ES2815499T3 - Pliers for cutting slabs or tiles - Google Patents

Abstract

Engraving nippers for tiles or slabs made of hard material, comprising a pair of lever parts (1a, 1b) articulated to each other, provided on the two opposite sides of an articulation axis (2) respectively with a handle part ( 1a, 1b) and an end head (1a ", 1b") carrying cutting elements in the form of cutting wheels (4a, 4b) with a perimeter cutting edge, said wheels (4a, 4b) being ) fixed parallel to a fixing plane that is perpendicular to a positioning plane of said pair of lever pieces (1a, 1b), characterized in that said end heads (1a ", 1b") have an L shape, so that they define said fixing planes that have a central axis (R) that is offset with respect to said placement plane, and said end heads (1a '', 1b '') have extensions (5a, 5b) opposing that extend according to a direction that joins the centers of said wheels (4a, 4b) to a distance from each other a little greater than the distance between said cutting edges of the wheels (4a, 4b).

Description

DESCRIPTION

Pliers for cutting slabs or tiles

Description

Field of the invention

The present invention relates to pliers for cutting hard tiles or slabs, in particular for cutting and breaking hard facing material.

Previous technique

As is known, for engraving and cutting ceramic, stone or similar material slabs or tiles, there are numerous different tools. Among the simplest are the so-called pliers, that is, tools that can be used with one hand, which provide two opposing cutting elements, pressed towards each other by the respective favorable levers, articulated on a central fulcrum axis.

Conventional pliers are substantially constructed in two pieces articulated together where the cutting elements constitute the two opposite shaped ends (typically wedge or spike shaped, with a more or less sharp cutting edge) of the respective pieces.

This simple and inexpensive solution suffers from some drawbacks. First of all, since the cutting element and the respective lever parts are formed in an integrated manner, they are made of the same material, therefore, it is not possible to optimize the behavior according to the particular characteristics of each element: the The cutting element should have a high hardness, while the levers should have a certain elasticity and resistance to bending. Second, the traditional configuration implies certain limits of operation. In fact, the cutting elements usually have two opposite and rectilinear cutting edges, arranged orthogonally to the main articulation axis of the pliers: this aspect is effective to balance the pliers, but hinders the behavior of the curved cutting, due to the space between the cutting edges and the hinge axis is very small and the pliers contact the edge of the tile as soon as it is angled.

Therefore, improved pliers have been presented on the market, in which said cutting element consists of a separate element, restricted to the ends of the levers by suitable clamping means. In this way, the cutting element can be designed specifically for its purpose, for example in the form of wheels made of very hard material (widia). The wheels also have the advantage that they can be turned as the cutting edge wears.

Examples of pliers with such a configuration are illustrated in Figures 3 to 5 of WO91 / 17964, for example.

The Applicant has further developed this concept by placing the cutting wheels on a slightly inclined plane, for example inclined by 20 °, with respect to the positioning plane of the respective lever pieces, as shown, for example, in the EU registered design number 181110-0005. This configuration is most effective and ergonomic when cutting is required with a component orthogonal to the edge of the tile, for example, a rectangular or semi-circular window along the edge of the tile.

In any case, these latter solutions have in common the fact that the two cutting wheels are arranged in the same plane that is parallel or slightly inclined with respect to the plane of placement of the lever parts of the pliers or, which is the same, perpendicular to the fulcrum axis of the clamp lever parts: this feature serves to prevent the clamp wheels from rotating around their point of contact on the tile when applying lateral force on the clamp body , which would lead to the application of an excessive bending stress in the plane of the wheel, which can cause its breakage (since it is a hard but fragile material).

This constructive limit means that the maneuverability of the pliers in the execution of shaped cuts is not completely satisfactory.

The same document WO91 / 17964 discloses the preamble of claim 1 and in Figures 1 and 2 describes pliers in which the cutting wheels are arranged in a plane parallel to the axis of the fulcrum. However, this configuration, in which the wheels are mounted with their central axis in the plane of symmetry of the pliers, has proven not to be very efficient and exposes the wheels to easy breakage under the action of torsional stress.

Therefore, the applicant has observed that there is room for improvement for this provision.

Summary of the invention

Therefore, the aim of the present invention is to provide a manual cutting tool, such as pliers, which constitutes an improvement over the prior art, especially in terms of maneuverability and accessibility of the tool in the behavior of the shaped cutouts.

This object is achieved by the features mentioned in claim 1. The dependent claims describe preferred features of the invention.

In particular, according to a first aspect, there are provided engraving / cutting pliers for tiles or slabs made of hard material, comprising a pair of lever parts articulated to each other, provided on two opposite sides with a hinge axis, respectively, with a handle part and an end head provided with cutting elements in the form of cutting wheels with a perimeter cutting edge, said cutting wheels being fixed parallel to a fixing plane that is perpendicular to a positioning plane of said pair of lever pieces, in which

said end heads are L-shaped, so as to define said fixing planes arranged offset with respect to said positioning plane, and

said end heads have opposite extensions that extend according to a direction joining the centers of said cutting wheels, up to a mutual distance little greater than the distance between said cutting edges of the cutting wheels.

According to another aspect, the end heads also have raised protective ribs that follow and partially surround said cutting edges of the cutting wheels.

Furthermore, preferably, one of said end heads has a pressing surface for exerting manual pressure, while the other end head has a cutter wheel that can rotate freely. Furthermore, said freely rotatable cutting wheel is mounted on a surface of a respective bearing by means of a through screw coupled with a lock nut arranged on the opposite side of said bearing surface.

According to another aspect, the lever pieces have end-of-stroke closing retainers, which determine a closed configuration in which the cutting edges of said wheels are separated by at least 1.5 mm. Said retainers may be in the form of rubber pads mounted opposite each other on said grip parts.

Brief description of the drawings

Additional features and advantages of the invention will become more apparent from the following detailed description, which is provided by way of non-limiting example and illustrated in the accompanying drawings, in which:

Figures 1, 2 and 3 are respectively front, side and rear elevation views of the pliers according to the invention;

Figures 4 and 5 are top and bottom plan views of the pliers of Figure 1, respectively;

Figure 6A is a perspective view of the pliers of Figure 1, of which Figure 6B represents a partial magnification;

Figure 7 is a perspective view similar to that of Figure 6A, but on the opposite side;

Figure 8 is a perspective view similar to that of Figure 6B, taken from a different line of sight.

Detailed description of a preferred embodiment

The tongs for tiles or slabs made of hard material, such as stone material, are composed in a manner known per se, of two lever bodies 1a and 1b reciprocally articulated on an articulation or fulcrum axis 2. Said two lever bodies 1a and 1b have a generic S-shape and provide, on both sides of the articulation axis 2, a longer part 1a 'and 1b', which acts as a gripping end, and a shorter part 1a '' and 1b '' , which acts as a pressure head. This configuration is what makes it possible to obtain an advantageous lever effect, by manually actuating the longer gripping parts 1a 'and 1b'.

Preferably, between the two extended parts 1a 'and 1b' of the levers a spring 3 or another is provided Similar elastic element, which forces the separation of the two parts, thus keeping the pliers in an open configuration, with the two pressure heads or end heads, more distant from each other.

According to the invention, each of the head parts 1a '' and 1b '' of the two levers has an inverted L-shaped configuration (see Figure 2), so as to define a fixing plane or plane P perpendicular to the plane of placement of the lever bodies 1a and 1b and laterally displaced. In other words, as can be clearly seen in figure 2, the end heads 1a '' and 1b '' define a fixing plane that provides a central axis R that is offset compared to the positioning plane of the lever bodies.

By definition, said central axis R is perpendicular to the support surface and passes through the center of gravity of said support surface.

At each laterally displaced bearing of the two end heads 1a "and 1b", a respective cutting wheel 4a and 4b made of hard material, such as widia, which has a sharp circumferential edge, is supported. The axis of circular symmetry of said cutting wheels 4a and 4b is arranged substantially on the central axis R of the planes.

The wheels 4a and 4b are held in position by a fixing element, such as a screw 4a 'and 4b', which is inserted in the central axis R of the plane and therefore acts as a fixing axis.

Advantageously, the two head ends 1a "and 1b" have respective opposite extensions 5a and 5b, which extend under the wheels 4a and 4b so as to constitute a lateral support element near their cutting edge. Said extensions 5a and 5b essentially constitute extensions of a base part of the fixing planes of the wheels 4a and 4b, which protrude from the profile of the end heads as a short platform of low thickness with substantially straight and partially beveled opposite edges. (As can be seen in Figures 6A to 8). The opposite extensions 5a, 5b extend to a mutual distance little greater than the mutual distance between the cutting edges of the wheels 4a and 4b: in this way, they do not infer with the cutting action (it should be considered that the cutting edge The wheels must be able to penetrate the slab material to a more or less pronounced extent, depending on its compactness), but they are able to avoid an application of bending force to the wheels, as will be explained later. For example, each extension extends to about 1-2mm from the cutting edge of the respective wheel.

Said extensions have the dual function of better supporting the wheels 4a and 4b, as well as making contact with the surface of the slab to be cut, when the longitudinal axis of the tool is inclined with respect to the plane of the slab a cut, avoiding a bending load on the wheels.

The end heads 1a '' and 1b '' also have raised protective ribs 6a and 6b, which follow and surround a part of the circular profile of the wheels 5a and 5b, which extend over a height at least equal to the height of the cutting edge with respect to the fixing plane. Said ribs 6a and 6b have the function of protecting the cutting edge of wheels 5a and 5b from accidental impacts: for this purpose, they are provided on the rear side of the tool, which is located on the opposite side to the offset direction of the tool. central axis R, that is, the side farthest from axis R.

One of the two end heads 1a '' also has an enlargement defining a pressure surface 7, arranged at least in correspondence with an axis passing through the centers of the two wheels 4a and 4b. Said pressing surface 7 is preferably provided with knurling to give it an anti-slip effect. In case it is desired to use a wheel 4b of the tool to perform a sliding cut, pressure will be exerted with the thumb of a user's hand on the pressure surface 7. The pressure of the thumb is directed along the axis that it passes through the centers of the two wheels and will load the farthest wheel that can etch the surface with which it is in contact.

Preferably, for this purpose, the wheel 4b mounted on the end head 1b opposite to which the pressure surface 7 is formed, is mounted in free rotation on the respective axis R. For example, thanks to the fact that the fixing planes are cantilevered with respect to the lever parts of the pliers, a locknut 8 can be provided which is assembled with a screw 4b ', in a part that protrudes below the fixing plane, in such a way as to allow a loose locking of the wheel against its fixing plane. The free rotation of the wheel 4b makes the etching pressure action more effective.

Preferably, the raised protective rib 6a, near the pressing surface 7, ends with a sharp corner 6a 'at the intersection with the axis passing through the centers of the two wheels 4a and 4b. Since the cutting point of the wheels also falls on said axis, the user can advantageously use the sharp corner 6a 'to obtain a line of sight on the cutting point in the slab which, on the contrary, is covered by the same tool .

Finally, the tool according to the invention can provide an inclination locking means L, articulated in one of the two lever parts 1b and with a suitable manipulation end for assembling / disassembling the other lever part 1a, in order to determine or not a mutual lock (in the closed position, as shown in figure 1) between the two lever pieces.

The tool according to the invention can be used in two different ways.

A first procedure is similar to traditional pliers. With the lever pieces 1a and 1b separated in an open position, the slab to be cut is placed between the two opposite cutting edges of the two wheels 4a and 4b and then a cutting pressure is exerted by manual actuation on the two lever pieces 1a and 1b. The pressure is amplified by the prying effect and by the fine cutting edge of the wheels 4a and 4b, so that the slab is cut and fractured. The device is configured in such a way that, even in its fully closed configuration, the two wheels 4a and 4b never come into contact with each other, but instead there is a clearance of, for example, between 1 mm and 1.5 mm: at the moment of the slab fracture, the two wheels are not in contact with each other, which could break them. To make the task more comfortable for the user, the travel closing end of the two lever pieces 1a and 1b is determined by two opposing pads 9a and 9b of sufficiently soft material, such as hard rubber, to cushion the impact. when the fracture of the slab to be cut takes place. Said two opposite pads 9a and 9b are mounted on the respective lever parts of the pliers, close to the spring 3.

In this type of task, if the user also inclines the body of the tool with respect to the plane of the slab, to take advantage of a lever effect, the two extensions 5a and 5b come into contact with the surface of the slab, relieving the bending turning therein and avoiding bending stress on the two brittle wheels 4a and 4b.

The laterally displaced arrangement of the two wheels 4a and 4b, with the fixing axis R, which resides in the cutting plane, displaced with respect to the positioning plane of the lever pieces 1a and 1b, facilitates the intervention of the user when it results It is necessary to carry out a shaped cut, in particular, along lines that have a component perpendicular to the edge of the slab to be cut. In fact, the asymmetry of the cutting plane with respect to the plane of the lever pieces 1a and 1b makes it easier to rotate the tool with respect to the slab and perform the cut within the surface, proceeding from the edge of the perimeter.

A second procedure is similar to that of a traditional engraving tool. Keeping the tool in the closed position, the user can place the free wheel 4b in the plane of the slab to be cut and, pressing the pressing surface 7, causes the wheel 4b to roll on the surface, producing a surface engraving. .

As can be understood from the above description, the tool of the invention perfectly achieves the objects established in the introduction.

In fact, the specific configuration of the end heads equipped with cantilever wheels allows the user to easily make also shaped cuts when using the tool as pliers. The presence of the extensions in the fixing planes of the wheels protects said fragile cutting wheels from bending stresses. Finally, the pressing surface opposite a wheel mounted so that it can rotate offers the possibility of using the tool also as a surface engraving tool.

Claims (6)

1. Engraving pliers for tiles or slabs made of hard material, comprising a pair of lever parts (1a, 1b) articulated to each other, provided on the two opposite sides of a hinge axis (2) respectively with a part of handle (1a, 1b) and an end head (1a '', 1b '') carrying cutting elements in the form of cutting wheels (4a, 4b) with a perimeter cutting edge, said wheels (4a , 4b) fixed parallel to a fixing plane that is perpendicular to a positioning plane of said pair of lever pieces (1a, 1b), characterized in that said end heads (1a '', 1b '') are L-shaped, so as to define said fixing planes that have a central axis (R) that is offset with respect to said positioning plane, and said end heads (1a '', 1b '') have opposing extensions (5a, 5b) that extend according to a direction joining the centers of said wheels (4a, 4b) to a distance from each other a little greater than the distance between said cutting edges of the wheels (4a, 4b). Pliers according to claim 1, in which said end heads also have raised protective ribs (6a, 6b) that follow and partially surround said cutting edges of the wheels (4a, 4b). Pliers according to claim 1 or 2, in which one of said end heads (1a '') has a pressing surface (7) to exert manual pressure, while the other end head (1b '') it has a cutting wheel (4b) that can rotate freely. Pliers according to claim 3, wherein said freely rotatable cutting wheel (4b) is mounted on a surface of a respective bearing by means of a through bolt (4b ') coupled with a locknut (8) arranged on the opposite side of said support surface. Pliers according to any of the preceding claims, in which said lever pieces (1a, 1b) have stoppers (9a, 9b) for the end of stroke, which determine a closed configuration in which the cutting edges of said wheels are spaced at least 1.5 mm apart. Pliers according to claim 5, wherein said retainers (9a, 9b) are in the form of rubber pads mounted opposite each other on said grip portions (1a, 1b).