EP0454098B1 - Process for making the bottom piece of a shaft and apparatus for carrying out the process - Google Patents

Abstract

A manhole floor piece (10) with a side wall (10b) and an integrally connected floor (10a) consisting of concrete exhibits a floor insert element (34), of which the outer contour (34a), at least partially projecting outwards beyond the inner contour of the side wall (10b), is embedded in the concrete, the concrete of the floor (10a), past the floor insert element (34), being integral with the concrete of the side wall. <IMAGE>

Description

The invention relates to a method for producing shaft floor pieces according to the preamble of claim 1.

In the conventional production of molded concrete parts in a substantially pot-shaped form, in particular of manhole bases or manhole bottoms, as a consequence of the removal of the formwork prior to curing, the problem arose that the base of the molded concrete part deformed under its own weight during the period from the formwork removal to complete hardening . Reference is also made to the description of FIGS. 8 and 9.

To solve this problem, a generic method has been proposed, for example, in DE-A-35 15 986, in which the bottom of the molded concrete part is supported by an inner, recoverable formwork panel until it has completely hardened which in turn is carried through an opening formed in the bottom by a holding plate placed after the filling and supported over the side wall. After curing, the two plates must be removed by hand from the bottom of the molded concrete part. In addition, the opening in the bottom of the concrete molding must be poured with concrete. In addition, reference is made to the description of FIGS. 10-14.

In addition, it is known from DE-A-35 15 986 to support the insert element by means of supporting parts connected to it and engaging in the side wall, for example by means of recess cores for forming inlets and outlets for a channel. Both the support parts and the insert element are removed from the manhole base piece after it has completely hardened and reused after any cleaning.

The method of the generic type has various disadvantages: firstly, productivity is reduced by the large number of necessary work steps, in particular by the manual attachment and removal of the support plates and the like parts. On the other hand, the concrete subsequently poured into the floor opening does not form a perfect, in particular no watertight, bond with the concrete molding.

In contrast, it is an object of the invention to provide a method of the type mentioned, which enables the production of molded concrete parts with a perforation-free and non-deformed bottom with high productivity.

This object is achieved by using a lost insert element, the outer circumference of which protrudes at least over part of the circumference of the mold core in the radial direction and forms a filling cross section sufficient for filling the mold cavity with the inner circumference of the mold shell.

After the mold has been filled with concrete and the filled-in concrete has been compacted, the outer circumference of the insert element, which projects radially beyond the outer circumference of the mold core, is embedded in the concrete. The insert element supports the bottom of the molded concrete part and distributes its weight over its embedded part in the concrete Outer circumference on the side wall of the molded part. In this way, deformations of the bottom of the concrete molding can be reliably prevented without an opening in the bottom having to be provided to support the weight of the bottom. After hardening, the insert element remains as lost formwork in the concrete molding.

From FR-A-1 591 446 a process for the production of concrete beams or slab elements is known. In this method, lost insert elements are used to form internal cavities of the supports or plate elements.

US-A-1 611 287 describes a process for the production of asphalt coffins which are provided with a metal lining in their base. The metal lining overlies a grid forming the top of the mandrel. With this known method, the formwork is removed only after the asphalt coffin has fully hardened.

Advantageous and preferred developments of the method according to claim 1 are specified in the dependent claims:
In one embodiment, the insert element can be designed as an insert plate or insert shell.

In order to be able to further stabilize the insert plate for supporting the weight bearing on it, a further development of the invention proposes that the insert element be provided with stiffening ribs on its side facing away from the mandrel.

Alternatively, however, it can also be provided that reinforcement elements, in particular made of structural steel, are placed on the side of the insert plate facing away from the mandrel.

Because the insert element is convex, the insert element being laid with its concave side on the upper end of the mandrel, the insert element can be given a high degree of stability in a particularly simple manner.

As an alternative to this, it can also be provided that the insert element is conical, the insert element being placed with its concave side on the upper end of the mandrel.

Because the insert element is formed with a channel, the concrete molding can also be used to guide water. Here, the channel does not have to be straight, but can also be curved within the molded concrete part.

In order to be able to connect line pipes in the molded concrete part, it is proposed that the insert element for the formation of inlets and / or outlets has essentially tubular approaches.

In order to be able to reliably ensure that the mold cavity is filled properly, it is proposed that the filling cross section be at least 30%, preferably between 40% and 90%, of the cross section of the mold cavity.

In a development of the invention it is proposed that the outer circumference of the insert element runs at a substantially constant distance from the outer circumference of the mandrel. It can be provided that the distance of the outer circumference of the insert element from the inner circumference of the molded casing is at least 20% of the distance at the respective point between the outer circumference of the molded core and the inner circumference of the molded casing, preferably between 30% and 90%, for complete filling of the mold cavity with concrete.

Alternatively, it is proposed that the outer circumference of the insert element has projections projecting radially outward. It is further preferred that the projections are distributed over the circumference of the insert element and have an angular distance of 15 ° to 120 °, preferably approximately 60 °, and that each projection has an average angular extent of 5 ° to 15 °, preferably approximately 10 ° has. This can ensure an effective distribution of the weight of the bottom of the molded concrete part on the side wall, while at the same time it can be ensured that the concrete fills the mold completely, ie in particular without voids under the outer peripheral edge of the insert element.

In a further development of the invention it is proposed that an insert element made of timber, pressboard, plastic, metal or fiber-reinforced cement is used. Preferably, an insert element made of a material that adheres to concrete can be used.

Furthermore, the side wall can be built up when pouring the concrete on a lower sleeve, which forms the lower end of the mold cavity. The stripping can then be carried out by lifting the lower sleeve to a height approximately corresponding to the upper end of the shaped jacket. Finally, the bottom part of the manhole can be transported away from the upper end of the shaped jacket.

It is also proposed to shake the mold to evenly distribute the filled concrete.

With the method according to the invention, for example, manhole base pieces with a circular cross section can be produced.

According to a further aspect, the invention relates to a device for carrying out the method according to the invention for producing manhole base pieces with a side wall and an integrally adjoining floor made of concrete in a manufacturing orientation opposite to the usage orientation, ie with the floor facing upwards, the device having a shape with a mold core and a radially outer mold jacket arranged at a distance from the mold core, an insert element placed on the upper end of the mold core, a compacting device for compacting the mold into the mold filled concrete, and a lifting device for lifting the shaft base piece from the mold, and wherein according to the invention the outer circumference of the insert element projects at least over a part of the circumference in the radial direction of the outer circumference of the mold core and with the inner circumference of the mold shell one for filling the mold cavity forms sufficient filling cross section.

In this device, the mold can have a lower sleeve which forms the lower end of the mold cavity. In this case, the lower sleeve can lie on the lifting device to lift the shaft base piece to a height approximately corresponding to the upper end of the shaped jacket. Furthermore, a transport device, in particular a fork-lift truck, can be provided for the joint removal of the manhole base piece with the lower sleeve from the upper end of the shaped jacket.

The device according to the invention can further comprise concrete feeding means for feeding the concrete to be poured into the mold, and a vibrating device for evenly distributing the concrete poured into the mold.

According to a further aspect, the invention relates to a concrete manhole base piece produced by the method according to the invention with an insert element embedded therein.

Fig. 1

eine geschnittene Seitenansicht zur Erläuterung des erfindungsgemäßen Verfahrens zur Herstellung von Betonformteilen;

Fig. 2

eine geschnittene Seitenansicht einer ersten Ausführungsform eines nach dem erfindungsgemäßen Verfahren hergestellten Betonformteils im entschalten Zustand;

Fig. 3 - 6

Ansichten analog Fig. 2 weiterer Ausführungsbeispiele von nach dem erfindungsgemäßen Verfahren hergestellten Betonformteilen;

Fig. 7

eine schematische Darstellung zur Erläuterung des Verlaufs des Außenumfangs des Einleg-Elements;

Fig. 8 und 9

Ansichten analog den Fig. 1 und 2 zur Erläuterung eines bekannten nicht gattungsgemäßen Verfahrens; und

Fig. 10 - 14

Ansichten zur Erläuterung eines in Betracht gezogenen, gattungsgemäßen Verfahrens; hierbei ist:

Fig. 10

eine Ansicht analog den Fig. 1 und 8;

Fig. 11

eine geschnittene Seitenansicht eines nach diesem Verfahren hergestellten Betonformteils;

Fig. 12

eine Ansicht analog den Fig. 2 und 9;

Fig. 13

eine Ansicht des nach diesem Verfahren hergestellten Betonformteils nach Abnahme der Platten; und

Fig. 14

das nach diesem Verfahren hergestellte Betonformteil in seiner Gebrauchslage mit ausgegossener Bodendurchbrechung.

The invention is explained below with reference to the drawing. They represent:

Fig. 1

a sectional side view for explaining the inventive method for producing molded concrete parts;

Fig. 2

a sectional side view of a first embodiment of a molded concrete part produced by the method according to the invention in the detached state;

3 - 6

Views analogous to FIG. 2 of further exemplary embodiments of molded concrete parts produced by the method according to the invention;

Fig. 7

a schematic representation to explain the course of the outer circumference of the insert element;

8 and 9

Views analogous to Figures 1 and 2 to explain a known method not generic; and

Figures 10-14

Views for explaining a generic method under consideration; here is:

Fig. 10

a view analogous to Figures 1 and 8;

Fig. 11

a sectional side view of a concrete molding produced by this method;

Fig. 12

a view analogous to Figures 2 and 9;

Fig. 13

a view of the molded concrete part produced by this method after removal of the plates; and

Fig. 14

the molded concrete part produced according to this process in its position of use with poured-out opening in the bottom.

In a known, non-generic method for the production of essentially pot-shaped concrete molded parts, namely shaft base pieces 10 ', a mold 12 is used according to FIG. 8, which consists of a mold core 14, a mold jacket 16, a lower sleeve 18 and a mold upper part 20. The upper mold part 20 can be transferred from a lowered position (see FIG. 8) to a raised position and vice versa by means of a lifting device (not shown in FIG. 8). For this purpose, the upper mold part 20 can be moved in a direction running essentially parallel to the axis of the mold core 14 and indicated by the double arrow A in FIG. 8. The lower sleeve 18 can be moved between a lower position (see FIG. 8) and an upper position (see FIG. 8) by means of a lifting device 22 in a direction that is also essentially parallel to the axis of the mandrel 14 and is indicated in FIG. 8 by the double arrow B. . 9) can be adjusted.

The mold jacket 16 runs at a radial distance from the outer circumference 14a of the mold core 14. In the axial direction, the mold jacket 16 projects beyond the upper boundary surface 14b of the mold core 14. The lower sleeve 18 is arranged radially between the mold core 14 and the mold jacket 16 and stands on the surface shown in FIG. 8 upper end 22a of the lifting device 22.

In the manufacture of manhole base pieces 10 ', the known method proceeds as follows: If the lifting device 22 with the lower sleeve resting on it 18 is in the lower position (cf. FIG. 8) and the upper mold part 20 is in the raised position, a predetermined amount of concrete is placed in a mold cavity 24 defined by the mold core 14, the lower sleeve 18 and the mold jacket 16 beyond the upper boundary surface 14b of the mandrel 14 filled. The concrete layer above the upper boundary surface 14b of the mold core 14 is then smoothed by lowering the upper mold part 20. For compaction, the entire mold 12 can be shaken by a vibrating device, not shown, in order to achieve a uniform distribution of the filled concrete. Thereafter, the lower sleeve 18 and with it the manhole base piece 10 'are moved out of the mold 12 by the lifting device 22 and are thus released (see FIG. 9). In Figure 9, the lower sleeve 18 is approximately flush with the floor of the manufacturing hall. The shaft base piece 10 'is then brought together with the lower sleeve 18 to a storage location by a transport device, for example a forklift truck, where it preferably remains until the concrete has completely hardened.

The above-described manufacturing method for manhole base pieces 10 'has the disadvantage that the bottom part 10'a deforms during the period from the formwork to the complete hardening of the concrete due to its own weight (see FIG. 9), since the filled concrete withstands tensile stresses is not dimensionally stable. In the worst case, the bottom part can get 10'a cracks. Since the filled-in concrete is dimensionally stable against pressure loads, the side wall 10'b of the manhole bottom piece 10 'is not subject to any deformation.

In order to avoid the disadvantage of deformed floor parts, a method was considered, which will be explained in the following with reference to FIGS. 10-14.

In this method, before the mold cavity 24 of the mold 12 is filled with concrete, an inner formwork plate 26 (see FIG. 10), which is provided with a spacer 26a and a screw bolt 26b, is placed on the upper end 14b of the mold core 14. The upper mold part 20 'has a recess 20'b formed at its lower end 20'a, in which the screw bolt 26b of the plate 26 is received when the upper mold part 20' is in its lowered position.

After compaction, the upper mold part 20 'is raised again and a holding plate 28 is placed on the manhole bottom piece 10' '. The holding plate 28 is firmly connected to the formwork plate 26 via a locking screw nut 30 screwed onto the screw bolt 26b (see FIG. 11). The diameter of the formwork plate 26 corresponds to the diameter of the mold core 14, while the holding plate 28 extends up to the inner circumference 16a of the mold jacket 16 and is supported on the side wall of the shaft base piece 10 ″. The shaft base piece 10 ″ is then removed from the mold by extending the lifting device 22 (see FIG. 12) and, as described above, removed for the hardening of the concrete. In this state, the base part 10 ″ a of the shaft base piece 10 ″ is received between the plates 26 and 28 and is supported by them, so that it cannot deform under its own weight.

After curing, the locking screw nut 30 is loosened and the plates 26 and 28 are removed from the manhole base piece 10 ″ (see FIG. 13). Since the spacer 26a was also removed with the plate 26, an opening 10''c remains in the bottom part 10''a of the manhole bottom piece 10 ''. This opening 10 ″ c is filled with mortar 32 after the manhole bottom piece 10 ″ has been brought into its position of use according to FIG. 14.

Although this method prevents deformation of the base part 10 ″ a of the manhole base piece 10 ″, it has some serious disadvantages: on the one hand, the plates 26 and 28 have to be attached and removed again by hand, which results in a considerable reduction in productivity. On the other hand, after the plates 26 and 28 have been removed, an opening 10 ″ c remains in the base part 10 ″ a of the manhole base piece 10 ″ and must be filled with mortar 32 in an additional work step. Since this mortar 32 does not connect to the already hardened concrete to a sufficient extent, it cannot be guaranteed that the manhole base piece is watertight.

In the following, the method according to the invention is to be described in detail with reference to FIGS. 1 and 2, which is characterized by high productivity and with which the production of reliably watertight manhole base pieces is made possible.

The method according to the invention can be carried out with the same device with which the known method, not of the generic type and described above with reference to FIGS. 8 and 9, was carried out. The method according to the invention differs from the known method of the generic type in that before the mold cavity 24 is filled with concrete, an insert element 34, for example an insert plate (see FIG. 1), on the upper end 14b of the mandrel 14 is placed, which has an outer diameter D₂ (see. Fig. 2), which is larger than the outer diameter D₁ of the concrete mold core 14. That is, the insert plate 34 is dimensioned such that its outer circumference 34a, seen in the radial direction, between the outer circumference 14c of the upper end 14b of the mold core 14 and the inner circumference 16a of the mold jacket 16.

The insert element 34 can be made, for example, of construction timber, pressboard, plastic, metal, fiber-reinforced cement or the like. Preferably, a material that adheres to concrete is used.

When the mold cavity 24 is filled, the concrete flows between the outer circumference 34a of the insert plate 34 and the inner circumference 16a of the mold jacket 16 to the lower sleeve 18. After smoothing the filled concrete through the mold upper part 20, if necessary with simultaneous shaking, for uniform distribution of the filled Concrete, the manhole bottom piece 10 is released by extending the lifting device 22 (see FIG. 2). The shaft base piece 10 is then transported to a storage location together with the lower sleeve 18 using a transport device, for example a forklift truck, and is left there until it has completely hardened.

During this period, the insert plate 34 picks up the weight of the base part 10a of the manhole base piece 10 and distributes this weight in the area of its outer circumference 34a to the side wall 10b of the manhole base piece 10. This reliably prevents deformation of the base part 10a without breaking through it To have to accept bottom part 10a. After hardening, the insert plate 34 remains as lost formwork in the shaft bottom piece 10.

In order to increase the stability of the bottom part 10a of the manhole base piece 10 and to provide a stiffening for the insert plate 34, additional inserts, for example in the form of structural steel rods 36, can be placed on the insert plate 34 before the mold 12 is filled with concrete. Alternatively, it is also possible to provide the insert plate 34 with stiffening ribs on its side facing away from the mandrel 14.

FIG. 4 shows a further exemplary embodiment of a manhole base piece produced by the method according to the invention, analog parts being provided with the same reference numerals as in FIGS. 1 and 2, but increased by the number 100.

In this exemplary embodiment, the insert element 134 is of slightly convex design. Due to the shape that bulges out in the direction of the bottom part 110a of the manhole base piece 110 that bears on it, the insert element 134 has better statics. Thus, insert elements 134 made of lighter and less stable materials can also be used for the production of manhole bottom pieces according to the method according to the invention.

A further exemplary embodiment of a manhole base piece produced by the method according to the invention is shown in FIG. 5, analog parts being provided with the same reference numerals as in FIGS. 1 and 2, but increased by the number 200.

In this exemplary embodiment, the insert element 234 has a conical shape, the tip of the cone being directed toward the bottom part 210a of the shaft base piece 210 which bears on the insert element 234. The conical shape also has good static properties, so that the use of such an insert element 234 has the same advantages as the use of a convex insert element 134 described above.

FIG. 6 shows a further exemplary embodiment of a manhole base piece produced by the method according to the invention, analog parts being provided with the same reference numerals as in FIGS. 1 and 2, but increased by the number 300.

In this exemplary embodiment, the insert element 334 not only takes on the supporting function for the base part 310a of the manhole bottom piece 310, but at the same time also takes on the function of water guidance. For this purpose, the insert element 334 is formed with a channel 334a. In order to enable the connection of piping systems, not shown in FIG. 6, to the shaft bottom piece 310, the insert element 334 is provided on its channel 334a with an essentially tubular extension 334b. When the lifting device 322 is retracted, this projection 334b lies in a form-fitting manner between the mold core 314 and the molding jacket 316, so that when the mold is filled with concrete, it cannot penetrate into the space 334b1 enclosed by the tubular projection 334b. A manhole bottom piece 310 can have a plurality of such inflow or outflow approaches 334b. The channel 334a does not have to run in a straight line in the shaft bottom piece 310, but can also take a curved course.

When dimensioning the outer circumference of the insert element between the outer circumference of the mandrel and the inner circumference of the mold shell, it is desirable, on the one hand, to make the outer circumference of the insert element as large as possible in order to ensure good distribution and support of the load on the insert element To reach the weight of the bottom part of the manhole base. On the other hand, it is desirable to make the outer circumference of the insert element as small as possible, in order to be able to ensure that the concrete actually actually completely flows under the insert element when the mold is filled.

It has been found that these two mutually opposing requirements can be met in a particularly favorable manner at the same time by forming the insert element according to FIG. 7 with projections 38 projecting radially outward from its outer circumference 34a. With these projections 38 that extend almost to the inner circumference 16a of the mold jacket 16, the insert element 34 can effectively distribute the weight of the bottom part 10a of the manhole bottom piece 10 resting on it to the side wall 10b of the manhole bottom piece, while filling concrete into the mold cavity 24 (see FIG. 1) Concrete can flow past the insert element without any problems through spaces 40 provided between the projections 38 (see FIG. 7) and can completely fill the mold cavity 24.

Claims (27)

1. A method for the production of shaft bottom pieces having a side wall (10b) and an integrally adjoining bottom (10a) made of concrete,
      said shaft bottom pieces (10) being formed in a mould (12) in a manufacturing orientation which is inverted with respect to the service orientation, i.e. with said bottom being directed upwardly, said mould comprising a mould core (14) and a radially outer mould mantle (16) distanced from said mould core (14),
      said method comprising the steps of:

   a) laying an inlay element (34) onto the upper end portion (14b) of said mould core (14);

   b) filling concrete into a mould cavity (24) formed between said mould core (14) and said mould mantle (16) until said inlay element (34) is completely covered by a layer of desired thickness;

   c) compacting the concrete filled in;

   d) removing said shaft bottom piece (10) from said mould by lifting said shaft bottom piece out of the mould; and

   e) allowing said shaft bottom piece (10) to harden,

   said shaft bottom piece (10) remaining in the manufacturing orientation at least until the hardening step has been terminated,
   characterised by the use of a dead inlay element (34), the outer periphery (34) of which overlaps at least over a part of the periphery the outer periphery (14c) of said mould core (14) in radial direction and defines with the inner periphery (16a) of said mould mantle (16) a filling cross-section sufficient for filling said mould cavity (24).
2. Tie method according to claim 1,
   characterised in that said inlay element is designed as an inlay plate (34) or an inlay shell.
3. The method according to one of claims 1 or 2,
   characterised in that said inlay element (34) has stiffening ribs provided at that side thereof which is remote from said mould core (14).
4. The method according to one of claims 1 to 3,
   characterised in that reinforcing elements (36), in particular made of structural steel, are laid upon that side of the inlay element (34) which is remote from said mould core (14).
5. The method according to one of claims 1 to 4,
   characterised in that said inlay element (134) is embossed, said inlay element (134) being laid with its concave side onto the upper end portion (114b) of said mould core (114).
6. The method according to one of claims 1 to 4,
   characterised in that said inlay element (234) is conically shaped, said inlay element (234) being laid with its concave side onto the upper end portion (214b) of said mould core (214).
7. The method according to one of claims 1 to 6,
   characterised in that said inlay element (334) is formed with a flume (334a).
8. The method according to one of claims 1 to 7,
   characterised in that, for forming inflows and/or outflows, said inlay element (334) comprises substantially tubular projections (334b).
9. The method according to one of claims 1 to 8,
   characterised in that the filling cross-section is at least 30 %, preferably between 40 % and 90 % of the cross-section of said mould cavity (24).
10. The method according to one of claims 1 to 9,
    characterised in that the outer periphery (34a) of said inlay element (34) has a substantially constant distance from the outer periphery (14c) of said mould core (14).
11. The method according to claim 10,
    characterised in that the distance between said outer periphery (34a) of said inlay element (34) and the inner periphery (16a) of said mould mantle (16) is at least 20 % of the distance at the respective position between the outer periphery (14c) of said mould core (14) and the inner periphery (16a) of said mould mantle (16), preferably between 30 % and 90 %.
12. The method according to one of claims 1 to 9,
    characterised in that said outer periphery (34a) of said inlay element (34) has radially outwardly projecting protrusions (38).
13. The method according to claim 12,
    characterised in that said protrusions (38) are uniformly distributed over the periphery of said inlay element (34) and have an angular distance of 15° to 120°, preferably of approximately 60°, and that each protrusion has a mean angular extension of 5° to 15°, preferably of approximately 10°.
14. The method according to one of claims 1 to 13,
    characterised in that an inlay element (34) is used which is made from timber, presspahn, plastic, metal or fiber-reinforced cement.
15. The method according to one of claims 1 to 14,
    characterised in that an inlay element (34) is used which made of a material adheringly binding to concrete.
16. The method according to one of claims 1 to 15,
    characterised in that said side wall (10b) is formed on a lower mould ring (18) as the concrete is filled in, said lower mould ring forming the lower terminal portion of said mould cavity (24).
17. The method according to claim 16,
    characterised in that said shaft bottom piece (10) is removed from said mould by lifting said lower mould ring (18) to a level which corresponds approximately to the upper end portion of said mould mantle (16).
18. The method according to claim 17,
    characterised in that said shaft bottom piece (10) is transported away from the upper end portion of said mould mantle (16) together with said lower mould ring (18).
19. The method according to one of claims 1 to 18,
    characterised in that said mould (12) is vibrated for evenly distributing the concrete filled in.
20. The method according to one of claims 1 to 19 for the production of shaft bottom pieces (10) of circular cross-section.
21. An apparatus for carrying out the method according to one of claims 1 to 20 for the production of shaft bottom pieces (10) comprising a side wall (10b) and an integrally adjoining bottom (10a) made of concrete in a manufacturing orientation which is inverted with respect to the service orientation, i.e. with the bottom (10a) being directed upwardly, said apparatus comprising:
       a mould (12) including a mould core (14) and a radially outer mould mantle (16) distanced from said mould core (14);
       an inlay element (34) laid onto the upper end portion (14b) of said mould core (14);
       a compacting device for compacting the concrete filled into said mould (12); and
       an lifting device (22) for lifting said shaft bottom piece (10) out of said mould (12),
    characterised in that the outer periphery (34a) of said inlay element (34) overlaps at least over a part of the periphery (34a) the outer periphery (14c) of said mould core (14) in radial direction and defines with the inner periphery (16a) of said mould mantle (16) a filling cross-section sufficient for filling said mould cavity (24).
22. The apparatus according to claim 21,
    characterised in that said mould (12) comprises a lower mould ring (18) forming the lower terminal portion of said mould cavity (24).
23. The apparatus according to claim 22,
    characterised in that said lower mould ring (18) rests on said lifting device (22) for lifting said shaft bottom piece (10) to a level which corresponds approximately to the upper end portion of said mould mantle (16).
24. The apparatus according to claim 23,
    characterised in that a transporting device, particularly a fork lift truck, is provided for the common transport of said shaft bottom piece (10) and said lower mould ring (18) away from the upper end portion of said mould mantle (16).
25. The apparatus according to one of claims 21 to 24,
    characterised in that it further comprises concrete feeding means for feeding the concrete to be filled into said mould (12).
26. The apparatus according to one of claims 21 to 25,
    characterised in that it further comprises a vibrating device for evenly distributing the concrete filled into said mould (12).
27. A concrete shaft bottom piece (10) including an inlay element (34) embedded therein, produced according to a method according to anyone of claims 1 to 20.

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