FR2642344A1 - ARRANGEMENT OF DEVICES FOR THE AUTOMATIC PRODUCTION OF FLAT CASTING MOLDS USING BINDLESS DRY SAND - Google Patents

Abstract

Sets of devices allowing in an automatic system the production of molds for flat casting using dry sand without binder, essentially composed of: - sand scraping and sweeping devices using the transfer movement of the frame between 2 operating stations and producing a bottom of a flat mold in the same plane as the edge of the frame and clearing the tops of the tool parts which must open out to facilitate subsequent cutting of the closing film, associated with ancillary devices for cleaning and recycling the excess sand; - a device for unwinding-cutting-laying the sheet of plastic film for closure provided with a sliding frame allowing it to pass through the arms of a demoulding-transfer device for half-molds; - a transfer trolley and gates allowing manual finishing to be carried out outside the molding area.

Description

2642344-

  The present invention, relating to the foundry, relates to a set of devices allowing the production, in an automatic system, of molds for flat casting.

  using a sand without binder according to the process known as vacuum molding.

  Foundry molds are traditionally made according to this process in 2 parts consisting of a lower half-mold and an upper half-mold which after assembly

contain the molding imprint.

  A model plate comprising the shape of the half-impression is placed on a box connected to a vacuum source; the whole forms a closed volume and the surface of the model plate is porous or pierced with fine holes connected to the surface lower of the

plate.

  A heated plastic sheet is then placed on the model plate where it is thermoformed and follows the shapes of the model plate under the effect of the suction through the holes or the porosity of the model plate; model plate coated with its plastic sheet called contact plastic is placed a frame, made up of a bottomless box whose inner side walls are porous to air and impermeable to sand; the frame is then filled by gravity with sand natural dry without binder up to the level of its upper surface, with vibration during filling to ensure good

densification of sand.

  A second sheet of plastic, called closing plastic, of a size slightly larger than the internal section of the chassis, is then placed on the upper surface of the

sand, opposite side 6 footprint.

  The connection of the chassis to a source of vacuum then ensures cohesion by tightening the grains of sand in the volume delimited by the plastic contact sheet, the walls

  interior of the chassis and the plastic sheet of iron.

  This assembly (ehassis, sand, plastic contact and closure sheet) which remains compact enough that the chassis is connected to a sufficient vacuum source, constitutes the half-mold, the shape of the half-footprint being given at the start during thermoforming

  of the plastic contact sheet on the model plate placed on the box.

  The union of the 2 half-molds, as with the other Casting mold casting processes in chassis-compacted sand, constitutes the mold, a mold which remains compact due to the clamping effect of the sand between the impression sheet and the closure sheet if mold chassis

  are permanently connected to a source of vacuum.

  The advantages which result from the process are well known: strong reduction in noise nuisance compared to green sand clamping processes, simplified sorted sand circuit and almost total recovery of the molding sand without any other operation than sieving and

possible cooling.

  As with the other chassis molding processes, 2 molding and filling methods can be carried out, each having advantages and disadvantages depending on the orientation of the half-cavity contact plane when filling the metal or liquid alloy imprint. commonly molding joint - or molds for "standing flat-casting molding", which means that in the standby position before filling with the liquid alloy the molding joint is vertical and the openings in the cavity for the filling and for the parts to lead into

  the atmosphere (ventsmasselottes) are in the plane of the molding joint.

  - or molds for "flat molding-flat casting", the molding joint in the standby position before filling then being horizontal (or slightly inclined relative to the horizontal if the mold is placed for technical braking reasons or acceleration of the liquid metal in certain parts of the cavity, on an inclined plane) and the openings in the cavity for filling and for the parts which must open into the atmosphere are then located on the surface of the half-mold where the closing plastic sheet is placed, the axis of the pouring descent and the

  the imprint which should lead to the atmosphere is then perpendicular to the molding joint.

  The choice between the 2 methods which each have their advantages and disadvantages is guided by technical considerations related to the shape and size of the parts, the nature of the alloy, the degree of automation of the molding process; in the case of vacuum molding , the advantages and disadvantages between flat casting and standing have a common part with the other sand clamping methods and their own particularities

  to the sand clamping mode by the vacuum.

  In the case of "standing flat-casting molding", the production of the imprint is facilitated by: - the possibility of obtaining in the vast majority of cases the form of "appendages" such as funnel and descent of casting, vents, weights , directly "naturally" during the thermoforming of the contact plastic sheet, this shape being integrated into the shape

  of the half-impression on a model plate.

  the absence of openings in the imprint opening on the lateral surfaces of the mold in the casting position, surfaces which are the upper surfaces of the chassis during molding. The chassis must have an inclined side wall or with fixed openings (in the case where the funnel and downpipe and appendages always open out in the same place) in order to allow the corresponding parts of the impression to open out during filling. As with the other conventional methods, the surface area occupied by a standing cast mold is smaller than for a flat cast mold, which allows, with equal production capacity and casting rates, to have casting surfaces clearly more

reduced.

26.42344

  The shape of the surface on which the closing plastic sheet is pressed does not have to be precise and flat since it has no functional role of bearing on the surface of the floor of the rolled area; it will most often be, in an automatic installation with filling by cover hopper such as that described in European patent nOOl 4226B1, that which results from the end of the operation, ie a juxtaposition of

small sand domes.

  The chassis must, however, have, in addition to their internal surface which is porous to the air and impermeable to sand and in the case of the closure of the surface opposite to the imprint by a sheet of plastic - the most common arrangement and pretending to be more easily at

  automatic filling of the sand with a hopper in an automatic installation

  hollow sand-tight and air-permeable tubes arranged transversely parallel to the surface opposite the molding footprint so as to be able to ensure sufficient cohesion of the sand when the mold is in the casting position, upright, to resist lateral pressures resulting from the weight of the sand and the thrusts of the alloy during filling; this arrangement of tubes does not allow the separation of sand-piece-chassis traditionally called unhooking with such a simple process

  than that described in patent application No. 8807324.

  The mold must also be kept permanently connected to the vacuum source, even after filling and solidification of the metal and as long as the mold is standing in the filling position to avoid the fall of the sand: the mold must be permanently connected to

  the source of vacuum until complete separation of the chassis-solidified part-sand.

  This arrangement causes, 6 identical production capacity and casting rates, an oversizing of the vacuum production unit compared to molds cast flat o the mold, while awaiting its resumption for release, can be disconnected from the vacuum source as soon as the piece is sufficiently solidified without risk of falling sand which is retained in the volume between the ground of the pouring area and the walls

interior of the chassis.

  When the size or shape of the pieces to be made their massive or strong

  thicknesses and / or the nature of the alloy to be cast - and particularly in the case of steel -

  requires a high weighting rate of the feeding system to obtain healthy solid parts without porosities during the solidification withdrawal, which frequently requires large weightsThe "flat molding - standing casting" method is limited because the size of the sections of weights are very often greater than one of the

  dimensions of the lateral section of the chassis.

  These last 3 drawbacks (more complex release system due to the presence of transverse tubes in the 2 large chassis parts dimensioning of the deprersion production plant due to the vacuum maintenance of the rr, oulAs present on the casting area - before repacking, during filling and after filling. Limits on the parts to be produced in the event of massive parts and / or alloy grades requiring a high rate of weighting) lead to prefer the second step called "flat molding - casting È flat ". Another advantage of "flat molding - flat casting" using the clamping of the sand by the vacuum effect is the possibility of removing the connection of the mold with the vacuum source as soon as the part is sufficiently solidified, both to save on the dimensioning + of the vacuum production plant and its energy consumption, but above all because the sand is no longer hardened by the vacuum tightening effect, the cooling accompanied by a contraction shrinkage of the metal, often critical with grades of alloys such as special steels and / or with parts having mass parts connected together by thinner parts, shrinkage generating defects called, "oriqusse of withdrawal in, a mold whose sand remains rigid until '' to the stall, is then carried out in a refractory but not rigid medium which accompanies the withdrawal

dirmensional without upsetting him.

  Av- * 1st sy + "flat molding - flat casting" system in vacuum molding, the frames do not have a tube: t-ansersau>, at least in the lower ohasis in contact with the ground of the cooking area, which allows the use of a simple deoochage system and

  qenerator of advantages such as that described in patent application nC8807324.

  In addition, the realization of the fingerprint, in particular in an automatic system where the annual interventions must be, for reasons of productivity and security, limited in duration and carried out at specific locations, is more complex; -the bottom of the lower half-mold, part in contact with the ground of the pouring area, must be flat and in the same plane as the surface of the upper edge of the frame, this in order to be able to remove the connection of the mold at the source of vacuum as soon as the part is partially solidified without causing localized deformations of the mold and

so possibly piece.

  -the 2 surfaceE of the upper half-mold - half-cavity and top must be accessible to an operator after demolding and before re-molding with the lower half-mold in order to be able to carry out manual finishing operations, the most important of which are the cutting of the plastic sheet for closing in line with the parts of the track + e which must open (funnel and descent of casting, vents, weights) with recovery of the forms of tool used to make these parts of the imprint,

264-2344

  these imprint parts being in fact impossible to obtain naturally either because they are strongly undercut relative to the direction of demolding or also because they would most often lead to too strong a stretching of the plastic film of contact

  during thermoforming on the model plate causing the film to tear.

  During this operation, the parts of impression having to open must, to ensure the cutting of the plastic of closure without defects and the recovery of the tools,

  be visible and not covered with sand, even in very thin layers.

  For these reasons of greater complexity of making the imprint, the automatic systems existing to date for molds cast flat were hampered in productivity due to the need for operator intervention in the molding area or the degree was lower than on mold installations

poured standing.

  The present invention describes a set of simple devices making it possible, in an automatic system for flat molds, to carry out the operations described above with manual intervention limited to the strict minimum for reasons of productivity and in an area where demoulding is completed and where these operations stop

  not the continuation of other automatic molding operations.

  This set of devices allows: - the automatic installation, without any manual intervention, of the lower half-mold with its perfectly flat bottom and in the same plane as the lower edge of the chassis on an automatic transfer equipment accessible to operators outside the area molding for finishing operations such as removal of cores, identification marking

  on imprint, recovery of removable parts of undercut models, etc ...

  -access, in complete safety and before re-molding, to the 2 surfaoes, half-cavity side and top side, of the upper half-mold for the operations of recovering the forms and tools used to make the unblocking parts of the impression (lowering of casting , weights, vents) with total visibility of the parts of the closing plastic sheet to be cut, a sheet which, at the places to be cut rests on sand-free surfaces; this access before rewinding allows other advantageous operations to be carried out such as the possibility to nail cores in the upper half-mold, recovery of removable parts of undercut models thus greatly simplifying the technical design of the shape of the impression compared to the final shape

of the part to be obtained.

  These devices, integrated into a complete automatic molding assembly, comprise a scraping system systematically eliminating, before removing the closing plastic sheet and whatever the type of half-mold to be produced, the excess sand on the opposite side surface at the half-footprint, thus making it possible to

  lower half-mold with flat bottom in the same plane as the lower edge of the chassis.

  -a sweeping system, posterior to the scraping system, which acts in the case of the top of an upper half-mold to remove excess sand on the tools making the imprint forms to open, sweeping carried out before removing the closing plastic sheet; the upper plastic sheet will therefore rest on

  sand-free faces where it should be cut.

  -a device unwinder-cutter-installer of the closing plastic sheet passing between the arms of the release device-transport of half-molds and / or chassis; this device automatically performs the removal of the synchronized closing plastic sheet with the request of the demoulding-transport device for half-molds and / or chassis -a trolley provided with a lifting table for removing the lower half-mold, comprising 2 automatic pick-up points and associated with a set of gates automatic, allowing the completion of finishing operations on the lower half-mold outside the mold area and outside the work area of the mold release-transport device for half molds

and / or chassis.

  -a device for cleaning excess sand redeposited on the zibrating table during scraping and / or sweeping operations and a device for recovering all the excess sand after filling of the

  chassis and recycling in the chassis filling hopper.

  According to an advantageous but non-limiting embodiment, the systems

  m: scraping, sweeping the top of the upper half-mold, cleaning

  the vibrating table are partially static and use the movement

  25.ent relative automatic transfer of the chassis between its position at

  filling-vibration station and its position at the demolding station.

  An example of a preferred but non-limiting embodiment is

  described in more detail with reference to the accompanying drawings.

  The accompanying drawing Figure n 1 shows, in top view, a schematic and simplified overall arrangement of the molding system and the situation

  of the various devices of the present invention.

  In this drawing, the assembly marked 1 is a carousel with 4 stations, each station being able to carry a box (or "Vacuum Box") with a model plate placed on it; this arrangement is very commonly adopted in molding of

  preference to other transfer systems because it allows a work so-

  multane at each station when the carousel is stopped and a transfer if-

  multane from one station to the next operating station during the rotation of the carousel, which ensures maximum productivity provided that the operating times at each station are close, with a transfer movement

simple assured by rotation.

  When the carousel is stopped at the end of the transfer, each station occupied

  eg a position corresponding to one or more predefined operations.

  The position marked a corresponds to a position where the boxes carrying model plates and connected to the vacuum network by a set of sheaths connected upstream on a rotating joint passing through the center of the carousel, can be extracted from the carousel thanks to a table breeder spotted 2 equipped

  of rollers ordered and transferred to a trolley marked 3 located outside the carriage

  salt to facilitate preparation-tool change operations-

  ge, setting up of the parts used for the imprint forms which should open out for the upper half-mold (casting, weights, vents, ...). The mobile frame of the device identified 4 used for the removal of the contact plastic sheet when the box is on the station a comes in the position of deposit directly above the station a,

  The position marked b corresponds to a position where the release device

  lage-transfer of chassis and half-molds identified 5 comes to deposit a chassis.

  The position marked c corresponds to a position where filling takes place.

  ssage and vibration of the sand of the half-mold, thanks to a raised table

  vibrating rod lifting the box-plate-model-chassis assembly to press it against the flexible seal at the bottom of a filling hopper

  marked 12 of the type of that which is the subject of the invention patent n EP 0014226B1.

  The position marked d corresponds to a position where the closing plastic is applied by the unwinder-cutter-installer device of the closing plastic film sheet, device marked 6, and 1 '

  removal of the half-mold by the device identified 5.

  The assembly identified 7 corresponds to the device for scraping excess sand from the upper or lower half-molds (part of sand at

  above the upper level of the chassis).

  The assembly marked 8 corresponds to the scanning device for removing

  removal of excess sand on the tools of the upper half-molds used to produce the parts of the impression which should open (lowering of

casting, weights, vents ...).

  In the figure n'l are also shown diagrammatically: the upper edges of the hopper of the device for recycling the

excess sand, identified 11.

  -8- -a part of the fixed security barriers preventing access to the

  carousel in automatic operation, marked 18.

  -the carriage marked 19 used for the transport and transfer of the half

molds and complete molds.

  -the set of automatic gates marked p3 to allow access to operators: on the lower half-mold or on the complete mold when the carriage 19 is outside the travel zone of

the device identified 5.

  10. on the upper half-mold, held by the identified device and presented in a vertical position excluding the carousel, to

  finishing operations on the 2 surfaces of the half

upper mold.

  The attached drawing Figure n 2 corresponds to a side view and

  simplified schematic according to section I-II of the attached drawing in figure nl1.

  On this diagram, the vibrating lifting table is marked 9.1 ''

  marked 10 fixed on each of the arms of the box body supports

  salt corresponds to the device for cleaning excess sand which has fallen onto the vibrating table, and the assembly marked 11 represents the device for recycling excess sand in the spotted filling hopper

  The arrow pointing to the mark x shows the connection of the round joint

  from the carousel towards the source of depression.

  The accompanying drawings in figures n 3,4,5 represent the devices marked 7 and 8 in more detail: FIG. 3 is a top view of the 2 devices 7 and 8, FIG. 4 a side view of the 2 devices

  in action after cutting along an axis perpendicular to the axis of pivo-

7b.

  In this figure n'4, the 2 devices are shown in action and the upper part of a chassis is figured, the dotted dashed line indicating the shape of the upper surface of the sand, succession of domes before leveling by the sheet marked 7e du device 7, then plane and in the same plane as the upper edge of the chassis after leveling, then plane and slightly below the plane of the edge of the chassis and releasing the upper parts of the mold which should open up after scanning by

the brushes 8a of the device 8.

  The arrow shows the direction of advance of the chassis during the rotation of

  transfer of the carousel from station c to station d.

  Figure 5 is a partial section along the axis of the part marked -9-

  8b of the device marked 8 showing the details of the lifting system

  lowering of the active part of the device 8 and of the level adjustment as well as the fixing of the active part on the lifting device; the double arrow in this figure corresponds to the arrival or the bleeding of the compressed air for inflation or deflation of the inflatable stops 8e. According to a preferred but nonlimiting embodiment, the device marked 7 as a whole consists of 2 metallic connecting pieces marked 7a each articulated around an axis

  marked 7b and fitted with return springs marked 7c.

  The metal part marked 7a carries 2 rounded parts marked 7d, fixed to the part 7a by screws; the fixing position of the parts 7d is adjustable on the part 7a thanks to lights cut out on the parts 7d, the axes of the tightening screws pieces 7d on pieces 7a

passing through these lights.

  When the fixing position of the parts 7d on the parts 7a is correctly adjusted, the walls of the chassis come, at the start of the transfer rotation of the carousel from the position marked c to the position marked d, in contact with the rounded parts of the parts 7d of so that the edges of the chassis push back without catching the metal parts

  7a upwards by rotation around the axes 7b.

  On the 2 pieces marked 7a is fixed a sheet of shape marked 7e having an inclined part, sheet whose lower vertical level which constitutes the edge of the attack blade for leveling-scraping the sand is identical to the part of the rounded shapes 7d parts coming to the

  contact of the edges of the chassis at the start of rotation.

  When the device identified 7 is in action the angle of inclination

  of the inclined part of the sheet marked 7e with respect to the horizontal plane

  zontal of the upper edge of the chassis moving towards the sheet is higher

  laughing at 90, in order to prevent, in combination with the return torque of the springs marked 7c, the thrust of the sand from lifting the metal part

  7th above the level of the upper edge of the chassis during rotation.

  The length of the part 7e is calculated so that, during the transfer rotation from station c to station d, the entire upper section of the chassis, including the thickness of its edges, is in contact with the leading edge

from room 7e.

of each one

  The return torque / springs can be adjusted by means of adjustable stops.

  , fixed one on the support structure of the bearings of the axis of rotation

  (stop marked 7f) and the other on the part marked 7a (stop marked 7g).

  -10- A third adjustable stop marked 7h, fixed on the support structure limits the low position of the mobile assembly 7a-7d-7e before the chassis comes to bear on the parts 7d at the start of rotation, so

  to ensure that the chassis contact is made on the rounded parts

  dies of parts 7d without hooking. According to a preferred but non-limiting embodiment, the device marked 8 as a whole consists of a set of brushes with fairly rigid plastic lining (type "brush of

  roadmender ") marked 8a threaded in a solid and rigid metal profile

  that marked 8b and blocked at the 2 ends of the profile by a device

  quick locking device marked oc advantageously consisting of an eccentric cam

  that actuated by a lever; this device marked oc allows disassembly

  and a very rapid exchange of used brushes without any tools.

  The metal profile is fixed at its 2 ends to 2 plates marked 8d; these Sd plates are fixed on the upper part of inflatable stops

  marked 8e, inflatable stops, the base of which is fixed on a metal support

that spotted Sf.

  Threaded rods marked 8g, fixed by a set of locknuts marked 8h on the upper plate 8d, and which can slide through bores drilled in the metal support 8f of the inflatable stops

  carry sets of locknuts marked Si and 8j.

  The nuts-ccntre-nuts identified 8i limit the descent of the assembly 8aSb-Sd when deflating the stops and the nuts-locknuts

  marked 8j limit the climb stroke of the same assembly during inflation

  ge of the stops so as not to damage these stops.

  These 8i locknuts associated with 8g threaded rods allow

  easily adjust the lower level of the brush trim when

  that the stops are deflated and that the device marked 8 is therefore in the working position and to compensate for use the overall wear of the

  brush pads; the amount of sand swept varies approximately-

  linearly increasing from the end closest to the side of the chassis closest to the center of rotation of the carousel at the other end, a periodic reversal of the profiled assembly 8b and sesbalais Sa ensures almost wear constant of the linings of all the brushes and consequently a change of brushes at low frequency taking into account the useful length of the lining, which allows

  particularly low maintenance costs for the device identified 8.

  -11- The mobile assembly supported by the inflatable stops has a significant weight in order to ensure a sufficient sweeping force; the stops

  inflatable, which do not require any maintenance, have a stroke of

  few centimeters, limited by the locknuts marked 8i and 8j adjustable on the threaded rods 8g, sufficient so that when they are inflated the low level of the brush linings is above the upper plane of the chassis and when they are deflated the lower level of the fittings is below the upper plane of the chassis

from 1 to 2cm.

  Depending on whether the chassis which has just been filled at station c before trans-

  fert corresponds to a lower half-mold or an upper half-mold, the upper chassis plane constitutes in the first case the bottom of the lower half-mold and in the second case the top of the upper half-mold. In the first case, only the device identified 7 is actuated, the device identified 8 being in the high position by inflating the stops, and the sand is therefore leveled off at the same level as the plane of the upper edge.

  of the chassis before fitting the closing plastic which will ensure a half

  lower mold with flat bottom in the same plane as the edge of the chassis.

  In the second case, the 2 devices marked 7 and 8 are actuated, the device marked 8 being in the low position by deflating the stops; during the transfer rotation, the part of excess sand above the edge of the chassis - the most important part - is first removed by the device marked 7 then the device marked 8 sweeps a weak layer of sand of 1 at 2cm thus releasing from sand the upper parts of the recoverable or non-recoverable tools used to make the imprint forms that must open (weights, downpipe, vents), these upper parts of the tool must necessarily be located slightly below the level from the upper edge of the chassis to avoid being damaged at the start of the filling operation at station c, when the vibrating lifting table presses the vacuum box-plate-model-chassis assembly under the filling hopper, the edges of the chassis coming into contact with the flexible joint at the edge of

the filling hopper.

  When, during the transfer, a tool for an impression form which has to open comes into contact with the brushes' linings, the linings are flexible enough to be repelled by the tools and only dry natural sand without binder on top of the tools is removed by scanning. -12- The assembly being controlled and controlled by an automatic control system

  who knows by identifying each arm of the carousel the type of half

  mold having just been filled at the station c-types of half-molds which always succeed one another in the order lower half-mold-upper half-mold for the same mold-the order for deflating the stops is only given for an upper half-mold and the high or low position of the metal profile marked 8b is controlled by inductive proximity detectors marked 8k; the order of rotation of the carousel ensuring

  the transfer from post c to post d will be subject to - among other conditions -

  o1ns-check the correct position of the profile marked 8b according to

  type of half-mold concerned by this transfer.

  At the end of the transfer rotation, the sand leveled by the device identified 7 and swept by the device identified 8 if it is an upper half-mold falls by gravity largely into the hopper of the recycling device identified II and partly on the vibrating elevating table then in the low position; the part of sand fallen on the vibrating table is then expelled at the end of the transfer rotation in the hopper of the recycling device identified by the identified device 10 consisting of a set of brushes of the same type as those of the device marked 5, fixed under each of the 2 side members of each of the 4 positions of the carousel. During the filling-vibration operation of the next half-mold, the lifting table being rid of the sand before the start of the filling-vibration operation, this operation can be carried out without difficulty, which would not have been the case. if the sand partially fallen on

  the vibrating lifting table during the scraping or scraping operation-

  previous scan had stayed there.

  According to a preferred but nonlimiting embodiment, the rest of the recycling device identified 11 consists of an emitter of the "pneumatic dense phase transport" type which redirects the recovered sand to the filling hopper, by the driving force of the air. compressed, through a closed pipe; this arrangement is chosen in preference to other sand transfer systems to preserve the advantages of low noise and dust nuisance of the process and taking into account the nature of dry sand without binder who

  advantageously lends to this transport technology.

  The accompanying drawings in Figures 6, 7 and 8 show the cut-out-laying device for the closing plastic sheet, marked 6

as a whole, in more detail.

  FIG. 6 is a top view of the whole of the device 6, the sliding frame of which is marked 6a is in the fully extended position for

  removing the closing plastic sheet on the chassis of the half

  mold at the post, chassis marked CH.

  Figure 7 is a side view along section I-I of the device 6, and shows the enlarged detail of the types of profiles carrying sheets

marked 6b, 6c, 6d and 6th.

  FIG. 8 is a view in section II-II showing that the sliding frame marked 6a passes between the lateral parts of the device marked 5 when this device is in position for taking the chassis CH of the half-mold in position d; the arrows directed towards the reference x

  in the partial sectional view of the apparatus 5 in FIG. 8 corresponds

  tooth at the connection to the vacuum source; the device identified 5 is of the same type as that described in the patent application

n 7504686.

  According to a preferred but nonlimiting embodiment, the device 6 consists of a sliding frame marked 6a provided with

  its 2 ends of square tubes "leaf carriers" marked 6b and 6c.

  The frame 6a translates horizontally thanks to 4 bearing rollers marked 6f rolling on the horizontal parts of 2 U-shaped support profiles marked 6g; the 4 rollers marked 6f ensure the maintenance of the frame, even when the latter is in the extreme out position as shown in Figures 6 and 7,1 'support of the front rollers on the upper wings of the profiles marked 6g compensating for the overturning torque

  of the part of the frame outside the supports 6g.

  A pair of boxes with double balls marked 6n fixed on the lateral wings of the frame 6a ensure the lateral guidance of the frame, each ball bearing on the internal vertical walls of the profiles

support 6g.

  The frame 6a is driven in translation by 2 chains marked 6h each fixed by 2 quick couplings on a part secured to the lateral parts of the frame 6a; each of the 2 chains meshes with 2 toothed pinions, one motor the other ensuring the tension of chain; the 2 motor pinions marked 6i are supported by a pin marked 6k passing through Z bearings fixed on the top of the support profiles 6g; a motor with 2 directions of rotation

  marked 61 causes the axis 6k to rotate.

  At the other end of the support profiles marked 6g, an axis marked 6m passing through 2 bearings fixed on top of the profiles 6g carries the 2

  non-powered sprockets completing the chain mechanism for driving

  ment in translation in both directions of the frame marked 6a.

  -14- By convention compared to Figures 6 and 7, when the frame goes from right to left, the movement is an advance or exit and if the

  frame goes from left to right it is said to move backward or inward.

  2 "carrier" tubes marked 6d and 6e can go up or down together by a few centimeters thanks to their connection at the 2 ends by threaded rods marked 6q to plates marked 6o surmounting

  each an inflatable stop marked 6p.

  The principle of ascent-descent of these 2 carrying tubes 6d and 6e is identical to the system of inflatable stops ensuring the movements of ascent-descent of the profile marked 8b of the device 8: securing of the movements of ascent-descent of the plates 6o and the tubes 6d et6e

  by the threaded rods 6q; the threaded rods can slide through

  bore holes made in the support part 6r of each inflatable stop and sets of locknuts identified 6s and 6t respectively limit the low position and the high position of the carrier tubes 6d-6e. Strokes and extreme high and low positions are easily

  adjustable by displacement of sets of locknuts 6s and / or 6t.

  When the 2 support tubes 6d and 6e are in the high position, they come

  come into contact with either the unwound plastic film or the supporting tubes

  6b or 6c of the frame 6a depending on the stop position of the frame 6a.

  Between the 2 tubes 6d-6e is placed a heating-cutting wire marked f consisting of a fine wire of resistant alloy stretched between 2 insulating supports marked 6u fixed on the external lateral parts of the 2 support profiles 6g; the insulating supports 6u allow adjust the mechanical tension of the heating wire, its position in height, and receive the arrival on terminals of the electric cables supplying the heating wire; when in service, the heating wire is supplied with

  Security voltage 24V.

  The horizontal level of the heating wire f is adjusted so that it is

  located between the high and low positions of the 2 tubes 6d-6e.

  At the end of the profiles, reference 6g, axis side 6m of support for the

  non-motor gnons, a set of 2 metallic parts marked 6v each provided with 2 free rollers marked 6w allows the roll of plastic film supported by its axis marked 6x to be put in place; a tension bar marked 6y is fixed under the profiles 6g, near the 6v parts. Each of the 4 carrying tubes 6b, 6c, 6d, 6e is made up, as shown in detail C, of a tube of square or rectangular section, closed at the 2 -15- ends and drilled with a large number of small holes on its active face which is the bottom face for the tubes 6b and 6c and the top face for the tubes 6d and 6e; at the edge of the active faces are welded 2 bars

  square, just at the limit of a longitudinal row of holes.

  Each tube is connected individually and autonomously through rigid then flexible pipes, taking into account the movements that each tube can travel, to a motorized 3-way valve which can connect the interior volume of the tube either to the source of general vacuum or to / k pectivmet the atmosphere (3-way valve / motorized identifiedow. for the carrier 6b, identified 6cl for the carrier tube 6c, identified 6dl for the tube 6d and 6el

for tube 6e).

  When a roller end is applied to the active face of a carrier tube and the latter is connected to the vacuum network, the film, pressed by suction, is held by the carrier tube which, if it moves carries with it the thin plastic film; the role of the 2 bars is to considerably reinforce the peel resistance of the film

  of the active face of the carrier tube if the film is pulled perpendicularly

  in the direction of movement of the carrier tube.

  The cycle of the entire device 6 in automatic operation is

described below.

  When a new roller is placed on its supports 6v, the frame 6a is in the retracted position in the support profiles marked 6g so that the support tube 6c is slightly to the left of the tension bar 6y for a lateral view as in FIG. 7 the end of the roller is manually unwound a few centimeters, passing it over the tension bar marked 6y until it comes

* apply to the active face of the tube 6c; a signal given to the automa-

  tism by pressing a push button then puts the tube 6c in connection with the vacuum source; then a second press on the same button

  pushbutton controls the start of the cycle.

  The frame 6a advances by rotation of the motor 61 until the tube 6c, still connected to the source of vacuum, is perpendicular to the tube 6e,

  which ensures the unwinding of the film up to the vertical position of this tube.

  The different stop or slowdown positions of the frame 6a are identified by inductive proximity sensors fixed in an adjustable manner on one of the 2 support profiles 6g and which detect the passage of a metal pallet integral with the frame 6a (detectors and pallet not shown in the accompanying drawings); likewise the high or low (adjustable) positions of the 2 tubes 6d-6e are controlled by inductive proximity sensors -16 not shown but arranged so

  similar to the detectors marked 8k of the device marked 8.

  The 2 tubes 6d-6e which were at rest in the low position are then mounted by inflation with compressed air of the 2 stops 6p so that the active face of the tube 6e comes into contact and bears on the active face of the tube 6c; when the automation has controlled this support (high position of the tubes 6d6e), the tube 6e is connected to the vacuum network by its motorized valve 6el and simultaneously the tube 6c, by maneuvering its

  6cl valve is returned to the atmosphere.

  After the expiry of an adjustable time delay known as the "decompression" time delay intended to allow the vacuum in the tube 6c to be canceled completely, the inflatable stops 6p are purged of some compressed air and the 2 tubes 6d-6e come down again, the tube 6e always being linked to the vacuum source; this first phase therefore ensured the unwinding of the plastic film roll up to 6th and the maintenance of its end held by the tube 6th, this in order to avoid operators having to access the zone 6d-6e which is above the moving parts of the carousel, which is not the case with the tube 6c at the start of the cycle and

6v roller supports.

  The replacement of a finished roller and the replacement of a new roller can therefore be done without intervention in dangerous areas, therefore without stopping any automatic cycle of the other equipment. The frame 6a moves back until the tube 6b is perpendicular to the tube 6e; the 2 tubes 6d-6e go up and when they are in the high maintained position, the upper active face of the tube 6e is supported on the active face of the tube 6b; the tube 6b is then connected to the vacuum source while the tube 6e is placed in the atmosphere; after expiration of the "decompression" delay, the 2 tubes 6d-6e are lowered the tube 6b being always connected to the source of depression which ensures

  the recovery of the terminal part of the roller.

  The frame 6a then advances, causing the unwinding of the roll, until the distance between the tube 6a and the heating wire f represents the

  sheet length required to cover the frame of the half-mold.

  (the cutting length is slightly greater than the internal dimension

  frame in position d which is perpendicular to the direction of translation of the frame 6a, the width of the roller being slightly

  greater than the other internal dimension of the chassis).

  -17- The frame 6a is then stopped, the tube 6b still connected to the source

  of depression, the 2 tubes 6d-6e go up together by inflation of the bu-

  when the 2 tubes are in the high maintained position they are so-

  simultaneously connected to the vacuum source by the action of their 2 motorized valves 6dl and 6el, which presses and tightens the part of plastic film between the 2 tubes; the heating wire f is then energized, then after a so-called time delay "preheating" corresponding to a sufficient temperature rise of the wire, the 2 stops are deflated, the wire being always under tension and the tubes 6d-6e

connected to the vacuum network.

  During the downward movement of the tubes 6d-6e, the stretched film of thin plastic comes into contact with the heated wire which ensures the cutting by fusion; when the 2 tubes 6d-6e have arrived in the low position,

  the power supply to the heating wire is interrupted.

  There is then a plastic sheet held between the tubes 6b-6d still connected to the vacuum source, the new end of the roller being held by the tube 6e still connected to the vacuum source. When the half-mold is in position d with the device marked 5 in position for picking up the half-mold, a signal is sent by the automatic control device 5 to the automatic control device 6; the tube 6d is then returned to the atmosphere, the tube 6b

  remaining connected to the vacuum source; after expiration of the time

  sation of "decompression", the frame 6a advances to its extreme exit position corresponding to the tube 6b to the aptmb of the lateral part of the most distant chassis (= the leftmost in the figure n'71, which ensures by sliding on the half-mold the installation of

  the closing plastic film sheet.

  As soon as the frame 6a has arrived in this position, the tube 6b is

  returned to the atmosphere and a signal is sent simultaneously to the automa-

  management -ism of the device identified 5 which then puts by its sockets

  of vacuum the chassis of the half-mold in connection with the vacuum network.

  The closing plastic sheet, as soon as it is released by the tube 6b, is thus pressed onto the top of the half-mold by the effect of atmospheric pressure; after the expiration of the "decompression" delay, the frame 6a moves back to that the tube 6b is perpendicular to the tube 6e, which completely releases the frame 6a from the vertical trajectory

  rising of the chassis and the device identified 5 during demolding.

  -18- If the vacuum level in the chassis, controlled by a vacuum switch on the vacuum circuit of the device marked 5, between its vacuum sockets and its motorized valve for connection with the vacuum source, is then sufficient, the demoulding of the half-mold by the device identified 5 can be carried out. The cycle of the device identified 6 is frozen until the half-mold and the device 5 have left the zone of the station d, which is informed to the automatic management of the device 6 by the management automation

5.

  At this stage, the device identified 6 is in the state corresponding to that after fitting and unrolling the new roller up to the tube 6e; as soon as the frame 6a can again come out without risk of striking the identified device 5 or the half-mold it carries, the cycle can start again. A photoelectric detector (not shown in the appended figures) placed near the tension bar 6y constantly monitors the smooth running of the roll and its presence and therefore detects the end of the roll; when the detector no longer sees the film, the device returns automatically to the starting position and an indicator light signals the end of the ripple or the possible rupture of the film to allow operators to restart the cycle after changing the roll or repairing the torn film. The device marked 5, after complete demolding of the half-mold, transports it by translation beyond the carousel; if it is a lower half-mold, the carriage marked 19 is then in the position shown on the

  figure n l and the device identified 5, after turning 180 of the half

  mold, deposit this lower half-mold on the free elevating table of the carriage 19; the carriage 19 puts its lower vacuum connection in connection with the half-mold before the device identified 5 disconnects its vacuum connections; when the apparatus 5 has removed its vacuum sockets, it leaves the lower half-mold on the carriage 19, connected to the vacuum source

by the vacuum outlet of the carriage 19.

  As soon as the device 5 is outside the translation path of the carriage 19, the gates p3 located on the path of the carriage 19 open and the carriage 19 advances to a position beyond the gates. The p3 gates then close, the p3 gate located laterally to the trajectory of the carriage 19 facing this second stop position of the carriage 19 /! O oqeautorise access for finishing work (installation of the cores, recovery of removable parts of undercut model, -19- etc ...) to the lower half-mold on carriage 19 but not access to

  carousel or to the work area of the identified device 5.

  When the operators have finished their work on this half-mold, they withdraw beyond the side door p3 and inform the automatic management of the carriage 19 and the doors p3 which then closes the side door p3.At the next quarter turn of the carousel, the half-mold demolded by the device identified 5 is then an upper half-mold; after complete demoulding, the device 5 transports this half-mold beyond the carousel, directly above the initial position of the carriage 19 , then rotates it by approximately 90 'and lowers it to working height, then stops all its movements while keeping the half-mold connected to the vacuum network. All of the p3 gates then open, which allows operators to access the upper half-mold without, however, being able to enter the carousel area, which can therefore continue its automatic cycle; when the work on the 2 half-molds is finished (lower half-mold on the carriage 19 in the stopped position facing the side door p3, work on the upper half-mold held by the apparatus 5 and of which the part on the impression side and the part on the top side are accessible for the cutting operations of the closing plastic sheet, for recovering the recoverable tools used to make the parts of the impression which must open) the operators withdraw beyond the side door p3 and inform the automation

Management.

  The side door p3 closes, then the device identified 5 raises the upper half-mold while making it rotate 90 'in the opposite direction to return it to the horizontal; the carriage 19 then returns to its initial position and the rewinding of the upper half-mold on the lower half-mold on the table of the carriage 19 is carried out by the apparatus marked 5, this removing its vacuum connections only when the carriage 19 has connected its upper vacuum connection to the upper half-mold. The apparatus 5 then leaves the trajectory zone of the carriage 19 to continue its cycle, then the carriage 19, carrying the complete mold kept connected to the vacuum network, returns to its stop position facing the side door p3; the doors p3 on the trajectory of the carriage 19 then closes while the side door p3 opens: the operators can then safely access the mold on the

  carriage 19 for finishes such as for example cramping of the 2 half

  molds without being able to enter the working area of the carousel and the device 5 which can therefore continue their automatic cycles without problems. When the operators have completed these works, they withdraw 20- beyond the side door p3 and inform the automatic control system which closes this gate then sends the carriage 19 to one of

its drop positions.

  This set of devices therefore makes it possible to produce a mold for flat casting with a minimum of limited manual intervention.

  to tcut which is not repetitive and constant and this with a production-

  maximum activity since these interventions occur outside the molding and / or working area of the device identified 5 for transporting the chassis and half-molds, therefore do not stop the automatic cycles of these

appliances.

-21-

Claims (1)

CLAIMS - Set of devices allowing the realization, in an automatic system, of molds for flat casting using dry sand without binder, characterized in that they comprise: - a device for scraping sand leveling eliminating the excess sand above of the upper edge of the chassis; that this scraping device uses the movement of transfer of the chassis between 2 operating stations to carry out the removal of excess sand by means of a sheet metal whose leading edge covers the entire section of the chassis during the transfer, device marked 7 as a whole in FIG. 1. a scanning device, posterior to the scraping device and acting only for the top of an upper half-mold; that this scanning device can be put into service or retracted by an up-down movement obtained by inflatable stops; that this device ensures the removal of the sand above the tooling or impression parts in front of the outlet expensive by using the movement of transfer of the chassis between 2 operating stations and this before the automatic installation of the sheet of closing plastic film; that this device thus allows the subsequent easy cutting of the parts of the sheet of closing plastic film corresponding to the parts emerging from the mold, device marked 8 as a whole in FIG. -a device for unwinding-cutting-laying the closing plastic sheet carrying out the automatic laying of the sheet on the half-mold after the scraping and / or sweeping operations thanks to a carrying tube situated at the end of a sliding frame which can pass through the arms of a demoulding device-transport of half-molds or chassis when this device is in the demolding position; that the replacement of the plastic film roll feeding this device is done outside the carousel's working area or the demoulding-transporting device therefore without stopping the automatic cycles thereof, device generally identified 6 in Figures 1 and 2. -a device for cleaning excess sand removed by the scraping and sweeping devices having been able to redeposit on the vibrating lifting table; that this cleaning device made up of a set of brushes fixed under each of the beams supporting the box of the transfer carousel u uses the transfer movement to clean the vibrating elevating table; device marked 10 as a whole in FIG. 2. -22- -a device for recovering excess sand and recycling in the filling hopper characterized by a section hopper upper dimensioned according to the positions of the scraping, sweeping and cleaning devices, overcoming a dense phase pneumatic transport transmitter in order to keep the process its low nuisance and noise and in dust; device marked 11 as a whole in FIG. 2. - a device composed of fixed barriers, a transfer trolley provided with 2 vacuum sockets, a set of gates allowing safe access to the lower half-mold and / or to the complete mold on the trolley stopped outside the molding, on both surfaces of the upper half-mold - cavity side and mold top side for finishing work outside the molding area; devices marked respectively 18, 19 and p3 in figure nl.   2-devices according to claim 1 characterized in that: the inclined shape of the scraper plate of the scraper device in action prevents any lifting by the sand and that the shaped parts attached to the parts connecting the sheet to the axes pivoting avoid any catching by the chassis during the transfer;   sheet marked 7e and shaped parts marked 7d in FIGS. 3 and 4.   -the sweeping device has an easily adjustable level to compensate for the wear of the brush linings thanks to a set of nuts   and adjustable locknuts on the threaded rods connecting the pro-   spun brush holder with the up-down system activated by the inflatable stops; that the brushes can be replaced very quickly   without any tools thanks to an eccentric cam locking device   secured to a lever at the 2 ends of the row of brushes; set of locknuts marked 8i and 8j and threaded rods marked 8g in figures n'4 and 5; locking devices marked 8c in the Figures 3,4 and 5.   -the device for depositing the closing plastic sheet comprises a heating wire (marked f in FIGS. 6 and 7) allowing the sheet to be cut to length completely automatically and a detector for monitoring the end of the roll or of breakage film 3 or roll unwinding incident; that the frame (marked 6a in figures n'6 and 7) of the device does not hinder, in the retracted position, the mold release movements of the chassis, which allows the device to be used transfer of half-molds to create the depression in the half-mold -23- without having to make a connection of the chassis with the source of depression   by another device when removing the plastic film sheet.