P/00/0II Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT (ORIGINAL) Name of Applicant: Germans Boada, S.A. Pol.Ind.Can Roses, Avda.Olimpiades, s/n., 08191 RUBI (Barcelona), Spain Actual Inventor: Josep TORRENTS I COMAS Address for Service: DAVIES COLLISON CAVE, Patent & Trademark Attorneys, of 1 Nicholson Street, Melbourne, 3000, Victoria, Australia Ph: 03 9254 2777 Fax: 03 9254 2770 Attorney Code: DM Invention Title: "Improvements to ceramic cutters" The following statement is a full description of this invention, including the best method of performing it known to us:- - la IMPROVEMENTS TO CERAMIC CUTTERS This invention relates to improvements made to manually actuated ceramic cutting machines that include means for movement of a scoring tool over a ceramic tile defining 5 thereupon a breakage or cutting line. The improvements relate generally to a cutting-wheel handle of the cutting machine and to a corresponding cutting-wheel handle holder. 10 BACKGROUND TO THE INVENTION Manual ceramic cutters generally include a base to support a piece of ceramic to be cut and longitudinal guides for a movable assembly of a support on which a folding cutting-wheel handle holder is mounted. A cutting-wheel handle is mounted to the cutting 15 wheel handle holder. Manual ceramic holders of this kind also generally include an actuating lever to press and move the cutting-wheel on the ceramic to form the breakage or cutting line. The cutting-wheel usually comprises a small cutting disk made of tungsten carbide 20 which is assembled to allow for free rotation on the front end of the cutting-wheel handle. The cutting-wheel fitted to the cutting-wheel handle forms a scoring tool which is mounted to the cutting-wheel handle holder for scoring the breakage or cutting line on the piece of ceramic, 25 Usually, the cutting-wheel handle has a cylindrical section having on its periphery a longitudinal flat part on which the end of the actuating lever shall act frontally, retaining it in an operational position with regard to the cutting-wheel handle holder. The end of the actuating lever mentioned is threaded in such a way that when it is inserted into a corresponding hole formed in the cutting-wheel handle holder, it puts pressure frontally 30 against the longitudinal flat part of the cutting-wheel handle, thus immobilising the handle in the operational position relative to the cutting-wheel handle holder.
-2 When performing the scoring of a piece of ceramic, the cutting-wheel is subjected to movement the frequency of which may oscillate according to certain parameters such as the roughness of the surface of the piece of ceramic to be scored and the speed at which the cutting-wheel advances, within the range of between 300 and 4000 hertz. 5 Another aspect to be taken into account is vibration caused by the breakage of the surface vitrified enamel layer in which the characteristic parameter is the size of the split which is produced when scoring the piece. In studies carried out on the vibration of the cutting-wheel, it has been determined that the total spectrum of possible frequencies when 10 the cutting-wheel acts on different materials and types of operation is from approximately 300 hertz to 4 kilohertz, with a high variability at low frequencies (in the region of 1 mm) and low variability at high frequencies (in the region of 0,05 mm or less). The low frequencies propagate through the metallic elements such as the cutting-wheel handle, the actuating lever and the machine frame while the high frequencies attenuate rapidly in the 15 elements of the machine, making them propagate through the air causing the characteristic noise that these machines make in the scoring process. With the use of currently available scoring tools which are composed of a cutting wheel - handle set, a series of disadvantages arises such as; a shortening of the service life 20 of the cutting-wheel, defective scoring on certain materials such as on stoneware where discontinuous scoring has sometimes been reported due to the vibration of the cutting wheel handle, and/or transmission of vibrations to the machine and operator during the scoring process. 25 SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a ceramic cutting machine having a base for supporting a piece of ceramic to be cut, longitudinal guides for guiding a movable assembly of a support on which a cutting-wheel handle holder is 30 pivotably mounted, the cutting-wheel handle holder having a threaded hole for receiving an actuating lever which enables applying pressure with the cutting-wheel to the piece of -3 ceramic and moving the cutting-wheel on the piece of ceramic for scoring a breakage or cutting line in the piece of ceramic, wherein the cutting-wheel handle has at least three longitudinal rebates in its periphery of any geometry, which rebates extend along substantially the entire length of the cutting-wheel handle for reducing a frequency of 5 vibration during scoring of the ceramic piece, and at least one longitudinal plane that is coplanar or rebated relative to the general exterior surface of the handle, for abutment with an end of the lever for immobilising the cutting-wheel handle in the cutting-wheel handle holder. 10 Example ceramic cutters seek to solve or at least alleviate one or more of the above-mentioned problems. Example cutters are simple in their construction and contribute a series of advantages as far as obtaining a continuous scored line is concerned and a reduction in vibration transmitted via the cutting-wheel - handle set to the cutter. 15 At least three longitudinal rebates of any geometry are provided in the periphery of the cutting-wheel handle, to reduce the frequency of vibration during the scoring process. There is also provided at least one coplanar or rebated longitudinal plane with respect to the general exterior surface of the handle for abutment with an end of the lever for immobilising the cutting-wheel handle relative to the machine's cutting-wheel handle 20 holder. The longitudinal rebates extend along substantially the entire length of the cutting wheel handle, thereby providing a considerable reduction in the handle's inertia and cross sectional area when compared to previously proposed ceramic cutters, significantly 25 reducing the frequency of vibrations and their magnitude independently of the specific cross-sectional shape or geometry of the aforementioned longitudinal rebates. As a consequence of the important reduction in the vibration frequency, the cutting tool gains a series of significant advantages such as higher quality of scoring of the 30 ceramic to be cut, a longer service life of the cutting-wheel and distancing of a resonant frequency from the range of operation.
-4 In examples of the invention, the cutting-wheel handle holder has a housing with a transverse cross section corresponding to that of the cutting-wheel handle, thus giving maximum contact surface between both the elements and, together with the fixing carried 5 out by the actuating lever, immobilisation of the cutting-wheel handle relative to the cutting wheel handle holder. This immobilisation reduces the natural frequency of vibration and its transmission to the cutter. BRIEF DESCRIPTION OF THE DRAWINGS 10 The invention is described, by way of non-limiting example only, with reference to the accompanying drawings in which: - Figure 1 is a cross-sectional diagram of a manual ceramic cutter in accordance with an example of the invention. 15 - Figure 2 is a side view of a scoring tool of the ceramic cutter of Figure 1, the scoring tool comprising a cutting-wheel and a cutting-wheel handle. - Figure 3 is a cross-sectional view of the scoring tool of Figure 2. - Figure 4 is a cross-sectional view of part of the ceramic cutter of Figure 1, taken from below a cutting-wheel handle holder which is provided with a hole for 20 receiving the cutting-wheel handle. DETAILED DESCRIPTION As shown in Figure 1, a ceramic cutter in accordance with an example of the 25 invention includes a base (1) for supporting a ceramic piece (2) to be cut and longitudinal guides (3) on which a support (4) is assembled with the ability to move along the guides (3). A cutting-wheel handle holder (5) is pivotably mounted to the support (4). The cutting-wheel handle holder (5) has a hole (51) for insertion of the handle (6) 30 of the cutting-wheel (61) and a threaded hole for the assembly of the end of the actuating lever (52) which serves to immobilise the handle (6) in the hole (51) of the cutting-wheel handle holder (5). Once the lever (52) is assembled on the cutting-wheel handle holder (5) and tightness of the handle (6) has been achieved through actuation of the lever, the inclination of the cutting-wheel handle holder can be varied until the cutting-wheel (61) establishes contact with the piece of ceramic (2) to be scored. The holder (5) is then 5 moved by way of the lever along the path defined by the guides (3) so as to effect scoring of the ceramic piece (2). The improvements introduced to this cutter concentrate basically on the handle (6) of the cutting-wheel (61) and on the cutting-wheel handle holder (5). In accordance with 10 these improvements, the handle (6) has at least three longitudinal rebates (7) which extend along substantially the entire length of the cutting-wheel handle (6), thereby reducing the inertia and the frequency of vibration during the process of scoring the cerarnic piece (2), In the example shown, these longitudinal rebates (7) have a triangular section, 15 although any other section would also be valid since the geometrical aspect does not affect the advantages provided by the definition of the rebates (7) in the handle (6). As usual, the cutting-wheel or scoring disk (61) is assembled on the handle (6), and is able to rotate freely about the corresponding axis (62), 20 The handle (6), as shown in Figure 3, has a longitudinal flat face (8) for bearing against the end of the lever (52), which serves to immobilise the handle (6) in an operational position relative to the cutting-wheel handle holder (5). 25 In the example shown, the hole (51) defined in the cutting-wheel handle holder (5) for insertion of the handle (6) has a transverse cross-sectional shape corresponding to that of the handle (6) which, together with the pressure from the lever (52), results in immobilisation of the cutting-wheel handle (6) with respect to the cutting-wheel handle holder (5). 30 The above example of the ceramic cutting machine has been described by way of -6 example only and modifications are possible within the scope of the invention. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and 5 "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. The reference to any prior art in this specification is not, and should not be taken 10 as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia,