Patent Description:
Rectangular tub vibrators are well known, i.e. machines for vibrofinishing long items, such as tubes, bars and, in the case of the aerospace and energy sector, turbine blades that are more or less long and/or more or less heavy.

As is well known, a vibrator for vibratory finishing generally comprises a rectangular tub designed to contain finishing media and a frame configured to accommodate at least one workpiece to be subjected to vibratory finishing.

In turn, the tub is mounted on a plurality of springs connected to a base and is mechanically associated with at least one vibrator motor or to a vibrator connected to a motor by means of an appropriate connection that sets it in vibration.

The vibration of the tub gives a vibratory motion to the finishing media that allows the finishing operation on the workpiece.

In the case of turbine blades, for example, these need to be loaded into the machine beforehand and fixed to a frame, one side being much heavier than the other.

The frame with the blade mounted on it is then lowered into the finishing tub with the help of a crane and fixed, for example with handwheels, to the tub itself.

A first problem of this known technique is that the presence of the finishing media makes it difficult to lower the frame in the tub using the crane when the blade is mounted thereon.

A second problem is the fact that pre-assembling and then disassembling the frame of each blade subjected to vibrofinishing is a laborious and time-consuming operation.

It should also be noted that, as the average vibratory finishing cycle is of about <NUM>-<NUM> minutes, an operator cannot manage three vibratory finishing machines at the same time, at the rate of one frame being assembled and disassembled every <NUM> minutes.

Document <CIT> discloses a system capable of immersing - in a vibrating polishing apparatus - a workpiece of annular shape and characterized by having flat surfaces, wherein the workpiece is supported by a rotating frame defined as a polishing jig. Such machine has a fixed support structure outside the vibrating polishing apparatus and also has means to bring the rotating frame from a position of loading/unloading the workpiece to a position suspended above the vibrating polishing apparatus. A jack lowers the workpiece W into the vibrating polishing apparatus and return it to its raised position at the end of machining. The workpiece is fastened by fastening means such as bolts to first and second guard members.

Document <CIT>discloses a plant equipped with traditional circular vibratory finishing machines which working bowls or vibrators have a ramp that enables, when needed, the deviation of the mass media and workpieces, over a final separating grid; this separating grid is enabling the workpieces to be separated whilst, the media, are passing through the separating grid and return back to the working bowl.

A rectangular "parking" area is shown, which has two empty spaces in the middle, suitable to receive the separating grid of both the represented vibrators, to allow the gripper to:.

Document <CIT> is therefore describing a plant that performs the automatic task to substitute separating devices or grids of vibratory finishing machines, working as "mass finishing equipments" with a big volume of parts in mass.

The purpose of this invention is therefore to solve the problems described by means of a vibratory finishing machine that allows to simplify and speed up the loading and unloading operations of long parts such as turbine blades.

A further aim of this invention is to achieve the above results in a practical and economical way.

The technical problems highlighted above are solved by a vibratory finishing machine, as defined in claim <NUM>, which includes a finishing unit, said finishing unit including a tub suitable to contain finishing media, said tub being mounted on a plurality of springs connected to a base and being mechanically associated with vibratory means, the machine further comprising a frame configured to accommodate a workpiece to be subjected to vibratory finishing.

According to the invention, the frame has means for automatic clamping of the workpiece in the working position.

In addition, the frame can be slid vertically along suitable guides from a first mounting or loading and unloading position of the workpiece to be finished to a second position where the workpiece can be immersed in the finishing media inside the tub and vice versa.

One advantage of the invention is that it enables the loading and unloading of workpieces to be handled quickly.

In particular, combining several machines according to an embodiment of the invention in a robotized island and served by an anthropomorphic robot a robotized system can be created that therefore has the ability to treat a blade every <NUM> minutes with obvious advantages of efficiency.

An embodiment of the invention comprises a vibratory finishing machine, wherein said machine comprises a finishing unit, said finishing unit comprising a tub suitable to contain finishing media, said tub being mounted on a plurality of springs connected to a base and being mechanically associated to vibratory means, the machine further comprising a frame configured to accommodate at least one piece to be subjected to vibratory finishing, characterized in that said frame is equipped with an element suitable to support, by means of clamping or interlocking, one side of the workpiece and with a mobile component driven by a jack or pneumatic cylinder to suitable act on the opposite side of the workpiece for automatic locking in the working position of the workpiece and by the fact that the said machine presents is equipped with a fixed support structure, wherein said fixed support structure is external to said finishing unit and is associated to a mobile structure configured to bring said frame from a first mounting position of the workpiece to be processed to a second position where the workpiece is immersed in the finishing media inside the tub and vice versa.

The invention also provides a method for carrying out vibrofinishing operations that includes a phase of assembly on the frame of the piece to be processed with the aid of an anthropomorphic robot, said assembly phase including a fastening phase by clamping one side of the workpiece and a fastening phase of the opposite side of the workpiece by the action of a mobile component operated by a jack or a pneumatic cylinder, a phase of immersion of the frame containing the piece in the tub by means of an action on a vertical axis of a mobile structure that carries the frame, a phase of vibratory finishing of the piece by means of the action of the vibrators on the tub and a phase of unloading of the piece by lifting the mobile structure carrying the frame and subsequent release of the jack or pneumatic cylinder and gripping of the piece by the anthropomorphic robot.

Further features of the invention can be inferred from the dependent claims.

Further features and advantages of the invention will be evident from reading the following description provided by way of non limitating example, with the help of the figures illustrated in the attached tables, in which:.

With initial reference to <FIG>, a side view of a vibratory finishing machine is shown according to an embodiment of the invention in a first operating position, said machine being globally indicated with numerical reference <NUM>.

Machine <NUM> includes a rectangular tub <NUM> suitable for containing finishing media, where said tub <NUM> is mounted on a plurality of springs <NUM> connected to a base <NUM>.

The tub <NUM> is mechanically associated to a vibrator motor <NUM> which vibrates the tub <NUM> in order to cause the abrasive and finishing action on the work piece of the media contained in the tub itself.

In general, the tub <NUM> is associated with vibratory means to be placed into vibration, the vibratory means including at least one vibrator motor or a vibrator, or a vibrating pack, wherein vibrating pack means a vibrator connected to others in line and finally to a motor.

In the figures, tub <NUM> is represented, by way of example, with a rectangular shape, but the shape of the tub can be chosen between rectangular, triangular, ellipsoidal, circular or other geometric shape depending on the application without limiting the scope of the present invention.

The tub <NUM>, mounted on springs <NUM>, the base <NUM> and the vibrator motor <NUM> form a finishing unit <NUM>.

The machine <NUM> further includes a frame <NUM> configured to accommodate at least one workpiece <NUM> for vibratory finishing.

The frame <NUM> has means for the automatic locking in working position of the workpiece <NUM> to be machined and can be slid vertically along suitable guides <NUM> from a first mounting position of the workpiece <NUM> to be machined to a second position where it is possible to immerse the workpiece <NUM> in the finishing media inside the rectangular tub <NUM> and vice versa.

Machine <NUM> has in fact a fixed support structure <NUM> configured to support the frame <NUM>, said structure <NUM> being external to the finishing unit <NUM> and is associated with a mobile structure <NUM>.

The means for the automatic clamping in working position of the workpiece <NUM> to be machined include an element <NUM> to support one side of the workpiece <NUM> to be machined and a mobile component <NUM> operated by a pneumatic cylinder <NUM> to act on the opposite side of the workpiece <NUM>.

Obviously, instead of the pneumatic cylinder <NUM> a jack or other known means for automatic clamping of the workpiece in the working position can be used.

In other words, the frame <NUM> is always present in machine <NUM> and is similar to a workbench vice.

The frame <NUM> is initially in a vertical position over the tub <NUM>.

The assembly of a workpiece <NUM> to be machined, e.g. a turbine blade, is therefore done in the following way.

A robot supports the blade on the left side (also called blade root) in the figures, the blade having a shape that allows its support by interlocking or clamping, for example, with a component <NUM> associated to the frame <NUM>, while the opposite side of the head (i.e. the tip) of the blade remains free and distant from the other side of the frame <NUM> when open (see also <FIG> and <FIG>).

By the action of a hydraulic jack <NUM>, the mobile component <NUM> is pushed to the left in <FIG> and then carried on the turbine blade head, said mobile component <NUM> presenting a plinth <NUM> made, for example, in elastic and resilient polyurethane to facilitate the locking of the blade on the frame <NUM> (see also <FIG> and <FIG>).

The fixed support structure <NUM> of the frame <NUM> and external to the finishing group <NUM>, has a plurality of vertical uprights <NUM> and the mobile structure <NUM> associated with the fixed support structure <NUM> can be operated vertically along said uprights <NUM> by means of the action of the respective cylinder-piston groups <NUM>.

This mobile structure <NUM> therefore allows to perform a phase of immersion of the frame <NUM> containing the workpiece <NUM> in the tub <NUM> along the vertical axis, followed by a phase of vibratory finishing of the workpiece <NUM>, said phase taking place by vibrating the tub <NUM> and the media contained in it, by activating the vibrator <NUM> (see also <FIG> and <FIG>).

Finally, a phase of unloading the piece <NUM> by lifting the mobile structure <NUM> that carries the frame <NUM> is performed.

It is therefore clear that the assembly of the workpiece, the immersion of the workpiece in the tub <NUM> and the unloading of the workpiece have been automated and speeded up thanks to the invention described.

According to an embodiment of the invention it is possible, for example, to realize a robotized system that includes three vibrofinishing machines <NUM> as shown above, placed in the same operating island and served by an anthropomorphic robot (not represented because known in the art), a robotized system that therefore has the ability to treat a blade every <NUM> minutes with obvious advantages of efficiency.

Claim 1:
A vibratory finishing machine (<NUM>), said machine (<NUM>) comprising a finishing unit (<NUM>), said finishing unit (<NUM>) comprising a tub (<NUM>) suitable for containing finishing media, said tub (<NUM>) being mounted on a plurality of springs (<NUM>) connected to a base (<NUM>) and being mechanically associated with vibratory means (<NUM>), the machine (<NUM>) further comprising a frame (<NUM>) configured to hold at least one workpiece (<NUM>) to be subjected to vibratory finishing, wherein said frame (<NUM>) is provided with an element (<NUM>) capable of supporting by clamping one side of the workpiece (<NUM>) to be machined and with a moving component (<NUM>) operated by a jack or a pneumatic cylinder (<NUM>) to act on the opposite side of the workpiece (<NUM>), for the automatic fastening in a working position of the workpiece (<NUM>) and in that said machine (<NUM>) is provided with a fixed support structure (<NUM>), said fixed support structure (<NUM>) being external to said finishing unit (<NUM>), wherein the fixed support structure (<NUM>) is associated with a mobile structure (<NUM>) configured to bring said frame (<NUM>) from a first position of assembly of the piece (<NUM>) to be processed to a second position in which the piece (<NUM>) is immersed in the finishing media inside the tub (<NUM>) and vice versa.