CONCRETE SAW WITH INTEGRATED PRESSURISED WATER FEED

Field of the Invention

The present invention relates to masonry saws of the type used for cutting concrete and the like- such saws commonly called concrete saws or consaws. The invention particularly relates a petrol powered consaw having an integrated pressurised water source driven from the same drive mechanism as the blade of the consaw.

Background

Consaws are well known in the art and are used for cutting concrete, bricks, tiles, stone and other similar material. Known consaws of the portable variety are driven by a petrol engine which drives the saw blade through a belt drive mechanism- the blade being mountable to a shaft which is rotated through action of the belt drive thereon. The blades are typically either of the diamond tip or abrasive variety and may be periodically replaced due to wear.

It is known for such saws to include a water feed point at the cutting surface to act as a coolant or lubricant during operation of the saw. To provide the water feed it is known to provide a water reservoir coupled to but independent of the consaw, the water reservoir operably being elevated above the actual blade. Water may then be fed under gravity from the reservoir to the blade where it may flow onto the blade to provide the necessary cooling effect.

Operation of such saws typically results in generation of large volumes of dust and residue material due to inadequate water flows and pressures at the time of cutting. These can provide for difficult working conditions especially in dry conditions where dust clouds may accumulate about the operator of the consaw. These may present health and safety issues. There is therefore a need for an improved consaw.

Summary

These and other problems are addressed by a consaw in accordance with the teaching of the present invention. Such a consaw provides a pressurised water flow at the blade of the saw, the volume of water flowing therefrom being sufficient to dampen the dusts generated through operation of the consaw. In this way, the dust will not rise up and about the operator of the saw. To provide the pressurised water flow, a consaw in accordance with the present teaching desirably includes means for pressuring a water flow integrated as part of the consaw. This means for pressuring includes an impeller and is driven from the same drive mechanism used for effecting movement of the consaw blade.

Accordingly, there is provided a consaw according to claim 1. Advantageous embodiments are provided in the dependent claims.

Brief Description Of The Drawings

The present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective view from the side of a blade portion of a consaw provided in accordance with the present teaching.

Figure 2 is a view from above of the consaw of Figure 1.

Figure 3 is an exploded view showing how the impeller may be coupled to the drive mechanism of the consaw. Figure 4 shows a variant to the consaw of Figure 1 with an adjustable nozzle provided to one side of the saw blade.

Figure 5 shows a perspective view of the consaw of Figure 4. Detailed Description Of The Drawings

Exemplary arrangements of a concrete saw or consaw provided in accordance with the present teaching will now be described with reference to the following figures. It will be appreciated and understood that these are provided to assist in an understanding of and benefits that may be derived from such a consaw and it is not intended that the scope of the present invention be construed as so limited to the specifics that are discussed herein.

As shown in Figures 1 and 2 a consaw 100 includes a blade 105 that is partially covered by a blade cover 110, which in use serves to protect the operator of the consaw from accidentally coming into direct contact with the blade 105 and causing injury. First and second water feed pipes 115, 120 are provided on opposite sides of the blade and are configured so as to be directed downwardly onto the exposed surface of the blade 105. In this way water that will exit from the water feed pipes will be directed down onto the surface of the saw blade 105 and the material which is being cut by that blade. Water will thereby directly flow onto the surface and will dampen any dust or other residues resultant from the cutting action. The water is pressurised such that the volume of water that is delivered at any moment is sufficient to counter any generated dust.

To provide the water at a pressurised level, the consaw includes means for pressuring the water flow 125. This may be provided in a number of different configurations- in the arrangement of Figures 1 and 2, it is provided as an impeller arrangement 200 provided inline between a water reservoir source (not shown) and the water feed pipes 110, 115. The impeller has an inlet 126 and an outlet 127. The inlet is coupled to a feed supply line for providing water from the reservoir, and the outlet 127 is coupled to the water feed pipes 115, 120. In the arrangement of Figure 1 , the water outlet 127 is coupled to a single fluid line 130 that bifurcates at a point away from the impeller to generate the first and second water feed pipes 115, 120. The single fluid line and the feed pipes are desirably coupled to the blade cover 110, so as to ensure that during operation they do not become snagged.

As will be understood by those skilled in the art, an impeller is a rotating component of a centrifugal pump and operably transfers energy from the motor that drives the pump to the fluid being pumped. This is achieved by generating an acceleration of the fluid outwards from the centre of rotation of the impeller. As shown in more detail in Figure 3, blades or vanes 300 provided on a rotating disc 301 that is a primary component of the impeller 200, effect a driving of water accepted from the water inlet 126 outwardly from the axis of rotation A'-A'. The velocity of the water that is so generated transfers into an increase in pressure when the outward movement of the water is confined by the pump casing 210 within which the impeller is mounted. The fluid outlet is located on the outer surface 205 of the casing 210 and accepts this pressurised water and directs it to the surface of the blade 105.

In accordance with the teaching of the present invention, the impeller or other means for generating a pressurised water source is integrally provided as part of the consaw and is driven using the same drive mechanism as is used for effecting rotation of the blade. This drive mechanism is typically a belt pulley system with a belt 250 being coupled between the petrol motor- not shown- and a pulley 260 that is co-located with the blade 105 and the impeller 200. In this exemplary arrangement the pulley 260 is provided between each of the blade 105 and the impeller 200.

As shown in Figures 2 and 3 the impeller disc 200 may be coupled to the pulley

260 using a pulley lock nut 320 or other coupling arrangements. In this exemplary arrangement, this pulley lock nut includes a shaft 321 which is engaged with the impeller disc 301 and which is keyed to fit a corresponding nut 322 provided as part of and on a first side 330 of the pulley 260. In this way rotation of the pulley effects a corresponding rotation of the impeller disc. As the two are directly coupled, each will rotate at the same speed. In this arrangement of direct coupling, the disc 301 will typically rotate at the same rate as the pulley. To vary the speed of the disc relative to that of the pulley a gearing arrangement could be provided.

The resultant pressure of the water provided at the blade is resultant from a number of different factors include the speed or rotation of the disc 301 , the number and angle of the vanes 300 and the distance between the outer circumference of the disc and the housing 210 within which it is seated. By designing the housing 210 to provide an increased distance, it is possible to reduce the pressure. The system could also provide for delivery of variable pressure water flows to the blade surface. This could be achieved in a variety of different fashions including for example controlling the volume of water delivered by incorporation of one or more valves either before or after the means for pressurising the water flow so as to allow more or less water to be delivered, or indeed by providing an adjustable nozzle head at the point of delivery to control what is allowed to exit the water supply lines. It will be further appreciated that as the rotation of the impeller is related to the rotation of the blade that if the consaw is operated at slower speeds that the pressure of the water delivered will also be lower.

The pulley 260 is also coupled to the rotating b105, using a coupling mechanism that will be familiar to those skilled in the art. A drive shaft 335 extending from a second face 331 , opposite to the first face 330, couples the pulley 260 to the blade. In this way rotation of the pulley effects a corresponding rotation of the blade 105.

It will be appreciated that a first coupling mechanism between the pulley 260 and the impeller 200 and a second coupling mechanism between the pulley 260 and the blade 105 provides, in the absence of any gearing, for rotation of each of the impeller and the blade at the same rate- that rate being defined by the rate of rotation of the pulley. Each of the first and second coupling mechanism are coaxially arranged with one another and in this exemplary arrangement are provided along the same axis A'-A'. In this exemplary arrangement the first coupling mechanism is provided by the interlock between the locking nuts 321/322 and the second coupling mechanism is provided by the drive shaft 335. These examples of how each of the impeller and the disc are coupled to the pulley is not intended to be construed as limiting the present teaching to these exemplary arrangements.

What is provided by the present inventor is a mechanism whereby the pulley provides a dual feed or drive, a first drive to the blade and a second drive to an impeller or water pump. In the configuration illustrated, couplings are provided on opposite sides of the pulley to each of the means for increasing the water pressure and the rotating blade, i.e. the pulley is arranged between the two. By providing such an arrangement, acceleration of the pulley to increase the drive speed of the blade- such as to improve the cutting rate of the consaw will automatically effect a corresponding and direct increase in the rotation speed of the impeller and hence its output.

The impeller is desirably provided in a sealed unit such that water flow between the inlet 126 and the outlet 127 is confined to the region about the rotating disc 301 and does not leak to other components of the consaw. This modular unit may be provided as a separate sealed unit within the housing of the consaw.

Figures 4 and 5 show a variant to the water feed lines that may be provided. In this arrangement, where the same reference numerals are used for similar components, a single water outlet 405 is provided as part of the means for increasing the water pressure such that pressurised water is provided to one side of the blade only. This may be provided via a moveable or directional outlet, or could be arranged so as to be static in its direction. By increasing the water pressure or by changing the outlet head, it is possible to provide the water in a mist form 410 which may be usefully employed in increasing the area that is dampened by the water supply. As shown in Figure 4 rotating disc or element which is provided as a component of the means for pressuring the water has an axis of rotation parallel to the axis of rotation of the rotating blade, indeed in this arrangement the axis of rotation of the rotating element 200 and the rotating blade 105 is the same, along the line A-A'. In this arrangement the two are co-located at the cutting region of the consaw. In an alternative configuration, the means for pressurising the water supply could be distally located relative to the blade, for example it could be co-located with the engine component of the consaw. Another possible location would be adjacent to the starter handle. The illustrated configuration is however a preferred arrangement in that the drive coupling mechanism is simplified and the ergonomic design of the complete saw unit is also more preferable.

While not shown, the water supply to the pump or other means for pressurising the water flow, may be provided from an integrated water reservoir that is located elsewhere on the consaw. However considering the pressures that will typically be employed and the volume of liquid required to provide these pressures for an extended use period, it is preferable that a supply line from a standalone reservoir be provided. As the water is being provided in a pressurised fashion, this reservoir does not have to have a head height higher than the operation of the saw, in that it can be actively taken from the reservoir as opposed to requiring a gravity feed.

While the fluid described heretofore has been a water supply, it will be appreciated that it is not intended to limit the application of the present invention to water only as certain applications may require the delivery of different fluids other than water to the point of cutting.

It will be appreciated that preferred arrangements of a consaw with integrated pressurised water feed have been described to assist in an understanding of the teaching and benefits derivable from the present invention. By providing a pump impeller arrangement according to the teaching of the present invention which is driven by the same drive means as the rotatable blade of the saw a number of distinct advantages over prior art arrangements is provided. These include a reliable delivery of pressurised water, as required, in a consaw that is both compact and energy efficient. Direct coupling of the blade and impeller with both of these components being driven by the same drive means is such as to obviate any delays between the blade and pump operation, and to provide for regulation of and delivery of water from the pump, as required. It will be appreciated that as the impeller rotates at the same rate as that of the blade that when the blade is used at high speeds, that larger volumes of liquid will be delivered by the impeller than when the blade is operating at lower speeds. This direct and automatic variance of the impeller output ensures that an appropriate volume of water is provided for the cutting operation being conducted. Furthermore, this direct coupling arrangement provides for a very effective operation without waste of water. The device is also advantageously compact and energy efficient by provision of an impeller coupled to the same drive means used to drive the blade. By including means for providing a pressurised water supply to the point of cutting, it is possible to reduce dust levels during use of the consaw.

It will be appreciated that it is not intended to limit the scope of the present teaching to that specifically described as that described is purely provided as an exemplary arrangement and modifications can be provided without departing from the scope of the invention.

The words comprises/comprising when used in this specification are to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers , steps, components or groups thereof.