DESCRIPTION

5 Field of invention

The present invention relates to a tool holder of a manual machine for engraving flat slabs , such as tiles , stone material, glass , or even other materials . In particular, the invention relates to a tool holder equipped with an improved breaking foot .

10 Background art

In the field of installation of floors and tiled coatings , but more generally of flat slabs , devices for cutting flat slabs are commonly used . Among those, manual tile-cutting machines are widely used which use engraving tools carried by tool holder de¬

15 vices , which are in turn slidably mounted on appropriate guides and driven by hand in the engraving phase .

As known, manual tile-cutting machines comprise a basement from which support uprights pro j ect , to which uprights one or more guide rails of the tool holder device are fixed . Such tool holder

20 device is guided according to a pre-set rectilinear path, and allows the engraving tool ( e . g . , a small wheel made of hard material, such as tungsten carbide-based widia) to be precisely driven along the surface of a tile resting on the basement , thus making a surface engraving .

25 Since the engraving is normally made at a certain distance from a reference edge of the tile, and according to an axis orthogonal to or at a dif ferent angle from one of the tile sides , the tile-cutting machines are also equipped with a pivoting square provided with a scale bar, which acts as an abutment profile . The

30 tile is then placed on floating plates of the basement , and one of it s sides is abutted against the pivoting scale bar, so as to place the engraving line where desired .

An exemplary tile-cutting machine , equipped with a pivoting scale bar, is shown in EP 608 , 476 or EP 1 , 545 , 849, in the name of

35 the same Applicant , which are herein incorporated as reference .

After the surface has been engraved, the tile or slab is divided into two parts by a simple pressure, suitably exerted against a rigid rib of the basement , which causes the tile to split along the engraving line . For this pres sure and split action, a suitable member - named breaking foot - suitably arranged integral with the tool holder, is usually used .

According to the most recent technology, the breaking foot is arranged pivoting on the tool holder, for example as illustrated in IT1305649 in the name of the same Applicant and herein incorporated as reference . The breaking foot is mounted in the lower part of the tool holder, and it is kept raised in a home position during engraving while it is lowered in an operating position when splitting is to be performed by manually acting on the tool holder .

Other known breaking foots are disclosed in WO2021 /119777 and US2009/ 0145416 wherein grooves and recesses are provided with the purpose of lightening the piece and making it more flexible .

In the use of these machines , it has been noted that , although the presence of the pivoting scale bar, very often the operator is not able to exploit it because he does not have precise linear and angle measurements to correctly abut the tile against the scale bar . There is then another case wherein using the pivoting scale bar appears not to be appropriate , i . e . , when the tile must be cut from corner-to-corner . Ideally, the engraving should be made at 45 ° with respect to one side of a square tile : actually, due to the tile inaccuracies , a 45 ° line would risk not intercepting exactly the two opposite corners of the tile , especially if it is large .

To make the engraving according to the desired axis , the operator is therefore used to marking - with a pencil or other tool - two extreme point s of the engraving line , after temporarily placing the tile in the installation site and sighting the other surrounding tiles or masonry lines to match . After this marking, the tile must be placed on the machine basement so as to make the two marked extreme point s fall in correspondence with the engraving line, operation which is however complicated . In fact , sighting the marking point s with the sliding guide of the tool holder turns out to be very inaccurate , because the guide is arranged several centimetres above the tile . Using the same engraving tool as a reference, by moving the tool holder above the two marking point s , is inconvenient and equally inaccurate because the tool is set below the tool holder, and it is not clearly visible to the operator . The problem is amplified in push-type tool holders because the tool is in the front of the tool holder, completely hidden from the view of the operator which stands in the rear position to perform the engraving .

The Applicant has already offered a solution to these problems , by providing a rectilinear luminous line on the engraving axis , as described in IT102003901132350 . This patent document taught the use of a laser source, installed in the basement or the tool holder, apt to emit a laser beam at the height of the tile plane, which illuminates a marker line in correspondence of the path of the engraving tool : in this way it is sufficient to arrange the two extreme points of the marking on the illuminated line and then proceed with the engraving .

However, the use of this solution involves some drawbacks . First , the laser beam emitted by small battery-powered sources maintains an acceptable quality if the line to be illuminated is of modest length; however, if the engraving line is particularly long - as in the case of large tiles now commonly available on the market - the beam fans out at the distal end and is unable to produce a thin line, thereby losing accuracy . Furthermore, since most of the time the use of tile-cutting machines takes place near or inside construction sites , the laser device is exposed to dust , debris ( such as lime , sand, or cement ) or fluids ( such as paints , corrosive agents , or glues ) , which can damage or partially obstruct the laser source, thus reducing it s ef fectiveness and visibility . Finally, during transport and use of the tile-cutting machines , any impacts or falls can loosen the laser source in it s housing, resulting in a laser beam unstable or even no longer aligned with the engraving line .

It is to be noted that this last accuracy problem is inherent of a solution based on indirect indication, namely : a line from a laser source indicates the theoretical tra jectory that the engraving tool is expected to travel, but not the actually travelled one (net of construction inaccuracies or plays due to wear ) .

The Applicant has set itself the ob j ective of improving the tool holder, to solve said drawbacks .

Summary of the invention

The ob ject of the present invention is therefore to provide a tile-cutting machine being so arranged so as to obtain correct alignment of a tile with respect to an engraving line of an engraving tool, without resorting to laser lighting . In particular, an arrangement is desired to be offered which gives a direct and not indirect indication of the position taken by the engraving tool along the engraving path .

This obj ect is achieved by means of a tool holder for a manual tile-cutting machine , having the features set out in essential terms in the attached claims .

In summary, the expedient offered is that of providing a tool holder wherein the breaking foot is equipped with special markings allowing the path of the proximal engraving tool to be visually identified and traced .

In particular, according to a first aspect of the invention it is supplied a tool holder for a manual tile-cutting machine, comprising a main sliding body equipped with an actuation handle extending rearward, an engraving tool mounted in a front lower part of said main body arranged on a longitudinal axis of the tool holder, a breaking foot mounted pivoting in a rear lower part of said main body, wherein the breaking foot has visible viewfinder means which mark a center axis of the breaking foot , aligned with said longitudinal axis of the tool holder, the visible viewfinder means comprising at least one main marker in the shape of a rib or a groove less than 2 mm, preferably 1 mm, wide .

According to a preferred aspect , said visible viewfinder means also comprise at least one auxiliary marker element . According to a variant , the main marker element can comprise a groove extending on an annular perimeter of said breaking foot , in correspondence of said center axis .

Optionally, said main marker element also comprises a colour O-ring installed or co-moulded in said groove .

The auxiliary marker element preferably consist s of a pair of direction arrows pointing towards said center axis .

Optionally, said main marker element is a rib in the form of a cusp-shaped protrusion which is part of a symmetrical insert arranged on said center axis of the breaking foot . In this event , preferably, said symmetrical insert is made of an elastomeric material moulded onto said breaking foot .

Optionally, said main marker element is a thin stripe painted or applied as a decal on said center axis of the breaking foot . Brief description of the drawings

Further features and advantages of the invention will anyhow become more evident from the following detailed description of some preferred embodiment s , given by way of non-limiting example, and illustrated in the attached drawings , wherein :

Fig . 1 is a perspective, partially interrupted, view of a tile-cutting machine according to the invention, with the tool holder in the splitting position;

Fig . 2 is a perspective view of only the breaking foot shown in Fig . 1 ;

Fig . 3 is a view similar to that of Fig . 1 with the tool holder in the engraving position;

Figs . 4-7 are front elevation views of different embodiment s of the breaking foot of Fig . 2 ; and

Fig . 8 is a photographic perspective view of a further embodiment of the invention .

Detailed description of preferred embodiments

A manual tile-cutting machine A is shown in Figs . 1 and 2 , having, in a manner known per se, a basement 1 and two uprights , a distal end upright 3a and a proximal end upright (not shown ) at the proximal end 3b, between which a guide bar 4 extends supporting and guiding a tool holder . A scale bar 2 is also mounted pivoting on the basement 1 , apt to function as an adjustable abutment for tiles or slabs , with it s axis of rotation located near the distal end upright 3a .

The tool holder has a main body 5 , suitable for precisely sliding on the bar 4 , which carries an engraving tool V below - typically a hard metal wheel, which can just be glimpsed in Fig . 3 , in the front lower part of the tool holder - and is provided at the top with a grasp handle 6 extending rearward, through which the operator can act for the action of engraving .

In the lower part of the tool holder body 5 , backward to the engraving tool V, a breaking foot 7 is also provided, typically in the form of a prismatic body preferably having an L-shaped cross section . The breaking foot 7 is mounted pivoting on the tool holder body 5 , to be able to move from a raised position illustrated in Fig . 3 , during the engraving phase of the tool holder, to a lowered position illustrated in Fig . 1 , which allows it to descend below the engraving tool V during the phase of splitting the tile .

As is known, the manual tile-cutting machine provides for a tile to be placed and held on the basement 1 , abutting against the scale bar 2 previously arranged at a desired angle .

In a machine such as the one illustrated, of the ' push ' type, the tool holder is pushed with pressure by the operator ( standing on the foreground side in Figs . 1 and 2 ) , driving the tool holder from a position close to him/her ( i . e . , near the proximal end upright - not shown ) to a position away from him/her, in the proximity of the distal end upright 3a where the scale bar is installed . During this action, the engraving tool V engraves the underlying tile (not represented) .

The splitting phase is conducted at the end of the engraving phase . Once the tool holder has been trans ferred to the front end of it s stroke , the tool V can be pushed beyond the edge of the tile into a recessed terminal area, thus making it to descend below the tile plane and putting the breaking foot 7 under pressure against the tile to produce a first split . Then, the breaking foot 7 can be lowered to the position of Fig . 1 and the tool holder is progres sively brought into back positions , where further splitting pressures are applied along the engraving line, until complete separation of the tile into two parts .

In many cases , the engraving position with respect to a corner or a side of the tile, as well as the engraving angle, can be clearly determined a priori , and can be set with the scale bar 2 , according to techniques known to those skilled in the art .

However, as previously illustrated in the introduction, there are situations wherein the angle and the measurement cannot be precisely determined : therefore, the tiler simply marks two extreme points on the tile - during a simulation of laying down the tile - which represent the ends of a straight line along which the engraving must be made .

In these situations , the tile must be laid on the basement 1 , trying to make the extreme point s marked on the tile fall in correspondence with the theoretical rectilinear path of the tool V .

To this end, according to the invention, the tool holder body 5 is equipped with an improved breaking foot 7 , provided with viewfinder means arranged in perfect alignment with the engraving tool V placed right in front of them .

In Figs . 2 , 4 and 5 some embodiment s of a breaking foot 7 according to the invention are illustrated in detail .

The breaking foot device 7 is , in a manner known per se , substantially prismatic in shape , with an L- or T-shaped sections (as illustrated) to define raised portions 7a and 7b arranged orthogonal to each other and therefore suitable for defining split feet (which abuts on the tile ) in the two positions ( raised and lowered) which the breaking foot 7 can as sume .

Preferably, at least the transversal thicknes s of the raised portions 7a and 7b is narrowed in a center area and widens at the ends 7 ' , so that the points of contact with the tile are spaced apart from the center axis ( in correspondence of which the engraving line of the tool falls ) and an ef fective bending ef fect can be exploited, which facilitates the opening of the underlying tile along the engraving line . The breaking foot 7 also has a fork 9 , provided with two aligned holes 9a, by means of which it is mounted pivoting on the tool holder . The holes 9a house then a pivoting pin (not shown ) which defines a pivoting axis of the breaking foot arranged cros swise to the engraving axis . Additional holes 10 can also be provided, apt to hook elastic elements ( springs ) known per se , which help to hold the breaking foot 7 in a desired position ( raised or lowered) .

The breaking foot is made , normally by moulding, of a plastic or elastomeric material , strong enough to withstand the splitting pressure, and with a surface finish suitable for not dirtying or scratching the surface of the tiles .

According to the present invention, along the center axis of the breaking foot , viewfinder means are provided, which will be better described hereinafter, aligned with the engraving tool V mounted just in front of them on the tool holder 5 . It should be noted that in this context , median axis means the axis of symmetry of the breaking foot 7 , which is longitudinally aligned with the engraving axis defined by the engraving tool V .

In the embodiment illustrated in Fig . 2 , a notch or groove

100 is formed on the center axis of the breaking foot , extending on the entire annular perimeter, within which a marker element

101 is housed, for example a coloured O-ring (e . g . , red, blue , or green ) manufactured separately and mounted in the groove 100 , or directly co-moulded in the groove 100 . For the groove and the relative O-ring to perform the desired function correctly, their thickness or width ( i . e . , the dimension in the cros swise direction to the longitudinal engraving axis ) must be minimal , for example les s than 2 mm, preferably less than 1 mm .

Since the groove 100 is formed on the breaking foot center axis , the marker element 101 visually identifies a corresponding engraving plane of the engraving tool V very well . The marker element 101 thus acts as viewfinder means , clearly visible even to an observer standing behind the tool holder - in the engraving operating position - for any position the breaking foot 7 takes .

In the embodiment of Fig . 4 , the breaking foot 7 further has a main marker element on the center axis , for example only a shallow groove 102 , as well as an auxiliary marker element helping to better visualize the main marker element 102 , such as a pair of direction arrows 103 pointing towards the center axis . The direction arrows 103 may be formed as bas-relief s in the thickness of the breaking foot material or may be made as decals or by painting .

In the embodiment illustrated in Fig . 5 , the viewfinder means are obtained by moulding above the breaking foot a main marker element in the form of a cusp-shaped insert 104 , for example made of an elastomeric material . The cusp-shaped insert 104 preferably has a symmetrical shape and ends with a cusp-shaped rib 104 ' arranged on the center axis of the breaking foot 7 .

The extension of the cusp-shaped insert 104 with respect to the pivot axis is anyhow les s than the distance between the contact ends 7 ' and the same pivot axis , so that no interference can occur between the cusp-shaped rib 104 ' and the underlying tile while using the tool holder .

The combination of main and auxiliary marker elements can also be dif ferent from that described above, being able to be combined as preferred, for example also as shown in Figs . 6 and 7 .

A simplified shape of the marker element , as the one shown in Fig . 8 , can also provide for a simple painting or decal application of a thin stripe 105 ( les s than 2 mm, preferably 1 mm, wide ) along the annular perimeter of the breaking foot , on the center axis ; for the painted stripe, a colour for example which creates a visible contrast with the breaking foot colour (e . g . , white on red, yellow on black, or red on light blue ) can be used, or a light-reflecting paint . Although not having a significant thickness , the painted stripe is to be equally considered as a marking rib, as it serves the same function as the ribs/grooves indicated above . In the proximity of the thin center stripe, direction arrows 106 can be provided - using the same painting technique or decal application - which better focus the user ' s attention on the main marker element ; as represented in Fig . 8 , the direction arrows 106 can preferably be provided on two orthogonal faces of the breaking foot .

As can be clearly understood from the description above , the tile-cutting machine equipped with the breaking foot according to the invention allows to perfectly achieve the ob jects stated above .

In particular, thanks to the innovative configuration of the breaking foot , provided with viewfinder means in the form of ribs or grooves , pos sibly as sisted by auxiliary marker means such as arrows , the operator is allowed to visually identify the position of the engraving line ef fortlessly . In fact , since the viewfinder means are located on the breaking foot , which is in the rear lower part of the tool holder, they not only are visible to the operator standing on the rear part of the tool holder, but they also are very close both to the actual engraving tool and to the tile surface : therefore, by sighting the viewfinder means with the marks which the operator has previously drawn on the tile , it is possible to align the same on the desired engraving line with no difficulties .

It should furthermore be considered that the viewfinder means are integral with the tool holder near the actual engraving tool; therefore , they provide a direct indication of the engraving line position, which is not affected by any errors or plays when mounting the tool holder on the tile-cutting machine .

Finally, with the inventive solution it is possible to benefit from the same advantageous result s even on tile-cutting machines of the prior art , by simply replacing the tool holder, without thus making modifications to the basement part .

However, it is understood that the invention should not be considered as limited to the specific embodiments illustrated above , but that dif ferent variants are pos sible all within the reach of a person skilled in the art , without thereby departing from the scope of protection of the invention itself , which is only defined by the following claims .

For example, the main and auxiliary marking means may also have dif ferent shapes or be made of dif ferent materials , while continuing to serve the main function of making a center line or plane falling in correspondence with the engraving line of the engraving tool visually evident on the breaking foot .