Method for removing trip hazards in concrete sidewalks

• US 7,143,760 B2
• Filed: 02/21/2006
• Issued: 12/05/2006
• Est. Priority Date: 05/24/2002
• Status: Expired due to Term

• Current Assignee: Precision Concrete Cutting Incorporated
• Original Assignee: Precision Concrete Cutting Incorporated
• Inventors: Gardner, M. Ballard
• Primary Examiner(s): Wilson, Lee D.
• Application Number:
  US11/358,755
• Publication Number:
  US 20060141917A1
• Time in Patent Office: 287 Days
• Field of Search: 125/25, 125/18, 451/548, 451/353, 451/41, 451/28
• US Class Current: 125/25
• CPC Class Codes: B23D 45/16 Hand-held sawing devices with circular saw blades
• CPC Class Codes: B24B 23/028 Angle tools
• CPC Class Codes: B24D 5/123 having different cutting segments
• CPC Class Codes: B24D 5/16 Bushings; Mountings
• CPC Class Codes: B27B 5/08 for sawing with the saw blade abutting parallel against a surface of the workpiece
• CPC Class Codes: B27B 5/32 Devices for securing circular saw blades to the saw spindle
• CPC Class Codes: B28D 1/04 with circular or cylindrical saw-blades or saw-discs B28D1/10 takes precedence

Abstract

A method for cutting a chamfer on an edge of a concrete slab, comprising the steps of: providing a generally circular, rotatable concrete saw blade that is coupled to a right-angle grinder motor with a blade-mounting hub having no blade attachment hardware projecting below a lower major surface of the blade; making an initial planar cut at a desired angle beginning a distance from the edge, thereby creating an initial cantilevered ledge above the initial cut; if the initial cantilevered ledge is not severed from the slab by a cutting action of the blade before the hub is proximate an edge of the initial cantilevered ledge, then fracturing and removing the initial cantilevered ledge from the slab; and making at least one subsequent planar cut continuous with the initial cut and any necessary fracturings and removals of subsequent cantilevered ledges until the chamfer is complete.

Claims

1. A method for cutting a chamfer on an edge of a concrete slab, the method comprising the steps of:

providing a generally circular, rotatable concrete saw blade that is coupled to a right-angle grinder motor with a blade-mounting hub having no blade attachment hardware projecting below a lower major surface of the blade;

making a planar cut at a desired angle beginning a distance from said edge, the planar cut creating a cantilevered ledge above the planar cut;

fracturing and removing at least a portion of the cantilevered ledge from the slab whenever an edge of the cantilevered ledge is proximate the hub; and

continuing the planar cut until the cantilevered ledge is severed from the slab.

2. The method of claim 1, wherein the desired angle, measured by the angle which the lower surface of the blade makes with the uncut slab, is less than or equal to about seven degrees.

3. The method of claim 1, wherein said blade has a diameter of about 8 inches.

4. The method of claim 1, wherein said planar cut is performed with no water cooling of the blade.

5. The method of claim 1, wherein:

said hub includes an attachment collar, a blade mounting flange, and a blade centering shoulder on a lower surface of the flange, said collar having a central mounting aperture that is threaded to spirally engage the output spindle, said flange being equipped with multiple blade attachment holes that are perpendicular to an axis of rotation of the output spindle and generally evenly spaced about said axis;

said concrete saw blade has metal matrix edge in which diamond grit is embedded, said blade having a central positioning aperture sized to fit over the blade centering shoulder, said blade also having multiple countersunk holes which align with the blade attachment holes of the flange; and

said concrete saw blade is attached to said flange with multiple blade attachment screws having countersinking heads, said countersinking heads being flush with a lower surface of the blade when the blade is secured to the flange with said screws.

6. The method of claim 5, wherein said blade attachment holes are threaded to engage the blade attachment screws.

7. The method of claim 5, wherein said blade attachment holes are unthreaded, and nuts biased against an upper surface of the flange are employed to secure an end of each screw opposite the countersinking head.

8. The method of claim 7, wherein each of said nuts is of a self-locking type.

9. The method of claim 5, wherein said collar has a pair of flattened parallel sides sized to receive a wrench, with which said hub may be tightened onto said threaded output spindle.

10. The method of claim 5, wherein each of said blade attachment holes in said flange are countersunk to receive a portion of the countersinking head of a blade attachment screw.

11. A method for cutting a chamfer along an upper abutting edge of a first of two abutting concrete slabs, said abutting edge being elevated above an upper surface of said second concrete slab, the method comprising the steps of:

providing a generally circular, rotatable concrete saw blade that is coupled to a right-angle grinder motor with a blade-mounting hub having no blade attachment hardware projecting below a lower major surface of the blade;

making a planar cut at a desired angle beginning a distance from said upper abutting edge, said desired angle being selected so that a projection of a bottom surface of the planar cut intersects an upper abutting edge of the second concrete slab, the planar cut creating a cantilevered ledge above the planar cut;

fracturing and removing at least a portion of the cantilevered ledge from the slab whenever an edge of the cantilevered ledge is proximate the hub; and

continuing the planar cut until the cantilevered ledge is severed from the slab.

12. The method of claim 11, wherein the desired angle, measured by the angle which the lower surface of the blade makes with an upper surface of the second concrete slab, is less than or equal to about seven degrees.

13. The method of claim 11, wherein said blade has a diameter of about 8 inches.

14. The method of claim 11, wherein said planar cut is performed with no water cooling of the blade.

15. The method of claim 11, wherein:

said hub includes an attachment collar, a blade mounting flange, and a blade centering shoulder on a lower surface of the flange, said collar having a central mounting aperture that is threaded to spirally engage the output spindle, said flange being equipped with multiple blade attachment holes that are perpendicular to an axis of rotation of the output spindle and generally evenly spaced about said axis;

said concrete saw blade has metal matrix edge in which diamond grit is embedded, said blade having a central positioning aperture sized to fit over the blade centering shoulder, said blade also having multiple countersunk holes which align with the blade attachment holes of the flange; and

said concrete saw blade is attached to said flange with multiple blade attachment screws having countersinking heads, said countersinking heads being flush with a lower surface of the blade when the blade is secured to the flange with said screws.

16. The method of claim 15, wherein said blade attachment holes are threaded to engage the blade attachment screws.

17. The method of claim 15, wherein said blade attachment holes are unthreaded, and nuts biased against an upper surface of the flange are employed to secure an end of each screw opposite the countersinking head.

18. The method of claim 17, wherein each of said nuts is of a self-locking type.

19. The method of claim 15, wherein said collar has a pair of flattened parallel sides sized to receive a wrench, with which said hub may be tightened onto said threaded output spindle.

20. The method of claim 15, wherein each of said blade attachment holes in said flange are countersunk to receive a portion of the countersinking head of a blade attachment screw.