Safety attachment for lawn mowers

Abstract

A safety attachment is provided for use with a rotary lawn mower to prevent substantial injury to anyone whose extremity may accidentally strike the cutter. The attachment includes a relatively large annular disc mounted to the drive shaft of the motor for rotation about a vertical axis and at least one cutter bar mounted diametrically across the disc on the underside thereof. The disc diameter is substantially equal to the length of the cutter bar. In one embodiment slots are provided adjacent to the leading edges of the cutter bar and impellers are provided on the upper side of the disc adjacent the slot for discharging cut grass through the side of the machine. The combination of the disc and the cutter bar provides good grass cutting action and at the same time greatly reduces the risk of serious injury in the event that one's foot, for example, accidentally slips in under the mower.

Having thus described the invention, what I claim and desire to obtain by Letters Patent of the United States is: 
     
       1. A safety attachment for a rotary lawn mower having a motor and a drive shaft mounted thereto, comprising: a generally rigid disc mountable to the lower end of said shaft, the underside of said disc presenting a substantially flat, smooth continuous surface and the periphery thereof presenting a smooth, continuous substantially circular edge; and   a cutter bar having substantially planar upper and lower surfaces and being detachably mounted diametrically across and with said upper surface directly flushly against the underside surface of said disc over substantially the full upper surface of the bar, the length of said cutter bar being substantially equal to the diameter of said disc with the ends of said .[.bars.]. .Iadd.bar .Iaddend.being substantially even with the peripheral edge of said disc, said cutter bar being rectangular in cross section, each longitudinal edge of said bar providing a cutting edge when in cutting position with respect to said disc, the cutting position of each longitudinal edge being that position occupied by said longitudinal edge when disposed at a lower forward edge of said bar relative to the direction of rotation of said disc and said bar, the bar acting in a horizontal cutting plane to cut material brought into contact therewith.   
     
     
       2. A safety attachment, according to claim 1, including at least a second cutter bar diametrically and detachably mounted to and directly flat against the lower face of said disc and intersecting said first bar. 
     
     
       3. A safety attachment, according to claim 1, wherein the bar is straight. 
     
     
       4. A safety attachment, according to claim 1, and further comprising releasable connecting means for detachably mounting said bar to said disc. 
     
     
       5. A safety attachment for a rotory lawn mower having a motor and drive shaft mounted thereto, comprising: a disc mountable to the lower end of said shaft, the underside of said disc presenting a substantially planar, continuous surface with the periphery of the disc presenting a continuous substantially circular edge;   a cutter bar mounted diametrically across the underside of said disc, full upper surfaces of the cutter bar being mounted flushly against the underside surface of said disc, a lower forward edge of said bar acting in a horizontal cutting plane to cut material brought into contact therewith, the length of said cutter bar being substantially equal to the diameter of said disc with the ends of said bar being substantially even with the peripheral edge of said disc; and   releasable connecting means for detachably mounting said bar to said disc.   
     
     
       6. A safety attachment, according to claim 5, wherein said connecting means includes a groove formed diametrically across the underside of said disc, said groove having a depth less than the thickness of said bar. 
     
     
       7. A safety attachment, according to claim 5, wherein said connecting means includes a pair of diametrically spaced studs mounted to the underside of said disc, said bar being formed with a pair of longitudinally spaced openings adapted to receive said studs when said bar is in position against said disc. 
     
     
       8. A safety attachment, according to claim 7, wherein said openings are keyhole shaped. .Iadd. 9. A cutting structure for a rotary lawn mower having a motor and a drive shaft mounted thereto, comprising: a generally rigid disc mountable to the lower end of said shaft, the underside of said disc presenting a substantially flat, smooth continuous surface and the periphery thereof presenting a smooth, continuous substantially circular edge; and   a cutter bar having substantially planar exterior surfaces and being mounted diametrically across and directly flushly against the underside surface of said disc over substantially the full upper surface of the bar, the length of said cutter bar being substantially equal to the diameter of said disc with the ends of said bar being substantially even with the peripheral edge of said disc, said cutter bar being rectangular in cross section, at least certain longitudinal edges of said bar providing cutting edges, the bar acting in a cutting plane to cut material brought into contact therewith. .Iaddend..Iadd. 10. A cutting structure for a rotary lawn mower having a motor and a drive shaft mounted thereto, comprising:   a generally rigid disc mountable to the lower end of said shaft, the underside of said disc presenting a substantially flat surface and the periphery thereof presenting a substantially circular edge; and,   a cutter bar carried by the disc and extending diametrically across the disc against the underside surface of said disc, the length of said cutter bar being substantially equal to the diameter of said disc with the ends of said bar being substantially even with the peripheral edge of said disc, said cutter bar being rectangular in cross section, at least certain longitudinal edges of said bar providing cutting edges, the bar acting in a cutting plane to cut material brought into contact therewith. .Iaddend. .Iadd. 11. A cutting structure for a rotary lawn mower having a motor and a drive shaft mounted thereto, comprising:   a generally rigid disc mountable to the lower end of said shaft, the underside of said disc presenting a substantially flat surface and the periphery thereof presenting a substantially circular edge; and   a cutter bar having substantially planar upper and lower surfaces and being mounted diametrically across and with said upper surface directly flushly against the underside surface of said disc over at least medial portions of the full upper surface of the bar, the length of said cutter bar being substantially equal to the diameter of said disc with the ends of said bars being substantially even with the peripheral edge of said disc, said cutter bar being rectangular in cross section, at least certain longitudinal edges of said bar providing cutting edges, the bar acting in a cutting plane to cut material brought into contact therewith. .Iaddend..Iadd. 12. In a rotary mower having a motor and a drive shaft mounted thereto, a cutting structure mounted for rotary movement with the drive shaft, comprising:   a substantially rigid disc portion carried by the drive shaft; and,   a cutter bar portion carried by the disc portion on a face thereof facing material which is to be mowed, the cutter bar portion extending in a material cutting mode across the disc portion without the ends of said cutter bar portion extending beyond the peripheral edge of the disc portion. .Iaddend. .Iadd. 13. In the rotary mower of claim 12 wherein the cutter bar portion is uniform in thickness and lower surfaces of the cutter bar portion are spaced from the underside of the disc portion a distance equal to the thickness of the cutter bar portion. .Iaddend..Iadd. 14. In the rotary mower of claim 12 wherein lower surfaces of the cutter bar portion are spaced from the underside of the disc portion a distance equal to the greatest thickness of the cutter bar portion. .Iaddend..Iadd. 15. In the rotary mower of claim 12 wherein the cutter bar portion is rectangular in cross section, at least certain edges of said bar providing cutting edges, the bar acting in a cutting plane to cut material brought into contact therewith. .Iaddend..Iadd. 16. In the rotary mower of claim 12 wherein at least medial portions of the cutter bar portion are contiguous with said face of the disc portion. .Iaddend..Iadd. 17. In the rotary mower of claim 12 wherein the cutter bar portion is contiguous along its length with said face of the disc portion. .Iaddend. .Iadd. 18. In the rotary mower of claim 12 and further comprising means carried by the disc portion for creating an air flow sufficient to discharge mowed material from the mower. .Iaddend..Iadd. 19. In the rotary mower of claim 12 and further comprising means operable with the disc portion and drive shaft for creating an air flow sufficient to discharge mowed material from the mower. .Iaddend..Iadd. 20. In the rotary mower of claim 12 wherein the cutter bar portion is rectangular in cross section at least at medial portions thereof. .Iaddend..Iadd. 21. In the rotary mower of claim 12 wherein the disc portion and cutter bar portion are disposed and rotate in a substantially horizontal plane to face material which is to be mowed. .Iaddend..Iadd. 22. In the rotary mower of claim 12 wherein the cutter bar portion extends diametrically across the disc portion and is substantially equal in length to the diameter of the disc portion. .Iaddend..Iadd. 23. In the rotary mower of claim 12 wherein the cutter bar portion extends across the disc portion at its longest dimension and is substantially equal in length to said longest dimension. .Iaddend. .Iadd. 24. In the rotary mower of claim 12 wherein the surface of the disc portion facing the material which is to be mowed is provided with a groove within which at least a portion of the cutter bar portion is received to facilitate mounting of the cutter bar portion to the disc portion. .Iaddend..Iadd. 25. In the rotary mower of claim 12 wherein surface portions of the cutter bar portion are planar. .Iaddend. .Iadd. 26. In the rotary mower of claim 12 wherein the cutter bar portion extends diametrically across the disc portion. .Iaddend..Iadd. 27. In the rotary mower of claim 26 wherein at least medial portions of the cutter bar portion are contiguous with said face of the disc portion. .Iaddend..Iadd. 28. In the rotary mower of claim 26 wherein the cutter bar portion is contiguous along its length with said face of the disc portion. .Iaddend..Iadd. 29. In the rotary mower of claim 12 and further comprising means for mounting the cutter bar portion to the disc portion to prevent extension of the ends of the cutter bar portion beyond the peripheral edge of the disc portion. .Iaddend..Iadd. 30. A cutting structure adapted to be mounted for rotary movement with a drive shaft, comprising:   a substantially rigid disc portion carried by the drive shaft; and   a cutter bar portion carried by the disc portion on one face thereof, the cutter bar portion extending in a material cutting mode across the disc portion without the ends of said cutter bar portion extending beyond the peripheral edge of the disc portion. .Iaddend. .Iadd. 31. The cutting structure of claim 30 wherein the cutter bar portion extends diametrically across the disc portion. .Iaddend..Iadd. 32. The cutting structure of claim 30 and further comprising means for mounting the cutter bar portion to the disc portion to prevent extension of the ends of the cutter bar portion when the cutter bar portion is in a material cutting mode beyond the peripheral edge of the disc portion. .Iaddend..Iadd. 33. The cutting structure of claim 30 wherein the cutting structure is adapted to be mounted for rotary movement with the drive shaft of a rotary mower, the disc portion and the cutter bar portion being disposed and rotating in a substantially horizontal plane to face material which is to be mowed. .Iaddend..Iadd. 34. In a rotary mower having a motor and a drive shaft mounted thereto, a cutting structure mounted for rotary movement with the drive shaft, comprising:   a substantially rigid disc portion carried by the drive shaft; and   a cutter bar portion carried by the disc portion on a face thereof facing material which is to be mowed, the cutter bar portion extending diametrically across the disc portion without the ends of said cutter bar portion extending beyond the peripheral edge of the disc portion. .Iaddend..Iadd. 35. In the rotary mower of claim 34 wherein the cutter bar portion is substantially equal in length to the diameter of the disc portion. .Iaddend. .Iadd. 36. A cutting structure adapted to be mounted for rotary movement with a drive shaft, comprising:   a plate portion carried by the drive shaft; and,   a cutter bar portion carried by the plate portion on one face thereof, at least portions of the cutter bar portion being flush with said face, the cutter bar portion extending across the plate portion at its longest dimension and being substantially equal in length to the longest dimension of the plate portion. .Iaddend..Iadd. 37. The cutting structure of claim 36 wherein the plate portion is substantially circular and wherein the cutter bar portion extends diametrically across the plate portion. .Iaddend..Iadd. 38. The cutting structure of claim 36 wherein the plate portion is substantially circular in conformation. .Iaddend. .Iadd. 39. In a rotary mower having a motor and a drive shaft mounted thereto, a cutting structure mounted for rotary movement with the drive shaft, comprising:   a substantially rigid disc portion carried by the drive shaft; and   a cutter bar portion carried by the disc portion on a face thereof facing material which is to be mowed, the cutter bar portion extending across the disc portion at the longest dimension of the disc portion and being substantially equal in length to said longest dimension, the ends of said cutter bar portion lying within the extent of the peripheral edge of the disc portion. .Iaddend..Iadd. 40. A cutting structure adapted to be mounted for rotary movement with a drive shaft, comprising:   a substantially circular plate portion carried by the drive shaft; and,   a cutter bar portion carried by the drive shaft, at least medial portions of the cutter bar portion being disposed flushly against one face of the plate portion, the cutter bar portion extending diametrically across the plate portion without the ends of said cutter bar portion extending beyond the peripheral edge of the plate portion. .Iaddend. .Iadd. 41. The cutting structure of claim 40 wherein the cutter bar portion is contiguous along its length with said face of the plate portion. .Iaddend..Iadd. 42. The cutting structure of claim 40 wherein said face of the plate portion faces material which is to be mowed and the plate portion and cutter bar portion rotate on the drive shaft in a substantially horizontal plane. .Iaddend..Iadd. 43. The cutting structure of claim 40 wherein the cutter bar portion is contiguous along its length with said face of the plate portion. .Iaddend..Iadd. 44. The cutting structure of claim 43 wherein said face of the plate portion faces material which is to be mowed and the plate portion and cutter bar portion rotate on the drive shaft in a substantially horizontal plane. .Iaddend..Iadd. 45. The cutting structure of claim 44 wherein the plate portion is substantially circular in conformation. .Iaddend.