EP0447290A1 - Machine for deburring of metallic castings - Google Patents

Abstract

The machine for deburring, which can be used for metallic castings cast under pressure, comprises a press having means for receiving a rough casting (10) and a tool (38) which is movable vertically towards the said means for separating the rough foundry casting into waste and useful casting (12). These means comprise a countertool (26) having, from a rupture edge of the rough foundry casting, a downward slope. This means are connected to a stationary structural frame by support means (24,22) having downward-inclined surfaces and delimiting wide openings which make it possible for the debris to fall via these openings. <IMAGE>

Description

The present invention relates to a machine for deburring metal parts obtained by molding.

It finds a particularly important application in the workshops for manufacturing metal parts under pressure and in particular in light alloy. By way of example, mention may be made of castings made of aluminum or a foundry alloy such as "zamac" which, after machining, constitute the body of an internal combustion engine supply device, in particular the a carburetor or the throttle body of an injection system.

The blank which comes out of a pressure molding press consists of the useful part and metal blocks solidified during casting in the mold and connected to the useful part by thin parts. When the useful part is of complex shape, correct filling of the mold can only be obtained at the cost of producing a raw part comprising waste the weight of which can exceed 60% of that of the raw product, divided into fragments of very variable mass (casting jet, heavy weight; flyweight; washing heel; burr; etc).

Part deburring machines are already known, used in automated workshops, of the type comprising a press having means for receiving the raw part and a tool, movable vertically towards the receiving means, intended to separate the waste from the part. useful.

On this press, the blank is placed on a horizontal plate. Its weight keeps it in place during deburring, which avoids the use of clamping means of the workpiece in position. However, the disposal of casting waste on these machines poses a problem which is only very imperfectly resolved. In general, the jet of casting, which is the most bulky waste, is seized and transferred to a waste bin by the robot which is used to bring the blank. Small waste, such as weights, is normally evacuated by gravity into chutes, but experience has shown that there is a lot of waterlogging. Light debris falls on the press bed or on the floor. Their dispersion hinders manufacturing and is the cause of incidents.

It has also been proposed to use a deburring press with a vertical plate for receiving the blank and a tool with horizontal displacement. Thus the waste falls under the press and can be collected directly in a container. This solution complicates the implementation. In particular, it prohibits automatic gravity centering on guide cones and therefore requires the workpiece to be held during deburring.

The present invention aims in particular to provide a deburring machine of the type defined above better meeting those previously known to the requirements of practice, in particular in that it facilitates the collection and recovery of waste.

To this end, the invention provides a machine characterized in that said receiving means comprise a counter-tool having, from a breaking edge of the raw part between the useful part and the waste, a significant downward slope. and in that the counter-tool is connected to a fixed frame by means also having surfaces inclined downward and delimiting large openings allowing the debris to fall into a container.

The absence of a horizontal or gently sloping surface prevents the retention of waste around the counter-tool. The rupture between useful part and waste is advantageously caused by driving in the useful part by a tool vertically displaceable by a hydraulic cylinder and intended to bear on the edges of the useful part and pushing in the useful part by pushing back a useful part support plate; this plate can be supported by a fluid pressure counter-cylinder, making it possible to exert a lifting force of the plate lower than the force of the first cylinder.

• la figure 1 est une vue schématique d'une machine, en élévation et en coupe partielle suivant un plan vertical passant par l'axe de l'outil,
• la figure 2 est une vue schématique de dessus de la figure 1,
• les figures 3A et 3B montrent des coupes représentatives de formes que peuvent prendre les bras supportant l'outil, en coupe suivant la ligne III-III de la figure 2,
• la figure 4 est une vue en élévation et en coupe partielle à grande échelle, montrant une forme possible d'outil et de contre-outil,
• la figure 5 est une vue de dessus montrant le contre-outil de la figure 4 et une pièce brute à ébarber,
• les figures 6 et 7, similaires aux figures 1 et 2, montrent une constitution possible de machines comportant également des vérins horizontaux,
• la figure 8 est une vue de gauche de la figure 6.

The invention will be better understood on reading the following description of a particular embodiment of the invention, given by way of non-limiting example. The description refers to the accompanying drawings, in which:

• FIG. 1 is a schematic view of a machine, in elevation and in partial section along a vertical plane passing through the axis of the tool,
• FIG. 2 is a schematic top view of FIG. 1,
• FIGS. 3A and 3B show sections representative of the shapes which the arms supporting the tool can take, in section along line III-III of FIG. 2,
• FIG. 4 is a view in elevation and in partial section on a large scale, showing a possible form of tool and counter-tool,
• FIG. 5 is a top view showing the counter-tool of FIG. 4 and a rough part to be trimmed,
• FIGS. 6 and 7, similar to FIGS. 1 and 2, show a possible construction of machines also comprising horizontal jacks,
• FIG. 8 is a view on the left of FIG. 6.

The machine shown diagrammatically in FIGS. 1 and 2 is intended for deburring rough casting parts 10 comprising a useful part 12 to which waste remains attached, such as for example a casting jet 14, weights 16 and burrs (not represented). It will be assumed in the following that the useful part to be detached is delimited by a circular line, but any other form would be acceptable, especially since the line is in one plane.

The machine comprises a fixed and robust frame, having a frame 18 carried by feet 20 and connected by radial arms 22 to a central crown table 24 for receiving a counter-tool 26. The counter-tool has a directed edge upwards and whose path reproduces that of the rupture line of part 10. This path is planar but could have offsets. On a cylindrical internal face of the counter-tool slides with gentle friction, a stripping plate 28 for reception, the plan shape of which is that of the useful part 12. The external face of the counter-tool has a high downward slope, advantageously greater than 45 °, so that the detached debris slide along the counter-tool 26 and pass through the large openings delimited by the crown 24 and the arms 22, which constitute means for supporting the counter-tool 26. The outer face of the crown 24 also has a high downward slope and is connected to that of the counter-tool 26. The arms consist of solid or tubular bars which either have a straight section with a steep slope, having no horizontal upper part notable (case of FIG. 3A), or else are covered with a steep roof deflector 30 (FIG. 3B).

In the embodiment shown in Figures 1 and 2, the plate 28, provided with means 32 for centering the useful part 12, is carried by the piston of a counter-cylinder 34 whose cylinder is connected, by webs 36 , to the crown 24. The diameter of the cylinder of the counter-cylinder 34 is much smaller than that of the crown 24, so as to avoid the catching of debris on the cylinder. The upward movement of the plate 28 can be limited by the support of the piston of the counter-cylinder 34 against the cylinder or by external means. In its highest position, the plate maintains the part 10 above the edge of the counter-tool 26.

The rupture of the blank 10 is caused by the descent of a tool 38 which can be secured to the piston of a jack 40. The fixed cylinder of the jack 40 can in particular be carried by a bracket 42 secured to the frame 18. The tool 38 has a bearing surface on the blank, the external contour of which corresponds to that of the edge of the counter-tool 26. The jack 40 is designed to exert sufficient force to overcome the opposing force exerted by the jack 34 and the resistance shear of the blank 10.

A container 44 can be brought between the feet 20 of the machine, in order to collect all the detached waste, and removed.

Figures 4 and 5 (where the elements already shown in Figures 1 and 2 have the same reference number) show an example of tool 38 and counter-tool 26, usable for deburring a useful part 12 constituted by a body of throttle valve for internal combustion engine injection device. In Figures 4 and 5, the waste to be separated is indicated in dashed lines. The body constituting the useful part is in the form of a disc delimited by a circular edge, having a central injector holder connected by two wings to lateral bosses projecting upwards and downwards, all these elements being pierced with holes. fuel and air passage.

The counter-tool 26 is in the form of an annular block with a prismatic outer face, with two slopes and with a cylindrical internal bore, limited upwards by the breaking edge. In the bore slides the plate 28, removably attached to the piston 46 of the lower cylinder. The tool 38 has a coping intended to be applied against the disk of the useful part 12 and a recess of sufficient size to accommodate the injector holder and the bosses. This tool is removably attached to the piston 48 of the upper cylinder 40.

The plate 28 has recesses making it possible to house the bosses. The lifting of the plate 28 under the action of the counter-cylinder is limited by abutment of a plate 50, integral with the plate 28, against the crown which carries the counter-tool. This abutment occurs at a level such that the blank is immediately above the edge of the counter-tool 26.

When the blank foundry to be trimmed has holes, the latter often remain closed by thin scales coming from molten metal which has slipped between the drawers intended to reserve the openings and the holes. These holes often open transversely to the waste separation plane, defined by the breaking edge.

To carry out, in a single operation, the deburring of the part by rupture along the connection line of large waste and the clearance of the holes, one can use a machine of the kind shown in Figures 6 to 8 (where the bodies corresponding to those of FIGS. 1 to 5 still bear the same reference number).

The machine of FIGS. 6 to 8 comprises a transverse jack 52, the piston of which can receive a tool 54 for unblocking the holes oriented parallel to a first direction x and which can also be used to hold the blank foundry piece pressed against an anvil 56 during the unblocking of the holes oriented in an orthogonal direction y, using a second tool controlled by a jack 58. It is possible to provide an additional jack 60 for clamping and / or unclogging.

In the case considered above of deburring of foundry parts intended to constitute throttle bodies, the jack 40 can have a stroke of several tens of millimeters, to free the space necessary for the establishment and removal of the parts, and exerting a force of approximately 10 tonnes. The counter-cylinder 34 can have a very short stroke, of a few centimeters, and can yield under a force of the order of a ton. The cylinders 52 and 58 can be provided with a stroke of tens of centimeters and to exert a force of the same order of magnitude as the counter-cylinder 34.

The weight of the waste such as scales and burrs may be insufficient to slide it along the walls towards the container 44.

To remove these burrs and barbs, the counter tool can be provided with compressed air passages connecting blowing nozzles to nozzles 62 fitted to the crown table. The nozzles are then connected to an air supply unit, comprising a valve which opens for a determined period of time each movement of the jack 40 causing the lifting of the tool 38.

The operation of the machine follows directly from the above description. A robot brings each blank part in turn and places it on the plate 28, provided with centering and possibly orientation means, while the tool 38 is lifted.

The jack 40 is then pressurized to cause the tool to descend. This tool 38 comes to rest on the disc of the foundry part 10, drives the useful part 12 by fracturing the junction zones with the waste and pushes back the piston of the counter-cylinder 34. Optionally, the transverse tightening cylinder, as well that the transverse unblocking jacks are set in motion after the piston of the jack 40 descends and the blank is cut. The waste falls into container 44.

The double-acting cylinder 40 is then actuated in the direction of ascent and raises the tool 38. Under the action of the pressure prevailing in the counter-cylinder 34 (which can be single-acting) the useful part returns to its original position. At the same time, the blowing nozzles direct air jets onto the plate and the part, which expel any barbs that may have been deposited.

Finally, when the tool has returned to the high position, the useful part can be removed with the same robot which is then used to bring in a new raw part.

The same press can be provided to receive various types of tool, counter-tool and plate, chosen according to the shape of the useful parts to be produced. The press can be automatic as well as manual.

Claims (6)

Machine for deburring molded metal parts, comprising a press having means for receiving the raw part (10) and a tool (38), movable vertically towards the said means, for separating the raw part from the foundry into waste and useful part ( 12), characterized in that said means comprise a counter-tool (26) having, from a breaking edge of the blank foundry, a high downward slope and in that said means are connected to a fixed frame by support means (24,22) having surfaces inclined downward and delimiting large openings allowing debris to fall through these openings. Machine according to claim 1, characterized in that said tool (38) is designed to rest on the useful part and sink into the counter-tool (26). Machine according to claim 2, characterized in that the workpiece receiving means also comprise a plate (28), sliding vertically in the counter-tool (26), carried by a fluid pressure cylinder (34). Machine according to claim 3, characterized in that the plate (28) is provided with means for centering the useful part and means limiting its vertical upward movement to a position for which the line of separation between useful part and waste is immediately above the edge of the tool holder. Machine according to any one of the preceding claims, characterized in that the said support means comprise a crown (24) for receiving the counter-tool (26) and arms (22) for connection with a frame (18) of the frame, with faces inclined downwards. Machine according to claim 5, characterized in that the arms consist of solid bars or tubulars elongated in the vertical direction or by bars covered with a deflector (30) whose faces have a high downward slope.

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