Polishing head

Abstract

The invention describes a polishing head (1) comprising a first flange (2) for connection to a drive shaft; a protective housing (3) comprising an engagement element (31) operably connected to the drive shaft for transmitting a rotational movement to the protective housing (3) about a respective axis (X); a plurality of tool holders (4) positioned so as to protrude below the housing (3); a movement transmission device (5) designed to convert said rotational movement into a swing of the tool holder (4) about its own axis (Y) transverse to said axis (X).

Description

Technical Field

[0001] The invention relates to a polishing head.

[0002] In particular, the present invention relates to a hydraulic polishing head with an oscillating tool clamp.

[0003] These polishing heads are particularly suitable for polishers and / or grinders working with marble, granite, limestone, volcanic stone or any other stone. Background Art

[0004] Currently, polishing heads used for stone grinding and polishing in the prior art generally include a vertical shaft connected to a corresponding motor unit on one side and to a housing on the other side so that the housing rotates at a predetermined speed.

[0005] Between the housing and the part of the shaft that receives the motion there is a fixed reaction flange, which is supported by the housing by means of a bearing, the axis of which is parallel to the axis of the shaft.

[0006] The housing supports a plurality of tool holder elements to which corresponding grinding tools can be connected, and these tool holder elements are controlled to make swinging motions around corresponding axes by means of a mechanical transmission device connected to the above-mentioned drive shaft, so that each grinding tool is provided with a swinging motion around the axis of the corresponding tool holder and a rotational motion around the axis of the drive shaft at the same time.

[0007] There are currently various approaches to the kinematic connection for transmitting the motion from the spindle to the different tool holders.

[0008] For example, a suitably shaped cam (eg a tubular cam) may be used.

[0009] Further, there are embodiments using special connecting rods or levers or rockers which are provided with rollers which interact with corresponding cam means.

[0010] The use of the above-described prior art assembly may result in uneven oscillation of the tool holder due to the shape of the transmission, which may produce dead spots or accelerations when the continuous rotational motion of the drive shaft is converted into alternating motion of the various driven shafts.

[0011] The occurrence of these phenomena has an adverse effect on the grinding process.

[0012] There are also prior art polishing heads which achieve the oscillating movement of the tool holders by means of a motion transmission device consisting of a plurality of gears pivoting on the corresponding tool holders.

[0013] Although the disadvantages of the previously mentioned solution are overcome, this solution can certainly be improved and, conversely, also has some disadvantages.

[0014] A first disadvantage of polishing heads with gear transmission is that they do not allow easy adjustment of the oscillation frequency of the tool holder.

[0015] In fact, in order to be able to adjust this frequency, the gears must be replaced.

[0016] Another disadvantage is that these prior art heads do not always ensure an optimal response to wear.

[0017] Another disadvantage of these prior art techniques is that they do not always ensure adequate optimization of energy consumption.

[0018] In reality, most of the energy supplied is dissipated by friction.

[0019] A further disadvantage is that these prior art polishing heads are not always simple and cost-effective to manufacture.

[0020] Examples of known polishing heads are described in EP 0 510 603 A2 and EP 0 667 210 A1. Summary of the invention

[0021] It is therefore an object of the present invention to provide a polishing head which is able to overcome the above-mentioned disadvantages of the prior art.

[0022] Another object of the present invention is to provide a polishing head which allows the oscillation frequency of the tool holder to be easily changed, so that the performance of the polishing head can be conveniently adjusted according to requirements.

[0023] Another object of the present invention is to provide a polishing head which is able to provide an adequate response in terms of resistance to wear and optimization of energy consumption.

[0024] Another object of the present invention is to provide a polishing head that is simple to manufacture and inexpensive.

[0025] According to the present invention, the above objects and other objects can be achieved by a polishing head comprising the technical features described in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] With reference to the above objects, the technical characteristics of the present invention are clearly described in the appended claims and the advantages of the present invention will become more apparent from the following detailed description, with reference to the accompanying drawings which show purely non-limiting example embodiments of the present invention, in which:

[0027] - Figure 1 is a perspective side view of a polishing head according to the present invention viewed from above;

[0028] - Figure 2 It's from above. Figure 1 A cross-sectional perspective side view of a polishing head;

[0029] - Figure 3 It's from below. Figure 1 A side view of a detail of the polished head;

[0030] - Figure 4 It's from below. Figure 1 A perspective view of a portion of a hydraulic head;

[0031] - Figure 5 is with Figure 4 the same view, this view rotated at an angle sufficient to show other components;

[0032] - Figure 5b yes Figure 5 Scaled enlargement of details;

[0033] - Figure 6 The change of the position of the piston 73 with time t is shown on the rectangular coordinate plane;

[0034] - Figure 7 The position of the piston 74 is plotted over the time t on a rectangular coordinate plane. DETAILED DESCRIPTION

[0035] Reference Figure 1 , numeral 1 generally designates a polishing head manufactured according to the present invention, hereinafter also referred to as head 1 for short.

[0036] The head 1 comprises a first flange 2 for connecting a drive shaft of a corresponding motor arrangement.

[0037] The head 1 according to the invention further comprises a box-shaped housing 3 .

[0038] Advantageously, the housing 3 is connected to the first flange 2 such that the first flange 2 is interposed between the housing 3 and the above-mentioned motor arrangement.

[0039] The housing 3 comprises an upper part 3 ′, a lower part 3 ″ and an inner volume V.

[0040] Advantageously, the upper part 3 ′ and the lower part 3 ″ are fixed to each other by a plurality of bolts.

[0041] Advantageously, the inner volume of the housing 3 is filled with oil.

[0042] Furthermore, the housing 3 comprises an engagement element 31 operatively connected to the drive shaft for transmitting a rotational movement about a corresponding axis X to the housing 3 .

[0043] Advantageously, the engagement element 31 is made on the upper part 3 ′ of the housing 3 .

[0044] The head 1 according to the invention comprises a plurality of tool holders 4 which are mounted on the above-mentioned lower part 3 ″ in such a manner as to protrude from below the housing 3 .

[0045] Advantageously, refer to Figure 1 and Figure 2 , the tool holder 4 is positioned on the circumference of the lower part 3 ″ of the housing 3 .

[0046] Advantageously, the tool holder rotates together with the entire housing 3 .

[0047] Advantageously, the tool holder 4 comprises a grinding tool.

[0048] These grinding tools are designed to engage with the stone and are used to polish and grind it.

[0049] The grinding tools can be removed from the respective tool holders 4 so that they can be replaced at the end of their service life.

[0050] The head 1 also comprises motion transmission means 5 situated in the internal volume V of the housing.

[0051] The transmission device 5 is located in an oil bath.

[0052] The transmission device 5 is designed to convert a rotational movement (imparted to the housing 3 via the drive shaft) into a swiveling movement of the tool holder 4 about a respective Y axis transverse to the X axis.

[0053] Advantageously, each grinding tool is designed to engage with the stone material to polish and grind it by means of a combined movement of rotation about the X-axis and oscillation about the Y-axis.

[0054] The motion transmission device 5 includes a plurality of levers 6 operatively connected to each tool holder 4 , and each lever 6 includes a first lever 61 and a second lever 62 .

[0055] The transmission device 5 further comprises a linear actuation hydraulic device 7 consisting of a first piston 73 and a second piston 74 .

[0056] Advantageously, the hydraulic device 7 comprises a pair of a first hydraulic cylinder 71 and a second hydraulic cylinder 72 .

[0057] Advantageously, the first piston 73 and the second piston 74 are designed to translate in a direction parallel to the axis X inside the first hydraulic cylinder 7 and the second hydraulic cylinder 72 respectively.

[0058] More advantageously, each pair of first 71 and second 72 hydraulic cylinders is positioned close to the respective lever 6 along the X axis.

[0059] The pistons 73 and 74 are movable between a first descending position and a second ascending position, and are in contact with the first lever 61 and the second lever 62, respectively.

[0060] In particular, when the pistons 73 or 74 are in the lowered position, they exert a force on the respective first lever 61 or second lever 62 .

[0061] On the other hand, when the piston 73 or 74 is in the raised position, the corresponding first lever 61 or second lever 62 exerts a force on the piston 73 or 74 .

[0062] The motion transmission device 5 also comprises a hydraulic circuit 8 designed to supply the linear actuation hydraulics 7 .

[0063] The hydraulic circuit 8 is configured to alternately pressurize and depressurize the first pistons 73 and the second pistons 74 so that all the first pistons 73 are in the lowered position and all the second pistons 74 are in the raised position, and vice versa.

[0064] In particular, if Figure 6 and Figure 7 As shown, at each instant t (t1, t2, t3, t4, ...), each first piston 73 pushes on the corresponding first lever 61 of each lever 6 to impart a rotation R to each tool clamp 4, and at each instant t+Δt (t1+Δt, t2+Δt, t3+Δt, ...), each second piston 74 pushes on the corresponding second lever 62 of each lever 6 to impart a rotation R' to each tool clamp 4.

[0065] Advantageously, each repetition of these rotations R and R′ defines an oscillation of the tool holder 4 about the Y axis.

[0066] Reference Figure 6 and Figure 7 , at each instant t, the piston 73 is in the lowered position and the piston 74 is in the raised position, and at each instant t+Δt, the piston 74 is in the lowered position and the piston 73 is in the raised position.

[0067] Reference Figures 3 to 5 The hydraulic circuit 8 comprises a hydraulic pump 81 designed to draw oil from the internal volume V of the housing 3 and introduce it into circulation in the hydraulic circuit 8 .

[0068] Advantageously, if Figure 3 As shown, the housing 3 comprises a toothed portion 32 formed inside the upper portion 3 ′, which is designed to mesh with a toothed wheel 811 of the pump 81 in order to actuate the pump 81 .

[0069] Advantageously, a toothed wheel 811 is mounted on the pump 81 .

[0070] According to further embodiments, the pump 81 is driven by a battery or an electric motor.

[0071] Advantageously, the hydraulic circuit 8 comprises a first branch and a second branch.

[0072] The first branch is connected to the first piston 73 , and the second branch is connected to the second piston 74 .

[0073] When the pump 81 is operated, at least one of the first branch and the second branch is in a pressurized state, while the other branch is depressurized.

[0074] According to another embodiment that is not shown, the hydraulic circuit 8 comprises a hydraulic pump for each branch, making it possible to actuate each branch individually.

[0075] The hydraulic circuit 8 also comprises a distributor 82 designed to receive oil from the pump 81 .

[0076] The distributor 82 includes a valve 822 with an automatic reversal function, which is configured to alternately pressurize the first branch and the second branch.

[0077] In particular, valve 822 with automatic reversal function is configured to pressurize the branch until the grinding tool comes into contact with the stone to be polished and / or grinded.

[0078] When the grinding tool comes into contact with the stone, valve 822 reverses its action, thereby pressurizing the other branch until the same situation as before occurs.

[0079] The first branch and the second branch include a first manifold 83 ′ and a second manifold 83 ″ connected to the distributor 82 , respectively.

[0080] Advantageously, the first manifold 83 ″ and the second manifold 83 ″ comprise an oil flow rate regulator 833 .

[0081] Also advantageously, the flow rate regulator 833 is designed to regulate the oil flow rate inside the hydraulic circuit 8 so that the oscillation frequency of the grinding tool is adjusted as required.

[0082] In particular, the interval Δt between each piston ( 73 , 74 ) from the raised position to the lowered position (or vice versa) depends on the oil flow rate value and can be adjusted by means of the flow rate regulator 833 .

[0083] The upper part 3 ′ comprises a second reaction flange 33 designed to dampen vibrations.

[0084] Advantageously, a second reaction flange 33 is interposed between the first flange 2 and the upper portion 3 ′ of the casing 3 .

[0085] Furthermore, advantageously, the second flange 33 is made of an elastic material.

[0086] The hydraulic circuit 8 includes a filter 84 for removing impurities from the circulating oil.

[0087] The polishing head according to the invention overcomes the above-mentioned disadvantages and brings important advantages.

[0088] A first advantage is that the polishing head 1 designed according to the invention ensures a greatly reduced risk of wear due to its special operating structure.

[0089] In fact, the polishing head 1 is simple to make, allowing the contacts between the mechanical parts to be reduced to a minimum, thus reducing the likelihood of wear and damage.

[0090] Furthermore, minimizing contact between mechanical components greatly reduces friction and, therefore, energy dissipation.

[0091] Therefore, the polishing head 1 of the present invention also has the advantage of providing a product capable of optimizing energy consumption.

[0092] Another advantage of the polishing head 1 according to the invention is that the oscillation frequency can be adjusted without changing the structure of the head.

Claims

1. Polishing head (1), comprising: - a first connecting flange (2) for connecting the head (1) to a drive shaft of a corresponding motor device; - a protective housing (3) of box-shaped structure, comprising an upper part (3'), a lower part (3") and an inner volume (V), the protective housing (3) comprising a coupling element (31) operatively connected to the drive shaft to transmit a rotational movement about its own axis (X) to the protective housing (3), - a plurality of tool clips (4) arranged on the lower part (3") so as to protrude below the protective housing (3); a transmission device (5) arranged in the inner volume (V) of the housing (3) and for transmitting the movement and configured to convert the rotational movement into an oscillation of the tool holder (4) about its own axis (Y) transverse to the axis (X), The transmission device (5) for transmitting motion comprises: - a plurality of levers (6) operatively connected to each of the tool holders (4), each lever comprising a first lever (61) and a second lever (62), the polishing head (1) being characterized in that it comprises: - a linear actuation hydraulic device (7), comprising a first piston (73) and a second piston (74), the pistons (73, 74) being movable between a first lowered position and a second raised position, the pistons (73, 74) being in contact with the first lever (61) and the second lever (62), respectively; - a hydraulic circuit (8) configured to supply the linear actuation hydraulic device (7); the hydraulic circuit (8) configured to alternately pressurize and depressurize the first piston (73) and the second piston (74), so that all the first pistons (73) are alternately in the lowered position and all the second pistons (74) are alternately in the raised position, and vice versa.

2. The head (1) according to claim 1, characterized in that The inner volume (V) of the protective casing (3) is filled with oil.

3. The head (1) according to claim 2, characterized in that The hydraulic circuit (8) comprises a hydraulic pump (81) designed to extract the oil from the internal volume (V) of the protective casing (3) and circulate the oil in the hydraulic circuit (8).

4. The head (1) according to claim 3, characterized in that The protective housing (3) includes an internal toothed portion (32) formed on the upper portion (3'), the toothed portion being designed to engage with a toothed wheel (811) of the hydraulic pump (81) to drive the hydraulic pump (81).

5. A head (1) according to any one of the preceding claims, characterised in that The hydraulic circuit (8) comprises a first branch and a second branch, the first branch being connected to the first piston (73) and the second branch being connected to the second piston (74).

6. The head (1) according to claim 5, characterized in that The hydraulic circuit (8) comprises a distributor (82) configured to receive the oil from the hydraulic pump (81), and the distributor (82) comprises an automatic reversing valve (822) configured to alternately pressurize the first branch and the second branch.

7. The head (1) according to claim 6, characterized in that The first branch and the second branch include a first manifold (83') and a second manifold (83") respectively connected to the distributor (82), and the first manifold (83') and the second manifold (83") include a regulator (833) of the flow rate of the oil.

8. Head (1) according to any one of the preceding claims, characterized in that The upper part (3') comprises a second reaction flange (33) configured to dampen any vibrations.

9. The head (1) according to claim 2, characterized in that The hydraulic circuit (8) comprises a cleaning filter (84) for cleaning impurities in the circulating oil.

10. A head (1) according to any one of the preceding claims, characterised in that The tool holder (4) comprises a grinding tool.

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