounted, suitable gearing being provided for driving the rotary cutter, in this instance from the ground wheels 22, and the mower frame is provided with a rear ground roller 23 and with a suitable handle 24, a portion of which is broken away, by which it may be pushed over the ground. The particular details of these parts of the mower construction form no part of my present invention, and it is obvious, that, as before stated, my invention is applicable to any style of lawn mower having a rotary cutter for any style of these various kinds of mowers and made to cooperate with the particular form of adjustment employed therein without any variation in the other features of the mower.

What I claim and desire to secure by Letters Patent is I 1. In a lawn mower, the combination with a main frame for supporting the cutting mechanism, a rotary cutter mount-ed therein having the cutting edges of its blades lying in a cylindrical plane having its axis coincident with the axis of rotation of the rotary cutter, of a stationary knife bar consisting of a piece of straight wrought metal stock provided with an integral longitudinally extending cutting edge, a pair of demountable supporting end blocks for said knife bar, each provided with means for securing it to the supporting frame for the cutting mechanism, and means for securing the said knife bar to said end blocks, having an exact predetermined relation with the cutting edge of the knife and the means for securing the end blocks to the said frame, so as to maintain the cutting edge at all times in exact parallelism throughout its length with the cylindrical plane of the cutting edges of the rotary cutter blades, and means for securing the adjustment of said rotary cutter and stationary knife the one toward and from the other, whereby the rotary cutter and stationary knife may be brought into shearing relation throughout the length of their cutting edges without hand fitting.

2. In a lawn mower, the combination with opposed vertically disposed frame plates for supporting the cutting mechanism thereof, of a stationary knife bar having an integral cutting edge, a demountable supporting end block at each end of said knife bar engaging the end face of said bar, said end block having its opposed face engaging the inner face of the adjacent frame plate, means for attaching each of said end blocks rigidly to the adjacent frame plate, and devlces extending longitudinally of the knife bar for connecting it with each of said end blocks.

3. In a lawn mower, the combination with opposed vertically disposed frame plates for supporting the cutting mechanism thereof, a rotary cutter mounted in said plates, a stationary knife bar provided with an integral cutting edge to cooperate with the rotary cutter, demountable supporting end blocks having their inner faces engaging the end faces of said knife bar and their outer faces engaging the inner faces of said frame plates, means for securing each of said end blocks to the adjacent frame plate, adjusting devices on each of said frame plates engaging the adjacent end block, and devices disposed longitudinally of the knife bar extending through each of said end blocks and engaging the lmife bar for ri 'dly securing the knife and end-blockstogeger.

4. In a lawn mower, the combination with vertically disposed frame plates for supporting the cuttin mechanism thereof, of a stationary knife ar provided with an integral cutting edge, demountable supporting end blocks engaging the end faces of said bar, means for securing said end blocks to said frame plates, and means for securing the knife bar to said end blocks extending longitudinally of the knife bar, said knife bar and end blocks being provided with interlocking devices extending longitudinally of the lmife bar for assisting in holding the knife and blocks in fixed relation.

5. A stationary lmife for lawn mowers comprising an integral bar and demountable supporting end blocks engaging. the end faces of said bar, said knife bar and blocks being provided the one with projections and the other with recesses extending longitudinally of the bar and forming interlocking portions, said interlocking portions having a predetermined relation to the cutting edge of the knife, and means extending longitudinally of the bar for securing the knife bar and end blocks against accidental displacement.

6. A stationary knife for lawn mowers comprising an integral bar and demountable supporting e d blocks engaging the end faces of the ar, said blocks and bar being provided the one with a pair of dowels extending longitudinally of the bar, and the other with recesses to receive said dowels, and forming interlocking portions, the interlocking portions of the knife 'bar having a predetermined relation with the cutting edge, and attaching screws disposed longitudinally of the bar and extending through the end blocks and into the bar, for holding said bar and end blocks in assembled relation. 7

7. In a lawn mower, the combination with a main frame for supporting the cutting mechanism, a rotary cutter mounted therein having the cutting edges of its blades lying in a cylindrical plane, having ltS axis coincident with the axis of rotation of the rotary cutter, of a stationary knife bar consisting of,

to the supporting frame for the cutting mechanism, said knife bar and said blocks being provided with interlocking means for accurately positioning said end blocks with respect to the cutting edge of the lmife bar,

and means independent of said interlocking. means for securing said end blocks rigidly to the knife bar so as to maintain the cutting edge at all times parallel to the axis of the rotary cutter, and means for adjusting the rotary cutter and knife bar one toward and from the other, whereby the rotary cutter and knife bar may be brought into shearing relation throughout the length of their cutting edges without hand fitting.

8. In a lawn mower, the combination with the supporting frame plates for the cutting mechanism thereof, of a stationary lmife bar, a demountable end block engaging each of the end faces of said bar, securing devices connecting each end block with the bar, extending through the end blocks and disposed longitudinally of the bar, the extenor faces of said end blocks engaging the said frame lates, for su portin the cut P g g ting mechanism, and there y preventing the securing devices from working loose, and means for rigidly securing each of said end blocks to the adjacent frame plate.

In testimony whereofI aflix my signature, in the presence of two witnesses.

WILLIAM HERBERT GOLDWELL.

Witnesses:

Enwm T. Smrrn, HENRY Wmniv Mnnrrnnn'r.