WO2000054910A1

WO2000054910A1 - Device for decoring casting pieces

Info

Publication number: WO2000054910A1
Application number: PCT/EP2000/002266
Authority: WO
Inventors: Giorgio Cestaro
Original assignee: Cestaro Fonderie S.R.L.
Priority date: 1999-03-17
Filing date: 2000-03-15
Publication date: 2000-09-21
Also published as: ITVI990053A1; IT1308141B1; ATE230319T1; ES2188525T3; DE60001110D1; DE60001110T2; CZ20013293A3; EP1169153A1; EP1169153B1; AU3811200A

Abstract

A decoring device for foundry castings, particularly useful in the casting industry for aluminum alloys and the like for removing the core from castings, includes a metal supporting frame, a vibrator (10) for vibrating a casting (G) which is supported by the frame, and a clamp (24) for clamping the casting so that it faces the vibrator. The clamp is rigidly coupled to the vibrator and both can rotate with respect to the frame. The invention fully solves the problems observed in conventional devices, since it achieves a considerable economic advantage due to the reduced need for workers to handle the parts and to the considerable speed with which the process is performed.

Description

DEVICE FOR DECORING CASTING PIECES

The present invention relates to a sand flogging device for foundry castings which is particularly but not exclusively useful in the casting industry for aluminium alloys and the like. It is known that a very large number of hollow metallic parts, for example for the automotive and domestic sectors, et cetera, are obtained by casting the molten metal into shells of compacted sand, which in turn accommodate one or more cores made of the same material in order to form, for example, internal walls, diaphragms and the like. Before being subjected to subsequent finishing processes, the resulting semifinished item, also known as casting, is then freed from the shell and the corresponding core. Breaking the shell is in itself an extremely simple operation, since it is sufficient to shake the casting, while in order to free the casting from the core it is necessary to act violently, for example with a pneumatic hammer, on the core until it breaks up, and then make the sand thereof exit from the casting through the openings of the casting. It is evident that this typically manual method is unfeasible in medium, large and very large mass- productions. In order to overcome this problem, sand flogging, or knock-out, devices have been provided which consist substantially of a platform which supports a percussion member and a fixed abutment which face each other and between which the operator places the casting, after it has been freed of the shell, in order to subject it to strong vibration so as to break up the internal core.

A first drawback of these devices is the rather long time required to perform the process, due both to the difficulties that operators encounter in handling the parts and to the efficiency and effectiveness of the apparatus itself, accordingly entailing significantly high labor and running costs. A second drawback is due to the higher-than-normal noise and vibrations to which operators of this device are exposed.

The aim of the present invention is to overcome the above cited drawbacks of the prior art sand flogging devices. An object of the invention is to provide a sand flogging device for foundry castings which allows to minimize manual intervention.

A further object of the invention is to minimize the process times, achieving a considerable economic advantage with respect to the prior art devices.

A further object of the invention is to provide a sand flogging device with constructive solutions which drastically reduce the transmission of vibrations to the floor and accordingly to the operators and the overall noise of the process.

Still a further object of the invention is to provide a sand flogging device which complies with the limits and constraints of applicable statutory provisions covering workplace hygiene and safety. This aim, these objects and others which will become apparent hereinafter are achieved by a sand flogging device for foundry castings, as claimed in the appended claims.

Further characteristics and advantages of the invention will become apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

Figure 1 is a front view of the sand flogging device according to the invention;

Figure 2 is a side view of the sand flogging device of Figure 1 ; Figure 3 is a side view of the front portion of the sand flogging device of

Figure 2 in a first working position;

Figure 4 is a side view of the portion of Figure 3 in a second working position.

With reference to the accompanying figures, the sand flogging device for foundry castings, generally designated by the reference numeral 1 , comprises a metal frame 2 which is composed of a pair of facing vertical portals 3 and 4 and by lateral longitudinal members 5 for joining the portals 3 and 4. Three wings 6 protrude within the area formed by the front portal 3. One of the wings protrudes from the upper cross-member and two of the wings protrude from the lower cross- member, and each wing rotatably supports a guiding member 7. Likewise, three wings 8 protrude within the area formed by the rear portal 4. Two of the wings protrude from the upper cross-member and one of the wings protrudes from the lower cross-member, and each wing rotatably supports a guiding member 9. The wings 6 and 8, by virtue of the guiding members 7 and 9, rotatably support vibrating means 10 for vibrating the casting (G). The vibrating means 10 comprises a first tubular body, generally designated by the reference numeral 11 , whose longitudinal axis is parallel to the floor. The tubular body elastically accommodates a second coaxial tubular body, generally designated by the reference numeral 12, which in turn supports a pneumatic vibrating head, generally designated by the reference numeral 13, at its front end. An actuation source, such as a gearmotor 14 arranged on the frame 2 in an upward region, and a transmission member, associated with the first tubular body, in the specific case an annular ring 15 which surrounds it circumferentially, which are mutually connected by means of a motion transmission member, for example a chain 16, turn on command the vibrating means 10 about the longitudinal axis of the first tubular body 11. When necessary, it is possible to vary the tension of the chain 16 by means of a tensioner 17 which acts on the inclined portions of the chain. The first tubular body 11 is composed of two first facing annular members 18a and 18b which are joined by welding to four first bars 19 which have the same length, are arranged around their perimeter and are evenly spaced. Conveniently, the outer edge of the first annular members 18a and 18b which faces the guiding members 7 and 9 is shaped so as to form rolling tracks for the members. In particular, the outer edge of the first front annular member 18a is raised so as to engage complementarily shaped circumferential grooves formed in the guiding members 7. The second tubular body 12 is formed by a second rear annular member 20 and by a front circular plate 21 which face each other and are joined by welding, as in the first tubular body 11 , to four second bars 22 which are in turn rigidly coupled to the first bars 19 by interposing, at their ends, elastic inserts 23, for example small rubber cylinders. The front plate 21 is centrally provided with a through hole for accommodating the vibrating head 13 and rigidly supports the casting clamping means, generally designated by the reference numeral 24. In detail, with particular reference to Figures 3 and 4, the vibrating head 13 comprises a tubular member 25 which is fixed to the plate 21 inside its central hole, a percussion means 26, which is accommodated within the tubular member 25, and can mutually slide axially by pneumatic actuation between a retracted position (Figure 3) with respect to the casting (G) and a forward position (Figure 4) in contact with the surface thereof, and a front lid 27 for closing the tubular member 25 with a central hole for the passage of the percussion means 26. The clamping means 24 is constituted by a first fixed jaw 28, which is rigidly connected by bolting to the plate 21 , and by a second jaw 29, which can move between a spaced position (Figure 3) with respect to the first jaw 28, for loading and unloading the casting (G), and a closer position (Figure 4) for locking the casting. In detail, the first jaw 28 has a central through hole, which corresponds to the hole of the lid 27 and from which the front portion of the percussion means 26 protrudes when the percussion means is in the forward position, and supports, at its ends, two cylindrical guides 30 which are engaged in corresponding holes, formed at the ends, of the second jaw 29 which in turn is provided with a central hole which is aligned with the hole of the first jaw 28, for accommodating a member 31 for reacting to the action applied by the vibrating head 13. The reacting member is constituted by a mushroom-shaped pin 32, whose stem is partially inserted in the hole and whose head is in contact with the surface of the locked casting (G), and by a pack of springs 33, for example of the Belleville type, which are interposed between the head and the second jaw 29.

The sand flogging device 1 comprises a soundproofing enclosure, generally designated by the reference numeral 34, which can be opened by moving, in guillotine fashion, a front panel 35 and an upper panel 36 for loading and unloading the parts. The sand flogging device also includes a control console (not shown) of the keypad type for actuating, stopping and controlling respectively the rotation of the vibrating means 10, the vibrating head 13, the front panel 35 and the upper panel 36. The operation of the sand flogging device is described hereinafter with reference to the accompanying figures. Conveniently, in order to facilitate the loading operation, the sand flogging device 1 is provided with a bracket-like structure (not shown) which is preset for a series of castings (G) and is rigidly connected to one of the jaws 28 and 29. When the front panel 35 and the upper panel 36 are in the open position, the operator loads a casting (G) onto the bracket system and then, after closing the front panel 35 and the upper panel 36, locks it between the vibrating head 13 and the reacting member 31 , actuating the clamping means 24 by means of the keypad. Again by means of the keypad, the operator activates the vibrating head 13 and turns, according to requirements, in one direction or the other the vibrating means 10. After a few seconds, the core (A), subjected to the vibrating action, begins to break up and the grains of sand begin to flow out continuously from the openings of the casting (G). Once the core (A) has been broken up completely, the operator stops the vibrating head 13 and the rotation of the vibrating means 10, so that the casting (G) arranges itself in the initial position; then he releases the clamping means 24, opens the front panel 35 and the upper panel 36 and manually unloads the casting (G). The operation is repeated likewise for the other castings of the series.

In practice it has been observed that the described sand flogging device achieves the intended aim and objects, since it achieves a true reduction in operating costs due to the significant reduction in the time for which workers handle the castings and due to the speed of execution of the process. Furthermore, by providing, inside the factory, processing stations which are composed of a plurality of sand flogging devices, it is possible to optimize the casting processing cycle. Careful choice of the components and their assembly allow the sand flogging device to easily exceed the statutory standards covering workplace health and hygiene, significantly helping to improve the working conditions of the personnel.

The sand flogging device according to the invention is susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept expressed herein.

All the details may be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements.

Claims

1. A sand flogging device for foundry castings, characterized in that it comprises a supporting frame, a vibrating means for vibrating at least one casting, said vibrating means being supported by said frame, and a means for clamping said casting so that it faces said vibrating means, said clamping means rotating with respect to said frame.

2. The device according to claim 1 , characterized in that said frame comprises two facing portals, lateral longitudinal members for joining said portals, and wings which protrude inside said frame and rotatably support guiding members.

3. The device according to one or more of the preceding claims, characterized in that said vibrating means comprises a first tubular body which is rotatably supported by said guiding members, a second tubular body which is accommodated coaxially and elastically in said first body and at least one vibrating head which is rigidly coupled to said second body at one of its ends.

4. The device according to one or more of the preceding claims, characterized in that it comprises an actuation source, a motion transmission member which is associated with said vibrating means, and a motion transfer member which connects said source to said transmission member, and in that it comprises a tensioner for said transfer member.

5. The device according to one or more of the preceding claims, characterized in that said first tubular body comprises two first facing annular members, a plurality of first bars for joining said first members which are arranged around the perimeter of said first members, the outer edge of said first members being shaped so as to form a rolling track for said guiding members.

6. The device according to one or more of the preceding claims, characterized in that at least one rolling track is shaped so as to engage complementarily shaped circumferential grooves formed in said guiding members associated with one of said portals.

7. The device according to one or more of the preceding claims, characterized in that said second tubular body comprises a second annular member and a circular plate for accommodating said vibrating head which face each other, and a plurality of second bars for joining said second annular member and said plate which are arranged around the perimeter of said second member and said plate, said second bars being connected to said first bars by interposing elastic inserts.

8. The device according to one or more of the preceding claims, characterized in that said vibrating head comprises a tubular member which is fixed to said plate with one end, a percussion means which is accommodated within said tubular member and can mutually move between a retracted position, which is spaced from said casting, and a forward one, in contact with the surface of said casting, and a closure cover, at the other end of said tubular member, with a central hole for the passage of said percussion means.

9. The device according to one or more of the preceding claims, characterized in that said clamping means comprises a first jaw which is rigidly coupled to said plate with a central hole for the passage of said percussion means, a second jaw with a central hole for accommodating a member for reacting to said vibrating head, said second jaw being movable between a position which is spaced from said first jaw, for loading and unloading said casting, and a contact position for locking said casting.

10. The device according to one or more of the preceding claims, characterized in that said reacting member comprises a mushroom-shaped pin whose stem is partially inserted in said hole and a pack of springs which is interposed between the head of said pin and the surface of the movable jaw.

1 1 . The device according to one or more of the preceding claims, characterized in that it comprises a soundproofed containment enclosure, with a front panel and an upper panel which can be opened for loading and unloading said castings, and in that it comprises a keypad-type control console for controlling the rotation of said vibrating means, said vibrating head and said front and upper panels.