Inner formwork

Abstract

Internal formwork (1) for concrete construction, comprising a number of corner units (10) between which formwork panels (11) are arranged, wherein the corner units (10) have a base element (12) and two sliding elements (13) to which the formwork panels (11) are attached, and wherein the sliding elements (13) are movable along a base surface of the base element (12) by activating a spindle or a push rod (14), characterized in that at least one ejection means (15) is provided on the base element (12) with which the base element (12) can be ejected from the finished concrete casting.

Description

[0001] The invention relates to an internal formwork for concrete construction, comprising a number of corner units between which formwork panels are arranged, wherein the corner units have a base element and two sliding elements to which the formwork panels are attached, and wherein the sliding elements can be moved along a base surface of the base element by activating a spindle or a push rod. STATE OF THE ART

[0002] A generic internal formwork in the form of a shaft internal formwork is known, for example, from CN 104295091 A. The corner units have spindles that can be rotated by means of a tool wrench, thereby allowing the sliding elements on the triangular base element or on its base surface to be moved towards and away from each other. For this purpose, a coupling mechanism is incorporated between the spindle and the sliding elements in the corner units, so that the rotation of the spindle triggers the movement of the sliding elements along the base surface. The movement of the sliding elements in the corner units can also be generated, for example, by a lever mechanism, electromechanically, or hydraulically.

[0003] To use the inner formwork for concrete pouring, the sliding elements are moved away from each other outwards until they are flush with the outer surfaces of the corner units, and so that the outer surfaces of the corner units and the outer surfaces of the formwork panels are in a common plane. Once the concrete pouring has taken place and the concrete has reached the required hardness, the sliding elements can be moved back towards each other along the base surface by rotating the spindle with the appropriate tool key, thus reducing the distance between two opposing formwork panels.Furthermore, the corner units move slightly towards the center of the inner formwork, allowing the inner formwork to be detached from the section of the concrete shaft. This enables it to be raised to the next higher level, for example, when constructing a shaft extending lengthwise along a vertical axis. The spindle is then set in rotation again to return the inner formwork to its usable dimensions.

[0004] The area between the sliding elements and the base surface of the main element forms a sliding contact. Once the sliding elements on the main elements are extended outwards, the joint between the main element and the sliding elements borders the area where the concrete will be poured. During the concrete pour, concrete adhesive can enter this joint, i.e., the contact area between the base surface of the main element and the sliding elements, where it hardens along with the concrete. After the concrete has hardened, a strong adhesive bond often forms between the inner formwork and the poured concrete. This bond must be broken to remove the inner formwork.

[0005] It is also known that workers on site often use crowbars to detach the inner formwork, and especially the corner units (particularly the last remaining corner unit), from the hardened concrete. The workers apply the crowbar to the edges of the outer sheet metal where the concrete has dried and hardened, which quickly leads to deformation and thus defects in the corner units. REVELATION OF THE INVENTION

[0006] The object of the invention is to improve an inner formwork for concrete construction, in particular shaft inner formwork, which can be detached from the fully hardened concrete casting in the simplest possible way.

[0007] This problem is solved starting from an inner formwork according to the preamble of claim 1 and starting from a corner unit according to the preamble of claim 11 in conjunction with the respective characterizing features. Advantageous embodiments of the invention are specified in the respective dependent claims.

[0008] To solve the problem preceding the invention, the invention provides the technical teaching that at least one pressing-off means is provided on the base element with which the base element can be pressed off from the finished concrete casting.

[0009] The core concept of the invention is the use of a release tool, which can be used as an alternative to a crowbar, to detach the base element from the finished concrete casting. For this purpose, the release tool can include a force application element to selectively detach the corner element and its base element from the concrete casting. In particular, a corner element can have several release tools arranged on the base element, which are activated simultaneously or at least sequentially in order to ultimately detach the corner element from the finished concrete without damage. The invention is inspired by release tools such as those known from shaft-hub connections, where so-called release screws can be used.The invention consists in equipping the corner element and, in particular, the base element with impression materials in order to build up an impression force from the corner element against the finished concrete casting, particularly using a screw force, until the corner element has finally detached from the concrete casting.

[0010] The removal device can therefore include at least one screw element that can be rotated to remove the base element from the finished concrete casting. In particular, the screw element can include a fine thread to enable a particularly high removal force with the same tightening torque. Furthermore, a threaded element can be arranged on the base element into which the screw element is screwed, the threaded element preferably being formed by a commercially available nut.

[0011] Furthermore, it is possible to install a reinforcing plate, which is welded to the inside of a casing sheet of the base element to achieve the most even distribution of force into the casing sheet. Without the use of a reinforcing plate, the casing sheet could deform plastically if a particularly large pressing force is applied at a single point with the casting material, and yet the casing sheet might not initially detach from the finished concrete casting. However, the reinforcing plate should also not be too large or too rigid, since the optimal release of the base element, which is bonded to the concrete casting by its casing sheet, is achieved through a peeling process. During this process, the casing sheet should deform slightly elastically, allowing the separation of the casing sheet from the concrete casting to begin at a single point and then spread out over a larger area.Therefore, the reinforcement plate should, for example, have a main dimension of 40 mm to 100 mm and / or 50 mm to 60 mm. The threaded element can be mounted on the reinforcement plate and / or at least partially screwed into it. Preferably, however, the threaded element is welded to the reinforcement plate or mounted in a replaceable manner.

[0012] A further advantage is the inclusion of a pressure plate, which is seated in an opening in the base element to apply pressure against the finished concrete casting. When the ejector is not activated, the pressure plate can tightly seal the opening to prevent concrete slurry from penetrating the base element. Preferably, the pressure plate is replaceably attached to the end face of the screw element and secured, for example, with a transversely inserted bolt, a snap ring, or a U-shaped clamp, so that the pressure plate does not necessarily have to rotate with the screw element. It is even conceivable that a sealing element is incorporated in conjunction with the screw element and / or the pressure plate to prevent concrete slurry from penetrating the base element.

[0013] The invention further relates to a corner unit of an inner formwork for concrete construction, comprising a base element and two sliding elements to which the formwork panels are attached, wherein the sliding elements can be moved along a base surface of the base element by activating a spindle or a push rod. According to the invention, at least one release mechanism is provided on the base element, with which the base element can be released from the finished concrete casting. The further features and associated advantages described above in connection with the inner formwork also apply to the corner unit according to the invention. PREFERRED EXAMPLE OF THE INVENTION

[0014] Further measures improving the invention are described in more detail below, together with a description of preferred embodiments for implementing the invention with reference to the figures. The figures show: Fig. 1. An overall view of an internal formwork with four corner units and formwork panels arranged between them in a top view. Fig. 2 a corner unit in a first perspective view, Fig. 3 a corner unit in a second perspective view, Fig. 4 a detailed view of the pressing agent in arrangement on the base element and Fig. 5 a detailed view of the screw element of the pressure-reducing device.

[0015] Fig. Figure 1 shows a top view of an inner formwork 1, which is regularly referred to as shaft formwork for the construction of closed shafts. The inner formwork 1 serves to form the interior of shafts in building construction, for example, in high-rise buildings. Such shafts include elevator shafts, utility shafts, stairwells, and the like. Once the inner formwork 1 is positioned in the emerging structure, reinforcing steel is placed around it, with an outer formwork following behind the reinforcing steel. The area between the outer surface of the inner formwork 1 and the outer formwork is then filled with a concrete pour, which subsequently hardens or sets.Once the concrete on the outside of the inner formwork 1 has hardened, it must be detached from the inside of the completed shaft section in order to be pulled upwards for a subsequent section, so that the process of positioning the inner formwork 1 is repeated.

[0016] The inner formwork 1 has corner units 10, each comprising a base element 12 and two sliding elements 13. Formwork panels 11 are located between the sliding elements 13 of two adjacent corner units 10, so that in the arrangement of the inner formwork 1 shown, a rectangular or, as shown, a square surface of the inner formwork 1 is formed for the shaft concrete casting.

[0017] Once the concrete pour has taken place and the concrete has sufficiently hardened, the inner formwork 1 must be removed. For this purpose, push rods 14 are moved axially, i.e., in a direction perpendicular to the image plane, using a pry bar. This causes the sliding elements 13 of each of the corner units 10 to move towards each other. As a result, the outer dimensions of the inner formwork 1 decrease, and the formwork panels 11 and the corner units 10 detach from the hardened or set concrete.

[0018] As the sliding elements 13 are moved, they move towards each other, thereby reducing the distance between the opposing formwork panels 11, so that the formwork panels 11 can eventually be detached from the finished concrete casting. Due to the kinematics generated by the movement of the sliding elements 13 on the base elements 12, the corner units 10 also detach from the finished cast corners of the shaft, and the inner formwork 1 is separated from the concrete casting and can, for example, be moved upwards by a crane.

[0019] The Fig. 2 and Fig. Figures 3 each show a perspective view of a corner unit 10, comprising a base element 12 on which two sliding elements 13, movable relative to each other, are arranged. To move the sliding elements 13 relative to each other, a push rod 14 must be displaced axially, i.e., in the vertical direction as shown. For this purpose, the push rod 14 is operatively connected to the sliding elements 13 via lever elements 21 (visible in Figure 3). Fig. 2) such that an axial displacement of the push rod 14 in the vertical direction causes a lateral displacement of the sliding elements 13. In this way, the sliding elements 13 can be moved towards each other to release the inner formwork from the concrete casting, and the sliding elements can be moved away from each other to reposition the inner formwork.

[0020] Fig. Figure 3 shows several release devices 15 on the outer surface of the casing plate 22 of the base element 12 of the corner unit 10. The release devices 15 can be extended from the inside of the base element 12 outwards from the plane of the casing plate 22. This allows the casing plate 22 to be pressed off the finished concrete casting, preferably by activating the release devices 15 simultaneously or at least sequentially. At least one release device 15 should be located in the middle area of ​​the 1.2 m high shaft corner, and at the other heights, at least one release device 15 should always be located approximately 60 cm from the top or bottom edge.

[0021] The lower edge of the shaft corner should be provided for at a distance, since concrete is not always poured up to the top edge of the inner formwork and the function of the pressing device 15 requires a concrete lining, because if the concrete is not poured to such a height, the upper pressing device 15 cannot press the corner unit 10, but runs into empty space.

[0022] Fig. Figure 4 shows a cross-sectional view through the base element 12, so that part of the outer sheet 22 is visible, and inside the base element 12 is the push rod 14, to which the two lever elements 21 are attached for the lateral movement of the sliding elements 13 when the push rod 14 is moved up and down perpendicular to the plane of the image.

[0023] The impression element 15 has a screw-in element 16 that is screwed into a threaded element 17. A pressure plate 19 is located on the end face of the screw element 16, which closes an opening 20 in the outer sheet 22. The threaded element 17 is received in a receptacle 23, and the receptacle 23 is, by way of example, welded to a reinforcement plate 18, which in turn is welded to the inside of the outer sheet 22. The reinforcement plate 18 serves to distribute the pressing force more broadly into the outer sheet 22, so that, even with a high adhesive effect of the concrete casting on the outside of the outer sheet 22 and a correspondingly high pressing force, the sheet 22 does not deform plastically, and thus no bulging can occur.

[0024] In the illustrated state, the pressure plate 19 closes the opening 20. A tight seal of the opening 20 with the pressure plate 19 can be achieved by unscrewing the screw element 16 as far as possible from the threaded element 17, so that the pressure plate 19 is essentially pulled backwards into the opening 20, which has slightly beveled edges. If, on the other hand, the ejector 15 is to be activated, the screw element 16 is set in rotation so that the pressure plate 19 extends slightly out of the opening 20 and protrudes beyond the outer surface of the casing plate 22. In this way, the pressure plate 19 can be pressed against the finished concrete casting (not shown in detail), thereby separating the base element 12 and, consequently, the corner unit 10 from the finished concrete casting.

[0025] The accessibility of the screw element 16 within the base body 12 of the corner unit 10 is ensured in such a way that it can be set in rotation with a wrench, a ratchet or even an impact wrench.

[0026] Fig. Figure 5 schematically depicts the front area of ​​the screw element 16, to which the pressure plate 19 is attached. The pressure plate 19 closes the opening 20 in the casing plate 22, whereby the gap 24 shown as an example between the pressure plate 19 and the opening 20 can also be completely closed if the screw element 16 is pulled back to the left in the plane of the image.

[0027] To attach the pressure plate 19 to the screw element 16 in an interchangeable manner, a transversely inserted bolt 25 serves as an example. This bolt 25 can also incorporate a locking element (not shown in detail), and can also be formed by a cotter pin or the like. It is also conceivable to attach the pressure plate 19 to the screw element 16, for example, with a snap ring or a clamping element, such that the screw element 16 can rotate without the pressure plate 19 rotating with it. This is possible if the locking mechanism is a circumferential groove at the front end of the screw element 16.

[0028] The invention is not limited in its implementation to the preferred embodiment described above. Rather, a number of variants are conceivable, which utilize the solution presented even in fundamentally different designs. All features and / or advantages arising from the claims, the description, or the drawings, including design details or spatial arrangements, can be essential to the invention, both individually and in various combinations. Reference symbol list: 1 Inner formwork 10 corner unit 11 Switchboard 12 Basic Element 13 Sliding element 14 Push rod 15 Pressing agents 16 screw element 17 Threaded element 18 Reinforcement plate 19 Printing plate 20 Opening 21 Lever element 22 Sheathing sheet 23 Mounting for threaded element 24 columns 25 sealing element QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 104295091 A

[0002]

Claims

[1] Internal formwork (1) for concrete construction, comprising a number of corner units (10) between which formwork panels (11) are arranged, wherein the corner units (10) have a base element (12) and two sliding elements (13) to which the formwork panels (11) are attached, and wherein the sliding elements (13) are movable along a base surface of the base element (12) by activating a spindle or a push rod (14), characterized by , that at least one release device (15) is provided on the base element (12) with which the base element (12) can be released from the finished concrete casting. [2] Inner formwork (1) according to claim 1, characterized by , that the release means (15) has at least one screw element (16) which can be rotated to release the base element (12) from the finished concrete casting. [3] Inner formwork (1) according to claim 2, characterized by, that a threaded element (17) is arranged on the base element (12), into which the screw element (16) is screwed. [4] Inner formwork (1) according to claim 3, characterized by , that the threaded element (17) is formed by a commercially available screw nut. [5] Inner formwork (1) according to any of the preceding claims, characterized by , that a reinforcement plate (18) is provided which is welded to the inside of a shell plate (22) of the base element (12). [6] Inner formwork (1) according to claim 5, characterized by , that the threaded element (17) is received on the reinforcement plate (18). [7] Inner formwork (1) according to claim 6, characterized by , that the threaded element (17) is welded to the reinforcement plate (18) or is interchangeably mounted. [8] Inner formwork (1) according to any of the preceding claims, characterized by, that a pressure plate (19) is provided which sits in an opening (20) in the base element (12) to apply pressure against the finished concrete casting. [9] Inner formwork (1) according to claim 8, characterized by , that the pressure plate (19) in the non-activated state of the ejector (15) tightly closes the opening (20) to prevent the penetration of concrete adhesive into the base element (12). [10] Inner formwork (1) according to any of the preceding claims, characterized by , that in conjunction with the screw element (16) and / or with the pressure plate (19) a sealing element (25) is provided to prevent the penetration of concrete adhesive into the base element (12). [11] Corner unit (10) of an internal formwork (1) for concrete construction, comprising a base element (12) and two sliding elements (13) to which the formwork panels (11) are attached, and wherein the sliding elements (13) are movable along a base surface of the base element (12) by activating a spindle or a push rod (14), characterized by , that at least one release device (15) is provided on the base element (12) with which the base element (12) can be released from the finished concrete casting.

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