DEVICE FOR SCORING AND FRACTURING CERAMIC TILES

Abstract: The ceramic tile cutter is of the kind comprising at least a bridge guide, provided with device for weakly and heavily fastening the piece of tile to score and fracturing it, respectively, wherein the bridge guide (2) has fixed position at one end and is self adjusted at the other end. Such self adjusting is provided by a suitably shaped cam (40') engaging such bridge guide (2) with its operative contour, which is in the form of an expo­ nential spiral defined by the following formula: b = minimum resistance arm (to be established experimentally); B n = maximum weight arm (to be established experimentally); n = number of (arbitrary) cam segments or α angle sections; α = angle of amenability (to be established experimentally); b; B₁; B₂; B₃;.......B n = Arms of weight; r; R₁; R₂; R₃;.......R n = Points of weight.

Description: The present invention relates to a device for scoring and fracturing ceramic tiles. In the present state of the art devices for scoring and fracturing ceramic tiles had been highly developed both from the point of view of operation and of their manufacturing. Such developing, animated by competition, has abated the real cost and price of these devices particularly of those for occasional use, whereas professional devices for scoring and fracturing ceramic tiles have been less influenced by this developing. Thus professional devices for scoring and fracturing ceramic tiles were rather complex and expansive and it was common opinion that such devices had reached a certain perfection which could not be further improved. This is the case for the arrangement for weakly and heavily fastening the piece of tile to score and fracture, which, in consideration of its thickness, involved each time an adjustment thereof to the tile thickness of the tile. None of the devices known had as sole adjusting arrangement simply a single member including a lever and a cam. In fact as disclosed by GB-A-2 021 036 it is indeed known to provide a device for scoring and fracturing ceramic tiles of the kind comprising at least a bridge guide provided with a device for weakly and heavily fastening a tile to score and subsequently fracture it respectively, the bridge guide having a fixed vertical position at one end; however in this device the adjusting in the whole range of tile thicknesses is not obtained by a self adjusting device, but such arrangement includes an additional control means which provides the complete range only through a double setting, each setting providing an instalment. Even in document US-A-1 297 539, though neither specifying in detail the shape of the cam surface used in the clamp, nor being concerned with the technical field of incising and cutting ceramic tiles, the adaptation of the clamp to the thickness of the workpiece is not automatic since requiring a second rough level adjustment of the cam axis. The invention as claimed is intended to remedy these drawbacks. The inventor has conceived a series of arrangements which from one side maintain the professional level of the tile cutter even increasing its adaptability in use and on the other hand such improvements are the result of simplifications involving an easier manufacturing technology and accommodation of loads. Such accommodation of loads favours a structure lightening which at least at parity of other characteristics results in a decrease of weight comprised between 30%, for models of smaller size to 50% for models of larger size. Reduction substantially of the same order results in the cost. Original and radical improvements have been made to the self adjusting arrangement providing a device for weakly and heavily fastening and fracturing of a tile including a vertically fixed hinged position of one end of the bridge guide. Such self adjusting arrangement is provided by a suitably shaped cam engaging the bridge guide with its operative contour, which is in the form of an exponential spiral defined by the following formula: B 1 to n = bX 1 to n wherein and wherein: b = minimum weight arm (to be established experimentally); B n = maximum weight arm (to be established experimentally); n = number of (arbitrary) cam segments or α angle sections; α = angle of amenability (to be established experimentally); b; B₁; B₂; B₃; .......B n = Arms of the weight; r; R₁; R₂; R₃; .......R n = Points of weight. A so profiled cam provides an easy and control over tiles of various thickness. One way of carrying out the invention is described in detail below with reference to drawings which illustrate two specific embodiments, in which: Figure 1 is a perspective view of a device for scoring and fracturing ceramic tiles according to the present invention, of the kind comprising a scoring tool, pull operable in a direction converging towards the user. The condition of the device is shown with the bridge guide and consequently the driving handle completely lifted, to provide enough space thereunder to receive the thickest tiles, as well as in the attitude for providing off set diagonal cuts, since a loose piece of the gauge, shown in phantom lines, was removed and disposed in an appropriate receptacle adapted also to receive the tools such as the disk or cutter and the like. Figure 2 is a perspective view of a device for scoring and fracturing ceramic tiles in accordance with the present invention, of the kind comprising a scoring tool, push operable in a direction diverging from the user. The condition of the device is shown while a possible user is scoring a tile by one hand, while, with the other hand, he seizes the tile which is of regular thickness. The loose piece for the offset diagonal cut was removed to show the rear parts , and particularly the wedge of steel embodied in the upper wall of the base. Some section lined parts have been broken away for clearness of drawings. Figure 3 is a detailed side view of the user side of the device, comprising the driving handle and the fracturing arms; the driving handle, the bridge guide, the fracturing arms and the tile are shown in different positions, distinguishable in view of the kind of the lines including them. In this figure, the loose piece to make an offset diagonal cut is applied. The attachment means are shown through a breaking. Figure 4 is substantially a repetition of figure 2 but partially in a reduced scale and in the attitude while the user is providing the fracturing effort after scoring. Figure 5 is a graph to design the curve of the cam, driven by the lever which provides either the function of first stage soft seizing, and the heavy grappling to provide fracturing. The starting path includes the subdivision of the field and therefore of the curve in six segments or sections. Referring now to the figures of the drawings, a device for scoring and fracturing ceramic tiles comprises, conventionally, a base 1, possibly embodying a graduated gauge bar 1', from which project: at least a wedge 10 and a rib 10', as well as two uprights 11, 11'; 12 placed at the ends thereof. On the end uprights 11, 11'; 12 is mounted therebetween a bridge guide 2, provided by two parallel rods 2' and 2", wherein a tool 3 is shiftable therealong, a handle 3', a follower 3", in the form of a handle-bar, a substantially rodlike body 30, and at the bottom a disk or cutter 31. Fastened to the bridge guide 2, there is a pressure means 33, provided by a pair of fins 33', 33", while, projecting outwardly, there is a fixed handle 4. Substantially placed above the fixed handle 4, there is a movable handle 40, which is swingable and cooperates with the bridge guide 2. On the upper surface 14 of the base 1, including the wedge 10 and the rib 10', are fastened by adhesive, not shown, the resilient pads 15, 15' of very soft material, to support and retain the tile during scoring and fracturing. Under the base 1 and particularly from the bottom surface thereof, project three or more shoes 16 of resilient material having a high adherence, such as rubber or the like. According to the present invention, on the base 1, the graduated gauge 1' is provided with at least a section 010, which is removable, as a loose piece to be discussed hereunder. The base 1 is made of light alloy, made by a casting process and in it are embedded at least a wedge 10, made of very hard steel, as well as the bottom end 11' of upright 11. In accordance with an essential feature of the present invention, bridge guide 2, provided by two parallel rods 2' and 2", is hingedly mounted, with its end 20 to the upright 11, at the far end from the user, while the end 20' adjacent to the user is urged upward by a spring 6 and may be forced downward by a cam 40', including the lever 40, swingably mounted on the upright 12. It is in such a position that a cam swinging covering the complete thickness range of the tiles as needed by the cutter user, i.e. from 4 mm to 20 mm is obtained. Since resistance opposed to fracturing by the tile varies substantially with the cube of the thickness, the cam 40' is shaped with a profile 44 in the form of a spiral (figure 5). From figure 5 and in part from figure 3 it may be seen that for designing the cam operative profile, which is in the form of an exponential spiral, the following formula can be used: B 1 to n = bX 1 to n wherein and wherein: b = minimum weight arm (to be established experimentally); B n = maximum weight arm (to be established experimentally); n = number of (arbitrary) cam segments or α angle sections; α = angle of amenability (to be established experimentally); b; B₁; B₂; B₃; .......B n = Arms of the weight; r; R₁; R₂; R₃; .......R n = Points of weight. Arguments b and Bn are established experimentally and n is established arbitrarily, in this case as 6; α angle is split into six sections and on each of them is entered, respectively, the arm B which is analytically calculated with said formula. In consideration that the profile of cam may be 8 cm of length, the sixth root of 8 returns 1,4142... Now a short description of operation of the tile cutter will be given. The tile cutter is placed generally on the floor, so that the feet 16 adhere to the same, possibly without wasting it. In stationary condition (figure 1) the bridge guide 2 and, consequently, the driving handle 40 are completely lifted, to provide enough space thereunder to receive tiles 0 of highest thickness (figure 3), and in particular under the press arms or fins 33', 33" or between the same and wedge 10. At this stage, a tile 0, which may be a thin one, 01, e.g. of 4 mm, as shown in phantom lines is accommodated in such interstice. Swinging downward the handle 40 in anticlockwise direction, the bridge guide 2, as well as the press arms 33', 33" engaging such thin tile, assume a position also indicated in phantom lines in figure 3. With thicker tiles 02, 03, e.g. of 10 mm and 20 mm, different corresponding positions apply which are indicated, at dashed and continuous lines, respectively. However, as already explained, the range of swinging of the lever 40 is contained within the grasping limits of the seizer's hand acting between the handle 40 itself and the fixed handle 4. Once the press arms engage the tile or provide such engagement, the thumb 00 of the user's hand engages the seat or indent 040, which is rather close to its fulcrum F. Thus it operates with a relatively reduced arm providing a wanted, drastic, reduced advantage obtained with the handle 40; this avoids anticipated heavy stress of the tile (0, 01, 02, 03) which could accidentally break it. Since such heavy stress is necessary, after scoring for fracturing the tile 02 (figure 4), this may be obtained by maximizing the power arm, i.e. engaging the handles 4 and 40 at their outer ends. At this stage if the tile cutter, in accordance with the present invention, is provided with a push scoring tool 03' (figure 2) the latter is operated in a direction diverging from the user, whereby to score the tile 02; this is made with one hand, while with the other hand, as aforesaid, the tile 02 is seized. The reaction of the operating pushing force, tending to displace the cutter from its proper position is counteracted in part by adherence of feet 16 over the supporting surface and in part acting with the thumb 00 within the indent 040. This management and distribution of the force to be provided is advantageous in providing a perfect scoring even to reduce the fracturing force (figure 4). According to a preferred embodiment of the present invention, for offset diagonal cut to accommodate the tile (0, 01, 02, 03) to be cut, removal of a loose piece 010 of the gauge 1' to register the tile 0 in suitable position is provided. In accordance with another embodiment of the present invention the tile cutter is provided with a receptacle 7, including a lid 7', to receive the loose piece 010, as well as disks or cutters 31' and the like (figure 1). In case that the cutter, as shown in figure 1, is provided with a pull driven tool 3 the force may be even better controlled avoiding overload on the handle 40 which could break the tile 0.

Claims: Device for scoring and fracturing ceramic tiles of the kind comprising at least a bridge guide (2), provided with a device for weakly and heavily fastening the piece of tile (0) to score and fracture it, respectively, wherein the bridge guide (2) is mounted on end uprights (11, 11'; 12) which are fixedly mounted on the base (1) providing a constant distance therebeween and a constant height thereby being able to receive a tile (0) whose dimension along the fracturing line is not longer than the distance between the end uprights (11, 11'; 12), said bridge guide (2) being provided with at least a pair of press arms or fins (33', 33") which are fastened to said bridge guide (2) thereby being movable therewith with respect to the base (1) and in particular to at least a wedge (10) and a rib (10') projecting therefrom, whereby the maximum distance between the top of the wedge (10) and the pressure arm or fin bottom is at least 20 mm, and wherein the bridge guide (2) has been hingedly mounted in a fixed vertical position at one end (20) thereof and is provided with a self adjusting arrangement (F, 40, 40', 040) at the other end (20'), which self adjusting arrangement (F, 40, 40', 040) comprises a suitably shaped cam (40', 44) engaging, at least at the other end (20'), the bridge guide (2) with its operative contour (44). Device for scoring and fracturing ceramic tiles as claimed in claim 1, characterized in that the operative contour (44) of the cam (40', 44) is in the form of an exponential spiral defined by the following formula: B 1 to n = bX 1 to n wherein and wherein: b = minimum weight arm (to be established experimentally); B n = maximum weight arm (to be established experimentally); n = number of (arbitrary) cam segments or α angle sections; α = angle of amenability (to be established experimentally); b; B 1 ; B 2 ; B 3 ; .......B n = Arms of the weight; r; R 1 ; R 2 ; R 3 ; .......R n = Points of weight. Device for scoring and fracturing ceramic tiles, as claimed in claim 1, characterized in that the press arms or fins (33', 33") are fixed to the bridge guide (2) thereby constituting a lever whose fulcrum lies at the one end (20) of the bridge guide (2) and the force fastening the piece of tile (0) being provided by the self adjusting arrangement (F, 40, 40', 040) whereby the load and manual power are minimized, the press arms or fins (33', 33") being placed over the wedge (10) in rather close position to the inner side of a gauge bar arrangement (1') on the base (1). Device for scoring and fracturing ceramic tiles, as claimed in claims 1 to 3, characterized in that an operating handle (40) of the device for weakly and heavily fastening the piece of tile (0) is anatomically shaped so that the user can control the force to be ergonomically provided with both hands in any position, i.e. with any thickess of tile being cut. Device for scoring and fracturing ceramic tiles, as claimed in any of the preceding claims, including a substantially known gauge bar arrangement (1') on its base (1), characterized in that a loose piece (010) is provided whereby the tile (0, 01, 02, 03) may be positioned for offset diagonal cuts. Device for scoring and fracturing ceramic tiles, as claimed in any of the preceding claims, characterized in that the base (1) receiving the tile (0, 01, 02, 03) to be cut is provided with a pair of pads or mats (15, 15') which are stuck on its upper surface (14). Device for scoring and fracturing ceramic tiles, as claimed in any of the preceding claims, characterized in that its scoring arrangement (3, 3', 3" 30, 31) is arranged for push or pull driving or alternately in either direction whereby to provide a definite scoring.

Inventors: CASARTELLI, LUIGI, MONTOLI, EZIO
Applicants: BREVETTI MONTOLIT S.P.A.
Application year: 1988
Main classification: B28D1
IPC codes: B28D1