US2118199A - Sharpener and device for honing lawn mowers - Google Patents

Description

. May 24, 1938. F, HE LY 2,118,199

SHARPENER AND DEVICE FOR HONING LAWN MOWERS Filed July 1, 1955 llllllli ll Patented May 24, 1938 UNITED STATES Z,ll8,199

PATENT OFFICE SHARPENER AND DEVICE FOR HONING LAWN MOWERS 2 Claims.

My invention relates to improvements in automatic devices for, first sharpening, and secondly, honing the rotating blades also the stationary cutting blade of any standard lawn mower utilizing the driving power necessary to propel said lawn mower simultaneously with the cutting of the grass.

My invention consists of a metal abrasive adapter or form, adjustable to variable lengths, around which an abrasive element is positioned, and two adjustable, self-aligning brackets designed to fasten the device on the stationary, horizontal bar of any ordinary lawn mower, thus holding the abrasive in contact with the rotating blades of said lawn mower constructed and arranged all as hereinafter more particularly described and illustrated in the accompanying drawing in which,

Fig. 1 is a vertical cross-sectional view of a lawn mower showing my device positioned thereon; Fig. 2 a view of adjustable abrasive adapter; Fig. 3 a cross-sectional perspective end view of the assembly showing the end of adjustable abrasive adapter with abrasive element positioned around it and one of the adjustable self-align ing brackets, of which two are used, positioned on the stationary horizontal bar of a lawn mower and secured to adjustable abrasive adapter, with the assembly in its relative position to said horizontal stationary bar and one of the rotating blades of the lawn mower; and Fig. 4 a crosssectional end view of abrasive element.

Like characters of reference indicate corresponding parts in the diiferent views.

The adjustable abrasive adapter I shown in Fig. 2 consists of three thin metal sections 2, 3 and 4 of flattened annular cross-section concave on their outer wide surfaces with longitudinal edges 5 turned over opposite concave surfaces to leave sufiicient clearance 5 to accommodate one end each of sections 2 and 4 slid or telescoped within section 3 which is slightly larger for that purpose, also clearance to accommodate longitudinal edge of abrasive element I. Thus abrasive adapter I may be shortened or lengthened to fit the blade of a lawn mower of any standard width.

Adjustable self-aligning bracket depicted in Fig. 3, of which two are used, comprises metal clamp 8 drilled and threaded at top to accommodate screw 9 passing through helical spring II] and drilled and tapped through one side to accommodate set-screw II; and narrow strip of thin metal I2 having a series of holes or orifices I3 through it extending from outer upper end and plain at the other, bent in such manner that when abrasive adapter I is positioned thereon and the device is in an operative position, abrasive element I will be held at right angles across rotating blades I4 of lawn mower, proper tension 5 being exerted by helical springs I I).

The abrasive element shown in Fig. 4 is made of ordinary abrasive cloth or paper or other abrasive material so formed or moulded in shape with abrasive side outward as will allow it to be posi- 10 tioned around the abrasive adapter I. It is more or less flexible and of sufiicient length to allow it being shortened to any determined length and can be replaced at will after becoming worn.

In using my device, abrasive adapter I is first 5 adjusted to the desired length by means of sliding sections 2 and 4 within opposite ends of section 3, abrasive element I is then cut to the exact length of adjusted abrasive adapter I and corner I6 of abrasive element I pushed endwise and through groove 6 of abrasive adapter I until both ends of abrasive element I and abrasive adapter I coincide. Corner I! of abrasive element I is then brought down and pressed into groove 6 of abrasive adapter I and the horizontal edge of abrasive element I also forced into groove 6 throughout its entire length. Thus abrasive element I is positioned securely around abrasive adapter I with the abrasive side outward over the curved portion of abrasive adapter I and with abrasive surfaces pressed together along and within groove 6 of abrasive adapter I thereby further securing same. Plain ends of narrow strip I2 of adjustable self-aligning brackets, of which one is depicted in Fig. 3, are then forced between the two longitudinal edges of abrasive element I within groove 6 of abrasive adapter I and near opposite ends of same, metal clamp 8 fastened to stationary horizontal bar I5 of the lawn mower by means of set-screws II, screws 9 passing through helical springs I0 and screwed to metal clamps 8, through whichever one of the holes or orifices I3 will allow the central lower portion of abrasive element I to contact rotating blades I4 of lawn mower.

Thus when the lawn mower is in motion the abrasive element I is held lightly against rotating blades I4 of lawn mower, proper tension being maintained by helical springs I0, and by reason of the lower fiat portion of abrasive element I being held slightly away from abrasive adapter I because of the concave surface of the latter a slight upward movement of abrasive element I is permitted, thus maintaining an even cutting or abrasive action across the entire cutting edge of rotating blades [4 which tends to remove any uneven surfaces. When the lawn mower is being operated its rotating blades contacting with the abrasive are not only sharpened by such action but remove, at the same time, particles of the said abrasive and carry them around to contact the lower or stationary blade which is also simultaneously sharpened by the action of said particles of abrasive forced between the rotating blades and the stationary blade, this action also tending to properly align the rotating blades with the stationary blade; and, operating while the grass is being cut, particles of the grass are worked into the abrasive tending to smoothen its surface, thus constituting a honing process which removes any rough surfaces left from the original abrasive action. Thus the device first sharpens and secondly bones the cutting edges of the rotating blades and also the cutting edge of the lower, or stationary blade, the latter being accomplished by particles of grass and abrasive together passing between the rotating blades and the stationary blade.

The device as above described is extremely simple in construction, may be cheaply manufac tured in one standard design, readily applied to any ordinary construction of lawn mowers regardless of their width and will effectively perform the function for which it is devised.

I claim: 7 V

1. A shapener for mower blades comprising a metal body consisting of a pluralityof inter-fitting telescoping sections for adjustment to a predetermined length, said sections being relatively fiat plates with overturned edges and a flexible abrasive element shaped to enclose said metal body and adapted to be retained thereon by friction means.

2. In a sharpener for lawn mower blades a horizontal sectional metal body comprising three sections telescoping one within the other forming means for adjustment to predetermined length, each section consisting of a plate with its edges bent over forming a body of flattened crosssection concave on its outer wide surface and having its longitudinal edges in horizontal rela tion to each other but not meeting, a flexible abrasive element having its abrasive side outward shaped to enclose said metal body adapted to be retained by friction means for securing thereto,

two narrow metal strips having a series of orifices along their upper outward ends and plain at their lower ends said lower ends providing fric: tion means for attaching the abrasive element positioned around the aforesaid body, and two clamps each having a screw in its upper side passing through a helical spring providing means for attaching the aforesaid metal strips through any determined orifice therein to a support on the mower body. V V H V FRANK HEALY;

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