Structure of a cylindrical grinding wheel for honing heads, particularly for stones, marbles, granite and the like

Abstract

 The present invention relates to a structure of a cylindrical grinding wheel for honing heads, particularly for stones, marble, granite and the like. The cylindrical grinding wheel (1) comprises a supporting element (2), provided monolithically, which extends around the axis of the grinding wheel (1). Said supporting element (2) defines an engagement seat (3), which extends coaxially with respect to the grinding wheel (1), for a wheel-bearing shaft of a honing head. The lateral surface of the supporting element (2) is furthermore rigidly coupled with the abrasive material (6) of the grinding wheel (1) which surrounds it.

Description

[0001] The present invention relates to a structure of a cylindrical grinding wheel for honing heads, particularly for stones, marble, granite and the like.

[0002] As it is known, on some kinds of honing heads for stones, marble and granite, cylindrical grinding wheels are used which are provided with a substantially horizontal axis and which rotate around their own axis and around a vertical axis.

[0003] Usually, such cylindrical grinding wheels comprise a supporting bush which extends around the axis of the grinding wheel and is provided, at said axis, with an engagement seat for accommodating a wheel-bearing shaft of the honing head. The supporting bush is provided, on its lateral surface, with a plurality of dovetail sliding seats which extend parallel to the axis of the grinding wheel, each accommodating a small block which supports a cylindrical sector of abrasive material.

[0004] Such known types of cylindrical grinding wheels feature some disadvantages.

[0005] The particular configuration of the supporting bush and of the small blocks forces the individual formation of the abrasive material in cylindrical sectors on each block, and thus implies high manufacturing costs.

[0006] Furthermore, during the honing process, breakages of the abrasive material occur very often, with a fracture in the region of coupling with the block, which is the most severely stressed region considering the dimensions of the coupling cross section.

[0007] Again due to the configuration and to the materials employed for the supporting bush, which is usually made of bronze, a rapid wear of the engagement seat has been observed, with consequent vibrations which can reduce the life of the honing head and which make necessary several interventions for maintenance.

[0008] Furthermore, due to the fact that the grinding wheel is composed of a composite structure, there is the possibility of an axial sl.ippage of the small blocks, with the cylindrical sectors of abrasive material, from the supporting bush particularly in the case of high operating speeds of the honing head.

[0009] The main aim of the present invention is to eliminate the above described disadvantages, by providing a cylindrical grinding wheel provided with such a structure as to allow a simpler and more economical manufacturing and to offer a greater resistance to the stresses to which it is subject during operation.

[0010] Within the scope of this aim, an object of the invention is to provide a grinding wheel which reduces the interventions for maintenance on the honing heads.

[0011] Another object of the invention is to provide a grinding wheel which simplifies the operations of assembly and disassembly on the honing head.

[0012] This aim, as well as these and other objects which will become apparent hereinafter, are achieved by a structure of a cylindrical grinding wheel for honing heads, particularly for stones, marble, granite and the like, characterized in that it comprises a supporting element made of one piece and extending around the axis of the grinding wheel, said supporting element defining, coaxially to said axis, an engagement seat for a wheel-bearing shaft of a honing head and being provided with a lateral surface rigidly coupled to the abrasive material portion of the grinding wheel.

[0013] Further characteristics and advantages will become apparent from the detailed description of a cylindrical grinding wheel provided with the structure according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

Fig. 1 is a partially cutout perspective view of the grinding wheel according to the invention;

Fig. 2 is a front elevation view of the grinding wheel;

Fig. 3 is a cross section of Figure 2 along the axis III-III;

Fig. 4 is an axial cross section view of the supporting element; and

Fig. 5 is a rear elevation view of the grinding wheel with part of the abrasive material.

[0014] With reference to the figures, the structure of a grinding wheel according to the invention, generally designated with the reference numeral 1, comprises a supporting element 2 which extends around the axis of the grinding wheel and it is made of one piece, e.g. by injection of thermoplastic material in a specific mold.

[0015] The supporting element 2 defines an engagement seat 3 which is coaxial to the axis of the grinding wheel and can be coupled with one of the wheel-bearing shafts of a honing head. For this purpose, the engagement seat is provided, proximate to its end complementary to the free end of the wheel-bearing shaft, with a threading 4 substantially composed of a projection having a rectangular cross section and extending for at least one turn of helix on the surface of the engagement seat and which can be obtained directly during the injection molding of the supporting element.

[0016] Advantageously, the threading 4 will have a direction of threading, on the complementary threading provided on the wheel-bearing shaft, which is opposite to the direction of rotation of said shaft during its operation.

[0017] The supporting element is provided with a substantially cylindrical configuration, with a plurality of undercut expansions 5 which extend radially on its lateral surface. Said expansions are T-shaped, with the base directed towards the axis of the grinding wheel and extend axially for the entire length of the supporting element so as to firmly engage the abrasive material 6 which surrounds it.

[0018] Advantageously, on an intermediate portion of the lateral surface of the supporting element, at least one stiffening ridge 7 is provided, which extends circumferentially on the lateral surface, intersecting the plurality of undercut expansions 5.

[0019] The abrasive material, which is formed directly on the supporting element so as to adhere to its lateral surface when drying, can in turn be made of one piece and be provided, on its lateral surface, with a plurality of grooves 9 which extend radially towards the axis of the grinding wheel.

[0020] The manufacturing and the assembling of the grinding wheel, having the structure according to the invention, are as follows.

[0021] As mentioned, the supporting element 2 is made of thermoplastic material by injection molding and subsequently the abrasive material is cast on the supporting element by using a cylindrical boxing provided with radial dividing walls, said material being composed, e.g., of carborundum, magnesite, magnesium chloride and stabilizing agents with the possible addition of phenolic resins.

[0022] During this forming, the abrasive material makes contact with the lateral surface of the supporting element and, while drying, with the possible passage in an oven if phenolic resins have been added, due to the shrinkage, tightens around the supporting element, tightly adhering thereto. The undercut expansions 5, buried in the abrasive material, increase this cohesion and the stiffening ridge 7 protects the supporting element from eventual deformations due to the tensions of the shrinkage.

[0023] At this point the grinding wheel can be mounted on the wheel-bearing shaft of a honing head simply by making use of the threading 4.

[0024] When the grinding wheel is worn, it can be easily replaced entirely, since the supporting element has a very low cost.

[0025] In practice, it has been observed that the grinding wheel, having the structure according to the invention, fully achieves the intended aim, since it can be obtained with a much lower cost than the grinding wheels of the known kind, and since it has, with respect to the latter, a much greater coupling section of the abrasive material to the supporting element thus having a greater resistance and a longer life.

[0026] A further advantage is that of having an extremely simple and quick assembling, which can be completed with minimal slack between the wheel-bearing shaft and the grinding wheel to contain the vibrations during operation.

[0027] The grinding wheel according to the invention, designed in particular for operations of roughing, semifinishing and finishing, depending on the granulation of the abrasive material, for stones, marble and granite, can also be used for the machining of metallic materials.

[0028] In practice, the materials employed, so long as compatible with the specific use, as well as the dimensions, may be any according to the requirements and to the state of the art.

Claims

1. Structure of a cylindrical grinding wheel for honing heads, particularly for stones, marble, granite and the like, characterized in that it comprises a supporting element made of one piece and extending around the axis of the grinding wheel, said supporting element defining, coaxially with respect to said axis, an engagement seat for a wheel-bearing shaft of a honing head and being provided with a lateral surface rigidly coupled to the abrasive material portion . of the grinding wheel.

2. Structure of a cylindrical grinding wheel, according to claim 1, characterized in that said supporting element is provided with a substantially cylindrical configuration, with a plurality of undercut expansions extending radially on the lateral surface.

3. Structure of a cylindrical grinding wheel, according to claims 1 and 2, characterized in that said undercut expansions are provided with a substantially T-shaped configuration, with the base directed towards the axis of the grinding wheel.

4. Structure of a cylindrical grinding wheel, according to one or more of the preceding claims, characterized in that said expansions extend parallel to the axis of the grinding wheel substantially for the entire length thereof.

5. Structure of a cylindrical grinding wheel, according to one or more of the preceding claims, characterized in that the lateral surface of said supporting element is provided, in an intermediate portion of its length, with at least one circumferentially protruding stiffening ridge.

6. Structure of a cylindrical grinding wheel, according to one or more of the preceding claims, characterized in that said abrasive material is formed monolithically around said supporting element.

7. Structure of a cylindrical grinding wheel, according to claim 6, characterized in that said abrasive material is provided, on its lateral surface, with a plurality of evenly distributed grooves, extending from the lateral surface in the direction of the axis of the grinding wheel.

8. Structure of a cylindrical grinding wheel, according to claim 1, characterized in that said supporting element is made of thermoplastic material.

9. Structure of a cylindrical grinding wheel, according to claim 1, characterized in that said engagement seat is provided, proximate to an end thereof complementary with the free end of the wheel-bearing shaft, with a threading having a screwing direction opposite to the direction of rotation of the grinding wheel.

10. Structure of a cylindrical grinding wheel, according to claim 9, characterized in that said threading is substantially composed of a projection having a rectangular cross section and extending for at least one turn of a cylindrical helix on the surface of said engagement seat.

Drawing