FR2511904A1 - Core sand removal from castings - in large vol. prodn. by electrohydraulic means - Google Patents

Abstract

Sand, partic. cores, is removed from castings in large vol. prodn. by electro-hydraulic means. Castings, suspended from trolleys running on a conveyor rail, are pushed along by dogs on a moving chain. Above a cleaning tank a detached section of rail is connected to a movable frame, hanging from a supporting structure. When a casting is in position the assembly is disengaged from the chain, and lowered into the tank. Cams contacting the rim of the tank close pivoting clamp arms onto the casting and bring forward electrodes connected to a pulse generator. After cleaning, frame etc. are lifted out, the rail section reengages, and the clamp is released. By this invention, in large vol. prodn. castings do not have to be unhooked from the conveyor, and closing the clamps onto the casting also positions the electrodes. Multi-track installations are also possible.

Description

 The present invention relates to the foundry industry and particularly relates to an installation for the electro-hydraulic cleaning of castings in order to rid them of foundry sand residues, especially for the breaking of foundry cores. It can be used in foundries of manufacturing companies in large and very large series.

 For the grit removal and casting operations of the foundry cores, pneumatic vibratory installations and installations using the energy of a high voltage electric discharge in a liquid (electrohydraulic effect) are widely used. Compared with conventional vibratory pneumatic systems, the latter type of installation has a number of advantages, including the suppression of dust forming in the dry sanding process, the suppression of vibrations and the intense noise exerting a harmful influence on the service personnel, possibility of breaking up foundry cores of any mechanical strength, as well as the possibility of automation and mechanization of the grit removal process.

 The main requirements for electro-hydraulic installations for the cleaning of castings during their production in very large batches are to ensure an efficient and high-quality casting of castings with minimum manual labor expenditure. they can be integrated into existing manufacturing lines and ensure high operational safety and convenient maintenance.

 An installation is known for the electro-hydraulic cleaning of castings (see, for example, USSR Certificate of Invention No. 406413, Cl.B22d 29/00), comprising a bath filled with liquid cleaning and a device for feeding the casting parts into the bath, realized in the form of two platforms with carriages moved by a cable and pulley control on inclined guides for alternately bringing the platforms at a loading position (in the high position) and at two treatment positions in the liquid bath (in the low position). In addition, the plant is provided with an autonomous mechanism for moving electrodes that are electrically connected to current pulse generators.

 In this embodiment of the installation, the casting parts to be desaminated must be unhooked from the transport conveyor suspension devices and stored on a loading table, the cleaned parts then being removed from the unloading table and hooked again. to the suspension devices of the conveyor. Therefore, in order to be able to integrate the Installation into a production line, additional devices are required to remove the conveyor parts and transfer them to the loading table, then remove them from the unloading table and hang them up to the conveyor suspension devices. The removal-hooking operations normally require manual labor expenditure. In addition, the fact of providing an autonomous mechanism for moving the electrodes leads to complicating the construction of the installation and the maintenance of the electrodes, the mechanism ensuring the maneuvering. electrodes only in the horizontal plane, without removing them from the cleaning liquid. But the visit and the repair of the electrodes requires their disconnection and their extraction of the cleaning liquid.

 Another electro-hydraulic cleaning device for casting parts is known (see, for example, the USSR inventor's certificate N0 396174> Cl.B22d 29/00), comprising a bath of cleaning liquid. in which is disposed at least one electrode connected to a current pulse generator, and which is mounted under the rail of an air conveyor with pushers for transporting the castings, and a device for feeding parts to the bath , realized in the form of a movable frame connected to the frame and provided with a member for fixing the parts made in the form of a control lever. In this installation, the frame is connected to the frame by means of a hinge which allows it to rotate about its horizontal axis. In addition, the frame is provided with stops with which the castings come into contact when they are unhooked from the conveyor and fixed by the control lever mounted on the frame.

 This installation only ensures the cleaning of the foundry parts after unhooking of the conveyor by the control lever and their supply to the liquid bath by the rotating frame. The control lever complicates the construction of the rotating frame, without allowing to unhook the parts of a conveyor with multiple suspensionSni, nor, therefore, to clean several parts at a time, which is the necessary condition typical for heavy traffic conveyors from automotive foundries and tractors. It also follows a limited production capacity of the installation.

 In addition, the operation of the electrodes in the installation is provided by an autonomous mechanism which complicates the construction and maintenance because of the impossibility of an operational visual inspection of the state of the electrodes which constitute an essential element intended to operate directly in the area of high voltage electrical discharge and to undergo dynamic electrical and mechanical loads.

 The electrodes are approached to the part to be cleaned of the part when it is immersed in the liquid, which completely excludes the visual control of the orientation of the electrodes relative to the part to be cleaned.

 In the context of the invention, it has therefore been proposed to create an installation for the electro-hydraulic cleaning of castings, the device for feeding the parts to the bath of cleaning liquid would be made so as to be able to clean the parts without unhooking them from the conveyor, thus making it possible to increase the productivity of the installation: and to simplify its construction.

 This object is achieved by the fact that the electrohydraulic cleaning system for casting parts, of the type comprising a cleaning liquid bath tank in which electrodes connected to at least one current pulse generator are arranged, and which is mounted under the conveyor rail of an air conveyor with pushers for transporting the castings on suspension members, and a device for feeding parts to the bath, in the form of a movable frame connected to a frame and having a fastener of said parts, is characterized, according to the invention, in that said frame is rigidly connected tou section of the rail-transporter of the air conveyor pushers which is arranged directly above said bath, and the device for feeding the parts to the bath comprises a mechanism for moving the frame vertically with the attachment member of the conveyor and the part to be cleaned, this mechanism making it possible to attach to the Conveyor the section of the carrier rail connected to the frame when it is in the upper position, the fastener of the parts attached to the suspension members being formed in the form of a clamp.

 It is advantageous that the electrodes are fixed on the clamp.

 It is also advantageous that the clamp is made in the form of two levers with two arms, that one of the arms of each lever is provided with a cam coming into contact with the frame in the upper position of the frame and with the flange of the tank in the lower position of the frame, and that the other arms of said levers are provided with bosses used to fix the part to be cleaned in the lower position of the frame under the action of the weight of the frame and the room.

 Such an embodiment of the installation for the electro-hydraulic cleaning of castings makes it possible to completely eliminate the operation and the hook-and-hold device of the parts, Greek to the fact that a section of rail-conveyor of the conveyor is fixed on the movable frame of the device for feeding the parts to the bath, so that the suspension member carrying the part to be cleaned is immersed with the lower part of the frame in the cleaning liquid bath. The section of the conveyor rail with the load carrier of the conveyor is then in the upper part of the frame and remains outside the bath, when the frame is in the low position. This greatly simplifies the construction of the installation.

 Fixing the electrodes on the clamp also helps to simplify the construction of the installation, because there is no longer a need for a mechanism for operating the electrodes.

 The fact of making the retaining clip of the parts to be cleaned in the form of two levers with two arms having cams and bosses makes it possible to fix the part without any additional control member, solely under the action of the own weight of the frame and of the piece and thanks to the main movement of the frame upwards, during which the clamp releases the part, which also contributes to simplify the construction of the installation.

 This embodiment of the electro-hydraulic installation, making it possible to carry out the cleaning of the casting parts without unhooking them from the suspension members of the conveyor, and the simplicity of the construction of the retaining clip of the parts to be cleaned, allow the cleaning of identical parts with a conveyor with 2, 4 and 6 suspensions and thus makes it possible to increase by as many times the production capacity of the installation, to widen its field of application and to use it in foundries manufacturing in very large series: on transport conveyors with multiple suspension components foundries in the automotive industry and tractors.

The invention will be better understood and other objects, details and advantages thereof will appear better in the light of the explanatory description which follows of various embodiments given solely by way of non-limiting examples, with references to the drawings. non-restrictive rules in which
- Figure 1 shows an overview of the Installation for the electro-hydraulic cleaning of castings (section along the axis of the conveyor for transporting castings), according to the invention;
- Figure 2 shows the same installation, but in section in a plane perpendicular to the axis of the conveyor.

 The installation for the electrohydraulic cleaning of castings comprises a tank 1 (FIG. 1, 2) with a bath of cleaning liquid (generally of industrial water) in which electrodes 2 connected by supply conductors are arranged. at current 3 (FIG. 2) to at least one current pulse generator (at the generator 4 in the example under consideration).

The tank 1 is mounted under a conveyor rail 5 (FIG. 1) of a push-type aerial conveyor 6 used to transport the castings 7.

 The installation also comprises a device for feeding the parts 7 into the tank 1, made in the form of a mobile frame 9 (FIGS. 1, 2) connected to a frame 8 and provided with a device for fastening the pieces 7. The movable frame 9 is rigidly connected to the section 10 (FIG. 1) of the conveyor rail 5 of the conveyor 6, which is arranged directly above the tank 1.

 The device for feeding the parts 7 to the bath 1 comprises a mechanism for vertically moving the frame 9 with a suspension member 11 of the conveyor 6 and the part to be cleaned 7, this mechanism making it possible to join to the conveyor 6 the section 10 of the rail- carrier 5 which is linked to the frame, when the frame is in the high position. In the example of embodiment of the installation, the vertical movement mechanism of the frame 9 is in the form of a winch 12 (FIG. 2), guide pulleys 13 and steel cables 14.

 The displacement of the parts to be cleaned 7 (FIG. 1) is ensured by load-carrying carriages 15 carrying the suspension members 11 and driven by a control chain 16 provided with carriages 17.

 The disjunction of the load carriage 15 from the control chain 16 occurs on the section 10 of the conveyor rail 5 by means of a controlled stop 18 (FIG. 2).

 As indicated above, the junction of the section 10 (FIG. 1) of the conveyor rail 5 to the conveyor 6 enables the load carriage 15 to freely leave the conveyor 6, to engage in the feed device of the parts 7 to the cleaning tank 1 and, once the cleaning is complete, to engage again on the conveyor 6.

 Such an embodiment of the device for supplying parts to the cleaning bath makes it possible to increase the production capacity of the installation by eliminating the stalling operations of the parts carried.

by the conveyor and their hang-up on the suspension members, and to simplify, therefore, the construction of the installation.

 In the lower position of the movable frame 9, when the conveyor rail 5 is cut, sensors (not shown in the drawings) provided on the conveyor 6 in order to avoid technical incidents prevent the following load carrier 15 enter the installation before the cleaning of the parts carried by the preceding carriage is completed.

 As the parts 7 are suspended from the suspension members 11 and are immersed with them in the bath 1, the parts fixing member 7 is in the form of a clamp 19.

 When the device for feeding the parts 7 to the tank 1 is made in the manner described above, it is advantageous to make the clamp 19 in the form of two two-arm levers 20 (FIG. 2), one of the arms of FIG. each lever 20 carrying a cam 21 coming into contact with the frame 8 in the upper position of the frame 9, and with a flange 22 of the vessel 1, in the lower position of the frame. The other arms of the levers 20 comprise bosses 23 for fixing the parts 7 in the lower position of the frame 9 under the action of the own weight of the frame 9 and the part 7.

 To simplify the construction of the installation, it is advantageous to fix the electrodes 2 on the clamp 19 (Figure 1) constituted by the levers 20 (Figure 2).

 The installation may be provided with electrodes of any known type, but it is more advantageous to use electrodes with a flexible current conductor throughout its length. This makes it possible to reduce the size of the installation and to arrange the electrodes in a horizontal position, which makes it possible to apply the discharge energy to the part to be cleaned in the most efficient manner (at its lateral surface, for example ), depending on the configuration of the room. In addition, the fact of providing electrodes flexible supply conductors that reduce their size, allows to orient them properly relative to any portion of the surface of the part to be cleaned, so to obtain the best conditions of cleaning.

 The operation of the installation for the electro-hydraulic cleaning of castings is as follows. The load carriage 15 (FIG. 1) carrying the parts to be cleaned 7 hooked to the suspension member 11 is driven by the control chain 16 and with the aid of the carriages 17 on the air conveyor with pushers 6 towards the device. supply of the parts 7 to the tank 1. When the carriage 15 engages the rail section 10 connected to the frame 9, the carriage 15 is detached from the control chain 16 by the controlled stop 18 (Figure 2). In the high position of the frame 9, the levers 20 rest by their cams 21 on the bed 8, which causes the spacing of the lower arms of the levers 20. The winch 12 lowers the frame 9 with the carriage 15 (FIG. ), the suspension member 11 and the parts to be cleaned 7dansla bathe bath cleaning liquid 1 until the cams 21 (Figure 2) abut on the flange 22 of the tank 1. During this movement of down, the bosses 23 of the levers 20 fix the parts 7 under the action of the weight of the frame 9 and the parts 7, while the electrodes 2 are approached parts cleaning parts 7 (the lower position of the frame is shown in phantom discontinued).

 The current pulses supplied by the generator 4 are applied to the electrodes 2 by the conductors 3, and there occurs in the liquid, between the parts 7 serving as negative electrodes and the positive electrodes 2, a series of high voltage electrical discharges. whose energy ensures the cleaning of castings.

 Once the cleaning of the parts 7 has been completed, the mobile frame 9 is raised out of the tank 1 to its upper position, the section 10 (FIG. 1) of the railtransporter 5 is again joined to the conveyor 6 and, after operation from the stop 18, the load carriage 15 is removed from the installation by the control channe and the following carriage carrying the parts to be cleaned is driven in its place in the installation.

 The molding sand and core sand removed is deposited at the bottom of the bath and is evacuated by known methods according to its composition and size.

Claims (3)

R E V E N D T C A T IO N S  1.- Installation for the electrohydraulic cleaning of castings, of the type comprising a tank (1) with a bath of cleaning liquid in which electrodes (2) are arranged connected to at least one generator (4) of pulses of current, and which is mounted under the carrier rail (5) d> a conveyor air (6) pushers for transporting the castings (7) attached to the suspension members (11) and a device for supplying parts casting machine (7) in the vessel (1) in the form of a movable frame (9) connected to a frame (8) and provided with a fixing member for the casting parts (7), characterized in that the frame (9) is rigidly connected to the section (10) of the conveyor rail (5) of the air conveyor with pushers (6), which is arranged directly above the tank (1) of the cleaning liquid bath, the device supplying the casting parts (7) into the tank (1) comprising a mechanism for vertically moving the frame (9) c together with the suspension member (11) of the conveyor (6) and with the casting (7), this mechanism allowing, when the frame (9) is in the upper position, to join the conveyor (6) said section rail bound to the frame (9), and said fixing member of the castings (7) attached to the suspension members (11) being in the form of a clamp (19).  2.- Installation according to claim 1, characterized in that the electrodes (2) are fixed on the clamp (19)  3.- Installation according to one of claims 1 and 2, characterized in that the clamp (19) is formed as two levers (20) with two arms, one arm of each lever (20) being endowed a cam (21) which, in the upper position of the frame (9), comes into contact with the frame (8), and in the lower position of the frame (9), with the flange (22) of the tank (1) , the other arms of the levers (20) having bosses (23) serving, in the lower position of the frame (9), to fix the casting (7) under the action of the weight of the frame (9) and the workpiece foundry (7).