Sand casting tool and method for the installation thereof

Abstract

1. Method for installing a sand casting tool and appropriate casting tool. 2.1. The invention relates to a method for installing a sand casting tool comprising at least one mold element (10) having a mold recess (14a) which at least partially defines the contour of a sand casting to be produced, at least one leveling rod holding device (40) which is displaceable in the direction of a Z-axis relative to said mold element (10) and which is disposed on the side of the mold element (10) facing away from said mold recess (14a), at least one leveling rod (30) capable of being inserted through an access bore (20) in said mold element from the outside surface of said mold element (10) as far as said mold recess (14a) and which can be attached in a fixed position to said leveling rod holding device (40). 2.2. The invention includes the following steps: A. insertion of the leveling rod (30) in the direction (2) of the Z-axis into the access bore (20) of said mold element (10), and B. attachment of said leveling rod (30) to said leveling rod holding device (40). 2.3. The use thereof, particularly for achieving high precision of position and alignment of the leveling rods relative to the leveling plate. 3. FIG. 2a.

Description

TECHNICAL FIELD AND PRIOR ART

The invention relates to a method for installing a sand casting tool, which generic sand casting tool has at least one mold element having a mold recess that at least partially defines the contour of a sand casting to be produced. A generic sand casting tool further comprises at least one leveler holding device, which is displaceable in the direction of a Z-axis relative to the mold element and which is disposed on the side of the mold element facing away from the mold recess. At least one leveling rod is assigned to the leveling rod holding device, which rod is insertable through an access bore in the mold element as far as the mold recess and can be firmly attached to the leveler holding device. The invention further relates to a corresponding sand casting tool.

The sand casting tools to which the present invention relates are used for making components out of sand, wherein these components made of sand are mostly sand cores which are used in subsequent casting procedures involving other tools to keep cavities in a casting free from casting compound. These sand castings are generally produced using a sand casting tool comprising a mold cavity, which is generally jointly formed by two mold elements. Sand acting as casting compound is shot into this mold cavity. Any sand still remaining in the corresponding bores of the mold element after the shooting process is then pressed into the mold recess by leveling rods, and the usually flat end face of the leveling rod ensures that the sand casting being produced also has a defect-free surface in the vicinity of the shooting bores. The leveling rod initially remains in a position in which its end face is flush with the mold recess. In this position the shot sand is gas treated in that gas is fed into the mold recess through an annular gap between the leveler and the shooting bores, which gas causes the sand particles to bond with each other, thus forming the desired dimensionally stable sand casting. The latter can then be removed from the mold recess.

A problem arises with the sand casting tools known in the prior art due to the fact that, as a general rule, a plurality of shooting bores and a plurality of leveling rods are provided. These leveling rods are mounted on a common leveling rod holding device and are positioned according to the positions of the shooting bores in the mold element. However, it is frequently not possible to maintain the alignment of the leveling rods relative to the leveling rod holding device with sufficient precision, which may result in damage to the shooting bores and/or to the leveling rods when there is movement of the leveling rods inside the shooting hole. This problem arises in particular because the annular gap used for gas treatment may have only a small width such that only a narrow clearance is present between the leveling rod and the shooting hole, particularly in the vicinity of the contour of the mold recess. Furthermore, the problem of damaging the shooting bores or the leveling rods arises, in particular, due to the fact that for each sand casting being produced with standard prior art devices, it is necessary to exchange the leveling rod holding device holding the leveling rods with a nozzle plate for shooting in the sand, which then always requires subsequent reintroduction of all of the leveling rods into the corresponding shooting bores. The fact that the leveling rods are continually withdrawn from, and then reinserted into, the shooting bores soon leads to damage.

OBJECT AND ITS ACHIEVEMENT

It is an object of the invention to provide an installation method by means of which a sand casting tool can be installed in such a way as to minimize damage to the leveling rods and/or the access bores during operation. A further object of the invention is the provision of a suitable sand casting tool that is especially well-suited for carrying out the said method.

According to the invention, the method for installing the generic sand casting tool described above comprises two method steps, wherein, in a first method step A, the leveling rod is inserted in the direction of the Z-axis into the access bore in the mold element and, in a subsequent method step B, the leveling rod is attached to the leveling rod holding device.

The novelty of the method resides in the fact that the attachment of the leveling rod to the leveling rod holding device does not take place on the basis of prespecifications concerning the position of the access bore, but instead the leveling rod is first inserted into the access bore and is thereby aligned correctly. The attachment of the leveling rod to the leveling rod holding device only takes place subsequently, thereby ensuring that the leveling rod holding device is also correctly positioned and aligned in the assembled state. For the purpose of this invention, the expression “leveling rod holding device” is to be understood to mean the unit by means of which the force is transferred to the leveling rod during operation thereof.

Preferably, the method is intended for the installation of a plurality of leveling rods, mounted on a common leveling rod holding device. With this method several, preferably all, of the leveling rods are initially inserted, in method step A, into the corresponding access bores and are attached to the leveling rod holding device in a subsequent step. The use of a plurality of leveling rods makes the installation method of the invention advantageous, as doing so eliminates the otherwise existing danger of the leveling rods being attached to the leveling rod holding device in mutually differing directions deviating slightly from their target position, with the consequent particularly strong risk of damaging the access bores and/or the leveling rods. When inserted in the access bores, the leveling rods are optimally aligned, not only in terms of their position but also in terms of their longitudinal direction, thus ensuring that, with the use of a plurality of leveling rods, the latter are aligned parallel to each other.

It is preferred that the leveling rod be aligned relative to the mold element when inserted in method step A, the freedom of movement of the leveling rod relative to the mold element being restricted such that the leveling rod is translatively displaceable by not more than 0.5 mm in the direction of an X-axis and in the direction of a Y-axis, which axes are aligned orthogonally relative to each other and to the Z-axis, and such that the leveling rod is rotatably tiltable about the X-axis and about the Y-axis by not more than 3° in each case.

These values have proven to be suitable for ensuring a sufficiently precise attachment of the leveling rod or the leveling rods to the leveling rod holding device. However, it is considered to be advantageous in this regard if the maximum degree of translative movement is restricted to 0.3 mm, preferably 0.2 mm. Preference is given to a maximum tiltability of the leveling rod about the X-axis and the Y-axis respectively of 2°, with particular preference being given to a maximum of 1°.

The alignment imparted to the leveling rod by the access bore can be ensured by adapting the shapes of the leveling rod and the access bore to each other so that the aforesaid alignment ensues.

As an alternative improvement, however, provision can be made for the insertion of an alignment insert together with the leveling rod into the access bore in method step A, in which case the alignment insert, by contacting a wall of the access bore on the one hand and the leveling rod on the other, ensures the aforesaid restriction of the freedom of movement of the leveling rod relative to the mold element in the inserted condition.

The alignment insert is an element so configured on the one hand that it assumes a specific position in the access bore relative to the X-axis and the Y-axis and so configured on the other hand that it is capable of keeping the leveling rod in a specific position relative to the X-axis and the Y-axis. The alignment insert can be provided as a separate element, which is inserted into the access bore only for installation purposes. However, it is also possible to use an alignment insert that remains permanently attached to the leveling rod, for example by shrink fitting. The use of a separate alignment insert offers the advantage that the latter can be configured so that, in conjunction with the leveling rod, it closes the access bore completely. Although this is not detrimental to the installation procedure, it prevents any subsequent gas treatment during actual casting phase. Alignment inserts configured such that they which would completely close the access bore in an operational position of the leveling rod, must be removed after the installation step.

In an improvement of the invention, the leveling rod is inserted, in method step A, into the access bore such that it protrudes into the mold cavity. The leveling rod is accordingly displaced in the direction of the Z-axis into a position which is at least 2 mm to 3 mm deeper in the access bore than the position of the leveling rod during subsequent gas treatment of the sand casting being manufactured. This deep insertion of the leveling rod in method step A makes it possible to achieve the desired alignment of the leveling rod by contact between the access bore and the leveling rod, by means of which the access bore is completely closed. While the casting procedure is operating, however, the access bore needs to be open in order to gas treat the previously shot-in sand, which can be achieved by a deeper insertion position relative to the operational position during installation, while circumferential sealing between the leveling rod or the alignment insert on the one hand and the access bore on the other only takes place at this deeper position, but not at the operational position differing therefrom.

The invention further relates to a sand casting tool, which is designed for the production of sand castings. Said sand casting tool comprises a mold element having a mold recess which at least partially defines the contour of the sand casting to be manufactured. The sand casting tool further comprises at least one leveling rod, which is insertable through an access bore aligned in the direction of a Z-axis in the mold element from an external surface of said mold element to at least the mold recess, and a distal end of the leveling rod predominantly closes the opening of the access bore on the mold recess side when said leveling rod is in an operational position.

Provision is made for adaptation of the shapes of the access bore and the leveling rod to each other in such a way that, in an mounting state in which the leveling rod is inserted in the access bore, the mobility of the leveling rod relative to the mold is restricted such that the leveling rod is translatively displaceable by a maximum of 0.5 mm relative to the mold element in the direction of an X-axis and in the direction of a Y-axis, said axes being orthogonally aligned to each other and to the Z-axis, and such that the leveling rod is rotatably tiltable about the X-axis and the Y-axis by a maximum of 3° in each case.

This adaptation of the access bore to the leveling rod makes it possible to carry out the installation method described above. The shapes of the leveling rod and the access bore are adapted to each other in such a way that, in the mounting state, the maximum values of 0.5 mm translative displaceability and 3° tiltability are achieved. Preference is given to the achievement of a maximum of 0.3 mm translative displaceability, more preferably a maximum of 0.2 mm. Preference is given to a maximum tiltability of 2°, more preferably a maximum of 1°.

The invention also relates to a modification of this sand casting tool in which an alignment insert is provided, which is insertable together with the leveling rod into the access bore, the shapes of the access bore, the alignment insert, and the leveling rod being adapted to each other such that, in an mounting state with the leveling rod and the alignment insert inserted in the access bore, the freedom of movement of the leveling rod relative to the mold element is restricted in the aforementioned manner.

With this variant, the alignment of the leveling rod to the mold element is thus not solely achieved by surfaces provided directly on the mold element and directly on the leveling rod, but by interposition of the alignment insert, which is also inserted into the access bore, at least during an installation procedure.

Such an alignment insert can be for example in the form of an alignment ring, which in the mounting state abuts the inside of the access bore with its outside surface and abuts the leveling rod with its inside surface. An element open at both ends, which completely or almost completely surrounds the leveling rod, is considered as such an alignment ring. In the simplest case, such an alignment ring circumferentially abuts the access bore with its outside surface and circumferentially abuts the leveling rod with its inside surface. Particular preference, however, is given to an embodiment in which the alignment ring only partially abuts the access bore with its outside surface, in order to reduce friction between said alignment ring and said access bore.

In an alternative embodiment, an alignment cap is provided in lieu of an alignment ring, which cap is placed on the distal end of the leveling rod. Such an alignment cap is particularly advantageous in the case of cylindrical leveling rods in which the cap configuration defines the relative arrangement of the leveling rod in the direction of the Z-axis, since the cap can only be pressed onto the distal end of the leveling rod to a limited extent and thus assumes a defined position in the direction of the Z-axis relative to a main section of the leveling rod.

The alignment insert can be provided as a separate element, which is co-inserted into the access bore only for installation purposes, but is detached from the leveling rod when the molding apparatus is in use. In such a case, preference is given to the provision of a clearance between the leveling rod and the alignment insert. In an alternative embodiment, provision is made for attachment of the alignment insert to the leveling rod, for example by shrink fitting. An alignment insert thus attached simplifies installation, as there is no need to remove the alignment insert after the installation.

The alignment insert is preferably mounted on the leveling rod in such a way that, upon reaching the operational position of the leveling rod, the insert does not close, at least not completely, an annular gap between the leveling rod and the inside surface of the access bore. Such an arrangement of the alignment insert enables said alignment insert to remain seated on the leveling rod during operation. This is achieved in that there is no contact, or at least no circumferential contact, between the alignment insert and the access bore in the operational state, i.e., when the distal end of the leveling rod is flush with the contour of the mold recess.

Preferably, the sand casting tool has a leveler holding device, which is guided or is at least displaceable in the direction of the Z-axis relative to the mold element and to which the leveling rod can be attached by means of a securing element, which securing element allows for adjustment of the position of attachment of the leveling rod on the leveling rod holding device in the direction of the X-axis and/or in the direction of the Y-axis. By means of the securing element, the leveling rod holding device, which, with the use of a plurality of leveling rods, is used as a leveling rod holding device common to said plurality of leveling rods, makes it possible to mount the leveling rods in a position that is adjustable to a limited extent relative to the leveling rod holding device. It is therefore not necessary to make precise provisions for the arrangement of the leveling rods on the leveler holding rod device. Instead, the securing element allows for at least a certain degree of displaceability, preferably at least 2 mm, and thus for flexible attachability of the leveling rods on the leveling rod holding device. The securing element can be preferably configured such that attachment of the leveling rod holding device within a prespecified angular range is possible, this being realizable by means of, say, a ball joint-shaped end section on the leveling rod.

A particularly simple way of achieving flexible attachability for the leveling rod is given when the securing element comprises a threaded bore in the leveling rod, a matching screw, and a through bore in the leveling rod holding device, wherein the through bore has an inside diameter greater than the outside diameter of the thread of the screw to ensure adjustability of the position of attachment. Alternatively, a male thread can be provided directly on the leveling rod, which is inserted through the through bore so that it can be secured on the opposite side thereof with a nut. In these embodiments, the adjustability of the position of attachment is thus achieved by the size of the through bore compared with the diameter of the screw thread or the diameter of the male thread on the leveling rod.

Preference is given to the provision of a plurality of leveling rods on the sand casting tool, in each case with assigned access bores in the leveling rod holding device, the individual leveling rods being in each case attachable by means of a separate securing element to a common leveling rod holding device. The respective separate securing elements make it possible to compensate the specific manufacturing tolerances concerning the leveling rods and concerning the access bores individually and specifically for each leveling rod/access bore combination.

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects and features of the invention will be evident not only from the claims but also from the following description of a preferred embodiment of the invention, which is explained below and in which

FIG. 1 shows a sand casting tool of the invention,

FIGS. 2a-2d depict installation steps for the installation of the sand casting tool shown in FIG. 1, and

FIGS. 3a-3d show different variants of a leveling rod of the sand casting tool of the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

FIG. 1 shows a sand casting tool of the invention. Said tool comprises two mold halves 10, 12, which in each case have a mold recess 14a, 14b, which jointly form a mold cavity 14, the contour of which represents the contour of a sand casting to be produced. For simplification purposes, the mold cavity 14 is substantially rectangular in the present case. In other embodiments, the mold cavity 14 can have a more complex shape, which has no effect on either the object or the method of the invention except for necessary adjustments to the lengths of the leveling rods as explained below.

The mold halves 10, 12 are mounted on base plates 16, 18, and together with these base plates 16, 18 are displaceable relative to each other in the direction of a Z-axis. This makes it possible to separate the mold halves 10, 12 from each other in order to remove a sand casting from the mold cavity 14.

To manufacture such a sand casting, sand is shot into the mold cavity 14 after closure of the mold halves 10, 12. This takes place through shooting bores 20 provided for this purpose, these extending from a side of the base plate 16 facing away from the mold half 10 through said base plate 16 and through said mold half 10 to the mold recess 14a. The bores 20 have three substantially cylindrical regions 20a, 20b, 20c which are demarcated from each other by steps and have diameters that taper toward the mold recess 14a. Below the last cylindrical section 20c there are two conical sections 20d, 20e, in the direction of which the diameter of the shooting bores 20 further tapers toward the mold cavity 14.

In each shooting bore 20 there is provided a leveling rod 30, each leveling rod 30 having a substantially cylindrical bottom section 30a and a cylindrical top section 30b which is wider than the bottom section. The leveling rods 30 are attached by means of screws 32 to a leveling rod holding device configured as a leveling plate 40. Together with said leveling rod plate 40, the leveling rods 30 are displaceable in the direction of the Z-axis relative to the mold elements 10, 12.

During operation, the leveling rods 30 mounted on the leveling plate 40 are pushed into the shooting bores 20 after the mold cavity 14 has been filled with sand, in order to press any sand remaining in the vicinity of the bottom end 20e of the bores 20 into the mold cavity 14 and to provide, by means of their end faces 30c, a boundary surface that is flush with the rest of the contour of the mold cavity 14a. The position that the leveling rods 30 assume in this operational condition is shown in FIG. 1. This position of the leveling rods 30 in the operational condition is maintained when the sand in the mold cavity 14 is subsequently treated with gas, in order to produce a dimensionally stable body. This gas treatment takes place through the shooting bores 20, and said gas treatment takes place at the bottom end 20e of the shooting bores 20 through an annular gap 50 remaining between the end faces 30c of the leveling rods 30 and the rim of the bore 20.

Since the annular gap 50 is very narrow in order to ensure a flawless surface for the sand casting, the leveling rods 30 must be very precisely aligned relative to the leveling plate 40 and to each other. With incorrect alignment, the ends 30c of the leveling rods will reside in the sections 20e of the bore 20 in the operational state shown in FIG. 1. This is not desirable. Furthermore, an incorrect alignment of the leveling rods 30 results in damage to the leveling rods 30 and/or to the bore 20 as the leveling rods 30 are inserted into, or withdrawn from, said bores 20.

In order to ensure this precise alignment, the installation method illustrated with reference to FIGS. 2a-2d is employed.

As can be seen from FIG. 2a, the leveling rods 30 are equipped with alignment rings 60, at least for installation purposes. These alignment rings are slid onto the top end of the cylindrical region 30b, which cylindrical region 30b is slightly widened at this top end. The alignment rings 60 together with the leveling rods 30 form a narrow clearance fit or a press fit. In the variant with a clearance fit, provision is made for removal of the alignment rings 60 upon completion of the installation. In the alternative variant involving a press fit, the alignment rings stay on the leveling rods. In this case a shrink fitting method is used to fix the alignment rings 60 onto the leveling rods 30.

In a state in which the leveling rods 30, with the alignment rings 60 in position thereon, are not yet attached to the plate 40, said leveling rods 30 are individually inserted into the respective shooting bores 20, the outside diameter of the alignment rings 60 being adapted to the inside diameter of the respective shooting bores in the region 20b such that there is a clearance fit. Accordingly, when the leveling rods 30 are inserted in the direction 2 into the bores 20, the alignment ring comes into contact with the bore wall in the region 20b of the bores 20, thus achieving the condition illustrated by the left-hand leveling rod 30 in FIG. 2a. In this mounting state, the leveling rod 30 is inserted distinctly further into the shooting hole 20 than in the operational condition shown in FIG. 1, so that the end 30c of the leveling rod 30 projects comparatively far into the mold recess 14a.

As a result of the clearance fit between the outside surface of the alignment ring 60 and the bore wall in the region 20b and also the clearance or press fit between the inside surface of the alignment ring 60 and the leveling rod 30, a translative movement of the leveling rod in the direction of the X-axis or in the direction of the Y-axis is possible only to a very limited degree in the mounting state of the left-hand leveling rod 30 shown in FIG. 2a. Furthermore, tilting of the inserted leveling rod 30 about the X-axis or the Y-axis is not possible, because the leveling rod 30 is not only in contact with the bore 20 in the vicinity of the alignment ring 60, but is also held in a largely stable position at its bottom end by the conical section 20e of the bore 20.

Once all of the leveling rods 30 have been inserted into the corresponding bores 20 and have in each case aligned themselves correctly, the leveling plate 40 is positioned as illustrated in FIG. 2b. The leveling rods 30 which are still supported by the alignment rings 60 are then attached to this leveling plate 40 with the screws 32, for which purpose the bores 42 provided in the leveling plate 40 have an inside diameter that is ca. 2 mm larger than the outside diameter of the thread of the screws 32. As a result, the screws 32 are displaceable in the direction of the X-axis and also in the direction of the Y-axis before tightening; hence it is possible to tighten said screws 32 in the ideal position defined by the alignment of the respective leveling rods 30.

Next, the leveling plate 40 with the leveling rods 30 now attached thereto is raised. Due to the fact that the leveling rods 30 are attached to the leveling plate in the inserted condition, the leveling rods 30 remain in the ideal position relative to the leveling plate 40 and relative to each other. In the case where only temporarily attached alignment rings 60 have been used, the latter can be removed after raising the leveling plate and the leveling rods 30. After raising the leveling plate 40, a spacer 44 is then attached to the underside of the leveling plate 40. The tool is now ready for use.

In operation, the leveling plate 40 with the leveling rods 30 mounted thereon is used in alternation with a nozzle plate (not illustrated), so that the leveling rods 30 are repeatedly withdrawn from the bores 20 and then later reinserted into the bores 20. Due to the optimum alignment of the leveling rods 30 on the leveling plate 40, this can be accomplished without causing significant damage to the bores 20 or to the leveling rods 30.

As has been described with reference to FIG. 1, the leveling rods in an operational condition corresponding to the condition illustrated in FIG. 2c are disposed in such a way that the distal end 30c is aligned flush with the contour of the mold recess 14a. As can be seen in FIG. 2c, the use of temporary alignment rings makes it possible to let gas flow unhindered through the bores 20 during the gas treatment, because there are no other constrictions that could hinder the gas flow in the direction of the path 70 to the annular gap 50. Even when the alignment ring 60 is a permanently-mounted, e.g. a shrink-fitted, annular ring 60 rather than a temporary one, the gas can flow in the direction of a path 72 through an annular gap 52 between the outside surface of the alignment ring 60 and the wall of the bore 20 in the region 20a, which is wider than the region 20b used for alignment.

FIG. 2d shows a mold ejection condition of the leveling rods 30 suitable for the removal of a casting. After the sand casting has been produced, said rods are inserted into the mold recess 14a in order that the sand casting may be effortlessly ejected from the top mold half 10. The spacer 44 determines the maximum insertion depth.

FIGS. 3a to 3d show other embodiments of leveling rods 30. In terms of its use, the leveling rod 30 illustrated in FIG. 3a is similar to the previously described leveling rod 30 of the embodiment shown in FIGS. 1 to 2d. In this case, however, a separate alignment ring is not provided. Instead, the leveling rod 30 has itself an integrally formed alignment flange 62, which assumes the same function as the alignment ring 60.

The embodiment shown in FIG. 3b is a view from above of the leveling rod 30 shown in FIGS. 1 and 2a to 2d and also in FIG. 3a. It can be seen that the alignment ring 60 or the alignment flange 62 is configured as a continuous, closed ring or flange, which completely stops the flow of gas through the bore 20 when it is in its alignment position in the region 20b of said bore 20.

In the embodiment illustrated in FIG. 3c, on the alignment ring 60 or alignment flange 62 there are provided axial through bores 64, which ensure a flow-through even when the periphery of the alignment ring 60 or alignment flange 62 abuts against the inside wall of the bore 20. The use of such an alignment ring 60 or alignment flange 62 is advantageous if the diameter of the bore 20 has, at that position at which the ring 60 or flange 62 is disposed in the operational condition of the leveling rod 30, an inside diameter that is identical to the outside diameter of the ring 60 or flange 62. In such a case, the gas in the region concerned is conducted through, rather than past, the leveling rod 30.

The embodiment shown in FIG. 3d differs from that illustrated in FIG. 3b in that for achieving contact of the alignment ring 60 or alignment flange 62 with the bore 20, no continuous contact surface is provided, but instead, the ring 60 or flange 62 is configured to abut against the bore 20 in three isolated contact regions 66. On the one hand, this enables the gas to be conducted past the alignment ring or alignment flange. On the other hand, this makes it possible to insert the leveling rod 30 during installation and subsequently to withdraw the leveling rod 30 mounted on the leveling plate 40 during installation with less friction occurring between the ring 60 or flange 62 on one hand and the bore 20 on the other hand. Installation is thus facilitated thereby.

Claims

1. A method for installing a sand casting tool comprising

at least one mold element having a mold recess which at least partially defines the contour of a sand casting to be produced,

at least one leveling rod holding device which is displaceable in the direction of a Z-axis relative to said mold element and which is disposed on the side of the mold element facing away from said mold recess,

at least one leveling rod capable of being inserted through an access bore in said mold element from the outside surface of said mold element as far as said mold recess and which can be attached in a fixed position to said leveling rod holding device,

characterized by the following method steps:

A. insertion of the leveling rod in the direction of the Z-axis into the access bore in said mold element,

B. attachment of said leveling rod to said leveling rod holding device.

2. The method as defined in claim 1,

characterized in that

said leveling rod is aligned by insertion thereof in method step A relative to the mold element, by which means the freedom of movement of the leveling rod relative to said mold element is restricted preferably to such an extent that

in the direction of an X-axis and in the direction of a Y-axis aligned orthogonally to each other and to the Z-axis, the leveling rod is translatively movable relative to said mold element by not more than 0.5 mm, and the leveling rod is rotatably tiltable about the X-axis and the Y-axis in each case by not more than 3°.

3. The method as defined in claim 2,

characterized in that,

in method step A, an alignment insert is inserted into said access bore in addition to said leveling rod and said alignment insert ensures, due to touching contact with a wall of said access bore and with said leveling rod, that, in the inserted state, the freedom of movement of said leveling rod relative to said mold element is restricted.

4. The method as defined in claim 1,

characterized in that

the leveling rod is moved, in method step A, into said access bore to such an extent that it protrudes into said mold recess.

5. The method as defined in claim 1,

characterized in that,

in method step A, a plurality of leveling rods are inserted into respectively assigned access bores and, in the following method step B, this plurality of leveling rods are attached to a common leveling rod holding device.

6. A sand casting tool for the production of sand castings, comprising

a mold element having a mold recess which at least partially defines the contour of the sand casting to be produced, and

at least one leveling rod adapted to be moved, through an access bore located in said mold element and aligned in the direction of a Z-axis, from an outside surface of said mold element as far as at least said mold recess, and a distal end of said leveling rod, in an operational position of said leveling rod, closes said mold recess end of said access bore at least substantially flush therewith,

characterized in that

the access bore and the leveling rod are, as regards shape, adapted to match each other such that in an mounting state, in which said leveling rod is inserted in the access bore, the freedom of movement of said leveling rod relative to said mold element is restricted such that

in the direction of an X-axis and in the direction of a Y-axis aligned orthogonally to each other and to the Z-axis, the leveling rod is translatively movable relative to said mold element by not more than 0.5 mm, and

the, leveling rod is rotatably tiltable about the X-axis and the Y-axis in each case by not more than 3°.

7. The sand casting tool according to the preamble of claim 6,

characterized by

an alignment insert adapted to be insertable together with said leveling rod into said access bore, and said access bore, said alignment insert, and said leveling rod are, as regards the shape thereof, adapted to match each other such that in an mounting state, in which said leveling rod and said alignment insert are inserted in said access bore, the freedom of movement of the leveling rod relative to said mold element is restricted to such an extent that

in the direction of an X-axis and in the direction of a Y-axis aligned orthogonally to each other and to the Z-axis, the leveling rod is translatively movable relative to said mold element by not more than 0.5 mm, and

the leveling rod is rotatably tiltable about the X-axis and the Y-axis in each case by not more than 3°.

8. The sand casting tool as defined in claim 7,

characterized in that

said alignment insert is in the form of an alignment ring, which in the mounting state rests with its outside surface against the inside surface of said access bore and with its inside surface against said leveling rod, or is in the form of an alignment cap mounted on the distal end of said leveling rod.

9. The sand casting tool as defined in claim 7,

characterized in that

said alignment insert is firmly attached to said leveling rod.

10. The sand casting tool as defined in claim 9,

characterized in that

said alignment insert is attached to the leveling rod in such a manner that, on acquiring the functional position of the leveling rod, an annular gap between said leveling rod and the inside surface of said access bore is at least not completely closed thereby.

11. The sand casting tool as defined in claim 6,

characterized in that

in the mounting state the translative displaceability of said leveling rod relative to said mold element is restricted in the direction of the X-axis and in the direction of the Y-axis to not more than 0.3 mm and preferably not more than 0.2 mm.

12. The sand casting tool as defined in claim 6,

characterized in that

in the mounting state, the rotatable tiltability of said leveling rod relative to said mold element is restricted to not more than 2°, preferably not more than 1°.

13. The sand casting tool as defined in claim 6,

characterized by

a leveling rod holding device, which is displaceable relative to said mold element in the direction of the Z-axis and can be attached to said leveling rod by means of a securing element, which securing element allows for adjustment of the position of attachment of the leveling rod on the leveling rod holding device in the X-direction and/or the Y-direction.

14. The sand casting tool as defined in claim 13,

characterized in that

said securing element comprises a threaded bore in said leveling rod, a corresponding screw, and a through bore in the leveling rod holding device,

which through bore has an inside diameter which, for the purpose of ensuring adjustability of the position of attachment, is greater than the outside diameter of the thread of said screw.

15. The sand casting tool as defined in claim 6,

characterized in that

a plurality of leveling rods with assigned access bores is provided, and the individual leveling rods are capable of being attached via a separate securing element to a common leveling rod holding device.