US1850624A

US1850624A - Grinding attachment for lawn-mowers

Info

Publication number: US1850624A
Application number: US511665A
Authority: US
Inventors: Sr Lawrence G Haines
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-01-28
Filing date: 1931-01-28
Publication date: 1932-03-22
Anticipated expiration: 1949-03-22

Description

March G. HAINES, SR

GRINDING ATTACHMENT FOR LAWN MOWERS Filed Jan. 28, 1931 "'llllmlllli ATTORNEY Patented iMar. 22 1932 UNITED STATES PATENT OFFICE LAWRENCE G. HAIN'IES, SR., 01 GLASSBORO, NEW JERSEY GRINDING ATTACHMENT FOR LAWN-MOWERS.

Application filed ma 28,1931. Serial No. 511,665. 1

. This. invention relates to sharpening de-' vlces for lawn mowers and analogous machines and has more especial relation to improvements upon the grinding attachment disclosed in myPatent No. 893,164, issued July14, 1908.

While the structure disclosed in my aforesaid patent has in practice given excellent results, long and continued use thereof has lo'demonstrated the need of certain additions point of maximum efficiency.

and changes to enhance its usefulness to the As an example, the angular, resllient plate supporting the abrading material in use has loose.

the tendency to buckle intermediate its length so that in rotation of the mower blades true contact is not always present. Again,

practice dictates that the angular brackets supporting thearcuate arms frequently jar Further, these arcuate arms because of their open ends permitdislodgment of the butterfly nuts employed in connection therewith. -;Still further, removal when desired of theabrading carrying element is not as convenient as maybe.

" The leading object of the present invention, therefore, may be said tobe the overcoming of these objectionable features and to provide an arrangement, connectlon, and

combination of'parts for enhancing the com mercial valueof the grinding attachmen embodying the invention. I

With this and other objects in view, the invention consists of the novel construction hereinafter described and finally claimed.

The nature, characteristic features and scope of the invention will. be more fully understood from the following description taken, in connection'with the accompanying drawings forming part hereof, and. in which:

a Fig. 1 is a cross sectional: view of a lawnmower having applied thereto the attachment embodying: the invention I Fig. Qisa-vievv in perspective of the attachment, embodying the nvention, de-

tached; V

Fig. ;3 is a fragmentary view 1n plan of certain of the parts shown in Fig. 2;

Fig. 4* is a view principally in cross-section of the attachment shown in Fig. 2

*that the various instrumentalities ofwhich my invention consists can. be variously arranged and organized and that my invention is not limited to the precise arrangement and organization of the instrumentatlities as herein shown and described. 7

Referring to the drawings in'detail, there is disclosed a lawn-mower having driving wheels 2, rotary blades 8, a l'Ollel'd, and a handle 5, all of which parts may be of any desired construction. Having adjustable relation with the frame 6 which supports the roller 4 are arcuate arms 7, slotted "as at 8 throughout the entire length of each arm. The ends of the arms, however, are closed at each end as indicated by the reference nu meral 9. These arms 7 after proper adjustment may be secured .to place and permitted tofremain upon the lawn-mower during functioningthereof. Arranged to be attached tow and detached from these arms 7 is arectangular sharpening device capable of adjustment with respecttothearms 7 in a manner to be hereinafter more particularly described.

The rectangular sharpening device comprises v a resilient metallic elongated plate 10 having extended upwardly therefrom at its rear the flange 11 to provide a relatively L-shaped is turned over upon itself to provide. a reinforcing rib 12. .The upper edge of the flange 'll'is turned over upon itself as at 13 to provide a reinforcing rib. Both the plate 10 and the flange 11 at their opposed ends are bent over upon themselves to provide reinstructurey The plate lOat its forward end forcing ribs 14. These reinforcing ribs'add strength and relative rigidity to the sharpening device. Fitted to the bottom of the plate 10 and over the rib 12 is a sheet of f abrading material 15,11sually of emery cloth.

In practice the abrading material is usually glued to the plate 10. Fitted to the rear of the flange 11 is a thin metal bar 16. This bar is secured centrally of the flange 11 by means of a screw 17 and a nut 18, see Fig. l.

7 At this point of attachment the screw 17 and nut 18 are utilized for securing in position a leaf spring 19, the free end of which is caused to engage beneath the reinforcing rib 12. The purpose of this leaf spring 19 is to insure relative rigidity of the plate 10, thus tending to maintain the plate 10 closely adjacent the blades 3 in their rotation. In order to provide additional stability to the plate 10, additional leaf springs 20 are provided one upon either side of the leaf spring 18, as best seen in Fig.2. Having slidable relation with respect to the bar 16 is a pair of oppositely disposed angular brackets 21, each slotted as at 22. The inner ends of each of these brackets is closed as at 24 and the opposite end of each of these brackets terminates in a forked open-ended portion 25. In practice screws 26 and nuts 28 are employed for securing the slotted brackets 21 with respect to the flanged portion of the plate 10. As plainly shown in Fig. 3, substantially U-shaped clamps 29 are fitted over the brackets 21 and the screws 26 caused to pass through these clamps and through the slotted portion of the brackets 21 and through both the flange 11 and the leaf s rings 20, whereby with the tightening of tile nuts 28 the angular brackets 21 may be secured in adjustable position. The function of the brackets 21 is that of accommodating securing of the attachment as a whole to various sizes of lawn-mowers. By this structure shown in my aforesaid patent, these brackets frequently became loose, and I have discovered that by employing the U-shaped clamps 29 this defect is overcome. In practice the brackets 21 may be permanently attached, if desired, to the arms 7 of the lawn-' mower by means of butter-fly nuts 30. However, to facilitate ready removal of the attachment as a whole from a lawn-mower, I havefound it convenient to leave the ends of the brackets 21 open as at 25 as before described, whereby it is merely necessary to unloosen the butter-fly nuts 30 and withdraw the brackets from the arms 21 without actuall removing the butter-fly nuts.

. The construction disclosed in Fig. 6 is similar in all respects to that previously described with the exception that the plate holding the abrading material is curved upon its underside as at 31.

The above described attachment is adjusted upon a lawn-mower when it is desired to sharpen the rotary blades and is so arranged that as the blades revolve in a backward or reverse movement to that ordinarily used in the cutting of grass, the heel of each knife comes in contact with the abrading surface of the attachment to effect a keen cutting edge for the blades. By reason of the special resilient features of the combined plate and leaf springs the blades of the lawn-mower contact with the abrading material with just suflicient pressure to effect efiicient shar ening without causing the cutting parts 0 the blades to be unduly worn. In practice it has been demonstrated that very good results may be obtained by sharpening the blades of a lawn-mower by revolvin I the blades backwardly, as fully set fort in my aforesaid patent.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

What I claim is:

1. A sharpening attachment for a lawnmower, comprising a relatively resilient plate carrying a sheet of abraiding material, said plate having a flange at its rear, the edges of said plate and flange both longitudinally and laterally considered being folded over to provide a reinforcement, a leaf spring secured 1 between the longitudinal reinforcement portions of said flange and plate at each end thereof, and a second leaf spring similarly secured intermediate said first mentioned leaf springs for relatively stiffening the central portion of said plate.

2. A sharpening attachment for a lawn mower, comprising a relatively resilient plate carrying a sheet of abrading material, said plate having a flange at its rear, the edges of.

said plate and flange both lon itudinally and laterally considered being fol ed over. to provide a reinforcement, a leaf spring secured between the longitudinal reinforcement portions-of said flange and thereof, and a second lea s ring similarly secured intermediate said rst mentioned leaf springs for relatively stiffening the'central ortion of said plate, and angular slotted brac rets adjustably mounted at each end of u said flange, the inner ends of said brackets being closed to said slots but having their outer ends open to said slots.

3. A sharpening attachment for a lawn mower, comprising a relatively resilient plate carrying a sheet of abrading material, said plate having a'fiange at its rear, the edges of said plate and flan e both longitudinally and laterally considere being folded overto provide a reinforcement, a leaf spring secured between the longitudinal reinforcement portions of saidflange and plate at each end thereof, a second leaf 5 ring similarly secured intermediate said rst mentioned leaf springs for relatively stiffening the central portion of said plate, and pairs of substanlate at each end.

tially U-shaped clamps for engaging over that portion of each of said brackets which parallels saidflange. c

4. A sharpening attachment for a lawn mower, comprising a relatively resilient plate carrying a sheet of abraiding material, said plate having a flange at its rear, the edges of said plate and flange both longitudinally and laterally considered being folded over to provide a reinforcement, a leaf spring secured betweenthe longitudinal reinforcement por- I tions of said flange and plate at each end thereof, a second leaf spring similarly secured intermediate said first mentioned leaf springs for relatively stiffening the central portion of said plate, and screws and bolts for securing said clamps to place, said'screws and bolts serving to secure at least some of said leaf springs to place.

5. A sharpening attachment for a lawnmower, comprising a relatively resilient plate I carrying a sheet of abrading material, said plate having a flange at its rear, the edges of said plate and flange both longitudinally and laterally considered being folded-over to provide a reinforcement, a leaf spring secured between the longitudinal reinforcement portions of said flange and plate at each end thereof, a second leaf spring similarly secured intermediate said first mentioned leaf springs for relatively stiflening the central portion of said plate, and an arcuate slotted arm carried by each of said brackets, both ends of each of said arms being closed to said slots. V

LAWRENCE Gr. HAINES, SR