Technical Field

The present invention relates to a method for regenerating diaphragm petals. Background Art

Diaphragm retaining devices are known, which are generally provided with a frame supporting in rotation a plurality of movable elements called petals.

The petals are each movable around a relevant axis of rotation between an opening position wherein they define a diaphragm passage opening and a closure position wherein they completely obstruct the passage opening.

The petals are further movable to at least one intermediate position, wherein they are brought close to the center of the diaphragm, and allow objects to be retained in order to perform further machining thereon.

Figures 1 and 2 show, as an example, a diaphragm D provided with a plurality of concentric petals P in the opening position (Figure 1) and in the closure position (Figure 2).

A diaphragm petal is shown in greater detail in Figure 3.

The petal P comprises a hole F through which the petal itself is associated with the frame T of the diaphragm D and which defines an axis of rotation R1 around which, in use, the petal P is movable between the opening position and the closure position.

The petal P also comprises a first surface SI which, in the opening position partly defines the passage opening, and a second surface S2 which is arranged in contact with the first surface SI of an adjacent petal and sliding thereon between the opening position and the closure position.

A vertex V is defined between the surfaces SI, S2 which, in the closure position, is arranged substantially at the center of the diaphragm D.

In fact, one of the advantages related to the use of diaphragms is the possibility to completely occlude the passage opening.

However, as a result of a prolonged use, frictional forces may cause wear of the surfaces SI, S2 and the formation of a beveled vertex.

As a result, in the closure position, the worn petals are unable to completely close the passage opening and, at the same time, in the opening position, cracks are created between one petal and the adjacent one, which cracks communicate with the passage opening, thus risking jeopardizing the proper function of the diaphragm.

For this reason, petals must be replaced with new ones. However, as can be easily appreciated, this leads to an excessive increase in production costs which affects the customers’ retail price of the finished products, especially in view of the fact that even wear of only a few hundredths of a millimeter can jeopardize the proper functionality of the diaphragm.

Description of the Invention

The main aim of the present invention is to devise a method for regenerating diaphragm petals which allows avoiding excessive replacement jobs of the petals of a diaphragm.

Another object of the present invention is to devise a method for regenerating diaphragm petals which allows ensuring proper functioning of the relevant diaphragm.

A further object of the present invention is to devise a method for regenerating diaphragm petals which allows keeping production costs down.

Another object of the present invention is to devise a method for regenerating diaphragm petals which can overcome the aforementioned drawbacks of the prior art within the framework of a simple, rational, easy and efficient to use, as well as inexpensive solution.

The aforementioned objects are achieved by the present method for regenerating diaphragm petals having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a method for regenerating diaphragm petals, illustrated by way of an indicative, yet non-limiting example, in the attached tables of drawings in which:

Figures 1 and 2 are axonometric views of a diaphragm not covered by the present invention, in two different operating positions; Figure 3 is a plan view of a diaphragm petal;

Figures 4-6 are plan views of a petal to be regenerated at different phases of the method according to the invention;

Figures 7-9 are axonometric views of a petal bushing at different phases of the method according to the invention.

Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally denotes a diaphragm petal.

The method according to the invention first comprises a phase of supply of at least one petal to be regenerated 1.

The petal to be regenerated 1 comprises a hole 2 as sociable with a frame T of a diaphragm D. The hole 2 defines an axis of rotation R1 around which, in use, the petal to be regenerated 1 is movable between an opening position, wherein it partly defines a passage opening of the diaphragm D, and a closure position, wherein it partly obstructs the passage opening.

In accordance with the embodiment shown in the figures, the axis of rotation R1 is substantially perpendicular to a lying plane of the petal to be regenerated 1. Specifically, the petal to be regenerated 1 comprises a removable bushing 3 defining the hole 2. The petal to be regenerated 1 also comprises a housing seat 4 within which the bushing 3 is fitted (Figure 4).

As a result of prolonged use, the petal to be regenerated 1 is provided with: a first worn surface 5 defining, in use, at least part of the passage opening; a second worn surface 6, contiguous to the first worn surface 5 and, in use, associated with the first surface of an adjacent petal in a sliding manner; a worn vertex 7 located between the first worn surface 5 and the second worn surface 6.

The method then comprises a phase of grinding the first worn surface 5 and the second worn surface 6 to obtain a first ground surface 8, a second ground surface 9 and a new vertex 10 located between them.

In the petal to be regenerated 1 thus ground, the spacing between the new vertex 10 and the axis of rotation Rl, indicated in the figures by the reference numeral d2, is less than an original reference value, indicated in the figures by the reference numeral dl (Figure 5).

In fact, the original petals P are initially specially machined so that the spacing between the vertex V and the axis of rotation R1 is equal to a predefined reference value (dl, Figure 3).

The grinding phase comprises a removal of part of the material of which the petal to be regenerated 1 is made and results, therefore, in a setback of the new vertex 10 of the petal to be regenerated 1 with respect to the original axis of rotation Rl. Consequently, this operation results in a reduction of the spacing defined between the new vertex 10 and the original axis of rotation Rl.

In this regard, it should be specified that, in accordance with the embodiment shown in the figures, the ground surfaces 8, 9 are transverse to a lying plane of the petal to be regenerated 1, preferably, they are perpendicular to the lying plane of the petal to be regenerated 1. In addition, the ground surfaces 8, 9 are transverse to each other and the new vertex 10 is defined by the intersection of the ground surfaces themselves.

Therefore, the new vertex 10 is developed along a substantially straight direction which is parallel to the axis of rotation Rl. The spacing is then measured as the distance between the direction of development of the new vertex 10 and the axis of rotation Rl.

It cannot, however, be ruled out that the new vertex 10 develops along a curvilinear or irregular direction, depending on the shape of the ground surfaces 8, 9. In such a case, the spacing is measured as the distance between the farthest point of the new vertex 10 and the axis of rotation Rl.

Thus, the method also involves a phase of definition of a new hole 11 defining a new axis of rotation R2 wherein the spacing between the new vertex 10 and the new axis of rotation R2 corresponds to the original reference value (dl, Figure 6).

The new axis of rotation R2 is substantially parallel to the original axis of rotation Rl. Consequently, the new vertex 10 is substantially parallel to the new axis of rotation R2. More specifically, the original vertex V and the new vertex 10 lie on a plane substantially perpendicular to the lying plane of the petal to be regenerated 1 and substantially parallel to the plane to which the axes of rotation Rl, R2 belong.

In more detail, the phase of definition comprises the following steps: removal of the bushing 3 (Figure 7) from the petal to be regenerated 1 ; supply of a blank bushing 12 (Figure 8); drilling of the blank bushing 12 to obtain a new bushing 13 provided with the new hole 11 (Figure 9).

The blank bushing 12 is of a type known to the industry engineer and, in accordance with the embodiment shown in the figures, is pre-drilled. It cannot, however, be ruled out the use of a blank bushing 12 without pre-drilling.

The method will now be described in more detail in the succession of the related phases.

The method initially involves a phase of positioning the petal to be regenerated 1 with respect to a predefined position.

Specifically, the method according to the invention is performed on at least one automated processing machine, known to the field technician, and the petal to be regenerated 1 is placed where a relevant adequate seat is located.

In accordance with the embodiment shown in the figures, in the predefined position, the petal to be regenerated 1 is positioned with the spacing substantially parallel to a substantially horizontal Cartesian axis X.

Specifically, in accordance with a preferred embodiment, the predefined position is determined according to the position of the housing seat 4 of the bushing 3. For this purpose, the removal step of the bushing 3 is carried out prior to the phase of positioning.

The housing seat 4, in fact, is of predefined geometry and, precisely because of the presence of bushing 3, is not subject to wear and, at the same time, is not subject to grinding operations.

More in detail, the predefined position is exploited to carry out with the utmost precision the movement and actuation of the relevant machining tools, as will be better explained later in this disclosure. The method then comprises a phase of retaining the petal to be regenerated 1 in the predefined position.

Specifically, the phase of retaining the petal to be regenerated 1 is carried out at a position located between the hole 2 and the worn vertex 7.

In accordance with the embodiment shown in the figures, the petal to be regenerated 1 comprises at least one pivot 14 defined at an intermediate position between the hole 2 and the worn vertex 7 and adapted to operate in conjunction, in use, with the actuation means for actuating the diaphragm D.

The pivot 14 develops substantially perpendicularly to a lying plane of the petal to be regenerated 1.

The phase of retaining is performed where the pivot 14 is located.

Conveniently, the phase of retaining comprises at least a first step of blocking the petal to be regenerated 1 against shifts along the three Cartesian axes.

In accordance with the preferred embodiment, the first step of blocking is performed by means of anchoring the pivot 14. As an example, the pivot 14 is fitted inside a relevant housing defined on the working machine.

The phase of retaining also comprises at least a second step of blocking the petal to be regenerated 1 against a rotation around an axis passing through the pivot 14.

In detail, the second step of blocking is carried out by clamping the petal to be regenerated 1.

The phase of retaining ensures that the predefined position is maintained and the subsequent phases are carried out in a very precise and accurate manner.

As a result of retaining, the method comprises the phase of grinding.

The phase of grinding comprises at least one step of moving at least one milling tool along a predefined path.

Specifically, the milling tool is rotatable on itself and, in the relevant movement along the predefined path, is placed in contact with the first worn surface 5 and with the second worn surface 6.

In this regard, it should be specified that, in order to ensure proper operation of the diaphragm D, the phase of grinding is carried out so that the first ground surface 8 and the second ground surface 9 are substantially parallel to the first surface SI and to the second surface S2 of the original petal P, respectively.

The predefined path is, in fact, processed according to the first surface SI and to the second surface S2 of the original petal P.

Specifically, as stated above, during the phase of positioning, the petal to be regenerated 1 is placed along the Cartesian axis X and the predefined path is shifted along the Cartesian axis X by a grinding value with respect to an original path.

In this regard, it should be specified that the original petal P initially undergoes grinding of the first surface SI and of the second surface S2 in order to remove any machining deburring.

Specifically, the coordinates of the predefined path are varied with respect to the original path, at each of its points, only with respect to the Cartesian axis X of the grinding value, so that the pattern of the path itself remains unchanged and the milling tool is brought closer to the worn surfaces 5, 6.

During the phase of grinding, therefore, the path of the milling tool remains substantially unchanged but the relevant position is shifted along the Cartesian axis X to come in contact with the worn surfaces 5, 6.

In this regard, it should be specified that in the figures, in order to better illustrate the phase of this method, the amount of wear and the amount of removed material as a result of grinding are oversized with respect to the profile of the original petal P. However, as can be easily appreciated, the actual amount of both wear and removed material during grinding is on the order of a few hundredths of a millimeter.

Advantageously, the phase of grinding may comprise a repetition of the step of moving the milling tool. In order to avoid excessive material removal, in fact, the predefined path can be varied by infinitesimal values each time so that the phase of grinding can be stopped as soon as the new vertex 10 is defined. For this purpose, the phase of grinding also comprises a step of verification to verify the amount of removed material.

In accordance with the preferred embodiment, the step of verification is carried out by means of visual inspection after each step of movement. In this case, an operator visually checks whether the worn surfaces 5, 6 have actually been milled and the new vertex 10 formed between them.

It cannot, however, be ruled out that the phase of verification can be carried out through an automated check.

Next, the method involves the phase of definition.

As stated above, the phase of definition comprises a step of drilling the blank bushing 12.

The phase of definition and, specifically, the step of drilling, is carried out by means of a drilling tool according to the predefined path.

In accordance with the preferred embodiment, prior to the step of drilling, the phase of definition comprises a step of application of the blank bushing 12 to the petal to be regenerated 1. In other words, the new hole 11 is made with the blank bushing 12 already applied to the petal to be regenerated 1. This ensures extremely precise and accurate drilling. It cannot, however, be ruled out that the new bushing 13 may be applied to the petal to be regenerated 1 only after drilling.

In detail, the new hole 11 is drilled according to the grinding value. In even more detail, the phase of drilling is performed along a drilling axis which is shifted with respect to an original drilling axis along the Cartesian axis X by a value equal to the grinding value.

In this way, the spacing between the new vertex 10 and the new axis of rotation R2 corresponds to the original reference value (dl, Figure 6).

Advantageously, the phase of grinding and the phase of definition are performed on board the same working machine.

In more detail, the phase of grinding and the phase of definition are performed while the petal to be regenerated 1 is mounted and retained in the relevant housing on the working machine. The definition of the new hole 11 is, therefore, performed without disassembling the petal to be regenerated 1 from the relevant housing.

In other words, the phase of positioning and the phase of retaining are performed once and the subsequent phases of grinding and definition are performed in succession without the petal to be regenerated 1 having to be set up and/or machined on other machines.

This peculiar feature, in addition to ensuring remarkable speed of execution, makes it possible to avoid drilling errors due to incorrect assembly of the petal to be regenerated 1 on an additional machine.

In fact, if the phase of definition were performed on a different machine from the one used for the phase of grinding, there would be a risk of not placing the petal to be regenerated 1 exactly in the predefined position and drilling in the wrong place.

It should be noted, in fact, that the phase of grinding involves the removal of a few hundredths of a millimeter and, at the same time, the position of the new hole 11 differs from the position of the original hole 2 by a few hundredths of a millimeter. It is evident, therefore, that it is necessary to perform the phases of the present method in a very precise and accurate manner.

Alternative embodiments of the present invention cannot however be ruled out wherein the phase of grinding and the phase of definition are performed on separate machines.

It has in practice been ascertained that the described invention achieves the intended objects, and in particular, the fact is emphasized that the method for regenerating diaphragm petals according to the invention makes it possible to avoid excessive replacement jobs of the petals of a diaphragm.

In addition, the present method for regenerating diaphragm petals ensures proper function of the relevant diaphragm.

Finally, the present method for regenerating diaphragm petals keeps production costs down.