GB2219233A

GB2219233A - Apparatus for electrohydraulic cleaning of castings

Info

Publication number: GB2219233A
Application number: GB8813136A
Authority: GB
Inventors: Vladimir Petrovich Zavoda; Ivan Ivanovich Fedorenko; Evgeny Ivanovich Solomatin; Spartak Anatolievic Petrusenko; Alexandra Borisovna Tolstykh
Original assignee: PK BYURO ELEKTROGIDRAVLIKI AN
Current assignee: PK BYURO ELEKTROGIDRAVLIKI AN
Priority date: 1988-06-03
Filing date: 1988-06-03
Publication date: 1989-12-06
Anticipated expiration: 2008-06-03
Also published as: FR2632550B1; GB8813136D0; DE3820414A1; GB2219233B; FR2632550A1

Description

APPARATUS FOR ELECTROHYDRAULIC CLEANING OF CASTINGS The invention relates

to apparatuses for electrohydrau- lic cleaning of castings.

The invention may be advantageously used in lot. large- -lot and mass production of castings for getting these rid of cores and residual moulding sand.

The conventional techniques of castings cleaning make wide use of vibratory apparatuses in which destruction and removal of cores and residual moulding sand occur under the action of vibration. Also used at present are hydraulic apparatuses in which cores and residual moulding sand are removed under the action of a high-pressure water jet, as well as electrohydraulic apparatuses wherein cleaning of castings placed in a liquid occurs under the action of shock waves and hydraulic streams generated in liquid due to a high-voltage electric discharge between an electrode and a casting.

Apparatus for electrohydraulic cleaning of castings feature cost effectiveness. high output and good quality of cleaning of intricately shaped castings from cores of any strength,, and enhanced labour conditions as compared with apparatuses of other types.

However, the problem of efficient disposal of wastes formed in the process of cleaning castings, such as slime. scrap and core reinforcement has not been solved heretofore in electrohydraulic apparatuses designed for operation in large-lot and mass production plants.

One of the main requirements imposed upon apparatuses for cleaning of castings is an enhanced output of the cleaning process.

4- 3" Known in the art is an apparatus for electrohydraulic cleaning of castings,comprising a bath containint. a liquid, a plurality of electrodes positioned to cover vital points of a casting (facilitating the best conditions of cleaning), a mechanism for moving the electrodes, a pulse current generator coupled to the electrodes, a means for feeding castings into the bath, and a means for disposal of _wastes formed in cleaning the castings, in particular, slime, from the bath (DE, C, 2141174). In this apparatus, the means for feeding castings to the bath comprises a pair of lift sections mounted on guide members positioned at an angle with respect to each other. This design is aimed at enhancing the apparatus output owing to the fact that the operations of feeding castings to be cleaned into the bath and unloading of the cleaned castings are carried out simultaneously.

However, no efficient removal of large-size wastes of casting cleaning in the form of lumps of cores, scrap and core fittings is ensured in this apparatus. While small-size wastes in the form of slime are removed from the bath by a pump, large- size wastes accumulate in the bath during cleaning of castings, and it is necessary to discontinue the apparatus operation to remove them. The bath is cleaned by using special devices or manually, which adversely affects the apparatus output.

Known in the art is an apparatus for electrohydraulic cleaning of castings, comprising a bath containing a liquid and horizontally extending guide members secured to a base on either side of the bath. The middle portion of the guide I; members is located on a lift section. Driven platforms carrying pallets for castings are mounted on the guide members. The apparatus also comprises a plurality of electrodes provided with a means for moving the electrodes and a pulse 5 generator coupled to the electrodes (SU, A, 552756).

In this apparatus. the platform carrying the pallet with a casting is rolled onto the lift section and lowered into the bath wherein the electrodes are moved close to the casting, and the casting is cleanad. At the same time, the foregoing pallet is first unloaded from the cleaned casting and then loaded with a new casting to be cleaned. After the cleaning is over,, the lift section is moved to assume the upper position, the pallet with the casting on the platform is rolled out of the lift section, and the pallet carrying a casting to be cleaned is moved to replace it. This appara tus makes it possible to carry out unlnading of the cleaned casting and loading of a casting to be cleaned on the pallet simultaneously with cleaning of a casting in the bath so as to enhance the output of the apparatus.

However. no efficient removal of scrap and core rein forcement accumulating in the bath and on the pallets is ensured in this apparatus. For the purpose of cleaning of the bath and the pallets, the apparatus is to be stopped, the cleaning is done either manually or with the employment of special devices. which impairs the output of the apparatus.

Also known in the art is an apparatus for electrohydraulic cleaning of castings, comprising a base on which there is mounted a bath having vertically extending guide members supporting a lift section for feeding castings into the bath having a reciprocation drive, a means for loading castings into the lift section comprising horizontally mounted circular guide members having a portion secured tn the base and a portion secured to the lift section, and driven load-carrying platforms mounted on the circular guide members and having pallets for castings, and at least one electrode having drives for moving it in a horizontal plane and a vertical plane and electrically coupled to a pulse ge- nerator (US, Aq 4198995).

In this apparatus castings are loaded on the pallet which is moved by means of the driven platform to the lift section along horizontally arranged guide members, the lift section being in the upper position. The lift section with the platform and the pallet is then lowered into the bath wherein the electrodes are moved close to the castings to carry out cleaning. The next pallet is loaded with castings, and the pallet with the castings that have been cleaned before is unloaded at the same time during cleaning. When the cleaning cycle is over, the electrodes are retracted from the castings, the lift section is moved back to the upper position, the portions of the circularguide members are brought in alignment, and the platform with the pallet carrying the cleaned castings is moved to the unloading station.

At the same time, the next pallet carrying castings to be cleaned is moved to the lift section.

Loading of the pallet, cleaning of the castings and unloading. of the cleaned castings are carried out simultaneously in the abovedescribed apparatus because each step is 4 carried out on a certain portion of the circular track. with a transfer between these portions being ensured simultaneously. The apparatus is the most productive one among all state of the art apparatuses for electrohydraulic clean5 ing of castings.

However, similarly to the abovedescribed apparatuses, no efficient disposal of large-size wastes in the form of lumps of cores, scrap and core reinforcement is ensured in this apparatus. It will be apparent that the apparatus is to be stopped for removing such wastes and the wastes should be removed manually or by means of special devices for cleaning the bath. At the same time, to remove wastes accumulating on the pallets, the pallets should be withdrawn from the apparatus and transferred to a place of waste disposal and then back to the apparatus, the pallets being cleaned manually or by means of special auxiliary devices, all this resulting in that the output of the apparatus is reduced.

It is an object of the invention to provide an appara- tus for electrohydraulic cleaning of castings featuring an enhanced output.

This object is accomplished by that an apparatus for electrohydraulic cleaning of castings, comprising a base on which there is mounted a bath having vertically extending guide members supporting a lift section designed for feeding castings to the bath and having a reciprocating motion drive, a means for loading ca stings into the lift section comprising horizontally arranged circular guide members having a portion secured to the base and a portion secured to the lift section, driven load-carrying platforms mounted on the circular guide members and having pallets for castings, and at least one electrode having drives for moving it in a horizontal plane and a vertical-plane and electrically coupl- ed to a pulse current generator. according to the invention, is provided with a means for disposal, from the pallets, of wastes formed in the process of cleaning the castings. which means is provided on the portion of the circular guide mem bers which is secured to the base.

This construction of the apparatus for electrohydraulic cleaning of castings makes it possible to carry out simultaneously cleaning of the castings in the bath, loading of the castings on the next pallet,, unloading of the castings from the foregoing pallet, and removal of wastes formed during cleaning of the castings, from the pallet, the provision of the means for removing wastes formed during cleaning of the castingsq from the pallet, mounted on the portion of the circular guide members which is secured to the base allows wastes formed during cleaning of the castings to be removed from the pallets without the need to remove the pallets and transfer them to a place of waste disposal and then back to the apparatus. the employment of auxiliary devices or manual labour for cleaning the pallets being dispensed with thus enhancing the output of the apparatus.

It is preferred that in an apparatus for electrohydrau lic cleaning of castings the pallets be attached to the platforms by means of pivot joints, and the means for dis posal of wastes formed in the process of cleaning the cast ings. from the pallets. is made as a mechanism for turning 1 the pallets in a vertical plane with respect to the platforms.

This construction of the means for removing wastes formed in the process of cleaning the castings, from the pallets, makes a mechanism for turning the pallets simple in its kinematic scheme and reliable, thus enhancing reliability of the apparatus in operation.

It is also preferred that in an apparatus for electrohydraulic cleaning of castings the pallets be constituted by vertically extending plates spaced from each other and connected to each other by means of horizontally arranged rods, and plates having a trapezoidal-shaped cross-section, each being mounted in the gap between the vertically mounted plates and pivotally connected through one end to the rod which is most remote from the pivot joint that attaches the pallet to the platform.

This construction of the pallet ensures necessary st--ngth and resistance to impact loads occurring during electric discharge in liquid, and a reduced metal consumption.

The provision of the plates having a trapezoidal-shaped cross-section prevents large-size wastes from getting to the bath so as to avoid frequent stops of operation of the appa ratus for cleaning the bath, and enhances the apparatus output.

The pivotal attachment of the plates through one end thereof to the rod which is most remote from the pivot joint that attaches the pallet to the platform allows the plates to turn under the action of inertia forces after the pallet has stopped so as to contribute to a more efficient cleaning of the pallet from wastes formed in the process of cleaning the castings and sticking to the pallet.

It is further preferred that in an apparatus for electrohydraulic cleaning of castings the mechanism for turning -5 the pallets in a vertical plane with respect to the platforms also- comprise a spring-biased stop secured to the base and positioned in such a manner that when the pallets assume the topmost position by turning them in a vertical plane, they engage the spring-biased stop to impart oscilla- tions to the pallets and free ends of the plates having trapezo-4dal- shaped cross-section. Thisfacility ensures a more efficient cleaning of the pallets from sticking wastes formed during cleaning of the castings.

"he pallet rods in the apparatus for electrohydraulic cleaning of castings are preferably in the form of tie-up pins and are provided with bushings positioned in the gaps between the vertically extending plates and with elastic members insert ed between the faces of the bushings and the vertically extending plates.

This construction allows the pallet to be made without welded joints acting, in fact, as concentrators of stresses, which makes it possible to improve resistance of the pallet to impact loads owing to deformations of the elastic mem bers and to enhance reliability of the apparatus in operation.

The invention will now be described in detail with reference to specific embodiments illustrated in the accompanying drawings, in which:

Fig. 1 is a schematic representation of an apparatus for electrohydraulic cleaning of castings in a longitudinal section vieiv,, according to the invention; Fig. 2 is same of Fig. 1, a plan view; Pig. 3 is a sectional view taken along the line III-III in Fig. 2; Fig. 4 is a sectional view taken along the line IV-IV in Fig. 3; Pig. 5 is an enlarged detail A of a pallet shown in Fig. 4.

With reference to Fig, 1, an apparatus for electrohydraulic cleaning of castings comprises a base 1 on which there is mounted a bath 2 having vertically extending guide members 3 supporting a lift section 4 adapted to feed castings 5 to the bath 2. The lift section 4 has a reciprocating motion drive 6. In this embodiment the drive 6 is in the form of a hydraulic cylinder, but other drives, e.g. a cable drive, may also be used. The apparatus incorporates a means for loading the castings 5 on the lift section 4, which is embodied as horizontally mounted circular guide members 7 (Fig. 2). The circular guide members 7 have a portion 71 secured to the base 1, and a portion 72 (Fig. 1 secured to the lift section 4, the portions being made in the form of rail tracks. Mounted on the guide members 7 (Fig. 2) are driven load-carrying platforms 8 (Fig. 1) having pallets 9 for castings.

In this embodiment. the drive of the load-carrying platforms 8 is in the form of a cross 11 pivotally mounted on the base 1 of a pin 10 and having grippers 12 (Fig. 2) engageable with pin stops 13 secured to the platforms 8, and a hydraulic cylinder 14 (Fig. 2) secured to the base 1 and coupled to the cross 11 by means of a gear train 15 (Fig. 1). Other embodiments of the drive for moving the 5 load-carrying platforms may also be used.

The apparatus for electrohydraulic cleaning of castings also comprises at least one electrode. and in this embodiment it has three electrodes 16 having drives 17 for moving them in a vertical plane and a horizontal plane (one drive 17 only is shown for the sake of clarity). The electrodes 16 are mounted on a sound insulating slab 18 and are electrically coupled to pulse current generators 19. This arrangement makes it possible to enhance intensity of cleaning the castings. One. two or more than three electrodes 16 may also be used in the apparatus.

The apparatus also comprises a means for removing wastes formed in cleaning the castings, from the pallets 9, which is mounted on the portion 71 of the circular guide members 7 (Fig. 2) which is secured to the base 1 (Fig. 1).

In this embodiment of the apparatus for electrohydraulic cleaning of castings, the means for removing. from the pallets 9, of wastes formed in the process of cleaning the castings comprises a mechanism 20 for turning the pallets in a vertical plane with respect to the platforms, and, in particular, a linkage which is secured to the base 1, on a portion 21 (Fig. 2) of the circular guide members 7 which is opposite to the bath 2 (Fig. 1), between a portion 22 (Fig. 2) of the circular guide members 7 at a station of loading of castings to be cleaned and a portion 23 of the 1 1 1 circular guide members 7 at a station of unloading of the cleaned castings. The mechanism 20 for turning the pallets with respect to the platform is connected to a hydraulic cylinder 24 (Figs 1, 3) secured to the base 1 and comprises a roller 25 engageable with the pallet 9. The pallets 9 are attached to the platforms 8 by means of pivot joints 26.

Other embodiments and arrangements of the means for disposal of wastes formed in the process of cleaning the castings, from the pallets, may be used; such means may be ar- ranged, e.g. on the portion 23 (Fig. 2) of the circular guide members 7.

It is preferred that each pallet 9 (Fig. 3) be made in the form of vertically extending plates 27 spaced from each other as shown in Figs 4, 5. The plates 27 are connected to each other by means of horizontally mounted rods 28. The pallets 9 (Fig. 3) aloo comprise horizontally extending plates 29 having trapezoidal- shaped cross-section, each plate being positioned in the gap between the plates 27 (Figs 4, 5) and having one end pivotally attached to the rod 28 (Fig. 3) which is most remote from the pivot Joint 26. The rods 28 are made in the form of tie-up rods and are provided with bushings 30 (Figs 4, 5) mounted in the gaps between the plates 27 and with elastic members 31 inserted between the end faces of the bushings 30 and the plates 27 (Figs 4, 5). Other embodiments of the pallet, e.g, with the use of welded joints are also possible.

The mechanism 20 for turning the pallets (Fig. 3) with respect to the platforms also comprises a spring-biased stop 32 which is secured to the base 1 by means of a post 33 and which is positioned in such a manner that when the pallets 9 are urged to assume the topmost position shown by dash-and-dot line when turned in a vertical plane, they en.gage the spring-biased stop 32 to impart oscillations to the pallets and the free ends of the plates 29 having trapezoidal-shaped cross-section. In addition, the apparatus has a ramp 34 (Fig, 1) along which wastes 35 of the cleaning process pass to a belt conveyor 36.

The apparatus for electrohydraulic cleaning of castings functions in the following manner. A casting is fed onto the pallet 9 (Fig. 1) mounted on the platform 8 which is located on the portion 22 (Fig. 2) of the circular guide members 7 from a works-hop conveyor (not shown in the drawings). The cross 11 (Fig. 1) is turned through 9011 by the hydraulic cylinder 14. The grippers 12 engage the pin stops 13 of the load-carrying platforms 8 to move them along the circular guide members 7. As a result of rotation of the cross 11 through 900. the load-carrying platform 8 carrying the casting is placed on the lift section 4. and the next load- -carrying platform 8 (Fig. 1) carrying the pallet 9 is placed on the portion 22 (Fig. 2) of the circular guide members 7.

The drive 6 of the reciprocating motion-operates whereby the lift section 4 supporting the platform 8 carry- ing the pallet 9 with the z_asting 5 and the portion 72 of the circular guide members mounted on the lift section 4 is submerged into the bath 2 filled with water. The electrodes 16 placed at vital points are moved close to the casting 5 by the drives 17, the pulse current generator 19 1.

is switched on, and the castin6's 5 are cleaned. After the cleaning is over, the lift section 4 is raised by the bydraulic cylinder back to the initial position, and "Ube portions 721 71 of the circular,,ruides 7 (Fig. 2) mounted on the base I (Fig. 1) and on the lift section 4 are brout;ht in alignment.

Simultaneously with the EbDvedescribed operations, the pallet 9 located on the load-carrying platform 8 mounted on the portion 22 (Fig. 2) of the circular guide members 7 is 10 loaded.

The Cross 11 is aFain rotated through 90 by the byd- raulic cylinder 14. The load-carrying plaftr.,_ 8 carrying v v the cleaned castint--s 5 is transferred to the Portion 23 of 0 the circular,uide meiEbers 7, and the load-carrying plat form 8 (Fig. 1) carrying the castim-,, 5 to be cleaned is transferred from the portion 22 (FiF,. 2) of the circular guide menibers 7 to the lift section 4, and a next load -carrying platform 8 (Fi;. 1) carrying the pallet 9 is fed to 'Ube portion 22, whereafter the steps of unloading of the cleaned castinGs 5 to a vjDrksbop Conveyor (not shown) on the portion 23 of the circular guide members 7 (Fig. 2), cleaning of the castings 5 (Fig. 1) In the bath, and loadinj of the next castings 5 to be cleaned on the PD2tiDn 22 (Fig. 2) will be simultaneously carried out.

When these steps are over and when the lift section 4 has been raised, the cross 11 is ajain rotated through 90 The platform 8 (Pi-,ure 1) carrying the pallet 9 co-"tainino.

j L, cj -14wastes 35 of cleaninc in the forr- of scrap, Iumps of cores and core reinforcement is transferred to the Portion 21 of the circular guide members 7 (Pi,7ure 2). The roller 25 3) of the rotation mechanism is pressed by the hyd raulic cylinder 24 against the bottom of the pallet 9 to turn it about the pivot joint 26 in a vertical plane until it eni.ages the spring-biased stop 72. The pallet Q oscillate SO as to facilitate Linloadin- the vastes of cleaning.

The wastes '5 are fed along the ramp 34 (Figure 1) to the Workshop belt conveyor 36. The free ends of the plates 2c,having trapezoidel-shaped cross-section of the pallet 9 rotate about the rod 28 which is most remote from the --ivot joint 26, simultaneously v.ith the pallet Q, and oscillate. This contributes to an intensive cleaning of the plates 29 -es of cleaning in the form of slime.

fro= sticking the wast fter The pallet c,' is moved back to the initial position a.. the cleaning. At the same time. the next castin,.;s-- ) to be cleaned are loaded on the portion 22 of the circular guide members 7 (Pi,:,ure 2)q the foregoing castin-, 5 is cleaned W c 1:i in the bath 2 (Figure 1), and the cleaned c,-stin,1-;-) is unloaded on the Portion 23 of the circular guide menberp 7 (Figure 2).

b'v'ben these simultaneously performed operations are over, the cross 11 is again turned through 901', ---n.l the -::.bDve- described cycle is repeated.

The apparatus i-or electrohydraulic cleaning of castings allows the output Of the process to be substantially C z enhanced owing to simultaneous performance of the steps of removal of wastes of the cleaning process, loading of castings to be cleaned, cleaning of the foregoing castingsand unloading of the cleaned castings from the apparatus. It is not necessary to discontinue the operation of the apparatus for cleaning the bath from wastes of castings cleaning and there is no need to transfer the pallets away from the apparatus to a place of waste disposal and then back to the apparatus. The employment of the apparatus for electrohydraulic cleaning of castings, according to the invention, improves labour conditions. The mechanism for disposal of wastes from the pallets is simple in structure and reliable in operation. The design-of the pallets ensures their resistance to impact loads thus enhancing reliability of the apparatus during a long-term operation.

Claims

WHAT WE CLAIM IS:

1. An apparatus for electrohydraulic cleaning of castings comprising a base supporting a bath having vertically extending guide members; a lift section mounted on the guide members adapted for feeding the castings into the bath and having a reciprocating motion drive; a means for loading the castings onto the lift section made as hnrizentally extending circular guide members having a portion secured to the base and a portion secured to the lift section, and driven load-carrying platforms mounted on the circular guide members and having pallets for castings; a means for disposal, from the pallets. of wastes formed in the process of cleaning the castings, which means is provided on the portion of the circular guide members which is secured to the base; at least one electrode having drives for moving it in a horizontal plane and vertical plane and electrically coupled to a pulse current generator.

2. An apparatus for elect rohydraulic cleaning of castings as claimed in Claim 1. -viherein the pallets are attached to the platforms by means of pivot joints, and the means for disposal of wastes formed in the process of cleaning the castings, from the pallets. comprises a mechanism for turning the pallets in a vertical plane ivith respect to the platforms.

3. An apparatus for electrohydraulic cleaning of cast ings as claimed in Claim 2. wherein the pallets are.consti tuted by vrtically arranged plates spaced from each other and connected to each other by means of horizontally 1 t, arranged rods, and plates having a trapezoidal-shaped cross-section, each being mounted in the gap between the vertical ly extending plates and pivotally connected through one end to the rod which is most remote from the pivot joint that 5 attaches the pallet to the platform.

4. An apparatus for electrohydraulic cleaning of castings as claimed in Claims 2, 3, wherein the mechanism for turning the pallets in a vertical plane with respect to the platforms also comprises a spring-biased stop secured to the base and positioned in such a manner that when the pallets assume the topmost position by rotating them in a vertical plane t'hey engage the spring-biased stop to impart oscillations to the pallets and the free ends of the plates having a trapezoidal-shaped cross-section.

5. An apparatus for electrohydraulic cleaning of cast- ings as claimed in Claim 3, wherein the rods of the pallets are in the form of tie-up pins and are provided with bushings positioned in the gaps between the vertioally arranged plates and with elastic members mounted between the faces of the bushings and the vertically arranged plates.

6. An apparatus for electrohydraulic cleaning of castings substantially as hereinabove described with reference to, and as shown in the accompanying drawings.

Published 1989 at The Patent Ofnce, State House, 86,71 High Holbora, London WCIR 4TP. Further copies maybe obtained from The PelentOfll0e Sales Branch, St Maxy Cray, Orpington, Rent BR5 3RD. Printed by Multiplex techniques ltd, St MarY Cray, 3Kent, Con- 1187 1 1 p 1 i 1