GB2366754A

GB2366754A - Rotary cutting or grinding tool

Info

Publication number: GB2366754A
Application number: GB0022856A
Authority: GB
Inventors: Michael John William Brown; Mario Halbeisen
Original assignee: Marcrist International Ltd
Current assignee: Marcrist International Ltd
Priority date: 2000-09-16
Filing date: 2000-09-16
Publication date: 2002-03-20
Also published as: GB0022856D0

Abstract

A rotary cutting or grinding tool comprises at least two concentric rows of diamond containing cutting elements 12,6 attached to a substantially tubular or circular support member 10,1. The elements 12,6 are substantially quadrilateral in plan (e.g. square or rectangular) and are dimensioned such that the lengths of adjacent sides are in a ratio no greater than 3:2. Cutting elements 6 in each row may be spaced apart by a distance substantially equal to the length of a side of an element, with elements 6 being arranged such that an element 6 in one row is next to a space between two elements 6 in the adjacent row. The cutting tool may comprise a tubular body 10 having two concentric rows of cutting elements 10 secured to the rim of the body, elements 10 of the two rows respectively projecting inwardly and outwardly from the rim.

Description

<Desc/Clms Page number 1> ROTARY CUTTING OR GRINDING TOOL Field of the Invention This invention relates to a rotary cutting or grinding tool, and particularly to such a tool having diamond-containing cutting elements thereon.

Background to the Invention In grinding discs of the type having diamond grit-containing cutting elements attached to a face thereof, used for example in the grinding of stone or concrete surfaces, a wide variety of configurations of cutting element have been used. For example, a plurality of circular elements can be arranged in a circle around the circumference of the disc, or overlapping rows of elongate elements may be curved to follow circular paths around the disc. In an alternative arrangement, the elements may be curved in a generally radial direction, often referred to as a "turbo" configuration. A general object has been to put as much diamond-carrying surface as possible in contact with the surface to be ground.

Hole-cutting tools for masonry and the like take the form of a tubular support having mounted on the rim thereof a plurality of cutting elements containing diamond grit, the elements being generally elongate and following the rim of the support.

Summary of the Invention It has now been found that by using a larger number of smaller cutting elements, grinding and cutting tools can be made which are more aggressive in attacking the surface to be ground or cut, while having a longer useful life.

According to the invention, there is provided a diamond-faced rotary cutting or grinding tool, comprising a generally circular or tubular support member having at least two concentric rows of diamond-containing cutting elements attached thereto, the elements being generally quadrilateral in plan and dimensioned such that the lengths of adjacent sides of the quadrilateral are in a ratio no greater than 3:2.

Preferably, the sides of the quadrilateral are substantially equal in length. The cutting elements are preferably rectangular.

The cutting elements in each row are preferably spaced apart by a distance substantially equal to the length of a side of an element, adjacent rows being arranged such

that an element in one row is next to a space between two elements in the next adjacent row. In one embodiment of the invention, three concentric rows of cutting elements are provided. Each cutting element is preferably arranged to present a substantially straight leading edge transversely to the direction of rotation of the tool, in use.

Where the support is a tube, a first row of the cutting elements may be attached to the inner edge of the rim of the support and a second row of the cutting elements is then attached to the outer edge of the rim of the support.

With the cutting or grinding tool of the invention, an improved cutting effect can be achieved without increasing the total mass of diamond-bearing material in contact with the surface to be cut or ground, contrary to current expectations in the art.

Brief Description of the Drawings In the drawings, which illustrate exemplary embodiments of the invention; Figure 1 is a plan view of the cutting face of a grinding disc; Figure 2 is a sectional view on line X-X in Figure 1; Figure 3 is an end view of a hole-cutting tool; and Figure 4 is a side elevation of the tool of Figure 3.

Detailed Description of the Illustrated Embodiments Referring first to Figures 1 and 2, the grinding disc comprises a dished steel support disc 1 provided with a central mounting hole 2 by which it can be mounted on the drive spindle of an angle grinder or like power tool. Dust extraction holes 3 are spaced around the disc, each straddling the sloping wall 4 of the dished portion of the disc and the generally flat peripheral region 5 of the disc on which the cutting elements 6 are mounted, for example by welding, suitably laser welding. The peripheral region 5 is provided with fine parallel circumferential grooves to assist in attachment of the elements 6.

The elements 6 each comprise a block of a support medium, for;example a metal alloy such as bronze, in which diamond particles are suspended, Each ele M- e6t,#s..-. is generally square in plan, and two rows of the elements are arranged around the disc, with each block aligned with a tangent to the edge of the disc at.the mid-point of the element. In the illustrated example, there are fifteen blocks equi-spaced around the disc

in the outer row, and five blocks evenly placed between the five dust extraction holes 3 to form the inner row. It will be appreciated, however, that greater or fewer numbers of elements 6 may be used in each row, although it is preferred that the elements in the inner row are not aligned in a radial direction with any elements in the outer row.

Referring now to Figures 3 and 4, a masonry hole-cutting tool comprises a tubular body 10, having a closed end carrying an internally threaded boss 11 for connection of the tool to an electric drill, this connection being entirely conventional. A plurality of diamond-containing cutting elements 12 are secured to the rim of the body 10, in two concentric staggered rows, with each element 12 occupying half the thickness of the rim and having a portion projecting outwardly or inwardly from the rim, depending on whether the element is part of the outer or inner row.

Each cutting element is approximately square in plan and is arranged with the leading edge thereof in the normal direction of rotation of the tool extending in a plane which is normal to a tangent to the rim at that point. The elements 12 are formed of a metal alloy, for example bronze, in which the diamond particles are evenly dispersed and supported, and are welded to the rim, for example by laser welding. It will be appreciated that in the illustrated embodiment, the cut in the masonry will be fairly wide; a narrower cut can be achieved by using smaller cutting elements, if desired increasing the number of elements employed.

Claims

CLAIMS 1 A diamond-faced rotary cutting or grinding tool, comprising a generally circular or tubular support member having at least two concentric rows of diamond- containing cutting elements attached thereto, the elements being generally quadrilateral in plan and dimensioned such that the lengths of adjacent sides of the quadrilateral are in a ratio no greater than 3:2.
2. A cutting or grinding tool according to Claim 1, wherein the lengths of adjacent sides of the quadrilateral are substantially equal.
3. A cutting or grinding tool according to Claim 1 or 2, wherein the cutting elements are substantially rectangular in plan.
4. A cutting or grinding tool according to Claim 1, 2 or 3, wherein the cutting elements in each row are spaced apart by a distance substantially equal to the length of a side of an element, adjacent rows being arranged such that an element in one row is next to a space between two elements in the next adjacent row.
5. A cutting or grinding tool according to any preceding claim, comprising three concentric rows of cutting elements.
6. A cutting or grinding tool according to any preceding claim, wherein each cutting element is arranged to present a substantially straight leading edge transversely to the direction of rotation of the tool, in use.
7. A cutting or grinding tool according to any of Claims 1 to 4, wherein the support is a tube and a first row of the cutting elements is attached to the inner edge of the rim of the support and a second row of the cutting elements is attached to the outer edge of the rim of the support.
8. A diamond-faced rotary cutting or grinding tool, substantially as described with reference to, or as shown in, the drawings.