TECHNICAL FIELD OF THE INVENTION

This invention relates to an improved angle grinder. BACKGROUND ART

An angle grinder is a hand held power tool having a rapidly rotating abrasive cutting or grinding disk, for use in cutting, grinding or polishing metal or masonry.

Angle grinders are widely used in metalworking and construction and may be used both for removing excess material from or simply cutting into a piece of masonry, or other materials. The discs, which come in a variety of hardnesses, grits, and materials, wear down with use and can be replaced as needed.

Angle grinders are commonly used in the construction industry for chasing grooves into walls or like surfaces, to allow for electrical cables, electrical conduit and plumbing pipes or any other product requiring concealment, to be concealed therein. However, in most instances at least 2 parallel grooves are required to be chased into a wall, and the central portion needs to be removed, in order to provide chasing which is sufficiently wide.

Ensuring that the two grooves are parallel and equidistant from one another is not an easy task.

Chasing tools are known in the art and generally comprise an angle grinder having two parallel grinding blades located to one side of the nose of the grinder, within a single fixed guard. However the grinding blades of these tools are small by necessity to ensure that the tool remains balanced and as such are limited in the depth to which they can grind and the width of the groove that they are able to chase. Furthermore due to the reduced circumference of the blade they are required to rotate faster, which often causes the grinder motor and the cutting discs mounted on the grinder to overheat.

It is an object of this invention to provide a power tool which, at least partially, alleviates some of the abovementioned problems. DISCLOSURE OF THE INVENTION

In accordance with this invention, there is provided a power tool attachment for use in cutting grooves in masonry, the attachment comprising an elongated nose, securable to the body of a power tool, the nose including a rotatable shaft locatable through its front end and a pair of rotatable cutting discs removably securable onto the shaft.

There is further provided for the cutting disks to be securable onto the shaft either on the same or opposite sides of the nose.

In a preferred embodiment of the invention, the cutting disks are securable to opposite sides of the nose.

A rotating bevel gear or other means for rotating the shaft may be located in the main body of the power tool, the rotating bevel gear may engage with the shaft located in the nose to drive rotation of the shaft.

The bevel gear, and subsequently the rotation of the shaft may be driven by an electric motor housed either within or externally to the body of the power tool and powered by a standard power source, alternatively powered by a combustion engine.

The power tool attachment may additionally include means for limiting the depth of the grooves that the cutting discs may cut. The limiting means may include a surface- engaging roller locatable on the nose. The location of the roller along the nose may be altered depending on the function that the attachment is required to perform.

The limiting means may additionally include a housing locatable around at least a portion of each cutting disk. The housing may also act as a safety guard, for preventing unauthorised contact with the cutting discs.

The power tool attachment may further include means for adjusting the distance between the two discs, the adjustment means including removable spacers locatable on the shaft, adjacent the nose. The means for removably securing the cutting discs on the shaft may include a threaded nut or clamping screw.

The two cutting discs are preferably the same size.

The body of the power tool may additionally include one or more handles by which the tool may be carried, and which may be used to guide the tool in use.

In an alternative embodiment of the invention, the attachment may be incorporated into the body of the power tool as a universal integral part.

In this embodiment the attachment and the body may be formed as a single moulded unit, and the attachment is not required to be bolted onto the body of the power tool.

The power tool is preferably an angle grinder.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below by way of example only and with reference to the following drawings, in which:

Figure 1 is a representation of the power tool attachment;

Figure 2 is a representation of a hand held power tool in which the attachment forms an integral part of the power tool;

and

Figure 3 is an exploded view of the hand held power tool of the power tool of figure 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to figures 1 to 3 in which like features of the invention are represented by like numbers.

Figure 1 illustrates an attachment 40 for an angle grinder 10. The attachment 40 includes a nose 14, through which a shaft 16 is locatable, and a pair of cutting discs 18 securable on the shaft 16 to either side of the nose 14. The cutting discs 18 are secured to the shaft 16 by a threaded nut, or clamping screw 19. The cutting discs 18 are of equal diameter and size. The attachment 40 is connectable to the body 12 of the angle grinder 10 by screws or bolts 42. The nose 14 is adapted to receive a bevel gear 44, extending from the body 12 of the angle grinder 10. The bevel gear 44 engages with the shaft 16, to rotate the shaft and subsequently the cutting disks 18.

A surface-engaging roller 20 is located at the front of the nose 14. The roller 20 assists in guiding the angle grinder along the intended path, and also assists in limiting the depth to which the cutting discs may cut into the relevant surface.

A housing 22 surrounds at least a portion of each cutting disk 18, and acts as a safety guard, preventing accidental contact with the discs 18, as well as assisting in limiting the depth to which the discs 18 may cut. (It is envisaged the amount by which the discs 18 extend beyond the housing may be adjusted).

Spacers such as washers (not shown), may be located on the shaft 16, adjacent the nose 14, prior to the addition of the discs 18. The spacers increase the distance between the two discs 18, and the width of the spacers will determine the width of the groove to be cut in the relevant surface. Where necessary, the spacers may be removed completely.

A handle 24, is located on the body 12 of the angle grinder 10, and may be used to guide the path of the grinder 10, as well as to carry the grinder.

It is envisaged that the angle grinder will be driven by an electric motor, housed within the body 12 of the angle grinder, and powered by a standard electrical power source. Where a standard electrical power source is not available, a combustion engine may be employed to drive the grinder.

Referring to figures 2 and 3, and in an alternative embodiment of the invention, the angle grinder 10 includes the modified nose 14 as an integral part of the body 12. In this embodiment, the angle grinder is manufactured as a single unit, incorporating the nose 14. All other features of the angle grinder are the same as those referred to in Figure 1 , and are indicated by like numerals.

The cutting discs include diamond tipped cutting discs, commonly used for cutting into masonry. Other discs may be used where relevant.

In use, the grinder 10 is brought into contact with a wall, or other surface in which it is desired to cut a set of parallel grooves. The motor is activated, which in turns causes the discs 18 to rotate at high speed. The grinder is pushed down into the wall surface, until the roller 20 makes contact with the wall. Using the handle 22, the grinder is then pulled along the wall in the direction of the cut to be made, the discs 18 causing two parallel cuts to be made in the masonry surface. Once the required cut is made, the grinder 10 is turned off, and the material remaining between the two parallel cuts can be cleared using a chisel or other relevant tool.

Numerous modifications to this embodiment are possible, without departing from the scope of the invention.

The invention therefore provides an attachment for an angle grinder and a novel angle grinder for chasing parallel grooves in masonry and the like.