[0001] The invention relates to apparatus and methods for guiding cut-off saws. In particular, the invention relates to a guide cradle, and optionally, a guide track, for support and guiding a cut-off saw when in use.

Background of the invention

[0002] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

[0003] Hand-held cut-off saws, sometimes referred to as concrete saws, demolition saws or circular saws, are conventionally used at construction sites, road works, demolition sites and rescue operations to cut through hard materials such as concrete, steel, asphalt, stone, and metal pipes. The cut-off saw has a circular saw blade (also known as cutting wheel) located at the front of the saw which is driven by a petrol engine housed at the rear of the saw. The operational weight of the saw is heavy, typically more than 10 kg.

[0004] In operation, the user supports the weight of the cut-off saw via handles provided on the saw. To cut through concrete flooring slabs for example, the user is typically bent over the saw while supporting and guiding it along a marked line on the slab. It will be appreciated that this process is physically demanding, and prolonged use often leads to injury. Further, it is challenging to guide the cut-off saw steadily along the marked line in order to make precise cuts. The weight and bulkiness of the saw, as well as the vibrations generated by the saw, amplify the jarring that occurs when encountering even minor obstructions or small changes in thickness or hardness of the material.

[0005] In this context, there is a need for improved mechanisms and methods for operating, and particularly for guiding, a cut-off saw.

[0006] It is an object of the present invention to overcome or ameliorate the above discussed disadvantages of the prior art, or at least offer a useful alternative. Summary of the invention

[0007] According to an aspect of the present invention, there is provided a guide cradle for a cut-off saw, comprising: a support bar on which the cut-off saw is supported in use; a fastener assembly for reversibly mounting the cradle to the cut-off saw; and a plurality of wheels at or adjacent a base of the cradle; wherein, when the guide cradle is attached to the cut-off saw in use, the resulting assembly is self-supporting.

[0008] The plurality of wheels provide a plurality of spaced contact points to support said resulting assembly on a ground surface, and at least two of the contact points may be spaced along an axis parallel to a plane of the saw.

[0009] The guide cradle may comprise at least three wheels.

[0010] The guide cradle may comprise four wheels.

[0011] The guide cradle may comprise frame members at each end of the support bar, to which the wheels are mounted.

[0012] Each frame member may be generally arch-shaped, wherein each frame member is mounted to the support bar at or near a crown of the arch, and wherein a wheel is mounted to each base portion of the arch.

[0013] The guide cradle may further comprise one or more reinforcement braces extending between the frame members.

[0014] The fastener assembly may comprise a plurality of upwardly extending bolts receivable within mounting apertures on the cut-off saw.

[0015] The bolts may extend from the support bar, and the position of one or more of the bolts along the support bar may be adjustable. [0016] Each bolt may be housed within an elongate slot in the support bar, along which slot the bolt is movable to adjust the position of the bolt along the support bar.

[0017] Alternatively, the fastener assembly comprises a plurality of slots to receive mounting bolts from the cut-off saw.

[0018] The position of one or more of the bolts in the slots along the support bar is adjustable, and each bolt may be received within an elongate slot in the support bar, along which slot the bolt is movable to adjust the position of the bolt along the support bar.

[0019] When the cut-off saw is attached in use, a blade of the cut-off saw may be positioned forward of the guide cradle.

[0020] According to a further aspect of the invention, there is provided a cut-off saw comprising the guide cradle discussed above.

[0021] According to a further aspect of the invention, there is provided a guide assembly for a cut-off saw comprising: a guide cradle discussed above; and a guide track comprising a guide groove configured to receive at least one of the plurality of wheels in use, such that a blade of the cut-off saw is guided along a cutting path parallel with the guide groove as the cut-off saw attached to the guide cradle is wheeled along the guide track.

[0022] According to another aspect of the invention, there is provided a guide assembly for a cut-off saw comprising: a guide cradle comprising: a support bar on which the cut-off saw is supported in use; a fastener assembly for reversibly mounting the cradle to the cut-off saw; and a plurality of wheels at or adjacent a base of the cradle; and a guide track comprising: a guide groove configured to receive at least one of the plurality of wheels in use, such that a blade of the cut-off saw is guidable along a cutting path parallel with the guide groove by wheeling a cut-off saw attached to the guide cradle along the guide track.

[0023] The guide track may be elongate and dimensioned such that the cutting path is outwardly adjacent an elongate edge of the guide track.

[0024] The guide track may be elongate and configured to be longitudinally connectible to another guide track.

[0025] The longitudinal connection may be via one or more of: a dovetail joint, a mortise and tenon joint, a tongue and groove joint, and a lug received within an aperture.

[0026] According to another aspect of the invention, there is provided a method of guiding a cut-off saw along a cutting path, comprising: mounting the cut-off saw onto a guide cradle, the guide cradle comprising: a support bar on which the cut-off saw is supported; a fastener assembly via which the cut-off saw is reversibly mounted to the guide cradle; and a plurality of wheels at or adjacent a base of the guide cradle; positioning a guide track adjacent the cutting path, the guide track comprising a guide groove configured to receive at least one of the plurality of wheels ("guide wheel(s)"); positioning the guide cradle with cut-off saw mounted thereon onto the guide track with the guide wheel(s) within the guide groove; wheeling the cut-off saw and guide cradle assembly along the guide track such that a blade of the cut-off saw is driven along the cutting path. [0027] The method may further comprise connecting an extension guide track to the guide track to extend the cutting path.

[0028] The guide cradle may be retrofitted to the cut-off saw.

Detailed description of the invention

[0029] The invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figure 1 illustrates a cut-off saw on a guide assembly comprising a guide cradle and guide track according to an embodiment of the present invention, wherein (A) is a close-up view and (B) shows the assembly in use;

Figure 2 is an (A) front perspective view and (B) a plan view of a guide cradle according to an embodiment of the present invention;

Figure 3 is an (A) front elevation view, and (B)/(C) side elevation view of a guide cradle according to an embodiment of the present invention is a rear perspective view of the guide assembly; and

Figure 4 is a (A) plan view and a (B)/(C) perspective view of a guide assembly according to the present invention.

[0030] The drawings illustrate a guide assembly 110, with a guide cradle 2 and guide track 4 for a cut-off saw 100 according preferred embodiments of the invention (Figurel). In embodiments of the invention, the cradle is used to support a cut-off saw for cutting or scoring concrete, though it would be understood that the invention may be used for any cutting device that ordinarily must be supported and steadied by the user. For example, the cradle may be mounted with various types of saws and used on the ground or a platform to cut or score any solid substance, including, but not limited to wood, textiles, metals, plastics and plaster.

[0031] As illustrated most clearly in Figure 1(B), when the guide cradle 2 is attached to the cut- off saw 100 in use, the resulting assembly is substantially self-supporting. Accordingly, the user does not have to bear the weight of the cut-off saw 100 while using it to cut or score the ground/flooring (eg concrete slabs). Instead, the user only has to wheel (by pushing or pulling) the cut-off saw 100 in the desired cutting direction.

[0032] As shown in Figure 2, the guide cradle 2 comprises a support bar 11 on which the cut-off saw 100 is supported in use, a fastener assembly 12 for reversibly mounting the cradle 2 to the cut-off saw 100, and a plurality of wheels 6a, 6b, 6c, 6d, at or adjacent a base of the cradle 2.

[0033] In preferred embodiments, the guide cradle 2 comprises four wheels 6a, 6b, 6c, and 6d so as to be stable and self-supporting when supporting the weight of the cut-off saw. The four- wheeled arrangement also enables the guide cradle 2 with saw 100 attached to be directed in straight line without too much effort and manipulation by the user. However, other suitably stable and sufficiently weight bearing tri-wheeled or multi-wheeled configurations may alternatively be provided. While reference is made to wheels of the guide cradle 2, it should be appreciated that alternative arrangements such as rollers, castors, ball bearings, etc, that provide similar functionality may be utilised.

[0034] The guide cradle 2 comprises frame members 5 at each end of the support bar 11 , to which the wheels 6a, 6b, 6c, 6d are mounted. In one example more clearly illustrated in Figure 3, each frame member 5 is generally arch-shaped, and is mounted to the support bar 11 at or near a crown of the arch. The wheels are mounted to the base portions of the arch.

[0035] The guide cradle 2 further comprises one or more reinforcement braces 18 extending between the frame members 5. In the embodiment illustrated in Figures 2 and 3, each reinforcement brace 18a and 18b comprises an elongate element extending between the frame members 5. In the illustrated embodiments, the reinforcement braces 18a, 18b are attached along a substantial length of each frame member 5, though it would be understood that embodiments of the invention may comprise one or none re-enforcement brace, and that the brace may be in other forms, such as a rod or bar. A semicircular cut-out 21 at the bottom of each reinforcement brace 18a, 18b prevents contact with the blade of the cut-off saw 100 when in use. Depending on the configuration of the cradle and the numbers of wheels (and or the type of wheel substitutes) used in various embodiments of the invention, the cradle may comprise one or more supports bars 11 , one of more frame members 5 and one or more reinforcement braces.

[0036] The fastener assembly of the guide cradle 2 comprises a plurality of slots 12 to facilitate adjustable attachment of the cut-off saw 100. The slots may optionally receive mounting bolts/screws from the saw, or may comprise upwardly extending bolts/screws which are receivable within mounting apertures on the cut-off saw 100. The mounting apertures (not shown) may be pre-existing apertures or may be cut or drilled into a suitable mounting location on the cut-off saw 100, for example on base support feet provided on conventional cut-off saws. Similarly, the mounting bolts/screws (not shown) may be pre-existing bolts/screws on the saw or may retrofitted to a suitable mounting location on the cut-off saw 100, for example on base support feet provided on conventional cut-off saws.

[0037] In preferred embodiments, the support bar comprises three spaced slots 11 to allow for increased adjustability as to where the mounting bolts/screws can be received. Elongated slots further increase the ability of the attachment along the support bar to be adjustable so that the fastener assembly is adaptable to variation in the mounting bolt/screw configuration of the cut-off saw 100. It will be appreciated that alternative fastening mechanisms, eg clamps, latches, etc., may be used to mount (optionally reversibly and/or adjustably) the guide cradle 2 to the cut-off saw 100.

[0038] As illustrated clearly in Figure 1 , when the cut-off saw 100 is attached to the guide cradle 2 in use, the blade 102 of the cut-off saw is positioned forward of the guide cradle, and the guide cradle 2 does not impede normal cutting functionality of the cut-off saw.

[0039] The present invention also provides a guide assembly 110 for a cut-off saw 100 comprising the guide cradle 2 as discussed above and a guide track 4 (See Figure 4). The guide track 4 comprises a guide groove 8 which is configured to receive at least one of the wheels 6a, 6b, 6c, 6d of the guide cradle 2 in use. The guide track 4 is configured such that, by wheeling the cut-off saw 100 and guide cradle 2 assembly along the guide track 4, the blade 102 of the cut-off saw 100 is guided along a cutting path parallel with the guide groove 8. [0040] The guide track 4 may be a single piece or may be assembled from multiple pieces that can be connected together. In the embodiment shown in Figure 4, the guide track 4 is straight, though it would be appreciated the track need not be straight, and can be curved, irregular, angular, or configured into various shapes.

[0041] Accordingly, in contrast to conventional hand-held methods, the user simply wheels (by pulling or pushing) the cut-off saw 100 along the guide track 4 to obtain a straight (or otherwise pre-defined/shaped) cut or score. The present guide assembly 100 therefore improves ergonomics, safety, efficiency and ease of use of the cut-off saw. Cuts may be made faster and with greater accuracy, and repetitive strain injury commonly resulting from conventional handling of the cut- off saw may be prevented.

[0042] As illustrated most clearly in Figure 4, the guide track 4 and guide groove 8 according to preferred embodiments are elongate and dimensioned such that the cutting path is outwardly adjacent an elongate edge 10 of the guide track 4. The cutting path is therefore linear and substantially parallel to the elongate linear guide groove.

[0043] In preferred four-wheeled embodiments of the guide cradle 2, the front and rear wheels on one side of the cradle are both received within the guide groove 8. Preferably, the guide groove 8 and the wheels 6 of the guide cradle are dimensioned for a substantially close fit of the wheels within the groove, to provide a substantially non-diverging cutting path. The guide groove 8 may be defined by two upwardly projecting ribs 9 on either side of the groove 8. The guide track 4 may be provided with two or more guide grooves 8, so that the guide assembly 110 may be adaptable for use with various cut-off saws having different configurations or dimensions.

[0044] In preferred embodiments as illustrated in Figure 4(C), the guide track 4 is configured to be longitudinally connected to another guide track, in order to extend the cutting path. Any suitable reversible interlocking means may be provided, for example, dovetail joints, mortise and tenon joints, tongue and groove joints, lugs 17 received within apertures 19, clamps, latches, etc.

[0045] The guide track 4 is preferably constructed of a lightweight and durable material such as a metal, eg stainless steel, or a rigid polymer. The guide assembly 110 may be provided as a kit comprising a plurality of connectible guide tracks 4 for customisable assembly on-site to suit the particular job requirements.

[0046] It is envisaged that the guide cradle 2, once mounted to the cut-off saw 100, may be retained on the saw, whether or not the saw is always to be used with the guide track 4, since the guide cradle 2 does not impede conventional hand-held functionality of the saw. Accordingly, in some embodiments, the guide cradle 2 may be provided permanently fixed to the cut-off saw, or may be manufactured integral with the cut-off saw. The cradle and guide track of the present invention may be made of any suitable materials.

[0047] The present invention also encompasses methods of guiding a cut-off saw 100 along a cutting path, comprising mounting the cut-off saw 100 onto a guide cradle as discussed above, positioning a guide track 4 as discussed above adjacent the cutting path, positioning the guide cradle 2 with cut-off saw 100 mounted thereon onto the guide track 4 with one or more wheels of the guide cradle within the guide groove 8, and wheeling (or rolling/pulling/pushing) the cut-off saw and guide cradle assembly along the guide track 4 such that the blade 102 of the cut-off saw is driven along the cutting path.

[0048] The method may further comprise connecting an extension guide track to the guide track 4 in order to extend the cutting path, as discussed above. The guide cradle 2 may be retrofitted to the cut-off saw 100, or may be provided with the cut-off saw 100.

[0049] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

[0050] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.

[0051] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.