Mower Blade Sharpening Angle Grinder Adaptor

Description

CLAIM OF PRIORITY FROM PREVIOUSLY FILED PROVISIONAL APPLICATION

This non-provisional patent application claims the benefit of and priority from U.S. Provisional Ser. No. 63/719,891 filed Nov. 13, 2024. The Inventor and Applicant disclosed in said provisional application is the same person who is disclosed as the Inventor and Applicant of the instant application. The Applicant asserts that structures and functions of structures disclosed and described in the instant application are substantially identical to those described in said provisional application.

FIELD OF THE INVENTION

This invention relates to electric motor driven or pneumatic motor driven angle grinders. More particularly this invention relates to adaptors attachable to such angle grinders which assist an operator in controlling grinding and cutting.

BACKGROUND OF THE INVENTION

Electric motor driven and pneumatic motor driven angle grinders are known to be used for grinding metal articles. Where an angle grinder is utilized for purposes of grinding a dulled mower blade for purposes of restoring the blade's beveled cutting edge, difficulties in maintaining a proper 30° to 40° cutting edge or bevel angle are often encountered. Also, during utilization of the angle grinder for mower blade grinding, the angle grinder operator often encounters further difficulties in maintaining a consistent grinding depth. Known methods and modes of use of angle grinders often produces a mower blade cutting edge which is undesirably uneven as a result of such grinding angle variations and grinding depth variations.

The instant inventive mower blade sharpening angle grinder adaptor solves or ameliorates the problems, defects, and deficiencies set forth above by providing a specialized blade supporting bracket which may universally attach to angle grinders manufactured by various power tool manufacturers. The inventive adaptor provides a correctly angled blade support table which may slidably guide a dulled mower blade beneath the rotating grinding surface of the angle grinder's grinding wheel.

BRIEF SUMMARY OF THE INVENTION

A first structural component of the instant inventive mower blade sharpening angle grinder adapter comprises an inverted “U” bracket having a proximal leg, a distal leg, and having a web spanning between upper ends of such legs. In a preferred embodiment, the adaptor's “U”bracket component is composed of durable steel.

A further structural component of the instant inventive adaptor comprises a table having a length sufficient to span horizontally between the “U” bracket's legs. Like the “U” bracket, the adaptor's table component is preferably composed of durable steel.

Further structural components of the instant inventive adaptor comprise table mounting means which are adapted for respectively attaching proximal and distal ends of the table to the “U” bracket's proximal and distal legs. In a preferred embodiment, the table mounting means are further adapted for extending the table at blade bevel matching angle, between 30° and 40° with respect to the “U” bracket's legs. In the preferred embodiment, the table mounting means are further adapted to facilitate selective positioning of the table at various elevations beneath the “U”bracket's web.

The adaptor's table mounting means may suitably comprise eye and travel slot combinations, wherein such combinations'eyes open at angled mounting tabs or flanges which extend from a rearward edge of the table. Such combinations'travel slots may suitably open at and extend vertically along the “U” bracket's legs. Upon front-to-rear alignments of such combination's eyes and slots, helically threaded bolt fasteners may be extended therethrough. Upon tightening of such bolt fasteners, the table may be securely held at a selected elevation beneath the web. Upon loosening of such bolt fasteners, the table may be selectively repositioned.

A further structural component of the instant inventive adaptor comprises an annular clamp having forward and rearward sections or segments. In a preferred embodiment, the annular clamp's forward section comprises a medial or central portion of the “U” bracket's web, the rearward segment of the annular clamp correspondingly comprising a flexible strap having a first end fixedly attached to the web.

Further structural components of the instant inventive adaptor comprise strap tightening means which are preferably operatively mounted upon the “U” bracket's web. In the preferred embodiment, the strap tightening means are adapted for engaging, pulling, and tightening the opposite end or second of the flexible strap. Such tightening means may suitably comprise an over-center latch. Upon engagement of the tightening means with the free or second end of the flexible strap, an angle grinder neck clamping space is advantageously formed.

In use of the instant inventive adaptor, an operator may forwardly extend a forward aspect of an angle grinder's grinding wheel beneath the adaptor's web and above the adaptor's table. Thereafter, the annular clamp's flexible strap component may be extended about lateral and rearward aspects of the angle grinder's neck. Thereafter, the operator may engage the opposite or second end of the flexible strap with the adaptor's strap tightening means. Where such means comprise an over-center latch, as is preferred, the operator may manipulate the latch's pull lever, thereby tightening the flexible strap about the angle grinder's neck, and securely fastening the adaptor to the angle grinder.

Thereafter, the operator may slidably move the table upwardly along the “U” bracket's legs until the table's upper and rearward edge parallels and immediately underlies the grinding wheel's lower asperous grinding surface. Upon such positioning, a “V” shaped grinding valley is advantageously formed, the angle of the “V” valley matching the desired bevel angle of a mower blade cutting edge. Thereafter, the adaptor's table mounting means may be manipulated to securely lock the table at such “V”valley forming position.

Thereafter, the operator may actuate the angle grinder, and may slidably move a dulled mower blade laterally over the table's upper surface. Such sliding motion advantageously coincides with rearward grinding contact by the bevel of the mower blade with the rotating asperous undersurface of the angle grinder's grinding wheel. Provided that the operator maintains the of the mower blade in flat and coplanar contact with table while distally sliding the blade along the table, accurate and consistent grinding of the cutting bevel of the mower blade is achieved.

Accordingly, objects of the instant invention include the provision of a mower blade sharpening angle grinder adaptor which incorporates structures as described above, and which arranges those structures in relation to each other in manners described above for the achievement of beneficial mower blade grinding and sharpening functions as described above.

Other and further objects, benefits, and advantages of the instant invention will become known to those skilled in the art upon review of the detailed description which follows, and upon review of the appended drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of the instant inventive mower blade sharpening angle grinder adaptor.

FIG. 2 is an alternative perspective view of the adaptor of FIG. 1.

FIG. 3 re-depicts the structure of FIG. 2, the view of FIG. 3 showing engagement of free end of a strap component to form an angle grinder neck clamping space.

FIG. 4 is a proximal side view of the structure of FIG. 1.

FIG. 5 re-depicts the structure of FIG. 4, the view of FIG. 5 showing a dulled mower blade in engagement with table and grinding wheel components of the instant invention.

FIG. 6 re-depicts the structure of FIG. 5, the view of FIG. 6 showing a completion of mower blade sharpening grinding.

FIG. 7 is an alternative frontal perspective view of the instant inventive adaptor, the view further showing attached angle grinder and grinder wheel components.

FIG. 8 re-depicts the structure of FIG. 7, the view of FIG. 8 showing a mower blade distally extended over an upper surface of an adaptor table component.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and in particular to FIG. 1, a preferred embodiment of the instant inventive mower blade sharpening angle grinder adaptor is referred to generally by reference arrow 1. The adaptor 1 preferably comprises a “U” bracket which incorporates a proximal leg 8, a distal leg 6, and a web 2 which spans between and rigidly interconnects upper ends of said legs. In a preferred embodiment, the “U” bracket 2,6,8 is composed of durable steel.

Travel slots 10 and 12 preferably extend into and through the “U” bracket's legs 6 and 8, and a strap receiving slot 4 preferably extends into and opens downwardly at the “U” bracket's web 2. Feet 15 and 17 preferably extend horizontally and rearwardly from the lower ends of the “U” bracket's legs 6 and 8, and permanent magnets 16 and 18 may be suitably fixedly attached to lower surfaces of the “U” bracket's feet 15 and 17. The magnets 16 and 18 may advantageously stabilize the adaptor 1 during use upon a steel topped work bench. Elastomeric friction pads (not shown within views) may be suitably substituted for magnets 16 and 18.

A steel mower blade supporting and guiding table 20 is provided in combination with table mounting means which securely mount proximal and distal ends of the table 20 upon the “U” bracket's proximal and distal legs 8 and 6. In the preferred embodiment, the table mounting means are adapted for vertically adjustably mounting the table 20 upon the “U”bracket's legs 6 and 8.

Referring simultaneously to FIGS. 1, 2, and 4, the table mounting means may suitably comprise proximal and distal eye and travel slot combinations. Referring in particular to FIG. 4, mounting flange apertures or eyes 33 are represented by dashed lines drawn upon the table's proximal mounting tab 24, such aperture 33 constituting the eye component of the adaptor's proximal eye and travel slot combination. A similarly configured eye (not shown within views) extends through the table's distal mounting tab 22. The adaptor's eye components 33 may align with and may respectively forwardly overlie the legs'proximal and distal travel slot components 12 and 10, thereby completing the adaptor's proximal and distal eye and travel slot combinations.

The adaptor's table mounting means preferably further comprise proximal and distal bolt fasteners 32 and 28 which may be respectively extend rearwardly through the eyes 33 which open at mounting flanges 24 and 22. Such fasteners 32 and 28 respectively further extend rearwardly through the immediately rearwardly underlying travel slots 12 and 10. Wing nuts 34 and 30 may be threadedly mounted over the rearward helically threaded ends of the fasteners 32 and 28, and such nuts may be tightened against the rearward faces of the “U” bracket's legs 8 and 6. Tightening of the wing nuts 34 and 30 advantageously secures the table 20 at a selected elevation beneath the “U” bracket's web 20, and loosening of such nuts allows selective repositioning of the table.

Referring simultaneously to FIG. 1-6, the instant inventive adaptor 1 preferably further comprises a grinder neck encircling member, suitably a flexible strap 36 which has a high tensile strength and is capable of exerting a high pulling force against a circular structure such as the perpendicularly extending neck 74 of a hand operated angle grinder 70. The angle grinder 70 has a perpendicularly extending neck 74 which houses and rotatably supports a rotary output shaft 76 having a lower helically threaded end 79. A circular grinding disc or cutting wheel 78 is mounted over the rotary output shaft 76, and such disc is secured thereon by an internally helically threaded nut 82.

In the depicted embodiment, the flexible strap 36 functions as a rearward segment or section of an annular clamp, the medial portion 3 of the “U” bracket's web 2 advantageously constituting and functioning as such clamp's forward section. A first end 37 of the annular clamp's strap 36 is fixedly attached to a rearward surface of the “U” bracket's web 2 by means of an “L” bracket 38 which is attached by bolts or rivets 40 and 42. The opposite end or free end 39 of the strap 36 presents a second “L” bracket 46 which functions as a hook flange, such hook flange 46 being securely attached to the strap 36 by means of bolts or rivets 48.

As shown in FIG. 3, the free end 39 of the strap 36 may be extended forwardly through the opening or gap 14 beneath the web 2 and above the table 20. Thereafter, the upper edge of the strap 36 may be extended upwardly into slot 4. Upon such engagement of the strap 36 within the slot 4 an annular clamping space 35 is advantageously formed.

The instant inventive adaptor 1 further incorporates tightening means which may engage the hook 46 and which may forcefully draw the free end 39 of the strap 36 forwardly through the slot 4, thereby constricting the annular clamping space 35. In a suitable embodiment, as depicted, the tightening means may comprise an over-center latch assembly 55 which includes a base plate 60 mounted upon the forward face of the web 2 by bolts or rivets 62, upper and lower clevis ears 58 wholly formed with and extending forwardly from upper and lower edges of the base plate 60, a “U” configured lever 56 pivotally mounted upon the clevis ears 58, an internally helically threaded nut 54 spanning between and rotatably mounted upon the open and lower arms of the “U” configured lever 56, and a loop 50 and threaded shaft 52 combination threadedly engaging the nut 54.

Upon engagement of the loop 50 of the over-center latch assembly 55 with hook 46 as depicted in FIG. 3, the lever 56 may be pivoted from the proximally retracted position depicted in FIG. 3 to a distally extended position as depicted in FIG. 7. Upon full distal extension of the lever 56 to the FIG. 7 position, the strap 36 is forcefully drawn forwardly through slot 4 and clamping space 35 is simultaneously forcefully constricted. Also upon such distal extension of lever 56, the pivot axis 53 of the helically threaded nut 54 is advantageously displaced rearwardly from the ears'pivot axis 57. While the lever 56 occupies its distal position, proximally directed pulling forces applied by the helically threaded shaft 52 to the rotatable nut 54 tend to further distally pivot the lever 56 toward the base 60, advantageously locking the lever 56 at its fully distally pivoted position. Accordingly, full distal pivoting of the lever 56 locks the strap 36 at an annulus constricting position.

Referring simultaneously to FIGS. 3 and 4, the angle grinder's neck 74 may have varying diameter depending on the make and model of the tool. Where a provided angle grinder neck 74 has a relatively small diameter, the effective length of the threaded shaft 52 may be reduced by rotatably screwing the shaft 52 distally through nut 54, thereby constricting the clamping space 35. Alternatively, to accommodate annular clamping about a larger diameter angle grinder neck, the loop 50 and threaded shaft 52 may be proximally unscrewed, correspondingly increasing the size of the clamping space 35.

In a suitable alternative embodiment, the clamping grinder neck encircling member may comprise a hingedly opening “C” configured ring (not depicted within views), such ring having a forward section which is fixedly attached to the “U” bracket's web, and has a rearward section which curves and extends around the rearward aspect of the angle grinder's neck. In such suitable embodiment a tightenable and releasable fastener, such as an over-center latch may span between ends of such hinged “C” configured ring, such fastener effectively annularly clamping holding the grinder's neck at the rearward side of the web.

Referring simultaneously to all figures, in use of the suitable embodiment 1 of the instant inventive adaptor, an operator may initially loosen wing nuts 30 and 34 and may temporarily slidably move the table 20 downwardly to a grinder installation facilitating position, such table height adjustment temporarily increasing the size of the adaptor's grinder wheel passage space 14.

Thereafter, the forward aspect or end of the grinding wheel 78 of the angle grinder 70 may be extended forwardly through space 14, and the strap 36 may be extended about the neck 74 of the angle grinder 70. Thereafter, the upper edge of the free end 39 of the strap 36 may be extended upwardly into slot 4, and the loop 50 of the over-center latch assembly 55 may be engaged with the strap's free end hook 46.

Thereafter, the operator may forcefully pivot the lever 56 distally from the FIG. 3 position to the FIG. 9 position. Such lever pivoting constricts the clamping space 35, forcefully driving the strap 36 radially inwardly toward the rotation axis of the neck 74, and forcefully driving the rearward face of the web 2 against the front surface of the neck 74. Such over-center latch driven web and strap tightening of the annular clamp 2,3,36 about the angle grinder's neck 74 securely fastens the adaptor 1 to the angle grinder 70.

Thereafter, the operator may slidably move the table 20 upwardly along travel slots 10 and 12 until the upper and rearward edge of the table 20 immediately underlies and parallel's the asperous grinding surface 80 of the grinding wheel 78. Thereafter, wingnuts 30 and 34 may be tightened, securing the table 20 in place.

Thereafter, the adapter 1 may be placed upon a level surface such as a top of a work bench. Where the work bench has a steel surface, the preferably provided permanent magnets 16 and 18 extending downwardly from feet 15 and 17, advantageously magnetically stabilize the adapter 1. Thereafter, the operator may actuate the angle grinder 70 while holding the angle grinder's rear hand grip (not shown within views) with one of his or her hands. The operator may utilize his or her other hand to place a mower blade 90 having a dulled cutting edge 92d upon the upper surface of the table 20.

Thereafter, the operator may use such other hand to drive such dulled cutting edge 92d rearwardly into the “V” cleft or valley, formed by the table 20 and the grinder wheel 78. Simultaneously with such rearward driving of the blade 90, the operator may slidably move the blade 90 distally beneath such wheel. Repetitions of such actions advantageously produces a sharpened edge 92s within blade 90, as indicated in FIG. 6.

The bevel angle of the blade's sharpened edge 92s substantially matches the angle between the forward extension of the grinder wheel 78 and the table 20. The adaptor's annular clamp 2,3,36 will typically hold the adaptor 1 upon an angle grinder 70 to form an approximate 90 degree or perpendicular extension of the grinder wheel 78 with respect to the “U” bracket's legs 6 and 8. With such perpendicular extension of the grinder wheel, an extension of table's mounting tabs or flanges 22 and 24 at an “a” angle between 50° and 60° will extend the table 20 at a corresponding angle “b” between 30° and 40° from the grinding wheel 78. Such 30°-40° range of the adaptor's grinding angles or bevel “a” includes commonly desired bevel angles of mower blades, with a 30° bevel being provided for cutting fine bladed lawns and a 40° bevel being used for mowing rough vegetation. Accordingly, the preferred angle “b” between the mounting tabs 22 and 24 and the table 20 is preferably between 50° and 60°. The angles of the feet 15 and 17 with respect to the legs 6 and 8 preferably match such angle “b” so that the table 20 is held at a substantially horizontal orientation upon placement of the feet 15 and 17 upon a horizontal work surface.

A permanent magnet 26 may be advantageously mounted at the proximal end of the table 20, such magnet resisting vibration induced separations of the blade 90 from the table 20 during grinding operations.

While the principles of the invention have been made clear in the above illustrative embodiment, those skilled in the art may make modifications to the structure, arrangement, portions and components of the invention without departing from those principles. Accordingly, it is intended that the description and drawings be interpreted as illustrative and not in the limiting sense, and that the invention be given a scope commensurate with the appended claims.