DE2313183A1 - Mould closure load transmitted by compensator - to equalise pull on all rods and simplify adjustments - Google Patents

Abstract

A mould closure mechanism for casting moulds, injection moulds, etc., comprises tension rods anchored at one end to one component (e.g. fixed mould plate) and connected at the other end by a driving mechanism to another movable component (e.g. movable mould plate); when the driving mechanism is operated, it pulls the two mould plates together. One mould plate is slidably mounted and guided on tension rods; the tensile force is transmitted from each rod to this plate through a liquid-filled chamber (piston-cylinder principle); all the chambers of all the rods are interconnected so that the pressures in all the chambers are in equilibrium.

Description

Device for use in die casting, injection molding or the like. like.

The invention relates to a device for use leg Druckcfienten, injection molding od. The like., With softer on a bed a first and a second component is arranged so that it can move relative to one another and away from one another as well as several elongated pulling elements are in front of them is connected at one of its ends to the first component, wherein an actuating device connected to the other end of the tension elements and also with component darart is that by actuating one of the outer components can be pressed against the other, so uaß, uas first and second component by starting the actuator are exposed to compressive stress, the tensile elements are subjected to elongation are subject.

The first and second components are thus in operation between a first and second position moved relative to each other, wherein in in the first position the components or corresponding components carried by them are in the closed position, while the components are in the second position or organs carried by these are arranged at a distance from one another. The actuator causes such relative movement of the components and a contact pressure between the components or the organs supported by them, if they are in the first Position are located, the zugelemente extend parallel to the direction of this relative movement of the components and are arranged so that they collectively the result the activity of the actuating device to absorb the forces generated for cause the contact pressure are required, with the tension elements a Be subjected to tensile stress.

i The invention was primarily designed for die casting devices, the particular problems of which are to be explained in detail below The task of finding is to overcome or to advance. It is understandable, however, that the Lrfindung also on other embodiments of devices such. ii. at Injection molding machines is applicable, in which similar or analogous problems occur.

In the case of die casting devices, it is customary to provide two mold carriers (which are the aforementioned first and second components), one of these mold carriers on the machine bed stationary and the other on the latter are movable ar brought, una the movable component by the actuating device is movable in the direction of the fixed component and away from it. If that the moving component is moved in the direction of the stationary component Molded parts carried by the two components on the partial or separating surfaces of the molded part in mutual contact and are controlled by the actuating device held in a closed position showing the mold cavity Are defined. The actuator usually consists of a mechanism with which a extremely high closing force can be generated through which the molded parts in mutual be held in touch, e.g. b from a toggle mechanism in which the toggle arms are in a straight or approximately straight position when the Mold carriers are in the first position mentioned above.

To ensure that the stop surfaces of the molded parts are exactly parallel stay to each other, it is common to have several tension elements, usually in the form of Rods that are connected in positions to the fixed mold carrier are, which are provided on the same at a distance from one another over the Un.-catch, wherein the pull rods are also connected to a carrier, aer the actuating device or parts of it.

In the ideal state, these tie rods were evenly stressed, and when the mold carriers are moved to their first position, the stress decreases a certain Bert that is sufficient to prevent metal from leaking out of the mold cavity between the surfaces of the molded parts abutting one another in the parting line decrease, whereby this particular value is below de @ yehigen, the one excessive Wear or damage to the actuator. or other parts caused by the device.

After a certain operating time, the temperature of the molded parts rises at. The dimensions that the molded parts between the movable and fixed Occupy mold carriers, increase and exceed in terms of thermal expansion those of the tie rods. As a result, the learning or closing pressure between the stop surfaces of the molded parts rises above the appropriate value. Furthermore, the tie rods can cause uneven forces with respect to one another different heating or other reasons.

considerable time and experience was required for the recruitment of the expansion bolts on the tie rods are required to ensure that each Drawbar is loaded equally as far as possible.

The invention is characterized in that at least one of the first and second components slidably arranged on the tension elements and as a result is guided through this, with a corresponding one in connection with each of the tension elements Chamber is provided which, when the device is in operation, with liquid is filled, each chamber in the force path to one or through a corresponding one The tension element is connected to Ulld relatively movable walls for the transmission of the force through the liquid, and that all chambers are connected by lines are connected so that the fluid pressures in question in the chambers can be compensated are.

With this construction a certain relationship is established with regard to the stress of each Zegelemtnes maintained. For example, if the tension elements are formed in Foni by rods, which among themselves have the same cross-section have, and the corresponding chambers associated with the tie rods are the same Have construction, an equal stress on all tension elements is maintained.

Preferably, all of the chambers are connected to a pressure direction.

The pressure relief device works so that they an excessive Contact or closing pressure between or from the first and second components worn parts as well as excessive stress on the tension elements or components the actuator prevented.

The pressure relief device can either operate so that it a stress on the tension elements beyond a certain maximum inert prevented or the size of the increase in stress in the tension elements in comparison decreased to those increase that bein. Absence of the pressure relief device So the pressure relief device can occur from a pressure relief valve best to limit the pressure that can be in the foreland in the chambers. Additionally or alternatively, the pressure relief device can consist of a. Storage containers exist, in which at least the upper part is a gaseous, pressurized liquid contains, the chambers are filled with liquid and the arrangement is made is that the liquid from the chambers in a lower part of the storage container can be displaced.

The invention is illustrated by way of example in the drawings.

1 shows a diagrammatic representation of a die-casting device nacil of the invention, the mold carriers being shown in the second position, Fig. FIG. 2 is an end view of a die casting apparatus in the direction of arrow A in FIG. 1 and in comparison with FIG. 1 on an enlarged scale, FIG. 3 is a broken away view in the direction of arrow b in FIGS. 2 and 4, a broken away view in FIG larger scale showing in cross section one of the chambers of FIGS. 2 and 3 together shows with a tension element associated with the chamber.

The apparatus of Figure 1 consists of a generally ciit the reference number 10 provided bed on which a towering Fern carrier in shape a plate 11 is attached which is stationary with respect to the bed. Another Mold carrier, also in Lorn.

a plate 12, is on the 'L: ett opposite the plate 11 in and arranged to be displaceable, the plate 12 having a sliding part for this purpose 13 is provided, which is effective in a guide track 14 on the bed 10.

The mold parts carried by the mold support plates 11 and 12, respectively are shown in outline at 15 and 16.

On the side facing away from the fixed mold carrier plate 11 movable mold support plate 12 is an actuator generally designated 17 intended. This includes a pressure fluid piston 18, which is hydraulic or can be operated pneumatically, as well as a toggle mechanism 19 through which the Piston rod of the piston with the movable mold carrier plate 12 in the direction of actuation connected is.

For this purpose, the toggle mechanism ordered from an upper and lower pair of toggle arms 20 and 21 shown diagrammatically, the Toggle arm pairs are connected by a compensation lever 22, which in turn with the Piston rod 23 of piston 18 is connected.

The thumb arms 20 and 21 are on the outside with bearing blocks 24 and 25, respectively movable mold carrier plate 12 and on a also designed as a plate 26 Support pivotally connected, the latter being slidably attached to aun der.i bed and is stranded with an opening through which the piston rod 23 of the piston is passed is.

The carrier 26 is through with the stationary mold carrier plate 11 several tension elements connected in cestalt by rods 27, which extend through openings extend in the movable mold support plate 12 and its second function therein exists to guide them and to maintain the parallel position of the mold carrier plates 11 and 12 contribute to each other.

The tie rods 27 are built on their left as shown in FIG. 1 Itit screw-threaded thrust bearings. which through openings in the fixed Go through the mold carrier plate 11, where in this thrust bearing fastening nuts 28 wear that are tightened so that the plate 11 is attached to the shoulder at the junction of the thrust bearing and on the main part of the tie rod in any case.

At the other end, each tie rod 27 has a screw thread part 31 provided, on which a stop nut 29 is screwed, which is on the left Side of the carrier 26 is applied. Another stop nut 30 is on the; Screw thread part each tie rod is arranged on the right side of the carrier 26. Between everyone this stop @ uttern 30 and a right side of a carrier 26 is a linear unit 32 is provided which contains an annular chamber with walls that are relative to each other are movable such that the volume of the chamber can be changed.

One of the units 32 is shown in detail in FIG. 4, from which It can be seen that the unit consists of an inner part 33 with a screw thread part 31 of the associated pull rod tightly ur.scillic-Benden sleeve part 34 and one with this formed as a whole, radially extending and generally cylindrical Flange 35 best. The line 32 further comprises an outer part 36 with an inner part 37, which tightly overlaps the outer peripheral surface of the flange 35, and furthermore one extending radially inward Flange part 38, which is tight over the sleeve part 34 is located.

An annular chamber 39 is defined by the inner and outer parts 33 and 36, respectively created, with an axial wall and the radial inner limit of the chamber are formed by surfaces of the inner part, and the other axial wall and the radial outer boundary of surfaces of the outer part are formed. The interior and exterior parts. can be displaced relative to one another in the axial direction, so that the volume the chamber 39 is changed.

The outer part 36 is attached to a ring 40 by means of screws, which in turn is attached to the carrier 26. It is explained in more detail below, that when the device is in operation, the ring 40, 40 is subjected to a compressive load and that therefore the connecting the ring to the carrier 26 and the outer part 36 Screws are not exposed to the force that wear through the tension element 27 over will.

A retaining ring 41 is screwed onto that end face of the outer part 36, which is turned away from the carrier 26. This retaining ring is superimposed on a radial outer one Part of the associated end face of the inner part 33. Pin 42, which is fastened in the inner part extend with a sliding fit through breaks in the lialtering are provided so that relative rotation of the inner and outer parts is prevented while a relative sliding movement is possible in the axial direction.

The radially inwardly directed surfaces of both the sleeve part 37 as well as the flange part 38 of the outer part have annular expansions, within which corresponding sealing rings 43 and 44 are arranged. These sealing rings call for a leakproof seal between the inner and outer parts both lands of the Kaiiner 39, while at the same time a relative thrust motion the interior and exterior parts is possible.

Two connection openings 45, each provided with a nut thread are arranged in the outer part 36, with corresponding lines 46 extending from these connection openings to the chamber 39 extend. As Figs. 2 and 3 show, are the units 32 interconnected by pipes 47, which are not shown with End fittings which are screwed into the connection openings 45 are versenen.

In this way, all of the chambers 39 are either direct with one another connected via one of the tubes 47 or indirectly via a further chamber 39.

The chambers 39 are also via a further pipe 48 and an A »control valve 49 connected to a pressure relief device.

The printing load device consists of one. Storage container 50, which can be designed as a cylinder, which is arranged vertically and on one side of aes carrier 26 is attached. A line 51 connects the lower end of the storage container with the A shut-off valve 49. At the upper end is the storage container connected to a pressure indicator 52 and a pressure relief valve 53.

When the device is in operation, the chambers 39, the pipes 47 and 48 and a lower part of the reservoir 50 with a hydraulic fluid filled, e.g. one: oil commonly used in hydraulic devices. An upper part of the reservoir is filled with an inert gas, which is below a pressure indicated by the pressure indicator 52 is maintained.

The inert gas can be released into the reservoir through the pressure relief valve 53 from a suitable pressurized source. If the Pressure inside the storage container 50 reaches a certain maximum value, opens uas valve 53, so that a certain amount of the inert gas is discharged and is prevented in a targeted manner that the pressure inside the reservoir exceeds the certain ntaxinal reads. hydraulic fluid can be fed into the device via a inlet valve 54, which is connected to the pipe 48 connected is:.

A vent valve 55 is suitably connected to one of the tubes 47 for venting air from the chambers 39 and the tubes 47 connected when these first be filled with hydraulic fluid, as well as for any later Ventilation processes, ie during the operating time of the device, are necessary.

When the device is in operation, the mold parts close 15 and 16 by the actuating device 17 to one; certain pressure between the stop surfaces of the molded parts in the parting plane. Simultaneously with this is each pull rod 27 is subjected to stretching because the molded part 15 is affected by the Form part 16 exerted force on the plate 11 and then on the nuts 28 the tie rods 27, on the nuts 30, on the units 32, as well as on the carrier 26 on the @ fog mechanism 19+ The units 32, the carrier 26 and the toggle arms 20 and 21 of the toggle mechanism are each subjected to compressive forces.

A decrease or decrease in the volume of the chamber 39 is carried by the liquid inside the chambers on their axial walls Prevents applied pressure when the units 32 are subjected to compressive stress will. The expansion in the tie rods 27 is therefore caused by the fluid pressure determined within the 'associated chambers 39. Since the tie rods 27 and the Units 32 are each designed in the same way and the pressure in all chambers 39 is the same, the tie rods are subjected to the same stress. Further the elongation stress on each tie rod is limited due to the fact that the pressure in the associated chamber 39 does not exceed a certain maximum inert can go out, which acts on the opening pressure of the pressure relief valve + 53 is equivalent to.

The valve 53 can be provided with means for adjusting the pressure be in which the valve opens to vent gas from the reservoir 50, so that an operator can select or set the maximum elongation, which the tie rods 27 can be subjected.

During a period of operation of the device, it is melted Metal by means diagrammed at 56 in Figure 1 through conduit injected through, which extends through uie fixed mold carrier plate 11 extends into the mold cavity which is formed by the mold parts 15 and 16, when these are in their closed position. Correspondence will be the mold parts 15 and 16 and to a certain extent also the plates 11 and Heat and expand 12. Although the tie rods 27 are also up to a certain point Outlet can be heated, their temperature rises far less in general than is the case in the molded parts. Appropriately name the dimensions, which the molded parts together between the fixed and movable plates 11 and 12, with respect to the length of the tie rods.

the excessive increase in contact or closing pressure between the mold parts 15 and 16, the other hand from the relative Lxpansion of the mold parts relative to the shape carriers is avoided by the line guides 32. if the expansion of the tie rods 27 increases, the inner part of the associated Unit 32 in the axial direction relative to the outer part, so that aie total length of the ineit 32 is reduced. Accordingly, a certain part of the hydraulic Fluid is drained from chamber 39 through tubes 47 and 48 to reservoir 50. Such a movement of the hydraulic fluid in the Vorratsbehä.lter calls a crack compression of the inert gas in the upper part of the same and and a corresponding increase in pressure in both the gas and the liquid. during normal operation, however, is the volume of liquid that is removed from the Chambers 39 emerges, relatively small, and the Druckzunahne is not so great that there is damage or a noticeable increase in wear the components of the device is caused.

It is understandable if the mold parts 15 and 16 ate during ucs Operation of the device are open, the delmung in the tie rods 27 to a certain extent Extent decreases and accordingly each chamber 39 can expand, hydraulic Liquid is withdrawn from the reservoir 50.

A visual display of the relative positions of the inner and outer parts 33 and 36 of that unit 32 is caused by the length of the pin 42, which extend beyond the retaining ring 41.

The relative positions of the inner and outer parts shown in FIG. 4 corresponds to the lowest strain in the screw thread part 31 of the associated pull rod. Such a slightest stretch is caused by the setting the stop nuts 29 with respect to the stop nuts 30 causes. Preferably the nuts are so einsteyllt relative to each other that the expansion in the screw thread part of the tie rod is equal to the maximum elongation that the tie rod can experience during a initial work cycle of the device is caused, e.g. fl. before the moldings have warmed up. If the device is set in this way, will the pressure inside the chamber 39 during the initial working cycle of the Do not change the device, but to some extent during later work periods increase when the mold parts 15 and 16 are exposed to the closing pressure.

Although in the preferred embodiment shown in the drawings the chambers are filled with hydraulic fluid be, can these chambers are also filled with pressurized gas, in which case the reservoir can be omitted. Since a gaseous liquid is compressible, a some degree of pressure relief and there would be a pressure relief valve be provided to limit the maximum pressure that prevail in the chambers can.

In a further modified arrangement, the chambers could be hydraulic Contain liquid, the pressure relief device being an elastic element, which is in a solid aggregate state, could represent the sicii accordingly, it can bend unci so a limited increase in the absorption of the liquid provided space. Such an elastic element would preferably arranged in a storage container connected to the chambers, but it it can be seen that aas elastic element can be arranged within the chambers oaer can form a wall of these chambers. A uniform stretching load would be maintained in gene tie rods because the chambers are between each other would be connected.

It can be seen that when the units 32 are interconnected, but would not be connected to a pressure relief device, the device nonetheless has the advantage over conventional device of the type described that the Tension elements are evenly loaded. An equal strain of the Tie rods ensure the same or essentially the same stretching of the two pairs of toggle arms 20 and 21 and also avoids a deviation from the also parallel relationship between the mold parts 15 and 16 resulting from an unequal Stretching stress on the tie rods could result.

Claims (7)

P a t e n t a n s p r ü c h e 1) Device for use in die casting, injection molding or. agl., in which a first and a second sound part on a bed against each other and away from each other relatively movable and several arranged length extending tension elements are provided, each of which at one of its Linden is connected to the first component, with an actuating device the other end of the tension elements and also connected to the second component in this way is that by means of the actuator one of the components against the other is compressible, so that when the first and second components by starting the actuator are exposed to compressive stress, the tensile elements are subjected to elongation are subject to the fact that at least one the first and second components (11, 12) are arranged displaceably on the tension elements (27) and is consequently guided through it, wherein in connection with each: the tension elements a corresponding chamber (39) is provided which, when the device is in drive is, is filled with liquid, with jeae hanser in the power path to a or is geschcilalten by a corresponding tension element and relatively movable walls to transmit the force uurcn the liquid, and that all chambers are interconnected by lines (47), so that the respective fluid pressures can be compensated in the chambers. 2) .Vorrichtung according to claim 1, characterized in that a pressure relief device is provided in connection with the chambers (39). 3) Device according to claim 2, characterized in that the chambers (39) filled with liquid sinu and the pressure relief device from one There is a reservoir (50), the upper part of which contains gaseous pressure fluid and the lower part of which is connected to the lines (47) of the chambers (39), the upper and lower parts of the storage container communicating with one another. 4) Device according to claim 1, characterized in that the zetichtungvorrichtung consists of a carrier (26) through which the tension elements (27) extend, and from a toggle mechanism (18) between the carrier (26) and the second component (12) is connected, and that the chambers (39) between the carrier and corresponding Stop members (29, 30) are arranged on the tension elements (27). 5) Device according to claim 2, characterized in that the chambers (39) are filled with liquid and that the pressure relief device consists of a resilient element in the solid aggregate state, which is a can cause limited enlargement of space for the liquid. 6) Device according to one of claims 2 to 5, characterized in that that the pressure relief device from a pressure relief valve (53) to limit of the pressure in front of the chambers (39). 7) Device according to claim 6, characterized in that the pressure relief valve (53) in the sense of a change in the maximum pressure present in the chambers (39) is adjustable. L e r s e i t e