IES960210A2 - An improved chasing means - Google Patents

Abstract

The invention discloses a hand-held tool intended for cutting channels into the surfaces of mineral building materials, and comprising a pair of spaced-apart proprietary cutting discs mounted upon a common motorised rotating spindle, a casing which encloses the exposed segments of the discs and which communicates with a vacuum extraction means, and adjustable surface-engaging wheels or rollers which control the depth of the channel being cut. The specification envisages a modified proprietary angle-grinder and well as a purpose-built tool. <Fig. 2>

Description

An improved chasing means The invention discloses a hand-held tool intended for cutting channels into the surfaces of mineral building materials, and comprising a pair of spaced-apart proprietary cutting discs mounted upon a common motorised rotating spindle, a casing which encloses the exposed segments of the discs and which communicates with a vacuum extraction means, and adjustable surface-engaging wheels or rollers which control the depth of the channel being cut. The specification envisages a modified proprietary angle-grinder and well as a purposebuilt tool. Τ’—--TRUE COPY AS lodged —--ABPUCAT?C?J fit S 9 6 0 2J,0 Specification for an Improved Chasing Means The present specification discloses an improved means for cutting channels or grooves into the surfaces of mineral building materials such as concrete, plaster S and asphalt (usually in order to enable electrical conduit, gas or water piping or other similar service to be retro-fitted beneath the aforementioned surfaces), a process known as ’chasing’. In particular there is disclosed a hand-held tool which is iO specifically designed for the purpose of chasing such channels or grooves.

Background Hitherto, conduits and pipes have been retro-fitted beneath the surfaces of walls, floors and roadways by iS chasing out grooves or channels using general-purpose tools, such as power chisels or angle grinders, which were not especially designed or intended for chasing.

In practice it is found that power chisels are unacceptably noisy; they generally produce grooves Ίο having rough untidy edges which are incompatible with skimmed plaster walls; and their percussive effects are conducted through adjacent masonry where they are known frequently to produce cracks in fresh mortar joints and plasterwork elsewhere in the building. Ί£ With regard to general-purpose angle grinders fitted with abrasive cutting discs or diamond-tipped cutting IE 960210 wheels, the procedure for cutting a groove or channel is laborious insofar as it is necessary first to cut a narrow slit to one side of the intended channel, then to cut a second narrow slit to the other side of said channel, and then to clean away the material between the slits in order to form the channel. Moreover, the cutting process generates thick clouds of mineral dust which affect the breathing and vision of the operative, making it difficult for him to see exactly where (or even what) he is cutting, and this state of affairs is clearly unacceptable from the point of view of the health, safety and wellbeing of the operative.

Objective It is the main objective of the present invention to provide a special-purpose chasing machine or alternatively an inexpensive attachement for existing proprietary portable angle grinders which will enable pairs of spaced-apart narrow slits to be cut simultaneously. It is a second objective of the Ιό invention to provide an ergonomically balanced chasing machine which is provided with means for containing and removing most of the dust which is generated by the chasing process.

Consistory A chasing means for cutting a channel which is constructed according to the invention comprises at least the following components: a prime mover which causes rotary motion of a spindle; IE 960210 a means for safely controlling the prime mover; a pair of substantially identical proprietary cutting discs which are securely but removably mounted upon the spindle or an extension thereof, such that the cutting discs are concentric with the axis of the spindle and spaced apart by a distance equal to the width of the channel which is to be cut; a casing or hood which encloses the discs, excepting only those segments of the discs which are intended to IO penetrate the channel which is to be cut: a means for adjustably increasing or decreasing the depth of the exposed segments of the discs whilst substantially maintaining the integrity of enclosure of the unexposed portions of the discs, together with i5 at least two surface-engaging wheels or rollers which are so disposed as to enable the assembly to rest upon and roll over the surface which is to be cut whilst maintaining the depth of the cut; a means for connecting a conventional vacuum *2.0 extraction hose to the inside of the casing or hood; and at least two handles which are so disposed as to enable the assembly to be safely and conveniently carried to and from a site, and to be guided along the path of a cut.

Preferably, a right-angle drive is provided between the prime mover and the spindle so that the tool has a profile which is generally long and narrow, making it ergonomically easy to hold and to guide, and 2>o simultaneously enabling grooves to be chased in surfaces in close proximity to projecting obstacles. Preferably, the prime mover and its controls and. at least one handle take the form of a proprietary angle grinder powered by an electric motor or by an internal IE 960210 combustion engine, though optionally the prime mover may be a compressed-air motor or an hydraulic motor. Preferably also, the cutting discs should take the form of diamond-tipped steel wheels, though optionally they may be bonded-abrasive ceramic-type wheels.

Preferbly also, the casing may incorporate a removable panel in order to facilitate the fitting and removal of the cutting discs and adjustment of their distance apart. io Optionally, the casing may be provided with means for connecting a water hose in order that water may be sprayed upon the cutting discs during the cutting process .

Preferred Embodiment lS The invention will be more clearly understood by reference to the following description of a preferred embodiment thereof, given by way of example only without prejudice to the Claims, and to the accompanying drawings in which: Ίο Figure 1 shows a plan view of a chasing machine constructed according to the invention; Figure 2 shows a side view of the same machine; Figure 3 shows an end section through the axis of the spindle; and Figure 4 shows a side section through the casing.

IE 960210 Referring first to Figure 1, there is seen a conventional proprietary electrically-powered angle grinder 1 which incorporates a rear handle 2. Attached to the angle grinder 1 is a casing 3 which is £ secured to a projecting boss (not seen) on the the angle grinder 1 by a set-screw 4. The casing 3 is provided with means for fixing a front handle 5 and it also incorporates a socket 6 for a vacuum hose 7 which may be connected to a conventional proprietary vacuum cleaner or extractor (not shown).

Figure 2 shows that the angle grinder 1 is equipped with a proprietary safety switch 8, and it is further seen that the bottom of the casing 3 is cut away, allowing a pair of cutting discs 9 to project below 1½ the casing. There is seen a pair of rollers 10 which are carried in a subframe 11 which is pivotable relative to the casing 3 at its back end about a pivot 12, and which is securable in an elongated slot 13 adjacent to its front end by a clamping screw 14. The Ί0 rollers 10 are intended to roll upon the surface which is to be cut, and the position of the subframe 11 in the slot 13 is intended to control the depth of the cut by limiting the amount by which the cutters 9 project below the casing 3. The configuration of the subframe is intended to contain the periphery of the cutting discs adjacent to the surface being cut, thus preventing accidental contact with the cutting discs and also hindering dust which is trying to escape outside the casing. 3o Referring now to Figure 3, it is seen that the nut which would normally have been used for securing a single grinding wheel on to the spindle of the angle IE 960210 grinder 1 has been removed and replaced by a cylindrical extension piece 15 whose outside diameter is substantially the same as the inside diameter of the cutting discs 9. Spacers 16 are used to separate the two discs 9 by an appropriate distance apart, and the sandwich assembly is secured by a special clamp screw 17 which is screwed into the end of the extension piece 15. A removable panel 18 in the casing 3 is provided for access to the wheel mounting ID components 15, 16 and 17.

Figure 3 also shows how the casing 3 is secured to the projecting boss of the angle grinder 1 by the setscrew 4. The illustration further shows one of the roller assemblies 10, and it is seen that the iS individual rollers are located not only between the insides of the subframe 11, but also that they project beneath the head-end of the angle grinder 1, the objective being to reduce operative fatigue and to facilitate guiding the tool. 2.0 Finally, Figure 4 shows how the subframe 11 fits adjustably inside the casing 3, simultaneously acting as a safety guard and obstructing dust which may otherwise try to escape throughthe gap between the underside of the casing and the surface being chased.

IE 960210 Summary It is seen that the objectives of the invention have been achieved, in that there is provided an inexpensive attachment for existing proprietary £ portable angle grinders (or alternatively a specialpurpose chasing machine) which enables pairs of spaced-apart narrow slits to be cut simultaneously, and that the attachment (or machine) is ergonomically balanced and provided with means for containing and (0 removing most of the dust which is generated by the chasing process.

However the invention is not limited to the particular embodiment described above, major details of which may be departed from without affecting the validity of the iS Claims. For example, various alternative means could be provided for mounting the cutting discs upon the extended spindle, and it is envisaged that for heavy work, the mounting means might incorporate at least one extra bearing. Similarly it is envisaged that in 2.0 a different embodiment, the prime mover could be located remotely from the spindle (for example, standing upon the floor nearby) and connected to the cutting assembly by, for example, a flexible drive shaft contained inside a flexible casing.

It will be readily apparent that different embodiments can be conceived which are nevertheless covered by the

Claims (5)

1. A chasing means for cutting channels which comprises at least the following components: a prime mover which causes rotary motion of a spindle; a means for safely controlling the prime mover; a pair of substantially identical proprietary cutting discs which are securely but removably mounted upon 10 the spindle or an extension thereof, such that the cutting discs are concentric with the axis of the spindle and spaced apart by a distance equal to the width of the channel which is to be cut; a casing or hood which encloses the discs completely, lS excepting only those segments of the discs which are intended to penetrate the channel which is to be cut: a means for adjustably increasing or decreasing the depth of the exposed segments of the discs whilst substantially maintaining the integrity of enclosure 2.0 of the unexposed portions of the discs, together with at least two surface-engaging wheels or rollers which are so disposed as to enable the assembly to rest upon and roll over the surface which is to be cut whilst maintaining the depth of the cut; a means for connecting a conventional vacuum extraction hose to the inside of the casing or hood; and at least two handles which are so disposed as to enable the assembly to be safely and conveniently 3. O carried to and from a site, and to be guided along the path of a cut. IE 960210

2. A chasing means as described in Claim 1, and further characterised by using a proprietary angle grinder as the prime mover.

3. A chasing means as described in 2 above, and S further characterised by the provision of a removable panel in the casing to facilitate fitting, adjustment and removal of the cutting discs.

4. A chasing means as described in 3 above, and further characterised by using a pair of proprietary io diamond tipped cutting discs.

5. A chasing means as described in 4 above, and further characterised by the provision of means for spraying water upon the cutting discs.